Ninety‐three point seven percent pooled 10‐year survival rate following lateral unicompartmental knee arthroplasty for isolated lateral knee osteoarthritis—A systematic review and meta‐analysis

Purpose To systematically review the available evidence on long‐term outcomes following lateral unicompartmental knee arthroplasty in lateral knee osteoarthritis. Methods An advanced search was done throughout three electronic databases (PubMed, Scopus and Embase) involving the words ‘lateral unicompartmental knee arthroplasty’ and ‘lateral knee osteoarthritis’. Inclusion and exclusion criteria were set. The Newcastle‐Ottawa scale was used in assessing the study quality. Extracted were study demographics, survival rate, follow‐up period, indications and contraindications, implant type, revision rate and outcome tools. The data were systematically collected and meta‐analysed. Results After an initial screening of 1864 articles, 15 articles were selected for the review. The study quality was evaluated as ‘high’ in most of the selected articles. The pooled 10‐year survival rate was 93.7% (95% CI: 92.5%−94.9%). The mean follow‐up period ranged between 7 and 14 years (pooled mean follow‐up 9.1 years). A significant negative correlation was found between patient BMI and survival rate ( p = 0.03). Female participants were prevalent among the studies; however, no strong evidence linked the male proportion and survival rate ( p > 0.05). The pooled revision rate was 4.6%. Conclusions Lateral unicompartmental knee arthroplasty for isolated lateral knee osteoarthritis provided a high long‐term survival rate with a low 10‐year revision rate. This was provided in a non‐ACL‐deficient knee with a preoperative flexion of above 90 degrees and a correctable valgus by using a fixed‐bearing implant. Females were more likely to undergo this procedure. A negative correlation was found between patient BMI and survival rate. There was a notable variability in the reported outcome measures among studies. Level of Evidence Level IV, systematic review of therapeutic studies.