Bilateral ST-coalition with thumb hypoplasia and scaphoid synchondrosis.

Carpal coalitions are rare wrist anomalies and are most often diagnosed incidentally. Due to their infrequent occurrence, there is a lack of treatment guidelines in the literature. We present a case study of a 13-year-old boy who presented with symptomatic synchondrosis in both scaphoids along with a bilateral osseous coalition between the scaphoid and trapezium bones in combination with bilateral thumb hypoplasia. We initiated a 10-week immobilization of the wrist, followed by gradual increasing weight-bearing. The patient showed significant symptom relieve after immobilization, further supporting the conservative treatment. In conclusion, a definitive treatment recommendation cannot be made. For young patients, we suggest initiating conservative treatment as the first option. A precise analysis of the pathology and wrist kinematics is mandatory to recommend further therapy especially if operative interventions might be considered.