人工膝関節全置換術後にLateral Patellar Facet Syndromeを生じた2症例

抄録

 Any incongruity of the patellofemoral (PF) joint after total knee arthroplasty (TKA) results in postoperative pain and restrictions in range of motion (ROM), which is one of the major causes of revision TKA. We report our experience with two patients who developed lateral patellar facet syndrome (LPFS) following TKA.

Case 1: A 72-year-old woman underwent left TKA approximately two years previously and developed left knee pain two months postoperatively. On a physical examination, the lateral side of the PF joint demonstrated tenderness, crepitus, and ROM of the left knee was −5° in extension and 120° in flexion.

Case 2: A 69-year-old woman who underwent right TKA approximately two years previously experienced pain of the right knee and difficulty in flexion about one month postoperatively. On a physical examination, the lateral side of the PF joint demonstrated tenderness, crepitus, and the ROM of the right knee was −5° in extension and 90° in flexion.

 On radiographic examination, the impingement in both cases was between the femoral component and the lateral edge of the patella in the skyline view. We diagnosed LPFS in both cases, and at surgery, we partially cut the lateral edge of the patella, resurfaced the non-coating part of the patellar lateral component, and added a lateral release, respectively. In both cases, the tenderness on the lateral side of the PF joint disappeared in the early postoperative period, and the ROM of the knees was improved.

Discussion: Common causes of painful knee after TKA includes LPFS, where friction occurs between the femoral component and the lateral edge of patella. We suggest that when selecting the prosthetic model for TKA, the possibility of LPFS must be considered in order to try and prevent this complication.