The incidence and results of manipulation after primary total knee arthroplasty.

This study investigates a cohort of patients who required a manipulation after total knee arthroplasty (TKA) to determine whether there was an association between pre-TKA and post-manipulation range of motion (ROM). Thirty-seven of 800 TKAs were manipulated (4.6% incidence); complete data were available for 36 knees. The pre-TKA stiff group (<110 degrees total arc of motion; n=16), on average, had 27 degrees less arc of motion before TKA than the non-stiff group (n=20; p<0.001). Mean arc of motion in the stiff group was 68 degrees before manipulation and 109 degrees after manipulation (p<0.001). Mean arc of motion in the non-stiff group was 80 degrees before manipulation and 118 degrees after manipulation (p<0.001). Patients with pre-TKA stiffness improved from a total arc of motion of 94 to 109 (p<0.001) while patients without pre-TKA stiffness changed from 121 to 118 (p=0.169). In both groups, the success of TKA can still be high despite early motion loss and subsequent manipulation.