The elbow is an unforgiving joint that presents many challenges to the orthopaedic surgeon. When limited motion and painful arthrosis are present within the proximal ulnohumeral and radiocapitellar joint in the young active patient population, biological interposition arthroplasty of the elbow is a useful option for the treating orthopedist. It has been shown that painful loss of motion of the elbow after trauma, burns, or coma may cause severe impairment of function. As a nonprosthetic alternative, this method of treatment in younger patients has been successful and avoids the permanent lifting restrictions of arthroplasty. Biological interposition arthroplasty of the elbow using Achilles allograft in conjunction with an external fixator device and cutis interposition will be discussed. The distraction provided by the external fixator allows immediate passive movement while at the same time protecting the newly interposed biological tissue and soft tissue reconstruction.
HISTORY/INTRODUCTION
The elbow has two main functions: positioning the hand in space and stabilizing the upper extremity for power and fine motor activities. The clinical consequences of progressive arthritis result in a cycle of pain and stiffness that cause functional impairment and disability. The loss of flexion is more limiting because a loss of extension can be compensated by moving closer to an object. Three primary patterns of arthritis that involve the elbow consist of rheumatoid arthritis (inflammatory), posttraumatic arthritis, and primary osteoarthritis.
Rheumatoid arthritis is the most frequent form of arthritis in the elbow. Most of the cases are bilateral. Patients with rheumatoid arthritis have elbow involvement about 20% to 50% of the time. Women are affected more than men. The prolonged inflammatory process and synovitis lead to secondary changes, which consist of fixed joint contracture, ligamentous attenuation, annular ligament incompetence leading to subluxation of the radial head, and subchondral cyst formation. The cyst formation can lead to subarticular fractures.
Posttraumatic arthritis of the elbow is the second most prevalent arthritis. It commonly affects young and middle-aged individuals. The elbow joint is noticeably intolerant to trauma with a striking tendency for stiffness and arthritic changes. Biological interposition should be considered when, as a result of trauma, there is a painful limited arc of motion and articular damage in this patient population.
Primary osteoarthritis of the elbow is characterized by painful stiffness, mechanical symptoms, and the presence of hypertrophic osteophytes. Preservation of the ulnohumeral and radiocapitellar joint space is frequent. Preservation of the articular surfaces may account for the good results that are usually achieved with nonoperative treatment and nonprosthetic arthroplasty. Elbow osteoarthritis typically affects middle-aged men who engage in strenuous repetitive manual activities. Open or arthroscopic capsular release and removal of impinging osteophytes are the primary surgical treatment options. The relative sparing of joint cartilage makes elbow osteoarthritis unique in this regard. Arthroplasty is rarely indicated for primary osteoarthritis of the elbow and should be reserved for elderly individuals with low demands and for whom other treatment options have failed. In cases where arthroscopic procedures have failed, where there is underlying ankylosis with altered articular elbow anatomy, and when total elbow arthroplasty would not be an ideal treatment alternative, interposition arthroplasty with a biological graft combined with distraction arthroplasty is a viable treatment option. This scenario is especially indicated in the young and active middle-aged adult.
Elbow arthritis (inflammatory, traumatic, or primary type) may be surgically treated with biological interposition arthroplasty. The term interposition means that new tissue is placed between the damaged surfaces of the elbow joint. It involves debridement and “resurfacing” of the elbow joint articulation with a layer of biological tissue. In this surgery, tissue is taken from another source to fill in the space in the elbow joint. The soft tissue forms a false joint. This surgery has best results in younger people with healthy tissue supporting the elbow joint.
Biological interposition arthroplasty has been used as a reconstructive tool in the arthritic ankylosed joint for quite some time. Resection arthroplasty was first described as a form of treatment for inactive tuberculosis arthrosis. Biological interposition combined with resection arthroplasty had been a treatment of the ankylosed hip and knee in early literature. Data demonstrated promising results specifically for the elbow on both rheumatoid and traumatic conditions. Functional arthroplasty was initially described with the concept of converting the elbow into a simple ginglymus joint using autologous fat as the interposed tissue with postoperative treatment consisting of extension casting. The restoration of function by preserving collateral ligaments, while at the same time reducing the bone contact, allowed a functional adaptation of the newly formed joint.
During the past decades, biological interposition of the elbow has been redefined by pioneers such as Bernard F. Morrey, MD. Various biological and nonbiological tissues including muscle flaps, pig bladder, fat, fascia, dermis, allograft dermis, and silicone have been used. The most popular biological interposition materials have been skin and fascial arthroplasty with good results reported in 26% to 94% of cases. The technique and early results using cutis have been presented with good early experiences. In the knee, cutis has been shown to undergo metaplasia into a synovial membrane with minimal complications, and some believe that this also takes place in the elbow. The Achilles allograft has been shown to provide adequate bulk and is an attractive option without the concern of harvest sites.
Although the number of reconstruction options available for the arthritic elbow has increased with the progress of metallurgy and implant designs, biological interposition arthroplasty, particularly in the young active patient, continues to be a practical reconstruction option. Functional stability of the elbow is preserved and the likelihood of reankylosis by interposing a biological tissue between the prepared bone ends is reduced. Furthermore, a theoretic advantage of biological interposition is one of preservation of bone stock allowing further arthroplasty reconstruction at a later time and decreasing the possibility of revision surgery noted in younger patients with total elbow arthroplasty. The semi-constrained total elbow arthroplasty can be performed successfully in patients with prior interposition arthroplasty with reliable pain relief and satisfactory results.
INDICATIONS/CONTRAINDICATIONS
Interposition arthroplasty is indicated in the young, working individual with posttraumatic arthritis in whom the demands of the weight restrictions of a total elbow arthroplasty are unacceptable. In this patient population, alternate treatment modalities such as modification of activities, orthotics, and arthroscopic procedures should be thoroughly exhausted. For patients younger than 50 years of age with posttraumatic arthritis of the elbow with good motion but severe pain, this procedure is also recommended ( Table 23-1 ). The younger patient population with inflammatory arthritis, Stage I or II matoid arthritis, where the elbow is stiff or painful but the osseous architecture are maintained, also are well-suited for this procedure. The anatomic requirement is the presence of a wide contour of the distal humerus. Osteosynthesis may be required at the time of the interposition to achieve this requirement, such as cases of distal intercondylar humerus nonunion ( Figs. 23-1 to 23-3 ). The soft tissue envelope around the elbow should be addressed in those cases involving burn patients or severely contracted elbows with hypertrophic scar formation with the assistance of plastic surgery colleagues.
| Patients <50 years old and with: |
|---|
| Posttraumatic degenerative arthritis |
| Primary degenerative arthritis |
| Rheumatoid arthritis (Stage I or Stage II) |
Contraindications for this procedure are those patients with active infection and patients with residual gross instability of the elbow because these cases cannot be adequately stabilized by a biological interposition procedure. Patients with extraarticular ankylosis and paralysis about the elbow that compromises stability are not good candidates. Congenital ankylosis of the elbow has been shown to be deficient in the necessary soft tissue ligamentous and muscular support for biological interposition ( Figs. 23-4 and 23-5 ). Poor soft tissue coverage around the elbow or associated compromised posterior skin also are noted contraindications for this procedure. In addition, for patients with open physis, this procedure is not recommended until bone growth is complete. The patients who use their upper extremities in ambulation or transfer from bed to chair have a relative contraindication because too much loading of the elbow will subvert the joint. We place our patients on a 50-pound lifting restriction. Those patients whose work involves heavy labor and extreme use of force are not ideal candidates for this procedure. These patients may not be good candidates for an arthroplasty of any kind. Patient’s acceptance of precautions and restrictions is of paramount importance for a successful surgical outcome.
SURGICAL TECHNIQUE
The choice of biological material for interposition depends on the surgeon’s preference, availability of biological material, and patient’s choice. We describe our preferred technique, which uses Achilles tendon allograft, as previously described, followed by cutis arthroplasty.
The Achilles tendon allograft provides good bulk, enough material for reconstituting the collateral ligaments when needed and avoiding a donor site ( Fig. 23-6 ). Viral transmission or graft versus host disease are always a concern with allograft material, but to our knowledge no cases of Achilles allograft used in elbow interposition have been reported. The patient should be well informed and actively involved in the decision process and postoperative plan. Ulnar nerve symptoms (via detailed motor and sensory examination) should be noted preoperatively and treated accordingly in surgery with subcutaneous transposition as needed with release of all constricting sites. Radiographic assessment of both the distal humerus and proximal ulna is mandatory. We also recommend evaluation of the wrist and shoulder with radiographic studies obtained as needed directed by the preoperative clinical examination. The clinical examination should document preoperative range of motion and instability of the elbow. Instability is defined as a dislocated or subluxed elbow joint with more than 50% of articular discontinuity. Stability is a major determinant of successful outcome. A computed tomography scan of the elbow can provide improved bone detail when needed as part of a comprehensive preoperative plan.
The patient is prepped and draped in the standard surgical manner. The patient is positioned supine and the affected arm is brought across the chest. We use a standard posterior midline incision. The Bryan/Morrey triceps-sparing posterior approach or the modified posterolateral Kocher approach can be used. The modified posterolateral Kocher approach is described ( Figs. 23-7 and 23-8 ). We develop both medial and lateral fasciocutaneous flaps. The ulnar nerve is identified and mobilized proximally at least 8 cm and distally up to the exit point of the flexor digitorum profundus origin. This is a crucial step because we approach our proximal ulnohumeral and radiocapitellar joint through an extended Kocher approach and a good amount of varus stress is applied to the elbow ( Fig. 23-9 ). Releasing the ulnar nerve will prevent possible iatrogenic compression, which we have seen with this approach when extensive work is done around the elbow. The elbow is then exposed as described by Morrey and colleagues. The extensile Kocher interval is developed distally between the extensor carpi ulnaris and anconeus. The lateral collateral complex is released proximally from the lateral condyle. At this time, varus stress is applied to the elbow once the anterior and posterior capsules have been fully excised. The radial head is preserved because it provides a broad distal half of the articulation, which increases the postoperative stability. The radial head is removed if the arc of motion about the elbow is restricted in pronation and supination. An alternative procedure to facilitate rotation of the forearm is to perform a “radialization” procedure. This is done by removing the ulnar articular margin for the head of the radius. Once the elbow is dislocated, the distal end of the humerus is prepared by removing remaining articular cartilage, ununited bone fragments, osteophytes, heterotopic bone, and fibrous debris as needed. A high-speed burr can also be used to denude and smooth the articular surface, taking care to preserve the subchondral bone. Punctuate bleeding of the subchondral surface is a good indicator of adequate articular cartilage removal. The proximal ulna is contoured by taking care to remove the olecranon incisura to allow a flat articulation on the humerus and concentric fluid joint motion with the newly interposed tissue. Enough bone of the trochlea and capitellum should be removed to accommodate the tendon graft. The distal part of the humerus and olecranon notch must provide ample bone stock to shape the distal end of the humerus into a spacious cancellous bone surface. When possible, a ridge of bone is left medially and laterally on the humerus to stabilize the construct. One should not attempt to reach the subchondral surface of the olecranon because this may predispose the olecranon to fracture when loaded.
