**5. Soft tissue procedures**

To optimize hip stability, attention should be drawn to the soft tissue integrity and tensioning around the hip. Approaches that utilize the lateral decubitus position require meticulous capsular repair. Critics have stated capsular repairs will ultimately fail or lead to an unnecessary increase in surgical time; however, this repair has demonstrated less blood loss, decreased dislocations, and better functional outcome scores [140, 141]. In contrast, supine approaches have not shown this increased benefit [142]. Schwartz et al. published a randomized controlled trial regarding capsular repair vs. capsulectomy utilizing the direct anterior approach noting no difference in outcomes [143]. The increased stability from the direct anterior muscle sparing approach maybe from the preservation of the short external rotators or from the fluoroscopic guidance of intraoperative implant positioning. Ultimately, the data is unclear whether capsular retention and repair is necessary for post-operative hip stability using the direct anterior approach.

Even when the femoral and acetabular components are appropriately oriented, restoration of length and offset are needed to recreate the mechanical advantage of the abductors [144]. Abductor tensioning is affected by the sizing and positioning of both the femoral and acetabular components. Poor abductor repair, failure of trochanter osteotomies, and destruction of the greater trochanter from fracture or osteolysis will adversely affect this tensioning [145]. In severe cases of abductor deficiency, soft tissue transfers may be needed to increase strength and stability of the hip joint. A transfer of the anterior ½ of the gluteus maximus to the greater trochanter has been described to increase lateral stability and to assist with Trendelenburg gait [146]. It is also possible to perform transfers such as transferring the anterior half of the gluteus maximus to the greater trochanter to increase lateral stability and to assist with issues of Trendelenburg gait [147].

Although rarely required for a primary hip arthroplasty, a greater trochanteric osteotomy is indicated to remove well fixed implants for hip revisions. Robust fixation of this osteotomy is crucial to avoid trochanteric nonunion which can result in pain, hip weakness, and hip instability [148]. In cases of abductor weakness or trochanteric nonunion, an advancement may be considered. Dennis and Lynch describe a greater trochanter advancement surgery specifically in patients who have postoperative hip weakness and instability [146].
