Abstract
[Introduction]
Total hip arthroplasty (THA) markedly improves pain, gait, and activities of daily living for most patients with osteoarthritis. However, pelvic osteotomy has been recommended for young and active patients with hip dysplasia, because THA in that population is associated with high rates of revision THA. The rotational acetabular osteotomy (RAO) of Ninomiya and Tagawa, and the eccentric rotational acetabular osteotomy of Hasegawa for hip dysplasia reportedly are successful in young and active patients. However, even after the surgery of RAO, osteoarthritis developed in some cases and leaded to the conversion to THA. The differences of bone quality of acetabulum have been reported between at the surgery of THA after RAO and at the surgery of primary THA. We should not discuss the results of these two THA equally. The purpose of this study is to report the results of THA after RAO.
[Patients and Methods]
We retrospectively reviewed 33 patients (37 hips) treated by total hip arthroplasty after rotational acetabular osteotomy between 1992 and 2012. Five cases were performed RAO with valgus osteotomy. At the time of THA surgery, the overall mean age of the patients was 57.5 years (range, 39–72 years). The average of follow-up period was 7.0 years (range, 8–258 months). One surgeon (TT) evaluated the hips clinically using the Japanese Orthopaedics Association (JOA) score. The radiographic measurements were performed by the other physician (JY) blinded to the clinical scores. Radiographical examination was performed using AP X-ray. We evaluated the presence of osteolysis and loosening of the implants. We evaluated the stability of stem implants using Engh classification and of cup implants using Hodgkinson classification.
[Results]
The cases of this study were converted to THA in an average 17.2 years after the surgery of RAO. JOA score was 55.7 points before THA and 86.7 points at the final follow-up. Osteolysis were found in five cases. Thirty-three cases showed good implant stability, but four cases showed fibrous union between cup and acetabulum. Three cases were converted to the revision THA due to fibrous union. All revision cases were acetabular side.
[Discussion]
There were no reports about results of THA after RAO. Osteotomy should be considered for young patients because of the high rates of revision THA needed owing to prolongation of the average lifespan. McAuley et al reported the results of THA in patients 50 years and younger patients. They described the survival rates for femoral and acetabular components, using any revision as the end point, were 89% at 10-year followup and 60% at 15-year followup. Osteosclerosis of the acetabular roof bone should be careful in the case of THA after RAO. The cancellous bone could hardly be founded, even if the enough reaming was performed. Osteosclerosis may cause the difficulty in ingrowth of new bone into the implant, and lead to fibrous union between the acetabular roof bone and the implant. These two revision cases showed fibrous union before their THA. Primary fixation is very important in the case of THA after RAO.
Primary fixation is very important in the case of THA after the RAO.
