Pure pincer impingement arises from a prominent acetabular rim, causing overcoverage of the femoral head. Acetabular labral tears result from the repetitive impaction with flexion and internal rotation.
Patients report an insidious onset of groin pain that is exacerbated by flexion-type sports, such as hockey, football, and golf,19 as well as activities of daily living. In patients with cartilage damage, even walking can be painful. Physical examination of patients with FAI reveals findings that are similar to those of patients with acetabular labral tears. Abnormally large cam lesions or acetabular overcoverage will result in restriction of hip ROM, especially internal rotation and flexion due to a mechanical block.
Radiographs (FIGURE 2) are essential to diagnose FAI and to distinguish this condition from an isolated labral tear.20 Cam impingement will be best demonstrated on a cross-table lateral radiograph, which shows an asphericity of the femoral head/neck junction anteriorly, while pincer impingement will show overcoverage of the femoral head on an AP radiograph. MRI or magnetic resonance arthrography (MRA) is frequently obtained to see whether any cartilage deterioration has occurred. Computed tomography, which can provide a 3-dimensional reproduction of the hip morphology, is often used for preoperative planning when surgical intervention is required.
FIGURE 2
Femoral acetabular impingement with a prominent pincer lesion
Treatment. Surgical intervention is often needed to correct or remove the abnormal anatomy, and both arthroscopic and open surgery are recommended.20 Both methods include osteoplasty at the femoral head/neck junction and/or the acetabular rim to allow the proximal femur to articulate with the acetabulum without injury to the labrum with flexion and internal rotation.21
Results of both open and arthroscopic osteoplasty of the femur and acetabulum are still preliminary, with only a few studies reporting mid-term results. Open surgery typically has longer recovery and rehabilitation, but advocates emphasize the improved ability to contour the femur or acetabulum. Both open and arthroscopic procedures have about an 8% to 13% rate of revision in short-term follow-up.17
Labral tears occur with trauma and certain sports
In addition to FAI, causes of labral tears include dysplasia, instability, trauma, and degeneration, as well as sports that require repetitive hip flexion and/or pivoting, such as hockey, soccer, and football.22,23
Patients with labral tears typically present with anterior hip pain radiating to the groin, worsening with twisting motions, running, walking, and sitting for prolonged periods. Clicking or catching may occur, as well. Patients may exhibit what one researcher called the “c-sign”—so named for the shape patients make with their hand as they grip their hip just above the greater trochanter to indicate where it hurts.4 The work-up for labral tears includes radiographs and, often, MRA, which is nearly 100% specific.24
Treatment. Conservative treatment, which may include activity modification or rest and ice, nonsteroidal anti-inflammatory drugs (NSAIDs), and physical therapy, is often effective for labral tears; when such measures fail, surgical intervention is indicated. A systematic review found a 67% satisfaction rate after 3.5 years in patients who had undergone labral debridement, and complete resolution of mechanical symptoms in nearly 50%.25 Another study showed similar results for hip arthroscopy, with symptom relief continuing for 4.8 years after surgery, on average, and 84% of patients able to return to their previous level of activity.26
The long-term results of labral debridement are unknown, however, and the possibility of an association between this procedure and the development of arthritis remains. Most specialists prefer anatomic repair to restore normal hip kinematics and, potentially, long-term hip function,27,28 but structural abnormalities must also be addressed to prevent failure of the repair or recurrent tears.
Iliopsoas tendonitis: You know the snap
Often referred to as internal snapping of the hip or internal coxa saltans, iliopsoas tendonitis/bursitis can be a recalcitrant cause of anterior hip pain. Snapping of the iliopsoas leading to bursitis or tendonitis can occur at the iliopectineal eminence, the femoral head, or the lesser trochanter.29 Runners and ballet dancers are often affected.30,31
Snapping in itself is not an indication of pathology, but chronicity of symptoms is. Patients with relatively acute symptoms typically have only bursitis, while a longer duration of symptoms leads to tendonitis or tendinopathy.32
Treatment. First-line therapy is nonoperative, and includes activity modification, rest, ice, NSAIDs, and physical therapy. Advise patients to refrain from activities causing pain, and to apply ice to the affected every 20 minutes (with a 20- to 30-minute off period) for one to 2 hours. Physical therapy focuses on stretching the iliopsoas and rectus femoris muscles and strengthening the hamstring muscles to relieve the stress on the anterior pelvis. If such treatment is unsuccessful, ultrasound can be used to guide a therapeutic injection of cortisone.33 If this fails to bring relief, fractional lengthening of the iliopsoas tendon can be performed to eliminate snapping and relieve pain.34