Preoperative Evaluation
The preoperative evaluation should focus on the assessment of contracture and deformity, identifying occult infection, understanding the anticipated physical demands of the patient, and providing counseling about alternative procedures and limitations after surgery. The potential for soft-tissue complications should be addressed, especially when the patient has an open injury or has had a previous surgical procedure. Preoperatively, we routinely measure the erythrocyte sedimentation rate and C-reactive protein level and aspirate the joint and/or the nonunion site for fluid to send for culture if a patient has had previous surgery or has another risk factor for deep infection.
Radiographs help to identify hardware to be removed; estimate the amount of bone loss that will be present after resection of the ununited fragments; and assess the size and shape of the humeral and ulnar canals in order to anticipate the need for smaller, or intraoperative contouring of, prosthetic stems. Associated nonunion of the olecranon requires special attention at the time of surgery. Static deformity should be taken into consideration (Figs. 1-A and 1-B): failure to balance the soft tissues may result in accelerated polyethylene wear in patients with long-standing malalignment. Additional imaging studies such as computed tomography scans are seldom required unless the decision to fix or replace will be made intraoperatively. However, computed tomography scans with three-dimensional reconstructions may be helpful for patients with severe deformity.
Patient Position and Exposure
The patient is placed supine on the operating table with the involved upper extremity supported over a bolster and across the chest (Fig. 2). A non-sterile pneumatic tourniquet is employed. A straight midline posterior skin incision is made, centered just medial to the tip of the olecranon and extending proximally and distally for about 10 cm. Full-thickness medial and lateral skin flaps are carefully elevated.
The ulnar nerve may have been translocated during previous operations. In patients with no preoperative ulnar nerve symptoms, a translocated ulnar nerve needs to be identified and protected but does not need to be fully dissected. When the patient has ulnar nerve symptoms or the ulnar nerve is still in its anatomic location, a formal ulnar nerve dissection, neurolysis, and subcutaneous transposition are performed. The ulnar nerve is most easily identified proximally and dissected from proximal to distal to the first motor branch, with efforts made to preserve its vascularity. A vessel-loop placed around the nerve helps to mobilize and protect it; we do not attach metallic instruments to the vessel-loop to avoid constant tension on the nerve. The medial intermuscular septum is resected, the flexor carpi ulnaris is divided, and the nerve is translocated into an ample anteromedial subcutaneous pocket.
Access is gained to the posterior aspect of the humeral diaphysis, and a retractor may be used to place the triceps under some tension and expose the posterior articular compartment. Next, the flexor-pronator origin is sharply released from the medial epicondylar fragment (Fig. 3). All medial fragments are then removed by releasing their soft-tissue attachments, including the anterior and posterior aspects of the capsule (Figs. 4-A and 4-B); hardware previously placed in this region is removed as well. Attention is then turned to the lateral side of the joint. The lateral epicondyle is identified, and the common extensor origin is sharply released, which allows removal of the remaining lateral fragments and any hardware present at that location (Fig. 5). Additional exposure may be needed to remove any remaining hardware and the thickened and contracted anterior aspect of the elbow capsule. With all of the ununited fragments removed, the distal part of the humeral shaft may be "delivered" adjacent to the medial or lateral aspect of the triceps (Figs. 6-A and 6-B). The ulnar nerve should be protected from inadvertent tension during the rest of the procedure.
Bone Preparation
The humeral preparation is straightforward. Typically, no bone cuts are needed in the absence of the condyles. The canal is simply prepared by rasping to the appropriate size. Care should be taken to seat each rasp in the correct rotational orientation.
The inability to fully seat a rasp may be due to a narrow entrance to the canal, residual distal bone, or a tight or bowed midpart of the shaft, which will require slight bending of the humeral stem. A 15-cm (6-in) long humeral stem is used in most cases; a shorter, 10-cm (4-in) stem is uncommonly selected for patients who have had, or may later require, shoulder arthroplasty. The anterior cortex of the distal humeral shaft is exposed and is roughened with an osteotome to promote healing to the autograft, which will be prepared from the resected fragments and placed behind the flange of the humeral component.
A trial prosthesis is then used to judge the position of the humeral component, including rotation, which is established by the plane of the medial condylar flare or, for more proximal nonunions, by the intermuscular septum. In patients with a distal nonunion and no major contractures, the depth of insertion of the humeral component is defined by the flange of the implant resting on the roof of the coronoid fossa. The implant may need to be seated proud in the presence of severe bone loss or deep in the presence of severe contracture to allow full extension of the elbow joint with the prosthesis in place. An axial load applied to the forearm helps the surgeon to estimate the proper depth of insertion of the humeral component by placing tension on the anterior and posterior soft-tissue structures (Fig. 7).
Exposure and preparation of the ulna are the most challenging portions of the procedure. This step is best performed from the medial side. Approximately 20% to 25% of the triceps tendon attachment is released from the olecranon, allowing the medial margin of the triceps to be reflected (Fig. 8). Flexion and rotation of the forearm exposes the proximal part of the ulna. The tip of the olecranon is removed to provide unobstructed access to the medullary canal. A high-speed burr is then employed to enter the ulnar canal at the base of the coronoid (Fig. 9). The burr is oriented toward the subcutaneous border of the ulna, which is identified between the index finger and thumb of the surgeon's other hand. The canal is then prepared serially with rasps. Care is taken to avoid perforation of the cortex. Proper rotational orientation of each ulnar rasp is confirmed by keeping the handle perpendicular to the flat dorsal aspect of the olecranon9 (Fig. 10). A trial reduction of the humeral and ulnar components is carried out, and the maneuver by which the elbow can be reduced and the components articulated is tested.
Component Implantation
After the canals have been lavaged and dried, 2 g of van-comycin is mixed with 80 g of polymethylmethacrylate, which is vacuum-mixed and placed in an injection gun. The canals are plugged with either bone or commercially available cement restrictors. We prefer to inject the cement on the humeral side first (Fig. 11). The ulnar component is inserted to a depth midway between the olecranon and the coronoid (Fig. 12). A 3-mm-thick disk of autogenous bone fashioned from the resected fragments (usually from the trochlea) is placed at the anterior aspect of the humeral shaft so that it rests behind the flange of the humeral component, the stem of which is inserted down the humerus and tapped into place (Figs. 13-A and 13-B). Once the cement has set, the joint is reduced and the implants are linked with the "pin-within-a-pin" articulation (Figs. 14-A and 14-B). It should be noted that, unlike in the setting of primary total elbow arthroplasty, the absence of the condyles allows final articulation of the humeral and ulnar components after cementation and seating of the humeral component.
Closure
Prior to closure, the range of motion is checked. Ideally, there should be full extension and >140° of flexion, but less motion may be attainable in patients with a long-standing nonunion. If motion is limited, any sources of impingement should be identified and removed. The common flexor and extensor origins are then meticulously repaired to the medial and lateral aspects of the triceps, respectively, in an attempt to seal the joint (Fig. 15). The ulnar nerve is brought anteriorly and is secured in the subcutaneous medial pocket with a single absorbable suture in the subcutaneous flaps. The rest of the closure is routine. Use of a drain is optional.
After surgery, the elbow is placed in extension and a compressive dressing and anterior plaster splint are applied. The elbow is kept elevated for the first twenty-four to forty-eight hours, and active-assisted range-of-motion exercises are initiated on removal of the extension splint. Patients are allowed to perform activities of daily living as tolerated but are advised to avoid strenuous use of the upper extremity (Figs. 16-A and 16-B). We recommend that patients not lift objects heavier than 1 to 2 lb (0.45 to 0.9 kg) on a repetitive basis or heavier than 10 lb (4.5 kg) as a single event.
INDICATIONS:
Total elbow arthroplasty is considered for the salvage of an upper extremity with a distal humeral nonunion under the following circumstances.Elderly patient with low anticipated physical demandsA distal nonunion associated with severely compromised distal bone stockPrevious associated inflammatory or degenerative articular changes
Elderly patient with low anticipated physical demands
A distal nonunion associated with severely compromised distal bone stock
Previous associated inflammatory or degenerative articular changes
CONTRAINDICATIONS:Infected nonunionActive individual who anticipates high physical demandsNonunion amenable to stable internal fixationSevere neurological deficiency
Infected nonunion
Active individual who anticipates high physical demands
Nonunion amenable to stable internal fixation
Severe neurological deficiency
PITFALLS:Undiagnosed infection. Failure to identify an infection prior to elbow arthroplasty may lead to deep infection after the surgery. Every effort should be made to rule out infection prior to arthroplasty, including needle aspiration in patients who have previously undergone surgery or who have another risk factor. Antibiotic-loaded cement is routinely used. In the event of known infection after previous internal fixation, the arthroplasty is staged, with a first procedure to remove all hardware and débride the nonunion followed by delayed implantation of the components as a second stage.Ulnar nerve. Persistent ulnar nerve symptoms may be a source of patient dissatisfaction after an otherwise successful elbow arthroplasty. Every effort should be made to protect the ulnar nerve during surgery, and we recommend routine anterior subcutaneous transposition of the nerve.Ulnar preparation. Access to the ulna is more difficult with a so-called triceps-on approach. Detachment of the medial 20% to 25% of the triceps from the olecranon facilitates this portion of the procedure.Component malposition. Rotation of the humeral component may be difficult to judge. The anterior flange should be parallel to the anterior cortex, and the flat posterior portion of the yoke should be parallel to the posterior cortex of the humerus. Rotational alignment of the ulnar component is based on the flat dorsal aspect of the olecranon. The depth of component insertion is based on an intraoperative assessment of soft-tissue tension and the motion necessary to achieve full elbow extension.Cementing technique. Cement should be delivered early enough to allow adequate filling of the relatively narrow canals. If the cement is too runny, it will extend excessively into the canals; this can be prevented with cement restrictors.Stiffness and intraoperative motion. Articular stiffness is a central pathological element of distal humeral nonunions. A formal anterior capsulectomy is recommended in patients with a long-standing nonunion. Additional extension may be gained by deeper seating of the humeral component. Care should be taken to avoid impingement in flexion, as it may lead to loosening of the ulnar component.Soft-tissue balance. Long-standing nonunions may be complicated by asymmetric soft-tissue contractures and shortening. Extensive releases may be required in order to avoid edge-loading of the polyethylene and accelerated wear. Patients with severe shortening are at risk for nerve injuries and compartment syndrome, especially when aggressive soft-tissue releases are required.Prosthetic articulation. A sufficient amount of soft tissue must be released to allow adequate mobilization of the ulna with respect to the humerus to permit prosthetic articulation.Postoperative protection. Patients should understand the need for lifetime protection of the implant against strenuous activities. As a general rule, we recommend avoidance of lifting weights heavier than 10 lb (4.5 kg) with use of just the operatively treated upper extremity and avoidance of repetitive lifting of weights heavier than 1 to 2 lb (0.45 to 0.9 kg).
Undiagnosed infection. Failure to identify an infection prior to elbow arthroplasty may lead to deep infection after the surgery. Every effort should be made to rule out infection prior to arthroplasty, including needle aspiration in patients who have previously undergone surgery or who have another risk factor. Antibiotic-loaded cement is routinely used. In the event of known infection after previous internal fixation, the arthroplasty is staged, with a first procedure to remove all hardware and débride the nonunion followed by delayed implantation of the components as a second stage.
Ulnar nerve. Persistent ulnar nerve symptoms may be a source of patient dissatisfaction after an otherwise successful elbow arthroplasty. Every effort should be made to protect the ulnar nerve during surgery, and we recommend routine anterior subcutaneous transposition of the nerve.
Ulnar preparation. Access to the ulna is more difficult with a so-called triceps-on approach. Detachment of the medial 20% to 25% of the triceps from the olecranon facilitates this portion of the procedure.
Component malposition. Rotation of the humeral component may be difficult to judge. The anterior flange should be parallel to the anterior cortex, and the flat posterior portion of the yoke should be parallel to the posterior cortex of the humerus. Rotational alignment of the ulnar component is based on the flat dorsal aspect of the olecranon. The depth of component insertion is based on an intraoperative assessment of soft-tissue tension and the motion necessary to achieve full elbow extension.
Cementing technique. Cement should be delivered early enough to allow adequate filling of the relatively narrow canals. If the cement is too runny, it will extend excessively into the canals; this can be prevented with cement restrictors.
Stiffness and intraoperative motion. Articular stiffness is a central pathological element of distal humeral nonunions. A formal anterior capsulectomy is recommended in patients with a long-standing nonunion. Additional extension may be gained by deeper seating of the humeral component. Care should be taken to avoid impingement in flexion, as it may lead to loosening of the ulnar component.
Soft-tissue balance. Long-standing nonunions may be complicated by asymmetric soft-tissue contractures and shortening. Extensive releases may be required in order to avoid edge-loading of the polyethylene and accelerated wear. Patients with severe shortening are at risk for nerve injuries and compartment syndrome, especially when aggressive soft-tissue releases are required.
Prosthetic articulation. A sufficient amount of soft tissue must be released to allow adequate mobilization of the ulna with respect to the humerus to permit prosthetic articulation.
Postoperative protection. Patients should understand the need for lifetime protection of the implant against strenuous activities. As a general rule, we recommend avoidance of lifting weights heavier than 10 lb (4.5 kg) with use of just the operatively treated upper extremity and avoidance of repetitive lifting of weights heavier than 1 to 2 lb (0.45 to 0.9 kg).
AUTHOR UPDATE:
There have been no changes in the surgical technique since the time of publication of the original paper.