In the United States, total hip arthroplasty (THA) is typically performed with the patient in the lateral decubitus position. Positioning of the morbidly obese patient can be technically challenging and may require special positioning equipment. Although the increased incidence of complications after THA in obese patients has been well documented, neurologic complications in the contralateral limb are rare. This article describes a case of a patient with impairment of the lateral femoral cutaneous nerve in the contralateral leg after THA.
A 55-year-old woman with a body mass index of 34.24 kg/m2 underwent THA in the right lateral decubitus position. Because of her body habitus, a bean-bag positioner was used. Total hip arthroplasty was performed using a direct lateral approach. Intraoperative surgical time was 2.5 hours, and total anesthesia time was 3.5 hours. A few days postoperatively, the patient began to experience burning and shooting pain in the contralateral hip, but she did not report this pain until 6 weeks postoperatively. She was treated initially with a single lidocaine injection. When this was ineffective, she was treated with topiramate (100 mg daily) and vitamin B6 (100 mg orally twice daily). The symptoms lessened markedly at 5 months and resolved completely at 9 months postoperatively.
Meralgia paresthetica is an uncommon, but known, complication of THA. To our knowledge, it has been reported only in the operative limb. This report reinforces the need for careful positioning to avoid pressure over the anterior superior iliac spine intraoperatively.
Neurologic complications after total hip arthroplasty (THA) are relatively uncommon, with a reported overall incidence of 1% to 2%.1 Such complications usually involve the operated limb and are the direct result of internal physical disturbances intraoperatively. Nerve compression injuries as a result of positioning have also been reported,2,3 usually as a result of inadequate padding of bony prominences such as the elbow or the knee intraoperatively. Peripheral nerve injuries can also result from excessively long surgeries or periods of hypoxia intraoperatively.4 This article describes a case of a moderately obese woman with osteoarthritis who underwent a THA in the lateral decubitis position and in whom meralgia parasthetica subsequently developed in the contralateral leg.
A 55-year-old woman with debilitating osteoarthritis in her left hip was initially treated nonoperatively; the regimen included celecoxib (200 mg by mouth twice daily) and a cane in the contralateral hand. The persistent pain had been symptomatic for nearly 2 years and seriously limited her activities of daily living. The patient also reported an intermittent, mild, aching pain in her right knee that had lasted for 7 months. After nonoperative interventions failed, a left THA was recommended.
Based on her height (68 in) and weight (225 lbs), her body mass index (BMI) was 34.24 kg/m2, indicating moderate obesity (BMI 30-35). Although this obesity was not extreme by BMI, it was mostly central, making it impossible to use our usual hip positioner (Universal Lateral Positioner; Innovative Medical Products, Inc, Plainville, Connecticut) for secure positioning. For such patients, we use a deflatable bean-bag positioner (Vac-Pac positioner; Olympic Medical Corp, Seattle, Washington) for secure decubitis positioning.
After the administration of spinal anesthesia, the patient was placed in the right lateral decubitus position. The inflated bean-bag positioner was adjusted to extend from 10 cm distal to the axilla to the knee. To improve patient stability, the positioner was then adjusted to hold the patient in a true decubitis position with the pelvis lateral, the right (contralateral) hip flexed 20°, and the right knee flexed 20°. The bean bag was deflated with suction to make it semi-rigid. An additional axillary role towel was placed under the lateral chest to prevent axillary compression. The right lateral malleolus and the right elbow were also padded. The left hindquarter was draped free.
The THA was performed using a modified Hardinge direct lateral approach.5 The hip was dislocated, and the femoral neck cut was made per templating. The acetabulum was sequentially reamed with hemispherical reamers. A 55-mm Converge acetabular component (Zimmer, Inc, Warsaw, Indiana) was placed. The leg was flexed and externally rotated to expose the proximal femur, and the foot was placed over the side of the table into a leg bag. The femur was then sequentially broached to accept a #5 Alloclassic stem (Zimmer, Inc). A 28-mm trial head was placed, and the hip was evaluated for leg length, offset, version between the femur and acetabulum, tissue tension, and stability. The final 28-mm head implant was placed, and the hip was closed in layers. The operation, from incision to skin closure, lasted 2.5 hours. The patient was under anesthesia for approximately 3.5 hours. There were no immediate complications.
Postoperatively, the patient was allowed to bear weight as tolerated and was mobilized on postoperative day 1. The rehabilitation regimen included weight bearing as tolerated, no abductor strengthening for 6 weeks, and dislocation precautions (no hip flexion >90°, no hip adduction past midline, use of an abductor pillow in bed) for 6 weeks. Deep venous thrombosis prophylaxis consisted of early mobilization, thromboembolic-deterrent stockings, sequential compression devices, and enteric coated aspirin (325 mg twice daily). The patient did well postoperatively, was discharged to rehabilitation 24 hours postoperatively, and was released from the hospital after an additional 48 hours.
At 6-week follow-up, the patient noted that she had experienced (but not reported) a sudden onset of pain in the contralateral hip beginning just after the THA surgery. She described the pain as burning, shooting, and stabbing and as having increased in the interim. The pain was located in the anterior thigh and radiated to the medial knee. That area was also painful to the touch.
The patient was diagnosed with meralgia paresthetica based on her description of the problem. She was injected with 10 mg of triamcinolone and 5 mL of 1% lidocaine into the thigh. One month later, the condition was unresolved, and the patient was prescribed topiramate (100 mg daily) and vitamin B6 (100 mg orally twice daily). This regimen provided some relief, and at 5 months postoperatively, the meralgia paresthetica appeared to be resolving. It had resolved completely by 9 months postoperatively.
Meralgia paresthetica is a condition most commonly associated with compression around the anterior superior iliac spine, resulting in an entrapment neuropathy or a neuroma of the lateral femoral cutaneous nerve.6,7 The lateral femoral cutaneous nerve has a highly variable local anatomy, with branches exiting the pelvis in many different locations (Figure),8,9 which may account for the highly varied cause, nature, and site of the compression, irritation, or neuropathy.8
Figure: Variations in the course and location of the lateral femoral cutaneous nerve as it exits the abdomen. The nerve may course across the iliac crest posterior to the anterosuperior iliac spine (type A) (top, left); may be ensheathed in the inguinal ligament just medial to the anterosuperior iliac spine (type B) (top, center); may be ensheathed in the tendinous origin of the sartorius muscle medial to the anterosuperior iliac spine (type C) (top, right); may be found in an interval in between the sartorius muscle and the iliopsoas muscle deep to the inguinal ligament (type D) (bottom, left); or may be found in the most medial position on top of the iliopsoas muscle, contributing the femoral branch to the genitofemoral nerve (type E) (bottom, right). (Reprinted with permission from Aszmann OC et al. Anatomical course of the lateral femoral cutaneous nerve and its susceptibility to compression and injury. Plast Reconstr Surg. 1997; :600-604. Copyright 1997, Lippincott Williams & Wilkins.)
Meralgia paresthetica can result from several causes: ischemia, stretch injury, direct trauma to the upper thigh or pelvic region, compressive irritation in this area by restrictive clothing, THA, or tissue concentrated around the pelvic region. Obese patients have an increased incidence of the neuropathy.10,11
Symptoms range from numbness and paresthesias (eg, tingling, burning, or gnawing) to extreme, crippling pain in the anterior and lateral portions of the thigh.10 The symptoms complex and the spectrum of severity are highly variable. Meralgia paresthetica is a well-documented condition, but because of the variability in presentation, it is frequently misdiagnosed or overlooked.9,12
Diagnosis of meralgia paresthetica is usually made through patient descriptions and physician palpitation of the affected area. If these measures fail to achieve a definitive diagnosis, electrodiagnostic testing by stimulation of the lateral femoral cutaneous nerve can be used. If stimulation of the nerve reproduces the pain, the diagnosis of meralgia is established.
Meralgia paresthetica has been documented as a possible complication after THA, but it usually occurs in the ipsilateral limb.13-16 Ahsan and Curtin13 reported on a patient who developed meralgia paresthetica as a direct result of lateral femoral cutaneous nerve compression by tight circular bands; the bands presumably formed as an anatomical response after the procedure. Kaspar et al14 reported on several patients who had permanent and transient lateral femoral cutaneous nerve sensory loss after THA.
Contralateral limb neurologic complications after THA are rare. Lachiewicz and Latimer4 reported 6 contralateral complications in 250 THA cases, 4 of which were related to nerve compression in obese patients. They surmised that the patients weight and the duration of the surgery resulted in crush injuries to the supporting limb. The pathogenesis was one of muscle necrosis from prolonged tissue compression. Therefore, these patients were diagnosed as having rhabdomyolysis, not meralgia paresthetica.
Our patient experienced similar contralateral leg complications, suggesting that a crush injury may have occurred. However, the diagnosis of muscle necrosis is questionable, particularly because the patient had made a nearly full recovery 5 months postoperatively, did not have any immediate postoperative strength impairment, and did not have myoglobinuria. The most likely explanation for our patients meralgia paresthetica is that it developed secondary to direct compression while in the lateral decubitis position. The duration of the surgery and the patients obesity necessitated the use of the bean-bag positioner. This device may have placed undue localized pressure on the contralateral leg and pelvic region near the lateral femoral cutaneous nerve. The rarity of meralgia paresthetica as a complication suggests that anatomical anomalies may also be implicated.
Meralgia paresthetica can often be effectively treated nonoperatively with local nonsteroidal anti-inflammatory drugs.7 Topical agents (capsaicin and lidocaine-prilocaine) can be used with protective padding to decrease surface sensitivity. Local lidocaine-corticosteroid injections may mediate inflammation. Local anesthetics act as nerve blockers, deadening the pain. Although repeated treatments may be necessary to obtain full recovery,7 nonsurgical interventions seem to be successful for most patients. Williams and Trzil17 reported recovery in 91% of 277 meralgia patients with nonoperative measures.
If nonoperative measures fail and the condition persists, surgical intervention may be considered as the final option. Three procedures are commonly used: neurolysis of constricting tissue, neurolysis and translocation of the lateral femoral cutaneous nerve, and transection with partial excision of the lateral femoral cutaneous nerve.7 Transection and neurolysis have been reported to provide positive long-term relief.1
Our patient was treated with a single local injection of cortisone and regained sensation nearly 5 months after the onset of meralgia paresthetica. Her recovery may have been the result of a combination of factors. The local injection and her increasing comfort with the prosthesis may have relieved much of the pressure that was inflaming her right lateral femoral cutaneous nerve.
We suggest that, to guard against this potential complication in obese patients undergoing THA, the surgeon should consider using a supine rather than a lateral decubitus patient position and give some attention to the choice and location of support mechanisms stabilizing the contralateral limb.
- DeHart MM, Riley LH Jr. Nerve injuries in total hip arthroplasty. J Am Acad Orthop Surg. 1999; 7(2):101-111.
- Della Valle CJ, Di Cesare PE. Complications of total hip arthroplasty: neurovascular injury, leg-length discrepancy, and instability. Bull Hosp Jt Dis. 2001-2002; 60(3-4):134-142.
- Wasielewski RC, Crossett LS, Rubash HE. Neural and vascular injury in total hip arthroplasty. Orthop Clin North Am. 1992; 23(2):219-235.
- Lachiewicz PF, Latimer HA. Rhabdomyolysis following total hip arthroplasty. J Bone Joint Surg Br. 1991; 73(4):576-579.
- Hardinge K. The direct lateral approach to the hip. J Bone Joint Surg Br. 1982; 64(1):17-19.
- Butler R, Webster MW. Meralgia paresthetica: an unusual complication of cardiac catheterization via the femoral artery. Catheter Cardiovasc Interv. 2002; 56(1):69-71.
- Grossman MG, Ducey SA, Nadler SS, Levy AS. Meralgia paresthetica: diagnosis and treatment. J Am Acad Orthop Surg. 2001; 9(5):336-344.
- Aszmann OC, Dellon ES, Dellon AL. Anatomical course of the lateral femoral cutaneous nerve and its susceptibility to compression and injury. Plast Reconstr Surg. 1997; 100(3):600-604.
- Ivins GK. Meralgia paresthetica, the elusive diagnosis: clinical experience with 14 adult patients. Ann Surg. 2000; 232(2):281-286.
- Macgregor AM, Thoburn EK. Meralgia paresthetica following bariatric surgery. Obes Surg. 1999; 9(4):364-368.
- Yang SH, Wu CC, Chen PQ. Postoperative meralgia paresthetica after posterior spine surgery: incidence, risk factors, and clinical outcomes. Spine (Phila Pa 1976). 2005; 30(18):E547-E550.
- Ulkar B, Yildiz Y, Kunduracioglu B. Meralgia paresthetica: a long-standing performance-limiting cause of anterior thigh pain in a soccer player. Am J Sports Med. 2003; 31(5):787-789.
- Ahsan MR, Curtin J. Meralgia paresthetica following total hip replacement. Ir J Med Sci. 2001; 170(2):149.
- Kaspar S, Winemaker MJ, de V de Beer J. Modified iliofemoral approach for major isolated acetabular revision arthroplasty. J Arthroplasty. 2003; 18(2):193-198.
- Dellon AL, Mont M, Ducic I. Involvement of the lateral femoral cutaneous nerve as source of persistent pain after total hip arthroplasty. J Arthroplasty. 2008; 23(3):480-485.
- Kitson J, Ashworth MJ. Meralgia paraesthetica. A complication of a patient-positioning device in total hip replacement. J Bone Joint Surg Br. 2002; 84(4):589-590.
- Williams PH, Trzil KP. Management of meralgia paresthetica. J Neurosurg. 1991; 74(1):76-80.
Mr Weier and Drs Jones and Hungerford are from the Department of Orthopedic Surgery, The Johns Hopkins University, Baltimore, Maryland.
Mr Weier and Drs Jones and Hungerford have no relevant financial relationships to disclose.
Correspondence should be addressed to: Marc W. Hungerford, MD, c/o Elaine P. Henze, BJ, ELS, Editorial Services, Department of Orthopedic Surgery, Johns Hopkins Bayview Medical Center, 4940 Eastern Ave, #A665, Baltimore, MD 21224-2780 (firstname.lastname@example.org).