Our Experience with Short Stem Hip Replacement Surgery

Context- A short anatomical metaphyseal femoral stem is a desirable hip implant for bone and soft tissue preserving hip replacing surgery in young arthritic patients. Physiological loading of the proximal femur prevents stress shielding and preserves bone stock of the femur in the long run. Thus it is an ideal hip implant suited for conservative hip surgeries in active young adults with arthritic hips. Materials and methods- 50 Proxima hip replacements were performed on 41 patients with a mean age of 45 over a 3-year period (between July 2006 and September 2009). Diagnosis of hip pathologies varied from osteoarthritis secondary to avascular necrosis, rheumatoid arthritis, post-tubercular arthritis to dysplastic hips. 9 of these patients had symptomatic bilateral hip involvement and underwent bilateral hip replacement in a single sitting. All patient had a Proxima metaphyseal stem implantation( DePuy, Warsaw) with either a large diameter metal on metal or pinnacle articulation. Clinical and radiological evaluation was done at 3 months, 6 months, 1 year and then yearly thereafter. Statiscal analysis used- VAS and Harris hip score formed the basis of evaluation Results- These patients were followed up for a mean period of 49 months (Range 36-72 months). The average incision size was 14.38 cm (10-18 cm) and blood loss was 269 ml (175-450 ml). There was no peri-operative mortality or serious morbidity in any patients. One patient had an intraoperative lateral cortex crack that required only delayed rehabilitation. Five of the 41 patients (12.1 %) had complications with three recovering completely and one requiring revision of femoral stem for aseptic loosening. One patient was lost in follow-up. Harris hip score improved from 52 to 89.3 at last follow-up. Overall 95.1% (39/41) patients had an excellent outcome at last follow-up. Conclusion- We conclude that Proxima metaphyseal stem provided clinically and radiologically stable fixation through snug fit initially followed by bone in-growth and was ideally suited to satisfy the requirements of a conservative hip implant. Unfortunately, due to unknown reasons, the implant has been recently withdrawn from the market by DePuy and is no longer available for use. Key Message Conservative hip stems that preserve bone and soft tissue at the time of surgery, prevent femoral stress shielding by circumferential loading, promote positive bone remodeling and help to make revision surgeries easier are ideally suited as hip implants for young active adults with end stage hip disease requiring hip replacement surgery.