Indications for Elbow Arthroplasty
The elbow is a necessary joint for normal functioning in daily life, yet it is susceptible to various degenerative conditions and traumatic lesions or posttraumatic sequelae. In contrast to other joints, such as the hip or knee, elbow function cannot be easily replaced or bypassed by external aids.[1] In the past, multiple solutions have been used to solve the problem of painful, stiff, or flail elbows.[2]
The elbow joint combines two rotatory axes using three joints: flexion/extension by the humeroulnar and humeroradial joints, and pronation/supination by the radioulnar and humeroradial joints.
Osseous stability depends on the degree of flexion of the elbow.[3] In complete extension, the boney prominence on the upper end of the ulna, the olecranon, ensures stability by docking into the olecranon fossa. At approximately 30° of flexion, the elbow has the least osseous stability.[3] In maximal flexion, the coronoid process engages in the coronoid notch and accounts for stability.[3] In addition to providing osseous stability, collateral ligaments aid in varus/valgus stability during flexion and extension, especially where osseous stability is lacking.[3]
When elbow function for adequate performance of activities of daily life is compromised, elbow arthroplasty may be a good option, especially in the low-demand elderly patient. Today, the most frequent indications for the procedure are to treat the sequelae of long-standing, degenerative disease—ie, rheumatoid arthritis, which accounts for 25% of total elbow arthroplasties, and posttraumatic conditions, which account for 62%.[4,5,6] Secondary osteoarthritis, accounting for 7% of elbow arthroplasties, is more common than primary osteoarthritis of the elbow.[5,6] In recent decades, indications for elbow arthroplasty have shifted from rheumatoid arthritis toward trauma, as improved disease-modifying antirheumatic drugs have become available.[6]
The use of elbow arthroplasty for primary management of comminuted elbow fractures is rising, because the procedure produces better long-term results than several decades ago.[6] Elbow arthroplasty can be an option in oncologic surgery when resection of primary or secondary cancer is necessary.[7]
Depending on the exact location of the elbow-related problem, various options are available as treatment (Table).
Table. Treatment Options for Elbow-Related Problems
| Affected joint(s) | Options | Plain radiographs |
|---|---|---|
| Radial head | Radial head replacement | Figure 1 |
| Ulna | Total elbow arthroplasty | Figure 2 |
| Humeroradial | Radial head replacement | Figure 1 |
| Unicompartmental replacement | Figure 3 | |
| Humeroulnar | Total elbow arthroplasty | Figure 2 |
| Humerus | Hemiarthroplasty | Figure 4 |
| Radioulnar | Radial head replacement | Figure 1 |
| Radial head resection |
Figure 1. Radial head replacement.
Figure 2. Total elbow arthroplasty.
Figure 3. Unicompartmental replacement.
Figure 4. Hemiarthroplasty
Absolute contraindications include general orthopedic issues, such as active infection (local or systemic), inability to undergo general anesthesia, paralysis of the arm, and inadequate postoperative soft-tissue coverage.
Relative contraindications include young age, because younger patients tend to put high-demand stress on the elbow joint by participating in sports and other activities, and diabetes and smoking, because either of these conditions might compromise wound healing. In addition, walking with crutches during rehabilitation may be problematic for patients who have had elbow arthroplasty.
Furthermore, possible implant-specific long-term complications influence decision-making on the part of the surgeon. Radial head prostheses may lead to excessive wear of and pain in the capitellum.[8] Hemiarthroplasty does not replace the ulna and radius, which may lead to painful degeneration of these native articulating surfaces.[9] Unicompartmental arthroplasty relieves only pronation/supination problems, and has only a slight effect on flexion/extension.
In total elbow arthroplasty, two main models are currently available: linked and unlinked designs. Linked (or semi-) constrained elbows have a mechanical connection between the humeral and ulnar components that prevents disassociation. These implants do not rely on muscular or ligamentous tissues for stability.
Unlinked implants have no physical connection between the humeral and ulnar components. They rely on bearing surface architecture as well as soft-tissue integrity for elbow stability.[10]
Unlinked total elbow arthroplasty consists of two separate implants and relies more on ligamentous stability, as opposed to linked arthroplasties, which have more intrinsic stability. This difference implies that unlinked arthroplasties are less suitable in patients with severe ligamentous instability, as seen in long-standing rheumatoid arthritis, because of a high dislocation rate.[11] In these cases, the use of linked designs is advisable.
In one modern design—the latitude total elbow arthroplasty—it is possible to decide during surgery whether to use a linked or unlinked version of the implant because this prosthesis offers an optional part for constrainment of the hinge.[12]
The inherent stability of the linked designs may result in higher forces being transferred across the implant/cement and cement/bone interfaces. This is why modern designs use a "sloppy" hinge, having 7°-10°0 varus/valgus inherent laxity at the hinge section, with a minimal motion-bearing contact area; this aims to maintain intrinsic stability without the risk for early loosening.
The fixation technique may be cemented or uncemented, with a bone-ingrowth coating. Cemented designs have the advantage of instant fixation, which might be favorable in the linked designs regarding the previously mentioned pulling-out forces. However, a long cement mantle may result in elaborate surgery if revision is necessary.
Medscape Orthopedics © 2016 WebMD, LLC
Any views expressed above are the author's own and do not necessarily reflect the views of WebMD or Medscape.
Cite this: Total Elbow Arthroplasty: The State of Clinical Practice - Medscape - Apr 07, 2016.
Comments