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Less patellofemoral contact stress seen with intraoperative medial vs. non-medial pivot kinematic patterns
Compared with knees that demonstrated non-medial pivot kinematic patterns, knees with intraoperative medial pivot kinematic patterns had a significant reduction of patellofemoral contact pressure after total knee arthroplasty performed with a mobile bearing, according to the results of this study.
Researchers used a CT-guided navigation system to evaluate the intraoperative knee kinematics and patellofemoral contact stresses of 46 knees with medial knee osteoarthritis that underwent total knee arthroplasty with a posterior-stabilized total knee prosthesis. Based on intraoperative knee kinematic patterns, researchers divided patients into either medial pivot or non-medial pivot groups.
Compared with the non-medial pivot group, the medial pivot group experienced significantly lower mean maximum patellofemoral stress, according to the study. Researchers found a femoral component rotation of 0.58° internal rotation in the medial pivot group vs. 1.97° internal rotation in the non-medial pivot group.
When researchers planned femoral component rotation with navigation, results showed intraobserver surgical epicondylar axis measurement consistency with the coefficient of variation. Intraobservational coefficient of variation was 0.8% and interobservational coefficient of variation was 2.1%, according to study results.
Disclosure: Majima is on the speakers bureau for DePuy Japan and Smith & Nephew; is a paid consultant for Robert Reid Inc. and MicroPort Orthopedics; received research support from DePuy Japan and Smith & Nephew Japan; is on the editorial board for Sports Health Journal and the Journal of Orthopedic Science; and is a board member of the Asia Pacific Knee Society.