HISTORY AND PHYSICAL EXAMINATION

History

Prior to the physical examination of the hip, the patient history is recorded. An account of the present condition, including the date of onset, the presence or absence of trauma, mechanisms of injury, pain location, and factors that increase or decrease the pain, is obtained. Treatments to date must be clearly defined, such as rest, physical therapy, ice, heat, nonsteroidal anti-inflammatory drugs (NSAIDs), surgery, injections, orthotics, and/or the use of support aids. The patient’s functional status is assessed and current limitations are detailed, which may involve getting in or out of a bathtub or car, activities of daily living, jogging, walking, and/or climbing stairs. Related symptoms of the back and neurologic, abdomen, and lower extremity complaints must also be identified. The presence of associated complaints, such as abdominal or back pain, numbness, weakness, sitting pain, length of time sitting, and coughing or sneezing exacerbation, help rule out thoracolumbar problems. Previous consultations, surgical interventions, and past injuries must also be addressed.

The location of the presenting pain and presence or absence of popping will aid in the determination of intra-articular versus extra-articular causes. Participation in sports and other activities are documented, which can help determine the type of injury. Rotation sports, such as golf, tennis, ballet, and martial arts, have been commonly associated with injuries to the intra-articular structures. Finally, treatment goals and expectations are reviewed with the patient. Treatment may vary, based on the patient’s expectations and postoperative goals. See Figure 1-1 for an illustration of a form for a complete review of the history.

FIGURE 1-1 Complete review of patient history.

A modified Harris hip or Merle d’Aubigné (MDA) score is a general guide to establish the gross levels of function. The modified Harris hip score (HHS) is the most documented and standardized functional score to date, which is a quantitative score based on pain and function. However, the high-performing athletic population may be best evaluated by the athletic hip score.¹ Other hip scores have been outlined with quantifications for more specific patient populations, such as the nonarthritic hip score (NAHS), hip disability and osteoarthritis outcome score (HOOS), musculoskeletal function assessment (MFA), short form 36 (SF-36), and the Western Ontario and McMaster University (WOMAC) osteoarthritis index.² Currently, the MAHORN (Multicenter Arthroscopy of the Hip Outcomes Research Network) Group is in the final stages of testing the hip outcomes score (HOS), which will provide an internationally accepted score and be useful for the athletic population.³

Physical Examination

The hip assumes an essential role in most activities. The hip is not only responsible for distributing weight between the appendicular and axial skeleton, but is also the joint from which motion is initiated and executed. It is known that the forces through the hip joint can reach three to five times the body’s weight during running and jumping.⁴ Hip pain often stems from some type of sports-related injury.¹ Of athletic injuries in children, 10% to 24% are hip-related, whereas 5% to 6% of adult sports injuries originate in the hip and pelvis.⁵ Athletes participating in rugby and martial arts have also been reported to have an increased incidence of degenerative hip disease.⁶ Currently, 60% of intra-articular disorders are initially misdiagnosed.⁷ An organized physical examination will help in the diagnosis of hip problems.

A consistent hip examination is performed quickly and efficiently to screen the hip, back, and abdominal, neurovascular, and neurologic systems and to find the comorbidities that coexist with complex hip pathology. Each examination or physical evaluation has a specific method of being performed, although interobserver consistency and practice is one of the most important aspects of the evaluation.⁸

The technique of physical examination is dependent on the examiner’s experience and efficiency. The most efficient order of examination begins with standing tests followed by seated, supine, and lateral tests, ending with prone tests.^9,10 The physical examination will be fine-tuned and directed through the review of the history of present illness. As with other extremity examinations, access for exposure and patient comfort with loose-fitting clothes about the waist are helpful. An assistant to record the examination on a standardized written form aids in accurate documentation and thoroughness, especially when first starting a comprehensive hip evaluation.

Recently, the MAHORN Group has identified common trends among hip specialists in the physical examination of the hip. In the standing position, common tests included gait analysis, single-leg stance phase test, and laxity. In the supine position, common tests included the following: range of motion (ROM) of hip flexion; internal and external hip ROM; flexion, adduction, internal rotation (FADDIR); dynamic internal rotatory impingement (DIRI); dynamic external rotatory impingement (DEXRIT); palpation, flexion, abduction, external rotation (FABER); straight leg raise against resistance; muscular strength; passive supine rotation; and posterior rim impingement. Common lateral position tests included palpation, passive adduction tests, and abductor strength. In the prone position, the femoral anteversion test was commonly performed. The physical examination that follows includes these points.

Standing Examination

As the patient stands (Table 1-1), a general point of pain is noted with one finger, and can usually help direct the examination. The groin region directs a suspicion of intra-articular problem and lateral-based pain is primarily associated with intra- or extra-articular aspects. A characteristic sign of patients with intra-articular hip pain is the C sign.⁸ The patient will hold his or her hand in the shape of a C and place 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 is often describing deep interior hip pain.⁸ Posterior-superior pain requires a thorough evaluation in differentiating hip and back pain. The shoulder height and iliac crest heights are noted to evaluate leg length discrepancies (Fig. 1-2). Incremental wooden blocks placed under the short side heel help in orthotic considerations. General body habitus is assessed and issues of ligamentous laxity are determined by the middle finger test or hyperextension of the elbows or knees. Structural versus nonstructural scoliosis is differentiated by forward bending and the degree of lumbar flexion is recorded. Side-bending ROM is also useful.

TABLE 1-1 Standing Examination Assessment

Examination	Assessment and Association
Abductor deficient gait	Abductor strength, proprioception mechanism
Antalgic	Trauma, fracture, synovial inflammation
Pelvic rotational wink	Intra-articular pathology, hip flexion contracture, increased femoral anteversion, anterior capsual laxity
Foot progression angle with excessive external rotation	Femoral retroversion, increased acetabular anteversion, torsional abnormalities, effusion, ligamentous injury
Foot progression angle with excessive internal rotation	Increased femoral anteversion or acetabular retroversion, torsional abnormalities
Short leg limp	Iliotibial band pathology, true-false leg length discrepancy
Single-leg stance phase test	Abductor strength, proprioception mechanism
Spinal alignment	Shoulder–iliac crest heights, lordosis, scoliosis, leg length
Laxity	Ligamentous laxity in other joints: thumb, elbows, shoulders, or knee

See video for performing seated examination tests.

FIGURE 1-2 Body habitus and laxity evaluation. A, B, Shoulder and iliac crest heights are examined with the patient with dynamic loading of the hip joint in the standing position. C, As the patient bends forward at the trunk, spinal alignment is palpated. D, The degree of truncal flexion is noted in full flexion. E, Laxity of the thumb. F, Recurvatum of the elbow.

Gait abnormalities often help detect hip pathology.^11,12 Joint stability, preservation of the labrum and articular cartilage, and proper functioning of the hip joint involve three biomechanical planes of the femur and acetabulum. These relationships are important for the transfer of dynamic and static load to the ligamentous and osseous structures.

The patient is taken into the hallway to observe a full gait of six to eight stride lengths. Key points of gait evaluation include foot rotation (internal-external progression angle), pelvic rotation in the x and y axes, stance phase, and stride length. Gait viewed from the foot progression angle will detect osseous or static rotatory malalignment, such as that which exists with increased or decreased femoral anteversion versus capsular or musculotendinous issues. The knee and thigh are observed simultaneously to assess any rotatory parameters. The knee may want to be held in internal or external rotation to allow proper patellofemoral joint alignment, but may produce a secondary abnormal hip rotation. This abnormal motion is usually present in cases of severe increased femoral anteversion, precipitating a battle between the hip and knee for a comfortable position, which will affect the gait. In cases of a painful gait, note the anatomic location of pain and at what point within the gait phase pain is manifest.

Noting iliac crest rotation and terminal hip extension assesses pelvic rotation. On average, a normal gait requires 6 to 8 degrees of hip rotation and 7 degrees of pelvic rotation, for a total rotation of 15 degrees.¹² The pelvic wink is demonstrated by an excessive rotation in the axial plane toward the affected hip, thus producing extension and rotation through the lumbar spine, to obtain terminal hip extension. This winking gait can be associated with intra-articular hip pathology, laxity, or hip flexion contractures, especially when combined with increased lumbar lordosis or a forward-stooping posture. Gait changes can affect spinal mechanics and function. Excessive femoral anteversion, or retroversion, can affect a wink on terminal hip extension because the patient will try to create greater anterior coverage with a rotated pelvis. Injury to the anterior capsule can also contribute to a winking gait.

During the stance phase, body weight must be supported by a single leg, with the gluteus maximus, medius, and minimus providing most of the force.¹² Maximum ground reactive force occurs on heel strike at 30 degrees of hip flexion. A shortened stance phase can be indicative of neuromuscular abnormalities, trauma, or leg length discrepancies. The abductor deficient gait (Trendelenburg gait or abductor lurch) is an unbalanced stance phase attributed to abductor weakness or proprioception disruption. This pattern may present in two ways—with a shift of the pelvis away from the body (a dropping out of the hip on the affected side), or with a shift of the weight over the adducted leg (a shift of the upper body over the top of the affected hip). The antalgic gait is characterized by a shortened stance phase on the painful side, limiting the duration of weight-bearing (a self-protecting limp caused by pain). A short leg gait is noted by drop of the shoulder in the direction of the short leg.

In addition to body habitus and gait evaluation, the single-leg stance phase test (Trendelenburg test) is performed during the standing evaluation of the hip. The single-leg stance phase test is performed on both legs, with the nonaffected leg examined first, to establish a baseline (Fig. 1-3). During this test, the examiner stands behind the exposed patient (to the degree that the bony landmarks are easily observed). The patient stands with the feet shoulder width apart and then brings one leg forward by flexing the leg to 45 degrees at the hip and 45 degrees at the knee, thereby simulating the single-leg stance phase with the load on the examined hip. This position is held for 6 seconds. As the patient lifts and holds one foot off the ground, the contralateral hip abductor musculature and neural loop of proprioception are being tested. The pelvis will tilt toward or away from the unsupported side if the musculature is weak or if the neural loop of proprioception is disrupted. Normal dynamic midstance translocation is 2 cm during a normal gait pattern¹²; a shift in either direction of more than 2 cm constitutes a positive shift. This test is also performed in a dynamic fashion by some examiners.

FIGURE 1-3 Single-leg stance phase test. This is performed bilaterally and observed from behind and in front of the patient. The patient holds this position for 6 seconds. A pelvic shift of greater than 2 cm is a positive result, indicating abductor weakness or proprioception disruption. A, Left leg front view. B, Right leg, front view. C, Left leg, rear view.

Seated Examination

The seated hip examination (Table 1-2) consists of a thorough neurologic and vascular examination. The need to check the basics is obvious, even in apparently healthy individuals. The posterior tibial pulse is checked first, any swelling of the extremity is noted, and inspection of the skin is performed at this time. A straight leg raise test is then performed by passively extending the knee into full extension. The straight leg raise test is helpful for detecting radicular neurologic symptoms.

TABLE 1-2 Seated Examination Assessment

Examination	Assessment and Association
Neurologic	Sensory nerves originating from the L2-S1 levels, deep tendon reflex of patella (L2-L4 spinal nerves and femoral nerve) and Achilles (L5-S1 sacral nerves)
Straight leg raise	Radicular neurologic symptoms
Vascular	Pulses of the dorsalis pedis and posterior tibial artery
Lymphatics	Skin inspection for swelling, scarring, or side to side asymmetry
Internal rotation	Normal between 20 and 35 degrees
External rotation	Normal between 30 and 45 degrees

See video for performing seated examination tests.

The loss of internal rotation is one of the first signs of an intra-articular disorder; therefore, one of the most important assessments is 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. Passive internal and external rotation testing are performed gently and compared from side to side. Seated rotation range of motion is also compared and contrasted with the extended position of the hip (Fig. 1-4).

FIGURE 1-4 Seated external (A) and internal (B) rotation range of motion. Passive internal and external rotation testing are compared from side to side. In the seated position, the ischium is square to the table, thus providing sufficient stability at 90 degrees of hip flexion. Internal and external rotation in the seated position offer a reproducible platform for the accurate rotational measurement.

Musculotendinous, ligamentous, and osseous control of internal and external rotation are complex, so any differences in seated versus extended positions may raise the question of ligamentous versus osseous abnormality. Sufficient internal rotation is important for proper hip function—there should be at least 10 degrees of internal rotation at the midstance phase of normal gait,¹² but less than 20 degrees is abnormal (see Table 1-3 for normal ROM). Pathology related to femoroacetabular impingement or to rotational constraint from increased or decreased femoral or acetabular anteversion can result in significant side-to-side differences. An increased internal rotation combined with a decreased external rotation may indicate excessive femoral anteversion and distinguished from hip capsular pathology by radiographic and biometric assessment.

Supine Examination

A battery of tests with the patient in the supine position (Table 1-4) helps distinguish internal from extra-articular sources of hip symptoms further. The supine examination begins with the assessment of leg lengths. Next, passive hip flexion range of motion is assessed (Table 1-3). Both knees are brought up to the chest and the degree of flexion is recorded (Fig. 1-5). It is important to note the pelvic position because the hip may stop early in flexion, with the end range of motion being predominantly pelvic rotation. From this position, the hip flexion contracture test (Thomas test) is performed by having the patient extend and relax one leg down toward the table (Fig. 1-6). Any lack of terminal extension, noted by the inability of the thigh to reach the table, demonstrates a hip flexion contracture. Both sides are examined for comparison. An important aspect of this test is to obtain the zero set point for the lumbar spine. Patients with hyperlaxity or connective tissue disorders could have a false-negative result. In these patients, the zero set point can be established with an abdominal contraction. The hip flexion contracture test could also be falsely negative if there is lumbar spine hyperlordosis.

TABLE 1-4 Summary of Supine Examinations and Assessment

Examination	Assessment and Association
Range of motion	Flexion, abduction, adduction
FADDIR	Anterior femoroacetabular impingement, torn labrum
Hip flexion contracture test (Thomas test)	Hip flexor contracture (psoas), femoral neuropathy, intra-articular pathology, abdominal cause
FABER (Flexion, Abduction, External Rotation)	Distinguish between back and hip pathology, specifically sacroiliac joint pathology
Dynamic internal rotatory impingement test (similar to McCarthy test)	Anterior femoroacetabular impingement, torn labrum
Dynamic external rotatory impingement test (similar to McCarthy test)	Superior femoroacetabular impingement, torn labrum
Posterior rim impingement test	Posterior femoroacetabular impingement, torn labrum
Passive supine rotation test (log roll)	Trauma, effusion, synovitis
Heel strike	Trauma, femoral fracture
Straight leg raise against resistance (Stinchfield)	Intraarticular pathology along with psoas tendonitis or bursitis. Hip flexor strength
Palpation
Abdomen

Fascial hernia, associated gastrointestinal or genitourinary pathology

Pubic symphysis

See video for performing supine examination tests.

TABLE 1-3 Normal Internal and External Rotation Range of Motion

FIGURE 1-5 Supine examination, starting position. Zero set point of the pelvis is achieved by having the patient hold the contralateral leg in full flexion, thus establishing neutral pelvic inclination.

FIGURE 1-6 Hip flexion contracture test. With the patient holding the contralateral leg in full flexion (zero set point for the lumbar spine), the examined hip is passively extended toward the table. Both hips are examined for side to side comparison. If the thigh cannot reach the table (lack of terminal hip extension), this demonstrates a hip flexion contracture.

During the course of the supine examination, any pop in this plane can sometimes be related to a snapping iliopsoas tendon. A fan test (the patient circumducts and rotates the hip in a rotatory fashion) can help delineate the presence of the snapping iliopsoas tendon over the femoral head or the innominate. Often, this diminishes with an abdominal contraction (video). A hula hoop maneuver, in which the patient stands and twists, or a bicycle test (performed in the lateral position), can help distinguish the pop internally from the external pop of coxa sultans externus caused by the subluxing iliotibial band over the greater trochanter.

The FABER test, conventionally known as the Patrick test, is helpful in determining hip versus lumbar complaints (Fig. 1-7). Re-creation of hip pain can be associated with musculotendinous or osseous posterior lateral acetabular incongruence or ligamentous injury. In cases of a coup-contrecoup injury, in which the mechanism of injury is initiated posteriorly, pain will be secondarily referred to anteriorly.

FIGURE 1-7 Flexion, abduction, external rotation test (FABER) test. The examiner brings the leg into 90 degrees of flexion and externally rotates and abducts it so that the ipsilateral ankle rests distal to the knee of the contralateral leg. The passive abduction ROM can be measured by fist widths and compared side to side.

A variety of tests are used for the detection of impingement or intra-articular pathology. The degree of flexion required in this position of adduction—internal rotation depends on the degree of impingement and type and location of the impingement.

For the DIRI test, the patient is in the supine position and instructed to hold the nonaffected leg in flexion beyond 90 degrees, thus establishing a zero pelvic set point and eliminating lumbar lordosis. The examined hip is then brought into 90 degrees of flexion or beyond and is passively taken through a wide arc of adduction and internal rotation (Fig. 1-8). A positive result is noted with re-creation of the complaint pain. DIRI can also be performed in the operating room for direct visualization of femoral neck and acetabular congruence (video).

FIGURE 1-8 Dynamic internal rotatory impingement (DIRI) test. A, DIRI begins with the hip at 90 degrees flexion or beyond. B, It is then passively taken through a wide arc of adduction and internal rotation (arrows) while decreasing flexion to about 80 degrees.

For the DEXRIT test, the patient is in the supine position and instructed to hold the nonaffected leg in flexion beyond 90 degrees, thus eliminating lumbar lordosis. The hip is then brought into 90 degrees flexion or beyond and dynamically taken through a wide arc of abduction and external rotation (Fig. 1-9). A positive result is noted with re-creation of pain. DEXRIT can be performed intraoperatively for direct visualization of femoral neck and acetabular congruence (video).

FIGURE 1-9 The dynamic external rotatory impingement test (DEXRIT). A, DEXRIT begins with the hip at 90 degrees flexion or beyond. B, C, It is then dynamically taken through a wide arc of abduction and external rotation (arrows).

Passive abduction and adduction range of motion are assessed in the supine position (see Table 1-3). Palpation of the abdomen is performed and any tenderness is documented (Fig. 1-10). Abdominal tenderness is differentiated from fascial hernia and/or adductor tendinitis. Resisted torso flexion with palpation of the abdomen will differentiate the fascial hernia from other complaints. Palpation of the adductor tubercle with active testing will detect adductor tendonitis. Common physical examination findings associated with athletic pubalgia include inguinal canal tenderness, pubic crest-tubercle tenderness, adductor origin tenderness, pain with resisted sit-ups or hip flexion, and a tender, dilated superficial ring.

FIGURE 1-10 A, Palpation of the abdomen in the relaxed supine position. B, Palpation of the adductor tubercle. C, Palpation of the abdomen with an abdominal contraction.

Other useful tests may include Tinel’s test of the femoral nerve. This test is found to be positive with hip flexion contractures of more than 25 degrees as a result of the proximity of the psoas tendon and femoral nerve. A heel strike is performed by striking the heel abruptly. A positive response is indicative of trauma or a stress fracture (Fig. 1-11A). The passive supine rotation test (log roll) involves passive internal and external rotation of the femur, with the leg lying in an extended or slightly flexed position (see Fig. 1-11B). The passive supine rotation test is performed bilaterally and any side to side differences in this maneuver can alert the examiner to the presence of laxity, effusion, or internal derangement. The straight leg raise against resistance test (Stinchfield test) is an assessment of hip flexor and psoas strength and is a sign of an intra-articular problem as the psoas places pressure on the labrum. The patient performs an active straight leg raise, with the knee in extension up to 45 degrees; the examiner’s hand is then placed distal to the knee while applying a downward force (see Fig. 1-11C). A positive test is noted with re-creation of the complaint, pain, or weakness.

FIGURE 1-11 Additional tests in the supine position. A, The heel strike is performed by striking the heel abruptly. B, The passive supine rotation test involves passive internal rotation (shown) and external rotation of the femur, with the leg lying in an extended position. C, Straight leg raise against resistance.

The importance of multiple examinations is recognized for the detection of intra-articular pathology. Even in the presence of normal internal and external rotation, there is a need for further delineation of the relationships that exist among the musculotendinous, osseous, and ligamentous structures. Tests for impingement can have good specificity and reasonable predictive value for osseous abnormalities; however, no single test is sensitive enough to be used exclusively. Furthermore, the ligamentous contribution to range of motion varies with flexion and rotation.¹³

The posterior rim impingement test can also be performed in the supine position. The patient is positioned at the edge of the examining table so that the examined leg hangs freely at the hip and the patient draws up both legs in to the chest, eliminating lumbar lordosis. The affected leg is then extended off the table, allowing for full extension of the hip, abducted and externally rotated (Fig. 1-12). The posterior rim impingement test takes the hip into extension and assesses the congruence of the posterior acetabular wall and femoral neck. A variation of this test is the lateral rim impingement test (see next section).

FIGURE 1-12 Posterior rim impingement test. The patient rests at the edge of the examining table, with the affected leg hanging freely at the hip while holding the contralateral leg in full flexion. The examined leg is then brought into full hip extension, abducted, and externally rotated (arrow).

Lateral Examination

The lateral examination (Table 1-5) begins with the patient on the contralateral side and palpating the areas of the suprasacroiliac and sacroiliac (SI) joint, muscles of abduction, and origin of the gluteus maximus as it inserts along the lateral border of the sacrum and the most posterior aspect of the ilium. The next point of palpation is the ischium for detection of avulsions or bursitis. Finally, the piriformis and sciatic nerve are palpated for any signs of tenderness, along with the abductor musculature, which includes the glutei (maximus, medius, and minimus) and tensor fascia lata. An active piriformis test is performed by the patient pushing the heel down into the table, abducting and externally rotating the leg against resistance, while the examiner monitors the piriformis (Fig. 1-13). The active piriformis test is similar to Pace’s sign, which is pain and weakness on resisted abduction and external rotation of the thigh in the seated position.¹⁴ A set of passive adduction tests (similar to Ober’s test) are performed with the leg in three positions (Fig. 1-14)—extension (tensor fascia lata contracture test), neutral (gluteus medius contracture test), and flexion (gluteus maximus contracture test). Gluteus medius tension is assessed by relaxation of the iliotibial band with knee flexion. In this position, the hip should adduct down toward the table. Any restrictions of these motions are recorded. When performing the gluteus maximus contracture test, the shoulder is rotated toward the side of the table, with the hip flexed and knee extended. If adduction cannot occur in this position, the gluteus maximus portion is contracted. The hip should freely be able to come into a full adducted position and any restriction of the gluteus maximus is recognized. The gluteus maximus is balanced with the tensor fascia lata anteriorly. If the hip does not come beyond the midline in the longitudinal axis of the torso, it is graded as a 3+ restriction above torso, 2+ restriction at the midline, and 1+ restriction below. A clear delineation of the exact area of restriction will help direct physical therapy and peritrochanteric treatment options. Strength is assessed with any type of lateral-based hip complaint. The gluteus medius strength test is performed with the knee in flexion (Fig. 1-15) to release the iliotibial band contribution.

TABLE 1-5 Summary of Lateral Examinations and Assessment

See video.

FIGURE 1-13 Active piriformis test. With the patient in the lateral position, the examiner palpates the piriformis. The patient drives the heel into the examining table, thus initiating external hip rotation while actively abducting and externally rotating against resistance (arrows).

FIGURE 1-14 Passive adduction tests. A, The Tensor fascia lata contracture test: With the knee in extension, the examiner passively brings the hip into extension then adduction. B, Gluteus medius contracture test is performed with knee flexion, thus eliminating contribution of the iliotibial band and zero flexion. The examiner passively adducts the hip toward the examination table. C, The gluteus maximus contracture test is performed with the ipsilateral shoulder rotated toward the examination table (arrow). With the examined leg held in knee extension, the examiner passively brings the hip into flexion and then adduction.

FIGURE 1-15 Abductor strength. A, Gluteus medius strength is evaluated by having the patient perform active hip abduction with knee flexion (arrows). B, Gluteus maximus strength is evaluated by active hip abduction with knee extension (arrows).

Next is the passive FADDIR assessment, which is performed in a dynamic manner (Fig. 1-16). The examiner holds the monitoring hand in and about the superior aspect of the hip with the lower leg cradled on the forearm and the knee on the hand. The hip is then brought into flexion, adduction, and internal rotation. Any reproduction of the patient’s complaint and the degree of impingement are noted. FADDIR is commonly performed as part of the supine assessment.¹⁵ The difference is the position of the pelvis. The supine position eliminates lumbar lordosis, whereas the lateral tests the normal dynamic pelvic inclination. Pelvic inclination may affect testing and both positions are helpful in evaluation.

FIGURE 1-16 Flexion, adduction, internal rotation (FADDIR). A, In the lateral position, the examiner brings the examined hip into flexion, adduction, and internal rotation while monitoring the superior aspect of the hip (arrows). B, FADDIR can also be performed in the supine position (arrows).

The lateral rim impingement Test is performed with the hip passively abducted and externally rotated (Fig. 1-17). The examiner cradles the patient’s lower leg with one arm and monitors the hip joint with the opposing hand. The examiner passively brings the affected hip through a wide arc from flexion to extension in continuous abduction while externally rotating the hip. Reproduction of the patient’s pain is scored positive. If the feeling of guarding or instability is present, the test is positive for apprehension, which is not to be confused with coup-contrecoup. The traditional Patrick test is performed in the supine position and is helpful for differentiating hip and back pain. However, when performed in the lateral position, the lateral rim impingement test is useful for the detection of posterior or lateral impingement. Any type of re-creation of a posterior or lateral rim complaint can be precipitated in this position. The lateral rim impingement, FABER, and posterior rim impingement tests all place the hip into positions of posterior and lateral impingement. The lateral rim impingement test establishes a functional lumbar lordosis, with a clear ability to comfortably monitor sites of impingement, which aids in the separation of posterior and lateral points of impingement.

FIGURE 1-17 Lateral rim impingement test. A, Front view. B, Rear view. The lateral rim impingement test is performed in the lateral position. The examiner cradles the patient’s lower leg with one arm and monitors the hip joint with the opposing hand. The affected hip is passively brought through a wide arc from flexion to extension in continuous abduction while externally rotating the hip (arrows).

Prone Examination

The prone examination (Table 1-6) involves palpation of four distinct areas—the supra-SI, SI, gluteus maximus, and spine (facets). Should the pain be identified in the supra-SI joint region in or about the facet, a lumbar hyperextension test can help identify the exact location of suspected pain. If this test is positive, the patient can then be placed into a supine position, with the knees flexed. If this helps alleviate the pain, the back should be evaluated further.

TABLE 1-6 Prone Examination

See video.

The femoral anteversion test, traditionally known as Craig’s test, will give the examiner an idea of femoral anteversion and retroversion (Fig. 1-18A).¹⁶ With the patient in the prone position, the knee is flexed to 90 degrees and the examiner manually rotates the leg while palpating the greater trochanter. The greater trochanter is positioned so that it protrudes most laterally, thereby placing the femoral head into the center portion of the acetabulum. Femoral version is assessed by noting the angle between the axis of the tibia and an imaginary vertical line. Normally, femoral anteversion is between 10 and 20 degrees.¹⁶ This test will help identify cases of retroversion. If there is a significant difference of internal rotation in the extended and seated (flexed) positions, an osseous versus a ligamentous cause should be differentiated (see Fig. 1-18B). The rectus contracture test (also known as Ely’s test) is performed with the patient in the prone position and the lower extremity flexed toward the gluteus maximus (see Fig. 1-18C). Any raise of the pelvis or restriction of hip flexion is indicative of rectus femoris contracture.

FIGURE 1-18 A, Femoral anteversion test. The knee is flexed to 90 degrees and the examiner manually rotates the leg while palpating the greater trochanter. The examiner positions the greater trochanter so that it protrudes most laterally, noting the angle between the axis of the tibia and an imaginary vertical line. B, Internal rotation in the extended position. Note any differences from the seated flexed position. C, Rectus contracture test. The lower extremity is flexed toward the gluteus maximus. Any raise of the pelvis or restriction of hip flexion motion is indicative of rectus femoris contracture.

Specific Tests

Seated Piriformis Stretch Test – (Figure 1-19).

The seated position offers a stable and reproducible platform with the hip at 90° of flexion. The examiner extends the knee and passively moves the flexed hip into adduction with internal rotation while palpating 1cm lateral to the ischium (middle finger) and proximally at the sciatic notch (index finger). A positive test is the recreation of the posterior pain. Freiberg has described sciatic nerve entrapment by the piriformis¹⁷ and may be entrapped in other areas which is best described as Deep Gluteal Syndrome¹⁸. Pain in the buttock may be caused from entrapment of the sciatic nerve by the piriformis muscle, hamstring, obturator internus/gemelli complex, or scar tissue. Piriformis syndrome is often due to scarring between the sciatic nerve and external rotators¹⁹. The inferior gluteal nerve, inferior gluteal artery and sciatic nerve may be scarred into the hamstring tendons due to trauma or avulsion of the hamstring²⁰. Irritation of the structures of the obturator internus/gemelli complex are commonly overlooked in association with back pain and may cause sciatica-like pain^21,22. The use of palpation of the involved anatomy along with a physical exam that includes the Straight Leg Raise Test, the Seated Piriformis Stretch Test, and Pace’s test will aid in the differential diagnosis of deep gluteal syndrome.

FIGURE 1-19 Seated Piriformis Stretch Test. The patient is in the seated position with knee extension. The examiner passively moves the flexed hip into adduction with internal rotation while palpating 1cm lateral to the ischium (middle finger) and proximally at the sciatic notch (index finger).

RADIOGRAPHIC ANALYSES

Evaluation by Standing Anteroposterior and Frog-Leg Lateral Views

To evaluate patients who present with hip pain fully, the following radiographic views are obtained—a standing and supine anteroposterior (AP) pelvic and frog-leg lateral view.²⁵ Each radiographic view is critical in the diagnostic evaluation and treatment of structural abnormalities. There are a number of other radiographic views available, such as cross-table lateral,²⁶ false profile,^27,28 and 45- and 90-degree Dunn views,²⁹ which physicians may prefer on an individual basis.³⁰

The standing AP radiograph (Fig. 1-20) is made with the patient standing with the feet in neutral rotation and shoulder width apart to resemble the natural biomechanical stance as related to gait. The feet may also be placed parallel to each other, with enough internal rotation for the feet to touch.³¹ The x-ray tube-to-film distance should be 120 cm, with the crosshairs centered on the midpoint between the superior border of the pubic symphysis and a line drawn connecting the anterior superior iliac spines (ASISs).³⁰ The coccyx should be centered in line with the pubic symphysis, and the iliac wings, obturator foramina, and radiographic teardrops should be symmetrical in appearance. If pelvic inclination is appropriate, a 1- to 3-cm gap should be seen between the superior border of the pubic symphysis and the tip of the coccyx.³² This particular radiograph is used because acetabular roof obliquity, center edge angle, and minimum joint space width may vary between weight-bearing and supine positions.³³ Ensuring symmetry is critical to the interpretation of radiographic findings.

FIGURE 1-20 The standing AP radiograph is made with the patient standing with the feet in neutral rotation and shoulder width apart in stance. The coccyx should be centered in line with the pubic symphysis, and the iliac wings, obturator foramina, and radiographic teardrops should be symmetrical in appearance. If pelvic inclination is appropriate, a 1- to 3-cm gap should be seen between the superior border of the pubic symphysis and the tip of the coccyx.

The standing AP radiograph will assess the following: (1) functional leg length inequalities; (2) neck shaft angle (NSA); (3) femoral neck trabecular patterns; (4) lateral and anterior center edge angles; (5) acetabular inclination; (6) joint space width; (7) lateralization; (8) head sphericity; (9) acetabular cup depth; and (10) anterior and posterior wall orientation (Fig. 1-21).

FIGURE 1-21 The standing AP radiograph will assess 1 functional leg length inequalities, 2 neck shaft angle, 3 femoral neck trabecular patterns, 4 acetabular inclination, 5 lateral center edge angles, 6 joint space width, 7 lateralization, 8 head sphericity, 9 acetabular cup depth, and 10 anterior and posterior wall orientation.

Pathologic Definitions of Radiographic Findings

Functional Leg Lengths.

These should be considered when a patient presents with hip-related symptoms. The total length of one leg should be compared with the contralateral leg length by examining the superior border of the iliac crests. A leg length discrepancy (LLD) of more than 2.0 cm can have an adverse effect on the kinematic function of the hip.³⁴ The difference in functional leg lengths is usually a combination of structural differences of the long bones, hemipelvis, or spine.

Neck Shaft Angle.

The NSA dictates the load transfer from the femur to the acetabulum. It is the angle formed by the longitudinal axes of the femoral neck and the proximal femoral diaphyseal axis.³⁵ One line is drawn parallel to the midpoint of the femoral neck and one is drawn parallel to the midpoint of the femoral shaft. The angle formed represents the NSA. Normal values range from 125 to 140 degrees. If the NSA is more than 140 degrees, it is classified as coxa valgus; if less than 125 degrees, it is classified as coxa varus. The normal neck shaft angle produces the lowest stress on the femoral neck and acetabulum because of the orientation of an optimal lever arm that produces a mechanical advantage for biomechanical function.

Trabecular Pattern.

This is examined radiographically to visualize the influence of the neck shaft angle on the compressive and tensile forces within the femoral neck. In cases of coxa varus, tensile trabeculae are more prominent, whereas in cases of coxa valgus, compressive trabeculae are more prominent (Fig. 1-22).³⁶

FIGURE 1-22 A, The trabecular pattern is examined radiographically to visualize the influence of the neck shaft angle on the compressive and tensile forces within the femoral neck. This pattern is normal. In cases of coxa varus (B), tensile trabeculae are more prominent, whereas in cases of coxa valgus (C), compressive trabeculae are more prominent.

(From Pauwels F. Biomechanics of the Normal and Diseased Hip. New York: Springer-Verlag; 1976.)

Lateral Center Edge Angles.

Lateral center edge angles (LCAs) are used to assess the degree of acetabular coverage of the femoral head. The lateral center edge angle is formed by a line drawn parallel to the longitudinal pelvic axis and a line connecting the center of the femoral head with the lateral edge of the acetabulum.³⁷ Normal values range from 22 to 42 degrees in adults, although values less than 26 degrees may indicate inadequate coverage of the femoral head (Fig. 1-23).^34,38

FIGURE 1-23 Center edge (CE) angle. The vertical line is perpendicular to the horizontal line extending from the center of each femoral head (C₁ and C₂). The E (edge) point is the most lateral point of the acetabulum. The CE angle is measured between the vertical and the line passing through C₁ or C₂ and E.

(Redrawn from Delaunay S, Dussault RG, Kaplan PA, Alford BA. Radiographic measurements of dysplastic adult hips. Skeletal Radiol. 1997;26:75-81.)

Anterior Center Edge Angles.

Anterior center edge angles (ACEs) are assessed from a false profile view and are determined if there is dysplasia to help locate acetabular overcoverage.^26,39,40 The false profile view is performed with the patient standing with the affected hip against the cassette and pelvis rotated 65 degrees in relation to the wall stand. The foot on the same side as the affected hip is placed parallel to the cassette. The central beam is centered on the femoral head with a tube-to-film distance of 120 cm. A vertical line and a line connecting the center of the femoral head with the anterior edge of the acetabulum form the ACE. In consideration for intertrochanteric osteotomy (ITO) and periacetabular osteotomy (PAO), an abducted internal rotation radiograph allows for the examination of the centralization of the femoral head with improved acetabular coverage.

Acetabular Inclination.

This is the angle (Tonnis angle of inclination)³⁵ formed by a horizontal line and a tangent from the lowest point of the sclerotic zone of the acetabular roof to the lateral edge of the acetabulum (Fig. 1-24). Three classifications are used for acetabular inclination^30,41:

1. Normal = Tonnis angle of 0 to 10 degrees

2. Increased = Tonnis angle > 10 degrees, subject to structural instability

3. Decreased = Tonnis angle < 0 degrees, subject to pincer-type femoroacetabular impingement (FAI)

FIGURE 1-24 Standing AP radiograph. Joint space width (JSW; arrows) is measured as the shortest distance between the femoral head surface and acetabulum, both centrally and laterally, at the weight-bearing sclerotic zone. The acetabular index (AI) is the angle formed by a horizontal line and a tangent from the lowest point of the sclerotic zone of the acetabular roof to the lateral edge of the acetabulum. If the medial aspect of the femoral head is >10 mm from the ilioischial line, the hip is classified as lateralized (L); it is classified as nonlateralized if the medial aspect of the femoral head is within a 10-mm margin from the ilioischial line. The femoral head is classified as spherical if the epiphysis does not extend beyond the margin of a reference circle by more than 2 mm and aspherical if it does extend beyond this 2-mm margin.

Joint Space Width.

This is measured as the shortest distance between the femoral head surface and acetabulum, centrally and laterally, at the weight-bearing sclerotic zone (see Fig. 1-24). Joint space width is examined using the standing AP radiograph because the effects of position influence the joint space observed.⁴² Any evidence of joint space narrowing can be classified using the Tonnis grade for osteoarthritis.³⁵ The Tonnis grade⁴¹ for osteoarthritis can be correlated using all radiographic views, but the final grade is determined on the basis of the single view with the highest overall degree of osteoarthritic change.³⁰

Hip Center Position.

If the medial aspect of the femoral head is more than 10 mm from the ilioischial line, the hip is classified as lateralized and nonlateralized if the medial aspect of the femoral head is within a 10-mm margin from the ilioischial line. Comparisons from side to side may help determine any amount of lateralization (see Fig. 1-24).

Head Sphericity.

This should be assessed on standing AP and frog-leg lateral radiographs because a patient may have an apparently spherical head on the AP view, but not on the lateral view. The femoral head is classified as spherical if the epiphysis does not extend beyond the margin of a reference circle by more than 2 mm and is classified as aspherical if it extends beyond this 2-mm margin (see Fig. 1-24).^43,44

Acetabular Cup Depth.

The relationship of the floor of the fossa acetabuli and femoral head are evaluated relative to the ilioischial line. If the floor of the fossa acetabuli touches or is medial to the ilioischial line, or the posterior wall extends lateral to the center axis of rotation, the hip is classified as coxa profunda. If the medial aspect of the femoral head is medial to the ilioischial line, the head is classified as protrusio.⁴⁵ Also, the inner acetabular wall thickness, medial wall shape, and inferior cup orientation should be recognized.

Acetabular Version.

Acetabula can be classified as anteverted or retroverted based on the presence or absence of a crossover sign (Fig. 1-25).⁴⁶ The acetabulum is classified as anteverted if the line of the anterior aspect of the rim does not cross the line of the posterior aspect of the rim before reaching the lateral aspect of the sourcil. If the anterior aspect of the rim does cross the line of the posterior aspect of the rim before reaching the lateral edge of the sourcil, the acetabulum is classified as retroverted. It is important to note that true acetabular retroversion is associated with a deficient posterior wall,⁴⁶ whereas a hip with a crossover sign but no posterior wall deficiency refers to anterior overcoverage—cranial acetabular retroversion or anterior focal acetabular retroversion.^30,47 Both standing and supine AP radiographs should be used to determine anterior and posterior wall inclination, again ensuring good quality because of the possibility of overinterpreting the incidence of retroversion.³³

FIGURE 1-25 Acetabula can be classified as anteverted or retroverted based on the presence or absence of a crossover of the anterior wall (AW) and posterior wall (PW). The inner acetabular wall thickness, medial wall shape, and inferior cup orientation should be recognized.

(From Tannast M, Siebenrock KA, Anderson SE. Femoroacetabular impingement: radiographic diagnosis—what the radiologist should know. AJR Am J Roentgenol. 2007;188:1540-1552)

Frog-Leg Lateral Radiograph.

This allows for the assessment of another view of medial and lateral joint space width, femoral head sphericity, congruency, head-neck offset, alpha angle, and bone morphology (Fig. 1-26). The frog-leg lateral radiograph should be taken with the patient supine, the affected limb flexed at the knee approximately 30 to 40 degrees, and the hip abducted to 45 degrees. The heel should rest against the medial aspect of the contralateral knee. The cassette is placed so that the top of the film rests at the ASIS and the crosshairs directed midway between the ASIS and pubic symphysis. The x-ray tube-to-film distance should be approximately 102 cm. This particular orientation is used because it is easily reproducible in the operating room and allows for a consistent radiographic view of the head-neck junction offset during the pre- and intraoperative radiographic examination.

FIGURE 1-26 The 30-degree frog-leg lateral radiograph allows for the assessment of another view of medial and lateral joint space width, femoral head sphericity, congruency, head-neck offset, and alpha angle (AA), as well as bone morphology. The femoral head is classified as spherical if the epiphysis does not extend beyond the margin of a reference circle by more than 2 mm and aspherical if it does extend beyond this 2-mm margin. A prominence is shown on the femoral neck where the top line intersects the reference circle.

Head-Neck Offset.

This is assessed from the frog-leg lateral radiograph and is classified based on the gross appearance of the relationship between the radius curvatures of the anterior aspect of the femoral head with the posterior aspect of the head neck junction.⁴³ The head-neck offset is classified as symmetrical if the anterior and posterior concavities are grossly symmetrical. If the anterior concavity has a radius of curvature greater than that at the posterior aspect of the head-neck (H-N) junction, it is classified as having a moderate decrease in H-N offset. If the anterior aspect has a convexity, as opposed to a concavity, the head-neck junction is classified as having a prominence (CAM-type FAI).⁴³

Alpha Angle.

This is calculated by drawing a line from the center of the femoral head to the point on the anterolateral aspect of the head-neck junction where the radius of the femoral head deviates from the more central femoral head radius in the acetabulum, or where a prominence starts, and a line drawn through the center of the femoral neck to the center of the femoral head (see Fig. 1-26). Values of more than 42 degrees are suggestive of head-neck offset deformity,³⁰ but are dependent on acetabular femoral congruency.³⁴

Cross-Sectional Imaging Techniques

The use of cross-sectional imaging (Fig. 1-27) is essential for the evaluation of patients for intra- and extra-articular pathology. Imaging protocols such as magnetic resonance imaging (MRI), magnetic resonance arthrography (MRA),⁴⁸ multidetector computed tomography (MDCT),³⁴ and computed tomography (CT)⁴⁹ allow for the assessment of basic structural torsional alignment that give rise to or predispose patients to certain types of pathology such as FAI, acetabular tears, or articular damage.

FIGURE 1-27 MDCT is useful for assessing osseous structures and surrounding soft tissues of the hip and acetabulum. It provides data that have the same resolution in the longitudinal axis (z axis) as in the x or y axis. Oblique axial T1-weighted MR image shows the alpha angle (white arc), which is calculated by drawing a line down the center of the femoral head and neck (white arrow) and a circle around the periphery of the femoral head (black arrowhead). A second line is drawn from the femoral head center, where the anterior osseous femur intersects the circle drawn around the femoral head (black arrow). Normal values are <55 degrees.

(From Beall DP, Martin HD, Mintz DN, et al. Anatomic and structural evaluation of the hip: a cross-sectional imaging technique combining anatomic and biomechanical evaluations. Clin Imaging. 2008; 32:372-381.)

The McKibbin instability index can be calculated from MRI scans and is based on the assumption that the effects of femoral and acetabular anteversion may be additive or may offset each other. It is calculated as the sum of the angles of femoral and acetabular anteversion, with an index of 60 denoting severe instability. Deviation is classified as ranging from grade −3, for a low instability index of less than 20, to grade +3, for a high instability index of more than 50.⁵⁰ For this technique, the feet should be pointing straight ahead and held in place by a brace or tape to ensure that the geometric relationship of the acetabulum and femur are properly evaluated.

MDCT (see Fig. 1-27) is useful for assessing osseous structures and surrounding soft tissues of the hip and acetabulum and provides data that have the same resolution in the longitudinal axis (z axis) as in the x or y axis.³⁴ This relationship is important to understand because of the potential not only to detect anatomic derangements that may allow movements that create primary pathology, but also to correct the underlying anatomic abnormalities that may predispose the patient to recurrent or persistent pathology.

MRA (Figs. 1-28 and 1-29) provides assistance in the evaluation of intra-articular pathology of the hip. The detection of acetabular labral tears may assist in confirming a decision for arthroscopic surgery and has been reported to have a positive predictive value of 93%.⁵¹ MRA may also be helpful in the evaluation of mild osseous abnormalities, such as acetabular retroversion and reduced head-neck offset, the integrity of the acetabular labrum, and articular cartilage surface. The ability to detect these subtle abnormalities accurately may be affected by the technique and experience of the radiologist and by the quality of scanner used for imaging. Research using delayed gadolinium-enhanced magnetic resonance imaging of cartilage (dGEMRIC), which measures the loss of glycosaminoglycans in the early stages of arthritis, has demonstrated that dGEMRIC can detect early stages of osteoarthritis caused by hip dysplasia and femoroacetabular impingement.⁵²

FIGURE 1-28 Axial gradient echo MR image of the knees taken from a tri-plane localizer sequence shows the coronal reference line (white arrows) and the posterior intercondylar line (white line with black shadowing indicated by the black arrows). The amount of internal or external rotation is then compared with the coronal reference line and the overall amount of femoral version is calculated. For example, if the proximal femur shows 3 degrees of external rotation and the distal femur shows 15 degrees of internal rotation, the amount of anteversion of the femur is 18 degrees (from 3 degrees external rotation proximally to 15 degrees of internal rotation distally). Foot rotation must be controlled by bracing or taping between the two images.

(From Beall DP, Martin HD, Mintz DN, et al. Anatomic and structural evaluation of the hip: a cross-sectional imaging technique combining anatomic and biomechanical evaluations. Clin Imaging. 2008;32:372-381.)

FIGURE 1-29 Coronal T2-weighted MRI scan with fat saturation taken after direct arthrographic injection with gadolinium shows thickening of the ligamentum teres femoris (large white arrows) and of the ligamentous junction between the ligamentum orbicularis and the iliofemoral ligament (white arrowhead). The femoral head is slightly displaced laterally in relation to the lateral osseous edge of the acetabulum (small white arrow), resulting in some uncovering of the lateral femoral head.

(From Beall DP, Martin HD, Mintz DN, et al. Anatomic and structural evaluation of the hip: a cross-sectional imaging technique combining anatomic and biomechanical evaluations. Clin Imaging. 2008;32:372-381.)

PEARLS& PITFALLS

PEARLS

1. Use a structured physical examination and standardized technique.

2. Ensure quality standardized AP and lateral radiographic examinations.

3. Understand the torsional alignment of femur and acetabulum by MRI or CT techniques.

4. Perform specific additional ancillary tests, as needed.

5. Prior to surgical consideration note internal rotation, external rotation, femoral version, acetabular version, neck shaft angle, acetabular index, center edge, and functional score (HHS).

PITFALLS

1. Poor quality physical or radiographic exams lead to misinterpretations.

2. Using only two views to analyze dynamic three-planar hip pathology is incomplete. The third axis must be evaluated to understand the complexity of hip biomechanics.

3. Variations in terminology and technique for descriptive tests lead to communication and testing difficulties.

SUMMARY AND CONCLUSIONS

As our understanding of hip pathology advances, the physical examination of the hip continues to evolve. To understand the findings fully, one must be familiar with the anatomy and biomechanics of the hip joint. The use of a formalized, reproducible physical examination will help identify and distinguish osseous, musculotendinous, and ligamentous abnormalities and their comorbidities in a timely fashion (Fig. 1-30). Radiographs and cross-sectional imaging techniques, together with a standardized physical examination, will aid in the preoperative, intraoperative, and postoperative assessment of the hip. The physical examination of the hip is also used as a guide to monitor physical therapy and postoperative rehabilitation. This chapter has introduced a framework of discussion regarding clinically and biomechanically relevant physical examinations.

FIGURE 1-30 Physical examination of the hip—intake form.

ACKNOWLEDGMENTS

I would like to thank Shea A. Shears, Aaron M. Smathers, Ian J. Palmer, and all the members of the MAHORN (Multicenter Arthroscopy of the Hip Outcomes Research Network) Group who were instrumental in the development of this chapter.