Locked metacarpophalangeal joint is an uncommon phenomenon with many possible etiologies. Diagnosis can be difficult because of the many more common pathologies (trigger finger, sagittal band lesion, etc.) that can lead to a clinical picture that may resemble the locked metacarpophalangeal joint. Once the differential diagnoses have been eliminated, the etiology of this blockage must be determined and the surgical procedure must be oriented. The origin of the problem is often difficult to determine, especially since standard imaging tests are often not very informative. Several clinical forms are possible, with blockages in extension or flexion, but which will have a disabling functional impact on the overall function of the hand. Currently, there is no gold standard for the management of this condition. In this study, we performed a review of the literature in order to better understand the different possible etiologies but also to analyze the different diagnostic and therapeutic management. LEVEL OF EVIDENCE: IV.

We managed a case of locked metacarpophalangeal joint of the little finger in the extension position. Incarceration of a chronic osteochondral fracture fragment led to this unique condition. The fracture fragment partially adhered to the volar plate and ulnar collateral ligament on the joint side, which is supposed to have resulted in manually irreducible locking of the joint. We performed open reduction and achieved release of the locked joint by excising the fracture fragment.