Abstract
Background:
We consider dual-plate fixation to improve construct rigidity in cases with fracture complexity. The purpose of this study is to compare the rate of nonunion, prognosis, and complications at 6–12 months for surgically treated acute mid-shaft clavicle fractures when extra-periosteal dual-plate fixation is used in place of the conventional single-plate fixation.
Materials and Methods:
The comparative study was conducted on 47 patients who received acute mid-shaft clavicular fracture treatment in our hospital from March 2015 to July 2018. All patients were divided into dual-plate fixation treatment (group A) and single-plate fixation (group B). Patients undergoing single-plate fixation were compared to dual-plate fixation. Patients were followed up for 6–12 months. Charts were reviewed to assess union rates, prognosis, and complications.
Results:
Forty-seven clavicles (30 single plates and 17 dual plates) were evaluated. All patients (100%) in dual plating group and 128 (93.3%) in single plating group obtained bony union by 1 year. When comparing groups at 3 months, radiographic union was present in 50.0% of single plates and 64.7% in the dual plating group (p = 0.032). However, at 6 months, no significant difference existed (90.0% vs. 94.1%, p = 0.297). Comparing groups at 1.5 and 6 months, Constant–Murley outcome scores were present with no significant difference (p = 0.129, p = 0.054) between single plates and dual plating group. However, at 3 months, significance difference existed.
Discussion:
Three months after the operation, patients with dual-plate fixation showed good functional recovery. Extra-periosteal dual plating for acute mid-shaft clavicle fractures can be safely considered for the treatment of complex acute mid-shaft clavicle fractures without increasing the risk of nonunion or revision.
Conclusions:
Open reduction and internal fixation with an extra-periosteal dual plating technique is a reliable option for treatment of acute mid-shaft clavicle fractures, especially in the setting of severely comminuted fractures and in situations where bone quality is questionable and additional fixation is desired.
Introduction
Clavicle fractures are one of the most common injuries of the shoulder girdle region, with mid-shaft clavicle fractures being especially common, accounting for 10% of all fractures. 1,2 In recent years, research has demonstrated that the rate of nonunion in conservatively treated mid-shaft clavicle fractures may be higher than that has been reported previously. 3 Therefore, operative treatment may be a preferable alternative to conservative treatment, as surgical intervention results in both high rates of union and patient satisfaction in cases of mid-shaft clavicular fracture with substantial displacement and shortening. 4,5 The clavicle exhibits considerable movement in all three planes of motion, and so rigid fixation can be challenging when attempting fracture osteosynthesis. Surgical intervention may be complicated by nonunion, implant failure, or both. One known risk factor for nonunion is inadequate fracture fixation, which may lead to excess motion at the fracture site. Fracture site displacement of more than 20 mm increases the risk of nonunion. 6 The risk of symptomatic malunion is also prevalent in clavicle fractures with more than 20 mm of displacement. 7 Surgeons may consider dual-plate fixation to improve construct rigidity in cases with fracture complexity. In clinical practice, various operative solutions have been proposed, ranging from intramedullary pinning with Kirschner wires 8 and utilization of cannulated screws, 9 to compression plates and precontoured clavicle locking plate fixations, 10 as well as external fixation. 11
The purpose of this study was to compare the rates of nonunion, prognosis, and complications at 6–12 months for surgically treated acute mid-shaft clavicle fractures when extra-periosteal dual-plate fixation was used in place of conventional single-plate fixation.
Materials and methods
Clinical series
This comparative study was conducted on 47 patients who received comminuted mid-shaft clavicular fracture treatment at our hospital from March 2015 to July 2018. This study was approved by our Institutional Review Board. The study included patients aged 20–65 years. The inclusion criteria for this study were (a) comminuted mid-shaft clavicle fractures, (b) Arbeitsgemeinschaftfür Osteosynthesefragen/Orthopaedic Trauma Association (AO/OTA) classification: 15-B2, 15-B3, (c) internal fixation with dual plates or internal fixation with single plate, and (c) normal shoulder function before injury. The exclusion criteria included (1) proximal or distal fracture, (2) skeletal immaturity, (3) open fracture, (4) pathological fracture, (4) neurovascular injury, (5) severe craniocerebral injury, (6) endotracheal intubation, and (7) or other injuries that involved shoulder girdle or ipsilateral extremity, chest injuries, and injuries that could not be treated surgically within 7 days. All 47 patients were divided into 2 groups according to the treatment methods: 17 patients (12 males and 5 females) with isolated mid-shaft clavicle fractures were treated with dual-plate fixation (group A). The average patient age at the time of injury was 39.29 ± 13.57 years. Ten cases involved the right clavicle and seven cases involved the left. Two cases were caused by fall injuries, nine due to impact injuries, and six as a result of club injuries. The time from admission to surgery ranged from a minimum of 20 h to a maximum of 4 days, with an average of 2.58 ± 0.81 days, and 30 patients (17 males and 13 females) with isolated mid-shaft clavicle fractures were treated with single-plate fixation (group B). The average patient age at the time of injury was 37.00 ± 12.18 years. Sixteen cases involved the right clavicle and 14 cases involved the left. Six cases were caused by fall injuries, 15 due to impact injuries, and 9 as a result of club injuries. The time from admission to surgery ranged from a minimum of 18 h to a maximum of 4 days, with an average of 2.30 ± 0.59 days. Before surgery, it is important to perform computed tomography with 3D reconstruction and radiographic evaluation. These studies can aid the surgeon in understanding more complex fracture patterns and assist in deciding whether significant comminution exists.
Surgical technique
Both the dual-plate fixation treatment (group A) and the single-plate fixation (group B) patients were positioned in a beach-chair orientation on the surgical table. This position is convenient for the examination of the fracture and reduction by fluoroscopy.
A 7- to 8-cm longitudinal incision can then be made along the anterosuperior border of the clavicle. The skin, subcutaneous tissue, and fascia were all dissected. Decompression of the fascia was then performed. Next, the dislocated fracture end in the middle of the clavicle was identified and cleaned of any intervening soft tissue or early healing, and the fracture was then reduced.
In group A, a 3.5-mm locking compression plate (LCP) or reconstruction plate was applied to the superior surface of the midshaft, while a small “aid plate” was applied to span the fracture. The small “aid plate” could then be applied superiorly or anteriorly. However, results of the biomechanical phase of the study demonstrate that the dual plating construct was more rigid than a single locked anterior plate, but less rigid than a single locked superior plate. 12 Therefore, we prefer anterior-based neutralization plates because of decreased hardware prominence and improved fixation in the anterior–posterior plane of the clavicle. In group B, a 3.5-mm LCP was applied in the same configuration as group A. Standard 3.5-mm bicortical screws were inserted in the center of the holes, symmetric to the fracture site.
During the operation, a C-arm fluoroscopy machine was used to check the fracture position, ensure proper screw length, and, for more distal fractures, ensure that we had not penetrated the acromioclavicular joint. The wound was then copiously irrigated and sutured in layers, then protected with a sterile gauze compression bandage. After resting in a sling for approximately 2 weeks, the affected limb could be used for basic functional rehabilitation exercise.
Statistical analysis
Patients were divided into two groups based on the use of single-plate fixation (single-plate group) versus dual-plate fixation (dual-plate group). Statistical analysis was performed using SPSS software (version 18.0, SPSS, Chicago, Illinois, USA). Standard statistical analysis was performed with the assistance of a statistician. Student’s t-test, a χ 2 test, and Fisher’s exact test were performed in the analysis to compare time to union, Constant–Murley outcome score, and bony union between the two groups. All tests were two sided, and the level of significance was set at α < 0.05.
Results
A summary is provided in Table 1, demonstrating demographics, the mechanism of injury, plate construction, and follow-up data for each patient in this series. In the single-plate group, 30 clavicles were fixed with locking plates. All plates were placed on the anteroinferior aspect of the clavicle. In the dual-plate group, 17 clavicles were fixed using locking, reconstruction, and aid plates. In the dual-plate group, all patients were treated with the main plate in the superior position, with a smaller aid plate fixed anteriorly (Figures 1 and 2).
Clinical results of mid-shaft clavicle fractures.

Forty-year-old male who sustained an electrombile crash with an AO/OTA 15-B3 clavicle fracture (a) who underwent dual-plate fixation with a locking plate superiorly and aid plate anteriorly (b to d).

Fifty-year-old male with an AO/OTA-B3 clavicle fracture treated with a reconstruction plate superiorly and aid plate anteriorly.
Four patients (8.5%) showed no bridging callus on plain radiographs at 6 months but went on to achieve union by 1 year, without further intervention. Two patients (4.3%) showed persistent radiographic nonunion at 1 year. Of the 2 nonunions, one developed implant failure and one had a stable implant with radiographic nonunion. In the dual-plate group, all 30 patients achieved bony union within 6 months. When comparing the groups at 3 months, radiographic union was present in 50.0% of patients with single plates and 64.7% of those with dual plates (p = 0.032). However, at 6 months, no significant difference existed (90.0% vs. 94.1%, p = 0.297; Table 1). Thirty patients in the single-plate group and 17 in the dual-plate group were followed up for an average of 9 (9.73 ± 3.19) and 11 (11.29 ± 3.96) months, respectively, and were then assessed clinically. Dual-plate fixation was used most commonly in OTA 15-B2 and 15-B3 fractures; therefore, we identified 47 patients with OTA 15-B2 and 15-B3 acute mid-shaft clavicle fractures who were treated with open reduction and internal fixation. No differences were found between single- and dual-plate fixation (p = 0.683). In addition, the union rate within 3 and 6 months showed no significant difference between AO/OTA 15-B2 and 15-B3. All patients completed the Constant–Murley 13 surveys; these include a pain module, a work module, and a sports module, where applicable, at the 6-month follow-up. The Constant–Murley scores are measured on a scale from 1 to 100, with higher scores suggestive of better function. Two patients who were followed up until pain-free union was achieved were not available to complete the surveys. In the single-plate group, the average scores at 1.5 months, 3 months, and 6 months were 74.90 ± 5.32, 81.10 ± 4.15, and 89.57 ± 2.39, respectively. In the dual-plate group, the average scores at 1.5 months, 3 months, and 6 months were 77.53 ± 6.09, 85.47 ± 4.54, and 91.18 ± 3.13, respectively. While a significant difference was demonstrated at 3 months (p = 0.002; Table 1), when comparing groups at 1.5 versus 6 months, no significant difference existed in the Constant–Murley outcome scores (p = 0.129, p = 0.054, respectively) between the single-plate and the dual-plate groups.
Discussion
The most common injury mechanism of mid-clavicle fracture is a direct blow to the shoulder. When the shoulder joint is subjected to an impact force from the side, the shoulder joint and clavicle absorb the bulk of the applied force. Given that the middle clavicle is the narrowest region and has the least soft tissue coverage, about 85% of clavicle fractures occur in the middle clavicle. 14 In the past, because of the excellent remodeling properties of the clavicle, comminuted fracture in the middle clavicle were generally treated conservatively, regardless of fracture displacement or comminution. However, recent studies have shown that the incidence of bone failure is significantly higher after conservative treatment than if the fracture was treated surgically. 5
Extra-periosteal dual plating for acute mid-shaft clavicle fractures can be safely considered for the treatment of complex acute mid-shaft clavicle fractures without increasing the risk of nonunion or revision. The increased soft tissue exposure for the addition of the second plate did not require any stripping of the periosteum in an attempt to retain native blood supply. Union rates of 93.3% in the single-plate and 100% in the dual-plate groups compare favorably to the current literature for surgically treated acute mid-shaft clavicle fractures, where union rates of 91.1% and 100% have been reported. 15 Union was significantly greater at 3 months in the single-plate group as compared to the dual-plate group, but no difference remained at 6 months. 16 In our clinical series, comparing two groups at 1.5 and 6 months, no significant differences existed in the Constant–Murley outcome scores (p = 0.129, p = 0.054) between the single-plate and dual-plate groups. However, at 3 months, a significant difference existed (p = 0.002). Three months after the operation, patients with dual-plate fixation showed good functional recovery.
The application of a reconstruction plate combined with an anterior microplate in the extra-periosteal tissue above the clavicle can reduce the risk of damaging the blood supply local to the fracture end and avoid bone failure to the greatest extent possible. A reconstructive steel plate combined with a micro steel plate can resist multi-planar bending stress and axial rotation stress, as well as lateral shear force load simultaneously, reducing the axial stress absorbed by surgical screws, and reducing the effect of stress shielding, resulting in a more stable repair. 17 When analyzing fractures by AO-OTA classification, there was no difference in time to union between subgroups treated with single- versus dual-plate fixation. The dual-plate fixation group represents a subset of patients who demonstrated more complex and challenging fractures intraoperatively. In some cases, these patients were even allowed to weight-bear through their operative extremity due to the need to mobilize in the setting of polytrauma. 18 Despite the increased fracture complexity, dual plating is still compared favorably to single-plate fixation with regard to nonunion and revision. As mentioned above, there was no standardization of implants, but previous studies have demonstrated both reconstruction and locking plates achieve acceptable bony union and clinical outcomes. 19,20 Chen et al. 16 noted concern with respect to implant prominence, and so the authors tended to place the mini aid plate superiorly and the large neutralization plate anteriorly. In this pursuit, our study may require further development.
Conclusion
Both methods achieved good results in the treatment of comminuted mid-shaft clavicle fractures; however, open reduction and internal fixation with an extra-periosteal dual plating technique is a reliable option for treatment of comminuted mid-shaft clavicle fractures, especially in the setting of severely comminuted fractures and in situations where bone quality is questionable and additional fixation is desired.
Footnotes
Declaration of conflicting interests
The author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.
Ethical approval
This article does contain human participants operated on by one of the authors.
Funding
The author(s) received no financial support for the research, authorship, and/or publication of this article.
Informed consent
Informed consent was obtained from all individual participants included in the study prior to surgery.
