Biomechanical analysis of the efficacy of locking plates during cyclic loading in metacarpal fractures.
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ABSTRACT:
SUBMITTER: Doht S
PROVIDER: S-EPMC3976824 | biostudies-other | 2014
REPOSITORIES: biostudies-other
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Project description:PURPOSE: Fixed-angle devices have been a major advancement in orthopedic fracture care and have become an attractive option for fixation of distal radius fractures. Several volar locking plates exist, but there is insufficient literature comparing the strengths of these plates. This study compares the biomechanical strength of two popular volar locking plate systems (Synthes LCP and Hand Innovations DVR-A) along with a nonlocking volar T-plate (Synthes). METHODS: Twenty-three formalin-fixed cadaveric forearms were divided into three groups with similar ages and bone densities. An unstable extra-articular fracture was created using a standardized osteotomy. Each group was fixed with one of the three plates. Each specimen was loaded in axial compression for 2000 cycles at a force of 400 N. Each specimen that completed cyclic testing was loaded to failure. Stiffness, yield point, and ultimate strength were recorded for each construct. RESULTS: Each fixed-angle construct completed all 2000 cycles. The nonlocking plates failed at an average of 560 cycles. The mean stiffness of the DVR-A, LCP, and the volar T-plates were 277.00, 343.17, and 175.67 N/mm, respectively. There was a statistically significant difference between both fixed-angle plates and the nonlocking plate (p < 0.05). The difference between each fixed-angle construct did not reach significance. Yield point and ultimate strength could only be determined for the two fixed-angle devices. There was no statistically significant difference between the constructs for both yield point (DVR-A = 855.56 N, LCP = 894.15 N) and ultimate strength (DVR-A = 1,021.97 N, LCP = 1,114.87 N). CONCLUSIONS: Given our data, fixed-angle constructs withstand cyclical loading representing normal physiologic forces encountered during post-operative rehabilitation. There was no significant biomechanical difference between the two fixed-angle constructs. Our results support that volar fixed-angle locking plates are an effective treatment for unstable extra-articular distal radius fractures, allowing early postoperative rehabilitation to safely be initiated.
| S-EPMC2528971 | biostudies-other
Project description:BackgroundThe treatment of Dubberley type B capitellar fractures, which are frequently complicated, is widely debated. This study aimed to investigate the prognostic factors and clinical outcomes of Dubberley type B capitellar fractures treated with Herbert screws combined with posterior buttress plates.MethodsSeven men and nine women (aged 30-68 years) with Dubberley type B capitellar fractures were operated on with Herbert screws combined with posterior buttress plates. The patients were classified into Dubberley types IB (seven), IIB (four), and IIIB (five). Complications and bone union were observed, and functional outcomes were evaluated by the Mayo Elbow Performance Index (MEPI).ResultsAll patients were followed up for a mean period of 23.5 months (12-30 months). All fractures healed in 8-14 weeks (mean, 10.5 weeks). No cases of non-union, elbow instability, or avascular necrosis occurred. Degenerative arthritis occurred in 7 (44%) and heterotopic ossification in 11 (69%) patients. The median MEPI score was 92.5 (interquartile range, 85-100) points, with 11 reporting excellent, 3 good, and 2 fair outcomes. The MEPI scores of type IIIB fractures were significantly lower than those of types IB and IIB fractures, while the MEPI scores of type IB and IIB fractures did not differ significantly.ConclusionsDubberley type IIIB capitellar fractures with multiple articular fragments have a poorer prognosis than type IB and IIB fractures. However, Herbert screw fixation combined with posterior metacarpal locking plates is feasible, providing satisfactory recovery of elbow joint function.
| S-EPMC10694941 | biostudies-literature
Project description:Joint-preserving surgical treatment of complex unstable proximal humerus fractures remains challenging, with high failure rates even following state-of-the-art locked plating. Enhancement of implants could help improve outcomes. By overcoming limitations of conventional biomechanical testing, finite element (FE) analysis enables design optimization but requires stringent validation. This study aimed to computationally enhance the design of an existing locking plate to provide superior fixation stability and evaluate the benefit experimentally in a matched-pair fashion. Further aims were the evaluation of instrumentation accuracy and its potential influence on the specimen-specific predictive ability of FE. Screw trajectories of an existing commercial plate were adjusted to reduce the predicted cyclic cut-out failure risk and define the enhanced (EH) implant design based on results of a previous parametric FE study using 19 left proximal humerus models (Set A). Superiority of EH versus the original (OG) design was tested using nine pairs of human proximal humeri (N = 18, Set B). Specimen-specific CT-based virtual preoperative planning defined osteotomies replicating a complex 3-part fracture and fixation with a locking plate using six screws. Bone specimens were prepared, osteotomized and instrumented according to the preoperative plan via a standardized procedure utilizing 3D-printed guides. Cut-out failure of OG and EH implant designs was compared in paired groups with both FE analysis and cyclic biomechanical testing. The computationally enhanced implant configuration achieved significantly more cycles to cut-out failure compared to the standard OG design (p < 0.01), confirming the significantly lower peri-implant bone strain predicted by FE for the EH versus OG groups (p < 0.001). The magnitude of instrumentation inaccuracies was small but had a significant effect on the predicted failure risk (p < 0.01). The sample-specific FE predictions strongly correlated with the experimental results (R2 = 0.70) when incorporating instrumentation inaccuracies. These findings demonstrate the power and validity of FE simulations in improving implant designs towards superior fixation stability of proximal humerus fractures. Computational optimization could be performed involving further implant features and help decrease failure rates. The results underline the importance of accurate surgical execution of implant fixations and the need for high consistency in validation studies.
| S-EPMC9260250 | biostudies-literature
Project description:Locked bridge plating relies on secondary bone healing, which requires interfragmentary motion for callus formation. This study evaluated healing of fractures stabilized with a locked plating construct and a far cortical locking construct, which is a modified locked plating approach that promotes interfragmentary motion. The study tested whether far cortical locking constructs can improve fracture-healing compared with standard locked plating constructs.In an established ovine tibial osteotomy model with a 3-mm gap size, twelve osteotomies were randomly stabilized with locked plating or far cortical locking constructs applied medially. The far cortical locking constructs were designed to provide 84% lower stiffness than the locked plating constructs and permitted nearly parallel gap motion. Fracture-healing was monitored on weekly radiographs. After the animals were killed at week 9, healed tibiae were analyzed by computed tomography, mechanical testing in torsion, and histological examination.Callus on weekly radiographs was greater in the far cortical locking constructs than in the locked plating constructs. At week 9, the far cortical locking group had a 36% greater callus volume (p = 0.03) and a 44% higher bone mineral content (p = 0.013) than the locked plating group. Callus in the locked plating specimens was asymmetric, having 49% less bone mineral content in the medial callus than in the lateral callus (p = 0.003). In far cortical locking specimens, medial and lateral callus had similar bone mineral content (p = 0.91). The far cortical locking specimens healed to be 54% stronger in torsion (p = 0.023) and sustained 156% greater energy to failure in torsion (p < 0.001) than locked plating specimens. Histologically, three of six locked plating specimens had deficient bridging across the medial cortex, while all remaining cortices had bridged.Inconsistent and asymmetric callus formation with locked plating constructs is likely due to their high stiffness and asymmetric gap closure. By providing flexible fixation and nearly parallel interfragmentary motion, far cortical locking constructs form more callus and heal to be stronger in torsion than locked plating constructs.
| S-EPMC2897208 | biostudies-literature
Project description:BackgroundThe exact benefit of locking plates over nonlocking plates in patients with lateral malleolus fractures remains unclear. The primary aim of this study was to compare the functional outcome of locking plates vs nonlocking plates in patients with a lateral malleolus fracture. The secondary aims were to compare the number of complications and hardware removals and to compare whether results differed for older patients and for patients treated with anatomical locking plates.MethodsThe PubMed/MEDLINE, Embase, Cochrane, and CINAHL databases were searched for studies comparing locking plates with nonlocking plates in patients with fixated lateral malleolus fractures. All included studies were assessed on their methodologic quality using the MINORS. Subgroup analyses were performed on older patients and patients treated with anatomical locking plates.ResultsA total of 11 studies were included. The meta-analysis showed that functional outcome did not differ between patients treated with locking plates and nonlocking plates (MD 2.38, 95% CI -2.71 to 7.46). No difference in both complication rate (OR 1.10, 95% CI 0.74-1.63) and the amount of hardware removals (OR 0.77, 95% CI 0.52-1.14) was found. Even after analyzing older patients and patients treated with anatomical locking plates, no benefit was shown.ConclusionThis meta-analysis demonstrates no clear benefit in selecting locking plates over nonlocking plates in the treatment of lateral malleolus fractures.Clinical relevanceLocking plates are increasingly being used in the treatment of lateral malleolus fractures. Biomechanical studies have shown an increased stability with use of locking vs nonlocking plates. This clinical review does not support a benefit of use of locking plates for these fractures.
| S-EPMC8841627 | biostudies-literature
Project description:BackgroundThe locking plate is a useful treatment for lateral clavicle fractures, however, there are limits to the fragment size that can be fixed. The current study aimed to measure the screw angles of three locking plates for lateral clavicle fractures. In addition, to assess the number of screws that can be inserted in different fragment sizes, to elucidate the size limits for locking plate fixation.MethodsThe following three locking plates were analyzed: the distal clavicle plate [Acumed, LLC, Oregon, the USA], the LCP clavicle plate lateral extension [Depuy Synthes, LLC, PA, the USA], and the HAI clavicle plate [HOMS Engineering, Inc., Nagano, Japan]. We measured the angles between the most medial and lateral locking screws in the coronal plane and between the most anterior and posterior locking screws in the sagittal plane. A computer simulation was used to position the plates as laterally as possible in ten normal three-dimensional clavicle models. Lateral fragment sizes of 10, 15, 20, 25, and 30 mm were simulated in the acromioclavicular joint, and the number of screws that could be inserted in the lateral fragment was assessed. Subsequently, the area covered by the locking screws on the inferior surface of the clavicle was measured.ResultsThe distal clavicle plate had relatively large screw angles (20° in the coronal plane and 32° in the sagittal plane). The LCP clavicle lateral extension had a large angle (38°) in the sagittal plane. However, the maximum angle of the HAI clavicle plate was 13° in either plane. The distal clavicle plate allowed most screws to be inserted in each size of bone fragment. For all locking plates, all screws could be inserted in 25 mm fragments. The screws of distal clavicle plate covered the largest area on the inferior surface of the clavicle.ConclusionsScrew angles and the numbers of screws that could be inserted in the lateral fragment differed among products. Other augmented fixation procedures should be considered for fractures with fragment sizes < 25 mm that cannot be fixed with a sufficient number of screws.
| S-EPMC8456609 | biostudies-literature
Project description:BackgroundDistal radius fractures are common, costly, and increasing in incidence. Percutaneous K-wire fixation and volar locking plates are two of the most commonly used surgical treatments for unstable dorsally displaced distal radius fractures. However, there is uncertainty regarding which of these treatments is superior.Questions/purposesWe performed a meta-analysis of randomized controlled trials to determine whether patients treated with volar locking plates (1) achieved better function (2) attained better wrist motion, (3) had better radiographic outcomes, and (4) had fewer complications develop than did patients treated with K-wires for dorsally displaced distal radius fractures.MethodsWe performed a comprehensive search of MEDLINE (inception to 2014, October Week 2), EMBASE (inception to 2014, Week 42), and the Cochrane Central Register of Controlled Trials to identify relevant randomized controlled trials; we supplemented these searches with manual searches. We included studies of extraarticular and intraarticular distal radius fractures. Adjunctive external fixation was acceptable as long as the intent was to use only K-wires where possible and external fixation was used in less than 25% of the procedures. We considered a difference in the DASH scores of 10 as the minimal clinically important difference. We performed quality assessment with the Cochrane Risk of Bias tool and evaluated the strength of recommendations using the Grades of Recommendation, Assessment, Development and Evaluation (GRADE) approach. Seven randomized trials with a total of 875 participants were included in the meta-analysis.ResultsPatients treated with volar locking plates had slightly better function than did patients treated with K-wires as measured by their DASH scores at 3 months (mean difference [MD], 7.5; 95% CI, 4.4-10.6; p < 0.001) and 12 months (MD, 3.8; 95% CI, 1.2-6.3; p = 0.004). Neither of these differences exceeded the a priori-determined threshold for clinical importance (10 points). There was a small early advantage in flexion and supination in the volar locking plate group (3.7° [95% CI, 0.3°-7.1°; p = 0.04] and 4.1° [95% CI, 0.6°-7.6°; p = 0.02] greater, respectively) at 3 months, but not at later followups (6 or 12 months). There were no differences in radiographic outcomes (volar tilt, radial inclination, and radial height) between the two interventions. Superficial wound infection was more common in patients treated with K-wires (8.2% versus 3.2%; RR = 2.6; p = 0.001), but otherwise no difference in complication rates was found.ConclusionsDespite the small number of studies and the limitations inherent in a meta-analysis, we found that volar locking plates show better DASH scores at 3- and 12-month followups compared with K-wires for displaced distal radius fractures in adults; however, these differences were small and unlikely to be clinically important. Further research is required to better delineate if there are specific radiographic, injury, or patient characteristics that may benefit from volar locking plates in the short term and whether there are any differences in long-term outcomes and complications.Level of evidenceLevel I, therapeutic study.
| S-EPMC4523532 | biostudies-literature
Project description:The lag screw technique has historically been a successful and accepted way to treat oblique metacarpal fractures. However, it does take additional time and involve multiple steps that can increase the risk of fracture propagation or comminution in the small hand bones of the hand. An alternate fixation technique uses bicortical interfragmentary screws. Other studies support the clinical effectiveness and ease of this technique. The purpose of this study is to biomechanically assess the strength of the bicortical interfragmentary screw versus that of the traditional lag screw. Using 48 cadaver metacarpals, oblique osteotomies were created and stabilized using one of four methods: 1.5 mm bicortical interfragmentary (IF) screw, 1.5 mm lag technique screw, 2.0 mm bicortical IF screw, or 2.0 mm lag technique screw. Biomechanical testing was performed to measure post cyclic displacement and load to failure. Data was analyzed using one-way analysis of variance (ANOVA). There was no significant difference among the fixation techniques with regard to both displacement and ultimate failure strength. There was a slight trend for a higher load to failure with the 2.0 mm IF screw and 2.0 mm lag screw compared to the 1.5 mm IF and 1.5 mm lag screws, but this was not significant. Our results support previously established clinical data that bicortical interfragmentary screw fixation is an effective treatment option for oblique metacarpal fractures. This technique has clinical importance because it is an option to appropriately stabilize the often small and difficult to control fracture fragments encountered in metacarpal fractures.
| S-EPMC2584215 | biostudies-other
Project description:Management of distal humeral fractures remains to be one of the most challenging aspects in trauma surgery. Low profile plating systems with variable angle screw fixation represent a crucial advancement to the established angular stable locking plates with considerable attention in current research. The aim of the prospective randomized trial was to review the preliminary results and patients' outcome following treatment with these newly developed implants and to rule out potential differences in fracture treatment of two different plating systems.Twenty patients with distal humeral fractures (AO 13-A1 - AO 13-C3) were included in the current study since 2014. After completing the randomization plan, patients were distributed into two groups for different variable angle locking plates (DePuy Synthes® VA-LCP vs. Medartis® Aptus Elbow). Functional elbow scoring (ROM, MEPS, QuickDASH) served as primary outcome parameter, while radiological fracture consolidation served as secondary outcome parameter. Follow-ups were conducted 6 weeks, 12 weeks, 6 months and 12 months after the operation.Seventeen of 20 patients (85%) concluded all follow-up examinations. Postoperative elbow extension deficiencies showed significant differences between the two groups in all follow-up examinations with a mean of Ø 18 +/- 7.4 degrees in the DePuy Synthes® VA-LCP group compared to a mean of Ø 6.5 +/- 7.5 degrees in the Medartis® Aptus Elbow group (p?=?0.002) 12 months postoperatively. Functional scoring showed a disparate pattern. The Medartis® Aptus Elbow group achieved significantly better MEP scores during follow-up. However, the analysis of the QuickDash revealed better results of the DePuy Synthes® VA-LCP group in the first half and better results of the Medartis® Aptus Elbow group in the second half of the follow-up examination instead.Considering the complexity of distal humeral fractures, the usage of anatomically preshaped low profile variable angle locking plates for operative treatment leads to good clinical results. Even though there might be some advances of the Medartis® Aptus Elbow plating system concerning postoperative ROM and elbow function, a consistent difference in the overall clinical outcome between the two plating systems could not be detected.https://clinicaltrials.gov/ct2/show/NCT03272490 Retrospectively Registered 1. September 2017.
| S-EPMC5745613 | biostudies-literature
Project description:IntroductionWe hypothesised that the use of a polyaxial locking plate design offers the same clinical benefits as a monoaxial locking plate system following distal femoral osteoporotic/periprosthetic fracture fixation.MethodA multicentre prospective randomised pilot trial was conducted. Inclusion criteria were patients over 60 years with a displaced osteoporotic or periprosthetic distal femoral fracture. Details documented included time to union, complications, reinterventions and functional outcomes according to the Oxford knee score and EuroQol EQ-5D. Analysis of factors influencing an early fracture healing response was performed between those with clear features of radiological callus formation at three months. Statistical analysis was performed using a logistic regression model with multiple covariates assessed for each plate system (1:1 ratio) over a follow-up period of one year.ResultsForty patients (34 females) with a mean age of 77 (60-99) were recruited. Four patients deceased within the first six months. Twenty-five patients united by the six month follow-up. Six more patients progressed to union between six and nine months. Five patients developed non-union (two patients had implant failure; one in each group) and all underwent revision surgery. Malunion was evident in two cases, one with 15° of valgus (monoaxial plate), and one with 12° of recurvatum (polyaxial plate). Between the two plate systems, statistical analysis revealed no significant differences in most of the recorded parameters. Radiological features of early bone healing were present when the surgical approach was smaller (p = 0.015), and when a greater working length of the bridging plate was present (p = 0.016).ConclusionBoth plate systems demonstrated good union rates and limited implant related complications. Good reduction, mechanically sound construct and respect of the local fracture biology was more important than the particular plate design characteristics.
| S-EPMC6470115 | biostudies-literature