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Advances in the Management of Humeral Nonunion

Pugh, David M. W. MD, FRCSC; McKee, Michael D. MD, FRCSC

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Journal of the American Academy of Orthopaedic Surgeons: January 2003 - Volume 11 - Issue 1 - p 48-59
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Abstract

Approximately 10% of all long-bone fractures occur in the humerus.1 An increasing number of these injuries are insufficiency or fragility fractures secondary to osteoporosis, a result of the rise in age of the general population. Despite advances in the initial management of these fractures, some result in nonunion, requiring further intervention. The factors that contribute to the incidence of nonunion include patient age, mechanism of injury, initial treatment, presence of concomitant injuries, nutritional status, and a history of smoking.1

Because treatment is time consuming and difficult, successful initial fracture management is important. Most humeral shaft fractures can be treated nonsurgically with a high rate of union. Sarmiento et al2 described union rates of 98% for closed and 94% for open fractures of the humeral shaft after functional bracing. Locked humeral nails used for diaphyseal fracture fixation were designed in an attempt to improve union rates for injuries that required surgery. They could potentially minimize morbidity and allow earlier patient mobility compared with open plating techniques. A recent review of complications associated with intramedullary nailing of humeral shaft fractures suggests that the theoretic benefits of locking humeral nails have not been supported by prospective trials.3 Distal humeral fractures routinely require surgical intervention; double-plating these fractures using implants perpendicular to each other has markedly increased the rigidity of the fixation and decreased nonunion rates compared with earlier techniques such as Kirschner wire fixation.4

Humeral nonunions can be grouped by the location of the injury (proximal, shaft, or distal) because each type has characteristics that dictate a specific treatment for a likely successful outcome. Proximal humeral nonunions often are associated with shoulder joint contracture and rotator cuff dysfunction, as well as osteopenia and a tendency for varus deformity. Diaphyseal nonunions that require surgery are often complicated by existing hardware and bone loss.5 Nonunion of the distal humerus is associated with significant elbow joint contracture, synovial pseudarthrosis, poor bone condition, retained hardware, and ulnar neuropathy.6 Each of these complicating factors should be considered during preoperative evaluation and when assessing surgical options.

Proximal Humeral Nonunion

Approximately 40% of all humeral fractures occur in the proximal humerus. They occur most frequently in the elderly (≥65 years) and generally unite within 6 weeks. Malunion is more common than nonunion; the small number of patients whose fractures do not heal are typically symptomatic and have poor shoulder function. The use of hanging casts, skeletal traction, and the occurrence of severely displaced or “four-part” fractures are the most important risk factors for developing nonunion.7-10

Greater Tuberosity

Closed treatment of greater tuberosity fractures may result in posterior and superior migration of the fracture fragment.11 Although displacement of <1 cm is well tolerated, greater displacement may result in subacromial impingement and rotator cuff dysfunction (because of shortening of the musculotendinous units of the rotator cuff) and greater prominence of the tuberosity. Even though malunion is more common than nonunion, surgical reconstruction is indicated in patients presenting with pain or functional limitation attributable to proximal migration of the greater tuberosity fragment. Standard anteroposterior, lateral, and axillary radiographic views of the shoulder usually do not show the bony structure adequately; a computed tomography scan is necessary to determine the exact location of the fragment.

Surgical reconstruction should be done with the patient in a beach chair position using a deltoid-splitting approach to expose the proximal-lateral humerus. Acromioplasty can be performed concurrently if impingement is exacerbating symptoms. Internal rotation of the arm helps to expose the tuberosity; once the fracture fragment is identified, it is important to do an extensive release of the rotator cuff, which will be contracted and shortened because of the malposition of the tuberosity. The defect in the proximal humerus should be débrided and the tuberosity reattached to its native location using cancellous screws with washers. Augmentation of the fixation is often possible using a nonabsorbable suture through the rotator cuff tied as a tension band to the proximal humeral shaft. If the tuberosity is fragmented or is too small to allow fixation, the fragments should be excised and the rotator cuff mobilized and repaired to a bony trough at the articular margin. Rehabilitation is similar to that required for rotator cuff repair.

Neck

Nonunion after surgical neck fractures is more common than previously thought.9 Traction at the fracture site, inadequate immobilization or fixation, and premature motion all contribute to the development of nonunion. The most important determination is whether the humeral head is salvageable (Fig. 1, A). Complicating factors include varus deformity from the unopposed pull of the rotator cuff, severe osteopenia, avascularity of the head or neck fragment, and severe joint stiffness. The joint surface of the humeral head usually is well preserved. In younger (<65 years), active patients, the nonunion should be repaired whenever possible; fixed-angle devices for the proximal humerus have improved the ability to do so. In older patients, hemiarthroplasty is indicated for severe degenerative changes of the articular surface, osteonecrosis of the humeral head, or osteopenia severe enough to jeopardize fixation.10

Figure 1 A,
Figure 1 A,:
Anteroposterior radiograph showing nonunion of the humeral neck in a 48-year-old diabetic woman. The proximal fragment is osteoporotic and tipped into varus; this indicates reasonable vascularity from the attachment of the rotator cuff. B, Postoperative anteroposterior radiograph after correction of the deformity, release of the subacromial adhesion, application of the proximal humeral blade plate, and addition of an iliac crest bone graft. Healing was uneventful.

For primary salvage of a humeral neck nonunion, a blade plate technique can provide optimal stability. It allows sufficient purchase in the humeral head, and the fixed-angle implant minimizes the risk of varus collapse of the proximal humerus that occurs with the use of standard plates, in which the screw-plate angle is not fixed. The patient is placed in a semiseated position with the arm draped free in the surgical field. Through a deltopectoral approach, the nonunion site is identified and débrided. A release is done at the nonunion site to allow proper realignment. The intramedullary canal is recreated, and autogenous bone graft is added. Release of subacromial and periarticular adhesions improves motion and helps decrease stress on the implant. To reduce the risk of impingement from hardware, the insertion site should be just distal to the level of the greater tuberosity. To augment stability of the implant proximally, a screw can be placed into the head fragment adjacent to the blade, creating a triangular construct (Fig. 1, B). If anatomic conditions are favorable, the screw may be inserted in a lag fashion. To neutralize the deforming force of the rotator cuff, a nonabsorbable suture can be placed through it and tied as a tension band around one of the screw heads distal to the nonunion.

Postoperatively, patients should be managed with early pendular and active-assisted exercises, beginning on day 1. A sling may be used for comfort. Full active abduction and flexion should be started at 6 weeks postoperatively, and resistive or strengthening activities initiated with evidence of bony bridging (typically, 8 to 12 weeks). A high rate of union can be achieved when this technique is combined with the liberal use of autogenous bone graft and rotator cuff repair (if necessary). In one series,12 union was achieved in 23 of 25 proximal humeral nonunions, with an accompanying improvement in function. The Disabilities of the Shoulder, Arm and Hand (DASH) score was used to evaluate the patients (0 = normal function, 100 = complete disability). The mean DASH score improved from 77 to 21 points. Patients experienced a notable improvement of pain levels and were able to perform light activities of daily living and personal hygiene at or slightly above the head level.

An alternative method of obtaining fixation in the osteoporotic humeral head is to contour a plate into a blade configuration, using the last hole in the blade portion of the plate to insert a locking screw from the shaft of the plate. This creates a truss construct that is biomechanically superior to a standard plate and helps reduce the toggle of screws.13

For patients not undergoing primary repair, a hemiarthroplasty typically is done with a deltopectoral approach. Any implanted hardware is removed and existing tuberosities are identified. An arthrotomy can be done or, alternatively, the joint entered between the tuberosities if they are malunited or nonunited. The humeral head is then resected, although the distortion of proximal anatomy can make it difficult to use standard cutting jigs. The humeral head osteotomy may need to be done freehand. Reaming the canal and inserting the humeral stem can be difficult if translational malunion has resulted between the shaft and tuberosity, making them noncolinear. Also, the tuberosities may be malunited in a varus fashion, impeding a direct approach down the humeral canal. Preoperative assessment is critical because, rather than undergoing a standard arthrotomy, the tuberosities must be osteotomized so that they may be repositioned. If the humeral stem is to be cemented, care must be taken to avoid leakage through any screw holes from previous fixation in the shaft.

The technical challenges and higher infection rates are two reasons that hemiarthroplasty after failed primary treatment of proximal humeral fractures is a complicated procedure. Hemiarthroplasty routinely yields poor results compared with those of primary arthroplasty done for fracture or arthritis. In a series of 23 patients who underwent arthroplasty for salvage of displaced proximal humeral fractures, Norris et al10 reported pain relief in 95%, but only 53% could perform activities at or above shoulder level. While pain relief is obtainable, restoring motion (especially over the head) is far from assured and depends on the proper positioning of the tuberosities and the integrity of the rotator cuff. Therefore, fixation of the nonunion is the preferred treatment, especially in young patients.

Shaft

Humeral diaphyseal fractures account for approximately 30% of all humeral fractures.1 Nonunion of the humeral shaft occurs in 2% to 10% of nonsurgically treated fractures and in up to 15% of fractures treated by primary open reduction and internal fixation (ORIF).1,2,14,15 Union should occur within 12 to 16 weeks; nonunion is defined as a lack of union within 24 weeks.15 Although troublesome in young patients, humeral shaft nonunion can have a severely deleterious effect on the independence of older patients.

Increased incidence of nonunion is associated with open fractures, high-impact injuries, bone loss or fracture gapping, soft-tissue interposition, unstable fracture patterns, segmental fractures, impaired blood supply, infection, and initial treatment with traction or a hanging cast.1 Preexisting shoulder or elbow stiffness can result in increased motion at the fracture site and thus predispose patients to nonunion. Patient factors such as obesity, osteoporosis, alcoholism, malnutrition, and noncompliance also are influential.1,14,15 Nutritional status and smoking habits should be improved before initiating surgical treatment.

The preoperative assessment should include a complete history, especially evaluating for any symptoms of current or previous infections. A physical examination of the involved limb is required to detect a prior or active draining sinus; unusual erythema or induration of the skin; or tender, swollen axillary lymph nodes. Low-grade infections can be difficult to diagnose from the history and physical examination alone; therefore, laboratory tests should be done preoperatively. Basic blood tests should include a complete blood count, white blood cell (WBC) count, C-reactive protein (CRP) level, and erythrocyte sedimentation rate (ESR). These tests are sensitive, and a normal CRP level and ESR indicate a low likelihood of clinically relevant infection.16 Patients with elevated values should be assessed further with gallium 67 bone scintigraphy and, ideally, an aspirate of the nonunion site for culture.16 A positive culture can help direct antibiotic treatment (both locally and systemically). Unexplained anemia or a cachectic appearance may indicate a nutritional deficiency that should be corrected before surgery. Testing for serum protein or albumin levels also may be indicated in such patients.

In an established humeral shaft nonunion, the salient symptom is functional loss. Although nonunion typically is not as painful as in the lower extremity, the lack of mechanical stability precludes repetitive motion, resistive work, or heavy lifting with the involved upper extremity. In patients with poor intrinsic stability, a flail arm may interfere with personal hygiene, dressing, and simple activities of daily living. In older patients, the functional disability from a humeral nonunion can be severe enough to interfere with living independently.

Nonsurgical treatment of humeral shaft nonunion may be appropriate in certain situations. In older patients, the presence of significant osteoporosis or medical comorbidity can make anesthesia and surgical reconstruction particularly difficult. If only minimal discomfort is present, application of a lightweight orthosis may provide enough stability to achieve an acceptable level of function. In certain settings (eg, no infection, no bone loss), noninvasive treatment, including electrical stimulation, ultrasound, and extracorporeal shock wave therapy, has been used with varying rates of success.17 Given the high success rate of current treatment methods, however, surgery is indicated for most patients.

The goal of surgery is to achieve stable internal fixation and institute early motion. Although a variety of techniques has been described, including locking intramedullary nails, unilateral external fixators, and circular external fixation, the preferred treatment is compression plating with the addition of autogenous iliac crest bone graft, as the success rate has been high.5 The mechanical and biologic features of the nonunion have a direct bearing on the optimal surgical treatment. For hypertrophic nonunions, establishing mechanical stability alone is usually sufficient to allow healing without the need for additional bone grafting. Atrophic nonunion, on the other hand, indicates a suboptimal healing response that requires the addition of a biologic stimulus, such as an autogenous bone graft, and stable internal fixation. The presence of infection or marked bone loss (>4 cm) indicates a need for change in the reconstructive technique.

Surgical Technique

An anterolateral approach that allows extension both proximally and distally usually can be used. A posterior approach is reserved for nonunion of the distal humerus in which insufficient length is available for three or four screws distally above the olecranon fossa. In such cases, a posterior approach is preferred in order to apply two (small fragment) plates distally along the medial and lateral columns to enhance fixation.

With an anterolateral approach for a nonunion in the proximal shaft, the deltoid insertion can be protected by twisting the plate so that distally it lies anterior to the deltoid insertion and proximally lies lateral to the biceps tendon. This may be preferable when preservation of deltoid strength and function is critical, such as when there is concomitant inferior pseudosubluxation of the humeral head (which is exacerbated by deltoid dysfunction).18 In general, the anterior portion of the deltoid insertion can be reflected, if necessary, with minimal functional consequence. For midshaft or distal shaft nonunions, the radial nerve is identified between the brachialis and brachioradialis muscles, and an external neurolysis is done to isolate and protect the nerve throughout. In atrophic nonunions or those with an established synovial pseudarthrosis, the nonunion site is exposed and débrided to healthy, bleeding, viable bone. Any synovial tissue at the nonunion site must be resected. The intramedullary canal also should be reestablished because it is an excellent source of osteoprogenitor cells. Sufficient dissection and release is done to allow correction of any deformity and to obtain apposition of the bone ends. It may be necessary to shorten the humerus to provide end-to-end bony contact; loss of up to 3 or 4 cm in length does not appear to have any notable detrimental functional effects. Shortening >4 cm is not desirable from either a functional or cosmetic standpoint; other methods to treat the defect are necessary.

The pathologic features of the nonunion fracture fragments can be used in the surgical technique. If possible, two oblique surfaces can be fashioned and a lag screw placed across the nonunion to facilitate compression. Otherwise, compression is achieved by inserting the plate in compression mode. A 4.5-mm compression plate placed laterally or anterolaterally with staggered holes allows the surgeon to avoid inserting screws in a single longitudinal plane, which can lead to fissuring or splitting of the bone. At least four screws (eight cortices) should be used above and below the nonunion, or three screws (six cortices) if a solid lag screw has been applied. When bony débridement has been extensive and the defect at the nonunion site is greater than that which can be accommodated by compression with the plate, the external device can be used to close the gap and apply compression. Liberal use of autogenous bone graft or another osteoinductive agent is imperative in atrophic, biologically inactive situations.

Hypertrophic Nonunion

Hypertrophic nonunion usually occurs when nonsurgical care fails in the setting of a vigorous healing response and poor mechanical environment, or after surgery with inadequate fixation. Generally, this type of nonunion requires mechanical stability and compression to obtain union. It does not need to be débrided but instead should be treated with a broad 4.5-mm plate on the convex side of the bone (typically anterolaterally, as in a humerus with varus deformity). Compression is achieved by sequential insertion of the screws proximally to distally relative to the nonunion site; pulling the shaft up to the straight, uncontoured plate; and correcting the deformity. The broad surfaces of the nonunion usually allow placement of lag screws for additional compression and stability. Newer plate designs that have undercut holes allow insertion of screws at steeper angles, which facilitates lag screw insertion through the plate. Bone graft in this situation is not necessarily required (Fig. 2).

Figure 2 A,
Figure 2 A,:
Anteroposterior radiograph of humeral shaft nonunion in a 37-year-old woman 14 months after treatment with bracing. Anteroposterior (B) and lateral (C) radiographs 4 months after ORIF with a broad 4.5-mm compression plate and a lag screw (through the plate), showing solid union. The nonunion was not “taken down” or bone grafted. Given the biologic response and callus at the fracture site, it was anticipated that stable fixation and compression would be adequate to achieve union.

Infection

Infected nonunion of the humerus is a difficult challenge. The nature of the surgical intervention depends on the condition of the patient, the infecting organism or organisms, and local conditions at the nonunion site. Initial studies should include a history, physical examination, and basic blood tests, including WBC, CRP level, and ESR. If the diagnosis is not established, a gallium 67 bone scan can confirm the presence of infection.16 Previous cultures or an aspirate can identify the infecting organism or organisms and direct treatment. Antibiotics are withheld preoperatively to avoid compromising definitive deep intraoperative cultures. This is followed by a thorough débridement and irrigation. Immediate fixation can be done in a healthy patient (eg, with no cancer or immunodeficiency, nondiabetic, nonsmoking) with a single, nonvirulent organism (eg, Staphylococcus epidermidis) and good soft-tissue coverage. Fixation can be optimized at the nonunion site with antibiotic-impregnated calcium sulfate, which elutes a tremendously high local concentration of antibiotics and is osteoconductive, or with antibiotic-impregnated methylmethacrylate cement beads.16

In the absence of these conditions, the nonunion should be stabilized with an external fixator followed by serial débridements, during which repeat cultures should be taken. To assist in creating an optimal environment for infection control, placement of an antibiotic bead pouch with antibiotic-impregnated bone substitute or bone cement is beneficial.16 When the wound is clean and dry and laboratory test (ESR and the CRP level) results have returned to normal (typically between 6 and 12 weeks postoperatively), definitive fixation with compression plating and bone grafting can be done. If a bony defect is present, any grafting procedure should be delayed until the infection is eradicated. Ambiguous cases are evaluated with repeat aspiration of the nonunion site for culture.

Another treatment option for infected nonunion of the humeral shaft is the application of a circular fixator. Indications include osteopenic bone, failed conventional surgery, and anticipated difficulty in eradicating infection (ie, a compromised patient, presence of a virulent organism, or both). This technique can provide stable fixation even in the presence of osteopenia or bony defects, and it has the advantage of not requiring any implanted metallic devices at the nonunion site. Compression is applied through the frame, and bone grafting usually is not necessary, although some shortening may occur at the nonunion site. Patel et al19 reported healing in 15 of 16 patients treated in this manner (all had failed previous surgery). Lammens et al20 reported success in 28 of 30 patients. Disadvantages include the length of time in the frame (a mean of 6 to 8 months), the potential for neurovascular injury, even in experienced hands (5% to 19%), and refracture after frame removal (13%).20

Bone Loss

When extensive segmental bone loss has occurred, either as a result of the initial injury or because of extensive débridement, advanced treatment techniques are needed. A defect of 3 to 4 cm can undergo acute shortening and plate fixation. For greater bone loss, other reconstructive options should be considered. These include vascularized fibular transfer (Fig. 3), corticocancellous autografts, humeral allografts, or bone transport using a circular fixator.19-23 Each method requires débridement of all nonviable tissue, reestablishment of the intramedullary canal, graft interposition with stable fixation, and cancellous autografting at both ends of the interpositional graft.

Figure 3 A,
Figure 3 A,:
Anteroposterior radiograph of a humeral shaft nonunion with extensive diaphyseal bone loss after a high-velocity gunshot wound complicated by infection in a 53-year-old woman. The size of the defect is too great for shortening or nonstructural bone graft. B, Postoperative anteroposterior radiograph showing reconstruction with vascularized fibular graft, autogenous iliac crest bone grafting of the junction sites, and plate fixation. After 6 months of healing, arm function improved dramatically. This specialized technique is appropriate for patients with defects ≥5 cm.

Another method that can be used to treat atrophic nonunions with bone loss is the waveplate technique recently described by Ring et al.24 The plate is an integral part of a technique designed to limit dissection, preserve local blood supply, bridge the nonunion gap, and provide abundant local cancellous bone graft to stimulate healing. The wave in the plate at the level of the nonunion may provide some mechanical advantage to the nonunion, although results are inconclusive. Ring et al24 reported healing in 14 of 15 patients (mean preoperative bony defect, 3 cm).

Nonunion After Locked Humeral Nailing

The first generation of intramedullary devices for fixation of humeral fractures involved considerable problems with rotational and axial instability, nail migration, and insertion site discomfort. Locked nails were designed to ameliorate some of these problems but, unfortunately, nonunions still occur despite these implants. Surgeons often are faced with a considerable reconstructive dilemma when nonunion is associated with a failed locked humeral nail (broken nails or screws). Nail removal through the rotator cuff can compromise postoperative function. Bone loss, often sufficient to compromise cortical integrity, commonly occurs at the nonunion site and in the distal humerus around a loose nail. Exchange nailing of these injuries generally does not provide a reliable means of obtaining union. In a retrospective multicenter review,25 only 4 of 10 patients achieved union with exchange nailings, whereas 9 of 9 did so with conversion to plate fixation with autogenous bone grafting (Fig. 4). Robinson et al26 reported success in only two of five cases of exchange nailing after unsuccessful Seidel nailing.

Figure 4 A,
Figure 4 A,:
Anteroposterior radiograph showing diaphyseal nonunion after failure of a Seidel nail. Note the bone loss around the distal end of the nail (arrow). With a loose nail, this can be severe enough to jeopardize cortical continuity and screw purchase. B, Reconstruction consisted of removing the nail and locking screw, performing blade plate fixation, and applying autogenous iliac crest bone graft. A blade plate was used because of the poor proximal bone quality after nail removal. (Reprinted with permission from McKee MD, Miranda MA, Riemer BL, et al: Management of humeral nonunion after the failure of locking intramedullary nails. J Orthop Trauma 1996;10:492-499.)

Patel et al19 recently described the use of the Ilizarov technique to treat humeral shaft nonunion. In 10 patients with nonunion after insertion of large-diameter humeral nails, the authors left the nail in situ, removed locking screws (if present), applied a circular fixator, and compressed the nonunion site with the frame. They reported healing in all 10 patients (mean time to union, 4 months), but the complication rate was high. There were three patients with temporary nerve palsies; three cases of excessive shortening (4 cm, 7 cm, and 8 cm); nail protrusion requiring removal; and numerous pin tract infections. Although this method seems to be an attractive option, the specialized technique and high complication rate may limit its general use.

Results

Union rates of 0% to 60% have been reported with noninvasive methods such as ultrasound or electrical stimulation.15,17 The ideal patient for these therapies has a stable, straight, noninfected delayed union or nonunion, with no bone loss, that requires biologic intervention to heal.15,17 Such patients are rare.

Union rates after surgical repair using compression plating and bone grafting are excellent, ranging from 83% to 100%, with a high rate of patient satisfaction.5,13,15,24,25 Otsuka et al5 reported success in 25 of 25 humeral shaft nonunions treated with compression plating. They also noted that the prognosis after surgical repair of a humeral shaft nonunion depends on a number of factors, some of which are beyond the control of the surgeon. Otsuka et al5 suggested that the presence of comorbid factors (ie, medical, medicolegal) had a notably negative effect on scores on the Medical Outcomes Study 36-Item Short Form, which measures general health status, but had no effect on the joint-specific Constant (shoulder)27 or Mayo (elbow)28 scores. Although patients typically improve with successful surgery, it may be impossible to provide a “normal” state if significant comorbidity is present. Otsuka et al5 also showed that the duration of the nonunion has no effect on ultimate functional or joint-specific scores after successful treatment.

It is difficult to accurately determine the prognosis for humeral nonunion complicated by infection, segmental bone loss, or poor patient nutrition. Information must be determined from larger studies of general humeral nonunion. Excellent union rates (88% to 95%) can be anticipated when principles of infection eradication are followed or when specialized techniques such as fibular grafting or circular fixation are used.19,20,22 Inappropriate application of hardware or bone graft, or both, to an infected nonunion site should be avoided. In most studies, patients who abuse alcohol are overrepresented in the group of patients with complications because of factors common in this population. These include prevalence of falls, postoperative withdrawal symptoms with delirium or seizures, severe osteopenia, malnutrition, and heavy cigarette smoking.15,22

Distal Humeral Nonunion

Only 20% to 30% of humeral fractures involve the distal aspect of the bone.21 During the past two decades, advances in implants and surgical techniques, and recognition of the importance of early motion postoperatively, have resulted in immediate ORIF being the standard of care for displaced fractures. Nevertheless, the incidence of nonunion is still as high as 10% after ORIF, most commonly because of inadequate fixation.4,29 Other factors that predispose to nonunion include open fractures, fracture comminution, high-energy injuries, and infection. The incidence of nonunion appears to be higher in elderly women.21,30 In fractures treated nonsurgically, premature motion also is responsible for nonunion.

Distal humeral nonunion is very disabling. In addition to symptoms of pain, decreased range of motion, and poor function, patients often have associated ulnar neuropathy.31 Instability and weakness also are common.32 In planning surgical treatment, patient factors such as age, medical status, previous surgery and associated scars, adequacy of the soft-tissue envelope, and the presence of other upper limb disabilities should be considered.

Quality of bone stock, presence of articular disease, degree of joint contracture, and severity of deformity are important limb factors to consider. A successful outcome from osteosynthesis requires adequate bone stock and minimal articular degeneration; in addition, joint contracture (which is almost always present) must be correctable. Arthroplasty should be considered for poor bone stock, severe deformity, or irreversible joint disease. Arthrodesis is appropriate for patients with nonreconstructable joints who are not eligible for arthroplasty because of infection or concerns about compliance. Arthrodesis also is a reasonable option in young, active patients whose nonunion is complicated by irreversible joint damage, bone loss, or infection. However, elbow arthrodesis is extremely limiting functionally and should be considered a salvage procedure with the limited goals of stability and pain relief.

Careful evaluation of the soft-tissue envelope is necessary before surgery. It is quite common for a patient to have undergone numerous surgeries of the elbow, often through a number of incisions. In rare cases, tissue expansion can be done as a staged procedure to allow for appropriate coverage; or local rotational flaps or even free flaps may be required, which influences the choice of planned bony reconstruction. The neurologic status of the limb must be evaluated carefully; preoperative electromyographic studies can help determine if local nerve compression should be treated surgically. Ulnar nerve palsy resulting from scarring and fibrosis after failed primary fracture care is common; it is important to determine whether ulnar nerve transposition has been done. Ulnar nerve recovery is advisable after adequate release and neurolysis in these patients, although it may take up to 2 years for intrinsic muscle strength and bulk to return.33

Surgical Technique

The patient is positioned in the lateral decubitus position with the affected arm placed over a bolster. A sterile tourniquet is useful to allow more proximal exposure, if necessary. A long (15 to 25 cm), midline posterior incision is made, with previous incision lines incorporated, if possible. The ulnar nerve is identified proximally, and an external neurolysis is done to mobilize the nerve. The nonunion usually is between the capitellum and trochlea, or between the metaphyseal and diaphyseal fragments, and can be approached by splitting the triceps longitudinally. Alternatively, the olecranon can be osteotomized and the triceps reflected proximally. The nonunion is identified and the bone ends débrided. Injuries of the distal humerus commonly are associated with significant joint contracture with arthrofibrosis. An extensive joint release should be done, clearing the olecranon fossa and removing any osteophytes. The anterior capsule can be approached through the nonunion site or by dissecting around the lateral side and entering through a separate anterolateral arthrotomy site.

Provisional fixation of the nonunion is obtained with Kirschner wires. Definitive fixation consists of two plates oriented at 90° angles to each other. The preference is to use a 3.5-mm reconstruction plate posteromedially and a precontoured J plate directly laterally.4 As much distal fixation as possible is obtained. For very distal nonunions,33 it is sometimes necessary to use a third plate posterolaterally. Autogenous bone graft from the iliac crest is used liberally. The olecranon osteotomy is fixed using a predrilled 6.5-mm cancellous screw with a tension band, and an anterior subcutaneous transposition of the ulnar nerve is done (Fig. 5). Articulated hinge fixators generally are not necessary because both the medial and lateral collateral ligaments (with their origins on the distal fragment) are intact. Joint stability is maintained if appropriate care is taken during the procedure.

Figure 5
Figure 5:
Anteroposterior (A) and lateral (B) radiographs of a distal humeral nonunion in a 68-year-old man after nonsurgical treatment of a transcondylar fracture. There is minimal deformity, reasonable distal bone stock, and no degenerative change, which made the nonunion appropriate for reconstruction. Anteroposterior (C) and lateral (D) radiographs after reconstruction using stable fixation with contoured plates on the medial and lateral columns, autogenous bone grafting, and joint contracture release through a posterior approach. At 1 year postoperatively, elbow motion measured 25° to 13°, and the nonunion was united.

Early motion is instituted on the first postoperative day. Unless the olecranon or triceps needs to be protected, full active motion is initiated under the supervision of a physiotherapist. Extension splinting is often beneficial to decrease the risk of flexion contracture. Continuous passive motion, especially in association with axillary block analgesia, is used for severe or recurrent contracture. Because anti-inflammatory medications such as indomethacin may be detrimental to fracture healing, they should not be used routinely for prophylaxis against the development of heterotopic bone.34

Open Reduction and Internal Fixation

Osteosynthesis remains the treatment of choice in young patients with good bone stock. In 1982, Mitsunaga et al30 reported their 10-year experience with 25 patients, who achieved an 88% union rate (average time to healing, 7.7 months). Twenty-four percent of the patients needed additional surgery to achieve union. Complications of nerve palsy or infection were noted in four patients. Although the authors showed that union could be obtained, the average increase in range of motion was only 9°. The authors correctly concluded that the goals of union and motion are often in conflict and that stable fixation allows shorter periods of immobility and may lead to better motion.30

In another series of 20 patients with distal humeral nonunion, 17 were treated surgically, with 15 undergoing ORIF and autogenous bone grafting.21 Union was achieved in 94%, with an average elbow flexion-extension arc of 74°. Complications were limited to one radial nerve palsy that spontaneously recovered within 2 months and an infected distal humeral allograft that required débridement and reimplantation of a second allograft. Overall function was rated excellent in one patient, good in six, fair in seven, and poor in six. The authors recognized the importance of rigid internal fixation with the addition of autogenous bone graft as an adjunct to obtain bony union. They also concluded that the presence of intraarticular nonunion or associated severe soft-tissue trauma was a poor prognostic factor.21

In 1994, McKee et al6 reported on a series of 13 patients with distal humeral nonunion or malunion. Surgery in all cases involved an extensile exposure, mobilization, and transposition of the ulnar nerve; external neurolysis, when necessary; anterior and posterior capsulectomy; articular defect reconstruction; rigid fixation with plates; iliac crest bone grafting; and a postoperative protocol that stressed early motion. Union was achieved in all patients, with a mean increase in motion arc from 45° preoperatively to 97° postoperatively (mean follow-up, 25 months). No notable complications occurred. The improved results can be attributed to the application of rigid fixation and bone grafting, complete capsular release, ulnar neurolysis or transposition, and initiation of early motion.

Total Elbow Arthroplasty

Treating distal humeral nonunion with total elbow arthroplasty has been described by many authors.28,35,36 The surgical indications are a nonreconstructable distal fragment and the presence of posttraumatic arthrosis. Generally, this technique should be reserved for elderly or less active patients28 (Fig 6).

Figure 6
Figure 6:
Anteroposterior (A) and lateral (B) radiographs of a distal humeral nonunion in a 72-year-old woman. Her deformities included varus and severe malrotation (panel B), poor distal bone stock, and severe joint contracture—poor prognostic indicators for nonunion repair. Postoperative anteroposterior (C) and lateral (D) radiographs of semiconstrained total elbow arthroplasty used for reconstruction. The condyles and distal fragment are simply resected, creating a working space distally that facilitates elbow release and component insertion without violating the triceps insertion. Rehabilitation was rapid, and the patient had a pain-free, stable, 120° arc of flexion-extension 6 months postoperatively.

The early reports have not been encouraging. Seven patients with distal humeral nonunion30 were treated with semiconstrained total elbow arthroplasty; two required revision of loose humeral components within 32 months of the initial surgery. Another patient sustained a radial nerve injury from extruded cement and required tendon transfers. Improvements in pain and motion (average arc, 103°) in all patients were reported at final followup.30 In 1989, Figgie et al36 reported on 14 patients treated with semiconstrained total elbow arthroplasty for established distal humeral nonunion. Seven postoperative complications occurred in five patients; three had surgical revision. Three patients had wound-healing problems and one had nerve palsy requiring revision surgery. Despite these complications, subjective improvement in both pain and function was noted at a mean follow-up of 5 years. A 100° arc of motion was described for the elbows that did not require revision surgery. The authors emphasized the need to maintain the epicondyles with their associated muscle attachments to improve the stability of the elbow.

In 1995, Morrey and Adams28 described their 8-year experience using the Coonrad-Morrey semiconstrained elbow replacement for treatment of distal humeral nonunion. They reported results in 36 surviving patients (mean follow-up, 50.4 months). Good or excellent results were noted in 86% of patients, with an average arc of motion of 111°. Seven patients suffered serious complications (requiring revision surgery in five). There were two deep infections, two cases of particulate synovitis, one case of worn bushings, and two partial ulnar nerve palsies. The authors recommended arthroplasty as a treatment option in elderly patients or those with nonreconstructable distal fragments. They also recommended maintaining the triceps insertion on the olecranon and working through the space created by excision of the distal humeral fragments. This allowed for easier, quicker rehabilitation without risk of detaching the extensor mechanism.

For total elbow replacement, the patient is placed in a lateral decubitus position, with bolsters or a bean bag and an axillary roll under the dependent arm. After inflation of an upper arm tourniquet, a direct posterior skin incision is made. Skin flaps are elevated to expose the medial and lateral extent of the triceps. The ulnar nerve is initially identified, freed from scar tissue, and protected (it is transposed anteriorly at the conclusion of the procedure). The triceps is elevated off the distal humerus, but its insertion in the olecranon is maintained. Any retained hardware is removed. The common flexor and extensor origins are released from the epicondyles, along with the collateral ligaments. These tissues are reattached to the fascia after component insertion. The distal humeral fragments are removed. The anterior capsule can be elevated off the anterior humerus to allow increased extension range. By externally rotating the ulna, the intramedullary canals of the humerus or ulna can be accessed in preparation for prosthesis implantation. After a trial reduction, the semiconstrained humeral and ulnar implants are cemented into position and linked with a coupling bolt. If hardware has been removed, it is important to ensure that no methylmethacrylate extrudes through the screw holes in the humerus or ulna during implantation. After secure wound closure, the patient is placed in a padded Jones dressing in extension. On postoperative day 1, a light dressing is placed on the arm and early motion is begun. Night-time extension splinting is used to reduce the risk of developing a flexion contracture.

Summary

Successful treatment of humeral nonunion can be achieved by applying strict principles of stable internal fixation with the liberal use of autogenous bone graft. Fixed-angle devices improve fixation and maintain correction of deformity in difficult proximal nonunions. Open reduction and plating is more reliable than nailing for all diaphyseal nonunions, including nonunion after intramedullary nailing. In distal humeral nonunion, careful attention to the release of joint contractures, combined with nerve releases (when appropriate) and stable internal fixation with dual or triple plating, provides good functional results in most cases. After surgical treatment, surgeon-based, joint-specific outcome measures improve markedly, although the patient's general health status may depend more on comorbidity or compensation status. Arthroplasty of the shoulder (for proximal nonunion) or elbow (for distal nonunion) are reasonable options in older, lowdemand patients if bony reconstruction is not feasible.

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