Implant removal after clavicle plating is common. Low-profile dual mini-fragment plate constructs are considered safe for fixation of diaphyseal clavicle fractures. The aim of this study was to investigate: (1) the biomechanical competence of different dual plate designs from stiffness and cycles to failure, and (2) to compare them against 3.5mm single superoanterior plating. Twelve artificial clavicles were assigned to 2 groups and instrumented with titanium matrix mandible plates as follows: group 1 (G1) (2.5mm anterior+2.0mm superior) and group 2 (G2) (2.0mm anterior+2.0mm superior). An unstable clavicle shaft fracture (AO/OTA15.2C) was simulated. Specimens were cyclically tested to failure under craniocaudal cantilever bending, superimposed with torsion around the shaft axis and compared to previous published data of 6 locked superoanterior plates tested under the same conditions (G3). Displacement (mm) after 5000 cycles was highest in G3 (10.7±0.8) followed by G2 (8.5±1.0) and G1 (7.5±1.0), respectively. Both outcomes were significantly higher in G3 as compared to both G1 and G2 (p≤0.027). Cycles to failure were highest in G3 (19536±3586) followed by G1 (15834±3492) and G2 (11104±3177), being significantly higher in G3 compared to G2 (p=0.004). Failure was breakage of one or two plates at the level of the osteotomy in all specimens. One G1 specimen demonstrated failure of the anterior plate. Both plates in other G1 specimens. Majority of G2 had fractures in both plates. No screw pullout or additional clavicle fractures were observed among specimens. Low-profile 2.0/2.0 dual plates demonstrated similar initial stiffness compared to 3.5mm single plates, however, had significantly lower failure endurance. Low-profile 2.5/2.0 dual plates showed significant higher initial stiffness and similar resistance to failure compared to 3.5mm single locked plates and can be considered as a useful alternative for diaphyseal clavicle fracture fixation. These results complement the promising results of several clinical studies

Recently, a new generation of superior clavicle plates was developed featuring the variable-angle locking technology for enhanced screw positioning and optimized plate-to-bone fit design. On the other hand, mini-fragment plates used in dual plating mode have demonstrated promising clinical results. However, these two bone-implant constructs have not been investigated biomechanically in a human cadaveric model. Therefore, the aim of the current study was to compare the biomechanical competence of single superior plating using the new generation plate versus dual plating with low-profile mini-fragment plates. Sixteen paired human cadaveric clavicles were assigned pairwise to two groups for instrumentation with either a 2.7 mm Variable Angle Locking Compression Plate placed superiorly (Group 1), or with one 2.5 mm anterior plate combined with one 2.0 mm superior matrix mandible plate (Group 2). An unstable clavicle shaft fracture AO/OTA15.2C was simulated by means of a 5 mm osteotomy gap. All specimens were cyclically tested to failure under craniocaudal cantilever bending, superimposed with bidirectional torsion around the shaft axis and monitored via motion tracking. Initial stiffness was significantly higher in Group 2 (9.28±4.40 N/mm) compared to Group 1 (3.68±1.08 N/mm), p=0.003. The amplitudes of interfragmentary motions in terms of craniocaudal and shear displacement, fracture gap opening and torsion were significantly bigger over the course of 12500 cycles in Group 1 compared to Group 2; p≤0.038. Cycles to 2 mm shear displacement were significantly lower in Group 1 (22792±4346) compared to Group 2 (27437±1877), p=0.047. From a biomechanical perspective, low-profile 2.5/2.0 dual plates demonstrated significantly higher initial stiffness, less interfragmentary movements, and higher resistance to failure compared to 2.7 single superior variable-angle locking plates and can therefore be considered as a useful alternative for diaphyseal clavicle fracture fixation especially in unstable fracture configurations

Abstract. Objectives. Clavicle fractures are common, yet debate exists regarding which patients would benefit from conservative versus operative management. Traditionally shortening greater than 2cm has been accepted as an indicator for surgery. However, clavicle length varies between individuals. In a cadaveric study clavicle shortening greater than 15% was suggested to affect outcomes. There is no clinical correlation of this in the literature. In this study we investigate outcomes following middle third clavicle fractures and the effect of percentage shortening on union rates. Methods. We identified a consecutive series of adults with primary midshaft clavicle fractures presenting to our institution from April 2015-March 2017. Clinical records and radiographs were reviewed to elicit outcomes. Time to union was measured against factors including; percentage shortening, displacement, comminution and smoking. Statistical significance was calculated. Results. 127 patients were identified, of whom 90 were managed conservatively and 37 operatively. Fractures were displaced in 86 patients (68%). Mean age was 41.7 years (range 18–89). Mean time to union for displaced fractures was longer than for undisplaced at 13.4 and 8.9 weeks respectively (p=0.0948). Displaced fractures treated operatively had mean time to union of 12.8 weeks, three weeks shorter than those managed conservatively (p=0.0470). Mean time to union for fractures with >15% shortening was 16.0 weeks, nearly double the 8.7 weeks with <15% shortening (p= 0.0241). Smokers had 8 weeks longer time to union (p=0.0082). Nonunion rate was 10% in fractures managed conservatively and 0% in those treated operatively. Complications following operative management were plate removal (13.5%), frozen shoulder (8.1%) and infection (2.9%). Conclusions. Nonunion rate is higher in fractures managed conservatively. Shortening >15% leads to significantly longer union time and should therefore be used as an indicator for surgery. Displacement and smoking also lengthen time to union and should be considered in the operative decision process. Declaration of Interest. (b) declare that there is no conflict of interest that could be perceived as prejudicing the impartiality of the research reported:I declare that there is no conflict of interest that could be perceived as prejudicing the impartiality of the research project

Background. Clavicle development occurs before the age of 9 in females and 12 in males. Children below the age of 10 with displaced midshaft clavicle fractures recover well with conservative management. However adolescents are more demanding of function and satisfaction following clavicle fractures and may benefit from operative management. Study aims: 1) Perform a systematic review of the current evidence supporting intramedullary fixation of adolescent clavicle fractures. 2) Review current management in a major trauma center (MTC) with a view to assess feasibility for a randomised controlled trial (RCT). Methods. The MEDLINE, EMBASE and AMED databases were searched in October 2014 to identify all English language studies evaluating intramedullary fixation in children aged 10–18 years using MeSH terms. Data was extracted using a standardised data collection sheet and studies were critically appraised by aid of the PRISMA checklist. All patients aged 9–15 attending an MTC receiving clavicle radiographs in 2014 were retrospectively reviewed for type of fracture, management and outcome. Results. Literature search identified 54 articles. After application of exclusion criteria 3 studies were selected for final review. 47 adolescent patients received intramedullary clavicle fixation from a prospective and two retrospective case series. 61 adolescents presented to our unit with a clavicle fracture in 2014, 2 were lost to follow-up, 54 were managed non-operatively, 3 received titanium-elastic nailing, 1 plate osteosynthesis and 1 bone suture. 0 and 19 patients reported a palpable lump, mean time to pain resolution was 4 and 6 weeks and time to full range of motion was 4 and 5 weeks following operative and conservative management respectively. All patients reached radiographic union. Conclusion. Current evidence supporting intramedullary fixation of clavicle fractures in adolescents is poor. There remains clinical equipoise on the best management of these patients, however they are predominantly treated conservatively. A future multi-center RCT may be feasible. Level of Evidence. 1

Abstract. Objectives. We aimed to evaluate if union of clavicle fractures can be predicted at six weeks post-injury by the presence of bridging callus detected by ultrasound. Methods. Adult patients who sustained a displaced midshaft clavicle were recruited prospectively. We assessed patient demographics, functional scores and radiographic predictors with a standardized protocol at six weeks. Ultrasound evaluation of the fracture site was undertaken to determine if sonographic bridging callus was present. Nonunion was determined by CT scanning at six months post-injury. Clinical features at six weeks were used to stratify patients at high risk of nonunion and a QuickDASH ≥40, fracture movement on examination or absence of callus on radiograph. Results. 112 patients completed follow-up at six months with a nonunion incidence of 17% (n=18/112). Sonographic bridging callus was detected in 62.5% (n=70/112) of the cohort at six weeks post-injury. If present, union occurred in 98.6% of the fractures (n=69/70). If absent, nonunion developed in 40.5% of cases (n=17/42). The sensitivity to predict union with sonographic bridging callus at six weeks was 73.4% and the specificity was 94.4%. Regression analysis found failure to detect sonographic bridging callus at six weeks was associated with nonunion, older age, female sex, and greater overall fracture displacement (Nagelkerke R2=0.60). Of the cohort, 30.4% (n=34/112) had absent sonographic bridging callus at six weeks in combination with one or more of the ‘high risk’ clinical features. If one was present the nonunion rate was 47.1%, increasing to 60% with two risk factors and 100% when combined with all three. Conclusions. Ultrasound can accurately predict fracture healing at six weeks following a displaced midshaft clavicle fracture. When combined with poor clinical recovery this could be used to target patients for early operative intervention. Declaration of Interest. (b) declare that there is no conflict of interest that could be perceived as prejudicing the impartiality of the research reported:I declare that there is no conflict of interest that could be perceived as prejudicing the impartiality of the research project

Last decade, a shift towards operative treatment of midshaft clavicle fractures has been observed [T. Huttunen et al., Injury, 2013]. Current fracture fixation plates are however suboptimal, leading to reoperation rates up to 53% [J. G. Wijdicks et al., Arch. Orthop. Trauma Surg, 2012]. Plate irritation, potentially caused by a bad geometric fit and plate prominence, has been found to be the most important factor for reoperation [B. D. Ashman et a.l, Injury, 2014]. Therefore, thin plate implants that do not interfere with muscle attachment sites (MAS) would be beneficial in reducing plate irritation. However, little is known about the clavicle MAS variation. The goal of this study was therefore to assess their variability by morphing the MAS to an average clavicle. 14 Cadaveric clavicles were dissected by a medical doctor (MH), laser scanned (Nikon, LC60dx) and a photogrammetry was created with Agisoft photoscan (Agisoft, Russia). Subsequently a CT-scan of these bones was acquired and segmented in Mimics (Materialise, Belgium). The segmented bone was aligned with the laser scan and MAS were indicated in 3-matic (Materialise, Belgium). Next, a statistical shape model (SSM) of the 14 segmented clavicles was created. The average clavicle from the SSM was then registered to all original clavicle meshes. This registration assures correspondences between source and target mesh. Hence, MAS of individual muscles of all 14 bones were indicated on the average clavicle. Mean area is 602 mm. 2. ± 137 mm. 2. for the deltoid muscle, 1022 mm. 2. ±207 mm. 2. for the trapezius muscle, and 683 mm. 2. ± 132 mm. 2. for the pectoralis major muscle. The sternocleidomastoid muscle has a mean area of 513 mm. 2. ± 190 mm. 2. and the subclavius muscle had the smallest mean area of 451 mm. 2. ± 162 mm. 2. Visualization of all MAS on the average clavicle resulted in 72% coverage of the surface, visualizing only each muscle's largest MAS led to 52% coverage. The large differences in MAS surface areas, as shown by the standard deviation, already indicate their variability. Difference between coverage by all MAS and only the largest, shows that MAS location varies strongly as well. Therefore, design of generic plates that do not interfere with individual MAS is challenging. Hence, patient-specific clavicle fracture fixation plates should be considered to minimally interfere with MAS

In an osteological collection of 3100 specimens, 70 were found with unilateral clavicular fractures which were matched with 70 randomly selected normal specimens. This formed the basis of a study of the incidence of arthritis of the acromioclavicular joint and the effect of clavicular fracture on the development of arthritis in the ipsilateral acromioclavicular joint. This was graded visually on a severity scale of 0 to 3. The incidence of moderate to severe arthritis of the acromioclavicular joint in normal specimens was 77% (100 specimens). In those with a clavicular fracture, 66 of 70 (94%) had arthritis of the acromioclavicular joint, compared to 63 of 70 (90%) on the non-injured contralateral side (p = 0.35).

Clavicles with shortening of 15 mm or less had no difference in the incidence of arthritis compared to those with shortening greater than 15 mm (p = 0.25). The location of the fracture had no effect on the development of arthritis.