- Clinical science
Finger injuries are very common and because there are many different possible injuries, only some of the more common flexor and extensor tendon as well as ligament injuries will be covered here. Injury is typically caused by lacerations (work place injury, road traffic accidents) or blunt force (e.g., ball sports, falling). For instance, forced extension of the distal interphalangeal joint (DIP) can damage the flexor digitorum profundus (FDP) tendon and lead to a loss of DIP flexion (Jersey finger). Forced flexion of the DIP causes extensor digitorum (ED) tendon injury, which results in a loss of DIP extension (mallet finger). Rupture/slippage of the central band of the ED tendon is primarily due to laceration or blunt injury and results in a hyperextension of the DIP with flexion of the PIP (Boutonniere deformity). Sudden forced hyperextension and abduction of the metacarpophalangeal joint (MCP) of the thumb can tear the ulnar collateral ligament (UCL) and cause laxity (Gamekeeper's thumb). While all flexor tendon injuries need to be surgically repaired, most extensor tendon and some ligament injuries can be managed conservatively with splints. Complete laceration or no response to conservative therapy are indications for surgical repair. Postoperative complications of tendon or ligament injuries include adhesions, joint contractures, and chronic joint deformities (e.g., swan-neck deformity, chronic mallet finger). Early recognition and treatment of injuries and their complications is necessary to prevent permanent disability.
- Physical examination (see "clinical features" below)
- X-ray: three views are taken (posterior-anterior, oblique, and lateral) to identify coexistent fractures
- Ultrasound: can detect complete lacerations
- MRI: provides accurate description of the extent of tendon or ligament injury
|Affected tendon(s) or ligament(s)||Condition||Mechanism of injury||Clinical features||Treatment||Possible complications|
|Flexor digitorum profundus tendon||Jersey finger|| || || || |
|Extensor digitorum tendon||Mallet finger|| || || |
|Central band of extensor digitorum tendon||Boutonniere deformity|| || || |
Ulnar collateral ligament (UCL) of the thumb
|Gamekeeper's thumb (Skier's thumb)|| || |
The differential diagnoses listed here are not exhaustive.