By Bob Yarbrough, M.D.

From ATLANTA Medicine, Vol. 86, No. 1

Injuries surrounding the hip are common sources ofpain in adults. Effective treatment relies on accurate diagnoses and pointed treatments. Often, hip pain is mistakenly diagnosed as back pain and vice versa. Simultaneous evaluation of the lumbar spine is recommended in these patients.

Accurate diagnosis of hip problems requires a sound understanding of the anatomy and pathophysiology of hip disorders. The hip is a universal ball and socket joint that connects the lower extremity to the pelvis. The acetabulum forms the socket of the hip. The labrum, a ring of fibrous tissue that attaches around the rim of the acetabulum deepens the socket giving the hip joint inherent stability given its constrained design.

The hip is capable of motion in all three planes. Even during simple walking, motion occurs in all coronal, sagittal and transverse planes. Forces transmitted across the hip joint have been measured to be three to five times a person’s body weight and increase with activities such as stair climbing and running.

FEMOROACETABULAR IMPINGEMENT

Femoroacetabular Impingement, or “FAI” is a relatively new diagnosis in the realm of orthopaedics. FAI is a source of groin pain and is caused by abnormal morphology of the hip. Active men and women ages 40 to 50 are most often affected. They can present with anterior hip or groin pain during and after activities and may also complain of stiffness and loss of hip motion. The pain is typically intermittent and sharp. Continued FAI can lead to further cartilage damage and often develops into osteoarthritis.

There are two separately identifiable morphologic features of FAI: Cam and pincer lesions of the hip. Cam lesions are found on the femoral side and represent a loss of true sphericity of the femoral head. This lesion essentially creates a bump on the normally rounded edge of the femoral head. The lesion has been described as a “pistol-grip” deformity of the femoral head.

The pincer lesion is found on the acetabular side. Pincer lesions reflect “over coverage” of the femoral head. These lesions are often represented by a sharp spur or protuberance off the lateral edge of the acetabulum. Both lesions are visible on routine hip X-rays, best seen on the AP.

Physical examination of the hip reveals a loss of passive motion. Internal rotation and adduction are most affected. A positive “impingement” test consists of recreation of the patients’ characteristic groin pain with hip flexion, internal rotation and adduction. This is best elicited with the patient supine on the examining table. This test reproduces in the abnormal femoralacetabular contact with recreation of pain.

Standing radiographs, AP and lateral tests should be ordered to help make the diagnosis. Radiograpshs often reveal the pathognomonic cam and pincher lesions
about the hip. An MRI arthrogram can be helpful to identify associated tears of the acetabular labrum. Treatment consists of activity modification, NSAID therapy, rehabilitation and intraarticular hip injections under fluoroscopic or ultrasound guidance. When conservative measures fail, surgical intervention may be an option. Surgical options include arthroscopic repair and “hip reshaping.” Joint replacement is reserved for severe cases that fail conservative treatment.

BURSITIS

Bursitis is a painful condition caused by inflammation of the bursa, a fluid-filled sac found adjacent to many joints in the body. Hip pain in adults is frequently due to bursitis. The diagnosis is most commonly seen in females around 50 years of age.

Overuse results in excessive friction about the hip, which commonly leads to the development of bursitis. Post-traumatic bursitis is a result of a direct injury or blow to the hip. Anatomic features such as a wide pelvis also contribute to the development of bursitis.
There are three different bursae located around the hip: ischial, iliopectineal and the trochanteric. The ischial bursa is located along the posterior pelvis region and the iliopectineal is found anterior to the hip.

Trochanteric bursa is located along the lateral aspect of the hip between the iliotibial band (or IT band) and the greater trochanter of the hip. It is by far the most frequent location of bursitis. With trochanteric bursitis, patients often complain of lateral hip pain aggravated with sleeping on a side, rising from a chair and walking. Tenderness is elicited with palpation of the lateral hip, and pain is provoked with external rotation of the hip. Tightness of the overlying IT band often contributes to the problem. In addition, individuals with a broad pelvis or leg length inequality may be at increased risk for the development of trochanteric bursitis.

Treatment of trochanteric bursitis consists of activity modification, a short course of non-steroidal anti-inflammatory drugs (NSAIDs) and daily stretching of the IT band. Symptoms commonly last for several months. Refractory cases are treated with steroid injections and prescribed physical therapy. A minimum of 3 months is allowed between repeat steroid injections in the same location.

These cases can commonly persist for six months and sometimes longer. Surgery is rarely indicated.

SNAPPING HIP SYNDROME

Snapping Hip Syndrome (SHS) is a painful problem in which an audible and tactile snap occurs with certain hip movements. Typically the snapping occurs during hip flexion and extension.

The cause of the snap can be intraarticular or external to the hip joint.

When a tight iliotibial band slides over the greater trochanter, it can cause external hip snapping. The snapping is often felt and heard over the trochanteric or lateral area of the hip. Patients can usually reproduce the snapping by standing and squatting. Normally the IT band glides smoothly over the greater trochanter; however, when the posterior portion of the ITB becomes thickened, snapping can result.

Snapping can also be caused by the iliopsoas tendon catching on the femoral head as the hip moves from flexion to extension. This snapping is felt more medial, near the groin. It can often be reproduced with the patient supine on the examining table and moving the hip from extension to flexion.

Intraarticular causes of snapping hip include loose bodies, chondral damage and labral disease. The snapping is felt over the anterior hip near the groin. These patients usually cannot reproduce the snapping in clinic and often present with the complaint of hip pain and episodic “catching” of the hip. Snapping hip syndrome is usually found in younger populations and frequently related to overuse injuries involved with athletics.

A patient history and physical exam is the mainstay of diagnosis for both types of snapping. Routine X-ray imaging is recommended. In difficult or chronic cases, an MRI can be helpful to rule out other etiologies of hip pain, such as avascular necrosis, stress fracture and chondromalacia. If intra-articular snapping is suspected, an MRI arthrogram can provide a better picture of labral injuries.

With a detailed history and physical exam, most hip disorders can be accurately diagnosed at the initial presentation. Plain radiographs are very helpful at ruling out arthritis and malignancies as potential sources of pain. An MRI examination is useful in cases that are elusive and resistant to conservative treatments. Disorders of the lumbar spine must be considered and evaluated simultaneously to ensure precise treatment recommendations.

Cortisone injections can be utilized in select cases to help accelerate recovery. Consult your orthopaedist when needed.