Anterolateral-Supine (AL-S) Approach

There are four major total hip arthroplasty (THA) entry methods: anterior, anterolateral, lateral, and posterior. Since Crockett et al. proposed minimally invasive THA (MIS-THA) in 1998, many attempts have been made to reduce the physical and social burden on patients with osteoarthritis of the hip [1]. THA using minimally invasive procedures has been widely used in Japan, where dysplastic hips are common. MIS-THA using the anterolateral-supine (AL-S) approach (the modified Watson-Jones approach), which was reported by Pflüger et al. in 2007 [2], has become more common in Japanese hip arthroplasty registries in recent years (Figs. 52.1 and 52.2). The AL approach is an intermuscular approach that has been widely used to preserve not only the gluteus medius muscle but also the external rotator muscles, tensor fascia femoris, and posterior capsule.