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Radial Head Fracture : Management of Complications After Treatment


Unfortunately, a number of patients treated for a radial head fracture according to the principles described in previous chapters will not do well and may require further surgery. Management of these patients will be different depending on the nature of the complication developed, the presence of associated injuries or conditions, and the patient's anticipated demands and activity level. In this chapter, we will review a few aspects of the management of those patients presenting with failure after surgical treatment of a radial head fracture as it relates to the radial head; we will not include management of associated problems such as the Essex-Lopresti injury ( Chapter 41 ), management of the coronoid and ligaments in patients with persistent elbow instability ( Chapter 49 ), or management of the septic elbow ( Chapters 75 and 80 ) in this chapter.

Epidemiology

The rate of reoperation after attempted internal fixation has not been analyzed in detail ( Fig. 40.1 ). Reported rates of failure potentially leading to reoperation are primarily determined by the severity of the injury. For simple fractures (one or two fragments with some of the head still in continuity with the shaft), internal fixation is very reliable. As the complexity of the fracture increases, failures are more common. Some studies report failure rates of 30% to 50% when only the more complex fractures are included.

FIG 40.1, (A,B) Failed internal fixation with secondary fracture displacement.

There is more information published regarding the rate and risk factors for implant revision or removal after radial head arthroplasty. Duckworth et al. reported on 105 elbows followed for a minimum of 1 year after implantation of cemented monopolar prostheses. Of note, 86% of the implants were metallic but 14% were Silastic. Prosthesis removal (26) or revision (3) was performed in 28% of the elbows. The mean time from the time of the index arthroplasty was 7 months. The main risk factors for implant revision or removal were use of a Silastic implant and younger age. For metallic implants alone, revision or removal were associated with younger age and absence of associated comorbidities.

In a separate study, Ha et al. reviewed the clinical and radiographic features of 258 radial head prosthesis with a mean follow-up of one year. The authors identified radiographic loosening in 20%, capitellar osteoarthritis in 30%, prosthesis disassociation in 3%, and a rate of implant revision or removal for 24%. Half of the implants were removed or revised in the setting of removal of heterotopic ossification. There was a statistically significant association between radiographic changes and symptoms.

Van Riet et al. reported on the Mayo Clinic experience on 44 elbows that underwent removal of failed metallic radial head prostheses. Most reoperations were performed for painful loosening (31 elbows) ( Fig. 40.2 ). Revision was undertaken for stiffness in 18, instability in 9, and deep infection in 2 elbows. Overlengthening was identified in 11 elbows.

FIG 40.2, Loose radial head prosthesis.

Failure Mechanisms

Failed Radial Head Internal Fixation

The usual mechanisms of failure after attempted internal fixation of a radial head fracture are malunion, nonunion, and restricted forearm rotation secondary to excessive fibrosis or prominent hardware.

Radial Head Malunion

Radial head malunion after internal fixation of a radial head fracture can occur as a consequence of either nonanatomic reduction or secondary displacement. It can affect a segment of the radial head, the head-neck junction, or both. Head-neck malunion occurs in fractures with substantial comminution at that particular location, leading to healing with an abnormal tilt.

Radial head malunions can sometimes be well tolerated. However, they can also lead to pain or limited motion. In addition, they can contribute to instability: a distally displaced fragment, or excessive tilt of the whole radial head, can facilitate escape of the radial head underneath the capitellum as the elbow is moved into extension.

Radial head malunions should be carefully evaluated with plain radiographs and oftentimes computed tomography with tridimensional reconstruction to confirm that the fracture is malunited as opposed to nonunited and to try to understand whether the residual displacement truly contributes to the patient's symptoms. Some patients with limited forearm rotation in the setting of a malunion after internal fixation will improve their motion with release of the contractured tissue around the annular ligament and radial head, as well as hardware removal, without necessarily needing to correct the associated residual bone deformity.

Radial Head Nonunion

One or more fractured fragments may fail to unite after internal fixation of a radial head fracture. Nonunion at the neck level may be well tolerated and permit a reasonable arc of forearm rotation without major symptoms. Nonunion of fragments of the head oftentimes are associated with hardware failure that becomes prominent; typically, patients complain of pain, mechanical symptoms such as catching and locking, and various degrees of forearm rotation loss.

Limited Forearm Rotation

Loss of forearm rotation after internal fixation of a radial head fracture needs to be analyzed carefully. Associated injuries to the wrist or forearm that may have happened at the time of fracture can contribute to limited pronation and supination. Fracture malunion or nonunion may also contribute to limited forearm rotation. In many circumstances, it is mostly due to fibrosis and/or prominent hardware.

In patients with loss of forearm rotation initially attributed to a radial head fracture, secondary contractures of the interosseous membrane and the distal radioulnar joint may develop. The time frame and frequency for these secondary contractures to occur is largely unknown.

Some surgeons believe that the space between the proximal radius and the annular ligament is very sensitive to space-occupying hardware. A study completed at our institution demonstrated worse forearm rotation when fractures involving the radial neck were fixed with plates when compared to oblique screws ( Fig. 40.3 ). Studies that have reported good forearm rotation after internal fixation using plates have commonly reported a high rate of secondary plate removal prior to attaining satisfactory forearm rotation. Plate fixation may be the only method to obtain adequate osteosynthesis, but these facts should be taken into consideration when selecting fixation over arthroplasty, as well as when selecting the internal fixation technique.

FIG 40.3, (A,B) Some studies suggest that plate fixation is associated with a higher rate of limited forearm rotation. This is especially true when non–low-profile plates are selected.

Failed Radial Head Replacement

The usual mechanisms of failure after use of a prosthesis for treatment of a radial head fracture include overlengthening and missizing, loosening, infection, prosthesis disassociation, wear, stress shielding, and progressive cartilage erosion or osteopenia on the capitellar side of the joint.

The relative frequency of various failure mechanisms in patients subjected to revision radial head replacement was analyzed at our institution. In a consecutive series of 47 elbows in 44 patients, reasons for implant removal or revision included loosening (31 elbows), stiffness (18 elbows), instability (9 elbows), and infection (2 elbows). Of the 31 loose implants, only 3 had been fixed with cement.

Overlengthening and Poor Sizing

For quite some time, little attention was paid to accurate restoration of the overall length of the radius, sizing, and a number of design features that are now known to have major effects on the mechanics of the elbow joint and on the clinical and radiographic outcomes of radial head replacement. The design and surgical technique details required to achieve the best possible outcome with radial head replacement are discussed in Chapter 39 ( Box 40.1 , Fig. 40.4 ).

Box 40.1
Choosing Size and Length in Radial Head Replacement

  • Choose a design that allows independent selection of head diameter and prosthesis length

  • Avoid overlengthening by using one or more of the following:

    • Direct measurements on the resected radial head

    • Length gauges to avoid distraction at the ulnohumeral joint

    • Reference points (coronoid, lesser sigmoid notch)

    • Trial prosthesis

    • Intraoperative fluoroscopy

  • Select the minor diameter of the articular surface of the resected radius

FIG 40.4, Poor implant sizing and radius overlengthening are relatively common after radial head replacement. Note asymmetry of the ulnohumeral joint.

An overlengthened radius can lead to stiffness, progressive cartilage and bone loss in the capitellum, and persistent instability secondary to stretch of the lateral collateral ligament complex. Too large or too small of a radial head diameter can lead to poor tracking with instability or capitellar damage. It is important to emphasize that radiographic changes, including lateral ulnohumeral joint space widening, are not diagnostic of overlengthening, and plain radiographs may be inadequate to identify this complication in some patients.

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