Isolated fractures of the radial shaft (proximal two-thirds) are less common than distal radius fractures. These injuries usually occur from either a direct blow to the forearm or a fall on outstretched hands (FOOSH). Isolated radial shaft fractures require full evaluation and documentation of distal radial ulnar joint (DRUJ) stability. A radial shaft fracture with DRUJ instability is referred to as Galeazzi fractures. Both isolated radial shaft fractures and Galeazzi fractures require open reduction and internal fixation (ORIF) to achieve satisfactory outcomes.
The radius is the shorter of the two bones in the forearm and it lies lateral to the ulna. The radial shaft is mostly round in cross section with the exception of the interosseous margin or crest where the interosseous membrane attaches to the shaft. The radial shaft also has a slight curve producing a medial concave border.
Deforming forces on the radial shaft come from the brachioradialis which pull the distal fragment proximal and the pronator quadratus which pronates the fragment and pulls it proximal and volar. The thumb extensors can also shorten the shaft.
Diagnosis of a radial shaft fracture comes from a history, physical examination and AP and lateral radiographs of the elbow, forearm and wrist. The elbow and wrist need to be evaluated for associated injuries including ligamentous instability such as the Galeazzi pattern described above. Range of motion of both the wrist and elbow should be pain free in the specific joint.
Radiographs aid in identifying the location of the fracture and assist in treatment plans including surgical approach.
Non-operative treatment of radial shaft fractures is rare and outcomes of nonsurgical treatment in the past have been poor (see Outcomes below). Nonetheless in the instance of nondisplaced radial shaft fractures, initial immobilization in a sugar tong splint is warranted as a treatment option. After swelling subsides a long arm cast can be implemented, but there is a risk of loss of motion at the elbow with this type of immobilization.
Open fractures with severe soft tissue injury in isolated radial shaft fractures (as opposed to both bone forearm fractures) may be initially treated with temporizing external fixation. Also the multi-trauma patient in extremis is another possible indication for damage control orthopaeidcs.
Generally the standard of care for radial shaft fractures is open reduction and internal fixation with 3.5mm dynamic compression plating is the treatment of choice. The surgical approach depends on a number of variables including fracture location. Fractures of the proximal radial shaft are most often approached dorsally with a Thompson approach, which can be extensile if necessary. Distal radial shaft fractures are usually approached through a volar incision. This volar approach of Henry is extensile as well.
Complications include compartment syndrome, malunion, nonunion, infection, neurovascular damage, and synostosis.
- Compartment syndrome should be suspected in all forearm fractures.
- Malunion can result from increased dorsal angulation or malrotation. Both can affect range of motion especially pronation and supination.
- Nonunion with plate osteosynthesis is a rare entity, but when present nonunion can be treated with ORIF and bone grafting.
- Infection in closed fractures is rare. These instances should be treated with irrigation and debridement. Hardware in these cases may be retained until bony union occurs.
- Radio-ulnar synostoses are extremely rare in isolated radial shaft fractures and more commonly seen in both bone forearm fractures by a crush mechanism.