The physician's history, examination, and diagnostic studies determine the patient's diagnosis and prognosis of surgical or nonsurgical treatment. The patient's history and the clinical evaluation assist in determining how the symptoms will respond to treatment. A course of presurgical treatment (prehab) may be indicated in some hip cases to regain neuromotor control and decrease stresses to the joint. An appropriate exercise program can, at times, help restore normal mechanics and minimize joint stresses to facilitate healing. In other circumstances, it can buy time when a patient desires and the physician thinks it is beneficial to delay operative intervention. Rehabilitation of a patient preoperatively when the need for surgery has been confirmed better prepares patients psychologically and physically for postsurgical recovery.
Pathomechanics of the hip and pelvis are viewed as primarily reflecting the joint pathology and secondarily reflecting joint compensation. For example, for a patient with degenerative changes within the joint, the primary disorder is the antalgic gait caused by joint pain. Secondary dysfunction may ensue due to weakness of the gluteus medius, presenting as an abductor lurch (Trendelenburg's gait). Disorders of the sacroiliac joint (S-I joint) and lumbar spine also become considerations with chronic hip dysfunction because of altered gait and weight-bearing mechanics (Figures 17.1, 17.2).
The hip allows multidirectional mobility (Figure 17.3). Most activities do not occur in a specific plane but require combinations of movement. Activities of daily living such as sitting, walking, stair climbing, running, and squatting all require different functional ranges of motion. Common functional deficits include pain with prolonged sitting; difficulty donning socks or shoes; inability to squat or sit on low surfaces; and altered gait with a shortened stance phase, protraction
of the hip, and decreased hip extension on the involved side. Normal gait uses multiplanar hip motion of 15 degrees of extension, 37 degrees of flexion, 7 degrees of abduction, 5 degrees of adduction, 4 degrees of internal rotation, and 9 degrees of external rotation4 (Figure 17.4). Ascending stairs requires the motion of a normal walking pattern with additional 67 degrees of flexion and creates a force of three times body weight. Standing on one leg creates a force of two and one-half times, while loads approaching eight times body weight occur in the hip joint during jogging, with potentially greater loads resulting from vigorous athletic competition5 (Figure 17.5).
These parameters must be considered when assessing sports injuries and the sport-specific demands on return to competition. It is estimated that a healthy hip joint can tolerate a force of approximately 12 to 15 times body weight.6
The clinical assessment includes observation of gait and basic functional transitional movements such as sitting to standing to sitting, ascending and descending stairs, and balance activities. It also includes understanding the patient's specific movement patterns and what elicits the pain symptoms; balance testing; assessment of involvement of the lumbar spine, pelvis, sacroiliac joint, and knee; range of motion and muscle testing; palpation; and special hip tests that may be indicated for flexibility and differentiation.
Primary problems of symptomatic hip pathology may involve the soft tissue encasing the joint, the surrounding capsule, or the joint structure. The irritation and inflammation of the musculotendinous structures, bursae, or joint capsule can result in concomitant tendonitis, bursitis, or capsulitis. The ligaments of the hip joint are susceptible to acute tearing and chronic degeneration. Within the joint, labral or chondral injury can be responsible for protracted hip symptoms. Loose bodies and labral lesions are well-recognized indications for arthroscopic surgery, which tends to produce gratifying results for properly selected patients.7 The acetabular labrum is a fibrocartilaginous rim around the perimeter of the acetabulum and is triangular in cross section. The labrum is thicker postero-superiorly and thinner anteroinferiorly.8-11 The labrum is attached to the osseous rim of the acetabulum and blends with the transverse ligament at the margins of the acetabular notch. The labrum deepens the ac-etabulum and is thought to assist in the constraint of the femoral head within the bony socket.12 Several studies have described a thickening or hyperplasia of the acetabular labrum in diseased states, expecially developmental dysplasia of the hip.13-15 This finding supports the theory of the functional importance in restraint of the femoral head within the acetabulum.12 Free nerve endings and sensory organs have been found in the superficial layers of the acetabular labrum. It is believed that these free nerve endings contribute to nociceptive and proprioceptive mecha-nisms.16 The acetabular labrum may also improve the stability of the hip joint by maintaining a negative in-traarticular pressure.17
The clinical presentation of a patient with an ac-etabular labral tear is similar to the patient presentation with a meniscal tear. The patient can complain of a sharp catching pain that is often associated with a popping and a sensation of locking or giving way of the joint.15,18,19 Patients can have pain in the anterior groin, anterior thigh, buttock, greater trochanter, and medial knee. The reason for the variety in location of complaints of pain is that the sensory supply to the hip joint is 65% from the obturator nerve, so pain in this area is referred to the groin and the medial aspect of the knee. Approximately 30% of the sensory dis-
FIGURE 17.2. An abductor lurch may occur as a compensatory mechanism to reduce the forces across the joint. By shifting the torso over the involved hip, the center of gravity is moved closer to the axis of the hip, shortening the lever arm moment and reducing compressive joint forces.
Lunate articular surface Labrum
Lunate articular surface Labrum
FIGURE 17.3. The ball-and-socket configuration of the hip allows multiplanar motion.
tribution is from the femoral nerve, which refers to the anterior portion of the thigh. The remaining sensory distribution is from a branch of the sciatic nerve; therefore, the pain is referred to the buttock20 (Figure 17.6). In a retrospective study, McCarthy and associates reviewed 94 consecutive patients with intractable hip pain who underwent hip arthroscopy. They found statistically significant associations between the pre-operative clinical presentation and arthroscopic operative findings. Acetabular labral tears detected arthro-scopically correlated significantly with symptoms of anterior inquinal pain (r = 1), painful clicking episodes (r = 0.809), transient locking (r = 0.307), and giving way (r = 0.320). Byrd found the most common injury mechanism was hip hyperextension combined with external rotation causing an anterior acetabular labral tear. Axial loading of the hip in a flexed position was the most common mechanism for a posterior acetabular labral tear.7
Secondary problems can occur, such as joint mobility limitations analogous to adhesive capsulitis of the shoulder. Over time, limited joint motion and postural alterations can transfer into faulty mechanics and compensatory stress of joints above or below the hip. Additional musculoskeletal pain syndromes and functional limitation can develop. Secondary knee irritation or lumbopelvic problems are common and
may need to be addressed in the rehabilitation of the total kinetic chain and integrated functional unit.
Because of the mobile ball-and-socket configuration of the hip joint, few functional movements are uniplanar. However, for examination purposes, the six principal directions of movement are flexion, extension, abduction, adduction, internal rotation, and external rotation (Figure 17.7). The typical capsular pattern of restriction is characterized by a gross limitation of flexion, abduction, and internal rotation with minimal loss of extension and external rotation.21-23 The capsular pattern indicates the capsule of the joint is affected. This is a common finding following an ar-throscopic procedure. The joint is distended with saline during the procedure, and any bleeding that occurs from arthroscopic debridement within the joint can cause inflammation of the synovial lining of the joint.
Normal parameters of range of motion can vary greatly. Goniometric measurements of passive range of motion (PROM) are taken bilaterally of the patient's hip and knee joints. Typically, in the prone position, the hip can be extended 30 degrees (Figure 17.8). In the supine position, hip flexion requires that the contralateral extremity be flat on the table to eliminate accessory or compensatory movement that can occur due to pelvic tilt.
Recording abduction and adduction requires that the pelvis again be stabilized to eliminate accessory movement that may falsely indicate greater range of motion. Abduction averages 45 to 50 degrees and adduction 20 to 30 degrees (Figure 17.9). With the hip flexed 90 degrees, internal rotation averages 35 degrees and external rotation averages 45 degrees (Figure 17.10).24
A succinct abbreviated examination can be used to quickly determine if there is any gross restriction in range of motion of the hip:
• To test for abduction, have the patient stand and spread his or her legs as far apart as possible. One should be able to abduct approximately 45 degrees from the midline (Figure 17.11).
• For adduction, instruct the patient to alternately cross his or her legs while standing. One should be able to achieve approximately 20 degrees of adduction (Figure 17.12).
• For flexion, have the patient draw each knee to the chest as far as possible without bending the back (Figure 17.13).
• For combined flexion and adduction, have the patient sit in a chair and alternately cross one thigh over the other (Figure 17.14).
• For extension, have the patient sit in a chair with the arms folded across the chest and then rise to a standing position (Figure 17.15).
The Thomas test can alternately be used to quan-titate hip flexion or the presence of a hip flexion contracture (Figures 17.16, 17.17). For measuring flexion, the knee is brought toward the chest. The contralateral hip is maintained in extension and the degree of flexion of the hip being examined is recorded. Conversely, for assessing a flexion contracture, the knee of the contralateral extremity is brought maximally to the chest. The hip being examined is then brought toward extension. Inability to lay the leg flat on the table reflects a hip flexion contracture. Inordinate tightness of the iliotibial band can most easily be detected using the Ober test. The patient is positioned on his or her side with the suspect hip placed up. With the hip extended and knee flexed, limitation of passive adduction is indicative of a tight iliotibial band (Figure 17.18).
Strength of the hip muscles is assessed using manual muscle tests as described by Hislop and Mont-gomery.25 Intrarater reliability of manual muscle testing grades has been found to be reliable by several authors.26,27
Common physical findings include (1) pain elicited by internal rotation of the hip joint flexed at 90 de-grees19; (2) pain elicited by axial compression of the hip joint flexed at 90 degrees; (3) pain and/or a popping sensation with a Thomas test15,28; and (4) a positive hip extension test. This test is performed with the patient in a prone position.15,29 The patient's affected lower extremity is passively taken into combined extension and external rotation. A positive test result is replication of the patient's pain and/or a popping sensation.21 In a retrospective study comparing
preoperative clinical findings with arthroscopic findings, McCarthy et al. found that a positive hip extension test was correlated with an arthroscopic finding of an acetabular labral tear (r = 0.676).20
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This ebook provides an introductory explanation of the workings of the human body, with an effort to draw connections between the body systems and explain their interdependencies. A framework for the book is homeostasis and how the body maintains balance within each system. This is intended as a first introduction to physiology for a college-level course.