Rick F. Papandrea
Total elbow arthroplasty has evolved into a reliable treatment for the appropriately selected patient. The advent of reliable devices in the 1980s allowed this joint to be replaced with outcomes similar to other joints. Not that total elbow arthroplasty is without its potential complications or problems. At least as important as in other joints, if not more important because of potential pitfalls, proper surgical technique is paramount for a successful arthroplasty.
Implant Types
The type of implant used can dictate the surgical approach and various technical details; although much about total elbow arthroplasty surgical technique is not implant design specific. Current devices are most easily categorized as being either linked or unlinked. Constraint of the implant is important, but is not dependent on linkage. A linked implant is best thought of as a hinge, with the ulnar and humeral components coupled, or linked. Initial designs had no play or toggle between the components, and these devices failed quickly. Modern-design linked implants allow for angular and rotational play between the humeral and ulnar components. Unlinked components have no direct connection between the components. The amount of congruity or conformity between the articulating surfaces of the implants dictates the constraint of the device. A highly congruent articulation has more constraint than an articulation with little conformity. Thus, a linked or unlinked device can be either constrained or unconstrained. An unlinked device with little constraint has the highest risk of dislocation; particular attention has to be given to both pre-existing deformity and adequate soft tissue repair, especially the ligaments. A linked device cannot, by design, dislocate; but, attention to pre-existing deformity is just as important as when considering an unlinked design.
Surgical Indications and Contraindications
The disease-specific indications and contraindications will be discussed in the following chapters. General indications for a total elbow arthroplasty include a painful elbow joint that does not have less-extensive reconstructive options available. Adequate bone stock for reconstruction with the chosen prosthesis is necessary, and the surgeon should have familiarity with the technical limitations of the prosthesis considered for implantation. Bone deficit can be compensated for by some devices, but each device has limitations. Custom devices are rarely if ever needed. A functional elbow flexor is necessary. A competent extensor mechanism is considered important; but, a functional limb can be reconstructed without, if the patient is willing to accept a compromise. Gravity is then used for elbow extension, and overhead function with the involved limb is not possible. An adequate soft tissue envelope is necessary, especially with the higher risk of infection in total elbow arthroplasty. Understanding of and compliance with the restrictions inherent to any total elbow arthroplasty is a mandatory requisite for surgery. Longevity of newer implants has improved to parallel hip arthroplasty in rheumatoid patients. Failures have been noted in patients placing high demands on their reconstructed joint. Because of this, most surgeons have placed the permanent restriction on their patients of not lifting >10 pounds as a single, occasional event, and 1 to 2 pounds as a repetitive event.
Contraindications for total elbow arthroplasty include noncompliant patients, inadequate bone stock or soft tissue
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envelope, active or recent infection, or a dysfunctional elbow flexor.
Surgical Approach
As discussed in the preceding chapter, there are several approaches to the elbow, but a posterior incision allows for much freedom in the deeper exposure. Although a laterally based skin incision (and deeper exposure) has been used in elbow arthroplasty (especially some unlinked designs), it does have inherent limitations. This author routinely uses a universal posterior skin incision for elbow arthroplasty. Multiple approaches can be easily accomplished, and future revision surgery is not compromised by other skin incisions. Fewer problems with the cutaneous nerves are encountered when the incision is placed posteriorly. Many elbows requiring arthroplasty have pre-existing deformity, which can be challenging to correct. Laterally based approaches can make a challenging deformity nearly impossible to correct.
When planning the surgical approach to elbow arthroplasty, there are three structures that require consideration regardless of the implant used. These include the triceps, the ulnar nerve, and the collateral ligaments. The implant used may dictate certain needs, but each of these three factors must be considered in every elbow arthroplasty.
Triceps
Recent attention has focused on the potential complications with triceps reattachment after elbow arthroplasty. Postoperative weakness has been attributed to failure of the repair site of triceps to the olecranon. This has caused a scrutiny of current techniques and reconsideration of alternative methods to deal with the triceps. Most available implants for elbow arthroplasty recommend that the triceps be released or transected at some level. The ideal method of release is unknown. Although more challenging, implants can be placed through a medial and/or lateral deep exposure. The triceps can then be left alone. Visualization is more difficult and extreme care must be taken to ensure proper implant orientation.
One exception to the requirement for triceps release occurs when treating chronic nonunions with a linked prosthesis. As described by Morrey, these are readily approached by excising the distal humeral fragment(s). The epicondyles are, by default, excised, but this does not compromise the result. By excising the distal humerus, the triceps can be left attached to the olecranon and the components can be implanted through the gap from the resection. This has the advantage of allowing full triceps activity without the need to protect a repair. If surgical exposure is adequate from this approach, the risk of extensor weakness should be eliminated. The potential drawback of the approach is the limitation of exposure and the potential inability to correct significant deformity. A similar technique has also been described for routine elbow linked arthroplasty by Matsen.
When the triceps is dealt with directly, the tendon needs to be released from the olecranon is some fashion. Early techniques (Campbell/Van Gorder) involved leaving a tongue of triceps tendon attached to the olecranon, detaching the tendon proximally in a “V” fashion. This did allow for a V-Y lengthening if needed and also did not disturb the Sharpey fibers attachment of the triceps. This approach has been essentially abandoned for modern elbow arthroplasty, but as concern regarding the healing potential of the triceps to the olecranon is raised, it could once again be considered.
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Figure 58-1 The Bryan-Morrey, or Mayo, approach reflects the triceps with the anconeus laterally. The distal extent continues to the extensor musculature and fascia of the forearm, which is kept in continuity with the triceps. |
The Bryan-Morrey, or Mayo, approach to the triceps is a reflection of the triceps laterally off of the olecranon. The anconeus is kept in continuity with the triceps, and the whole sleeve of tissue, with the extensor fascia, is reflected laterally (Fig. 58-1).
The triceps is repaired to the olecranon using bone tunnels to pass sutures. This technique allows for complete separation of the olecranon from the triceps. If the reattachment does not heal completely, there will be at minimum triceps weakness and possibly complete extensor mechanism failure. The tissue distal to the Sharpey fibers can be quite atrophic, resulting in a defect of the sleeve of soft tissue. This approach can also be performed leaving a small wafer of bone on the triceps to allow for precise attachment back to the olecranon and also allow for bone-to-bone healing of the extensor mechanism. Unfortunately, in clinical practice, this addition did not bear out any advantage to the all–soft tissue approach.
Another approach to dealing with the triceps and allowing for the potential of bone-to-bone healing is the Gschwend approach (Fig. 58-2). This is a midline triceps splitting approach. As the distal dissection is undertaken, the split continues along the subcutaneous border of the
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ulna. As originally described, an osteotome is then used to remove the medial and lateral cortex of the ulna with the soft tissue attachments. The collateral ligaments can be left in situ, but releasing them allows for significantly more exposure. The split and the bone wafers are reattached through drill holes at closure. This approach can be done strictly as a soft tissue exposure by carrying the dissection along the medial and lateral ulna, forgoing any bone resection.
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Figure 58-2 The Gschwend approach splits the triceps and continues distally, osteotomizing triceps attachment with bone from the olecranon. |
Ulnar Nerve
Prior to undertaking any elbow arthroplasty, the status of the ulnar nerve should be documented. If there has been previous surgery, attempts should be made to study the old operative records. In cases of old trauma or surgery, one should never assume the location of the ulnar nerve. It must be identified and protected throughout the procedure. The proximal medial triceps border is usually a reliable location to identify the nerve in an elbow with previous surgery.
Transposition of the nerve into a subcutaneous pocket is standard practice by many surgeons regularly performing elbow arthroplasty. The nerve can be safely removed from the primary surgical field and should not cause further difficulty in the future, should a revision be needed. Although there is always risk when transposing the ulnar nerve, the risk is far less than that incurred by leaving it in the cubital tunnel. A transposition was not originally described by Gschwend in his triceps splitting approach. At a minimum the nerve needs to be identified in this technique and can be readily transposed with little additional effort.
Collateral Ligaments
The lateral collateral ligament must be released to allow dislocation or subluxation of the elbow sufficient to allow for implantation of any total elbow device. Releasing the medial collateral ligament will allow for better correction of any pre-existing deformity and give better access. If the device implanted is linked, neither ligament needs to be repaired.
If an unlinked device is used, the lateral collateral must be repaired or reconstructed. Although a medial collateral ligament–deficient elbow may not dislocate in the native state, the increased instability will jeopardize an unlinked implant, and consideration should be given to repair or reconstruction.
Bone Preparation
Humerus
Each different elbow arthroplasty system has its own cutting blocks and guides. However, there are some general principles for humeral preparation. The posterior aspect of the capitellum is the origin for the anconeus. The muscle should be dissected off of this area to allow for complete exposure of the lateral column.
Care needs to be taken when cutting out the trochlea for the humeral component. Although consisting of cortical bone, the columns are narrow, and if notched or too generous a cut is made, the column may fracture, separating the epicondyle from the humerus. If this occurs, the most efficacious treatment is to excise the fractured fragment if a linked implant is being placed. The loss of the epicondyle and associated collateral will not have bearing on the outcome. Attempts at fixation of these small fragments have little to no net benefit. If the device is unlinked, this fracture will have significant bearing on the potential stability. Either the fragment has to be fixed or a linked device has to be used. If an unlinked device is used, fixation can be done with a tension band and wires, or if the fragment is large, a unicortical plate.
The humeral canal narrows to a point in the sagittal plane. Because of this, if the starting hole is not proximal enough, or attention is not paid to the opening, there may be remnant cortical bone tapering inward. This obscures the true diameter of the humeral canal, and more important, can cause the humeral instrumentation or implant to be pushed anterior or posterior. It is imperative to recognize this, and if the canal is not accepting the rasps or trials, to ensure that a sufficient amount of the distal humerus is removed to allow a straight approach up the medullary canal. If it is apparent that there is impeding bone, it is often easiest to remove with a rongeur.
Ulna
Most implants require that the tip of the olecranon is excised to allow for instrumentation of the medullary canal and implantation of the device. The attachment site for the triceps must be retained. Like the humerus, the opening
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to the medullary canal may not initially allow for correct broaching or rasping. This is especially true in patients with osteoarthritis and/or dense bone. When the subchondral bone is too dense, using a burr to open the canal will save time and prevent potential catastrophic fracture of the proximal ulna.
Implantation
Each total elbow arthroplasty device has a specific technique for implantation. However, some universal concepts are worthy of consideration.
Linked implants can often be implanted separately, then linked, or implanted all at once already linked. The advantage of implanting each component separately is the ability to focus technique on each side individually. The disadvantage is that of having to mix two separate batches of cement and the extra time it takes for the two sides to cure sequentially. The advantages of separate component implantation far outweigh the disadvantages for the surgeon with limited experience implanting total elbows. Linked implantation should be done only by surgeons with high-volume experience.
Humerus
The trefoil shape of the humerus, as well as the guides for most systems, help with proper rotational alignment. The anterior flange on many humeral components also aids in rotational alignment. The flange's main purpose is to resist posterior and rotationally directed forces on the humeral component. These stresses are significant and can lead to early failure if not neutralized. For this reason, the flange should be grafted if the technique calls for it. Evidence of the stress on the flange is noted postoperatively, when most of these grafts heal and many hypertrophy.
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Figure 58-3 Plain radiographs of a balanced (A)and unbalanced (B) linked total elbow arthroplasty. |
Ulna
Rotational alignment can be more difficult to account for in the ulnar component. Once the medullary canal is prepared, it is cylindrical, allowing for rotation of the component. Some devices account for this and have flanges or flat posterior aspects of the component. Even with these additions, if one is not careful, the rasps and trials (and eventually the final components) can be placed with rotation. This will cause undue stress on the coupling in a linked component and potential for dislocation in an unlinked device. There are two reliable methods to ensure proper rotational alignment of the ulnar component. As described by King, the flat spot on the dorsal ulna is almost perfectly perpendicular to the plane of the greater sigmoid notch. O'Driscoll has recently described the use of the radial head (or shaft if the head has been resected) to align the ulnar component. The ulnar component must be aligned so that the flexion axis of the device passes through the radial head (or shaft) center when viewing from end on.
Every effort should be made to balance the elbow while using the trial implants. This is especially true in elbows with significant pre-existing deformity. Unlinked devices have a high dislocation rate. Unbalanced devices that are
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not linked are even more likely to dislocate. A linked device will not dislocate, but if unbalanced, will load the bearings more than will a balanced elbow (Fig. 58-3). This has been proposed as a cause of early failure.
Closure
Details of the triceps repair depend on the type of approach that was used. Every effort should be made to reattach the triceps to its native location. Marking the area of the Sharpey fibers attachment with a suture can ensure later reattachment to the proper location. If the triceps was detached only as soft tissue, drill holes should be used for suture passage of no. 2 or no. 5 nonabsorbable sutures to secure the repair. One can usually pass straight needles directly through the ulna with a pin driver, obviating the need to drill, and then pass the sutures with another device.
If the ligaments were taken down, which is usually necessary for adequate exposure, they need not be repaired in the case of a linked device. If the device implanted is unlinked, stability must be restored or else the chance of dislocation is high. The ligaments should be repaired, or if this is not possible, reconstructed.
Seroma formation is not uncommon postoperatively, owing to the skin flaps created during dissection. To decrease the likelihood or severity of this, the subcutaneous tissue can be tacked down to the fascia to close this potential space. When doing this, the cutaneous nerves must be avoided to prevent neuromas.
Since most patients have trouble obtaining extension postoperatively, splinting in full extension is helpful. This allows a compressive bandage to be applied, and the elbow can then be elevated or hung in a stockinette to decrease swelling.
Suggested Readings
Bryan RS, Morrey BF. Extensive posterior exposure of the elbow. a triceps-sparing approach. Clin Orthop. 1982;166:188–192.
Duggal N, Dunning CE, Johnson JA, et al. The flat spot of the proximal ulna: a useful anatomic landmark in total elbow arthroplasty. J Shoulder Elbow Surg. 2004;13:206–207.
Gill DR, Morrey BF. The Coonrad-Morrey total elbow arthroplasty in patients who have rheumatoid arthritis. A ten to fifteen-year follow-up study. J Bone Joint Surg Am. 1988;80:1327–1335.
King G. J, Itoi E, Niebur GL, et al. Motion and laxity of the capitellocondylar total elbow prosthesis. J Bone Joint Surg Am. 1994;76:1000–1008.
Ring D, Kocher M, Koris M, et al. Revision of unstable capitellocondylar (unlinked) total elbow replacement. J Bone Joint Surg Am. 2005;87:1075–1079.
Schuind F, O'Driscoll S, Korinek S, et al. Loose-hinge total elbow arthroplasty. An experimental study of the effects of implant alignment on three-dimensional elbow kinematics. J Arthroplasty. 1995;10:670–678.
Wright TW, Hastings H. Total elbow arthroplasty failure due to overuse, C-ring failure, and/or bushing wear. J Shoulder Elbow Surg. 2005;14:65–72.