Is a short stem suitable for patients with hip dysplasia? A report on technical problems encountered during femoral reconstruction.

INTRODUCTION: A wide variety of stems have been used for the treatment of osteoarthritis secondary to advanced hip dysplasia. Since evidence for using short stems in dysplastic hips is limited, we planned to analyse the technical problems encountered when reconstructing the proximal femur of patients with osteoarthritis secondary to congenital dysplasia of the hip treated with total hip arthroplasty (THA) using a type 2B short stem.

METHODS: We prospectively analysed 17 patients (22 hips) treated with primary THA performed with a single-branded short uncemented stem with metaphyseal fixation (MiniHip™; Corin). We excluded cases in which other type of stems were used, or in which retrospective data was only available. Mean follow-up was 41.22 months (minimum 24). We analysed clinical outcome using the modified Harris Hip Score (mHHS) and pain using the visual analogue scale (VAS). Radiographs were examined in order to determine causes of complications and revision surgery.

RESULTS: All patients showed statistically significant improvement when preoperative and postoperative values for mHHS (54.19 vs. 94.57; p = 0.0001) and for pain VAS (8.71 vs. 0.71; p = 0.0003) were compared. No cases of thigh pain, instability or infection were found. 1 case of acetabular cup loosening and 1 case of periprosthetic fracture were diagnosed at 8 months and 45 days, respectively. Overall survival was 84.7% at 5 years (CI 95%, 64.4-105.3) with revision for any reason as an end point. When stem performance was separately evaluated, it showed a survival rate of 100% at 5 years with revision for aseptic loosening as an end point.

CONCLUSIONS: THA with a type 2B short stem for the treatment of dysplastic osteoarthritis showed very few technical intraoperative problems, being a useful alternative for femoral reconstruction.