10.78. Posterior cruciate ligament (2):
With the leg still in 20° flexion, ask the patient to lift the heel from the couch while you observe the knee from the lateral side. Any posterior subluxation should normally correct during this extension of the knee, confirming the diagnosis.
10.79. Posterior cruciate ligament (3):
Place the thumb on one side of the joint line and the index on the other to help you assess any tibial movement. Try to pull the tibia forwards with the other hand. If the posterior cruciate ligament is torn and the tibia subluxed posteriorly, the forward movement as the tibia reduces will be easily felt.
10.80. Posterior cruciate ligament (4):
If the posterior cruciate is lax or torn, but subluxation has not yet occurred (uncommon), then backward pressure on the tibia will normally produce a detectable, excessive posterior excursion. Note that a Lachman procedure in the prone position may also be used to detect posterior cruciate laxity.
10.81. Posterior cruciate ligament (5): Dynamic posterior shift test: Flex both the knee and hip to 90°. The latter leads to hamstring tightening, which in the presence of ligament laxity leads to posterior displacement of the tibia. Now extend the knee: this displaces the axis of the pull anteriorly, and the displaced tibia will reduce. This is usually obvious to careful inspection and is indicative of posterior laxity, with or without additional posterolateral laxity.
10.82. Radiological examination of posterior cruciate ligament function (1):
A sandbag is placed behind the thigh and the proximal tibia pressed forcibly backwards (with an equivalent force of 25 kg). This is repeated, and after the second preloading cycle, radiographs are taken while the same force is maintained.
10.83. Radiological examination of posterior cruciate ligament function (2):
The gap between the medial femoral and tibial condyles is measured, along with that between the lateral condyles. A displacement of the order of 8 mm on each side is indicative of an uncomplicated posterior cruciate tear. Excessive movement on the lateral or medial sides indicates posterolateral or posteromedial instability.
10.84. Visualization of the cruciate ligaments: MRI scans allow an accurate assessment of the state of the cruciate ligaments in 80% of cases. (Note that in terms of accuracy this is inferior to clinical assessment.) (Illus: intact anterior cruciate ligament.) The cruciates may also be inspected by arthroscopy. The ability of the cruciate ligaments to prevent abnormal tibial movements can be assessed mechanically by dynamic testing rigs.
10.87. Losee pivot shift test for anterior subluxation of the lateral tibial condyle: The patient should be completely relaxed, with no tension in the hamstrings. Apply a valgus force to the knee (1) at the same time pushing the fibular head anteriorly (2). The knee should be partly flexed. Now extend the joint (3). As full extension is reached, a dramatic clunk will occur as the lateral tibial condyle subluxes forwards (if rotatory instability is present). Note: the patient should relate this to the sensations experienced in activity.
10.85. Assessing tibial subluxations (rotatory or torsional instabilities):
(1) Look for medial or lateral tenderness or oedema. (2) Perform the drawer tests noting variations. (3) Test for laxity on valgus stress (often positive in anterior subluxations of the medial tibial condyle). (4) Test for laxity on varus stress (usually positive when the lateral tibial condyle subluxes forwards or backwards). (5) Carry out the following additional tests.
10.88. Modified pivot shift or jerk test for anterior subluxation of the lateral tibial condyle: Grasp the foot between the arm and the chest, and apply a valgus stress (1); lean over to rotate the foot internally (2). Now flex the knee. If the test is positive, and because the tibia is firmly held, the lateral femoral condyle will appear to jerk anteriorly. Now extend the knee, and as the tibia subluxes the femoral condyle will appear to jerk backwards.
10.86. Macintosh test for anterior subluxation of the lateral tibial condyle (the pivot shift test): Fully extend the knee while holding the foot in internal rotation (1). Apply a valgus stress (2). In this position, if instability is present the tibia will be in the subluxed position. Now flex the knee (3): reduction should occur at about 30° with an obvious jerk. A positive test indicates an anterior cruciate abnormality, with or without other pathology.
The posterolateral drawer test: The knee should be flexed to a little less than 90° and the foot placed in external rotation. Apply backward pressure on the tibia. Excessive travel on the lateral side is indicative of posterolateral instability. Posterolateral instability is usually associated with injuries to the posterior cruciate and lateral ligament complex.
10.90. Posterolateral instability (2): The external rotation recurvatum test:
With the patient in the supine position, stand at the end of the examination couch and lift the legs by the great toes. The test is positive if the knee falls into external rotation (a), varus (b) and recurvatum (c).
10.91. Posterolateral instability (3): Jakob's reversed pivot shift test: Begin by flexing the knee to 90° (a). Now externally rotate the foot (b). apply a valgus stress (c), and extend the knee (d). If the test is positive, the posteriorly subluxed lateral tibial plateau suddenly reduces at about 20°.
10.92. Posterolateral instability (1): Standing apprehension test: The patient should be taking his weight through the slightly flexed knee. Grasp the knee and with the thumb at the joint line press the anterior part of the lateral femoral condyle medially. The test is positive if movement of the condyle occurs (allowing the tibia to slip posteriorly under it), and if this is accompanied by a feeling of giving way.
10.93. The menisci: (1): Look for tenderness in the joint line and test for a springy block to full extension. These two signs, in association with evidence of quadriceps wasting, are the most consistent and reliable signs of a torn meniscus.
10.94. The menisci (2): In recent injuries, look for telltale oedema in the joint line. Bruising is not a feature of meniscal injuries.
10.95. The menisci (3): Posterior lesions (1): Fully flex the knee and place the thumb and index along the joint line. The palm of the hand should rest on the patella. You are now in a position to be able to locate any clicks emanating from the joint.
10.96. The menisci (4): Posterior lesions (2): Sweep the heel round in a U-shaped are, looking and feeling for clicks from the joint accompanied by pain. Watch the patient's face, not the knee, while carrying out this test.
10.97. The menisci (5): Anterior lesions: Press the thumb firmly into the joint line at the medial side of the patellar ligament. Now extend the joint. Repeat on the other side of the ligament. A click, accompanied by pain, is often found in anterior meniscus lesions.
10.98. The menisci (6): McMurray manoeuvre for the medial meniscus:
Place the thumb and index along the joint line to detect any clicks. Flex the leg fully; externally rotate the foot, abduct the lower leg, and extend the joint smoothly. A click arising in the medial joint line, accompanied by complaint of pain, is indicative of a medial meniscus tear.
10.99. The menisci (7): McMurray manoeuvre for the lateral meniscus:
Repeat the last test with the foot internally rotated and the leg adducted. Use the hand to pick up the source of any clicks which are accompanied by pain. A grating sensation may be felt in degenerative lesions of the meniscus.
10.100. The menisci (8): If any clicks are detected, the normal limb should be examined to help eliminate symptomless, non-pathological clicks which may be arising from tendons or other soft tissues snapping over bony prominences (e.g. the biceps tendon over the femoral condyle), or from the patella clicking against a femoral condyle.
10.101. The menisci (9): If a unilateral painful click is obtained, repeat the test with the sensing finger or thumb removed. The cause of the click, whether from meniscus or tendon, may be visible on close inspection of the joint line.
10.102. The menisci (10): Apley's grinding tests (1): In the tests, the suspect meniscus is subjected to compression and shearing stresses; sharp pain is suggestive of a tear. The patient is prone. The examiner grasps the foot, externally rotates it and fully flexes the knee (1). He then internally rotates the foot and extends the knee (2). The sides are compared. This demonstrates any limitation of rotation, or where any pain occurs.
10.103. The menisci (11): Grinding tests (2): Then, while standing on a stool, the examiner throws his weight along the axis of the limb, and externally rotates the foot. Severe sharp pain is indicative of a medial meniscus tear. Repeat in a greater degree of flexion to test the posterior horn. To test the lateral meniscus, repeat the tests with the foot forcibly internally rotated.
10.104. The menisci (12): Meniscal cysts lie in the joint line, feel firm on palpation, and are tender on deep pressure. Cysts of the menisci may be associated with tears. Lateral meniscus cysts are by far the commonest. Cystic swellings on the medial side are sometimes due to ganglions arising from the pes anserinus (insertion of sartorius. gracilis and semitendinosus).
10.105. The patella (1): Examine both knees flexed over the end of the couch. This may show a torsional deformity of the femur or tibia, and a laterally placed patella (a) (which will be predisposed to instability (e.g. recurrent dislocation) or chondromalacia patellae). Now ask the patient to extend the knees (b). and look for any gross disturbance of patellar tracking: it should move smoothly in the patellar groove.
10.106. The patella (2): Look for genu recurvatum and the position of the patella relative to the femoral condyles. A high patella (patella aha) is a predisposing factor in recurrent lateral dislocation of the patella.
10.107. The patella (3): Is there any knock-knee deformity? Because this leads to an increase in the Q angle (quadriceps angle) it predisposes the knee to recurrent dislocation, anterior knee pain and chondromalacia patellae. The deformity is particularly common in adolescent girls. The intermalleolar distance may be measured, or the Q angle (which is similar to the tibiofemoral angle) may be determined.
10.108. The patella (4): Finding the Q angle: this is the angle (normally about 6°) between (i) a line joining the anterior superior iliac spine with the centre of the patella, and (ii) the line of the patellar ligament. Ask the patient (who must be standing) to hold the end of a tape measure on his anterior spine while you centre the other over the patella. Then align a goniometer with the tape and the patellar ligament.
10.109. The patella (5): Look for tenderness over the anterior surface of the patella, and note whether a tender, bipartite ridge is present. Lower pole tenderness occurs in Sinding-Larsen-Johannson disease. (Tenderness may also occur over the patellar ligament, quadriceps tendon and tibial tuberosity in other extensor apparatus traction injuries and variants of 'jumper's knee'.)
10.110. The patella (6): Displace the patella medially and palpate its articular surface. Tenderness is found when the articular surface is diseased, e.g. in chondromalacia patellae. Repeat the test, displacing the patella laterally. Two-thirds of the articular surface of the patella are normally accessible in this way.
10.11 1. The patella (7): Test the mobility of the patella by moving it up and down and from side to side. Reduced mobility is found in retropatellar arthritis. The quadriceps must be relaxed for adequate performance of this test. Decreased patellar mobility will obviously impair the performance of the previous test.
10.112. The patella (8): Move the patella proximally and distally, at the same time pressing it down hard against the femoral condyles. Pain is produced in chondromalacia patellae and retropatellar osteoarthritis.
10.113. The patella (9): The apprehension test: Try to displace the patella laterally while Hexing the knee from the fully extended position. If there is a tendency to recurrent dislocation, the patient will be apprehensive and try to stop the test, generally by pushing the examiner's hand away.
10.114. Articular surfaces (1): Place the palm of the hand over the patella, and the thumb and index along the joint line. Flex and extend the joint. The source of crepitus from damaged articular surfaces can then be detected. Compare one side with the other. If in doubt, auscultatc the joint. Ignore single patellar clicks.
10.115. Articular surfaces (2): Apparent broadening of the joint and palpable exostoses occur commonly in osteoarthritis. (Both sides of the joint are affected in the later stages of tibiofemoral osteoarthritis, but in the early stages of this condition the medial side of the joint is often affected first, leading to a bowleg deformity and frequently laxity of the medial ligament.)
10.116. Popliteal region (1): Nearly all the tests previously described have involved examination of the joint from the from. Do not forget to examine the back of the joint, by both inspection and palpation. If the knee is flexed the roof of the fossa is relaxed, and deep palpation becomes possible.
10.118. The hip: Always examine the hip. especially in the presence of severe, undiagnosed pain, as hip pain is often referred to the knee joint. The hip may be screened by testing rotation at 90° flexion and noting pain or restriction of movements.
10.119. Radiographs (1): Normal anteroposterior radiograph of the knee.
10.117. Popliteal region (2):
Semimembranosus bursae become obvious when the knee is extended. Compare the sides. A bursa may be small at the time of examination, and transillumination is worth trying although not always positive. Note that semimembranosus bursae may be secondary to rheumatoid arthritis or other pathology in the joint.
10.120. Radiographs (2): The contours of the femur, tibia and fibula are obvious. The patellar shadow is usually rather faint and difficult to make out. Note on the medial side the two tibial shadows formed by the anterior and posterior rims of the concave medial tibial plateau. (The lateral tibial plateau is convex and has a single shadow.)
10.121. Radiographs (3): Normal lateral radiograph of the knee. The arrow points to the condylopatellar sulcus, which helps identify the lateral femoral condyle, which is larger and tlatter.
10.122. Radiographs (4): Note here that the lateral condyles of the femur and of the tibia are drawn with a heavy line. The lateral tibial condyle may often be identified by the fibular articulation. The outline of the medial tibial condyle tends to blend with the shadow of the tibial spines. Note the fabella. an inconstant sesamoid bone lying in the lateral head of gastrocnemius: do not mistake it for a loose body.
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