KSSTA - 2026-09-19 - Journal Article
Higher prearthritic activity is associated with higher long-term activity after medial unicompartmental knee arthroplasty.
Cerasoli T, Tabanelli B, Scagnol D, Di Maio L, Neri MP, Rinaldi VG, Zaffagnini S, Marcheggiani Muccioli GM
Topics
Key Takeaway
At mean 9.7-year follow-up after medial UKA, 98.1% of previously sport-active knees returned to sport, and prearthritic Tegner score independently predicted final Tegner score (regression coefficient 0.531, p<0.001).
Summary Depth
Choose how much analysis to show on this article page.
Summary
This retrospective study examined whether recalled prearthritic activity level predicts long-term sport participation after medial UKA, using the Tegner Activity Scale at three timepoints in 76 knees. Mean Tegner score recovered from 2.3 preoperatively to 3.88 at final follow-up (p<0.001 vs. preoperative; p=0.227 vs. prearthritic baseline of 4.00), with 80.3% participating in sport but only 7.9% reporting vigorous activity. Multivariable regression confirmed prearthritic Tegner score as an independent predictor of final Tegner score, with the association stable after excluding the 7 revised knees.
Key Limitation
Retrospective recall of prearthritic Tegner scores—the study's key independent variable—is subject to substantial recall bias over a mean disease course of many years, undermining the validity of the regression model's primary predictor.
Original Abstract
PURPOSE
To evaluate long-term sport participation after medial unicompartmental knee arthroplasty and determine whether recalled prearthritic activity was associated with activity at final follow-up.
METHODS
This retrospective study included 76 knees in 70 patients evaluated at a mean follow-up of 116.3 ± 31.9 months. The Tegner Activity Scale was recorded for the retrospectively recalled prearthritic period, immediately before surgery, and final follow-up. Final Tegner score was the primary outcome. Return to sport was assessed among the 54 knees with prearthritic sport participation. Multivariable linear regression used patient-clustered standard errors, and a sensitivity analysis excluded seven revised knees. No a priori sample-size calculation was performed.
RESULTS
Of 54 previously sport-active knees, 53 returned to at least one sport (98.1%). Across all 76 knees, 61 (80.3%) participated in sport and six (7.9%) reported vigorous activity at final follow-up. Mean Tegner score decreased from 4.00 ± 1.03 prearthritically to 2.3 ± 1.5 preoperatively (p < 0.001) and increased to 3.88 ± 0.78 at final follow-up (p < 0.001 vs. preoperative; p = 0.227 vs. prearthritic). Prearthritic Tegner score was associated with final Tegner score (regression coefficient, 0.531; 95% confidence interval, 0.242-0.821; p < 0.001), and the association persisted after excluding revised knees (regression coefficient, 0.519; 95% confidence interval, 0.224-0.814; p < 0.001).
CONCLUSION
Sport participation was high at nearly 10 years after medial unicompartmental knee arthroplasty, although vigorous activity was uncommon. Higher prearthritic activity was associated with higher final activity, but retrospective recall and substantial attrition limit causal and prognostic interpretation.
LEVEL OF EVIDENCE
Level IV.