Greater knee flexion and patient-reported function after unicompartmental knee arthroplasty than after total knee arthroplasty: a propensity score-matched study.

PURPOSE: The purpose of this study was to compare knee range of motion and 2011 Knee Society Score (2011KSS) after unicompartmental knee arthroplasty (UKA) and total knee arthroplasty (TKA) in background-matched cohort.

METHODS

UKA and TKA for medial knee osteoarthritis were included, and preoperative patient backgrounds, knee alignment, osteoarthritis severity, knee range of motion, 2011KSS symptoms, satisfaction and functional activities were matched using a propensity score. Knee range of motion and 2011KSS were evaluated two year postoperatively.

RESULTS

Among 116 UKAs and 656 TKAs, 98 each arthroplasty were matched (mean 75 years). UKA showed greater knee flexion (mean: 136.6° vs 122.4°, p < 0.001) and 2011KSS functional activities (median: 78 vs 68, p = 0.04) at 2-year. There were no differences in knee extension or other 2011KSS domains.

CONCLUSION

UKA showed greater knee flexion and subjective functional score than TKA. UKA may be beneficial for populations with high flexion demands.