Locking plates have increased torsional stiffness compared to standard plates in a segmental defect model of clavicle fracture

Biomechanical and clinical evaluation of minimal invasive plate osteosynthesis for two-part clavicle shaft fractures

BACKGROUND

Many surgical treatment methods exist for clavicle shaft fractures. A locking compression plate (LCP) fixation with three screws per fracture side is commonly used. For certain fractures a stabilization with 2 screws per side is potentially suitable, offering the advantage of reduced soft tissue approach, while avoiding the disadvantages of minimally-invasive nailing at the same time. This hypothesis was evaluated biomechanically and clinically.

METHODS

Four treatment procedures were investigated biomechanically using composite human clavicle specimens. A load-to-failure test was performed using a three-point cantilever test. In group 1, a simple shaft fracture was simulated and stabilized with 2 screws per fracture side (5-hole LCP). In the second group 3 screws per side (7-hole LCP) were used. In group 3, a non-reduced fracture zone was simulated and treated with 3 screws per side (7-hole LCP). In group 4, an anatomically reduced fracture zone was simulated and treated with 3 screws per side (7-hole LCP). Furthermore 27 patients treated with a short plate and 2 screws per side (similar to group 1) were assessed after a minimum follow-up of 12 months (Constant and DASH Score).

RESULTS

The maximum load-to-failure of group 1 was 367N. We observed the highest load-to-failure in group 2 with 497N and the lowest in group 3 with 90N. In group 4 a maximum load-to-failure of 298N could be evaluated. There was no significant difference in load-to-failure between the treatment of a simple clavicle fracture using 5- or 7-hole LCP (p = 0.121). However, we found a significant difference of load-to-failure between the simple and anatomically reduced fracture using a 7-hole plate (p = 0.014). The mean constant score of the surgically treated patients was 95 and the DASH score 3.0. Fracture consolidation was observed in 96.3%.

CONCLUSIONS

For certain non-fragmented and well interlocking 2-part fractures, a plate osteosynthesis fixed with only 2 screws per fracture side might offer sufficient biomechanical stability, better soft tissue preservation and comparable fusion rates compared to the operative treatment with 3 screws per side. However, the maximum load-to-failure of the 7-hole LCP was higher than of the 5-hole LCP, but this difference was not statistically significant.

TRIAL REGISTRATION

Approval from the ethics committee of the Technical University of Dresden was retrospectively obtained (EK 588122019).

Different internal fixation methods for Hoffa-like fractures of the tibial plateau: a finite element analysis

Due to the low incidence of posteromedial tibial plateau fractures and limited clinical data available, the optimal treatment for this type of fracture remains to be established. This type of fracture, also known as Hoffa-like fracture of the tibial plateau, shares a similar mechanism of injury with the Hoffa fracture of the femoral condyle. In the field of orthopedics, finite element analysis is considered a valuable method to guide clinical decision-making. In this study, four methods used for internal fixation of Hoffa-like fractures of the tibial plateau were compared using computer simulation and applying a finite element method (FEM). The methods compared were lateral L-plate fixation alone (Model A); lateral L-plate combined with posterior anti-slip plate (reconstruction plate/T-plate) fixation (Model B); lateral L-plate combined with posterior hollow nail fixation of the fracture block (Model C); and lateral L-plate combined with anterior hollow nail fixation of the fracture (Model D). The maximum displacement of the model and the maximum stress of the internal fixation material were analyzed by applying an axial load of 2,500 N. The results showed that, in the normal bone model, the maximum displacement of the fracture in Model A was 0.60032 mm, with improved stability through the addition of posterior lateral plate fixation in Model B and reduction of the displacement to 0.38882 mm. The maximum displacement in Model C and Model D was comparable, amounting to 0.42345 mm and 0.42273 mm, respectively. Maximum stress was 1235.6 MPa for Model A, 84.724 MPa for Model B, 99.805 MPa for Model C, and 103.19 MPa for Model D. In the internal fixation analysis of the osteoporotic fracture model, we observed patterns similar to the results of the normal bone model. The results indicated that Model B yielded the overall best results in the treatment of Hoffa-like fractures of the tibial plateau. The orthopedic surgeon may wish to implement these insights into the perioperative algorithm, thereby refining and optimizing clinical patient care. In addition, our findings pave the way for future research efforts.

Biomechanical analysis of plating techniques for unstable lateral clavicle fractures with coracoclavicular ligament disruption (Neer type IIB)

BACKGROUND

Neer type IIB lateral clavicle fractures are inherently unstable fractures with associated disruption of the coracoclavicular (CC) ligaments. Because of the high rate of nonunion and malunion, surgical fixation is recommended; however, no consensus has been reached regarding the optimal fixation method. A new plating technique using a superior lateral locking plate with anteroposterior (AP) locking screws, resulting in orthogonal fixation in the lateral fragment, has been designed to enhance stability and reduce implant failure. The purpose of this study was to biomechanically compare 3 different clavicle plating constructs within a fresh frozen human cadaveric shoulder model.

METHODS

Twenty-four fresh frozen cadaveric shoulders were randomized into 3 groups (n = 8 specimens): group 1, lateral locking plate only (Medartis Aptus Superior Lateral Plate); group 2, lateral locking plate with CC stabilization (No. 2 FiberWire); and group 3, lateral locking plate with 2 AP locking screws stabilizing the lateral fragment. All specimens were subject to cyclic loading of 70 N for 500 cycles. Data were analyzed for gap formation after cyclic loading, construct stiffness, and ultimate load to failure, defined by a marked decrease in the load displacement curve.

RESULTS

After 500 cycles, there was no statistically significant difference between the 3 groups in gap formation (P = .179). No specimen (0/24) failed during cyclic loading. Ultimate load to failure was significantly higher in group 3 compared to group 1 (286 N vs. 167 N; P = .022), but not to group 2 (286 N vs. 246 N; P = .604). There were no statistically significant differences in stiffness (group 1: 504 N/mm; group 2: 564 N/mm; group 3: 512 N/mm; P = .712). Peri-implant fracture was the primary mode of failure for all 3 groups, with group 3 demonstrating the lowest rate of peri-implant fractures (group 1: 6/8; group 2: 7/8; group 3: 4/8; P = .243).

CONCLUSION

Biomechanical evaluation of the clavicle plating techniques showed effective fixation across all specimens at 500 cycles. The lateral locking plate with orthogonal AP locking screw fixation in the lateral fragment demonstrated the greatest ultimate failure load, followed by the lateral locking plate with CC stabilization. This new plating technique showed compatible stiffness and gap formation when compared to conventional lateral locking plates as well as plates with CC fixation. The use of orthogonal screw fixation in the distal fragment may negate against the need for CC stabilization in these types of fractures, thus minimizing surgical dissection around the coracoid and potential complications.

Intraoperative Nice knots assistance for reduction in displaced comminuted clavicle fractures

PURPOSE

The Nice knots have been widely used in orthopedic surgeries to fix torn soft tissue and fracture in recent years. The study aims to investigate the clinical efficacy and prognosis of intraoperative and postoperative Nice Knots-assisted reduction in the treatment of displaced comminuted clavicle fracture.

METHODS

From Jan 2014 to Dec 2019, 75 patients diagnosed with unilateral closed displaced comminuted clavicle fracture were treated with open reduction and internal fixation (ORIF) in this study. Nice knot group (the NK group) included 38 patients and the other 37 patients were in the traditional group (the TK group). The time of operation and the amount of bleeding during operation were recorded. Post-operative clinical outcomes and radiographic results were recorded and compared between these two groups. The Visual Analogue Scale (VAS), Neer score, Rating Scale of the American Shoulder and Elbow Surgeons, Constant-Murley score and complications such as infection, nonunion, implant loosening, fragment displacement and hardware pain were observed in the two groups.

RESULTS

In the comparison between the two groups, there was no significant difference in age, sex, the cause of displaced clavicle fracture, and other basic information between the two groups. The operation time, intraoperative fluoroscopy time, and intraoperative blood loss were significantly reduced in the NK group (P < 0.01). There were 2 cases of plate fracture in the TK group. The follow-up results showed that there was no significant difference in VAS, Neer score, ASES, and Constant-Murley scores between the two groups.

CONCLUSION

The use of Nice knot, in comminuted and displaced clavicle fractures can reduce intraoperative blood loss, shorten operation time, facilitate intraoperative reduction, and achieve satisfactory postoperative clinical results. This study demonstrates that Nice knot is a simple, safe, practical and effective auxiliary reduction method.

Comparison of radiological and clinical outcomes, complications, and implant removals in anatomically pre-contoured clavicle plates versus reconstruction plates - a propensity score matched retrospective cohort study of 106 patients

Background

Plate fixation is frequently used to treat displaced midshaft clavicular fractures, however the ideal plate choice remains subject to discussion; reconstruction locking compression plates (RLCPs) are cheaper and can be easily contoured, whereas anatomically pre-contoured locking compression plates (ALCPs) are thought to provide better stability and therefore lower rates of mechanical failure.

To compare the incidence of mechanical failures, functional and radiological outcomes in patients with midshaft clavicular fractures treated with ALCPs versus RLCPs.

Methods

A propensity score matched retrospective cohort study was conducted across two centers. One hundred and six consecutively recruited patients with displaced midshaft clavicular fractures, who were treated with plate fixation and had a minimum follow-up of 6 months, were matched on gender, age, fracture grading, energy of injury, and fracture location. The resulting groups included 53 ALCP-treated fractures and 53 matched controls treated with RLCPs.

Results

During a mean follow-up of 20.5 months, there were no implant deformities in the ALCP group whereas the RLCP group had 6 patients (11.3%, p = 0.012) with implant deformities (5 occurrences of plate bending with fracture union, and 1 plate breakage with nonunion). Despite the higher rate of plate deformities in the RLCP group, there were no statistically significant differences in number of patients recovering full shoulder range of motion (ALCP 90.6%, RLCP 88.7%, p = 0.751), incidence of rest pain (ALCP 13.2%, RLCP 9.4%, p = 0.542), or implant removals (ALCP 49.1%, RLCP 56.6%, p = 0.439).

Conclusion

ALCPs may be superior to RLCPs in terms of implant stability but appear to produce similar clinical results.

Surgical fixation of midshaft clavicle fractures: A systematic review of biomechanical studies

PURPOSE

Surgical treatment of displaced midshaft clavicle fractures requires a decision between plate fixation and intramedullary (IM) fixation. Numerous studies report on the biomechanical properties of various repair constructs. The goal of this systematic review was to provide an overview of studies describing the biomechanical properties of the most commonly used surgical fixations of midshaft clavicle fractures. Additionally, we aimed to translate these biomechanical results into clinically relevant conclusions.

METHODS

A computer-aided search of the EMBASE and PudMed/MEDLINE databases was conducted. Studies included for review compared biomechanical properties of plate fixation with IM fixation and superiorly positioned plates with anteroinferiorly positioned plates for midshaft clavicle fractures.

RESULTS

Fifteen studies were eligible for inclusion. Plate fixation seemed to form a more robust construct than IM fixation in terms of stiffness and failure loading. The remaining clavicle was stronger after removal of the IM device than after removal of the plate. Superior plating of transverse fractures generally seemed to provide greater stiffness and strength during bending loads than anteroinferior plating did. The absence of cortical alignment in wedge and comminuted fractures directly influenced the fixation stability for both IM fixation and plate fixation, regardless of location.

CONCLUSION

Each type of fracture fixation has biomechanical advantages and disadvantages. However, exact thresholds of stiffness for inducing healing and failure strength to withstand refractures are unknown. The clinical relevance of the biomechanical studies may be arguable. Since none of the studies investigate the effect of tissue adaptation over time they should be interpreted with caution.

Ex vivo cyclic mechanical behaviour of 2.4 mm locking plates compared with 2.4 mm limited contact plates in a cadaveric diaphyseal gap model

Objectives: To compare the mechanical properties of locking compression plate (LCP) and limited contact dynamic compression plate (LC-DCP) constructs in an experimental model of comminuted fracture of the canine femur during eccentric cyclic loading.

Methods: A 20 mm mid-diaphyseal gap was created in eighteen canine femora. A 10-hole, 2.4 mm stainless steel plate (LCP or LC-DCP) was applied with three bicortical screws in each bone fragment. Eccentric cyclic loadings were applied at 10 Hertz for 610,000 cycles. Quasistatic loading / unloading cycles were applied at 0 and 10,000 cycles, and then every 50,000 cycles. Structural stiffness was calculated as the slope of the linear portion of the load-displacement curves during quasistatic loading / unloading cycles.

Results: No bone failure or screw loosening occurred. Two of the nine LCP constructs failed by plate breakage during fatigue testing, whereas no gross failure occurred with the LC-DCP constructs. The mean first stiffness of the LCP constructs over the course of testing was 24.0% lower than that of constructs stabilized by LC-DCP. Construct stiffness increased in some specimens during testing, presumably due to changes in boneplate contact. The first stiffness of LC-DCP constructs decreased by 19.4% and that of locked constructs by 34.3% during the cycling period. A biphasic stiffness profile was observed: the second stiffness was significantly greater than the first stiffness in both groups, which allowed progressive stabilization at elevated load levels.

Clinical significance: Because LCP are not compressed to the bone, they may have a longer working length across a fracture, and thus be less stiff. However, this may cause them to be more susceptible to fatigue failure if healing is delayed.

Biomechanical Comparison of Locking Compression Plate and Limited Contact Dynamic Compression Plate Combined with an Intramedullary Rod in a Canine Femoral Fracture-Gap Model

OBJECTIVE

To compare the biomechanical properties of locking compression plate (LCP) and a limited contact dynamic compression plate combined with an intramedullary rod (LC-DCP-R) in a cadaveric, canine, femoral fracture-gap model.

STUDY DESIGN

In vitro biomechanical study; nonrandomized, complete block (dog).

SAMPLE POPULATION

Paired cadaveric canine femora (n = 10 dogs).

METHODS

Paired femurs with a mid-diaphyseal 20 mm gap were stabilized with either LCP or LC-DCP-R. Nondestructive testing up to 60% of body weight (BW) was followed by a continuous destructive test. Comparative structural properties, 3-dimensional (3D) interfragmentary motion, and plate linear strain were evaluated. Paired comparisons were made between LCP and LC-DCP-R.

RESULTS

Stiffness after nondestructive testing was significantly lower for LCP with a mean (95% confidence interval [CI]) of 61 N/mm (46-76) versus 89 N/mm (67-110) for LC-DCP-R (P = .0072). Ultimate load to failure was significantly lower for LCP with a median (interquartile range [IQR]) of 270 N (247-286) versus 371.5 (353-385) for LC-DCP-R (P = .002). Axial motion at 60% BW was significantly higher for LCP with a median (IQR) of 1.01 mm (0.71-1.26) versus 0.36 mm (0.20-0.49) for LC-DCP-R (P = .002). Shear motion was significantly higher for LCP with a median (IQR) of 1.18 (0.78-1.58) versus 0.72 mm (0.45-1.00) for LC-DCP-R (P = .018). Strain was significantly higher for mid-LCP surface with a mean (95%CI) at 60% BW of 979 μdef (579-1378) versus 583 μdef (365-801) at mid-LC-DCP-R surface (P = .0153). The elastic limit strain of the plates was not different and was reached at a mean (95%CI) load of 241 N (190-292) for LCP versus 290 N (245-336) for LC-DCP-R (P = .12).

CONCLUSION

The LC-DCP-R showed higher stiffness and resistance to failure, lower interfragmentary motion, and lower plate strain and stress compared to LCP.

Optimal internal fixation of anatomically shaped synthetic bone grafts for massive segmental defects of long bones

BACKGROUND

Large segmental bone defects following tumor resection, high-energy civilian trauma, and military blast injuries present significant clinical challenges. Tissue engineering strategies using scaffolds are being considered as a treatment, but there is little research into optimal fixation of such scaffolds.

METHODS

Twelve fresh-frozen paired cadaveric legs were utilized to simulate a critical sized intercalary defect in the tibia. Poly-ε-caprolactone and hydroxyapatite composite scaffolds 5 cm in length with a geometry representative of the mid-diaphysis of an adult human tibia were fabricated, inserted into a tibial mid-diaphyseal intercalary defect, and fixed with a 14-hole large fragment plate. Optimal screw fixation comparing non-locking and locking screws was tested in axial compression, bending, and torsion in a non-destructive manner. A cyclic torsional test to failure under torque control was then performed.

FINDINGS

Biomechanical testing showed no significant difference for bending or axial stiffness with non-locking vs. locking fixation. Torsional stiffness was significantly higher (P=0.002) with the scaffold present for both non-locking and locking compared to the scaffold absent. In testing to failure, angular rotation was greater for the non-locking compared to locking constructs at each torque level up to 40 N-m (P<0.05). The locking constructs survived a significantly higher number of loading cycles before reaching clinical failure at 30 degrees of angular rotation (P<0.02).

INTERPRETATION

The presence of the scaffold increased the torsional stiffness of the construct. Locking fixation resulted in a stronger construct with increased cycles to failure compared to non-locking fixation.

Operative Treatment of an Atypical Segmental Bipolar Fracture of the Clavicle

Introduction:

Clavicle fractures are very common, accounting for approximately 4% of all adult fractures. Segmental bipolar fractures involving the lateral and the medial ends of the clavicle are extremely rare, with only isolated cases reported in the literature. The injury mechanism is often unclear and the management of these fractures remains controversial.

Case presentation:

Here is to report a case of a segmental bipolar fracture of the clavicle with a lateral fracture and a displaced medial fracture without dislocation of the sternoclavicular joint following a low energy fall to the outstretched hand, and discuss its management.

Conclusions:

Stability of the clavicle is crucial for shoulder function and care should be taken not to miss or underestimate segmental bipolar fractures even with a low energy mechanism. Authors believe that operative treatment should be taken into consideration for displaced fractures.

Stress and stability of plate-screw fixation and screw fixation in the treatment of Schatzker type IV medial tibial plateau fracture: a comparative finite element study

Purpose

The purpose of this study is to compare the stress and stability of plate-screw fixation and screw fixation in the treatment of Schatzker type IV medial tibial plateau fracture.

Methods

A three-dimensional (3D) finite element model of the medial tibial plateau fracture (Schatzker type IV fracture) was created. An axial force of 2500 N with a distribution of 60 % to the medial compartment was applied to simulate the axial compressive load on an adult knee during single-limb stance. The equivalent von Mises stress, displacement of the model relative to the distal tibia, and displacement of the implants were used as the output measures.

Results

The mean stress value of the plate-screw fixation system was 18.78 MPa, which was significantly (P < 0.001) smaller than that of the screw fixation system. The maximal value of displacement (sum) in the plate-screw fixation system was 2.46 mm, which was lower than that in the screw fixation system (3.91 mm). The peak stress value of the triangular fragment in the plate-screw fixation system model was 42.04 MPa, which was higher than that in the screw fixation model (24.18 MPa). But the mean stress of the triangular fractured fragment in the screw fixation model was significantly higher in terms of equivalent von Mises stress (EVMS), x-axis, and z-axis (P < 0.001).

Conclusions

This study demonstrated that the load transmission mechanism between plate-screw fixation system and screw fixation system was different and the stability provided by the plate-screw fixation system was superior to the screw fixation system.

Plate Versus Intramedullary Fixation Care of Displaced Midshaft Clavicular Fractures: A Meta-Analysis of Prospective Randomized Controlled Trials

In recent decades, there has been a growing trend to the operative treatment of displaced midshaft clavicular fractures. Open reduction and internal plate fixation, and intramedullary nailing fixation are 2 of the widely used techniques for operative treatment, but the optimal fixation method for these types of fractures remains a topic of debate. The objective of this study was to determine the effectiveness of plate fixation versus intramedullary nailing fixation for displaced midshaft clavicle fractures by comparing their clinical results.Literature searches of the Pubmed, EMBASE, and Web of Science were performed from 1966 to April, 2015. Only randomized controlled clinical trials comparing plate and intramedullary nailing treatment for displaced midshaft clavicle fractures were included. Literature was screened, data were extracted, and methodological quality of the eligible trials was assessed by 2 independent reviewers accordingly.Seven randomized controlled trials involving 421 patients were included. Compared to intramedullary nailing fixation, plate fixation had a relatively longer mean surgical time and a trend towards a faster functional improvement during the first 6 months after surgery; apart from this, the pooled results revealed no significant differences in functional scores after 6 months postoperatively, complication rate and patients' satisfaction between plate fixation and intramedullary fixation.Our results demonstrated that these 2 methods were comparable and safe in the treatment of displaced midshaft clavicle fractures. We advocate both techniques for the treatment of displaced midshaft clavicle fractures, and the superior surgical technique was those that the surgeon was originally trained to perform.

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.

Unicortical versus bicortical locked plate fixation in midshaft clavicle fractures

Higher rates of poor outcomes in displaced midshaft clavicle fractures treated nonoperatively have recently been reported. Along with expanding indications for operative fixation and increasing application of locked plate constructs, it is unknown whether complications related to bicortical penetration of the clavicle can be avoided using unicortical fixation. The purpose of this study is to compare the biomechanical properties of unicortical and bicortical fixation in precontoured vs manually contoured locking clavicle plates. Forty-eight Sawbone composite human clavicle specimens (item #3408; Pacific Research Laboratories, Vashon, Washington) with a midshaft clavicle osteotomy were reduced and plated in 8 specimens each using a bicortical and unicortical fixation for each of 3 locked plate constructs (3.5-mm LCP Reconstruction Plate; 3.5-mm LCP Superior Clavicle Plate; 3.5-mm LCP Superior Anterior Clavicle Plate; Synthes, Inc, West Chester, Pennsylvania). Specimens were tested for stiffness in axial torsion and cantilever bending and then loaded to failure in 3-point bending. Data were analyzed using 2-way analysis of variance and Tukey's test (P<.05). No significant differences were found between unicortical and bicortical fixation in failure load, cantilever bending, and cross body stiffness. Bicortical fixation was significantly stiffer than unicortical fixation in torsion only for the same plates. Significant differences also existed between plates in torsion. Unicortical locked plate fixation may be a reasonable option in the treatment of displaced midshaft clavicle fracture fixation to avoid complications associated with posteroinferior hardware penetration following clavicle fracture fixation based on the biomechanical performance of these constructs. However, it remains unclear whether these differences will be clinically significant.

Comparison of dynamic and locked compression plates for treating midshaft clavicle fractures

The purpose of this study was to compare the parameters of perioperative course and cost-effectiveness for patients with midshaft clavicle fractures treated by dynamic compression plates or locked compression plates.This retrospective, case-controlled study involved 54 patients with midshaft clavicle fractures who received dynamic compression plates (n=21) or locked compression plates (n=33) between January 2002 and December 2008. Indications for surgery included displacement or shortening >2 cm, comminuted fractures, and skin tenting. Patients with previous malunion, nonunion, multiple injuries of the shoulder girdle, or open fractures were excluded. Preoperative demographics showed no statistically significant differences between the 2 groups. Eighteen patients with dynamic compression plates and 28 patients with locked compression plates with postoperative follow-up >1 year were included for comparison. Statistical analyses for operative time, blood loss, complication rate, hospital stay, and union rate demonstrated no statistically significant difference between the 2 groups. The only statistically significant difference was a higher rate of plate removal requests in the dynamic compression plate group. Considering medical expenditure, locked compression plates cost 6 times more than dynamic compression plates in the authors' institution (US $600 vs $100, respectively).Other than more plate removal requests in the dynamic compression plate group and greater expense in the locked compression plate group, dynamic compression plates and locked compression plates achieved satisfactory operative outcomes in treating midshaft clavicle fractures, with no statistically significant difference between perioperative course and eventual fracture union observed between the 2 groups.