Sometimes a problem arises in differentiating hip pain from back pain. Weakness in the low back can create a soft-tissue imbalance, resulting in more tension being absorbed in the hip joint.1 Thus, a chronic low back problem could enter with hip involvement causing knee pain, groin pain, leg-length changes, and limited hip motion.
It is important to try to determine the location and underlying mechanism of hip pain. Is the pain intra-articular, extra-articular or referred? Diffuse pain over the anterior thigh to the knee or shin, and pain in the mid-inguinal area, lateral thigh, medial thigh, medial knee, buttock, or posterior ilium may be referred pain from the hip joint and bursae. The hip often is overlooked as a source of pain because attention mistakenly is directed to the lumbar spine or sacroiliac joint.2 Loads of up to eight times one's body weight have been demonstrated in the hip joint during jogging, and greater loads probably occur with more vigorous exercise.3 Posterior and lateral buttock pain on lumbar extension usually is due to spinal disease, but examiners must be aware that hip extension also occurs with lumbar extension, so that the hip must not be overlooked.
McGann4 describes a test to help differentiate hip pain from spinal pain, especially in spinal stenosis of the foraminal type, which may cause symptoms below the knee. If a patient exhibits a positive Kemp sign (pain by passive extension and rotation toward the painful side in the standing position), have the standing patient flex the painful hip and knee while extending and rotating the trunk in the above Kemp position. This position relaxes the hip, since all the ligaments are relaxed during hip flexion, and continues the stress on the spine. If hip and leg symptoms persist in this position, the spine probably is involved; if the symptoms are relieved, a hip disorder likely is present.
In general, limited motion in a joint that results in pain or pain upon muscle contraction, usually points to a trouble site. Limited internal rotation, which can be determined with the patient in the sitting or supine position, is one of the most significant hip findings. Limited, painful hip internal rotation often is linked to effusion or trauma associated with a limp and walking with the lower extremity in external rotation. Limited, painful internal hip rotation is found in internal derangements; slipped capital femoral epiphysis; muscular contracture (shortness of external hip rotators); sprain or partial rupture of the ischiofemoral ligament or the descending medial part of the iliofemoral ligament; hip bursitis (trochanteric, iliopectineal); or upper rectus tendonitis.2 Almost every hip osteoarthritis is associated primarily with decreased internal hip rotation, followed by reduced hip flexion.5
According to Braly, et al.,6 in the Thomas test, if the supine patient holds the nonaffected leg in a flexed position and the opposite knee flexes so the thigh cannot reach the table, this usually indicates a hip flexor contracture. They also state that if clicking is audible during this test, it might indicate a labral tear or tightening of the iliotibial band. Clicking probably indicates a labral tear, but a louder, more audible pop might be a snapping of the psoas tendon.
A test to assess the hip for trauma in sports events is a heel strike test; striking the heel of the foot will reproduce pain if the fracture has occurred in the femoral neck. Brady and colleagues also state that "rolling the leg in the Z axis on the table will reproduce pain in femoral fractures." Both tests indicate radiographic evaluation.6
Especially in athletes, a condition called femoroacetabular impingement (FAI) is rather common.7 According to a recent study, 36 percent of professional and Olympic-level athletes (57 of 157) who underwent hip arthroscopic surgery between September 2000 and April 2005, required decompression of FAI.7 The basic cause of this impingement is related to an abnormally shaped femoral head contacting a normal acetabulum or a normal femoral head contacting an abnormally shaped deep or retroverted acetabulum, resulting in impingement affecting labral and chondral areas. The most common complaint is anterior groin pain exacerbated by hip flexion. Patients complain of pain with prolonged sitting, putting on shoes and socks, and getting in and out of the car. Flexing the hip to 90 degrees and internally rotating can cause sharp groin pain - a positive "impingment sign." This is "thought to be triggered when the bony prominence at the junction of the femoral head and neck hits into the acetabulum and labral tissue."7
This condition should be considered when there is lateral hip pain during the Patrick FABER test. Another test that may indicate FAI is testing the patient in the lateral recumbent position with the pain side up. The examiner stands behind the patient with one hand on the hip and the other hand holding the knee. Move the leg to cause the hip to go into flexion adduction and internal rotation. This position assesses impingement from the femoral neck which may have caused an acetabular tear and reproduce the patient's pain. A lateral rim impingement can be elicited by taking the leg from flexion to extension in continuous abduction to reproduce the pain.
Acetabular hip tears appear similar to knee meniscal tears, with symptoms such as sharp, catching pain and popping, and a feeling of joint locking. However, the symptoms often are more subtle, such as a dull, activity-related or positional pain that just doesn't seem to improve. Pain may be localized to the anterior groin, just proximal to the trochanter or deep within the buttock. Activities that involve force adduction of the hip joint, in association with rotation in either direction, also tend to aggravate the pain. The acetabular labrum contains free nerve endings in all parts and is involved in nociceptive and proprioceptive mechanisms.
To test for an anterior labral tear, position the patient supine; start from a passive acute hip flexion, external rotation and full abduction, and then extend the hip with internal rotation and adduction back to the neutral position. There may be pain, with or without an associated click, in patients with an anterior labral tear. To test for a posterior labral tear, start from a passive acute hip flexion, internally rotated and adducted position, and then extend the hip with abduction and external rotation to the neutral hip position. There may be a sharp pain with or without a click with a posterior labral tear.2 Treatment consists of protected weight-bearing for about four weeks, which allows approximately 13 percent of patients to respond. Arthroscopic debridement is successful. Loose-body manipulation can be attempted.
References
- Longjohn D, Door LD. Soft tissue balance of the hip. J Arthroplasty 1998;13(1):97-100.
- Hammer W. Functional Soft Tissue Examination & Treatment by Manual Methods, 3rd edition. Jones & Bartlett, Sudbury, MA, 2007 (in press).
- Crowninshield RD, Hohnston RC, Andrews JG, et al. A biomechanical investigation of the human hip. J biomech 1978;11:75-85.
- McGann WA. "History and Physical Examination." In: Steinberg ME, Editor. The Hip and Its Disorders. Philadelphia: W.B. Saunders; 1991.
- Altman R, Alarcon G, Appelrouth D, et al. The American College of Rheumatology criteria for the classification and reporting of osteoarthritis of the hip. Arthritis Rheum 1991;34:505-515.
- Braly BA, Beall DP, Martin HD. Clinical examination of the athletic hip. Clin Sports Med 2006;25:199-210.
- Philipon MJ, Schenker ML. Arthroscopy for the treatment of femoroacetabular impingement in the athlete. Clin Sports Med 2006;25:299-308.
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