7 Fractures of the Olecranon (12-B1)

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7.1 Introduction

7 Fractures of the Olecranon (12-B1)

J. Schatzker

7.1 Introduction

A displaced fracture of the olecranon represents a disruption of the triceps mechanism and, as a con- sequence, the loss of active extension of the elbow.

The necessity for surgical repair has been appreciated ever since Lord Lister attempted an open reduction and suture of the olecranon (Keon-Cohen 1966). The methods of surgical repair have varied. Some authors have advocated excision of the fragment or frag- ments with repair of the triceps aponeurosis (Keon- Cohen 1966). Others have advocated the fixation of the fragment with intramedullary nails, screws, or plates (Weseley et al. 1976). As indications became more clearly defined, resection of the proximal frag- ment and reattachment of the triceps tendon to the distal fragment was reserved for elderly patients in whom the fracture was proximal to the middle of the trochlear notch (Rowe 1965). Younger patients were subjected to an open reduction and an attempt was made to stabilize the fragments, either with a through-and-through loop of wire (Fig. 7.1) or with a long intramedullary lag screw (Fig. 7.2).

If the olecranon fragment was small, excision usually resulted in a stable elbow with a satisfactory range of motion. If the fragment was large, it became

increasingly more difficult to preserve an adequate cuff of the triceps aponeurosis to effect a repair. If the fragment involved more than 50% of the articular surface, instability of the elbow followed resection.

Instability was a serious problem because it com- promised function, and therefore excision was aban- doned as a form of treatment for any but the smallest of fragments.

The methods of internal fixation with the wire loop, intramedullary Rush rod, or an intramedullary lag screw did not provide sufficient stability to allow early motion. The joint had to be immobilized until union occurred. Despite plaster of Paris immobili- zation, the triceps pull was frequently sufficient to cause displacement (Fig. 7.2). Typically, the fracture gaped dorsally, and frequently some separation of the fragments occurred, which led to gaps in the articu- lar surface and to joint incongruity with consequent compromise of function.

The duration of immobilization and the associated joint disorganization frequently led to varying losses in the range of flexion and extension. The dorsal gaping with displacement of the proximal fragment hindered full extension. Therefore, the loss of extension was often more severe than the loss of flexion. Because the elbow is not a weight-bearing joint and does not transmit such great forces as the knee joint, incongruity does not result rapidly in post-traumatic osteoarthritis. However, if the

Fig. 7.1a,b. A wire loop inserted through the substance of the olecranon (a) is unable to resist the pull of the triceps and brachial muscles against the intact troch- lea (b). Gaping of the fracture with varying degrees of displacement, despite protec- tion in a cast, is the usual outcome

a b

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7.1 Introduction

patient is called upon to perform heavy work requir- ing elbow flexion and extension against resistance, then progression of the osteoarthritis and an increase in pain and disability are to be expected.

In 1965, the AO group published the Technique

of Internal Fixation of Fractures (Müller et al. 1965),

which introduced tension band wiring as the most effective method of internal fixation of olecranon fractures. Their experiments showed tension band wiring to be six times stronger than any other fixation technique. By using this technique, it was therefore possible to forego the application of a plaster fixation and to begin active movement soon after surgery. At 4–6 weeks, the olecranon fractures were usually suf- ficiently healed to allow the patient full function. The rate of malunion or nonunion was extremely low, as was the degree of residual disability.

7.2 Methods of Evaluation and Guides to Treatment

The indication for surgery is displacement, which represents a disruption of the triceps mechanism and loss of active extension of the elbow. If the fracture is undisplaced, the surgeon must determine whether the triceps aponeurosis is intact or not. With an intact triceps aponeurosis, a patient is able to extend the elbow against gravity without causing any displace- ment of the fragments. Such a fracture is stable, will not displace under the influence of physiological forces, and requires only symptomatic treatment. If any doubt exists as to the continuity of the triceps aponeurosis, the elbow should be examined with the aid of an X-ray image intensifier. Any degree of displacement on full flexion signifies damage to the

triceps aponeurosis and suggests the need for either immobilization in extension or surgery.

The diagnosis is simple. Typically, the patient gives a history of having fallen and of not being able to use the elbow. The olecranon is very painful, swollen, and bruised. The exact diagnosis is established on an appropriate anteroposterior and lateral radiograph (Fig. 7.3). The anteroposterior view is more useful for an overall examination of the elbow to exclude other injuries, but the olecranon itself is obscured in this view. It is the lateral projection that gives a clear view of the olecranon. If there is any doubt as to the degree of comminution or articular surface depression, lat- eral tomograms or CT should be requested in order to obtain an accurate definition of the fracture.

7.3 Classification

7.3.1

Intra-articular Fractures

7.3.1.1

Transverse (21–B1.1)

This simple articular fracture occurs at the deepest point of the trochlear notch (Fig. 7.4). It is an avul- sion fracture and results from a sudden pull of both the triceps and brachialis muscles. It may also result from a direct fall on the olecranon itself, although that usually results in some degree of joint depression in association with the fracture.

Complex fractures that result from a direct force, such as a fall, frequently have comminution and depression of the articular surface (Fig. 7.5).

Fig. 7.2. A Rush rod or an intramedullary screw is also unable to resist the pull of the triceps and brachial muscles. Note the displacement of the olecranon

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7.3 Classification 7.3.1.2

Oblique (21–B1.1)

An oblique fracture usually results from a hyperex- tension injury of the elbow. It begins at the midpoint of the trochlear notch and runs distally (Fig. 7.6).

7.3.1.3

Comminuted Fractures and Associated Injuries

Comminuted fractures and associated injuries are the result of a high-velocity direct injury to the elbow,

such as might result from a considerable fall directly on the elbow or in high-velocity motor vehicle acci- dents. The fracture lines are variable, but certain fea- tures must be distinguished.

1. Fractures of the coronoid process. Small fractures of the coronoid process itself are unimportant if the elbow is other wise stable. If the fragment is large, it represents the distal articular surface of the trochlear notch and cannot be neglected, because of resultant instability of the elbow in extension (Fig. 7.7).

Fig. 7.3. A fracture of the olecranon with displacement. Note in this example the associated disruption of the elbow joint with subluxation

Fig. 7.4. A transverse fracture of the olecranon

Fig. 7.5. A complex transverse fracture. Note the impaction of the central portion of the articular surface. This fragment is frequently diffi cult to reduce and, because of its position, diffi cult to fi x. Once the fragment is disimpacted, a hole is left which may occasionally have to be bone-grafted

Fig. 7.6. An oblique frac- ture of the olecranon – the result of hyperextension

Fig. 7.7. a Severe comminution. Note also the fracture of the coronoid process. Such a comminuted fracture requires a neutralization plate, which can also act as a tension band.

b A comminuted fracture of the olecranon ﬁ xed with a plate, Kirschner wires, and a tension band wire

a

b

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7.3 Classification

2. Distal extent of the fracture. If the fracture extends distally past the midpoint of the trochlear notch (Fig. 7.8), it is no longer merely a disruption of the triceps mechanism. It compromises the stability of the elbow in withstanding varus or valgus forces and tends to shorten, compromising not only the elbow but also forearm pronation and supina- tion.

3. Fracture or dislocation of the radial head. An associated fracture of the radial head comprises a dislocation of the elbow and is usually associated with a disruption of the medial collateral ligament (Fig. 7.9). It implies ligamentous instability of the elbow that may not be corrected by reduction of the olecranon fracture and repair of the ligament.

The radial head must be reduced and fixed or replaced by a prosthesis.

7.3.2

Extra-articular Fractures

Avulsion fractures of a small part of the tip of the olecranon with the attached triceps tendon result in the same loss of function as a transverse fracture of the olecranon. The mechanism of injury is probably the same.

7.4 Surgical Treatment

7.4.1

Positioning the Patient

The patient should be positioned either prone or lying on the uninjured side. This position automati- cally exposes the posterior aspect of the elbow and allows a direct unobstructed surgical approach. The elbow must be free to be flexed or extended. The force of gravity maintains traction on the forearm and keeps it in the correct position throughout sur- gery. This obviates the need for an assistant, who would otherwise be required to hold the forearm of a supine patient in a position indicated by the sur- geon. With the patient lying on the uninjured side or prone, the position of the forearm is adjusted simply by placing a rolled-up sheet under the forearm as required (see p.106).

7.4.2 Draping

The surgical scrub should extend from the level of the tourniquet, which is applied as high as possible on the arm, to the wrist. The extremity must be draped free to allow for unobstructed flexion and extension of the elbow.

7.4.3 Tourniquet

We prefer to use a tourniquet when dealing with intra-articular fractures. It reduces bleeding, allows better visualization of the intra-articular compo- nents, and leads to a more accurate reconstruction of the joint.

Fig. 7.8. A fracture of the olecranon which is distal to the midpoint of the trochlear notch. If not comminuted, such an oblique fracture should be fi rst stabilized with one or two lag screws. Kirschner wires are not enough for lateral support. To overcome varus/valgus instability and resistance to torque, these distal fractures, even if fi xed with lag screws, should be fi xed with a plate. Semitubular plates are not strong enough to resist torsional forces. The 3.5-mm dynamic compression (DC) plates should be used to stabilize these fractures

Fig. 7.9. A fracture of the olecranon associated with a fracture of the radial head (21–B3.3). These fractures are frequently associated with a rupture of the medial collateral ligament of the elbow. The elbow remains unstable until the olecranon fracture is ﬁ xed, the medial collateral ligament repaired, and the radial head either reduced and ﬁ xed with screws or replaced with a prosthesis. Resection of the radial head will result in valgus subluxation of the elbow

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7.4 Surgical Treatment

7.4.4

Surgical Exposure

The incision is begun posteriorly in the middle of the supracondylar area of the humerus and is extended distally on the medial side of the olecra- non to a point three or four fingerbreadths distal to the fracture. The incision should not cross the point of the olecranon, as it might lead to a pain- ful scar. We prefer to use an incision on the medial side of the olecranon for two reasons. First, it is cosmetically more pleasing because it is less appar- ent. Second, we feel that the ulnar nerve should be identified and protected during the surgical exposure and reduction (Fig. 7.10). If the incision is radial, it is more difficult to expose the ulnar nerve and follow it distally without undermining a considerable flap. The olecranon bursa is incised and no effort is made to protect it. If the fracture is exposed with the elbow flexed, it usually gapes, which facilitates the identification of the fracture lines without undue stripping of the flexor carpi ulnaris muscle from the medial side of the olecra- non. The fracture and the articular surface should be exposed through the fracture by increasing the deformity of the proximal fragment. If the fracture is comminuted, but particularly if the joint surface is depressed, it is necessary to visualize the articular surface to check the accuracy of the reduction. This cannot be done safely from the medial side because of the ulnar nerve and because of the attachment of the deltoid ligament. Good exposure of the joint can be obtained from the lateral side by detaching a portion of the anconeus muscle from the radial side of the ulna (Fig. 7.10).

7.4.5

Techniques of Reduction and Internal Fixation

7.4.5.1

Transverse Fractures

The reduction of the olecranon fracture is easiest with the elbow in extension, because this relaxes the pull of the triceps muscle. Once carefully reduced, the fracture should be held reduced with a pointed reduction clamp. Two Kirschner wires are then inserted parallel to one another and in the direc- tion of the long axis of the ulna. A common error is to cross them. This holds the fracture apart and prevents compression. Some surgeons have been rec-

ommending to angle them anteriorly and exit them through the anterior cortex near the coronoid pro- cess and to use wires with threaded ends in order to engage the anterior cortex and in this way prevent the backing out of wires. We are not in favor of the insertion of the wires into or through the anterior cortex. First, if inserted through the anterior cortex the wires may damage vital structures. If they are angled too far anteriorly, they may enter the joint.

Secondly, the backing out of wires is prevented by proper insertion of the tension band around the tri- ceps aponeurosis and not around the wires, which is a very common error. Correct insertion of the K- wires is greatly eased if the elbow is slightly flexed and if the cortex of the olecranon fragment is predrilled with a 2.0-mm drill bit. The Kirschner wires should be 1.6 mm in diameter. If they are any thicker, they are too difficult to bend. The bending over is necessary in order to drive the ends into the bone. This helps to maintain the wires in position and also makes them less palpable at the point of the elbow. The K-wires should be inserted with a power drill with the help of a telescoping wire guide. The surgeon should aim parallel to the subcutaneous border of the ulna. These wires are important because they are an internal splint that prevents rotation and lateral displacement.

The wire for the tension band is inserted through a 2.0-mm drill hole that is drilled distally, approxi-

Fig. 7.10. Surgical exposure of the olecranon. Note the isolated and protected ulnar nerve that dips into the tunnel of the ulnar fl exor muscle of the wrist next to the fracture. To visualize the joint, the fi bers of the ulnar fl exor muscle of the wrist and anconeus muscle must be refl ected

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7.4 Surgical Treatment

mately the same distance from the fracture as the tip of the olecranon. The drill hole must be deep to the subcutaneous cortex of the ulna. If it is too superfi- cial, the wire will cut out. The wire for the tension band should be 1.0–1.2 mm in diameter and should be made of stainless steel, which is sufficiently ductile to permit twisting.

The tension band wire must pass deep to the triceps tendon and be just proximal to the two Kirschner wires. We have found a gauge 14 or 16 needle a great help in passing the wire correctly deep to the triceps tendon. If the wire is passed only around the two Kirschner wires, there is a risk of the Kirschner wires backing out and perforating the skin.

B.G. Weber (ca. 1972, personal communication) suggested that before the figure-of-eight tension band is tightened, two loops should be made to allow simultaneous twisting and tightening of both limbs of the figure-of-eight, to ensure uniform com- pression on both sides of the fracture. The two loops are not absolutely essential as long as the surgeon ensures that the wire is straightened out and pulled very tight before it is placed under tension by twist- ing. Once tension is applied, the wire binds and will not slide in bone. If the wire is not pulled tight and straightened before it is tightened, it may straighten after the internal fixation is completed and thus lengthen, which loosens the tension band and leads to failure of the fixation. The tension band should be tightened in full extension to effect a slight over- reduction of the fracture. This over-reduction dis- appears when the elbow is flexed and the whole fracture’s surface comes in contact. As the tension band is tightened, a slight gap in the articular sur- face is created, and the only part of the bone under constant axial compression is the posterior cortex and some adjacent cancellous bone. This is the only part that heals by “primary bone healing.” The remainder of the fracture is subjected to changing degrees of compression, because the compression increases when the elbow is flexed and decreases when it is extended. This flux in the degree of com- pression was seen in an experimental investigation to result in the central and subchondral areas of the fracture healing by endochondral ossification. The articular defect heals by the formation of fibrocar- tilage (Schatzker 1971).

With tension band fixation, flexion of the elbow increases the axial compression. This is fortunate because it increases the stability of the reduction and fixation, while with lag screw fixation or loop cerclage wiring, flexion causes displacement because

of the unopposed pull of the triceps. Fractures of the olecranon fixed with a tension band wire should not be splinted in extension. It is necessary and impor- tant to begin early active flexion, since this actually increases compression and stability and helps the recovery of function. A further advantage of tension band fixation is that it can be employed successfully in osteoporotic bone, since its strength does not depend on the holding power of a screw in the bone.

Its strength is determined by the resistance of the bone to the cutting out of the wire where it traverses the ulnar cortex and by the resistance of the triceps tendon.

7.4.5.2

Transverse Fractures with Joint Depression

The transverse fracture with comminution and joint depression requires special attention (see Fig. 7.5).

The articular fragment that is depressed and driven into the underlying cancellous bone represents a sep- arate piece of bone with a disrupted blood supply.

If it is large and left unreduced, joint incongruity and instability result. Therefore, it must be elevated in a manner similar to that described for the tibial plateau (see Sect. 16.4.5). The resultant defect must be bone-grafted. The graft, together with the axial compression, will aid in preventing redisplacement.

Occasionally, it may also be possible to splint it in position with one of the two axial Kirschner wires.

At the end of the procedure, the Kirschner wires are bent and cut to length and the free ends are driven into the bone, which further increases the stability of the fixation and hinders the wires from backing out.

Care must be taken, however, that these ends are cut short. Otherwise they may enter the joint.

7.4.5.3

Oblique Fractures

The oblique fracture is reduced in the same way as a transverse fracture. The stability of the fixation can be greatly increased if a lag screw is inserted at right angles to the fracture line. The internal fixation then follows, as described previously, with the two Kirsch- ner wires and a tension band wire. In this instance, the tension band wire can be viewed as a neutraliza- tion wire, protecting the compression and fixation achieved with the lag screw. If the fixation with the lag screw is secure, the Kirschner wires can be omitted.

The tension band wire alone will be enough. If the fracture is distal, a plate should be used for fixation instead of a wire (see Fig. 7.7b).

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7.5 Postoperative Care 7.4.5.4

Comminuted Fractures

Comminuted fractures, the result of high-velocity injury, are frequently complex and may pose great dif- ficulties when reduction and fixation are attempted.

Reduction may be made easier if indirect reduction techniques are used. However, this must not be at the expense of an anatomical reduction of the articular surface. If the surgeon decides to use direct reduction techniques, then the reduction should commence dis- tally and proceed toward the joint. Thus, if there is an extension wedge fragment distal to the coronoid process, an attempt should be made to reduce it and fix it with a lag screw before proceeding with the reduction of the joint surface. The articular surface of the distal fragment must be clearly visualized. Fre- quently, this can only be achieved if the proximal and distal fragments are widely separated.

If there is an associated fracture of the coronoid, and if significant in size, it should be reduced first and held provisionally with small bone-holding for- ceps or a Kirschner wire while it is fixed with a lag screw passed up through the posterior cortex of the ulna. A cannulated screw is particularly useful in this situation. The reduction and fixation of this fragment is important if stability of the elbow in extension is to be restored. The remaining fragments are then reduced and fixed to each other by whatever means is most suitable. Once reduced, the olecranon is then splinted by the insertion of the two axial Kirschner wires.

If the fracture extends past the coronoid process, it can no longer be viewed as an isolated fracture of the olecranon subjected only to the pull of the triceps.

Once the fracture involves the whole trochlear notch of the ulna and extends distal to the coronoid pro- cess, it becomes subjected to considerable torque and valgus/varus stress, and the simple Kirschner wires and tension band fixation are no longer enough.

For such fractures, we like to combine the Kirschner wire and tension band fixation with a plate which is applied along the posterior cortex of the ulna and olecranon (see Fig. 7.1b). This plate protects the frac- ture from the varus/valgus and torsional stresses.

Occasionally, we resort to the use of a plate even if the fracture does not extend distal to the coronoid process, but is very comminuted so that no continu- ity exists in the posterior cortex. In such a case, as a tension band is tightened, the fragments tend to tele- scope, and the reduction might be lost and the joint become deformed. For such fractures, we use a plate, which buttresses the fragments and helps maintain

their relative position. We have found the small, 3.5- mm dynamic compression (DC) plate very useful for this purpose. A semitubular plate should not be used because it is too weak and tends to break. The small locked compression plates with their angular stability should prove very useful in these situations.

Because they are a very recent development, we have not had any personal experience with their use in these situations.

7.5 Postoperative Care

Suction drains are used to prevent hematoma forma- tion. These are removed after the first 24–36 h. The olecranon is held at 90° flexion on a padded poste- rior plaster splint for the first 2–3 days. The splint is then removed and the wound carefully inspected.

If no complications exist, the patient is encouraged to begin active flexion–extension exercises, which continue until a full range of movement is regained.

The fractures, if uncomplicated, are usually healed in 6 weeks. At this point, full unprotected use of the extremity can be resumed. Comminuted fractures, particularly those with extension into the diaphysis of the ulna and those with devitalized bone frag- ments, require a longer time for consolidation and must be protected from overload to prevent implant failure with malunion or nonunion. Initially, we were very enthusiastic about the use of continuous passive motion (CPM) machines in elbow fractures. Although we still feel that they have a major role to play in the complex reconstructive procedures, simpler olecra- non fractures do equally well with well-supervised early active mobilization.

References

Keon-Cohen BT (1966) Fractures of the elbow. J Bone Joint Surg 48A:1623–1639

Müller ME, Allgöwer M, Willenegger H (1965) Technique of internal fixation of fractures. Springer, Berlin Heidelberg New York

Rowe CR (1965) Management of fractures in elderly patients.

J Bone Joint Surg 47A:1043–1059

Schatzker J (1971) Fixation of olecranon fractures in dogs. J Bone Joint Surg 53B:158

Weseley MS, Barenfeld PA, Risenstein AL (1976) The use of the Zuelzer hook plate in fixation of olecranon fractures. J Bone Joint Surg 58A:859–862