INTRODUCTION

Distal humeral hemiarthroplasty (DHH) was first described in 1947, yet over the past 60 years there have been only a few small series reporting on this technique.^{1,14,17,25–28} Early series reported treatment of a variety of pathologic conditions, including trauma, inflammatory arthritis, and tumor. Prostheses included both custom-made (of various materials) and nonanatomic humeral components from total elbow systems (capitellocondyllar, kudo) and anatomic components (Street). These early surgeries met with mixed results. The past decade has witnessed renewed interest in DHH with advancements in our understanding of elbow biomechanics and with growing experience in the difficulty of achieving effective outcomes in treating complex distal humerus fractures. This technique provides a treatment alternative that bridges the gap between internal fixation and total elbow arthroplasty (TEA) in unsalvageable distal humeral articular surface pathologies.

INDICATIONS AND CONTRAINDICATIONS

The indications for DHH are evolving, both in terms of what is achievable and what is appropriate (Table 52-1). Initial experience has been in the younger patient or the physically active older patient with a comminuted intra-articular distal humeral fracture (sometimes combined with a column fracture) that involves both trochlea and capitellum, where an adequate reduction and internal fixation cannot be achieved. Open reduction internal fixation (ORIF) remains the gold standard of operative treatment; however, patient factors and bone architecture may limit the surgeon’s ability to reconstruct the elbow. Series reporting on ORIF of comminuted intra-articular fractures indicate a substantial rate of unsatisfactory outcomes and a significant complication rate in complex cases.^{1,14,17,23,24}

TABLE 52-1 Indications and Contraindications for Humeral Hemiarthroplasty

Total elbow arthroplasty has gained acceptance as a primary treatment option for intra-articular distal humeral fractures in lower demand, elderly patients with osteopenic bone.^{4,9–11,20,22} Its application to younger active patients is attendant with the risk of early prosthesis failure.

Current indications for DDH include (1) acute trauma, (2) salvage of failed internal fixation, (3) chronic malunion or nonunion, (4) avascular necrosis of the trochlea with collapse of subchondral bone, and (5) tumors of the trochlea where resection allows preservation of the epicondyles and collateral ligaments. The use in inflammatory joint disease may need to be revisited. Early use of hemiarthroplasty with rheumatoid arthritis resulted in a stiff painful joint. However, there may be a role in the young patient with “burnt-out” inflammatory joint or the patient on disease-modifying agents in whom the joint is eburnated and the architecture relatively congruent.

Contraindications to DHH include overt local or distant foci of infection; inadequate neurovascular status; insufficient bony column support, especially epicondyle or condylar comminution resulting in implant instability; and poor soft tissue coverage. An intact radial head and coronoid are essential for adequate joint stability. Articular cartilage damage of the radial head and sigmoid fossa due to chronic fracture arthrofibrosis or inflammatory arthropathy may lead to inadequate pain relief, less function, and uncertain longevity. This represents a relative contraindication that may favor a linked TEA. Developmental humeral insufficiency resulting in a nonanatomic ulna architecture, such as a “fishtail deformity,” is a contraindication to DHH.

PRINCIPLES OF DISTAL HUMERAL HEMIARTHROPLASTY

Stability of the intact elbow joint is provided by ulnohumeral congruity,¹⁸ a competent radiocapitellar articulation, and collateral ligament integrity.⁵ Because DHH is an “unlinked” reconstruction, the prosthesis must have a high degree of congruency with the radius and ulna to provide stable force transmission through both medial and lateral articular columns; therefore, sizing is important. For the DHH to function optimally, the prosthesis must be oriented such that the elbow rotation axis relative to the insertions of the anterior band of the medial collateral ligament (MCL) and lateral ulnar collateral ligament (LUCL) is restored.³ This ensures that the ligaments remain isometric through a functional range of motion. The proper joint rotation axis can be determined by surface landmarks, medially at the anterior inferior surface of the medial epicondyle and laterally at the center of a circle formed by the articular surface of the capitellum.^{2,5–8,19,21}

Given these considerations, the prerequisites for implantation of a DHH include (1) the ability to reconstruct both medial and lateral columns; (2) intact or stable reconstruction of the radial head and coronoid process; and (3) intact or reparable MCL and LUCL. Good exposure (e.g., olecranon osteotomy) is generally required to achieve all these goals.

IMPLANT CONSIDERATIONS

There are currently two systems available (and an additional one, Coonrad/Morrey [Zimmer, Warsaw, IN] under development) that allow DHH with a prosthesis based on normal articular geometry (Fig. 52-1): (1) the Sorbie Questor elbow system (Wright Medical Technologies, Arlington, TN) and (2) the Latitude elbow system (Tornier, Stafford, TX). All require cement fixation and, because they may be subjected to significant forces, optimal cementing techniques should be used.⁷ The Sorbie Questor humeral component is a monoblock anatomic prosthesis with three sizes (small, medium, and large) that allow a “best fit” in 95% of all elbows.²⁹ It allows fixation of comminuted bone fragments of either supracondylar column. There is no anterior flange or long-stem option to augment humeral fixation. This system allows conversion only to an unconstrained TEA, which may not address future instability issues. Mechanical studies of the Sorbie humeral component indicate that an intact radial head is necessary for elbow stability despite an intact MCL.¹³ It is attractive because it removes little bone and is relatively easy to insert.

FIGURE 52-1 A, Sorbie Questor hemiarthroplasty. B, Latitude prosthesis with anatomic spool.

The Latitude system has three stem sizes that articulate with six sizes of modular anatomic spools. The central stem has medial and lateral column extensions that house an axis pin, which facilitates positioning of the component relative to the collateral insertions before insertion. Although reconstruction of the epicondyles with the attached collateral ligaments is the preferred technique, a hole through the central axis of the prosthesis permits suture fixation of the collateral ligaments if stable bony architecture of the ligament insertions is not possible. An anterior flange allows bone grafting to reduce the risk of prosthesis loosening. Added modularity allows conversion to either an unlinked or a linked TEA.

PREOPERATIVE PLANNING

Preoperative imaging studies should include anteroposterior (AP) and lateral views of the elbows. Plain radiographs of the contralateral elbow permit additional templating of the distal humerus for appropriate prosthesis sizing. Sizing is based on the direct correlation between the AP dimensions of the normal articular surface and the radii of the capitellum and trochlea (Fig. 52-2).²⁶ Preoperative assessment might also include a fine-cut computed tomography (CT) scan to evaluate articular comminution, column involvement, and associated injuries to the radial head and coronoid (Fig. 52-3).

FIGURE 52-2 The anteroposterior radiograph is templated to ensure anatomic reconstruction and to avoid mismatch or overstuffing of the joint. The longitudinal axis of the radial neck should align with the center of the capitellum with the sigmoid fossa being congruent with the prosthesis.

FIGURE 52-3 A, Comminuted fracture of the distal humerus in a 53-year-old woman. Computed tomography scan more accurately defines the degree of comminution and trochlear involvement. B, Posterior exposure via a chevron osteotomy with preservation of the collateral ligaments. The axis of the prosthesis is aligned with the collateral ligament attachments. C, Anteroposterior x-ray study of Latitude hemiarthroplasty.

Except in cases in which a decision has been made to proceed directly to TEA, we approach all distal humerus fractures with the aim of internal fixation. In complex cases, the necessary instruments for both internal fixation and hemiarthroplasty are available in the operating room and the decision to perform DHH is made on surgical inspection of the fracture. In many cases, combined techniques are used if column fixation is necessary to stably implant the humeral prosthesis, including precontoured periarticular plates, threaded Kirschner wires (K-wires), and tension band sutures. Newer locking plates allow insertion of short, unicortical screws to allow passage of the prosthetic stem in the humeral canal.

Timing of the procedure is not crucial, as long as the procedure is undertaken in 7 to 10 days after acute fracture to lessen the possibility of heterotopic ossification.

OPERATIVE TECHNIQUE

The patient is positioned in the lateral decubitus position. A tourniquet is applied and the arm secured to a short arm support. This allows flexion of the arm to 120 degrees, which facilitates insertion of the component. This also places the posterior aspect of the distal humerus parallel to the floor, when the elbow is flexed 90 degrees. A large sterile basin is placed beneath the arm to catch any bone fragments or instruments. The elbow is approached through an extensile posterior incision, and thick subcutaneous flaps are developed to provide access to both epicondyles and columns. The ulna nerve is exposed and protected. A Chevron osteotomy of the olecranon is performed at the level of the sigmoid fossa bare area, and the triceps mechanism is reflected sufficiently proximal to expose any supracondylar fracture extension (see Chapter 7). “Triceps-on” exposures provide poorer exposure and are associated with increased joint instability. During exposure, the humeral insertions and origins of the MCL and LUCL must be preserved.

Once exposed, the articular surface can be inspected. If the combination of fracture comminution, osteopenia, and patient considerations favors DHH then trial components should be templated with the radial head and anterior sigmoid fossa to confirm proper fit and to avoid overstuffing of the joint. Injury to the radial head, coronoid, and collateral ligaments must be identified to proceed with this option and to ensure a stable reconstruction (see Fig. 52-3).

We have currently extended the indications even to those with fractured supracondylar columns. This may not be appropriate for all surgeons to consider, but if this type of pathology is undertaken, before any supplemental column fixation, the humeral canal is opened with a burr and broached. Inserting a trial humeral component will help prevent comprising the canal with ORIF implants. Column reduction must be anatomic so that the insertions of the collateral ligaments will allow proper restoration of the rotation axis. After provisional K-wire fixation, the appropriate precontoured plate is applied if fixation is inadequate.

Next, the bone cuts must be made so that the prosthesis can be inserted to the proper depth and rotation to recreate the flexion axis. Free-hand cuts are generally preferred because bone loss from fracture comminution complicates accurate placement of the cutting jigs.

The trial prosthesis of appropriate size is inserted. Strict attention should be paid to the depth of insertion and rotation when the trial is seated because this determines ligament tension. Once the trial is in place, the ulna is reduced over its articular surface and the joint taken through a range of motion. Difficulty reducing the ulna suggests that the flexion axis is too distal, and the humeral cuts should be revised to prevent an overly tight reconstruction. The tracking of the anterior half of the olecranon during elbow flexion and extension can also provide a sense of the correct prosthesis rotation (Table 52-2).

TABLE 52-2 Pitfalls and Complications of Hemiarthroplasty

A cement restrictor should be used to provide good pressurization of the antibiotic cement. The final prosthesis is then inserted to the correct position. The ulna is reduced to the distal humeral prosthesis, and the elbow is extended (not cycled) until the cement is cured. The olecranon osteotomy is fixed using a tension band or a periarticular olecranon plate and always grafted with autologous bone from the trochlea (Fig. 52-4). Although the plate provides the best fixation (and therefore allows more aggressive early mobilization), there are times when soft tissue considerations prevent its use. The elbow should then be taken through a range of motion to ensure the following: (1) motion has not been constrained by an overly tight reconstuction; (2) the olecranon osteotomy remains reduced as tension develops in flexion; and (3) the ulna nerve does not develop undue tension or encroachment by neighboring hardware. The nerve is transposed as necessary.

FIGURE 52-4 Fixation of the olecranon osteotomy with a contoured plate.

TREATMENT OF NONACUTE INJURIES

Hemiarthroplasty may also be used as a salvage reconstruction in cases of malunion, fixation failure, or nonunion after open reduction internal fixation. In these instances, the principles of the reconstruction are the same in terms of restoring the column architecture, preserving the collateral ligaments and recreating the rotation axis (Fig. 52-5). A thorough surgical débridement is essential, and in the case of nonunion, tissue should be sent for histopathology and microbiology assessment to rule out infection. Once tissue is obtained, regional infusion of antibiotics is performed to provide optimal tissue levels in already compromised soft tissues. If supracondylar bone loss is present following débridement, a shortening osteotomy may be required, along with medial and lateral plate fixation. Autologous bone graft is routinely used to promote bony union (Fig. 52-6). The ability to achieve a stable reconstruction should be carefully considered in these complex cases in which bony and soft tissue anatomy may have been significantly altered by prior injury and treatment. If concern exists about this ability then a linked TEA may offer a more reliable reconstructive option. Articular cartilage damage of the radial head and sigmoid fossa due to arthrofibrosis or inflammatory arthropathy may lead to inadequate pain relief, reduced functional outcomes, and uncertain longevity. This represents a relative contraindication that may favor a linked TEA. Thus, if a DHH is planned, it probably should be undertaken early rather than late in a failed ORIF.

FIGURE 52-5 A 26-year-old man with compound traumatic loss of trochlea and capitellum, fractured radial head and coronoid, treated with débridement, internal fixation of radial head and coronoid, and application of external fixator in distraction. At 3 months, a hemiarthroplasty via an olecranon osteotomy was performed. A and B, Initial fixation of the radial head and a external fixator. C, Latitude hemiarthroplasty with united radial head.

FIGURE 52-6 A, Established nonunion with associated avascular necrosis of the lateral trochlea, requiring column reconstruction with periarticular plates and bone grafting. B, Intraoperative fluoroscopic assessment.

POSTOPERATIVE PROTOCOL

Patients start passive range of motion from 20 to 100 degrees, using either continuous passive motion or hourly, self-guided flexion, extension, pronation and supination. Night-time extension splinting is commenced early and changed at 6 weeks to a padded turnbuckle in patients with a significant flexion contracture. Active assisted flexibility exercises are begun at 4 to 6 weeks, along with antigravity extension exercises. Active use of the arm for daily functions is discouraged for 6 weeks if a column fixation was performed as part of the reconstruction. Serial radiographs are obtained to follow healing of the olecranon osteotomy and any other internal fracture fixation. Pending adequate healing, resistive strengthening is withheld until 10 to 12 weeks.

PITFALLS AND COMPLICATIONS

Potential pitfalls and corresponding considerations and solutions are listed in Table 52-2. Many of these pitfalls can be addressed by meticulous surgical technique, a thorough understanding of elbow biomechanics, and knowledge of the prosthesis systems as they relate to restoring articular geometry and elbow stability.

Joint stiffness may occur despite a properly performed reconstruction and early mobilization. If stiffness remains unresponsive to static night splinting, then dynamic splinting can be considered at 2 to 3 months. Persistent stiffness despite these efforts can be managed with contracture release by a column approach at 6 to 12 months postoperatively. Heterotopic ossification, although not common, may occur in the setting of severe elbow trauma (Fig. 52-7A). This is managed by excision and contracture release when the bone is radiographically mature. Instability appears to be related to triceps on exposures, epicondyle comminution, and incorrect collateral ligament reconstruction (see Fig. 52-7B).

FIGURE 52-7 Complications. A, Heterotopic ossification following distal humeral hemiarthroplasty in acute fracture. Should it result in functional loss of movement, it can be resected with predictable good results. B, Instabilty due to inadequate lateral column/lateral collateral ligament reconstruction, requiring urgent revision fixation.

Late complications can include the development of arthrosis of the sigmoid notch due to mismatch with the size or orientation of the prosthesis. If these patients have disabling mid-arc pain, conversion to a linked TEA may be necessary. Implant loosening, periprosthetic fracture, and late infection are also possible.

RESULTS

Table 52-3 lists the series of DHH to date. Although long-term prospective data are lacking, except in a few anecdotal case reports, early experience has yielded several observations. First, DHH can lead to substantial pain relief and improvement in function after complex distal humerus fractures. Second, treatment of acute fractures generally results in more favorable outcomes than salvage reconstruction of nonunion, malunion and hardware failure. Third, DHH has proven less effective in chronic conditions such as inflammatory arthritis and hemophilia. Repeat procedures are usually related to hardware removal for fracture or osteotomy fixation. Revision of components is relatively simple especially with the modular systems that can be converted to linked TEA. Future prospective evaluation will better define indications, technique, restrictions and the long-term effectiveness of DHH.

TABLE 52-3 Results of Hemiarthroplasty

CONCLUSION

Treatment of complex distal humerus fractures or loss of trochlea architecture can be demanding. Although internal fixation and TEA have proven effective in many cases, there are circumstances for which neither represents an ideal treatment. These circumstances include younger or physically active patients. DHH offers an alternative that can provide immediate stability and early mobilization with less risk of implant failure compared with a linked TEA. This is a technically demanding procedure that requires experience with both distal humeral fracture fixation and TEA. Combined techniques may be necessary to restore column architecture and resurface the joint. All supplemental fixation must be rigid enough to allow early motion so that the postoperative recovery from DHH can be reduced to the management of the olecranon osteotomy. Based on early encouraging results, we believe that this is a valuable technique that merits continued refinement through surgical experience and ongoing prospective studies. Our experience indicates a more reliable outcome in the acute (80%) than in the delayed, reconstructed (50%) elbow.¹⁶

INTRODUCTION

Recognition and focused management of radiohumeral joint arthrosis has emerged over the past several years. Herein we describe the concept and the rationale for capitellar replacement, placing this option in the context of other potential nonprosthetic interventions. One feature that characterizes virtually all of these possibilities is the lack of clinical data of outcomes at this point in time. With the next edition of the book, this whole topic will be much better elucidated. The reader should bear in mind that the information offered here is principally to call attention to the process and to highlight emerging options without claiming at this time that this is the ultimate or final solution to the problem.

ETIOLOGY

Like so many other pathologic conditions, it seems as though the process is more frequent once we are attuned to investigate for its presence. In general, as a condition, primarily osteoarthritis at the elbow, generally considered uncommon in the past, is today well recognized in the orthopedic community.^3,6,10,11 Pathology of the radiohumeral joint occurs from primary osteoarthritis, as a sequelae to osteochondritis dissecans, following capitellar fracture, or secondarily to radial head fracture either ignored, treated by open reduction and internal fixation, or by prosthetic replacement. Finally, the condition is seen after split T and Y type of fractures of the distal humerus resulting in malalignment (Fig. 52-8).

FIGURE 52-8 Radiohumeral arthritis with primary involvement of the capitellum after capitellar fracture is treated by resection (A). The distal T-condylar fracture resulting in isolated radiohumeral involvement (B).

The frequency and impact of these various conditions is not readily available in today’s literature. There has been some interesting studies referable to primary osteoarthritis of the radiohumeral joint that are worth noting. Ortner¹³ examined the elbow of a population of Eskimos and South American Indians. As a result of this investigation, the authors describe several forms of osteoarthritis at the radiohumeral joint including (1) hypertrophic bone formation peripheral to the articular surface; (2) hypertrophic bone formation in the radial fossa; (3) increased porosity and hypertrophy of the lateral condylar ridge; (4) porosity of the capitellum and; (5) eburnation of the capitellum. These authors note interestingly and accurately that the narrowing of the ulnohumeral joint is not a characteristic of primary osteoarthritis but is more frequently seen at the radiohumeral joint. On the other hand, the osteophyte formation is more commonly observed in the margin of the trochlea and at the coronoid and tip of the olecranon. Subsequently, Goodfellow et al¹¹ documented the increasing incidence of osteoarthritis of the radiohumeral joint with aging and emphasized the early development of the process at the posterior medial ridge separating the trochlea and the capitellum (Fig. 52-9).⁴ Occupation risks in foundry workers was documented. In general, heavy, repetitive use of the extremity places the joint at risk.

FIGURE 52-9 In some instances joint narrowing of the radiohumeral joint is exhibited as shown by the radiograph and CT (A and B).

Typically, this process appears to be relatively asymptomatic, but with enhanced awareness and closer scrutiny, the presence of radiohumeral joint symptoms is being increasingly appreciated. These observations have been confirmed somewhat in the recent documentation of intervention for primary osteoarthritis of the elbow. Kelly et al⁷ described radiohumeral narrowing and instances in which the ulnohumeral joint was débrided arthroscopically. They noted that the radial humeral involvement often typically appears to be well tolerated and need not be directly assessed. Others emphasize the technical ability to débride the ulnohumeral joint but do not comment to any extent on the radiohumeral joint. Although both closed^7–9 and open procedures^1,14,16 are well-accepted means of treating primary osteoarthritis of the elbow, few make reference specifically to the management of the radial head.^7,9 Radiographically, however, the radial head involvement has been documented by Dalal.² In this study of 50 patients with primary osteoarthritis, radial head involvement was present in approximately 85% but was not typically symptomatic. Some narrowing of the joint was present in approximately 60% compared with only 15% narrowing of the ulnohumeral joint. Savoie’s group is one group that has addressed the radiohumeral component of primary osteoarthritis. These authors perform radial head resection through the arthroscope and, in so doing, document improved motion in both flexion and extension and pronation and supination.⁹ The long-term impact, however, of removing the radial head in the presence of ulnohumeral joint arthrosis is unknown. This is one of the major issues that prompts one to consider possibly replacing this joint if it is symptomatic enough to deserve treatment on its own merits.

TREATMENT OPTIONS

Experience to date on the treatment of isolated radiohumeral arthrosis or particularly a capitellar arthritis is limited. In general, the treatment options include débridement versus reconstruction. The reconstructive options have relatively little data, but these consist of resecting the capitellum, analogous to isolated resection of the radial head but with little data regarding its outcome. Débridement is effective in those with symptomatic osteochondritis dissecans, particularly when the fragment is loose and causing mechanical symptoms (see Chapters 19 and 38).

Biologic interposition arthroplasty or prosthetic replacement of the capitellum and/or the capitellum and radial head is a consideration. When the capitellum has been destroyed as a result of fracture, often with resorption, a unique problem exists for which there is no good solution. We have performed allograft replacement with or without interposition arthroplasty in a few of these patients. We have also performed an anconeus rotational plasty in patients with deficient or arthritic capitellum and this does seem to be an effective modality. This procedure does not, however, provide axial stability.¹² Without question, one of the greatest problems with the radiohumeral joint relates to problems at the articulation after the radial head has been fractured and treated by fixation or prosthetic replacement. Under these circumstances, the radial head is typically excised or the prosthesis is removed. If the medial collateral ligament is stable, this is adequate treatment. If, however, the medial collateral ligament is unstable, then the major indication for consideration of a prosthetic implant exists. This is intended to satisfy the need to stabilize the “lateral column” in instances in which there is deficient medial collateral ligament or axial instability such as an Essex-Lopresti lesion. There is some, but limited, experience with prosthetic replacement to date (Pooley J, personal communication).

ANCONEUS ARTHROPLASTY

Indications

In general, this technique is employed in instances when the proximal radial ulnar or ulnohumeral dysfunction occurs following trauma or resection, or after primary osteoarthrosis. This procedure was designed for two clinical circumstances: (1) radiohumeral impingement, in which the goal is to buffer the proximal radiocapitellar articulation; and (2) rotatory radioulnar impingement.

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