Abstract
Purpose
The purpose of the present study is to assess 5–10 years' follow-up results after acetabular impaction bone grafting (IBG) in primary cemented total hip arthroplasty (THA) for cases with acetabular bone defect.
Patients and methods
We performed 36 primary cemented THA with acetabular IBG in 33 patients between November 2004 and May 2009. As one patient died due to unrelated disease at 6 months after the surgery, 35 hips of 32 patients were included in this study. The average age at the surgery was 62.4 years, and the average follow-up period was 7.9 years (5–10 years). Diagnoses were osteoarthritis due to acetabular dysplasia in 28 hips (26 patients), Rheumatoid arthritis (RA) in 4 hips (3 patients), rapidly destructive coxopathy (RDC) in 1 hip (1 patient), idiopathic acetabular protrusion in 1 hip (1 patient), and acromegaly in 1 hip (1 patient).
For clinical assessment, the Merle d'Aubigné and Postel hip score was assessed and degree of post-operative improvement was classified according to their method as very great improvement, great improvement, fair improvement, and failure. Perioperative complications were also recorded. Acetabular bone defects were assessed at the surgery and categorized using AAOS acetabular bone defect classification system.
For radiological assessment, anteroposterior radiographs of the bilateral hip joints were analyzed preoperatively and post-operatively. Radiolucent lines (RLL) of more than 2 mm around the acetabular components were assessed using the DeLee and Charnley zone classification. Acetabular component loosening was assessed according to the Hodgkinson et al. classification system, and type 3 (complete demarcation line) and type 4 (migration) were classified as “loosening”.
Results
The mean Merle d'Aubigné and Postel hip score improved from 9.8 points before the operation to 15.9 points at the final follow-up. Degree of post-operative improvement was assessed as “very great” in 11 hips, “great” in 23 hips and “fair” in 1 hip. Dislocation, DVT, and infection were recorded in 1 hip, 1 hip, and 1 hip, respectively. Re-operation was performed for the acute infection (without loosening) case at 5.3 years after the primary THA.
Acetabular bone defects were classified as segmental defect (AAOS type I) in 29 hips, cavitary defect (AAOS type II) in 3 hips and combined segmental and cavitary defect (AAOS type III) in 3 hips. Metal meshes were used for segmental defects of 29 AAOS type I hips and 2 AAOS type III hips, and for medial wall defect of 1 AAOS III hip.
On radiographic assessment, no metal device breakage was detected during the follow-up period. There were no clear lines around the cup and all cups were assessed as stable at the final follow-up.
Conclusion
Acetabular impaction bone grafting in primary cemented THA is technically demanding procedure. However, postoperative functional improvement is remarkable and stable radiographic findings were achievable independent from original diagnoses. This procedure is one of useful options to restore acetabular bone deficiency in cemented primary THA for cases with acetabular bone defect.
