Comparable outcomes after total knee arthroplasty in patients under 55 years than in older patients: a matched prospective study with minimum follow-up of 10 years

Is Younger Age a Risk Factor for Failure Following Aseptic Revision Total Knee Arthroplasty?

BACKGROUND

Revision total knee arthroplasties (rTKAs) are being performed more frequently in the United States in younger patients. Few large studies have evaluated the effect of age following rTKA. The study sought to evaluate the effect of age on rTKA outcomes.

METHODS

The American Joint Replacement Registry was used to identify aseptic rTKAs in younger (18 to 64 years, n = 32,631) and older (> 65 years, n = 43,992) patients from January 2012 to September 2020, allowing for a minimum 2-year follow-up. The mean age was 56 years in the younger cohort and 73 years in the older cohort. The mean follow-up was 5.4 years. Sex and body mass index were similar between groups. Kaplan-Meier survivorship analysis was performed with rerevision as the primary endpoint. Secondarily, multivariate analyses were performed to adjust for demographics and comorbidities.

RESULTS

The proportion with rerevision was higher in the younger cohort compared to the older (8.1 versus 5.4%, P < 0.001). The 10-year survivorship free of all-cause rerevision was 90.2% (95% confidence interval [CI]: 89.7 to 90.7) in the younger cohort versus 93.7% (95% CI: 93.4 to 94.1) in the older cohort (P < 0.0001). Younger age was significantly associated with a higher adjusted hazard ratio (HR) for all-cause rerevision (HR: 1.4, 95% CI: 1.3 to 1.6), as were men (HR: 1.4, 95% CI: 1.2 to 1.5) and initial revision for instability (HR: 1.3, 95% CI: 1.1 to 1.5). In a subgroup analysis of patients aged < 65 years, a 5-year decrease in age was associated with a 10.0% increase in risk of rerevision. Indications for rerevisions differed among the younger and older cohorts (P < 0.01): infection (30.2 versus 34.9%), aseptic loosening (19.0 versus 15.8%), and instability (12.2 versus 12.7%).

CONCLUSIONS

Younger age, men, and initial revision performed for instability were associated with significantly increased risk for all-cause rerevision following aseptic rTKA. Notably, age may have a continuous effect on rerevision rates, as each 5-year decrease in age was associated with a 10% increase in risk of rerevision. Future research may further elucidate these increased risks in this younger patient population.

Impacts of Knee Arthroplasty on Activity Level and Knee Function in Young Patients: A Systematic Review

The annual demand for knee arthroplasty has been steadily rising, particularly in younger patients. The primary objective of this systematic review was to determine the impact of knee arthroplasties on knee function and activity levels in young (≤55 years) patients. A PubMed search from inception (1977) to March 2022 to identify eligible studies produced 640 peer-reviewed studies for consideration. A total of 18 studies including 4,186 knee arthroplasties in 3,200 patients (mean patient age at the time of surgery: 47.4 years, range: 18-55 years) were ultimately included for analysis. Mean final follow-up (FFU) duration was 5.8 years (range: 2-25.1 years). Mean FFU improvement in Knee Society Clinical Score was 48.0 (1,625 knees, range: 20.9-69.0), Knee Society Function Score was 37.4 (1,284 knees, range: 20-65). Mean FFU for the Tegner and Lysholm activity scale was 2.8 (4 studies, 548 knees, range: 0.7-4.2); University of California Los Angeles Physical Activity Questionnaire score was 2.8 (3 studies, 387 knees, range: 1.2-5); lower extremity activity scale was 1.84 (529 knees). The available evidence suggest that young patients typically realize sustained improvements in knee function compared to preoperative levels; however, these improvements do not typically translate into a return to desired activity levels or quality of life, and this patient population should expect a higher and earlier risk for revision than their older counterparts. Further research, including robust registry data, is needed to establish evidence-based indications, expectations, and prognoses for outcomes after knee arthroplasty in young and active patients.

[Total knee replacement in different age groups]

OBJECTIVE

To evaluate the efficacy and quality of life in long-term period (1 year) after total knee replacement in various age groups.

MATERIAL AND METHODS

We studied 134 patients after unilateral primary total knee replacement. The KOOS and SF-36 questionnaires were used to assess the therapeutic effect (functionality and symptoms) and quality of life in patients with knee osteoarthritis.

RESULTS

At baseline, group I (young patients) had low KOOS pain scores (39.42±16.42), function scores (50.18±19.16) and QoL scores (18.2±15.9) compared to other age groups. A year after surgery, group I (<55 years) had significantly lower KOOS scores of pain, function and quality of life compared to group III (>65 years). Multiple regression analysis showed that age was a significant predictor of pain, but not a function after a year.

CONCLUSION

Total knee replacement gives a noticeable improvement in pain, functionality and quality of life in all age groups. However, there are significant age-related differences in preoperative assessment of pain, quality of life and mental health, as well as in final indicators of postoperative pain and quality of life. Indeed, young patients (<50 years) report more intense pain and worse quality of life. These data may be used in clinical practice to improve decision-making and patient expectations before total knee replacement.

Age-Related Differences in Pain, Function, and Quality of Life Following Primary Total Knee Arthroplasty: Results from a FORCE-TJR Cohort

INTRODUCTION

The impact of age on patient outcomes after total knee arthroplasty (TKA) remains controversial. Age has shown no effect on outcome in some studies, while others have reported better or worse outcome in younger patients. The aims of this study were to determine the differences in pain, function, and quality of life reported one-year after TKA across different age groups.

METHODS

A prospective, multi-center cohort of 11,602 unilateral primary TKA patients was evaluated. Demographic data, comorbid conditions, and patient-reported outcome measures (PROMs) including the knee injury and osteoarthritis outcome score (KOOS), KOOS-12, KOOS JR, and Short-Form health survey (12-item) were collected pre- and at one-year postoperatively. Descriptive statistics were generated, stratified by age [< 55 years (younger adult), 55 to 64 years (older adult), 65 to 74 years (early elder), and ≥ 75 years (late elder)], and differences in pain, function, and quality of life among the four age groups were evaluated using Chi-square and Kruskal-Wallis tests. Multivariate regression models with 95% confidence interval (CI) were performed to determine if age was predictive for KOOS pain and function scores.

RESULTS

Prior to surgery, younger patients (< 55 years) reported worse KOOS pain (39), function (50), and quality of life (18) scores with poor mental health score (47) than other older patient groups. The mean pre-op score differences across the age groups in the KOOS total score (9.37), KOOS pain (11.61), KOOS-12 pain (10.14), and KOOS/KOOS-12 QoL (12.60) reached the calculated minimal clinically important difference (MCID). At one-year after TKA, younger patients (< 55 years) reported lower KOOS pain, function, and quality of life scores when compared to older patients (≥ 75 years). The differences in one-year postop scores among the 4 age groups (ranging from 4.0 to 12.2) reached the MCID for pain (10.4) and quality of life (12.2). Younger patients (< 55 years) achieved higher baseline to one-year pain (36.8 points), function (30.3 points), and quality of life (40.7 points) score changes when compared to older patients ≥ 75 years. Although statistically significant, the differences in score changes among the age groups were clinically irrelevant. The multivariate regression analyses showed that age was a significant predictor for pain, but not for function at one year where KOOS pain score was predicted to be higher (less pain) (β =6.17; 95% CI (4.12- 8.22) (P<0.001) in older patients (≥ 75 years) when compared to younger patients (< 55 years).

CONCLUSION

A TKA provides a dramatic improvement in pain, function, and quality of life in all age groups. However, there are age-related clinically significant differences in pre-operative pain, quality of life, and mental health and in final post-operative pain and quality of life scores with younger patients (< 55 years) reporting more pain, less quality of life, and worse pre-operative mental health. The PROM data presented here can be used clinically to improve shared decision making and patient expectations prior to TKA.

Patient-Reported Outcomes following Total Knee Replacement in Patients Aged 65 Years and Over-A Systematic Review

A previous systematic review showed positive patient-reported outcomes following total knee replacement (TKR) in patients aged < 65 years. However, the question remains as to whether these results are replicated for older individuals. This systematic review evaluated the patient-reported outcomes following TKR in individuals aged ≥ 65 years. A systematic search of Ovid MEDLINE, EMBASE, and Cochrane library were performed to identify studies examining disease-specific or health-related quality of life outcomes following TKR. Qualitative evidence synthesis was performed. Eighteen studies with low (n = 1), moderate (n = 6), or serious (n = 11) overall risk of bias were included, with evidence syntheses derived from 20,826 patients. Four studies reported on pain scales, showing improvement of pain from 6 months to 10 years postoperatively. Nine studies examined functional outcomes, showing significant improvements from 6 months to 10 years after TKR. Improvement in health-related quality of life was evident in six studies over 6 months to 2 years. All four studies examining satisfaction reported overall satisfaction with TKR results. TKR results in reduced pain, improved function, and increased quality of life for individuals aged ≥ 65 years. The improvement in patient-reported outcomes needs to be utilised in conjunction with physician expertise to determine what would comprise clinically significant differences.

Survivorship of 500 Cementless Total Knee Arthroplasties in Patients Under 55 Years of Age

BACKGROUND

With respect to survivorship following total knee arthroplasty (TKA), joint registries consistently demonstrate higher revision rates for both genders in those aged less than 55 years. The present study analyzed the survivorship of 500 cementless TKAs performed in this age group in a high-volume primary joint unit where cementless TKA has traditionally been used for the majority of patients.

METHODS

This was a retrospective review of 500 consecutive TKAs performed in patients aged less than 55 years between March 1994 and April 2017. The primary outcome measures for the study were survivorship and all-cause revisions. Secondary outcome measures included nonrevision procedures, clinical, functional, and radiological outcomes.

RESULTS

An all-cause survival rate of 98.4% and an aseptic survival rate of 99.2% at a median time of 10.7 years (interquartile range 7.3-14.9, range 0.2-27.7) were found. Four patents were revised for infection, 2 for stiffness, 1 for aseptic loosening of the tibial component, and 1 for a patella that was resurfaced for anterior knee pain. Thirty four patients (6.8%) had a nonrevision procedure with manipulation under anesthetic accounting for 27. On a multivariate analysis, preoperative range of motion and female gender were negatively associated with postoperative range of motion (P < .001 and P = .003, respectively). Sixty seven patients (17.3%) had radioluscent lines and on a multivariate analysis, there were no significant predictors of radiolucent lines.

CONCLUSION

Cementless TKA in the young patient can achieve excellent clinical and functional outcomes. At a median of 10.7 years, aseptic revision rates are exceptionally low at 0.8% for the entire cohort.

Factors contributing to 1-year dissatisfaction after total knee arthroplasty: a nomogram prediction model

Background

Identifying risk factors and early intervention are critical for improving the satisfaction rate of total knee arthroplasty (TKA). Our study aimed to identify patient-specific variables and establish a nomogram model to predict dissatisfaction at 1 year after TKA.

Methods

This prospective cohort study involved 208 consecutive primary TKA patients with end-stage arthritis who completed self-reported measures preoperatively and at 1 year postoperatively. All participants were randomized into a training cohort (n = 154) and validation cohort (n = 54). Multiple regression models with preoperative and postoperative factors were used to establish the nomogram model for dissatisfaction at 1 year postoperatively. The least absolute shrinkage and selection operator method was used to screen the suitable and effective risk factors (demographic variables, preoperative variables, surgical variable, and postoperative variables) collected. These variables were compared between the satisfied and dissatisfied groups in the training cohort. The receiver operating characteristic (ROC) curve, calibration plot, and decision curve analysis were used to validate the discrimination, calibration, and clinical usefulness of the model. Results were evaluated by internal validation of the validation cohort.

Results

The overall satisfaction rate 1 year after TKA was 77.8%. The nomogram prediction model included the following risk factors: gender; primary diagnosis; postoperative residual pain; poor postoperative range of motion; wound healing; and the rate of change in the degree of coronal lower limb alignment (hip–knee–ankle angle, HKA).The ROC curves of the training and validation cohorts were 0.9206 (95% confidence interval [CI], 0.8785–0.9627) and 0.9662 (0.9231, 1.0000) (95% CI, 0.9231, 1.0000), respectively. The Hosmer–Lemeshow test showed good calibration of the nomogram (training cohort, p = 0.218; validation cohort, p = 0.103).

Conclusion

This study developed a prediction nomogram model based on partially modifiable risk factors for predicting dissatisfaction 1 year after TKA. This model demonstrated good discriminative capacity for identifying those at greatest risk for dissatisfaction and may help surgeons and patients identify and evaluate the risk factors for dissatisfaction and optimize TKA outcomes.

What Are the All-Cause Survivorship Rates and Functional Outcomes in Patients Younger Than 55 Years Undergoing Primary Knee Arthroplasty? A Systematic Review

BACKGROUND

Approximately one-fourth of TKAs will be performed in patients 55 years or younger within the next decade. Postoperative outcomes for younger patients who had a knee arthroplasty were systematically reviewed in 2011; however, numerous studies evaluating young patients who had both a TKA and unicompartmental knee arthroplasty (UKA) have been reported in the past decade. Therefore, to better counsel this growing population of young patients undergoing knee arthroplasty, an updated understanding of their expected postoperative outcomes is warranted.

QUESTIONS/PURPOSES

In this systematic review, we evaluated (1) all-cause survivorship, (2) reasons for revision, (3) patient-reported outcomes, and (4) return to physical activity and sport in patients 55 years or younger undergoing primary TKA or UKA.

METHODS

A comprehensive search of PubMed, Medline, SportDiscus, and CINAHL was performed to identify all original studies evaluating outcomes after primary knee arthroplasty for young patients (55 years of age or younger) from inception until March 2021. The following keywords were used: knee, arthroplasty, replacement, pain, function, revision, survivorship, sport, physical activity, and return to play. Only original research studies that were related to knee arthroplasty and reported postoperative outcomes with a minimum 1-year follow-up for patients 55 years or younger were included. Unpublished materials, publications not available in English, and studies with a primary diagnosis of rheumatoid arthritis were excluded. The Methodological Index for Non-Randomized Studies (MINORS) score was used to evaluate the study quality of case series and comparative studies, while the Cochrane Risk of Bias tool and the Jadad scale were used for randomized studies. The primary outcomes of interest for this study were all-cause survivorship rate, reasons for all-cause revision, Knee Society and Knee Society Function scores (minimum clinically important difference [MCID] 7.2 and 9.7, respectively), WOMAC scores (MCID 10), Tegner scores (no reported MCID for knee arthroplasty), and return to physical activity or sport. Knee Society and Knee Society Function scores range from 0 to 100, with scores from 85 to 100 considered excellent and below 60 representing poor outcomes. All-cause survivorship rate and reasons for revision were both reported in 17 total studies. Knee Society scores were presented in 19 and Knee Society Function scores were reported in 18 included studies. WOMAC scores and Tegner scores were each found in four included studies, and return to physical activity and return to sport analyses were performed in seven studies. Overall, 21 TKA studies and five UKA studies were included in this analysis, featuring 3095 TKA knees and 482 UKA knees.

RESULTS

Kaplan-Meier estimates of all-cause survivorship ranged from 90% to 98% at 5 to 10 years of follow-up after TKA and from 84% to 99% (95% CI 93% to 98%) at 10 years to 20 years post-TKA. All-cause UKA survivorship was 90% at 10 years and 75% at 19 years in the largest Kaplan-Meier estimate of survivorship for patients younger than 55 who underwent UKA. Common reasons for revision in TKA patients were polyethylene wear/loosening, aseptic tibial loosening, and infection, and in UKA patients the common reasons for revision were knee pain, aseptic loosening, progression of knee osteoarthritis, and polyethylene wear/loosening. Knee Society scores ranged from 85 to 98 for 5-year to 10-year follow-up and ranged from 86 to 97 at 10-year to 20-year follow-up in TKA patients. Knee Society Function scores ranged from 70 to 95 for 5-year to 10-year follow-up and ranged from 79 to 86 at 10-year to 20-year follow-up. Return to physical activity and sport was reported variably; however, most patients younger than 55 have improved physical activity levels after knee arthroplasty relative to preoperative levels.

CONCLUSION

Although all-cause survivorship rates were frequently above 90% and patient-reported outcome scores were generally in the good to excellent range, several studies reported long-term survivorship rates from 70% to 85% and fair patient-reported outcome scores, which must be factored into any preoperative counseling with patients. We could not control for surgeon volume in this report, and prior research suggests that increasing volume is associated with less frequent complications; in addition, the studies we included were variably affected by selection bias, transfer bias, and assessment bias, which makes it likely that the findings of our review represent best-case estimates. To limit the frequency of revision in patients younger than 55 years undergoing TKA, clinicians should be cautious of polyethylene wear/loosening, aseptic tibial loosening, and infection, while knee pain and progression of knee osteoarthritis are also common reasons for revision in patients younger than 55 undergoing UKA. Further research should isolate younger knee arthroplasty patients and evaluate postoperative activity levels while accounting for preoperative physical activity and sport participation.

LEVEL OF EVIDENCE

Level IV, therapeutic study.

A new prediction model for patient satisfaction after total knee arthroplasty and the roles of different scoring systems: a retrospective cohort study

BACKGROUND

Although total knee arthroplasty (TKA) is an efficacious treatment for end-stage osteoarthritis, ~20% of patients are dissatisfied with the results. We determined which factors contribute to patient satisfaction and compared the various scoring systems before and after surgery.

METHODS

In this retrospective cohort study, 545 patients were enrolled and evaluated preoperatively and 1 year postoperatively. Patient demographics, as well as scores for the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), Short Form (SF)-12, and 1989 Knee Society Clinical Rating System (1989 KSS), were recorded preoperatively and postoperatively. The possible predictors were introduced into a prediction model. Scores for overall satisfaction and the 2011 Knee Society Score (2011 KSS) were also assessed after TKA to identify the accuracy and agreement of the systems.

RESULTS

There were 134 male patients and 411 female patients, with an overall prevalence of satisfaction of 83.7% 1 year after surgery. A history of surgery (p < 0.001) and the 1989 KSS and SF-12 were of the utmost importance in the prediction model, whereas the WOMAC score had a vital role postoperatively (change in WOMAC pain score, p < 0.001; change in WOMAC physical function score, p < 0.001; postoperative WOMAC pain score, p = 0.004). C-index of model was 0.898 > 0.70 (95% confidence interval (CI): 0.86-0.94). The Hosmer-Lemeshow test showed a p value of 0.586, and the AUC of external cohort was 0.953 (sensitivity=0.87, specificity=0.97). The agreement between the assessment of overall satisfaction and the 2011 KSS satisfaction assessment was general (Kappa=0.437 > 0.4, p < 0.001).

CONCLUSION

A history of surgery, the preoperative 1989 KSS, and the preoperative SF-12 influenced patient satisfaction after primary TKA. We recommend the WOMAC (particularly the pain subscale score) to reflect overall patient satisfaction postoperatively.

Long-Term (Up to 27 Years) Prospective, Randomized Study of Mobile-Bearing and Fixed-Bearing Total Knee Arthroplasties in Patients <60 Years of Age With Osteoarthritis

BACKGROUND

Our study determined long-term (up to 27 years) results of fixed-bearing vs mobile-bearing total knee arthroplasties (TKAs) in patients <60 years with osteoarthritis.

METHODS

This study included 291 patients (582 knees; mean age 58 ± 5 years), who received a mobile-bearing TKA in one knee and a fixed-bearing TKA in the other. The mean duration of follow-up was 26.3 y (range 24-27).

RESULTS

At the latest follow-up, the mean Knee Society knee scores (91 ± 9 vs 89 ± 11 points, P = .383), Western Ontario and McMaster Universities Osteoarthritis Index (35 ± 7 vs 37 ± 6 points, P = .165), range of knee motion (128° ± 13° vs 125° ± 15°, P = .898), and University of California, Los Angeles activity score (6 ± 4 vs 6 ± 4 points, P = 1.000) were below the level of clinical significance between the 2 groups. Revision of mobile-bearing and fixed-bearing TKA occurred in 16 (5.5%) and 20 knees (6.9%), respectively. The rate of survival at 27 years for mobile-bearing and fixed-bearing TKA was 94.5% (95% confidence interval 89-100) and 93.1% (95% confidence interval 88-98), respectively, and no significant differences were observed between the groups. Osteolysis was identified in 4 knees (1.4%) in each group.

CONCLUSION

There were no significant differences in functional outcomes, rate of loosening, osteolysis, or survivorship between the 2 groups.

The projected volume of primary and revision total knee arthroplasty will place an immense burden on future health care systems over the next 30 years

PURPOSE

Total knee arthroplasty (TKA) rates have increased substantially in the recent decades worldwide, with Germany being one of the leading countries in the prevalence of TKA. The aim of this study was to provide an overview of treatment changes during the last decade and to project the expected burden of primary and revision TKA (rTKA) for the next 30 years.

METHODS

Comprehensive nationwide data from Germany was used to quantify primary and revision TKA rates as a function of age and gender. Projections were performed with use of a Poisson regression models and a combination of exponential smoothing and autoregressive integrated moving average models on historical procedure rates in relation to official population projections from 2020 to 2050.

RESULTS

The incidence rate of primary TKAs is projected to increase by around 43% to 299 per 100,000 inhabitants [95% CI 231-368], leading to a projected total number of 225,957 primary TKAs in 2050 (95% CI 178,804-276,442). This increase has been related to a growing number of TKA performed in male patients, with the highest increase modelled in patients between 50 and 65 years of age. At the same time, the annual total number of revision procedures is forecast to increase even more rapidly by almost 90%, accounting for 47,313 (95% CI 15,741-78,885; IR = 62.7 per 100,000, 95% CI 20.8-104.5) procedures by 2050. Those numbers are primarily associated with a rising number of rTKAs secondary to periprosthetic joint infection (PJI).

CONCLUSIONS

Using this country- specific forecast approach, a rising number of primary TKA and an even more rapidly growing number of rTKA, especially for PJI, has been projected until 2050, which will inevitably provide a huge challenge for the future health care system. As many other industrialized nations will face similar demographic and procedure-specific developments, these forecasts should be alarming for many health care systems worldwide and emphasize the tremendous need for an appropriate financial and human resource management in the future.

LEVEL OF EVIDENCE

Level III, prognostic study, economic and decision analysis.

Is there an optimal age for total knee arthroplasty?: A systematic review

PURPOSE

The purpose of this systematic review was to elucidate the optimal age for patients undergoing total knee arthroplasty (TKA), to optimize the balance between the benefits and risks by analyzing patient-reported outcome measurements (PROM), revision rate, and mortality according to age.

MATERIALS AND METHODS

A rigorous and systematic approach was used and each of the selected studies was evaluated for methodological quality. Data were extracted according to the following: study design, patients enrolled, patient age at the time of surgery, follow-up period, PROM, revision rate, and mortality.

RESULTS

Thirty-nine articles were included in the final analysis. The results were inconsistent in the PROM analysis, but there was consensus that PROM were good in patients in their 70s . In the revision rate analysis, there was consensus that the revision rate tends to increase in TKA in younger patients, but no significant difference was observed in patients > 70 years of age. In the mortality analysis, there was consensus that the mortality was not significantly different in patients < 80 years of age, but tended to increase with age.

CONCLUSION

This systematic review shows that the PROM were good when TKA was performed in patients between 70 and 80 years of age; the best PROM could be achieved around 70 years of age, and no significant difference in the revision or mortality rates was observed between 70 and 80 years of age; however, mortality tended to increase with age. Therefore, the early 70s could be recommended as an optimal age to undergo TKA.

Patient-Reported Outcomes Following Total Knee Replacement in Patients <65 Years of Age-A Systematic Review and Meta-Analysis

An increasing number of total knee replacements (TKRs) are being performed in response to the growing burden of osteoarthritis. Patients <65 years of age represent the fastest growing group of TKR recipients and are expected to account for an increasing number of primary and revision procedures. Concerns have been raised about the outcomes that can be expected by this age demographic who are more active, physically demanding, and have longer life expectancies compared to older TKR recipients. This systematic review and meta-analysis evaluated the effectiveness of TKR for osteoarthritis in patients <65 years of age, compared to older individuals. A systematic search of Embase and Medline was conducted to identify studies which examined patient-reported outcomes measured using disease-specific and generic health-related quality of life instruments. Ten studies met our inclusion criteria and were included in this review. These studies comprised 1747 TKRs performed between 1977 and 2014. In the meta-analysis of two prospective studies (288 TKRs), patients <65 years of age were able to attain large and clinically meaningful improvements in pain, function, and quality of life. One of these studies (61 TKRs) suggested that patients <55 years of age attained a larger degree of improvement compared to older individuals. Results into the second postoperative decade were less certain, with some data suggesting a high prevalence of pain and patterns of functional decline. Further research is required to investigate longer-term outcomes following TKR for osteoarthritis in younger patients.

The Cost-Effectiveness of Platelet-Rich Plasma Injections for Knee Osteoarthritis: A Markov Decision Analysis

BACKGROUND

Use of platelet-rich-plasma (PRP) injections for treating knee osteoarthritis has increased over the past decade. We used cost-effectiveness analysis to evaluate the value of PRP in delaying the need for total knee arthroplasty (TKA).

METHODS

We developed a Markov model to analyze the baseline case: a 55-year-old patient with Kellgren-Lawrence grade-II or III knee osteoarthritis undergoing a series of 3 PRP injections with a 1-year delay to TKA versus a TKA from the outset. Both health-care payer and societal perspectives were included. Transition probabilities were derived from systematic review of 72 studies, quality-of-life (QOL) values from the Tufts University Cost-Effectiveness Analysis Registry, and individual costs from Medicare reimbursement schedules. Primary outcome measures were total costs and quality-adjusted life years (QALYs), organized into incremental cost-effectiveness ratios (ICERs) and evaluated against willingness-to-pay thresholds of $50,000 and $100,000. One and 2-way sensitivity analyses were performed as well as a probabilistic analysis varying PRP-injection cost, TKA delay intervals, and TKA outcomes over 10,000 different simulations.

RESULTS

From a health-care payer perspective, PRP resulted in 14.55 QALYs compared with 14.63 for TKA from the outset, with total health-care costs of $26,619 and $26,235, respectively. TKA from the outset produced a higher number of QALYs at a lower cost, so it dominated. From a societal perspective, PRP cost $49,090 versus $49,424 for TKA from the outset. The ICER for TKA from the outset was $4,175 per QALY, below the $50,000 willingness-to-pay threshold. Assuming the $728 published cost of a PRP injection, no delay time that was <10 years produced a cost-effective course. When the QOL value was increased from the published value of 0.788 to >0.89, PRP therapy was cost-effective with even a 1-year delay to TKA.

CONCLUSIONS

When considering direct and unpaid indirect costs, PRP injections are not cost-effective. The primary factor preventing PRP from being cost-effective is not the price per injection but rather a lack of established clinical efficacy in relieving pain and improving function and in delaying TKA. PRP may have value for higher-risk patients with high perioperative complication rates, higher TKA revision rates, or poorer postoperative outcomes.

LEVEL OF EVIDENCE

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

Physical Therapist Management of Total Knee Arthroplasty

A clinical practice guideline on total knee arthroplasty was developed by an American Physical Therapy (APTA) volunteer guideline development group that consisted of physical therapists, an orthopedic surgeon, a nurse, and a consumer. The guideline was based on systematic reviews of current scientific and clinical information and accepted approaches to management of total knee arthroplasty.

Higher Rate of Early Revision Following Primary Total Knee Arthroplasty in Patients Under Age 55: A Cautionary Tale

BACKGROUND

There has been an increased number of total knee arthroplasties (TKAs) performed in young and active patients. Although improved materials have decreased the likelihood of early catastrophic wear, concerns remain with the performance and survivorship of TKA implants in this patient population. The purpose this study is to evaluate perioperative complications, patient-reported outcomes, and implant survivorship of TKAs performed in patients under age 55.

METHODS

We retrospectively reviewed 4259 primary TKAs performed over a 4-year period. There were 741 TKAs in patients under age 55. The primary outcome of interest was rate of revision at 30 days, 1, 2, and 5-year time points. Secondary outcomes included postoperative transfusion rate, length of stay, rate of deep vein thrombosis/pulmonary embolism, need for manipulation under anesthesia, readmission and reoperation within 30 days, as well as patient-reported outcomes.

RESULTS

There were 3518 patients over 55 years and 741 patients under 55 years. Overall, 175 patients required revision (4.1%). Patients under 55 years had significantly higher cumulative revision rate at 1 (3.4% vs 1.8%, P < .001), 2 (5.0% vs 2.4%, P < .001), and 5 years (7.3% vs 3.7%, P < .001). Patients under 55 years had a higher rate of early reoperation. Patients over 55 years required more transfusions and suffered a higher rate of early deep vein thrombosis. Patients over 55 years had significantly greater improvements in Patient Reported Outcome Measurement Information System Global 10 Physical scores at 6 months postoperatively compared to patients under 55 years.

CONCLUSIONS

Despite improvements in TKA implants, young and active patients remained at higher risk of early revision compared to older patients. The data should be used to counsel young prospective TKA patients about the early risk of reoperation and non-wear-related complications.

Prediction of the need for manipulation under anesthesia for flexion contracture after total knee arthroplasty in patients of advanced age

Objective

This study was performed to develop a prediction model for requiring manipulation under anesthesia (MUA) for flexion contracture after total knee arthroplasty (TKA) in patients of advanced age.

Methods

We retrospectively reviewed 269 patients of advanced age undergoing primary TKA in one center with a minimum 1-year follow-up. Patients who underwent postoperative MUA had flexion contracture of >10° after 4 weeks of postoperative rehabilitation, and their demographic data and preoperative clinical conditions [knee diagnosis, diabetes mellitus, hypertension, lumbar spinal disorders, hip disorders, ankle disorders, knee deformity (varus/valgus), preoperative flexion contracture (PFC), range of motion (ROM), and Hospital for Special Surgery (HSS) knee score] were compared with those of patients without MUA. All preoperative factors were collected to develop the predictive model.

Results

Thirty patients underwent MUA. Patients who underwent MUA after surgery had significant differences in PFC, higher HSS knee scores before surgery (59.10 ± 7.22 vs. 55.70 ± 13.09), and lower preoperative ROM (81.57 ± 30.86 vs. 95.47 ± 24.36) than those who did not undergo MUA.

Conclusion

A prediction model for MUA in advanced-age patients with flexion contracture was developed and mainly consisted of preoperative risk factors including PFC, HSS scores, and ROM.

Patient age of less than 55 years is not an independent predictor of functional improvement or satisfaction after total knee arthroplasty

INTRODUCTION

Management of the young patient with end-stage osteoarthritis of the knee is difficult, with surgical options of osteotomy, partial or total knee arthroplasty (TKA). The primary aim of this study was to assess whether age of less than 55 years was an independent predictor of functional outcome and satisfaction after total knee arthroplasty (TKA). The secondary aims were to identify pre-operative differences in patient demographics, comorbidity and function between patients less than 55 years old compared to those 55 years old and over.

MATERIALS AND METHODS

A retrospective cohort consisting of 2589 patients undergoing a primary TKA was identified from an established arthroplasty database. Patient demographics, comorbidity, Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) and Short Form (SF) 12 scores were collected pre-operatively and 1 year post-operatively. In addition, patient satisfaction was assessed at 1 year. Regression analysis was used to identify independent pre-operative predictors of change in the WOMAC and SF-12 scores, and patient satisfaction.

RESULTS

Patients less than 55 years old were significantly less likely to be satisfied with the overall outcome of their TKA (OR 0.4, p = 0.001). After adjusting for confounding variables age group was not an independent predictor of overall satisfaction with overall outcome (OR 0.71, p = 0.16). Independent predictors of an increased risk of dissatisfaction with the overall outcome at 1 year were depression (OR 0.58, p = 0.008) and worse pre-operative SF-12 MCS (p = 0.04).

CONCLUSION

Age of less than 55 years is not an independent predictor of functional outcome or rate of patient satisfaction after TKA. However, depression and poor mental health are significantly more prevalent in patients less than 55 years old and were independently associated with a lower satisfaction rate.

Predictive Factors for Developing Chronic Pain After Total Knee Arthroplasty

Total knee arthroplasty offers substantial improvements for patients as measured by functional status and quality of life; however, 8% to 34% of patients experience chronic postsurgical pain following surgery (CPSP). In addition to disruption in daily activities of life caused by the pain itself, CPSP has been associated with an overall reduction in quality of life following surgery. Risk factors for CPSP can be broadly defined as potentially modifiable or unlikely modifiable. Unlikely modifiable risks include gender, age, medical comorbidities, and socioeconomic status. Potentially modifiable risks include perioperative pain, physical function, psychological state, surgical factors, and possibly genomics. Understanding risks and the magnitude of their effect on outcomes such as CPSP is desirable because interventions designed to affect these factors may be able to dramatically improve outcomes.