ABSTRACT
Objective To evaluate the results of computer-aid customized acetabular cages for patients with severe defects.Methods Twenty-three patients (8 males and 15 females) with a massive acetabular defects were involved in the present study from January 2005 to September 2014.The average age was 64.2 years (range,46-79 years).According to the American Academy of Orthopaedic Surgeons (AAOS) classification,20 had AAOS type Ⅲ defects and three had AAOS type Ⅳ defects.The customized cages were individualized to each patient's bone defects based on the rapid prototype three-dimensional printed models.The mean follow-up duration was 66.3 months (range,24-120 months).The clinical and radiographic outcomes of all patients were assessed at 6 and 12 weeks after surgery and at once yearly thereafter.Harris hip scores were assessed before surgery and at each follow-up.Postoperative radiographs were evaluated for cage position,migration,and graft incorporation.Complications and reoperations were assessed by chart review.Results The mean Harris hip score improved from 36.2±7.9 (range,20-49) to 81.8± 8.4 (range,60-96),and there is a significant difference between pre-and post-operation (t=23.23,P＜0.001).Individualized custom cages resulted in generally reliable restoration of the hip center.The difference of horizontal distance (between the center of each hip and pubic symphysis) between bilateral sides was-3.0±6.4 mm (range,-19-8 mm).The difference of vertical distance (between the center of each hip and the line connecting the inferior border of the bilateral tear drop) between bilateral sides was 0.4±2.8 mm (range,-4.5-5 mm).No re-revisions had been conducted.None of the cups showed radiographic migration,while one cage was suspected to be loose based on a circumferential 2-mm radiolucent line.Cancellous allografts appeared to be incorporated in 22 of 23 patients.One deep infection and one superficial infection were observed and were treated with irrigation,debridement,and vacuum sealing drainage.One dislocation and one suspected injury of the superior gluteal nerve also were observed and were treated conservatively.Conclusion Individualized customized cages appears to provide stable fixation and improve hip scores at short or mid-term follow-up.