Focal resurfacing of the knee - A systematic review and meta-analysis.

PURPOSE: In order to assess the published validity of focal resurfacing of the knee, a systematic review and meta-analysis were conducted to (i) evaluate revision rates and implant survival of focal resurfacing of the knee; (ii) explore surgical complications; and (iii) evaluate patient reported clinical outcome measures.

METHODS: PubMED, Cochrane Library and Medline databases were searched by 2 independent reviewers in February 2022 for prospective and retrospective cohort studies evaluating any of the following implant types: HemiCAP®, UniCAP®, Episealer® or BioBoly®. Data on incidence of revision, complications and various patient reported outcome measures, such as Knee Society Score (KSS) or Knee Injury and Osteoarthritis Outcome Score (KOOS) was sourced.

RESULTS: A total of 24 published studies were identified with a total of 1465 enrolled patients. A revision rate of 12.97% over a 5.9 year weighted mean follow-up period was observed across all implant types. However, in one series a Kaplan-Meir survival as high as 92.6% at a 10-year follow-up period was noted. A statistically significant improvement was documented across multiple subjective clinical outcomes scores, for example a mean 4.56 point improvement of the VAS (0-10) pain score. The Kellgren-Lawrence score was used to evaluate the radiological progression of osteoarthritis and showed a small significant reduction in all anatomical locations, hence not supporting the hypothesis that focal femoral implants can lead to the progression of osteoarthritis in the affected compartment. There was a low reported incidence of post-operative complications such as aseptic loosening or deep wound infection.

CONCLUSIONS: Focal femoral resurfacing appears to be a viable treatment option for focal symptomatic chondral lesions in patients beyond biological reconstruction, with low revision rates and high patient satisfaction especially at short and medium length follow-up.