When you see a fracture, think of it in terms of the variables in Fig. 69-5. Is it closed, or is there a tear in the skin over it, so that it is open (compound)? Spiral fractures have pointed tips, heal rapidly, and are caused by forces acting along the length of a limb, which remains fairly stable. Transverse and oblique fractures take longer to heal than spiral ones, and are caused by forces acting across a limb, which becomes unstable. Oblique fractures have rounded tips, heal particularly slowly, and have all the disadvantages of a transverse fracture, with the added one that you cannot easily get the fragments to hitch (73-13). Angulation can be anterior or posterior, the lower fragment can be in varus (directed towards the midline) or in valgus (directed away from it). Overlap is not always as undesirable as you might think (78.1), but always avoid distraction because, if the ends of two fragments do not touch, they may never unite.
Occasionally, the fragments are impacted into one another in a suitable position, so that you can preserve the impaction, as in some fractures of the necks of the humerus or the femur. Unfortunately, the fragments are usually in an unsatisfactory position, so that an important first step in reducing most fractures is to disimpact the fragments by pulling them apart.
A ligament can be sprained and only partly torn, or it can be completely ruptured. In a dislocation the joint surfaces are widely displaced, but in a subluxation they are still partly touching one another. Both subluxations and dislocations are often combined with fractures.
Fractures and dislocations differ greatly in the urgency with which you must treat them. Reduce all dislocations and fracture dislocations immediately, because the longer you leave them, the tighter the ligaments will become, and the more difficult or impossible your task. If a dislocation is likely to be difficult to reduce, use a relaxant. With most fractures you have more time, and the best time to reduce a fracture is either immediately after the injury, before the tissues have started to swell, or up to a week later (not more), after the swelling has gone. If you are referring a fracture for internal fixation, the sooner the patient reaches the referral hospital the better. He should at least be there within two weeks.
Some fractures and dislocations are much more common than others, but the rarer ones are no less important to the patients who have them, and are not necessarily any more difficult to treat. The common ones are extension fractures of the wrist, clavicle fractures, supracondylar fractures of the humerus in children, fractures of both forearm bones in children, fractures of the shaft of the humerus in adults, fractures of the tibia and fibula either alone or combined, fractures of the shaft of the femur, fractures of the radius and ulna, and fractures of the metatarsals and metacarpals. Most other fractures are rare.