Pivot Shift Test

Pivot shift test is a manipulative and provocative test for demonstrating the rotatory subluxation that is often associated with anterior cruciate ligament injury.

This test was first described by Galway et al.¹ in 1972 and has been described since by a number of authors.

See Also: Anterior Cruciate Ligament Injury

How do you perform the Pivot Shift Test knee?

• The patient is placed in supine position with the hip flexed to 45º and the knee fully extended.
• The examiner grasps and immobilizes the lateral femoral condyle with one hand and palpates the proximal tibia or fibula with the thumb.
• With the other hand, the examiner holds the patient’s lower leg in internal rotation and abduction (valgus stress).
• From this starting position the knee is then moved from extension into flexion.

What does a positive Pivot Shift Test mean?

• In the presence of a torn anterior cruciate ligament, the valgus stress will cause the tibia to subluxate anteriorly while the knee is still in extension. The blockade of the knee in anterior subluxation depends on the degree of valgus stress applied.
• The knee is then flexed while the same internal rotation and abduction of the lower leg is maintained; this then causes the subluxated tibial head to reduce posteriorly at 20 to 40° of flexion.
• The patient usually confirms the diagnosis by reporting that the typical sensation of the knee giving way felt in sports activities can be reproduced in this test.
• The best site to observe this reduction is at the tubercle of Gerdy.

A false pivot shift test may be present in:

1. generalized ligament laxity,
2. iliotibial band injury,
3. a buckle handle tear of the meniscus.

Sensitivity & Specificity

In a meta-analysis ² that looked at 28 studies to assess the accuracy of clinical tests for diagnosing ACL ruptures, Benjaminse et al. found the pivot shift test to be very specific both in acute as well as in chronic conditions, and recommended that both the Lachman test and pivot test be performed in all cases of suspected ACL injury:

• Sensitivity: 24 %
• Specificity: 98 %

Another comparative study found that the Pivot Shift Test has a sensitivity of 81.8% and specificity of 98.4%.

Notes

• A positive pivot test result is always dependent on an intact iliotibial tract because the iliotibial tract (which with increasing flexion glides from a position anterior to the lateral epicondyle in extension to a position posterior to the axis of flexion) draws the tibial head posteriorly again.

• The pivot shift test will be inaccurate if knee extension is not possible because of pain, swelling, or displaced meniscal tear.

• The pivot test can be elicited more easily when the examiner immobilizes the patient’s leg between his or her own forearm and waist while applying slight axial compression.

• In an anterior cruciate tear, both the medial and lateral portions of the tibia migrate anteriorly under the stress of the anterior drawer.

• In an isolated tear of the anterior cruciate ligament, the anterior motion of the lateral portion of the tibia will be more pronounced than that of the medial portion.

• The anterior motion of the medial portion of the tibial plateau increases relative to that of the lateral portion as the number of injured medial structures increases. Increasing anterior motion of the medial tibial plateau in turn increases the severity of the subluxation and subsequent reduction phenomenon observed by the examiner. This reduction will also be observed to occur at an increasingly high degree of flexion.

• In ACL deficiency, the femur falls posteriorly due to gravity. Tis results in apparent anterior dislocation of the tibia with respect to the femur. The pivot shift test demonstrates relocation of the internally rotated tibia about the MCL when the knee is moved with the application of a sustained valgus torque. It is demonstrable in chronic ACL deficiency, and as for any stability test, the prerequisite is a completely relaxed patient.

• Carefully palpate the margin of the lateral tibial plateau in relation to the distal femoral condyle to avoid confusion with the anteromedial tibial subluxation.

According to Jakob, a genuine pivot shift phenomenon can partially disappear, despite anterior cruciate ligament insufficiency, under the following conditions:

1. When a complete tear of the medial collateral ligament is present, the valgus opening prevents force concentration in the lateral compartment. Subluxation cannot occur under these circumstances.
2. When the iliotibial tract is traumatically divided, only the subluxation will be observed, not the abrupt reduction.
3. A bucket-handle tear of the medial or lateral meniscus can prevent anterior translation or reduction of the tibia.
4. Increasing osteoarthritis in the lateral compartment with osteophytes can create a concave contour along the once convex lateral tibial plateau.

Jakob Graded Pivot Shift Test

Gradation of the pivot shift test allowing for translation and rotation of the tibia.

The procedure is identical to the pivot shift test except that here instability of the knee is assessed with the lower leg not only in internal rotation but also in neutral and external rotation.

Pivot shift grade I:

• The pivot shift test is positive only in maximum internal rotation; it is negative in neutral and external rotation.
• The subluxation as the knee approaches extension is more palpable than visible to the examiner (slight translation m ay be apparent).

Pivot shift grade II:

• The pivot shift test is positive in internal and neutral rotation; however, it is negative in external rotation.
• There is visible and palpable translation on the lateral aspect of the joint.

Pivot shift grade III:

• The pivot shift test is clearly positive in neutral rotation and particularly conspicuous in external rotation.
• The sign is less distinct in internal rotation.
• Pivot shift grade III can only be demonstrated in acute knee injuries where the posteromedial and lateral structures are damaged in addition to the anterior cruciate.
• In chronic instability, a grade III pivot shift will be detectable in cases where the secondary stabilizers have loosened
  over time.

Modified Pivot Shift Test

How do you perform the Modified Pivot Shift Test?

The patient is supine. With one hand, the examiner holds the patient’s lower leg in internal rotation while the other hand grasps the tibial head laterally and holds it in a valgus position.

In a positive Modified Pivot Shift Test , this alone will produce anterior subluxation of the lateral tibial head. The rest of the procedure is identical to the pivot shift test.

Subsequently flexing the knee while maintaining internal rotation and valgus stress on the lower leg causes posterior reduction of the subluxated tibial head at about 30° of flexion.

The test is performed with the femoral head in abduction and adduction and in each case with the lower leg in external and internal rotation.

The iliotibial tract plays an important role in subluxation as the knee approaches extension and in subsequent reduction as flexion increases in the pivot shift test. The initial stress present in the iliotibial tract greatly influences the severity of subluxation. The iliotibial tract is relaxed in hip abduction, whereas it is under tension in hip adduction.

In patients with an insufficient anterior cruciate ligament, subluxation is therefore more pronounced in hip abduction than it is in hip adduction, The iliotibial tract contributes directly and indirectly (passively) to stabilizing the lateral knee.

The portion of the iliotibial tract between the fibers of Kaplan and Gerdy’s tubercle can be regarded as a passive ligament like structure that is placed under tension by the proximal portion of the tract that runs through the thigh. The tension in this passive femorotibial portion of the tract determines the degree of subluxation of the tibial head.

Internally rotating the lower leg and adducting the hip tenses the entire iliotibial tract, which increases tension in the ligament like portion that spans the knee. This tension will prevent anterior subluxation of the tibial head during the pivot shift test in the presence of a torn anterior cruciate ligament.

However, externally rotating the lower leg reduces the tension in the portion of the iliotibial tract that spans the knee, allowing greater anterior subluxation of the tibial head. The degree of subluxation is even greater when the leg is abducted.

Soft Pivot Shift Test

The patient is supine. The examiner grasps the patient’s foot with one hand and the calf with the other. First, the examiner alternately flexes and extends the knee carefully, using these norm al everyday motion sequences to alleviate the patient’s anxiety and reduce reflexive muscle tension. The patient’s hip is abducted, and the foot is held in neutral or external rotation.

Next, the examiner gently applies axial after about 3 to 5 flexion and extension cycles. With the hand resting on the calf, the examiner applies a mild anterior stress

Under axial compression and mild anterior stress, slight subluxation will occur as the knee approaches extension, with reduction occurring as flexion increases. By varying the speed of the flexion and extension cycle, the axial com pression, and the anteriorly directed pressure, the examiner can precisely control the intensity of the subluxation and subsequent reduction. In this test, the examiner literally feels his or her way toward the subluxation and reduction.

The soft pivot shift test ensures reduction with minim al pain or even with no pain at all. Carefully performed, this test can be repeated several times without the patient’s complaining of pain.

Medial Shift Test

The examiner immobilizes the patient’s lower leg between his or her forearm and waist to evaluate the medial or lateral translation (tibial displacement) as the knee approaches extension. To assess medial translation, the examiner places one hand on the lower leg slightly distal to the medial joint cavity while the other hand rests on the lateral thigh. While applying a valgus stress to the knee via the lower leg, the examiner presses medially with the hand resting on the patient’s thigh.

In an anterior cruciate tear, the tibia can be displaced medially until the intercondylar eminence comes in contact with the medial femoral condyle. Because the posterior cruciate ligament courses from medial to lateral, lateral translation of the tibial head will be detectable in the presence of a posterior cruciate tear (positive lateral pivot shift test).

Reference

1. Galway HR, MacIntosh DL. The lateral pivot shift: a symptom and sign of anterior cruciate ligament insufficiency. Clin Orthop Relat Res. 1980 Mar-Apr;(147):45-50. PMID: 7371314.
2. Benjaminse A, Gokeler A, van der Schans CP. Clinical diagnosis of an anterior cruciate ligament rupture: a meta-analysis. J Orthop Sports Phys Ther. 2006 May;36(5):267-88. doi: 10.2519/jospt.2006.2011. PMID: 16715828.
3. Katz JW, Fingeroth RJ. The diagnostic accuracy of ruptures of the anterior cruciate ligament comparing the Lachman test, the anterior drawer sign, and the pivot shift test in acute and chronic knee injuries. Am J Sports Med. 1986 Jan-Feb;14(1):88-91. doi: 10.1177/036354658601400115. PMID: 3752353.
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