gms | German Medical Science

Introduction: Kaplan dislocation is described as the blocked palmar displacement of the second metacarpal head in the ligamentous and tendinous structures, which generates an eyelet mechanism that limits the reduction with conventional techniques. This presentation is very rare in children and the lack of knowledge makes treatment difficult that can lead to complications derived from inadequate management.

Objectives: To evaluate clinically the pediatric patients with diagnosis of Kaplan dislocation and propose a new reduction technique in the pediatric population.

Methods: Retrospective Case Series study. Six male patients were evaluated, with an average age of 9.3 years. All of them underwent the proposed reduction maneuver (rotation and ulnar deviation). Clinical and radiological follow-up was performed at 6 months.

Results: In five of six (83%) patients, the proposed closed-reduction maneuver was performed successfully: hyperextension of the index MF while performing rotation and concomitant ulnar deviation of the joint. One of the patients required an open reduction by palmar approach. Post-reduction mobility evidenced almost complete arcs in all patients. There were no complications associated, presence of joint stiffness or instability.

Conclusions: Kaplan dislocation in children is not frequent. The classical maneuver of reduction is just successful in around 10 - 20 % of the cases. Closed-reduction should be attempted with the proposed maneuver that seeks to reject the volar plate of the MF joint to facilitate its reduction. Its success rate is high, as 83% if it is done early (less than 72 hours). This maneuver is a very good management option with very good clinical and functional results.