Hip Pain

Clinical appearance

Pain in the hip region may originate in tendinous, bursal, articular, or osseus structures or other soft tissues. It may also be due to radiculopathy or peripheral nerve injury, or be referred from elsewhere. The initial assessment should be based on the actual location of pain. Never take for granted that "hip pain" actually originates in the hip joint! To the presenting report "my hip hurts," ask "where in the hip?" The patient may point to the anterior, the lateral, or the posterior aspect of the joint (Table 12).

Differential diagnosis

Anterior pain.

Pain originating in the hip joint is experienced anteriorly, mainly in the groin and anteromedial thigh. Other possible projection areas, concurrent with the former, include the trochanteric region and sometimes the gluteal region. Hip joint disease is usually associated with limitation of motion and endpoint pain. Additional causes of anterior hip pain include iliopsoas tendinitis, capsular stretching, and iliopsoas bursitis (25). Both tendinitis and capsular stretching feature pain on traction, whereas tendinitis also causes pain on resisted motion. Pain on direct compression is a feature of iliopsoas bursitis. Lumbar radiculopathy, plexopathy, and femoral nerve neuropathy are identified by patellar tendon hyporeflexia, a positive inverted Lasègue's sign (pain reproduction on hyperextension of the thigh), and anteromedial thigh and/or medial leg hypoesthesia. Iliohypogastric, ilioinguinal, and genitoinguinal neuropathies may occur as a complication of a McBurney muscle splitting incision, after a herniorrhaphy, or by muscle entrapment neuropathy. A band of hypoesthesia over the lower abdominal wall, the inguinal ligament, and the base of the scrotum (or labia) is highly suggestive of the diagnosis.

Lateral pain.

Diagnosis of lateral hip pain may be difficult. Hip arthritis in general does not solely cause lateral pain. Trochanteric bursitis affects the bursa between the fascia lata and the greater trochanter. Bursal inflammation of the bursae underlying the gluteus medius or minimus has also been described. Trochanteric bursitis is usually idiopathic, but other causes include leg length discrepancy (pain develops in the long leg side), painful processes of the lower extremity at any level, and scoliosis. Iliotibial band shortening may be a contributing factor. Clinical features that suggest iliotibial tightness include lateral thigh pain while sitting with the legs crossed (in the adducted thigh), lateral knee pain, and a positive Ober or Gautam test (26). Septic or tuberculous trochanteric bursitis is extremely rare. Radiating pain from the lumbar spine is dull and is associated with lumbar/gluteal pain. Neuropathies affecting the subcostal, iliohypogastric, and lateral cutaneous nerve of the thigh (meralgia paresthetica) cause lateral pain, paresthesias, and hypoesthesia in the corresponding territories near the iliac crest, the area just below it, and the lateral thigh, respectively. Bone pathology in the femoral neck, such as a bone insufficiency fracture, and occasionally aseptic necrosis of the femoral head may cause predominantly trochanteric pain. Also, soft tissue or bone malignancy may affect the trochanteric region, and their presence should be suspected whenever a bulge is felt. Radiographic studies are negative in routine cases of trochanteric bursitis but are very helpful in defining bone lesions. Echography and MRI effectively detect soft tissue tumors and trochanteric bursitis. Bone scans detect intraosseus or intraarticular processes.

Posterior pain.

Posterior hip pain is less common than anterior and lateral pain. Pain may originate in the lumbar spine, occasionally in the sacroiliac joint, and in some cases in the hip joint, although hip joint disease almost always has coexistent anterior pain. Pain that originates in the ischial tuberosity (ischial bursitis) is aggravated by sitting. Calcific tendinitis of the posterior thigh is a self-limited condition in which calcification, sometimes with lysis of the underlying cortical bone, develops at the femoral insertion of the gluteus maximus and/or vastus lateralis tendons. The lesion may be visible on plain x-rays or may require CT for diagnosis.

Treatment

The treatment of trochanteric pain caused by trochanteric bursitis involves identification of underlying factors, such as a 2.5-cm leg length discrepancy in favor of the affected side plus ipsilateral iliotibial band contracture, and is key to a successful long-term treatment. In such a patient, a 1.25-cm heel lift should be provided for the short limb, and the patient should be referred to physical therapy for instruction on iliotibial band stretching exercises. Corticosteroid infiltration is an effective mode of therapy (27). Patients refractory to medical therapy should be evaluated by an orthopedist. A longitudinal split of the iliotibial band, which relieves pressure on the underlying trochanteric bursae, often alleviates the pain (28).

Role of the primary care physician

The primary care physician should determine whether the pain has an articular or extra-articular origin. Articular hip pain most often arises in the groin or anterior thigh and may be due to osteoarthritis, avascular necrosis, or systemic rheumatic disease. Occasionally, hip articular disease causes referred pain at the knee. If articular disease is found, the patient should be referred to a rheumatologist for further evaluation and treatment recommendations. Trochanteric bursitis and fibromyalgia can be treated by primary care physicians. Ultrasound or MRI are needed to diagnose a soft tissue lesion that will ultimately require a tissue diagnosis.

Key issues

In hip region pain, the main issue is to distinguish hip joint disease from soft tissue problems or radiating pain. Early identification of hip joint disease is important. Trochanteric bursitis, the most common cause of pain in the hip region, responds well to corticosteroid infiltrations and has an excellent prognosis if causative factors are corrected. Because sarcomas have a predilection for the root of the limbs, particularly in the lower limb, any soft tissue bulge must be viewed with great suspicion.