For displaced clavicular fractures, plate fixation improves clinical outcomes and patient satisfaction as compared to nonoperative treatment [[
1]–[
4]]. However, plate fixation is related to implant prominence and skin irritation and has previously resulted in implant removal rates of 9% to 64% [[
3]-[
6]]. A recent systematic review of eleven studies showed that nonunion rates after plate fixation were less than 10% in all except one study [[
6]]. Although clavicle fixation has been controversial regarding its use and plate location, recent studies have shown efficient healing, few complications, and excellent return to function for anteroinferior plating [[
7]–[
9]]. Advantages of this technique are avoidance of potentially dangerous infraclavicular structures and reduction of patient complaints due to implant prominence [[
7]].
Regarding stability, a recent biomechanical study showed inferior nonlocking plates to be stiffer than superior locking plates [[
10]]. In addition, a finite element study showed that anteroinferior plating best resists the effect of most daily living forces acting on the clavicle and can be considered more mechanically physiological [[
11]]. The anteroinferior plate is perpendicular to the primary force vector and has greater resistance to axial compression of the clavicle during motions of abduction and flexion [[
10]]. Taking these mechanical findings into consideration and following the effort to reduce implant prominence, anteroinferior plating has been performed using 2.7-mm plates [[
7],[
12]].
Two biomechanical studies have found greater stability with compression plates as compared to reconstruction plates [[
13],[
14]]. Thus, the primary purpose of this study was to evaluate the rates of fracture union, nonunion, malunion, implant failure, and implant removal with regards to plate type (compression plates vs. reconstruction plates) in midshaft clavicle fractures fixed with 2.7-mm anteroinferior plates utilizing modern plating techniques.
Patients and methods
This study was an Institutional Review Board (IRB)-approved retrospective exploratory cohort review of operatively treated midshaft clavicle fractures at a single large private practice associated with a level I teaching trauma center. Consecutive patients were identified by Current Procedural Terminology (CPT) coding for operative (23515) and nonoperative (23500 and 23505) treatment of diaphyseal clavicle fracture that had initial treatment from 1 March 2002 through 31 March 2012. A total of 718 clavicle fractures were diagnosed and treated during this time period. Operative criteria included significant clavicular shortening (greater than 20 mm on either AP, cephalad, or caudal radiographs), associated neurological injury, associated unstable scapular injury (glenoid neck, acromion, coracoid, or intra-articular glenoid fractures), double suspensory shoulder instability, open clavicular fractures, published criteria for displacement, skin compromise, or polytrauma [[
1],[
2],[
15]–[
17]]. Inclusion criteria were skeletally mature (age equal to or greater than 18 years), diaphyseal clavicle fracture that met operative indications, open reduction internal fixation (ORIF) via an anterior-inferior approach, internal fixation with 2.7-mm plate and screws, and a minimum 3 months follow-up confirming radiographic union and return to previous activities and/or employment was established. A minimum follow-up was chosen based on a previous study which showed patients with early fracture healing returned to previous activities at the 3-month interval and skin or soft tissue irritation, fixation failure, or nonunion were also commonly noted by 3 months [[
12]]. A total of 249 midshaft diaphyseal clavicular fractures fulfilled the inclusion criteria. Ninety-three fractures were excluded due to pathological fracture (1), death due to other injuries (1), initial nonoperative treatment with subsequent nonunion (3), lost to follow-up (6), insufficient records/radiographs (17), and follow-up less than 3 months (65). One hundred fifty-six fractures (156) in 155 patients formed the basis of the study.
Patient demographics for all fractures and primary outcomes are displayed in Table
1. Fractures occurred in 41% on the right and in 59% on the left hand side. The mean follow-up was 8.9 months (3 to 54). Fractures were caused by a high-energy mechanism in 92.3% of patients (Table
2). Three fractures were classified as open (one type I and two type II according to Gustilo/Anderson). Associated injuries were found in 82 of the 156 patients (52.6%). Musculoskeletal injuries included 35 ipsilateral shoulder girdle extremity fractures (22.4%), 25 scapula fractures (16.0%), 17 rib fractures (10.9%), and 3 proximal humeral fractures (1.9%).
Table 1
Patient demographics by plate type and primary outcomes
All fractures | n = 71 | n = 85 | |
Age | 39 ± 15 | 41 ± 15 | 0.431 |
Sex | | | 0.071 |
Male | 43, 60.6% | 63, 74.1% | |
Female | 28, 39.4% | 22, 25.9% | |
BMI (kg/m2) | 25.5 ± 4.9 | 25.9 ± 5.1 | 0.730 |
Current smoker | 19, 26.8% | 19, 22.4% | 0.523 |
United fractures | n = 65 | n = 84 | |
Age | 39 ± 15 | 41 ± 15 | 0.380 |
Sex | | | 0.160 |
Male | 41, 63.1% | 62, 73.8% | |
Female | 24, 36.9% | 22, 26.2% | |
BMI (kg/m2) | 25.6 ± 4.9 | 25.8 ± 5.1 | 0.829 |
Current smoker | 16, 24.6% | 18, 21.4% | 0.646 |
Nonunion | n = 5 | n = 1 | |
Age | 42 ± 15 | 32 | 0.566 |
Sex | | | 0.121 |
Male | 1, 20% | 1, 100% | |
Female | 4, 80% | 0 | |
BMI (kg/m2) | 25.2 ± 4.3 | 32.1 | |
Current smoker | 3, 60 % | 1, 100% | 0.667 |
Malunion | n = 2 | n = 0 | |
Age | 32 ± 4 | | UA |
Sex | | | UA |
Male | 2, 100% | | |
Female | 0 | | |
BMI (kg/m2) | 41.3 | | UA |
Current smoker | 0 | | UA |
Implant failure | n = 6 | n = 1 | |
Age | 38 ± 15 | 19 | 0.316 |
Sex | | | 0.571 |
Male | 3, 50% | 1, 100% | |
Female | 3, 50% | 0 | |
BMI (kg/m2) | 28.7 ± 8.1 | 19.2 | 0.348 |
Current smoker | 3, 50% | 0 | 0.571 |
Table 2
Mechanism of injury
High energy | | |
Motor cycle accident (MCA) | 45 | 28.9 |
Motor vehicle accident (MVA) | 37 | 23.7 |
Fall | 21 | 13.5 |
All-terrain vehicle, snowmobile, or watercraft | 20 | 12.8 |
Bicycling | 13 | 8.3 |
Sports | 6 | 3.8 |
Pedestrian versus car | 2 | 1.3 |
Low-energy fall | 9 | 5.8 |
Others | 3 | 1.9 |
All patients were treated by four fellowship trained orthopedic trauma surgeons utilizing similar philosophies and modern techniques of plate fixation [[
12]]. Patients were evaluated at regular intervals of 2, 6, 12 weeks, and ongoing according to clinical necessity including, but not limited to, pain, plate irritation, plate prominence, or not achieving complete clinical healing. The attending surgeon was responsible for clinically assessing the patient, interpreting radiographs, and determining primary healing outcomes. Pain was recorded utilizing the visual analog scale from a standardized questionnaire that the patient filled out at scheduled office visits [[
18]]. Range of motion (ROM) using basic clinical measurements was recorded. Radiographs consisted of cephalad and caudal views obtained at each interval [[
19]]. Clavicular displacement was measured using digital software with picture archiving and communication system (PACS) or manually using protractors. Injury patterns were classified according to OTA/AO (Orthopaedic Trauma Association/Arbeitsgemeinschaft fur Osteosynthesefragen) classification [[
20]]. Based on reported clavicle union rates at 10 to 16 weeks following operative fixation [[
3],[
7],[
12],[
21]], a nonunion was defined as a painful, persistent fracture line with no radiographic progression of healing over three consecutive months with or without fixation failure which required surgical revision. A malunion was defined as a fracture that achieved a malpositioned bony union stable from the initial reduction and fixation or a reduction that changed with time. Any change in implant position or alignment regardless of union seen on serial radiographs was deemed an implant failure.
Statistical analysis was completed using PASW® version 18 (IBM, Armonk, NY, USA). Descriptive statistics provided percent, range, mean, and median. Chi-square test was used to determine associations based on plate type; Fisher’s exact test, to determine comparisons when small ordinal groups existed such as with tobacco use and malunion; Mann–Whitney U test, to calculate the comparisons for plate length, working length, lag screws, and cortical screws; and Kruskall-Wallis, to calculate comparisons for OTA/AO classification. Spearman’s rho determined correlation between pain and complications. Significance was set at less than 0.05.