The metacarpals form the frame of the palm. They are five long bones which connect the wrist to the fingers, and are divided into three parts (base, diaphysis and head). They are the “protagonists” of the most common hand injuries as they are particularly susceptible to direct collisions or axial compressions - studies indicate that they account for 18-44% of hand fractures. Although one or more bones may be affected during the injury, resulting in transverse or spiral fractures, the 1st (thumb) and the 5th metacarpal bones are most commonly injured.
HIGH RISK GROUPS
According to global epidemiological data, the high-risk groups include the active population, and more specifically, adolescents and young adults. In the US alone, each year, the metacarpal fractures result in more than 16 million days of absence from work and another 90 million days of limited activity!
The most common injury mechanisms is punching a hard surface (which is why the fourth and fifth metacarpal head fracture is called the “boxer’s fracture”), the fall from a height and crushing. The most severe ones are considered those which are the result of a traffic accident, the injuries from agricultural machinery or an occupational accident, as there is a crush injury in the hand with multiple fractures, strains and / or muscle and tendon injuries.
WHICH ARE THE SYMPTOMS?
The most common symptoms are pain (automatic or under pressure), swelling in the dorsal surface, deformity, and the inability of the palm to close or hold objects, as the finger (or fingers) can not move. Because the metacarpal bones are located subcutaneously, skin injuries are often concomitant.
WHICH IS THE BEST TREATMENT?
The fractures at the base of the metacarpals, namely, where a joint with the corresponding bone of the distal end of the wrist is formed, except for the thumb, if there are no rotational deformity, they can be treated conservatively. This means: immobilization in a splint for 3-4 weeks and a gradual mobilization, to prevent stiffness. The majority of them also include the fractures in the diaphysis of the metacarpal bones - it is about the point which serves for the adhesion of muscles, tendons and ligaments. In this case as well, the conservative treatment with the application of a dorsal plaster splint has a highly beneficial effect.
However, given the location of the metacarpal bones, even small dislocations may lead to a shortening or a rotational deformity, namely, to crooked fingers. Therefore, conservative treatment is only indicated in individual cases, and certainly not in fractures that are, by definition, displaced and unstable, such as those at the base of the thumb, the juxta-articular fractures of the 1st metacarpus and those at the base of the little finger. Generally, all cases where there is an extensive bone crush and deformity require surgery for a closed or open resetting and an osteosynthesis with needles, screws or plates.
WHAT IS A “BOXER’S FRACTURE”?
A “boxer’s fracture” are quite frequent, although studies have shown that they rarely occur in those specific athletes. It is about a particular type of injury as, according to the literature, can be treated conservatively under the basic condition that the dorsal angulation is small. Thus, a reinforced dressing for 3-4 weeks may be sufficient. However, in larger angulations, or in rotational deformities, surgery should be performed, for the resetting and stabilization of the fracture.
It is worth mentioning that, these days, orthopedic surgeons have access to modern osteosynthesis materials, which repair even comminuted fractures, while the majority of them do not require a removal. In any case, regarding the surgical or non-surgical treatment of the fracture, the doctor shall consider the type and extent of displacement and professional activity of the patient. A fundamental principle is that, in the future, the patient’s hand should be fully functional.