Effect of age on cost-effectiveness of unicompartmental knee arthroplasty compared with total knee arthroplasty in the U.S

Five- and ten-year follow-up of medial unicompartmental knee arthroplasties in obese and non-obese patients

Aims

The aim of this study was to determine whether obesity had a detrimental effect on the long-term performance and survival of medial unicompartmental knee arthroplasties (UKAs).

Methods

This study reviewed prospectively collected functional outcome scores and revision rates of all medial UKA patients with recorded BMI performed in Christchurch, New Zealand, from January 2011 to September 2021. Patient-reported outcome measures (PROMs) were the primary outcome of this study, with all-cause revision rate analyzed as a secondary outcome. PROMs were taken preoperatively, at six months, one year, five years, and ten years postoperatively. There were 873 patients who had functional scores recorded at five years and 164 patients had scores recorded at ten years. Further sub-group analysis was performed based on the patient's BMI. Revision data were available through the New Zealand Joint Registry for 2,323 UKAs performed during this time period.

Results

Obese patients (BMI > 30 kg/m2) were 3.1 years younger than non-obese patients (BMI < 30 kg/m2) at the time of surgery (mean age of obese patients 65.5 years (SD 9.7) and mean age of non-obese patients 68.6 years (SD 10.1)). Preoperatively, obese patients tended to have significantly lower functional scores than non-obese patients, which continued at five and ten years postoperatively. At these timepoints, obese patients had significantly lower scores for most PROMs measured compared to non-obese patients. However, there was no significant difference in the improvement of any of these scores after surgery between obese and non-obese patients. There was no significant difference in revision rates between obese and non-obese patients at any time. All-cause revision rate for obese patients was 0.73 per 100 observed component years compared to 0.67 in non-obese patients at ten years. There was also no significant difference in the aseptic loosening rate between groups.

Conclusion

Our study supports the use of UKAs in obese patients, with similar benefit and survival compared to non-obese patients at ten years.

Does robotic-assisted unicompartmental knee arthroplasty improve alignment and outcomes?

Unicompartmental knee arthroplasty (UKA) continues to increase in popularity as an excellent option for patients with single compartment disease. Robotic-assisted UKA has emerged as an optional tool with hopes for improvement in component placement, limb alignment, and patient outcomes. Furthermore, as patients continue to educate themselves, robotic assistance will become increasingly prevalent. There are now various robotic platforms on the market, each with varying differences, and more published data are emerging on alignment and outcomes. The literature to date largely concludes that robotic-assisted UKA provides more accuracy than manual UKA. Short- to mid-term outcomes may be improved with robotic UKA, but definitive differences in outcomes are uncertain. Survivorship with robotic UKA is non-inferior to reported manual UKA survivorship rates, and more long-term data are needed to fully elucidate this point. Orthopaedic surgeons should weigh these potential advantages against the drawbacks including cost and operative time when making a decision about whether robotic technology is right for their practice.

The Cost-Effectiveness of Computer-Assisted Compared with Conventional Total Knee Arthroplasty: A Payer's Perspective

BACKGROUND

Recent evidence showing that computer-assisted total knee arthroplasty (TKA) is associated with better outcomes compared with conventional TKA for patients with end-stage knee osteoarthritis has not been included in economic evaluations of computer-assisted TKA, which are needed to support coverage decisions. This study evaluated the cost-effectiveness of computer-assisted TKA from a payer's perspective, incorporating recent evidence.

METHODS

We compared computer-assisted TKA with conventional TKA with regard to costs (in 2022 U.S. dollars) and quality-adjusted life-years (QALYs) using Markov models for elderly patients (≥65 years of age) and patients who were not elderly (55 to 64 years of age). Costs and QALYs were estimated in the lifetime for elderly patients and in the short term for patients who were not elderly, under a bundled payment program and a Fee-for-Service program. Transition probabilities, costs, and QALYs were retrieved from the literature, a national knee arthroplasty registry, and the National Center for Health Statistics. Threshold and probabilistic sensitivity analyses were conducted to examine the robustness of key estimates used in the base-case analysis. Using projected estimates of TKA utilization, the total cost savings of performing computer-assisted TKA rather than conventional TKA were estimated.

RESULTS

Compared with conventional TKA, computer-assisted TKA was associated with higher QALYs and lower costs for both elderly patients and patients who were not elderly, regardless of payment programs, making computer-assisted TKA a favorable treatment option. Widespread adoption of computer-assisted TKA in all U.S. patients would result in an estimated total cost saving of $1 billion for payers.

CONCLUSIONS

Compared with conventional TKA, computer-assisted TKA reduces costs to payers while providing favorable outcomes. Payers may consider providing additional payment incentives to providers for performing computer-assisted TKA, to achieve outcome improvement and cost control by facilitating widespread adoption of computer-assisted TKA.

LEVEL OF EVIDENCE

Economic and Decision Analysis Level II . See Instructions for Authors for a complete description of levels of evidence.

The Relationship Between Age and 30-Day Outcomes Following Unicompartmental Versus Total Knee Arthroplasty

BACKGROUND

Understanding the short-term complication profile following unicompartmental knee arthroplasty (UKA) versus total knee arthroplasty (TKA) can improve surgical decision-making and patient outcomes. This study aimed to determine if the difference in risk of 30-day morbidity and mortality between UKA and TKA varied based on patient age.

METHODS

This retrospective study of a national quality improvement database using data from 2014 to 2020 included 403,342 patients undergoing UKA (n = 12,324) or TKA (n = 391,018). A generalized additive model evaluated nonlinear relationships between primary outcome and predictors (age, procedure, and procedure × age interaction) using a 1:5 UKA to TKA matched sample. Probabilities and odds ratios (95% confidence interval [CI]) estimated the relative risk of complications by age.

RESULTS

In the generalized additive model, TKA patients relative to UKA had 1.30 odds (95% CI 1.19 to 1.43, P < 0.001) of 30-day morbidity and mortality. There was a significant nonlinear relationship between age and primary outcome (P = 0.02), such that the odds were lowest at younger ages. They increased slowly until the age of 65 years, when the slope became steeper. The interaction terms for age and procedure were not significant (P = 0.30). The 30-day probability for short-term complications of a 65-, 75-, and 85-year-olds undergoing UKA was 2.1% (95% CI 1.8 to 2.3), 2.4% (95% CI 2.0 to 2.8), and 3.2% (95% CI 2.3 to 4.1), respectively. The probability of a 65-, 75-, and 85-year-old undergoing TKA was 2.9% (95% CI 2.7 to 3.0), 3.6% (95% CI 3.3 to 3.8), and 5.5% (95% CI 4.7 to 6.3), respectively.

CONCLUSIONS

Patients undergoing UKA had a quantifiable lower likelihood of morbidity or mortality than TKA at all ages. These data can provide individualized risk for UKA and TKA across the age spectrum and could be helpful in counseling patients regarding their perioperative risk.

LEVEL OF EVIDENCE

III (retrospective comparative study).

Outcomes of fixed versus mobile-bearing medial unicompartmental knee arthroplasty

Aims

The optimal bearing surface design for medial unicompartmental knee arthroplasty (UKA) remains controversial. The aim of this study was to compare outcomes of fixed-bearing (FB) and mobile-bearing (MB) UKAs from a single high-volume institution.

Methods

Prospectively collected data were reviewed for all primary cemented medial UKAs performed by seven surgeons from January 2006 to December 2022. A total of 2,999 UKAs were identified, including 2,315 FB and 684 MB cases. The primary outcome measure was implant survival. Secondary outcomes included 90-day and cumulative complications, reoperations, component revisions, conversion arthroplasties, range of motion, and patient-reported outcome measures. Overall mean age at surgery was 65.7 years (32.9 to 94.3), 53.1% (1,593/2,999) of UKAs were implanted in female patients, and demographics between groups were similar (p > 0.05). The mean follow-up for all UKAs was 3.7 years (0.0 to 15.6).

Results

Using revision for any reason as an endpoint, five-year survival for FB UKAs was 97.2% (95% CI 96.4 to 98.1) compared to 96.0% for MB (95% CI 94.1 to 97.9; p = 0.008). The FB group experienced fewer component revisions (14/2,315, 0.6% vs 12/684, 1.8%; p < 0.001) and conversion arthroplasties (38/2315, 1.6% vs 24/684, 3.5%; p < 0.001). A greater number of MB UKAs underwent revision due to osteoarthritis progression (FB = 21/2,315, 0.9% vs MB = 16/684, 2.3%; p = 0.003). In the MB group, 12 (1.8%) subjects experienced bearing dislocations which required revision surgery. There were 15 early periprosthetic tibia fractures (0.6%) in the FB group compared to 0 for MB (p = 0.035).

Conclusion

In similar patient populations, FB UKAs demonstrated slightly higher survival than a commonly used MB design. Adverse event profiles differed by bearing type, with an increased risk of bearing dislocation and OA progression with MB designs, and early periprosthetic tibia fractures for FB designs.

Revision Anterior Cruciate Ligament Reconstruction and Medial Unicompartmental Knee Replacement

Introduction

Failure of anterior cruciate ligament (ACL) reconstructive surgery often presents alongside progressive mono-compartment tibiofemoral arthritis. Total knee arthroplasty (TKA) is the conventional treatment option for this scenario but is associated with high levels of dissatisfaction amongst this younger cohort.

Case Report

This case report outlines a 39-year-old male patient, who underwent revision ACL reconstruction plus a medial unicompartmental knee arthroplasty (UKA) replacement as a single-stage procedure.

Conclusion

This is the first reported ACL revision with a simultaneous medial UKA and provides an alternative solution to a TKA in this younger cohort of patients.

[Evolving indications for partial knee replacement : New aspects]

BACKGROUND

Partial knee replacement has proven to be an effective therapy for advanced unicompartmental arthrosis of the knee. Despite continuous advancements in implants and surgical techniques over the past decades, the global preference for total knee arthroplasty still persists for historical reasons.

OBJECTIVES

This report aims to illuminate advantages and disadvantages of partial knee replacement considering long-term results, the evolution of indication criteria over recent decades and new aspects in patient selection with potential improvements through emerging technologies.

MATERIAL AND METHODS

The analysis involves the examination of long-term results from clinical studies and registry data, highlighting the risk factors for potential failures and their influence on the development of indication criteria.

RESULTS

Present-day long-term results demonstrate excellent prosthetic survival, aligning with outcomes from total knee arthroplasty. New perspectives for expanding indication criteria are discussed, including the possible application of partial knee replacement in cases of severe varus deformity > 15°, anterior cruciate ligament insufficiency, young active patients, anterior knee pain, and/or patellofemoral arthritis, as well as mild radiographic arthritis with degenerative medial meniscus root tear and meniscal extrusion.

DISCUSSION

Indication criteria have consistently expanded in recent years, taking into account modern insights, and the application of advanced technologies can enhance precision and minimize surgical errors. Furthermore, this report emphasizes that revision rates are not the sole criterion for success and underscores the necessity for a comprehensive examination of clinical results.

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.

A systematic review of cartilage procedures for unstable osteochondritis dissecans

OBJECTIVES

Osteochondritis dissecans can result in significant limitations in activity, pain, and early osteoarthritis. There are various treatment modalities to address these defects. The purpose of this study was to provide a qualitative summary of the various treatment options for unstable osteochondritis dissecans in the knee.

METHODS

A literature search was performed on osteochondritis dissecans in the knee using PubMed (MEDLINE), Embase, and Cochrane electronic databases. The search was completed using a combination of the following terms: 'osteochondritis dissecans,' 'OCD,' 'osteochondral,' 'articular cartilage,' 'repair,' 'surgery,' 'treatment,' 'osteochondral allograft,' 'autologous chondrocyte implantation,' 'unstable,' 'knee,' 'clinical studies.'

RESULTS

A total of 682 studies were found, of which 24 were included in the qualitative analysis. The quality score ranged from 46 to 80, and the mean follow-up ranged from 2 to 17 years. The most common surgical procedures were internal fixation (n = 7 studies), ACI (n = 6), fragment excision (n = 3), MACI (n = 2), bone graft + ACI (n = 2), OCA (n = 2), mosaicplasty/OAT (n = 2), and scaffold (n = 2). Overall, the reported outcome measures were heterogeneous in nature. Post-operative International Knee Documentations Committee (IKDC) scores ranged from 75 to 85 and Lysholm scores ranged from 70 to 93.5. Tegner scores ranged from 4 to 5. Rates of failure, complication, and revision were highly variable across studies and surgical techniques.

CONCLUSION

There are a variety of surgical options for the treatment of unstable osteochondritis dissecans. In skeletally immature patients, internal fixation demonstrated acceptable rates of radiographic union and patient reported outcome measures. In skeletally mature patients with large lesions, MACI and OCA transplantation provided similar patient reported outcomes.

The Impact of Arthroscopy on Surgical Decision-Making and Outcomes in Osteoarthritis Patients Undergoing Unicompartmental Knee Arthroplasty

Background and objective Although unicompartmental knee arthroplasty (UKA) is a minimally invasive procedure, its application is limited due to strict criteria related to indications. In clinical practice, the aid of procedures such as arthroscopy is occasionally required to determine the surgical indication and thereby improve prognosis. In light of this, this study aimed to evaluate the impact of intraoperative arthroscopy on surgical decision-making in osteoarthritis (OA) patients and the prognosis of patients undergoing UKA. Methodology The clinical records of patients diagnosed with knee OA who underwent knee arthroplasty between January 2017 and January 2020 were retrospectively analyzed. The inclusion criteria were as follows: patients with radiographic evidence of single-compartmental Kellgren-Lawrence (KL) grade 3 or 4 knee OA but presenting symptoms of persistent multicompartmental knee pain or locking for at least six months, with a history of anterior cruciate ligament (ACL) injury or meniscus tear. They had undergone either UKA or total knee arthroplasty (TKA). Data on clinical characteristics and outcomes at baseline and during follow-up were collected. Results A total of 429 patients were included in the study. Patients who underwent arthroscopy were more likely to undergo UKA surgery than those who did not (p<0.05). Among patients who underwent UKA, no instances of blood transfusion during hospitalization or postoperative complications were reported, regardless of whether arthroscopy was performed or not. Although the overall Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) scores and Knee Society Functional Score (KSFS) did not differ between the two groups, the Knee Society Score (KSS) was significantly higher in patients who underwent arthroscopy (88.77 ±5.09) compared to those who did not (85.53 ±5.11). Similarly, the arthroscopy group had a higher overall Forgotten Joint Score (FJS) (44.6 ±4.20) than the UKA-only group (42.05 ±3.58). Conclusion Arthroscopy findings can assist in surgical decision-making for OA patients. Performing arthroscopy and UKA simultaneously is relatively safe and may be associated with favorable outcomes.

An ACS-NSQIP Analysis of Unicompartmental Knee Arthroplasty Trends from 2013 to 2018

Unicompartmental knee arthroplasty (UKA) volume has increased with advances in implant design, perioperative protocols, and patient selection. This study analyzed national trends of UKA from 2013 to 2018 and the relationship between patient demographics and postoperative outcomes. Data on UKA (CPT 27446) from 2013 to 2018 was collected from the National Surgical Quality Improvement Program (NSQIP). Variables collected included patient demographics, American Society of Anesthesiology classification, functional status, NSQIP morbidity probability, operative time, length of stay, 30-day reoperation, and readmission rates. There was an increase in outpatient UKAs performed (920 in 2013; 11,080 in 2018) (p < 0.0001). Analysis of variance from 2013 to 2018 revealed significant decrease in patient body mass index (BMI) (32.5 in 2013; 31.5 in 2018) (p < 0.01) and NSQIP morbidity probability (0.014 in 2013; 0.011 in 2018) (p < 0.0001). Operative time increased (79.1 minutes in 2013; 84.4 minutes in 2018) (p < 0.01), but length of stay decreased (0.9 days in 2013; 0.5 days in 2018) (p < 0.0001). The number of all-cause and related readmissions decreased significantly (p < 0.045; p < 0.01). Age, male gender, BMI >40 and chronic obstructive pulmonary disease (COPD) were significant predictors for 30-day readmission. BMI >40 was a significant predictor for discharge destination. UKA has seen a rise in incidence from 2013 to 2018 with an increasing number of outpatient UKAs. Operative times and 30-day readmissions have both decreased in this time. BMI > 40 is predictive for discharge destination after UKA, while age, male gender, BMI >40, and COPD are independent risk factors for 30-day readmission.

Occupational Outcomes and Revision Rates for Medial Unicondylar Knee Arthroplasty in U.S. Military Servicemembers

This study evaluates return to work and revision rates for medial unicondylar knee arthroplasty (UKA) in a high-demand military cohort. Patient demographic and clinical variables were isolated from the medical records of active-duty military servicemembers with at least 2 years of postoperative follow-up and correlated with return to work, medial UKA survivorship, and perioperative complications. The medial UKA annual revision rate was calculated as the percentage of implants revised per observed component year. A total of 39 servicemembers underwent 46 primary medial UKAs (32 unilateral and 7 bilateral) with a mean follow-up of 3.9 (2.0-6.6) years. At a minimum of 2 years postoperatively, 33 (85%) servicemembers returned to military service or successfully completed their service obligation. Older servicemembers (odds ratio [OR] = 0.67; 95% confidence interval [CI]: 0.45, 0.99) had a significantly decreased OR for knee-related medical separation. Nine servicemembers (20%) had conversion to TKA at an average of 2.4 (range, 0.6-5.6) years with a medial UKA annual revision rate of 5%. When compared with Navy/Air Force, Army/Marine servicemembers had an increased TKA conversion rate (OR = 5.40; 95% CI: 1.13, 25.81). Older age decreased the likelihood of medical separation and Army/Marines service was the sole risk factor associated with conversion to TKA. The level of evidence is IV, therapeutic case series.

No Difference in Quality-Of-Life Outcomes in the First 7 Years Following Primary Total Knee Arthroplasty Performed Using Computer Navigation Versus Conventional Referencing: A Propensity Score-Matched Analysis

BACKGROUND

Computer navigation techniques can potentially improve both the accuracy and precision of prosthesis implantation in total knee arthroplasty (TKA) but its impact on quality-of-life outcomes following surgery remains unestablished.

METHODS

An institutional arthroplasty registry was queried to identify patients with TKA performed between January 1, 2007 and December 31, 2019. Propensity score matching based on demographical, medical, and surgical variables was used to match computer-navigated to conventionally referenced cases. The primary outcomes were Veterans RAND 12 Item Health Survey scores (VR-12 PCS and MCS), Short Form 6 Dimension utility values (SF-6D), and quality-adjusted life years (QALYs) in the first 7 years following surgery.

RESULTS

A total of 629 computer-navigated TKAs were successfully matched to 1,351 conventional TKAs. The VR-12 PCS improved by a mean of 12.75 and 11.94 points in computer-navigated and conventional cases at 12-month follow-up (P = .25) and the VR-12 MCS by 6.91 and 5.93 points (P = .25), respectively. The mean VR-12 PCS improvement at 7-year follow-up (34.4% of the original matched cohort) for navigated and conventional cases was 13.00 and 12.92 points (P = .96) and for the VR-12 MCS was 4.83 and 6.30 points (P = .47), respectively. The mean improvement in the SF-6D utility score was 0.164 and 0.149 points at 12 months (P = .11) and at 7 years was 0.115 and 0.123 points (P = .69), respectively. Computer-navigated cases accumulated 0.809 QALYs in the first 7 years, compared to 0.875 QALYs in conventionally referenced cases (P = .65). There were no differences in these outcomes among a subgroup analysis of obese patients (body mass index ≥ 30 kg/m²).

CONCLUSION

The use of computer navigation did not provide an incremental benefit to quality-of-life outcomes at a mean of 2.9 years following primary TKA performed for osteoarthritis when compared to conventional referencing techniques.

Understanding Health Economics in Joint Replacement Surgery

The number of arthroplasty procedures has been rising at a significant rate, contributing to a notable portion of the nation's health care spending. This growth has contributed to an increase in the number of health care economic studies in the field of adult reconstruction surgery. Although these articles are filled with important information, they can be difficult to understand without a background in business or economics. The goal of this review is to define the common terminology used in health care economic studies, assess their value and benefit in the context of total joint arthroplasty, and highlight shortcomings in the current literature. [Orthopedics. 2022;45(4):e174-e182.].

Unicompartmental Knee Arthroplasty in Octogenarians: A National Database Analysis Including Over 700 Octogenarians

Background

Unicompartmental knee arthroplasty (UKA) may be considered for select patients to relieve pain and restore function of the knee joint. Little research to date has explored the complication profile of UKA in an older population. The current study uses a large national surgical database to examine the 30-day postoperative adverse events in octogenarians compared with those in nonoctogenarians.

Material and methods

The 2012-2018 National Surgical Quality Improvement Program database was queried for all patients undergoing UKA for osteoarthritis. Those patients aged 80 years or older composed the octogenarian age group. Demographics and medical comorbidities were cataloged, in addition to 30-day adverse events. Multivariate regression analysis controlled for differences in demographics and comorbidities. Significance was set at P < .05.

Results

A total of 10,103 patients undergoing UKA were identified, of which 728 (7.2%) were octogenarians. The octogenarian cohort had significantly higher comorbidity burden than nonoctogenarians. After controlling for demographics other than age, American Society of Anesthesiologists score, and medical comorbidities, octogenarians had higher 30-day odds of death (odds ratio [OR] = 6.12, P = .024), minor adverse events (OR = 2.97, P = .001), prolonged hospital length of stay (OR = 2.30, <0.001), nonhome discharge (OR = 4.50, P < .001), and readmission (OR = 1.72, P = .015), but did not experience increased odds of serious adverse events (OR = 1.07, P = .172) or return to the operating room (OR = 0.97, P = .881).

Conclusion

The present study found a statistically significant increase in several adverse events within 30 days of surgery for patients aged ≥80 years when compared with patients younger than 80 years. Namely, UKA in octogenarians was associated with significantly increased odds of short-term mortality, urinary tract infection, transfusion, prolonged hospital stay, and readmission.

Differences in Clinical and Functional Outcomes Between Osteochondral Allograft Transplantation and Autologous Chondrocyte Implantation for the Treatment of Focal Articular Cartilage Defects

Background:

Articular cartilage pathology can result from a spectrum of origins, including trauma, osteochondritis dissecans, avascular necrosis, or degenerative joint disease.

Purpose:

To compare the differences in clinical and patient-reported outcomes after autologous chondrocyte implantation (ACI) versus osteochondral allograft transplantation (OCA) in patients with focal articular cartilage defects without underlying bone loss.

Study Design:

Cohort study; Level of evidence, 3.

Methods:

A retrospective review identified patients who underwent ACI or OCA between 2008 and 2016 for isolated grades 3 and 4 articular cartilage defects without underlying bone loss. Outcome measures included the Knee injury and Osteoarthritis Outcome Score for Joint Replacement (KOOS JR), International Knee Documentation Committee (IKDC) evaluation, and 12-Item Short Form Health Survey–Physical Component (SF-12-P) scores. Defect location, size, complications, and rate of subsequent surgery were determined.

Results:

Overall, 148 patients were included: 82 (55%) underwent ACI and 66 (45%) underwent OCA. The mean age at the time of surgery was 31.2 years within the ACI cohort and 37.7 years within the OCA cohort (P < .001); the mean follow-up for both cohorts was 6.7 years (P = .902). Within the ACI group, 28 (34%) patients had multifocal defects, 21 (26%) had defects confined to the femoral condyles, and 33 (40%) had defects in the patellofemoral region. Within the OCA group, 23 (35%) patients had multifocal defects, 30 (46%) had confined femoral condyle lesions, and 13 (20%) had patellofemoral defects. When comparing by lesion location, there were no significant differences in KOOS JR, and IKDC scores between the ACI and OCA cohorts (P < .05). There was, however, a significant difference for SF-12-P scores for FDD trochlear lesions. In both cohorts, traumatic patellofemoral pathology demonstrated lower patient-reported outcomes and higher failure rates than degenerative lesions. The overall rate of failure, defined as graft failure with revision surgery and/or conversion to arthroplasty, was significantly greater in the OCA group (21% vs 4%; P = .002).

Conclusion:

Study results indicated that ACI provides similar outcomes to OCA with or without concomitant procedures for the treatment of symptomatic articular cartilage defects in all lesion locations and may have a lower revision rate for multifocal and condylar lesions.

Results of Simultaneous Unicompartmental Knee Arthroplasty and Anterior Cruciate Ligament Reconstruction: A Systematic Review

This systematic review aimed to investigate the clinical and functional outcomes and complication rate of simultaneous anterior cruciate ligament reconstruction (ACLR) and unicompartmental knee arthroplasty (UKA). A systematic search in PubMed-Medline, Cochrane Library, and Google Scholar was carried out to identify eligible randomized clinical trials, observational studies, or case series that reported on clinical and functional results of combined ACLR and UKA in adults with a unicompartmental knee osteoarthritis and ACL deficiency. Four retrospective studies and three prospective studies were included in this review. A total of 169 patients were included with a mean follow-up of 6.3 years. The Mean Oxford Knee Score improved from 29.4 to 43.9 at the final follow-up. All the other reported scores significantly improved after surgery. The overall revision rate was 3.5%. The MINORS score ranged from 8 to 14. Association analysis of MINORS score and year of publication, through Pearson's coefficient, showed no significant association (p = -0.089). Simultaneous ACLR and UKA is a safe procedure with a significant postoperative improvement of functional and clinical outcomes for patients with ACL injury that complain of knee instability and isolated medial compartment pain.

Unicompartmental Knee Arthroplasty: Survivorship and Risk Factors for Revision: A Population-Based Cohort Study with Minimum 10-Year Follow-up

BACKGROUND

Operative management for end-stage knee osteoarthritis (OA) primarily consists of arthroplasty. Total knee arthroplasty (TKA) is the so-called gold standard for multicompartmental OA. In selected patients, specifically those with unicompartmental OA and no definite contraindications, realignment osteotomies and unicompartmental knee arthroplasty (UKA) are viable options. UKA offers several advantages over TKA, including preservation of both cruciate ligaments, faster recovery, and less osseous resection. The purpose of this study was to determine the survivorship of UKAs and risk factors for all-cause revision surgery in patients with a minimum follow-up of 10 years in a large population-based database.

METHODS

We performed a population-based cohort study using linked administrative databases in Ontario, Canada. We identified all UKAs performed from January 2002 through December 2006. All patients had a minimum 10-year follow-up. Demographic data and outcomes were summarized using descriptive statistics. We used a Cox proportional hazards model with the Fine and Gray method accounting for competing risks such as death to analyze the effect of surgical and patient factors on the risk of revision of UKA.

RESULTS

A total of 4,385 patients were identified as having undergone primary UKA from 2002 through 2006 in Ontario. Of these patients, 779 underwent revision surgery, for a cumulative risk for all-cause revision of 16.5% at 10 years (95% confidence interval [CI]: 15.4% to 17.7%). Mechanical loosening was the reason for 83.4% of all revisions. Male sex, diabetes, an age younger than 50 years, and cementless implants were significant risk factors for revision surgery. Residence in a rural or urban setting, income quintile, discharge destination, and type of OA were not associated with the risk of revision. Survivorship at 1, 5, 10, and 15 years was 97.2%, 90.5%, 83.5%, and 81.9%, respectively.

CONCLUSIONS

This study demonstrated a >80% long-term survivorship for UKA based on a large administrative database sample and identified important risk factors for failure including male sex, younger age, diabetes, and cementless fixation. This study found rates of survivorship similar to those previously reported in the literature, while identifying key risk factors for failure. Patient selection has always been identified as a key factor in ensuring successful UKA, and the risk factors identified in this study may help guide decision-making for surgeons and patients dealing with unicompartmental knee OA.

LEVEL OF EVIDENCE

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

Costs of unicompartmental compared with total knee arthroplasty : a matched cohort study over ten years

AIMS

The aim of this study was to compare ten-year longitudinal healthcare costs and revision rates for patients undergoing unicompartmental knee arthroplasty (UKA) and total knee arthroplasty (TKA).

METHODS

The Humana database was used to compare 2,383 patients undergoing UKA between 2007 and 2009, who were matched 1:1 from a cohort of 63,036 patients undergoing primary TKA based on age, sex, and Elixhauser Comorbidity Index. Medical and surgical complications were tracked longitudinally for one year following surgery. Rates of revision surgery and cumulative mean healthcare costs were recorded for this period of time and compared between the cohorts.

RESULTS

Patients undergoing TKA had significantly higher rates of manipulation under anaesthesia (3.9% vs 0.9%; p < 0.001), deep vein thrombosis (5.0% vs 3.1%; p < 0.001), pulmonary embolism (1.5% vs 0.8%; p = 0.001), and renal failure (4.2% vs 2.2%; p < 0.001). Revision rates, however, were significantly higher for UKA at five years (6.0% vs 4.2%; p = 0.007) and ten years postoperatively (6.5% vs 4.4%; p = 0.002). Longitudinal-related healthcare costs for patients undergoing TKA were greater than for those undergoing UKA at one year ($24,771 vs $22,071; p < 0.001) and five years following surgery ($26,549 vs $25,730; p < 0.001); however, the mean costs of TKA were comparable to UKA at ten years ($26,877 vs $26,891; p = 0.425).

CONCLUSION

Despite higher revision rates, patients undergoing UKA had lower mean healthcare costs than those undergoing TKA up to ten years following the procedure, at which time costs were comparable. In the era of value-based care, surgeons and policymakers should be aware of the costs involved with these procedures. UKA was associated with fewer complications at one year postoperatively but higher revision rates at five and ten years. While UKA was significantly less costly than TKA at one and five years, costs at ten years were comparable with a mean difference of only $14. Lowering the risk of revision surgery should be targeted as a source of cost savings for both UKA and TKA as the mean related healthcare costs were 2.5-fold higher in patients requiring revision surgery. Cite this article: Bone Joint J 2021;103-B(6 Supple A):23-31.

[Recommendations for unicondylar knee replacement in the course of time : A current inventory]

BACKGROUND

A higher patient satisfaction stands in contrast to higher revision rates of unicondylar knee joint endoprosthetics (UKE) compared to total knee joint endoprosthetics (TKE). Furthermore, old "dogmas" regarding indications and contraindications persist, which is still reflected in the significantly different case numbers.

AIM

The aim of this article is to provide an overview of the current literature regarding 1. indication and contraindication (BMI, age, sport, arthrosis of other compartments, ligament status) and 2. the "eternal rival" fixed or mobile bearing for UKE.

RESULTS

The choice of the right patient remains essential, even if all the old "dogmas" of contraindications have been relativized or even outdated. Arthroses of the contralateral (in medial UKE correspondingly lateral) compartment and advanced arthroses of the lateral patella facet remain the only persistent contraindications. In contrast, a high BMI, age, chondrocalcinosis, medial patella facet and a defective (but particularly functionally stable) ACL are not contraindications; however, severe obesity is responsible for a significantly higher complication rate and probably a higher rate of loosening. Rather, the experience and thus the number of UKEs of the individual surgeon is decisive for the outcome, to which the discussion about mobile or fixed inlays must also be completely subordinated.

CONCLUSION

The indications for UKE can, therefore, be extended with a clear conscience on the basis of literature, and the current 1:10 UKE:TKE ratio in Germany can be shifted significantly.

The effect of a micro-visual intervention on the accelerated recovery of patients with kinesiophobia after total knee replacement during neo-coronary pneumonia

BACKGROUND

The global neo-coronary pneumonia epidemic has increased the workload of healthcare institutions in various countries and directly affected the physical and psychological recovery of the vast majority of patients requiring hospitalization in China. We anticipate that post-total knee arthroplasty kinesiophobia may have an impact on patients' postoperative pain scores, knee function, and ability to care for themselves in daily life. The purpose of this study is to conduct a micro-video intervention via WeChat to verify the impact of this method on the rapid recovery of patients with kinesiophobia after total knee arthroplasty during neo-coronary pneumonia.

METHODS

Using convenience sampling method, 78 patients with kinesiophobia after artificial total knee arthroplasty who met the exclusion criteria were selected and randomly grouped, with the control group receiving routine off-line instruction and the intervention group receiving micro-video intervention, and the changes in the relevant indexes of the two groups of patients at different time points on postoperative day 1, 3 and 7 were recorded and analyzed.

RESULTS

There were no statistical differences in the scores of kinesiophobia, pain, knee flexion mobility (ROM) and ability to take care of daily life between the two groups on the first postoperative day (P > .05). On postoperative day 3 and 7, there were statistical differences in Tampa Scale for kinesiophobia, pain, activities of daily living scale score and ROM between the two groups (P < .01), and the first time of getting out of bed between the two groups (P < .05), and by repeated-measures ANOVA, there were statistically significant time points, groups and interaction effects of the outcome indicators between the 2 groups (P < .01), indicating that the intervention group reconstructed the patients' postoperative kinesiophobiaand hyperactivity. The level of pain awareness facilitates the patient's acquisition of the correct functional exercises to make them change their misbehavior.

CONCLUSIONS

WeChat micro-video can reduce the fear of movement score and pain score in patients with kinesiophobia after unilateral total knee arthroplasty, shorten the first time out of bed, and improve their joint mobility and daily living ability.

ETHICS

This study has passed the ethical review of the hospital where it was conducted and has been filed, Ethics Approval Number: 20181203-01.

Patient Preferences for Surgical Treatment of Knee Osteoarthritis: A Discrete-Choice Experiment Evaluating Total and Unicompartmental Knee Arthroplasty

BACKGROUND

Total knee arthroplasty (TKA) is a common treatment for end-stage knee osteoarthritis but is associated with increased complication rates compared with unicompartmental knee arthroplasty (UKA). UKA offers better functional outcomes but is associated with a higher risk of revision. The purpose of this study was to apply good-practice, stated-preference methods to quantify patient preferences for benefit-risk tradeoffs associated with arthroplasty treatments for end-stage knee osteoarthritis.

METHODS

A discrete-choice experiment was developed with the following attributes: chance of complications, functional ability, awareness of the knee implant, and chance of needing another operation within 10 years. Patients included those aged 40 to 80 years with knee osteoarthritis. A pivot design filtered respondents into 1 of 2 surveys on the basis of self-reported functional ability (good compared with fair or poor) as measured by the Oxford Knee Score. Treatment-preference data were collected, and relative attribute-importance weights were estimated.

RESULTS

Two hundred and fifty-eight completed survey instruments from 92 males and 164 females were analyzed, with 72 respondents in the good-function cohort and 186 in the fair/poor-function cohort. Patients placed the greatest value or relative importance on serious complications and rates of revision in both cohorts. Preference weights did not vary between cohorts for any attribute. In the good-function cohort, 42% of respondents chose TKA and 58% chose UKA. In the fair/poor-function cohort, 54% chose TKA and 46% chose UKA.

CONCLUSIONS

Patient preferences for various treatment attributes varied among patients in a knee osteoarthritis population. Complication and revision rates were the most important factors to patients, suggesting that physicians should focus on these areas when discussing treatments. The proportion of patients who chose UKA suggests that the current trend of increased UKA utilization is aligned with patient preferences.

CLINICAL RELEVANCE

Systematic elicitation of patient preferences for knee arthroplasty procedures, which lays out evidence-based risks and benefits of different treatments, indicates a larger subset of the knee osteoarthritis population may prefer UKA than would be suggested by the current rates of utilization of the procedure. Arthroplasty treatment should align with patient preferences and eligibility criteria to better deliver patient-centered care.

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.

Unicompartmental Knee Replacement Combined to Anterior Cruciate Ligament Reconstruction: Midterm Results

A study was conducted to retrospectively evaluate the outcomes of combined medial unicompartmental knee replacement (UKR) and anterior cruciate ligament (ACL) reconstruction. The hypothesis was that this procedure would lead to satisfying results in patients affected by medial osteoarthritis and ACL insufficiency. Fourteen patients with ACL deficiency and concomitant medial compartment symptomatic osteoarthritis were treated from 2006 to 2010. Twelve of them were followed-up for an average time of 7.8 year (range: 6-10 years). Assessment included Knee Osteoarthritis Outcome score (KOOS), Oxford Knee score (OKS), American Knee Society scores (AKSS), Western Ontario and McMaster (WOMAC) index of osteoarthritis, Tegner's activity level, objective examination including instrumented laxity test with KT-1000 arthrometer, and standard X-rays. KOOS score, OKS, WOMAC index, and the AKSS improved significantly at follow-up (p < 0.001). There was no clinical evidence of instability in any of the knees as evaluated with clinical and instrumented laxity testing (p < 0.001). No pathologic radiolucent lines were observed around the components. In one patient, a total knee prosthesis was implanted due to the progression of signs of osteoarthritis in the lateral compartment 3 years after primary surgery. UKR combined with ACL reconstruction is an effective therapeutic option for the treatment of combined medial unicompartmental knee osteoarthritis and ACL deficiency and confirms subjective and objective clinical improvement up to 8 years after surgery. This study reflects level IV evidence.

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.

Analysis of the following Related Surgeries of Unicompartmental Knee Arthroplasty and Total Knee Arthroplasty: A Taiwanese National Health Insurance Research Database Population-Based Study

Background

Current treatment options for both unicompartmental knee arthroplasty (UKA) and total knee arthroplasty (TKA) are still controversial with no consistent results in which one is superior to others. This is the first study to examine and analyze the following related data available in patients receiving either UKA or TKA from the National Health Research Database (NHIRD) in Taiwan.

Methods

The database was searched from NHIRD, pooling one million random patients. Patients' age, gender, and comorbidities were analyzed in either UKA or TKA between January 2005 and December 2013, or up until death. For the patients that had received bilateral surgeries, further subgrouping was divided into TKA to TKA, UKA to UKA, TKA to UKA, and UKA to TKA to analyze the completion rate curve. Additional analysis of the order codes 64202B, 64053B, and 64198B was defined as failures, and the related failure rate curves were analyzed separately within ten years. Finally, infection-related codes were analyzed.

Results

6,179 patients (n = 276 UKA; n = 5903 TKA) were selected. Age (p < 0.0001) and gender (p = 0.037) had significant differences, with more young population and males having UKA than TKA. Most comorbidities had no significant difference. For the bilateral surgery analysis, the UKA to UKA group had the fastest completion rate (p < 0.001) and UKA to TKA was the slowest. There were no significant differences in the failure rates of 64202B, 64053B, and 64198B.

Conclusion

Most UKA and TKA are appropriate solutions to treat patients with osteoarthritis or osteonecrosis. UKA to UKA is the quickest bilateral completion surgery, and UKA has a higher chance of undergoing revision surgery than TKA.

Unicompartmental knee arthroplasty, an enigma, and the ten enigmas of medial UKA

Unicompartmental knee arthroplasty (UKA) is a bone- and ligament-sparing alternative to total knee arthroplasty in the patients with end-stage single-compartment degeneration of the knee. Despite being a successful procedure, the multiple advantages of UKA do not correlate with its usage, most likely due to the concerns regarding prosthesis survivability, patient selection, ideal bearing design, and judicious use of advanced technology among many others. Therefore, the purpose of this study is to review and summarize the debated literature and discuss the controversies as “Ten Enigmas of UKA.”

Systematic Review of the Evolution of Health-Economic Evaluation Models of Osteoarthritis

OBJECTIVE

To comprehensively synthesize the evolution of health-economic evaluation models (HEEMs) of all osteoarthritis (OA) interventions, including preventions, core treatments, adjunct nonpharmacologic interventions, pharmacologic interventions, and surgical treatments.

METHODS

The literature was searched within health-economic/biomedical databases. Data extracted included OA type, population characteristics, model setting/type/events, study perspective, and comparators; the reporting quality of the studies was also assessed. The review protocol was registered at the International Prospective Register of Systematic Reviews (CRD42018092937).

RESULTS

Eighty-eight studies were included. Pharmacologic and surgical interventions were the focus in 51% and 44% of studies, respectively. Twenty-four studies adopted a societal perspective (with increasing popularity after 2013), but most (63%) did not include indirect costs. Quality-adjusted life years was the most popular outcome measure since 2008. Markov models were used by 62% of studies, with increasing popularity since 2008. Until 2010, most studies used short-to-medium time horizons; subsequently, a lifetime horizon became popular. A total of 86% of studies reported discount rates (predominantly between 3% and 5%). Studies published after 2002 had a better coverage of OA-related adverse events (AEs). Reporting quality significantly improved after 2001.

CONCLUSION

OA HEEMs have evolved and improved substantially over time, with the focus shifting from short-to-medium-term pharmacologic decision-tree models to surgical-focused lifetime Markov models. Indirect costs of OA are frequently not considered, despite using a societal perspective. There was a lack of reporting sensitivity of model outcome to input parameters, including discount rate, OA definition, and population parameters. While the coverage of OA-related AEs has improved over time, it is still not comprehensive.

Does Patellofemoral Disease Affect Outcomes in Contemporary Medial Fixed-Bearing Unicompartmental Knee Arthroplasty?

BACKGROUND

Pre-existing patellofemoral disease has traditionally been a contraindication to unicompartmental knee arthroplasty (UKA), as proposed by Kozinn and Scott. More recently, some propose that patellofemoral disease can be ignored in UKA; however, the supporting research is predominantly in mobile-bearing designs. The study purpose was to evaluate the effect of patellofemoral disease osteoarthritis severity on latest outcomes after fixed-bearing medial UKA.

METHODS

A retrospective review of 147 consecutive medial fixed-bearing UKAs with minimum 1-year follow-up was performed. The medial and lateral patellofemoral compartments were graded according to the Kellgren & Lawrence grading system, Osteoarthritis Research Society International atlas, and intraoperative assessment performed using the Outerbridge classification. Prospectively collected University of California Los Angeles Activity Level, modern Knee Society pain and function scores, and Likert scale satisfaction were correlated with presence and severity of pre-existing patellofemoral disease.

RESULTS

One hundred forty-three medial UKAs were analyzed with mean age, body mass index, and follow-up of 64.1 years, 30.7 kg/m², and 24.0 months, respectively. No correlations were observed between patellofemoral disease severity and patient-reported outcome measures at latest follow-up or improvement scores for Kellgren & Lawrence grading system or Osteoarthritis Research Society International atlas (P ≥ .058). Improvement in activity level scores was significantly higher for patients with less patellar and trochlear chondral damage despite not reaching minimal clinically important difference of 2.0 (P ≤ .028). Regardless of patellofemoral disease severity, 93% of UKAs were satisfied or very satisfied.

CONCLUSION

Clinical outcomes of fixed-bearing medial UKA were not adversely impacted by intraoperatively visualized or radiographically evaluated patellofemoral disease. Furthermore, long-term follow-up is warranted and caution should be used before considering patellofemoral disease as a contraindication for UKA.

General Anesthesia Leads to Increased Adverse Events Compared With Spinal Anesthesia in Patients Undergoing Unicompartmental Knee Arthroplasty

BACKGROUND

The volume of unicompartmental knee arthroplasty (UKA) has increased dramatically in recent years with good reported long-term outcomes. UKA can be performed under general or neuraxial (ie, spinal) anesthesia; however, little is known as to whether there is a difference in outcomes based on anesthesia type. The purpose of the present study is to compare perioperative outcomes between anesthesia types for patients undergoing primary elective UKA.

METHODS

Patients who underwent primary elective UKA from 2007 to 2017 were identified from the American College of Surgeons-National Surgical Quality Improvement Program Database. Operating room times, length of stay (LOS), 30-day adverse events, and readmission rates were compared between patients who received general anesthesia and those who received spinal anesthesia. Propensity-adjusted multivariate analysis was used to control for selection bias and baseline patient characteristics.

RESULTS

A total of 8639 patients underwent UKA and met the inclusion criteria for this study. Of these, 4728 patients (54.7%) received general anesthesia and 3911 patients (45.3%) received spinal anesthesia. On propensity-adjusted multivariate analyses, general anesthesia was associated with increased operative time (P < .001) and the occurrence of any severe adverse event (odds ratio [OR], 1.39; 95% confidence interval [95% CI], 1.04-1.84; P = .024). In addition, general anesthesia was associated with higher rates of deep venous thrombosis (OR, 2.26; 95% CI, 1.11-4.6; P = .024) and superficial surgical site infection (OR, 1.04; 95% CI, 0.6-1.81; P < .001). Finally, general anesthesia was also associated with a reduced likelihood of discharge to home (OR, 0.72; 95% CI, 0.59-0.88; P < .001). No difference existed in postoperative hospital LOS or readmission rates among cohorts.

CONCLUSION

General anesthesia was associated with an increased rate of adverse events and increased operating room times as well as a reduced likelihood of discharge to home. There was no difference in hospital LOS or postoperative readmission rates between anesthesia types.

Should patients aged 75 years or older undergo medial unicompartmental knee arthroplasty? A propensity score-matched study

INTRODUCTION

With increasing life expectancies worldwide, more elderly patients with isolated medial compartment osteoarthritis may become suitable UKA candidates. However, there is a paucity of literature comparing outcomes between older patients (≥ 75 years) and younger patients undergoing UKA. The aim of this study was to determine if there were differences in functional and HRQoL measures between older patients (≥ 75 years) and younger controls (< 75 years) undergoing primary UKA.

MATERIALS AND METHODS

Prospectively collected registry data of 1041 patients who underwent primary, cemented, fixed-bearing medial UKA at a single institution from 2002-2013 were reviewed. Propensity scores generated using logistic regression was used to match older patients (≥ 75 years, n = 94) to controls (< 75 years, n = 188) in a 1:2 ratio. Knee Society Scores, Oxford Knee Score, Short Form-36, satisfaction/expectation scores, proportion of patients attaining OKS/SF-36 PCS MCID and survivorship were analysed.

RESULTS

Patients ≥ 75 years had significantly lower KSFS (67.1 ± 17.9 vs 79.4 ± 18.2, p < 0.001) and SF-36 PCS (47.3 ± 10.1 vs 50.4 ± 9.1, p = 0.01) as compared to the control group. In addition, a significantly lower proportion of patients ≥ 75 years attained MCID for SF-36 PCS when compared to the controls (50.0% vs 63.8%, p = 0.04). Survival rates at mean 8.3 ± 3.0 years were 98.9% (95% CI, 96.7-100) in the older group versus 92.8% (95% CI, 86.8-98.8) in the younger group (p = 0.31).

CONCLUSIONS

Our findings highlight the need to counsel older patients regarding potentially reduced improvements in functional outcomes, despite advantages of lower revision. However, UKA in older patients continues to be a viable option for isolated medial compartment osteoarthritis LEVEL OF EVIDENCE: Level III Propensity score matched study.

Postoperative outcomes of total knee arthroplasty compared to unicompartmental knee arthroplasty: A matched comparison

BACKGROUND

The purpose of this study was to evaluate early postoperative outcomes in patients following UKA (unicompartmental knee arthroplasty) compared to a matched cohort of TKA (total knee arthroplasty) patients.

METHODS

Patients who met radiographic criteria for a medial UKA who underwent either a TKA or UKA at a single institution were matched based on age, gender, and BMI.

RESULTS

One hundredy and fifty UKA in 138 patients and 150 TKA in 148 patients were included in this retrospective analysis. Mean age was 62.6 ± 9 years and 65.2 ± 9 years in the UKA and TKA groups respectively (p = .01). Patients who underwent UKA had significantly less pain at two and six weeks postoperatively compared to TKA patients with mean Numeric Pain Rating Scale (NPRS) scores of 3.7 ± 1.1 vs. 7.8 ± 1.2, p < .001 and 2.6 ± 1.3 vs. 4.6 ± 1.6, p < .001 respectively. Knee Society Scores (KSS) were higher in the UKA group at six weeks and two years postoperative (86.5 ± 2.8 vs. 81.4 ± 3.6, p < .001 and 89.5 ± 2.4 vs. 84.5 ± 3.3, p < .001 respectively). Return to work was faster in the UKA group (mean 20.6 ± 7.89 vs. 38.6 ± 6.23 days, p < .001). The UKA group also had higher mean Forgotten Joint Scores of 90.5 ± 3.6 vs. 79.5 ± 9.5 (p < .001).

CONCLUSIONS

Patients with primarily medial compartment OA who underwent UKA had less postoperative pain, earlier return to work, and higher KSS compared to a matched group who underwent TKA.

Early post-operative opioid consumption: A comparison between medial unicompartmental, patellofemoral, and total knee arthroplasty

BACKGROUND

While there is emerging literature describing the use of narcotics for post-operative pain control following TKA, little data is available regarding narcotic use in partial knee replacements. The aim of this study is to compare the early post-operative narcotic requirements after medial compartmental arthroplasty (UKA) and patellofemoral arthroplasty (PFA) with that of TKA.

METHODS

In this retrospective chart review, we identified 37 patients who underwent PFA and 71 patients who underwent UKA. We identified a cohort of TKA patients who were matched to the unicompartmental group based on sex and age (n = 108). The primary outcome measure was self-reported use of opioids for pain management at the first post-operative clinic visit. Opioid use between groups was compared using Chi-square analysis.

RESULTS

The PFA group was younger (p < 0.001) and consisted of more females (p < 0.001) than the UKA group. The UKA cohort had more non-smoking patients (p = 0.044) compared to the PFA cohort. Self-reported opioid use at the first post-operative visit differed between the three groups of patients (p < 0.001). A greater proportion of both PFA (38% vs. 11%; p < 0.001) and TKA (41% vs. 11%; p = 0.01) patients reported opioid use when compared to UKA patients. No differences in opioid use existed between TKA and PFA groups (p = 0.61).

CONCLUSION

The prevalence of PFA patients who report opioid use at the first post-operative visit is similar to that for patients following TKA, suggesting that pain management protocols for this specific subset of partial knee arthroplasty patients should be structured similar to TKA patients and separate from UKA patients.

Influence of bone density on morphologic cement penetration in minimally invasive tibial unicompartmental knee arthroplasty: an in vitro cadaver study

Background

Unicompartmental knee arthroplasty is an established treatment option for anteromedial osteoarthritis. However, large registry studies report higher rates of aseptic loosening compared to total knee arthroplasty. The objective of this study was to assess the impact of bone density on morphological cement penetration. Moreover, an alternative regional bone density measuring technique was validated against the established bone mineral density assessment.

Methods

Components were implanted on the medial side of 18 fresh-frozen cadaver knees using a minimally invasive approach. Bone density has been quantified prior to implantation using Hounsfield units and bone mineral density. Morphological cement penetration has been assessed in different areas and was correlated with local bone density.

Findings

A highly significant correlation between Hounsfield units and trabecular bone mineral density was detected (r = 0.93; P < 0.0001), and local bone density was significantly increased in the anterior and posterior area (P = 0.0003). The mean cement penetration depth was 1.5 (SD 0.5 mm), and cement intrusion into trabecular bone was interrupted in 31.8% (SD 23.7%) of the bone-cement interface. Bone density was correlated significantly negative with penetration depth (r = − 0.31; P = 0.023) and positive with interruptions of horizontal interdigitating (r = + 0.33; P = 0.014). Cement penetration around the anchoring peg was not significantly correlated with bone density.

Interpretation

Areas with high bone density were characterized by significantly lower penetration depths and significantly higher areas without cement penetration. Anchoring pegs facilitate cement intrusion mechanically. Regional quantification of bone density using Hounsfield units is a simple but valuable extension to the established determination of bone mineral density.

The forgotten joint score in total and unicompartmental knee arthroplasty: a prospective cohort study

PURPOSE

The purpose of this study was to assess whether unicompartmental knee arthroplasty (UKA) results in better patient-reported and clinical outcome than total knee arthroplasty (TKA). The study hypothesis was UKA yields better patient-reported and clinical outcomes than TKA.

METHODS

Our prospective cohort study compared patients who underwent medial UKA or TKA from February 2014 through June 2015. Forgotten Joint Score (FJS), the short form of the Knee Injury and Osteoarthritis Outcome Score (KOOS PS), EuroQOL Five Dimensions Questionnaire (EQ-5D), and the Knee Society Score (KSS) were completed at two weeks, six weeks, three months, six months, and one year post-operatively. The KOOS PS, EQ-5D, and the KSS were also documented pre-operatively.

RESULTS

Fifty-seven patients (57 knees) were allocated to the UKA group and 62 patients (62 knees) to the TKA group. At baseline, no statistically significant differences were observed between groups regarding patient demographics and pre-operative scores. Except for FJS at 2 weeks (p = 0.326), all postoperative scores revealed significant differences as early as two weeks and up to 12 months (p < 0.05).

CONCLUSIONS

Our findings suggest UKA patients are less aware of their joint replacements than TKA patients for medial osteoarthritis of the knee. UKA conserves more soft tissue and bone than TKA, which may be the reason for the differences observed.

Revision Analysis of Robotic Arm-Assisted and Manual Unicompartmental Knee Arthroplasty

BACKGROUND

The purpose of this study was to evaluate hospital admissions for revision surgeries associated with robotic arm-assisted unicompartmental knee arthroplasty (rUKA) vs manually instrumented UKA (mUKA) procedures.

METHODS

Patients ≥18 years of age who received either a mUKA or a rUKA procedure were candidates for inclusion and were identified by the presence of appropriate billing codes. Procedures performed between March 1, 2013 and July 31, 2015 were used to calculate the rate of surgical revisions occurring within 24-months of the index procedure. Following propensity matching, 246 rUKA and 492 mUKA patients were included. Revision rates and the associated costs were compared between the two cohorts. The Mann-Whitney U test was used to compare continuous variables, and Fisher's exact tests was used to analyze discrete categorical variables.

RESULTS

At 24 months after the primary UKA procedure, patients who underwent rUKA had fewer revision procedures (0.81% [2/246] vs 5.28% [26/492]; P = .002), shorter mean length of stay (2.00 vs 2.33 days; P > .05), and incurred lower mean costs for the index stay plus revisions ($26,001 vs $27,915; P > .05) than mUKA patients. Length of stay at index and index costs were also lower for rUKA patients (1.77 vs 2.02 days; P = .0047) and ($25,786 vs $26,307; P > .05).

CONCLUSIONS

The study results demonstrate that patients who underwent rUKA had fewer revision procedures, shorter length of stay, and incurred lower mean costs (although not statistically different) during the index admission and at 24 months postoperatively. These results could be important for payers as the prevalence of end-stage knee osteoarthritis increases alongside the demand for cost-efficient treatments.

Randomized clinical trial of medial unicompartmentel versus total knee arthroplasty for anteromedial tibio-femoral osteoarthritis. The study-protocol

BACKGROUND

In treatment of isolated medial unicondylar osteoarthritis of the knee, it is possible to choose between medial unicondylar knee arthroplasty (mUKA), or a total knee prosthesis (TKA). The demand for a blinded multicenter RCT with the comparison of mUKA and TKA has been increasing in recent years, to determine which prosthesis is better. Supporters of TKA suggest this treatment gives a more predictable and better result, whereas supporters of UKA suggest it is unnecessary to remove functional cartilage in other compartments. If the mUKA is worn or loosens, revision surgery will be relatively easy, whereas revision-surgery after a TKA can be more problematic.

METHODS

A double-blinded multicenter Randomized Clinical Trial setup is the aim of the study. 6 hospitals throughout all 5 municipal regions of Denmark will be participating in the study. 350 patients will be included prospectively. Follow-up will be with PROM-questionnaires and clinical controls up to 20 years.

DISCUSSION

Results will be assessed in terms of 1) PROM-questionnaires, 2) Clinical assessment of knee condition, 3) cost analysis. To avoid bias, all participants except the theatre-staff will be blinded.

PROMS

OKS, KOOS, SF36, Forgotten Joint Score, EQ5D, UCLA activity scale, Copenhagen Knee ROM scale, and Anchor questions. Publications are planned at 2, 5 and 10 years after inclusion of the last patient. The development of variables over time will be analyzed by calculating the area under the curve (AUC) for the variable relative to the initial value, and comparisons of the between-group differences will be based on parametric statistics. In this study, we feel that we have designed a study that will address these concerns with a well-designed double-blinded multicentre RCT.

TRIAL REGISTRATION

ClinicalTrials.gov ID: NCT03396640 . Initial Release: 09/19/2017. Date of enrolment of first participant: 10/11/17.

Medial Unicompartmental Arthroplasty of the Knee

Indications for medial unicompartmental knee arthroplasty (UKA) have expanded over the past two decades. Proposed advantages include faster recovery, improved kinematics, and better functional outcomes compared with total knee arthroplasty (TKA) in age-matched control subjects. A focused preoperative examination and imaging is essential to identify appropriate surgical candidates. No difference has been demonstrated between fixed- and mobile-bearing implants for implant survivorship or patient-reported outcomes. The most common reasons for conversion to a TKA are aseptic loosening and progression of osteoarthritis. Ten-year survival for UKA in cohort studies has shown to be >90% with outcomes after conversion to TKA being similar to outcomes for revision TKA. Registries have consistently shown lower implant survival for UKA compared with that for TKA, which is likely secondary to use of several different implants by surgeons of varying levels of experience. UKA has the potential to be a cost-effective alternative to TKA in certain patient populations when performed at high-volume centers with advanced surgical techniques.

Long-Term Survival Analysis and Outcomes of Meniscal Allograft Transplantation With Minimum 10-Year Follow-Up: A Systematic Review

PURPOSE

To investigate the long-term survivorship rates and functional outcomes of meniscal allograft transplantation (MAT) in patients with minimum 10-year postoperative follow-up.

METHODS

Two reviewers independently searched EMBASE, MEDLINE, and PubMed from database inception for literature related to MAT according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) checklist. Data are reported in a narrative summary fashion with descriptive statistics.

RESULTS

Eleven studies with a total of 658 patients and 688 MATs were included. Mean age of patients was 33.1 years (range 14-66), of whom 63% were male. Mean survivorship rates were 73.5% at 10-year and 60.3% at 15-year follow-up, with 2 studies reporting 19- and 24-year survivorship of 50% and 15.1%, respectively. Pre- and postoperative Lysholm scores ranged from 36 to 60.5 and 61 to 75, respectively. Pre- and postoperative Tegner scores ranged from 1 to 3 and 2.5 to 4.6, respectively. Postoperative Knee injury and Osteoarthritis Outcome Score subset scores were as follows: Pain: 61.6 to 76.3; Symptoms: 57.9 to 61.8; Function in Daily Living: 68.5 to 79.9; Sport and Recreation: 33.9 to 49.3; Quality of Life: 37.3 to 45.9. Postoperative International Knee Documentation Committee scores ranged from 46 to 77. Regarding surgical technique, 194 MAT bone-fixation technique (53.8%) and 165 MAT suture-only fixation techniques (46.2%) were reported. The most common type of allograft used was cryopreserved (54.5% of the allografts). The most frequent concomitant procedures performed with MAT were to address chondral (20.8% of the cases) and ligament injuries (12.4% of the cases), and realignment procedures (9.4% of the cases). The most common complications observed that were not directly related to concomitant procedures were meniscal allograft partial tears (11.1%), arthrofibrosis (3.6%), and infection (2.0%). Several criteria were used among studies to define failure of MAT, the most common parameters being removal of meniscal allograft (8/11 studies) and conversion to total knee arthroplasty (7/11 studies).

CONCLUSIONS

MAT can yield good long-term survivorship rates, with 73.5% and 60.3% of allografts remaining functional after 10 and 15 years, respectively. Functional outcomes 10 years after MAT were fair and improved compared with preoperative scores.

LEVEL OF EVIDENCE

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

Management of Chondral Lesions of the Knee: Analysis of Trends and Short-Term Complications Using the National Surgical Quality Improvement Program Database

PURPOSE

To provide updated surgical trends of cartilage procedures differentiated by the classic groups of palliative, repair, and restorative modalities.

METHODS

The American College of Surgeons National Surgical Quality Improvement Program database was queried from 2010-2016 for the following cartilage procedures: chondroplasty, microfracture, arthroscopic osteochondral autograft or allograft transplantation, open osteochondral autograft or allograft transplantation, and autologous chondrocyte implantation. Demographic variables and short-term (30-day) complications were analyzed with 1-way analysis of variance and post hoc analysis. Linear regression analysis was performed to analyze trends over time.

RESULTS

A total of 15,609 procedures performed between 2010 and 2016 were analyzed. On average, 342.2 ± 27.9 cartilage procedures were performed per 100,000 operations. There was a linear increase in the management of overall cartilage procedures per 100,000 operations (P = .002). There were also linear increases in arthroscopic osteochondral autograft transplantation, arthroscopic osteochondral allograft transplantation, open osteochondral autograft transplantation, open osteochondral allograft transplantation, and autologous chondrocyte implantation (P < .001, P = .037, P = .001, P = .006, and P = .002, respectively). Meniscectomy was the most frequently performed concomitant procedure (9.7%-64.2% of cases). Chondroplasty and microfracture showed no change in frequency over time (P = .140 and P = .720, respectively). The overall complication rate was 2.1% for chondroplasty, 1.4% for microfracture, 1.8% for arthroscopic osteochondral autograft transplantation, 1.0% for arthroscopic osteochondral allograft transplantation, 1.4% for open osteochondral autograft transplantation, 1.1% for open osteochondral allograft transplantation, and 0.75% for autologous chondrocyte implantation. Deep vein thrombosis was the most common complication, occurring in 0.4% to 1.0% of cases. No statistically significant difference was found in complication rates between procedures (P = .105).

CONCLUSIONS

Cartilage restoration is becoming an increasingly popular modality to address chondral defects. Minimal complication rates suggest that these procedures may be safely performed concomitantly with other interventions.

LEVEL OF EVIDENCE

Level IV, retrospective database analysis.

Unicompartmental versus total knee arthroplasty for knee osteoarthritis

PURPOSE

In the last couple of years, a significant amount of studies comparing the UKA and TKA for unicompartmental knee osteoarthritis have been published. However, there is a lack of recent meta-analysis comparing the two implants. Since the number of performed UKAs is currently increasing and the indications are obsolete, it becomes important to update current evidences and outcomes. With these premises, a meta-analysis of clinical trials comparing UKA versus TKA was conducted.

METHODS

In October 2018, the following databases were accessed: Cochrane Systematic Reviews, Scopus, PubMed and Google Scholar. According to the Oxford Center of Evidence-based Medicine, level of evidence articles I to III were included. Only studies reporting quantitative data concerning the outcomes of interest were included. For the statistical analysis and the methodological quality assessment, we referred to the Review Manager Software 5.3. Dichotomous data were analyzed through the Mantel-Haenszel statistical method with the odd ratio effect measure. For continuous data, the inverse variance statistical method was used with the mean difference effect measure. A confidence interval of 95% was considered for analysis. To evaluate study heterogeneity, both Chi-square and Higgins tests were performed. Values of P < 0.05 were considered statistically significant.

RESULTS

The overall methodological quality assessment was moderate. The risk of publication's bias was moderate. We enrolled in this study a total of 13,789 patients. The mean follow-up was 42.69 months. The UKA evidenced increased risk of revision's surgeries (OR 2.16, P > 0.0001). All the other scores of interest were in favor of the UKA: Oxford Knee Score, KSS Clinical, WOMAC overall and related subscales. The UKA also reported better functional outcomes: KSS Function, longer walking distance, improvement of the joint flexion and ROM. Moreover, in the UKA group have been reported a shorter length of stay, reduced estimated total blood loss and shorter surgical duration.

CONCLUSION

The main findings of this meta-analysis are that UKA reported a reduced survivorship but better clinical and functional performances compared to TKA. Furthermore, shorter surgical duration, lower total estimated blood loss and quicker hospitalization length were observed in the UKA cohort.

Creating Value in Plastic Surgery

Value is defined as the worth, utility, or importance something holds. It can be derived from a variety of goods and services and is relative to a given industry or population. This article will discuss elements of plastic surgery that hold value as to how it pertains to the key players in a medical transaction. It will also discuss strategies for identifying and generating value. Roles of the different members in a plastic surgery transaction were analyzed, specifically the patient, the surgeon, and the facility. Different factors that generated value for all parties were identified throughout the literature. Factors identified that created value included the following: the surgeon's knowledge, experience, and decision-making ability; and technical skill/speed, restoration of life, restoration of form and function, restoration of psychological deficit, instant surgical results, convenience of access, outcomes, cost accounting, research, compassion, and bedside manner. Plastic surgeons can gear their practice to provide the system and their patients with services that hold value. We present several factors that can generate value for the patient, surgeon, and hospital system.

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

BACKGROUND

There has been increased utilization of surgical options for the treatment of end-stage unicompartmental arthritis in patients at both extremes of the age spectrum. The purpose of this study was to determine how these changing paradigms affected the lifetime cost-effectiveness of total knee arthroplasty (TKA), unicompartmental knee arthroplasty (UKA), and nonsurgical treatment (NST).

METHODS

Using a Markov decision analytic model, we assessed how lifetime costs and quality-adjusted life years (QALYs) vary as a function of age at the time of initial treatment (ATIT) of patients with end-stage unicompartmental knee osteoarthritis undergoing TKA, UKA, and NST. Separate models were estimated for ATITs at 5-year intervals from 40 through 90 years. Direct medical costs, QALYs, and transition probabilities were determined from the published literature. Indirect costs (lost wages, Social Security disability collections, and value of missed workdays) were calculated. Cost-effectiveness and incremental cost-effectiveness ratios (ICERs) were calculated for each treatment at each ATIT. The model assumed no crossover from NST to UKA or TKA. ICERs were compared with a willingness-to-pay threshold of 50,000 U.S. dollars, and a 1-way sensitivity analysis was used to assess the robustness of ICER-based treatment decisions. Societal savings were estimated.

RESULTS

In the base-case model, surgical treatments were less expensive and provided a greater number of QALYs than NST from 40 to 69 years of age. From 70 years of age and onward, surgical treatments remained cost-effective compared with NST, with ICERs remaining below the societal willingness-to-pay threshold. When surgical treatments were compared, UKA dominated TKA for all ATITs. The preferential use of UKA in all U.S. patients with unicompartmental osteoarthritis would result in an estimated lifetime societal savings of 987 million to 1.5 billion U.S. dollars per annual wave of patients undergoing treatment.

CONCLUSIONS

In this preliminary assessment, recent expansion of surgical treatments into younger and older age demographics appears to be cost-effective in the setting of unicompartmental knee osteoarthritis. Our findings suggest that NST should be used sparingly in patients below the age of 70 years and UKA should be chosen over TKA in order to maximize cost-effectiveness.

LEVEL OF EVIDENCE

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

Cost-effectiveness of unicompartmental compared with total knee replacement: a population-based study using data from the National Joint Registry for England and Wales

OBJECTIVES

To assess the value for money of unicompartmental knee replacement (UKR) compared with total knee replacement (TKR).

DESIGN

A lifetime Markov model provided the framework for the analysis.

SETTING

Data from the National Joint Registry (NJR) for England and Wales primarily informed the analysis.

PARTICIPANTS

Propensity score matched patients in the NJR who received either a UKR or TKR.

INTERVENTIONS

UKR is a less invasive alternative to TKR, where only the compartment affected by osteoarthritis is replaced.

PRIMARY OUTCOME MEASURES

Incremental quality-adjusted life years (QALYs) and healthcare system costs.

RESULTS

The provision of UKR is expected to lead to a gain in QALYs compared with TKR for all age and gender subgroups (male: <60 years: 0.12, 60-75 years: 0.20, 75+ years: 0.19; female: <60 years: 0.10, 60-75 years: 0.28, 75+ years: 0.44) and a reduction in costs (male: <60: £-1223, 60-75 years: £-1355, 75+ years: £-2005; female: <60 years: £-601, 60-75 years: £-935, 75+ years: £-1102 per patient over the lifetime). UKR is expected to lead to a reduction in QALYs compared with TKR when performed by surgeons with low UKR utilisation but an increase among those with high utilisation (<10%, median 6%: -0.04, ≥10%, median 27%: 0.26). Regardless of surgeon usage, costs associated with UKR are expected to be lower than those of TKR (<10%: £-127, ≥10%: £-758).

CONCLUSIONS

UKR can be expected to generate better health outcomes and lower lifetime costs than TKR. Surgeon usage of UKR does, however, have a significant impact on the cost-effectiveness of the procedure. To achieve the best results, surgeons need to perform a sufficient proportion of knee replacements as UKR. Low usage surgeons may therefore need to broaden their indications for UKR.

Unicompartmental knee replacement - Current perspectives

Unicompartmental knee replacement (UKR) is an effective treatment for end-stage, symptomatic unicompartmental osteoarthritis of the knee. However, certain aspects of the procedure are still debated. These areas of discussion include patient selection criteria, implant design and the discrepancy in survival rates between national registries and independent case series. These may contribute in limiting the more widespread acceptance of unicompartmental knee replacement. The aim of this paper is to review the up-to-date evidence on UKR and discuss the most relevant controversies regarding this procedure.

Choosing Between Unicompartmental and Total Knee Replacement: What Can Economic Evaluations Tell Us? A Systematic Review

BACKGROUND AND OBJECTIVE

Patients with anteromedial arthritis who require a knee replacement could receive either a unicompartmental knee replacement (UKR) or a total knee replacement (TKR). This review has been undertaken to identify economic evaluations comparing UKR and TKR, evaluate the approaches that were taken in the studies, assess the quality of reporting of these evaluations, and consider what they can tell us about the relative value for money of the procedures.

METHODS

A search of MEDLINE, EMBASE and the Centre for Reviews and Dissemination National Health Service Economic Evaluation Database was undertaken in January 2016 to identify relevant studies. Study characteristics were described, the quality of reporting and methods assessed using the Consolidated Health Economic Evaluation Reporting Standards (CHEERS) checklist, and study findings summarised.

RESULTS

Twelve studies satisfied the inclusion criteria. Five were within-study analyses, while another was based on a literature review. The remaining six studies were model-based analyses. All studies were informed by observational data. While methodological approaches varied, studies generally had either limited follow-up, did not fully account for baseline differences in patient characteristics or relied on previous research that did not. The quality of reporting was generally adequate across studies, except for considerations of the settings to which evaluations applied and the generalisability of the results to other decision-making contexts. In the short-term, UKR was generally associated with better health outcomes and lower costs than TKR. Initial cost savings associated with UKR seem to persist over patients' lifetimes even after accounting for higher rates of revision. For older patients, initial health improvements also appear to be maintained, making UKR the dominant treatment choice. However, for younger patients findings for health outcomes and overall cost effectiveness are mixed, with the difference in health outcomes depending on the lifetime risk of revision and patient outcomes following revision.

CONCLUSIONS

UKR appears to be less costly than TKR. For older patients, UKR is also expected to lead to better health outcomes, making it the dominant choice; however, for younger patients health outcomes are more uncertain. Future research should better account for baseline differences in patient characteristics and consider how the relative value of UKR and TKR varies depending on patient and surgical factors.

Preoperative Interventions and Charges in the 2-Year Period Before Unicompartmental Knee Arthroplasty: What Happens Before Surgery

BACKGROUND

This study investigated preoperative interventions and their costs in the 2-year period before a patient undergoing a unicompartmental knee arthroplasty (UKA).

METHODS

A retrospective cohort analysis of patients undergoing UKA between 2009 and 2011 was conducted using the PearlDiver Patient Record Database to track inpatient and outpatient billing records.

RESULTS

One thousand eight hundred forty-one patients from Medicare and 4704 patients from United Healthcare underwent UKA between 2009 and 2011. In the 2 years before UKA, the per patient average charge was $3919.96 for Medicare patients and $5219.14 for United Healthcare patients, with 21.7% of Medicare-associated charges and 28.2% of United Healthcare-associated charges occurring within 3 months of surgery. In the 2-year period before surgery, 65.5% of Medicare patients and 53.6% of United Healthcare patients received an intra-articular injection, with 29.1% (Medicare) and 46.0% (United Healthcare) of these injections occurring within 3 months of surgery. In addition, 15.1% of Medicare patients and 20.7% of United Healthcare patients underwent an arthroscopy, with between 32.4% and 43.8% of these occurring in the final 6 months before UKA.

CONCLUSION

Preoperative interventions (ie, imaging, procedures, physical therapy, and injections) occur at a high frequency in close proximity to UKA resulting in substantial costs. The development of algorithms to guide management of these patients is critical in reducing costs before UKA.

Mid-Term Outcomes of Metal-Backed Unicompartmental Knee Arthroplasty Show Superiority to All-Polyethylene Unicompartmental and Total Knee Arthroplasty

BACKGROUND

Two commonly used tibial designs for unicompartmental knee arthroplasty (UKA) are all-polyethylene "inlay" and metal-backed "onlay" components. Biomechanical studies showed that the metal baseplate in onlay designs better distributes forces over the tibia but studies failed to show differences in functional outcomes between both designs at mid-term follow-up. Furthermore, no studies have compared both designs with total knee arthroplasty (TKA).

QUESTIONS/PURPOSES

The goal of this study was to compare outcomes of inlay UKA and onlay UKA at mid-term follow-up and compare these with TKA outcomes.

METHODS

In this retrospective study, 52 patients undergoing inlay medial UKA, 59 patients undergoing onlay medial UKA, and 59 patients undergoing TKA were included. Western Ontario and McMaster Universities Arthritis Index scores were collected preoperatively and at mean 5.1-year follow-up (range 4.0-7.0 years).

RESULTS

Preoperatively, no differences were observed in patient characteristics or outcome scores. At mid-term follow-up, patients undergoing onlay medial UKA reported significant better functional outcomes than those of inlay medial UKA (92.0 ± 10.4 vs. 82.4 ± 18.7, p = 0.010) and when compared to TKA (92.0 ± 10.4 vs. 79.6 ± 18.5, p < 0.001) while no significant differences between inlay medial UKA and TKA were noted. No significant differences in revision rates were found.

CONCLUSION

Functional outcomes following onlay metal-backed medial UKA were significantly better compared to inlay all-polyethylene medial UKA and to TKA. Based on the results of this study and on biomechanical and survivorship studies in the literature, we recommended using metal-backed onlay tibial components for unicompartmental knee arthroplasty.

Cost effectiveness of patellofemoral versus total knee arthroplasty in younger patients

AIMS

Patellofemoral arthroplasty (PFA) has experienced significant improvements in implant survivorship with second generation designs. This has renewed interest in PFA as an alternative to total knee arthroplasty (TKA) for younger active patients with isolated patellofemoral osteoarthritis (PF OA). We analysed the cost-effectiveness of PFA versus TKA for the management of isolated PF OA in the United States-based population.

PATIENTS AND METHODS

We used a Markov transition state model to compare cost-effectiveness between PFA and TKA. Simulated patients were aged 60 (base case) and 50 years. Lifetime costs (2015 United States dollars), quality-adjusted life year (QALY) gains and incremental cost-effectiveness ratio (ICER) were calculated from a healthcare payer perspective. Annual rates of revision were derived from the National Joint Registry for England, Wales, Northern Ireland and the Isle of Man. Deterministic and probabilistic sensitivity analysis was performed for all parameters against a $50 000/QALY willingness to pay.

RESULTS

PFA was more expensive ($49 811 versus $46 632) but more effective (14.3 QALYs versus 13.3 QALYs) over a lifetime horizon. The ICER associated with the additional effectiveness of PFA was $3097. The model was mainly sensitive to utility values, with PFA remaining cost-effective when its utility exceeded that of TKA by at least 1.0%. PFA provided incremental benefits at no increased cost when annual rates of revision decreased by 24.5%.

CONCLUSIONS

Recent improvements in rates of implant of survival have made PFA an economically beneficial joint-preserving procedure in younger patients, delaying TKA until implant failure or tibiofemoral OA progression. The present study quantified the minimum required marginal benefit for PFA to be cost-effective compared with TKA and identified survivorship targets for PFA to become both less expensive and more effective. These benchmarks might be used to assess clinical outcomes of PFA from an economic standpoint within the United States healthcare system. Cite this article: Bone Joint J 2017;99-B:1028-36.