Nonunion of the Radial Neck Following Operative Treatment
for Displaced Radial Head and Neck Fractures

Ho-Jung Kang*, Sang-Jin Shin** ,Sung Shik Kang**

Address for Correspondence

Sang-Jin Shin MD ADDRESS: Department of Orthopedic Surgery,
Ewha Womans University School of Medicine
911-1, Mok-Dong, Yangcheon-Ku, 158-710, Seoul, Korea
TEL: 822-2650-5010
FAX: 822-2642-0349
E-Mail: sjshin622@ewha.ac.kr

Abstract:

Introduction: Nonunion of the radial neck is uncommon after the operative treatment of displaced radial head and neck fractures. Treatment of nonunion of the radial neck remains the subject of debate and various treatment options have been introduced. This study presents six patients with nonunion of the radial neck following operative treatment for displaced radial head and neck fractures and the long-term clinical outcomes of conservative treatment for nonunion of the radial neck.
Material and methods: Three hundred and twenty-six patients underwent operative treatment for displaced fractures of the radial head and neck from 1996 to 2008 and six of these patients (1.8%) were diagnosed as nonunion of the radial neck. No additional surgical treatment was undertaken after nonunion was confirmed. Times from primary operation to diagnosis of nonunion, clinical presentations, radial head-shaft angle, ranges of motion and residual angulations on plain radiographs were documented. Functional outcomes were evaluated using the Mayo elbow performance index (MEPI) at final follow-up visit
Results: Average time from primary operation to diagnosis of nonunion was 10.2 months. Five patients demonstrated neither functional deficits nor clinical discomforts when nonunions were confirmed. Another patient complained of mild elbow discomfort only when lifting heavy weights. But, all patients achieved satisfactory clinical outcomes after an average follow-up of 7.6 years.
Conclusion: When there were no clinical symptoms of radial neck nonunion regardless of radiological findings, no further surgical treatments were recommended.

Keywords:

radial neck fracture; surgical treatment; complications;nonunion.

J.Orthopaedics 2011;8(1)e10

Introduction:

The fractures of the radial head and neck account for 1.5-4% of all fractures and 25-33% of elbow fractures.1,2 Minimally displaced radial head and neck fractures have been consistently achieved satisfactory clinical outcomes, regardless of treatment methods.1 However, the are prone to displacement and comminution when associated with other injuries, such as, elbow dislocation, collateral ligament disruption and fracture of the coronoid process.3 Operative treatment is required to treat a mechanical block of elbow motion due to the fracture fragments and unstable fractures combined with dislocations. The optimal operative method for displaced radial head and neck fractures is controversial, with conflicting evidence supporting open reduction and internal fixation, radial head excision and radial head replacement.3,4 Furthermore, the traditional concept of “resect the radial head if in doubt” has been set aside in favor of “preserve the radial head if possible”.3 Despite good functional outcomes after operative treatment, fixation failures, malunion, nonunion and avascular necrosis have been reported as complications.5 Among them, nonunion of the radial neck following an operative treatment is known to be an uncommon complication.6,7,8 Accordingly, the treatment of nonunion of the radial neck remains the subject of debate and various treatment options have been introduced.5-7 In this study, the authors present six patients with nonunion of the radial neck following operative treatment for displaced radial head and neck fractures and the long-term clinical outcomes of conservative treatment for nonunion of the radial neck.

Materials and methods:

Three hundred and twenty-six patients underwent operative treatment for displaced fractures of the radial head and neck from 1996 to 2008 and six of these patients (1.8%) were diagnosed as nonunion of the radial neck. There were three men and three women of average age 30.7 years (range, 14-48 years) at the time of injury. The dominant extremity was involved in two of the six patients. Three patients had fractures resulting from a fall onto an outstretched hand, two patients were involved in a motor vehicle accident and another patient was injured during a bicycle accident. Fractures in four patients were classified as type III and in two as type II, according to the Mason classification (Table 1). Three patients had combined injuries, such as, an Essex-Lopresti fracture or a Monteggia fracture (Fig. 1). There were no associated neurovascular injuries. Preoperative radial head-shaft angles were measured by plain radiography in anteroposterior view. Radial head-shaft angle was defined as the angle between a line perpendicular to the articular surface of radial head and the line drawn down the center of the radial shaft.
All patients underwent operative treatment within an average of 3.8 days after injury. Three patients were treated by open reduction and internal fixation with plate and screws. One patient underwent open reduction and internal fixation with a Herbert screw and K-wires. Another patient was managed by open reduction and pinning, and the sixth was treated with a long arm cast after open reduction without any fixation. A long arm splint was applied with the elbow in 90° of flexion after surgery and three days after surgery, splints were changed into a hinged brace to allow elbow range of motion exercise, excepting the patient with cast immobilization. Nonunion of the radial neck was diagnosed by plain radiography and CT (computerized tomography) when diagnosis was equivocal by plain radiography. Times from primary operation to diagnosis of nonunion, clinical presentations, elbow ranges of motion and residual angulations of the radial head and shaft on plain radiographs were evaluated. After confirming nonunion, no additional surgical treatment was administered to any of the six patients. Functional outcomes were assessed using the Mayo elbow performance index (MEPI) at final follow-up visit, which were conducted at an average of 7.6 years (range, 2-14 years) after diagnosis of nonunion.

Table 1. Patient demography

* Fracture type was classified according to the Mason classification,  MVA : Motor vehicle accident

Figure

Fig. 1. Radial neck nonunion was found in 29 year old patient after operative treatment for combined radial neck fracture with Monteggia fracture.

Results:

The average time from primary operation to diagnosis of nonunion was 10.2 months (range, 6-15 months). Five patients demonstrated neither functional deficits nor clinical discomforts when nonunions were confirmed (Fig. 2). Another patient complained of mild elbow discomfort only when lifting heavy weights. Four were diagnosed as nonunion by plain radiography during follow-up and another patient suspected of having nonunion by plain radiography was confirmed by CT (Fig. 3). Of the three patients who underwent concomitant operations due to associated injuries, two requested to remove hardware of radial head as well as forearm and wrist simultaneously despite no functional deficits. One of these two patients was diagnosed as nonunion of radial neck at the time of hardware removal (Fig. 4). During the operation, fibrous tissues were found between the radial head and neck without any evidence of bony union. However, the distance between the radial head and capitellum was not changed and no instability of the radial head was observed. After hardware removal without any additional treatment, the patient demonstrated no functional deficit during daily activities. No subsequent complications, such as, heterotopic ossification, early fixation failure and infection were demonstrated by any of the six patients.
The average preoperative radial head-shaft angle was 29.7° (range, 3°-60°) and anatomical reduction was achieved in all six patients after primary operation. However, average radial head-shaft angle at the time of diagnosis of nonunion was 18° (range, 9°-30°). Residual radial head-shaft angle further changed from the time of diagnosis of nonunion by an average of 10° in two patients at final follow-up (Fig. 5). At physical examinations conducted at final follow-up, both showed cubitus valgus deformities. Nevertheless, the functional outcomes of these two patients were good; no functional deficit or weakness was apparent and the patients were satisfied with their outcomes (Fig. 6). At final follow-up visits, all patients demonstrated a satisfactory functional range of elbow motion: average supination was 77° (range, 65°-80°);  pronation 75° (range, 60°-80°); flexion 128.3° (range, 120°-140°); and extension 7.5° (range, 0°-10°). Average Mayo elbow performance index at final follow-up was 96.7 (range, 85-100) (Table 2).

Table 2. Clinical outcomes of radial neck nonunion at an average 7.6 years follow-up

Radial H-S angle: Radial head-shaft angle, MEPI : Mayo elbow performance index

Fig. 2. 47 year old patient demonstrated neither functional deficits nor clinical discomfort when nonunions were confirmed.

Fig. 3. A patient suspected of having nonunion by plain radiography was confirmed by  

Fig. 4. (A) Plain radiographs at 1 year after open reduction and plate fixation for displaced radial head and neck fracture. Nonunion of radial neck is suspicious but not definitely shown. (B) Nonunion of radial neck was confirmed at the time of hardware removal.

Fig. 5. Residual radial head-shaft angle further changed from the time of diagnosis of nonunion by 10° at final follow-up.

Fig. 6. 14 year old patient developed cubitus valgus deformity after radial neck nonunion.

Discussion:
The authors reported six patients with nonunion of the radial neck following operative treatment for radial head and neck fractures that obtained satisfactory functional results after conservative treatment at an average follow-up of 7.6 years.
Nonunion of a radial head and neck fracture is known to be caused by many factors.5,6,9 Disruption of the vasculature to the radial head and neck at the time of injury is likely to be an important contributory factor. And an improper surgical technique causing devascularization or interfragmentary defect due to comminution may also lead to iatrogenic soft tissue and vascular damage. Early loss of fixation after inadequate internal fixation and early rehabilitation despite unstable fixation might also contribute. In this study, all fractures resulted from high energy injuries and the patients all underwent surgical treatment utilizing various fixation methods which might have compromised the vasculature to the radial head and neck.
Theoretically, the incidence of nonunion of the radial head and neck after a fracture involving the radial neck would seem to be high due to unique anatomical structures of the radial neck. The radial epiphysis is contained within the elbow joint capsule and the radial head has a tenuous blood supply with limited soft tissue attachments.10 Thus, high energy injury can disrupt the vascular structure or surgical manipulation further increase the damage to soft tissue and blood supply. However, contrary to our expectations, nonunion of the radial neck has been reported to be uncommon, although it should be added that no report has determined the accurate incidence of radial neck nonunion as a postoperative complication.6-8  In the present study, we found the incidence of nonunion of the radial neck following operative treatment was 1.8 %. Nonunion of the radial head and neck might be underestimated because radiographs are not taken until symptoms are aggravated. Furthermore, often it is difficult to diagnose nonunion on plain radiographs because of small fragments of the radial head and coverage by hardware. Vague symptoms derived from radial neck nonunion are one of contributing factors for delayed diagnosis. More careful evaluations would have shown higher incidence of nonunion.

Various treatments for nonunion of the radial neck have been introduced including conservative management, radial head excision, internal fixation with bone graft and radial head replacement. The choice of treatment for nonunion of the radial neck depends on clinical symptoms and patients’ demands.5,6,8 Radial head excision is an appropriate treatment for radial neck nonunion, especially for older or low demand patients. Ring et al.8 reported five symptomatic patients treated by radial head excision and none of these patients complained of elbow instability or pain after radial head excision. A bone graft with or without internal fixation is usually recommended for younger and high demand patients and most patients treated with an iliac bone graft in the nonunion area obtained solid union and normal strength without any functional disturbance.11 Waters and Stewart 5 also demonstrated satisfactory clinical outcomes after bone grafting in children with radial neck nonunion. In cases of instability and severe bone loss, radial head replacement is considered as a treatment option in terms of the restoration of a mobile, stable and painless elbow.7,12,13 Ozcan et al.7 reported good functional outcome for radial head replacement for the treatment of neglected nonunion.

However, when a patient has asymptomatic nonunion of the radial neck, no further treatment is recommended. Despite a scarcity of literature, asymptomatic patients with nonunion of the radial neck appear to demonstrate satisfactory clinical outcomes after conservative treatment.14,15 Five patients with nonunion of the radial neck showed no functional deficit before radiological diagnosis of nonunion and no additional surgical treatment was necessary for the patient who underwent hardware removal because the elbow was stable with a good range of motion. Furthermore, long-term observations of nonunion patients after conservative treatment demonstrated neither further symptomatic nor radiologic changes, such as, distances between the radial head and capitellum or radial head-shaft angles in four patients. Even two patients who showed further radiologic changes of nonunion gap between radial head and neck, valgus deformity and residual angulation of radial head-shaft, the clinical outcomes of these patients were excellent. Many studies have reported that most cases of nonunion of the radial neck are asymptomatic, but the reason for this has not been clearly established.6-8 The authors found fibrous tissues were filled in nonunion areas with stability during hardware removal. These fibrous tissues might have acted as space occupying structures and importantly contributed to elbow joint stability. Furthermore, the likelihood of this asymptomatic state is undoubtedly enhanced by the non-weight bearing status of the elbow joint.

Conclusions:

Nonunion of the radial neck following the operative treatment of displaced radial head and neck fractures is rare. Despite residual radial head-shaft angle, patients with nonunion following operative treatment demonstrated satisfactory clinical outcomes after conservative treatment at an average follow-up of 7.6 years. When there were no clinical symptoms of radial neck nonunion regardless of radiological findings, no further surgical treatments were recommended

Reference:

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10. Yamaguchi K, Sweet FA, Bindra R, Morrey BF, Gerberman RH. The extraosseous and intraosseous arterial anatomy of the adult elbow. J Bone Joint Surg Am 1997;79:1653-62.
11. Faraj AA, Livesly P, Branfoot T. Nonunion of fracture of the neck of the radius, a report of three cases. J Orthop Trauma 1999;13:513-5.
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13. Faber WA, Verhaar JA. Nonunion of radial neck fracture. An unusual differential diagnosis of tennis elbow: a case report. Acta Orthop Scand 1995;66:176.
14. Cobb TK, Beckenbaugh RD. Nonunion of the radial neck following fracture of the radial head and neck: case reports and a review of the literature. Orthopedics 1998;21:364-8.
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This is a peer reviewed paper 

Please cite as :Ho-Jung Kang : Nonunion of the Radial Neck Following Operative Treatment for Displaced Radial Head and Neck Fractures

J.Orthopaedics 2011;8(1)e10

URL: http://www.jortho.org/2011/8/1/e10

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