Short-term outcomes of using cup-cage for revision hip arthroplasty in severe acetabular bone deficiency

Abstract

Objective To investigate the short-term outcomes after revision hip arthroplasty for severe acetabular bone deficiency by cup-cage. Methods We retrospectively analyzed 16 patients (16 hips) with Paprosky type ⅢB acetabular bone deficiency, who received cup-cage from October 2013 to May 2016. There were 6 males and 10 females, with an average age of 62.6 years (range 40-84 years). All but one patient were with pelvic discontinuity. The reason for revision was aseptic loosening for 14 patients and periprosthetic joint infection for 2. Eleven patients underwent surgery via Trabecular Metal Acetabular Revision System (cup+cage), 2 via Trabecular Metal cup and AR cage, and 3 via R3 cup and AR cage. During the follow-up, Harris hip score was recorded to evaluate the clinical efficacy, and X-rays were performed to identify the signs of loosening and changes in rotation center position. Results The mean follow-up was 18.7 months (range 6-36 months). The height of rotation center was decreased from 42.00±12.18 mm preoperatively to 22.75±8.44 mm postoperatively, whereas the horizontal distance of the rotation center was 26.81±7.61 mm preoperatively and 32.50±6.51 mm postoperatively (t=8.249, P<0.001; t=-4.786, P<0.001). The height of the rotation center was slightly higher than that of the contralateral side postoperatively (t=-3.478, P=0.003), whereas the difference in the horizontal distance of the rotation center between the two groups was not statistically significant (t=1.235, P=0.236). The Harris hip score was improved from 45.63±11.68 preoperatively to 75.78±9.12 postoperatively (t=-12.157, P<0.001). During the follow-up, one dislocation occurred at 5 days postoperatively and closed reduction was conducted under anesthesia. There was no blood vessel injury, nerve injury, wound complication and periprosthetic joint infection. No recurrence of infection occurred in 2 patients who received revision hip arthroplasty for periprosthetic joint infection. Conclusion Revision hip arthroplasty for PaproskyⅢB acetabular bone deficiency by cup-cage can achieve good primary stability and reconstruct the rotation center, especially for patient with pelvic discontinuity. Key words: Arthroplasty, replacement, hip; Reoperation; Acetabulum