Fractures of the olecranon occur in response to direct impact to the posterior surface of the elbow, falls onto the flexed elbow, and other falls on the upper extremity that indirectly load the joint. Powerful firing of the triceps muscle can result in an avulsion fracture of the tip of the olecranon process. In general, the distal humerus remains articulated with the intact distal ulnar fragment, while the olecranon fracture fragment is displaced posteriorly and superiorly.
Almost all fractures of the olecranon process are intraarticular. Fractures of the olecranon are thus associated with a bloody effusion in the elbow joint. There may be pain and swelling over the olecranon, and the fracture line may be palpable on the subcutaneous border of the ulna. Most importantly, most patients with an olecranon fracture, as the result of a discontinuity in the triceps mechanism, will have lost the ability to extend the forearm against gravity.
Colton (3) classified olecranon fractures into two major groups: nondis-placed fractures and displaced fractures. A nondisplaced fracture is defined as having less than 2 mm of separation, with no increase in displacement with flexion of the elbow to 90 degrees, and the patient being able to extend the elbow against gravity. Displaced fractures were further subdivided into avulsion fractures, oblique and transverse fractures, comminuted fractures, and those associated with a fracture/dislocation of the elbow. Avulsion fractures result in the separation of a small proximal segment of the olecranon process from the rest of the ulna. With a transverse injury, the fracture line runs obliquely, starting near the deepest portion of the olecranon fossa and emerging on the subcutaneous crest of the proximal part of the ulna. This fracture may either be simple or have more than one fragment. Comminuted fractures have multiple fragments and usually result from direct trauma to the posterior aspect of the elbow. There may be articular impaction and other associated injuries at the elbow. In fracture/ dislocations, the olecranon fracture is usually at the distal end and exits near the coronoid process, so that the elbow is unstable as well. This is usually associated with an anterior dislocation of the radius and ulna.
Nondisplaced fractures can be effectively treated by immobilization. Splinting, casting, or bracing of the elbow in 90 degrees of flexion usually results in a satisfactory result. Radiographs must be obtained 7 to 10 days into this treatment to make sure that no displacement has occurred. If displacement occurs, there is still adequate time before healing to effect a successful reconstruction before healing becomes too advanced. Protected range-of-motion exercises can be started at 3 to 4 weeks. Care should be taken to avoid forcible flexion past 90 degrees or resistive exercises until the fracture shows signs of radiographic union.
Displaced fractures of the olecranon are treated operatively. The goals of treatment are to maintain active elbow extension, avoid incongruity of the joint surface, restore elbow stability, and maintain range of motion. Fixation should be achieved with a method that will allow range of motion of the fracture as soon as possible.
Fractures of the olecranon are approached directly from the posterior aspect of the arm. The patient can thus be positioned supine with the arm draped across a stack of towels on the chest, in the lateral position with the arm draped over an arm holder or stack of blankets, or in the prone position using a humeral arm holder. The supine position requires an assistant to constantly hold the arm, while the lateral and prone positions allow the surgeon to operate independently. In multiply injured patients and those with spine injuries, the supine position may be helpful in avoiding further patient compromise.
Avulsion fractures can be intra- or extraarticular. They occur commonly in the elderly population but still require operative treatment in order to restore elbow function. The mainstay of treatment is direct repair of the triceps and proximal fragment to the remaining ulna with nonabsorbable suture through drill holes. The fracture is exposed directly via a posterior approach. A large (#2 or #5) suture is woven through the triceps tendon and then passed through drill holes created in the proximal ulna. Care must be taken to tension the suture with the arm in full extension to have the tightest repair. This method may be supplemented by a tension-band wire (as detailed below) to neutralize the pull of the triceps.
Transverse and short oblique are the most common types of fracture; the tension-band wire technique is the workhorse method for stabilizing these injuries (4). In this method, after fracture reduction, a wire loop is placed around the proximal fragment and through the distal fragment, dorsal to the midaxis of the ulna. In this position, the tensile deforming force of the triceps is neutralized and converted into a compressive force at the fracture site. Improved alignment and greater stability can be provided by introducing two parallel K wires across the fracture site before applying the tension band. This method provides immediate stability and allows early active range of motion.
In the tension-band technique, the fracture site is approached directly from the posterior aspect of the forearm. The fracture site is debrided of clot and soft tissue and reduced anatomically. During reduction, any depressed areas of the joint are elevated, and the fracture is bone-grafted if needed. Two parallel K wires are then placed from dorsal and proximal on the ulna to anterior and distal just across the fracture site. The wires are made long enough to just catch the anterior cortex of the ulna.
Proper placement of the wire loop is essential to the success of this technique. A hole is drilled transversely in the ulna, dorsal to the midaxis of the shaft and distal to the fracture line. As a rule, the distance between the ulnar drill hole and the fracture should be at least equal to the distance from the fracture to the tip of the olecranon. This wire loop is passed deep to the triceps tendon and held in place by the two K wires, bent into a figure-of-eight fashion, and passed through the drill hole. With the forearm in extension, the loop is then tightened and the fracture line compressed. The K wires are then bent over the end of the tension wire and impacted into the proximal segment.
Alternatively, the fracture can initially be stabilized with two parallel small fragment screws or a partially threaded 6.5-mm cancellous screw placed down the shaft from the proximal piece. The wire loop is then placed to neutralize these constructs. The use of screws may offset some of the reported difficulties of the K wires backing out, causing discomfort and limited range of motion.
Some have advocated the use of a heavy nonabsorbable suture in place of wire to avoid the problem of wire breakage and pain on the subcutaneous border of the ulna. Even with these technique modifications, many patients will have hardware related issues that will require metal removal after fracture union.
Comminuted fractures (Fig. 1) and fractures involving the coronoid process or those that extend down the shaft of the ulna are not amenable to tension-band wiring. These fractures require interfragmentary reduction and neutralization with a plate in order to restore the anatomy and elbow stability. This plate, placed on the dorsal or dorsolateral surface of the ulna, functions as a neutralization device and a tension band. A 3.5-mm compression plate, one-third tubular plate, or pelvic reconstruction plate can be contoured to extend from the tip of the olecranon, across the fracture, and down the shaft of the ulna as needed. The 3.5mm compression plate is bulky and can be more difficult to contour than the pelvic plate. A one-third tubular plate has a low profile but may not be strong enough to resist bending forces, especially in fractures that have no inherent stability from the bony reduction. Bone graft may be added to support a depressed articular segment, and lag screws can be placed from outside or through the plate to provide optimal fixation.
In highly comminuted fractures, particularly in the elderly, some have advocated olecranon excision and triceps reattachment as an alternative method of treatment. Poor bone quality or a highly comminuted fracture may make the fracture not amenable to reconstruction. The advantages of excision are that it is easy and rapid, eliminates the possibility of delayed union, nonunion, or posttraumatic arthritis; and allows early range of motion. The disadvantage of excision is said to be triceps weakness, elbow instability, and loss of motion. Rettig (6) found elbow motion to be equal after internal fixation or excision. Gartsman (7) found range of motion, elbow stability, and strength to be equal in patients who underwent open reduction compared to those who underwent excision. However, Gartsman's technique was not uniform and the elbow was immobilized in the postoperative period, delaying functional aftercare. Excision of the proximal ulna, though an option in difficult cases, cannot be advocated as the primary surgical treatment for this fracture.
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