Article
Acute Compression of the Median Nerve at the Elbow by the Lacertus Fibrosus: Biomechanical Translation from Partial Rupture of the Biceps at the Myotendinous Junction
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Authors
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William Seitz
- Cleveland Clinic, Cleveland, United States
| Published: | February 6, 2020 |
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Outline
Text
Objectives/Interrogation: Patients with acute partial distal biceps rupture develop acute median nerve compression due to a shift of the Lacertus Fibrosis.
Methods: A series of 18 consecutive cases of acute median nerve compression in the antecubital fossa is presented resulting from an extremely forceful injury to the elbow. In all cases, a sudden severe attempt at elbow flexion was performed against a severe counter force resulting in immediate severe pain radiating from the elbow down to the forearm. The pain was severe, persistent and unremitting and worsened with passive elbow extension and forearm pronation. Duration of symptoms was 3-16 months until definitive diagnosis was made. Multiple diagnosis including "elbow strain", medial and/or lateral epicondylitis were erroneously entertained and patients were treated with a variety of modalities unsuccessfully prior to definitive treatment. Surgical decompression was performed in all cases.
Results and Conclusions: Evidence was found at the time of surgery of partial rupture of the distal myotendinous junction of the biceps brachii creating increased tension across the median nerve by a tethered lacertus fibrosis. Common characteristics found in all cases included: identifiable forced flexion injury against resistance; severe unremitting pain from the time of injury especially with resisted elbow flexion, passive extension and pronation, or direct compression over the antecubital fossa; evidence of partial rupture of the distal myotendinous junction of the biceps at surgery; and prompt complete persistent relief of symptoms following surgical decompression.
Awareness of the potential for acute compression of the median nerve by the lacertus fibrosis following a severe flexion injury can prevent erroneous diagnosis and improper treatment. It can help the treating surgeon differentiate this entity from the more chronic forms of compressive neuropathy. Surgical decompression provides definitive management with a predictably effective outcome.
