History and Physical Examination of the Hip

Standing Examination

The general area of pain is noted by having the patient point with one finger. The groin region directs suspicion to an intraarticular problem, whereas lateral-based pain can be associated with both intraarticular and extraarticular pathology. A characteristic presenting pain pattern described by patients with hip pain is the “C sign,” in which the patient holds the hand in the shape of a C and places it above the greater trochanter, with the thumb positioned posterior to the trochanter and fingers extending into the groin. This finding can be misinterpreted as lateral soft tissue pathology, such as trochanteric bursitis or the iliotibial band; however, the patient may often describe deep interior hip pain. Posterior-superior pain necessitates a complete evaluation for differentiating hip and back pain. Often, back issues are noted concomitantly, along with musculotendinous extraarticular hip pathology.

As the patient stands ( Table 28.1 ), general body habitus is assessed and bilateral shoulder and iliac crest heights are evaluated for leg length discrepancies or pelvic obliquity. Placing incremental wooden blocks under the short-side heel will aid in orthotic considerations and leg length discrepancies. Generalized ligamentous laxity is investigated by calculating the Beighton score after assessing the patient's ability to perform a series of hypermobility tests ( Fig. 28.3 ). One point is awarded for each positive test, and a score of greater than 4/9 is indicative of generalized joint hypermobility. Forward bending allows assessment of spinal alignment and differentiation of structural versus nonstructural scoliosis. The degree of flexion at the waist is recorded. Reproduction of pain with lumbar extension and lateral bending may be indicative of a spinal etiology.

An understanding of mechanical load transfer in the hip in both static and dynamic situations is essential for assessment and diagnosis of hip pathology. Comprehensive knowledge of normal gait will aid the physician in discriminating between normal and abnormal gait patterns. Abnormal gait patterns can indicate where abnormal transfer of load is applied across the hip joint; this can result in improper force load transfer to the lower back and knee joints. Irregularities in gait are derived most often by compensating for pain perceived in stride. The musculature of the lower limbs produces the forces required for ambulation, and the ligamentous capsule maintains hip stability. This relationship emphasizes the importance of adequate postoperative rehabilitation, especially with connective tissue disorders and improper osseous alignment.

Adequate space, such as a hallway, is needed so that a full gait of six to eight stride lengths can be assessed. Gait abnormalities often help detect hip pathology and kinematic chain disorders. Gait evaluation includes observation of foot progression angle (FPA), pelvic rotation in the coronal and sagittal planes, stance phase, and stride length. FPA will indicate osseous or static rotatory malalignment, which occurs with increased femoral anteversion (in-toeing gait) or decreased femoral anteversion (out-toeing gait) versus a capsular or musculotendinous problem. Differentiation must be made for compensated or noncompensated torsion. The knee and thigh are observed simultaneously to assess rotary parameters. Secondary abnormal hip rotation may be caused by holding the knee in internal or external rotation in an effort to maintain proper patellofemoral joint alignment. This abnormal motion or battle between the hip and the knee for a comfortable position will affect the gait; this is usually seen in cases of severe increased femoral anteversion. The following are abnormal gait patterns associated with hip pathologies: winking gait with excessive pelvic rotations in the axial plane, abductor-deficient gait, antalgic gait with shortened stance phase on the painful side, and short-leg gait with dropping of the shoulder in the direction of short legs.

Long-stride gait steps are a validated measure for ischiofemoral impingement and hamstring avulsions. Patients are asked to take long walking strides to achieve terminal hip extension. Pain experienced in the posterior region during the hip extension phase of the gait can identify ischiofemoral impingement, whereas pain during the hip flexion gait phase can signify hamstring avulsion.

Careful observation of iliac crest rotation and terminal hip extension will assess pelvic rotation. On average, normal gait requires 8 degrees of hip rotation and 7 degrees of pelvic rotation, equaling a total rotation of 15 degrees. Excessive rotation in the axial plane toward the affected hip is demonstrative of producing extension and rotation through the lumbar spine to attain terminal hip extension. Excessive rotation can be associated with laxity or hip flexion contracture, which can be exacerbated by increased lumbar lordosis or a forward-stooping posture. Ischiofemoral impingement can also produce a lumbar pelvic flexion to gain hip extension. Spinal function and mechanics can be affected by gait abnormalities. In cases of excessive femoral anteversion, the patient will try to create greater anterior coverage with a rotated pelvis to achieve terminal hip extension. Anterior capsular injury or laxity can also contribute to the excessive hip rotation in terminal hip extension. Patients with a femoral anteversion greater than 30 degrees or less than −5 degrees with normal body habitus may tolerate the excessive version. Those outside or on margins of this anteversion range have less tolerance owing to body habitus. A small frame cannot tolerate the malalignment. Hip disease from any block of terminal hip extension (decreased femoral version, coxa profunda, ischiofemoral impingement, iliofemoral ligament/psoas contracture) will cause abnormal rotatory gait biomechanics.

Heel strike occurs at 30 degrees of hip flexion, thus generating maximum ground reactive forces to the hip. Neuromuscular abnormalities, trauma, and leg length discrepancies can be indicated by a shortened stance phase. Abductor weakness or disrupted proprioception can be attributed to abductor-deficient gait (Trendelenburg gait or abductor lurch). The abductor-deficient gait is an unbalanced stance phase, which may present in two ways: a pelvic shift away from the body (“dropping out” of the hip on the affected side) or a weight shift over the adducted leg (shift of the upper body “over the top” of the affected hip). Antalgic gait, a self-protecting limp caused by pain, is characterized by a shortened-stance phase on the painful side, limiting the duration of weight bearing. Differentiation of a short-leg gait involves a drop of the shoulder in the direction of the short leg.

The single-leg stance phase test is an assessment of hip joint function that simulates the single-leg stance phase with load on the examined hip. The single-leg stance phase test is performed bilaterally, with the nonaffected side examined first and serving as a baseline reference for the affected side ( Fig. 28.4 ). The single-leg stance phase position is held for 6 seconds. As the patient lifts and holds one foot off the ground, the contralateral hip abductor musculature and the neural loop of proprioception are being evaluated. If the musculature is weak, or if the neural loop of proprioception is disrupted, the pelvis will tilt toward or away from the unsupported side. A positive test is noted if the pelvis drops toward the nonbearing side or shifts more than 2 cm toward the bearing side, which may indicate weak abductor musculature, disrupted neural loop of proprioception on the bearing side, or trunk inclination. This test is also performed in a dynamic fashion.

Seated Examination

A thorough vascular, lymphatic, and neurologic examination is performed during the seated hip examination ( Table 28.2 ). Vascular and lymphatic assessment includes the posterior tibial pulse, any swelling of the extremity, and inspection of the skin. Neurologic evaluation consists of motor function, sensibility, and deep tendon reflexes (patellar and Achilles). A straight-leg raise test detects the presence of radicular neurologic symptoms and is performed by passively extending the knee into full extension. Loss of internal rotation is one of the first signs of the possibility of an intraarticular disorder ; therefore, one of the most important assessments is that of internal and external rotation in the seated position. The seated position ensures that the ischium is square to the table, thus providing sufficient stability at 90 degrees of hip flexion and a reproducible platform for accurate rotational measurement, providing that the patient is not allowed to recline or slouch during hip rotation assessment. The hip at 90 degrees flexion places the ligaments in a relaxed, loose-packed position, allowing for an osseous assessment. Hip rotation measured in different positions (seated, prone, and supine) can be compared for an assessment of ligamentous versus osseous abnormality. Gently perform passive internal and external rotation until a firm endpoint or pain is involved and compare bilaterally ( Fig. 28.5 ).

Musculotendinous, ligamentous, and osseous control of internal and external rotation is complex. Therefore, any differences in seated versus extended positions may raise the question of ligamentous versus osseous abnormality. The seated loose-packed position will test only the osseous and ligamentum teres contribution versus the hip-extended close-packed position testing ligamentous contribution. For proper hip function, sufficient internal rotation is needed. At the midstance phase of normal gait should be at least 10 degrees of internal rotation, but less than 20 degrees is abnormal. Diagnoses such as arthritis, effusion, internal derangement including labral tear, slipped capital femoral epiphysis, femoroacetabular impingement (FAI), and muscular contracture can be related to loss of internal hip rotation. Significant side-to-side differences can be related to femoroacetabular impingement or to rotational constraint from increased or decreased femoral or acetabular anteversion. Increased internal rotation combined with decreased external rotation may indicate increased femoral and/or acetabular anteversion, although hip capsular function will require further radiographic and biometric assessment.