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Examination of a painful hip is fairly concise and reliable at detecting the presence of a hip joint problem. Hip joint disorders often go undetected, leading to the development of secondary disorders. Using a thoughtful approach and methodical examination techniques, most hip joint problems can be detected and a proper treatment strategy can then be implemented based on an accurate diagnosis. The purpose of this clinical commentary is to present a systematic examination process that outlines important components in each of the evaluation areas of history and physical examination (including inspection, measurements, symptom localization, muscle strength, and special tests).
Examination of a painful hip is fairly succinct. One study demonstrated that the clinical assessment can be 98% reliable at detecting the presence of a hip joint problem; although the exam may be poor at defining the exact nature of the intra-articular disorder.1 However, examination of the hip region can be quite complex due to co-existent pathology, secondary dysfunction, or coincidental findings.
For example, hip joint disease may co-exist with lumbar spine disease. Considerable attention may be necessary in order to distinguish which is the major factor. Among athletes, a significant incidence of hip pathology and concomitant athletic pubalgia can occur. The symptoms can be difficult to distinguish, especially when they co-exist.
Hip joint disorders often remain undetected for protracted periods of time. In the course of compensating for their symptoms, patients often develop secondary dysfunction. This dysfunction may lead to symptoms of trochanteric bursitis or chronic gluteal discomfort. The examination findings for the secondary disorders may be more evident and mask the underlying problem with the hip.
Coincidental findings unrelated to disorders of the hip may exist. Snapping of the iliopsoas tendon and iliotibial band are usually incidental findings without clinical significance. However, this snapping can become a source of symptoms or may exist coincidentally with hip joint pathology. Once again the clinical assessment can become challenging to distinguish the features of each.
A myriad of structures may create similar or overlapping symptoms. In addition to the joint, the clinician must be cognizant of bone problems, surrounding musculotendinous and bursal structures, neurological disorders including numerous small sensory nerves, and even visceral disorders that can refer symptoms to the hip area.
As there are various disorders that can result in a painful hip, the history may be equally varied as far as onset, duration, and severity of symptoms. For example, acute labral tears associated with an injury have gone undiagnosed for decades, presenting as a chronic disorder. Conversely, patients with a degenerative labral tear may describe the acute onset of symptoms associated with a relatively innocuous episode and gradual progression of symptoms.
In general, a history of a significant traumatic event is a good prognostic indicator of a potentially correctable problem.2 Insidious onset of symptoms is a poor prognostic indicator and suggests either underlying degenerative disease or some predisposition to injury. Patients may recount a minor precipitating episode such as a twisting injury; however, even under these circumstances, be wary that underlying susceptibility of the joint to damage may exist and, again, a less certain prognosis. With any hip joint problem, the clinician must look closely for predisposing factors. For example, femoro-acetabular impingement is a recognized cause of joint breakdown in young adults.3 Often, the cause may be multi-factorial including age, rigors of sport, and joint morphology. The management strategy may have to be multi-faceted, as well. Perhaps not all factors can be identified or corrected, but the evaluation must be thorough.
Mechanical symptoms such as locking, catching, popping, or sharp stabbing in nature are better prognostic indicators of a correctable problem.4 Simply pain in absence of mechanical symptoms is a poorer predictor. However, the presence of a “pop” or “click” is an often over-rated feature of the hip examination. This finding may indicate an unstable lesion inside the joint, but many painful intra-articular problems never demonstrate this finding, and popping and clicking can occur due to many extra-articular causes, most of which are normal.
There are characteristic features of the history that often indicate a mechanical hip problem (Table 1).5 These characteristics are helpful in localizing the hip as the source of trouble, but are not specific for the type of pathology. As expected, the pain is worse with activities, although the degree is variable. Straight plane activities such as straight ahead walking or even running are often well tolerated, while twisting maneuvers such as simply turning to change direction may produce sharp pain, especially turning towards the symptomatic side which places the hip in internal rotation. Sitting may be uncomfortable, especially if the hip is placed in excessive flexion. Rising from the seated position is especially painful and the patient may experience an accompanying catch or sharp stabbing sensation. Symptoms are worse with ascending or descending stairs or other inclines. Entering and exiting an automobile is often difficult with accompanying pain, because the hip is in a flexed position along with twisting maneuvers. Dyspareunia is often an issue due to hip joint pain, commonly a problem among females, but may be a difficulty for males as well. Difficulty with shoes, socks, or hose may simply be due to pain or may reflect restricted rotational motion and more advanced hip joint involvement.
Based on the information obtained in the history, a preliminary differential diagnosis should be formulated. The history assists the examiner in performing an appropriately directed physical examination.
The information obtained in the history is just a screening tool. The history helps direct the examination, but should not unduly prejudice the approach. The examiner must be systematic and thorough to avoid potential pitfalls and missed diagnoses. In reference to examination of the hip, Otto Aufranc6 noted that “more is missed by not looking than by not knowing.”
The most important aspect of inspection is stance and gait. The patient's posture is observed in both the standing and seated position. Any splinting or protective maneuvers used to alleviate stresses on the hip joint are noted. While standing, a slightly flexed position of the involved hip and concomitantly the ipsilateral knee is common (Figure 1). In the seated position, slouching or listing to the uninvolved side avoids extremes of flexion. (Figure 2).
An antalgic gait is often present, but dependent on the severity of symptoms. Typically, the stance phase is shortened and hip flexion appears accentuated as extension is avoided during this phase. Varying degrees of abductor lurch may be present as the patient attempts to place the center of gravity over the hip, reducing the forces on the joint. In addition, observation is made for any asymmetry, gross atrophy, spinal alignment, or pelvic obliquity that may be fixed or associated with a gross limb length discrepancy.
Certain measurements should be recorded as a routine part of the assessment. Limb lengths should be measured from the anterior superior iliac spine to the medial malleolus (Figure 3). Significant limb length discrepancies (greater than 1.5cm) may be associated with a variety of chronic conditions. Typically, if limb length difference appears to be a contributing factor, half of the recorded discrepancy should be corrected in the course of conservative treatment. Treatment with an insert is cosmetically more acceptable than a built-up shoe. Thigh circumference, while a crude measurement, may reflect chronic conditions and muscle atrophy (Figure 4). It is important to measure the involved compared with the uninvolved side. Sequential measurement on subsequent examination may be helpful as an indicator of response to therapy. Again, circumference is a crude measure that only indirectly reflects hip function, but hip disease conversely usually affects the entire lower extremity.
Range of motion of the hip should be accurately recorded in a consistent and reproducible fashion. While reduced range of motion itself is rarely an indication for arthroscopic intervention, decreased range is often a good indicator of the extent of disease and response to treatment.
The degree of flexion and the presence of a flexion contracture are determined by using the Thomas test. Maximal extension of the uninvolved hip stabilizes the pelvis, eliminating the contribution of pelvic tilt in recording flexion of the involved hip. Conversely, maximal flexion of the uninvolved hip locks the pelvis and allows assessment for a flexion contracture of the involved hip. Extension is recorded with the patient in the prone position, raising the leg.
Several effective mechanisms exist for recording rotational motion of the hip. It is important to select one and be consistent. Flexing the hip 90° and then internally and externally rotating the joint is an easy, reproducible method for recording rotational motion (Figure 5). Abduction and adduction are recorded as well.
Although this rule is not as accurate when applied to the hip than to other joints, such as the knee, it is still important to ask the patient to use one finger and point to the spot that hurts the worst. This pointing provides much useful information before beginning palpation by allowing the examiner to discern the point of maximal tenderness. Consequently, this area is reserved until last when performing the examination. This information forces the examiner to be more systematic, exploring uninvolved areas first, and enhances the patient's trust by not stimulating pain at the beginning of the examination.
Hilton's law states that “the same trunks of nerves whose branches supply the groups of muscles moving a joint furnish also a distribution of nerves to the skin over the insertion of the same muscles, and the interior of the joint receives its nerves from the same source.”7 While this quote may ensure physiological harmony among the various structures, it also explains why muscle spasms and cutaneous sensations may accompany joint irritation.
Classic mechanical hip pain is described as being anterior, typically emanating from the groin area. The hip joint receives innervation from branches of L2 to S1 of the lumbosacral plexus, predominantly L3. Consequently, hip symptoms may be referred to the L3 dermatome, explaining the presence of symptoms referred to the anterior and medial thigh, radiating distally to the level of the knee.
Intra-capsular hip pathology almost always has a component of anterior hip pain. A sensation of deep, lateral discomfort or posterior pain may be present, but usually only in conjunction with a predominant anterior component.
The classic complaint of patients with hip pathology is “groin pain.” However, the author has identified a common characteristic sign of patients presenting with hip disorders. The patient will cup their hand above the greater trochanter when describing deep interior hip pain. The hand forms a C and thus this has been termed the “C-sign” (Figure 6).5 Because of the position of the hand, this sign can be misinterpreted as indicating lateral pathology such as the iliotibial band or trochanteric bursitis, but quite characteristically, the patient is describing deep interior hip pain.
Palpation is usually unrevealing as far as any specific areas of discomfort related to an intra-articular source of hip symptoms. Obviously, one must be familiar with the topographical and deep anatomy in order to correlate the structures being palpated. Aufranc6 noted that “a continuing study of anatomy marks the difference between good and expert ability.”
Palpation is used more to assess potential sources of hip-type pain, other that the joint itself. It is important to be systematic, palpating the lumbar spine, sacroiliac (SI) joints, ischium, iliac crest, lateral aspect of the greater trochanter and trochanteric bursa, muscle bellies, and even the pubic symphysis, each of which may elicit information regarding a potential source of hip symptoms.
Manual muscle testing is a crude measure of hip function but may elicit useful information. If injury to a specific muscle group is suspected, resisted contraction should reproduce localized symptoms.
Active range of motion and resisted active range of motion may also reproduce joint symptoms. However, when carefully interpreted, a distinction can be made between symptoms of a muscle strain and hip pain. This differentiation may be least clear with a strain of the hip flexors. In this situation, active hip flexion reproduces pain while passive flexion should not.
Special tests include those maneuvers used to define other sources of symptoms as well as those used to define symptoms localized to the hip. The examiner should also be aware of how tests for other sources might affect a painful hip.
The passive straight leg raise is important for assessing signs related to lumbar nerve root irritation (Figure 7). The test may also provoke local joint symptoms. The Patrick or Faber test (flexion, abduction, external rotation) has been described both for stressing the SI joint, looking for symptoms localized to this area, and for isolating symptoms to the hip (Figure 8). Differentiation between pain localized to the SI joint and the hip is usually easy. The single most specific test for hip pain is log rolling of the hip back and forth (Figure 9). Log rolling moves only the femoral head in relation to the acetabulum and the surrounding capsule. No significant excursion or stress occurs on myotendinous structures or nerves. Absence of a positive log roll test does not preclude the hip as a source of symptoms, but its presence greatly raises the suspicion.
Forced flexion combined with internal rotation is a more sensitive maneuver which may elicit symptoms associated with even subtle hip pathology (Figure 10). This test is often referred to as an “impingement test” eliciting symptoms associated with femoro-acetabular impingement. However, this maneuver is usually uncomfortable with any irritable hip and is not specific for the nature of the pathology. An accompanying pop or click may be present, but it is more important to determine if this maneuver reproduces the type of hip pain that the patient experiences with activities. This maneuver may normally be uncomfortable, so it is important to compare the response on the symptomatic and asymptomatic sides. Alternatively, forced abduction with external rotation will sometimes produce symptoms (Figure 11).
An active straight leg raise or straight leg raise against resistance often elicits hip symptoms (Figure 12). This maneuver generates a force of several times the body weight across the articular surfaces and actually can generate more force than walking.
The Trendelenburg test is used to assess for gross abductor weakness. This weakness may develop as a chronic condition secondary to joint disease or may represent a neuromuscular disorder. The patient stands on the affected leg and lifts the contralateral leg off of the ground. With adequate abductor strength the pelvis should remain level. With gross abductor weakness the pelvis drops towards the contralateral side (Figure 13).
Various maneuvers may create a click or popping sensation. This popping may reflect an unstable labral tear or chondral fragment. However, the origin of these clicks or pops is often unclear and do not uniformly reflect an intraarticular lesion.
Snapping of the iliopsoas tendon is a common incidental finding without clinical significance. However, the snapping can become painful and can be difficult to distinguish from an intra-articular problem. The snapping is sometimes subtle, better experienced by the patient than detected by the examiner; but is often quite prominent with a distinct audible component. The characteristic examination maneuver for creating the snap is bringing the hip from a flexed, abducted, externally rotated position into extension with internal rotation (Figure 14).8 The snapping occurs as the iliopsoas tendon transiently lodges on the anterior aspect of the hip capsule or pectineal eminence. Often this snapping is a dynamic process better demonstrated by the patient than can be elicited by the examiner. The maneuver performed by the patient can be variable in sitting, standing, or lying down; but the snapping invariably occurs when going from flexion to extension. It is important not to misinterpret snapping of the iliopsoas tendon as an intra-articular problem, but it is also likely that numerous intra-articular disorders get misdiagnosed as a “snapping hip syndrome.” For recalcitrant symptomatic snapping of the iliopsoas tendon, fluoroscopy with iliopsoas bursography and ultra-sonography can often substantiate the source. However, these studies may not be conclusive, therefore, the history and examination findings remain the most reliable clinical assessment tool.
Snapping due to the iliotibial band is more easily distinguished from a hip joint disorder because of its lateral location.9 These patients frequently present with a sensation that their hip is subluxing or dislocating. The process is dynamic in that the patient can demonstrate much more vividly than can be detected by the examiner. The visual appearance is created by the tensor fascia lata flipping back and forth across the greater trochanter, and not instability of the hip. With the patient in the lateral position, the snapping may be created by flexing and extending the hip, moving the abductor mechanism across the greater trochanter (Figure 15). Ober testing to assess for tightness of the abductor mechanism can be performed by lowering the leg on the table.
Good generalizations exist regarding snapping hip syndromes. If you can hear it from across the room it is the iliopsoas tendon, and if you can see it from across the room it is the iliotibial band.
Athletic pubalgia occurs most often in male athletes.10 The symptoms emanate from the groin and the findings can be confused with a hip joint problem. This condition often co-exists with hip joint pathology in an athletic population. Diminished rotational motion of the hip is compensated by increased pelvic motion. This motion places more stress on the pelvic stabilizers and can result in soft tissue breakdown of the lower abdominal muscles, pelvic floor, and adductor origins. This condition is characterized by localized soft tissue tenderness to palpation on examination (Figure 16); and absence of discomfort with passive range of motion that would be observed in patients with hip joint pathology. Resisted sit ups, hip adduction, and sometimes hip flexion may also precipitate symptoms associated with this soft tissue disorder.
Historically, hip joint problems in athletes have been largely neglected. This neglect has been due to a combination of factors including poor assessment skills and, without interventional methods to address these problems, little incentive has existed to pursue an investigation. Arthroscopy has defined the existence of numerous intra-articular disorders that previously went undetected and untreated. This information has served to enhance clinical assessment skills and has stimulated advancements in investigative studies.1 Using a thoughtful approach and methodical examination techniques, most hip joint problems can be detected. A proper treatment strategy can then be implemented including the role of conservative measures and interventional methods based on an accurate diagnosis.