Alternative Methods of Management

Closed reduction with plaster immobilization has long been offered as adequate treatment for Bennett's fracture. It and other alternative treatments are summarized in Table 52—2. At 5 to 10 years of follow-up, several studies have shown that small

CARPOMETACARPAL JOINT INJURIES | Table 52-2 Alternative Methods of Management

Type of Management Advantages

Arthroscopic reduction and percutaneous fixation

Closed reduction and plaster immobilization

Closed reduction and percutaneous pinning

Open reduction and internal fixation

External fixation

Traction, both longitudinal and oblique

Minimally invasive; reduction under arthroscopic and radiographic visualization; stable fixation; early active motion; shorter recovery

Reduction and fixation under direct visualization; stable fixation Permits stable fixation of complex wounds, open fractures, and comminuted fractures; dynamic fixation may allow early active motion Oblique traction counteracts the distracting forces of the abductor pollicis longus; minimally invasive

Disadvantages

Technically demanding

High likelihood of loss of reduction, long term osteo-arthritis; potential loss of function Longer immobilization than arthroscopic reduction and percutaneous fixation

Greater operative exposure; increased risk of nerve or vascular injury Technically demanding surgery; higher risk of infection

Prolonged immobilization necessary; proper pin-care required

Comments

Cannulated screws beneath cortical bone maintain fracture reduction without causing soft tissue inflammation due to gliding of the tendons over exposed hardware Former standard of care; now reserved for stable fractures

Exposed Kirschner wires possible source of superficial and deep infection while implanted; rehabilitation cannot be started until pin removal Rehabilitation longer due to joint stiffness of open procedure Not commonly used for simple Bennett's fracture

Longitudinal traction not recommended, as vector of traction does not provide anatomic reduction

Noninvasive

Minimally invasive; greater stability than closed methods degrees of malunion resulted in relatively mild symptoms. Furthermore, although imperfect reduction did correlate with the degree of radiographic degenerative changes at follow-up, the radiographic changes did not predict the presence of symptoms. However, a report of patients treated conservatively followed for 26 years found significant pain, deformity, loss of strength, and loss of mobility. These authors like many of us today concluded that Bennett's fracture is not a benign injury, and that poor initial reduction predicts long-term complications.

The objective of surgical management is to achieve perfect reduction to prevent degenerative changes to the CMC joint. Though requiring greater skill on the part of the surgeon, exact anatomic reduction is the most reliable method of achieving consistently good results.

Closed Reduction and Percutaneous Pinning

Closed reduction of the thumb metacarpal is followed by double Kirschner-wire (K-wire) pinning of the base of the metacarpal to the trapezium. Care must be taken so as not to pin the ulnar-volar fragment. Reduction and fixation are checked by the image intensifier and confirmed by radiography. If the reduction is anatomic with less than 1-mm step-off, it is further maintained by plaster immobilization for 6 weeks followed by pin removal. If the reduction is not anatomic, open reduction and internal fixation are performed.

Open Reduction and Internal Fixation

Open reduction and internal fixation via the thenar surgical approach is often used for failures of closed reduction and pinning. The fracture is reduced and fixed with two K wires aligned transversely across the fracture fragments. A third wire is added, pinning the trapeziometacarpal joint. Surgeons skilled in the use of cannulated screws may prefer their use to K wires, as this technique will allow early mobility.

External Fixator

External fixation has been used primarily in the case of Rolando's fracture, which is a comminuted fracture through the base of the thumb metacarpal in a Y- or T-shaped pattern. Similarly, in the case of severe instability or a multiple digit injured hand, external fixation can be used to reduce a Bennett's fracture. The external fixator is applied to the fragments, traction is applied, and length and alignment are maintained by tension band wiring.

Traction, Both Longitudinal and Oblique

As stated above, the distracting forces of the abductor pollicis longus cause instability in Bennett's fracture. Traction can be used to counteract these displacing forces. A K wire is driven obliquely through the base of the thumb metacarpal, and traction is applied to the wire via an outrigger. The oblique angulation of the wire is designed to apply traction in two vectors. The first vector is along the axis of the thumb and prevents shortening of the shaft. The second vector is in the ulnar direction and is needed to correct the varus angulation.

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