Predictors of moderate-severe functional limitation 2 and 5 years after revision total knee arthroplasty

A mapping review on preoperative prognostic factors and outcome measures of revision total knee arthroplasty

To map literature on prognostic factors related to outcomes of revision total knee arthroplasty (rTKA), to identify extensively studied factors and to guide future research into what domains need further exploration. We performed a systematic literature search in MEDLINE, Embase, and Web of Science. The search string included multiple synonyms of the following keywords: "revision TKA", "outcome" and "prognostic factor". We searched for studies assessing the association between at least one prognostic factor and at least one outcome measure after rTKA surgery. Data on sample size, study design, prognostic factors, outcomes, and the direction of the association was extracted and included in an evidence map. After screening of 5,660 articles, we included 166 studies reporting prognostic factors for outcomes after rTKA, with a median sample size of 319 patients (30 to 303,867). Overall, 50% of the studies reported prospectively collected data, and 61% of the studies were performed in a single centre. In some studies, multiple associations were reported; 180 different prognostic factors were reported in these studies. The three most frequently studied prognostic factors were reason for revision (213 times), sex (125 times), and BMI (117 times). Studies focusing on functional scores and patient-reported outcome measures as prognostic factor for the outcome after surgery were limited (n = 42). The studies reported 154 different outcomes. The most commonly reported outcomes after rTKA were: re-revision (155 times), readmission (88 times), and reinfection (85 times). Only five studies included costs as outcome. Outcomes and prognostic factors that are routinely registered as part of clinical practice (e.g. BMI, sex, complications) or in (inter)national registries are studied frequently. Studies on prognostic factors, such as functional and sociodemographic status, and outcomes as healthcare costs, cognitive and mental function, and psychosocial impact are scarce, while they have been shown to be important for patients with osteoarthritis.

Management of Gonarthrosis with a Rotating Hinge Prosthesis: Minimum 10-Year Follow-up

BACKGROUND

The use of hinged designs is usually reserved for severe deformities or instability in contemporary total knee arthroplasty (TKA). Results have been mixed with some authors reporting relatively high incidences of complications. The aim of this study is to present the results of primary TKA performed with a hinged prosthesis with a minimum 10-year follow-up. We also examined the factors that influence survivorship of this prosthesis.

METHODS

A total of 238 primary TKA procedures were performed using hinged prostheses. Indications included osteoarthritis, rheumatoid arthritis, posttraumatic deformity, and arthritis. Clinical outcomes were assessed using the Hospital for Special Surgery score. Radiologic assessment was performed at each follow-up. Survivorship was calculated based on the Kaplan-Meier method. All complications were documented.

RESULTS

Mean follow-up was 13.5 years (standard deviation [SD], 3.4). Mean flexion at final review was 118° (SD, 20°). Fifty-four percent and 20% reported excellent and good functional scores, respectively. Survivorship was 94% at 13.5 years in patients over 60 years of age and 77% in patients less than 60 years of age. Survivorship in patients with preoperative varus deformity was 96% and that in valgus knees was 79%.

CONCLUSIONS

The results of this study suggest that when rotating hinges are used for primary TKA, the best results are achieved in patients over 60 years old. The indications for this design in the setting of primary TKA include significant deformities, severe bone loss, and ligamentous laxity.

Patient-Reported Outcome Measures (Pain, Function, and Quality of Life) After Aseptic Revision Total Knee Arthroplasty

BACKGROUND

Despite the growing frequency of revision total knee arthroplasty (rTKA), there is limited information regarding patient-reported outcome measures (PROMs) after that procedure. Therefore, the purpose of this study was to determine (1) PROM improvements in pain, function, quality of life (QOL), and global health and (2) predictors of PROMs for patients undergoing aseptic rTKA as determined using a multilevel model with patients nested within surgeons.

METHODS

A prospective cohort of 246 patients who underwent aseptic rTKA from January 2016 to December 2017 and had baseline and 1-year postoperative PROMs were analyzed. The most common surgical indications were aseptic loosening (n = 109), instability (n = 73), and implant failure (n = 64). The PROMs included in this study were the Knee injury and Osteoarthritis Outcome Score (KOOS)-Pain, -Physical Function Short Form (PS), and -Quality of Life (QOL) as well as the Veterans Rand-12 (VR-12) Physical Component Summary (PCS) and Mental Component Summary (MCS). Multivariable linear regression models with patients nested within surgeons were constructed for predicting change in PROMs from baseline to 1 year.

RESULTS

The mean 1-year postoperative improvements in the KOOS-Pain and PS PROMs were 30.3 and 19.15 points, respectively, for the overall rTKA series. Improvement in the KOOS-Pain was associated with older age, baseline arthrofibrosis, lower baseline pain, and non-Medicare/Medicaid insurance and worsening of the scores was associated with multiple prior surgical procedures and instability. Improvement in the KOOS-PS was associated with baseline arthrofibrosis and female sex and worsening was associated with limited baseline function, an instability diagnosis, multiple prior surgical procedures, and increased hospital length of stay (LOS). Overall, the mean KOOS-QOL improved by 29.7 points. Although the mean VR-12 PCS improved, 54.9% of the patients saw no clinical improvement. Additionally, only 31.3% of the patients reported improvements in the VR-12 MCS. A multilevel mixed-effects model with patients/operations nested within surgeons demonstrated that the differences in the surgeons' results were minimal and explained only ∼1.86%, ∼1.12%, and ∼1.65% of the KOOS-Pain, KOOS-PS, and KOOS-QOL variance that was not explained by other predictors, respectively.

CONCLUSIONS

Overall, patients undergoing aseptic rTKA had improvements in pain, function, and QOL PROMs at 1 year. Although overall QOL improved, other global-health PROMs remained unchanged. The associations highlighted in this study can help guide the preoperative clinical decision-making process by setting expectations before aseptic rTKA.

LEVEL OF EVIDENCE

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

Polymyositis has minimal effect on primary total knee or hip arthroplasty outcomes

To assess whether polymyositis is associated with more complications and higher healthcare utilization after total knee or hip arthroplasty (TKA/THA). Using the 1998-2014 U.S. National Inpatient Sample data, we performed multivariable-adjusted logistic regression analyses to assess the association of polymyositis with in-hospital complications (implant infection, revision, transfusion, mortality) and healthcare utilization (hospital charges, length of hospital stay, discharge to non-home setting), controlling for important covariates and confounders. Sensitivity analyses additionally adjusted the main models for hospital location/teaching status, bed size, and region. Of the 4,116,485 THAs and 8,127,282 TKAs, 853 people with polymyositis had THAs (0.02%) and 1038 had TKAs (0.01%). In multivariable-adjusted analyses, compared to people without polymyositis, people with polymyositis had similar odds of hospital charges above the median, hospital stay > 3 days, and discharge to non-home setting post-TKA and post-THA. Polymyositis was associated with significantly lower odds ratio (OR; 95% confidence interval [CI]) of revision and mortality post-THA, 0.44 (0.36, 0.55) and 0.63 (0.48, 0.84), but not post-TKA, 2.98 (0.47, 18.95) and 4.40 (0.61, 31.64), respectively. Findings from the main analyses were confirmed in the sensitivity analyses. People with polymyositis had no increase in healthcare utilization post-TKA/THA. A lower revision rate and mortality post-THA in people with polymyositis need further confirmation. Study findings should reassure the key stakeholders about the benefits of TKA/THA, including people with polymyositis.

[Predictors for persistent pain and dissatisfaction after total knee arthroplasty]

BACKGROUND

A substantial number of patients patients suffer from persistent pain or are unsatisfied after total knee arthroplasty (TKA).

OBJECTIVES

This work aims to present the frequency of postoperative persistent pain and/or dissatisfaction as well as known causes and predictors.

MATERIALS AND METHODS

The current literature is studied regarding the subject and is reviewed narratively.

RESULTS

Most postoperative problems did not arise from operation details, but from patient-related criteria, a lack of patient education and selection. The satisfaction correlates most strongly with the reduction of preoperative pain.

CONCLUSION

For a successful TKA, care should be taken that the following aspects are met preoperatively: clinically and radiologically advanced osteoarthritis, a patient age preferably older than 60 years, sufficient psychosocial resources to cope with postoperative stress, no opioid medication and realistic expectations after TKA. Postoperatively, patients with persistent pain or dissatisfaction should be checked for any prosthesis-related problems. If no prosthesis-related problems could be detected, the patients should be referred for interdisciplinary therapies.

Gender and Preoperative Function Predict Physical Activity Levels After Revision Total Knee Arthroplasty

BACKGROUND

The incidence of revision total knee arthroplasty (TKA) is projected to increase 6-fold worldwide by 2030. As the number of younger, physically active revision TKA patients increases in future, understanding factors influencing postoperative function will be increasingly important to help counsel patients. The primary aim of this study was to examine factors influencing return to physical activity following revision TKA.

METHODS

Patients who had undergone tibiofemoral revision between 2003 and 2013 at a single UK teaching hospital were retrospectively identified from a prospectively collected arthroplasty database. Preoperative activity level (University of California, Los Angeles [UCLA] score), patient demographics, indication, implant used, and Oxford Knee Scores (OKSs) were recorded in the database. At a mean follow-up of 3.9 years (standard deviation, 2.2), UCLA score, OKS, EuroQol-5 Dimension Score (EQ-5D), satisfaction, complications, and WORQ scores (Work, Osteoarthritis and Joint-Replacement Questionnaire) were sampled via postal questionnaire. Patient experience of complications and related surgery was also identified from healthcare records. Univariate and multivariate analyses were performed.

RESULTS

Responses were received from 112 revision TKAs (112 patients; mean age, 71 years). Mean UCLA activity scores improved from preoperative levels (P < .001): activity levels improved in 47% of patients with 58% engaging in moderate or more intensive activities (UCLA score ≥5). Postoperative activity level was independently predicted by male gender (P = .042) and preoperative UCLA score (P < .001). Increasing social deprivation was associated with inferior UCLA (P = .005), EQ-5D (P < .005), and OKS (P = .006) scores. Indication, implant type, and patient body mass index did not affect functional outcome or satisfaction (P > .05). Patients <65 years old were more likely to be dissatisfied (P = .009), and patients aged ≤55 years were more likely to report difficulties with WORQ criteria (P < .05).

CONCLUSION

Although 90% of patients maintain activity levels following revision TKA, less than half increase levels and this is predicted by male sex and pre-revision activity level.

Early complications of revision total knee arthroplasty in morbidly obese patients

INTRODUCTION

Morbid obesity is a known risk factor for complications and failure following primary total knee arthroplasty. Complications following revision total knee arthroplasty (rTKA) in the morbidly obese (BMI > 40) have not been well described. A retrospective cohort study was designed to investigate the early complications of rTKA in morbidly obese patients.

METHODS

Revision TKA procedures were performed between January 2009 and December 2012 at a single institution. Comparisons were made between patients with a normal BMI (18.5-25) and patients with morbid obesity (BMI > 40).

RESULTS

Thirty-three of 141 morbidly obese patients (23.4%) had a complication compared to 10 of 96 patients with a BMI 18.5-25 (10.4%) (p = 0.011). Morbidly obese patients were younger (69.3 vs. 61.4 years, p < 0.0001), and their most frequent complication in comparison with patients with normal BMI was wound healing problems (p = 0.01).

CONCLUSION

Morbidly obese patients are at a significantly increased rate of early complications following rTKA compared to a normal weight cohort, especially with regard to wound complications. The morbidly obese group was significantly younger at the time of rTKA. In addition, this study highlights the importance of risk stratification for morbidly obese patients undergoing rTKA.

Cemented conical stems can be removed more easily than cylindrical stems, regardless of cone angle in revision knee arthroplasty

BACKGROUND

According to literature, more than 30% of revised knee arthroplasties will require at least one re-revision. Practical experience has shown that there are considerable product-specific differences in the explantability of cemented long-stem prostheses. In the registers of successful implants, stem geometry varies considerably between the manufacturers. However, comparative data on explantability of the respective stems are missing. Objective of the present study was to identify a correlation between the geometry of a smooth cemented long stem and the necessary explantation energy required until failure of the implant-cement interface occurs.

METHODS

Eight cemented stems with different conical profile angles (0°-3°) were explanted in a reproducible biomechanical setup each six times to evaluate the correlation between the stem design and the required explantation energy.

RESULTS

The average explantation energy was highest in the case of the cylindrical stem, at 18.1 ± 3.6 J. At a cone angle of 0.25°, it was just 12.1 ± 2.1 J (p < 0.001) and dropped beyond 0.5° to an average of 5.7 ± 1.8 J (p < 0.001). Between 0.5° and 3°, no significant difference in the required extraction energy was observed.

CONCLUSIONS

Whereas smooth conical stems can mostly be removed easily, an early decision in favour of osteotomy or fenestration can be taken in the case of cylindrical cemented stems.

Periprosthetic Joint Infection Does Not Preclude Good Outcomes after a Revision Total Knee Arthroplasty: A 7-Year Follow-Up Study of 144 Retrospective Cases

Background and Purpose

Debate exists on whether septic revision total knee arthroplasty (TKA) results in inferior clinical outcomes, and limited information is available regarding the factors associated with such outcomes. This study aimed to (1) compare clinical outcomes and characteristics of aseptic versus septic revision TKA and (2) identify the risk factors associated with inferior clinical outcomes.

Methods

We retrospectively reviewed 144 revision TKAs (90 aseptic and 54 septic revisions) that were followed for a minimum of 3 years (mean = 7 years). Clinical outcome data, namely, Knee Society knee and function scores and the Hospital for Special Surgery knee score, were collected. We reviewed 13 pre- and intraoperative variables.

Results

Postoperative clinical outcomes were inferior in septic revision surgeries (p<0.05). In regression analyses, however, septic revision was not an independent risk factor for poor clinical outcomes. The independent risk factors for poor outcome were identified where Anderson Orthopedic Research Institute grade 3 femoral and tibial bone defects, more than three surgeries, and treatment for persistent infection were associated with inferior clinical outcomes (all p<0.05). Standard two-stage septic revision without grade 3 bone defects or additional surgeries showed comparable outcomes to aseptic revision.

Interpretation

Clinical outcomes of septic revision were inferior to those of aseptic revision. However, poor outcomes were mainly associated with large bone defects and an increased number of surgeries. The outcomes of aseptic and septic revision surgery were similar when patients with larger bone defects and more than three surgeries were excluded.

Bilateral Simultaneous Revision Total Knee Arthroplasty as a Single Staged Procedure: A Case Report and Review of Literature

Bilateral revision total knee arthroplasty (TKA) is a surgical procedure, which is rarely done simultaneously as it is a difficult surgery and the safety of simultaneous bilateral single stage surgery remains unknown. We report a case of a 67-year-old woman who presented to us with bilateral painful and unstable TKA (right > left) of six months duration. The primary bilateral TKA were done 14 years ago. Bilateral simultaneous revision TKA was performed, using cemented, constrained, long-stem prostheses. The intraoperative and postoperative periods remained uneventful. At last follow-up at four years, she had a pain-free range of motion of up to 0-115°, and the patient had returned to the activities of daily living. She had stable knees with good function and no evidence of loosening or wear.

Psychosocial Risk Factors for Postoperative Pain in Ankle and Hindfoot Reconstruction

BACKGROUND

The purpose of this study was to examine factors associated with pain after elective ankle and hindfoot reconstruction.

METHODS

Patients who underwent major ankle or hindfoot reconstruction over a 3-year period were identified. Retrospective chart review determined patient demographics, comorbidities, surgeries, tobacco, alcohol, and narcotic use, chronic pain, and mood disorders. Primary outcomes were cumulative amount of narcotic prescribed (morphine milligram equivalent dose) in the initial 90-day postoperative period, beyond 90 days, and visual analog pain score (VAS) at a minimum of 1-year follow-up. One hundred thirty-two patients (139 operations) met the inclusion criteria.

RESULTS

The average narcotic amount prescribed in the initial 90 days after surgery was 1711 mg (morphine equivalent), and narcotic prescriptions were required after 52 surgeries (35%) past 90 days. Preoperative narcotic use (P < .01), chronic pain disorder (P = .02), and mood disorder (P < .01) were significant risk factors for continued narcotic use past 90 days. Tobacco use (P = .01) and chronic pain disorder (P < .01) also were significant risk factors for increased initial postoperative narcotic use. The average VAS score in 91 patients at an average of 2.7-year follow-up was 2.1. Mood disorder was a risk factor for increased VAS (P < .01). No other associations were noted.

CONCLUSION

Patients being treated for chronic pain, diagnosed with a mood disorder, taking any amount of narcotics preoperatively, or using tobacco products had a statistically significant increased risk for pain postoperatively. The presence of risk factors should prompt physicians to discuss pain management strategies before surgery.

LEVEL OF EVIDENCE

Level III, comparative series.

Residual Symptoms and Function in Young, Active Hip Arthroplasty Patients: Comparable to Normative Controls?

BACKGROUND

Whether patient-reported symptoms and function after total hip and surface replacement arthroplasty in young, active patients compare favorably to those without known hip pathology has not been investigated.

METHODS

A retrospective, multicenter study was designed in which 5 centers contributed patients aged <60 years with a presymptomatic University of California at Los Angeles score ≥6 undergoing hip arthroplasty. Data were collected by an independent, third-party survey center that administered a questionnaire assessing patient satisfaction and function. A "control" population with no prior hip interventions or hip pathology limiting their activity, that met the age and activity criteria, was identified for comparison using multivariate regression analyses.

RESULTS

Eight-hundred six hip arthroplasties (682 total hip arthroplasty, 124 surface replacement arthroplasty) and 158 controls were included. A greater percentage of hip arthroplasty patients were male and aged >50 years which was controlled during multivariate regression analyses. Control patients reported the presence of a limp (15%), stiffness (11%), and pain in the hip (8%), but to a lesser degree than hip arthroplasty patients. Control patients were less likely to report pain in the hip (odds ratio [OR] = 0.4, 95% confidence interval [CI] = 0.2-0.7, P = .006), stiffness in the hip (OR = 0.5, 95% CI = 0.3-0.8, P = .02), and a limp (OR = 0.5, 95% CI = 0.3-0.8, P < .001) vs patients undergoing hip arthroplasty.

CONCLUSION

When interviewed by an independent third party, a substantial portion of control patients did note the presence of hip symptoms, but to a lesser degree than young, active patients undergoing hip arthroplasty.

Men and Women Demonstrate Differences in Early Functional Recovery After Total Knee Arthroplasty

OBJECTIVE

To investigate whether sex affects the trajectory of functional recovery after total knee arthroplasty (TKA).

DESIGN

Retrospective analysis from a historical database containing data from 3 prospective clinical trials and a pilot study.

SETTING

Clinical laboratory setting.

PARTICIPANTS

Recruitment across studies was restricted to patients who underwent an elective unilateral TKA for the treatment of osteoarthritis and were between 50 and 85 years of age (N=301).

INTERVENTIONS

Across all 4 studies, patients received a TKA and physical therapy intervention. Measures of physical function and strength were assessed before TKA and 1, 3, and 6 months after TKA.

MAIN OUTCOME MEASURES

Using a repeated-measures maximum likelihood model, statistical inference was made to estimate the changes in outcomes from before surgery to 1, 3, and 6 months after TKA that were stratified by sex. Muscle strength was assessed during maximal isometric quadriceps and hamstrings contractions. Muscle activation was assessed in the quadriceps muscle. Physical function outcomes included timed Up and Go (TUG) test, stair climbing test, and 6-minute walk test (6MWT).

RESULTS

Women demonstrated less decline in quadriceps strength than did men at 1, 3, and 6 months after TKA (P<.04), whereas women demonstrated less decline in hamstrings strength 1 month after TKA (P<.0001). Women demonstrated a greater decline than did men on the TUG test (P=.001), stair climbing test (P=.004), and 6MWT (P=.001) 1 month after TKA. Sex differences in physical function did not persist at 3 and 6 months after TKA.

CONCLUSIONS

Sex affected early recovery of muscle and physical function in the first month after TKA. Women demonstrated better preservation of quadriceps strength but a greater decline on measures of physical function than did men.

The impact of custom cutting guides on patient satisfaction and residual symptoms following total knee arthroplasty

BACKGROUND

Custom cutting guides (CCGs) in total knee arthroplasty (TKA) use preoperative three-dimensional (3-D) imaging to manufacture cutting blocks specific to a patient's anatomy. The purpose of this study was to evaluate the impact of CCGs versus standard intramedullary and extramedullary guides on patient-reported satisfaction and residual symptoms following TKA.

METHODS

A retrospective, multicenter study was performed to compare a magnetic resonance imaging-based CCG system versus standard instrumentation. All patients received the same, cemented, fixed-bearing, cruciate-retaining component, and had a primary diagnosis of osteoarthritis. Data was collected by an independent, third party survey center blinded to surgical technique that administered telephone questionnaires assessing patient satisfaction and symptoms. Patient age, gender, minority status, education level, income, length of follow-up, and pre-arthritic UCLA scores were considered potential confounders and accounted for using multivariate logistic regression analyses.

RESULTS

448 patients (107 CCGs, 341 standard) were successfully interviewed. At a mean follow-up of threeyears, there was no difference in percentage of patients reporting their knee to feel "normal" (74% CCG versus 78% standard, p=0.37). Residual symptoms including knee stiffness (37% CCG versus 28% standard, p=0.08) and difficulty getting in and out of car (34% CCG versus 30% standard, p=0.40) remained high. Multivariate regression analyses demonstrated no differences between the two cohorts for both patient-reported satisfaction and residual symptoms (odds ratios 0.72 to 1.48; p=0.10 to 0.81).

CONCLUSION

When interviewed by an independent, blinded third party, the use of CCGs in TKA did not improve patient-reported satisfaction or residual symptoms versus the use of standard alignment guides.

The impact of joint line restoration on functional results after hinged knee prosthesis

BACKGROUND

Hinged knee prosthesis is an effective treatment method as a salvage procedure in marked ligamentous insufficiency and severe bone defects. Joint line determination and restoration are difficult due to large bone defects and distorted anatomy. We evaluated the impact of joint line alteration on the outcome in rotating hinge knee arthroplasty (RHKA).

MATERIALS AND METHODS

35 patients who had rotating hinged knee prosthesis applied between 2008 and 2013 were evaluated in this retrospective study. The patients were studied radiologically and clinically. Five patients were lost to followup and two patients died, leaving a total of 28 (7 male, 21 female) patients for final evaluation. The average age of the patients was 66.19 ± 8.35 years (range 52-83 years). The patients were evaluated clinically with Knee Society knee and functional score and patellar score. The joint line positions were evaluated radiographically with femoral epicondylar ratio method. The outcomes were also evaluated according to age, body weight and gender. Student's t-test, independent t-test, and the Wilcoxon signed rank test were used in the statistical analysis.

RESULTS

The mean Knee Society knee and functional score significantly improved from preoperative 19.52 ± 11.77 and 12.5 ± 15.66 respectively to 72.46 ± 14.01 and 70.36 ± 9.22 respectively postoperatively (P < 0.001). The mean range of motion of the knee improved from 55.95° ± 25.08° preoperatively to 92.14° ± 13.47° postoperatively (P < 0.001). Joint line position was restored in 20 patients (71.4%). Joint line alteration did not affect Knee Society Scores (KSSs) in contrast to patellar scores. Additionally, KSS was better in the patients with body mass index ≤30 at followup (P = 0.022 and P = 0.045).

CONCLUSION

RHKA is an effective salvage procedure for serious instability and large bone defects. Restoration of the joint line improves the patellar score although it had no effect on the clinical outcome.

Outcomes after Total Knee Arthroplasty for post-traumatic arthritis

INTRODUCTION

Total Knee Arthroplasty (TKA) is an important treatment for posttraumatic arthritis (PTA), but evidence on outcomes is sparse. The purpose of this study was to evaluate the impact of PTA versus primary osteoarthritis (OA) on postoperative outcomes after TKA.

METHODS

We queried the entire Medicare database from 2005 to 2012. International Classification of Diseases, 9th revision and Current Procedural Terminology codes were used to identify the procedure, indication, and complications. Patients with minimum two-years follow-up were selected. Odds ratios (ORs), confidence intervals, and p-values (p) were calculated.

RESULTS

For PTA, 3509 patients had TKA. For OA, 257,611 patients with TKA served as controls. The average Charlson Comorbidity Index for both groups was five. PTA patients were younger; only eight out of 29 Elixhauser comorbidities were higher. PTA patients had higher incidence of periprosthetic infection (OR 1.72, p<0.001), cellulitis or seroma (OR 1.19, p<0.001), knee wound complications (OR 1.80, p<0.001), TKA revision (OR 1.23, p=0.01), and arthrotomy/incision and drainage (OR 1.55, p<0.001). Blood transfusion rate was lower in PTA patients. There were no significant differences in bleeding complications, prosthetic dislocation, broken prostheses, periprosthetic fracture, osteolysis and polywear, neurovascular injury, and extensor mechanism rupture.

DISCUSSION AND CONCLUSION

This study represents, to our knowledge, TKA outcomes in the largest cohort of PTA patients to date. Our findings indicate that these patients are at higher risk for many, but not all, postoperative surgical complications despite being as healthy as patients receiving TKA for primary OA.

Stemmed femoral implants show lower failure rates in revision total knee arthroplasty

BACKGROUND

Stemmed femoral implants are not universally used in revision total knee arthroplasty. The aim of this study was to evaluate whether the re-revision rate would be greater for revision total knees performed without stemmed femoral implants compared with revision total knees performed with stemmed femoral implants.

METHODS

All revision cases performed at a single institution between 2004 and 2011 were retrospectively reviewed. A total of 130 revision total knee arthroplasty procedures (63 Group 1; 67 Group 2) met the inclusion criteria.

RESULTS

Revisions performed without femoral stems failed more often than revisions with femoral stems (44% vs 9%, p<0.001) despite more severe pre-operative bone loss in groups that were revised with stems (p<0.05).

CONCLUSIONS

We recommend that femoral stems be used routinely in procedures where a femoral implant is revised following a prior total knee arthroplasty.

Effect of preoperative neuromuscular training (NEMEX-TJR) on functional outcome after total knee replacement: an assessor-blinded randomized controlled trial

Background

Improving functional status preoperatively through exercise may improve postoperative outcome. Previous knowledge on preoperative exercise in knee osteoarthritis is insufficient. The aim of the study was to compare the difference in change between groups in lower extremity function from baseline to 3 months after Total Knee Replacement (TKR) following a neuromuscular exercise programme (NEMEX-TJR) plus a knee school educational package (KS) or KS alone.

Methods

45 patients (55–83 years, 53% male, waiting for TKR) were randomized to receive a minimum of 8 sessions of NEMEXTJR plus 3 sessions of KS or 3 sessions of KS alone. Function was assessed with the Chair Stand Test (CST, primary endpoint) and the Knee Injury and Osteoarthritis Outcome Score (KOOS) subscales focusing on daily living function (ADL) and pain (secondary endpoints). Assessments were performed immediately before and after the intervention, and at 6 weeks, 3 months and 12 months after surgery by a physiotherapist, blinded to group allocation.

Results

After intervention before surgery we observed a small improvement for primary and secondary endpoints in both groups, which did not differ significantly between groups: comparing the exercise to the control group the treatment effect for the CST was −1.5 seconds (95% CI: −5.3, 2.2), for KOOS ADL and KOOS pain the treatment effect was 1.3 points (−10.1, 12.8) and −2.3 (−12.4, 7.9) respectively. At 3 months after surgery we observed a small improvement in the primary endpoint in the control group and a significant improvement in the secondary endpoints in both exercise and control groups, which did not differ significantly between groups: comparing the exercise group to the control group the treatment effect in the CST was 2.0 seconds (−1.8, 5.8), for KOOS ADL and KOOS pain the treatment effect was −4.9 points (−16.3, 6.5) and −3.3 points (−13.5, 6.8) respectively.

Conclusions

A median (IQR) of 10 (8, 14) exercise sessions before surgery showed an additional small but non-significant improvement in all functional assessments compared to patient education alone. These benefits were not sustained after TKR. Our trial doesn’t give a conclusive answer to whether additional preoperative exercise on postoperative functional outcomes is beneficial.

Electronic supplementary material

The online version of this article (doi:10.1186/s12891-015-0556-8) contains supplementary material, which is available to authorized users.

The role of hinges in primary total knee replacement

The use of hinged implants in primary total knee replacement (TKR) should be restricted to selected indications and mainly for elderly patients. Potential indications for a rotating hinge or pure hinge implant in primary TKR include: collateral ligament insufficiency, severe varus or valgus deformity (>20°) with necessary relevant soft-tissue release, relevant bone loss including insertions of collateral ligaments, gross flexion-extension gap imbalance, ankylosis, or hyperlaxity. Although data reported in the literature are inconsistent, clinical results depend on implant design, proper technical use, and adequate indications. We present our experience with a specific implant type that we have used for over 30 years and which has given our elderly patients good mid-term results. Because revision of implants with long cemented stems can be very challenging, an effort should be made in the future to use shorter stems in modular versions of hinged implants.

New total knee arthroplasty designs: do young patients notice?

BACKGROUND

Although the volume of total knee arthroplasties (TKAs) performed in the United States continues to increase, recent reports have shown the percentage of patients who remain "unsatisfied" is as high as 15% to 30%. Recently, several newer implant designs have been developed to potentially improve patient outcomes.

QUESTIONS/PURPOSES

The purpose of this study was to determine the impact of high-flex, gender-specific, and rotating-platform TKA designs on patient satisfaction and functional outcomes.

METHODS

A four-center study was designed to quantify the degree of residual symptoms and functional deficits in patients undergoing TKA with newer implant designs compared with a 10-year-old, cruciate-retaining (CR) TKA system introduced in 2003. Each contributing surgeon was fellowship-trained and specialized in joint replacement surgery. Only patients younger than 60 years old were included. Data were collected by an independent, third-party survey center blinded to the implant type, who administered questionnaires about patient satisfaction, residual symptoms, function, and pre- and postoperative activity levels using previously published survey instruments. Two hundred thirty-seven CR, 137 rotating-platform, 88 gender-specific, and 65 high-flex TKAs were included in the analysis. Differences in baseline demographic variables were accounted for using multiple logistic regression statistical analyses.

RESULTS

Patients who received certain newer designs reported more residual symptoms (grinding, popping, and clicking) in the 30 days before survey administration than the group receiving a 10-year-old CR design (CR, 24% [57 of 237 patients] versus gender-specific, 36% [32 of 88 patients]; odds ratio [OR], 2.1; 95% confidence interval [CI], 1.1-3.8; p=0.03; and rotating-platform, 43% [59 of 137 patients]; OR, 2.2; 95% CI, 1.3-3.7; p<0.001). They also reported more functional problems, including getting in and out of a chair (CR, 19% [46 of 237 patients] versus gender-specific, 37% [32 of 88 patients]; OR, 1.0; 95% CI, 1.1-3.5; p=0.001). Patients with newer TKA designs did not demonstrate any improvements in function or patient satisfaction versus those who received the 10-year-old CR design.

CONCLUSIONS

When interviewed by an independent, blinded third party, the use of newer implant designs did not improve patient satisfaction and the presence of residual symptoms when compared with patients who received the 10-year-old CR design. Future studies should prospectively determine whether the purported benefits of newer implant designs improve patient-perceived outcomes.

LEVEL OF EVIDENCE

Level III, therapeutic study. See Guidelines for Authors for a complete description of levels of evidence.

Are outcomes after total knee arthroplasty worsening over time? A time-trends study of activity limitation and pain outcomes

Background

To examine whether function and pain outcomes of patients undergoing primary total knee arthroplasty (TKA) are changing over time.

Methods

The Mayo Clinic Total Joint Registry provided data for time-trends in preoperative and 2-year post-operative activity limitation and pain in primary TKA patients from 1993-2005. We used chi-square test and analysis for variance, as appropriate. Multivariable-adjusted analyses were done using logistic regression.

Results

In a cohort of 7,229 patients who underwent primary TKA during 1993-2005, mean age was 68.4 years (standard deviation (SD), 9.8), mean BMI was 31.1 (SD, 6.0) and 55% were women. Crude estimates showed that preoperative moderate-severe overall limitation were seen in 7.3% fewer patients and preoperative moderate-severe pain in 2.7% more patients in 2002-05, compared to 1992-95 (p < 0.001 for both). At 2-years, crude estimates indicated that compared to 1992-95, moderate-severe post-TKA overall limitation was seen in 4.7% more patients and moderate-severe post-TKA pain in 3.6% more patients in 2002-05, both statistically significant (p ≤ 0.018) and clinically meaningful. In multivariable-adjusted analyses that adjusted for age, sex, anxiety, depression, Deyo-Charlson index, body mass index and preoperative pain/limitation, patients had worse outcomes 2-year post-TKA in 2002-2005 compared to 1993-95 with an odds ratio (95% confidence interval (CI); p-value) of 1.34 (95% CI: 1.02, 1.76, p = 0.037) for moderate-severe activity limitation and 1.79 (95% CI: 1.17, 2.75, p = 0.007) for moderate-severe pain.

Conclusion

Patient-reported function and pain outcomes after primary TKA have worsened over the study period 1993-95 to 2002-05. This time-trend is independent of changes in preoperative pain/limitation and certain patient characteristics.

Electronic supplementary material

The online version of this article (doi:10.1186/1471-2474-15-440) contains supplementary material, which is available to authorized users.

Patient dissatisfaction following total knee replacement

A national, multi-centre study was designed in which a questionnaire quantifying the degree of patient satisfaction and residual symptoms in patients following total knee replacement (TKR) was administered by an independent, blinded third party survey centre. A total of 90% of patients reported satisfaction with the overall functioning of their knee, but 66% felt their knee to be ‘normal’, with the reported incidence of residual symptoms and functional problems ranging from 33% to 54%. Female patients and patients from low-income households had increased odds of reporting dissatisfaction. Neither the use of contemporary implant designs (gender-specific, high-flex, rotating platform) or custom cutting guides (CCG) with a neutral mechanical axis target improved patient-perceived outcomes. However, use of a CCG to perform a so-called kinematically aligned TKR showed a trend towards more patients reporting their knee to feel ‘normal’ when compared with a so called mechanically aligned TKR

This data shows a degree of dissatisfaction and residual symptoms following TKR, and that several recent modifications in implant design and surgical technique have not improved the current situation.

Cite this article: Bone Joint J 2014;96-B(11 Suppl A):96–100.

Predictive factors for failure after total knee replacement revision

PURPOSE

We used the Optetrak Condylar Constrained (CCK) implant, a modular and constrained knee implant as replacement for a failed primary arthroplasty, to assess the survivorship, the complications, the clinical, radiological, and functional situation, and the quality of life of those patients in whom a CCK had been implanted in recent years in order to find predictive pre-operative conditions of survival and clinical outcomes.

METHODS

We performed a retrospective study of 125 CCK implanted between 1999 and 2005. The mean follow-up was nine years (range, seven to 13). Mean age was 73.6 years. A total of 78% of the revised TKA were cemented and 66% were CR. We assessed the pre-operative, the operative and the postoperative conditions studying the medical files of all the patients. In order to study the functional and clinical situation we used the Hospital for Special Surgery (HSS) score and the Knee Society score (KSS), both clinical and functional. We analysed all the X-rays using the Knee Society Roentgenographic evaluation. The quality of life was studied using the Oxford knee score (OKS).

RESULTS

The mean results of the KSS clinical and the KSS functional were 68.24 and 63.85, respectively. There were not any conditions associated with poor results of the knees (p > 0.05). The global survival at 24 months was 92.7%, at 60 months 87.8% and at 96 months it was 87.8%. There were some conditions associated with poor survival of the knees, e.g. patients were younger than 70 years old, rheumatic diseases, kidney faliure, tibial tuberosity osteotomy, PS primary arthroplasty, revision before five years and septic loosening.

CONCLUSIONS

Based on these results there are some pre-operative factors that change the survival of the total knee replacement revision.

Better functional and similar pain outcomes in osteoarthritis compared to rheumatoid arthritis after primary total knee arthroplasty: a cohort study

OBJECTIVE

To determine the association of the underlying diagnosis with limitation in activities of daily living (ADL) and pain in patients undergoing primary total knee arthroplasty (TKA).

METHODS

Prospectively collected data from the Mayo Clinic Total Joint Registry were used to assess the association of diagnosis with moderate-severe limitation in ADL and moderate-severe pain at 2 and 5 years after primary TKA, using multivariable-adjusted logistic regression analyses. We calculated odds ratios (ORs) and 95% confidence intervals (95% CIs).

RESULTS

There were 7,139 primary TKAs at 2 years and 4,234 at 5 years. In multivariable-adjusted analyses, compared with rheumatoid arthritis (RA)/inflammatory arthritis, osteoarthritis (OA) was associated with significantly lower moderate-severe ADL limitation at 2 years (OR 0.5 [95% CI 0.3-0.8]) (P = 0.004) and at 5 years (OR 0.5 [95% CI 0.3-0.9]) (P = 0.02). There was no significant association of diagnosis of OA with moderate-severe pain at 2 years (OR 1.2 [95% CI 0.5-2.7]) (P = 0.68) or at 5 years (OR 1.0 [95% CI 0.3-3.7]) (P = 1.0).

CONCLUSION

We found that patients with OA who underwent primary TKA had better ADL outcomes compared to patients with RA/inflammatory arthritis at 2 and 5 years. On the other hand, the pain outcomes after primary TKA did not differ in OA versus RA. This suggests a discordant effect of underlying diagnosis on pain and function outcomes after TKA. These novel findings can be used to better inform both patients and surgeons about expected pain and function outcomes after primary TKA.

Predictors of pain medication use for arthroplasty pain after revision total knee arthroplasty

OBJECTIVE

Our objective was to study the use of pain medications for persistent knee pain and their predictors after revision total knee arthroplasty (TKA).

METHODS

We examined whether demographic (gender, age) and clinical characteristics [BMI, co-morbidity measured by the Deyo-Charlson index (a 5-point increase), anxiety and depression] predict the use of NSAIDs and narcotic pain medications 2 and 5 years after revision TKA. Multivariable logistic regression adjusted for these predictors as well as operative diagnosis, American Society of Anesthesiologists class and distance from the medical centre.

RESULTS

A total of 1533 patients responded to the 2-year questionnaire and 881 responded to the 5-year questionnaire. NSAID use was reported by 13.4% (206/1533) of patients at 2 years and 16.7% (147/881) at 5 years. Narcotic medication use was reported by 5.4% (83/1533) of patients at 2 years and 5.9% (52/881) at 5 years. Significant predictors of the use of NSAIDs for index TKA pain at 2 and 5 years were age >60-70 years [odds ratio (OR) 0.62 (95% CI 0.39, 0.98) and 0.46 (0.25, 0.85)] compared with age ≤60 years and a higher Deyo-Charlson index [OR 0.51 (95% CI 0.28, 0.93)] per 5-point increase at 5-year after revision TKA. Significant predictors of narcotic pain medication use for index TKA pain were age >60-70 years [OR 0.41 (0.21, 0.78)] and >70-80 years [0.40 (95% CI 0.22, 0.73)] at 2 years and depression [OR 4.58 (95% CI 1.58, 13.18)] at 5 years.

CONCLUSION

Younger age and depression were risk factors for the use of NSAIDs and narcotic pain medications for index TKA pain at 2- and 5-years after revision TKA.

Cerebrovascular disease is associated with outcomes after total knee arthroplasty: a US total joint registry study

We assessed the association of cerebrovascular disease preoperatively with patient-reported outcomes (PROs) of moderate-severe activity limitation and moderate-severe pain at 2- and 5-years after primary total knee arthroplasty (TKA) using multivariable-adjusted logistic regression; 7139 primary and 4234 revision TKAs were included. Compared to the patients without cerebrovascular disease, those with cerebrovascular disease had a higher odds ratio (OR) of moderate-severe limitation at 2 years and 5 years, 1.32 (95% confidence interval [CI]: 1.02, 1.72; P = .04) and 1.83 (95% CI: 1.32, 2.55; P < .001), respectively. No significant associations were noted with moderate-severe pain at 2 years or 5 years. In conclusion, we found that cerebrovascular disease is independently associated with pain and function outcomes after primary TKA. This should be taken into consideration when discussing expected outcomes of TKA with patients.

Diabetes: a risk factor for poor functional outcome after total knee arthroplasty

Background

To assess the association of diabetes with postoperative limitation of activities of daily living (ADLs) after primary total knee arthroplasty (TKA).

Methodology/Principal Findings

We used the prospectively collected data from the Mayo Clinic Total Joint Registry to assess the association of diabetes and diabetes with complications with moderate-severe ADL limitation 2- and 5-years after primary TKA. Multivariable logistic regression with general estimating equations adjusted for preoperative ADL limitation, comorbidity and demographic and clinical covariates. Odds ratio (OR) and 95% confidence interval (CI) are presented. 7,139 primary TKAs at 2-years and 4,234 at 5-years constituted the cohorts. In multivariable-adjusted analyses, diabetes was associated with higher odds of moderate-severe limitation at 2- and 5-years, 1.71 (95% CI: 1.26, 2.32; P = 0.001) and 1.66 (95% CI: 1.13, 2.46; P = 0.01). Respective ORs for patients with diabetes with complications were 2.73 (95% CI: 1.47, 5.07; P = 0.001) and 2.73 (95% CI: 1.21, 6.15; P = 0.016). Sensitivity analyses that adjusted for anxiety and depression or anxiety, depression and ipsilateral hip involvement showed minimal attenuation of magnitude of the association.

Conclusions/Significance

In this large study of patients who underwent primary TKA, diabetes as well as its severity were independently associated with poorer functional outcome. Given the increasing rates of both diabetes as well as arthroplasty, more insight is needed into disease-related and treatment-related factors that underlie this higher risk of ADL limitation in patients with diabetes. Poor functional outcomes may be preventable by modifying the control of diabetes and associated comorbidity in pre- and post-arthroplasty periods.

Underlying diagnosis predicts patient-reported outcomes after revision total knee arthroplasty

OBJECTIVE

To assess the association of underlying diagnosis with outcomes after revision total knee arthroplasty (TKA).

METHODS

For this cohort study we used prospectively collected data from the Mayo Clinic Total Joint Registry on all revision TKA patients from 1993 to 2005 with 2- or 5-year response to a validated knee questionnaire that assesses pain and function. We used logistic regression to assess the odds of moderate-severe activities of daily living (ADL) limitations and moderate-severe index knee pain 2 and 5 years after revision TKA. Odds ratios (ORs) and 95% CIs are presented.

RESULTS

The underlying diagnosis for the 2- and 5-year cohorts was loosening, wear or osteolysis in 73% and 75%; dislocation, bone or prosthesis fracture, instability or non-union in 17% and 15%; and failed prior arthroplasty with components removed or infection in 11% and 11%, respectively. In multivariable adjusted analyses that included preoperative status, compared with patients with loosening/wear/osteolysis, patients with dislocation/fracture/instability/non-union had an OR of 2.1 for moderate-severe ADL limitation (95% CI 1.3, 3.1, P < 0.001) and those with failed prior arthroplasty/infection had an OR of 1.1 (95% CI 0.6, 1.8, P = 0.4). At 5 years, differences were no longer significant. In multivariable adjusted analyses, compared with patients with loosening/wear/osteolysis, patients with dislocation/fracture/instability/non-union had an OR of 2.0 for moderate-severe pain (95% CI 1.3, 3.1, P < 0.01) at 2 years and an OR of 2.1 (95% CI 1.3, 3.8, P = 0.01) at 5 years. Failed prior arthroplasty/infection was not significantly different than the reference category.

CONCLUSION

Underlying diagnosis is independently associated with ADL limitations and pain after revision TKA. This information can help patients have realistic expectations of outcomes.

Patient-level improvements in pain and activities of daily living after total knee arthroplasty

OBJECTIVE

To study patient-level improvements in pain and limitations of key activities of daily living (ADLs) after primary or revision total knee arthroplasty (TKA).

METHODS

We analysed prospectively collected data from the Mayo Clinic Total Joint Registry for improvements in index knee pain severity and limitations in three key ADLs (walking, climbing stairs and rising from a chair) from pre-operative to 2 and 5 years post-TKA.

RESULTS

The primary TKA cohort consisted of 7229 responders pre-operatively, 7139 at 2 years and 4234 at 5 years post-operatively. The revision TKA cohort consisted of 1206 responders pre-operatively, 1533 at 2 years and 881 at 5 years post-operatively. In the primary TKA cohort, important pain reduction to mild or no knee pain at 2 years was reported by 92% with moderate pre-operative pain and 93% with severe pre-operative pain; respective proportions were 91% and 91% at 5 years follow-up. For revision TKA, respective proportions were 71% and 66% at 2 years and 68% and 74% at 5 years. Three per cent with no/mild pre-operative overall limitation and 19% with moderate/severe pre-operative overall limitation had moderate/severe overall activity limitation 2 years post-operatively; at 5 years the respective proportions were 4% and 22%. Respective proportions for revision TKA were up to 3% and 32% at 2 years and 4% and 34% at 5 years.

CONCLUSION

Our study provides comprehensive data for patient-level improvements in pain and key ADLs. These data can be used to inform patients pre-operatively of expected outcomes, based on pre-operative status, which may further help patients set realistic goals for improvements after TKA.

Operative diagnosis for revision total hip arthroplasty is associated with patient-reported outcomes (PROs)

BACKGROUND

Little is known about the impact of the reason for revision total hip arthroplasty (THA) on the outcomes following revision THA. In this study, our objective was to assess the association of operative diagnosis with patient-reported outcomes (PROs) after revision THA.

METHODS

We used prospectively collected data from the Mayo Clinic Total Joint Registry that collects pre- and post-operative pain and function outcomes using a validated Hip questionnaire, on all revision THAs from 1993-2005. We used logistic regression to assess the odds of moderate-severe index hip pain and moderate-severe limitation in activities of daily living (ADLs) 2- and 5-years after revision THA. We calculated odds ratios (OR) and 95% confidence intervals (CIs).

RESULTS

For the 2- and 5-year cohorts, the operative diagnosis was loosening/wear/osteolysis in 73% and 75%; dislocation/bone or prosthesis fracture/instability or non-union in 17% and 15%; and failed prior arthroplasty with components removed/infection in 11% and 11%, respectively. In multivariable-adjusted analyses that included preoperative ADL limitations, compared to patients with loosening/wear/osteolysis, patients with dislocation/fracture/instability/non-union had OR of 2.2 (95% CI, 1.3-3.5; p = 0.002) for overall moderate-severe ADL limitation and those with failed prior arthroplasty/infection had OR of 1.6 (95% CI, 1.0-2.8; p = 0.06). At 5-years, ORs were lower and differences were no longer significant. Moderate-severe pain did not differ significantly by diagnosis, at 2- or 5-years in multivariable adjusted analyses, with one exception, i.e. failed prior arthroplasty/infection had a trend towards significance with odds ratio of 1.9 (95% CI, 0.9-3.8; p = 0.07).

CONCLUSIONS

Operative diagnosis is independently associated with ADL limitations, but not pain, at 2-years after revision THA. Patients should be informed of the risk of poorer short-term outcomes based on their diagnosis.

The importance of perceived helplessness and emotional health in understanding the relationship among pain, function, and satisfaction following revision knee replacement surgery

OBJECTIVE

Little is known about the relationships among pain, function, psychological variables like perceived helplessness and emotional health, and patient satisfaction in people with revision knee replacement surgery. We hypothesized that pain and function would have a direct association with satisfaction as well as an indirect association through patient perceptions of helplessness and emotional health.

DESIGN

This longitudinal study included 145 participants undergoing revision knee replacement surgery. Demographic data and expectation of benefit from surgery were recorded prior to surgery. The Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), the Arthritis Helplessness Scale (AHS) and the Mental Component Scale (MCS) of the SF-36 (emotional health) were collected prior to and 2 years post-surgery. Satisfaction was recorded 2 years post-surgery. Regression analyses were conducted to test for mediation effects of helplessness and MCS.

RESULTS

Participants were on average 69 years old and 54% were women. Participants were satisfied with the results of the surgery (mean ± standard deviation (SD) = 70.42 ± 31.46). Less pain and functional disability were associated with increased patient satisfaction and, the effect of pain or function was also mediated through helplessness whereby more pain and disability were associated with perceptions of helplessness and helplessness was associated with lower satisfaction. MCS did not mediate the relationship of pain and function with satisfaction.

CONCLUSION

Helplessness plays an important role in understanding patient satisfaction. Interventions aimed at improving patient outcome should target not only pain and function but also should address strategies to support people in managing following knee revision surgery to maximize satisfaction with outcome.

Income and patient-reported outcomes (PROs) after primary total knee arthroplasty

BACKGROUND

To assess whether income is associated with patient-reported outcomes (PROs) after primary total knee arthroplasty (TKA).

METHODS

We used prospectively collected data from the Mayo Clinic Total Joint Registry to assess the association of income with index knee functional improvement, moderate to severe pain and moderate to severe activity limitation at 2-year and 5-year follow-up after primary TKA using multivariable-adjusted logistic regression analyses.

RESULTS

There were 7, 139 primary TKAs at 2 years and 4, 234 at 5 years. In multivariable-adjusted analyses, at 2-year follow-up, compared to income > US$45, 000, lower incomes of ≤ US$35, 000 and > US$35, 000 to 45, 000 were associated (1) significantly with moderate to severe pain with an odds ratio (OR) 0.61 (95% CI 0.40 to 0.94) (P = 0.02) and 0.68 (95% CI 0.49 to 0.94) (P = 0.02); and (2) trended towards significance for moderate to severe activity limitation with OR 0.78 (95% CI 0.60 to 1.02) (P = 0.07) and no significant association with OR 0.96 (95% CI 0.78 to 1.20) (P = 0.75), respectively. At 5 years, odds were not statistically significantly different by income, although numerically they favored lower income. In multivariable-adjusted analyses, overall improvement in knee function was rated as 'better' slightly more often at 2 years by patients with income in the ≤ US$35, 000 range compared to patients with income > US$45, 000, with an OR 1.9 (95% CI 1.0 to 3.6) (P = 0.06).

CONCLUSIONS

We found that patients with lower income had better pain outcomes compared to patients with higher income. There was more improvement in knee function, and a trend towards less overall activity limitation after primary TKA in lower income patients compared to those with higher incomes. Insights into mediators of these relationships need to be investigated to understand how income influences outcomes after TKA.

Factors predicting weight-bearing asymmetry 1month after unilateral total knee arthroplasty: a cross-sectional study

Factors predicting weight-bearing asymmetry (WBA) after unilateral total knee arthroplasty (TKA) are not known. However, identifying modifiable and non-modifiable predictors of WBA is needed to optimize rehabilitation, especially since WBA is negatively correlated to poor functional performance. The purpose of this study was to identify factors predictive of WBA during sit-stand transitions for people 1month following unilateral TKA.

METHODS

Fifty-nine people were tested preoperatively and 1month following unilateral TKA for WBA using average vertical ground reaction force under each foot during the Five Times Sit-to-Stand Test. Candidate variables tested in the regression analysis represented physical impairments (strength, muscle activation, pain, and motion), demographics, anthropometrics, and movement compensations.

RESULTS

WBA, measured as the ratio of surgical/non-surgical limb vertical ground reaction force, was 0.69 (0.18) (mean (SD)) 1month after TKA. Regression analysis identified preoperative WBA (β=0.40), quadriceps strength ratio (β=0.31), and hamstrings strength ratio (β=0.19) as factors predictive of WBA 1month after TKA (R(2)=0.30).

CONCLUSION

Greater amounts of WBA 1month after TKA are predicted by modifiable factors including habitual movement pattern and asymmetry in quadriceps and hamstrings strength.

The aetiology of total knee arthroplasty failure influences the improvement in knee function

BACKGROUND

Some indications for revision total knee arthroplasty (TKA), e.g. arthrofibrosis, have been identified to yield inferior results. The aim of this study was to analyse the results of revision TKA according to aetiology of TKA failure.

PATIENTS AND METHODS

The results of 97 consecutive revision TKA in 97 patients stratified according to the aetiology of primary TKA failure (periprosthetic infection, aseptic loosening, instability and arthrofibrosis), were compared using the Knee Society Score (KSS). The effect of patient age, gender, BMI, American Society of Anesthesiologists (ASA) classification, interval to revision and the occurrence of complications on the outcome were also analysed.

RESULTS

After a mean follow-up of 29 months, the KSS had significantly improved in all patient groups (p < 0.001). The analysis of variance among patient groups depicted no significant differences between preoperative KSS (p = 0.618) and postoperative KSS (p = 0.915), while the magnitude of pre- to postoperative improvement showed significant differences between the groups (p = 0.006). The aetiology of primary TKA failure had an independent influence on pre- to postoperative improvement (p = 0.014). Of the other factors analysed, only the ASA classification had an independent impact on postoperative KSS (p = 0.045).

CONCLUSION

The aetiology of TKA failure has an effect on the improvement in knee function from revision TKA. As no difference was observed between patient groups postoperatively, similar clinical results can be expected independent of the aetiology of primary TKA failure.

Medical and psychological comorbidity predicts poor pain outcomes after total knee arthroplasty

OBJECTIVE

To study comorbidity correlates of moderate to severe pain after total knee arthroplasty (TKA).

METHODS

We analysed prospectively collected Total Joint Registry data to examine whether medical (heart disease, peripheral vascular disease, renal disease, chronic obstructive pulmonary disease, diabetes and CTD) and psychological (anxiety and depression) comorbidity is associated with moderate to severe pain after primary or revision TKA. Multivariable-adjusted logistic regression simultaneously adjusted for all comorbidities, age, sex, BMI, underlying diagnosis, American Society of Anesthesiologist (ASA) class, distance from medical centre and implant fixation (only for primary TKA) was used to analyse primary and revision TKA separately.

RESULTS

The primary TKA cohort consisted of 7139 and 4234 TKAs (response rates 65% and 57%) and the revision TKA cohort consisted of 1533 and 881 TKAs at 2 and 5 years (response rates 57% and 48%), respectively. In the primary TKA cohort, anxiety was associated with 1.4 higher odds (95% CI 1.0, 2.0) of moderate to severe index knee pain at 2 years; at 5 years, heart disease (OR 1.7; 95% CI 1.1, 2.6), depression (OR 1.7; 95% CI 1.1, 2.5) and anxiety (OR 1.9; 95% CI 1.2, 3.1) were significantly associated with moderate to severe pain. For revision TKA, CTD (OR 0.5; 95% CI 0.2, 0.9) and depression (OR 1.8; 95% CI 1.1, 3.1) were significantly associated with moderate to severe pain.

CONCLUSION

This study identified medical and psychological comorbidity risk factors for moderate to severe pain after primary and revision TKA. This information can be used to provide realistic outcome expectations for patients before undergoing primary or revision TKA.

Predictors of use of pain medications for persistent knee pain after primary Total Knee Arthroplasty: a cohort study using an institutional joint registry

INTRODUCTION

To study the use of pain medications for persistent index knee pain and their predictors after primary Total Knee Arthroplasty (TKA).

METHODS

The Mayo Total Joint Registry collects patient-reported data including pain medication use on all patients who undergo TKA. We used data from patients who underwent primary TKA from 1993-2005. We examined whether gender, age (reference, ≤ 60 yrs), body mass index (BMI; reference, <25 kg/m2), comorbidities measured by Deyo-Charlson index (5-point increase), anxiety and depression predicted use of pain medications (non-steroidal anti-inflammatory drugs (NSAIDs) and opioids) 2- and 5-years after primary TKA. Multivariable logistic regression additionally adjusted for operative diagnosis, American Society of Anesthesiologists (ASA) score, implant fixation and distance from the medical center.

RESULTS

7,139 of the 10,957 eligible (65%) at 2-years and 4,234 of 7,404 eligible (57%) completed questionnaires. Significant predictors of NSAIDs use were (Odds ratio (95% confidence interval)): male gender at 2- and 5-years, 0.5 (0.4, 0.6) and 0.6 (0.5, 0.8); age >70-80 years, 0.7 (0.5, 0.9), 0.6 (0.4, 0.8); and depression, 1.4 (1.0, 1.8) and 1.7 (1.1, 2.5). BMI ≥ 40 was associated with NSAIDs use only at 2-years, 1.6 (1.1, 2.5). Significant predictors of opioid pain medication use at 2- and 5-years were: male gender, 0.5 (0.3, 0.9) and 0.4 (0.2, 0.8); age >70-80 years, 0.3 (0.1, 0.6), 0.3 (0.1, 0.8); and anxiety, 3.0 (1.6, 5.7) and 4.0 (1.7, 9.4).

CONCLUSIONS

Female gender and younger age were associated with higher risk of use of NSAIDs and opioids after primary TKA. Depression was associated with higher NSAID use and anxiety with higher opioid pain medication use after primary TKA.

[Comorbidity from the patient perspective - does it work? Validity of a questionnaire on self-estimation of comorbidity (SCQ-D)]

To minimize the medical effort for the measurement of comorbidity, which is a relevant factor for various outcome measures, the Self-Administered Comorbidity Questionnaire (SCQ) for patient self-evaluation has been developed. After successfully testing the psychometric characteristics and content of the original English version a validation of the German translation (SCQ-D) has so far been lacking. A total of 218 patients with gonarthrosis and coxarthrosis (average age 71.5 years) were included in the survey. A questionnaire for doctors as well as patients was used to collect data at five different measurement times (postoperative, beginning and end of rehabilitation as well as 4 months and 1 year postoperatively). To evaluate the matching of comorbidities according to the SCQ-D and the Charlson Comorbidity Index (CCI), aggregate indices for "problems" and "treatment" as well as correlation and kappa coefficients were calculated. The assessment of predictive validity in terms of treatment outcome was operationalized using the WOMAC and the postoperative 1 year hospitalization by applying multilevel models. The patient self-assessment using the SCQ-D correlated well with the physician assessment using CCI in terms of aggregate indices of 13 given disease groups with r = 0.49 (problems) and r = 0.48 (treatment). However, the results showed significant differences for certain diseases in the conclusions. The comorbidity measured by the SCQ-D proved to be a valid predictor of the hospitalization and the treatment outcome. Concerning the need for resource efficient data collection especially in large sample studies, the SCQ-D is a useful patient self-administered instrument to assess the type and extent of comorbidities.

When do patient-reported assessments peak after revision knee arthroplasty?

BACKGROUND

The best timing for patient visits after revision TKA is unclear. Predictors of pain and function reported in the literature typically look at the influence at a given time that might not be ideal if the score is not at a peak or the earliest possible time. Moreover, most reports of predictors include revisions for infection, which typically have a poorer outcome, or for other indications with variable outcome.

QUESTIONS/PURPOSES

We therefore determined (1) the trend of recovery after revision TKA to determine the best time to measure the peak patient-reported pain and function scores and (2) the influence of comorbidities and age on the patterns of recovery.

METHODS

We prospectively followed 120 patients who had revision TKAs from 2003 to 2008. The patients were assessed within 6 weeks before surgery and at 12 weeks, 1 year, and annually thereafter. We obtained WOMAC and SF-36 scores at each visit. We used a linear mixed model analysis to assess predictors. The minimum followup was 2 years (mean, 3 years; range, 2-7 years).

RESULTS

The majority of improvements in the WOMAC and SF-36 scores occurred during the first year after surgery after which the scores stabilized. One of the seven independent preoperative variables studied (comorbidities) predicted a trend toward improvement of WOMAC pain, WOMAC function, and SF-36 bodily pain scores. The greater the numbers of comorbidities, the worse were the scores. Age, gender, BMI, indication for surgery, and surgeon did not independently influence the WOMAC or SF-36.

CONCLUSION

Our data suggest that one of the times for patient visits after revision TKA should be 1 year after surgery. This time allows for key discrimination of implant performance. The data also confirm that patients with a greater number of comorbidities had less functional benefit from revision surgery.

LEVEL OF EVIDENCE

Level II, prognostic study. See the Guidelines for Authors for a complete description of levels of evidence.

Higher body mass index is not associated with worse pain outcomes after primary or revision total knee arthroplasty

We assessed whether higher body mass index (BMI) is associated with higher risk of moderate-severe knee pain 2 and 5 years after primary or revision total knee arthroplasty (TKA).We adjusted for sex, age, comorbidity, operative diagnosis, and implant fixation in multivariable logistic regression. Body mass index (reference, b 25 kg/m2) was not associated with moderate severe knee pain at 2 years post primary TKA (odds ratio [95% confidence interval], 25-29.9, 1.02[0.75-1.39], P = .90; 30-34.9, 0.93 [0.65-1.34], P = .71; 35-39.9, 1.16 [0.77-1.74], P = .47; ≥ 40,1.09 [0.69-1.73], [all P values ≥ .47]). Similarly, BMI was not associated with moderate-severe pain at 5-year primary TKA and at 2-year and 5-year revision TKA follow-up. Lack of association of higher BMI with poor pain outcomes post-TKA implies that TKA should not be denied to obese patients for fear of suboptimal outcomes.

Patterns of improvement following oncologic reconstructrion compared to total knee arthroplasty and revision knee arthroplasty

Limb salvage surgery for primary malignant bone tumors of the lower limbs requires complete resection of the tumor, followed by a reconstruction to restore function. In contrast to the abundant information on total knee arthroplasty, data on the recovery pattern of limb salvage surgery is largely limited. With the aim of guiding patient expectations and optimizing care, we retrospectively compared the clinical outcomes among patients following oncologic knee reconstruction, primary total knee arthroplasty, and revision total knee arthroplasty. From January, 2001 to June, 2009, we identified a cohort of 503 primary total knee arthroplasties, 55 revision knee arthroplasties, and 15 oncologic reconstructions. Outcomes were assessed by the validated Short Form-36 (SF-36) health questionnaire. We found that oncologic patients significantly improved their Physical Component Score at one and minimum two-year follow up compared to baseline (p< 0.05) with the majority of improvement (90%) made within the first year following surgery. This is a similar pattern to that observed following primary and revision total knee arthroplasty.