The Albright-Losee Low Profile Pivot Shift Test for ACL Deficiency

Abstract

Background: Recognizing ACL injuries on the field and in the office can be very challenging in awake and apprehensive patients. Despite high specificity, many published "pivot-shift" techniques have limited acceptance mainly because of unsatisfactory sensitivity. We describe in detail, four specific modifications and provide a critical review of our clinical experiences to empower the new user's readiness to master a novel screening procedure for ACL disruption.

Methods: 18 cadavers assessed instability kinematics of the novel technique. Clinical Exam Study Part II-A (ACL Disrupted): 208 awake, hemarthrosis patients with MRI evidence of ACL deficiency underwent 363 examinations by 41 examiners. Clinical Exam Study Part II-B: (ACL Intact) 47 consecutive posttraumatic hemarthrosis patients with intact ACLs underwent 76 examinations by 30 examiners.

Results: Cadaveric study confirmed patterns of coupled, anterior translation-internal rotation pathologic laxity at 25.6±8.2 degrees flexion. Clinically, the novel test yielded sensitivity of 94.7% and Specificity of 97.3%. Potentially perplexing situations included: MRI availability; pain and anxiety-related traumatic hemarthrosis, protective hamstring antagonism and examiners experience.

Conclusion: When the examiner and patient agree on a feeling of instability, the Albright-Losee Test maximizes ability to establish ACL status in the awake patient to the point that the sensitivity is even greater than the Lachman Test. Armed with background knowledge of our experiences confirms that, despite of impact of various challenging factors, the Positive Predictive Value 98.8% 95% CI (95.5%-99.7%) that a torn ACL exists in face of a positive exam confirms its value for sports medicine providers to master. Level of Evidence: II.

Keywords: ACL; ACL rupture; anterior cruciate ligament; office examination.

Figure 1

Hand Placement: palm down with while radial fingers (index to ring) stabilize the anterior aspect of the distal femur above patella and ulnar side of thumb against posterior aspect of fibular head. The thumb provides gentle anterior force on the fibula of 1-3 lbs. as the knee is extended from flexion towards full extension without intentional valgus. The endpoint is reached when the examiner recognizes.

Figure 2

The endpoint occurs with index finger and thumb detection of pathologic lateral tibial translation anteriorly. As the examiner detects subluxation occurring, motion is stopped, and the patient is asked if they feel their knee is “out of place”. If the patient does not agree; a gentle, isotonic application of valgus force of 2-5 lbs. is applied in that potentially subluxed position to enhance proprioception. If they still can’t acknowledge the abnormality of the position; the test is recorded as “equivocal”.

Figure 3

Example of a single trial LP-LPST for ACL intact and deficient conditions on the same specimen. Coupled internal rotation and anterior translation are higher in the ACL deficient condition when compared to the ACL intact condition for both the exit and re-entry pivot. A true pivot sees anterior translation couple with concurrent high internal rotation.

Figure 4

Example of a single trial LP-LPST for ACL intact and deficient conditions on the same specimen. Coupled internal rotation and anterior translation are higher in the ACL deficient condition when compared to the ACL intact condition for both the exit and re-entry pivot. A true pivot sees anterior translation couple with concurrent high internal rotation.