Total Knee Arthroplasty in Asian Subjects: Preoperative Range of Motion Determines Postoperative Range of Motion?

Objective: To evaluate whether preoperative range of motion is a key determinant of postoperative range of motion in Asian patients undergoing conventional total knee arthroplasty. Methods: A retrospective review of 302 patients who underwent primary total knee arthroplasty performed by a single surgeon was conducted. Patients who had a fixed flexion deformity of >= 15 degrees were excluded. Postoperative range of motion (ROM) was measured prospectively. Patients were stratified into two groups: preoperative ROM < 110 degrees and preoperative ROM >= 110 degrees. Postoperative ROM and mean change in ROM at 6 months and 2 years of follow-up were then compared using Student's t-test. Results: Group of ROM < 110 degrees had a poorer postoperative range of motion at both 6-months and 2-years of follow-up than Group of ROM >= 110 degrees (P < 0.001). Postoperatively, Group of ROM < 110 degrees had gained range of motion whereas Group of ROM >= 110 degrees had lost range of motion (P < 0.001). Conclusions: Similar to the Western population, preoperative range of motion is a key determinant of postoperative range of motion in Asian patients. This should be taken into consideration by surgeons during preoperative planning and in managing patients' expectations.