Locked metacarpophalangeal joint of long fingers: classification, definition and treatment based on 15 cases and literature review

Objectives: The purpose of this study was to clarify the definition, classification and treatment of the disorder known as the locked metacarpophalangeal (MCP) joint of long fingers, through the analysis of 15 cases and a literature review.

Patients and methods: We carried out a retrospective study of 15 patients with locked MCP joint of long fingers, all treated between 1997 and 2007. All patients underwent some imaging investigations including lateral, anteroposterior and Brewerton X-ray examinations. All these patients had been treated by surgery, which allowed us to describe the concerned lesions.

Results: The patients were 47 years old on average, 70% of the locks involved the index and the middle finger. Twelve fingers were locked in flexion. In nine of these cases, the cause was a blocking due to a clinging of the radial or ulnar accessory collateral ligament that overlapped a prominent metacarpal condyle or an osteophyte of the metacarpal head. Three fingers were locked in extension due to an imprisonment of a strap of the palmar plate. One patient was lost to follow-up. The remaining 14 patients had an average follow-up of 12.6 months. All recovered normal mobility without any recurrence.

Conclusion: This study and the literature review show that there are in fact two clinical presentations depending on the etiologies. We suggest a modification of both Posner's definition and Harvey's classification; a new classification should focus on the causes depending on the clinical presentation of the locking, so as to improve the correlation between clinical presentation, etiology and treatment.