Total hip arthroplasty through the mini-incision (Micro-hip) approach versus the standard transgluteal (Bauer) approach: a prospective, randomised study.

Abstract

To compare outcome after total hip arthroplasty (THA) through the mini-incision approach versus the standard transgluteal approach. 80 women and 63 men aged 33 to 89 (mean, 62) years with primary osteoarthritis of the hip were randomised to undergo unilateral THA through a mini-incision approach (Micro-hip, n=55) or standard, lateral, transgluteal approach (Bauer, n=88). Levels of haemoglobin, haematocrit, serum creatine kinase, and C-reactive protein, length of hospital stay, mobilisation, and any complication were recorded. Visual analogue scale (VAS) for pain was assessed. Hip function was assessed using the Harris Hip Score and the Oxford Hip Score, whereas general health was assessed using the EQ-5D general health questionnaire. The cup inclination and varus/valgus of the stem position were measured using a goniometer. The Micro-hip group achieved a significantly lower mean incision length (9.3 vs. 13.4 cm, p<0.001), mean surgical time (60 vs. 68 minutes, p=0.021), mean reduction in haemoglobin level (2.1 vs. 2.8 g/dl, p<0.001), and mean VAS for pain from hour 6 to day 6 (all p<0.05). One patient in the Micro-hip group developed early aseptic loosening of the cup and underwent revision surgery at month 4. Three patients in the Bauer group and one patient in the Micro-hip group sustained intra-operative nondisplaced fractures of the proximal femur, which were fixed with cerclages. Two patients in the Microhip group developed deep vein thrombosis during week 1. THA through the Micro-hip approach achieved faster pain relief.