Article
The relative motion flexion test: Rationale for not using Elson’s Test to assess acute PIP joint trauma with uncertain progression into boutonniere deformity
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Published: | February 6, 2020 |
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Clinical issue/s: Elson's test is reported to be the most used of the standard assessment tests. The test maneuver is however, difficult to perform consistently and test results vary due to subject interpretation. Because the test is not sensitive to detect partial tendon tears, the method of testing may worsen the original trauma.
Clinical reasoning: Elson's test requires the examiner to position the PIP joint in maximum flexion, resist the patient's effort to extend the PIP joint and subjectively observe for a response at the DIP joint. The test is said to evaluate the status of the central slip after acute injury. The assumption is that injury of the central slip will result in boutonniere deformity. Biomechanical study has shown that structures thought critical for PIP joint extension (central slip, Winslow's triangular ligament and extensor hood fibers) were not as important contributors to boutonniere deformity as passive flexion of the PIP joint beyond 30°. This presentation will discuss the reasons for not using Elson's test including rationale:1) for not maximally flexing the PIP joint and 2) why Winslow' Diamond and intrinsic muscle input, not the central slip is more important to assess.
Innovative, analytical or new approach: The position of relative motion flexion (RMF) is offered as an alternative method for assessment of uncertain boutonniere deformity following acute closed injury of the PIP joint. The position of RMF is not a passive-resistive test that maximally flexes the PIP joint, instead uses balanced interplay between the extrinsic and intrinsic muscles is required. Most importantly assessment can be made to determine the dynamic capacity of Winslow's Diamond to extend the PIP joint.
Contribution to advancing HT practice: Correction of boutonniere deformity is a difficult challenge for both Hand Surgeons and Hand Therapists. If the methods of initially screening closed trauma of the PIP joint for potential deformity can be improved, perhaps this difficult to correct deformity can be better prevented.