8 Fractures of the Radial Head (21-A2.2, 21-B2.1, 21-B2.2, and 21-B2.3)

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8.3 Guides to Treatment

8 Fractures of the Radial Head

(21-A2.2, 21-B2.1, 21-B2.2, and 21-B2.3)

J. Schatzker

8.1 Introduction

The goal of treatment of fractures of the radial head is the preservation of elbow flexion and extension, of forearm supination and pronation, and in complex fracture dislocations of the elbow, the preservation of the stability of the elbow joint.

8.2 Mechanism of Injury

The vast majority of fractures of the radial head are sustained in a fall onto the outstretched hand. The force of the fall is transmitted through the radius to the elbow, where the head of the radius is driven against the capitellum. Thus, the damage may not only be to the radial head, but also to the capitel- lum. Occasionally, the radial head may fracture as a result of a valgus force to the elbow, when the injury may also become complicated by a fracture of the olecranon. In these complex injuries, it should be remembered that the medial collateral ligament of the elbow is frequently torn. The rupture of the col- lateral ligament on one side and the fracture of the radial head on the other render the elbow joint com- pletely unstable.

8.3 Guides to Treatment

Considerable confusion continues to exist on how best to treat fractures of the radial head. Much of the confusion has been caused by an attempt to treat the radiograph rather than the patient. Some have advocated excision of the radial head if the fracture

involved more than one-ninth of the circumference, while others have asserted with equal dogmatism that it should be one-sixth and some that it should be one- third. Some surgeons, guided by the experience that not only is the fragment always bigger than suggested by the radiograph but also that the damage to the radial head, in the form of comminution and articu- lar depression, is always greater than anticipated, have gone so far as to advocate the following: “When in doubt, operate” and excise (Keon-Cohen 1966).

Since the goal of treatment is the preservation of function, the treatment must be directed to preserv- ing motion at the elbow. Permanent loss of motion occurs either as a result of a bony block caused by a displaced piece or pieces of bone or by capsular and pericapsular scarring. Early movement is the only measure available to prevent capsular and pericap- sular scarring. Loss of movement due to a bony block can be corrected only by removal of the block. Thus, we feel that once the diagnosis of a displaced fracture of the radial head has been established radiologically, the surgeon must establish beyond doubt whether a bony block to movement exists or not.

An intra-articular fracture is invariably associated with varying degrees of hemarthrosis. The distended joint is painful and the patient is reluctant to attempt any active movement or permit any passive manipu- lation. Considerable relief of pain is gained by aspira- tion of the hemarthrosis and infiltration of the joint with a local anesthetic, such as 2% Xylocaine (lido- caine). The advantage of local anesthesia is that once the joint becomes relatively painless, it is possible to determine whether or not there is a bony block to motion. If no block to motion is present, then early active motion is to be encouraged. We have treated displaced fractures in this fashion, regardless of their radiological appearance. The results have been grati- fying, and despite incongruity of the articulation between the radial head and the capitellum, post- traumatic osteoarthritis has not developed. Loose intra-articular fragments and fractures with a block to motion under anesthesia, however, constitute an indication for surgery.

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8.4 Guides to Treatment

Excision of the radial head is not advisable. Stud- ies by Pennal and Barrington (T. Barrington, personal communication) have demonstrated that in those who make heavy demands on their wrist and elbow, such as manual workers, excision of the radial head is followed by proximal migration of the radius. This leads to inferior radioulnar joint disturbance with pain and weakness of the wrist.

Radiographs of a fractured radial head are difficult to interpret and are often misleading. An accurate assessment of the fracture is only possible at the time of surgery. It is then possible to determine whether open reduction and internal fixation of the radial head are feasible or whether the radial head should be excised. We do not believe in partial excision of the head, because the results have been uniformly less satisfactory than after excision of the whole head.

8.4 Surgical Treatment

We consider the following to be indications for sur- gery:

– Major loose intra-articular fragments

Displaced fractures which under anesthesia can be demonstrated to constitute a block to motion – Displaced fractures of the radial head associated

with fractures of the olecranon or with rupture of the ulnar collateral ligament, or with both

– Fractures of the radial head associated with an injury to the distal radio-ulnar joint and inter- osseous membrane rendering the radius axially unstable

Although excision of the radial head might be con- templated as definitive treatment for a comminuted fracture if such a fracture is in isolation, it cannot be considered an option if the fracture of the radial head is associated with rupture of the ulnar collateral ligament and instability of the elbow joint. Although the ulnar collateral ligament is the primary stabilizer and the radial head the secondary stabilizer of the elbow, a repair of the ulnar collateral ligament will not render the elbow stable if the radial head is miss- ing. Therefore, under these circumstances, either an open reduction and internal fixation of the radial head fracture can be performed, or the radial head can be excised and replaced with a prosthesis, which will act as a spacer and will stabilize the joint. We feel that preservation of the radial head is preferable to

excision. The decision regarding whether an open reduction and fixation is feasible must be based, as in all other fractures, on the personality of the fracture.

A biological spacer is always better than a prosthe- sis. It is better to reduce and fix a radial head, even if not perfectly, and have it act as a spacer. If pain is the sequela of the less than perfect reduction, a late excision can be carried out. The ligaments will have healed and instability will have been prevented.

8.4.1

Classification

In evaluating radial head fractures, we recognize three types:

– Type I: split-wedge fracture. The fracture consists of a simple split-wedge fragment which may be displaced or undisplaced (Fig. 8.1a).

– Type II: impaction fracture. In this fracture pat-

tern, part of the head and neck remain intact.

The portion involved in the fracture is tilted and impacted, with the amount of comminution being variable (Fig. 8.1b).

– Type III: severely comminuted fracture. The hall-

mark of this fracture is that no portion of the head or neck remains in continuity and that the com- minution is very severe (Fig. 8.1c).

The Comprehensive Classification of Fractures of Long Bones (Müller et al. 1990) is not very helpful in distinguishing the different fracture patterns. The isolated fracture of the radial neck is a type A and therefore would be coded as 21-A2.2 and 21-A2.3.

The split wedge type I and the impaction type II and the multifragmentary type III are all partial articular fractures and are coded as B, which does not indi- cate the severity of the articular head fracture. The split wedge type I would be 21-B2.1. The impaction type II would be either 21-B2.2 or 21-B2.3 depending on the degree of fragmentation and depression. The severely comminuted fracture type III could be either 21-B2.2 or more likely 21-B2.3. Thus we feel that for coding purposes and for documentation the com- prehensive classification is useful, but not for daily practice, where we feel the simple terms split wedge, impaction, and multifragmentary are more useful.

Articular fractures of the radial head associated with olecranon fractures are classified as type C.

Severely comminuted fractures are irrecon- structible. If a block to motion exists, the surgeon must decide between simple excision or excision and

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8.4 Surgical Treatment

prosthetic replacement. If the fracture of the head is part of a fracture dislocation of the elbow, one must either reconstruct or replace the head with a prosthe- sis. In the other two fracture patterns, if there is an indication for surgery because of a block to motion, the decision between excision on the one hand and reduction and fixation on the other must be made on the basis of the personality of the injury. As already stated, in younger patients we prefer reduction and fixation to excision.

8.4.2

Positioning and Draping the Patient

The patient is placed in a supine position. The limb is prepared from the axilla to the wrist and is draped free to permit pronation and supination of the fore- arm. The procedure is performed under tourniquet control.

8.4.3

Surgical Exposure

The approach is lateral. The incision begins at the lateral epicondyle and is extended just distal to the radial head. The common extensor muscle is split along the line of its fibers in line with the skin inci- sion. Care must be taken to stay posterior to the radial nerve, which crosses just in front to enter the sub- stance of the supinator muscle, approximately 2 cm distal to the radial head. The incision must therefore not extend distally below the annular ligament. Fur-

thermore, if damage to the nerve is to be avoided, retraction must be gentle; if difficulty in visualiza- tion of the joint is encountered, it is best to release the lateral collateral ligament with an attached piece of the lateral epicondyle. At the close of the pro- cedure the continuity of the collateral ligament is reestablished by screwing the osteotomized piece of bone back into place. The capsule is opened later- ally and the radial head is visualized. Pronation and supination permit different portions of the head to be brought into direct vision. Another approach is the dorsal one. Exposure of the radial head and neck is achieved by detachment of the anconeus muscle from the ulna and the lateral epicondyle. This gives a better exposure of the medial portion of the head and of the radioulnar articulation, but does not ease manipulation of fragments or internal fixation. For this reason we prefer the former approach.

8.4.4

Techniques of Reduction and Internal Fixation

8.4.4.1

Comminuted Fractures

The type III severely comminuted fracture, in which there is no continuity of the head and neck, cannot be reduced and fixed. The head is therefore excised.

The decision as to whether a prosthetic replacement should be carried out must be made in each individ- ual case. We feel that the only absolute indication for prosthetic replacement of the radial head is a disloca- tion of the elbow with rupture of the medial collateral ligament, with or without an associated fracture of

Fig. 8.1. a A split-wedge fracture. In this fracture, a part of the head remains intact. Fixation is simple with two 2.7-mm cortical screws used here as lag screws. The heads are recessed below the level of the articular cartilage. b An impaction fracture. Here again, a part of the head remains intact. The fracture fragments may be single, but more often there is some comminution. The fragments are tilted and the bone beneath them crushed or impacted. There may also be a transverse fracture across the neck.

c A severely comminuted fracture. There are many fracture fragments, usually with significant displacement. Please note that this is a complete articular fracture in which all the fragments have lost connection with the neck.

a b c

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the olecranon. The prosthesis is required to act as a spacer and prevent valgus displacement and possible redislocation, even if a direct repair of the medial collateral ligament is carried out. The excised and provisionally reconstructed head is a useful template for the prosthesis to be used. The newly available metal modular prostheses make the correct choice of length and head size possible.

8.4.4.2

Split-Wedge Fractures

Type I split-wedge fractures are easily reduced and fixed with a lag screw. We have found the mini or small cortical screws best for fixation of these frac- tures. If the screw is inserted through the articular cartilage of the head, it should be recessed below the articular surface (Fig. 8.2). The small Herbert screws are also very useful for fixation in these situations.

8.4.4.3

Impaction Fractures

Type II impaction fractures are the most common type. They fall in complexity between type I and type III. The fragments are tilted, depressed, and impacted.

Whether reduction and fixation is possible depends

Fig. 8.2. The fixation of a wedge fracture is simple. Two 2.7-mm cortical screws are used as lag screws. The heads of the screws are recessed below the level of the articular cartilage

Fig. 8.3. a In an impaction fracture, if a portion of the head remains intact, fixation is relatively simple. The fragments are lagged to the intact portion of the head. Again, 2.7-mm screws are used for fixation. b–g A preoperative radiograph, 4 months after surgery

a

f g e

d

b c

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on the degree of comminution. If only one or two fragments are present, reduction is usually possible.

The fragments should be elevated, provisionally fixed with a Kirschner wire, and then lagged to the remain- ing portion of the head and neck with one or two small or mini screws as in type I. Since the injury is usually the result of a valgus force with the forearm in supination, the medial portion of the head and neck is usually intact (Figs. 8.3–8.5). Occasionally, the cen- tral comminution may be such that compression with a lag screw would narrow and distort the head. In such cases, a thread should be cut in both fragments, which will prevent the screw from acting as a lag screw. All fragments should be drilled with the 2.0- mm drill bit and tapped with the 2.7-mm tap. We have indicated the use of the 2.7-mm cortex screws. If the fragments are smaller, the surgeon should resort to using the 2.0-mm or even the 1.5-mm cortex screws, as indicated. If the head fracture is associated with fracture of the neck, fixation of the neck fracture should be carried out with the aid of either the T- or L-plate. Care must be taken however in positioning the plate so as not to interfere with pronation and supination.

Fig. 8.4. If there is a transverse fracture of the neck, fixation of the head must be supplemented with a plate. The mini T plate must be carefully contoured and positioned in such a way as not to interfere with the radioulnar articulation in pronation or supination

8.4.5

Postoperative Care

Suction drainage is used for the first 24 h. Stable fixation eliminates bone pain and makes it safe and possible to begin early active flexion – extension and pronation – supination exercises. We immobilize the elbow at 90° in a padded posterior splint. On the second or third day, the dressings are removed and, if no complications exist, active mobilization exercises are started. We discourage the use of a sling because it maintains the elbow in flexion. Pronation, supina- tion, and flexion usually return almost to normal without much difficulty. The last 10°–15° of extension are very difficult to regain, no matter what form of treatment is used. We have concluded from a trial that CPM machines are not useful in fractures of the radial head.

References

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

Müller ME, Nazarian S, Koch P, Schatzker J (1990) The comprehensive classification of fractures of long bones. Springer, Berlin Heidelberg New York

Fig. 8.5a–d. Small, free, comminuted fragments can be reduced and fixed with lag screws. Because of their small size, they revascularize without collapse. a,b Note the displacement of the fragment. It blocked flexion of the elbow. c,d Six months after reduction and fixation

a b c d