Validation of the English language Forgotten Joint Score-12 as an outcome measure for total hip and knee arthroplasty in a British population

Total knee arthroplasty using a cemented single-radius, condylar-stabilized design performed without posterior cruciate ligament sacrifice

Aims

Total knee arthroplasty (TKA) with a highly congruent condylar-stabilized (CS) articulation may be advantageous due to increased stability versus cruciate-retaining (CR) designs, while mitigating the limitations of a posterior-stabilized construct. The aim was to assess ten-year implant survival and functional outcomes of a cemented single-radius TKA with a CS insert, performed without posterior cruciate ligament sacrifice.

Methods

This retrospective cohort study included consecutive patients undergoing TKA at a specialist centre in the UK between November 2010 and December 2012. Data were collected using a bespoke electronic database and cross-referenced with national arthroplasty audit data, with variables including: preoperative characteristics, intraoperative factors, complications, and mortality status. Patient-reported outcome measures (PROMs) were collected by a specialist research team at ten years post-surgery. There were 536 TKAs, of which 308/536 (57.5%) were in female patients. The mean age was 69.0 years (95% CI 45.0 to 88.0), the mean BMI was 32.2 kg/m2 (95% CI 18.9 to 50.2), and 387/536 (72.2%) survived to ten years. There were four revisions (0.7%): two deep infections (requiring debridement and implant retention), one aseptic loosening, and one haemosiderosis.

Results

Kaplan-Meier analysis demonstrated no difference in implant survival according to sex, age, or obesity status. Ten-year PROMs were available for 196/387 (50.6%) surviving patients and were excellent: mean Oxford Knee Score 34.4 (95% CI 32.7 to 36.1); mean Forgotten Joint Score (FJS) 51.2 (95% CI 16.1 to 86.3); mean EuroQol five-dimension five-level questionnaire score 69.9 (95% CI 46.8 to 93.0); 141/196 (71.9%) achieved the 22-point FJS patient-acceptable symptom state (PASS); and 156/196 (79.6%) were "very satisfied or satisfied".

Conclusion

This is the only large study reporting ten-year implant survival and functional outcomes of TKA using a cemented single-radius design and with a CS tibial bearing construct. The findings of excellent implant survival, safety, and functional outcomes indicate that this combination is a safe and effective option in routine TKA. Further investigation of this single-radius design TKA with CS tibial bearings with well-matched patient study groups will allow further insight into the performance of these implants.

Comparison of robotic-assisted total knee arthroplasty: an updated systematic review and meta-analysis

This study was conducted to compare the changes in different clinical scores and imaging indexes of patients who underwent robot-assisted total knee arthroplasty (RA-TKA) and manual total knee arthroplasty (M-TKA). PubMed, Web of Science, Cochrane Library and Embase were searched according to PRISMA guidelines in June 2024. Search terms included "robot-assisted", "manual" and "total knee arthroplasty". Outcome indicators included American Knee Society Score (KSS), Western Ontario McMaster Universities Osteoarthritis Index (WOMAC), Oxford Knee Score (OKS), range of motion (ROM), Hospital for Special Surgery (HSS) score, Forgotten Joint Score (FJS), 36-Item Short Form Health Survey (SF-36), operation duration (min), intraoperative blood loss (ml), pain score, patient's satisfaction scores, hip-knee-ankle (HKA) angle, frontal femoral component angle, frontal tibia component angle, lateral femoral component angle and lateral tibia component angle. A total of 1,033 articles were obtained after removing duplicates, and 12 studies involving 2,863 patients (1,449 RA-TKAs and 1,414 M-TKAs) were finally meta-analyzed (22-32). The baseline data of both groups were similar in all results. Meta-analysis suggested a better performance of the RA-TKA group than the M-TKA group regarding the HKA angle. The manual TKA reduced the operation time and significantly improved the range of motion. The results of > 6 months follow-up showed that M-TKA was better than RA-TKA in terms of KSS score and WOMAC. Compared with M-TKA, RA-TKA can produce more accurate prosthetic alignment, but it does not lead to better clinical results. Orthopedic surgeons should choose between two surgical procedures according to their own experience and patients' characteristics.

Item-reduced Forgotten Joint Score provides adequate psychometric properties in ACLR patients

Purpose

The purpose of this study was to evaluate content validity, test-retest reliability, internal consistency, construct validity, responsiveness and floor/ceiling effects of Forgotten Joint Score (FJS) for assessing functions in activities of daily living (ADL) following anterior cruciate ligament reconstruction (ACLR) and perform an item reduction of FJS.

Methods

Swedish-speaking ACLR patients in one surgical clinic were eligible. Content validity was evaluated through patient responses and patient and expert clinician relevance ratings, omitting items with low relevance. Principal component factor analysis, Cronbach's ⍺, paired t test, correlations between FJS and Knee Injury and Osteoarthritis Outcome Score (KOOS), Cohen's d effect sizes (ESs) and standardized response mean (SRM) were used to evaluate internal consistency, test-retest reliability, construct validity and responsiveness. Floor/ceiling effects were calculated. FJS was expected to reveal one dominant factor, a Cronbach's ⍺ between 0.70 and 0.95, correlations >0.50 to all KOOS subscores, highest for ADL, moderate ES and SRM, floor/ceiling effects <15%.

Results

One hundred and seventy-six participants (103 for assessing internal consistency, construct validity, responsiveness and floor/ceiling effects; 73 for assessing test-retest reliability and content validity) were included. Item reduction yielded a nine-item FJS (FJS-9). FJS-12 and FJS-9 demonstrated sufficient content validity (95% confidence interval [CI], 2.5-3.1, respectively, 2.9-3.3). FJS-9 was found unidimensional, and FJS-12 was multidimensional. Cronbach's ⍺ was 0.94 for FJS, and the intraclass correlation coefficient > 0.90. FJS showed significant correlations >0.65 to all KOOS subscales, moderate ES and SRM > 0.50. No floor/ceiling effects were found.

Conclusion

FJS-9 demonstrated adequate validity for the evaluation of joint awareness in ACLR patients and can be a valuable tool to assess ADL and joint awareness.

Level of Eidence

Level III.

Robotic trials in arthroplasty surgery

Total hip and knee arthroplasty (THA, TKA) are largely successful procedures; however, both have variable outcomes, resulting in some patients being dissatisfied with the outcome. Surgeons are turning to technologies such as robotic-assisted surgery in an attempt to improve outcomes. Robust studies are needed to find out if these innovations are really benefitting patients. The Robotic Arthroplasty Clinical and Cost Effectiveness Randomised Controlled Trials (RACER) trials are multicentre, patient-blinded randomized controlled trials. The patients have primary osteoarthritis of the hip or knee. The operation is Mako-assisted THA or TKA and the control groups have operations using conventional instruments. The primary clinical outcome is the Forgotten Joint Score at 12 months, and there is a built-in analysis of cost-effectiveness. Secondary outcomes include early pain, the alignment of the components, and medium- to long-term outcomes. This annotation outlines the need to assess these technologies and discusses the design and challenges when conducting such trials, including surgical workflows, isolating the effect of the operation, blinding, and assessing the learning curve. Finally, the future of robotic surgery is discussed, including the need to contemporaneously introduce and evaluate such technologies.

Systematic evaluation of the degree of joint amnesia in patients after total hip arthroplasty with direct anterior approach (DAA) compared with posterior approach (PA)

OBJECTIVE

A comparative study of joint amnesia in patients undergoing total hip arthroplasty with the direct anterior approach and posterior approach was conducted through a comprehensive evaluation.

METHODS

The literature on joint amnesia in postoperative patients who underwent total hip arthroplasty by the direct anterior approach and the posterior approach was systematically searched in PubMed, Embase, Web of Science, Cochrane Library, CNKI, CBM, Wanfang, and VIP databases from the time of library construction until February 13, 2023. Meta-analysis was performed using RevMan 5.3 software after independent searching, screening of the literature, data extraction, and quality assessment of the included studies by two investigators in strict accordance with the guidelines for conducting meta-analyses.

RESULTS

A total of one RCT and six cohort studies were included in this meta-analysis. Meta-analysis results indicated that at 1 month postoperatively (MD = 2.08, 95% CI (0.20, 3.96), P = 0.03), 3 months (MD = 10.08, 95% CI (1.20, 18.96), P = 0.03), and 1 year (MD = 6.74, 95% CI (1.30, 12.19), P = 0.02), DAA total hip arthroplasty was associated with better FJS compared to PA at 1 year postoperatively. However, there was no statistical significance in FJS between the two groups at 5 years postoperatively (MD = 1.35, 95% CI (- 0.58, 3.28), P = 0.17).

CONCLUSION

Current evidence suggests that the degree of joint amnesia after THA for DAA was not found to be superior to that of PA. Further, these findings require confirmation by including a larger number of high-quality randomized controlled studies.

STUDY DESIGN

Systematic review; Level of evidence, 3.

Joint awareness among total hip arthroplasty patients operated through anterior approach versus posterior approach: a systematic review and meta-analysis

PURPOSE

The aim of this systematic review and meta-analysis was to compare joint awareness in patients who underwent total hip arthroplasty (THA) via the anterior approach (AA) versus the posterior approach (PA). The hypothesis was that patients who underwent THA via AA would have better forgetfulness of the artificial joint.

METHODS

A comprehensive search of major literature databases and bibliographic details was conducted to identify studies evaluating the forgotten joint score (FJS-12) in total hip arthroplasty (THA) patients operated through the anterior approach (AA) and posterior approach (PA). Out of 234 studies identified, seven studies met the inclusion criteria for review. The Newcastle-Ottawa Scale was used to evaluate the quality of evidence and the risk of bias in the included studies. The FJS-12 was evaluated at three months, one year, and beyond 2 years.

RESULTS

The mean FJS-12 at > 2 years was 82.03 in the AA group and 80.32 in the PA group. The forest plot analysis (n = 819 patients) revealed no significant difference in FJS-12 score between these two approaches (MD 2.13, 95% CI [- 1.17, 5.42], p = 0.21; I2 = 60%). However, the joint awareness was significantly lesser in the AA group at 3 months (MD 12.56, 95% CI [9.58, 15.54], p < 0.00001, I2 = 0%) and 1 year (MD 9.55, 95% CI [7.85, 11.24], p < 0.0001, I2 = 0%).

CONCLUSIONS

After analyzing the available literature, it was found that THA patients operated through the AA approach have significantly lower joint awareness than those operated through the PA approach in the first year of surgery. However, there is no significant difference in joint awareness between these two approaches after 2 years.

LEVEL OF EVIDENCE

III.

The Joint Awareness Score: A Shortened, Simplified, Improved Alternative to the Forgotten Joint Score

Background

The Forgotten Joint Score (FJS) is a 12-question patient-reported outcomes measure created to measure a patient's awareness of their artificial joint. The FJS has attained wide usage, though it is not without weaknesses. Our patients report that the semantics of the English translation are flawed and that the 5 answer options for each question are poorly differentiated. Additionally, the FJS will result in no score if 3 or more questions are unanswered. This prompted the development of an alternative patient-reported outcomes measure, the Joint Awareness Score (JAS), that builds upon the core concept of joint awareness underlying the FJS, but that is easier to understand and shorter to complete. We completed an exploratory, pilot study to evaluate this outcomes instrument. Our hypothesis is that the JAS will correlate strongly with the FJS and could be used as a substitute.

Methods

Knee arthroplasty patients in a prospective registry were administered the FJS and the JAS. Internal consistency and correlation were calculated with Cronbach's alpha and Pearson's correlation coefficient, respectively.

Results

This study included 174 patients. Cronbach's alpha for FJS was 0.97 for 6 months and 0.97 for 12 months, whereas JAS was 0.89 at 6 months and 0.85 at 12 months. Pearson correlation comparing FJS and JAS at 6 months was 0.88 (95% confidence interval: 0.83, 0.92) and 0.86 (95% confidence interval: 0.78, 0.92) at 12 months.

Conclusions

The Joint Awareness Score is a new patient-reported outcomes measure that is a substitute for the FJS, with half the number of questions, improved semantics, and simplified answers.

Nexus Evaluation Primary Trident II UNcemented shEll (NEPTUNE)

Aims

The primary aim of this study is to assess the survival of the uncemented hydroxyapatite (HA) coated Trident II acetabular component as part of a hybrid total hip arthroplasty (THA) using a cemented Exeter stem. The secondary aims are to assess the complications, joint-specific function, health-related quality of life, and radiological signs of loosening of the acetabular component.

Methods

A single-centre, prospective cohort study of 125 implants will be undertaken. Patients undergoing hybrid THA at the study centre will be recruited. Inclusion criteria are patients suitable for the use of the uncemented acetabular component, aged 18 to 75 years, willing and able to comply with the study protocol, and provide informed consent. Exclusion criteria includes patients not meeting study inclusion criteria, inadequate bone stock to support fixation of the prosthesis, a BMI > 40 kg/m2, or THA performed for pain relief in those with severely restricted mobility.

Results

Implant survival, complications, functional outcomes and radiological assessment up to ten years following index THA (one, two, five, seven, and ten years) will be performed. Functional assessment will include the Oxford Hip Score, Forgotten Joint Score, 12-Item Short Form Health Survey, EuroQol five-dimension health questionnaire, and pain and patient satisfaction. Radiological assessment with assess for acetabula lucent lines, lysis, and loosening according to DeLee and Charnley zones.

Conclusion

This study is part of a stepwise introduction of a new device to orthopaedic practice, and careful monitoring of implants should be carried out as part of the Beyond Compliance principles. The results of this study will provide functional, radiological, and survival data to either support the ongoing use of the HA acetabulum or highlight potential limitations of this new implant before wide adoption.

UK robotic arthroplasty clinical and cost effectiveness randomised controlled trial for hips (RACER-Hip): a study protocol

INTRODUCTION

The number of robotic-assisted hip replacement procedures has expanded globally with the intended aim of improving outcomes. Intraoperative robotic-arm systems add additional costs to total hip replacement (THR) surgery but may improve surgical precision and could contribute to diminished pain and improved function. Additionally, these systems may reduce the need for expensive revision surgery. Surgery with conventional instruments may be just as successful, quick and affordable. There is timely demand for a robust evaluation of this technology.

METHODS AND ANALYSIS

The Robotic Arthroplasty Clinical and cost Effectiveness Randomised controlled trial for Hips (RACER-Hip) is a multicentre (minimum of six UK sites), participant-assessor blinded, randomised controlled trial. 378 participants with hip osteoarthritis requiring THR will be randomised (1:1) to receive robotic-assisted THR, or THR using conventional surgical instruments. The primary outcome is the Forgotten Joint Score at 12 months post-randomisation; a patient-reported outcome measure assessing participants' awareness of their joint when undertaking daily activities. Secondary outcomes will be collected post-operatively (pain, blood loss and opioid usage) and at 3, 6, 12, 24 months, then 5 and 10 years postrandomisation (including function, pain, health-related quality of life, reoperations and satisfaction). Allocation concealment will be accomplished using a computer-based randomisation procedure on the day of surgery. Blinding methods include the use of sham incisions for marker clusters and blinded operation notes. The primary analysis will adhere to the intention-to-treat principle. Results will adhere to Consolidated Standards of Reporting Trials statements.

ETHICS AND DISSEMINATION

The trial was approved by an ethics committee (Solihull Research Ethics Committee, 30 June 2021, IRAS: 295831). Participants will provide informed consent before agreeing to participate. Results will be disseminated using peer-reviewed journal publications, presentations at international conferences and through the use of social media. We will develop plans to disseminate to patients and public with our patient partners.

TRIAL REGISTRATION NUMBER

ISRCTN13374625.

Cross-cultural adaptation, validity and reliability of the Arabic version of the Forgotten Joint Score for knee arthroplasty

PURPOSE

To evaluate the validity and reliability of the Arabic version of this questionnaire in Arabic patients who underwent total knee arthroplasty (TKA).

METHODS

The Arabic version of the English FJS (Ar-FJS) was modified according to cross-cultural adaptation best practices. The study included 111 patients who underwent TKA 1-5 years ago and completed the Ar-FJS. The reduced Western Ontario and McMaster Universities Osteoarthritis Index (rWOMAC) and 36-Item Short Form (SF-36) were used to assess the construct validity of the study. Fifty-two individuals took the Ar-FJS test twice to evaluate the test-retest reliability.

RESULTS

The reliability of the Ar-FJS demonstrated a Cronbach's α value of 0.940 and an intraclass correlation coefficient of 0.951. The ceiling effect of the Ar-FJS was 5.4% (n = 6), whereas the floor effect was 1.8% (n = 2). Additionally, the Ar-FJS showed correlation coefficients of 0.753 and 0.992 for the rWOMAC and SF-36, respectively.

CONCLUSION

The Ar-FJS-12 demonstrated excellent internal consistency, repeatability, construct validity, and content validity and can be recommended for patients in Arabic-speaking communities who have undergone knee arthroplasty.

Low Ceiling Effects of the Forgotten Joint Score Compared With Legacy Measures After Joint-Preserving Procedures: A Systematic Review

PURPOSE

To determine, in patients undergoing joint preservation procedures, whether the Forgotten Joint Score (FJS) compares favorably with legacy measures.

METHODS

Medical databases (including PubMed/MEDLINE and Embase databases) were queried for publications with the terms "Forgotten Joint Score" and "hip," "knee," "arthroscopy," or "ACL." Fourteen studies met the inclusion criteria. Methodologic quality was assessed through the Consensus-based Standards for the Selection of Health Measurement Instruments (COSMIN) checklist, and psychometric data were evaluated for ceiling or floor effects, convergent validity, internal consistency, reliability, responsiveness, measurement invariance, and measurement error by 2 fellowship-trained orthopaedic surgeons (B.D.K. and W.T.H.).

RESULTS

Data were collected from 14 studies using the FJS after joint-preserving procedures in 911 patients (959 joints). Four studies reported strong internal consistency with an average Cronbach α of 0.92. Two studies reported responsiveness with an effect size ranging from 0.6 to 1.16. One study reported reproducibility with an interclass correlation coefficient of 0.9 (95% confidence interval, 0.8-0.9). One study reported measurement error with an minimum detectable change (MDC)individual of 32% and MDCgroup of 4.5%. Studies reported moderate to very strong convergent validity across legacy measures for hip and knee preservation surgery. Ceiling effects were favorable compared with many legacy scores for hip and knee preservation. Three studies reported the minimal clinically important difference whereas 1 study reported the patient acceptable symptomatic state for the FJS.

CONCLUSIONS

The FJS is a methodologically sound outcome measure used to evaluate patient outcomes after hip and knee preservation surgery with overall low ceiling effects compared with legacy measures.

LEVEL OF EVIDENCE

Level IV, systematic review of Level III and IV studies.

Reliability and validity of the Forgotten Joint Score-12 for total ankle replacement and ankle arthrodesis

OBJECTIVES

This study evaluated the reliability and validity of the Forgotten Joint Score-12 (FJS-12)-a measure of patients' ability to forget their joints in daily life-in patients who underwent total ankle replacement (TAR) or ankle arthrodesis (AA).

METHODS

Patients who underwent TAR or AA were recruited from seven hospitals. The patients completed the Japanese version of FJS-12 twice, at an interval of two weeks, at a minimum of one year postoperatively. Additionally, they answered the Self-Administered Foot Evaluation Questionnaire and EuroQoL 5-Dimension 5-Level as comparators. The construct validity, internal consistency, test-retest reliability, measurement error, and floor and ceiling effects were evaluated.

RESULTS

A total of 115 patients (median age, 72 years), comprising 50 and 65 patients in the TAR and AA groups respectively, were evaluated. The mean FJS-12 scores were 65 and 58 for the TAR and AA groups, respectively, with no significant difference between groups (P = 0.20). Correlations between the FJS-12 and Self-Administered Foot Evaluation Questionnaire subscale scores were good to moderate. The correlation coefficient ranged from 0.39 to 0.71 and 0.55 to 0.79 in the TAR and AA groups, respectively. The correlation between the FJS-12 and EuroQoL 5-Dimension 5-Level scores was poor in both groups. The internal consistency was adequate, with Cronbach's α greater than 0.9 in both groups. The intraclass correlation coefficients of test-retest reliability was 0.77 and 0.98 in the TAR and AA groups, respectively. The 95% minimal detectable change values were 18.0 and 7.2 points in the TAR and AA groups, respectively. No floor or ceiling effect was observed in either group.

CONCLUSIONS

The Japanese version of FJS-12 is a valid and reliable questionnaire for measuring joint awareness in patients with TAR or AA. The FJS-12 can be a useful tool for the postoperative assessment of patients with end-stage ankle arthritis.

Robotic Arthroplasty Clinical and cost Effectiveness Randomised controlled trial (RACER-knee): a study protocol

INTRODUCTION

Robotic-assisted knee replacement systems have been introduced to healthcare services worldwide in an effort to improve clinical outcomes for people, although high-quality evidence that they are clinically, or cost-effective remains sparse. Robotic-arm systems may improve surgical accuracy and could contribute to reduced pain, improved function and lower overall cost of total knee replacement (TKR) surgery. However, TKR with conventional instruments may be just as effective and may be quicker and cheaper. There is a need for a robust evaluation of this technology, including cost-effectiveness analyses using both within-trial and modelling approaches. This trial will compare robotic-assisted against conventional TKR to provide high-quality evidence on whether robotic-assisted knee replacement is beneficial to patients and cost-effective for healthcare systems.

METHODS AND ANALYSIS

The Robotic Arthroplasty Clinical and cost Effectiveness Randomised controlled trial-Knee is a multicentre, participant-assessor blinded, randomised controlled trial to evaluate the clinical and cost-effectiveness of robotic-assisted TKR compared with TKR using conventional instruments. A total of 332 participants will be randomised (1:1) to provide 90% power for a 12-point difference in the primary outcome measure; the Forgotten Joint Score at 12 months postrandomisation. Allocation concealment will be achieved using computer-based randomisation performed on the day of surgery and methods for blinding will include sham incisions for marker clusters and blinded operation notes. The primary analysis will adhere to the intention-to-treat principle. Results will be reported in line with the Consolidated Standards of Reporting Trials statement. A parallel study will collect data on the learning effects associated with robotic-arm systems.

ETHICS AND DISSEMINATION

The trial has been approved by an ethics committee for patient participation (East Midlands-Nottingham 2 Research Ethics Committee, 29 July 2020. NRES number: 20/EM/0159). All results from the study will be disseminated using peer-reviewed publications, presentations at international conferences, lay summaries and social media as appropriate.

TRIAL REGISTRATION NUMBER

ISRCTN27624068.

Early muscle recovery following robotic-assisted unicompartmental knee arthroplasty

BACKGROUND

Robotic-assisted unicompartmental knee arthroplasty (UKA) improves implant accuracy, however whether this translates to patient function is less clear. Various outcomes have been reported but muscle recovery has not been previously investigated.

OBJECTIVE

To explore sequential change in lower limb muscle strength following robotic-assisted UKA with isokinetic dynamometry.

RESULTS

12 participants undergoing rUKA for medial compartment osteoarthritis were assessed pre-operatively, and at 6- and 12-weeks post-operatively. Maximal muscle strength changed over time in both quadriceps (p = 0.006) and hamstrings (p = 0.018) muscle groups. Quadriceps strength reduced from 88.52(39.86)Nm to 74.47(27.58)Nm by 6-weeks (p = 0.026), and then recovered to 90.41(38.76)Nm by 12-weeks (p = 0.018). Hamstring strength reduced from 62.45(23.18)Nm to 54.12(20.49)Nm by 6-weeks (p = 0.016), and then recovered to 55.07(17.99)Nm by 12-weeks (p = 0.028). By 12-weeks quadriceps strength was 70% and hamstrings 83% of the values achieved in the un-operated limb. Substantial improvement was seen in all other measures over time, with sequential positive change in Timed-up-and-go test (p = 0.015), 10 m walk test (p = 0.021), range of knee flexion (p = 0.016) and PROMs (p < 0.025).

A Modified Version of the Forgotten Joint Score-12 in Lower Limb Amputees: Validity and Reliability Study

Adaptation to prosthesis is important for occupation, quality of life, and participation in social life, so it needs to be evaluated. The aim of this study was to determine the validity and reliability of the Forgotten Joint Score-12 (FJS-12) in lower limb amputees. The FJS-12 was applied to 80 amputees. Criterion-referenced validity was assessed using the activity restriction subparameter of Trinity Amputation and Prosthesis Experience Scale (TAPES). The internal consistency of the FJS-12 was high (Cronbach's α = .943). A statistically significant very good negative correlation was determined between the FJS-12 and the activity restriction subparameter of TAPES (r = -.641; p < .001). The results of this study showed that FJS-12 is a valid and reliable measurement tool that can be used to assess the adaptation to prosthesis in amputees. Evaluation of prosthesis awareness in daily living activities of amputees is important in terms of establishing occupational therapy and rehabilitation programs.

Clinical outcome of Bioball universal adapter in revision hip arthroplasty

Background

Removal of a well-fixed uncemented femoral component in revision hip arthroplasty is challenging. A modular head-neck adapter provides an option to optimise the femoral offset and anteversion, avoiding the need for femoral stem revision.

Aim

To present the clinical results following revision arthroplasty with the Bioball head-neck adapter in the elderly American Society of Anaesthesiologists (ASA) Grade II, III & IV patients.

Materials and methods

A retrospective review of our database was performed, and all patients classed as ASA grades II, III, & IV treated with the Bioball Universal Adapter (BUA) for 10 years were included. The indication for revision, stem retention, type of adapter, and head size were identified. Patients were contacted by a research nurse to assess the Forgotten Joint Score (FJS), the Oxford Hip Score (OHS), and any symptoms of instability at a minimum of one year post revision surgery.

Results

Our study included 47 patients. 5 (10.6%) were ASA II, 19 (40.4%) were ASA III and 23 (49%) were ASA IV. The mean age was 74 years. The mean follow up was 52 months ± 28.4 SD. The median FJS was 86 ± 11.6 SD. The median OHS was 43 ± 6.2 SD. One patient (2.1%) developed recurrent dislocation following lumbar spinal fusion. None of the other patients experienced instability. The survival rate for the adapter was 98%.

Conclusion

The BUA gives good clinical outcomes with very low post revision instability. It is a valuable option for the elderly because it avoids the morbidity and risks associated with the removal of a well-fixed femoral stem.

Level of Evidence

Level IV.

A comparison of clinical thresholds for revision following total and unicompartmental knee arthroplasty

Unicompartmental knee arthroplasty (UKA) has higher revision rates than total knee arthroplasty (TKA). As revision of UKA may be less technically demanding than revision TKA, UKA patients with poor functional outcomes may be more likely to be offered revision than TKA patients with similar outcomes. The aim of this study was to compare clinical thresholds for revisions between TKA and UKA using revision incidence and patient-reported outcomes, in a large, matched cohort at early, mid-, and late-term follow-up. Analyses were performed on propensity score-matched patient cohorts of TKAs and UKAs (2:1) registered in the New Zealand Joint Registry between 1 January 1999 and 31 December 2019 with an Oxford Knee Score (OKS) response at six months (n, TKA: 16,774; UKA: 8,387), five years (TKA: 6,718; UKA: 3,359), or ten years (TKA: 3,486; UKA: 1,743). Associations between OKS and revision within two years following the score were examined. Thresholds were compared using receiver operating characteristic analysis. Reasons for aseptic revision were compared using cumulative incidence with competing risk. Fewer TKA patients with 'poor' outcomes (≤ 25) subsequently underwent revision compared with UKA at six months (5.1% vs 19.6%; p < 0.001), five years (4.3% vs 12.5%; p < 0.001), and ten years (6.4% vs 15.0%; p = 0.024). Compared with TKA, the relative risk for UKA was 2.5-times higher for 'unknown' reasons, bearing dislocations, and disease progression. Compared with TKA, more UKA patients with poor outcomes underwent revision from early to long-term follow-up, and were more likely to undergo revision for 'unknown' reasons, which suggest a lower clinical threshold for UKA. For UKA, revision risk was higher for bearing dislocations and disease progression. There is supporting evidence that the higher revision UKA rates are associated with lower clinical thresholds for revision and additional modes of failure.

Total Hip Replacement: Psychometric Validation of the Italian Version of Forgotten Joint Score (FJS-12)

BACKGROUND

One million Total Hip Replacements (THA) are thought to be performed annually. To measure prosthesis awareness throughout daily activities, the FJS-12 patient-reported outcome scale was developed. This article's goal is to undertake a psychometric validation of the Italian FJS-12 among a sample of related THA patients.

METHODS

Between January and July 2019, data from 44 patients were retrieved. The participants were required to complete the Italian version of FJS-12 and of the WOMAC at preoperative follow-up, after two weeks, 1, 3, and 6 months postoperatively.

RESULTS

The Pearson correlation coefficient between the FJS-12 and WOMAC was 0.287 (p = 0.002) at preoperative follow-up, r = 0.702 (p < 0.001) at 1 month, r = 0.516 (p < 0.001) at 3 months and r = 0.585 (p < 0.001) at 6 months. The ceiling effect surpassed the acceptable range (15%) for FJS-12 in 1 month (25.5%) and WOMAC in 6 months follow-up (27.3%).

CONCLUSIONS

The psychometric validation of the Italian version of this score for THA was executed with acceptable results. FJS-12 and WOMAC reported no ceiling and floor effects. Therefore, to distinguish between patients who had good or exceptional results following UKA, the FJS-12 could be a reliable score. Under the first four months, FJS-12 had a smaller ceiling effect than WOMAC. It is recommended to use this score in clinical research concerning the outcomes of THA.

Patella resurfacing is not associated with a difference in the Oxford knee score after total knee arthroplasty but stair descent is enhanced

BACKGROUND

The primary aim was to assess the Oxford knee scores (OKS) on patients who underwent a total knee arthroplasty (TKA) with patellar resurfacing compared to those who did not. Secondary aims were to identify: (1) factors associated with resurfacing, (2) the effect of resurfacing on specific components of the OKS related to patellofemoral function, (3) the influence on patient satisfaction, and (4) whether a subgroup of patients had an improved outcome when resurfacing was undertaken.

METHODS

A retrospective cohort study was undertaken using outcome data from the arthroplasty database held at the study centre. Patient demographics and OKS were collected preoperatively and at 1 and 2 years postoperatively. Patient satisfaction was assessed at 1 and 2 years postoperatively.

RESULTS

Three thousand one hundred and twenty-two patients met the inclusion criteria of which 46.5% (n = 1453) underwent resurfacing. There were no differences in the OKS change at 1 or 2 years between those undergoing and not undergoing resurfacing (difference 0.2, p ≥ 0.469). Patients undergoing resurfacing were more likely to be female (odds ratio (OR) 1.53, 95% CI 1.30-1.79, p < 0.001), undergo a posterior stabilised knee (OR 6.87, 95% CI 5.71-8.27, p < 0.001) or had a worse response to question 5-standing from a chair, (p = 0.011) or 12-stair descent, (p = 0.017) of the OKS preoperatively. There was no difference in postoperative patient satisfaction (p ≥ 0.180). There was a significantly greater improvement in question 12 of the OKS at 1 year (p = 0.019) in the resurfaced group. There were no patient-related factors or symptoms that were associated with a clinically significant (≥ 5 points) greater postoperative OKS.

CONCLUSION

Patella resurfacing was not associated with a clinically important improvement in OKS. No specific indications for patella resurfacing were identified that offered an improved outcome, but when it was undertaken there was a greater improvement in the ability to descend stairs. Level of evidence Retrospective diagnostic study, Level III.

Psychometric properties of the Italian version of the Forgotten Joint Score in patients with total hip arthroplasty

Total hip arthroplasty (THA) surgeries are increasing; to assess quality of life after THA, an instrument that considers patient's perspective on surgical outcomes is necessary. The objective of this study is to assess the psychometric properties of the Italian version of the Forgotten Joint Score (FJS-I) in patients with THA. The FJS-I was administered to 111 patients with THA, as well as the Western Ontario and McMaster Universities (WOMAC), Numerical Pain Rating Scale (NPRS), and the EuroQol 5D-5L (EQ-5D-5L). Structural validity [confirmatory factor analysis (CFA)], internal consistency (Cronbach's alpha), test-retest reliability [intraclass correlation coefficient (ICC 2,1 )], measurement error [standard error of the measurement (SEM)], and construct validity (hypothesis testing with correlation of the WOMAC, NPRS, and EQ-5D-5L) were assessed. In addition, the minimal detectable change (MDC) was computed. The result of CFA confirmed the one-factor structure. Internal consistency was supported (α = 0.944). A high test-retest reliability (ICC = 0.958; 95% confidence interval, 0.914-0.980) was found with an SEM and an MDC of 5.3 and 16.6 points, respectively. The a-priori hypotheses were fully met, determining the construct validity to be satisfactory. Psychometric properties of the FJS-I were confirmed, and it can be used for single-person assessment. Further research is suggested to refine its structural validity.

Multiple Imputation to Salvage Partial Respondents: Analysis of the Forgotten Joint Score-12 After Total Hip Arthroplasty

BACKGROUND

Missing responses are common when Asian patients complete the Forgotten Joint Score-12 (FJS-12), which is widely used to evaluate total hip arthroplasty (THA). We aimed to provide orthopaedic researchers with a solution for handling missing values in such patient-reported outcome measures (PROMs).

METHODS

Patients who had undergone primary THA between 1998 and 2016 (n = 1,021) were investigated in 2020. The FJS-12 and 9 other PROMs, including questions related to Asian lifestyle activities, were administered. Risk factors for missing FJS-12 items were investigated. Partial respondents were matched with complete respondents; then, in each pair, the items not completed by the partial respondent were deleted from the responses of the complete respondent. Predictive mean matching (PMM) was performed in an attempt to recover the deleted items, using 65 sets of imputation models. After the missing values had been imputed, we explored patient characteristics that affected the FJS-12, using data from all complete and partial respondents.

RESULTS

A total of 652 patients responded to the survey (393 complete and 193 partial respondents). Partial respondents were older, more often female, and less active. Older respondents were more likely to skip items involving the bed, while those who reported a better ability to sit in the seiza style (traditional Japanese floor sitting) were more likely to skip items about chair sitting. The imputed FJS-12 value exhibited excellent reliability (intraclass correlation coefficient for agreement with the true scores, 0.985). FJS-12 values of complete respondents were significantly higher than those of respondents with 4 to 11 missing items (51.6 versus 32.8, p < 0.001). Older age was associated with higher FJS-12 values, which was revealed only via analysis of the multiply imputed data sets (p < 0.001).

CONCLUSIONS

Analysis of only complete FJS-12 responses after THA resulted in a nonresponse bias, preferentially excluding older, female, and less active individuals and those with a traditional floor living style. Multiple imputation could provide a solution to scoring and analyzing PROMs with missing responses by permitting the inclusion of partial respondents.

LEVEL OF EVIDENCE

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

Validation of Single-Outcome Questionnaire in Primary TKA and THA

BACKGROUND

Patient-reported outcome measures can be used to evaluate post-operative health care quality and patient satisfaction. The Patient's Joint Perception (PJP) question gathers a single patient-reported outcome to measure how patients appraise their joint. This study compares PJP to the Forgotten Joint Score (FJS) at 21 months post-operation to assess its value.

METHODS

A retrospective review was performed at an orthopedic specialty hospital for patients who completed both PJP and FJS questionnaires in 2020-2021 and underwent either a unilateral elective primary Total Knee Arthroplasty (TKA) or Total Hip Arthroplasty (THA). Spearman's correlation coefficients and P-values were calculated to determine external validity of PJP. Floor and ceiling effects were analyzed and considered present if ≥ 15% of patients achieved the worst or best score (0-4 for PJP and 0-100 for FJS).

RESULTS

In total, 534 patients (327 THA and 207 TKA) were surveyed at 21 months post-operation. External validity against FJS was assessed for both TKA (r = 0.66, P < .01) and THA (r = 0.69, P < .01). For TKA, the floor and ceiling effects were 0.97% and 25.12% for PJP and 3.86% and 4.83% for FJS, respectively. For THA, the floor and ceiling effects were 0.92% and 50.46% for PJP and 2.47% and 20.50% for FJS, respectively.

CONCLUSION

The PJP was correlated with FJS moderately for both TKA and THA and can be collected with lesser burden. However, ceiling effects were higher in both TKA and THA for PJP compared to FJS. Further studies are needed to investigate the questionnaires at additional time points and to evaluate the implications of high ceiling effects.

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.

Early Results of a Randomized Controlled Trial of Partial Versus Total Knee Arthroplasty

BACKGROUND

Debate still exists regarding the benefits of unicompartmental (UKA) versus total knee arthroplasty (TKA) for the treatment of medial compartment osteoarthritis. The purpose of this randomized trial is to compare the early outcomes of UKA versus TKA.

METHODS

One-hundred and seven candidates for UKA were randomized at two centers; 57 candidates received UKA and 50 received TKA. Six-week and 6-month outcome measures including Knee Injury and Osteoarthritis Outcome Score, Joint Replacement (KOOS, JR), Knee Society Score (KSS), Forgotten Joint Score (FJS), and VR-12 global health scores were obtained. No demographic or baseline patient reported outcome (PRO) differences were present suggesting successful randomization (P > .05).

RESULTS

UKA demonstrated shorter operative times (UKA = 65 minutes, TKA = 74 minutes; P < .001) and length of stay (UKA = 0.7 nights, TKA = 1.2 nights; P < .01). At 6 weeks, there were no differences in KOOS, JR (P = .755), KSS (P = .754), FJS (P = .664), or PRO change from preoperative scores (P = .468). There were three surgical complications within 90 days in each group. The duration of opioid consumption (UKA = 33.8 days, TKA = 28.5 days; P = .290) and return to work (UKA = 57.1 days, TKA = 47.3 days; P = .346) did not differ between groups.

CONCLUSION

Data suggest no clinically significant differences between UKA and TKA in the early postoperative period in regards to patient-reported outcome measures, duration of opioid use, or return to work. Patients undergoing UKA can anticipate a shorter length of stay and greater early range of motion. All-cause short-term complications may be more prevalent with TKA.

Investigating and defining outcomes of suprapatellar versus infrapatellar intramedullary nailing of tibial shaft fractures: a protocol for a pilot randomised controlled trial

Background

Anterior knee pain is often reported following intramedullary nailing of tibial shaft fractures. The aetiology remains unclear, but the surgical approach may play an important role. To date, no biomechanically validated method exists to assess patient outcomes specific to anterior knee pain in this cohort. The central aims of this study are to (1) evaluate the feasibility of a full-scale randomised controlled trial (RCT) investigating the influence of surgical approach on intramedullary nailing of tibial shaft fractures (suprapatellar versus infrapatellar nailing), (2) explore differences in clinical outcomes between the approaches, and (3) explore the development of a biomechanically validated methodology for assessing post-operative anterior knee pain and knee function specific to intramedullary nailing of tibial shaft fractures.

Methods

This pilot study will follow a prospective randomised controlled design at the Royal Adelaide Hospital and The Queen Elizabeth Hospital (South Australia). This study aims to recruit 60 patients between 18 and 60 years old who will be randomly assigned to either the suprapatellar or infrapatellar approach following a decision for intramedullary surgical fixation by the treating surgeon. All nails in this study will be Stryker T2 Alpha nails. Patients will undergo standard radiograph, magnetic resonance imaging, and clinical assessments in-line with their standard operative care, and complete a number of patient-reported and performance-based outcome measures. Performance-based outcome measures will be assessed utilising three-dimensional motion capture techniques. Follow-up time points are 3, 6, 12, and 18 months. Feasibility outcomes include ability to meet enrolment and retention metrics, compliance with all questionnaires and assessment procedures, and the occurrence of any adverse events. The primary clinical outcome is the incidence of anterior knee pain at 12 months after surgery.

Discussion

This study will establish the feasibility and inform the design of a large-scale RCT. Evaluation of all clinical data and patient outcomes will lead to the development of a new tool for assessing patient outcomes in this cohort. Limitations of the study include an unpredictable enrolment rate and loss to follow-up, small sample size, and the unknown ability of three-dimensional motion analysis to pick up the effects of anterior knee pain after tibial nailing.

Trial registration

This trial was prospectively registered on the 7 February 2020 on ANZCTR, ACTRN12620000109909.

Midterm Survivorship of Robotic-Assisted Lateral Unicompartmental Knee Arthroplasty

BACKGROUND

Lateral unicompartmental knee arthroplasty (UKA) is a popular alternative to total knee arthroplasty (TKA) for patients with isolated lateral compartment osteoarthritis. Few studies have investigated outcomes following robotic-assisted lateral UKA. The purpose of this study is to evaluate mid-term survivorship and patient-reported outcomes of robotic-assisted lateral UKA.

METHODS

A retrospective case series was conducted on all robotic-assisted lateral UKAs performed by a single surgeon between 2013 and 2019. Patient demographics, surgical variables, and Kozinn and Scott criteria were collected. Implant survivorship was estimated using the Kaplan-Meier method with all-cause reoperation and conversion to TKA as endpoints. Participating patients were assessed for patient satisfaction and the Forgotten Joint Score-12. Correlations between patient demographics and patient outcome scores were investigated.

RESULTS

In total, 120 lateral UKAs were identified, 84 of which met inclusion criteria, with a mean follow-up of 4.0 years (range 2.0-7.0). Five-year survivorship was 92.9% (95% confidence interval [CI] 84.5-96.7) with all-cause reoperation as the endpoint, and 100% (95% CI 95.0-100) with conversion to TKA as the endpoint. One patient was converted to TKA after the 5-year mark, resulting in a 6-year survival for conversion to TKA of 88.9% (95% CI 44.9-98.5). Average Forgotten Joint Score-12 score was 82.7/100, and patient satisfaction 4.7/5. Mean coronal plane correction was 2.5° ± 1.9° toward the mechanical axis. Neither final postoperative alignment nor failure to meet classic Kozinn and Scott criteria for UKA resulted in differences in patient-reported outcomes.

CONCLUSION

The current study demonstrates high mid-term survivorship and excellent patient-reported outcomes with robotic-assisted lateral UKA. Robotic-assisted lateral UKA is a viable treatment option for isolated lateral compartment arthritis even in patients who do not meet classic indications.

The metabolic equivalent of task score : a useful metric for comparing high-functioning hip arthroplasty patients

AIMS

This study investigates the use of the metabolic equivalent of task (MET) score in a young hip arthroplasty population, and its ability to capture additional benefit beyond the ceiling effect of conventional patient-reported outcome measures.

METHODS

From our electronic database of 751 hip arthroplasty procedures, 221 patients were included. Patients were excluded if they had revision surgery, an alternative hip procedure, or incomplete data either preoperatively or at one-year follow-up. Included patients had a mean age of 59.4 years (SD 11.3) and 54.3% were male, incorporating 117 primary total hip and 104 hip resurfacing arthroplasty operations. Oxford Hip Score (OHS), EuroQol five-dimension questionnaire (EQ-5D), and the MET were recorded preoperatively and at one-year follow-up. The distribution was examined reporting the presence of ceiling and floor effects. Validity was assessed correlating the MET with the other scores using Spearman's rank correlation coefficient and determining responsiveness. A subgroup of 93 patients scoring 48/48 on the OHS were analyzed by age, sex, BMI, and preoperative MET using the other metrics to determine if differences could be established despite scoring identically on the OHS.

RESULTS

Postoperatively the OHS and EQ-5D demonstrate considerable negatively skewed distributions with ceiling effects of 41.6% and 53.8%, respectively. The MET was normally distributed postoperatively with no relevant ceiling effect. Weak-to-moderate significant correlations were found between the MET and the other two metrics. In the 48/48 subgroup, no differences were found comparing groups with the EQ-5D, however significantly higher mean MET scores were demonstrated for patients aged < 60 years (12.7 (SD 4.7) vs 10.6 (SD 2.4), p = 0.008), male patients (12.5 (SD 4.5) vs 10.8 (SD 2.8), p = 0.024), and those with preoperative MET scores > 6 (12.6 (SD 4.2) vs 11.0 (SD 3.3), p = 0.040).

CONCLUSION

The MET is normally distributed in patients following hip arthroplasty, recording levels of activity which are undetectable using the OHS. Cite this article: Bone Joint Res 2022;11(5):317-326.

Intraoperative pressure sensors improve soft-tissue balance but not clinical outcomes in total knee arthroplasty: a multicentre randomized controlled trial

AIMS

Intraoperative pressure sensors allow surgeons to quantify soft-tissue balance during total knee arthroplasty (TKA). The aim of this study was to determine whether using sensors to achieve soft-tissue balance was more effective than manual balancing in improving outcomes in TKA.

METHODS

A multicentre randomized trial compared the outcomes of sensor balancing (SB) with manual balancing (MB) in 250 patients (285 TKAs). The primary outcome measure was the mean difference in the four Knee injury and Osteoarthritis Outcome Score subscales (ΔKOOS₄) in the two groups, comparing the preoperative and two-year scores. Secondary outcomes included intraoperative balance data, additional patient-reported outcome measures (PROMs), and functional measures.

RESULTS

There was no significant difference in ΔKOOS₄ between the two groups at two years (mean difference 0.4 points (95% confidence interval (CI) -4.6 to 5.4); p = 0.869), and multiple regression found that SB was not associated with a significant ΔKOOS₄ (0.2-point increase (95% CI -5.1 to 4.6); p = 0.924). There were no significant differences between groups in other PROMs. Six-minute walking distance was significantly increased in the SB group (mean difference 29 metres; p = 0.015). Four-times as many TKAs were unbalanced in the MB group (36.8% MB vs 9.4% SB; p < 0.001). Irrespective of group assignment, no differences were found in any PROM when increasing ICPD thresholds defined balance.

CONCLUSION

Despite improved quantitative soft-tissue balance, the use of sensors intraoperatively did not differentially improve the clinical or functional outcomes two years after TKA. These results question whether a more precisely balanced TKA that is guided by sensor data, and often achieved by more balancing interventions, will ultimately have a significant effect on clinical outcomes. Cite this article: Bone Joint J 2022;104-B(5):604-612.

Evaluation of consistency of patient-satisfaction score in the 2011 Knee Society Score to other patient-reported outcome measures

BACKGROUND

Patient-reported outcome measures (PROMs) are important aspects of evaluating clinical outcomes after total knee arthroplasty (TKA). The patient-satisfaction score in the 2011 Knee Society Score (KSS) is one of the most frequently used questionnaires; however, patient satisfaction is a subjective assessment and is affected by multiple factors. Therefore, we evaluated correlations between the patient-satisfaction score in the 2011 KSS and that of other categories of the 2011 KSS as well as other PROMs. Furthermore, the ceiling effects of each PROMS were also investigated.

METHODS

We enrolled 85 patients aged ≥65 years who underwent cruciate retaining TKA. Patients completed various questionnaires, including the 2011 KSS, Forgotten Joint Score-12 (FJS-12), EuroQol 5 Dimension (EQ-5D), and Geriatric Locomotive Function Scale (GLFS-25), one year after TKA. Simple linear regression analysis was used to evaluate correlations between each PROM and the patient-satisfaction score in the 2011 KSS. Ceiling effects of the patient-satisfaction score in the 2011 KSS, FJS-12, EQ-5D and GLFS-25 were evaluated by comparing the number of patients categorized into the top 10% with each PROM.

RESULTS

All scores were significantly correlated (p < 0.001) with the patient-satisfaction score in the 2011 KSS (symptoms: r = 0.69, functional activities: r = 0.69, patient expectations: r = 0.73, FJS-12: r = 0.72, EQ-5D: r = 0.67, GLFS-25: r = -0.74). The patient-satisfaction score in the 2011 KSS and GLFS-25 showed a ceiling effect. On the other hand, this effect was not observed in the results of the FJS-12 and EQ-5D.

CONCLUSIONS

The patient-satisfaction score in the 2011 KSS correlated with other PROMs, and the indicated level of satisfaction was consistent. The results of the FJS-12 and EQ-5D had good positive correlation to patient satisfaction without ceiling effect.

The Forgotten Joint Score patient-acceptable symptom state following primary total hip arthroplasty

AIMS

The Forgotten Joint Score-12 (FJS-12) is a validated patient-reported outcome measure (PROM) tool designed to assess artificial prosthesis awareness during daily activities following total hip arthroplasty (THA). The patient-acceptable symptom state (PASS) is the minimum cut-off value that corresponds to a patient's satisfactory state-of-health. Despite the validity and reliability of the FJS-12 having been previously demonstrated, the PASS has yet to be clearly defined. This study aims to define the PASS of the FJS-12 following primary THA.

METHODS

We retrospectively reviewed all patients who underwent primary elective THA from 2019 to 2020, and answered both the FJS-12 and the Hip Disability and Osteoarthritis Outcome Score, Joint Replacement (HOOS, JR) questionnaires one-year postoperatively. HOOS, JR score was used as the anchor to estimate the PASS of FJS-12. Two statistical methods were employed: the receiver operating characteristic (ROC) curve point, which maximized the Youden index; and 75th percentile of the cumulative percentage curve of patients who had the HOOS, JR score difference larger than the cut-off value.

RESULTS

This study included 780 patients. The mean one-year FJS-12 score was 65.42 (SD 28.59). The mean one-year HOOS, JR score was 82.70 (SD 16.57). A high positive correlation between FJS-12 and HOOS, JR was found (r = 0.74; p<0.001), making the HOOS, JR a valid external anchor. The threshold score of the FJS-12 that maximized the sensitivity and specificity for detecting a PASS was 66.68 (area under the curve = 0.8). The cut-off score value computed with the 75th percentile approach was 92.20.

CONCLUSION

The PASS threshold for the FJS-12 at one year following primary THA was 66.68 and 92.20 using the ROC curve and 75th percentile approaches, respectively. These values can be used to achieve consensus about meaningful postoperative improvement to maximize the utility of the FJS-12 to evaluate and counsel patients undergoing THA. Cite this article: Bone Jt Open 2022;3(4):307-313.

Unicompartmental knee arthroplasty: the Italian version of the Forgotten Joint Score-12 is valid and reliable to assess prosthesis awareness

PURPOSE

Unicompartmental Knee Arthroplasty (UKA) recorded an increased incidence of around 30% per year in the United States. Patient's experience and satisfaction after surgery were traditionally assessed by pre, and post-surgical scores and Patient-Reported Outcome Measures (PROMs) scales. Traditional scales as Western Ontario and McMaster University Osteoarthritis Index (WOMAC) and Oxford Knee Score (OKS) reported high ceiling effect. Patients treated by UKA usually perform well; therefore, it is necessary to have a PROMs' scale with a low ceiling effect as the Forgotten Joint Score-12 (FJS-12). PROMs have to be validated in the local language to be used. This study aims to perform a psychometric validation of the Italian version of FJS-12 for UKA for the first time.

METHODS

Between January 2019 and October 2019, 44 patients were included. Each patient completed both the FJS-12 Italian version and the WOMAC Italian version in preoperative follow-up, after 2-week and 1-month, 3-month, and 6-month postoperative follow-up. Cronbach's α, intraclass correlation coefficient (ICC), standard error of measurement (SEM), and minimal detectable change (MDC) were calculated to evaluate the reliability. The Pearson coefficient was used to assess validity. The Effect Size (ES) was used to test the responsiveness.

RESULTS

A range of Cronbach's α between 0.90 and 0.95 indicated good internal consistency for the FJS-12. The test-retest reliability was acceptable (i.e., the ICC was higher than 0.7) at each follow-up. The Pearson correlation coefficient between the FJS-12 and WOMAC was - 0.11 (n.s.) at preoperative follow-up, r = 0.47 (P = 0.001) at 1 month, r = 0.57 (P < 0.001) at 3 months, and r = 0.57 (P < 0.001) at 6 months. Therefore, except for the preoperative period, the validity of the FJS-12 score was assessed.

CONCLUSION

The FJS-12 represents a valid and reliable tool with a low ceiling effect to assess the outcomes improvement in UKA patients. Therefore, validating and translating this score in different languages could help perform more accurate studies on outcomes after UKA.

LEVEL OF EVIDENCE

Level III, diagnostic study.

Personalized Hip Joint Replacement with Large Diameter Head: Current Concepts

Hip arthroplasty is a common procedure in elective orthopaedic surgery that has excellent outcomes. Hip replacement surgery aims to create a “forgotten” joint, i.e., a pain-free joint akin to a native articulation. To achieve such goals, hip arthroplasty must be personalised. This is achieved by restoring: the centre of rotation of the native hip; leg length equality; femoral offset; femoral orientation; soft tissue tension; joint stability with an unrestricted hip range of motion; and having appropriate stress transfer to the bone. In addition, the whole pathway should provide an uneventful and swift postoperative recovery and lifetime implant survivorship with unrestricted activities. At our institution, the preferred option is a personalized total hip arthroplasty (THA) with a large diameter head (LDH) using either monobloc or dual-mobility configuration for the acetabular component. LDH THA offers an impingement-free range of motion and a reduced risk of dislocation. The larger head-neck offset allows for a supraphysiologic range of motion (ROM). This can compensate for a patient’s abnormal spinopelvic mobility and surgical imprecision. Additionally, LDH bearing with a small clearance exerts a high suction force, which provides greater hip micro-stability. With appropriate biomechanical reconstruction, LDH THA can restore normal gait parameters. This results in unrestricted activities and higher patient satisfaction scores. We use LDH ceramic on ceramic for our patients with a life expectancy of more than 20 years and use LDH dual mobility bearings for all others.

Traditional Chinese-Hong Kong version of Forgotten Joint Score-12 (FJS-12) for patients with osteoarthritis of the knee underwent joint replacement surgery: cross-cultural and sub-cultural adaptation, and validation

Background

A patient-reported outcome (PRO) tool which reflects the outcomes of patients underwent total knee arthroplasty (TKA) are important to be “ceiling effect free” which commonly used PRO tools face. Forgotten joint score-12 (FJS-12) has been proved to reduce or even free from ceiling effect. FJS-12 has been translated to different languages. The objectives of this study are to validate FJS-12 in Traditional Chinese-Hong Kong language and look for the goodness of FJS-12 still exist in this language adapted FJS-12 version.

Methods

FJS-12 was administered to 75 patients whose majority was obese underwent TKA between September 2019 and March 2020. Patients completed 3 sets of questionnaires (FJS-12, Oxford Knee Score (OKS), and Numeric Rating Scale (NRS)) twice, 2 weeks apart. Reliability, internal consistency, responsiveness, test–retest agreement and discriminant validity were evaluated.

Results

Reliability of FJS-12 showed moderate to excellent internal consistency (Cronbach’s α = 0.870). Test–retest reliability of FJS-12 was good (ICC = 0.769). Bland–Altman plot showed good test–retest agreement. Construct validity in terms of correlations between FJS-12 and OKS, and FJS-12 and NRS were moderate at baseline (Pearson’s coefficient r = 0.598) and good at follow-up (r = 0.879). Smallest detectable change (Responsiveness) was higher than MIC. Floor effect was none observed, and ceiling effect was low. Discriminant validity was found to have no significance. BMI (obesity) did not affect FJS-12 outcomes.

Conclusions

The Traditional Chinese-Hong Kong version of FJS-12 showed good test–retest reliability, validity, responsiveness, BMI non-specific, with no floor and low ceiling effects for patients who underwent TKA. Sub-culture differences in individual PRO tools should be considered in certain ethnicities and languages.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12891-022-05156-5.

A Patient and Public Involvement Study to Explore the Need for Further Research into the Experience of Younger Patients Undergoing Total Hip Arthroplasty

Background: Total Hip Arthroplasty (THA) is one of the most commonly performed operations in orthopaedics. It is an operation usually performed in older patients, however the need for THA in younger patients is increasing. There is a lack of literature examining whether current recovery pathways address the specific needs of younger patients. Public and Patient Involvement (PPI) is a core aspect of good research practice and is recommended throughout the research process, including the formulation and refinement of pertinent research questions. Therefore, the explicit aim of this PPI study was to collect qualitative data from patients on the feasibility and requirement for further research into the experience of younger hip arthroplasty patients. Methods: Qualitative data was collected via an online questionnaire that was advertised on social media, requesting the input of anybody who had experienced a lower limb musculoskeletal injury or condition before the age of 50. The survey asked the respondents to describe their experiences and reflect on their priorities and goals throughout their recovery. Results: There were 71 respondents, of which 90% were female, with an average age of 43. Qualitative responses identified many concerns that were issues that could be translated across all patient ages. However, other priorities were raised that are not always recognised as important when measuring successful outcomes after a THA. Furthermore, many respondents described not feeling listened to by clinicians or treatment options not being sufficiently addressed and explored. Multiple respondents reported being told they were too young to have anything serious or that nothing could be done until they were older. Conclusions: The responses to the survey indicate that current care pathways are not fulfilling the needs and priorities in younger patients. Further research is required to explore these priorities and goals in more depth in order to understand how healthcare professionals can address them.

The influence of obesity on achievement of a 'forgotten joint' following total knee arthroplasty

INTRODUCTION

Obesity has been associated with poorer outcomes following total knee arthroplasty (TKA); however, data remain sparse on its impact on patients' joint awareness following surgery. This study aims to investigate the impact of body mass index (BMI) on improvement in outcomes following TKA as assessed by the Forgotten Joint Score-12 (FJS-12).

MATERIALS AND METHODS

We retrospectively reviewed 1075 patients who underwent primary TKA from 2017 to 2020 with available postoperative FJS-12 scores. Patients were stratified based on their BMI (kg/m²): < 30, 30.0-34.9 (obese class I), 35.0-39.9 (obese class II), and ≥ 40 (obese class III). FJS-12 and KOOS, JR scores were collected at various time points. Demographic differences were assessed with Chi-square and ANOVA tests. Mean scores between BMI groups were compared using univariate ANCOVA, controlling for observed demographic differences.

RESULTS

Of the 1075 patients included, there were 457 with a BMI < 30, 331 who were obese class I, 162 obese class II, and 125 obese class III. There were no statistical differences in FJS-12 scores between the BMI groups at 3 months (27.24 vs. 25.33 vs. 23.57 vs. 22.48; p = 0.99), 1 year (45.07 vs. 41.86 vs. 40.51 vs. 36.22; p = 0.92) and 2 years (51.31 vs. 52.86 vs. 46.17 vs. 44.97; p = 0.94). Preoperative KOOS, JR scores significantly differed between the various BMI categories (49.33 vs. 46.63 vs. 44.24 vs. 39.33; p < 0.01); however, 3-month (p = 0.20) and 1-year (p = 0.13) scores were not statistically significant. Mean improvement in FJS-12 scores from 3 months to 2 years was statistically greatest for obese class I patients and lowest for obese class III patients (24.07 vs. 27.53 vs. 22.60 vs. 22.49; p = 0.01). KOOS, JR score improvement from baseline to 1 year was statistically greatest for obese class III patients and lowest for non-obese patients (22.34 vs. 25.49 vs. 23.77 vs. 27.58; p < 0.01).

CONCLUSION

While all groups demonstrated postoperative improvement, those with higher BMI reported lower mean FJS-12 scores but these differences were not found to be significant. Our study showed no significant impact of BMI on postoperative joint awareness, which implies that obese patients, in all obesity classes, experience similar functional improvement following TKA.

LEVEL III EVIDENCE

Retrospective Cohort Study.

Robotic-arm assisted total knee arthroplasty is associated with improved accuracy and patient reported outcomes: a systematic review and meta-analysis

This systematic review and meta-analysis were conducted to compare the accuracy of component positioning, alignment and balancing techniques employed, patient-reported outcomes, and complications of robotic-arm assisted total knee arthroplasty (RATKA) with manual TKA (mTKA) and the associated learning curve. Searches of PubMed, Medline and Google Scholar were performed in October 2020 using PRISMA guidelines. Search terms included "robotic", "knee" and "arthroplasty". The criteria for inclusion were published clinical research articles reporting the learning curve for RATKA and those comparing the component position accuracy, alignment and balancing techniques, functional outcomes, or complications with mTKA. There were 198 articles identified, following full text screening, 16 studies satisfied the inclusion criteria and reported the learning curve of rTKA (n=5), component positioning accuracy (n=6), alignment and balancing techniques (n=7), functional outcomes (n=7), or complications (n=5). Two studies reported the learning curve using CUSUM analysis to establish an inflexion point for proficiency which ranged from 7 to 11 cases and there was no learning curve for component positioning accuracy. The meta-analysis showed a significantly lower difference between planned component position and implanted component position, and the spread was narrower for RATKA compared with the mTKA group (Femur coronal: mean 1.31, 95% confidence interval (CI) 1.08-1.55, p<0.00001; Tibia coronal: mean 1.56, 95% CI 1.32-1.81, p<0.00001). Three studies reported using different alignment and balancing techniques between mTKA and RATKA, two studies used the same for both group and two studies did not state the methods used in their RATKA groups. RATKA resulted in better Knee Society Score compared to mTKA in the short-to-mid-term follow up (95%CI [- 1.23,  - 0.51], p=0.004). There was no difference in arthrofibrosis, superficial and deep infection, wound dehiscence, or overall complication rates. RATKA demonstrated improved accuracy of component positioning and patient-reported outcomes. The learning curve of RATKA for operating time was between 7 and 11 cases. Future well-powered studies on RATKAs should report on the knee alignment and balancing techniques utilised to enable better comparisons on which techniques maximise patient outcomes.Level of evidence III.

Translation and Validation of the Korean Version of the Forgotten Joint Score

Backgroud

The Forgotten Joint Score (FJS) is a newly developed patient-reported outcome measure designed to evaluate clinical outcome after total knee arthroplasty (TKA). The FJS is known as a sensitive test with a low ceiling effect. It has been recently translated into many languages. However, no study has reported the validity or reliability of a Korean version of the FJS (K-FJS). Thus, the purpose of this study was to address this issue.

Methods

According to guidelines for cross-cultural adaptation, translation of the English version of the FJS was performed. After obtaining a license from the original developer, 150 patients who had undergone TKA at more than 1 year to less than 5 years ago completed the K-FJS, visual analog scale, Western Ontario and McMaster Universities Osteoarthritis index (WOMAC), and the 36-Item Short Form (SF-36) health survey. To measure test-retest reliability, the K-FJS was completed twice by telephone survey for 100 patients. Responsiveness was retrospectively calculated based on a survey of 50 patients at 3 months and 1 year after surgery.

Results

The K-FJS exhibited an excellent reliability (Cronbach's α, 0.967; intraclass correlation coefficient, 0.958; 95% confidence interval, 0.930–0.974). The ceiling effect of the K-FJS was 8.7% (n = 13), which was lower than the WOMAC's ceiling effect (10%). There was no floor effect. The correlation coefficients with WOMAC and SF-36 (physical function) were 0.708 and 0.682, respectively, indicating good construct validity. However, its correlation with mental health subscale of SF-36 was low (r = 0.143). At 3 to 12 months after TKA, the standardized response mean (SRM) was 0.67, which was lower than the SRM of WOMAC (1.03) obtained in the same period. The K-FJS demonstrated strong measurement properties in terms of good construct validity and reliability.

Conclusions

This study suggests that the K-FJS is an excellent instrument that can be used to monitor clinical outcomes after TKA. Using this standardized K-FJS, it would be possible for medical institutions to share more accurate clinical results.

Preoperative morbidity and joint awareness while awaiting hip arthroscopy for femoroacetabular impingement

Purpose

The Forgotten Joint Score (FJS-12) is a valid tool in the evaluation of patients undergoing hip arthroscopy, assessing the unique concept of joint awareness in the setting of a patient’s hip pathology. The preoperative burden on patients’ mental wellbeing of impaired joint function or symptoms is well established. The purpose of this study was to determine patients’ awareness of their hip joint whilst awaiting hip arthroscopy for femoroacetabular impingement, to explore any association between joint awareness and mental health status, and to determine whether this relates to time spent waiting for arthroscopy preoperatively.

Methods

A prospective database of patients undergoing hip arthroscopy between January 2018 and November 2020 was analysed. All patients with a diagnosis of femoroacetabular impingement (FAI) undergoing arthroscopic treatment were included. Questionnaires included the FJS-12, twelve item international hip outcome tool (iHOT-12), EuroQol 5D-5L (EQ-5D-5L) and the Tegner activity score. Pearson’s correlation coefficient was used to assess relationships between continuous variables.

Results

Preoperative functional outcomes were completed by 81 patients (97.5%) prior to undergoing hip arthroscopy. Median preoperative FJS-12 score was 16.67 (IQR 8.33 – 29.68). Forty-four patients reported any level of anxiety/depression preoperatively (54.3%). Preoperative FJS-12 showed a significant negative correlation with worsening mental health status (r = − 0.359, p <  0.001), and a significant positive correlation with EQ-5D-5L (r = 0.445, p <  0.001). The duration of symptoms or time on the waiting list did not correlate with increased joint awareness or worsened mental health.

Conclusion

Joint awareness is high when awaiting hip arthroscopy for FAI. Increasing levels of joint awareness correlate with poorer mental health status and poorer quality of life measures, however these parameters do not seem to be associated with increased duration of symptoms prior to surgery or time on the waiting list for surgery.

Changes and thresholds in the Forgotten Joint Score after total hip arthroplasty : minimal clinically important difference, minimal important and detectable changes, and patient-acceptable symptom state

AIMS

The aim of this study was to identify the minimal clinically important difference (MCID), minimal important change (MIC), minimal detectable change (MDC), and patient-acceptable symptom state (PASS) in the Forgotten Joint Score (FJS) according to patient satisfaction six months following total hip arthroplasty (THA) in a UK population.

METHODS

During a one-year period, 461 patients underwent a primary THA and completed preoperative and six-month FJS, with a mean age of 67.2 years (22 to 93). At six months, patient satisfaction was recorded as very satisfied, satisfied, neutral, dissatisfied, or very dissatisfied. The difference between patients recording neutral (n = 31) and satisfied (n = 101) was used to define the MCID. MIC for a cohort was defined as the change in the FJS for those patients declaring their outcome as satisfied, whereas receiver operating characteristic curve analysis was used to determine the MIC for an individual and the PASS. Distribution-based methodology was used to calculate the MDC.

RESULTS

Using satisfaction as the anchor, the MCID for the FJS was 8.1 (95% confidence interval (CI) 3.7 to 15.9; p = 0.040), which was affirmed when adjusting for confounding. The MIC for the FJS for a cohort of patients was 17.7 (95% CI 13.7 to 21.7) and for an individual patient was 18. The MDC90 for the FJS was eight, meaning that 90% of patients scoring more than this will have experienced a real change that is beyond measurement error. The PASS threshold for the FJS was defined as 29.

CONCLUSION

The MCID and MIC can be used respectively to assess whether there is a clinical difference between two groups, or whether a cohort or patient has had a meaningful change in their FJS. Both values were greater than measurement error (MDC90), suggesting a real change. The PASS threshold for the postoperative FJS can be used as a marker of achieving patient satisfaction following THA. Cite this article: Bone Joint J 2021;103-B(12):1759-1765.

Clinical Course of Pain and Function Following Total Knee Arthroplasty: A Systematic Review and Meta-Regression

BACKGROUND

Total knee arthroplasty (TKA) is widely considered a successful intervention for osteoarthritis and other degenerative knee diseases. This study addresses the need for a high-quality meta-analysis that outlines the clinical course of pain and function post-TKA.

METHODS

The review included prospective cohort studies assessing pain or function of patients undergoing primary TKA at baseline (preoperatively) and at least 2 additional time points including one at least 12 months postoperatively. Two reviewers independently screened references, extracted data, and assessed risk of bias using the Quality in Prognosis Studies tool. The time course of recovery of pain and function was modeled using fractional polynomial meta-regression.

RESULTS

In total, 191 studies with 59,667 patients were included, most with low risk of bias. The variance-weighted mean pain score (/100, 0 = no pain) was 64.0 (95% confidence interval [CI] 60.2-67.7) preoperatively, 24.1 (95% CI 20.3-27.9) at 3 months, 20.4 (95% CI 16.7-24.0) at 6 months, and 16.9 (95%CI 13.6-20.3) at 12 months, and remained low (10.1; 95% CI 4.8-15.4) at 10 years postoperatively. The variance-weighted mean function score (/100, 0 = worst function) was 47.1 (95% CI 45.7-48.4) preoperatively, 72.8 (95% CI 71.3-74.4) at 3 months, 76.3 (95% CI 74.7-77.8) at 6 months, and 78.1 (95%CI 76.4-79.7) at 12 months. Function scores were good (79.7; 95% CI 77.9-81.5) at 10 years postoperatively.

CONCLUSION

Patients undergoing primary TKA can expect a large and rapid but incomplete recovery of pain and function in the first postoperative year. At 10 years, the gains in pain scores may still remain while there is an improvement in function.

Translation, cross-cultural adaptation, reliability and construct validity of the Dutch Oxford Knee Score - Activity and Participation Questionnaire

Background

Patients undergoing total knee arthroplasty (TKA) tend to be younger and tend to receive TKA at an earlier stage compared to 20 years ago. The Oxford Knee Score – Activity and Participation (OKS-APQ) questionnaire evaluates higher levels of activity and participation, reflecting activity patterns of younger or more active people. The purpose of this study was to translate the OKS-APQ questionnaire into Dutch, and to evaluate its measurement properties in pre- and postoperative TKA patients.

Methods

The OKS-APQ was translated and adapted according to the forward–backward translation multi step approach and tested for clinimetric quality. Floor and ceiling effects, structural validity, construct validity, internal consistency and test–retest reliability were evaluated using COSMIN quality criteria. The OKS-APQ, the Oxford Knee Score (OKS), the Short Form-36 (SF-36), a Visual Analogue Scale (VAS) for pain and the Forgotten Joint Score (FJS) were assessed in 131 patients (72 preoperative and 59 postoperative TKA patients), and the OKS-APQ was administered twice in 50 patients (12 preoperative and 38 postoperative TKA patients), after an interval of minimal 2 weeks.

Results

Floor effects were observed in preoperative patients. Confirmatory factor analyses (CFA) indicated a good fit of a 1-factor model by the following indices: (Comparative Fit Index (CFI): 0.97, Tucker-Lewis Index (TLI): 0.96 and Standardized Root Mean Square Residual (SRMR): 0.03). Construct validity was supported as > 75% of the hypotheses were confirmed. Internal consistency (Cronbach α’s from 0.81 to 0.95) was good in the pooled and separate pre- and postoperative samples and test–retest reliability (Intraclass Correlation Coefficients (ICCs) from 0.63 – 0.85) were good in postoperative patients and moderate in preoperative patients. The standard Error of Measurements (SEMs) ranged from 8.5 – 12.2 and the Smallest Detectable Changes in individuals (SDC_ind) ranged from 23.5 – 34.0 (on a scale from 0 to 100).

Conclusions

Preliminary findings suggest that the Dutch version of the OKS-APQ is reliable and valid for a Dutch postoperative TKA patient sample. However, in a preoperative TKA sample, the OKS-APQ seems less suitable, because of floor effects and lower test–retest reliability. The Dutch version of the OKS-APQ can be used alongside the OKS to discriminate among levels of activity and participation in postoperative patients.

Reliability and validity of the Hebrew version of the forgotten joint score for assessing the outcomes of total knee arthroplasty

Background

This prospective study aimed to assess the reliability and validity of the Hebrew version of the forgotten joint score-12 in patients undergoing total knee arthroplasty, because it is going to be used in the Hebrew-speaking populations in Israel.

Methods

The English version of forgotten joint score-12 was translated into Hebrew version by using the standard procedures and in collaboration with its authors. The consecutive patients who had undergone total knee arthroplasty in a single hospital were asked to fill out the Hebrew version of forgotten joint score-12, Oxford knee score, Short Form 12, and visual analog scale. A random subgroup of 60 patients were then asked to fill out a second Hebrew version of forgotten joint score-12 at a minimum of 2-week interval. The reliability was assessed in terms of internal consistency, test-retest reliability and split-half reliability. The validity was measured in terms of the outcomes as mentioned above.

Results

A total of 102 patients participated in the study. The Hebrew version of forgotten joint score-12 showed high reliability. The internal consistency was excellent (Cronbachs’ α = 0.943) and test-retest reliability was high (Intraclass correlation = 0.97). The forgotten joint scores were correlated with the Oxford knee score, Short Form 12, and visual analog scale (r = 0.86, r = 0.72, and r=-0.8, respectively), indicating a high validity.

Conclusions

The Hebrew version of forgotten joint score-12 has excellent reliability, excellent test-retest reliability and good validity. It can be safely used for assessing outcomes of TKA.

Good Validity and High Internal Consistency of the Forgotten Joint Score-12 in Patients After Medial Opening Wedge High Tibial Osteotomy

BACKGROUND

The Forgotten Joint Score-12 (FJS-12) was originally developed to assess awareness of an artificial joint. Medial opening wedge high tibial osteotomy (MOWHTO), an alternative surgical method of knee replacement, is a joint-preservation surgery; therefore, joint awareness should be used to evaluate its clinical results. However, FJS-12 has not been validated as a tool to evaluate the postoperative results of MOWHTO. This study aimed to validate FJS-12 in MOWHTO.

METHODS

Patients with bilateral knee surgery, previous knee surgery, flexion contracture >15°, varus alignment >20°, and patients without plate removal surgery were excluded. Finally, 71 knees of 71 patients were analyzed, with a mean follow-up of 34.5 months. The FJS-12 score and Knee Injury and Osteoarthritis Outcome Score (KOOS) were obtained, and the floor and ceiling effect of each score was investigated. Cronbach's α was calculated to determine the internal consistency of FJS-12. Spearman's correlation coefficients between FJS-12 and KOOS were calculated to assess convergent validity.

RESULTS

There were ceiling effects in 3 KOOS subscales (symptoms [25.4%], pain [15.5%], and activities of daily living [25.4%]) but not in FJS-12 (8.5%). No floor effect was noted in any patient-reported outcome measures. The total Cronbach's α was 0.9457 in FJS-12. FJS-12 showed moderate-to-strong positive correlations with all KOOS subscales (r = 0.64-0.72).

CONCLUSION

FJS-12 showed a lower ceiling effect than KOOS and high internal consistency and convergent validity in patients following MOWHTO. With its low ceiling effect, FJS-12 was found to be useful for evaluating patients following MOWHTO.

Vitamin E-enriched polyethylene bearings are not inferior to Arcom bearings in primary total knee arthroplasty at medium-term follow-up

INTRODUCTION

The release of wear particles can be responsible for periprosthetic osteolysis, which can in turn, lead to aseptic loosening. Vitamin E-infused polyethylene (HXLPE Vit-E) has been shown, in vitro, to be more resistant to wear than conventional polyethylene (UHMWPE) by its crosslinking (HXLPE) and its higher resistance to oxidation. After reading a case report of a fracture of a vitamin E-enriched HXLPE bearing, the aim of this retrospective study was to evaluate fracture risk and clinical inferiority or not of vitamin-E HXLPE compared to conventional polyethylene in total knee arthroplasty (TKA).

MATERIALS AND METHODS

Three hundred and forty-nine patients (403 TKAs) were contacted, to find out whether they had undergone revision surgery for any reason after a mean (SD) of 7 (1.5) years. Follow-up control radiographs were analyzed for periprosthetic radiolucent lines (RLL) and loosening. Two different Patient Reported Outcome Measurements Scores (PROMS), KOOS and FJS-12, were utilized to assess the daily functionality and identify potential problems.

RESULTS

No statistically significant difference in revision rate, occurrence of aseptic loosening or RLL nor outcome as measured with PROMS was observed.

CONCLUSIONS

No bearing fractures or clinical inferiority was observed for vitamin E-enriched HXLPE at medium-term follow-up (7 years) compared to conventional Arcom polyethylene.

LEVEL OF EVIDENCE

Level III, therapeutic study.

Meaningful values in the Forgotten Joint Score after total knee arthroplasty

AIMS

The aim of this study was to identify the minimal clinically important difference (MCID), minimal important change (MIC), minimal detectable change (MDC), and patient-acceptable symptom state (PASS) threshold in the Forgotten Joint Score (FJS) according to patient satisfaction six months following total knee arthroplasty (TKA).

METHODS

During a one-year period 484 patients underwent a primary TKA and completed preoperative and six-month FJS and OKS. At six months patients were asked, "How satisfied are you with your operated knee?" Their response was recorded as: very satisfied, satisfied, neutral, dissatisfied, or very dissatisfied. The difference between patients recording neutral (n = 44) and satisfied (n = 153) was used to define the MCID. MIC for a cohort was defined as the change in the FJS for those patients declaring their outcome as satisfied, whereas receiver operating characteristic curve analysis was used to determine the MIC for an individual and the PASS threshold. Distribution-based methodology was used to calculate the MDC.

RESULTS

Using satisfaction as the anchor question, the MCID for the FJS was 16.6 (95% confidence interval (CIs) 8.9 to 24.3; p < 0.001) and when adjusting for confounding this decreased to 13.7 points (95% CI 4.8 to 22.5; p < 0.001). The MIC for the FJS for a cohort of patients was 17.7 points and for an individual patient was 10 points. The MDC90 for the FGS was 12 points; where 90% of patients scoring more than this will have experienced a real change that is beyond measurement error. The PASS was defined as 22 points or more in the postoperative FJS.

CONCLUSION

The estimates for MCID and MIC can be used to assess whether there is clinical difference between two groups and whether a cohort/patient has had a meaningful change in their FJS, respectively. The MDC90 of 12 points suggests a value lower than this may fall within measurement error. A postoperative FJS of 22 or more was predictive of achieving PASS. Cite this article: Bone Joint J 2021;103-B(5):846-854.

The ceiling effects of patient reported outcome measures for total knee arthroplasty

BACKGROUND

Patient reported outcome measurements (PROMs) that exhibit a substantial ceiling effect show clustering of participant's scores towards the upper limit of a scale and consequently have low discriminatory power among high end scores. This study aimed to compare ceiling effects at 1 and 2 years postoperatively across commonly usedPROMs for TKA.

HYPOTHESIS

We hypothesized, that the analyzed PROMs differ substantially in regards to their ceiling effect.

PATIENTS AND METHODS

Patients that underwent a primary unilateral TKA and completed pre-operative and post-operative questionnaires were included in the analysis. Participants completed the KOOS, KOOS-12, KOOS-JR, KOOS-PS, WOMAC and OKS preoperatively, and completed the KOOS, KOOS-12, KOOS-JR, KOOS-PS, WOMAC,OKS and FJS postoperatively at 1 and 2 years.

RESULTS

1-year and 2-year follow-up data was available for 380 and 193 patients, respectively. The preoperative mean age was 68.0 (8.5) and mean BMI was 31.4kg/m² (6.6), with a male to female ratio of 49.6% to 50.4%. At 1 year postoperatively, a ceiling effect was seen for the Pain and ADL subscales of the KOOS and the KOOS JR. The KOOS Pain, Symptoms, ADL and QoL subscales, the WOMAC Total and KOOS JR exhibited a ceiling effect at 2 years postoperatively. We found 9.0% and 14.8% of patients achieving a maximum score in the FJS at 1 and 2 years, respectively, indicating the absence of a substantial ceiling effect.

CONCLUSION

The PROMs studied differ substantially with regards to their ceiling effect and consequently their ability to detect differences between well performing groups. The KOOS Pain, Symptoms, ADL and QoL subscales, the WOMAC Total and KOOS JR exhibited a substantial ceiling effect at 2 years postoperatively. We recommend using PROMs like the FJS and KOOS-12 with a more evenly distribution of scores across the scale when studying well performing cohorts.

LEVEL OF EVIDENCE

III.

Good validity and reliability of forgotten joint score-12 in total knee arthroplasty in Hindi language for Indian population

PURPOSE

Commonly used patient-reported outcome measurement (PROM) tools for knee joint have a ceiling effect and may not be able to differentiate between patients achieving outcomes better than the upper limit of the score. Forgotten joint score-12 (FJS-12) is said to be free of this limitation. FJS-12 has been translated and validated in different languages. This study aims to translate and validate FJS-12 in Hindi (Hindi FJS-12).

METHODS

Hindi FJS-12 was tested for comprehensibility in a pilot study in 20 patients. This was followed by a prospective cohort study including 140 patients of bilateral total knee arthroplasty, with a minimum follow-up of 12 months. The mean age of the patients was 62.0 ± 14.5 years. There were 77 (55.2%) males and remaining were females. All patients were asked to fill up questionnaires of Hindi FJS-12, WOMAC, KSS and OKS. Hindi FJS-12 was tested for validity, reliability, responsiveness, floor effect and ceiling effect. Construct validity was expressed as the Pearson correlation coefficient. Internal consistency was expressed as Cronbach's alpha and test-retest reliability as the intra-class correlation coefficient (ICC).

RESULTS

In the pilot study, it was seen that all the questions were well answered by most of the participants. The main study showed good construct validity with Hindi FJS-12 showing moderate correlation with WOMAC, KSS and OKS (Pearson coefficients 0.45, 0.32, 0.37, respectively). Hindi FJS-12 had excellent internal consistency with Cronbach's alpha of 0.93 (95% CI 0.90, 0.97). ICC was 0.95 (95% CI 0.90, 0.99). No floor or ceiling effect was observed.

CONCLUSION

Hindi FJS-12 has high validity, reliability and reproducibility for knee function after TKA. It is devoid of floor or ceiling effect. Thus, it can be successfully used for studying knee function in the Indian population.

LEVEL OF EVIDENCE

Prospective cohort study, Level II.

Unicompartmental Knee Arthroplasty: Minimal Important Difference and Patient Acceptable Symptom State for the Forgotten Joint Score

Background and Objectives: Unicompartmental knee arthroplasty (UKA) is a valid alternative to total knee arthroplasties (TKAs) in selected cases. After surgery, patients' experience and satisfaction were traditionally evaluated by pre- and postsurgical scores and Patient-Reported Outcome Measures (PROMs). Otherwise, a statistically significant change does not necessarily correlate to a clinically meaningful improvement when measured using PROMs. To evaluate the real effect of a specific treatment and understand the difference between groups in a clinical trial, it is necessary to use a meaningful quantum of change on the score assessed. The minimal clinically important difference (MCID) and the Patient Acceptable Symptom State (PASS) can provide this meaningful change. This paper aimed to calculate the MCID and the PASS of the Forgotten Joint Score (FJS-12) after UKA. Materials and Methods: A total of 40 patients with a mean age 72.5 ± 6.4 years undergoing UKA were assessed preoperatively and six months postsurgery using the FJS-12 and the Oxford Knee Score (OKS). The baseline and 6-month postoperative scores were compared using the Wilcoxon signed ranks test. The correlation was calculated with Spearman's rho. Both distribution-based approaches and anchor approaches were used to estimate MCID for the FJS-12. The 75th percentile and the Receiver operating characteristic (ROC) curve methods were used to calculate the PASS of FJS-12. Results: MCID estimates for normalized FJS-12 for UKA ranged from 5.68 to 19.82. The threshold of the FJS-12 with ROC method was 72.92 (AUC = 0.76). The cut-off value computed with the 75th percentile approach was 92.71. Conclusions: The MCID and PASS represent valid tools to assess the real perception of clinical improvement in patients who underwent UKA. The MCID value of FJS-12 was 12.5 for patients who underwent UKA. The value of the PASS for the FJS-12 in patients who underwent UKA was 72.92.