Complications of Exposures for Total Hip Arthroplasty


Total hip arthroplasty (THA) has evolved significantly since the development of Charnley’s low-fraction arthroplasty in the 1950s and is now one of the most common surgical interventions. , Excellent results have been described with multiple approaches, including the posterior, direct lateral, anterolateral, and direct anterior approaches. While complications can occur irrespective of approach, certain complications have been associated with each approach, albeit sometimes for historical reasons. This chapter describes selected complications as they relate to particular approaches. Further details are described in their respective chapters.

Posterior Approach

Intraoperative Complications

Sciatic Nerve Injury

Neurologic injury after primary THA is rare, occurring at rates between 0.1% to 1.9%. Of these injuries, sciatic nerve palsy is the most common nerve injury after THA. It most often affects the peroneal division, resulting in a clinical presentation of foot drop. , The posterior approach is one risk factor, along with hip dysplasia, excessive limb lengthening, revision surgery, and lumbar spine disease. The sciatic nerve may be at higher risk during the posterior approach secondary to its proximity to the surgical field. The peroneal division of the sciatic nerve is lateral to the tibial division; thus, it may be more vulnerable to compression by deep retractors during a posterior approach. Other less-common causes of sciatic nerve injury include hematoma formation (most commonly in patients on anticoagulation medication), polymethyl methacrylate (PMMA)-induced thermal damage, neural impingement from extruded and hardened PMMA, as well as intraoperative neural laceration by scalpel, reaming, or wires or cables.

Limb positioning appears to have a role in sciatic nerve palsy. Shiramizu et al. used interoperative motor evoked potentials (MEPs) to monitor the sciatic nerve during the dislocation portion of 23 posterolateral approach THAs. Although no patients experienced nerve palsy afterwards, the authors observed significantly increased distal motor latencies in all positions other than 60 degrees of hip flexion and 60 degrees of internal rotation. Satcher et al. reported the results of monitoring the sciatic nerve via MEPs and electromyography (EMG) during 27 posterolateral revision THAs. The authors found that significant electrical events occurred most commonly during acetabular reconstruction and recommended avoiding hip flexion during posterior acetabular retraction.

Surgical intervention may be considered for readily identifiable causes of neurologic compromise, including hematoma formation, significant limb lengthening, cement extrusion, or the possibility of damage by knife or suture. , , , Additionally, the presence of pain in the distribution of the sciatic nerve signifies a continuing insult to the nerve and should prompt urgent exploration. Surgeons may reduce injury to the sciatic nerve by placing the posterior acetabular retractor within the hip capsule with the operative limb in extension to allow the nerve to displace posteriorly. Surgeons should exercise caution when placing posteroinferior acetabular screws in a revision setting. During all cases, the surgeon should be attentive to retractor placement, avoid excessive traction during hip dislocation, avoid exploration of the nerve, and avoid prolonged rotation of the limb during femoral exposure or hip flexion during acetabular exposure.

Postoperative Complications


The posterior approach for THA has historically been associated with higher rates of dislocation compared with other approaches, up to 13% in some series. The inherent risk is likely secondary to violation of the short external rotator muscles and of the weaker ischiofemoral ligament of the posterior capsule. However, the posterior approach has been refined since its initial description. Modern techniques, including larger-diameter heads and posterior capsular repair, have reduced dislocation rates to be comparable to other approaches in recent years. Publications by Pellicci et al. and Mead described posterior capsular repair, reducing dislocation rates below 1%. , A 2002 systematic review of 13,203 primary THAs found a dislocation rate of 3.95% without posterior soft-tissue repair in comparison to 2.03% with posterior repair.

During the initial approach, dissection through the short external rotator muscles should be undertaken with care. In addition to the conjoined tendon of the gemelli and obturator internus, the piriformis or quadratus femoris or both are released. Some surgeons choose to release the tendons separately from the capsule, while others release both as a “capsuloligamentous sleeve.” All tendons and capsules should be released directly off the posterior edge of the femur in order to allow as much soft tissue as possible for repair. Tagging sutures may be used to assist in capsular mobilization as needed. For the posterior soft-tissue repair, heavy absorbable or nonabsorbable sutures are passed through the posterior capsule and tendons. The sutures are then passed through the posterior trochanteric ridge of the femur via drill holes and tied down over the femur.

Though most studies report good rates of success, there have been reports of high rates of posterior instability, even after posterior soft-tissue repair. , To address this concern, Kim et al. developed a modification of the posterior approach for THA involving preservation of the piriformis, superior gemelli, and obturator internus while releasing the inferior gemelli and obturator externus. The posterior capsule is exposed by retracting the obturator internus proximally and quadratus femoris distally with blunt retractors. In their retrospective review of 670 hips 1 year after posterior approach THA, the authors found zero dislocations when the short external rotator (SER) muscles were not disrupted, as compared with a 3.9% rate of dislocation with posterior repair and a 5.3% rate of dislocation when the SERs were excised ( Fig. 17.1 ).

Fig. 17.1

Technique of a right total hip arthroplasty via a posterior approach with preservation of the piriformis, superior gemelli, and obturator internus. The obturator internus (OI), superior gemelli (SG), and piriformis (P) are retracted proximally with a Hohmann retractor ( arrow ), and the quadratus femoris muscle is retracted inferiorly to expose the posterior capsule (PC). GM, Gluteus medius; Rt. Gt, right greater trochanter.

From Kim YS, Kwon SY, Sun DH, Han SK, Maloney WJ. Modified posterior approach to total hip arthroplasty to enhance joint stability. Clin Orthop Relat Re s. 2008;466[2]:294–299.

Transgluteal Approaches: Anterolateral and Direct Lateral

The anterolateral and direct lateral approaches both split or release the gluteus medius and gluteus minimus, elevating the deep tissues anteriorly while preserving a posterior soft-tissue sleeve. The anterolateral, or Watson-Jones approach, spares the vastus lateralis. Partially releasing the abductors—the direct lateral, or Hardinge approach—elevates an anterior piece of vastus lateralis in continuity with the anterior aspect of the gluteus medius.

Intraoperative Complications

Abductor Weakness

Abductor weakness and Trendelenburg limp are known complications of transgluteal approaches to the hip secondary to either superior gluteal nerve (SGN) injury or failure of repair of the musculotendinous unit to the greater trochanter. This complication has ranged between 4% and 20% in some series. , It should be noted that approximately 20% to 25% of patients experience abductor degeneration prior to surgery, which may be exacerbated by an approach that splits these muscles. The superior gluteal nerve is at risk secondary to its proximity to the dissection through the gluteus medius in the direct lateral approach. Some degree of SGN dysfunction has been reported in 2.2% to 42.5% of patients after direct lateral THA. Injury typically leads to temporary abductor dysfunction but may become permanent in rare cases.

Postoperative abductor weakness may be minimized by careful handling of the abductor muscles. In a direct lateral approach, the gluteus medius split should not extend greater than 5 cm proximal to the insertion at the tip of the trochanter to avoid injury to the superior gluteal nerve. In both the anterolateral and direct lateral approaches, careful repair of the abductor musculature to the femur using nonabsorbable suture may facilitate tendinous healing. Modifications of the anterolateral approach without incision or reflection of the gluteal muscles have been described, obviating the need for repair and possibly leading to less abductor dysfunction. However, these approaches may require careful release of the capsule or short external rotator musculature for adequate femoral mobilization to avoid femur fracture.

Postoperative Complications

Heterotopic Ossification

Heterotopic ossification (HO) may occur after any approach for THA, occurring in up to 90% of patients. Though most cases are asymptomatic, between 3% and 10% of patients may experience persistent pain, swelling, and limited range of motion. While prospective comparative studies are limited, HO after direct lateral and anterolateral THA has been reported at rates higher than other approaches in some series. However, this HO tends to be mild and rarely limits functional outcomes. , , One purported reason for a higher incidence of HO after transgluteal approaches is the muscular damage that occurs from the gluteal split and extensive dissection of the anterior soft-tissue envelope from the femur. Additional intraoperative factors contributing to HO include bone debris, hematoma formation, and cementless components. , Higher-risk factors include male gender, bilateral arthritis, ankylosing spondylitis, diffuse idiopathic hyperostosis, and prior HO formation. ,

HO typically becomes visible on radiographs around 3 to 4 weeks postoperatively but may take up to 1 to 2 years for maturation. The Brooker classification is the most widely used for grading HO, consisting of the following: Class I, islands of bone; Class II, bone spurs from the pelvis and proximal femur separated by at least 1 cm; Class III, bone spurs from the pelvis and proximal femur separated by less than 1 cm; and Class IV, ankylosis of the proximal femur to the pelvis. While Classes I and II are rarely symptomatic, Classes III and IV may cause pain and functional limitations.

Prophylaxis may be considered for higher-risk patients. A common regimen includes external beam radiation therapy at a dosage of 7 to 8 Gy administered between 4 hours before or up to 72 hours after surgery. , Several nonsteroidal antiinflammatory drugs (NSAIDs) have been studied for HO prophylaxis as well, with indomethacin the most studied. Multiple dosing regimens have been shown to be efficacious, including 25 mg three times daily for 7, 10, or 14 days. However, a stronger dose of 50 mg three times daily was found to be ineffective.

In the rare patients with symptomatic mature HO, surgical excision is the only intervention that may eradicate it. The surgeon should delay resection until at least 6 months after the index surgery in order to allow for maturation and development of a fibrous capsule. Maturation may be confirmed with decreased activity on bone scan and normal serum alkaline phosphatase levels. Preoperative radiographic Judet views and computed tomography may be helpful to define the mass and identify displaced soft-tissue structures. While HO typically does not invade them, it may encircle key peripheral nerves and vasculature. Surgical excision must be undertaken with care and there must be meticulous handling of soft tissues in order to minimize muscle necrosis and hematoma, which could form recurrent HO. The original surgical approach is typically the most optimal, though a trochanteric osteotomy may prove necessary. Care should be taken to protect nearby neurovascular structures, such as the sciatic nerve, prior to beginning bony excision. Sharp dissection should be used to remove ectopic bone from soft tissues. An osteotome can be used gently to define the plane between HO and the true cortex; the true cortex will appear as a denser, tougher layer of bone. Intraoperative fluoroscopy should be used to confirm excision location and completeness. If range of motion remains limited after HO removal, the surgeon should consider partial or complete capsulectomy. Perioperative prophylaxis should accompany the surgical excision, as recurrence is almost certain without it ( Fig. 17.2 ).

Fig. 17.2

Preoperative (A) and postoperative (B) radiographs of a patient who developed symptomatic heterotopic ossification after total hip arthroplasty and subsequently underwent excision.

Courtesy of Zachary Post, MD

Direct Anterior Approach

Intraoperative Complications

Neurovascular Injuries

The lateral femoral cutaneous nerve (LFCN) may be injured during the superficial direct anterior (DA) approach due to iatrogenic laceration, stretch, or compression. The true incidence is unknown, as the current literature ranges from 3.37% to 81% at long-term follow-up, though symptoms tend to be paresthesias as opposed to dense numbness, and pain and functional outcome scores do not appear to be affected. The LFCN lies on the fascia in the interval between the tensor fascia lata (TFL) and sartorius. In order to minimize injury, the fascial incision should be placed overlying the TFL muscle instead of directly over the interval, a modification first described by Letournel in 1980. Surgeons should also consider a more lateral incision, avoid medial dissection in the subcutaneous fat pad, and avoid rigorous retraction of the rectus femoris.

A rare but catastrophic event, damage to the femoral neurovascular bundle, may occur if dissection proceeds through the improper interval during the initial approach or through careless retractor placement during reaming. A series of 17,350 patients had a 0.40% rate of injury to the femoral nerve. The surgeon may avoid dissection in the improper plane initially by identifying four signs of the tensor fascia lata. (1) The fascia should be translucent as opposed to the white fascia overlying the sartorius. (2) The muscle fibers should course laterally as opposed to the medially directed fibers of the sartorius. (3) Perforating vessels may be observed at the lateral aspect of the TFL fascia. (4) Once the fascia is incised, it should easily separate from the TFL with blunt finger dissection. Lack of any of these four signs should prompt the surgeon to pause and reassess anatomic landmarks before proceeding.

Femoral neurovascular injury may also occur secondary to aberrant acetabular retractor placement, as the bundle lies anterior and medial to the acetabulum. A cadaveric study found that the femoral nerve was located 17 mm from the anterior aspect of the acetabulum. Surgeons may avoid inadvertent injury by placing anterior acetabular retractors more proximally, as there is more muscle proximally than distally, and refrain from placing the retractor too far medially over the anterior inferior acetabulum , ( Fig. 17.3 ). The surgeon should also consider elevating the limb when placing an anterior acetabular retractor prior to reaming, thus allowing better visualization and relaxing the neurovascular bundle.

Fig. 17.3

The femoral vessels in relation to retractor placement in direct anterior total hip arthroplasty. The common femoral vessels lie anterior and medial to the hip capsule; retractors must be placed with care in order to avoid damage.

From Klein G, Sporer S. Neurovascular injuries: prevention, diagnosis, and treatment. In: Berry D, ed. Surgery of the Hip. 2nd ed. Saunders; 2000: 1281–1293.


Intraoperative femur fracture may occur during the DA approach done either with or without a traction table. Exposing the femur for broaching is one of the most challenging aspects of the DA approach, and improper access can lead to cortical perforation, either lateral (due to varus malposition) or posterior (due to incomplete posterior release). , Most intraoperative femur fractures occur at the level of the calcar, while perforations are more likely to be posterolateral. Incomplete femoral exposure prior to elevation of the proximal femur may also contribute to greater trochanter fracture.

It should be noted that intraoperative fracture seems to be closely related to the learning curve, with some studies reporting femur fracture only in the initial cases. , Masonis et al. reported 3 intraoperative calcar fractures in their first 62 DA THAs, but zero in the following 238. Additionally, DA THA performed on a traction table has been associated with intraoperative ankle fractures, which may be minimized by rotating the limb by the knee or tibia instead of the foot when possible. Thaler et al. describe a technique of femoral exposure for periprosthetic femur fracture using the DA approach. The incision may be extended proximally from its standard location to the anterior superior iliac spine (ASIS) and distally moving laterally and posteriorly in a “lazy-S” shape ( Fig. 17.4 ). The TFL may be released to allow for straight access to the femoral canal in order to place a long revision stem if needed. The fascia between the vastus lateralis and the rectus femoris is split distally. The IT band is gently pulled laterally away from the vastus lateralis while internally rotating the leg in order to expose the vastus lateralis to its posterior border. The fascia at the posterior aspect of the vastus lateralis may be released and the muscle retracted medially, or the vastus lateralis may be split as per surgeon preference. Perforating vessels posterior to the vastus lateralis should be cauterized as they are encountered ( Fig. 17.5 ).

Jun 18, 2022 | Posted by in ORTHOPEDIC | Comments Off on Complications of Exposures for Total Hip Arthroplasty
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