Open Reduction and Internal Fixation of Forearm Fractures

Thomas F. Varecka, MD

Neither Dr. Varecka nor any immediate family member has received anything of value from or has stock or stock options held in a commercial company or institution related directly or indirectly to the subject of this chapter.

INTRODUCTION

The forearm is a unique regional structure within the musculoskeletal system. Not only does it serve as a platform for the origins and insertions of various muscle groups that produce elbow and wrist flexion and extension, it also has its own intrinsic motions—supination and pronation. Anatomically, the forearm serves as a gantry, helping the terminal functional unit, the hand, to be placed three dimensionally within a person’s environment to interact with their surroundings, thus facilitating the use of tools, self-care, and feeding, as well as independence. Injuries to the forearm have the potential to seriously impair these functions. Given the role of the radius and ulna as a platform for muscle function, restoring stable, pain-free continuity to these bones is essential. Because the forearm itself functions as a joint with its own motion, accurate anatomic restoration is mandatory.¹^,²^,³^,⁴^,⁵

Fractures of the forearm are infrequent, but not rare, with a reported incidence of approximately 14 forearm fractures per 100,000 population per year.⁶ This places the frequency of forearm fractures well below that of distal radius, femoral neck, and ankle fractures, but well above that of distal humerus, distal femur, and talus fractures.⁶ However, there does seem to be a trend toward an increasing frequency of diaphyseal forearm fractures related to falls, notably in younger females, with the rising rates of obesity and diabetes being suggested as possible contributing factors.⁷ As with most injuries of the appendicular skeleton, males predominate by roughly a 2:1 ratio. The average age of patients with diaphyseal forearm fractures is about 35 years, with a unimodal, left skewed distribution reflecting their predominance in the younger population.⁶

PATIENT SELECTION

As the dual roles of anatomic and articular function of the forearm became more appreciated, the need to achieve stable, rigid fixation of fractures of the forearm became widely accepted.¹^,²^,⁸^,⁹^,¹⁰ Consequently, treatment of these fractures almost always involves open reduction and internal fixation (ORIF), usually with plates and screws (Figure 1). Because fracture instability is frequently quite marked when both the radius and ulna are broken and because of the variety of deforming forces exerted by the various forearm muscles when the skeleton has been disrupted (Figure 2), an open reduction almost invariably is required to reestablish anatomic alignment.¹¹^,¹² Plating is accepted as the most reliable means of maintaining rigid alignment once the fractures have been reduced.¹³^,¹⁴

In addition to reducing the fractures of the radius and ulna, the surgeon also must pay attention to the proximal and distal radioulnar joints. Accurate and anatomic realignment of these articulations must be achieved if the forearm motions of supination and pronation are to be recovered. An accurate restoration of radial and ulnar diaphyseal anatomy usually will restore articular alignment by indirect means. Direct reduction of the proximal and distal radioulnar joints normally is not necessary, and accurate articular alignment generally can be assessed on intraoperative radiographs.

Few contraindications to ORIF of the forearm exist. In cases of severe skin compromise (such as that which occurs with burns) or extensive and severe contamination (such as that which occurs with fractures sustained in a farm setting), temporary stabilization of the fractures with an external fixator may be prudent. More simple open injuries with less extensive contamination are not in themselves contraindications to ORIF, even on an immediate basis.²^,¹⁵ Once the soft tissues or contamination has been addressed, however, proceeding with rigid internal fixation is indicated.

In addition to promoting recovery of forearm function, internal fixation has long been recommended as a means of allowing rapid recovery of the normal use and activity of the forearm, thus avoiding the development of so-called “fracture disease.”⁴ Fracture disease is the pathologic consequence of immobilizing normally mobile structures for long periods. It manifests as joint stiffness and pain, weakness from muscle deconditioning, hyperemia, skin atrophy, and allodynia.

Although less common today than when forearm fractures were routinely treated for extended periods in long arm casts, fracture disease still occurs. In its most egregious forms, fracture disease produces prolonged states of pain and disability and is termed complex regional pain syndrome.

FIGURE 1 AP radiographs show a typical both-bone fracture of the forearm before (A) and after (B) open reduction and internal fixation.

FIGURE 2 Radiographs show a both-bone forearm fracture. A, Lateral view shows the fracture before treatment, with malalignment and impending malunion. B, AP view shows the forearm following treatment with casting alone.

EVALUATION

The diagnosis of a forearm fracture usually is straightforward. Occasionally, a history of a fall on the outstretched arm or another form of indirect injury is reported. More frequently, however, patients endorse having sustained a direct blow to the forearm by a rigid structure such as a baseball bat, a steering wheel, certain immovable objects (eg, trees or fences), or contact with the ground. Not
uncommonly in urban environments, a gunshot injury is the cause. Pain, swelling, tenderness, and the inability to use the forearm are universal. When examining a patient with such a history, it is important to check for any associated openings in the skin, lacerations, or other evidence that the fracture may be open. Equally important and universally mandatory is the thorough evaluation and documentation of the patient’s sensory, motor, and circulatory status. Also important is the recording of the circumstances of the injury, such as at the workplace or as a result of a motor vehicle collision or an altercation.

PREOPERATIVE IMAGING

Standard radiographs should be obtained in the emergency department, with at least three separate projections—AP, lateral, and oblique—necessary to assess the fractures adequately for displacement, extent, comminution, presence of subcutaneous air (suggesting an open fracture), and presence of any foreign materials. These radiographs should routinely include the joints above and below (ie, the elbow and wrist) to exclude any involvement of these joints in the injury pattern. Rarely are special imaging techniques such as CT or MRI needed to establish the diagnosis of a both-bone forearm fracture.

PREOPERATIVE PLANNING

As with any challenging surgical exercise undertaken to fix a fracture, preoperative planning is highly recommended. A good preoperative plan should include an accurate drawing of the fracture(s) that details the position along the length of the bone, the degree of comminution and displacement, and the tentative location of any fixation devices. The position of all screws, including those to be placed outside the plates, should be indicated. Moreover, it is very helpful to generate a list of all equipment to be used in the order in which they will be used. All special devices should be noted, particularly when they may have to be procured from outside the hospital’s routine equipment supply. The plan should include the need for imaging machines and the approximate points along the course of the procedure that will require intraoperative imaging. Another important element of the plan is dressing requirements, such as plaster bandages, the possible use of vacuum-assisted closure bandages, and other special needs. Preoperative plans allow all personnel involved to take part in the surgical activity more properly and efficiently. Finally, the preoperative plan should specify antibiotic coverage. Typically, a good broad-spectrum antibiotic, such as a cephalosporin, is chosen. In closed and uncomplicated fractures, the first dose should be administered in the preoperative holding area, and the antibiotic should be continued for about 24 hours postoperatively. In open fractures or grossly contaminated wounds, more aggressive antibiotic coverage may be necessary, and use of an aminoglycoside or a β-lactam-containing drug should be considered. In patients with true penicillin allergies with cephalosporin crossover, clindamycin is the usual recommended alternative.

Prior to actually entering the operating room, the lead surgeon should identify the patient and mark the appropriate extremity in the vicinity of the surgical incision with an indelible pen. This helps avoid the possibility of a wrong site surgery. It is best done with the patient’s assistance, and before any preoperative sedation is administered.

PROCEDURE

Patient Positioning/Room Setup

Forearm fractures ordinarily can be addressed with the patient in the supine position. A sturdy arm table extending from the regular operating room table is of great benefit in supporting the patient’s arm during the procedure. The arm table allows the surgeon(s) and assistant(s) to be comfortably seated for the duration of the procedure. Prior to starting the surgery, it is useful to ensure that radiographic imaging devices can be moved easily into and out of the surgical field. Waiting to bring the C-arm or similar imaging device into optimum position until it is actually needed is inefficient and can lead to contamination of the surgical field (Figure 3).

ORIF of the forearm is best performed under tourniquet control. Checking that the tourniquet is accurately set and in proper working order before the start of surgery is strongly advised. Similarly, making sure that the internal fixation set is complete is recommended. Missing plates and/or inadequate numbers or varieties of screws should be determined before the start of surgery. A missing plate or an insufficient number of appropriate-length screws can compromise the quality and reliability of the surgical procedure, as well as the results.

Once all preparations have been completed the actual surgery is ready to start. This should begin with all parties introducing themselves and indicating their respective roles. This includes surgeon, assistant(s), scrub personnel, anesthesia personnel, circulating and other support nurse(s), radiology technicians and C-arm operator(s), students, manufacturer’s representatives, and any other people in attendance. The surgeon must then call for a “time out” in all operating room activity while he or she verifies the identity of the patient, the location of the intended surgery, the nature of the planned procedure, the equipment needed, and critical points along the course of the procedure. It is also a good time to confirm that antibiotics have been administered and deep vein thrombosis prophylaxis, if indicated, has been initiated, and to give nursing personnel an idea of what suture and dressing materials are being considered. This latter step can save valuable time at the end of the procedure.

FIGURE 3 Photographs show the room setup and patient positioning for open reduction and internal fixation of a both-bone forearm fracture. A, The room setup, with C-arm, back table, and instruments prepared. B, The patient is positioned supine on the operating table with the injured arm supported on an arm table.

Surgical Technique

The affected extremity is exsanguinated with an Esmarch wrap, and the tourniquet is inflated to approximately 100 to 125 mm Hg above systolic pressure. The particular incisions and surgical approaches used are usually determined by the fracture location and pattern. For most forearm fractures, an extensile approach, such as the volar approach of Henry¹⁶ (Figure 4), is sufficient for the radius; for the ulna, an ulnar midline approach usually is preferred.

In general, the bone with the more simple fracture pattern is addressed first. This fracture will be somewhat easier to reduce and fix, and once it is stabilized with a plate and screws, fixation of the second fracture can be a little less onerous. In fractures that are very unstable because of extensive associated soft-tissue disruption, however, fixing the ulna first can be a major challenge because of the need to hold the forearm in a suspended position as the plate and screws are being applied. This can make an already challenging task more trying and frustrating. Under these circumstances, fixing the radius first, even when it is the more severe fracture pattern, can simplify the surgical task.

Approach for Radial Fixation

The volar approach of Henry¹⁶ is an extensile incision that facilitates easy access to the fractured radius and permits the initial length of the incision to be increased if necessary to gain exposure of the entire length of the radius. The initial incision is made anywhere along a line extending from the biceps tuberosity proximally to the prominence of the scaphoid tuberosity distally; the volar-ulnar border of the brachioradialis muscle is the most consistent landmark. The actual placement of the initial incision will be determined by the location of the fracture. Distally, the interval is generally between the brachioradialis muscle and the flexor carpi radialis (FCR) muscle (Figure 4, C and D). More proximally, the interval is between the brachioradialis muscle and the flexor digitorum superficialis muscle. Distally, as dissection is taken more deeply, the pronator quadratus muscle will be encountered, covering the broad, flat surface of the radius. More proximally, deeper dissection will reveal the pronator teres muscle (Figure 5) and the near contiguous supinator muscle. In extreme circumstances, dissection can be carried even farther, between the brachioradialis muscle and the brachialis muscle, completely exposing the superficial radial nerve in the process.

In the midforearm, the radial nerve will be encountered along the deep surface of the brachioradialis muscle (Figure 6). The nerve usually is found under the epimysium covering the muscle and should be specifically identified to avoid injury. More distally, the nerve gradually begins to emerge from under the brachioradialis muscle along its more volar margin. Similarly, several small perforating arterial branches from the radial artery that supply the brachioradialis usually are encountered at the junction of the middle and distal thirds of the radius. Careful recognition of these branches and preemptive cauterization or ligation when identified can save much valuable time and avoid potentially dangerous bleeding later.

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