Superior versus anteroinferior plating of the clavicle: a finite element study

Effect of Sextant Fixating Angle of Spiral Clavicle Plate on Biomechanical Stability-A Preliminary Finite Element Study

INTRODUCTION

A spiral clavicle plate has been accepted for its superior multidirectional compatibility in the treatment of midshaft clavicle fractures from a biomechanical perspective. However, the influence of the sextant angle (spiral level) definition on biomechanical performance has not been clarified. A conceptual finite element analysis was conducted to identify the advantages and drawbacks of spiral clavicle plates with various sextant angle definitions.

METHODS

Conventional superior and three different conceptual spiral plates with sextant angle definitions ranging from 45 to 135 degrees were constructed to restore an OTA 15-B1.3 midshaft clavicle fracture model. Three major loading scenarios (cantilever downward bending, axial compression, and axial torsion) were simulated to evaluate the reconstructed structural stiffness and the stress on the clavicle plate and bone screws.

RESULTS

The spiral clavicle plate demonstrated greater capability in resisting cantilever downward bending with an increase in sextant angle and showed comparable structural stiffness and implant stress compared to the superior clavicle plate. However, weakened resistance to axial compression load was noted for the spiral clavicle plate, with lowered stiffness and increased stress on the clavicle plate and screws as the spiral level increased.

CONCLUSION

The spiral clavicle plate has been reported to offer multidirectional compatibility for the treatment of midshaft clavicle fractures, as well as geometric advantages in anatomical matching and reduced skin prominence after surgery. The current study supports that remarkable cantilever bending strength can be achieved with this plate. However, users must consider the potential drawback of lowered axial compression resistance in safety considerations.

Low rate of secondary surgery and implant removal following superior, precontoured plating of midshaft clavicle fractures

Background

Surgical fixation of midshaft clavicle fractures with a single 3.5 mm superior clavicular plate has been associated with a high rate of hardware removal due to symptomatic hardware. Because of this, dual-plating techniques with lower-profile implants have been proposed. However, dual-plating systems have disadvantages, including increased cost and increased surgical morbidity. The aim of this study was to define the rate of symptomatic hardware removal for all midshaft clavicle fractures.

Methods

We retrospectively reviewed information on all patients from 2014 to 2018 at a single level 1 trauma institution with surgeries performed by two fellowship-trained orthopedic trauma surgeons. Documented removal of hardware and the reason for removal were recorded. We then contacted all patients at their listed telephone number to confirm the hardware was still in place and to administer patient outcome questionnaires. If patients did not answer, attempts were made to contact them multiple times on multiple days. Those who were not reached but had documented hardware removal were included in the total number of patients with hardware removal.

Results

The search revealed 158 patients, of whom 89 (61.8%) were included in the study. Average follow up was 4.09 years (range 2.02-6.50 years). Five patients (5.56%) underwent hardware removal. Removal was for symptomatic or irritating hardware in two of these patients (2.22%). Average abbreviated Disability of Arm, Shoulder, and Hand score was 6.27, and average American Society of Shoulder and Elbow Surgeons shoulder score was 93.6.

Conclusion

In our series, the rate of symptomatic hardware removal was 2.22%, well below reported removal rates. Hardware removal rates for prominent symptomatic superior clavicular plates may be significantly lower than previously reported, and these fractures may be adequately treated with a single, superior plate.

Anteroinferior plating is an independent factor for decreasing symptomatic implant removal rates after plate fixation for midshaft clavicle fractures

Objectives

The factors that significantly influence the symptomatic implant removal rates after plate fixation for midshaft clavicle fractures remain controversial. The purpose of this study was to compare the symptomatic implant removal rates between 2 different types of plating technique and to evaluate independently associated factors.

Design

Retrospective cohort study.

Setting

Acute care center.

Patients/Participants

A total of 71 patients 16 years or older who were diagnosed with displaced midshaft clavicle fractures from April 2016 to March 2020.

Intervention

Thirty-nine patients were treated with superior plating (Group SP), and the remaining 32 patients were treated with anteroinferior plating (Group AIP).

Main Outcome Measurements

Symptomatic implant removal rates after plate fixation for midshaft clavicle fractures.

Results

Symptomatic implant removal rates were significantly lower in Group AIP (28.1%) than in Group SP (53.8%) (P = 0.033). Multivariate analyses showed that symptomatic implant removal rates were significantly decreased by three independent factors, namely AIP (odds ratio [OR] = 0.323) (P = 0.037), greater age (45 years or older) (OR = 0.312) (P = 0.029), and high body mass index (≥25 kg/m²) (OR = 0.117) (P = 0.034).

Conclusions

AIP significantly and independently decreased the symptomatic implant removal rate. Among the three explanatory factors showing significant difference, plating technique is the only factor that can be altered by medical institutions. Therefore, we recommend this technique for displaced midshaft clavicle fractures to reduce a second surgery such as symptomatic implant removal.

Level of Evidence

Level 3, retrospective cohort study.

A Validated Open-Source Shoulder Finite Element Model and Investigation of the Effect of Analysis Precision

Understanding the loads and stresses on different tissues within the shoulder complex is crucial for preventing joint injury and developing shoulder implants. Finite element (FE) models of the shoulder joint can be helpful in describing these forces and the biomechanics of the joint. Currently, there are no validated FE models of the intact shoulder available in the public domain. This study aimed to develop and validate a shoulder FE model, then make the model available to the orthopaedic research community. Publicly available medical images of the Visible Human Project male subject's right shoulder were used to generate the model geometry. Material properties from the literature were applied to the different tissues. The model simulated abduction in the scapular plane. Simulated glenohumeral (GH) contact force was compared to in vivo data from the literature, then further compared to other in vitro experimental studies. Output variable results were within one standard deviation of the mean in vivo experimental values of the GH contact force in 0°, 10°, 20°, 30°, and 45° of abduction. Furthermore, a comparison among different analysis precision in the Abaqus/Explicit platform was made. The complete shoulder model is available for download at github.com/OSEL-DAM/ShoulderFiniteElementModel.

Management of Displaced Midshaft Clavicle Fractures in Pediatrics and Adolescents: Operative vs Nonoperative Treatment

The purpose of the current review is to describe the management of displaced midshaft clavicle fractures in pediatric and adolescent patients. Midshaft clavicle fractures are relatively common in pediatric and adolescent patients. They most commonly occur from direct trauma and are often related to sports participation in adolescents. Recent literature in the management of adult midshaft clavicle fractures has supported operative management due to improved functional outcomes, decreased time to union, leading to early return to activity. A similar trend of increasing frequency in operative management has been seen in pediatric and adolescent patients with no consensus in the literature on optimal management. Nonoperative treatment consists of with a brief period of sling immobilization followed by range of motion. Operative management may be considered for open fractures, fractures with significant neurovascular compromise and soft tissue complications. Studies have shown comparable mid- to long-term functional and patient-reported outcomes after operative and nonoperative management of midshaft clavicle fractures in pediatric patients.

The anterior head of deltoid in relation to anterior clavicle plating: how much are we releasing?

Middle to distal-third clavicular shaft fractures are commonly treated with precontoured anterior plating. Some surgeons use mini-fragment plate fixation and position these plates on the anterior clavicle. Recent studies demonstrated the advantages of anterior clavicle plating, including a possible biomechanical advantage with cantilever bending forces and less subsequent implant removal. The insertion and positioning of anteriorly based clavicle plates requires the release of a portion of the anterior deltoid origin from the lateral clavicle. The purpose of this study is to evaluate the anatomy of the deltoid in relation to the clavicle and to determine the percentage of the deltoid origin released to place modern anterior precontoured plates.

METHODS

Six right and 4 left cadaver shoulders were dissected, each from separate cadaveric specimens (6 male and 4 female). All measurements were made with digital calipers. The length of the clavicle was measured from the acromioclavicular joint to the sternoclavicular joint. The length of deltoid origin on the lateral clavicle was measured from the acromioclavicular joint to the most medial attachment of the deltoid on the clavicle. Percentage of clavicle with deltoid origin was subsequently calculated.

RESULTS

The average length of the cadaveric clavicles was 164.4 mm with a range from 134.3 to 178.1 mm. The average amount of deltoid origin on the clavicle was 58.7 mm with a range from 43.4 to 69 mm. On average 35.5% of the clavicle had deltoid origin, with a range from 30.2% to 38.8%.

CONCLUSION

On average, 35.5% of the clavicular osseous anatomy contains deltoid origin. This should be taken into consideration when performing anterior plating for clavicle fractures. With a significant portion of deltoid origin elevated, surgeons may consider altering postoperative protocols until some interval healing has occurred to this anterior head of the deltoid.

Musculoskeletal modeling-based definition of load cases and worst-case fracture orientation for the design of clavicle fixation plates

Mechanical performance of clavicle fracture fixation plates is often evaluated using finite element (FE) analysis. Typically, these studies use simplified loading conditions and assume a transversal fracture orientation. However, the loading conditions and fracture orientation influence how the fracture site and thus fixation plate is loaded. In this study, a musculoskeletal model that included the clavicle muscles and scapulohumeral rhythm was defined based on previously published models. The standard OpenSim workflow (inverse kinematics, inverse dynamics, static optimization, and joint reaction analysis) was used to calculate muscle and joint contact forces based on 3D marker data collected in three subjects during seven activities of daily living (ADL). These loading conditions were then applied to a 3D clavicle model with three different fracture orientations and the mean resulting moments on both fragments were calculated to assess fracture stability. Magnitude of glenohumeral contact forces showed good agreement with instrumented shoulder prosthesis data, whereas simulated muscle activations were comparable to experimental EMG data. An oblique fracture orienting from superomedial to inferolateral was the least self-stabilizing. The loading to which the clavicle is exposed during ADL tasks is more complex than the simplified loading conditions typically used as boundary conditions in FE analyses of clavicle fracture fixation plates. Additionally, transversal fractures did not represent the least self-stabilizing fracture orientation, and thus calculated stresses in the plate could be underestimated. Therefore, more complex loading conditions and evaluation of a midshaft fracture running from superomedial to inferolateral is more relevant in FE analyses of midshaft clavicle fracture fixation plates.

Thin patient-specific clavicle fracture fixation plates can mechanically outperform commercial plates: An in silico approach

Current fixation plates used to operatively stabilize clavicular fractures are suboptimal, leading to reoperation rates up to 53%. Plate irritation, which can be caused by a poor geometric fit and plate thickness, has been found to be an important factor for reoperation. Moreover, muscle attachment sites (MAS) have to be detached occasionally. To improve current surgical clavicle fracture treatment with plate osteosynthesis, a change in plate design is required. The goal of this study was to design a patient-specific clavicle fracture fixation plate that includes geometrical optimization and stiffness determination. Its biomechanical performance has been compared with a commercial plate by examining the geometric fit, anatomical outline, stresses and interfragmentary motion using a finite element analysis with physiological loading and boundary conditions. Evaluation showed a better geometrical fit of the patient-specific plate as well as an improved fracture reduction. Displacements between fracture fragments were lower in case of the patient-specific plate, both when a fracture gap and no fracture gap were present. Results indicate a superior mechanical performance in terms of all investigated outcomes of the patient-specific plate compared to the commercial plate, while better aligning with the patient-specific geometry and without the need for MAS release. Due to the patient-specific geometry and reduced thickness, these fixation plates are expected to decrease the operation time, as intraoperative contouring will become irrelevant, and to decrease reoperation rates as implant irritation will be minimized.

Results of pre-contoured titanium anterior plating of midshaft clavicle fractures

BACKGROUND

Plating midshaft clavicle fractures anteriorly is gaining popularity because of low complication rates. Improvements in plate fixation constructs for midshaft clavicle fractures have unclear clinical significance. The purpose of this study was to present the early clinical and radiographic outcomes of pre-contoured titanium anterior plates for the treatment of midshaft clavicle fractures.

METHODS

Skeletally mature patients who underwent plate fixation of a midshaft clavicular fracture from 2008 to 2015 using pre-contoured titanium anterior plates were included in this retrospective investigation. The primary outcome measures were union rate and hardware removal rate. The secondary outcome measures included reoperation for all causes and mechanical implant failure.

RESULTS

A total of 26 patients were included. Complete healing occurred in 96% of patients without further surgical intervention, and all patients achieved union. Medical complications occurred in 2 patients (7.7%), consisting of cellulitis (n = 1) and chronic pain (n = 1). In 1 patient (3.8%), delayed union occurred and the use of a bone stimulator was required postoperatively to achieve union. Finally, 2 patients (7.7%) had symptomatic implants that required removal.

CONCLUSIONS

In the acute fracture setting, the anterior plating system used in this study led to a high rate of union with decreased rates of implant irritation. Only 7.7% of patients required hardware removal for symptomatic hardware, as opposed to the estimated 20%-60% reported in the literature in patients with symptomatic superior clavicle plates.

Current concepts in the treatment of midshaft clavicle fractures in adults

Midshaft clavicle fractures are the most common fracture of the clavicle accounting for 80% of all clavicle fractures. Traditionally, midshaft clavicle fractures are treated with conservative treatment even when prominent displacement is observed; however, recent studies revealed that nonunion or malunion rate may be higher with conservative treatment. Moreover, recent studies have shown better functional results and patient satisfaction with surgical treatment. This review article provides a review of clavicle anatomy, describes the current clavicle fracture classification system, and outlines various treatment options including current surgical options for clavicle fracture in adults.

Can Syndesmosis Screws Displace the Distal Fibula?

Background. There has been historical debate as to whether the distal tibiofibular syndesmosis can be overtightened during operative fixation. We used finite-element analysis to determine if overtightening of syndesmotic screws can cause widening of the lateral gutter clear space in the ankle joint. Methods. A 3D finite-element model was constructed and analyzed using geometries from a computed tomography scan of a cadaveric lower leg. Starting 2 cm from the plafond, screw fixation was simulated at 5-mm increments to a distance of 5 cm from the plafond. The fibula was compressed 2 mm toward the tibia at each interval, and the change in distance between the lateral talus and distal fibula was measured. Results. Medial deflection of the fibula resulted in widening of the lateral clear space, which was proportional to the amount of deflection. The effect increased as screws were placed closer to the plafond, with 1.5 mm of widening at 2 cm (0.76 mm/mm) versus 0.7 mm at 5 cm (0.34 mm/mm). Conclusion. Our finite-element model demonstrated that overtightening of the distal tibiofibular syndesmosis with medial fibular displacement can cause widening of the lateral clear space. Clinical relevance. The results suggest that screws placed farther from the plafond widen the lateral clear space to a lesser degree, which may be advantageous during surgical fixation to prevent clear space widening and increased tibiotalar contact forces.Levels of Evidence: Level I.

Mechanical Evaluation of 2.7- Versus 3.5-mm Plating Constructs for Midshaft Clavicle Fractures

OBJECTIVES

This study compares the mechanical performance of 2.7- and 3.5-mm plating constructs for the treatment of midshaft clavicle fractures.

METHODS

Twenty-four synthetic clavicles were randomly divided into four treatment groups-Synthes 2.7-mm cold-worked calcaneal reconstruction plate with 6 (CRP6) or 8 bicortical screws (CRP8); Synthes 3.5-mm LCP reconstruction plate (RP; and Synthes 3.5-mm LCP precontoured superior-anterior clavicle plate (PCRP). All clavicles were plated, a wedge-shaped inferior cortical defect was created, and testing was performed using a cantilever bending model to determine bending stiffness and yield point for each construct.

RESULTS

Bending stiffness for the 3.5-mm PCRP construct was markedly higher when compared with the other three constructs, whereas the 3.5-mm RP construct was markedly stiffer than both of the 2.7-mm CR constructs. The yield point for the 3.5-mm PCRP construct was greater than the other three constructs; however, the yield point for the 2.7-mm CRP with six screws and with eight screws was higher than the 3.5-mm RP construct. The amount of displacement required to reach the yield point was highest for the 2.7-mm CRP with six screws. and this was markedly higher than the values for the other three constructs.

DISCUSSION

The 3.5-mm plates demonstrated increased bending stiffness compared with the 2.7-mm plates. Despite the lower resistance to bending forces, the cold-worked 2.7-mm plate exhibited a markedly higher yield point and required markedly more superior to inferior displacement to initiate plastic deformation when compared with the 3.5-mm LCP RP.

LEVEL OF EVIDENCE

Level IV.

The Use of a Vibro-Acoustic Based Method to Determine the Composite Material Properties of a Replicate Clavicle Bone Model

Replicate bones are widely used as an alternative for cadaveric bones for in vitro testing. These composite bone models are more easily available and show low inter-specimen variability compared to cadaveric bone models. The combination of in vitro testing with in silico models can provide further insights in the evaluation of the mechanical behavior of orthopedic implants. An accurate numerical representation of the experimental model is important to draw meaningful conclusions from the numerical predictions. This study aims to determine the elastic material constants of a commonly used composite clavicle model by combining acoustic experimental and numerical modal analysis. The difference between the experimental and finite element (FE) predicted natural frequencies was minimized by updating the elastic material constants of the transversely isotropic cortical bone analogue that are provided by the manufacturer. The longitudinal Young's modulus was reduced from 16.00 GPa to 12.88 GPa and the shear modulus was increased from 3.30 GPa to 4.53 GPa. These updated material properties resulted in an average natural frequency difference of 0.49% and a maximum difference of 1.73% between the FE predictions and the experimental results. The presented updated model aims to improve future research that focuses on mechanical simulations with clavicle composite bone models.

Biomechanical analysis of four augmented fixations of plate osteosynthesis for comminuted mid-shaft clavicle fracture: A finite element approach

Sufficient stabilization of comminuted mid-shaft clavicle fractures via plate fixation is difficult to achieve. Various augmentations, including interfragmentary screws and cerclage wiring, have been adopted to reinforce fixation stability. The present study aimed to assess the biomechanical stability of augmented plate fixations using the finite element method. First, a clavicle fracture model was created from CT data. Fixation was then induced using a locking compressive plate (LCP) with the following four augmentations: i) Double inner cerclage wirings (DICW), ii) double outer cerclage wirings (DOCW), iii) a single interfragmentary screw (SIS) and iv) double interfragmentary screws (DIS). Compressive and bending forces of 100 N were subsequently applied at the acromial region of the clavicle. The stress distribution, displacement and fracture micro-motions of the model were assessed and compared. The DOCW resulted in the highest stress exerted on the LCP, followed by SIS, DICW and DIS. For the clavicle fracture, DICW, DOCW and SIS resulted in high stress levels. However, DIS fixation alone resulted in levels of stress that were below the yield strength of cortical bone. Displacement analysis revealed that DOCW fixation resulted in the greatest degree of displacement and fracture micro-motions, followed by SIS, DICW and DIS. The results indicated that SIS, DIS and DOCW may be used as augmentations of LCP fixation for comminuted mid-shaft clavicle fractures. However, DIS was the recommended augmentation due to it exerting the lowest stress and the highest stability compared with the other fixations. The DICW may be used to aid fracture reduction and plate placement in surgery but should be avoided for permanent fixation.

TREATMENT OF MIDSHAFT CLAVICLE FRACTURE WITH SUPERIOR PLATE PLACEMENT

Objective:

To evaluate the late clinical and radiological results of patients had locking plate anatomically compatible from superior surface and muscle cover on plate due to clavicle mid-region.

Materials and Methods:

Forty patients were included retrospectively. Patients had a routine right shoulder anterior posterior graph after examination. The results were assessed by returning to the patient's daily activities, Constant score, the Disability of the Arm, and Shoulder and Hand scoring, followed by radiological and clinical examination.

Results:

Fourteen (35%) patients were female and 26 (65%) were male. The mean age was 36.2 years. Twenty-six patients had right clavicle fracture and 14 patients had left. Twenty-three fractures were type 2B1 and 17 fractures were type 2B2. Mean follow-up time was 36.4 months. Radiologic union was at a mean of 9.1 ± 1.3 weeks. All patients had excellent results. The mean Constant score was 97.2 ± 1.8, the mean Disability of the Arm, and Shoulder and Hand score was 3.8 ± 2.4.

Conclusion:

It is possible to obtain complete union with high patient satisfaction by avoiding the complications and difficulties of the conservative treatment with the use of the anatomically compatible locking plates in superior fixation and our surgical dissection. Level of Evidence III, Retrospective Case controlled study.

Finite element analysis of spiral plate and Herbert screw fixation for treatment of midshaft clavicle fractures

Both spiral plate and Herbert screw fixations have been clinically adopted for treating midshaft displaced clavicle fractures. However, the biomechanical properties of the 2 implant fixations have not yet been thoroughly evaluated. Here we report the results of a finite element analysis of the biomechanical properties of midshaft clavicle fractures treated with Herbert screw and spiral plate fixation. Hebert screw fixation showed stress distribution similar to intact clavicle under all loading conditions, but provided less stability than did spiral plate fixation. Postoperatively, excessive shoulder activities and weight-bearing should be avoided. Spiral plate fixation provides greater stability, but is associated with stress shielding. These results demonstrate that Herbert screw fixation is suitable for the treatment of simple displaced clavicluar fractures, but excessive shoulder activity and weight-bearing should be avoided after the operation. Therefore, spiral plate fixation may be preferred for patients requiring an early return to activity.

A single centre experience of pre-contoured clavicle plates by an anterior approach

AIM

In recent years there has been increasing evidence that comminuted and shortened clavicle fractures should be treated surgically. The aim of this study was to assess the outcome of patients who had their clavicle fracture fixed using a pre-contoured, clavicle specific plate from an anterior approach.

METHOD

A retrospective analysis was carried out of all patients treated with pre-contoured clavicle plates from an anterior approach between May 2014 and June 2016.Medical records were analysed, and a phone survey was carried out to assess patient function and note any complications.

RESULTS

Thirty-five eligible patients were identified. Post-operative complications included: 3 patients experienced altered sensation of the anterior chest wall, 2 suture granulomas, 1 incidence of prominent metalwork. In addition, 2 patients suffered peri-implant fractures due to secondary trauma after union. Patients who had Open Reduction and Internal Fixation (ORIF) for acute fractures had a mean qDASH of 8.93 and those who had a ORIF and bone grafting for non-union had an mean qDASH of 34.38.

CONCLUSION

Although there are 6 complications listed for 33 procedures, these would be considered minor. Patients appear to do better if treated for an acute fracture. Anterior approach for clavicle ORIF using an anatomically shaped pre-contoured plate appears to be a safe and effective procedure.

Biomechanical Analysis of Superior and Anterior Precontoured Plate Fixation Techniques for Neer Type II-A Clavicle Fractures

OBJECTIVE

There are limited biomechanical data supporting the use of anterior or superior-lateral precontoured clavicle plates for the treatment of displaced Neer type II-A clavicle fractures. The objectives of this study were as follows: (a) compare noncontoured versus precontoured superior plating; (b) compare use of locking versus nonlocking screws in the lateral fragment for superior precontoured plates; and (c) compare superior versus anterior precontoured plates with locking lateral fragment screws.

METHODS

The following constructs were tested on a synthetic clavicle model simulating a Neer type II-A fracture: (a) superior precontoured plate with locking (SUP-L, n = 6); (b) superior precontoured plate with nonlocking (SUP-NL, n = 8); (c) anterior precontoured plate with locking (ANT-L, n = 7); and (d) superior noncontoured locking compression plate (SUP-LCP, n = 6). Constructs were subjected to cyclical cantilever loads. Construct stiffness and survival (cycles to failure) were documented. Mann-Whitney U tests were performed for group-wise statistical comparison (α = 0.05) of data.

RESULTS

The SUP-L construct was significantly stiffer than both SUP-LCP and ANT-L constructs (P < 0.02). The SUP-NL construct was stiffer than the SUP-L (P = 0.03) construct. Both SUP-L and ANT-L precontoured constructs survived longer than the noncontoured SUP-LCP construct (P < 0.022). The SUP-L construct survived longer than the SUP-NL (P = 0.013) and the ANT-L (P = 0.008) constructs.

CONCLUSIONS

Superior precontoured plates yielded biomechanically superior constructs compared with anterior precontoured and superior noncontoured plates. Using locking screws in the lateral fragment over nonlocking screws may improve overall superior precontoured plate construct survivability. However, our results were limited to a synthetic biomechanical model and require further investigation to establish a clinical correlation.

Immediate Weight-bearing as Tolerated has Improved Outcomes Compared to Non–weight-bearing after Surgical Stabilisation of Midshaft Clavicle Fractures in Polytrauma Patients

Background

Clavicle fractures are common injuries in the polytrauma population and frequently limit early mobilisation. This study evaluates the effect of immediate crutch weight-bearing (WB) in polytrauma patients after surgical stabilisation of a displaced midshaft clavicle fracture.

Methods

A retrospective review identified 26 polytrauma patients with operatively managed displaced midshaft clavicle fractures and a non–weight-bearing (NWB) lower extremity injury. Patients were allowed immediate WB after surgery or NWB. The primary outcome was total hospital length of stay. Statistical analysis was done using Mann–Whitney U test.

Results

The WB group had decreased total hospital length of stay (10.4 vs. 17.0 days, p = 0.012) and improved physical therapy score (3.9 vs. 2.9, p = 0.054) and postoperative length of stay (6.8 vs. 12.7 days, p = 0.006) compared with the NWB group.

Conclusions

Our data suggest that an immediate WB as tolerated protocol for polytrauma patients after surgical fixation of displaced clavicle fractures may decrease the overall length of stay.

Management of Midshaft Clavicle Fractures in Adults

Fractures of the clavicle are common injuries that occur across all age groups but are most frequently seen in the young, active patient population. Among the different types of clavicle fractures, those occurring in the middle third of the clavicular shaft are the most common. Historically, most of these fractures were treated by closed means even when notable displacement was present. Recently, there has been a renewed interest in assessing the best treatment option for these patients. Although nonsurgical treatment is a reliable method for treating many of these fractures, more recent data suggest that fractures with notable displacement (>2 cm of shortening or >100% displacement) and/or comminution have better short-term outcomes and lower rates of nonunion with surgical management. Current surgical options include superior plating, anterior-inferior plating, dual plating, and intramedullary nail fixation.

Risk of fracture of the acromion depends on size and orientation of acromial bone tunnels when performing acromioclavicular reconstruction

PURPOSE

Current techniques for anatomic repair of the dislocated acromioclavicular (AC) joint aim on reconstruction of the AC ligaments and utilize tunnels drilled through the acromion . This improves the stability of the reconstruction but might also increase the risk of fractures at the acromion. The purpose of this study was to evaluate the fracture risk for the acromion after transacromial tunnel placement for anatomic AC joint stabilization procedure. It was hypothesized that the risk of fracture of the acromion is correlated to size and orientation of bone tunnels commonly used for anatomic AC joint reconstruction.

METHODS

A finite element analysis was used to simulate multiple bone tunnels and incoming force vectors (lateral vs. superior). Different tunnels were analysed, horizontal meaning an anterior-posterior orientation versus a vertical inferior-superior orientation through the acromion. Two tunnel diameters were simulated (2.4 vs. 4.5 mm). Furthermore, the tunnel length and distance between tunnels were altered. Forty-five cadaveric specimens (median age: 64 years, range 33-71 years) were utilized for data acquisition. Out of these, 30 specimens were used to evaluate basic tunnel orientations and drill diameters using a MTS 858 servohydraulic test system.

RESULTS

With regard to the tunnel orientation and drill hole size, the loads to failure were limited. The acromion is at higher fracture risk, with a superior to inferior directed incoming force. Position, size and direction of bone tunnels influenced the loads to failure. Horizontal tunnels with a higher diameter (4.5 mm) had the most impact on load to failure reduction. A long horizontal tunnel with a diameter of 4.5 mm reduced the load to failure with medial direction of force to 25% of the native acromion. The identical tunnel with a diameter of 2.4 mm reduced the load to failure to 61%. Both 2.4-mm horizontal tunnels with a medium and short length did not reduce the load to failure.

CONCLUSION

Tunnels placed at the acromion did not result in an increased risk of fracture. However, descriptive data showed a tendency for an increased fracture risk if tunnels are placed at the acromion, especially in horizontal direction with diameters of 4.5 mm. In addition, the pattern of fracture was dependent on the orientation of the bone tunnels and the size. However, the results indicate a "safe zone" for the placement of bone tunnels within the anterior half of the acromion, which does not affect the loads to failure at the acromion. Therefore, current techniques for anatomic AC joint reconstruction which utilize fixation of grafts or sutures at the acromion are safe within current ranges of tunnel placement and sizes.

Anterior-Inferior Plating Results in Fewer Secondary Interventions Compared to Superior Plating for Acute Displaced Midshaft Clavicle Fractures

OBJECTIVES

To determine whether a difference in plate position for fixation of acute, displaced, midshaft clavicle fractures would affect the rate of secondary intervention.

DESIGN

Retrospective Comparative Study.

SETTING

Two academic Level 1 Regional Trauma Centers.

PATIENTS

Five hundred ten patients treated surgically for an acutely displaced midshaft clavicle fracture between 2000 and 2013 were identified and reviewed retrospectively at a minimum of 24 months follow-up (F/U). Fractures were divided into 2 cohorts, according to plate position: Anterior-Inferior (AI) or Superior (S). Exclusion criteria included age <16 years, incomplete data records, and loss to F/U. Group analysis included demographics (age, sex, body mass index), fracture characteristics (mechanism of injury, open or closed), hand dominance, ipsilateral injuries, time between injury to surgery, time to radiographic union, length of F/U, and frequency of secondary procedures.

INTERVENTION

Patients were treated either with AI or S clavicle plating at the treating surgeon's discretion.

MAIN OUTCOME MEASURES

Rate and reason for secondary intervention.

STATISTICAL ANALYSIS

Fisher exact test, t test. and odds ratio were used for statistical analysis.

RESULTS

Final analysis included 252 fractures/251 patients. One hundred eighteen (47%) were in group AI; 134 (53%) were in group S. No differences in demographics, fracture characteristics, time to surgery, time to union, or length of F/U existed between groups. Seven patients/7 fractures (5.9%) in Group AI underwent a secondary surgery whereas 30 patients/30 fractures (22.3%) in group S required a secondary surgery. An additional intervention secondary to superior plate placement was highly statistically significant (P < 0.001). Furthermore, because 80% of these subsequent interventions were a result of plate irritation with patient discomfort, the odds ratio for a second procedure was 5 times greater in those fractures treated with a superior plate.

CONCLUSIONS

This comparative analysis indicates that AI plating of midshaft clavicle fractures seems to lessen clinical irritation and results in significantly fewer secondary interventions. Considering patient satisfaction and a reduced financial burden to the health care system, we recommend routine AI plate application when open reduction internal fixation of the clavicle is indicated.

LEVEL OF EVIDENCE

Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.

Superior versus anteroinferior plating of displaced midshaft clavicular fracture in patients older than 60 years

Objective

To compare superior versus anteroinferior plating for displaced midshaft clavicular fracture in elderly patients.

Methods

We retrospectively compared the functional result, parameters, and perioperative course of displaced midshaft clavicular fracture in 42 patients >60 years treated with a 3.5-mm reconstruction plate placed superiorly versus anteroinferiorly.

Results

Groups were similar with regard to age, sex, bone mineral density, cause of injury, and fracture pattern. The superiorly-plated group had a significantly longer operation time and greater blood loss, complications and implant prominence. Constant scores were significantly higher for the anteroinferiorly-plated group than the superiorly-plated group at 3 months postoperatively; however, there was no difference between groups at final follow-up.

Conclusion

While both anteroinferior and superior plate placement are safe and effective for displaced midclavicular fractures in patients >60 years, the anteroinferior approach involves less operation time, blood loss, complications and implant prominence, and enables faster return to normal activities.

Symptomatic Implant Removal Following Dual Mini-Fragment Plating for Clavicular Shaft Fractures

OBJECTIVES

To determine the proportion of patients requiring secondary surgery for symptomatic implant removal after open reduction, internal fixation using dual mini-fragment plating technique for clavicular shaft fractures.

DESIGN

Retrospective observational study.

SETTING

Single university Level 1 trauma center.

PATIENTS

Eighty-one patients treated with open reduction, internal fixation using dual mini-fragment plating technique for clavicular shaft fractures (OTA/AO 15-B1, B2, and B3) with minimum 12-month follow-up (median 477 days; range 371-1549 days).

INTERVENTION

Open reduction, internal fixation using dual mini-fragment plating technique for clavicular shaft fractures.

MAIN OUTCOME MEASUREMENTS

Incidence of secondary surgery, QuickDASH (Disabilities of the Arm, Shoulder, and Hand) scores.

RESULTS

Six of 81 patients (7.4%) underwent secondary surgery for implant removal for any reason. Of these, 3 (3.7%) underwent symptomatic implant (soft-tissue irritation) removal, 2 (2.5%) required implant removal in the setting of infection, and 1 patient (1.2%) required revision open reduction internal fixation for early implant failure. The mean QuickDASH score in this series was 8.44 (±6.94, range 0-77.27). The associated implant cost of the typical construct utilized in this series was $1511.38. The mean surgical time was 97 minutes (range 71-143 minutes).

CONCLUSIONS

The utilization of a dual mini-fragment plating technique in the treatment of clavicular shaft fractures results in a low rates of secondary surgery for symptomatic implant removal (3.7%) and similar QuickDASH scores when compared with historical controls treated with 3.5-mm plates placed on the superior clavicle. Potential disadvantages in using this technique include a higher surgical implant cost and length of surgery.

LEVEL OF EVIDENCE

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

Biomechanical Comparison of Superior Versus Anterior Plate Position for Fixation of Distal Clavicular Fractures: A New Model

OBJECTIVES

Although most clavicular fractures are amenable to nonoperative management, metadiaphyseal fractures are considerably more complex, with rates of suboptimal healing as high as 75% when treated nonoperatively. The poor results are ascribed to the deforming forces on the distal clavicle from the surrounding muscles and the weight of the arm. It recently has been noted that some operative fixations of these fractures are also failing when a standard superiorly placed plate is used. We hypothesized that anterior plating, when compared with superior plating, improves the strength and durability of the construct by redirecting the axis of the major deforming force across rather than in line with the screws of the construct.

METHODS

Six pairs of fresh-frozen human cadaveric clavicles with the scapula attached by the coracoclavicular ligaments were osteotomized just medial to the ligaments and plated with a standard 3.5-mm limited-contact dynamic compression plate. Specimens were potted and mounted on a materials testing system machine, preserving the anatomic relationship of the clavicle and scapula. They were then loaded through the coracoclavicular ligaments to mimic the weight of the arm pulling inferiorly. Each specimen was loaded with 375 N at 1 Hz for 2000 cycles. Sequential loading was then applied at 25-N intervals until failure. Statistical analysis was performed using a Wilcoxon signed-rank test.

RESULTS

The superiorly plated specimens failed after fewer cycles and with lower force than the anteriorly plated specimens. The median number of cycles to failure was 2082 for anterior plated specimens and 50 for superiorly plated (P = 0.028). The median load to failure was 587.5 N in the anterior group and 375 N in the superior group (P = 0.035). The median stiffness was 46.13 N/mm for anterior and 40.45 N/mm for superior (P = 0.375) plates.

CONCLUSIONS

Anteriorly plated distal third clavicular fractures have superior strength and durability compared with fractures plated superiorly when using a physician-contoured, 3.5-mm, limited-contact, dynamic compression plate in this cadaver model.

Midshaft Clavicle Fractures: A Critical Review

The clavicle is the most commonly broken bone in the human body, accounting for up to 5% to 10% of all fractures seen in hospital emergency admissions. Fractures of the middle third, or midshaft, are the most common, accounting for up to 80% of all clavicle fractures. Traditional treatment of midshaft clavicle fractures is usually nonoperative management, using a sling or figure-of-eight bandage. The majority of adults treated nonoperatively for midshaft clavicle fractures will heal completely. However, newer studies have shown that malunion, pain, and deformity rates may be higher than previously reported with traditional management. Recent evidence demonstrates that operative treatment of midshaft clavicle fractures can result in better functional results and patient satisfaction than nonoperative treatment in patients meeting certain criteria. This article provides a review of relevant anatomy, classification systems, and injury mechanisms for midshaft clavicle fractures, as well as a comparison of various treatment options. [Orthopedics.2016; 39(5):e814-e821.].

Finite element analysis of locking plate and two types of intramedullary nails for treating mid-shaft clavicle fractures

BACKGROUND

Both plate and intramedullary nail fixations, including straight and anatomic nails, have been clinically adopted for the treatment of displaced mid-shaft clavicle fractures. However, the biomechanical performances of these fixations and implants have not been well evaluated. This study aims to compare the construct stability, stress distribution and fracture micro-motion of three fixations based on finite element (FE) method.

METHODS

The FE model of clavicle was reconstructed from CT images of a male volunteer. A mid-shaft fracture gap was created in the intact clavicle. Three fixation styles were simulated including locking plate (LP), anatomic intramedullary nail (CRx), and straight intramedullary nail (RCP). Two loading scenarios (axial compression and inferior bending) were applied at the distal end of the clavicle to simulate arm abduction, while the sternal end was fixed.

RESULTS

Under both conditions, the LP was the stiffest, followed by the CRx, and the RCP was the weakest. LP also displayed a more evenly stress distribution for both implant and bone. RCP had a higher stress compared with CRx in both conditions. Moreover, all implants sustained higher stress level under the loading condition of bending than compression.

CONCLUSIONS

The plate fixation significantly stabilizes the fracture gap, reduces the implant stress, and serves as the recommended fixation for the mid-shaft clavicle fracture. The CRx is an alternative device to treat clavicle shaft fracture, but the shoulder excessive activities should be avoided after operation.

Intramedullary Fixation of Clavicle Fractures: Anatomy, Indications, Advantages, and Disadvantages

Historically, management of displaced midshaft clavicle fractures has consisted of nonsurgical treatment. However, recent literature has supported surgical repair of displaced and shortened clavicle fractures. Several options exist for surgical fixation, including plate and intramedullary (IM) fixation. IM fixation has the potential advantages of a smaller incision and decreased dissection and soft-tissue exposure. For the last two decades, the use of Rockwood and Hagie pins represented the most popular form of IM fixation, but concerns exist regarding stability and complications. The use of alternative IM implants, such as Kirschner wires, titanium elastic nails, and cannulated screws, also has been described in limited case series. However, concerns persist regarding the complications associated with the use of these implants, including implant failure, migration, skin complications, and construct stability. Second-generation IM implants have been developed to reduce the limitations of earlier IM devices. Although anatomic and clinical studies have supported IM fixation of midshaft clavicle fractures, further research is necessary to determine the optimal fixation method.

Minimally invasive plate osteosynthesis for midshaft clavicular fractures using superior anatomic plating

BACKGROUND

The minimally invasive plate osteosynthesis procedure has been widely applied for long-bone fixations; however, this technique is not commonly used for clavicular midshaft fractures. In this study, we introduced this technique for midshaft clavicular fractures using superior anatomic locking plates and evaluated its clinical and radiographic outcomes.

MATERIALS AND METHODS

From June 2013 to July 2014, 15 patients with acute midshaft clavicular fractures were treated with the minimally invasive plate osteosynthesis technique using a 3.5-mm clavicular superior anatomic locking plate. Anteroposterior plain X-ray images of the clavicle were taken at 4-week intervals until union was observed. The last clinical follow-up assessments were performed postoperatively at a mean of 16.54 months (range, 10-23 months). In addition, for clinical evaluations, the Constant score and the Disability of the Arm, Shoulder and Hand score were assessed.

RESULTS

The average operative time was 60.2 ± 20.1 minutes (range, 40-80 minutes), with blood loss of 25 ± 5 mL (range, 20-30 mL) during the operation. The mean union time for the patients was 10.1 ± 1.4 weeks (range, 8-12 weeks), and no delayed union or nonunion was observed. There were no major complications, including infections, plate breakages, or neurovascular injuries. No skin irritation was observed, and only 2 patients felt local incision numbness. All patients obtained satisfactory shoulder functions. The mean Constant score was 99 ± 1.8 (range, 95-100), and the mean Disability of the Arm, Shoulder and Hand score was 3.8 ± 2.9 (range, 0-10) at the last control visit.

CONCLUSION

The minimally invasive plate osteosynthesis procedure that was introduced in this study for midshaft clavicular fractures with superior anatomic locking plate is a reproducible procedure and an alternative to conventional operative methods.

Dual mini-fragment plating for midshaft clavicle fractures: a clinical and biomechanical investigation

BACKGROUND

We sought to evaluate clinical and biomechanical outcomes of dual mini-fragment plate fixation for clavicle fractures. We hypothesized that this technique would produce an anatomical reduction with good clinical outcomes, be well tolerated by patients, and demonstrate equivalent biomechanics to single plating.

METHODS

Dual mini-fragment plating was performed for 17 isolated, displaced midshaft clavicle fractures. Functional outcomes and complications were retrospectively reviewed. A sawbones model compared dual plating biomechanics to a (1) superior 3.5-mm locking reconstruction plate, or (2) antero-inferior 3.5-mm locking reconstruction plate.

RESULTS

On biomechanical testing, with anterior loading, dual plating was significantly more rigid than single locked anterior-plating (p = 0.02) but less rigid than single locked superior-plating (p = 0.001). With superior loading, dual plating trended toward higher rigidity versus single locked superior-plating (p = 0.07) but was less rigid than single locked anterior-plating (p = 0.03). No statistically significant differences in axial loading (p = 0.27) or torsion (p = 0.23) were detected. Average patient follow-up was 16.1 months (12-38). Anatomic reduction was achieved and maintained through final healing (average 14.7 weeks). No patient underwent hardware removal. Average 1-year DASH score was 4.0 (completed in 88 %).

CONCLUSIONS

Displaced midshaft clavicle fractures can be effectively managed with dual mini-fragment plating. This technique results in high union rates and excellent clinical outcomes. Compared to single plating, dual plating is biomechanically equivalent in axial loading and torsion, yet offers better multi-planar bending stiffness despite the use of smaller plates. This technique may decrease the need for secondary surgery due to implant prominence and may aid in fracture reduction by buttressing butterfly fragments in two planes.

Clinical comparison of two different plating methods in minimally invasive plate osteosynthesis for clavicular midshaft fractures: A randomized controlled trial

AIM

The aim of this study was to compare the clinical and radiographic outcomes between two different plating methods (superior vs. anteroinferior) in minimally invasive plate osteosynthesis (MIPO) for acute displaced clavicular shaft fractures.

MATERIALS AND METHODS

A prospective, randomized controlled trial was performed in a single centre. Nineteen patients were treated with superior plating and 18 with anteroinferior plating using the MIPO technique. A 3.5-mm locking reconstruction plate was bent preoperatively and applied to either the anteroinferior or superior aspect of the clavicle through two separate incisions. The operating time, time to union, the proportional length difference, complications, and functional outcome of the shoulder joint were evaluated using the Constant score and the University of California Los Angeles (UCLA) score.

RESULTS

There was no statistically significant difference in the Constant score and UCLA score. The mean time to union was 16.8 weeks for superior plating and 17.1 weeks for anteroinferior plating (p=0.866). The average operation time was 77.2min in superior plating and 79.4min in anteroinferior plating (p=0.491). One patient in the superior plating group showed plate failure. Despite no significant difference, one patient had nonunion in the superior plating group (p>0.999).

CONCLUSIONS

From a clinical perspective, although MIPO with anteroinferior plating provides better outcomes especially in complications without statistically significant difference, both plating methods provided satisfactory clinical and radiographic outcomes.

LEVEL OF EVIDENCE

Level I, a single-centre, prospective, randomized controlled trial.

Operative versus nonoperative treatment for displaced midshaft clavicle fractures: a meta-analysis based on current evidence

Literature searches of the Cochrane Library, PubMed, EMBASE, Web of Science, LILACS, China National Knowledge Infrastructure, and Wanfang Data databases were performed from 1966 to September 2014. Only randomized and quasi-randomized controlled clinical trials comparing operative and nonoperative treatments for displaced midshaft clavicle fractures were included. Data collection and extraction, quality assessment, and data analyses were performed according to the Cochrane standards. Thirteen studies were considered in the meta-analysis. Constant scores and the Disabilities of the Arm, Shoulder and Hand scores were improved in the operative fixation group at a follow up of one year or more. The nonunion and symptomatic malunion rates were significantly lower in the operative group. Additionally, the nonoperative group had a higher likelihood of neurological symptoms compared with the operative group. A significantly higher risk of complications was found in patients treated conservatively than in those who underwent operative fixation. However, when patients with nonunion and symptomatic malunion were excluded from the analysis, no significant differences in the complication rate were found. We concluded that based on the current clinical reports, operative treatment is superior to nonoperative treatment in the management of displaced midshaft clavicle fractures. However, we do not support the routine use of primary operative fixation for all displaced midshaft clavicle fractures in adults.

Titanium Elastic Nail (TEN) versus Reconstruction Plate Repair of Midshaft Clavicular Fractures: A Finite Element Study

BACKGROUND

The biomechanical characteristics of midshaft clavicular fractures treated with titanium elastic nail (TEN) is unclear. This study aimed to present a biomechanical finite element analysis of biomechanical characteristics involved in TEN fixation and reconstruction plate fixation for midshaft clavicular fractures.

METHODS

Finite element models of the intact clavicle and of midshaft clavicular fractures fixed with TEN and with a reconstruction plate were built. The distal clavicle displacement, peak stress, and stress distribution on the 3 finite element models were calculated under the axial compression and cantilever bending.

RESULTS

In both loading configurations, TEN generated the highest displacement of the distal clavicle, followed by the intact clavicle and the reconstruction plate. TEN showed higher peak bone and implant stresses, and is more likely to fail in both loading configurations compared with the reconstruction plate. TEN led to a stress distribution similar to that of the intact clavicle in both loading configurations, whereas the stress distribution with the reconstruction plate was nonphysiological in cantilever bending.

CONCLUSIONS

TEN is generally preferable for treating simple displaced fractures of the midshaft clavicle, because it showed a stress distribution similar to the intact clavicle. However, TEN provides less stability, and excessive exercise of and weight bearing on the ipsilateral shoulder should be avoided in the early postoperative period. Fixation with a reconstruction plate was more stable but showed obvious stress shielding. Therefore, for patients with a demand for early return to activity, reconstruction plate fixation may be preferred.

Strength analysis of clavicle fracture fixation devices and fixation techniques using finite element analysis with musculoskeletal force input

In the cases, when clavicle fractures are treated with a fixation plate, opinions are divided about the best position of the plate, type of plate and type of screw units. Results from biomechanical studies of clavicle fixation devices are contradictory, probably partly because of simplified and varying load cases used in different studies. The anatomy of the shoulder region is complex, which makes it difficult and expensive to perform realistic experimental tests; hence, reliable simulation is an important complement to experimental tests. In this study, a method for finite element simulations of stresses in the clavicle plate and bone is used, in which muscle and ligament force data are imported from a multibody musculoskeletal model. The stress distribution in two different commercial plates, superior and anterior plating position and fixation including using a lag screw in the fracture gap or not, was compared. Looking at the clavicle fixation from a mechanical point of view, the results indicate that it is a major benefit to use a lag screw to fixate the fracture. The anterior plating position resulted in lower stresses in the plate, and the anatomically shaped plate is more stress resistant and stable than a regular reconstruction plate.

Does plate type influence the clinical outcomes and implant removal in midclavicular fractures fixed with 2.7-mm anteroinferior plates? A retrospective cohort study

BACKGROUND

The purpose of this study was to evaluate surgical healing rates, implant failure, implant removal, and the need for surgical revision with regards to plate type in midshaft clavicle fractures fixed with 2.7-mm anteroinferior plates utilizing modern plating techniques.

METHODS

This retrospective exploratory cohort review took place at a level I teaching trauma center and a single large private practice office. A total of 155 skeletally mature individuals with 156 midshaft clavicle fractures between March 2002 and March 2012 were included in the final results. Fractures were identified by mechanism of injury and classified based on OTA/AO criteria. All fractures were fixed with 2.7-mm anteroinferior plates. Primary outcome measurements included implant failure, malunion, nonunion, and implant removal. Secondary outcome measurements included pain with the visual analog scale and range of motion. Statistically significant testing was set at 0.05, and testing was performed using chi-square, Fisher's exact, Mann-Whitney U, and Kruskall-Wallis.

RESULTS

Implant failure occurred more often in reconstruction plates as compared to dynamic compression plates (p = 0.029). Malunions and nonunions occurred more often in fractures fixed with reconstruction plates as compared to dynamic compression plates, but it was not statistically significant. Implant removal attributed to irritation or implant prominence was observed in 14 patients. Statistically significant levels of pain were seen in patients requiring implant removal (p = 0.001) but were not associated with the plate type.

CONCLUSIONS

Anteroinferior clavicular fracture fixation with 2.7-mm dynamic compression plates results in excellent healing rates with low removal rates in accordance with the published literature. Given higher rates of failure, 2.7-mm reconstruction plates should be discouraged in comparison to stiffer and more reliable 2.7-mm dynamic compression plates.

Hot topics in biomechanically directed fracture fixation

The evolution of locking plates and modern nail constructs provides the orthopaedic trauma surgeon with a myriad of options with regard to implant selection for common fractures. There is a significant amount of biomechanical literature comparing modern constructs with those conventionally used. A basic understanding of this literature is required to make informed decisions with regard to implant selection in the management of these injuries. This article reviews the most recent biomechanical literature regarding implant selection and application for a variety of commonly treated injuries, including fractures of the clavicle, proximal humerus, distal humerus, intertrochanteric hip region, distal femur, and bicondylar tibial plateau.

Superior versus anteroinferior plating of clavicle fractures

Plate fixation of displaced clavicle fractures has proven to be reliable and reproducible, leading to high union rates and a low rate of associated complications. However, the decision of whether to place the plate superiorly or anteroinferiorly on the clavicle has remained controversial. The authors performed a retrospective review on a consecutive series of patients who underwent plate fixation for a displaced midshaft clavicle fracture at a Level I urban trauma center. A review of surgical records identified 138 patients with a displaced midshaft clavicle fracture requiring operative stabilization. A total of 105 patients who met the inclusion criteria were included in the analysis. Both superior and anteroinferior techniques resulted in a similar time to radiographic union (12.6±4.8 vs 11.3±5.2 weeks, respectively) and identical union rates (95%). At final follow-up, patient-reported implant prominence was nearly double in patients with a retained superior plate (54% vs 29%, respectively; P=.04). No significant difference existed in mean visual analog scale score at a mean of 2.77 years postoperatively, although a significant difference existed in the Oxford Shoulder Score questionnaire, with a mean score of 41.4 in the superior group and 44.4 in the anteroinferior group (P=.008). Implant removal occurred more frequently after superior plating but was not significant. Both superior and anteroinferior clavicle plating are safe treatment methods for displaced clavicle fractures. Superior plating leads to an increased rate of patient-reported implant prominence and may prompt more requests for implant removal.

Results of anterior-inferior 2.7-mm dynamic compression plate fixation of midshaft clavicular fractures

OBJECTIVES

To evaluate the outcome of operatively treated unstable displaced diaphyseal clavicle fractures with anterior-inferior 2.7-mm dynamic compression plate (DCP) fixation.

DESIGN

Retrospective review of clavicle fractures.

SETTING

Level-1 trauma teaching center.

PATIENTS/PARTICIPANTS

One hundred twenty-nine clavicle fractures.

INTERVENTION

An anterior-inferior approach to clavicle fractures was used with the application of a 2.7-mm DCPs.

MAIN OUTCOME MEASUREMENT

Radiographic assessment of healing and complication rates.

RESULTS

One hundred twenty-five fractures healed (97%). Postoperative complications included 1 superficial wound problem, 3 deep wound problems, 5 nonunions, and 4 prominent implants requiring removal in 3.

CONCLUSIONS

Anterior-inferior placement of 2.7-mm DCPs seems safe and is associated with minimal complications.

LEVEL OF EVIDENCE

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

Biomechanical effects of the nail entry zone and anterior cortical bone loss on the proximal tibia

OBJECTIVES

The aims of this study were as follows: to determine if the presence of the nail entry zone alters the biomechanics of the proximal tibia after intramedullary (IM) nailing using a computational model; to determine if nail removal restores normal biomechanics to the proximal tibia; and to determine if these effects are magnified with anterior cortical bone loss.

METHODS

Three-dimensional finite element (FE) tibial models were developed and used for this study: an intact tibia, a nailed tibia, and a tibia with the nail removed. One matched pair of fresh-frozen cadaver tibias was obtained to construct and validate the FE model. The tibias underwent computed tomography scanning, and geometric models were obtained from computed tomography data through volumetric reconstruction. The left tibia was implanted with an unlocked IM nail. The experimental validation of the models was performed by comparing experimental and FE data. Anterior cortical bone of the proximal tibia was removed down to the tibial tubercle on the models to simulate a worst-case scenario of its removal during an IM nailing procedure. Three load cases were considered for each FE tibial model: standing, walking, and single-limb kneeling.

RESULTS

The principal strain values of the proximal tibia with the nail entry zone were increased in comparison to the intact tibia in all 3 loading scenarios (+350%-550%). These effects were greatly magnified with anterior cortical bone loss near the nail entry zone (6-fold increase). The presence of the nail increased the principal strain values in the proximal tibia both with an intact and a disrupted anterior cortex in all loading scenarios, and these values remain elevated even with removal of the nail. The values predicted by the FE model were in good agreement with the experimentally measured strains (R = 0.92).

CONCLUSION

The nail entry zone in the proximal tibia greatly increases the principle strain values when standing, walking, and kneeling. The presence of the nail results in the highest strain values, but they do not return to normal when the nail is removed. These effects are significantly amplified with removal of the anterior tibial cortex near the nail entry zone.