セメントレス人工股関節全置換術 (Total Hip Arthroplasty : THA) の術後thigh painに影響する因子のX線学的検討

抄録

Objective: Total hip arthroplasty (THA) is an established and excellent treatment for the painful hip. Despite good results, some patients are suffering from complications. Thigh pain is one of the complications after THA. The incidence of thigh pain after THA has not been clarified yet. The purpose of this study was to investigate clinical and radiographic factors that affect the incidence of thigh pain one year after THA.

Methods: Evaluation was performed in consecutive 89 hips (76 patients) who underwent THA from May 2015 to May 2017. Presence of thigh pain was recorded at regular follow up one year after surgery. Any complaints of the pain around the target hip joint and ipsilateral femur were recorded as thigh pain. To clarify the incidence of thigh pain, clinical features, radiographic parameters (canal filling ratio, cortical hypertrophy, cortical index, canal flare index, leg length discrepancy (LLD), femoral offset) and implant size were evaluated. These clinical features and other measured values were compared between the patients group complained thigh pain to the group without thigh pain after surgery.

Results: 27 joints had thigh pain within one year after surgery. Among them 6 joints had thigh pain one year after surgery (TP1 group). 21 joints had transient thigh pain (TP0 group). Other 62 joints had no thigh pain after surgery (N group). There were 6 stovepipe shape femurs which had no thigh pain after surgery. The mean LLD of the TP1 group was −2.5 mm before surgery. This was significantly less than the LLD values of the other two groups before surgery. The femoral offset of TP1 group patients decreased 4.1 mm on average after THA. This decrease was significant compare to the change of the femoral offset in the other two groups.

Conclusion: A decrease in the femoral offset may affect the incidence of thigh pain after THA. Therefore, it is better for the surgeon not to decrease femoral offset during surgery. Also, the LLD before surgery and the shape of the femur may affect the incidence of thigh pain after THA.