A 63-year-old man comes to the physician's office due to long-standing osteoarthritis that is refractory to over-the-counter analgesics. After discussing various treatment options with his physician, the patient is referred to a surgeon for right total hip arthroplasty. His acute postoperative course is unremarkable. During a follow-up appointment, the patient reports difficulty walking despite minimal pain. On examination, he leans to his right side when walking. When asked to stand on his right leg, the patient's left hip tilts downward. Which of the following nerves is most likely injured in this patient?

Question

A 63-year-old man comes to the physician's office due to long-standing osteoarthritis that is refractory to over-the-counter analgesics.  After discussing various treatment options with his physician, the patient is referred to a surgeon for right total hip arthroplasty.  His acute postoperative course is unremarkable.  During a follow-up appointment, the patient reports difficulty walking despite minimal pain.  On examination, he leans to his right side when walking.  When asked to stand on his right leg, the patient's left hip tilts downward.  Which of the following nerves is most likely injured in this patient?

Quizplus · Accepted Answer

11ec160b_35ab_4200_9249_b1545692161f_MD0001_00 This patient has superior gluteal nerve injury, which is most often caused by pelvic trauma or iatrogenic damage occurring during hip surgery or buttocks injections. The superior gluteal nerve innervates the gluteus medius, gluteus minimus, and tensor fasciae latae muscles. These muscles function to stabilize the pelvis and abduct the thigh. Weakness of the gluteus medius and gluteus minimus muscles will cause the pelvis to sag toward the unaffected (contralateral) side when the patient stands on the affected leg (positive Trendelenburg sign). When walking, the patient will lean toward the affected (ipsilateral) side to compensate for the hip drop (gluteus medius lurch). (Choice A) The femoral nerve innervates the muscles responsible for flexion of the thigh at the hip (eg, iliacus and sartorius muscles) and extension of the leg at the knee (eg, quadriceps femoris). It also supplies sensory innervation to the skin on the anterior thigh and medial leg. Injury results in knee buckling and loss of the patellar reflex. (Choice B) The inferior gluteal nerve innervates the gluteus maximus muscle, which is responsible for extension and external rotation of the thigh at the hip. Inferior gluteal nerve injury typically causes difficulty in rising from a seated position and climbing stairs. (Choice C) Injury of the obturator nerve causes impaired thigh adduction and medial thigh sensory loss. (Choice D) The sciatic nerve innervates the muscles in the posterior compartment of the thigh (ie, hamstrings). It subsequently divides into the tibial and common fibular/common peroneal nerves, which provide motor and sensory innervation to the leg and foot. Educational objective: Superior gluteal nerve injury results in weakness and paralysis of the gluteus medius, gluteus minimus, and tensor fasciae latae muscles. This causes the pelvis to tilt downward toward the contralateral side (positive Trendelenburg sign). Patients will also lean toward the ipsilateral side when walking to help stabilize the pelvis (gluteus medius gait).

A 63-Year-Old Man Comes to the Physician's Office Due to Long-Standing