Introduction: Total hip arthroplasty preformed with the use of minimal incision surgery has received tremendous attention recently. Various surgical approaches have been introduced to minimize surgical trauma to the soft tissues. The mini invasive Modified Watson-Jones approach have been selected to decrease the perioperative complications associated with other mini invasive approaches that has been described.

The anterolateral mini incision is a new innovative approach using the intramuscular plan between the gluteus medius and the tensor fascia lata. This intermuscular interval through a small incision provides good exposure and preserves muscle integrity. Moreover, preserving the muscle integrity provides a very stable joint after implantation such that no restrictions is giving to the patient during the rehabilitation period.

Materials and Methods: Between July 2004 to September 2005, we used this approach on 60 sequential patients. Fifty patients were enrolled in this prospective study. Patients were evaluated preoperatively, immediately postoperatively, and at 3-month and 6 month follow-up according to operating time, intraoperative blood loss, subcutaneous drains blood loss, post op pain control drugs requirements, short form 36 patient questionnaire (SF-36) scores and the Harris Hip Score (HHS). 4 patients had previous THA on the contralteral side.

Results: The average operation time was 137min (range 90–200min), there were no dislocations, the mean post operation blood transfusion requirements was 1.64, the mean subcutaneous drains blood loss was 241.9ml (range 20–620ml), there was significant improvement in function, pain, SF-36 and Harris Hip Score (HHS) at the 3-month and 6-month follow-up examination. The average length of the incision was under 12cm. We had one reoperation due to deep infection. All four patients with bilateral THA preferred their last operation due to lack of post operative restrictions and due to shorter recovery of muscle strength.

Conclusion: We think that using mini invasive Modified Watson-Jones approach in total hip replacement surgeries is a preferable option. There are several advantages of using this approach compared with the more traditional techniques. Such a technique should help reduce morbidity and complication rates for those patients undergoing a total hip replacement.