The fear of high complication rates, repeated surgery and component mal positioning, especially early in the surgeon’s experience, can be an obstacle for starting a new technique like minimally invasive THR. The aim of the present investigation was to report on our learning curve of the first 100 consecutive minimally invasive total hip replacements through an anterior approach and to focus on intraoperative and postoperative complications as well as on the quality of implant positioning. In order to have a comparison, the last 100 THR performed through our previously used direct lateral approach were retrospectively evaluated. In both groups, complex acetabular and femoral reconstructions were excluded as they were performed though a digastric trochanteric osteotomy. Every change of the initial surgical plan was considered an intraoperative, every change in the rehabilitation plan considered a postoperative complication. The quality of implant positioning was evaluated in a standardized anteroposterior pelvic x-ray and a cross table lateral view at the 3 month follow-up visit and included the positioning of the cup and the stem in both views and the amount of leg-length discrepancy. In terms of age, gender, BMI, ASA-score and origin of osteoarthritis both groups differed not from each other. Intraoperative and postoperative complications were more frequent in the MIS-Group (17 versus 7) and occurred within the first 30 cases. 12 were solved during the same anesthesia and 2 during the same day without manifest disadvantage at the 3 month follow-up visit. In one case a dislocation occurred. In two patients neuralgia of the lateral cutaneous femoral nerve was successfully treated conservatively. Implant positioning and leg-length discrepancy did not differ between the two groups. Overall, starting a minimally invasive technique was associated with more frequent complications; however, if recognized and appropriately managed nearly none of them resulted in disadvantages for the patient at the 3 months follow-up visit.
