Introduction

The hip is a complex joint that is surrounded by deep muscle and ligamentous tissues. Problems of the hip are often not recognized as the source of symptoms in a timely fashion. The time delay until treatment leaves patients in search of answers, which confounds and confuses the clinical picture after other treatments have been rendered. The modern understanding of other joints (e.g., knee, shoulder) developed rapidly as arthroscopic and clinical evaluations became structured, and the physical examinations became more inclusive as this understanding grew. At this time, the hip is being replaced, resurfaced, reconstructed, and reshaped as never before to provide improved patient function and to meet the expectations of both the patient and the surgeon.

The physical examination of the adult and adolescent hip continues to evolve as a product of biomechanical and surgical advancements, and it is a comprehensive assessment of three distinct tissue types that interrelate in a static and dynamic fashion. A thorough physical assessment is critical to the development of treatment options, interoperative considerations, and future diagnostic strategies. Hip motion occurs in 6 degrees of freedom in a symphony of musculotendinous, ligamentous, and osseous balance. To appreciate this achievement of function, it is important to understand the balance and interrelationship that each system has with the others. The hip will optimally be recognized early during the presentation of the complaint, but this is dependent on a consistent way of interpreting these interrelationships. The goal of this chapter is to do three things: 1) to identify key tests to be routinely performed during the physical examination of the hip; 2) to describe how these critical tests are performed, and to begin a discussion of the biomechanical importance of these assessments.

Ideally, orthopedic surgeons are familiar with an organized basic hip examination that can be performed quickly and efficiently to screen the hip, back, abdominal, neurovascular, and neurologic systems and to find the comorbidities that coexist with complex hip pathology. It is important that the physical examination of the hip is inclusive enough to rule out other joints as the primary cause of a complaint. Each examination or physical evaluation has a specific way of being performed, although interobserver consistency and practice are some of the most important aspects of the evaluation.

The order of the examination is one that is easy on the patient and on the flow of the physician and an assistant, if available. A physical examination is dictated by the pertinent history and especially by the age of the patient; any history of trauma or other related symptoms of the back; or neurologic, abdomen, or lower-extremity complaints. Some hint of the presence of an intra-articular cause versus an extra-articular one is assimilated by the presenting location. A review of the patient’s history is obtained, which includes the history of the present condition, the date of the onset, the presence or absence of trauma, the mechanism of injury, the pain, the location, and factors that increase or decrease any associated pain. The presence or absence of popping is also beneficial to assess. Potential sources of disruption of the vascular supply of the femoral head are assessed, including metabolic disorders such as abnormalities that involve lipids, the thyroid, homocysteine, and clotting mechanisms. The patient’s social history can also affect the blood supply to the femoral head; therefore, the presence of or exposure to tobacco, alcohol, steroids, and altitude issues are routinely recognized.

Past tests or evaluative studies are recorded, which may include magnetic resonance imaging or arthrography, x-rays, laboratory results, or previous consults. Current limitations that involve the activities of rotation (e.g., getting into or out of a bathtub or car, activities of daily living, jogging, walking, stairs) will help to detect and direct possible further intra- or extra-articular assessment. The presence of associated complaints (e.g., abdominal or back pain, numbness, weakness, cough or sneeze exacerbation) helps to rule out thoracolumbar issues, which are occasionally confused with the hip as a partial or dominant cause of complaint. Finally, the goals of treatment are discussed and reviewed with the patient.

A Modified Harris Hip Score is a general guide to establishing gross levels of function. Other hip scores have been outlined with quantifications in more specific patient populations, such as the Non-Arthritic Hip Score, the Hip Disability and Osteoarthritis Outcome Score, the Musculoskeletal Function Assessment, the Short Form 36, and the Western Ontario and McMaster University Osteoarthritis Index. An ongoing consensus score is under way by the Multicenter Arthroscopy of the Hip Outcomes Research Network (MAHORN) Group to add an internationally accepted score; this is in its final stages of testing. This test will help to compare outcomes and provide a consensus for comparison among examiners as well as among different centers. The use of a verbal analog score is also subjectively useful.

The technique of physical examination

Hip complaints may present in a complex fashion that requires a thorough assessment to separate the comorbidities that frequently exist. The technique of physical examination is dependent on the examiner’s experience and efficiency. Adequate time with the patient is scheduled to allow for a comprehensive assessment. Most hip examiners have a structured examination that is generally used in all cases and that helps to differentiate the specific pathologies upon presentation. The physical examination will be fine tuned and directed through the review of the history of present illness.

As with other extremity examinations, loose-fitting clothing around the waist that allows for access and patient comfort is helpful. An assistant to record the examination is useful for the accuracy and documentation of the examination. A standardized written form is helpful for thoroughness, especially when first starting a comprehensive hip evaluation or when the presentation is complex.

A vast number of tests exist for the examination of the hip, and it is not necessary to include them all in a single evaluation. Therefore, components of the examination can be classified as basic, which should always be included, and specific, which should be used as needed to define a specific diagnosis or combination of diagnoses. The most common examinations as determined by the MAHORN Group are shown in Table 6-1. This is a consensus among hip specialists to identify basic and specific components of the physical examination.

Table 6–1 Most Frequent Tests Performed by Mahorn Group Specialists

The standing examination of the hip

As the patient stands, a general point of pain is noted with one finger, and this can usually help to direct the examination. Pain in the groin region leads to the suspicion of an intra-articular problem, and lateral-based pain is primarily associated with both intra- and extra-articular aspects. Posterosuperior pain requires a thorough evaluation for differentiating hip and back pain; back issues are many times noted concomitantly with musculotendinous hip pathology. The shoulder height and iliac crest heights are noted to evaluate leg-length discrepancies. The 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 spinal motion is recorded.

Gait abnormalities often help to detect hip pathology as a result of the hip’s role in supporting the body weight. Joint stability, preservation of the labrum and articular cartilage, and proper functioning of the hip joint involve three biomechanical and anatomic geometries of the femur and the acetabulum: femoral head–neck offset, acetabular anteversion, and acetabular coverage of the femoral head. These relationships are important for the transfer of dynamic and static load to the ligamentous and osseous structures. Hip congruency (i.e., the rotation of the femoral head within the acetabular–labral complex) and articular stabilization (i.e., limiting translations of the femoral head within the acetabular–labral complex) are also regulated by the ligaments and muscles that cross the hip joint. The ligamentous capsule must maintain the stability of the hip, whereas the musculature of the lower limbs produces the forces that are required during ambulation.

The patient is taken into the hallway so that a full gait of six to eight stride lengths can be observed (video). Key points of gait evaluation include foot rotation (i.e., the internal/external progression angle), pelvic rotation in the X and Y axes, stance phase, and stride length. The gait viewed from the foot-progression angle will detect the possibility of osseous or static rotatory malalignment that exists with increased or decreased femoral anteversion as compared with a capsular or musculotendinous issue. The knee and thigh are observed simultaneously to assess for any rotatory parameters. The knee may want to be held in either the internal or external rotation to allow for proper patellofemoral joint alignment, but this may produce a secondary abnormal hip rotation. This abnormal motion is usually present in cases of severe increased femoral anteversion that precipitates a battle between the hip and knee for a comfortable position, which will affect the gait.

Pelvic rotation is assessed by noting iliac crest rotation and terminal hip extension. On average, a normal gait requires 8 degrees of hip rotation and 7 degrees of pelvic rotation, for a total rotation of 15 degrees. 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 is associated with laxity or hip-flexion contractures, especially when seen in combination with increased lumbar lordosis or a forward-stooping posture. 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.

The normal gait can be broken down into two phases: the stance phase (60%) and the swing phase (40%). During the stance phase, the body weight must be supported by a single leg with the gluteus maximus, vasti, gluteus medius, and gluteus minimus providing the majority of the support forces. The maximum ground reactive force occurs during 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 is an unbalanced stance phase that is attributed to abductor weakness and that is often referred to as an abductor lurch. The Abductor Deficient gait may present in two ways: with a shift of the pelvis away from the body (i.e., a “dropping out” of the hip on the affected side) or with a shift of the weight over the adducted leg (i.e., 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, thus limiting the duration of weight bearing (i.e., a self-protecting limp caused by pain). A short leg gait is noted by the 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 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 reference for the patient’s function. As the patient lifts and holds one foot off the ground for 6 to 8 seconds, the contralateral hip abductor musculature and neural loop of proprioception are being tested. The pelvis will tilt toward 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 pattern; therefore, the rationale is that a shift of more than 2 cm constitutes a positive Single Leg Stance Phase test. Table 6-2 provides an outline of the standing examination.

Table 6–2 Standing Examination Associations

The seated examination of the hip

The seated hip examination consists of a thorough neurologic and vascular examination (video). The need to check the fundamentals would appear obvious even in healthy individuals. Criteria exist for both the care of the patient and coding. The posterior tibial pulse is checked first, any swelling of the extremity is noted, and an inspection of the skin is performed at this time. A straight-leg raise test is then performed by having the patient extend the knee into full extension. This test is helpful for detecting radicular neurologic symptoms, such as the stretching of an entrapped nerve root.

The loss of internal rotation is one of the first signs of the possibility of an intra-articular disorder; therefore, an important assessment is the 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 is performed gently and compared between the two sides. Seated rotation range of motion is also compared and contrasted with the extended position of the hip. Table 6-3 provides normal internal and external rotation ranges of motion in these positions.

Table 6–3 Seated Examination Associations

Musculotendinous, ligamentous, and osseous control of internal and external rotation is complex (Figure 6-1); therefore, any differences in seated positions as compared with extended positions may raise the question of ligamentous abnormality as compared with osseous abnormality. Sufficient internal rotation is important for proper hip function; there should be at least 10 degrees of internal rotation during the midstance phase of the normal gait. The loss of internal rotation at the hip can be related to diagnoses such as arthritis, effusion, internal derangements, slipped capital femoral epiphysis, and muscular contracture. Pathology related to femoroacetabular impingement or to rotational constraint from increased or decreased femoroacetabular anteversion can result in significant differences between the sides. An increased internal rotation in combination with a decreased external rotation may indicate excessive femoral anteversion, although the hip capsular function will require further assessment; this is correlated with the radiographic findings. Table 6-3 provides an outline of the seated examination.

Figure 6–1 Summary of the internal rotation of cadaveric hip ligaments through ranges of motion from 30 degrees of flexion to 10 degrees of extension along a neutral swing path. After transection of the ischiofemoral ligament (Ischio), internal rotation doubled. The lateral arm of the iliofemoral ligament (Lat ilio) was also noted to contribute to the stability of the hip in internal rotation. Med ilio, medial arm iliofemoral ligament; Pubo, pubofemoral ligament.

Reprinted from Arthroscopy, 24, The function of the hip capsular ligaments: a quantitative report. Martin HD, Savage A, Braly BA, Palmer IJ, Beall DP, Kelly B. 188-95, 2008, with permission from Elsevier.