1.1 Epidemiology

In the AO documentation (1980–1996) 10–14% of all fractures recorded occurred in the forearm. From 1996 to 2006, there has been a more than 200% increase in the volume of surgically treated forearm fractures [1].

1.2 Special characteristics

This injury may be associated with joint dislocation at either the proximal or distal aspects of the forearm.

Distal radioulnar joint (DRUJ) dislocation and radial shaft fracture is also known as a Galeazzi fracture. Radial head dislocation and proximal ulnar fracture is known as a Monteggia fracture.

Fractures and fracture dislocations can be associated with increased risk of forearm compartment syndrome. Nightstick fractures (isolated fractures of the ulnar shaft) are classically due to defense against blunt trauma. These fractures are associated with a high rate of delayed union or nonunion despite usually being a closed injury with a simple fracture pattern.

2.1 Case history and physical examination

A carefully obtained history provides valuable information, eg, if the injury occurs in a dirty environment. Common mechanisms of injury include falls from height, motor vehicle collisions, sports injuries, and direct blows to the forearm.

Symptoms typically include pain, swelling, deformity of the forearm, and decreased forearm and elbow motion.

Physical examination often reveals swelling, ecchymosis, deformity, and tenderness to palpation. There may be crepitus at the fracture site and palpable deformity at a proximal or distal joint dislocation.

Flexion and extension of the elbow, pronation and supination of the forearm, as well as wrist flexion, extension, radial and ulnar deviation should be gently assessed during physical examination. Assessment of the radial and ulnar pulses, as well as median, ulnar and radial nerve function is critical.

Inspect for open fractures, wrist and elbow stability, tense forearm compartments, and neurovascular injuries.

2.2 Imaging

Conventional x-rays of the forearm in two planes are usually sufficient. They must include the elbow and wrist to exclude associated articular fractures or fracture dislocations, and specific fracture types, such as Monteggia, Galeazzi, or Essex-Lopresti type fractures. A computed tomographic scan or magnetic resonance imaging is rarely required. If the amount of deformity cannot be clearly quantified, a x-ray of the contralateral forearm as a comparison view can be helpful.

4.1 AO/OTA Fracture and Dislocation Classification

The AO/OTA Fracture and Dislocation Classification of forearm fractures is based upon the location, morphology, and complexity of the fracture ( Fig 6.3.2-1 ).

4.2 Fracture dislocation

4.2.1 Monteggia fracture

A Monteggia fracture is a shaft fracture of the ulna, with an anterior or lateral dislocation of the radial head at the proximal radioulnar joint (PRUJ) ( Fig 6.3.2-2 ).

Early open reduction and fixation is necessary as closed reduction is difficult to obtain and hold, and delayed fixation compromises the functional outcome. If the ulna is correctly reduced and stabilized, the radial head reduces spontaneously in most cases. Pronation and supination are assessed clinically and with the image intensifier. If the radial head remains subluxed or dislocated, the most common cause is malreduction of the ulna. This must be assessed carefully and corrected. If the PRUJ remains unstable then surgical exploration is indicated. This can be performed either by a separate lateral incision for the radial head or by extension of the original surgical approach and detachment of the anconeus and supinator muscles at their ulnar insertions. Interposed articular fragments should be removed and the annular ligament may need to be repaired.

Postoperative treatment should be with full early motion or with a removable splint in supination for 3 weeks to allow controlled mobilization of the elbow [2].

4.2.2 Galeazzi fracture

A Galeazzi fracture is a fracture of the radial shaft with dislocation of the DRUJ. It has been termed the “fracture of necessity” describing the requirement for open reduction and internal fixation.

Correct reduction and fixation of the radial fracture is usually accompanied by spontaneous reduction of the DRUJ ( Fig 6.3.2-3 ). This must be carefully evaluated clinically and with image intensifier. If the ulnar head remains subluxed or dislocated, the most common cause is a subtle malreduction of the radial fracture. This must be diligently assessed and corrected as necessary. If the DRUJ remains reducible but unstable, the joint may be cross-pinned with 1.6 mm (in children) or 2.0 mm (in adults) K-wires with the forearm in neutral rotation or in slight supination [3]. In these cases, additional splinting of the forearm including elbow and wrist is mandatory to prevent rotation and wire breakage. However, gentle flexion and extension of the elbow may be performed under the supervision of a trained therapist. Exploration of the wrist by a dorsal approach is only recommended if closed reduction cannot be maintained. This usually occurs from an interposed extensor carpi ulnaris tendon.

4.2.3 Essex-Lopresti lesion

An Essex-Lopresti lesion is a proximal radial shaft or radial neck/head fracture combined with instability of the DRUJ [4]. Proximal migration of the radius tears the interosseous membrane and causes axial instability.

Anatomical reduction of the radial head, neck, or proximal shaft is crucial to ensure forearm stability. Even mild displacement of the proximal radius can create incongruity at the DRUJ. X-rays of the involved and contralateral wrist using an AP projection and neutral rotation will allow comparison of ulnar length. Reduction may be achieved with small lag screws, mini T-plates, or radial head replacement for radial head/neck fractures or plates 3.5 for shaft fractures.

Failure to address radioulnar instability at onset can result in persistent axial migration of the radius with DRUJ disruption that is extremely difficult to repair at a late stage ( Fig 6.3.2-4 ).

6.1 Timing of surgery

As with most diaphyseal fractures, closed forearm fractures are best operated on within the first 24 hours following the injury. Open fractures should urgently undergo debridement and irrigation and fixation. Prolonged delay in fixation may increase the risk of radioulnar synostosis [6].

6.2 Implant selection

Many years of clinical experience have proven that a plate 3.5 is the ideal size for forearm bones. In general, we recommend the limited-contact dynamic compression plate.

There should be six cortices or three bicortical screws in each main fragment. In simple fractures this usually means a 7-hole or 8-hole plate; in more complex fractures even longer plates are advisable.

Whenever possible an interfragmentary lag screw, inserted independently or through a plate hole, should be used. In general, 3.5 mm cortex screws are used as lag screws but in small fragments or small bones, 2.7 or even 2.4 mm screws are recommended. For most forearm fractures, nonlocking screws give good results and locking head screws are not commonly required.

The role of intramedullary locked nails is still to be defined as questions persist about their ability to control rotation. Elastic nails give excellent results in pediatric forearm diaphyseal fractures, but this mode of fixation does not give adequate stability for early range of motion in adults [7].

6.3 Operating room set-up

Sterile drapes are applied to ensure a waterproof environment for the operative site. Since a drape around the hand can be bulky, it may be more suitable to wrap the hand in a sterile stockinette fixed with an adhesive tape or a clear adhesive plastic drape ( Fig 6.3.2-5 ). The image intensifier is draped separately.

The surgeon sits facing the patient′s head, the assistant opposite, and the operating room personnel at the end of the arm table. Bring the image intensifier in from the assistant′s side of the arm table. The assistant has to move temporarily when imaging. Place the image intensifier display screen in full view of the surgical team and the radiographer ( Fig 6.3.2-6 ).