Extensor Tendon Injuries An extensor tendon injury is a damage to the tissues on the back of the hand and fingers. It can make it hard for you to extend your wrist, open your hand, or straighten your fingers. The inability to perform these functions can severely limit hand and upper extremity function. Activity that requires repetitive motion of the forearm such as painting, typing, weaving, gardening, lifting heavy objects, and sports. Overuse of the forearm muscles. Direct trauma as a fall, work injury, or motor vehicle accident. The extensor carpi radialis brevis (ECRB) and longus, extensor digitorum, extensor digiti minimi, and extensor carpi ulnaris come together to form the common extensor tendon. The extensor carpi radialis brevis is almost always the primary tendon involved. Cuts that split the tendon may need stitches or surgical repair, but tears caused by jamming injuries are usually treated with splints. Splints stop the healing ends of the tendons from pulling apart and should be worn at all times until the tendon is fully healed. If you tear (rupture) or cut (sever) the tendon anywhere along its route—at the wrist, in the palm of the hand, or along with the finger, you may be unable to bend your finger. If you injure the FDS tendon, you may still be able to bend the finger, but not completely, and bending the finger will be painful Other Names Extensor tendinopathy Causes Generally a loss of ability to extend the affected digit, hand, and/or wrist Superficial, susceptible to injury The most common finger is the pointer/ index finger Potential mechanisms are sharp object direct lacerations, burns, blunt trauma, bites, crush injuries, avulsions and deep abrasions Can affect MCPJ and/or PIPJ or DIPJ of hand Zone 1: Traumatic flexion of DIPJ Zone 2: Dorsal laceration or crush injury Zone 5: Fight bite Fractures Phalanx Fractures (Hand) Metacarpal Fractures Boxer’s Fracture Rolando Fracture Bennett Fracture Dislocations Metacarpophalangeal Joint Dislocation Proximal Interphalangeal Joint Dislocation Distal Interphalangeal Joint Dislocation Carpometacarpal Joint Dislocation Tendinopathies Extensor Tendon Injuries (Hand) Central Slip Extensor Tendon Injury Flexor Tendon Injuries (Hand) Boutonniere Deformity Swan Neck Deformity Jersey Finger Mallet Finger Trigger Finger De Quervains Tenosynovitis Ligament Injuries Gamekeepers Thumb (UCL) Radial Collateral Ligament of the Thumb Injury (RCL) Volar Plate Avulsion Injury Neuropathies Wartenberg’s Syndrome Carpal Tunnel Syndrome Guyon Canal Syndrome Arthropathies Carpometacarpal Arthritis Finger Arthritis Rheumatoid Arthritis Nail Bed Injuries Nail Bed Lacerations Nail Bed Avulsions Subungual Hematoma Paronychia Felon Pediatric Considerations Proximal Phalanx Avulsion Fracture (Thumb) Middle and Distal Phalanx Avulsion Fracture Other Dupuytrens Contracture You Might Also Read Distal Myopathy and DysferlinopathySymptoms Inability to straighten the fingers or extend the wrist. Pain and swelling in the fingertip. Recent trauma or laceration to the hand. Drooping of the end joint of the finger. Diagnosis General: Physical Examination Hand Universally present with inability to extend at some point on the dorsal finger, hand, or wrist Inspect for etiology (laceration, crush trauma, overuse, etc) Zone 1: Loss of extensor mechanism at DIPJ (digits 2-4), IJP (thumb) Zone 3: Elson’s Test can help confirm a diagnosis Standard Radiographs Hand Consider ultrasound MRI in complex injuries Classification Zone 1: DIPJ Injury to terminal extensor tendon distal to or at the DIPJ (digits 2-4) or IPJ (thumb) involving EPL Sequelae: Mallet Finger Zone 2: Middle Phalanx Injury of tendon over middle phalanx (digits 2-4), or proximal phalanx thumb Zone 3: PIPJ Injury over the PIPJ of digit 2-4 leading to Central Slip Injury or MCPJ of thumb involving EPL, EPB Sequelae: Boutonniere Deformity Zone 4: Proximal Phalanx Injury over the proximal phalanx (digits 2-4) or metacarpal of thumb (EPL, EPB) Zone 5: MCPJ Injury over MCPJ of digit (2-4) or CMCJ of thumb (EPL, EPB) Sequelae: Fight Bite, Sagittal band rupture Zone 6: Metacarpals Injury over the metacarpal Sequelae: Increased risk of neurovascular injury Zone 7: Wrist Injury at wrist joint Surgical injury requiring repair of the extensor retinaculum Zone 8: Distal third of the forearm Disruption at the distal forearm Zone 9: Muscle belly rather than tendon injury Sequelae: High risk of neurologic injury, requires surgery Treatment Nonoperative Depends on the zone of injury Immobilization if <50% of tendon cut and extensor tendon remains intact DJ extension splint Zone 1 (mallet finger) PIPJ extension splint Zone 3 (central slip if simple) MCPJ extension splint Zone v (closed, uncomplicated sagittal band rupture) You Might Also Read Nerve Compression Syndromes - Causes, Symptoms, TreatmentOperative Incision & drainage: Open fracture involving joint, fite bite Repair: tendon laceration >50% Fixation: volar avulsion fracture Reconstruction: tendon repair not possible Central slip reconstruction