Abstract
Purpose
Factors influencing flexion angle of the knee before and after PS-TKA were assessed.
Methods
In 368 PS-TKA cases (71 males and 297 females) by means of modified gap control technique with Stryker NRG system, multi-variance analysis was performed to assess factors influencing flexion angle before TKA and flexion angle 3 weeks after TKA. Their mean age was 74.1 years old. Operative techniques and angle of the components were included as the factors.
Results
Factors that influenced the flexion angle before TKA were BMI (standard regression coefficient, −0.166), standing femoro-tibial angle (−0.140), external rotation angle of the femoral component relative to the posterior condylar line (0.220) and resurfacing the patella (−0.225). Factors that influenced the flexion angle after TKA were flexion angle before TKA (0.491), medial soft tissue releases (−0.116) and patellar lateral release (−0.130). In cases with high BMI, severe deformity and patella damage, flexion angle before TKA was smaller. In cases in that medial soft tissues release and/or patella lateral release were necessary, flexion angle after TKA was smaller.
Conclusion
In cases with contractures and deformities, flexion angle before TKA was smaller and it was hard to obtain deep flexion angle after TKA.
