Pediatric Hand Injuries

Fractures in pediatric population occur due to crush, twisting and bending forces such as hyperextension or hyperflexion. One should be aware of rotational malalignment. Loss of any of the following two suggests malrotation: 1) when flexed all fingers should point towards the scaphoid tuberosity; 2) when the fingers are adducted, semiflexed and viewed end-on, the nails lie in the same plane.

Fractures in phalanges can be located in the head, neck, shaft or the base. Head and base fractures are usually intra-articular. Neck and shaft fractures can be transverse, oblique, spiral and comminuted. Bending forces cause transverse or oblique fractures, torsional forces cause spiral fractures, and crushing forces cause comminuted fractures. If the fracture is undisplaced or if it is stable after reduction, it can be treated by a splint that immobilizes the involved joint as well as the immediately proximal and distal ones. Sometimes, buddy strapping the finger to the adjacent uninjured one suffices. If the fracture is displaced or angulated more than 100, it usually requires open reduction and internal fixation with crossed K wires or plates and screws.

Distal phalanx fractures are usually associated with nailbed injuries. The fibrous septae of the pulp stabilize fragments. This on one hand reduces displacement but may work adversely to keep fragments apart leading to nonunion. These fractures can be treated conservatively with a gutter splint or thimble splint. If comminuted and associated with an open wound, unattached fragments can be excised. Loss of the distal half of the shaft may lead to a hooked nail deformity.

Mallet finger can be seen with an avulsion fracture of the terminal slip of the extensor mechanism. The distal phalanx adopts a dropped position and cannot be actively extended. These may be associated with an injury to the proximal epiphysis. Anatomic reduction is essential and is achieved either by closed or open methods. Suitably molded splints that keep the DIP joint in extension may maintain reduction. Occasionally, internal fixation with a K wire may be needed.

Jersey Finger is an avulsion fracture of the insertion of the flexor profundus tendon into the distal phalanx. The avulsed fragment may lie as far proximally as in the palm. This almost always requires open reduction and internal fixation with a mini screw or K wires.

Metacarpal Fractures

Metacarpal fractures can occur at the head, neck, shaft and base. Neck fracture of the 5thmetacarpal is called “Boxer’s fracture”. Head fractures are usually due to axial compression forces. This involves the epiphysis in all metacarpals except the thumb. In the thumb metacarpal, the epiphysis is distal while it is proximal in all other metacarpals.

Often isolated shaft and neck fractures of the middle and ring finger metacarpals do not require splinting as they are immobilized quite adequately by the other intact metacarpals. In other metacarpals a splint can treat undisplaced fractures with the hand in the universal position of immobilization. Displaced and unstable fractures can be fixed with K wires or plates & screws.

A special fracture in this category is a fracture of the base of the thumb metacarpal, which is called Bennet’s injury. This involves the epiphysis and generally requires internal fixation with smooth K wires. If undisplaced, can be treated by a splint with the hand in the universal position of immobilization. Often isolated fractures of the middle and ring finger metacarpals do not require splinting as they are immobilized quite adequately by the other intact metacarpals. Displaced and unstable fractures can be fixed with K wires or plates & screws.

Carpal Fractures

The scaphoid is the most common carpal bone to be involved. The cartilaginous nature of the carpus provides a certain amount of resilience that protects most other carpal bones from injury. Obtaining radiograms of the opposite side and looking for asymmetry is especially important in carpal injuries. Considerable force is required to fracture the relatively resilient carpal bones in children. Hence, associated metacarpal or ligamentous injuries are quite often seen. Almost all carpal fractures can be treated conservatively by splinting the wrist in 200 to 300 of dorsiflexion. If indicated, internal fixation is achieved with smooth K wires.

Dislocations are described with reference to the distal bone involved. Most pediatric dislocations can be treated by closed reduction and splints that immobilize the injured joint as well as the ones proximal and distal to it. Occasionally, soft tissues may get caught between dislocated joint surfaces, which will necessitate UofL Health – Kleinert Kutz Surgery Center to explore the removal of the offending structure.

What are Fingertip and Nailbed Injuries?

Fingertip and nailbed injuries are among the most common hand injuries. They can result from numerous mechanisms including cutting injuries (with kitchen knives), crushing injuries (car doors, hammering, etc.) or by other accidents with saws or industrial machines. Several structures can be damaged at the tip of the finger. The nail, nailbed, pulp skin, bone and nerve endings are the structures that can be damaged with these types of injuries. When these injuries occur near the crease of the fingertip, the tendons can be damaged as well.

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Assessment and management of tendon injuries in children largely parallels that in the adult. Indirect indicators of tendon injury include: Loss of the normal flexion cascade of the digits. In a relaxed hand, all the fingers adopt a flexed attitude. The degree of this flexion progressively increases from the index to the little. If a flexor tendon is cut, that digit lies abnormally ‘extended’ compared to the others. Passively extending the wrist results in flexion of the fingers if the flexor tendons are intact. Similarly, passively flexing the wrist causes extension of the digits if the extensor tendons are intact. Squeezing the flexor or extensor muscle bellies in the proximal forearm causes a corresponding flexion or extension of the digits. Loss of this indicates tendon discontinuity.

The hand is placed in splints following tendon repairs. The splints are designed to limit the movement opposite to that which the tendon performs. Consequently, flexor repairs are placed in splints that keep the digits partially flexed and limit extension, while extensor repairs are placed in splints that limit flexion of the digits. This reduces strain on the sutures and protects the repair till the tendons are fully healed. UofL Health – Frazier Rehab Institute – Hand Therapy will implement an intensive physiotherapy regimen to restore good function after the tendons have been repaired.

The assessment and treatment of these injuries is largely similar to adults. The pediatric limb tolerates ischemia better than the adult limb. The digits may tolerate as long as 6-10 hours of warm ischemia and sometimes up to 24 hours of cold ischemia. The limiting factor is often the very small size of the pediatric neurovascular bundles, necessitating ultra-microscopic techniques.

Amputated parts have to be preserved by wrapping them directly in a waterproof polythene bag, which is then placed in another larger polythene bag containing ice. The amputated part must not come into contact with ice or any other liquid. If very contaminated, the amputated part can be thoroughly washed in sterile isotonic solutions like normal saline or lactated Ringer’s solution prior to packing.

The Sequence of Replanting an Amputated Digit Is

• Debridement of the part
• Identification of all the structures of the digit
• Shortening the bones to get a stable fixation as well as one that permits easy bridging of all the soft tissue structures.
• Fixing of the bones. If the digit is amputated through a joint, it is often better to trim off the articular cartilage and fuse the joint after appropriate bone shortening.
• Repair of tendons (both flexor and extensor)
• Repair of veins(at least 2 per digit)
• Repair of nerves
• Repair of arteries
• Closure of skin

Aftercare of the replanted digit required very meticulous monitoring for the initial week to detect and quickly intervene in the event of any compromise to its viability. Once viability of the digit is assured, UofL Health – Frazier Rehab Institute – Hand Therapy will implement intensive physiotherapy to restore function.