Posterior interosseous nerve compression by a synovial cyst in Frohse's syndrome - A rare case report

Background: Frohse syndrome is a very rare upper limb compression syndrome. It is caused by compression of the posterior interosseous nerve at the arcade of Frohse. It is clinically diagnosed, by a low paralysis of the radial nerve, a deficit of extension of the fingers, a radial deviation of the wrist, and a complete wrist extension. Additional paraclinical investigations will be conducted to determine the cause of the compression. The treatment is almost always surgical and consists of a neurolysis of the posterior interosseous nerve at the elbow. Case report: The authors report a case of posterior interosseous nerve compression at the arcade of Forhse by a synovial cyst, a very rare localization with a favorable prognosis., We followed the patient in the short and medium term, After six months, the patient started progressive recovery of the active extension of his fingers. Conclusion: Ignoring the posterior interosseous nerve palsy syndrome may lead to a diagnostic error and the outcome of this operation depends on the observed nerve damages.