Prediction of the need for manipulation under anesthesia for flexion contracture after total knee arthroplasty in patients of advanced age

OBJECTIVE: This study was performed to develop a prediction model for requiring manipulation under anesthesia (MUA) for flexion contracture after total knee arthroplasty (TKA) in patients of advanced age. METHODS: We retrospectively reviewed 269 patients of advanced age undergoing primary TKA in one center with a minimum 1-year follow-up. Patients who underwent postoperative MUA had flexion contracture of >10° after 4 weeks of postoperative rehabilitation, and their demographic data and preoperative clinical conditions [knee diagnosis, diabetes mellitus, hypertension, lumbar spinal disorders, hip disorders, ankle disorders, knee deformity (varus/valgus), preoperative flexion contracture (PFC), range of motion (ROM), and Hospital for Special Surgery (HSS) knee score] were compared with those of patients without MUA. All preoperative factors were collected to develop the predictive model. RESULTS: Thirty patients underwent MUA. Patients who underwent MUA after surgery had significant differences in PFC, higher HSS knee scores before surgery (59.10 ± 7.22 vs. 55.70 ± 13.09), and lower preoperative ROM (81.57 ± 30.86 vs. 95.47 ± 24.36) than those who did not undergo MUA. CONCLUSION: A prediction model for MUA in advanced-age patients with flexion contracture was developed and mainly consisted of preoperative risk factors including PFC, HSS scores, and ROM.