Hip
The hip joint is one of the largest and most stable joints in the body. If it is injured or exhibits pathology, the lesion is usually immediately perceptible during walking. Because pain from the hip can be referred to the sacroiliac joints or the lumbar spine, it is imperative—unless there is evidence of direct trauma to the hip—that these joints be examined along with the hip.
Applied Anatomy
The hip joint is a multiaxial ball-and-socket joint that has maximum stability because of the deep insertion of the head of the femur into the acetabulum (Figure 11-1). The femoral head is much more stable in the acetabulum for the hip than the humerus is in the glenoid for the shoulder. To allow sufficient movement and proper alignment to occur at the hip joint, the femur has a longer neck than the humerus and is anteverted (Figure 11-2).
A, The right hip opened to show its internal components. B, Side view of right innominate bone (pelvis) showing muscle attachments. (Modified from Neumann DA: Kinesiology of the musculoskeletal system—foundations for physical rehabilitation, St Louis, 2002, CV Mosby, pp. 388, 397.)
In addition, the hip, like the shoulder, has a labrum, which helps to deepen and stabilize the joint.1,2 The acetabular labrum increases the articular surface area of the acetabulum and volume, and it creates a seal for the central compartment, which is part of the intra-articular hip joint. The seal resists distraction of the femoral head from the socket by maintaining a negative pressure and resists fluid flow that enhances nutrition of the hip articular cartilage, which in turn provides a smooth gliding surface.3,4 The joint has a strong capsule and very strong muscles that control its actions (Figure 11-3). The acetabulum is formed by fusion of part of the ilium, ischium, and pubis, which taken as a group are sometimes called the innominate bone or pelvis. The acetabulum opens outward, forward, and downward. It is half of a sphere, and the femoral head is two thirds of a sphere. The hip, already a stable joint because of its bony configuration, is supported by three strong ligaments: the iliofemoral, the ischiofemoral, and the pubofemoral ligaments (Figure 11-4). The iliofemoral ligament (Y ligament of Bigelow) is considered to be the strongest ligament in the body. It is positioned to prevent excessive extension and plays a significant role in stabilizing and in maintaining upright posture at the hip while limiting anterior translation. The acetabular labrum plays a secondary role in stabilizing the hip during lateral rotation while preventing anterior translation.5 The ischiofemoral ligament, the weakest of these three strong ligaments, winds tightly on extension, helping to stabilize the hip in extension. The pubofemoral ligament prevents excessive abduction of the femur and limits extension. All three ligaments also limit medial rotation of the femur. A fourth ligament of the hip that sometimes is injured is the ligamentum teres or “ligament of the head,” which provides a physical attachment of the head of the femur to the acetabulum.6
Under low loads, the joint surfaces are incongruous; under heavy loads, they become congruous, providing maximum surface contact. The maximum contact brings the load per unit area down to a tolerable level. Depending on the activity, the forces exerted on the hip will vary.7
When considering movement or kinematics at the hip joint, one must consider whether the pelvis is moving on stationary femur (weight-bearing) or the femur (non–weight-bearing) is moving on the pelvis (Figure 11-5).
Femoral-on-pelvic and pelvic-on-femoral rotations occur in three planes. The axis of rotation for each plane of movement is shown as a colored dot, located at the center of the femoral head. A, Side view shows sagittal plane rotations around a medial-lateral axis of rotation. B, Front view shows frontal plane rotations around an anterior-posterior axis of rotation. C, Top view shows horizontal plane rotations around a longitudinal, or vertical, axis of rotation. (From Neumann DA: Kinesiology of the musculoskeletal system—foundations for physical rehabilitation, St Louis, 2010, Mosby, p. 477.)
Patient History
In addition to the questions listed under the “Patient History” section in Chapter 1, the examiner should obtain the following information from the patient:
2. If trauma was involved, what was the mechanism of injury? Did the patient land on the outside of the hip (e.g., trochanteric bursitis) or land on or hit the knee, thus jarring the hip (e.g., subluxation, acetabular labral tear)? Was the patient involved in repetitive loading activity (e.g., femoral stress fracture) or osteoporotic (insufficiency injury)?8 A careful determination of the mechanism of injury often leads to a diagnosis of the problem. Mechanical hip problems are reported as symptoms getting worse with activity, twisting movements are painful, sitting is uncomfortable (hip flexion), getting up from sitting may cause catching, ascending and descending stairs are difficult as is getting in and out of an automobile, and the patient may have difficulty putting on shoes and/or socks.9,10
3. What are the details of the present pain and other symptoms (Table 11-1)?11 Hip intra-articular pain, including labral tears and anterior impingement, is felt mainly in the groin and along the front or medial side of the thigh to the knee,1,12 whereas buttock pain is associated with posterior labral tears and lumbar spine problems.1,13 Adductor pain may be the result of overactive adductors caused by pelvic instability.14 Pain may also be referred to the hip area from several structures (Figure 11-6). Pain from the lumbar spine may commonly be referred to the back or lateral aspect of the hip.
A sports hernia, which is commonly caused by a deficient inguinal canal posterior wall, nerve entrapment or adductor tendonopathies, may have an insidious onset of unilateral dull, aching pain in the groin that may be sharp or burning and may radiate into the proximal thigh, low back, lower abdominal muscles, perineum and/or scrotum. The symptoms are aggravated by sudden acceleration, cutting, or kicking.15–18
Lateral hip pain may be due to a trochanteric bursitis or tear of the gluteus medius tendon, most commonly in older patients.19 Lateral hip pain may also simulate L4 nerve root pain; therefore, assessment of the back should also be considered for lateral or posterior symptoms. Hip pain may also be referred to the knee or back and may increase on walking. Clicking is common with labral tears.20,21 Snapping in and around the hip (coxa saltans) has many causes (Table 11-2). First and most commonly, it may be caused by slipping of the iliopsoas tendon over the osseous ridge of the lesser trochanter or anterior acetabulum, or the iliofemoral ligament may be riding over the femoral head.22–24 Some call this internal snapping. If due to the iliopsoas tendon or iliofemoral ligament, the snapping often occurs at approximately 45° of flexion when the hip is moving from flexion to extension, especially with the hip abducted and laterally rotated (snapping hip sign or extension test).25 The snap, which may be accompanied by pain or a jerk, is palpated anteriorly in the inguinal region.25,26 Second, the snapping may be caused by a tight iliotibial band or gluteus maximus tendon riding over the greater trochanter of the femur.22,23 This is sometimes called external snapping. This snapping or popping, which tends to be felt more lateral, occurs during hip flexion and extension, especially if the hip is held in medial rotation, and may be made worse if the trochanteric bursa is inflamed.26 The third cause of a snapping hip is acetabular labral tears or loose bodies, which may be the result of trauma or degeneration.23,27–29 This is sometimes referred to as intra-articular snapping. In this case, the patient (commonly between 20 to 40 years) complains of a sharp pain into the groin and anterior thigh, especially on pivoting movements. Passively, clicking may be felt and heard when the extended hip is adducted and laterally rotated.23,26 Each of these conditions may be referred to as snapping hip syndrome.
4. Is the condition improving? Worsening? Staying the same? Such a question gives the examiner some idea of the present state of the joint and pathology. Table 11-3 outlines criteria for osteoarthritis in patients with hip pain.30
5. Does any type of activity ease the pain or make it worse? For example, trochanteric bursitis often results from abnormal running mechanics with the feet crossing midline (increased adduction), wide pelvis and genu valgum, or running on tracks with no banking.26
8. Is there any past medical and/or surgical history, such as developmental disorders (e.g., hip dysplasia, Legg-Calvé-Perthes disease), systemic illnesses, metabolic, or inflammatory disorders?12 A history of alcohol, steroid or tobacco use can increase the risk of osteonecrosis.12
TABLE 11-1
| Type of Pain | Possible Causes |
| Dull, deep, aching | Arthritis, Paget disease |
| Sharp, intense, sudden, associated with weight bearing | Fracture |
| Tingling that radiates | Radiculopathy, spinal stenosis, meralgia paresthetica |
| Increased pain while sitting with the affected leg crossed | Trochanteric bursitis |
| Pain at sitting, legs not crossed | Ischiogluteal bursitis |
| Pain after standing, walking | Hip arthrosis |
| Pain on attempted weight bearing | Occult fracture, severe arthrosis |
| Unremitting, long duration | Paget disease, metastatic carcinoma, severe arthrosis (occasionally) |
From Schon L, Zuckerman JD: Hip pain in the elderly: evaluation and diagnosis. Geriatrics 43:58, 1988.
TABLE 11-2
Causes of Snapping Hip (Coxa Saltans) Symptoms
From Wahl CJ, Warren RF, Adler RS, et al: Internal coxa saltans (snapping hip) as a result of overtraining. Am J Sports Med 32:1303, 2004.
TABLE 11-3
Classification Criteria for Osteoarthritis of the Hip
| Clinical (history, physical examination, laboratory) classification criteria for osteoarthritis of the hip, classification tree format* | |
| Combined clinical (history, physical examination, laboratory) and radiographic classification criteria for osteoarthritis of the hip, traditional format** | Hip pain, and at least two of the following three features: |
ESR, Erythrocyte sedimentation rate (Westergren).
*This classification method yields a sensitivity of 86% and a specificity of 75%.
**This classification method yields a sensitivity of 89% and a specificity of 91%.
Modified from Altman R, Alarcon G, Appelrouth D, et al.: The American College of Rheumatology criteria for the classification and reporting of osteoarthritis of the hip. Arth Rheum 34:511–512, 1991.
Observation
As the patient comes into the assessment area, the gait should be observed. If the hip is affected, the weight is lowered carefully on the affected side and the knee bends slightly to absorb the shock. The length of the step on the affected side is shorter so that weight can be taken off the leg quickly. If the hip is stiff, the entire trunk and affected leg swing forward together. It is also important to watch for “balance” of the pelvis on the hip. In standing, the patient commonly has the hip slightly flexed if there is pain in the hip.
Pathology in the hip region can lead to tight adductors, iliopsoas, piriformis, tensor fasciae latae, rectus femoris, and hamstrings while, at the same time, the gluteus maximus, medius, and minimus become weak.31,32 Weak abductors can lead to a Trendelenburg gait or an “abductor lurch.” Internal hip pathology or a flexion contracture may lead to a “pelvic wink.” This is excessive rotation in the axial plane (more than 40°) toward the affected hip in an attempt by the patient to obtain terminal hip extension.33 If there is an imbalance of the flexors or extensors in the sagittal plane, the forward–backward motion of the trunk is altered to help maintain balance. For example, a bilateral hip flexion contracture causes the lumbar spine to extend to a greater degree (increased lordosis) as a compensating mechanism. Weak extensors cause the patient to move the trunk backward to maintain balance and avoid falling as a result of the unopposed action of the flexors. If the lateral rotators are significantly stronger than the medial rotators, as is normally the case, excessive toe-out can result. In addition, the patellae may have a “frog eyes” appearance (turn-out). Contracture of either of the rotators may lead to a pivoting at the hip during gait.34 The different types of gait are discussed in greater detail in Chapter 14.
If the patient uses a cane, it should be held in the hand opposite the affected side to negate some of the force of gravity on the affected hip.35 The use of a cane can decrease the load on the hip by as much as 40%.35,36
The patient should be standing and suitably undressed for the examiner to perform a proper observation. The following aspects are noted from the front, side, and behind:
1. Posture: The examiner should watch for pelvic obliquity caused by, for example, unequal leg length, muscle contractures, or scoliosis (see Chapter 15 for more details). It must be remembered that injury to iliopsoas may also affect the spine. Therefore, when asking patients to do movements involving these muscles, the examiner must watch the effect on the spine and spinal movement (see the “Thomas Test” section later in this chapter). Tightness of the iliopsoas can cause deviation of the spine to the same side.37
3. Balance: It is important to check the patient’s proprioceptive control in the joints being assessed. This control may be evaluated by asking the patient to balance first on one leg (the good one) and then the other leg—first with the eyes open, and then with the eyes closed. Differences should be noted through comparison. Loss of proprioceptive control is especially obvious when the patient’s eyes are closed. The use of the stork standing test34 (Figure 11-7) has also been advocated for testing proprioception. This test may also test stability at the sacroiliac joints, the knee, and the ankle and foot. With both methods, the examiner should watch for a positive Trendelenburg sign, which would negate the proprioceptive tests.
5. Any obvious shortening of a leg: Shortening of the leg may be demonstrated by a spinal scoliosis if the shortening is present in only one lower limb. Shortening may be structural or functional. Structural changes at the hip that may lead to altered limb length include hip angulation deformity, congenital hypoplasia, femoral growth plate problems and developmental disorders.12 If the hips are unstable (e.g., bilateral unreduced congenital dislocation of the hip [CDH]), an increased lumbar lordosis may be evident because the head of the femur usually rests above and behind the acetabulum, causing the patient to have an increased lordosis to maintain the center of gravity.
6. Color and texture of the skin
8. The patient’s willingness to move: If the hip is painful, the patient has an antalgic gait (see Chapter 14) and does not want to move the hip. If the hip is unstable, the patient has more difficulty controlling its movement.
Anterior View
The examiner should note any abnormality of the bony and soft-tissue contours. With many patients, differences in these contours are difficult to detect because of muscle bulk and other soft-tissue deposition around the hips. The examiner must, therefore, look closely. The same is true for swelling. Swelling in the hip joint itself is virtually impossible to detect by observation, and swelling resulting from a psoas or trochanteric bursitis can easily be missed if the examiner is not carefully observant.
Lateral View
While the patient is viewed from the side, the contour of the buttock should be observed for any abnormality (gluteus maximus atrophy or atonia). In addition, a hip flexion deformity is best observed from this position. The examiner should take the time to compare the two sides and note any subtle differences.
Posterior View
The position of the hip and the effect, if any, of this position on the spine should be noted. For example, a hip flexion contracture may lead to an increased lumbar lordosis. Any differences in bony and soft-tissue contours should again be noted.
Examination
When doing an examination of the hip, the examiner must keep in mind that pain may be referred to the hip from the sacroiliac joints or the lumbar spine, and vice versa. Therefore, the examination may be an extensive one. If there is any doubt as to the location of the lesion, an assessment of the lumbar spine and sacroiliac joints should be performed along with the hip. It is only through a careful examination of the three areas, especially if there has been no history of trauma, that the examiner can discern the location of the lesion.
As with any examination, the examiner should compare one side of the body with the other, noting any differences. This comparison is necessary because of the individual differences among normal people.
Active Movements
The active movements (Figure 11-8) are done in such a way that the most painful ones are done last. To keep movement of the patient to a minimum, some movements are tested with the patient in the supine position, and others are tested in the prone position. For ease of description, the movements are described together. The examiner should follow the order as stated in the précis at the end of the chapter when examining the patient. If the history has indicated that repetitive movements, sustained postures, or combined movements have caused symptoms, the examiner should ensure that these movements are tested as well. For example, sustained extension of the hip may provoke gluteal pain in the presence of claudication in the common or internal iliac artery.38 During the active movements, the examiner should always watch for the possibility of muscle or force-couple imbalances that lead to abnormal muscle recruitment patterns. For example, during extension, the normal pattern is contraction of the gluteus maximus followed by the erector spinae on the opposite side and the hamstrings (depending on the load being extended). If the erector spinae contract first, the pelvis rotates anteriorly and hyperextension of the lumbar spine occurs. When doing the active movements, the examiner should watch the pelvis and the anterior superior (supine) and posterior superior (prone) iliac spines. During hip movement, if the pelvic force-couples are normal, the pelvis and anterior superior iliac spine (ASIS)/posterior superior iliac spine (PSIS) will not move. If they do, it may be an indication of muscle imbalance (Figure 11-9).
Figure 11-8 Active movements of the hip.A, Flexion. B, Extension. C, Abduction. D, Adduction. E, Rotation in the supine position. F, Rotation in the prone position. (A, E, and F, Redrawn from Beetham WP, Polley HF, Slocumb CH, et al: Physical examination of the joints, Philadelphia, 1965, WB Saunders, pp. 134, 137, and 138, respectively.)
A, With normal activation of the rectus abdominis and the hip flexors (psoas and rectus femoris), the pelvis is stabilized and prevented from anterior tilting by the pull of the hip flexor muscles. B, With reduced activation of the rectus abdominis, contraction of the hip flexor muscles causes a marked anterior tilt of the pelvis. Note the increase in lumbar lordosis that accompanies the anterior tilt of the pelvis. (Modified from Neumann DA: Kinesiology of the musculoskeletal system—foundations for physical rehabilitation, St Louis, 2002, CV Mosby, p. 413.)
Flexion of the hip is tested in the supine position and normally ranges from 110° to 120° with the knee flexed. If the ASIS begins to move, the movement is stopped because pelvic rotation is occurring rather than hip flexion. The patient’s knee is flexed during the test to prevent limitation of movement caused by hamstring tightness. If sharp anterior groin pain that may refer to the gluteal or trochanteric region is elicited on full flexion, adduction and medial rotation, the pain may be the result of anterior impingement of the femoral neck against the acetabular rim.39–45 The pain is made worse by certain movements (e.g., pivoting, movement into extreme rotation) or long periods of sitting, standing or walking.46 This femoroacetabular impingement (FAI) (Figure 11-10) may be cam type or pincer type. Both types are usually associated with femoral head (e.g., Legg-Calvé-Perthes disease, slipped capital femoral epiphysis) or acetabular dysplasia.47–52 The cam type impingement (see Figure 11-10, B) is commonly due to impingement of a large aspherical femoral head in a tight acetabulum. The deformed (flattened) head (pistol grip deformity or head tilt deformity) leads to shearing of the labrum and acetabular cartilage.53 The cam type impingement may also lead to increased stress at the symphysis pubis and may be a precursor to athletic pubalgia.54 Pincer type impingement (see Figure 11-10, C) is due to over coverage of the humeral head by a prominent acetabular rim (i.e., the acetabulum overhangs the femoral head due to acetabular dysplasia, acetabular retroversion, or coxa profunda) leading to pinching of the femoral neck against the labrum with the same ultimate result as the cam type degeneration of the labrum and adjacent cartilage.55–57 In the presence of acetabular retroversion or decreased femoral anteversion, hip flexion in the neutral line is limited to as little as 90° but full range is accomplished if the hip is allowed to laterally rotate and abduct. Lateral rotation may exceed 60° with medial rotation limited.49,58 The examiner should palpate the ASIS when testing hip movements. In the presence of FSI, the ASIS moves early due to limited hip flexion as the lumbar spine flexes to allow more movement.59 If medial rotation is measured at 90° flexion, medial rotation in the FSI patient will be limited.59 During the movement, if the abdominals are weak, the pelvis rotates anteriorly (see Figure 11-8). If the hip flexors are weak, the pelvis rotates posteriorly.
A, Normal hip. B, Reduced femoral head-neck offset (cam-type impingement). C, Excessive overcoverage of the femoral head (pincer-type impingement). D, Combination of cam and pincer types of impingement.
Extension of the hip normally ranges from 0° to 15°. The patient is in the prone position, and the examiner must differentiate between hip extension and spinal extension. Patients often have a tendency to extend the lumbar spine at the same time that they are extending the hip, giving the appearance of increased hip extension. Elevation of the pelvis or superior movement of the PSIS indicates the patient has passed the end of hip extension.
Hip abduction normally ranges from 30° to 50° and is tested with the patient in the supine position. Before asking the patient to do the abduction or adduction movement, the examiner should ensure that the patient’s pelvis is “balanced” or level, with the ASISs being level and the legs being perpendicular to a line joining the two ASISs. The patient is then asked to abduct one leg at a time. Abduction is stopped when the pelvis begins to move. Normally, the patient should be able to do hip abduction while the lower extremities, pelvis, trunk and shoulders remain aligned in the frontal plane.60 Pelvic motion is detected by palpation of the ASIS and by telling the patient to stop the movement as soon as the ASIS on either side starts to move. Normally, the ASIS on the movement side elevates while the opposite ASIS may drop or elevate. When the patient abducts the leg, the opposite ASIS tends to move first; with an adduction contracture, this occurs earlier in the range of movement.
If, during abduction, lateral rotation and slight flexion occurs early in the movement, the tensor fascia lata may be stronger and gluteus medius/minimus weak. If lateral rotation occurs later in the ROM, the iliopsoas or piriformis may be overactive. If the pelvis tilts up at the beginning of movement, the quadratus lumborum is overactive. All of these movements demonstrate imbalance patterns.
Hip adduction is normally 30° and is measured from the same starting position as abduction. The patient is asked to adduct one leg over the other while the examiner ensures that the pelvis does not move. An alternative method is for the patient to flex the opposite hip and knee and hold the limb in flexion with the arms; the patient then adducts the test leg under the other leg. This method is useful only for thin patients. When the patient adducts the leg, the ASIS on the same side moves first. This movement occurs earlier in the ROM if there is an abduction contracture. Adduction may also be measured by asking the patient to abduct one leg and leave it abducted; the other leg is then tested for the amount of adduction present. The advantage of this method is that the test leg does not have to be flexed to clear the other leg before doing the adduction movement.
Rotation movements may be performed with the patient supine, prone, or sitting. Medial rotation normally ranges from 30° to 40°, and lateral rotation from 40° to 60°. In the supine position, the patient simply rotates the straight leg on a balanced pelvis. Turning the foot or leg outward tests lateral rotation; turning the foot or leg inward tests medial rotation. In another supine test (see Figure 11-8, E), the patient is asked to flex both the hip and knee to 90° as the patient would do when being tested in sitting.61 When using this method, it must be recognized that having the patient rotate the leg outward tests medial rotation, whereas having the patient rotate the leg inward tests lateral rotation. With the patient prone, the pelvis is balanced by aligning the legs at right angles to a line joining the PSISs. The patient then flexes the knee to 90°. Again, medial rotation is being tested when the leg is rotated outward, and lateral rotation is being tested when the leg is rotated inward (see Figure 11-8, F). Usually, one of these last two methods (sitting or prone) is used to measure hip rotation, because it is easier to measure the angle when performing the test. However, in prone, the measurement is done on a straight leg, whereas in sitting or supine, rotation is measured with the hip flexed to 90°. It has been found that there is a difference in the amount of lateral rotation between the flexed (less) and straight position, whereas medial rotation shows little difference when measured in the two positions.61
Passive Movements
If the range of movement was not full and the examiner was unable to test end feel during the active movements, passive movements should be performed to determine the end feel and passive range of motion (PROM). The passive movements performed are the same as the active movements. All the movements except extension can be tested with the patient in the supine lying position.
Sutlive et al.62
