Carpal bone fractures

Injury mechanisms and pathomechanics

Disruption of bone tissue integrity in this area most commonly occurs due to direct physical impact—for example, from a heavy blow with a hammer or stick, or a heavy object falling onto the hand. Indirect injury mechanisms are recorded significantly less often.

A key feature of such injuries is secondary fragment displacement, which develops under the constant action (pull) of contracting interosseous and lumbrical muscles. The direction of the resulting angle strictly depends on the level of injury:

• Metacarpal bones: muscle pull leads to the formation of a deformity with an angle open palmward.
• Phalanges: under the action of the same muscle groups, the fragments are displaced in such a way that an angle open dorsally is formed.

Clinical presentation and diagnostics

Patients present with complaints of acute pain and limitation of both active and passive movements. Visually, pronounced swelling on the dorsum of the hand, diffuse edematous changes, and a subcutaneous hematoma directly over the fracture zone are determined.

A specific and highly reliable clinical test is the axial loading sign: if the physician gently presses along the longitudinal axis of the metacarpal bone or finger, the patient notes a sharp increase in pain within the defect zone.

When displacement is present, shortening and visible deformation of the damaged segment are observed, as well as pathological mobility of the bone fragments. The palpation picture has clear differences depending on the anatomical zone:

1. In injuries of the metacarpal bones, the protruding apices of the fragment angles are easily palpated on the dorsal side of the hand, whereas on the palmar surface, a characteristic depression is determined.
2. In injuries of the phalanges, the picture is mirrored: the bone prominence is localized on the palmar surface, and tissue depression is on the dorsal side.

Final verification of the diagnosis is always carried out based on hand radiography in two projections.

Algorithm of therapeutic measures

Patient management tactics are structured depending on the radiographic picture and the success of conservative maneuvers.

For non-displaced fractures, immediate conservative therapy is indicated: a plaster splint is applied for a period of 3–5 weeks.

For displaced fractures, the following step-by-step algorithm is used:

• Step 1: Closed manual reduction. Performed under local anesthesia. The technique consists of traction of the finger along the bone axis with simultaneous pressure on the apex of the deformity angle (palmward) and on the metacarpal head (dorsally). If successful, a dorsal or palmar plaster splint is applied for 4–5 weeks.
• Step 2: Skeletal traction. This method is indicated if secondary fragment displacement has occurred after primary successful reduction.
• Step 3: Surgical treatment. If closed reduction or skeletal traction proves ineffective, open reduction with osteosynthesis (using K-wires, screws, or plates) or pin fixation is performed. Surgery (arthrodesis) is also indicated in case of failed treatment of an intra-articular comminuted Rolando fracture.

Immobilization and rehabilitation

The correct boundaries of the plaster cast are critically important to eliminate pathological mobility:

• For metacarpal bones: the splint is applied from the upper third of the forearm to the middle of the fingers.
• For phalanges: fixation is carried out from the lower third of the forearm to the very fingertips.

The total duration of immobilization ranges from 3 to 6 weeks. After cessation of immobilization, the active rehabilitation period begins, including exercise therapy (physiotherapy exercises), physical therapy modalities, massage, and therapeutic baths. Full functional recovery and return to work typically occur 5–6 weeks after the injury.

Class and exam questions

What else to study on this topic

• Technique of closed reduction in fractures of the tubular bones of the hand
• Features of the comminuted intra-articular Rolando fracture
• Biomechanics of interosseous and lumbrical muscles in hand injuries
• Types of osteosynthesis used in hand surgery (K-wires, plates, screws)

Other topics in the "Specialized Adult Traumatology" section

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