CAN WE USE THE DIRECT ANTERIOR APPROACH TO THE HIP IN OBESE OR VERY OLD PATIENTS? SHOULD WE?

Introduction: It has been stated that less invasive total hip arthroplasty requires patient selection to lessen complications and to promote a successful outcome. However, it is unknown if certain patients risk an increase in complications, or if unselected patients benefit from these operations. This prospective study addresses these questions. Methods: Two patient groups, from a larger series, were studied: BMI over 30 (71 patients); Age over 80 (41 patients). The average BMI was 34 (highest 46); the average age, 84 (oldest 91). A single incision direct anterior approach was used universally. At regular follow-up WOMAC, Charnley modified Merle D’Aubigne, Harris Hip Scores and x-rays were obtained. RESULT: Hip Scores showed significant improvement (p = 0.001 for each), component positioning was reproducible; length of hospital stay and return to full function were acceptable. However, compared to non-obese, younger patients having the same operation, the very elderly were less likely to go directly home (45% compared to 80% overall), the risk of medical complications was increased for these patients (4% of the obese and 6% of the elderly); and there was a disproportionately high incidence of mechanical complications (6% for the obese; 2.5% for the elderly). Discussion: These data indicate that lesser invasive hip arthroplasty using a single incision anterior approach can benefit obese and elderly patients. However, the incidence of complications may be elevated. Information derived from a selected MIS series should be considered sceptically before applying it to our practices.