Background: Polydactyly is considered to be one of the common congenital hand anomalies. Classification of congenital hand anomalies by Swanson groups similar forms of deficits affected by specific embryological failures. Each type of polydactyly has its separate classification. This case series suggested classification that could include the radial and ulnar variants of polydactyly in one classification and direct the management in algorithmic approach.
Methods: Case series of 11 cases, who were diagnosed with polydactyly of the hand consecutively at King Abdulaziz Medical City in Jeddah, Saudi Arabia. Cases were described by physical assessment and x-ray, then categorized by the proposed MAS classification.
Results: Description of 11 cases by the suggested MAS classification: A- Soft tissue attachment. B-Bone attachment. I. Attached to metacarpal bone. II. Attached to the proximal phalanx. III. Attached to the middle phalanx. IV. Attached to the distal phalanx. C- Joint attachment. I. Attached to carpometacarpal joint. II. Attached to metacarpophalangeal joint. III. Attached to the proximal interphalangeal joint. IV. Attached to the distal interphalangeal joint. Treatment according to the algorithmic approach: type A, treat it with soft-tissue excision; type B, bony excision with or without reinsertion of abnormal muscle attachment; and type C, excision of collateral ligaments and reconstruction with or without K wire fixation and reinsertion of abnormal muscle attachment.
Conclusions: MAS classification demonstrates a potential to be applied to both ulnar and radial polydactyly. It is simple, easy to recall, anatomically and surgically oriented for practical purposes. Thus, it needs to be validated in extensive studies.