Total elbow arthroplasty has become increasingly popular for the treatment of distal humerus fractures in elderly patients with poor bone quality, comminution, and/or pre-existent elbow abnormalities. The procedure is performed without violating the extensor mechanism; the fractured fragments are exposed and resected on both sides of the triceps, and the components can be implanted through the same exposure. Early outcomes are satisfactory in most elbows and compare favorably with internal fixation in this same group of elderly patients. Advances in elbow arthroplasty for fractures will likely combine refinement of the indications and development of implants with lower rates of failure.
Key points
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Total elbow arthroplasty provides a successful early outcome for most elderly patients with comminuted distal humerus fractures.
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The procedure typically involves resection of the fractured fragments, which allows implantation of the components without violation of the extensor mechanism.
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Life-long activity restrictions are recommended after elbow arthroplasty to minimize implant mechanical failure.
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Direct comparisons between internal fixation and arthroplasty for selected elderly patients with distal humerus fractures have shown better outcomes with arthroplasty.
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Mid-term and long-term studies do report several failures secondary to infection, loosening, and periprosthetic fractures.
Introduction
Fractures of the distal end of the humerus are serious injuries, with a high potential for a poor outcome and complications due to a combination of confounding factors ( Box 1 ). Internal fixation represents the standard of care for most distal humerus fractures. However, total elbow arthroplasty has become increasingly popular for selected elderly patients when stable internal fixation is difficult to achieve due to osteopenia and comminution or to preexisting arthritic changes at the elbow. Hemiarthroplasty of the distal humerus has also been contemplated for prosthetic replacement after distal humerus fractures. However, the current published experience is limited, and the role of hemiarthroplasty is not covered in this article.
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Complex geometry of the distal humerus
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Involvement of the articular cartilage
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Comminution
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Osteopenia
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Exposure through the extensor mechanism
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Risk of ulnar neuropathy
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Risk of heterotopic ossification
Introduction
Fractures of the distal end of the humerus are serious injuries, with a high potential for a poor outcome and complications due to a combination of confounding factors ( Box 1 ). Internal fixation represents the standard of care for most distal humerus fractures. However, total elbow arthroplasty has become increasingly popular for selected elderly patients when stable internal fixation is difficult to achieve due to osteopenia and comminution or to preexisting arthritic changes at the elbow. Hemiarthroplasty of the distal humerus has also been contemplated for prosthetic replacement after distal humerus fractures. However, the current published experience is limited, and the role of hemiarthroplasty is not covered in this article.
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Complex geometry of the distal humerus
- •
Involvement of the articular cartilage
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Comminution
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Osteopenia
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Exposure through the extensor mechanism
- •
Risk of ulnar neuropathy
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Risk of heterotopic ossification
Rationale, pluses, and minuses
Joint replacement is an accepted alternative for selected periarticular fractures, such as femoral neck, radial head, or proximal humerus fractures. As total elbow arthroplasty demonstrated a satisfactory track record for end-stage inflammatory arthritis, its indications were expanded to other conditions, including selected fractures of the distal humerus.
Total elbow arthroplasty is indicated in elderly patients with distal humerus fractures with preexistent symptomatic pathologic abnormality (ie, a fractured rheumatoid elbow), low comminuted fractures with underlying osteopenia, and severe damage to the articular surface. It is contraindicated in fractures amenable to stable internal fixation, open fractures, and patients with anticipated high physical demands. The relative advantages and disadvantages of internal fixation and arthroplasty are summarized in Table 1 .
| Internal Fixation | Total Elbow Arthroplasty | |
|---|---|---|
| Advantages | Durable No restrictions No prosthetic-related complications | Bone union not needed Quick return to ADLs Easier recovery Avoids nonunion/DJD |
| Disadvantages | Risk of nonunion Risk of posttraumatic DJD Risk of stiffness Requires intensive physical therapy | Mechanical failure Restrictions Higher infection rate |
Surgical technique
The management of the fractured fragments at the time of total elbow arthroplasty has been a matter of controversy in the past. The origin of the medial and lateral collateral ligament complexes is typically located in the fractured condyles. Implants that depend on the collateral ligaments for stability, or the condylar bone for implant fixation, may need to combine the arthroplasty with internal fixation of the fractured columns. However, this strategy requires more exposure, increases the complexity of the procedure, and requires fracture union for success.
Dr Bernard Morrey pioneered a completely different surgical strategy: the fractured fragments are resected and elbow stability is reestablished by using a linked implant designed so that humeral fixation does not require the integrity of the condyles ( Fig. 1 A). The working space created by removing the fractured distal humerus provides enough exposure to prepare the humerus and ulna, and to implant the prosthetic components. Interestingly, removal of the origin of the forearm muscles both medially and laterally has not been demonstrated to impact grip, forearm strength, or elbow strength substantially. McKee and colleagues compared 16 elbow replacements with preservation and 16 with resection of the condyles and found no differences in motion or strength. Because the extensor mechanism is not violated, the implants are cemented and linked, and bone union does not need to happen, patients can return to activities of daily living quickly, a major benefit in an elderly patient population that can hasten a quicker return to function and independence.
Exposure
The authors favor the use of a sterile tourniquet to avoid contamination of the surgical field if proximal extension of the skin incision is required. In the authors’ practice, the ulnar nerve is routinely transposed in an anterior subcutaneous pocket. The posterior aspect of the joint is exposed under the triceps. The medial fractured fragments are resected subperiosteally, taking care to protect the integrity of the origin of the common flexor-pronator group (see Fig. 1 A). The lateral fractured fragments are resected subperiosteally as well through Kocher interval. Most of the time, it is easier to deliver the humeral shaft through the medial window.
Component Implantation
Preparation of the humeral canal is straightforward using the instrumentation system of choice (see Fig. 1 B). Ulnar preparation is more difficult with the triceps still attached to the olecranon, which is partly due to the bulk of the extensor mechanism and partly to the difficulty in rotating the forearm to provide exposure (see Fig. 1 C). A helpful trick consists of raising subperiosteally off the olecranon approximately 20% of the triceps tendon from medial to lateral; by rolling the medial edge of the triceps laterally, the ulna is easier to rotate, and the integrity of the extensor mechanism is not markedly compromised.
Careful attention should be paid to component implantation in terms of both depth of insertion and rotation. On the ulnar side, the depth of insertion is easy to determine because the tip of the olecranon and the coronoid provides a very accurate reference; the component is inserted such that the center of rotation is equidistant from these 2 points. Rotationally, the ulnar component needs to be placed parallel to the flat dorsal aspect of the olecranon.
On the humeral side, depth of insertion may be referenced off the roof of the olecranon fossa, but should be confirmed with intraoperative trials to assess soft tissue tension. With the trials in place and the elbow in 90° of flexion, moderate distraction can be applied by pulling up on the forearm, and the resting position of the humeral trial may be recorded. The elbow should then be confirmed to extend fully, but without hyperextension. Humeral component rotation can be based off the posterior cortex, although there may be a difference of approximately 15°.
The authors favor adding antibiotics and a catatonic dye to the bone cement used for fixation (1 g of vancomycin and 1 mL of methylene blue per batch of cement). Both canals are occluded with cement restrictors or a bone fragment, and the components are cemented in the desired position (see Fig. 1 D). Once the cement has hardened, the implants are linked; the Kocher interval is repaired, and the common flexor-pronator group is carefully repaired to the medial triceps in an attempt to seal the joint fully ( Fig. 2 ).
Related posts:
The Clinical Outcome of Patellofemoral Arthroplasty
Treatment of Articular Fractures with Continuous Passive Motion
Management of Radial Nerve Palsy Following Fractures of the Humerus
Bicompartmental Knee Arthroplasty
Operative Techniques in the Management of Scapular Fractures
Posterior Elbow Wounds
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