Cost-Effectiveness of Surgical and Nonsurgical Treatments for Unicompartmental Knee Arthritis: A Markov Model

Return to Sport After Unicompartmental Knee Arthroplasty and Patello-Femoral Arthroplasty

BACKGROUND

Data on sports/physical activity participation following unicompartmental knee arthroplasty (UKA) and patello-femoral arthroplasty (PFA) is variable and limited. The purpose of this study was to assess participations, outcomes, and limitations in sports following UKA and PFA.

METHODS

Patients who underwent UKA and PFA at a single institution from 2015 to 2020 were surveyed on sports participation before and after surgery. Data was correlated with perioperative patient characteristics and outcome scores. Among 776 patients surveyed, 356 (50%) patients responded. Of respondents, 296 (83.1%) underwent UKA, 44 (12.6%) underwent PFA, and 16 (4.5%) underwent both UKA/PFA.

RESULTS

Activity participation rates were 86.5, 77.3, and 87.5% five years prior, and 70.9, 61.4, and 75% at one year prior to UKA, PFA, and UKA/PFA, respectively. Return to sports rates were 81.6, 64.7, and 62.3% at mean 4.6 years postoperatively, respectively. The most common activities were recreational walking, swimming, cycling, and golf. Patients returned to a similar participation level for low-impact activities, whereas participation decreased for intermediate- and high-impact activities. Patients participating in activities had higher postoperative Knee Injury and Osteoarthritis Outcome Score Joint Replacement (P < .001), 12-Item Short Form Physical Component Score (P = .045) and Mental Component Score (P = .012). Activity restrictions were reported among 25, 36.4, and 25% of UKA, PFA, and UKA/PFA patients, respectively, and were more commonly self-imposed than surgeon-directed.

CONCLUSIONS

Though UKA patients' postoperative sports participation may improve compared to one year preoperatively, participation for patients surgically treated for isolated osteoarthritis is decreased compared to 5 years preoperatively and varies among patient subsets.

The Cost Effectiveness of Unicompartmental versus Total Knee Arthroplasty

This study examines the potential cost savings for the health system and the community in a broadly accessible model through the increased utilization of unicompartmental knee arthroplasty (UKA) using robotic arm-assisted UKA (raUKA) versus conventional total knee arthroplasty (cTKA). We retrospectively reviewed 240 patients where the first 120 consecutive raUKA performed during this period were matched to 120 cTKAs. Clinical data from the medical records and costs for procedure for each component were collected. Bivariate analyses were performed on the data to determine if there were statistically significant differences by surgery type in clinical outcomes and financial costs. There was a significantly lower cost incurred for raUKA versus cTKA with an average saving of AU$7,179 per case. The operating time (86.0 vs. 75.9 minutes; p = 0.004) was significantly higher for raUKA, but the length of stay was significantly lower (1.8 vs. 4.8 days; p < 0.001). There was a significant difference in the use of opioids between raUKA and cTKA (125.0 morphine equivalent [ME] vs. 522.1 ME, p < 0.001). This study demonstrated that the use of raUKA rather than cTKA in suitably indicated patients may realize significant cost savings.

Economic evaluation of acupuncture as an adjunctive treatment with usual care for mild-to-moderate knee osteoarthritis: A Markov model-based analysis

Background

Collaborative care (CC), in which acupuncture is combined with usual care (UC), improves clinical outcomes and increases costs in knee osteoarthritis (KOA). We evaluated the economic feasibility of CC for Korean female patients with mild-to-moderate KOA by using a cost-effectiveness approach.

Methods

Two alternatives for KOA (1. UC as a comparator; and 2. CC as an intervention) were defined based on clinical guidelines, official Korean statistics, and expert validation. Each alternative was simulated in a Markov model every 6 months for 10 years. Estimates of costs, utilities, and transition probabilities were obtained from official statistics and previous studies. The effectiveness of CC was synthesized from randomized controlled trials. A base-case analysis of a limited societal perspective, univariate sensitivity analysis, and probability sensitivity analysis were performed. An annual discount rate of 4.5% and threshold of 20,000 United States dollar per Quality-adjusted life year (USD/QALY) were applied.

Results

Every incremental cost-effectiveness ratio (ICER) of CC calculated from the analyses was sub-threshold. In the base-case analysis, with a limited societal perspective, the ICER was 11,085 USD/QALY. The ICERs from the univariate sensitivity analyses were -2,577-16,748 USD/QALY. The average ICER in the probability sensitivity analysis was 12,412 USD/QALY. When the threshold surpassed 8,000 USD/QALY, the cost-effectiveness of CC exceeded 50%. The probability was 70.27% when the threshold was 20,000 USD/QALY.

Conclusions

CC for Korean female patients with mild-to-moderate KOA was generally cost-effective. Considering the limitations of the evidence, we propose a re-evaluation using further clinical studies in the future.

Costs and models used in the economic analysis of Total Knee Replacement (TKR): A systematic review

OBJECTIVES

The main objective of this review is to summarize the evidence on the core modelling specifications and methodology on the cost-effectiveness of TKR compared to non-surgical management. Another objective of this study is to synthesize evidence of TKR cost and compare it across countries using purchasing power parity (PPP).

METHODOLOGY

The electronic databases used for this review were MEDLINE (PubMed), Cochrane Central Register of Controlled Trials (CENTRAL), HTAIn repository, Cost effectiveness Analysis (CEA) registry, and Google Scholar. Consolidated Health Economic Evaluation Reporting Standards (CHEERS) was used to assess the validity of the methods and transparency in reporting the results. The Quality of Health Economic Studies (QHES) was used to check the quality of economic evaluation models of the studies included. The cost of TKR surgery from high income and low- or middle-income countries were extracted and converted to single USD ($) using purchasing power parities (PPP) method.

RESULT

Thirty-two studies were included in this review, out of which eight studies used Markov model, five used regression model, one each reported Marginal structure model, discrete simulation model, decision tree and Osteoarthritis Policy Model (OAPol) respectively to assess the cost-effectiveness of TKR. For PPP, twenty-six studies were included in the analysis of TKR cost. The average cost of TKR surgery was the lowest in developing country-India ($3457) and highest in USA ($19568).

CONCLUSION

The findings of this review showed that the Markov model was most widely used in the analysis of the cost effectiveness of TKR. Our review also concluded that the cost of TKR was higher in the developed countries as compared to the developing countries.

Incorporating Expected Outcomes Into Clinical Decision-Making for Total Knee Arthroplasty

OBJECTIVE

Expected outcomes (e.g., expected survivorship after a cancer treatment) have improved decision-making around treatment options in many clinical fields. Our objective was to evaluate the effect of expected values of 3 widely available total knee arthroplasty (TKA) outcomes (risk of serious complications, time to revision, and improvement in pain and function at 2 years after surgery) on clinical recommendation of TKA.

METHODS

The RAND/University of California Los Angeles appropriateness criteria method was used to evaluate the role of the 3 expected outcomes in clinical recommendation of TKA. The expected outcomes were added to 5 established preoperative factors from the modified Escobar appropriateness criteria. The 8 indication factors were used to develop 279 clinical scenarios, and a panel of 9 clinicians rated the appropriateness of TKA for each scenario as inappropriate, inconclusive, and appropriate. Classification tree analysis was applied to these ratings to identify the most influential of the 8 factors in discriminating TKA appropriateness classifications.

RESULTS

Ratings for the 279 appropriateness scenarios deemed 34.4% of the scenarios as appropriate, 40.1% as inconclusive, and 25.5% as inappropriate. Classification tree analyses showed that expected improvement in pain and function and expected time to revision were the most influential factors that discriminated among the TKA appropriateness classification categories.

CONCLUSION

Our results showed that clinicians would use expected postoperative outcome factors in determining appropriateness for TKA. These results call for further work in this area to incorporate estimates of expected pain/function and revision outcomes into clinical practice to improve decision-making for TKA.

Is Surgical Repair With Nerve Allograft More Cost-Effective Than Non-Surgical Management for Persistent Trigeminal Neuropathy? Initial Assessment With Markov Model

PURPOSE

Persistent trigeminal neuropathy (PTN) is associated with high rates of depression, loss of work, and decreased quality of life (QoL). Nerve allograft repair can achieve functional sensory recovery in a predictable manner; however, it bears significant upfront costs. In patients suffering from PTN, is surgical repair with allogeneic nerve graft, when compared to non-surgical therapy, a more cost-effective treatment option?

MATERIALS AND METHODS

A Markov model was constructed with TreeAge Pro Healthcare 2022 (TreeAge Software, Massachusetts) to estimate the direct and indirect costs for PTN. The model ran for 40 years with 1-year-cycles on a 40-year-old model patient with persistent inferior alveolar or lingual nerve injury (S0 to S2+) at 3 months without signs of improvement, and without dysesthesia or neuropathic pain (NPP). The 2 treatment arms were surgery with nerve allograft versus non-surgical management. There were 3 disease states, functional sensory recovery (S3 to S4), hypoesthesia/anesthesia (S0 to S2+), and NPP. Direct surgical costs were calculated using the 2022 Medicare Physician Fee Schedule and verified with standard institutional billing practices. Non-surgical treatment direct costs (follow-up, specialist referral, medications, imaging) and indirect costs (QoL, loss of employment) were determined from historical data and the literature. Direct surgical costs for allograft repair were $13,291. State-specific direct costs for hypoesthesia/anesthesia were $2,127.84 per year, and $3,168.24 for NPP per year. State-specific indirect costs included decreased labor force participation, absenteeism, and decreased QoL.

RESULTS

Surgical treatment with nerve allograft was more effective and had a lower long-term cost. The incremental cost-effectiveness ratio was -10,751.94, indicating surgical treatment should be utilized based on efficiency and cost. With a willingness-to-pay threshold of $50,000, the net monetary benefits of surgical treatment are $1,158,339 compared to $830,654 for non-surgical treatment. With a standard threshold incremental cost-effectiveness ratio of 50,000, the sensitivity analysis shows that surgical treatment would remain the preferred choice based on efficiency even if surgical costs were doubled.

CONCLUSION

Despite high initial costs of surgical treatment with nerve allograft for PTN, surgical intervention with nerve allograft is a more cost-effective treatment option when compared to non-surgical therapy.

Unicompartmental Knee Arthroplasty Is Cost-Effective in an Outpatient Setting

INTRODUCTION

Increasingly, unicompartmental knee arthroplasty (UKA) is being performed on an outpatient basis, with the growing utilization of ambulatory surgery centers (ASCs). The purpose of this study was to compare the costs of UKAs performed in an ASC to UKAs done in a hospital, either on an outpatient or inpatient basis.

METHODS

This study involved three matched groups, each with 50 consecutive patients, undergoing UKA either on an outpatient basis in an ASC or a community hospital, or who were admitted overnight to the same community hospital. Identical perioperative analgesic regimens and care protocols were used in each group. The primary outcomes evaluated included direct facility costs. Secondary outcomes were postoperative complications and readmissions.

RESULTS

Average age, gender ratio, and comorbidities were similar in all three cohorts. Only two patients in the study experienced complications and these were without secondary adverse consequences. Mean costs were substantially reduced when UKAs were performed in an ASC ($9,025) compared to a community hospital on either an outpatient ($12,032) or inpatient basis ($14,542).

CONCLUSION

UKA can be safely performed in the outpatient setting, in appropriately selected patients, at substantial cost savings, particularly when performed in an ASC.

Open Reduction Internal Fixation Versus Distal Femoral Replacement (DFR) for Treatment of OTA/AO 33C Fractures in the Elderly: A Review of Functional Outcomes and Cost Analysis

OBJECTIVES

To determine the economic cost associated with the treatment of OTA/AO 33C fractures in patients older than 65 years of age using open reduction internal fixation (ORIF) or DFR and to assess the perioperative outcomes of elderly patients treated surgically following OTA/AO 33C fractures.

DESIGN

Retrospective cohort over a 10-year period.

SETTING

A single level-1 trauma center.

PARTICIPANTS AND INTERVENTION

Thirty-nine patients 65 or older with OTA/AO 33C fractures who underwent treatment with ORIF (n = 27) or DFR (n = 12) were included.

MAIN OUTCOME MEASUREMENTS

Direct cost associated with surgical treatment along with LOS, functional outcomes, patient-reported outcomes, and all-cause reoperation.

RESULTS

Index procedure costs were as follows: DFR: $ 61,259 vs. ORIF: $44,490 (P = 0.056). Five (20%) ORIF patients required revision versus one (8%) in the DFR group. Total cost when including reoperation resulted in DFR being $14,805 more costly, which was not significant. Hospital LOS was similar between groups; however, convalescent LOS was longer in ORIF patients (43.2 vs. 23.1 days, P = 0.02).

CONCLUSION

This study demonstrates that there is no significant difference in overall cost between ORIF and DFR when all costs are considered. A larger portion of DFR patients were able to mobilize postoperatively, with subacute length of stay being longer in ORIF patients. A multicenter trial is warranted to determine optimal treatment for this complex problem.

LEVEL OF EVIDENCE

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

Improved accuracy and reproducibility of a novel CT-free robotic surgical assistant for medial unicompartmental knee arthroplasty compared to conventional instrumentation: a cadaveric study

PURPOSE

Alignment errors in medial unicompartmental knee arthroplasty (UKA) predispose to premature implant loosening and polyethylene wear. The purpose of this study was to determine whether a novel CT-free robotic surgical assistant improves the accuracy and reproducibility of bone resections in UKA compared to conventional manual instrumentation.

METHODS

Sixty matched cadaveric limbs received medial UKA with either the ROSA^® Partial Knee System or conventional instrumentation. Fifteen board-certified orthopaedic surgeons with no prior experience with this robotic application performed the procedures with the same implant system. Bone resection angles in the coronal, sagittal and transverse planes were determined using optical navigation while resection depth was obtained using calliper measurements. Group comparison was performed using Student's t test (mean absolute error), F test (variance) and Fisher's exact test (% within a value), with significance at p < 0.05.

RESULTS

Compared to conventional instrumentation, the accuracy of bone resections with CT-free robotic assistance was significantly improved for all bone resection parameters (p < 0.05), other than distal femoral resection depth, which did not differ significantly. Moreover, the variance was significantly lower (i.e. fewer chances of outliers) for five of seven parameters in the robotic group (p < 0.05). All values in the robotic group had a higher percentage of cases within 2° and 3° of the intraoperative plan. No re-cuts of the proximal tibia were required in the robotic group compared with 40% of cases in the conventional group.

CONCLUSION

The ROSA^® Partial Knee System was significantly more accurate, with fewer outliers, compared to conventional instrumentation. The data reported in our current study are comparable to other semiautonomous robotic devices and support the use of this robotic technology for medial UKA.

LEVEL OF EVIDENCE

Cadaveric study, Level V.

The Cost-Effectiveness of Tibial Metaphyseal Cones in Revision Total Knee Arthroplasty

BACKGROUND

The purpose of this study is to evaluate the cost-effectiveness of tibial cones in revision total knee arthroplasty.

METHODS

A Markov model was used for cost-effectiveness analysis. The average cone price was obtained from Orthopedic Network News. The average cone aseptic loosening rate was determined by literature review. Hospitalization costs and baseline re-revision rates were calculated using the PearlDiver Database.

RESULTS

The maximum cost-effective cone price varied from $3514 at age 40 to $648 at age 90, compared to the current average selling price of $4201. Cones became cost-effective with baseline aseptic loosening rates of 0.89% annually at age 40 to 4.38% annually at age 90, compared to the current average baseline loosening rate of 0.76% annually.

CONCLUSION

For the average patient, tibial cones are not cost-effective, but may become so at lower prices, in younger patients, or in patients at substantially increased risk of aseptic loosening.

Prior Anterior Cruciate Ligament Reconstruction Does Not Compromise the Functional Outcomes of Medial Unicompartmental Knee Arthroplasty Although Revision for Progressive Arthritis May Occur Earlier

BACKGROUND

Anterior cruciate ligament (ACL) deficiency is commonly considered a contraindication for unicompartmental knee arthroplasty (UKA). The purpose of this study is to compare the outcomes of UKA after prior ACL reconstruction (rACL cohort) to UKA with an intact native ACL (nACL cohort).

METHODS

Forty-five patients from 3 institutions who underwent medial UKA after prior rACL were matched by age, gender, preoperative function scores, and body mass index to 90 patients who underwent UKA with an intact nACL. Primary outcomes were Knee Injury and Osteoarthritis Outcome Score for Joint Replacement, Oxford Knee Scores, Knee Society Functional Scores, and Kellgren-Lawrence scores in the unresurfaced, lateral tibiofemoral compartment. Secondary outcomes were postoperative complications and the need for revision to TKA.

RESULTS

At a mean of 3.6 years, all PROMs improved significantly with no differences identified between groups. The incidence of revision TKA was similar between cohorts (P = 1.00); however, the mean time to revision for progressive osteoarthritis was 4.0 years in the nACL group and 2.2 years in the rACL group. Twenty percent of rACL patients had a postoperative complication compared to 8% in the nACL group. Despite presenting with a similar degree of lateral arthritis, a greater percentage of patients developed Kellgren-Lawrence scores of ≥3 in the rACL cohort (9%) than in the nACL cohort (0%).

CONCLUSION

A previously reconstructed ACL does not appear to compromise the short-term functional outcomes of UKA; however, there is a higher rate of minor complications and progression of lateral compartment arthritis, which should be considered with patients in the shared decision process.

Joint awareness after unicompartmental knee arthroplasty and total knee arthroplasty: a systematic review and meta-analysis of cohort studies

PURPOSE

The purpose of this systematic review and meta-analysis is to evaluate the joint awareness after unicompartmental knee arthroplasty (UKA) and total knee arthroplasty (TKA). It was hypothesized that patients with UKA could better forget about their artificial joint in comparison to TKA.

METHODS

A search of major literature databases and bibliographic details revealed 105 studies evaluating forgotten joint score in UKA and TKA. Seven studies found eligible for this review were assessed for risk of bias and quality of evidence using the Newcastle-Ottawa Scale. The forgotten joint score (FJS-12) was assessed at 6 months, 1 year, and 2 years.

RESULTS

The mean FJS-12 at 2 years was 82.35 in the UKA group and 74.05 in the TKA group. Forest plot analysis of five studies (n = 930 patients) revealed a mean difference of 7.65 (95% CI: 3.72, 11.57, p = 0.0001; I² = 89% with p < 0.0001) in FJS-12 at 2 years. Further sensitivity analysis lowered I² heterogeneity to 31% after exclusion of the study by Blevin et al. (MD 5.88, 95%CI: 3.10, 8.66, p < 0.0001). A similar trend of differences in FJS-12 between the groups was observed at 6 months (MD 32.49, 95% CI: 17.55, 47.43, p < 0.0001) and at 1 year (MD 25.62, 95% CI: 4.26, 46.98, p = 0.02).

CONCLUSIONS

UKA patients can better forget about their artificial joint compared to TKA patients.

LEVEL OF EVIDENCE

III.

Robotic Assistance in Unicompartmental Knee Arthroplasty Results in Superior Early Functional Recovery and Is More Likely to Meet Patient Expectations

Robotic technology has reduced the errors of implant alignment in unicompartmental knee arthroplasty (UKA), but its impact on functional recovery after UKA is poorly defined. The purpose of this study was to compare early functional recovery, pain levels, and satisfaction in UKA performed with either robotic assistance or conventional methods. A retrospective analysis was performed on 89 matched consecutive patients who underwent outpatient UKA by a single physician using either conventional instruments (n = 39) or robotic methods (n = 50), with otherwise identical perioperative protocols. Outcomes studied included Lower Extremity Functional Score (LEFS), new Knee Society Score (KSS), Knee Injury and Osteoarthritis Outcome Score for Joint Replacement (KOOS-JR.), VR/SF-12, Visual Analog Scale (VAS) pain scores, and perioperative opioid consumption. Patients in the robotic cohort had superior early functional outcomes, with greater LEFS (conventional = 23; robotic = 31) at 1 week post-op (p=0.015) and KOOS-JR (conventional = 74; robotic = 81) at up to 6 months post-op (p=0.037); these two values remained statistically significant after mixed-model regression analysis (p=0.010; p=0.023), respectively. At 1 year post-op, expectations were more likely to be met in those who received robotic assistance (p=0.06). No differences were reported with respect to postoperative opioid usage (p=0.320), reoperations (p=1.00), and complications (p=0.628). Robotic-assisted UKA resulted in more rapid recovery and less early postoperative pain and were more likely to meet expectations than conventional UKA, although functional differences equilibrated by 1 year postoperatively. Further follow-up is necessary to determine if implant durability is impacted by robotics.

Despite Equivalent Medicare Reimbursement, Facility Costs for Outpatient Total Knee Arthroplasty Are Higher Than Unicompartmental Knee Arthroplasty

BACKGROUND

With the recent removal of total knee arthroplasty (TKA) from the Centers for Medicare and Medicaid Services (CMS) Inpatient Only list, facility reimbursement for outpatient TKA now falls under the Outpatient Prospective Payment System at the same rate as unicompartmental knee arthroplasty (UKA). The purpose of this study was to compare true facility costs of patients undergoing outpatient TKA with those undergoing UKA.

METHODS

We reviewed a consecutive series of 2310 outpatient TKA and 231 UKA patients from 2018 to 2019. Outpatient status was defined as a hospital stay of less than 2 midnights. Facility costs were calculated using a time-driven, activity-based costing algorithm. Implants, supplies, medications, and personnel costs were compared between outpatient TKA and UKA patients. A multivariate analysis was performed to control for confounding medical and demographic variables.

RESULTS

When compared with patients undergoing UKA, outpatient TKA patients had higher implant costs ($3403 vs $3081; P < .001) and overall hospital costs ($6350 vs $5594; P < .001). Outpatient TKA patients had a greater length of stay (1.2 vs 0.5 days; P < .001) and greater postoperative personnel costs ($783 vs $166; P < .001) than UKA patients. When controlling for comorbidities, outpatient TKA was associated with a $803 (P < .001) increase in overall facility costs compared with UKA.

CONCLUSION

Despite equivalent reimbursement from CMS as UKA, outpatient TKA has increased facility costs to the hospital. Although implant costs can vary greatly by institution, CMS should consider appropriately reimbursing outpatient TKA for the additional personnel costs when compared with UKA.

Cost Comparison of Botulinum Toxin Injections Versus Surgical Treatment in Pediatric Patients With Cerebral Palsy: A Markov Model

PURPOSE

The purpose of this study was to compare the cost-effectiveness of surgical release to botulinum toxin injections in the treatment of upper-extremity (UE) cerebral palsy (CP).

METHODS

A Markov transition-state model was developed to assess the direct and indirect costs as well as accumulated quality-adjusted life-years associated with surgery (surgery group) and continuous botulinum toxin injections (botulinum group) for the treatment of UE CP in children aged 7 to 12 years. Direct medical costs were obtained from institutional billing departments. The number of parental missed workdays associated with each treatment was estimated and previously published regressions were used to calculate indirect costs associated with missed work. Total costs, cost-effectiveness, and incremental cost-effectiveness ratios were calculated. Incremental cost-effectiveness ratios and willingness to pay thresholds were used to make decisions regarding society's willingness to pay for the incremental cost of each treatment given the incremental benefit.

RESULTS

The surgery group demonstrated lower direct, indirect, and total costs compared with the botulinum group. Direct costs were $29,250.50 for the surgery group and $50,596.00 for the botulinum group. Indirect costs were $9,467.46 for the surgery group and $44,428.60 for the botulinum group. Total costs were $38,717.96 for the surgery group and $95,024.60 for the botulinum group, a difference of $56,306.64. The incremental cost-effectiveness ratio was -$42,019.88, indicating that surgery is a less costly and more effective treatment and that botulinum injections fall outside the societal willingness to pay threshold. Excluding indirect costs associated with parental missed work during home occupational therapy did not have a significant impact on the model.

CONCLUSIONS

Surgery is associated with lower direct, indirect, and total costs, as well as a greater number of accumulated quality-adjusted life-years. Surgery provides a greater benefit at a lower cost, which suggests that botulinum injections should be used sparingly in this population. Treatment with surgery could represent savings of $5.6 to $11.3 billion annually in the United States.

TYPE OF STUDY/LEVEL OF EVIDENCE

Economic/Decision Analysis II.

Radiological outcomes following manual and robotic-assisted unicompartmental knee arthroplasty

Aims

The purpose of this study was to compare the radiological outcomes of manual versus robotic-assisted medial unicompartmental knee arthroplasty (UKA).

Methods

Postoperative radiological outcomes from 86 consecutive robotic-assisted UKAs (RAUKA group) from a single academic centre were retrospectively reviewed and compared to 253 manual UKAs (MUKA group) drawn from a prior study at our institution. Femoral coronal and sagittal angles (FCA, FSA), tibial coronal and sagittal angles (TCA, TSA), and implant overhang were radiologically measured to identify outliers.

Results

When assessing the accuracy of RAUKAs, 91.6% of all alignment measurements and 99.2% of all overhang measurements were within the target range. All alignment and overhang targets were simultaneously met in 68.6% of RAUKAs. When comparing radiological outcomes between the RAUKA and MUKA groups, statistically significant differences were identified for combined outliers in FCA (2.3% vs 12.6%; p = 0.006), FSA (17.4% vs 50.2%; p < 0.001), TCA (5.8% vs 41.5%; p < 0.001), and TSA (8.1% vs 18.6%; p = 0.023), as well as anterior (0.0% vs 4.7%; p = 0.042), posterior (1.2% vs 13.4%; p = 0.001), and medial (1.2% vs 14.2%; p < 0.001) overhang outliers.

Conclusion

Robotic system navigation decreases alignment and overhang outliers compared to manual UKA. Given the association between component placement errors and revision in UKA, this strong significant improvement in accuracy may improve implant survival.

Level of Evidence: III

Cite this article: Bone Jt Open 2021;2-3:191–197.

How Are We Measuring Cost-Effectiveness in Total Joint Arthroplasty Studies? Systematic Review of the Literature

BACKGROUND

As volumes of total hip arthroplasty (THA) and total knee arthroplasty (TKA) continue to rise, it is important to understand their economic impact. No systematic review on cost-effectiveness of THA/TKA has been performed since 2016 despite recent changes in the healthcare environment. The purpose of the study is to provide a contemporary analysis of the cost-effectiveness of total joint arthroplasty and the use of quality-adjusted life years (QALYs).

METHODS

A systematic review was performed from 2005 to 2020. Online databases (OVID Medline, PubMed, Cost-Effectiveness Analysis Registry, Google Scholar, Elton B. Stephens Co) were queried to identify economic analyses that evaluated the cost-effectiveness of THA/TKA.

RESULTS

In total, 38 studies met the screening criteria. Study designs were primarily Markov models (68%), cohort studies (16%), and randomized trials (8%). Most studies adopted either a societal perspective (45%) or a health system perspective (39%). Analysis revealed that THA/TKA was strongly cost-effective compared to nonsurgical treatment. THA/TKA procedures that were not delayed were more cost-effective than delayed intervention. The majority of studies used QALYs as the primary quality metric (82%); in all these studies there was a significant improvement in QALYs gained.

CONCLUSION

Given the high economic impact of arthroplasty, ongoing assessment of cost-effectiveness is needed. Twenty-four percent of studies included in this systematic review were published in the last 4 years of this 15-year study period, highlighting the need for continuous assessment of aggregate data. Future studies should incorporate the cost-effectiveness of THA and TKA with respect to the work-value provided by surgeon providers to support health policy and reimbursement.

Modelling the cost-effectiveness of total knee arthroplasty: A systematic review

Objective

Osteoarthritis causes a significant healthcare burden and the number of total knee arthroplasty (TKA) procedures is predicted to increase significantly in the coming years. We conducted a systematic review to assess the scope and quality of all current TKA cost-effectiveness analysis (CEA) studies, identify trends, and identify areas for improvement.

Methods

An electronic database search of MEDLINE, Embase, the CEA registry and Scopus was used to identify all CEA studies where TKA was used with a comparator. Studies were included from January 1, 1997 to February 2, 2020. The Quality of Health Economic Analysis Studies (QHES) instrument was used to assess their quality. Thirty-three studies were included that offered both a QALY and cost calculation. The main findings, incremental-cost effectiveness ratios and other important study characteristics were then ascertained, and trends identified.

Results

Certain surgical interventions were suggested to be more cost-effective than TKA. This included unicompartmental knee arthroplasty for unicompartmental osteoarthritis, computer-assisted TKA compared to conventional TKA, and resurfacing the patella compared to no resurfacing. TKA was more cost-effective compared to non-operative management regardless of specific patient variables.

Conclusions

The analyses of the CEAs included in the study have to be interpreted with caution. Overall, certain surgical methods within TKA and alternative methods to TKA appear to be favoured for treating particular knee osteoarthritic conditions due to their suggested greater cost-effectiveness but this should be interpreted within local contexts. Our results should help guide future policy-making as healthcare associated costs continue to rise.

Does resurfacing of asymptomatic full-thickness localized articular defects of the trochlea influence the outcome following unicompartmental knee arthroplasty of the medial compartment?: A retrospective cohort study with minimum seven-year follow-up

BACKGROUND

Patellofemoral joint (PFJ) degeneration has been found not to affect outcome following medial unicompartmental knee arthroplasty (UKA). However, PFJ disease occasionally presents as isolated trochlear cartilage lesions, with little available evidence regarding treatment options or necessity. We evaluated the effectiveness of concomitant trochlear resurfacing in patients undergoing medial UKA with asymptomatic trochlear lesions.

METHODS

We included 60 patients undergoing medial UKA with an associated full thickness lesion of the trochlea. A fixed bearing UKA implant (PKR™, Stryker, Warsaw, IND) was used in all cases. In 30 patients, trochlear lesions were resurfaced with a HemiCAP® PF Classic (HemiCAP® PFC) implant (Arthrosurface, Franklin, MA). Outcome measures included VAS-, KOOS-, WOMAC-, SF-36 scores and radiological assessment.

RESULTS

Average length of follow-up was 97.4 months (range: 88-106 months). Both groups showed significant improvement for all clinical scores post-operatively compared to pre-operatively (p < 0.001 for all). The UKA group showed a better VAS score at all follow-up moments (p < 0.01 for all), but no differences were found between both groups at all time points for other outcome measures. None of the HemiCAP® PFC implants needed to be revised within the timeframe of the study.

CONCLUSIONS

In this retrospective cohort study, we found a 100% survivorship of the HemiCAP® PFC implant at an average eight-year follow-up. However, no clinical benefits were found in performing trochlear resurfacing in conjunction with medial UKA for asymptomatic end-stage trochlear cartilage lesions. Therefore, these lesions can be safely ignored when performing a medial UKA.

High Prevalence of Radiographic Outliers and Revisions with Unicompartmental Knee Arthroplasty

BACKGROUND

Alignment outcomes and their impact on implant survival following unicompartmental knee arthroplasty (UKA) are unclear. The purpose of this study was to assess the implant survival and radiographic outcomes after UKA as well as the impact of component alignment and overhang on implant survival.

METHODS

We performed a retrospective analysis of 253 primary fixed-bearing and mobile-bearing medial UKAs from a single academic center. All UKAs were performed by 2 high-volume fellowship-trained arthroplasty surgeons. UKAs comprised <10% of their knee arthroplasty practices, with an average of 14.2 medial UKAs per surgeon per year. Implant survival was assessed. Femoral coronal (FCA), femoral sagittal (FSA), tibial coronal (TCA), and tibial sagittal (TSA) angles as well as implant overhang were radiographically measured. Outliers were defined for FCA (>±10° deviation from neutral), FSA (>15° of flexion), TCA (>±5° deviation from neutral), and TSA (>±5° deviation from 7°). "Far outliers" were an additional >±2° of deviation. Outliers for overhang were identified as >3 mm for anterior overhang, >2 mm for posterior overhang, and >2 mm for medial overhang.

RESULTS

Among patients with a failed UKA, revision was performed at an average of 3.7 years (range, 0.03 to 8.7 years). The cumulative revision rate was 14.2%. Kaplan-Meier survival analysis demonstrated 5 and 10-year survival rates of 88.0% (95% confidence interval [CI] = 82.0% to 91.0%) and 70.0% (95% CI = 56.0% to 80.0%), respectively. Only 19.0% (48) of the UKAs met target alignment for all 4 alignment measures, and only 72.7% (184) met all 3 targets for overhang. Only 11.9% (30) fell within all alignment and overhang targets. The risk of implant failure was significantly impacted by outliers for FCA (failure rate = 15.4%, p = 0.036), FSA (16.2%, p = 0.028), TCA (17.9%, p = 0.020), and TSA (15.2%, p = 0.034) compared with implants with no alignment or overhang errors (0%); this was also true for far outliers (p < 0.05). Other risk factors for failure were posterior overhang (failure rate = 25.0%, p = 0.006) and medial overhang (38.2%, p < 0.001); anterior overhang was not a significant risk factor (10.0%, p = 0.090).

CONCLUSIONS

The proportions of UKA revisions and alignment outliers were greater than expected, even among high-volume arthroplasty surgeons performing an average of 14.2 UKAs per year (just below the high-volume UKA threshold of 15). Alignment and overhang outliers were significant risk factors for implant failure.

LEVEL OF EVIDENCE

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

Providing Value in Fracture Care: Academic Versus Private Setting

Although the science of fracture care transcends the setting, the delivery of value may be dramatically different depending on the practice situation. Compared to our colleagues specializing in total joint arthroplasty, trauma surgeons have a greater challenge demonstrating increased quality relative to the cost of care. Although most orthopedic surgeons are in private practice, their individual practice settings vary significantly. Generally speaking, private groups with dynamic and forward-thinking leadership can seize opportunity to increase value in fracture care, and nimble action can improve value for the patient and the practice. Academic medical centers have synergies to enhance integrated medical care, and the tripartite mission of education, research and patient care lend themselves to increasing value. In either setting, leadership in orthopedic surgery can enhance value in fracture care.

The Impact of Surgeon Volume and Training Status on Implant Alignment in Total Knee Arthroplasty

BACKGROUND

Implant malalignment may predispose patients to prosthetic failure following total knee arthroplasty (TKA). A more thorough understanding of the surgeon-specific factors that contribute to implant malalignment following TKA may uncover actionable strategies for improving implant survival. The purpose of this study was to determine the impact of surgeon volume and training status on malalignment.

METHODS

In this retrospective multicenter study, we performed a radiographic analysis of 1,570 primary TKAs performed at 4 private academic and state-funded centers in the U.S. and U.K. Surgeons were categorized as high-volume (≥50 TKAs/year) or low-volume (<50 TKAs/year), and as a trainee (fellow/resident under the supervision of an attending surgeon) or a non-trainee (attending surgeon). On the basis of these designations, 3 groups were defined: high-volume non-trainee, low-volume non-trainee, and trainee. The postoperative medial distal femoral angle (DFA), medial proximal tibial angle (PTA), and posterior tibial slope angle (PSA) were radiographically measured. Outlier measurements were defined as follows: DFA, outside of 5° ± 3° of valgus; PTA, >±3° deviation from the neutral axis; and PSA, <0° or >7° of flexion for cruciate-retaining or <0° or >5° of flexion for posterior-stabilized TKAs. "Far outliers" were defined as measurements falling >± 2° outside of these ranges. The proportions of outliers were compared between the groups using univariate and multivariate analyses.

RESULTS

When comparing the high and low-volume non-trainee groups using univariate analysis, the proportions of knees with outlier measurements for the PTA (5.3% versus 17.4%) and PSA (17.4% versus 28.3%) and the proportion of total outliers (11.8% versus 20.7%) were significantly lower in the high-volume group (all p < 0.001). The proportions of DFA (1.9% versus 6.5%), PTA (1.8% versus 5.7%), PSA (5.5% versus 12.6%), and total far outliers (3.1% versus 8.3%) were also significantly lower in the high-volume non-trainee group (all p < 0.001). Compared with the trainee group, the high-volume non-trainee group had significantly lower proportions of DFA (12.6% versus 21.6%), PTA (5.3% versus 12.0%), PSA (17.4% versus 33.3%), and total outliers (11.8% versus 22.3%) (all p < 0.001) as well as DFA (1.9% versus 3.9%; p = 0.027), PSA (5.5% versus 12.6%; p < 0.001), and total far outliers (3.1% versus 6.4%; p = 0.004). No significant differences were identified when comparing the low-volume non-trainee group and the trainee group, with the exception of PTA outliers (17.4% versus 12.0%; p = 0.041) and PTA far outliers (5.7% versus 2.6%; p = 0.033). Findings from multivariate analysis accounting for the effects of patient age, body mass index, and individual surgeon demonstrated similar results.

CONCLUSIONS

Low surgical volume and trainee status were risk factors for outlier and far-outlier malalignment in primary TKA, even when accounting for differences in individual surgeon and patient characteristics. Trainee surgeons performed similarly, and certainly not inferiorly, to low-volume non-trainee surgeons. Even among high-volume non-trainees, the best-performing cohort in our study, the proportion of TKA alignment outliers was still high.

LEVEL OF EVIDENCE

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

The patient results and satisfaction of knee arthroplasty in a validated grading system

INTRODUCTION

The validated Knee Osteoarthritis Grading System (KOGS) was implemented and clinical results were compared with patient satisfaction data and implant survivorship in a multi-centre study with surgeons familiar with unicompartmental knee arthroplasty (UKA), patellofemoral arthroplasty (PFA) and total knee arthroplasty (TKA). This is also the first study to evaluate the prevalence of UKA and TKA in consecutive osteoarthritis (OA) knee arthroplasties assessed by this system..

METHOD

A consecutive cohort of knees was gathered at three different institutions as categorized by KOGS and surgically treated with the recommended implant unless clinical reasons or patient preference precluded such an option. One thousand one hundred seventy-seven consecutive knees were evaluated including 311 TKA (26%), 695 medial UKA (59%), 154 lateral UKA (13%) and 17 PFA (2%) and the results of the categories evaluated with the Oxford Knee Score (OKS) and the complications reflected in the different categories.

RESULTS

The failure rate of the UKA (3.5%) or TKA (1.6%) is not higher than accepted results in the literature and the difference in complications is negligible between the UKA (72%) and TKA (26%) cohorts. Revision of a UKA to a TKA as an endpoint was 0.58% with ipsilateral progression at 0.8% over a period of five to 84 months (mean follow-up of 36 months) despite the 'excessive' proportion of UKA in this cohort. The Oxford Score improvement is significant in TKA and UKA and contributes to the acceptable outcomes (The OKS for TKA improved from 20 pre-operatively to 36 post-operatively and the UKA improved from 22 pre-operatively to 39 post-operatively).

CONCLUSION

KOGS achieves acceptable early survival and functional results when implemented and is a suitable tool for identifying the preferred implant as was validated.