How often is functional range of motion obtained by manipulation for stiff total knee arthroplasty?

Purpose To evaluate how often manipulation under anesthesia (MUA) can achieve functional flexion >= 90 degrees and identify predictor for successful outcome of MUA for stiff total knee arthroplasty (TKA). Methods Demographic data, range of motion, and surgical and anesthetic information of 143 MUAs were retrospectively analyzed from 2000 to 2011. Results One-hundred thirty-six out of 143 patients (95 %) improved mean range of motion (ROM) from pre-MUA 62 +/- 17 degrees to final ROM 101 A +/- 21 degrees (p < 0.001). Flexion >= 90 degrees was achieved in 74% (106/143) of patients. Regional anesthesia was identified as predictor of successful MUA outcome (p = 0.007, OR: 8.5, 95 % CI: 1.2-66.7). Conclusions Although the proportion of patients regaining flexion >= 90 degrees following MUA was less than those patients with simple overall ROM increase, the functional flexion >= 90 degrees was achieved in the vast majority of patients with stiff TKA following MUA.