There are two bones in the forearm: the Radius and Ulna. The ulna is a long straight bone that does not rotate and acts as a mechanical strut for the wrist and elbow. The radius is slightly shorter and has a gentle bow along its course. The radius is responsible for the rotating motion of the forearm as is rotates around the ulna at the elbow and wrist. Unlike ulnar shaft fractures, radial shaft fractures almost always require repair and have been referred to as “the fracture of necessity” in orthopaedic texts because of the need for surgical repair to obtain a good result. Alignment and length of the radius is critical for wrist function as the radius rotates around the ulna. If left untreated, displacement or shortening of the radius results in marked limitation of rotation of the wrist. The most common mechanism of injury is a direct blow to the radial border of the forearm. These are relatively common injuries in adults.
Fractures of the upper end of the radial shaft present a separate challenge for surgeons repairing these fractures. One of the nerves that controls finger and wrist extension, called the posterior interosseous nerve (PIN) sits directly against the bone and can easily be damaged during surgical exposure. In cases of proximal radius fractures the surgeon spends extra time to dissect out the nerve completely and protect it during the surgical repair. This results in a larger surgical incision but this is completely warranted to avoid any nerve damage. The x-rays below demonstrate a proximal fracture where the PIN is at risk for damage.
Treatment involves realigning the bone and securing it with a plate and screws. Surgical repair can be performed as an outpatient. After surgery, patients wear a split (soft cast) for about 2 weeks and then begin a fairly aggressive protocol with physical therapy to regain range of motion in the forearm. Recovery is generally fairly quick and most patients regain full function within 8-12 weeks after surgery.