Review: posterior soft tissue repair in primary total hip arthroplasty.

IntroductionThe posterior approach is the most common approach usedin the United States. Its main advantages include (1) lessextensive tissue dissection, (2) better visualization of theacetabulum, (3) lower incidence of heterotopic boneformation, and (4) preservation of the abductor mechanism.Historically, the posterior approach in primary total hiparthroplasty (THA) was associated with an increased riskof postoperative dislocation compared to the anterolateralor the transtrochanteric approach [1–3]. The senior author(P.M.P.) has described a posterior soft tissue repairreattaching the short external rotators and the posteriorcapsule to the greater trochanter. This repair has subse-quently resulted in a signiﬁcant reduction of the risk ofpostoperative dislocation [4]. The current review describesthe surgical technique used by the senior author anddiscusses alternative techniques, biomechanical founda-tions, and the clinical outcome of patients undergoingprimary THA thorough a posterior approach with softtissue repair.Surgical techniqueThe patient is positioned in the lateral decubitus positionfor a standard posterior approach. Through a straightposterior incision, the fascia lata and the gluteus maximusmuscle are identiﬁed. It is the philosophy of the seniorauthor (P.M.P.) to use an adequate incision length becausea meticulous repair will require good exposure. Currentlythe average incision length is about 6 in.The fascia lata is incised and the gluteus maximus isﬁnger-split along its ﬁbers. A Charnley retractor is insertedto improve visualization of the posterior capsule and shortexternal rotators. Using electrocautery, the posterior fattissue and remnants of the bursa are divided, therebypreserving a layer of tissue that later can be closed over theshort external rotators. Proximally, the posterior boarder ofthe gluteus medius, and, distally, the proximal boarder ofthe quadratus femoris muscle are identiﬁed. The piriformistendon is palpated and a thin, bent Hohmann retractor isinserted over the tendon between the gluteus medius andminimus to expose the short external rotators (Fig. 1).Distally, an Aufranc retractor is inserted between thequadratus femoris muscle and the distal part of theposterior capsule. Successively the hip is positioned ininternal rotation to improve the access to the insertion ofthe piriformis and conjoined tendon. Considering that bothtendons are inserted in the piriformis fossa further anteriorthan is generally expected, it is important to release thetendon as close to its anatomic position as possible. Thiswill preserve maximum tendon length for a later tension-free repair. At its anatomic insertion the piriformis andconjoined tendon (common insertion of inferior gemellus,superior gemellus, and obturator internus muscle) willmerge to form a single wide tendon belly. As long as twoseparate tendons are released, it is likely that the tendonwas cut far away from its insertion site in the piriformisfossa. As soon as the tendon is released, two no. 2Ethibond sutures are looped through the short externalrotator tendons twice, and the tendons are pulled posteriorto expose the posterior capsule (Fig. 2). Then, the posteriorboarder of the gluteus minimus muscle is identiﬁed and aperiosteal elevator is slit between the muscle and theposterior capsule. As soon as the gluteus minimus iselevated off the posterior capsule, the thin bent Hohmannretractor is repositioned underneath it, and the posteriorcapsule is incised. Using an electrocautery, the capsuleincision is started at the 1o’clock position and descendsanteriorly toward the greater troachanter. It is important tostart the incision proximally because this part of the