Patient acceptable symptom states after totalhip or knee replacement at mid-term follow-up: Thresholds of the Oxford hip and knee scores

Patients Aged 40 Years and Older Demonstrate Durable and Comparable Results to Patients Aged Less Than 40 Years After Primary Hip Arthroscopy for Femoroacetabular Impingement Syndrome: A Propensity Matched Study at Minimum 10-Year Follow-Up

PURPOSE

To compare clinical outcomes and rates of secondary surgery, including revision hip arthroscopy and conversion to total hip arthroplasty (THA), after primary hip arthroscopy for femoroacetabular impingement syndrome (FAIS) in patients ≥40 years of age at minimum 10-year follow-up compared with a propensity-matched control group of patients <40 years.

METHODS

A retrospective cohort study was performed for patients who underwent primary hip arthroscopy for FAIS between January 2012 and February 2013. Patients ≥40 years old were propensity matched in a 1:1 ratio by sex and body mass index to patients <40 years old. Patient-reported outcomes (PROs) including Hip Outcome Score for Activities of Daily Living and Sports-Specific subscales, modified Harris Hip, International Hip Outcome Tool-12, and Visual Analog Scale for Pain and Satisfaction were collected. Rates of minimal clinically important difference (MCID) and patient-acceptable symptomatic state (PASS) achievement at 10 years were evaluated and compared between groups. Rates of secondary surgery including revision hip arthroscopy and conversion to THA were evaluated. Gross survivorship between cohorts was evaluated using a Kaplan-Meier curve.

RESULTS

Fifty-three patients aged ≥40 (age 48.3 ± 5.8 years) were successfully matched to 53 patients aged <40 (age: 28.9 ± 7.2, <0.001). There were no other preoperative group differences regarding patient demographics, characteristics, or radiographic findings. Both groups demonstrated significant improvement regarding all PROs at a minimum of 10 years' follow-up (P < .001 for all). No significant difference was noted between cohorts regarding any delta (preoperative to 10-year postoperative) scores (P > .05 for all). High rates of MCID and PASS achievement were achieved in both cohorts, with no significant differences in any PRO measure (P > .05 for all). No significant differences in rates of complications (age ≥40: 2.0%, age <40: 7.7%, P = .363), rates of revision (age ≥40: 7.5%, age <40: 9.4%, P = .999), or conversion to THA (age ≥40: 13.2%, age <40: 3.8%, P = .161) were identified. On Kaplan-Meier analysis, no significant difference (P = .321) was demonstrated in overall gross survivorship between cohorts.

CONCLUSIONS

Patients with age ≥40 with FAIS undergoing primary hip arthroscopy demonstrated durable and comparable 10-year PRO and rates of MCID and PASS achievement compared with a propensity-matched cohort of age <40 counterparts.

LEVEL OF EVIDENCE

Level III, retrospective comparative prognostic trial.

Which factors are associated with a successful outcome following total hip arthroplasty in patients with early radiographic osteoarthritis?

BACKGROUND

It is unclear which factors are associated with a successful total hip arthroplasty (THA) in patients with early radiographic osteoarthritis (OA).

METHODS

70 patients with early OA (Kellgren and Lawrence [KL] grades 0-2) who underwent THA were compared with 200 patients with advanced OA (KL grades 3-4). Outcomes were Oxford Hip Scores (OHS), EQ-5D and EQ-VAS scores; compared preoperatively with 1 year postoperatively. We investigated which clinical and radiographic (plain x-ray, CT, MRI) features predicted successful THA (postoperative OHS ⩾42).

RESULTS

The early OA group were significantly younger (61 vs. 66 years; [p = 0.0035). There were no significant differences in BMI, ASA grade or gender. After adjusting for confounders, the advanced OA group had a significantly greater percentage of possible change (PoPC) in OHS (75.8% vs. 50.4%; p < 0.0001) and improvement in EQ-5D (0.151 vs. 0.002; p < 0.0001). There were no significant differences in complication, revision or readmission rates. In the early OA group, 16/70 (22.9%) patients had a 'successful' THA. Patients who had a 'successful' THA were significantly more likely to have subchondral cysts on CT/MRI (91.7% vs. 57.7%; p = 0.0362). The presence of cysts on CT/MRI was associated with a significantly greater PoPC in OHS (61.6% vs. 38.2%; p = 0.0353). The combination of cysts and joint space width <1 mm was associated with a PoPC of 68%.

CONCLUSIONS

THA in patients with early OA (KL grades 0-2) on plain radiographs should be indicated with caution. We advocate preoperative cross-sectional imaging in these patients. In the absence of cysts on CT/MRI, a THA seems unlikely to provide a satisfactory outcome.

Defining the Minimal Clinically Important Difference (MCID) and Patient Acceptable Symptom State (PASS) at 2 years following open gluteus medius and/or minimus repair

To define Minimally Clinically Important Difference (MCID) and Patient Acceptable Symptomatic State (PASS) threshold scores after open gluteus medius and/or minimus repair. Primary open gluteus medius and/or minimus repair patients from November 2013 to March 2020 were identified. Patient reported outcomes (PROs) were assessed preoperatively, 1- and 2-year follow-up, including the Hip Outcome Score Activities of Daily Living (HOS-ADL), modified Harris Hip Score (mHHS), International Hip Outcome Tool-12 (iHOT-12) and Visual Analog Scale (VAS) Pain. Thresholds for achieving a MCID and PASS postoperatively were calculated using the distribution method and receiver operator curve analysis; 25 patients (24 females, 1 male, age: 69 ± 6.8 years, body mass index: 26.9 ± 5.0 kg/m2) were included in final analyses. MCID threshold scores for HOS-ADL, mHHS, iHOT-12 and VAS Pain were calculated as 11.1, 6.2, 15.3 and 14.0, respectively. PASS threshold scores for each of the PROs were as follows: HOS-ADL (71.9), mHHS (60.0), iHOT-12 (49.2) and VAS Pain (36.8). MCID thresholds for HOS-ADL, mHHS, iHOT-12 and VAS Pain were achieved by 58.3%, 83.3%, 66.7% and 57.1% of patients, respectively. PASS thresholds for HOS-ADL, mHHS, iHOT-12 and VAS Pain were achieved by 52.4%, 44.8%, 65% and 59.1% of patients, respectively. Open gluteus medius and/or minimus repair results in a high rate of achievement of clinically significant outcomes at a minimum of 2 years postoperatively. MCID threshold values for HOS-ADL, mHHS, iHOT-12 and VAS Pain were 11.1, 6.2, 15.3 and 14.0, respectively. PASS threshold values for HOS-ADL, mHHS, iHOT-12 and VAS Pain were 71.9, 60.0, 49.2 and 36.8, respectively. The majority of patients achieved clinically significant outcomes with 81.3% and 77.3% achieving MCID and PASS for at least one PRO, respectively.

Anxiety and depression prior to total knee arthroplasty are associated with worse pain and subjective function: A prospective comparative study

PURPOSE

The aim of this study was to investigate the influence of preoperative anxiety and depression on subjective function, pain and revision rates following total knee arthroplasty (TKA).

METHODS

A prospective comparative study was conducted, including 349 patients undergoing TKA surgery between January 2019 and April 2021. Patients completed the Hospital Anxiety and Depression Scale (HADS) questionnaire preoperatively, and a set of Patient-Reported Outcome Measures (PROMs) preoperatively and at 6, 12 and 24 months postoperatively. Patients were categorized into anxiety and depression groups based on HADS scores. PROMs included the Knee injury and Osteoarthritis Outcome Score-Physical Function Shortform (KOOS-PS), Oxford Knee Score (OKS) and NRS-Pain. Differences in PROM scores between the anxiety/depression group and, respectively, nonanxiety/nondepression group were assessed, as well as differences in minimal clinical important difference (MCID) and attainment of Patient Acceptable Symptom State (PASS). Lastly, revision rates were compared.

RESULTS

Anxiety and depression groups exhibited inferior subjective function preoperatively and postoperatively compared to nonanxiety and nondepression groups (all p < 0.05), experienced more pain preoperatively (p < 0.001) and also postoperatively for depression patients (all p < 0.05). Significantly fewer patients with anxiety and depression reached the PASS for KOOS-PS, OKS and NRS-Pain (all p < 0.05). There were no differences in the proportion of patients reaching the MCID for all PROMs (all p > 0.060), and revision rates did not differ between groups (both p > 0.96).

CONCLUSION

Preoperative anxiety and depression negatively influence subjective function and pain preoperatively and up to 2-year follow-up in patients undergoing TKA. Revision rates did not differ between groups, and there were no relevant differences in clinical improvement of subjective function and pain.

LEVEL OF EVIDENCE

Level II, prospective comparative study.

Open and Endoscopic Gluteus Medius and/or Minimus Repair Achieves Clinical Success Regardless of Tear Grade: High-Grade Fatty Infiltration Portends Worse Outcomes

PURPOSE

To evaluate minimum 2-year gluteus medius and/or minimus repair clinical success rates stratified by the 3-grade magnetic resonance imaging (MRI)-based classification (MRI grade) and to evaluate clinical success rates by the surgical approach used at each MRI grade and by the Goutallier-Fuchs (GF) classification.

METHODS

A retrospective review identified patients who underwent primary endoscopic or open gluteus medius and/or minimus repair from 2012 to 2021 performed by a single surgeon. Preoperative MRI scans were classified using the MRI grade and GF classification. Patient-reported outcomes were collected preoperatively and at minimum 2-year follow-up. Cohort-specific minimal clinically important difference and patient acceptable symptom state achievement was recorded. Rates of clinical success, defined as achievement of the 2-year minimal clinically important difference or patient acceptable symptom state with avoidance of revision surgery, were compared by MRI grade, by surgical approach at each MRI grade, and by GF classification.

RESULTS

A total of 112 patients (71 with MRI grade 1, 19 with grade 2, and 22 with grade 3) were included. MRI grade 1 patients underwent endoscopic repair (P < .001) more often than the other groups. The overall clinical success rate was 90%. Clinical success rates by MRI grade were 93% for grade 1, 95% for grade 2, and 77% for grade 3 (P = .087). Clinical success rates by the endoscopic and open surgical approaches used at each MRI grade were 93% versus 90% for grade 1 (P = .543), 91% versus 100% for grade 2 (P > .999), and 60% versus 92% for grade 3 (P = .135). GF grade 1 tears achieved a higher rate of clinical success than GF grade 4 tears (100% vs 71%, P = .030).

CONCLUSIONS

Primary repair of gluteus medius and/or minimus tears resulted in clinical success in most patients irrespective of MRI grade and irrespective of the surgical approach used at each MRI grade, yet GF grade 1 tears showed a significantly higher clinical success rate than GF grade 4 tears.

LEVEL OF EVIDENCE

Level IV, prognostic retrospective case series.

Outcome Scores and Survivorship of Patients Undergoing Primary Hip Arthroscopy With Borderline Hip Dysplasia: A Propensity-Matched Study With Minimum 10-Year Follow-up

BACKGROUND

Patients with borderline hip dysplasia (BHD) and concomitant femoroacetabular impingement syndrome (FAIS) have demonstrated similar outcomes at short- and midterm follow-up compared with equivalent patients without dysplasia. However, comparisons between these groups at long-term follow-up have yet to be investigated.

PURPOSE

To compare long-term clinical outcomes between patients with BHD undergoing primary hip arthroscopy for FAIS versus matched control patients without BHD.

STUDY DESIGN

Cohort study; Level of evidence, 2.

METHODS

A retrospective cohort study was conducted on patients with BHD (lateral center-edge angle, 18°-25°) who underwent hip arthroscopy for FAIS between January 2012 and February 2013. Patients were propensity matched in a 1:3 ratio by age, sex, and body mass index to control patients without BHD who underwent primary hip arthroscopy. Groups were compared in terms of patient-reported outcomes (PROs) preoperatively and at 10 years postoperatively, including the Hip Outcome Score Activities of Daily Living subscale (HOS-ADL) and Sports subscale (HOS-SS), modified Harris Hip Score, 12-item International Hip Outcome Tool, visual analog scale (VAS) for pain and satisfaction. Achievement rates for minimal clinically important difference (MCID) and Patient Acceptable Symptom State (PASS) were compared between groups. Kaplan-Meier survivorship curves were assessed between groups.

RESULTS

At a mean follow-up of 10.3 ± 0.3 years, 28 patients with BHD (20 women; age, 30.8 ± 10.8 years) were matched to 84 controls who underwent primary hip arthroscopy. Both groups significantly improved from preoperative assessment in all PRO measures at 10 years (P < .001 for all). PRO scores were similar between groups, aside from HOS-SS (BHD, 62.9 ± 31.9 vs controls, 80.1 ± 26.0; P = .030). Rates of MCID achievement were similar between groups for all PROs (HOS-ADL: BHD, 76.2% vs controls, 67.9%, P = .580; HOS-SS: BHD, 63.2% vs controls, 69.4%, P = .773; modified Harris Hip Score: BHD, 76.5% vs controls, 67.9%, P = .561; VAS pain: BHD, 75.0% vs controls, 91.7%, P = .110). Rates of PASS achievement were significantly lower in the BHD group for HOS-ADL (BHD, 39.1% vs controls, 77.4%; P = .002), HOS-SS (BHD, 45.5% vs controls, 84.7%; P = .001), and VAS pain (BHD, 50.0% vs controls, 78.5%; P = .015). No significant difference was found in the rate of subsequent reoperation on the index hip between groups. Kaplan-Meier survival analysis demonstrated comparable survivorship at long-term follow-up (P = .645).

CONCLUSION

After primary hip arthroscopy, patients with BHD in the setting of FAIS had significantly improved PRO scores at 10-year follow-up, comparable with propensity-matched controls without BHD. Rates of MCID achievement were similar between groups, although patients with BHD had lower rates of PASS achievement. Patients with BHD had similar long-term hip arthroscopy survivorship compared with controls, with no significant difference in rates of revision hip arthroscopy or conversion to total hip arthroplasty.

Patient Acceptable Symptom State Thresholds for the Knee Society Score, Oxford Knee Score, and 36-Item Short Form Survey Ten Years Following Unicompartmental Knee Arthroplasty

BACKGROUND

The patient acceptable symptom state (PASS) refers to a cutoff value on any patient-reported outcome measures (PROMs) scale, beyond which patients consider themselves as having achieved an acceptable outcome. This study aimed to identify PASS thresholds for knee-specific and generic PROMs at 10 years post-unicompartmental knee arthroplasty (UKA).

METHODS

There were 269 patients who underwent UKA for medial osteoarthritis from 2004 to 2007 at a single institution and were surveyed preoperatively and 10 years postoperatively using the Knee Society Function Score (KSFS), Knee Society Knee Score (KSKS), Oxford Knee Score (OKS), 36-Item Short Form Survey (SF-36) Mental Component Score (MCS), and SF-36 Physical Component Score (PCS). Treatment outcomes and expectations were assessed using an anchor question, and PASS attainment was determined using the Youden index on a receiver operating characteristic (ROC) curve. Also, a similar study that identified 2-year long-term PROM PASS thresholds for UKA was referenced and compared.

RESULTS

Overall, 91.1% reported acceptable outcomes. The area under the curve for ROCs of KSKS, OKS, and PCS were 0.80, 0.75, and 0.71, respectively. The area under the curve for ROCs of KSFS and MCS were both 0.64. The PASS thresholds were 67.5 for KSFS, 70.5 for KSKS, 39.5 for OKS, 44.6 for PCS, and 43.8 for MCS. Patients who achieved a PASS were at least 3 times more likely to have satisfactory outcomes.

CONCLUSIONS

To our knowledge, this is the first study that identified 10-year long-term PROM PASS thresholds for UKA. Accounting for our finding that a decade-long follow-up yielded lower PASS thresholds, time-specific UKA PROM PASS thresholds should be considered.

LEVEL OF EVIDENCE

III.

Defining Patient-relevant Thresholds and Change Scores for the HOOS JR and KOOS JR Anchored on the Patient-acceptable Symptom State Question

BACKGROUND

When evaluating the results of clinical research studies, readers need to know that patients perceive effect sizes, not p values. Knowing the minimum clinically important difference (MCID) and the patient-acceptable symptom state (PASS) threshold for patient-reported outcome measures helps us to ascertain whether our interventions result in improvements that are large enough for patients to care about, and whether our treatments alleviate patient symptoms sufficiently. Prior studies have developed the MCID and PASS threshold for the Hip Disability and Osteoarthritis Outcome Score for Joint Replacement (HOOS JR) and Knee Injury and Osteoarthritis Outcome Score for Joint Replacement (KOOS JR) anchored on satisfaction with surgery, but to our knowledge, neither the MCID nor the PASS thresholds for these instruments anchored on a single-item PASS question have been described.

QUESTIONS/PURPOSES

(1) What are the MCID (defined here as the HOOS/KOOS JR change score associated with achieving PASS) and PASS threshold for the HOOS JR and KOOS JR anchored on patient responses to the single-item PASS instrument? (2) How do patient demographic factors such as age, gender, and BMI correlate with MCID and PASS thresholds using the single-item PASS instrument?

METHODS

Between July 2020 and September 2021, a total of 10,970 patients underwent one primary unilateral THA or TKA and completed at least one of the three surveys (preoperative HOOS or KOOS JR, 1-year postoperative HOOS or KOOS JR, and 1-year postoperative single-item anchor) at one large, academic medical center. Of those, only patients with data for all three surveys were eligible, leaving 13% (1465 total; 783 THAs and 682 TKAs) for analysis. Despite this low percentage, the overall sample size was large, and there was little difference between completers and noncompleters in terms of demographics or baseline patient-reported outcome measure scores. Patients undergoing bilateral total joint arthroplasty or revision total joint arthroplasty and those without all three surveys at 1 year of follow-up were excluded. A receiver operating characteristic curve analysis, leveraging a 1-year, single-item PASS (that is, "Do you consider that your current state is satisfactory?" with possible answers of "yes" or "no") as the anchor was then used to establish the MCID and PASS thresholds among the 783 included patients who underwent primary unilateral THA and 682 patients who underwent primary unilateral TKA. We also explored the associations of age at the time of surgery (younger than 65 years or 65 years and older), gender (men or women), BMI (< 30 or ≥ 30 kg/m 2 ), and baseline Patient-Reported Outcome Measure Information System-10 physical and mental component scores (< 50 or ≥ 50) for each of the MCID and PASS thresholds through stratified analyses.

RESULTS

For the HOOS JR, the MCID associated with the PASS was 23 (95% CI 18 to 31), with an area under the receiver operating characteristic curve of 0.75, and the PASS threshold was 81 (95% CI 77 to 85), with an area under the receiver operating characteristic curve of 0.81. For the KOOS JR, the MCID was 16 (95% CI 14 to 18), with an area under the receiver operating characteristic curve of 0.75, and the PASS threshold was 71 (95% CI 66 to 73) with an area under the receiver operating characteristic curve of 0.84. Stratified analyses indicated higher change scores and PASS threshold for younger men undergoing THA and higher PASS thresholds for older women undergoing TKA.

CONCLUSION

Here, we demonstrated the utility of a single patient-centered anchor question, raising the question as to whether simply collecting a postoperative PASS is an easier way to measure success than collecting preoperative and postoperative patient-reported outcome measures and then calculating MCIDs and the substantial clinical benefit.

LEVEL OF EVIDENCE

Level III, therapeutic study.

Patients With Lateral and Anterolateral Cam Morphology Have Greater Deformities Versus Typical Anterolateral Deformity Alone but No Differences in Postoperative Outcomes: A Propensity-Matched Analysis at Minimum 5-Year Follow-Up

PURPOSE

To compare pre- and postoperative findings between patients undergoing hip arthroscopy for femoroacetabular impingement syndrome with lateral impingement versus those without lateral impingement METHODS: Patients who underwent primary hip arthroscopy for femoroacetabular impingement syndrome between 2012 and 2017 with minimum 5-year follow-up were included. Alpha angle (AA) was measured on preoperative anteroposterior (AP) and 90° Dunn radiographs. Patients with AA >60° on Dunn view but not AP view (no lateral impingement) were propensity matched by sex, age, and body mass index in a 1:3 ratio to patients with AA >60° on both views (lateral impingement). Demographic characteristics, radiographic and intraoperative findings, reoperation rates, and patient-reported outcomes (PROs) were compared between groups. Categorical variables were compared using the Fisher exact testing and continuous variable using 2-tailed Student t tests.

RESULTS

Sixty patients with lateral impingement (65.0% female, age: 35.3 ± 13.0 years) were matched to 180 patients without lateral impingement (65.0% female, age: 34.7 ± 12.5 years, P ≥ .279). Patients with lateral impingement had larger preoperative AAs on both Dunn (71.0° ± 8.8° vs 67.6° ± 6.1°, P = .001) and AP radiographs (79.0° ± 12.1° vs 48.2° ± 6.5°, P < .001). However, there were no differences in postoperative AAs on either view (Dunn: 39.0° ± 6.1° vs 40.5° ± 5.3°, AP: 45.8° ± 9.0° vs 44.9° ± 7.0°, P ≥ .074). Labral tears began more superiorly in patients with lateral impingement (12:00 ± 0:49 vs 12:17 ± 0:41, P = .030), and they demonstrated greater rates of acetabular and femoral cartilage damage (P = .030 for both); however, there were no differences in PROs or reoperation rates between the groups at 5-year follow-up.

CONCLUSIONS

Although cam deformities located laterally and anterolaterally are larger than those located anterolaterally alone, both can be resected adequately, resulting in similar postoperative radiographic measurements, PROs, and survivorship.

LEVEL OF EVIDENCE

Level III, retrospective cohort study.

Association Between Proximal Hamstring Tear Characteristics and Achievement of Clinically Significant Outcomes After Endoscopic and Open Repair at Minimum 2-Year Follow-up

BACKGROUND

The effect of preoperative tear characteristics and the relative efficacy of open versus endoscopic surgical techniques have not been elucidated for the surgical treatment of proximal hamstring tendon injuries.

PURPOSE

(1) To report on achievement rates of clinically significant outcomes at a minimum 2-year follow-up for multiple patient-reported outcomes (PROs) after surgical treatment of proximal hamstring injuries, stratified according to severity of proximal hamstring injury, and (2) to compare clinical outcomes associated with endoscopic versus open surgical repair for a subset of similarly classified tears.

STUDY DESIGN

Cohort study; Level of evidence, 3.

METHODS

A single-surgeon clinical registry was queried for patients who underwent surgical repair for proximal hamstring ruptures between January 2012 and March 2021. Injuries were classified by magnetic resonance imaging as follows: grade 1, incomplete tear with the involvement of 1 or 2 tendons; grade 2, complete tear with the involvement of 3 tendons and ≤2-cm retraction; and grade 3, complete tear with the involvement of 3 tendons and >2-cm retraction. The Patient Acceptable Symptom State (PASS) for multiple PROs was calculated and compared among injury grades and between surgical techniques.

RESULTS

Among 75 patients with a mean follow-up of 30.5 ± 5.1 months, 20 had grade 1 tears, 24 had grade 2 tears, and 31 had grade 3 tears. Favorable 2-year postoperative PROs were demonstrated by each grade for all measured PROs. Patients with grade 3 tears were noted to have significantly lower rates of 2-year PASS achievement for the Hip Outcome Score-Activities of Daily Living (HOS-ADL) and Hip Outcome Score-Sports Specific (HOS-SS) scales (P≤ .032). Among grade 2 tears, patients treated endoscopically demonstrated significantly greater HOS-SS (endoscopic, 91.7%; open, 58.3%; P = .045) and Patient-Reported Outcomes Measurement Information System for Physical Function (endoscopic, 80.0%; open, 50.0%; P = .033) PASS achievement rates compared with those treated with the open technique. Complication rates were highest in patients with grade 3 tears (45.2%, P = .043).

CONCLUSION

Surgical repair of proximal hamstring tendon tears with varying extents of tendon retraction resulted in high rates of achieving PASS at the 2-year follow-up. Among complete tears with <2 cm of retraction, endoscopic repairs exhibited equal or higher rates of achieving PASS compared with open repairs across multiple PROs at 2 years postoperatively. However, patients with complete tears and retraction >2 cm achieved lower rates of PASS on the HOS-ADL and HOS-SS scales and had a higher rate of complications.

The Gluteus-Score-7 Predicts the Likelihood of Both Clinical Success and Failure Following Surgical Repair of the Hip Gluteus Medius and/or Minimus

PURPOSE

To identify patient preoperative history, examination, and imaging characteristics that increase the risk of postoperative failure of gluteus medius/minimus repair, and to develop a decision-making aid predictive of clinical outcomes for patients undergoing gluteus medius/minimus repair.

METHODS

Patients from 2012 to 2020 at a single institution undergoing gluteus medius/minimus repair with minimum 2-year follow-up were identified. MRIs were graded according to the "three-grade" classification system: grade 1: partial-thickness tear, grade 2: full-thickness tears with <2 cm of retraction, grade 3: full-thickness tears with ≥2 cm retraction. Failure was defined as undergoing revision within 2 years postoperatively or not achieving both a cohort-calculated minimal clinically important difference (MCID) and responding "no" to patient acceptable symptom state (PASS). Inversely, success was defined as reaching both an MCID and responding "yes" to PASS. Predictors of failure were verified on logistic regression and a predictive scoring model, the Gluteus-Score-7, was generated to guide treatment-decision making.

RESULTS

In total, 30 of 142 patients (21.1%) were clinical failures at mean ± SD follow-up of 27.0 ± 5.2 months. Preoperative smoking (odds ratio [OR], 3.0; 95% confidence interval [CI], 1.0-8.4; P = .041), lower back pain (OR, 2.8; 95% CI, 1.1-7.3; P = .038), presence of a limp or Trendelenburg gait (OR, 3.8; 95% CI, 1.5-10.2; P = .006), history of psychiatric diagnosis (OR, 3.7; 95% CI, 1.3-10.8; P = .014), and increased MRI classification grades (P ≤ .042) were independent predictors of failure. The Gluteus-Score-7 was generated with each history/examination predictor assigned 1 point and MRI classes assigned corresponding 1-3 points (min 1, max 7 score). A score of ≥4/7 points was associated with risk of failure and a score ≤2/7 points was associated with clinical success.

CONCLUSIONS

Independent risk factors for revision or not achieving either MCID or PASS after gluteus medius and/or minimus tendon repair include smoking, preoperative lower back pain, psychiatric history, Trendelenburg gait, and full-thickness tears, especially tears with ≥2 cm retraction. The Gluteus-Score-7 tool incorporating these factors can identify patients at risk of both surgical treatment failure and success, which may be useful for clinical decision-making.

LEVEL OF EVIDENCE

Level IV, prognostic case series.

Hip Arthroscopic Surgery With Chondrolabral Refixation, Osteochondroplasty, and Routine Capsular Closure for Femoroacetabular Impingement Syndrome: Clinical Outcomes at a Minimum 10-Year Follow-up

BACKGROUND

Hip arthroscopic surgery for femoroacetabular impingement syndrome (FAIS) has proven to be an effective surgical intervention, with high rates of return to sport and work as well as favorable outcomes at short- and midterm follow-up. However, limited data exist on outcomes at long-term follow-up.

PURPOSE

To evaluate patient-reported outcomes (PROs) at a minimum 10-year follow-up after primary hip arthroscopic surgery including labral repair, femoral osteochondroplasty, acetabular osteochondroplasty, and capsular closure for FAIS.

STUDY DESIGN

Case series; Level of evidence, 4.

METHODS

Patients who underwent primary hip arthroscopic surgery for FAIS between June 2012 and January 2013 were identified. PROs were collected preoperatively and at a minimum of 10 years postoperatively, including the Hip Outcome Score-Activities of Daily Living (HOS-ADL), Hip Outcome Score-Sports Subscale (HOS-SS), modified Harris Hip Score (mHHS), International Hip Outcome Tool-12 (iHOT-12), and visual analog scale (VAS) for pain and satisfaction. Unique minimal clinically important difference (MCID) and patient acceptable symptom state (PASS) thresholds were calculated, and their rates of achievement were analyzed. An alpha level of <.05 was used to determine statistical significance.

RESULTS

A total of 94 patients (55 female; mean age, 34.3 ± 12.4 years) were analyzed with a mean follow-up of 10.1 ± 0.3 years (range, 10.0-10.7 years). Patients demonstrated significant 10-year improvement across all PRO measures (P < .001). MCID and PASS thresholds were calculated as follows: HOS-ADL (10.4 and 85.3, respectively), HOS-SS (14.6 and 60.2, respectively), mHHS (8.8 and 76.0, respectively), VAS pain (14.6 and 27.5, respectively), and iHOT-12 (PASS: 71.4). The majority of patients achieved the MCID and PASS for each PRO measure: HOS-ADL (73.4% and 70.9%, respectively), HOS-SS (78.5% and 77.2%, respectively), mHHS (81.0% and 70.9%, respectively), VAS pain (88.6% and 70.9%, respectively), and iHOT-12 (PASS: 73.4%). Overall, 9 patients (9.6%) underwent subsequent revision hip arthroscopic surgery at a mean 4.9 ± 3.7 years (range, 1.1-10.1 years) postoperatively, and 6 patients (6.4%) underwent conversion to total hip arthroplasty at a mean 4.1 ± 3.1 years (range, 0.9-9.3 years) postoperatively.

CONCLUSION

Patients who underwent primary hip arthroscopic surgery for FAIS utilizing contemporary methods of labral repair, acetabular and/or femoral osteochondroplasty, and capsular closure commonly experienced sustained clinical improvement and reported high levels of satisfaction at a minimum 10-year follow-up with low rates of reoperation.

Establishing patient-centered metrics for the knee injury and osteoarthritis outcome score following medial unicompartmental knee arthropalsty

BACKGROUND

This study aimed to determine the minimal clinically important difference (MCID) and the patient acceptable symptoms state (PASS) threshold for the knee injury and osteoarthritis outcome score (KOOS) pain subscore, KOOS physical short form (PS), and KOOS joint replacement (JR) following medial unicompartmental knee arthroplasty (mUKA).

METHODS

Prospectively collected data from 743 patients undergoing mUKA from a single academic institution from April 2015 through March 2020 were analyzed. Patient-reported outcome measures (PROMs) were collected both pre-operatively and 1-year post-operatively. Distribution-based and anchored-based approaches were used to estimate MCIDs and PASS, respectively. The optimal cut-off point and the percentage of patients who achieved PASS were also calculated.

RESULTS

MCID for KOOS-pain, KOOS-PS, and KOOS-JR following mUKA were calculated to be 7.6, 7.3, and 6.2, respectively. The PASS threshold for KOOS pain, PS, and JR were 77.8, 70.3, and 70.7, with 68%, 66%, and 64% of patients achieving satisfactory outcomes, respectively. Cut-off values for delta KOOS pain, PS, and JR were found to be 25.7, 14.3, and 20.7 with 73%, 69%, and 68% of patients achieving satisfactory outcomes, respectively.

CONCLUSION

The current study identified useful values for the MCID and PASS thresholds at 1 year following medial UKA of KOOS pain, KOOS PS, and KOOS JR scores. These values may be used as targets for surgeons when evaluating PROMS using KOOS to determine whether patients have achieved successful outcomes after their surgical intervention. Potential uses include the integration of these values into predictive models to enhance shared decision-making and guide more informed decisions to optimize patient outcomes.

LEVEL OF EVIDENCE

III.

Functional Outcome Scores and Conversion to Total Hip Arthroplasty After Hip Arthroscopy for Femoroacetabular Impingement Syndrome in Patients With Tönnis Grade 1 Versus Grade 0 Arthritis: A Propensity-Matched Study at Minimum 10-Year Follow-up

BACKGROUND

Hip arthroscopy has become the mainstay surgical intervention for the treatment of femoroacetabular impingement syndrome (FAIS). However, postoperative outcomes and rates of secondary surgery are mixed in patients with differing levels of preoperative osteoarthritis (OA). Furthermore, there is a paucity of literature comparing patients with and without OA at long-term follow-up.

PURPOSE

To compare outcomes and rates of secondary surgery at minimum 10-year follow-up, including revision hip arthroscopy and conversion to total hip arthroplasty (THA), in patients with Tönnis grade 1 undergoing hip arthroscopy for FAIS compared with a propensity-matched control group of patients with Tönnis grade 0.

STUDY DESIGN

Cohort study; Level of evidence, 3.

METHODS

Patients who underwent primary hip arthroscopy for FAIS between January 2012 and February 2013 were identified. Patients with Tönnis grade 1 were propensity matched in a 1:2 ratio by age, sex, and body mass index (BMI) to patients with Tönnis grade 0. Patient-reported outcomes (PROs) were collected at varying timepoints including preoperatively and 1, 2, 5, and 10 years postoperatively and compared between the 2 cohorts. Rates of minimal clinically important difference (MCID) and Patient Acceptable Symptom State (PASS) achievement at 10 years were evaluated and compared between groups. Rates of secondary surgery including revision hip arthroscopy and conversion to total hip arthroplasty (THA) were evaluated. Gross survivorship between cohorts was evaluated using a Kaplan-Meier gross survivorship curve. A subanalysis was performed comparing patients with Tönnis grade 1 who converted to THA and those who did not.

RESULTS

A total of 31 patients with Tönnis grade 1 (age, 42.6 ± 9.0 years; BMI, 28.0 ± 6.3) were successfully matched to 62 patients with Tönnis grade 0 (age, 42.1 ± 8.5, P = .805; BMI, 26.1 ± 3.9, P = .117). Both the Tönnis grade 1 and Tönnis grade 0 groups demonstrated significant improvements regarding all PROs at minimum 10 years (P < .05 for all), except for the Hip Outcome Score Activities of Daily Living subscale (HOS-ADL) (P = .066) in the Tönnis grade 1 cohort. No significant difference (P > .05 for all) was noted between cohorts regarding any 10-year PRO. When the authors evaluated comparisons between preoperative and 1-, 2-, 5-, and 10-year PRO measures, significant differences were noted between cohorts regarding 2-year HOS-ADL (P = .021), Hip Outcome Score Sports-Specific subscale (P = .016), and modified Harris Hip Score (P = .026); otherwise, differences did not reach significance. High rates of 10-year MCID and PASS achievement were seen, with no significant differences between groups. Patients with Tönnis grade 1 had significantly higher rates of conversion to THA compared with patients who had Tönnis grade 0 (25.8% vs 4.8%; P = .006). Patients with Tönnis grade 1 had significantly lower gross survivorship compared with those who had Tönnis grade 0 (71.0% vs 85.5%, respectively; P = .04).

CONCLUSION

Hip arthroscopy confers comparable postoperative clinical improvements to patients who have FAIS with and without mild OA; however, the benefits among patients with mild OA may be less durable. Patients with Tönnis grade 1 had significantly higher conversion to THA and reduced gross survivorship compared with patients with no evidence of preoperative OA, suggesting that patients with evidence of OA may need to be cautioned on the higher rate of conversion surgery.

Identification of Potentially High-risk Patients on the Basis of PROMs in a Certified Centre for Joint Replacement (EndoProthetikZentrum) Using the Example of Primary Knee Arthroplasty

BACKGROUND

The subjective evaluation of the patient's state of health with the help of Patient-reported Outcome Measurements (PROMs) provides valuable information for assessing the treatment outcome and for treatment planning. However, the use of PROMs in the field of arthroplasty is not mandatory, so that there is a lack of standardised recording and interpretation. The present study aims to identify patients, who have not achieved the intended treatment goals with regard to pain, function and quality of life after total knee arthroplasty, more easily in the future on the basis of postoperative PROMs.

MATERIAL AND METHODS

Data collection (for 3-month postoperative follow-up) included a standardised clinical follow-up (NU) and a questionnaire of different PROMs (Oxford Knee Score [OKS], OKS Pain Score [OKSS] and EndoCert Risk Score [ERS]). During the specialist follow-up examination, it was decided whether further medical therapy had to be initiated. Accordingly, patients were grouped into four post-treatment categories (NU not required/further diagnostics/new prescription/revision required).

RESULTS

For individual scores and questions, there were significant differences between the respective groups of consequences resulting from the follow-up examination. The OKS, OKS Pain Score and the ERS are suitable for detecting thresholds to determine the need for a follow-up examination. The postoperative thresholds of the scores are 24 for the OKS total score, 52 for the OKS pain score and 4 for the ERS pain intensity score.

CONCLUSION

In the initial three months after knee arthroplasty, certain PROMs are suitable for identifying patients for whom further diagnostics and therapy are indicated. In particular, the OKS and the pain intensity score of the ERS are suitable for detecting a potentially unfavourable development in rehabilitation after total knee arthroplasty.

Net Promoter Score: a prospective, single-centre observational study assessing if a single question determined treatment success after primary or revision hip arthroplasty

BACKGROUND

Our study aimed to identify the relationship between treatment outcome assessed by patient-reported outcomes (PROMs) and satisfaction measured by calculation of the Net Promoter Score (NPS), which identifies promoters, following total hip arthroplasty (THA). The aim was to evaluate this association separately in primary and revision THA and to determine thresholds based on PROMs that identify detractors of the surgical procedure or the centre.

METHODS

A total of 1,243 patients who underwent primary or revision THA at our hospital were asked to complete questionnaires of the Oxford Hip Score (OHS), Euroquol-5D (EQ-5D) and information on pain intensity preoperatively, three and 12 months after surgery. Postoperatively, the patients were additionally asked about their satisfaction with the procedure and the hospital by using three different NPS questions. The association between PROMs and NPS was evaluated based on group comparisons of primary or revision THA and receiver operating characteristics analysis (ROC) to determine threshold values.

RESULTS

At 12 months the NPS of all three questions were invariably linked to treatment outcome in patients after primary THA and patients with a single revision. In these two treatment groups, promoters always showed significantly better PROM scores than detractors. The NPS score was always higher in the primary group in comparison to the single revision group, e.g. 66.4% would undergo the procedure again in the first group, while only 33.0% would opt for this in the latter group. The high thresholds for the PROMs at 12 months, that were calculated by ROC analysis to identify promoter/detractors, indicate that patients` satisfaction required very good joint function and pain relief. However, the NPS was not a suitable tool to identify patients who need further care in an early phase after surgery.

CONCLUSIONS

With NPS already a single question or a single parameter provides the desired information regarding patient satisfaction and also treatment success.

TRIAL REGISTRATION

The study was approved by the Ethics Committee at the Medical Faculty of the University Rostock: "Ethikkommission an der Medizinischen Fakultät der Universität Rostock", Address: St.-Georg Str. 108 18055 Rostock, Germany, reference number: A2015-0055.

How Much Perioperative Pain and Dysfunction Underlie the HOOS JR and KOOS JR?

BACKGROUND

The Hip Disability and Osteoarthritis Outcome Score Joint Replacement (HOOS JR) and Knee Injury and Osteoarthritis Outcome Score Joint Replacement (KOOS JR) scores represent pain and dysfunction as a single number ranging from 0 (extreme pain and dysfunction) to 100 (no pain or functional limitations). However, scores between 0 and 100 lack a simple interpretation because they reflect varying combinations of pain levels and dysfunction. Given that most adverse events and improvement occur within the first 90 days after surgery, a deeper understanding of the level of pain and dysfunction may reveal missed opportunities for patient care.

QUESTIONS/PURPOSES

(1) What does a given preoperative or postoperative HOOS JR and KOOS JR score indicate about pain and ability to perform daily activities? (2) How much of a change in score (that is, delta) is needed to indicate significant improvement in pain control and daily functioning?

METHODS

The Michigan Arthroplasty Registry Collaborative Quality Initiative contains more than 95% of THAs and TKAs performed in Michigan. Between January 2017 and March 2019, 84,175 people in the registry underwent primary THA or TKA and were potentially eligible for this retrospective, comparative study of the first 90 postoperative days. Eighty-four percent (70,608 of 84,175) were excluded because their surgeons did not attain a target survey collection proportion of 70% and another 6% (5042) were missing covariate information or surveys, leaving 10% (8525) for analysis. The mean age and percentage of women were 65 ± 11 years and 55% (2060 of 3716), respectively, for patients undergoing THA and 67 ± 9 years and 61% (2936 of 4809), respectively, for those undergoing TKA. There were no clinically meaningful differences between patients who were analyzed and those who were excluded except for lower representation of non-White patients in the analyzed group. For interpretation, patient responses to Question 7 (pain) and Question 6 (function) from the Patient-Reported Outcomes Measurement Information System global items (PROMIS-10) were dichotomized into "much pain" (rating of pain 4 to 10 of 10) versus "less pain" (rating of ≤ 3) and "good function" (able to perform most activities) versus "poor function" (not able to perform most activities) and combined into four pain-function categories. We examined the mean preoperative and postoperative HOOS JR and KOOS JR scores for each pain-function category, adjusted for patient characteristics. We calculated the size of the delta associated with an increase to a more favorable category postoperatively (versus staying in the same or worse category) via multivariable logistic regression that controlled for patient characteristics.

RESULTS

Patients in the least favorable "much pain, poor function" category preoperatively had adjusted mean scores of 40 (95% confidence interval 39 to 41) for both the HOOS JR and KOOS JR. Those with mixed levels of pain and function had mean scores between 46 and 55. Those in the most favorable "less pain, good function" category had means of 60 (95% CI 58 to 62) and 59 (95% CI 58 to 61) for the HOOS JR and KOOS JR, respectively. The adjusted delta to achieve a pain level of ≤ 3 or the ability to perform most activities was 30 (95% CI 26 to 36) on the HOOS JR and 27 (95% CI 22 to 29) on the KOOS JR scales.

CONCLUSION

These adjusted means of the HOOS JR and KOOS JR provide context for understanding the levels of pain and dysfunction for individuals as well for patients reported in other studies. Potential quality improvement efforts could include tracking the proportion of patients with THA or TKA who achieved a sufficient delta to attain pain levels of ≤ 3 or the ability to perform most activities. Future studies are needed to understand pain and function represented by the HOOS JR and KOOS JR at 1 to 2 years, how these may differ by patient subgroups, and whether scores can be improved through quality improvement efforts.

LEVEL OF EVIDENCE

Level III, therapeutic study.

Effect of Differing Orientation and Magnitude of Femoral Torsion on Outcomes and Achievement of the MCID and PASS at 5 Years After Hip Arthroscopy for Femoroacetabular Impingement Syndrome

BACKGROUND

Femoral torsion measurements and outcomes are variable throughout the literature and have focused on short-term follow-up. However, there is a paucity of literature investigating clinically meaningful outcomes at midterm follow-up after hip arthroscopy for femoroacetabular impingement syndrome (FAIS).

PURPOSE

To quantify femoral version using computed tomography imaging in patients with FAIS and to explore the relationship between version abnormalities and 5-year outcomes after hip arthroscopy.

STUDY DESIGN

Cohort study; Level of evidence, 3.

METHODS

Patients who underwent primary hip arthroscopy for FAIS between January 2012 and November 2017 were identified. Patients were included if they had 5-year follow-up with completion of ≥1 patient-reported outcome (PRO) scores and excluded if they had Tönnis grade >1, revision hip surgery, a concomitant hip procedure, a developmental disorder, or a lateral center-edge angle <20°. Torsion groups were defined as severe retrotorsion (<0°), moderate retrotorsion (0.1°-5°), normal torsion (5.1°-20°), moderate antetorsion (20.1°-25°), and severe antetorsion (>25.1°) based on computed tomography measurements. Patient characteristics were analyzed among the torsion cohorts, as were preoperative and 5-year PROs: Hip Outcome Score-Activities of Daily Living, Hip Outcome Score-Sports Subscale, modified Harris Hip Score, international Hip Outcome Tool, visual analog scale for pain, and visual analog scale for satisfaction. Achievement rates of cohort-specific thresholds for the minimal clinically important difference and Patient Acceptable Symptom State were calculated and compared among cohorts.

RESULTS

A total of 362 patients (244 female, 118 male; mean ± SD age, 33.1 ± 11.5 years; body mass index, 26.9 ± 17.8) met inclusion/exclusion criteria and were analyzed at a final mean follow-up of 64.3 ± 9.4 months (range, 53.5-115.5 months). Mean femoral torsion was 12.8°± 9.2°. The number of patients within each group was 20 for severe retrotorsion (torsion, -6.3°± 4.9°), 45 for moderate retrotorsion (2.7°± 1.3°), 219 for normal torsion (12.2°± 4.1°), 39 for moderate antetorsion (21.9°± 1.3°), and 39 for severe antetorsion (29.0°± 4.2°). No significant differences in age, body mass index, sex, smoking status, workers' compensation, psychiatric history, back pain, or physical activity were found among the torsional groups. All groups demonstrated significant improvements at 5 years postoperatively (P < .01 for all). All torsion subgroups demonstrated similar pre- to postoperative changes in PROs (P≥ .515) and PRO values at 5-year follow-up (P≥ .098). There were no significant differences in the achievement of the minimal clinically important difference (P≥ .422) or Patient Acceptable Symptom State (P≥ .161) for any of the PROs among the torsion groups.

CONCLUSION

The orientation and severity of femoral torsion at the time of hip arthroscopy for FAIS in this study's cohort did not affect the propensity for clinically meaningful outcome improvement at midterm follow-up.

Patient Acceptable Symptom State Versus Latent Class Analysis Outcome Classification: A Comparative Longitudinal Study of Knee Arthroplasty

OBJECTIVE

To determine whether Patient Acceptable Symptom State (PASS), a single-item deterministic binary measure of pain and function outcome satisfaction, leads to better differentiation of outcome classification versus latent class analysis probability-based outcome subgroups 1 year after knee arthroplasty (KA).

METHODS

We used data from Knee Arthroplasty Skills Training for Pain (KASTPain), a 1-year no-effect multicenter randomized clinical trial of participants with KA, along with prior work that developed and externally validated good and poor outcome trajectories. Confirmatory latent class analyses were conducted on 2 exemplar outcome measures (Euroquol visual analog scale single-item self-rated health and 4-item pain ratings) and compared with PASS scores. Separation of trajectories were used to compare good and poor latent class self-rated health/4-item pain trajectories and PASS score trajectories.

RESULTS

Prevalence rates for poor outcomes were 10% for self-rated health and 20% for 4-item pain and PASS. Probabilistic latent class-derived classifications of self-rated health and 4-item pain outcomes outperformed PASS in separating growth trajectories. The effect size point estimates for 12-month 4-item pain scale score separation was approximately 3 times larger for latent class analyses as compared with PASS.

CONCLUSIONS

When used for outcome classification, observed PASS scores consistently underperform relative to probabilistic latent class-derived subgroups of pain and self-rated health outcome. PASS is a weak substitute for probabilistic classification of other patient-reported outcome measures of KA outcome. Clinicians and researchers should rely on latent class analyses over PASS to differentiate between outcome subgroups after KA.

Infographic: Total hip arthroplasty in early osteoarthritis

Cite this article: Bone Joint Res 2023;12(5):309–310.

Interpretation Threshold Values for the Oxford Hip Score in Patients Undergoing Total Hip Arthroplasty: Advancing Their Clinical Use

BACKGROUND

Patient-reported outcome measures such as the Oxford Hip Score (OHS) can capture patient-centered perspectives on outcomes after total hip arthroplasty (THA). The OHS assesses hip pain and functional limitations, but defining interpretation threshold values for the OHS is warranted so that numerical OHS values can be translated into whether patients have experienced clinically meaningful changes. Therefore, we determined the minimal important change (MIC), patient acceptable symptom state (PASS), and treatment failure (TF) threshold values for the OHS at 12 and 24-month follow-up in patients undergoing THA.

METHODS

This cohort study used data from patients undergoing THA at 1 public hospital between July 2016 and April 2021. At 12 and 24 months postoperatively, patients provided responses for the OHS and for 3 anchor questions about whether they had experienced changes in hip pain and function, whether they considered their symptom state to be satisfactory, and if it was not satisfactory, whether they considered the treatment to have failed. The anchor-based adjusted predictive modeling method was used to determine interpretation threshold values. Baseline dependency was evaluated using a new item-split method. Nonparametric bootstrapping was used to determine 95% confidence intervals (CIs).

RESULTS

Complete data were obtained for 706 (69%) of 1,027 and 728 (66%) of 1,101 patients at 12 and 24 months postoperatively, respectively. These patients had a median age of 70 years, and 55% to 56% were female. Adjusted OHS MIC values were 6.3 (CI, 4.6 to 8.1) and 5.2 (CI, 3.6 to 6.7), adjusted OHS PASS values were 30.6 (CI, 29.0 to 32.2) and 30.5 (CI, 29.3 to 31.8), and adjusted OHS TF values were 25.5 (CI, 22.9 to 27.7) and 27.0 (CI, 25.2 to 28.8) at 12 and 24 months postoperatively, respectively. MIC values were 5.4 (CI, 2.1 to 9.1) and 5.0 (CI, 1.9 to 8.7) higher at 12 and 24 months, respectively, in patients with a more severe preoperative state.

CONCLUSIONS

The established interpretation threshold values advance the interpretation and clinical use of the OHS, and may prove especially beneficial for registry-based evaluations of treatment quality.

LEVEL OF EVIDENCE

Prognostic Level IV. See Instructions for Authors for a complete description of levels of evidence.

The Strongest Oxford Knee Score Predictors of Subsequent Revision are 'Overall Pain,' 'Limping when Walking,' and 'Knee Giving Way'

BACKGROUND

The Oxford Knee Score (OKS) is used to measure knee arthroplasty outcomes, however, it is unclear which questions are more relevant. Our aims were to: 1) identify which OKS question(s) were the strongest predictors of subsequent revision and 2) compare predictive ability of the 'pain' and 'function' domains.

PATIENTS AND METHODS

All primary total (TKAs) and unicompartmental knee arthroplasties (UKAs) in the New Zealand Joint Registry between 1999 and 2019 with an OKS at six months (TKA n=27,708, UKA n=8,415), five years (TKA n=11,519, UKA n=3,365) or ten years (TKA n=6,311, UKA n=1,744) were included. Prediction models were assessed using logistic regressions and receiver operating characteristic analyses.

RESULTS

A reduced model with three questions ('overall pain,' 'limping when walking,' 'knee giving way') showed better diagnostic ability than full OKS for predicting UKA revision at six months (area under the curve (AUC): 0.80 vs. 0.78; P<0.01) and five years (0.81 vs. 0.77; P=0.02), and comparable diagnostic ability for predicting TKA revision at all timepoints (6 months, 0.77 vs. 0.76; 5 years, 0.78 vs. 0.75; 10 years, 0.76 vs. 0.73; all not significant (NS)), and UKA revision at 10 years (0.80 vs. 0.77; NS). The pain domain had better diagnostic ability for predicting subsequent revision for both procedures at five and ten years.

CONCLUSION

Questions on 'overall pain', 'limping when walking', and 'knee 'giving way' were the strongest predictors of subsequent revision. Attention to low scores from these questions during follow-up may allow for prompt identification of patients most at risk of revision.

The patient acceptable symptom state for the knee society score, oxford knee score and short form-36 following unicompartmental knee arthroplasty

PURPOSE

The patient acceptable symptom state (PASS) is a target value on a patient-reported outcome measures (PROM) scale beyond which patients deem themselves to have attained an acceptable outcome. This study aimed to define the PASS thresholds for generic and knee-specific PROMs at 2 years after unicompartmental knee arthroplasty (UKA).

METHODS

Prospectively collected data of 955 patients who underwent UKA for medial osteoarthritis at a single institution was reviewed. Patients were assessed preoperatively and 2 years postoperatively using the Knee Society Knee Score (KSKS), Function Score (KSFS), Oxford Knee Score (OKS), SF-36 Physical Component Score (PCS) and Mental Component Score (MCS). Responses to an anchor question assessing patients' overall rating of treatment results were dichotomized and used to determine if PASS was achieved. PASS thresholds for each PROM were selected based on the Youden index on a receiver operating characteristics (ROC) curve. Sensitivity analyses were performed for different subgroups (by age, gender, BMI), baseline score tertiles and an alternate definition of PASS.

RESULTS

In total, 92.7% reported their current state as acceptable. The areas under the curve (AUC) for ROCs were 0.72-0.83, except for the SF-36 PCS (AUC 0.64), indicating good discriminative accuracy of the other PROMs. PASS thresholds were 85.5 for KSKS, 77.5 for KSFS, 41.5 for OKS, 49.9 for SF-36 PCS and 54.6 for SF-36 MCS. Sensitivity analyses revealed that the thresholds were robust. Patients who attained a PASS were at least 4-5 times more likely to be satisfied and have expectations fulfilled.

CONCLUSION

PASS thresholds can be used to define treatment success in future outcome studies. At the individual level, they provide clinically relevant benchmarks for surgeons when assessing postoperative recovery.

LEVEL OF EVIDENCE

III.

Preoperative Pain Catastrophizing Prior to Total Knee Arthroplasty is Associated With Worse Preoperative Symptoms and More Clinical Improvement: A Prospective Comparative Study

BACKGROUND

Total knee arthroplasty (TKA) is a reliable procedure for end-stage osteoarthritis with excellent long-term survivorship, but approximately 15% of patients are not satisfied. Pain catastrophizing (PC) has been proposed as a potential cause but current evidence is limited to smaller studies with short-term follow-up. Our goal was to assess outcomes following TKA in a large cohort with and without PC.

METHODS

A prospective comparative study was performed with patients undergoing unilateral primary TKA between 2019 and 2021 with 2-year follow-up. All patients completed a PC Scale questionnaire preoperatively and a score of minimum 30 was considered PC. Outcomes consisted of Knee injury and Osteoarthritis Outcome Score-Physical Function Shortform (KOOS-PS), Oxford Knee Score (OKS), numeric rating scale Pain, and aseptic revisions. Ultimately, 301 patients were included (mean age 69 years [range, 30-92 years], with 60.8% women). Forty four patients (14.6%) had PC.

RESULTS

Preoperatively, PC patients had inferior KOOS-PS, inferior OKS, and more pain than non-PC patients (all P < .001). PC patients had more improvement from preoperatively to 6 months postoperatively for KOOS-PS, OKS, and pain (all P < .05) and to 12 months for KOOS-PS and OKS (both P < .005). Similarly, PC patients had more improvement from preoperative to 24 months for OKS (P = .003). At 24 months, however, PC patients reported more pain than non-PC patients. There was no difference in revision rates (P = .192).

CONCLUSION

Patients who had PC reported worse function and pain preoperatively but had more improvement to 6 months and 12 months postoperatively. At 24 months, similar subjective function was noted, although PC patients reported more pain.

How does the use of quantified gap-balancing affect component positioning and limb alignment in robotic total knee arthroplasty using functional alignment philosophy? A comparison of two robotic platforms

PURPOSE

This study aimed to compare the effect of an image-based (MAKO) system using a gap-balancing technique with an imageless (OMNIbot) robotic tool utilising a femur-first measured resection technique.

METHODS

A retrospective cohort study was performed on patients undergoing primary TKA with a functional alignment philosophy performed by a single surgeon using either the MAKO or OMNIbot robotic systems. In all cases, the surgeon's goal was to create a balanced knee and correct sagittal deformity (eliminate any fixed flexion deformity). Intra-operative data and patient-reported outcomes (PROMS) were compared.

RESULTS

A total of 207 MAKO TKA and 298 OMNIbot TKAs were analysed. MAKO TKA patients were younger (67 vs 69, p=0.002) than OMNIbot patients. There were no other demographic or pre-operative alignment differences. Regarding implant positioning, in MAKO TKAs the femoral component was more externally rotated in relation to the posterior condylar axis (2.3° vs 0.1°, p<0.001), had less valgus femoral cuts (1.6° vs 2.7° valgus, p<0.001) and more varus tibial cuts (2.4° vs 1.9° varus, p<0.001), and had more bone resected compared to OMNIbot TKAs. OMNIbot cases were more likely to require tibial re-cuts than MAKO (15% vs 2%, p<0.001). There were no differences in femur recut rates, soft tissue releases, or rate of achieving target coronal and sagittal leg alignment between robotic systems. A subgroup analysis of 100 MAKO and 100 OMNIbot propensity-matched TKAs with 12-month follow-up showed no significant difference in OKS (42 vs 43, p=0.7) or OKS PASS scores (83% vs 91%, p=0.1). MAKO TKAs reported significantly better symptoms according to their KOOS symptoms score than patients that had OMNIbot TKAs (87 vs 82, p=0.02) with a higher proportion of KOOS PASS rates, at a slightly longer follow-up time (20 months vs 14 months, p<0.001). There were no other differences in PROMS.

CONCLUSION

A gap-balanced technique with an image-based robotic system (MAKO) results in different implant positioning and bone resection and reduces tibial recuts compared to a femur-first measured resection technique with an imageless robotic system (OMNIbot). Both systems achieve equal coronal and sagittal deformity correction and good patient outcomes at short-term follow-ups irrespective of these differences.

Patient acceptable symptom state (PASS): thresholds for the EQ-5D-5L and Oxford hip and knee scores for patients with total hip and knee replacement

PURPOSE

To define patient acceptable symptom state (PASS) cut-off values for the EQ-5D-5L and Oxford hip (OHS) and knee (OKS) scores 6 and 12 months after total hip (THR) or knee (TKR) replacement. To compare PASS cut-off values for the EQ-5D-5L scored using: (1) the Canadian value set, (2) the crosswalk value set, and (3) the equal weighted Level Sum Score (LSS).

METHODS

We mailed questionnaires to consecutive patients following surgeon referral for primary THR or TKR and at 6 and 12 months post-surgery. Patient reported outcome measures (PROMs) were the EQ-5D-5L, the OHS, and OKS. We assessed PASS cut-off values for PROMs using percentile and ROC methods, with the Youden Index.

RESULTS

Five hundred forty-two surgical patients (mean age, 64 years, 57% female, 49% THR) completed baseline and 12-month questionnaires. 89% of THR and 81% of TKR patients rated PASS as acceptable at 12 months. PASS cut-off values for THR for the EQ-5D-5L (Canadian) were 0.85 (percentile) and 0.84 (Youden) at 12 months. Cut-off values were similar for the LSS (0.85 and 0.85) and lower for the crosswalk value set (0.74 and 0.73), respectively. EQ-5D-5L cut-off values for TKR were Canadian, 0.77 (Percentile) and 0.78 (Youden), LSS, 0.75 and 0.80, and crosswalk, 0.67 and 0.74, respectively. Cut-off values 6 and 12 months post-surgery ranged from 38 to 39 for the OHS, and 28 to 36 for the OKS (range 0 worst to 48 best).

CONCLUSION

PASS cut-off values for the EQ-5D-5L and Oxford scores varied, not only between methods and timing of assessment, but also by different EQ-5D-5L value sets, which vary between countries. Because of this variation, PASS cut-off values are not necessarily generalizable to other populations of TJR patients. We advise caution in interpreting PROMs when using EQ-5D-5L PASS cut-off values developed in different countries. A standardization of methods is needed before published cut-off values can be used with confidence in other populations.

Partial versus total knee arthroplasty for isolated antero-medial osteoarthritis - An analysis of PROMs and satisfaction

AIM

This study aimed to compare the patient-reported functional outcomes and patient satisfaction after medial Unicompartmental Knee Arthroplasty (UKA) versus Total Knee Arthroplasty (TKA), performed for anteromedial osteoarthritis (AMOA) of the knee in patients from an Indian population, at a minimum 3-year follow-up.

METHODS

This is a prospective matched cohort study (1:2 ratio). One hundred and one UKA cases were matched to 206 TKA cases by propensity score matching for age, body mass index (BMI), gender distribution, and the Charlson Comorbidity Index (CCI). The primary outcome (Oxford knee score, OKS) was assessed at a 3-year follow-up, along with secondary outcomes (Western Ontario and McMaster Universities Osteoarthritis Index [WOMAC] Score, Forgotten Joint Score (FJS), Anterior Knee Pain (Kujala) score, patient satisfaction, and revision rate at the final follow-up).

RESULTS

The UKA group was superior to the TKA group in patient-reported functional outcomes based on the OKS (p = 0.004). Using the FJS score, UKA was more likely to be a forgotten joint compared to TKA (p < 0.001). However, differences in the OKS and FJS did not meet the reported minimal clinically important difference (MCID) thresholds. Quality of life (EuroQol-5D VAS scale) was found to be significantly higher in the UKA group (p < 0.001). Patients in the UKA group were more likely to be very satisfied (75.2%) versus the TKA group (62.1%, p = 0.023).

CONCLUSION

For AMOA, UKA was associated with improved patient satisfaction compared to TKA. Although patient-reported outcome measures were statistically in favour of UKA over TKA, the differences were not clinically significant. Multicenter and randomized studies comparing the two procedures are warranted.

EVIDENCE

Level-II Therapeutic.

Harmonising knee pain patient-reported outcomes: a systematic literature review and meta-analysis of Patient Acceptable Symptom State (PASS) and individual participant data (IPD)

OBJECTIVE

In order to facilitate data pooling between studies, we explored harmonisation of patient-reported outcome measures (PROMs) in people with knee pain due to osteoarthritis or knee trauma, using the Patient Acceptable Symptom State scores (PASS) as a criterion.

METHODS

We undertook a systematic literature review (SLR) of PASS scores, and performed individual participant data (IPD) analysis of score distributions from concurrently completed PROM pairs. Numerical rating scales (NRS), visual analogue scales, KOOS and WOMAC pain questionnaires were standardised to 0 to 100 (worst) scales. Meta-regression explored associations of PASS. Bland Altman plots compared PROM scores within individuals using IPD from WebEx, KICK, MenTOR and NEKO studies.

RESULTS

SLR identified 18 studies reporting PASS in people with knee pain. Pooled standardised PASS was 27 (95% CI: 21 to 35; n = 6,339). PASS was statistically similar for each standardised PROM. Lower PASS was associated with lower baseline pain (β = 0.49, P = 0.01) and longer time from treatment initiation (Q = 6.35, P = 0.04). PASS scores were lowest in ligament rupture (12, 95% CI: 11 to 13), but similar between knee osteoarthritis (31, 95% CI: 26 to 36) and meniscal tear (27, 95% CI: 20 to 35). In IPD, standardised PROMs each revealed similar group mean scores, but scores within individuals diverged between PROMs (LoA between -7 to -38 and +25 to 52).

CONCLUSION

Different standardised PROMs give similar PASS thresholds in group data. PASS thresholds may be affected more by patient and treatment characteristics than between PROMs. However, different PROMs give divergent scores within individuals, possibly reflecting different experiences of pain.

A radiological index that influences the outcome following patellofemoral joint arthroplasty: the anterior trochlea offset ratio

PURPOSE

Although largely successful, patellofemoral joint arthroplasty (PFA) has a less than satisfactory outcome in some patients. It was hypothesized that certain factors can be identified on radiological review that correlate with poor patient reported outcomes following PFA.

METHODS

A retrospective cohort review of 369 patients undergoing PFA at our institution between 2005 and 2018 identified 43 "poor outcome" patients with an Oxford Knee Score (OKS) of less than 20 at 2 years follow up. These cases were matched by sex and age with 43 "good outcome" patients who had an OKS above 40 at 2 years post-op. Multiple radiological measurements were performed including anterior trochlea offset ratio (ATOR), component flexion/extension, component varus/valgus, component to bone width ratio and retinacular index. The OKS PROM was the primary outcome of the study. Stepwise logistic regression was performed to analyze the differences in radiological indices between the two groups.

RESULTS

Intraclass correlation coefficients for inter-observer and intra-observer reliability were 0.90-0.98 for all indices measured. The only index demonstrating statistical significance between the groups was the ATOR (p = 0.003). The good outcome group had a mean ATOR of 0.19 whereas the poor outcome group had a mean ATOR of 0.24.

CONCLUSIONS

Lower ATOR on radiological review was strongly associated with improved outcomes following PFA. The surgeon should therefore take particular care to prevent increasing the anterior offset of the trochlea component when performing PFA.

LEVEL OF EVIDENCE

Retrospective cohort study, Level III.

Defining the Minimal Clinically Important Difference and Patient Acceptable Symptom State After Endoscopic Gluteus Medius or Minimus Repair With or Without Labral Treatment and Routine Capsular Closure at Minimum 5-Year Follow-up

BACKGROUND

There is a paucity of information in the literature on midterm outcomes of endoscopic gluteus medius and/or minimus repair with concomitant labral treatment using only modern surgical techniques.

PURPOSE

To define the minimal clinically important difference (MCID) and Patient Acceptable Symptom State (PASS) at a minimum of 5 years postoperatively for patients undergoing endoscopic hip abductor repair with routine capsular closure.

STUDY DESIGN

Case series; Level of evidence, 4.

METHODS

Consecutive patients who underwent primary endoscopic repair of gluteus medius and/or minimus tears between January 2012 and December 2015 by the senior author were eligible for inclusion. Patient-reported outcome scores were assessed preoperatively and at 5 years postoperatively: Hip Outcome Score-Activities of Daily Living (HOS-ADL), HOS-Sport Specific (HOS-SS), modified Harris Hip Score (mHHS), 12-item International Hip Outcome Tool (iHOT-12), and visual analog scale (VAS) for pain. The MCID was uniquely calculated using the distribution method, and the PASS was determined via the anchor-based method utilizing receiver operating characteristic curves and Youden index.

RESULTS

A total of 46 patients were included in the study. The majority were female (87.0%), with a mean ± standard deviation age of 59.1 ± 8.9 years and body mass index of 27.3 ± 6.9. Significant postoperative improvements (P < .001) in each of the 5 patient-reported outcomes were observed at 5 years postoperatively. The MCID threshold values were calculated as follows: HOS-ADL, 11.5; HOS-SS, 15.1; mHHS, 13.3; iHOT-12, 11.8; and VAS, 15.8. The PASS thresholds were calculated as follows: HOS-ADL, 75.7; HOS-SS, 79.7; mHHS, 81.2; and iHOT-12, 60.8. A majority of patients achieved a clinically significant outcome, with 96.2% of patients reaching a threshold score for the MCID or PASS for at least 1 patient-reported outcome.

CONCLUSION

Endoscopic hip abductor repair with concomitant arthroscopic labral treatment has a high rate of achievement of clinically significant outcomes and survivorship at a minimum 5-year follow-up. We defined the MCID for the HOS-ADL, HOS-SS, mHHS, iHOT-12, and VAS outcome scores to be 11.5, 15.1, 13.3, 11.8, and 15.8, respectively. The PASS threshold scores for the HOS-ADL, HOS-SS, mHHS and iHOT-12 scores of 75.7, 79.7, 81.2, and 60.8, respectively. Future researchers and clinicians can use the MCID and PASS values established in this study to better evaluate mid-term outcomes of patients undergoing hip abductor repair.

Identification of Potential High-Risk Patients on the Basis of PROMs in a Certified Centre for Joint Replacement (EndoProthetikZentrum) Using the Example of Hip Arthroplasty

BACKGROUND

In addition to clinical parameters, the subjective assessment by the patient to evaluate the operative outcome of an arthroplasty is becoming increasingly important. Questionnaires are used to identify patients who have not achieved the treatment goal at an early stage so that further interventions can be indicated.

MATERIAL AND METHODS

A questionnaire consisting of different PROMs was completed pre- and 3 months postoperatively by patients who had been treated with a hip arthroplasty. A standardised follow-up examination of these patients was carried out 12 to 16 weeks postoperatively, after which it was determined whether further therapy was necessary to achieve the treatment goal. Different consequences were defined for this.

RESULTS

Significant differences were found between the groups of consequences of follow-up examinations over both time points, but also when postoperative scores were considered exclusively. Furthermore, the correlations for the postoperative scores and some consequences of the clinical follow-up for the Oxford Hip Score (OHS), the OHS functional score and the Euroquol-5D show moderate effects. Thus, the collection of these postoperative scores is sufficient to identify potential high risk patients. Based on a receiver operating characteristic (ROC) analysis, threshold values could be determined for these scores, for which a follow-up examination is recommended.

CONCLUSION

Patients who could not achieve functional improvement, pain reduction and improvement in quality of life after implantation of a total hip replacement must be identified at an early stage. The results of our study show that with the help of the Oxford Hip Score and Euroquol-5D, which are answered by the patients three months postoperatively, such high risk patients can be identified. This finding is an added value for the further development of the EndoCert certification system and holistic quality assurance in arthroplasties, while the personnel and time effort remain manageable.

20-year hip survivorship and patient-reported outcome measures after transpositional osteotomy of the acetabulum for dysplastic hips

AIMS

Although periacetabular osteotomies are widely used for the treatment of symptomatic dysplastic hips, long-term surgical outcomes and patient-reported outcome measures (PROMs) are still unclear. Accordingly, we assessed hip survival and PROMs at 20 years after transpositional osteotomy of the acetabulum (TOA).

METHODS

A total of 172 hips in 159 patients who underwent TOA were followed up at a mean of 21.02 years (16.6 to 24.6) postoperatively. Kaplan-Meier analysis was used to assess survivorship with an endpoint of total hip arthroplasty (THA). PROMs included the visual analogue scale (VAS) Satisfaction, VAS Pain, Oxford Hip Score (OHS), and Forgotten Joint Score-12 (FJS-12). Thresholds for favourable outcomes for OHS (≥ 42) and FJS-12 (≥ 51) were obtained using the receiver operating characteristic curve with VAS Satisfaction ≥ 50 and VAS Pain < 20 as anchors.

RESULTS

THA was performed on 37 hips (21.5%) by the latest follow-up. Kaplan-Meier analysis indicated that the hip survival rate at 20 years was 79.7% (95% confidence interval (CI) 73.7 to 86.3). Multivariate analysis showed that preoperative Tönnis grade significantly influenced hip survival. Tönnis grades 0, 1, and 2 were associated with 20-year survival rates of 93.3% (95% CI 84.8 to 100), 86.7% (95% CI 79.8 to 94.3), and 54.8% (95% CI 41.5 to 72.3), respectively. More than 60% of the patients exhibited favourable PROMs. An advanced Tönnis grade at the latest follow-up and a higher BMI were both significantly associated with unfavourable OHS, but not with other PROMs.

CONCLUSION

This study demonstrated the durability of TOA for hips with Tönnis grades 0 to 1 at 20 years. While the presence of advanced osteoarthritis and higher BMI was associated with lower hip functions (OHS), it was not necessarily associated with worse patient satisfaction and joint awareness. Cite this article: Bone Joint J 2022;104-B(7):767-774.

Robotic-assisted surgery and kinematic alignment in total knee arthroplasty (RASKAL study): a protocol of a national registry-nested, multicentre, 2×2 factorial randomised trial assessing clinical, intraoperative, functional, radiographic and survivorship outcomes

INTRODUCTION

Robot-assisted surgery (RAS) and kinematic alignment (KA) are being increasingly adopted to improve patient outcomes in total knee arthroplasty (TKA). There is uncertainty around the individual or combined effect of these concepts compared with computer-assisted surgery (CAS) and mechanical alignment (MA), respectively. This study aims to assess the effectiveness of RAS, KA or both to improve clinical outcomes, functional measures, radiographic precision and prosthetic survivorship when compared with current gold standards of surgical care.

METHODS AND ANALYSIS

A national registry-nested, multicentre, double-blinded, 2×2 factorial, randomised trial will be undertaken with 300 patients undergoing primary unilateral TKA performed by 15 surgeons. The primary outcome will be the between-group differences in postoperative change over 2 years in the mean Knee injury and Osteoarthritis Outcome Score (KOOS-12), comparing first, RAS to CAS as its control, and second, KA to MA as its control. Secondary outcomes will include other knee-specific and general health patient-reported outcome measures (PROMs), intraoperative pressure loads as a measure of soft tissue balance, 6-month postoperative functional outcomes, radiological precision using CT imaging, complications and long-term prosthetic survivorship. The contribution of each patient's unique coronal plane alignment of the knee phenotype to primary and secondary PROMs will be investigated. OMERACT-OARSI criteria and Patient Acceptable Symptom State outcome score thresholds for the KOOS-12 and Oxford Knee Score will be used in secondary analyses. Primary intention-to-treat and secondary per-protocol analyses will be performed. Statistical analysis will include a generalised linear mixed model for repeated measures for continuous KOOS-12 scores. Kaplan-Meier estimates with adjusted HRs of implant survivorship will be calculated.

ETHICS AND DISSEMINATION

Ethics approval was obtained from Sydney Local Health District-Royal Prince Alfred Hospital (Approval X20-0494 and 2020/ETH02896 10.24/DEC20). Results will be submitted for publication in a peer-reviewed journal and presented in national, state and international meetings.

TRIAL REGISTRATION NUMBER

ACTRN12621000205831.

Electrochemically applied hydroxyapatite on the cementless porous surface of Bi-Metric stems reduces early migration and has a lasting effect : an efficacy trial of a randomized five-year follow-up radiostereometric study

AIMS

BoneMaster is a thin electrochemically applied hydroxyapatite (HA) coating for orthopaedic implants that is quickly resorbed during osseointegration. Early stabilization is a surrogacy marker of good survival of femoral stems. The hypothesis of this study was that a BoneMaster coating yields a fast early and lasting fixation of stems.

METHODS

A total of 53 patients were randomized to be treated using Bi-Metric cementless femoral stems with either only a porous titanium plasma-sprayed coating (P group) or a porous titanium plasma-sprayed coating with an additional BoneMaster coating (PBM group). The patients were examined with radiostereometry until five years after surgery.

RESULTS

At three months, the mean total translation (TT) was 0.95 mm (95% confidence interval (CI) 0.68 to 1.22) in the P group and 0.57 mm (95% CI 0.31 to 0.83) in the PBM group (p = 0.047). From two to five years, the TT increased by a mean of 0.14 mm (95% CI 0.03 to 0.25) more in the P group than in the PBM group (p = 0.021). In osteopenic patients (n = 20), the mean TT after three months was 1.61 mm (95% CI 1.03 to 2.20) in the P group and 0.73 mm (95% CI 0.25 to 1.21) in the PBM group (p = 0.023). After 60 months, the mean TT in osteopenic patients was 1.87 mm (95% CI 1.24 to 2.50) in the P group and 0.82 mm (95% CI 0.30 to 1.33) in the PBM group (p = 0.011).

CONCLUSION

There was less early and midterm migration of cementless stems with BoneMaster coating compared with those with only a porous titanium plasma-sprayed coating. Although a BoneMaster coating seems to be important for stem fixation, especially in osteopenic patients, further research is warranted. Cite this article: Bone Joint J 2022;104-B(6):647-656.

Estimation of Patient Acceptable Symptom State (PASS) and Treatment Failure (TF) Threshold Values for the Achilles Tendon Total Rupture Score (ATRS) at 6 Months, 1 Year, and 2 Years After Acute Achilles Tendon Rupture

Interpretation of the Achilles tendon Total Rupture Score (ATRS) is challenging because limited knowledge exists about at which score the patients consider the outcome of treatment as satisfactory. The aims of the study were (1) to describe the proportion of patients who find their symptom levels to be satisfactory, to reflect treatment failure or neither after acute Achilles tendon rupture (ATR), and (2) to estimate the Patient Acceptable Symptom State (PASS) and the Treatment Failure (TF) threshold values for the ATRS at 6 months, 1 year, and 2 years after ATR. The study was based on data extracted from the nationwide Danish Achilles tendon Database which includes patients treated operatively or nonoperatively after ATR. The PASS and TF threshold values for ATRS were estimated using the adjusted predictive modeling method. One hundred and sixty-six patients were included at 6 months, 248 patients at 1 year, and 287 patients at 2 years after ATR. The proportion of patients who considered their symptom level to be satisfactory was 61% at 6 months, 50% at 1 year, and 66% at 2 years, while 5% at 6 months, 11% at 1 year, and 10% at 2 years considered their symptom level to reflect treatment failure. The PASS threshold value for ATRS (95% confidence interval) was 49 (46-52) at 6 months, 57 (54-60) at 1 year, and 52 (49-55) at 2 years. The TF threshold value for ATRS was 30 (23-36) at 6 months, 33 (26-40) at 1 year, and 35 (29-39) at 2 years. The calculated PASS and TF threshold values can help interpret the outcome of ATR when measured with the ATRS. About 50% to 66% of the patients had a satisfactory symptom level after ATR.

Defining Clinically Meaningful Thresholds for Patient-Reported Outcomes in Knee Arthroplasty

BACKGROUND

For primary knee arthroplasties, clinically meaningful thresholds of patient-reported outcomes that associate with patient satisfaction have not been defined appropriately.

METHODS

In this retrospective study of 26,720 primary total knee replacements registered in the Dutch Arthroplasty Register (2016-2018), receiver operating curve analysis was used to define minimal clinically important changes (MCICs) and patient acceptable symptom states (PASSs) with the anchor satisfaction. Patient-reported outcome measures were pain, European Quality of Life 5 Dimensions, Knee disability and Osteoarthritis Outcome Score, and Oxford Knee Score (OKS). Independent analyses were performed for groups, which showed statistically significant interactions with the (change in) score to achieve satisfaction in logistic regression.

RESULTS

In this cohort, 84.9% completed the anchor questions, of whom 71.3% with a satisfaction score ≥8. Good discriminative abilities (area under the receiving operator curve >0.8) for PASS were achieved by OKS ≥38.5, pain in activity ≤2.5, Knee disability and Osteoarthritis Outcome Score ≤33, and Quality of Life-Index ≥0.813. Discriminative abilities for MCIC were not good. If assessed per baseline tercile, discrimination improved (area under the receiving operator curve >0.8) and yielded different MCICs per preoperative tercile (preoperative OKS ≤19: MCIC ≥19.5; pre-OKS 20-27: MCIC ≥14.5; pre-OKS ≥28: MCIC ≥8.5). For MCIC, the tercile method produced an 11% improved accuracy compared to one threshold for every patient. For the PASS scores, tercile-specific did not improve the accuracy of predicting satisfaction. Demographics were not clinically relevant in determining thresholds.

CONCLUSION

Estimating the likelihood of satisfaction with surgery is critical in shared decision-making. Patients with more preoperative symptom severity require larger changes to report satisfaction. Both in the clinic and in science, such differences must be considered when predictions of satisfaction are attempted.

Postoperative pain as a risk factor for stiff knee following total knee arthroplasty and excellent patientreported outcomes after manipulation under anesthesia

BACKGROUND AND PURPOSE

Manipulation under anesthesia (MUA) is the first-choice treatment for stiffness following total knee arthroplasty (TKA) unresponsive to pain management and physiotherapy. Some of the predisposing factors and patient-reported outcome measures (PROMs) following MUA remain poorly studied. We retrospectively investigated the etiological risk factors and the outcomes of MUA.

PATIENTS AND METHODS

391 TKA patients from a randomized trial comparing the use of a tourniquet and anesthesia (spinal or general) were analyzed, and patients needing MUA were identified (MUA group). We evaluated in-hospital opioid consumption, Oxford Knee Score (OKS), range of motion (ROM), and pain assessed by the Brief Pain Inventory-short form with a 1-year follow-up.

RESULTS

39 (10%) MUA patients were identified. The MUA patients were younger (60 years vs. 64 years, difference -4, 95% CI -6 to -1) and had higher postoperative oxycodone consumption (66 mg vs. 51 mg, median difference 11, CI 1-22) than the no-MUA patients. The proportion of MUA patients who contacted the emergency department within 3 months because of pain was larger than that of non-MUA patients (41% vs. 12%, OR 5, CI 3-10). At the 1-year follow-up, the ROM was improved by 39° following MUA, but the total ROM was worse in the MUA group (115° vs. 124°, p < 0.001). No difference was found in the OKS between the MUA and no-MUA patients.

INTERPRETATION

Higher postoperative pain seems to predict MUA risk. MUA performed 3 months postoperatively offers substantial ROM improvement and comparable PROMs to no-MUA patients 1 year after TKA.

Defining the Patient Acceptable Symptom State for the HOOS JR and KOOS JR After Primary Total Joint Arthroplasty

BACKGROUND

It is essential to quantify an acceptable outcome after total joint arthroplasty (TJA) in order to understand quality of care. The purpose of this study was to define patient acceptable symptom state (PASS) thresholds for the Knee injury and Osteoarthritis Outcome Score, Joint Replacement (KOOS JR) and the Hip disability and Osteoarthritis Outcome Score, Joint Replacement (HOOS JR) after TJA.

METHODS

A receiver operating characteristic (ROC) curve analysis, leveraging 2-year satisfaction of "moderate improvement" or better as the anchor, was used to establish PASS thresholds among 5,216 patients who underwent primary total hip arthroplasty and 4,036 who underwent primary total knee arthroplasty from 2007 to 2012 with use of an institutional registry. Changes in PASS thresholds were explored by stratifying and recalculating these thresholds by age at the time of surgery (<70 or ≥70 years of age), sex (men or women), body mass index (BMI; <30 or ≥30 kg/m2), and baseline Short Form-36 (SF-36) physical and mental component scores (<50 or ≥50).

RESULTS

The HOOS JR PASS threshold was 76.7 (area under the ROC curve [AUC] = 0.91), which was achieved by 4,334 patients (83.1%). The KOOS JR PASS threshold was 63.7 (AUC = 0.89), which was achieved by 3,461 patients (85.8%). Covariate stratification demonstrated that PASS thresholds were higher in men compared with women, and in those with higher preoperative SF-36 physical and mental scores (≥50) compared with lower SF-36 scores (<50). Results differed between instruments for BMI and age: higher BMI was associated with a lower PASS threshold for the HOOS JR but a higher PASS threshold for the KOOS JR. The HOOS JR PASS threshold was higher in patients who were <70 years of age compared with those who were ≥70 years of age, but was equivalent for the KOOS JR.

CONCLUSIONS

The PASS thresholds for the HOOS JR and KOOS JR at 2 years after TJA were 76.7 and 63.7, respectively. The PASS thresholds were associated with certain preoperative covariates, suggesting that an acceptable symptom state after TJA is influenced by patient-specific factors.

LEVEL OF EVIDENCE

Prognostic Level IV. See Instructions for Authors for a complete description of levels of evidence.

Adjusting for Variation in Patient-Reported Outcome Measures Is Needed to Improve Care After Total Knee Arthroplasty

INTRODUCTION

Limited quantitative information exists about the patient and surgeon factors driving variation in patient-reported outcome measure (PROM) scores, limiting the use of these data in understanding and improving quality. The overall goal of this study was to learn how to adjust PROM scores to enable both individual and group quality improvement.

METHODS

Observational study in which preoperative Oxford Knee Score (OKS) and Patient Reported Outcomes Measurement System (PROMIS)-10 measures were prospectively obtained through patient survey from 1,173 of 1,435 possible patients before total knee arthroplasty and from 810 of the 1,173 patients at 12 months postoperatively (response rates = 81.7% and 69.0%). Regression analyses identified the relative contribution of patient and surgeon risk factors to OKS change from baseline to 12 months. Variation in patient scores and surgeon performance was described and quantified. Adjusted outcomes were used to calculate an observed and expected score for each surgeon.

RESULTS

(1) Moderate variation was observed in pre-/post-OKS change among the surgeons (n = 16, mean change = 15.5 ± 2.2, range = 12.1-21.1). Forty-five percent of the variance in OKS change was explained by the factors included in our model. (2) Patient preoperative OKS and PROMIS physical score, race, and BMI were markedly associated with change in OKS, but other patient factors, surgeon volume, and years of experience were not. (3) Eight surgeons had observed scores greater than expected after adjustment, providing an opportunity to learn what strategies were associated with better outcomes.

DISCUSSION

Traditional age/sex adjustment of patient mix would have had no effect on mean PROM scores by surgeon. An adjustment model that includes the factors found to be markedly associated with outcomes will allow care systems to identify individual surgeon care management strategies potentially important for improving patient outcomes.

Higher rates of surgical and medical complications and mortality following TKA in patients aged ≥ 80 years: a systematic review of comparative studies

The purpose of this systematic review was to synthesize studies published since the last systematic review in 2015 that compare outcomes of primary total knee arthroplasty (TKA) in older patients (≥ 80 years) and in younger patients (< 80 years), in terms of complication rates and mortality.

An electronic literature search was conducted using PubMed, Embase®, and Cochrane Register. Studies were included if they compared outcomes of primary TKA for osteoarthritis in patients aged 80 years and over to patients aged under 80 years, in terms of complication rates, mortality, or patient-reported outcomes (PROs).

Thirteen studies were eligible. Surgical complications in older patients ranged from 0.6–21.1%, while in younger patients they ranged from 0.3–14.6%. Wound complications in older patients ranged from 0.5–20%, while in younger patients they ranged from 0.8–22.0%. Medical complications (cardiac, respiratory, thromboembolic) in older patients ranged from 0.4–17.3%, while in younger patients they ranged from 0.2–11.5%.

Mortality within 90 days in older patients ranged between 0–2%, while in younger patients it ranged between 0.0–0.03%.

Compared to younger patients, older patients have higher rates of surgical and medical complications, as well as higher mortality following TKA. The literature also reports greater length of stay for older patients, but inconsistent findings regarding PROs. The present findings provide surgeons and older patients with clearer updated evidence, to make informed decisions regarding TKA, considering the risks and benefits within this age group. Patients aged over 80 years should therefore not be excluded from consideration for primary TKA based on age alone.

Cite this article: EFORT Open Rev 2021;6:1052-1062. DOI: 10.1302/2058-5241.6.200150

Clinical Outcome Comparison between Staged -Bilateral Versus Simultaneous Bilateral Total Knee Replacements

BACKGROUND

This retrospective study aimed to compare the clinical outcomes of patients with staged and simultaneous bilateral total knee arthroplasty (TKA).

METHODS

The present study included 100 patients with a mean age of 62±3.72 years from 2014 to 2017. Among them, 51 and 49 patients underwent simultaneous and staged bilateral TKA, respectively. The two groups were compared regarding the range of motion (ROM), Oxford Knee Score (OKS), Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) improvement, and Medical Outcomes Study 36-item Short-Form Health Survey (SF-36) scores. The mean follow-up duration was 24 months (range: 12-36 months).

RESULTS

According to the results obtained from the SF-36 questionnaire (possessing eight different factors of quality of life), there was no significant difference between the two groups. Furthermore, the OKSs were 39.98±1.52 and 38.68±2.55 in the simultaneous and staged groups, respectively. Moreover, the WOMAC improvement scores were obtained at 84.15±2.2 and 83.26±2.6 in the simultaneous and staged groups, respectively. The final knee ROM was acceptable without a significant difference between the two groups.

CONCLUSION

Substantial controversy about the complications, functional, and clinical outcomes has negatively affected the decision of the surgeons on conducting bilateral sequential TKA. This clinical assessment revealed that all determinants, including OKS, WOMAC, SF-36, ROM, postoperative bleeding, and hospitalization duration exhibited almost the same improvement in both groups. According to this study, no statistically significant difference exists in both procedures.

Use of a Tourniquet and Spinal Anesthesia Increases Satisfactory Outcomes After Total Knee Arthroplasty: A Randomized Study

BACKGROUND

Total knee arthroplasty (TKA) is usually performed successfully with or without a tourniquet and under spinal anesthesia (SA) or general anesthesia (GA). However, 10% to 34% of patients experience dissatisfaction and pain after TKA. We aimed to compare the effects of tourniquet use and SA or GA on TKA outcomes.

METHODS

We randomly assigned 404 patients to 4 study groups: SA without a tourniquet (NT/SA), SA with a tourniquet (T/SA), GA without a tourniquet (NT/GA), and GA with a tourniquet (T/GA). The primary outcome was the change in the Oxford Knee Score (OKS) at 1 year postoperatively. Secondary outcomes included a satisfactory TKA outcome assessed using the OKS minimal important change (MIC) and OKS patient acceptable symptom state (PASS), adverse events, and quality of life using the 15-dimensional health-related quality of life tool.

RESULTS

At 1 year, the OKS was obtained for 381 patients. In the 2-group comparisons, the tourniquet did not affect the OKS improvement. The SA group had more substantial improvement in the OKS than the GA group (16.21 compared with 14.08 a mean difference of 2.13; 95% confidence interval [CI], 0.55 to 3.71; p = 0.008). In the 4-group comparisons, the T/SA group had more substantial improvements in the OKS than the NT/GA group (16.87 compared with 13.65, a mean difference of 3.2; 95% CI, 0.28 to 6.17; p = 0.026). The SA group reached the OKS MIC more frequently than the GA group (91.7% compared with 81.7%; odds ratio [OR] = 2.49 [95% CI, 1.32 to 4.69]; p = 0.005). The SA group also reached the OKS PASS more frequently than the GA group (86.0% compared with 75.7%; OR = 2.00 [95% CI, 1.18 to 3.39]; p = 0.010). The T/SA group had significantly more patients reaching the OKS MIC than the NT/GA group (95.7% compared with 79.6%; p = 0.005) and more patients reaching the OKS PASS than the NT/GA group (92.6% compared with 74.5%; p = 0.004). No differences were seen with respect to adverse events in any comparisons.

CONCLUSIONS

The tourniquet had no detrimental effects on the outcomes of TKA. SA had a positive effect on the OKS. The use of SA combined with a tourniquet resulted in the best improvement in OKS and the highest proportion of satisfactory outcomes with TKA.

LEVEL OF EVIDENCE

Therapeutic Level I. See Instructions for Authors for a complete description of levels of evidence.

Collection and Reporting of Patient-reported Outcome Measures in Arthroplasty Registries: Multinational Survey and Recommendations

BACKGROUND

Patient-reported outcome measures (PROMs) are validated questionnaires that are completed by patients. Arthroplasty registries vary in PROM collection and use. Current information about registry collection and use of PROMs is important to help improve methods of PROM data analysis, reporting, comparison, and use toward improving clinical practice.

QUESTIONS/PURPOSES

To characterize PROM collection and use by registries, we asked: (1) What is the current practice of PROM collection by arthroplasty registries that are current or former members of the International Society of Arthroplasty Registries, and are there sufficient similarities in PROM collection between registries to enable useful international comparisons that could inform the improvement of arthroplasty care? (2) How do registries differ in PROM administration and demographic, clinical, and comorbidity index variables collected for case-mix adjustment in data analysis and reporting? (3) What quality assurance methods are used for PROMs, and how are PROM results reported and used by registries? (4) What recommendations to arthroplasty registries may improve PROM reporting and facilitate international comparisons?

METHODS

An electronic survey was developed with questions about registry structure and collection, analysis, reporting, and use of PROM data and distributed to directors or senior administrators of 39 arthroplasty registries that were current or former members of the International Society of Arthroplasty Registries. In all, 64% (25 of 39) of registries responded and completed the survey. Missing responses from incomplete surveys were captured by contacting the registries, and up to three reminder emails were sent to nonresponding registries. Recommendations about PROM collection were drafted, revised, and approved by the International Society of Arthroplasty Registries PROMs Working Group members.

RESULTS

Of the 25 registries that completed the survey, 15 collected generic PROMs, most frequently the EuroQol-5 Dimension survey; 16 collected joint-specific PROMs, most frequently the Knee Injury and Osteoarthritis Outcome Score and Hip Disability and Osteoarthritis Outcome Score; and 11 registries collected a satisfaction item. Most registries administered PROM questionnaires within 3 months before and 1 year after surgery. All 16 registries that collected PROM data collected patient age, sex or gender, BMI, indication for the primary arthroplasty, reason for revision arthroplasty, and a comorbidity index, most often the American Society of Anesthesiologists classification. All 16 registries performed regular auditing and reporting of data quality, and most registries reported PROM results to hospitals and linked PROM data to other data sets such as hospital, medication, billing, and emergency care databases. Recommendations for transparent reporting of PROMs were grouped into four categories: demographic and clinical, survey administration, data analysis, and results.

CONCLUSION

Although registries differed in PROM collection and use, there were sufficient similarities that may enable useful data comparisons. The International Society of Arthroplasty Registries PROMs Working Group recommendations identify issues that may be important to most registries such as the need to make decisions about survey times and collection methods, as well as how to select generic and joint-specific surveys, handle missing data and attrition, report data, and ensure representativeness of the sample.

CLINICAL RELEVANCE

By collecting PROMs, registries can provide patient-centered data to surgeons, hospitals, and national entities to improve arthroplasty care.

Determining Clinically Meaningful Thresholds for the Nonarthritic Hip Score in Patients Undergoing Arthroscopy for Femoroacetabular Impingement Syndrome

PURPOSE

The purpose of this study was to improve the interpretability of the Nonarthritic Hip Score (NAHS) by determining the minimal clinically important difference (MCID), patient acceptable symptomatic state (PASS), and substantial clinical benefit (SCB) after hip arthroscopy for femoroacetabular impingement. The secondary aim was to identify variables associated with achievement of the thresholds.

METHODS

Patients who underwent hip arthroscopy for femoroacetabular impingement and completed postoperative questionnaires between August 2019 and March 2020 were included. Patients were excluded if they underwent previous ipsilateral hip surgery, underwent gluteus medius repair, or had a previous hip condition. The MCID, PASS, and SCB thresholds were calculated for the NAHS at minimum 1-, 2-, and 5-year follow-up. Distribution- and anchor-based methods with receiver operating characteristic analysis were used to determine the thresholds. Multivariate logistic regression was performed to determine predictors of achieving the MCID and PASS.

RESULTS

The study included 343 hips with an average follow-up period of 48 months. On the basis of the distribution-based approach, the MCID was 8.7 using a method in which the standard deviation of the baseline score was divided by 2. By use of a method in which the standard deviation of the change score was divided by 2, MCID scores of 9.1, 8.3, and 12.6 resulted at a minimum of 1, 2, and 5 years, respectively. The PASS thresholds for these time points were 81.9, 85.6, and 81.9. The absolute SCB thresholds were 91.9, 94.4, and 93.1 and the change score thresholds were 30.6, 24.4, and 29.3 for a minimum of 1, 2, and 5 years, respectively. The preoperative NAHS was positively associated with achievement of the PASS and inversely related to achievement of the MCID.

CONCLUSIONS

This study provides important clinical thresholds for the NAHS. These thresholds were determined for minimum 1-, 2-, and 5-year time points. The MCID was determined as 8.7, the PASS ranged between 81.9 and 85.6, and the absolute SCB value ranged from 91.9 to 94.4. The preoperative NAHS was found to be positively associated with achievement of the PASS and inversely related to achievement of the MCID.

LEVEL OF EVIDENCE

Level IV, retrospective case series.

Minimally Invasive Inlay Prosthesis Unicompartmental Knee Arthroplasty for the Treatment of Unicompartmental Osteoarthritis: A Prospective Observational Cohort Study with Minimum 2-Year Outcomes and up to 14-Year Survival

There are limited medium-term outcome data available for the Repicci II device in unicompartmental knee arthroplasty (UKA). The purpose of this study was to report the medium-term (minimum 2 years) patient-reported outcomes and long-term (up to 14 years) procedure survival in a consecutive series of patients undergoing an inlay prosthesis UKA (Repicci II) at an independent orthopaedic clinic. Patients presenting with medially localized unicompartmental knee osteoarthritis and meeting the criteria appropriate for UKA were recruited to a clinical patient registry at the time of presentation. A cemented unicompartmental prosthesis (Repicci II) was implanted using minimally invasive techniques with rapid postoperative mobilization. Patients were asked to complete patient-reported outcomes preoperatively and annually postoperatively. A procedure list was cross-matched with the Australian Orthopaedic Association National Joint Replacement Registry (AOANJRR), and an analysis of procedure survival was performed with comparison to the national data for UKA. Data from a cohort of 661 primary medial compartment UKA procedures performed in 551 patients over a 15-year period were extracted from the clinical patient registry. Significant improvements were maintained in general health, disease symptoms, pain, and function at an average follow-up of 9 years compared with preoperative data. Threshold analysis revealed that >65% of patients exceeded Patient Acceptable Symptom State at the latest follow-up, with >80% within or exceeding age-matched norms for general health. Cumulative revision rate was significantly lower than that reported for UKA in the AOANJRR at up to 13 years follow-up. This series represents a lower cumulative revision rate than previously reported, with >65% of patients reporting satisfactory functional outcomes at an average of 9 years from surgery. Surgical options for treating unicompartmental knee osteoarthritis could include UKA as a viable alternative; however, clear definitions of procedure success and its overall cost-benefit ratio in the context of ongoing management of knee osteoarthritis remain to be elucidated.

Disappointing Relationship between Functional Performance and Patient Satisfaction of UKA Patients: A Cross Sectional Study

BACKGROUND

Following a Unicompartmental knee arthroplasty (UKA) satisfaction is often conflated with functional outcome. Recent studies have shown that satisfaction is not linked to functional outcome. The research questions were: (1) what is the relationship between satisfaction and functional performance and quality of life (absolute and gain values) after UKA? And (2) what is the level of satisfaction, function, and quality of life after UKA?

HYPOTHESIS

There is a poor relationship between functional performance and patient satisfaction following UKA.

METHODS

This was a retrospective study using a locally held arthroplasty register to identify patients who had undergone UKA between 2004 and 2017. Patient reported outcome measures (PROMs) were collected prospectively and included EQ-5D, Oxford Knee Score (OKS) and satisfaction score (based on a visual analogue score with 0 being worst and 100 being best). Patients with a complete set of pre-operative and 2-year post-operative outcome scores were included. Patients who subsequently underwent revision surgery were excluded. 1638 patients were identified, of which 896 were eligible for inclusion. The average age was 66.7 years old, with 46.3% of patients being female.

RESULTS

There was a moderate to strong correlation between the absolute or relative values for OKS and the patient satisfaction following UKA (r=0.705 and r=0.522, respectively). The average pre-operative scores improved from a median of 23 (IQR 18-28) to 43 (IQR 35-46) (p<0.001) and from a median of 0.62 (IQR 0.186-0.691) to 0.85 (IQR 0.691 - 1) (p<0.001) for OKS and EQ-5D, respectively. In terms of satisfaction with outcome, 82.6% of patients were very satisfied and 4.4% were dissatisfied (scoring ≥80% and <50%, respectively). At 2 years, the PASS was met or surpassed by 73.1% and 54.9% (OKS and EQ-5D, respectively). The MCID was met or surpassed by 93% and 78% (OKS and EQ-5D, respectively).

DISCUSSION/CONCLUSION

UKA is a successful procedure generating high levels of patient function and satisfaction. Because patients' OKS and EQ-5D scores may be influenced by comorbidities, those scores are of disappointing predictive value in estimating patient satisfaction, and therefore should not be used as a surrogate to determine the success of the UKA procedure.

LEVEL OF EVIDENCE

III; Restrospective cohort study.

Oxford Knee Score and EQ-5d poorly predict patient's satisfaction following mechanically aligned total knee replacement: A cross-sectional study

BACKGROUND

Patient satisfaction is increasingly used to measure the success of arthroplasty. Satisfaction with the outcome of a total knee replacement (TKR) is traditionally thought to be associated with improvements in functional status and quality of life measures. This study aims to answer the following questions: 1. What is the level of patient satisfaction, improvement in knee function and patient quality of life associated with mechanically aligned TKR? 2. What is the relationship between OKS, EQ-5d scores and 'outcome satisfaction'?

HYPOTHESIS

TKR is associated with a significant improvement in function, satisfaction and quality of life and that there is a strong correlation between OKS, EQ-5d and 'outcome satisfaction'.

METHOD

Five thousand eight hundred and ninety six patients underwent primary TKR between January 2010 and December 2017 and had complete preoperative and 2-year follow-up data for OKS, EQ-5d and satisfaction scores. Outcomes data were collected prospectively and recorded on our institutional database. Minimal clinically important difference (MCID) and the Patient acceptable symptomatic state (PASS) were calculated for OKS and EQ-5d, the association between OKS, EQ-5d and 'outcome satisfaction' was measured using regression analysis.

RESULTS

The median 2-year 'outcome satisfaction' score was 90/100 with 79% of patients reporting excellent satisfaction (≥80/100) and 93.4% of patients satisfied (≥50/100). Postoperatively, median scores were 39 for OKS and 0.8 for EQ-5d. The mean increase in scores was 15.85 for OKS and 0.32 for EQ-5d. Satisfaction showed moderate positive correlation with postoperative OKS (r=0.69) and EQ-5D (0.58) scores, but weaker correlation with the change in OKS (r=0.57) and EQ-5d (r=0.32) scores from preoperative levels.

DISCUSSION/CONCLUSION

Mechanically aligned TKR is overall a successful operation responsible of fair rate of patient satisfaction. OKS and EQ-5d are imperfect predictors for satisfaction as they are significantly influenced by patients' comorbidities. This should be taken into account when evaluating the success of an operation.

LEVEL OF EVIDENCE

IIc; observational study (based on prospectively collected data from an institutional registry).

Which Oxford Knee Score level represents a satisfactory symptom state after undergoing a total knee replacement?

Background and purpose - Meaningful interpretation of postoperative Oxford Knee Score (OKS) levels is challenging. We established Patient Acceptable Symptoms State (PASS) and Treatment Failure (TF) values for the OKS in patients undergoing primary total knee replacement (TKR) in Denmark.Patients and methods - Data from patients undergoing primary TKR between February 2015 and January 2019 was extracted from the arthroplasty registry at the Copenhagen University Hospital, Hvidovre in Denmark. Data included 3, 12, and 24 months postoperative responses to the OKS and 2 anchor questions asking whether they considered their symptom state to be satisfactory, and if not, whether they considered the treatment to have failed. PASS and TF threshold values were calculated using the adjusted predictive modeling method. Non-parametric bootstrapping was used to derive 95% confidence intervals (CI).Results - Complete 3, 12, and 24 months postoperative data was obtained for 187 of 209 (89%), 884 of 915 (97%), and 575 of 586 (98%) patients, with median ages from 68 to 70 years (59 to 64% female). 72%, 77%, and 79% considered as having satisfactory symptoms, while 6%, 11%, and 11% considered the treatment to have failed, at 3, 12, and 24 months postoperatively, respectively. OKS PASS values (CI) were 27 (26-28), 30 (29-31), and 30 (29-31) at 3, 12, and 24 months postoperatively. TF values were 27 (26-28) and 27 (26-29) at 12 and 24 months postoperatively.Interpretation - The OKS PASS values can be used to guide the interpretation of TKR outcome and support quality assessment in institutional and national registries.

Categorization of changes in the Oxford Knee Score after total knee replacement: an interpretive tool developed from a data set of 46,094 replacements

OBJECTIVES

The objective of the study was to create an interpretive categorical classification for the transition in the Oxford Knee Score (OKS) change score (ΔOKS) using the anchor-based method.

STUDY DESIGN AND SETTING

Registry data from 46,094 total knee replacements from the year 2014/15, were accessed via the Health and Social Care Information Center official website. Data included preoperative and 6-month follow-up OKS and response to the transition anchor question. Categories were determined using Gaussian approximation probability and k-fold cross-validation.

RESULTS

Four categories were identified with the corresponding ΔOKS intervals: "1. much better" (≥16), "2. a little better" (7-15), "3. about the same" (1-6), and "4. much worse" (≤0) based on the anchor questions' original five categories. The mean 10-fold cross-validation error was 0.35 OKS points (95% confidence interval 0.12 to 0.63). Sensitivity ranged from 0.34 to 0.68; specificity ranged from 0.74 to 0.95.

CONCLUSION

We have categorized the change score into a clinically meaningful classification. We argue it should be an addition to the continuous OKS outcome to contextualize the results in a way more applicable to the shared decision-making process and for interpreting research results.