Supracondylar Dome Osteotomy for Cubitus Valgus Deformity Associated with a Lateral Condylar Nonunion in Children

Tien, Yin-Chun MD; Chen, Jian-Chih MD; Fu, Yin-Chih MD; Chih, Tsai-Tung PhD; Hunag, Peng-Ju MD; Wang, Gwo-Jaw MD

Journal of Bone & Joint Surgery - American Volume:
doi: 10.2106/JBJS.C.01545
Scientific Articles
Abstract

Background: Open reduction, autogenous bone-grafting, and internal fixation for the treatment of established nonunion of the lateral condyle associated with a cubitus valgus deformity has a high rate of complications. As a consequence, we developed a new technique that includes in situ compression fixation of the lateral condylar nonunion and a dome-shaped supracondylar osteotomy of the distal aspect of the humerus through a single posterior incision.

Methods: Eight consecutive patients were treated with the new surgical technique between 1994 and 2000. The mean age at the time of surgery was 8.6 years. The mean interval between the lateral condylar fracture and surgery was 4.9 years. The mean preoperative radiographic humerus-ulna angle was 31° of valgus. The postoperative results were classified with a modification of the scoring system described by Dhillon et al., which assesses pain, weakness, range of motion, the humerus-ulna angle, and prominence of the medial epicondyle on a 12-point scale.

Results: All eight lateral condylar nonunions achieved union within three months postoperatively. The mean postoperative humerus-ulna angle was 5.5° of valgus. All of the supracondylar dome osteotomies healed uneventfully, and there was no loss of correction postoperatively. The mean duration of follow-up was 4.5 years. The overall results were excellent in two patients, good in four patients, and fair in two patients.

Conclusions: With better exposure of the lateral condylar nonunion through a posterior approach, we can effectively stabilize the lateral condylar nonunion and avoid postoperative loss of motion and osteonecrosis of the condyle. With a dome-shaped supracondylar osteotomy, we can correct the cubitus valgus deformity and avoid the development of a medial epicondylar prominence. With careful selection of patients, this new technique can be an effective method to treat this clinically challenging problem.

Level of Evidence: Therapeutic Level IV. See Instructions to Authors for a complete description of levels of evidence.

Author Information

1 Department of Orthopaedic Surgery, Kaohsiung Medical College, 100, Shih-Chuan 1st Road, Kaohsiung City 807, Taiwan, Republic of China. E-mail address for G.-J. Wang: gwojaw@cc.kmu.edu.tw

2 Fooyin Institute of Technology, 151 Chinhsueh Road, Ta-Liao Hsiang, Kaohsiung Hsien 831, Taiwan, Republic of China

Article Outline

Open reduction, autogenous bone-grafting, and internal fixation for the treatment of nonunion of a lateral humeral condylar fracture with a cubitus valgus deformity has a high rate of complications1-6. In an effort to achieve reduction of the condyle to its original location, extensive soft-tissue dissection is usually required to adequately mobilize the condyle, which often jeopardizes its vascularity. This can result in osteonecrosis of the lateral condyle1,3,4 and decreased elbow motion2-6. We have developed a new technique that includes the in situ compression fixation of the lateral condylar nonunion and a dome-shaped supracondylar osteotomy of the distal aspect of the humerus to treat the associated cubitus valgus deformity through a single posterior elbow incision. This study analyzes the results of eight consecutive patients treated with this technique to determine the union rate, elbow motion, the ability of the technique to correct the cubitus valgus deformity, and the rate of complications.

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Materials and Methods

Patients were included in this study if they met the following criteria: (1) skeletal immaturity, (2) established lateral condylar nonunion of two years or more, (3) a cubitus valgus deformity of ≥20°, and (4) postoperative follow-up of three years or more. Eight patients who met these criteria were treated with this new technique between 1994 and 2000 (see Appendix). The mean age at the time of the lateral condylar fracture was 3.7 years (range, two to six years). Six children had been treated with immobilization in a cast without closed reduction for three to four weeks. The other two children had been treated by bone setters with only traditional manipulation and local herb paste application. The mean age at the time of our procedure was 8.6 years (range, 4.4 to 12.2 years). The mean interval between the lateral condylar fracture and our definitive procedure was 4.9 years (range, 2.1 to 9.0 years).

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Preoperative Evaluation

The medical records were reviewed with regard to preoperative complaints about cosmetic appearance, pain, joint stability, and ulnar nerve symptoms.

Preoperative physical examination included determination of the range of motion of the elbow, carrying angle, and joint stability and a neurological evaluation. The clinical carrying angle was measured with a goniometer with the elbow in maximum extension and supination.

Preoperative radiographic assessment included anteroposterior and lateral radiographs of both elbows. Only nonrotated or minimally rotated lateral condylar nonunions as demonstrated on radiographs were treated with the new technique. The anteroposterior radiographs were made with the arm in maximum extension and supination. Elbow alignment was assessed by measuring the humerus-ulna angle on the anteroposterior radiographs prior to surgery. Preoperative planning included a tracing of the injured and uninjured elbows on the anteroposterior radiographs. The tracing of the injured side was then reversed and superimposed on the tracing of the normal side to determine the desired corrective angle (α).

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Surgical Technique

The patient was placed in the prone position with the affected extremity resting on an arm support. After inflation of a pneumatic tourniquet, the surgery was performed on the elbow through a midline posterior skin incision extending from 6 cm proximal to 2 cm distal to the olecranon. The lateral border of the triceps muscle was mobilized and retracted medially to expose the lateral condylar nonunion. To avoid postoperative joint adhesions and/or osteonecrosis of the lateral condyle, no attempt was made to mobilize the lateral condyle for the purposes of reduction and only fibrous tissue in the fracture gap was débrided. The lateral condyle was stabilized in situ with two small cancellous compression screws inserted across the lateral condyle into the metaphysis of the distal aspect of the humerus. No bone graft was used in any patient.

The triceps muscle was then split along the midline in order to expose the distal aspect of the humerus for the domeshaped osteotomy (Fig. 1-A). In order to avoid injury to the ulnar nerve, it was routinely identified, released from the cubital tunnel, transposed anteriorly, and protected with a Penrose drain during the procedure. The periosteum was incised longitudinally, and subperiosteal dissection was performed to expose the distal humeral metaphysis. The periosteum of the distal aspect of the humerus is typically very thick and tends to blend rather strongly into the perichondrium. This thick portion needs to be detached by sharp dissection along the junction of the perichondrium. This avoids injury to the physes and articular cartilage. The junction between the periosteum and the perichondrium at the medial border of the distal humeral metaphysis was defined as point A (Fig. 1-B). The intersection of the midline axis and the upper margin of the olecranon fossa (point O) was designated as the center of the dome. With the OA segment as the base, a second line was drawn from point O to form an angle equal to the planned correction angle (α). Furthermore, the intersection of this line and the medial border of the distal aspect of the humerus was designated as point B. The length of segment OB was designated as the radius of the dome. The arc of the dome osteotomy was thus defined by these parameters.

During the osteotomy, two small Chandler retractors were placed alongside the anterior humeral cortex in order to protect the neurovascular structures in the antecubital fossa. Interrupted drill-holes were made along the proposed osteotomy arc with use of a 1.8-mm Kirschner wire. The osteotomy was then completed with a small osteotome. Subsequent to the osteotomy, point B was split into two points, point B' on the proximal fragment and point B” on the distal fragment. Next, the distal fragment of the osteotomized humerus was rotated along the osteotomy arc until point A on the distal fragment met point B' on the proximal fragment. The distal humerus was thus realigned as planned (Figs. 2-A and 2-B).

One medial and one or two lateral crossed percutaneous 1.8-mm Steinmann pins were used to stabilize the osteotomy. During insertion of the pins, the entry and exit points should be directly visualized, thereby minimizing the potential for neurovascular injury and eliminating the need for fluoroscopy. After correction of the cubitus valgus deformity, any initial tension on the ulnar nerve had resolved. The nerve was transposed subcutaneously prior to wound closure. The same surgeon performed all of the procedures in this study.

Postoperatively, the upper extremity was immobilized in a long-arm posterior splint with the elbow in 90° of flexion for three weeks. The affected elbow was then placed in a sling, and the parents were instructed to have the child perform active-assisted extension and flexion exercises for thirty minutes twice a day. However, if the compliance of the patient and family were questionable, immobilization in the splint was continued for another week. The pins were removed at the end of the fourth week in an outpatient clinic.

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Postoperative Evaluation

The operative time, estimated blood loss, neurovascular complications, wound healing, and pin-track condition were recorded.

The clinical carrying angle, range of motion, muscle power, joint stability, and the postoperative scar were assessed by the same examiner at the final follow-up evaluation. To avoid bias, the follow-up examinations were not performed by the operating surgeon. Subjective opinions with regard to the appearance of the elbow and the resultant postoperative scar were recorded. Anteroposterior and lateral radiographs of the elbow were made, and the humerus-ulna angle was measured on the anteroposterior radiograph.

A clinical score was determined for each patient with use of our modification to the scoring system described by Dhillon et al.7 (Table I). This system is based on pain, function, and cosmetic appearance. Function was assessed with use of pain or weakness on activity and the measured range of motion of the elbow. Cosmetic appearance was based on the postoperative humerus-ulna angle. However, the medial shift in the humerus-ulna axis following the osteotomy was added as a fourth parameter to evaluate whether the dome-shaped osteotomy induced a secondary prominence of the medial epicondyle. The medial shift in the humerus-ulna axis was defined as (CD/AB) × 100%, with CD indicating the distance from the olecranon tip to the midline of the humerus and AB indicating the diaphyseal radius at the narrowest portion of the humeral shaft. The medial shift in the humerus-ulna axis was given a score of 3 points when it was ≤100%, 2 points when it was between 101% and 200%, 1 point when it was between 201% and 300%, and 0 points when it was >300% (Table I). The maximum score for this modified Dhillon scoring system was 12 points. A score of 12 points was classified as an excellent result; 10 to 11 points, a good result; 9 points, a fair result; and ≤8 points, a poor result.

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Results

Preoperatively, the cubitus valgus deformity and its progression were the major concerns of all eight patients. However, four patients also had pain in the involved elbow during sports activities. Three children who had elbow pain also complained of a “giving-way” sensation when conducting a pushing-up motion. No patient reported weakness. No muscle weakness in the ulnar nerve distribution was observed on the preoperative physical examination. The preoperative elbow range of motion, compared with that of the contralateral unaffected elbow, was normal in four patients (Cases 1, 5, 6, and 8). Three patients had a flexion contracture that ranged from 10° to 15°, and two patients had lost 10° and 15° of full flexion. The mean preoperative humerus-ulna angle was 31° (range, 24° to 36°). The mean duration of the operation was eighty-one minutes (range, seventy-two to eighty-eight minutes).

No intraoperative complications occurred during any of the procedures. Postoperatively, no patient had a wound or pin-track infection. No percutaneous pins had to be removed prior to the union of the osteotomy. For all eight patients, correction of the deformity was well maintained throughout the immediate postoperative period. No patient had loosening of fixation or loss of correction, and no patient had revision surgery.

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All supracondylar osteotomies of the distal aspect of the humerus healed uneventfully by the end of the fourth week, at which time the percutaneous pins were removed. Postoperative radiographs of the elbow demonstrated that the lateral condylar nonuion united within two months in four patients and within three months in the remaining four patients. Elbow range of motion improved progressively until the sixth month postoperatively and then did not improve further.

The clinical and radiographic postoperative follow-up period was a mean of 4.5 years (range, 3.1 to 7.7 years). At the last follow-up evaluation, the total available arc of elbow motion in the flexion-extension plane improved in three patients (Cases 3, 4, and 7), remained unchanged in four patients (Cases 1, 5, 6, and 8), and decreased in one patient (Case 2). The mean total arc of elbow motion was 131° (range, 120° to 145°) preoperatively and 131° (range, 110° to 145°) postoperatively. No loss of elbow motion resulted from the surgical procedure, except in one boy who lost 10° of motion. Three of the four patients who had preoperative elbow pain had complete relief of pain postoperatively. The remaining patient reported that the preoperative pain had decreased. The three patients who had elbow instability preoperatively had no such symptoms at the time of the latest follow-up.

The mean postoperative humerus-ulna angle at the last follow-up examination measured 5.5° (range, 3° to 9°) of valgus. All patients were satisfied with the overall cosmetic outcome of surgery. Muscle weakness was not reported by any patient or observed in any postoperative assessment. According to our modification of the Dhillon scoring system, the result was rated as excellent for two patients (Fig. 3-A, 3-B, 3-C, 3-D), good for four patients, and fair for two patients. No patient subsequently had a recurrent cubitus valgus deformity or had a medial shift of the humerus-ulna axis.

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Discussion

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Nonunion of a fracture of the lateral condyle can result in a progressive cubitus valgus deformity5,8 and late ulnarnerve neuropathy5,9,10. Currently, there are several treatment options. For ulnar-nerve neuropathy, anterior transposition of the ulnar nerve is a common procedure11,12. Supracondylar osteotomy of the distal aspect of the humerus is also generally believed to be necessary to relieve the tension on the ulnar nerve when the cubitus valgus deformity is ≥20°11,12. However, treatment of the lateral condylar nonunion is controversial because of the reported high rates of complications1-6. Nonetheless, the advantages of treating the nonunion itself that have been reported include improvement in elbow stability11,12, less elbow pain during sports11,12, and the prevention of further progression of the cubitus valgus deformity and possible tardy ulnar palsy12.

In this study, the main indication for treatment was the progression of the cubitus valgus deformity. We used a domeshaped supracondylar osteotomy of the distal aspect of the humerus to correct the deformity. However, we believe that the deformity would have recurred if the nonunion was not repaired because our patients were all skeletally immature. Therefore, the lateral condylar nonunion was stabilized to prevent recurrence of the deformity. The postoperative cubitus valgus deformity was well corrected and was maintained at a mean follow-up interval of 4.5 years. Additionally, the elbow pain that occurred in four patients was relieved in three patients and was decreased in one. The preoperative elbow instability in three patients was also eliminated. However, it should be stressed that only nonunions without substantial rotation should be treated with this new technique.

Attempted anatomical reduction and rigid fixation of the lateral condyle has frequently resulted in complications including loss of motion3-6, osteonecrosis of the fragment1,3,4, and persistent nonunion6,7. It appears that extensive soft-tissue stripping, undertaken while attempting to mobilize and reduce the fracture fragments anatomically, constitutes the main cause of these complications2,11. As a consequence, several authors have recommended in situ arthrodesis, rather than anatomic reduction, of the nonunited lateral condylar fragment2,11,13. To improve the outcome of cubitus valgus secondary to a lateral condylar nonunion, we developed this new technique. In comparing the new method with traditional surgical procedures, three advantages can be readily identified: the need for only a single posterior midline skin incision, a posterior approach to the lateral condylar nonunion, and a dome-shaped supracondylar osteotomy of the distal aspect of the humerus.

The traditional techniques used to treat a lateral condylar nonunion usually require a medial skin incision for anterior transposition of the ulnar nerve and a separate lateral skin incision for bone-grafting and internal fixation of the lateral condyle and a possible concomitant supracondylar corrective osteotomy12. With two scars, the cosmetic appearance can be compromised particularly because the lateral scar crosses the Langer lines in this area and therefore tends to hypertrophy14,15. We have found that the posterior scar is more acceptable cosmetically. Fewer of these scars become hypertrophic, and the posterior location has led to better patient acceptance16.

For nonrotated and minimally rotated lateral condylar nonunions, the fracture can be readily identified on the anteroposterior radiograph. Therefore, the fracture surfaces can be exposed directly through the posterior approach. If no attempt at anatomical reduction of the lateral condylar fragment is made, extensive soft-tissue stripping can be avoided. Under direct vision, the fibrous tissue embedded in the gap between the fracture fragments can be removed with relative ease17. In our experience, only the fracture surfaces over the metaphysis need to be refreshed and the portion in the physis and epiphysis can essentially remain untouched. As part of this technique, the lateral condyle only needs to be fixed in situ by means of two small cancellous compression screws. In this study, all of the nonunions could be easily compressed and no bone graft was necessary. Because the posterior approach allows direct access to the nonunion site and reduces the amount of soft-tissue dissection necessary to achieve compression, the risk of jeopardizing vascularity of the lateral condyle can be avoided. No osteonecrosis of the lateral condyle occurred in this series.

A closing-wedge osteotomy has been used traditionally to correct the cubitus valgus deformity, although there have been a few associated disadvantages4,12. The most frequently reported disadvantage is the loss of correction4. With lateral condylar nonunion, the lateral side of the distal humeral metaphysis usually is somewhat hypoplastic and there may be lateral instability of the elbow12. In order to stabilize the lateral condyle, a layer of heavy fibrous tissue often develops around the nonunion site. In a varus closing-wedge osteotomy, the lateral fibrous tissue is stretched and creates a large valgus moment on the lateral side of the elbow. This valgus moment renders the osteotomy site unstable and makes it difficult to appropriately fix the site to maintain the achieved correction. The second disadvantage to a closing-wedge osteotomy is the resultant decrease in postoperative elbow range of motion12. With a closing-wedge osteotomy, the soft tissues in the lateral aspect of the elbow tend to be overstretched, thus reducing the range of motion of the elbow. Therefore, posterior capsulotomy and partial lateral triceps tenotomy are frequently necessary in order to improve the postoperative range of motion12. The third disadvantage is the possibility of a secondary elbow deformity developing subsequent to surgery. For the closing-wedge osteotomy, a large triangular bone block usually needs to be removed. This typically results in a large difference in surface areas between proximal and distal fragments at the osteotomy site. After positioning the larger distal fragment against the much smaller proximal fragment, a medial epicondylar prominence often results because of a medial translation of the humerus-ulna axis. The cosmetic outcome of the procedure is compromised because of these anatomical changes. When a dome-shaped osteotomy is used, the rotation center of the distal humeral fragment tends to remain at the midline of the humerus, such that only a small rotation arc is necessary to correct the deformity. A much smaller valgus moment is created, and the round distal fragment is well contained within the dome of the proximal fragment. Therefore, with a dome-shaped osteotomy, mechanical stability at the osteotomy site is enhanced and, as evidenced by the results of our study, loss of correction is unlikely to occur. In addition, rotating the distal humeral fragment with its rotation center located at the midline of the humerus decreases the likelihood that it will shift medially to create a medial epicondylar prominence.

We concluded that, with better exposure of the lateral condylar nonunion through a posterior approach, the nonunion can be stabilized effectively and postoperative loss of motion and osteonecrosis of the lateral condyle can be avoided. With a dome-shaped supracondylar osteotomy, we can correct the cubitus valgus deformity and avoid the development of a medial epicondylar prominence. In carefully selected patients, this new technique can be an effective method for the treatment of this clinically challenging problem.

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Appendix

A table presenting clinical and radiographic details on all patients is available with the electronic versions of this article, on our web site at jbjs.org (go to the article citation and click on “Supplementary Material”) and on our quarterly CD-ROM (call our subscription department, at 781-449-9780, to order the CD-ROM).

Investigation performed at the Department of Orthopaedic Surgery, Kaohsiung Medical College, Kaohsiung City, Taiwan, Republic of China

The authors did not receive grants or outside funding in support of their research or preparation of this manuscript. They did not receive payments or other benefits or a commitment or agreement to provide such benefits from a commercial entity. No commercial entity paid or directed, or agreed to pay or direct, any benefits to any research fund, foundation, educational institution, or other charitable or nonprofit organization with which the authors are affiliated or associated.

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