[Propensity score-matched study of uni-condylar arthroplasty in elderly patients with knee osteoarthritis]

To investigate the clinical efficacy of unicompartmental knee arthroplasty (UKA) in the treatment of knee osteoarthritis in patients over 75 years old.

The clinical efficacy of primary fixed platform UKA in patients with osteoarthritis, was retrospectively analyzed from October 2014 to November 2020. Age, body mass index (BMI), range of motion (ROM), preoperative joint function score, the quality of life score and other preoperative indicators were measured by propensity score matching (PSM). The patients were divided into elderly group (≥75 years old) and control group (<75 years old). Oxford knee score(OKS), Western Ontario McMaster Universities osteoarthritis index(WOMAC), Short Form-12 including physical component summary (PCS), mental component summary(MCS), minimal clinically important difference(MCID ) and clinical complications were evaluated preoperatively and postoperatively.

A total of 514 patients were analyzed, 428 patients fulfilled the inclusion criteria. A propensity-score matching study was conducted to eliminate confounding factors. After 1∶2 propensity match, there were 84 patients in elderly group (≥75 years), age ranged from 75 to 88 years old, with an average of (78.79±3.08) years old, and 168 patients in control group (<75 years), age ranged from 47 to 74 years old, with an average of (64.10±5.96)years old. The follow-up duration of two groups ranged from 12 to 84 months with an average of (29.35±16.52) months in elderly group, and 12 to 85 months with an average of (31.83±17.34) months in control group. There was only significant difference in age between the elderly and control groups preoperatively (P<0.01). Postoperatively, the elderly group showed significantly higher WOMAC (P<0.01) and lower SF-12 PCS scores (P<0.01) as compared to the control group. There was no significant difference between the elderly group and the control group in knee range of motion, OKS and the proportion of each scoring system reaching the minimum clinical difference value (P>0.05). In the aspect of preperative complications, the elderly group exhibited more surgical site complications and postoperative delirium compared to control group(P<0.05). The differences in other indicators including deep vein thrombosis, acute urinary retention, cardiovascular events, cerebrovascular events and radiolucent lines around prothesis were not statistically significant(P>0.05).

UKA in the treatment of elderly patients over 75 years old with knee osteoarthritis was safe and feasible, and could obtain satisfactory short-term efficacy.