Clinical Examination and Imaging of the Hip

CHAPTER 1 Clinical Examination and Imaging of the Hip



The clinical examination of the hip is a comprehensive assessment of osseous, ligamentous, and musculotendinous tissues. To appreciate this achievement of symphonic function, it is important to understand the balance and interrelationships of each system with the other in a static and dynamic fashion. Imaging of the hip is a powerful tool for the visualization and quantification of the structures within and about the hip joint. Imaging techniques continue to evolve as our understanding of pathologic hip conditions advances. Optimally, the hip will be recognized early as the source of the complaint, which is dependent on a consistent method of interpreting the history, clinical examination, and imaging of the hip. The goal of this chapter will be to describe in detail how to perform the clinical examination of the hip and explain why these tests are important, raise awareness for commonly found but uncommonly recognized conditions, and describe the current methodologies for accurate diagnostic imaging.



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.



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.



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.




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).



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







See video for performing supine examination tests.


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



































Range of Motion Assessment Normal (degrees) Abnormal (degrees)
Seated internal rotation 20-35 <20
Seated external rotation 30-45 <30
Extended internal rotation 20-35 <20
Extended external rotation 30-45 <30
Supine hip flexion 100-110 <100
Adduction 20-30 <20
Abduction 45 <45



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.



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).



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).



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.



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. 1-11

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Jun 19, 2016 | Posted by in MUSCULOSKELETAL MEDICINE | Comments Off on Clinical Examination and Imaging of the Hip

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