Predictors of Inability to Kneel and/or Squat One Year after Knee Arthroplasty in a Southeast Asian Population.

Abstract

The ability to kneel and squat after knee arthroplasty is a key determinant of patient satisfaction, especially in Asian populations where deep-flexion postures are culturally important. However, many patients remain unable to perform these activities postoperatively. This study aimed to identify the factors influencing both the ability and inability to kneel and squat after knee arthroplasty. A retrospective analysis of 888 knees in 830 patients undergoing primary knee arthroplasty was conducted. Pre-, intra-, and postoperative variables, including range of motion (ROM), flexion, Oxford Knee Score question 4 (OKS Question 4, kneeling confidence), operation type and implant constraint, and body mass index (BMI), were analyzed. Univariate and multivariate models were used to determine predictors of the ability and inability to kneel, squat, or perform both at one year post-surgery. At one year, 42% of patients could squat, 36% could kneel, and 30% could perform both, with corresponding inability rates of 58 (squat), 64 (kneel) and 70% (both). The ability to kneel and squat correlated with greater postoperative flexion (P = 0.028), ROM (P = 0.002), and higher postoperative OKS Question 4 (P < 0.001). Conversely, inability was independently predicted by higher BMI, lower preoperative ROM and flexion, poor preoperative kneeling confidence, older age, and women (all P < 0.05). Medial unicompartmental knee arthroplasty showed a non-significant trend toward better high-flexion recovery. Functional outcomes and quality of life were substantially better in patients able to squat and kneel. This study reinforced the fact that kneeling and/or squatting cannot be achieved in roughly two-thirds of patients after knee arthroplasty surgery. Both ability and inability to kneel and squat are governed by the same factors acting in opposite directions. Optimizing preoperative BMI, ROM, and kneeling confidence through targeted prehabilitation and expectation-based counselling may enhance postoperative satisfaction and functional recovery.