In Patients With Crowe Type III and Crowe Type IV Hip Dysplasia, Mid-Term Lower Extremities and Spine After Total Hip Arthroplasty Natural Course

Developmental hip dysplasia (DDH) describes the spectrum of anatomical changes in the acetabulum and proximal femur; these can cause limping, lower back pain, lumbar lordosis, and leg length variation. DDH is the main cause of degenerative arthritis of the hip and valgus deformity of the knee. The best treatment option for DDH is total hip arthroplasty (THA). During THA, the distorted anatomy of the acetabulum and proximal femur poses great difficulties. Additionally, the soft tissue can be released and the femur can be shortened while correcting the placement of the acetabulum to prevent neurological damage (sciatic nerve paralysis). Postoperative evaluations focused on assessing joint function and alleviating preoperative clinical symptoms. Some studies have examined changes in lower extremity and knee alignment after THA in patients with DDH. In patients with DDH, THA may cause genu valgus deformity due to increased lower extremity length and Q angle immediately after the operation. THA extends the lower extremity, affecting the patellofemoral joint and anterior knee pain. However, the long-term effects of THA on the alignment of the lower extremity are unclear, especially in patients with Crowe type III and IV DDH, which involves femoral shortening osteotomy. There are few studies examining changes in the knee and lower extremities as a result of THA in patients with DDH. The aim of this study is to evaluate the mid- and long-term alignment of the spine and lower extremity after THA with or without femoral shortening osteotomy in patients with unilateral DDH (Crowe type III-IV).