HOW TO DO KNEE EXAMINATION

 

HOW TO PERFORM KNEE EXAMINATION


Being a physical therapist it is very challenging to examine a patient. In this article we will be learning that how can a Physical Therapist examine a patient with knee injury. We will learn what are the special tests which can be performed on the patient. What are the knee movements and how can we diagnose any knee pathology considering these tests.

Knee Examination

              

Posture with patient standing

Observe any deformities such as genu varum, genu valgus or genu recurvatum . Note any evidence of muscle atrophy, particularly evident in the vastus medialis muscle. Observe the relative positions and size of the patellae. ‘Patella alta’ is the term used to describe a small high riding patella. Note any foot, ankle or subtalar deformity, such as foot pronation, which will cause medial rotation of the tibia and, hence, affect the mechanics of the knee joint.

                          

Swelling and discoloration

Swelling that extends beyond the joint capsule may suggest an infection or a major ligamentous injury, and the suprapatellar pouch will appear distended. Bruising may suggest trauma to superficial tissues or ligaments. Redness of the skin suggests an underlying inflammation. Palpate the temperature around the knee joint with the back of the hand: heat is indicative of an underlying inflammatory disorder.

Observe scar tissue that may be indicative of previous surgery or trauma.


Loss of muscle bulk

Observe loss of bulk in the quadriceps muscles, particularly in the vastus medialis which atrophies earlier than vastus lateralis following trauma, degenerative diseases and pain episodes. Measure the circumference of both thighs at 5, 8, 15 and 23 cm above the upper pole of the patella with a tape measure to obtain an objective marker (Magee 1992). Ask the patient to perform a static quadriceps contraction. Palpate the tone, compare left with right sides of the musculature. Inability to actively extend the knee may result from rupture of the quadriceps tendon or quadriceps weakness, patella fractures, rupture of the patellar ligament, or avulsion of the tibial tubercle. Note any loss of tone in the anterior and posterior tibial muscles and, again, measure, if appropriate, at specific recorded distances below the patella.


Patellar tap

Patellar tap is a simple test to determine the presence of an effusion at the knee joint. It is performed with the patient supine. Any excess fluid is squeezed out of the suprapatellar pouch by sliding the index finger and thumb from 15 cm above the knee to the level of the upper border of the patella . Then, place the tips of the thumb and three fingers of the free hand squarely on the patella and jerk it quickly downwards. A ‘click’ sound indicates the presence of effusion. The test will, however, be negative if the effusion is gross and tense, such as with a haemarthrosis of the knee (blood within the joint) following an anterior cruciate rupture.


Fluid displacement test

This is performed as above, by squeezing excess fluid out of the suprapatellar pouch and then stroking the medial side of the knee joint to displace any excess fluid in the main joint cavity to the lateral side of the joint. Repeat this procedure by stroking the lateral side of the joint. Any excess fluid will be seen to move across the joint and distend the medial side of the knee.

Tenderness at the knee (tibiofemoral joint)

Identify the joint line clearly by flexing the knee and observing for hollows at the sides of the patella ligament – these lie over the joint line.

  1. Tenderness at the joint line is common in meniscal and fat pad injuries.
  2. Tenderness along the line of the collateral ligaments of the knee joint is common at the site of a lesion following a tear, particularly at the upper and lower attachments, and at the ligament’s midpoint. Associated bruising and oedema may also be a feature of acute injuries.
  3. Tenderness at the tibial tubercle – in children and adolescents, tenderness and hypertrophy  of the tibial tubercle prominence – is associated  with Osgood Schlatter’s disease. Tenderness  is also found following acute avulsion  injuries of the patella ligament and its tibial attachment.
  4. Tenderness and swelling in the popliteal fossa may indicate the presence of a Baker’s cyst. This condition is associated with degenerative changes or rheumatoid arthritis involving the knee joint.
  5. Tenderness at the adductor tubercle may indicate strain in the adductor magnus muscle.
  6. Femoral condyle tenderness may indicate the presence of osteochondritis dissecans.

Patellofemoral joint assessment

A knee assessment should include assessment of both the tibiofemoral and patellofemoral joint. Observe the position of the patella and compare both sides.

  • Determination of a high or small patella (patella alta) is made by calculating the ratio  of the length of the patellar tendon to the  longest diagonal length of the patella. The normal value for this ratio is 1.02 ± 20% (Simmons and Cameron 1992). Patella alta is a predisposing factor in anterior knee pain and recurrent dislocation of the patella.
  • Observe any tilting, lateral glide and rotation of the patella during a quadriceps contraction. Compare this with the other side.
  • McConnell (1996) described a ‘critical test’ for the patellofemoral joint. Resisted inner­range quadriceps contraction is performed with the patient sitting at various degrees of knee flexion to determine whether this reproduces the patient’s symptoms. Compare both sides .
  • The McConnell critical test may be repeated with the patella taped in the corrected position. This will determine whether the taping is effective and should be incorporated into the treatment programme. Taping is believed to enhance activation and earlier timing of vastus medialis in quadriceps contractions and thus restore patellar tracking to normal.
  • Observe any excessive pronation of the feet which may increase the Q angle
  • Test for tightness in the following structures: lateral retinaculum, iliotibial band, hamstrings and calves. Tightness of the above structures will increase dorsiflexion and therefore pronation of the foot and ankle during the gait cycle. All of this will increase the Q angle (Olerud and Berg 1984).
  • Perform passive accessory movements to test the mobility and pain response of the patella in all directions. Observe pain, laxity or muscle spasm.  Perform Clarke’s test. The patient is asked to contract the quadriceps while the patella is pressed firmly down against the femur. Pain is produced in conditions such as chondromalacia or osteoarthritis affecting the patellofemoral joint

 


Movements

Active movements

The patient is in half lying. Measure the active range of flexion and extension on each leg. The normal range of movement at the knee joint is approximately minus 5 degrees to 135 degrees of flexion. Note limitations of pain, stiffness or spasm. Overpressure the movement if full active movement is pain­free. The axis of the goniometer should be positioned over the lateral femoral condyle. The static arm should be parallel with the long axis of the femur towards the greater trochanter. The dynamic arm should be positioned parallel to the long axis of the fibula and lateral malleolus . Hyperextension is present if the knee extends beyond 0 degrees (i.e. when the tibia and femur are in line). Failure to hyperextend or lock out the knee fully may be a sign of a meniscal tear that is blocking the movement of the joint. Moreover, a springy end­feel may be indicative of a bucket­handle tear of the meniscus. A rigid block  to extension is common in arthritic conditions affecting the knee.

Passive movements

 Check the range of extension and flexion passively. If there is a difference in active and passive range determine reasons for this.


Valgus stress test (medial collateral ligament  of the knee)

With the patient supine, the physiotherapist applies a valgus force to the knee joint (i.e. the femur is pushed medially, and the leg pulled laterally) while the joint is held in extension . A positive sign is observed as excessive opening up on the medial side of the joint. With the knee held in extension, a positive sign suggests major ligamentous injury involving the medial collateral, posterior cruciate and potentially the anterior cruciate. The test is performed again with the knee in 20–30 degrees of flexion.

Varus stress test (lateral collateral ligament  of the knee)

With the patient supine, the physiotherapist applies a varus force to the knee joint (i.e. the femur is pushed laterally, and the leg pulled medially) while the joint is held in extension . A positive sign is observed as excessive opening up on the lateral side of the joint. As with the valgus stress test, with the knee held in extension a positive sign suggests major ligamentous injury involving the lateral collateral, posterior cruciate and, potentially, the anterior cruciate. The test is performed again with the knee in 20–30 degrees of flexion.



Anterior draw test (anterior cruciate ligament)

 With the patient crook lying, the physiotherapist sits on the patient’s foot to stabilise the leg and grasps around the proximal tibia and tibial tuberosity and pulls the tibia forwards. A positive sign is elicited by excessive translation of the tibia anteriorly (the normal translation is approximately 6 mm). Translation of 15 mm confirms rupture. Compare this with the other side. This test also stresses the posterior joint capsule, the medial collateral ligament and the iliotibial band (Magee 1992).


Posterior draw test (posterior cruciate ligament)

With the patient crook lying, the physiotherapist sits on the patient’s foot to stabilise the leg and grasps around the anterior aspect of the proximal tibia and pushes the tibia backwards. A positive sign is elicited by excessive translation of the tibia posteriorly. Compare this with the other side. This test also stresses the arcuatepopliteus complex, posterior oblique ligament and anterior cruciate ligament (Magee 1992).


Lachman’s test (modified anterior draw test)

The patient is supine with the knee resting over the physiotherapist’s thigh at around 20–30 degrees of flexion. The physiotherapist grasps around the medial proximal aspect of the tibia with the right hand. The lateral aspect of the patient’s femur is stabilised by the therapist’s left hand. Anterior and posterior translation of the tibia is produced by the physiotherapist’s right hand. This tests the anterior cruciate, the posterior oblique ligament and the arcuate­popliteus complex (Magee 1992). The Lachman test has been shown to be sensitive for the diagnosis of anterior cruciate injury (Kim and Kim 1995).


The pivot shift test

This is a test for anterolateral instability of the knee joint. With the foot in medial rotation and the knee in 30 degrees of flexion, a valgus stress is applied to the knee while simultaneously extending it. A ‘clunk’ indicates a positive test and suggests anterior cruciate ligament pathology (McRae 1999).

McMurray’s medial and lateral meniscus tests

The physiotherapist palpates the medial aspect of the joint line, and passively flexes and then laterally rotates the tibia, so that the posterior part of the medial meniscus is rotated with the tibia. The joint is then moved back from a fully flexed position to 90 degrees of flexion to test for the posterior part of the meniscus. A positive test occurs if pain is elicited, or a snap or click of the joint will occur if the meniscus is torn. The test is then repeated for the lateral meniscus by medially rotating the tibia. Note that the examiner may be able to detect clicking or snapping sounds when performing this test, as there are various structures in the knee joint that can produce these signs. It is thus easy for this test to produce a false­positive result (Palmer and Epler 1998).


Apley’s compression/distraction test (for differentiation between meniscus and ligament)

 The patient is prone with the knee flexed at right­angles. The physiotherapist medially and laterally rotates the tibia while applying a distraction force through the knee joint. The test is repeated by applying a compressive force through the knee joint. If the patient’s symptoms are worse on compression then the symptoms are likely to be arising from a meniscal injury. Conversely, if they are worse on distraction then they are likely to be arising from a ligamentous injury. Proprioception Proprioception is tested with the patient standing on the unaffected leg and then on the affected leg while maintaining balance. Progressive adaptations may include standing on one leg with the eyes closed, standing on a wobble board, catching and throwing a ball, etc. Accessory movements Patellofemoral joint

  • Medial, lateral, cephalad and caudad glides.
  • Medial and lateral rotation.
  • Compression and distraction. Superior tibiofibular joint
  • Anteroposterior and posteroanterior glides.
  • Compression. Tibiofemoral joint
  • Anteroposterior and posteroanterior glides.
  • Medial and transverse glides. Quadrant tests These are performed on non­irritable knees when plane movements are pain­free.
  • Flexion/adduction quadrant.
  • Flexion/abduction quadrant.
  • Extension/adduction quadrant.
  • Extension/abduction quadrant.

Following the objective assessment record your findings clearly and asterisk objective markers.

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