Conventional Reconstruction Plates Research Articles

Anatomical Posterior Acetabular Plate Versus Conventional Reconstruction Plates for Acetabular Posterior Wall Fractures: A Comparative Study.

Background: Functional recovery following the surgical fixation of acetabular posterior wall fractures remains a challenge. This study compares outcomes of posterior wall fracture reconstruction using an anatomical posterior acetabular plate (APAP) versus conventional reconstruction plates. Methods: Forty patients with acetabular fractures involving the posterior wall or column underwent surgery, with 20 treated using APAPs (APAP group) and 20 with conventional pelvic reconstruction plates (control group). Baseline patient characteristics, intraoperative blood loss and time, reduction quality, postoperative function, and postoperative complications were compared using appropriate non-parametric statistical tests. A general linear model for repeated measures analysis of variance was employed to analyze trends in functional recovery. Results: No significant differences were observed in baseline characteristics. APAP significantly reduced surgical time by 40 min (186.5 ± 51.0 versus 225.0 ± 47.7, p =0.004) and blood loss (695 ± 393 versus 930 ± 609, p = 0.049) compared to conventional plates. At 3 and 6 months following surgery, the APAP group exhibited higher functional scores (modified Merle d'Aubigné scores 10 ± 1.8 versus 7.8 ± 1.4, p < 0.001; 13.4 ± 2.8 versus 10.1 ± 2.1, p = 0.001), converging with the control group by 12 months (modified Merle d'Aubigné scores 14.2 ± 2.6 versus 12.7 ± 2.6, p = 0.072; OHS 31.6 ± 12.3 versus 30.3 ± 10.1, p = 0.398). Radiologically, the APAP group demonstrated superior outcomes (p = 0.047). Complication and conversion rates to hip arthroplasty did not significantly differ between groups (10% versus 15%, p = 0.633). Conclusions: The use of an APAP in reconstructing the posterior acetabulum significantly reduces surgical time, decreases intraoperative blood loss, and leads to earlier functional recovery compared to conventional reconstruction plates. The APAP provides stable fixation of the posterior wall and ensures the durable maintenance of reduction, ultimately yielding favorable surgical outcomes.

Biomechanical Comparison of Fixation Methods for Posterior Wall Fractures of the Acetabulum: Conventional Reconstruction Plate vs. Spring Plate vs. Variable Angle Locking Compression Plate.

Background and Objectives: Acetabular fractures, though infrequent, present considerable challenges in treatment due to their association with high-energy trauma and poor prognoses. Posterior wall fractures, the most common type among them, typically have a more favorable prognosis compared to other types. Anatomical reduction and stable fixation of the posterior wall are crucial for optimal treatment outcomes. This study aimed to biomechanically compare three commonly used fixation methods for posterior wall fractures of the acetabulum-a conventional reconstruction plate, a spring plate, and a 2.7 mm variable angle locking compression plate (VA-LCP). Materials and Methods: The study utilized 6 fresh-frozen cadavers, yielding 12 hemipelvises free from prior trauma or surgery. Three fixation methods were compared using a simple acetabulum posterior wall fracture model. Fixation was performed by an orthopedic specialist, with prebending of plates to minimize errors. Hemipelvises were subjected to quasi-static and cyclic loading tests, measuring fracture gap, stiffness, and displacement under load. Results: It showed no significant differences in fracture gap among the three fixation methods under cyclic loading conditions simulating walking. However, the conventional reconstruction plate exhibited a greater stiffness compared to the spring and variable angle plates. Fatigue analysis revealed no significant differences among the plates, indicating a similar stability throughout cyclic loading. Despite differences in stiffness, all three fixation methods demonstrated adequate stability under loading conditions. Conclusions: While the conventional reconstruction plate demonstrated a superior stiffness, all three fixation methods provided sufficient stability under cyclic loading conditions similar to walking. This suggests that postoperative limitations are unlikely with any of the three methods, provided excessive activities are avoided. Furthermore, the variable angle plate-like the spring plate-offers an appropriate stability for fragment-specific fixation, supporting its use in surgical applications. These findings contribute to understanding the biomechanical performance of different fixation methods for acetabular fractures, facilitating improved surgical outcomes in challenging cases.

Which implant is better for the fixation of posterior wall acetabular fractures: A conventional reconstruction plate or a brand-new calcaneal plate?

BackgroundIncreased posterior wall acetabular fractures among older adults, require precise treatment to restore stability to the joint, lower the risk of degenerative arthritis, and enhance overall functional recovery. The purpose of this study was to compare the fixation stability and mechanical characteristics of calcaneal buttress plate and conventional reconstruction plate under different loading condition. MethodsTypical acetabular posterior wall fractures were created on twenty synthetic hemipelvis models. They were fixed with calcaneus plate and reconstruction plate. Dynamic and static tests were performed. Displacements of fracture line and stiffness were calculated. FindingsAfter dynamic loading, calcaneus plate fixation has significantly less displacement than the reconstruction plate on the superior posterior wall. Under static loading condition, the calcaneus plate group has significantly less displacement than the reconstruction plate group on the inferior posterior part of the fracture. The average stiffness values of the calcaneus plate group and the reconstruction plate group were 265.16±53.98 N/mm and 167.48±36.87 N/mm, respectively and a statistically significant difference was found between the two groups. InterpretationThe calcaneal plate group demonstrated better stability along the fracture line after dynamic and static loading conditions. Especially when the fragment was on the acetabulum's superior posterior, inferior posterior, and inferior rim, Calcaneal buttress plates offer biomechanically effective choices.

Finite element analysis of biplanar customized reconstruction plates for lateral and central segmental defects of mandible

The purpose of this study is to compare biplanar custom mandibular reconstruction plates with locking reconstruction plates in bridging central and lateral mandibular segmental defects by using the finite element method. Central and two different types of lateral segmental defects were created on mandibular model that was generated from computed tomography of a male patient. Segmental defects were fixed with conventional locking reconstruction plates and two different custom designed plates with caudobuccal and dorsobuccal cover. Stress formation on hardware and screws, strain on bone under masticatory simulation were evaluated with a finite element model. The stress values on plate and screws were higher in conventional reconstruction plate than custom plates. Simulations of central segmental defect revealed maximum von Mises stresses of 643.62 MPa and 101.83 MPa in conventional reconstruction plate and biplanar plate, respectively. Biplanar plates revealed slightly higher von Mises stresses than extended surfaced biplanar plates. The screws close to resection area were exposed to higher stress than farther screws for whole groups. In conventional reconstruction plate, the maximum von Mises stress values of fixation screws were 268.66 MPa and 95 MPa for central segmental defect and lateral segmental defect, respectively. The study reveals that the biplanar custom reconstruction plates had a favourable effect on stress distribution and can enhance function and aesthetics as supporting mandible and flaps from two different planes.

Simultaneous reduction and fixation using an anatomical suprapectineal quadrilateral surface plate through modified Stoppa approach in superomedially displaced acetabular fractures

Treatment of superomedially displaced acetabular fractures including a quadrilateral surface (QLS) is challenging. We present a surgical technique using an anatomical suprapectineal QLS plate through the modified Stoppa approach and report the availability of this plate to treat this fracture type along with the surgical outcomes. Sixteen consecutive patients (14 men and 2 women) who underwent surgical treatment using an anatomical suprapectineal QLS plate through a modified Stoppa approach for superomedially displaced acetabular fractures between June 2018 and June 2020, were enrolled retrospectively. These fractures included 11 both-column fractures and 5 anterior-column and posterior hemitransverse fractures, which were confirmed on preoperative 3-dimensional computed tomography. Surgical outcomes were clinically assessed using the Postel Merle d’Aubigné (PMA) score and visual analog scale (VAS) score at the final follow-up, and radiological evaluations were performed immediately after the operation and at the final follow-up. For comparative analysis, 23 patients who underwent internal fixation with the conventional reconstruction plate through modified ilioinguinal approach between February 2010 and May 2018, were selected. This control group was composed of 18 both-column fractures and 5 anterior-column and posterior hemitransverse fractures. The follow-up period was at least 1 year in all patients. The mean operation time and blood loss was 109 min, and 853 ml, respectively, whereas 236 min, and 1843 ml in control group. Anatomical reduction was achieved in 14 (87.5%) patients, while imperfect reduction was achieved in the remaining 2 patients. At the final follow-up, radiographic grades were excellent, fair, and poor in 14 patients (87.5%), one, and one, respectively. The mean PMA score was 16.1 (range 13–18) and the mean VAS score was 1.0 (range 0–3). No secondary reduction loss or implant loosening was observed. However, 2 patients underwent conversion to total hip arthroplasty (THA) due to post-traumatic arthritis and subsequent joint pain. No other complications were observed. In the comparative analysis, radiological outcome showed a significant relationship with the conversion to THA (p = 0.013). Shorter operation time and less blood loss were significantly observed in the QLS plate fixation group through the modified Stoppa approach compared with the conventional reconstruction plate fixation group through modified ilioinguinal approach (p < 0.001, respectively). Simultaneous reduction and fixation using an anatomical suprapectineal QLS plate through the modified Stoppa approach may be a viable technique in superomedially displaced acetabular fractures along with shorter operation time and less blood loss.

Clinical Outcomes and Cost Analysis of Fibula Free Flaps: A Retrospective Comparison of CAD/CAM versus Conventional Technique

Simple SummaryCurrent planning techniques, including computer-aided design/computer-aided manufacturing (CAD/CAM), offer ways to plan reconstructive surgery that optimize aesthetic outcomes and functional rehabilitation. In addition, the use of these techniques promotes safety and reduces the duration of operations. This study compares both the cost of CAD/CAM technology and the clinical results with those of the conventional technique in remodeling the fibula for mandibular reconstruction.(1) Background: A decrease in operative time can not only improve patient outcomes through a reduction in the risk of developing complications but can also result in cost savings. The aim of this study is to determine whether there an intraoperative time gain can be achieved by using the preoperative virtual planning of mandibular reconstruction using a free fibula flap compared with freehand plate bending and osteotomies. (2) Methods: A retrospective comparative study was carried out in the Oral and Maxillofacial Department of La Paz University Hospital, Madrid, Spain. The study compared 18 patients in the CAD/CAM group with 19 patients in the conventional freehand group. A comparison was made between the total surgical time, the comorbidities, and the hospital stay. The resource consumption was estimated using a cost analysis. (3) Results: Although CAD/CAM was a statistically more expensive procedure in the perioperative phase, no significant differences were observed in total health care costs between the two groups. There was a non-significant trend towards an increase in complications with conventional reconstruction plates compared to patient-specific plates (PSI). (4) Conclusions: CAD/CAM technology and a 3D printed cutting guide offer a significantly shorter surgical time, which is associated with a reduction in hospital days, PACU days, and complications. The cost of CAD/CAM technology is comparable to that of the conventional freehand technique.

Comparison of the Accuracy and Clinical Parameters of Patient-Specific and Conventionally Bended Plates for Mandibular Reconstruction.

ObjectivesThis retrospective study compared two mandibular reconstruction procedures—conventional reconstruction plates (CR) and patient-specific implants (PSI)—and evaluated their accuracy of reconstruction and clinical outcome.MethodsOverall, 94 patients had undergone mandibular reconstruction with CR (n = 48) and PSI (n = 46). Six detectable and replicable anatomical reference points, identified via computer tomography, were used for defining the mandibular dimensions. The accuracy of reconstruction was assessed using pre- and postoperative differences.ResultsIn the CR group, the largest difference was at the lateral point of the condyle mandibulae (D2) -1.56 mm (SD = 3.8). In the PSI group, the largest difference between preoperative and postoperative measurement was shown at the processus coronoid (D5) with +1.86 mm (SD = 6.0). Significant differences within the groups in pre- and postoperative measurements were identified at the gonion (D6) [t(56) = -2.217; p = .031 <.05]. In the CR group, the difference was 1.5 (SD = 3.9) and in the PSI group -1.04 (SD = 4.9). CR did not demonstrate a higher risk of plate fractures and post-operative complications compared to PSI.ConclusionFor reconstructing mandibular defects, CR and PSI are eligible. In each case, the advantages and disadvantages of these approaches must be assessed. The functional and esthetic outcome of mandibular reconstruction significantly improves with the experience of the surgeon in conducting microvascular grafts and familiarity with computer-assisted surgery. Interoperator variability can be reduced, and training of younger surgeons involved in planning can be reaching better outcomes in the future.

Biomechanical comparison of locking and non-locking patient-specific mandibular reconstruction plate using finite element analysis

Patient-specific mandibular reconstruction plate (PSMRP), as one of the patient-specific implants (PSIs), offers a host of benefits to mandibular reconstruction. Due to the limitation of fabricating screw hole threads in the PSMRP, 3D printed PSMRP is applied to the non-locking system directly in the mandibular reconstruction with bone graft regardless of the locking system. Since the conventional manual-bending reconstruction plate (CMBRP) provides better fixation in the locking system, it needs to be validated whether the locking PSMRP performs better than the non-locking PSMRP in the patient-specific mandibular reconstruction. Thereupon, the purpose of this study was to compare the biomechanical behavior between the locking and non-locking PSMRP. Finite element analysis (FEA) was used to conduct the biomechanical comparison between the locking PSMRP and non-locking PSMRP by simulating the momentary incisal clenching through static structural analysis. Mandible was reconstructed through the virtual surgical planning, and subsequently a 3D model of mandibular reconstruction assembly, including reconstructed mandible, PSMRP, and fixation screws, was generated and meshed for the following FEA simulations. In the form of equivalent von Mises stress, equivalent elastic strain, and total deformation, the locking PSMRP demonstrated its higher strengths of preferable safety, desirable flexibility, and anticipated stability compared with the non-locking PSMRP, indicated by much lower maximum stress, lower maximum strain and equivalent displacement. Locking PSMRP/screw system provides a better fixation effect to the patient-specific mandibular reconstruction than the non-locking one as a result of its productive fixation nature. FEA plays a paramount role in pre-validating the design of PSMRP through the biomechanical behavior evaluation in static structural analysis.

PARAMETRIC MANDIBLE RECONSTRUCTION PLATE

This study investigated the feasibility of a parametric mandible reconstruction plate in order to reduce surgical lead time, improve fit, and reduce residual stresses. The parametric plates were generated on the basis of simulated cephalometric measurements. A finite element analysis and a reconstruction plate/mandible fit test were performed on several combinations to determine whether the parametric plate provided a suitable alternative to conventional reconstruction plates in terms of fit and structural performance. The results indicated that the parametric plate is structurally superior to a conventional plate. The comparison test indicated that the parametric plate provides a reasonable approximation of mandible geometry.

Novel finite element-based plate design for bridging mandibular defects: Reducing mechanical failure.

IntroductionWhen the application of a free vascularised flap is not possible, a segmental mandibular defect is often reconstructed using a conventional reconstruction plate. Mechanical failure of such reconstructions is mostly caused by plate fracture and screw pull‐out. This study aims to develop a reliable, mechanically superior, yet slender patient‐specific reconstruction plate that reduces failure due to these causes.Patients and MethodsEight patients were included in the study. Indications were as follows: fractured reconstruction plate (2), loosened screws (1) and primary reconstruction of a mandibular continuity defect (5). Failed conventional reconstructions were studied using finite element analysis (FEA). A 3D virtual surgical plan (3D‐VSP) with a novel patient‐specific (PS) titanium plate was developed for each patient. Postoperative CBCT scanning was performed to validate reconstruction accuracy.ResultsAll PS plates were placed accurately according to the 3D‐VSP. Mean 3D screw entry point deviation was 1.54 mm (SD: 0.85, R: 0.10–3.19), and mean screw angular deviation was 5.76° (SD: 3.27, R: 1.26–16.62). FEA indicated decreased stress and screw pull‐out inducing forces. No mechanical failures appeared (mean follow‐up: 16 months, R: 7–29).ConclusionReconstructing mandibular continuity defects with bookshelf‐reconstruction plates with FEA underpinning the design seems to reduce the risk of screw pull‐out and plate fractures.

A Modified Method Using Double Computed Tomography Scan Procedure to Maintain Mandibular Width in Mandibular Reconstruction.

The purpose of this study was to evaluate the use of a modified template system and double computed tomography scan procedure to maintain mandibular width in cases of mandibular reconstruction. Ten patients who underwent mandibular reconstruction with a fibular flap were enrolled. The surgeries were planned with a computer-aided surgical simulation (CASS) planning method. Following double computed tomography scan procedure, the template system was designed in a computer and was fabricated using a three-dimensional printing technique. The cutting guides were designed with the holes of the conventional reconstruction plate on the remnant mandibular segments. After surgery, the outcome evaluation was compared by first superimposing the post-operative computed tomography model onto the planned model and then measuring the differences between the planned and actual outcomes. All surgeries were completed successfully using the template system. With the use of the templates, the largest linear root-mean-square deviation (RMSD) between the planned and post-operative remnant segments was 1.01 mm, and the largest angular RMSD was 4.05°. The authors conclude that this template system and double computed tomography scan procedure provides a reliable method to maintain mandibular width in mandibular reconstruction using a fibular flap.

Complication rates and clinical outcomes of osseous free flaps: a retrospective comparison of CAD/CAM versus conventional fixation in 128 patients

Studies evaluating plate-related complications in patient-specific versus conventional fixation systems in free flap surgery are lacking. This was a retrospective study of 128 osseous free flaps with a minimum follow-up of 12 months. Wound healing disorders, plate exposure, fixation failure, and subtotal osseous union were recorded and evaluated statistically by univariate and regression analysis. Complication rates were as follows: wound healing disorders 33.6% (computer-aided design and computer-aided manufacturing (CAD/CAM) vs. conventional: 35.1% vs. 33.0%); plate exposure 21.9% (29.7% vs. 18.7%); fixation failure 7.0% (8.1% vs. 6.6%); subtotal osseous union 36.7% (45.9% vs. 33.0%). Radiotherapy (P<0.001) and more than two segments (P=0.026) were independent variables for the overall complication rate and were negatively correlated with the dental implantation rate. The time between diagnosis and ablative surgery was increased by 11.0days in the CAD/CAM group (34.2±16.2days vs. 23.2±12.0 days; P=0.002). Rates of dental rehabilitation were not significantly different (35.1% vs. 44.0%, P=0.358). On average, 3.2±1.7 dental implants were placed into flap segments. Plate-related complications were increased with radiotherapy and multisegment flaps. There was a non-significant trend towards increased complications with patient-specific plates in comparison to conventional reconstruction plates.

Fixation of Displaced Acetabular Fractures With an Anatomic Quadrilateral Surface Plate Through the Stoppa Approach.

Satisfactory fixation for displaced acetabular fractures involving the quadrilateral surface remains difficult to obtain with conventional reconstruction plates. To achieve minimally invasive management of fractures of the quadrilateral surface, the authors designed a type of anatomic quadrilateral surface plate (AQSP). A retrospective study to assess the therapeutic results of the AQSP was performed at their institution. A total of 26 patients with quadrilateral surface fractures fixed with an AQSP through the Stoppa approach from February 2014 to February 2015 were included in this study. There were 16 men and 10 women with a mean age of 37.5 years. The patients were followed for a mean of 28.81 months (range, 24-36 months). The mean operative time was 98.85±16.08 minutes, and the mean intraoperative blood loss was 353.85±124.84 mL. Postoperative radiographs and computed tomography scans showed that anatomic and good reductions were obtained in 88.46% (23 patients) and 11.54% (3 patients) of the patients, respectively. Screw loosening was not observed. All of the fractures healed well at a mean of 3.54 months. Two cases of obturator nerve injury and 1 case of corona mortis rupture were observed. However, permanent complications were not observed. The mean Merle d'Aubigné score at final follow-up was 16.38±1.33 points. The authors conclude that satisfactory fixation with the AQSP system can be achieved through the Stoppa approach. [Orthopedics. 2019; 42(2):e180-e186.].

Clinical experience with a novel structure designed bridging plate system for segmental mandibular reconstruction: The TriLock bridging plate

The innovative TriLock Bridging Plate System (Medartis AG, Switzerland) was developed to reduce common complications related to conventional mandibular reconstruction plates. The novelties regarding the plating system concern the cross-strut structure in the centerpiece, the bendable side elements and the reduction of the plate's thickness to 2.0 mm 4 different models are available, which cover lateral and central segmental mandibular defects. The plating system has only been introduced at selected maxillofacial units so far and clinical assessment is still lacking. Thus, the aim of the study was to analyze the novel Bridging Plate system in terms of its clinical applicability, rate of trimming and postoperative outcomes in a first investigation over 6 months. The study includes 25 patients with segmental mandibular resection, who underwent reconstruction with TriLock Bridging Plates. According to the assessment parameters, excellent clinical applicability was stated in 48%. The overall trimming rate was found to be 88%. Mostly adaptions to the distal bendable elements of lateral plates were performed. The occurrence of postoperative complications was 16%. Plate fracture occurred in 4%. With reference to the results, the novel plating system represents a viable method for segmental mandibular reconstruction, however, further evaluation is needed, for a more detailed analyzation.

Pre-contoured locking plates vs. conventional reconstruction plates in AO type C distal humerus fractures: A prospective randomized study

Background: Reconstruction plates have been used from a long time for fixation of distal humerus fractures. Locking plates are increasingly used now-a-days. The aim of this study is to compare the radiological and functional outcome of AO Type C distal humerus fracture treated with pre-contoured locking plates and conventional reconstruction plates. Material and Methods: A total of 25 patients of AO type C distal humerus fracture were enrolled for the study during 2016- 2018. Out of 25 patients, 14 were treated using locking plates and 11 were treated using reconstruction plates. Patients were followed up at 2 weeks, 6 weeks, 3 months, 6 months and 12 months post operatively. Radiological assessment was done by follow-up X-rays at 3, 6 and 12 months. Mayo Elbow Performance Score was used for assessment of functional outcome at 3, 6 and 12 months post-operatively. Results: The mean duration of surgery and hospital stay was similar in both the groups. The mean Range of motion and MEPS score was significantly higher in locking plate group as compared to conventional reconstruction plates at 3 months post operatively. However both of them were similar at 6 months and 12 months post operatively. 93% union rate in locking plate group and 9% union rate in reconstruction plate group were seen at the end of 12 months follow-up. Excellent and/or good results were obtained in 93% in locking plate group which is significantly higher than reconstruction plate group in which only 82% patients had excellent and/ or good results. Conclusion: Locking plates has advantage over reconstruction plates in early mobility and greater functional outcome.

Is it necessary to plate all posterior wall fractures of the acetabulum?

Background Posterior wall injuries represent the commonest type of acetabular fractures. It could be isolated fractures or − more commonly − associated with hip dislocation with varying degrees of displacement and comminution. Being intra-articular injuries affecting the congruency and stability of the hip joint, 30% of patients with such injuries have poor outcomes. Accurate fracture reduction with stable fixation is the standard way for achieving satisfactory results. This study aims to evaluate the suitability and efficacy − in light of the clinical and radiological results − of using only screws for fixation of certain posterior wall fractures through a limited exposure using the Kocher-Langenbeck approach. Patients and methods This study included 16 cases of displaced posterior wall fractures with single, sizable fragment or multiple, noncomminuted fragments treated with open reduction and internal fixation using only screws through a limited exposure using the Kocher-Langenbeck approach. In 14 cases, fractures were associated with hip dislocation whereas the last 2 cases had isolated posterior wall injuries. Radiological assessment according to Matta and Heeg criteria and clinical evaluation according to Postel score were done postoperatively and throughout the follow-up period that extended for a mean duration of 18.9±6.7 months. Results Clinically satisfactory results (excellent and good) were reported in 14 cases, representing 87.5% of the studied cases. One case was rated fair and one case was rated poor, so unsatisfactory results (fair and poor) were reported in two cases, representing 12.5% of the studied cases. According to the modified criteria of Matta, 12 cases had excellent reduction and four cases had good reduction, and according to the radiographic grading criteria by Heeg, 14 cases were excellent with a normal-appearing hip joint compared with the healthy side; one case was fair with joint narrowing less than 50% compared with the other healthy side with no osteophytes and viable head; and one case was rated as poor with advanced degenerative changes, head subluxation, and severe avascular necrosis. No cases developed heterotopic ossification or implant failure. Conclusion Fixation by only screws through a limited exposure could be a simple and reliable fixation method for certain posterior wall fractures with less soft tissue dissection and intraoperative and postoperative complications, with comparable clinical and radiological results to the more complex fixation methods using conventional reconstruction plates or locked plates.

Comparison of conventional reconstruction plate versus direct metal laser sintering plate: an in vitro mechanical characteristics study

BackgroundAdditive manufacturing (AM) technology has helped to achieve several advances in the medical field, particularly as far as fabrication of implants is concerned. But the application of direct metal laser sintering (DMLS) bone plate is quite limited due to the indeterminate mechanical property. The purposes of this study were to characterize the biomechanical properties of the polished DMLS reconstruction plate and to compare these with the properties of commonly applied implants and to find whether the mechanical performance of DMLS plate meets the requirements for clinical application.MethodsIn this study, we fabricated two groups of plates by DMLS and computer numerical control (CNC) techniques. After that, we polished all samples and investigated their roughness, components, hardness, static bending, and torsional performance. Moreover, cyclic bending tests and fractographic analysis were conducted. Statistical comparisons of the group by means of monotonic test data were made, and a qualitative comparison was performed to assess failures in fatigue.ResultsWe found no differences in surface roughness or components after polishing, but the DMLS plate hardness is 7.42% (p < 0.01) greater than that of the CNC plates. Compared with the CNC plates, the DMLS plate static bending and torsional performance were significantly greater. In a dynamic test, the DMLS plates survived 106, 106, 32,731, and 33,264 cycles under 0.6, 0.8, 0.9, and 1 kN cyclic loads, respectively, while the CNC plates survived 106, 106, 106, and 283,714 cycles.ConclusionsThese results indicate that the mechanical performances of the DMLS plate are stronger, and the strength under fatigue tests is sufficient. DMLS implant has great potential and may become a better choice for clinical use in the future. However, direct application of these AM instruments in the operating room requires further validation including animal and clinical experiment.

Clinical analysis of MatrixMANDIBLE Preformed Reconstruction Plate design

MatrixMANDIBLE Preformed Reconstruction Plates (MMPRPs) were developed to overcome laborious bending procedures of conventional reconstruction plates. The design comprises three sizes with a nonbendable centerpiece and two bendable sections (proximal and distal). According to the surgical protocol unnecessary parts are trimmed after the last used screw hole. In the present retrospective study postoperative radiographs from 130 patients (average age 63 years) that received treatment with MMPRPs were assessed. There was no statistical correlation between plate-size, location (left/right) or age. 82.98% of the small and 91.80% of the medium MMPRPs were trimmed by at least the terminal screw hole of the ramus part. In all patients receiving a large MMPRP, the terminal screw hole of the ramus was unused accordingly all inserted large MMPRPs were trimmed by at least the terminal screw hole. The majority of the bridged defects were located within the area of the body indicating a feasible plate design. With the emergence of solid free form fabrication of Ti-alloys and economic need to reduce the waste of resources this study may help to further improve the MMPRP design and prevent the loss of medical-grade titanium.

Clinical efficacy of ITS universal locking plate for treatment of comminuted mid-shaft clavicular fracture

Objective To evaluate the clinical efficacy of ITS universal locking plate for treatment of comminuted midshaft clavicle fractures.Methods The clinical data of 74 patients with comminuted mid-shaft claviclar fractures,who were treated from Jan.2008 to Oct.2013,were retrospectively analyzed.The patients included 32 treated with ITS universal locking plate and 42 with reconstruction plate.The operation time,fracture healing time,postoperative Constant-Murly scores and postoperative complications were compared between the two treatment groups.Results Baseline data had no statistical difference between the two groups.The operation was successful in both groups,and the average operation time was(39.5±9.1)min in ITS universal locking plate group and(47.4±10.2)min in reconstruction plate group,showing significant difference(P0.01).No significant differences were found for the mean healing time([13.5±3.0]weeks vs[13.3±3.8]weeks)or the Constant-Murly scores([91.1±3.0]vs[90.2±2.7])between the two groups.There was no delayed union,nonunion,screw loosening,plate fracture or other complications in ITS universal locking plate group;while one patient had postoperative pain in his shoulder and three others reported difficulty in shoulder mobility.In reconstruction plate group,delayed union was reported in 3cases,nonunion in 1case,screw loosening in 3cases,plate fracture in 1case,postoperative shoulder pain in 4cases,and difficulty in shoulder mobility in 2cases.The total postoperative complication rates were significantly different between the two groups(13%vs 33%,P0.05).Conclusion ITS universal locking plate has a satisfactory effect for treatment of comminuted mid-shaft claviclar fractures,and it is superior to the conventional reconstruction plate.

Biomechanical Comparison of Different Stabilization Constructs for Unstable Posterior Wall Fractures of Acetabulum. A Cadaveric Study

PurposeOperative treatment of unstable posterior wall fractures of acetabulum has been widely recommended. This laboratory study was undertaken to evaluate static fixation strength of three common fixation constructs: interfragmentary screws alone, in combination with conventional reconstruction plate, or locking reconstruction plate.MethodsSix formalin-preserved cadaveric pelvises were used for this investigation. A posterior wall fracture was created along an arc of 40–90 degree about the acetabular rim. Three groups of different fixation constructs (two interfragmentary screws alone; two interfragmentary screws and a conventional reconstruction plate; two interfragmentary screws and a locking reconstruction) were compared. Pelvises were axial loaded with six cycles of 1500 N. Dislocation of superior and inferior fracture site was analysed with a multidirectional ultrasonic measuring system. Results: No statistically significant difference was found at each of the superior and inferior fracture sites between the three types of fixation. In each group, the vector dislocation at superior fracture site was significantly larger than inferior one.ConclusionsAll those three described fixation constructs can provide sufficient stability for posterior acetabular fractures and allow early mobilization under experimental conditions. Higher posterior acetabular fracture line, transecting the weight-bearing surface, may indicate a substantial increase in instability, and need more stable pattern of fixation.