A new short uncemented, proximally fixed anatomic femoral implant with a prominent lateral flare: design rationals and study design of an international clinical trial

<p>Abstract</p> <p>Background</p> <p>Anatomic short femoral prostheses with a prominent lateral flare have the potential to reduce stress-shielding in the femur through a more physiological stress distribution to the proximal femur. We present the design rationale of a new short uncemented, proximally fixed anatomic femoral implant and the study design of a prospective multi-centre trial to collect long-term patient outcome and radiographic follow up data.</p> <p>Methods</p> <p>A prospective surveillance study (trial registry NCT00208555) in four European centres (UK, Italy, Spain and Germany) with a follow up period of 15 years will be executed. The recruitment target is 200 subjects, patients between the ages of 18 and 70 admitted for primary cementless unilateral THA will be included. The primary objective is to evaluate the five-year survivorship of the new cementless short stem. The secondary objectives of this investigation are to evaluate the long term survivorship and the clinical performance of the implant, the impact on the subjects health related Quality of Life and the affect of the prosthesis on bone mineral density. Peri- and postoperative complications will be registered. Clinical and radiographic evaluation of prosthesis positioning will be done post-operatively and at 3, 6, 12, 24, 60, 120 and 180 months follow up.</p> <p>Discussion</p> <p>Shortening of the distal stem can maximise bone and soft tissue conservation. New stem types have been designed to improve the limitations of traditional implants in primary THA. A new, uncemented femoral short stem is introduced in this paper. A long-term follow up study has been designed to verify stable fixation and to research into the clinical outcome. The results of this trial will be presented as soon as they become available.</p

Congenital hip dysplasia treated by total hip arthroplasty using cementless tapered stem in patients younger than 50 years old: results after 12-years follow-up

Background Congenital hip dysplasia may lead to severe acetabular and femoral abnormalities that can make total hip arthroplasty a challenging procedure. We assessed a series of patients affected by developmental hip dysplasia treated with total hip arthroplasty using cementless tapered stem and here we report the outcomes at long-term follow-up. Materials and methods Twenty-eight patients (24 women and 4 men) aged between 44 and 50 years (mean 47 years) were observed. Clinical evaluation was rated with the Harris Hip Score. Radiographic evaluation consisted in standard anteroposterior and axial view radiographs of the hip. According to Crowe’s classification, 16 hips presented dysplasia grade 1, 14 grade 2, and 4 grade 3. All patients were treated with total hip arthroplasty using a cementless tapered stem (Wagner Cone Prosthesis). Six patients were operated bilaterally, with a totally of 34 hips operated. After surgery, the patients were clinically and radiographically checked at 3, 6, and 12 months and yearly thereafter until an average follow-up of 12 years (range 10–14 years). Results Average Harris Hip Score was 56 ± 9 (range 45–69) preoperatively, 90 ± 9 (range 81–100) 12 months after surgery, and 91 ± 8 (range 83–100) at last follow-up. Radiographic evaluation demonstrated excellent osteointegration of the implants. Signs of bone resorption were present in 6 hips, nevertheless no evidence of loosening was observed and none of the implants has been revised. Conclusions Even in dysplasic femur, the tapered stem allowed adequate stability and orientation of the implant. We consider tapered stem a suitable option for total hip arthroplasty in developmental hip dysplasia, also in case of young patients, thanks to the favourable long-term results

A long-term follow-up study of the cementless THA with anatomic stem/HGPII cup with 22-mm head

The anatomic femoral component and Harris-Galante porous II (HGPII) cup were developed to provide more reliable bone ingrowth. We performed 20 cementless total hip arthroplasties (THAs) with anatomic stem/HGPII cup with 22-mm head in 14 consecutive patients, and evaluated the clinical and radiological results for a mean follow-up of 12.8 years. The all-anatomically designed stem provided excellent clinical and radiographic results. Four acetabular components underwent revision: three for fracture of the locking mechanism and wear of the polyethylene liner and one for the locking mechanism failure with dislocation of the HGPII cup. The abduction angles of the four revised acetabular components were apparently higher. The survivorship 13 years after surgery was 78%. Our findings show good long-term results using the anatomic femoral component, while the HGPII cup combined with 22-mm head seems to have poor durability due to locking mechanism failure