Characteristics of three-dimensional acetabular morphology of patients with excellent outcome after rotational acetabular osteotomy over 20 years

Abstract

Background Rotational acetabular osteotomy (RAO) is a type of pelvic osteotomy performed to improve the acetabular bony coverage against the femoral head for patients with acetabular dysplasia. The acetabular bony coverage is ideally evaluated three-dimensionally; however, there is a paucity of published data regarding three-dimensional morphology in patients with long-term excellent outcome after RAO. The present study investigated the characteristics of three-dimensional acetabular morphology with long-term excellent outcome after RAO in comparison to patients with normal hip joints and those converted to total hip arthroplasty (THA) after RAO because of osteoarthritis (OA) progression. Methods Anteroposterior plain radiograph and computed tomography data of 57 hip joints (17 joints with excellent outcome 20 years or more after RAO, 16 normal joints, and 20 joints converted to THA after RAO) were analyzed. The two-dimensional lateral center-edge (CE) angle from plain radiographs and acetabular anteversion, anterior acetabular sector angle, and posterior sector angle from computed tomography (CT) images were calculated. Results Compared with patients converted to THA, all parameters in patients with long-term excellent outcome after RAO were similar to those in patients with normal hip joints, particularly in the three-dimensional analyses. The anterior bony coverage was excessive, whereas the posterior bony coverage was deficient in patients converted to THA after RAO. Anterior bony impingement and posterior instability may be the cause of OA progression after RAO. Conclusion Caution must be taken to avoid rotating the separated fragment excessively to the anterior direction during RAO to prevent OA progression and achieve long-term excellent outcome.

Eye of the Carpenter: How Well do Orthopaedic Surgeons Estimate Angular Measurements in Derotational Osteotomies?

“…One study suggested that over-rotating in rotational acetabular osteotomy may lead to anterior bony impingement and posterior instability with resultant osteoarthritic progression, further highlighting the pitfalls of neglecting this area. 20 Education is possible in this regard, with 1 study demonstrating satisfactory postoperative clinical outcomes when comparing trainees to instructors for a similar intervention. 21 While this study indicates that rotation is a teachable skill, it called for more effort into education on the subject to prevent complications.…”

“…This indicates that angular estimation as a surgical skill is not just relevant to 1 procedure but a tool that can present helpfully in a variety of different cases, supporting our efforts to improve angle estimation among a surgical cohort. One study suggested that over-rotating in rotational acetabular osteotomy may lead to anterior bony impingement and posterior instability with resultant osteoarthritic progression, further highlighting the pitfalls of neglecting this area 20 …”