Jason R. Hull
The primary goals of any patient encounter are formulation of the correct diagnosis and initiation of an appropriate course of treatment. Despite many advances in laboratory and imaging technology, a thorough history and physical examination remains the most effective instruments in achieving these goals. The clinician may establish a provisional diagnosis early in the patient encounter after hearing only the patient's presenting complaint and history of present illness. A detailed history will direct the focus and extent of the physical examination and aid in refining the diagnosis. Close interaction with the patient during the history and physical examination promotes accurate assessment of the patient's level of disability and formulation of an individualized treatment plan appropriate for their expectations and goals for recovery.
History
Details of the patient's presenting symptoms should be explored in a clear, systematic fashion and include discussion of location, timing, quality, severity, and aggravating/relieving factors. Pain is the most common complaint that drives orthopaedic patients to seek medical evaluation. Asking the patient to point to the most painful area of the knee is a simple way to determine the anatomic location of the symptoms. The timing of onset should be explored, because symptoms may start insidiously and slowly progress with a waxing and waning course, or may start suddenly after a major or minor traumatic event. The pattern of symptoms may provide immediate insight regarding a presumptive diagnosis. For example, initially osteoarthritis may cause aching pain that localizes to one area of the knee, occurs only after prolonged weight-bearing activities, and is relieved by short periods of rest. This may be differentiated from early pain owing to inflammatory arthritis, which may be more diffuse, constant, and unrelieved by rest. Besides pain, the presence of mechanical symptoms and subjective instability should be reviewed. Locking, catching, and popping are suggestive of a meniscal tear, loose body, or focal lesion of the articular surface. Instability can be caused by true ligamentous insufficiency or may be owing to reflex inhibition of the quadriceps from knee pain or effusion. It is important to inquire about past events specific to the joint, as patients may not readily recall childhood illnesses or conditions that affected the knee, and they may not mention previous minor surgical interventions such as arthroscopy.
Ascertaining the patient's level of dysfunction is paramount. Informed discussions regarding risk-benefit ratios of potential conservative and surgical treatment options cannot take place until this is established. Functional deficits should be evaluated in the context of the patient's baseline level of physical activity including activities of daily living, occupational and work-related activities, and leisure activities (Table 16-1). As symptoms worsen patients typically exhibit progressive activity modification and adaptive mechanisms, such as using assistive devices for ambulation (cane, walker), using the hands to assist in rising from a chair, and altering stair climbing technique or avoiding stairs altogether. Standardized physician-administered (e.g., Knee Society Clinical Rating System) and patient-administered (e.g., Western Ontario and McMaster University Osteoarthritis Index) rating scales can be useful in evaluating patients' functional deficits. Perceptions regarding level of disability may vary greatly between patients with different occupations or cultural backgrounds. Because of the physical demands of his work, a laborer may perceive himself to be disabled earlier in the disease process than a sedentary office worker. Some patients tolerate lifestyle changes more effectively than others and may be willing to change careers or give up favorite leisure activities to avoid surgical treatment.
All previous medical and therapeutic interventions, both prescribed and unprescribed, should be discussed. Patients will often fail to mention treatments such as over-the-counter nonsteroidal anti-inflammatory medications and self-directed therapeutic exercise. Discovering the
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frequency, duration, and efficacy of all prescribed interventions, including activity modification, orthotics, physical therapy, pain and anti-inflammatory medications, and injections, is important for determining the next step in treatment.
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TABLE 16-1 History: Assessing Functional Deficits and Disability |
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A review of systems is essential for a complete history and may be included in the history of present illness. Specific inquiry regarding constitutional symptoms may uncover fever, anorexia, weight loss, fatigue, and generalized morning stiffness, which are indicative of an inflammatory condition such as rheumatoid arthritis or infection. The review of systems should also cover other possible sources of knee symptoms, including the neurovascular system, spine, and adjacent joints. The hip and spine are common sources of referred pain to the knee (Fig. 16-1). The review of systems should also be used to identify medical issues that require attention prior to any surgery, such as undiagnosed cardiac or respiratory disease and recent or ongoing infections, particularly of the genitourinary tract and oropharynx.
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Figure 16-1 Radiographs of a 54-year-old patient referred for treatment of severe bilateral knee pain. A: Standing anteroposterior radiograph of both knees demonstrates mild to moderate osteoarthritis. Note the oblique view of both knees, as the patient could not internally rotate her hips to neutral for the study. B: Anteroposterior radiograph of the pelvis demonstrates severe arthrosis of both hip joints. Staged bilateral total hip arthroplasty resulted in complete resolution of her symptoms. |
The patient's past medical, past surgical, family, and social histories will offer diagnostic clues as well as information that dictates available treatment options and the manner in which they are executed. The medical history may reveal an underlying systemic inflammatory condition as the cause for the knee condition and preclude nonarthroplasty surgical options. An extensive medical history, especially cardiac, may eliminate surgical options altogether. A review of the patient's medications may identify active medical conditions the patient failed to discuss previously. In addition, make note of any medications that should be discontinued perioperatively, such as nonsteroidal anti-inflammatory agents, anticoagulants, and disease-modifying antirheumatic drugs. The social history should include details of the patient's current living conditions and whether the patient will have adequate assistance at home after hospital discharge. The patient's use of alcohol, tobacco, or illicit substances must be documented accurately, as these agents may necessitate alterations in perioperative medical management or possibly disqualify the patient from surgical intervention.
Physical Examination
As with collection of a complete history, the physical evaluation of the patient presenting with knee symptoms must be completed in a systematic fashion. The order and organization of the exam is a matter of personal preference, but in general must include inspection, palpation, range of
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motion, ligamentous exam, and neurologic and vascular evaluation. The examination should include evaluation of both knees. Normal findings are most frequently symmetrical, so asymmetry may indicate the presence of pathology. To minimize guarding during examination of the affected knee, examine the uninvolved knee first. Avoid areas of known tenderness and exacerbating maneuvers until as late in the exam as possible.
Inspection, Palpation, and Range of Motion
The physical examination may begin the first time the clinician lays eyes on the patient. Briefly observing how the patient moves on the way to the examination room may provide a more candid glimpse of the patient's gait and reliance on assistive devices than when he or she is asked to ambulate during the formal exam. Much can be learned regarding a patient's level of physical dysfunction and disability by general observation during the interview as well as during the formal examination. General appearance and body habitus must be noted. Observe the patient's posture of the spine, hips, and knees while seated. While removing shoes and socks and getting on and off the exam table, the patient may exhibit abnormal movement to compensate for pain or stiffness. Watch carefully for facial expressions and wincing that indicate pain.
The formal examination may begin with the patient standing. Inspection of the spine may reveal a scoliosis or alteration of normal lumbar lordosis with associated paravertebral spasm. Check the range of motion of the lumbar spine with flexion, extension, side bending, and rotation. Patients with osteoarthritis of the lumbar spine often experience lumbar pain with extension. The bony landmarks of the pelvis can be palpated to assess for pelvic obliquity. A fixed pelvic obliquity owing to lumbosacral disease will not correct when a block is placed under the apparently short limb. Abductor weakness, often associated with hip pathology, can be recognized with the Trendelenburg test. During a single leg stance, the abductor muscles on the supporting extremity contract to maintain a level pelvis. A positive test occurs when the abductors are not strong enough to support the body's weight and the hemipelvis opposite the supported limb drops toward the floor.
Gross limb alignment in the standing position provides some indication of the location of the knee pathology. Genu varum suggests involvement of the medial compartment, whereas genu valgum suggests involvement of the lateral compartment. During gait these deformities may prove to be dynamic, with worsening of the varus and valgus deformities during stance phase observed as lateral and medial thrusts at the knee, respectively. The presence of a thrust in the setting of osteoarthritis has prognostic implications, as these knees demonstrate a propensity for disease progression. A dynamic recurvatum deformity during stance phase should alert the clinician to the possibility of an underlying neurologic condition, extensor mechanism dysfunction, or significant ligamentous laxity. Posture of the ankles and feet should not be overlooked. Hindfoot bracing for a flexible planovalgus deformity of the foot and ankle may provide symptomatic relief for an ipsilateral valgus knee.
Assessment of the patient's gait pattern is an essential component of the examination. The patient's effort to reduce joint load at the knee can result in many compensatory gait changes. Pain during weight bearing causes the patient to limit the amount of time spent in stance phase of gait, producing an antalgic gait (classic limp), which is the most common adaptive gait pattern. Decreased cadence may be observed, which effectively reduces all external moments on the affected knee. Reduced stride length results from a decrease in forward reach of the involved extremity in late swing phase, which diminishes the external sagittal plane moment at the knee during heel strike. An out-toeing gait may be observed in patients with painful varus osteoarthritis of the knee, which reduces the adduction moment at the knee by shortening the moment arm. Likewise, patients may lean the trunk toward the affected weight-bearing extremity to reduce the moment arm between their center of gravity and the limb's mechanical axis. This should not be confused with the Trendelenburg lurch observed with hip pathology and concurrent abductor weakness and dysfunction.
The remaining components of an abbreviated hip and spine exam can be completed with the patient lying supine before focusing on the knee. Patients with a lumbar radiculopathy may exhibit tenderness in the region of the sciatic notch. The clinician should perform maneuvers that place the sciatic nerve under tension, including the straight leg raise and contralateral straight leg raise tests. Examine the hips, starting with palpation of the greater trochanter. Localized tenderness suggests greater trochanteric bursitis, which can present with referred pain to the lateral thigh and occasionally the lateral aspect of the knee. The ability to perform an active straight leg raise against gravity and added resistance should be tested. Groin and anterior hip or thigh pain with this maneuver may suggest intra-articular hip pathology. Active side-lying hip abduction may produce similar symptoms, and patients with advanced hip disease may not be able to overcome gravity. Passive hip motion may also produce groin and thigh pain. Loss of hip motion, especially flexion and internal rotation, is a strong indicator for the presence of advanced hip pathology.
As the examination moves toward the knee, global inspection of the lower extremities should be performed. Muscle tone, atrophy, and defects in the thigh and calf should be noted. Recording thigh and calf circumference at fixed distances above and below the patella allows objective measurement of muscle atrophy. The presence and severity of peripheral edema should be noted, along with any pretibial skin changes or varices associated with chronic venous stasis.
The overall alignment of the extremity should be reassessed. In thin patients, varus and valgus alignment can be quantified with a goniometer centered on the anterior aspect of the patella. Deformities of the thigh and lower leg should not be overlooked. Many patients will fail to mention remote trauma and surgery in their history. Healed scars should be discussed with the patient, because they may indicate the presence of posttraumatic or surgical deformities that are not outwardly visible, especially in overweight and obese patients. Scars about the knee may provide insight regarding the underlying diagnosis and should be accurately documented for preoperative planning. Skin rashes
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may suggest a systemic cause for the patient's knee pathology. When present over the knee, rashes are associated with increased risk of surgical site infection and should be treated prior to operative intervention.
Diffuse and localized soft tissue swelling should be assessed with the patient supine and the knee in extension and in flexion. Knee effusions can be assessed by compressing the suprapatellar pouch and assessing ballottement of the patella. Effusions must be differentiated from synovial thickening or bogginess, which suggests inflammatory arthritis. Although nonspecific, slight skin warmth over the knee relative to the adjacent calf and thigh can indicate the presence of a generalized synovitis. Localized swelling may represent the site of isolated pathology or may be an indicator of a more remote or generalized process. For example, localized medial joint line swelling may be identified in the presence of a meniscal cyst with an underlying meniscal tear. In contrast, swelling and fullness in the popliteal fossa at or medial to the midline commonly represents a popliteal (Baker) cyst. A popliteal cyst can be associated with any process that produces a chronic effusion, such as a remote, isolated process that results in synovitis, or a generalized condition such as inflammatory arthritis.
A thorough understanding of the topical and underlying gross anatomy of the knee joint is imperative for diagnosing underlying knee pathology. The normal anatomic landmarks of the anterior knee may be obscured by a large knee effusion or diffuse soft tissue swelling. Bony landmarks should be identified and palpated, including the femoral epicondyles, fibular head, tibial tubercle, patellar margins, and medial and lateral joint lines. Bony thickening at the joint line suggests the presence of osteophytes. Note areas of localized tenderness. Soft tissue structures adjacent to or crossing the knee joint, such as the pes anserine bursa and hamstring tendons, are often significant pain generators and should not be ignored. The integrity of the extensor mechanism can be checked with an isometric quadriceps contraction and straight leg raise.
Knee range of motion can be assessed in the supine position. By convention, full extension is 0 degrees, with up to 10 degrees of hyperextension considered normal. Flexion in the normal adult knee is to approximately 135 or 140 degrees, with 105 degrees required for normal performance of activities of daily living in Western societies. Comparison of active and passive range of motion is necessary to distinguish between joint contracture and extensor lag. A flexion contracture is identified by the inability to passively position the knee in full extension. Causes include soft tissue contracture such as hamstring and gastrocnemius tightness, and mechanical block from a meniscus tear, loose body, or osteophyte formation. A discrepancy in active and passive extension represents an extensor lag and may be attributable to pain or extensor mechanism dysfunction from weakness or disruption. A knee with a large joint effusion assumes a 15- to 25-degree resting position and can cause loss of both active and passive flexion and extension. During range of motion assessment, crepitus is a common finding and may be localized to a particular compartment by palpation of the knee.
Evaluation of the patellofemoral joint should begin with the patient standing. The Q-angle (quadriceps angle), which is the acute angle formed by intersecting lines drawn from the center of the tibial tubercle to the center of the patella and from the center of the patella to the anterior-superior iliac spine, is a measure of the lateral pull of the quadriceps on the patella. A Q-angle >15 to 17 degrees is associated with altered patellofemoral mechanics and anterior knee pain. Complex torsional deformities of the lower extremity, most commonly increased femoral anteversion, can be associated with an increased Q-angle and should be evaluated during assessment of hip motion. Tracking of the patella in the femoral sulcus should be observed during gait and with both active and passive knee extension. Excessive lateral movement of the patella as it exits the femoral sulcus during terminal knee extension is known as the J-sign. Typically the patella does not articulate with the femoral sulcus until the knee is flexed 25 to 30 degrees, so patellar tilt and medial-lateral patellar glide should be assessed with the knee in a slightly flexed position. Lack of patellar mobility, as well as lateral tracking with crepitus as the knee flexes past 30 degrees, may indicate the presence of patellofemoral arthritis. Patella alta and baja can be assessed clinically with the knee flexed 90 degrees over the end of the exam table. Tenderness of the medial and lateral facets of the patella can be evaluated, but may be falsely positive in the presence of interposed synovitis.
Evaluation of the menisci should begin with palpation of the medial and lateral joint lines. Tenderness at the apex of a meniscal tear is a common finding owing to its peripheral nerve fibers and localized synovitis. Numerous provocative tests exist for evaluation of the menisci, most of which attempt to reproduce pain or palpable clicks by trapping the abnormally mobile or torn meniscus between two joint surfaces. Of these, the McMurray test is probably the most widely used. With the patient supine, the knee is brought into deep flexion and maximal external rotation with one hand on the foot. The opposite hand is placed on the knee with the fingers over the posteromedial joint line, and the knee is brought into extension while a varus force is applied to the knee. Posteromedial pain and a palpable or audible click indicate a positive test. The maneuver can be repeated for the posterolateral meniscus by internally rotating the tibia and applying a valgus force as the knee is passively extended.
Ligamentous Evaluation
Determination of knee joint stability is important for establishing a diagnosis and formulating potential conservative and operative treatment plans. The clinician must be able to distinguish isolated ligament deficiency from complex and rotational instability patterns. However, exhaustive review of the many specific tests for ligament integrity and complex instability patterns of the knee are beyond the scope of this chapter. Simple evaluation of the cruciate and collateral ligaments is presented here. The reader should refer to a comprehensive source for a complete review of the ligamentous examination of the knee.
The anterior cruciate ligament is the primary restraint to anterior movement of the tibia on the femur. Its integrity is best evaluated with the Lachman and anterior drawer tests.
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The Lachman test is performed with the knee in 30 degrees of flexion. With one hand stabilizing the femur, anteriorly directed pull is applied to the tibia. A positive test results in excessive anterior translation of the tibia with a soft end point. In knees that are difficult to examine, such as those of obese patients, or in the setting of acute pain or swelling, the anterior drawer test may be useful. With the hip flexed 45 degrees and the knee flexed 90 degrees, the foot is stabilized on the exam table and again anteriorly directed pull is applied to the tibia. The posterior cruciate ligament is the primary restraint to posterior movement of the tibia on the femur. It is best evaluated with the posterior drawer test, performed with the extremity in the same position used for the anterior drawer test. A positive test is marked by posterior subluxation of the tibia on the femur when a posteriorly directed force is applied to the anterior tibia.
Evaluation of the collateral ligaments is performed by applying simple varus and valgus stresses to the knee in both full extension and again with the knee flexed 30 degrees. In full extension, the collateral ligaments, posterolateral capsule, and posteromedial capsule are all in a taut position. Therefore, varus and valgus stresses applied with the knee in full extension tests the integrity of the collateral ligaments as well as the posterolateral and posteromedial capsular structures. The posterior capsular structures relax when the knee is flexed 30 degrees, better isolating the collateral ligaments in resisting varus and valgus stresses. The cruciate ligaments are also taut in extension, so the presence of significant laxity to varus or valgus stress in full extension suggests cruciate ligament disruption in addition to collateral ligament disruption.
In knees with coronal plane deformities that exhibit varus-valgus instability, the clinician must distinguish true ligamentous insufficiency from pseudolaxity. For example, varus knees with osteoarthritis typically exhibit articular cartilage and bone loss in the medial compartment. Laxity to varus stress could represent lateral collateral ligament insufficiency or rotation of the tibia into varus as the medial femoral condyle settles into the defect in the medial tibial plateau. Conversely, laxity to valgus stress may represent correction of varus alignment as the tibia rotates back to neutral position. Inability to passively correct a coronal plane deformity may indicate the presence of long-standing disease with secondary medial or lateral soft tissue contracture that requires release at the time of reconstruction.
Neurologic and Vascular Evaluation
The neurovascular status of the affected extremity must not be neglected. Neurologic evaluation should include muscle testing, sensory examination, and assessment of deep tendon reflexes. Prior inspection should have identified atrophy or loss of muscle tone in the thigh and leg. Strength testing is performed by resisted isometric contraction of all major muscle groups, including hip flexion, extension, and abduction; knee flexion and extension; and ankle dorsiflexion and plantarflexion. Sensation can be evaluated by testing light touch, paying special attention to deficits in a dermatomal distribution. Deep tendon reflexes can be tested at the knee and ankle. The patellar reflex is predominantly an L4 reflex, and the Achilles reflex is an S1 reflex. Vascular assessment must include examination of the skin for signs of peripheral vascular disease, such as smooth shiny skin with hair loss, skin and subcutaneous soft tissue atrophy, and ulcerations. Palpation of peripheral pulses should include femoral, popliteal, posterior tibial, and dorsalis pedis pulses.
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