Posterolateral Approach to the Hip





CASE STUDY


A 42-year-old man presented with bilateral hip pain 1 year after undergoing staged, bilateral total hip arthroplasties (THAs). The patient had his right hip replaced first, with good early results, followed 6 weeks later by a left THA. Wound healing on the left was delayed, and he underwent superficial irrigation and débridement without complication. On presentation, the patient reported a 3-month history of squeaking, pain, and limited ability to ambulate.


On physical examination, he had bilateral pain and guarding with any motion of his hips. The patient had a history of hypertension and chronic steroid use leading to osteonecrosis of the femoral heads. An anteroposterior radiograph of the pelvis revealed loosening of the bilateral acetabular components ( Fig. 49.1 ). Preoperative infection parameters were negative, including laboratory values for the erythrocyte sedimentation rate, C-reactive protein level, and synovial white blood cell count (<3000 cells/μL).




FIGURE 49.1


A, Anteroposterior radiograph of the pelvis reveals aseptic loosening and migration of the patient’s bilateral acetabular components (arrow) . B, Intraoperative photograph shows gross loosening of the acetabular component.


His original surgery was performed through a posterior approach, and he underwent staged, bilateral acetabular component revisions. Because of the squeaking, the patient’s preoperative metal ion serum levels (chromium, 38.3 ng/mL; cobalt, 24.9 ng/mL; titanium, 19.27 ng/mL), and the position of the components, a posterior approach was used for revision surgery in case a trochanteric osteotomy was required to remove the femoral stem (because of notching of the implant trunnion by the acetabular component). The patient underwent successful staged, isolated acetabular revision surgery without complication ( Fig. 49.2 ).




FIGURE 49.2


A, In the anteroposterior radiograph of the pelvis after isolated revision of the right acetabular component, notice further migration of the right acetabular component (arrow) . B, Anteroposteror radiograph of the pelvis 6 months after staged, bilateral acetabular revisions were performed.




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Clinical/Surgical Pearls





  • The posterolateral approach is the most commonly used approach for revision THA.



  • This surgical exposure can be readily extended if component removal requires a trochanteric osteotomy.



Clinical/Surgical Pitfalls





  • Common complications include formation of heterotopic ossification, sciatic nerve palsy, and dislocation.



  • If an anterior approach was used in the prior operation, if the patient has a neurologic disorder, or if there is a high risk of dislocation, an anterior or direct lateral approach should be considered.





Introduction


The posterolateral approach to the hip is commonly performed for primary and revision total hip arthroplasty (THA). For many surgeons, it is the workhorse approach, allowing access to the posterior wall of the acetabulum, the posterior column of the pelvis, and the entire femur if necessary. Less invasive surgery can be performed through the posterolateral approach, which can be converted to a more extensile exposure if needed. Trochanteric osteotomy, fixation of periprosthetic fractures, and plating of a pelvic discontinuity in revision THA can be safely performed through this approach. Proponents of the posterior approach cite the easy, versatile, and reproducible exposure that can be gained with minimal assistance. Critics of this surgical approach have concerns about dislocation, sciatic nerve injury, and limb length discrepancy.




Indications and Contraindications


A posterolateral approach to the hip is indicated for several procedures:




  • Primary THA or surface arthroplasty



  • Revision of THA with a previous posterolateral approach



  • Revision of the femoral component



  • Revision of the acetabular component



  • Plating of the posterior column



  • Fixation of a periprosthetic femoral fracture



  • Use of an extended trochanteric osteotomy (ETO)



  • Neurolysis of the sciatic nerve



Relative contraindications include the following:




  • Anterior column fractures



  • Previous anterior approach to the hip



  • Patients at high risk for dislocation (e.g., neurologic disorder, Parkinson disease, noncompliance, dementia)





Surgical Technique


A standard posterolateral approach is performed with the patient in the lateral decubitus position. Since the nineteenth century, this approach has been described in the literature by many surgeons with slight variations. Commercial hip positioners are available as table clamps or peg boards, and they are used to secure the pubis or anterior ilium and the lumbosacral spine ( Fig. 49.3 ). Due to potentially lengthy procedures in the revision situation, appropriate padding is required for the nonoperative side to minimize the risk of skin breakdown and nerve palsy. Care must be taken so that the pegs and pelvic clamps do not act as a lever arm on the femur during range-of-motion testing; they need to be covered to prevent skin abrasions and tears ( ). In a revision case in which previous incisions are present, draping is done far enough proximally to ensure adequate exposure.




FIGURE 49.3


A, Standard hip positioner attaches to the surgical table. B, The anterior arm is positioned against the pubis and the contralateral anterior superior iliac spine. C, Posteriorly, the positioner is placed against the sacrum and posterior pelvis. All bony prominences on the downside leg are well padded. D and E, A similar set-up uses a peg board–style positioner.


The surgical incision varies according to the procedure and required exposure, but it is typically made along the posterior one third of the femur with the hip in midflexion at the level of the greater trochanter and extended distally in line with the femur. The incision can be extended proximally toward the posterior superior iliac spine for exposure of the posterior column and pelvis. Distally, the approach can be extended the entire length of the thigh, curving anteriorly at the knee to expose the entire femur ( ). The versatility and ease of extension of the posterior approach is one of the reasons it is considered a workhorse approach in revision situations. Previous skin incisions should be used if possible, and large skin bridges of at least 8 cm should be preserved if a new incision is made. The rate of wound necrosis around the hip usually is small because the blood supply to the skin around the hip is bountiful.


Surgical dissection is carried down to the fascial layer overlying the gluteus maximus proximally and the iliotibial band distally. During revision surgery, it is often difficult to define anatomic layers, and care must be taken to avoid developing multiple planes, which leads to creation of a large potential dead space. In patients with a body mass index (BMI) greater than 30, it is possible to dissect too far posteriorly, because it is relatively easy to get distracted by the depth of the subcutaneous fat layer. The fascial layer is split, and the gluteus maximus muscle can be bluntly divided, coagulating vessels as necessary ( ).


Deep to the gluteus maximus muscle, a self-retaining retractor such as a Charnley retractor is placed, with care taken to ensure that the sciatic nerve is not compressed or stretched. In revision surgery, the gluteus maximus tendon often is released from its insertion on the gluteal tuberosity of the posterior femur, leaving a small cuff on the femur for repair during closure. A retractor can be placed to elevate the vastus lateralis muscle anteriorly while this release is performed. Release of the gluteus maximus assists in internal rotation of the hip in the setting of soft tissue contractures, affords greater mobilization of the femur, and decompresses the sciatic nerve distally. During release of the gluteus maximus tendon, the first perforating branch of the profundus artery is encountered as it courses from posterior to anterior, and it should be avoided or coagulated. If the femoral diaphysis needs to be exposed for fracture fixation or an osteotomy, the vastus lateralis can be lifted anteriorly from the linea aspera or split in line with its fibers, with care taken to coagulate all perforating vessels ( Fig. 49.4 ). The entire vastus lateralis can be mobilized in this manner to the level of the lateral epicondyle of the distal femur if lateral plating is required.


May 29, 2019 | Posted by in ORTHOPEDIC | Comments Off on Posterolateral Approach to the Hip
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