Anterior total hip arthroplasty using a metaphyseal bone-sparing stem: component alignment and early complications.
BACKGROUND
Limited-incision total hip arthroplasty (THA) preserves hip abductors, posterior capsule, and external rotators potentially diminishing dislocation risk. However, potential complications also exist, such as component malposition. Specific implants have been manufactured that enhance compatibility with this technique, while preserving metaphyseal bone; however, little data exists documenting early complications and component position. The purpose was to evaluate primary THA using a curved, bone-sparing stem inserted through the anterior approach with respect to component alignment and early complications.


METHODS
In a retrospective analysis of 108 cases, the surgical technique was outlined and the occurrence of intraoperative fractures, postoperative dislocations, infection, and limb length inequality was determined. Femoral stem and acetabular cup alignment was quantified using the initial postoperative radiographs. Patient follow-up averaged 12.9 (range 2 to 36) months.


RESULTS
There were eight (7.4 %) complications requiring revision surgery in three (2.8 %) patients with three (2.8 %) infections and three (2.8 %) dislocations. Intraoperative complications included one calcar fracture above the lesser trochanter. Leg length inequality >5 mm was present in three (2.8 %) patients. Radiographic analysis showed that femoral neutral alignment was achieved in 95 hips (88.0 %). All femoral stems demonstrated satisfactory fit and fill and no evidence of subsidence, osteolysis, or loosening. An average abduction angle of 44.8° (± 5.3) and average cup anteversion of 16.2° (± 4.2) were also noted.


CONCLUSIONS
Although the technique with this implant and approach is promising, it does not appear to offer important advantages over standard techniques. However, the findings merit further, long-term study.
Department of Orthopaedic Surgery, Saint Louis University School of Medicine, 3635 Vista Ave., Desloge Towers 7th Fl, St. Louis, MO, 63110-2539, USA. mahmed9@slu.edu.
Mohammed M
MM
Ahmed
Department of Orthopaedic Surgery, Saint Louis University School of Medicine, 3635 Vista Ave., Desloge Towers 7th Fl, St. Louis, MO, 63110-2539, USA.
Thomas J
TJ
Otto
Department of Orthopaedic Surgery, Saint Louis University School of Medicine, 3635 Vista Ave., Desloge Towers 7th Fl, St. Louis, MO, 63110-2539, USA.
Berton R
BR
Moed
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D019644:Arthroplasty, Replacement, Hip / Q000009:adverse effects / Q000295:instrumentation / Q000379:methods*; D005260:Female; D005500:Follow-Up Studies; D006621:Hip Joint / Q000000981:diagnostic imaging; D006622:Hip Prosthesis; D006801:Humans; D007870:Leg Length Inequality / Q000209:etiology; D008297:Male; D008875:Middle Aged; D011474:Prosthesis Design; D011475:Prosthesis Failure; D016459:Prosthesis-Related Infections / Q000601:surgery; D011859:Radiography; D012086:Reoperation; D012189:Retrospective Studies
Anterior approach; Bone-preserving stem; Complications; Total hip arthroplasty