Transposition of the medial synovial flap to repair the lateral joint capsule in total knee arthroplasty for knee osteoarthritis with permanent patellar dislocation

Abstract

Purpose To retrospectively review the early- and medium-term clinical outcomes of lateral capsulorrhaphy by medial synovial flap transposition in total knee arthroplasty for the treatment of knee osteoarthritis with permanent dislocation of the patella. Method To surgically restore the patellar trajectory in 29 patients with knee osteoarthritis associated with permanent patellar dislocation undergoing total knee arthroplasty using medial synovial flap transposition to repair the lateral joint capsule. Preoperative and 2-year postoperative conditions and knee mobility were compared using the American Knee Society score function score, UCLA activity scale score, and visual analogue (VAS) pain scores. The patients were examined radiographically for full-length knee and axial patellar reduction while standing on both lower limbs. Result The patients' American Knee Society function scores improved from 40.2 ± 12.1 preoperatively to 80.5 ± 7.3 at 2 years postoperatively (P < 0.001), and their UCLA activity class scores improved from 3.9 ± 0.6 preoperatively to 6.8 ± 0.7 at 2 years postoperatively (P < 0.001). VAS pain scores decreased from 41.8 ± 6.0 points preoperatively to 10.1 ± 3.7 at two years postoperatively (P < 0.001). Knee mobility improved from 74.6 ± 8.9 degrees preoperatively to 110.5 ± 4.5 degrees at two years postoperatively (P < 0.001), and imaging showed no signs of subluxation or dislocation of the patella in any of the patients. Conclusions The correction of the patellar trajectory in patients with osteoarthritis with permanent patellar dislocation undergoing total knee arthroplasty using medial synovial flap transposition to repair the lateral joint capsule can lead to satisfactory early and medium-term clinical results.