CHAPTER SYNOPSIS:

This chapter examines the indications, surgical technique, complications, and expected outcomes of total elbow arthroplasty (TEA). The Coonrad-Morrey and Discovery prostheses are highlighted.

IMPORTANT POINTS:

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  Semiconstrained TEA can be used even with poor bone stock or ligamentous instability.

  
  
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  Indications include significant pain, stiffness, or instability from inflammatory arthritis, osteoarthritis, or posttraumatic conditions not amenable to more conservative treatment.

  
  
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  Absolute contraindications include active infection and inability or unwillingness of the patient to comply with the short- or long-term activity restrictions. Strong relative contraindications requiring surgical correction include loss of active elbow flexion and inadequate soft tissue coverage. Other relative contraindications include a history of deep elbow infection, younger patient age, and higher patient activity level.

  
  
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  Long-term followup recommended.

CLINICAL/SURGICAL PEARLS:

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  An approach is selected based on preoperative evaluation of the patient and surgeon experience.

  
  
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  Attention to detail in the perioperative period reduces infection and other early complications.

  
  
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  Active flexion and active or passive extension are initiated in the early postoperative period.

CLINICAL/SURGICAL PITFALLS:

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  Complications include aseptic loosening, ulnar neuropathy, infection, intraoperative fracture, bushing wear, and implant fracture.

  
  
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  Patient selection is key.

VIDEO:

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HISTORY/INTRODUCTION/SCOPE OF THE PROBLEM

Over the past 30 years better implant design and advances in surgical technique have improved implant survivorship. Total elbow arthroplasty (TEA) can relieve pain, improve elbow motion and stability, and improve function, often allowing patients to comfortably perform basic activities of daily living. Linked prostheses allow the use of TEA in patients with significant bone and ligamentous deficiency.

Early hinged elbow prostheses were fully constrained, and studies showed a high rate of mechanical loosening. Continued design evolution and improvements in surgical technique have resulted in significantly better outcomes. However, the expected longevity of an elbow replacement is highly dependent on patient selection, and some studies continue to report alarmingly high rates of complications. Loosening and mechanical failure remain a significant clinical problem, especially for younger, more active patients.

Improvements in implant design that have led to significant improvements in TEA outcome include the “sloppy hinge,” the anterior humeral flange, and new porous implant coatings that optimize implant fixation. The “sloppy hinge” refers to the 8 to 10 degrees of varus–valgus laxity incorporated into the ulnar–humeral coupling. Newer linked TEAs also allow rotation about the longitudinal axis of the humerus. This laxity transfers some of the stresses to the soft tissues surrounding the joint, reducing the stress at the prosthesis–cement and cement–bone interfaces. A long anterior flange (e.g., Coonrad-Morrey III) reduces stress on the posterior humeral cortex and transfers some of the torsional stress away from the prosthesis–cement and cement–bone interfaces.

CLASSIFICATION SYSTEM

The simplest classification system of elbow replacement implants is “linked,” referring essentially to hinged implants, and “unlinked,” in which the humeral and ulnar components articulate but are not directly connected. “Semiconstrained” is a term generally used to refer to modern linked implants that allow for some varus–valgus laxity. “Convertible” systems allow the surgeon to implant either a linked or unlinked prosthesis based on intraoperative findings of stability, with the option of later converting an unlinked prosthesis to a linked configuration without complete implant removal.

INDICATIONS/CONTRAINDICATIONS

Patients with significant elbow dysfunction resulting from pain, stiffness, or instability that is not responsive or amenable to medical or more conservative surgical treatments may be considered for elbow arthroplasty. The severely affected elbow in rheumatoid arthritis (RA) has been the most common and best accepted indication for TEA ( Figs. 21-1 to 21-4 ). Recently published longer term studies (10 or more years) suggest that survival rates for TEA in rheumatoid arthritis are approaching those of knee and possibly even hip arthroplasty.

Severe rheumatoid arthritis affecting the elbow—AP.

(Courtesy of Dr. George Athwal.)

Severe rheumatoid arthritis affecting the elbow—lateral.

(Courtesy of Dr. George Athwal.)

Coonrad-Morrey elbow prosthesis—AP.

(Courtesy of Dr. George Athwal.)

Coonrad-Morrey elbow prosthesis—lateral.

(Courtesy of Dr. George Athwal.)

Radial head excision and synovectomy (RHES) and interposition arthroplasty remain essential tools in the surgical treatment of rheumatoid arthritis of the elbow, but the role of primary TEA, especially in the elderly patient and in more severe disease, appears to be expanding. Recent studies suggest that TEA may lead to better long-term pain relief than RHES and more durable long-term results than interposition arthroplasty. Although previous RHES was associated with an increased risk of instability of subsequent unlinked TEA, no effect was found on the long-term outcome of TEA after RHES when a linked, semiconstrained (Coonrad-Morrey) prosthesis was used.

Besides RA, indications for TEA currently include (in order of frequency) posttraumatic arthritis; JRA; distal humeral nonunions and severe comminuted distal humerus fractures, especially in the elderly; and primary osteoarthritis (OA). Disease severity, prosthesis choice, and patient adherence to limitations of use have a significant impact on the outcome of the procedure. Therefore, patient selection is critically important for all of the previously listed indications.

In low demand, elderly patients, TEA has been shown to provide improved and more predictable initial outcomes when compared to open reduction and internal fixation (ORIF) of severely comminuted distal humerus fractures ( Figs. 21-5 to 21-8 ). Nonunions of the distal humerus that cannot be reconstructed with ORIF because of poor bone quality or articular damage may be considered for TEA. TEA may also provide improved function for the grossly unstable elbow, which, as a result of bone loss involving the coronoid or humeral condyles, cannot be stabilized with ligament reconstruction.

Comminuted distal radius fracture in an elderly woman—AP.

(Courtesy of Dr. George Athwal.)

Comminuted distal radius fracture in an elderly woman—lateral.

(Courtesy of Dr. George Athwal.)

Coonrad-Morrey elbow arthroplasty for acute distal humerus fracture—AP.

(Courtesy of Dr. George Athwal.)

Coonrad-Morrey elbow arthroplasty for acute distal humerus fracture—lateral.

(Courtesy of Dr. George Athwal.)

The surgical indication influences the choice of prosthesis. The integrity of the soft tissues surrounding the joint is the most important factor in stabilizing an unlinked prosthesis. In rheumatoid arthritis, the soft tissues supporting the joint tend to deteriorate with time and disease progression. For this reason, semiconstrained (linked) prostheses have been shown to be more stable in the long term. The soft tissues may also be compromised in tumor reconstruction, primary OA, posttraumatic arthritis, and any elbow that is grossly deformed or ankylosed.

Absolute contraindications are active infection and inability or unwillingness of the patient to comply with the short- and long-term lifestyle restrictions. Functional deficiency of the elbow flexors is a strong relative contraindication but can be overcome in some cases by muscle transfer procedures. Inadequate soft tissue coverage or severe soft tissue scarring is also a relative contraindication but can often be addressed by a soft tissue procedure, either prior to or concurrent with the joint replacement surgery.

Although a history of deep elbow infection was once considered an absolute contraindication to TEA, Yamaguchi and colleagues published a series of 10 previously infected elbows with a salvage rate (excellent outcome) in 80%. Therefore, TEA may be considered in selected patients with a history of elbow infection if deep cultures remain negative after 2 years, depending on the patient’s medical condition and the virulence and susceptibility of the organism.

Total elbow arthroplasty is relatively contraindicated in younger (life expectancy of greater than 30 years ), more active patients. Survivorship of implants is better in low-demand patients whose function is compromised by diffuse disease (e.g., rheumatoid arthritis) compared to patients with isolated elbow symptoms (e.g., posttraumatic or osteoarthritis), who do not have any other physical disability that reduces demand on the implant. Therefore, low-demand patients with diffuse disease can be considered for TEA at a relatively younger age. A successful elbow implant can be expected to last 10 to 20 years prior to need for revision surgery.

SURGICAL TECHNIQUE

The approach for total elbow arthroplasty must provide adequate exposure while allowing protection of neurovascular structures. The ideal exposure preserves adequate joint stability and security of muscular attachments for early postoperative mobilization, decreasing the risk of stiffness. Approaches generally use a posterior skin incision and differ in the management of the triceps mechanism. Approaches are listed in Table 21-1 . The medial triceps-reflecting approach is described later in this chapter in conjunction with the technique for the Coonrad-Morrey prosthesis. Hastings has described a new triceps and ulnar collateral ligament-sparing approach specific for use with the Discovery Elbow System (Biomet Orthopedics, Warsaw, IN). This is the authors’ preferred approach. It will be further described later with the technique for that implant.

The technique of bone preparation and hardware implantation is dependent on the implant chosen. The authors have chosen to discuss the techniques for the Coonrad-Morrey and the Discovery prostheses ( Fig. 21-9 ). Developed at the Mayo Clinic, the Coonrad-Morrey elbow prosthesis has been used since 1981. As far as the authors are aware, it offers the broadest and longest (in followup) published body of experience of all elbow implants in the English literature. The Discovery prosthesis offers a number of design advantages and is most commonly used in our institution.

The Discovery Prosthesis

(Courtesy of Dr. Hill Hastings.)

PREOPERATIVE EVALUATION

Preoperatively, a thorough history and clinical examination aids the surgeon in preparation for the planned procedure. The details of previous surgeries are reviewed, with special attention to transposition of the ulnar nerve and previous manipulation of the triceps. Physical examination is used to determine the neurovascular status of the limb. The position, stability, and function of the ulnar nerve are determined. The operative site is carefully examined, noting the condition of the skin and soft tissues, the location of scars from previous surgery, and any deformity. Elbow stability and range of motion are determined.

Anteroposterior (AP) and lateral radiographs of the elbow are used to determine the anticipated size and fit of the components. The humeral bow and canal size are assessed on the lateral view. Both AP and lateral views are used to determine the size and angulation of the ulnar canal.

SETUP/PATIENT POSITIONING

Intravenous antibiotics are administered preoperatively. Anesthesia usually consists of a regional block with general anesthetic. We prefer the patient on a bean bag in the semi-supine (45-degree lateral) position with the operative arm topmost and draped over the chest. Care is taken regarding protection/padding and alignment of the patient’s head, spine, and limbs. Alternatively, supine or lateral positions may be used. In any case, skin preparation extends from the fingertips to the midline of the back and chest, the hand is covered with a sterile impervious drape (e.g., stocking), and the arm is draped free. A sterile tourniquet is placed about the upper arm.

SKIN INCISION

With uncommon exceptions resulting from a soft tissue condition, a longitudinal posterior skin incision is used. The skin incision is curved laterally around the olecranon, decreasing subsequent scar tenderness as the elbow often rests on the medial border of the olecranon. The incision is carried down through deep fascia overlying the triceps muscle proximally and down to the subcutaneous border of the ulna distally. Fascial–cutaneous flaps are raised medially and laterally, protecting the subcutaneous arterial plexus and the cutaneous nerves within the subcutaneous fat.

ULNAR NERVE TRANSPOSITION

Ulnar nerve transposition should be considered for all patients with preexisting ulnar neuropathy and in cases in which a medial exposure is used. Either a subcutaneous or a submuscular transposition can be performed. Submuscular transpositions require release and repair of the flexor–pronator origin. Subcutaneous transfers are often stabilized with a fascial sling. Careful inspection of the nerve prior to closure ensures that there is no impingement or kinking of the nerve.

TOTAL ELBOW ARTHROPLASTY USING THE COONRAD-MORREY PROSTHESIS

A deep incision is made following the medial border of the triceps, proceeding distally along the posterior bundle of the medial collateral ligament, incising the joint capsule, and continuing obliquely through the flexor carpi ulnaris fascia, across the subcutaneous border of the ulna and ending at the fascia of the extensor carpi ulnaris. The soft tissues, including the posterior capsule, are elevated from bone in a medial-to-lateral direction as a single flap. Keeping the elbow flexed 20 to 30 degrees facilitates the dissection. Because the fascia over the subcutaneous border of the ulna is quite thin, an osteotome may be used to elevate small cortical bone chips along with the fascia, reducing the risk of buttonholing. Laterally, the anconeus can be released proximally at the humerus and subperiosteally from the ulna and elevated as part of the soft tissue flap, exposing the radial head.

Releasing the anterior bundle of the medial collateral ligament from the humerus allows the elbow to dislocate.

Preoperative planning determines the implant sizes anticipated to best fit the patient. Any combination of the three humeral and ulnar implant sizes can be accommodated by the universal articulation. The humeral stem comes in three lengths—10, 15, and 20 cm—and in three diameters—extra small, small, and standard. The 10-cm length is recommended for rheumatoid arthritis, leaving the proximal humerus free to accommodate a shoulder arthroplasty component if necessary in the future. The 15-cm length is generally used for traumatic cases, whereas the 20-cm length is reserved for certain revision cases and other cases involving marked distal bone loss. The ulnar component also has three available diameters, and there is an extra-long component that is designed for use in revision cases.

Exposure is carried out by one of the techniques described previously. Dr. Bernard Morrey routinely uses the medial triceps-reflecting (Morrey) approach. The positioning of the arm during this description will assume that approach has been used.

After completing soft tissue exposure, the tip of the olecranon is removed with an oscillating saw. To adequately expose the distal humerus, the elbow is fully flexed and the forearm is rotated externally. During preparation of the distal humerus, the surgeon is mindful of protecting the medial and lateral columns. The midportion of the trochlea is removed using a rongeur or a saw.

The humeral canal is then entered through the roof of the olecranon fossa. This is usually accomplished with a burr, although a rongeur may suffice in soft bone. A long, twist reamer identifies the humeral canal and acts as an alignment stem. The handle is removed and is replaced with the distal humerus cutting block. The side arm, resting on the capitellum, determines appropriate height, and proper rotation is determined by aligning the flat of the cutting block with the plane of the posterior columns.

An oscillating saw is used to resect the trochlea, using the distal humerus cutting block as a guide. A pitfall to avoid is cutting too tightly on the cutting block, resulting in too narrow a trough so that the component places excessive forces on the medial or lateral columns or both, and cross-hatching at the junction of the columns and olecranon fossa, resulting in a stress-riser at the base of the column.

The cutting block and alignment stem are removed and the distal humerus is rasped with the appropriate-sized rasp for the anticipated stem. Short (4-inch) stems are preferred in patients with rheumatoid arthritis who may later require shoulder replacement surgery for shoulder pathology. The 6-inch stem is usually used for traumatic etiologies.

The soft tissue is elevated from the anterior cortex of the humerus to accommodate the anterior flange. The articulation of the trial humeral component is placed in the trochlear trough to ensure there has been adequate resection. If this is the case, the trial component is then seated within the humeral canal.

Attention is turned to the ulna. The ulnar canal is entered at the base of the coronoid using a high-speed burr elevated at a 45-degree angle to the olecranon. The direction of the ulnar canal is determined with a small awl, and a rongeur is used to create a trough in the olecranon in line with the awl. A pilot rasp is followed by the appropriately sized ulnar rasp. For final seating, a mallet is often required and care is taken to ensure appropriate rotation. The handle should be perpendicular to the flat posterior cortex of the olecranon. The trial ulnar component is then inserted. Appropriate depth of insertion will place the center of the prosthetic hinge at the center of curvature of the sigmoid notch.

A trial reduction is then carried out with the trial humeral and ulnar components in place. This ensures that reduction can be readily carried out and that the elbow range of motion is full, with no impingement or residual contracture. In some cases, the combination of a slight bow (concave anterior) of the humerus and a small canal will cause the humeral component to bind. In these cases, a large plate bender is used to create a slight bow (approximately 5 degrees) in the distal one third of the humeral component.

The trial components are removed, and both medullary canals are cleansed with pulse lavage and dried. It is safest to cement the implants separately. The narrow tube of the cement injection system is cut to the length of the ulnar component. The ulnar canal is then filled with cement to the depth of the ulnar component from distal to proximal. The ulnar component is then advanced into position.

A bone graft 2 cm by 2 cm with a thickness of 2 to 4 mm is shaped from the resected trochlear bone. A similar technique is then used to fill the humeral canal. If desired, a cancellous bone plug or cancellous chips from the trochlea can be used as a cement restrictor to prevent excessive proximal fill. The 2-cm by 2-cm bone graft is then placed against the anterior cortex of the distal humerus so that it will sit snuggly under the anterior flange (anterior to the anterior cortex of the humerus) once the humeral component is impacted into position. The humeral component is then inserted into the humeral canal to a depth that allows articulation with the ulnar component. The anterior flange should also be engaging the anterior bone graft. The ulnar and humeral components are then articulated and secured with the “pin-in-pin” axis system, and the humeral component is impacted into a fully seated position with the elbow positioned at 90 degrees. The depth of humeral insertion is determined by the depth at which the anterior flange engages the anterior cortex. This usually places the distal margin of the humeral component at or slightly proximal (1 to 2 mm) to the distal margin of the capitellum.

The tourniquet is deflated and hemostasis is obtained. The elbow is taken through a range of motion. An intraoperative range of motion of 0 to 140 degrees can usually be expected. The radial head is not routinely excised, but this can and should be done if dictated by the pathology.

The triceps mechanism is repaired to the ulna using no. 5 nonabsorbable suture through bone tunnels. The ulnar nerve transposition is completed.

The wound is closed in layers. Use of a drain is optional. The skin closure can be accomplished with staples in better-quality tissue, although a running 3.0 suture is often preferable in patients with rheumatoid arthritis with thinner dermal tissue. The most significant complication of the medial triceps reflecting exposure is triceps detachment/rupture.