Short stem hip arthroplasty via the minimally invasive direct anterior approach.

Abstract

Tissue-sparing, minimally invasive hip arthroplasty via the direct anterior approach (DAA) using apartially neck-preserving, calcar-guided short stem. Primary and secondary osteoarthritis of the hip due to developmental dysplasia, femoroacetabular impingement, femoral head necrosis or trauma sequelae. Severe osteoporosis, active infection, American Society of Anesthesiologists (ASA) > III, large metaphyseal bone defects, severe metaphyseal deformities, Dorr typeC femur. Supine position on astandard operating table without extension device. Classic DAA skin incision or bikini incision distal to the inguinal fold. Blunt dissection entering the Hueter interval. Capsulotomy with capsule preservation or partial capsulectomy. Intraoperatively, it is crucial to adhere to the preoperatively planned angle and height of the femoral neck osteotomy. During femoral head removal and acetabular preparation, care must be taken to avoid iatrogenic damage to the remaining neck. After cup positioning, femoral access is achieved by release of superior capsular structures. During opening of the medullary canal and broaching, femoral torsion and axis have to be taken into account for correct rotational and axial alignment. Femoral broaches are inserted in an ascending series of sizes until the last broach is firmly lodged and is in direct contact with the antero-medial femoral neck cortex. Fluoroscopic control in two planes to check for femoral anatomic and overall offset and assess whether the implant is adequately seated with cortical support at the calcar, the distal lateral and the dorsal cortex. Implantation of the definitive implants, local infiltration analgesia and wound closure. Between 1/2011 and 12/2016 60patients (24female, 36male; mean age 44years) were treated with apartially neck-preserving short stem via the described approach. Seven patients underwent abi-lateral procedure. Thus, 67procedures were analysed in this retrospective cohort study. Mean follow-up was 70months (range 28-93). The median Harris Hip Score was48 (range 11-88) preoperatively and98 (range 80-100) postoperatively. The minimally invasive implantation of apartially neck-preserving stem via DAA provides asafe technique with good to excellent clinical results in the mid-term.