Traumatic lesions at the thumb base: Treatment options.

Traumatic lesions around the base of the thumb have special features due to the location and structure of the joint and its inherent potential instability. This causes different fracture patterns, which are mostly isolated around the metacarpal base but can also involve just the trapezium or both. Exceptionally, there may be isolated dislocation. Fracture patterns are variable and influence the type of surgery. The most common fracture is Bennett's fracture accounting for 4% of all hand fractures and sometimes associated with trapezium fracture, usually in male subjects. Different fracture mechanisms have been proposed. Apart from intra-articular fractures of the metacarpal base and the trapezium, proximal metaphyseal fractures can exceptionally be treated conservatively by immobilization. All other fractures require open or closed reduction combined with different types of temporary pinning or open reduction and internal fixation with screws or locking plate in case of comminution. Immobilization depends on the type of surgical treatment and can be removable or non-removable. Close follow-up is mandatory to avoid the inconveniences of secondary swelling with non-removable plaster and resin casts. Extra-articular malunion may be tolerated, but articular malunion must be corrected surgically by intra-articular osteotomy to restore the joint. In case of posttraumatic joint degeneration, treatment will focus on a case-by-case basis on the patient's complaints. Arthrodesis or prosthetic surgery can be proposed in case of severe problems caused by osteoarthritis.