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° were excluded. Postoperative range of motion (ROM) was measured prospectively. Patients were stratified into two groups: preoperative ROM < 110° and preoperative ROM ≥ 110°. 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° had a poorer postoperative range of motion at both 6-months and 2-years of follow-up than Group of ROM ≥ 110° (P < 0.001). Postoperatively, Group of ROM < 110° had gained range of motion whereas Group of ROM ≥ 110° 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.