Teaching Case

A 32 year old female presented with a rigid left middle finger with no visible skin crease over the DIP joint. Discuss the relevant investigations, the possible diagnosis and the management of the case.

Patient was referred by her GP for a consultation regarding a rigid left middle finger, which she'd had since birth. On examination it was noted that the left middle finger was of normal length but there was no skin crease over the DIP joint, and clinically no movement was possible at the joint. An X-ray revealed fusion of the DIP joint.

Symphalangism is a rare congenital disorder in which there is fusion of the interphalangeal joints.Involvement of the DIP joint is sporadic but PIP joint involvement has been described with a number of congenital anomalies and the mode of inheritance is autosomal dominant. The associated anomalies include spinal, carpal and tarsal fusion as well as conduction deafness. The patient usually presents with a stiff finger. Examination will reveal absence of skin creases over the affected joint (Fig 1). Radiologically, the findings are bony ankylosis(Fig 2), minimal joint space and sometimes the digit is shorter than normal. In a patient with distal symphalangism,no treatment is recommended to restore motion to the DIP joint, as the dysfunction is not significant.