Do modern total knee replacements offer better value for money? A health economic analysis

Cost-utility analysis of total knee arthroplasty using 10-year data from a randomised controlled trial: Implant design influences quality-adjusted life year gain

BACKGROUND

The aim of this study was to perform a cost-utility analysis for total knee arthroplasty (TKA) over a 10-year follow up period.

METHODS

Two-hundred and twelve patients were randomised to receive either a Kinemax or a Triathlon TKA. Patients were assessed pre-operatively, and at 6 months, and 1, 3, 7 and 10 years postoperatively. The costs of the primary and revision surgery were accounted for. One-year quality-adjusted life year (QALY) gain was used to estimate 10-year gains using the established annual health gain discounts.

RESULTS

Forty-eight patients died and eight were revised during the follow up period. Overall QALY gain per patient over the 10-year period was 2.594 and the cost per patient was £6559, which resulted in a cost per QALY of £2761 at 10 years. The Triathlon group had a significantly greater QALY gain compared with the Kinemax (mean difference (MD) 0.53, 95% CI 0.03-1.03, P = 0.02), which resulted in a cost per QALY for the Triathlon group of £2521 compared with £3107 for the Kinemax group at 10 years. The 5% annual discount resulted in a significantly lower QALY gain (MD 0.135, 95% CI 0.201-0.354, P = 0.002), whereas the 3.5% annual discount resulted in non-significant difference in QALY gain compared with the actual gain (MD 0.021, 95% CI -0.084 to 0.077, P = 0.292).

CONCLUSIONS

TKA was a cost-effective intervention, and the Triathlon was associated with a greater cost effectiveness at 10 years. The 3.5% annual discounts for QALY gain would seem to be the most accurate, with an underestimation being observed with the 5% discount.

The Effect of Preoperative Rehabilitation Training on the Early Recovery of Joint Function after Artificial Total Knee Arthroplasty and Its Effect Evaluation

Objective

To study the effect of preoperative rehabilitation training on the rehabilitation of patients after total knee arthroplasty.

Methods

A total of 120 patients diagnosed with knee osteoarthritis and undergoing total knee arthroplasty were selected and divided into experimental group and control group according to a random number table, with 60 cases in each group. The control group only carried out routine clinical nursing before the operation, and the experimental group used the formulated preoperative rehabilitation training method based on the control group for training. By comparing the visual analogue score (VAS), keen society score (KSS), postoperative time to get out of bed for the first time, patient satisfaction, and other related indicators between the two groups of patients, the recovery of keen joint function of patients after surgery was evaluated.

Results

The visual analogue scale (VAS) of the experimental group was significantly lower than that of the experimental group at three days after operation. The keen society score (KSS) of the experimental group was significantly better than that of the control group at three days after surgery and one month after surgery. The time to get out of bed for the first time after operation in the experimental group (44.93 ± 13.63) was significantly less than that in the control group (78.33 ± 13.52). The patient satisfaction of the experimental group was significantly higher than that of the control group (88.30 ± 3.61). The above statistical results were all p < 0.05 of the two groups, and the differences were statistically significant.

Conclusion

Preoperative rehabilitation training can significantly reduce the pain of patients after knee replacement, improve the functional state of knee joints, shorten the time to get out of bed for the first time after surgery, and win the best recovery opportunity, which can better improve patient satisfaction in hospitalization and improve medical care services level.

Total Hip and Knee Arthroplasties Are Highly Cost-Effective Procedures: The Importance of Duration of Follow-Up

BACKGROUND

Total hip and knee arthroplasties (THA/TKA) are clinically effective but high cost procedures. The aim of this study is to perform a cost-effectiveness analysis of THA and TKA in the New Zealand (NZ) healthcare system.

METHODS

Data were collected from 713 patients undergoing THA and 520 patients undergoing TKA at our local public hospital. SF-6D utility values were obtained from participants preoperatively and 1-year postoperatively, and deaths and any revision surgeries from patient records and the New Zealand Joint Registry at minimum 8-year follow-up. A continuous-time state-transition simulation model was used to estimate costs and health gains to 15 years. Quality-adjusted life years (QALYs), treatment costs, and incremental cost-effectiveness ratios (ICERs) were calculated to determine cost effectiveness. ICERs below NZ gross domestic product (GDP; NZ$60 600) and 0.5 times GDP per capita were considered "cost effective" and "highly cost effective" respectively.

RESULTS

Cumulative health gains were 2.8 QALYs (THA) and 2.3 QALYs (TKA) over 15 years. Cost effectiveness improved from ICERs of NZ$74,400 (THA) and NZ$93,000 (TKA) at 1 year to NZ$6000 (THA) and NZ$7500 (TKA) at 15 years. THA and TKA were cost effective after 2 years and highly cost effective after 3 years. QALY gains and cost effectiveness were greater in patients with worse preoperative functional status and younger age.

CONCLUSION

THA and TKA are highly cost-effective procedures over longer term horizons. Although preoperative status and age were associated with cost effectiveness, both THA and TKA remained cost effective in patients with less severe preoperative scores and older ages.

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.

The Relationship Between Preoperative Oxford Hip and Knee Score and Change in Health-Related Quality of Life After Total Hip and Total Knee Arthroplasty: Can It Help Inform Rationing Decisions?

Background

In countries with publicly funded health care, there is an increasing need for explicit rationing for total joint arthroplasty (TJA). The Oxford Hip and Knee Scores (OHS/OKS) have been used to set access thresholds for TJA despite not being developed for that purpose. The aim of this study was to determine whether preoperative OHS/OKS can aid rationing decisions by investigating the changes in general health-related quality of life after TJA.

Methods

OHS/OKS, Short Form-12, and Short Form-6D (SF-6D) scores were collected preoperatively and at 1 year postoperatively in a cohort of patients undergoing total hip arthroplasty (THA; n = 713) and total knee arthroplasty (TKA; n = 520). The association between preoperative OHS/OKS and postoperative score and the change in OHS/OKS and SF-6D was investigated, adjusting for age and gender.

Results

The mean Oxford scores improved from 13.9 to 40.7 (OHS) and 15.6 to 37.4 (OKS). The mean SF-6D improved after THA (0.53 to 0.80) and TKA (0.56 to 0.78) (all P < .0001). Poorer preoperative Oxford scores were associated with poorer postoperative OHS/OKS and SF-6D but larger improvements. For every 5 points lower preoperative OHS/OKS, the postoperative SF-6D score was worse by a margin of 0.019 (THA) and 0.023 (TKA).

Conclusions

Preoperative OHS/OKS can help inform rationing decisions. A lower preoperative OHS/OKS will result in greater gains but a lower final outcome score in general health-related quality of life.

Comparative clinical and cost analysis between surgical and non-surgical intervention for knee osteoarthritis

OBJECTIVE

To evaluate the management and costs of osteoarthritis of the knee (OAK), a progressive joint disease due to bone and cartilage degeneration, with significant personal and societal impact.

METHODS

We prospectively analyzed the clinical outcomes and quantifiable cumulative direct costs of patients with OAK referred to our multidisciplinary OA program over a two year time period. One hundred thirty-one subjects were assessed. All demonstrated radiographic criteria for moderate to severe OAK. Western Ontario McMaster Osteoarthritis Index (WOMAC), Minimal Clinically Important Improvement (MCII), and change in BMI were recorded and analyzed. Total medical and surgical direct costs for all subjects during the two year time period were determined.

RESULTS

Five patients underwent total joint replacement during the two years of study. Among the group as a whole, a significant overall improvement in WOMAC scores was noted at the two year time point follow-up. After dividing the group into tertiles by baseline WOMAC scores, 46% achieved MCII. Significant weight loss was noted for individuals with baseline BMI of > 30. As all patients were considered "de facto" surgical candidates at referral, an average net savings of $9551.10 of direct costs per patient, or a potential total of $1,203,438.60 for the entire group, could be inferred as a result of medical as opposed to surgical management.

CONCLUSION

These findings support the benefits of multidisciplinary medical management for patients with significant OAK. This approach is clinically beneficial and may provide significant cost savings. Such models of care can substantially improve the long-term outcome of this highly prevalent condition and reduce societal and financial burdens.

Preferred Single-Vendor Program for Total Joint Arthroplasty Implants: Surgeon Adoption, Outcomes, and Cost Savings

BACKGROUND

In total joint arthroplasty, variation in implant use can be driven by vendor relationships, surgeon preference, and technological advancements. Our institution developed a preferred single-vendor program for primary hip and knee arthroplasty. We hypothesized that this initiative would decrease implant costs without compromising performance on quality metrics.

METHODS

The utilization of implants from the preferred vendor was evaluated for the first 12 months of the contract (September 1, 2017, to August 31, 2018; n = 4,246 cases) compared with the prior year (September 1, 2016, to August 31, 2017; n = 3,586 cases). Per-case implant costs were compared using means and independent-samples t tests. Performance on quality metrics, including 30-day readmission, 30-day surgical site infection (SSI), and length of stay (LOS), was compared using multivariable-adjusted regression models.

RESULTS

The utilization of implants from the preferred vendor increased from 50% to 69% (p < 0.001), with greater use of knee implants than hip implants from the preferred vendor, although significant growth was seen for both (from 62% to 81% for knee, p < 0.001; and from 38% to 58% for hip, p < 0.001). Adoption of the preferred-vendor initiative was greatest among low-volume surgeons (from 22% to 87%; p < 0.001) and lowest among very high-volume surgeons (from 61% to 62%; p = 0.573). For cases in which implants from the preferred vendor were utilized, the mean cost per case decreased by 23% in the program's first year (p < 0.001), with an associated 11% decrease in the standard deviation. Among all cases, there were no significant changes with respect to 30-day readmission (p = 0.449) or SSI (p = 0.059), while mean LOS decreased in the program's first year (p < 0.001).

CONCLUSIONS

The creation of a preferred single-vendor model for hip and knee arthroplasty implants led to significant cost savings and decreased cost variability within the program's first year. Higher-volume surgeons were less likely to modify their implant choice than were lower-volume surgeons. Despite the potential learning curve associated with changes in surgical implants, there was no difference in short-term quality metrics.

LEVEL OF EVIDENCE

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

Do outcomes reported in randomised controlled trials of joint replacement surgery fulfil the OMERACT 2.0 Filter? A review of the 2008 and 2013 literature

BACKGROUND

It is not known, whether outcome reporting in trials of total joint arthroplasty in the recent years is adequate or not. Our objective was to assess whether outcomes reported in total joint replacement (TJR) trials fulfil the Outcome Measures in Rheumatology (OMERACT) Filter 2.0.

METHODS

We systematically reviewed all TJR trials in adults, published in English in 2008 or 2013. Searches were conducted in the Cochrane Central Register of Controlled Trials, MEDLINE, and EMBASE. Two authors independently applied the inclusion criteria for the studies, and any disagreement was resolved with a third review author. All outcome measures were abstracted using a pre-piloted standardised data extraction form and assessed for whether they mapped to one of the three OMERACT Filter 2.0 core areas: pathophysiological, life impact, and death.

RESULTS

From 1635 trials identified, we included 70 trials (30 in 2008 and 40 in 2013) meeting the eligibility criteria. Twenty-two (31%) trials reported the three essential OMERACT core areas. Among the 27 hip replacement surgery trials and 39 knee replacement surgery trials included, 11 hip (41%) and nine knee (23%) trials reported all three essential OMERACT core areas. The most common outcome domains/measures were pain (20/27, 74%) and function (23/27, 85%) in hip trials and pain (26/39, 67%) and function (27/39, 69%) in knee trials. Results were similar for shoulder and hand joint replacement trials.

CONCLUSIONS

We identified significant gaps in the measurement of OMERACT core outcome areas in TJR trials, despite the majority reporting outcome domains of pain and function. An international consensus of key stakeholders is needed to develop a core domain set for reporting of TJR trials.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO CRD42014009216.

Outcome Measures Used in Arthroplasty Trials: Systematic Review of the 2008 and 2013 Literature

OBJECTIVE

Previously published literature assessing the reporting of outcome measures used in joint replacement randomized controlled trials (RCT) has revealed disappointing results. It remains unknown whether international initiatives have led to any improvement in the quality of reporting and/or a reduction in the heterogeneity of outcome measures used. Our objective was to systematically assess and compare primary outcome measures and the risk of bias in joint replacement RCT published in 2008 and 2013.

METHODS

We searched MEDLINE, EMBASE, and CENTRAL for RCT investigating adult patients undergoing joint replacement surgery. Two authors independently identified eligible trials, extracted data, and assessed risk of bias using the Cochrane tool.

RESULTS

Seventy RCT (30 in 2008, 40 in 2013) met the eligibility criteria. There was no significant difference in the number of trials judged to be at low overall risk of bias (n = 6, 20%) in 2008 compared with 2013 [6 (15%); chi-square = 0.302, p = 0.75]. Significantly more trials published in 2008 did not specify a primary outcome measure (n = 25, 83%) compared with 18 trials (45%) in 2013 (chi-square = 10.6316, p = 0.001). When specified, there was significant heterogeneity in the measures used to assess primary outcomes.

CONCLUSION

While less than a quarter of trials published in both 2008 and 2013 were judged to be at low overall risk of bias, significantly more trials published in 2013 specified a primary outcome. Although this might represent a temporal trend toward improvement, the overall frequency of primary outcome reporting and the wide heterogeneity in primary outcomes reported remain suboptimal.

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.