Mannerfelt Syndrome Clinical Presentation

Updated: Apr 26, 2021
  • Author: Dimitrios Danikas, MD, FACS; Chief Editor: Harris Gellman, MD  more...
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The patient usually presents with a history of rheumatoid arthritis (RA) and loss of thumb interphalangeal (IP) joint flexion.


Physical Examination

Because the flexor pollicis longus (FPL) is the only muscle to flex the IP joint of the thumb, the Mannerfelt lesion is usually clinically apparent on physical examination. The examiner stabilizes the metacarpophalangeal (MCP) joint, and the patient is asked to flex the IP joint. In the case of rupture, the patient is unable to flex the distal thumb phalanx or, at most, is able to flex it weakly (see the image below).

Mannerfelt syndrome. Patient is unable to flex int Mannerfelt syndrome. Patient is unable to flex interphalangeal joint of thumb after spontaneous rupture of flexor pollicis longus tendon.

Incomplete anterior interosseous nerve paralysis and rupture of the FPL tendon resemble each other clinically. A simple and reliable test can differentiate the two conditions. [22]  The physician dorsiflexes the patient’s wrist. The thumb is hyperextended at both the carpometacarpal (CMC) joint and the MCP joint. If the FPL is intact but paralyzed, the IP joint flexes spontaneously and resists passive extension when tested. If the tendon is ruptured, the IP joint remains extended. [23]