Synthetic Tibiae Research Articles

A Biomechanical Comparison Study of Plate-Nail and Dual-Plate Fixation in AO/OTA 41-C2 Tibial Plateau Fractures.

This study's purpose was to evaluate the biomechanical performance of plate-nail and dual-plate fixation for the treatment of AO/OTA 41-C2 tibial plateau fractures. Twenty synthetic tibias were selected and randomly divided into a plate-nail group (n = 10) and a dual-plate group (n = 10). After the artificial tibias were osteotomized to simulate AO/OTA 41-C2 tibial plateau fractures in both groups, the plate-nail and the dual-plate methods, respectively, were used for fixation, and then axial compression loading, three-point bending, torsion, and axial failure tests were carried out. The data of each group were recorded and statistically analyzed. In the axial compression test, the average stiffness of the plate-nail group was higher than that of the dual-plate group (p < 0.05). The displacement generated in the plate-nail group was significantly smaller than that in the dual-plate group (p < 0.05). In the resisting varus test, the stress of the plate-nail group was significantly higher than that of the dual-plate group (p < 0.05). In the resisting valgus test, the stress of the plate-nail group was slightly higher than that of the dual-plate group, but the difference was not statistically significant (p > 0.05). In the static torsion test, the load applied to the plate-nail group was smaller than that of the dual-plate group when rotated to 5° (p < 0.05). In the axial compression failure test, the average ultimate load of the plate-nail group was significantly higher than that of the dual-plate group (p < 0.05). The treatment of AO/OTA 41-C2 tibial plateau fractures with plate-nail fixation is superior to that with dual-plate fixation in resisting axial stress and preventing tibial varus deformity, while dual-plate fixation has better resisting torsional ability.

Feasibility Study of Experimental Protocol for the Time-Dependent Mechanical Response of Synthetic Tibia.

In this research, an experimental biomechanics construct was developed to reveal the mechanics of distal tibial fracture by submitting synthetic tibiae to cyclic loading, resulting in a combined stress state due to axial compression and bending loads. The synthetic tibia was fixed at the knee but allowed to rotate in the coronal and sagittal planes at the ankle. The first three loading regimes lasted for 4000 cycles/each, and the final until ultimate failure. After 12k±80 cycles, the observed failure patterns closely resembled distal tibial fractures. The collected data during cyclic loading were fitted into a phenomenological model to deduce the time-dependent response of the synthetic tibiae. Images were also collected and analyzed using digital image correlation to deduce the full-field state of strain. The latter revealed that longitudinal strain contours extended in the proximal-distal direction. The transverse strain contours exemplified a medial-to-lateral distribution, attributed to the combined contributions of the Poisson's effect and the flexural deformation from axial and bending components of the applied load, respectively. The experimental construct, full-field characterization, and data analysis approaches can be extended to elucidate the effect of different fixation devices on the overall mechanical behavior of the bone and validate computational models in future research.

Biomechanics and finite element analysis comparing posterior T-plates with LCP for fixation of posterolateral tibial plate fractures.

Objective: The treatment for posterolateral tibial plateau fractures (PTPF) have been subjects of controversy. We conducted a study to improve the fixation of PTPF through a lateral approach. Methods: We utilized 40 synthetic tibias and categorized the fracture models into five groups based on the locking compression plate (LCP) and T-distal radius plate (TPP) via various forms of fixation with screws through the posterolateral (PL) fracture fragments. I: Two-screw fixation using two locking screws (LPTL). Ⅱ: Two-screw fixation with both variable angle locking screws (LPTV). Ⅲ: One-screw fixation with one locking screw (LPOL). Ⅳ: One-screw fixation with one locking screw and two anteroposterior lag screws (LPOLTL). Ⅴ: a distal radius plate with three locking screws (TPP). Biomechanical tests were conducted to observe the axial compression displacement of the PL fracture fragments at force levels of 250N, 500N, and 750N, as well as to determine the failure load and the axial stiffness for each respective group. Results: Under a 750N load condition, the displacements within the five experimental groups exhibited the following trend: Ⅴ < Ⅱ < Ⅰ< Ⅳ < Ⅲ. However, there were no significant differences between Group V and Group II, Group I and Group IV (p > 0.05), and only Group Ⅲ demonstrated a displacement exceeding 3mm. The failure load and the axial stiffness exhibited the same trend. Conversely, statistical significance was identified among the remaining group compared with Group Ⅲ (p < 0.05). Regarding the finite element analysis, the maximum displacements for the five models under the load of 750N exhibited the following trend: Ⅴ < Ⅱ < Ⅰ< Ⅳ < Ⅲ. The following trends were observed in maximum von Mises stresses for these models under the load of 750N: Ⅴ < Ⅱ < Ⅳ< Ⅰ < Ⅲ. Conclusion: It is crucial to address the inadequate mechanical strength associated with single screw fixation of LCP for fixing PL fractures in a clinical setting. The biomechanical strength of two-screw fixation surpasses that of single-screw fixation. Introducing variable-angle screws can further enhance the fixation range. Furthermore, the addition of two lag screws threaded from anterior to posterior can compensate the mechanical stability, when PL fracture is fixed with single screw in clinic.

Biomechanics and finite element analysis of a novel plate designed for posterolateral tibial plateau fractures via the anterolateral approach

Surgical management of posterolateral tibial plateau (PLTP) fractures is challenging. One reason for this challenge is the lack of suitable internal fixation devices. Our aim was to introduce a novel plate via the anterolateral approach for managing PLTP fractures. The biomechanical testing and finite element analysis (FEA) were performed. PLTP fracture models were created using synthetic tibias (n = 10 within each group). These models were randomly assigned to three groups (groups A-C) and fixed with the lateral locking plate, the posterior buttress plate, and the novel plate, respectively. The vertical displacement of the posterolateral fragments was evaluated using biomechanical testing and FEA under axial loads of 250 N, 500 N, and 750 N. We also evaluated the stress distribution and maximum stress of each fracture model using FEA. Biomechanically, under the same loads of 250 N, 500 N, or 750 N, the vertical displacement was significantly different among the three fixation groups (p ≤ 0.001). FEA data indicated that the maximum displacement from group A to C was 3.58 mm, 3.23 mm, and 2.78 mm at 750 N, respectively. The maximum stress from group A to C was 220.88 MPa, 194.63 MPa, and 156.77 MPa in implants, and 62.02 MPa, 77.71 MPa, and 54.15 MPa in bones at 750 N, respectively. The general trends at 250 N and 500 N were consistent with those at 750 N. Based on our biomechanical and FEA results, the novel plate could be a good option for treating PLTP fractures. The novel plate showed stable and reliable features, indicating its suitability for further clinical application.

Preservation of the posterolateral cortex may not affect the biomechanical stability of lateral intra-articular varus osteotomy of the proximal tibia

BackgroundLateral intra-articular varus osteotomy is an L-shaped osteotomy of the lateral tibial condyle to correct mild knee valgus and lateral plateau malunion of the proximal tibia. In order to minimize injury, it was modified to preserve the posterolateral cortex and the upper tibiofibular joint. The aim of this study was to evaluate the stability of modified lateral intra-articular varus osteotomy by comparing the biomechanical strength with lateral intra-articular varus osteotomy. MethodsTwenty-four synthetic tibia models were divided into 2 groups based on osteotomy type. Each model was then fixed with 2 commonly used plate systems. Biomechanical tests were conducted to measure parameters including construct stiffness, wedge displacement, and the number of failed specimens, and the results were compared among different groups. FindingsNo significant difference was found in construct stiffness among all groups (P > 0.05). There was also no significant difference in wedge displacement among all groups (P > 0.05). When an axial load of 1500 N was applied, the number of failed specimens showed no significant difference among all groups (P > 0.05). The main failure pattern was additional fracture lines on the lateral tibial plateau. InterpretationThe findings indicate that there was no significant difference in stability between the 2 groups under the tested loading conditions. Furthermore, it appears that preserving the posterolateral cortex may have no impact on biomechanical stability.

Stability of Three-Dimensional Printed Custom-Made Metaphyseal Cone for Tibial Bone Defects Reconstruction: A Finite Element Analysis and Biomechanical Study.

The reconstruction of bone defects in tibial revision knee arthroplasty is challenging. In this study, we evaluated the primary stability of a novel three-dimensional (3D)-printed custom-made metaphyseal cone for Anderson Orthopedic Research Institute (AORI) IIb or III bone defect reconstruction in tibial revision knee arthroplasty using the combination of finite-element analysis and biomechanical experiments. In the finite-element analysis, AORI II b and III medial tibial bone defects were designed at varying depths. A novel 3D-printed custom-made metaphyseal cone was designed and used to reconstruct the bone defect with or without a stem in simulated revision total knee arthroplasty (RTKA). A no-stem group and a stem group were established (based on whether a stem was used or not). Von Mises stress and micromotion were calculated with varying depths of bone defects, ranging from 5 mm to 35 mm, and then micromotions at the bone-implant interface were calculated and compared with the critical value of 150 μm. In the biomechanical experiment, the no-stem group was used, and the same bone defects were made in four synthetic tibias using patient-specific instruments. Micromotions at the bone-implant interface were investigated using a non-contact optical digital image correlation system and compared with the critical value of 150 μm. When the bone defect was <30 mm, micromotions at the bone-implant interface in the finite-element analysis were all below 150 μm both in the stem groups and no-stem groups, whereas those in the biomechanical experiment were also below 150 μm in the no-stem group. The 3D-printed custom-made metaphyseal cone in RTKA has excellent primary stability and does not require stems in reconstructing tibial AORI type IIb or III bone defects with a depth of <30 mm.

Biomechanical analysis of tibial plateau posterolateral fracture fragment fixation and introduction of a lateral tibia plateau hook plate system

BackgroundFixing the posterolateral fragments of tibial plateau fractures has been challenging owing to potential neurovascular injuries and fibular head blocks. Several surgical approaches and fixation techniques have been reported, with distinct limitations. We propose a novel lateral tibia plateau hook plate system and compare its biomechanical stability with other fixation methods. MethodsTwenty-four synthetic tibia models were simulated to present posterolateral tibial plateau fractures. These models were randomly assigned to three groups. Group A models were fixed with the lateral tibia plateau hook plate system, Group B with variable-angle anterolateral locking compression plates, and Group C with direct posterior buttress plates. The models’ biomechanical stability was evaluated using static (gradually increased axial compressive loads) and fatigue (cyclically loaded from 100 to 600 N for 2000 cycles each) tests. ResultsGroups A and C models exhibited comparable axial stiffness, subsidence load, failure load, and displacement in the static test. Group A model exhibited higher subsidence and failure loads than Group B model. Groups A and C models exhibited comparable displacement at 100 N cyclic loading in the fatigue test. Group C model was more stable at higher loads. Group C model endured the highest subsidence cycle numbers, followed by Groups A and B models. ConclusionsThe lateral tibia plateau hook plate system provided similar static biomechanical stability as the direct posterior buttress plates and comparable dynamic stability under limited axial loading. This system is a potential posterolateral treatment choice owing to its convenience and safety, in treating tibia plateau fractures.

Biomechanical comparison of intramedullary nail and plate osteosynthesis for extra-articular proximal tibial fractures with segmental bone defect.

Purpose: Proximal tibial fractures are common, but the current available internal fixation strategies remain debatable, especially for comminuted fractures. This study aimed to compare the biomechanical stability of three internal fixation strategies for extra-articular comminuted proximal tibial fractures. Methods: A total of 90 synthetic tibiae models of simulated proximal tibial fractures with segmental bone defects were randomly divided into three groups: Single lateral plating (LP), double plating (DP) and intramedullary nailing (IN). Based on the different number of fixed screws, the above three groups were further divided into nine subgroups and subjected to axial compression, cyclic loading and static torsional testing. Results: The subgroup of intramedullary nailing with five proximal interlocking screws showed the highest axial stiffness of 384.36 ± 35.00N/mm. The LP group obtained the lowest axial stiffness performance with a value of 96.59 ± 16.14N/mm. As expected, the DP group offered significantly greater biomechanical stability than the LP group, with mean static axial stiffness and mean torque increasing by approximately 200% and 50%, respectively. According to static torsional experiments, the maximum torque of the DP subgroup was 3,308.32 ± 286.21N mm, which outperformed all other groups in terms of torsional characteristics. Conclusion: Utilizing more than four distal screws did not provide improved biomechanical stability in the LP or DP groups, while a substantial increase in the biomechanical stability of DP was obtained when an additional medial plate was used. For the intramedullary nailing group, increasing the number of proximal interlocking screws could significantly improve biomechanical stability, and the intramedullary nailing with three proximal interlocking screws had similar static and cyclic stiffness as the DP group. The intramedullary nailing with five proximal screws had better axial stability, whereas DP had better torsional stability.

Cerclage Wiring Improves Biomechanical Stability in Distal Tibia Spiral Fractures Treated by Intramedullary Nailing

Partial weight-bearing after operatively treated fractures has been the standard of care over the past decades. Recent studies report on better rehabilitation and faster return to daily life in case of immediate weight-bearing as tolerated. To allow early weight-bearing, osteosynthesis needs to provide sufficient mechanical stability. The purpose of this study was to investigate the stabilizing benefits of additive cerclage wiring in combination with intramedullary nailing of distal tibia fractures. In 14 synthetic tibiae, a reproducible distal spiral fracture was treated by intramedullary nailing. In half of the samples, the fracture was further stabilized by additional cerclage wiring. Under clinically relevant partial and full weight-bearing loads the samples were biomechanically tested and axial construct stiffness as well as interfragmentary movements were assessed. Subsequently, a 5 mm fracture gap was created to simulate insufficient reduction, and tests were repeated. Intramedullary nails offer already high axial stability. Thus, axial construct stiffness cannot be significantly enhanced by an additive cerclage (2858 ± 958 N/mm NailOnly vs. 3727 ± 793 N/mm Nail + Cable; p = 0.089). Under full weight-bearing loads, additive cerclage wiring in well-reduced fractures significantly reduced shear (p = 0.002) and torsional movements (p = 0.013) and showed similar low movements as under partial weight-bearing (shear 0.3 mm, p = 0.073; torsion 1.1°, p = 0.085). In contrast, additional cerclage had no stabilizing effect in large fracture gaps. In well-reduced spiral fractures of the distal tibia, the construct stability of intramedullary nailing can be further increased by additional cerclage wiring. From a biomechanical point of view, augmentation of the primary implant reduced shear movement sufficiently to allow immediate weight-bearing as tolerated. Especially, elderly patients would benefit from early post-operative mobilization, which allows for accelerated rehabilitation and a faster return to daily activities.

Comparação biomecânica entre placa de TPLO modificada, placa bloqueada e construção placa-pino intramedular aplicadas medialmente em modelo de fratura proximal em tíbias sintéticas caninas

ABSTRACT The aim of this study was to develop a modified tibial plateau leveling osteotomy (TPLO) plate and to compare its biomechanical properties with a locking compression plate (LCP) and plate-rod constructs for the stabilization of experimentally induced gap fractures in canine synthetic tibias. The tibial models were assigned to either repair with a modified TPLO plate (Group 1), locking compression plate construct (Group 2), or plate-rod construct (Group 3). The specimens were loaded to failure in axial compression, three-point mediolateral and craniocaudal bending. There was no statistical difference between the three groups regarding stiffness (N/mm) and deformation (mm) in axial compression. The modified TPLO plate achieved load to failure similar to the plate-rod construct in craniocaudal bending. There was no significant difference between groups on mediolateral bending tests regarding load to failure and deformation. Furthermore, there was no significant difference in stiffness between groups 1 and 2. In conclusion, the modified TPLO plate had similar mechanical properties to LCP and plate-rod construct in the axial compression and bending tests. Nonetheless, clinical studies with a large population of dogs are required to determine the value of this new implant in proximal tibial fracture repair.

The effect of the distance between the end point of the osteotomy and the lateral cortex on the lateral cortical hinge fracture in medial opening-wedge high tibial osteotomy

Background The purpose of this study was to compare the effects of different distances between the end point of the osteotomy and the lateral cortex on the risk of lateral cortical fracture in the medial opening-wedge high tibial osteotomy (MOWHTO) procedure. Methods Eighteen synthetic tibia models were used. Saw cuts were performed on the test models (n=6 for all groups). Wedge gap distance and wedge opening load were evaluated using compression tests. Findings The mean maximum gap distance without a lateral cortical fracture was 19.90 mm in Group 5, 15.49 mm in Group 10, and 11.23 mm in Group 15. The differences between Group 5 and Group 10, Group 5 and Group 15, and Group 10 and Group 15 were statistically significant. The mean load just before the fracture was 13.24 N in Group 5, 18.31 N in Group 10, and 26.16 N in Group 15. The difference between Group 5 and Group 15 was statistically significant. No significant difference was observed between Group 10 and both Group 5 and Group 15. Interpretation As the end point of the osteotomy is brought gradually closer to the lateral cortex, wider gaps can be opened without a lateral cortical fracture. Thus, higher angle corrections can be achieved more safely by bringing the end point of the osteotomy closer to the lateral cortex, which should be preferred to reduce the risk of a lateral cortical hinge fracture during the MOWHTO procedure, from a clinical viewpoint.

Lateral locking plate plus antero-posterior lag screws techniques for the management of posterolateral tibial plateau fracture: preliminary clinical results and biomechanical study.

To date, there is no consensus on the optimal surgical strategy for the treatment of posterolateral tibial plateau fracture (PLF). This study introduced a novel, simple technique for treating PLF with a lateral locking plate plus antero-posterior lag screws (LPpLS). We conducted a retrospective case series of 42 patients (Female/Male 19/23) with PLF treated with LPpLS between 1 July 2016 and 30 June 2019. Several pre- and postoperative outcomes were recorded, including operative time, intraoperative blood loss, CT findings, HSS, and ROM. For biomechanical studies, seventy synthetic tibiae with a simulated posterolateral split fracture were divided into seven groups. The biomechanical evaluation included displacement measurement at axial compression and fatigue testing. Forty-two eligible patients were followed up for an average of 18months (range 14-21months). Postoperative radiographs and CT showed good positioning of plates and screws, no fracture fragment loss, and normalarticularsurfaces in all 42 cases. The biomechanical study showed that the axial stiffness of LPpLS was in the same fashion as the posterior buttress plate and better than the other fixation methods (P < 0.05). Additionally, the LPpLS group had a smaller displacement of fracture fragments along the X-axis (medial to lateral direction) than the BP group (P < 0.01). The LPpLS technique could implement good reconstruction of the PLF, showing satisfactory therapeutic effect. The biomechanical evaluation demonstrated that the LPpLS had better stability in three-dimensional directions for PLF than other fixation strategies.

Fixation of Extra-articular Proximal Tibia Fractures: Biomechanical Comparison of Single and Dual Implant Constructs.

This biomechanical study seeks to define the relative effectiveness of contemporary single and dual implant constructs for fixation of an extra-articular proximal tibia fracture model. An extra-articular proximal tibia fracture model was created using synthetic tibias. Four constructs were tested. Constructs included (1) lateral locked plate (LLP), (2) intramedullary nail (IMN), (3) combined LLP and IMN (PN), and (4) LLP and medial locked plate. Specimens were axially loaded through the medial plateau to evaluate construct stiffness and the ability to resist varus collapse. Dual implant constructs were stiffer than single implant constructs in this model. Although DP and PN were stiffer than IMN at all loads tested, the difference was notable only for DP at higher loads. Isolated LLP provided insufficient stability to be tested at higher loads. Dual plate fixation provides the greatest resistance to varus collapse. In the clinical setting, consideration must be given to the fracture morphology, desired construct stiffness, and soft-tissue envelope in selecting the optimal construct to be used.

Evaluation of Bone Consolidation in External Fixation with an Electromechanical System

The monitoring of fracture or osteotomy healing is vital for orthopedists to help advise, if necessary, secondary treatments for improving healing outcomes and minimizing patient suffering. It has been decades since osteotomy stiffness has been identified as one main parameter to quantify and qualify the outcome of a regenerated callus. Still, radiographic imaging remains the current standard diagnostic technique of orthopedists. Hence, with recent technological advancements, engineers need to use the new branches of knowledge and improve or innovate diagnostic technologies. An electromechanical system was developed to help diagnose changes in osteotomy stiffness treated with the external fixator LRS Orthofix®. The concept was evaluated experimentally and numerically during fracture healing simulation using two different models: a simplified model of a human tibia, consisting of a nylon bar with a diameter of 30 mm, and a synthetic tibia with the anatomical model from fourth-generation Sawbones®. Moreover, Sawbones® blocks with different densities simulated the mechanical characteristics of the regenerated bone in many stages of bone callus growth. The experimental measurements using the developed diagnostic were compared to the numerically simulated results. For this external fixator, it was possible to show that the displacement in osteotomy was always lower than the displacement prescribed in the elongator. Nevertheless, a relationship was established between the energy consumption by the electromechanical system used to perform callus stimulus and the degree of osteotomy consolidation. Hence, this technology may lead to methodologies of mechanical stimulation for regenerating bone, which will play a relevant role for bedridden individuals with mobility limitations.

Evaluation of a crescent saw guide for tibial plateau-leveling osteotomy: An ex vivo study.

To evaluate the effectiveness of a novel crescent-shaped tibial plateau-leveling osteotomy (TPLO) saw guide (crescent guide) to assist with saw control in novice participants. Ex vivo study. Synthetic bones (n=54) and medium sized dog pelvic limbs (n=36). The 6 participants (interns and residents) without any prior experience performing a TPLO each performed 9 osteotomies on synthetic tibia models, and 6 osteotomies in cadaveric limbs of medium-sized dogs. Osteotomies made with the crescent guide were compared with those made with a standard jig and a radial saw guide with a jig. Osteotomy angulation, distance of eccentricity (DOE), and medial tibial cortical damage (synthetic bone models only) were measured from calibrated photographs. Participants rated their experiences with each technique. There was no difference in the DOE, coronal or axial osteotomy angulation between the 3 alignment devices for synthetic bone models or cadavers. Average medial cortical damage with the crescent guide (3.8 ± 7.3 mm2 ) was lower than with the radial guide (35.7 ± 27 mm2 ) and standard jig (51.2 ± 63.2 mm2 ) guides (P=<.01). Five of 6 participants preferred the crescent guide over the standard jig and radial guide. There was no difference in accuracy of osteotomy positioning but using the crescent guide resulted in lower cortical damage and more favorable participant perceptions. The crescent guide may improve control of the radial saw during TPLO in novice surgeons but does not appear to aid accurate osteotomy positioning.

Using Haptic Feedback in a Virtual Reality Bone Drilling Simulation to Reduce Plunge Distance.

BackgroundBone drilling is a procedure that demands a high level of dexterity, fine motor skills and spatial awareness from the operating surgeon. An important consideration when drilling bone is minimising soft tissue damage. There are numerous causes of drilling associated soft tissue injury, of which most concerning is drilling into the tissue beyond the far cortex as unseen injury can occur. This is known as plunging.ObjectivesThe objective of this study was to evaluate the impact of haptic feedback in virtual reality (VR) simulation-based training. The acquisition of drilling skill was assessed by changes to their drill plunge depth.Study Design & MethodsThe participants in the study were medical students, doctors and biomedical scientists. Participants were randomly allocated into two groups. One group had simulation with haptic feedback as part of their VR simulated learning, whereas the second group undertook the same VR simulation but did not receive haptic feedback during the simulation. Following completion of the simulated bone drilling protocol, a bone drilling exercise took place. Each participant was allowed to drill a synthetic tibia bone five times and then the plunge depth was measured. We quantified outcome in the form of plunge depth.Results There were four participants in each group. The average plunge distance in the group who were able to practice with haptic assisted VR simulation was 46mm (range: 37-56mm), the average plunge distance in the non-haptic group was 79mm (range: 44-136mm). Results showed an average reduction of 33mm in plunge depth from users in the haptic group compared to the non-haptic group.Conclusion Bone drilling simulation with haptic feedback may be an effective simulator of the motor skills that would be required to perform this action on a live patient. The study results suggest that there could be a reduction in soft tissue damage for users trained in VR simulations with haptic feedback.

Stay Ipsilateral: An Analysis of Tibial Tunnel Distance Between Cruciate Ligament Reconstruction and Posterior Meniscal Root Repair

PurposeTo establish mean distance or identify intersection between tibial tunnels for posterior meniscal root repair in the setting of anterior cruciate ligament (ACL) or posterior cruciate ligament (PCL) reconstruction.MethodsTwelve cadaver knees and 12 solid foam synthetic tibiae were used. ACL and PCL tunnels were drilled for single-bundle reconstruction, and both medial and lateral posterior root repair tunnels were drilled. Specimens underwent computed tomography scanning and shortest distances between tunnels in all planes were measured by 2 readers. Distances were compared between groups using a t-test.ResultsIn ACL reconstruction, the medial meniscal root tunnel was not significantly closer to the cruciate tunnel when drilled from either medial or lateral side (P = .333). The lateral meniscal root tunnel was significantly closer when drilled from medial compared to lateral side (P < .001). In PCL reconstruction, both medial (P = .037) and lateral (P = .028) meniscal root tunnels were significantly closer to the PCL tunnel when drilled from the contralateral side of the tibia.ConclusionThis study demonstrates that posterior meniscal root repair tunnels are often placed within a few millimeters and can even intersect cruciate ligament reconstruction tunnels in the proximal tibia.Clinical RelevanceThe information in this study may assist surgeons in planning for cruciate ligament reconstruction with concomitant posterior meniscal root repair.

Biomechanical evaluation of different types of lateral hinge fractures in medial opening wedge high tibial osteotomy

BackgroundLateral hinge fractures are common complications in the medial opening wedge high tibial osteotomy for treatment of knee osteoarthritis. The rehabilitation protocols are decided depending on the remaining stability following these fractures. This study aimed to evaluate the biomechanical properties of different types of lateral hinge fractures in medial opening wedge high tibial osteotomy. MethodsTwenty synthetic tibia models were used as test samples. A 10-mm bone wedge was removed from the medial side of the proximal tibias to create the bone defect. The samples were then divided into 4 groups: (1) intact lateral hinge; (2) Takeuchi type I fractures; (3) type II fractures; and (4) type III fractures. After fixation with a locking plate, the stability parameters including construct stiffness, wedge displacement, and construct strength were tested under compressive forces and compared among the 4 groups. FindingsNo statistical difference was found in the construct stiffness among the 4 groups (P = 0.78). The type III fractures had the largest wedge displacement compared with the other 3 groups. The failure loads on average were significantly reduced in the type III fractures compared with those with intact hinge (P < 0.01) and in type I fractures (P = 0.04). No statistical difference was observed between the type I fractures and the intact hinge in terms of wedge displacement or failure loads. InterpretationThe type III fractures were the most unstable and patients with these fractures should be managed cautiously. Delayed weightbearing and/or additional fixation should be considered.

Treatment of Isolated Posterolateral Tibial Plateau Fracture with a Horizontal Belt Plate through the Anterolateral Supra-Fibular-Head Approach.

The posterolateral tibial plateau fracture was not easy to be exposed and fixed with usual techniques. The aim of this study was to investigate the biomechanical stability and clinical outcome of the isolated posterolateral tibial plateau fracture fixed with a single horizontal belt plate through the anterolateral supra-fibular-head approach. Fracture models were created by 18 synthetic tibias and fixed with three different fixation modes. Each group was fixed and tested on the loading machine, and final vertical displacement of the fragment was detected and calculated. Clinically, a retrospective analysis of 12 cases of posterolateral tibial plateau fracture from January 2013 to December 2017 was performed. There were 8 males and 4 females, aged 33-72 years, with an average age of 49.6 years. Isolated posterolateral tibial plateau fractures were identified according to preoperative X-ray and computed tomography scan. Through the modified anterolateral supra-fibular-head approach, the fracture was reduced and fixed by a prebending T-shaped distal radius plate and rafting screws, with bone substitute grafting or autogenous iliac bone implantation. Patients were followed up to a minimum one year of time period, and the outcome was evaluated clinically and radiologically. The biomechanical study shows that horizontal belt plate fixation for the isolated PL tibial plateau fracture can provide sufficient stability, allowing early knee functional exercise and partial weight bearing. For clinical case series, the average operation time in this group was 73.3 ± 10.2 mins (range: 55-90), and the average duration of hospitalization was 9.1 ± 3.3 days (range: 5-16). Patients were followed up for 12-24 months with an average of 16.5 months, and all patients achieved radiological fracture union after an average of 13.7 weeks. At one year after operation, the average knee score of the Hospital for Special Surgery (HSS) scale was 93.2 ± 4.2 points(range: 90-98), the average score of SMFA was 21.1 ± 5.6 points (range: 14-31), and the average knee range of motion (ROM) was 121.48° ± 8.88° (range: 105°-135°). There were 8 cases that were very satisfied and 3 cases that were satisfied with the operation. For an isolated posterolateral tibial plateau fracture, the supra-fibular-head approach can fully expose the fracture site; the horizontal belt plate fixation of the fracture is stable and reliable to allow for early-stage knee rehabilitation, and the outcome of medium-term clinical follow-up was satisfactory.

Supplemental cerclage wiring in angle stable plate fixation of distal tibial spiral fractures enables immediate post-operative full weight-bearing: a biomechanical analysis

PurposeDistal tibial fractures generally require post-operative weight-bearing restrictions. Especially geriatric patients are unable to follow these recommendations. To increase post-operative implant stability and enable early weight-bearing, augmentation of the primary osteosynthesis by cerclage is desirable. The purpose of this study was to identify the stabilizing effects of a supplemental cable cerclage following plate fixation of distal tibial spiral fractures compared to solitary plate osteosynthesis.MethodsIn eight synthetic tibiae, a reproducible spiral fracture (AO/OTA 42-A1.1c) was stabilized by angle stable plate fixation. Each specimen was statically loaded under combined axial and torsional loads to simulate partial (200 N, 2 Nm) and full (750 N, 7 Nm) weight-bearing. Tests were repeated with supplemental cable cerclage looped around the fracture zone. In a subsequent stepwise increased dynamic load scenario, construct stiffness and interfragmentary movements were analyzed.ResultsWith supplemental cable cerclage, construct stiffness almost tripled compared to solitary plate osteosynthesis (2882 ± 739 N/mm vs. 983 ± 355 N/mm; p < 0.001). Under full weight-bearing static loads, a supplemental cerclage revealed reduced axial (− 55%; p = 0.001) and shear movement (− 83%; p < 0.001), and also lowered shear movement (− 42%; p = 0.001) compared to a solitary plate under partial weight-bearing. Under dynamic loads supplemental cerclage significantly reduced axial (p = 0.005) as well as shear movements (p < 0.001).ConclusionSupplemental cable cerclage significantly increases fixation stiffness and reduces shear movement in distal tibial spiral fractures. This stabilizing effect enables from a biomechanical point of view immediate mobilization without any weight-bearing restrictions, which may improve the quality of care of orthopedic patients and may trigger a change towards early weight-bearing regimes, especially geriatric patients would benefit from.