90 patients with unilateral primary hip osteoarthritis scheduled to undergo cementless total hip arthroplasty were randomized to receive the procedure through a minimally invasive or conventional open anterolateral Watson-Jones technique. The purpose of this study was to compare both techniques in terms of blood loss, pain, and function over four years. The results of this trial suggest that the minimally invasive approach can provide an early reduction in postoperative pain relief; however, it appears that there are no significant mid-term clinical and functional benefits for patients undergoing a MIS producer.