Determinants of revision and functional outcome following unicompartmental knee replacement

• Published in: Osteoarthritis and cartilage 2014-09, Vol.22 (9), p.1241-1250
• Main Authors: Liddle, A.D, Judge, A, Pandit, H, Murray, D.W
• Format: Article
• Language: English
• Subjects: Adult; Age Factors; Aged; Aged, 80 and over; Arthroplasty; Arthroplasty, Replacement, Knee - methods; Arthroplasty, Replacement, Knee - rehabilitation; Databases, Factual; England - epidemiology; Female; Follow-Up Studies; Hemiarthroplasty - methods; Hemiarthroplasty - rehabilitation; Humans; Kaplan-Meier Estimate; Knee Joint - physiopathology; Knee Prosthesis; Male; Middle Aged; Northern Ireland - epidemiology; Osteoarthritis, Knee - epidemiology; Osteoarthritis, Knee - physiopathology; Osteoarthritis, Knee - rehabilitation; Osteoarthritis, Knee - surgery; Patient Satisfaction - statistics & numerical data; Patient-reported outcome measures; Prognosis; Prosthesis Failure; Recovery of Function; Reoperation - statistics & numerical data; Rheumatology; Risk Factors; Satisfaction; Treatment Outcome; Unicompartmental knee replacement; Wales - epidemiology; Young Adult
• ISSN: 1063-4584; 1522-9653; 1522-9653
• DOI: 10.1016/j.joca.2014.07.006

Summary Objective Unicompartmental Knee Replacement (UKR) has important advantages over total knee replacement (TKR) but has a higher revision rate. Outcomes vary between centres, suggesting that risk factors for revision may be modifiable with changes to patient selection or operative technique. The objective of this study was to determine factors affecting revision, patient-reported outcome and satisfaction following UKR. Method 25,982 cases from three national databases were analysed. Multilevel multivariable regression models were used to examine the effect of patient and surgical factors on implant survival, patient-reported outcome and satisfaction at 6 months and 8 years following UKR. Results Of the 25,982 cases, 3862 (14.9%) had pre-operative and 6-month Oxford Knee Scores (OKS). Eight-year survival was 89.1% (95% confidence intervals (CI) 88.3–89.9). OKS increased from 21.9 (SD 7.6) to 37.5 (SD 9.5). Age (Hazard ratio (HR) 0.96 (95% CI 0.96–0.97) per year), male gender (HR 0.86 (95% CI 0.76–0.96)), unit size (HR 0.92 (95% CI 0.86–0.97) per case up to 40 cases/year) and operating surgeon grade (HR 0.78 (95% CI 0.67–0.91) if consultant) predicted improved implant survival. Older patients (≥75 years), and those with lower deprivation levels had superior OKS and satisfaction (adjusted mean difference 0.14 (95% CI 0.09–0.20) points per year of age and 0.93 (95% CI 0.60–1.27) per quintile of deprivation). Ethnicity, anxiety and co-morbidities also affected patient-reported outcome. Conclusions This study has identified important predictors of revision and patient-reported outcome following UKR. Older patients, who are least likely to be offered UKR, may derive the greatest benefits. Improved understanding of these factors may improve the long-term outcomes of UKR.