Joint awareness after unicompartmental knee arthroplasty and total knee arthroplasty: a systematic review and meta-analysis of cohort studies

Knee Surg Sports Traumatol Arthrosc. 2021 Oct;29(10):3478-3487. doi: 10.1007/s00167-020-06327-4. Epub 2020 Oct 19.


Purpose: The purpose of this systematic review and meta-analysis is to evaluate the joint awareness after unicompartmental knee arthroplasty (UKA) and total knee arthroplasty (TKA). It was hypothesized that patients with UKA could better forget about their artificial joint in comparison to TKA.

Methods: A search of major literature databases and bibliographic details revealed 105 studies evaluating forgotten joint score in UKA and TKA. Seven studies found eligible for this review were assessed for risk of bias and quality of evidence using the Newcastle-Ottawa Scale. The forgotten joint score (FJS-12) was assessed at 6 months, 1 year, and 2 years.

Results: The mean FJS-12 at 2 years was 82.35 in the UKA group and 74.05 in the TKA group. Forest plot analysis of five studies (n = 930 patients) revealed a mean difference of 7.65 (95% CI: 3.72, 11.57, p = 0.0001; I2 = 89% with p < 0.0001) in FJS-12 at 2 years. Further sensitivity analysis lowered I2 heterogeneity to 31% after exclusion of the study by Blevin et al. (MD 5.88, 95%CI: 3.10, 8.66, p < 0.0001). A similar trend of differences in FJS-12 between the groups was observed at 6 months (MD 32.49, 95% CI: 17.55, 47.43, p < 0.0001) and at 1 year (MD 25.62, 95% CI: 4.26, 46.98, p = 0.02).

Conclusions: UKA patients can better forget about their artificial joint compared to TKA patients.

Level of evidence: III.

Keywords: Forgotten joint score; Joint awareness; Joint perception; Knee; Patient satisfaction; Total knee replacement; Unicondylar knee replacement.

Publication types

  • Meta-Analysis
  • Review
  • Systematic Review

MeSH terms

  • Arthroplasty, Replacement, Knee*
  • Cohort Studies
  • Humans
  • Knee Joint / surgery
  • Osteoarthritis, Knee* / surgery
  • Treatment Outcome