Cotyloplasty in Cementless Total Hip Arthroplasty for an Insufficient Acetabulum

Abstract

BackgroundCotyloplasty is a technique that involves making a perforation of the medial wall of a shallow acetabulum and then inserting an acetabular cup with the medial aspect of its dome beyond the Kohler line. The purpose of this study was to evaluate the results of cementless total hip arthroplasty (THA) using cotyloplasty with focusing on the amount of medial cup protrusion.MethodsSixteen hips with insufficient acetabulum in sixteen patients were treated by cementless THA using cotyloplasty. The average patient age was 47 years. The diagnoses included dysplastic hip (12) and infection sequelae (4). All the patients were followed up for at least 2 years. Clinically, the Harris hip scores were assessed and radiologically, the amount of cup protrusion, the hip center movement and cup fixation were evaluated.ResultsThe average Harris hip score improved from 57 to 94 postoperatively. The average proportion of cup surface beyond the Kohler line was 44.1% and the hip centers were medialized by an average of 23 mm. Stable fixation of the acetabular cup was achieved in all the cases except one. In this one case, migration of the cup was detected 2 weeks postoperatively and a reoperation was performed.ConclusionsUsing cotyloplasty, good coverage of the acetabular cup was obtained without a block bone graft, and the hip joint centers were medialized. However, the safety margin for the amount of protrusion should be established.

Controlled Fracture of Medial Wall Versus Structural Autograft With Bulk Femoral Head to Increase Cup Coverage by Host Bone for Total Hip Arthroplasty in Osteoarthritis Secondary to Developmental Dysplasia of Hip: a Retrospective Cohort Study

“…So, what rate of medial protrusion of the cup is the best? Dorr et al [23] recommended this rate should be less than 45% and Kim et al [24] suggested it should be within 50%-60%. Besides, according to Zha et al [8], a prospective 6-to 9-year follow-up of 43 consecutive patients using medial protrusio technique in cementless THA for DDH demonstrated that the rate of medial protrusion more than 60% had a high aseptic loosening rate in midterm.…”

“…Inclination of cup is de ned as the angle between a horizontal line joining the ischial spines and a line parallel to the opening plane of the cup [22]. Rate of cup coverage and rate of medial protrusion are measured according to the methods introduced by Dorr et al [23] and Kim et al [24]. Rate of cup coverage is de ned as the ratio of degree of cup covered by the host bone and 180°( Fig.…”

Total hip arthroplasty following failure of tantalum rod implantation for osteonecrosis of the femoral head with 5- to 10-year follow-up

“…Femoral stem osteolysis and radiolucencies were classified, as previously described by Gruen et al [13] Furthermore, the acetabular components were evaluated according to the DeLee and Charnley classification of acetabular osteolysis and radiolucencies [14]. Periprosthetic osteolysis is defined as a circular or oval area of distinct bone loss with a diameter of > 2 mm [15]. A radiolucent line between the implant and the surrounding bone, usually parallel to the implant surface.…”

Reconstruction of the Shallow Acetabulum With a Combination of Autologous Bulk and Impaction Bone Grafting Fixed by Cement

“…Total hip arthroplasty (THA) in patients with DDH is technically demanding because of the altered hip anatomy. For acetabular reconstruction, the following techniques are described: (1) cranial positioning of the acetabular component (high hip center for steep acetabuli) [17, 31]; (2) medial protrusion technique (cotyloplasty for shallow acetabuli) [8, 19]; (3) customized acetabular augments (three-dimensional printing) [4] or high-porosity sockets such as Trabecular Metal, Regenerex, or Tritanium; (4) acetabular roof reconstruction with autologous bone grafting [33]; and (5) graft augmentation by rim mesh or hooked reinforcement ring devices with impaction morselized bone grafting [1, 15, 35]. In the first three techniques, however, acetabular bone stock is not preserved and the original hip center may be displaced.…”