Effect of Converting Kinematic Aligned Total Knee Arthroplasty to Mechanical Axis Revision Total Knee Arthroplasty on Gap Measurements

Soft tissue releases seen in rTKA have minimal effect on the medial laxity in extension. In specimens with only mild deviation from neutral alignment and joint line obliquity, the conversion from caliper-verified KA TKA to MA rTKA still resulted in large increases in the lateral-sided gaps, especially in the flexion space. This may create issues with current implant offerings, and surgeons should anticipate substantial augmentation or joint line adjustments when revising implants that were placed with intentional joint line obliquity.