A biomechanical study comparing a raft of 3.5 mm cortical screws with 6.5 mm cancellous screws in depressed tibial plateau fractures

Subchondral rafting wires reduce tibial plateau fracture subsidence

PURPOSE

To determine if subchondral rafting wires retained as adjunctive tibial plateau fracture fixation affect postoperative articular subsidence.

METHODS

A retrospective cohort study was conducted at one Level 1 trauma center and one academic university hospital. Consecutive adults with closed, displaced OTA/AO 41B/C tibial plateau fractures treated between 2018 and 2023 with open reduction internal fixation were included. Patients who were not ambulatory, with contralateral injuries limiting weight bearing, and without follow-up radiographs of the injured extremity were excluded. The intervention was retention of subchondral rafting wires as definitive fixation. The primary outcome was linear articular surface subsidence between postoperative and follow-up AP knee radiographs. Linear subsidence was compared between groups using Welch's two sample t test. Associations of linear subsidence with patient, injury, and treatment characteristics were assessed by multivariable linear regression.

RESULTS

We identified 179 patients of a mean age of 44 ± 14 years, of whom 15 (8.4%) received subchondral rafting wires. Median follow-up was 121 days. No patients who received rafting wires as definitive implants experienced linear subsidence ≥ 2 mm, while 22 patients (13.4%) who did not receive rafting wires experienced linear subsidence ≥ 2 mm (p = 0.130). Subchondral rafting wires were associated with less linear subsidence (0.3 mm [95% confidence interval - 0.3-0.9 mm] vsersus 1.0 mm [- 0.9-2.9 mm], p < 0.001). The depth of linear subsidence was significantly associated on multivariable regression with male sex, depressed plateau area, active smoking, and retained rafting wires.

CONCLUSION

Subchondral rafting wires were associated with a small reduction in articular subsidence after internal fixation of tibial plateau fractures. Routine rafting wires may be useful for patients and fractures at high risk of articular subsidence.

Comparison of the results of the synthesis of Schatzker II and III tibial plateau fractures by screwing versus plate

PURPOSE

Lateral tibial plateau fractures with depression are the most common. Their treatment is currently surgical. Many therapeutic procedures have been described. Our aim is to evaluate the results of open surgery and to compare the two internal fixation methods used: lag screw versus plates.

MATERIALS AND METHODS

This is a retrospective comparative study of two series of tibial plateau fractures Schatzker types II and III treated surgically over a period of ten years with two different methods: Group A: Internal fixation using screws for 86 patients. Group B: Internal fixation using plates for 71 patients. Functional and anatomical results were assessed according to Rasmussen's clinical and radiological scores.

RESULTS

The patients' average age was 44 years (range from 18 to 76). The male gender was predominant (104 males and 53 females). Road traffic accidents were the most common aetiology with over two thirds of the cases. The fractures were type Schatzker II in 61% of the cases. The mean follow-up was five years. Although the clinical and radiological Rasmussen scores were better in group A (internal fixation with lag screws), those differences were statistically insignificant (p = 0.6 and p = 0.8). Group A clinical and radiological scores were 26.06 and 16.57, respectively and those of group B were 25.72 and 16.45. We noticed more sepsis and skin complications and a longer operating time (95 min versus 70 min) in group B patients with a statistically significant difference. None of the patients of our series had bone grafting.

CONCLUSION

For Schatzker II and III fractures, an internal fixation with lag screws would be preferable when possible especially in the case of a pure depression fracture. It yields satisfactory results with a shorter operating time and less complication rate.

Plate osteosynthesis combined with bone cement provides the highest stability for tibial head depression fractures under high loading conditions

Older patients sustaining tibial head depression fractures often cannot follow the post-operative rehabilitation protocols with partial weight-bearing of the affected limb, leading to osteosynthesis failure, cartilage step-off and arthritis development. Therefore, the aim of this study was to analyse the biomechanical performance of different types of osteosyntheses alone and in combination with bone cement simulating cyclically high loading conditions of tibial head depression fractures. Lateral tibial head depression fractures (AO: 41-B2.2; Schatzker type III) were created in synthetic bones and stabilized using three different osteosyntheses alone and in combination with a commonly used bone cement (chronOS™): 2 screws, 4 screws in the jail technique and a lateral angle-stable buttress plate. After fixation, the lateral tibial plateau was axially loaded in two, from each other independent testing series: In the first test protocol, 5000 cycles with 500 N and in the end load-to-failure tests were performed. In the second test protocol, the cyclic loading was increased to 1000 N. Parameters of interest were the displacement of the articular fracture fragment, the stiffness and the maximum load. The osteosyntheses revealed a higher stiffness in combination with bone cement compared to the same type of osteosynthesis alone (e.g., 500 N level: 2 screws 383 ± 43 N/mm vs. 2 screws + chronOs 520 ± 108 N/mm, increase by 36%, p < 0.01; 4 screws 368 ± 97 N/mm vs. 4 screws + chronOS 516 ± 109 N/mm, increase by 40%, p < 0.01; plate: 509 ± 73 N/mm vs. plate + chronOs 792 ± 150 N/mm, increase by 56%, p < 0.01). Bone cement reduced the displacement of the plate significantly (500 N level: plate: 8.9 ± 2.8 mm vs. plate + chronOs: 3.1 ± 1.4 mm, reduction by 65%, p < 0.01; 1000 N level: 16.9 ± 3.6 mm vs 5.6 ± 1.3 mm, reduction by 67%, p < 0.01). Thus, the highest stiffness and lowest displacement values were found when using the plate with bone cement in both loading conditions (500 N level: 2 screws + chronOs 3.7 ± 1.3 mm, 4 screws + chronOs 6.2 ± 2.4 mm; 1000 N level: 2 screws + chronOs 6.5 ± 1.2 mm, 4 screws + chronOs 5.7 ± 0.8 mm). From a biomechanical perspective, plate osteosynthesis of tibial head depression fractures should always be combined with bone cement, provides higher stability than 2-screw and 4-screw fixation and is a valid treatment option in cases where extraordinary stability is required.

Newly designed anterolateral and posterolateral locking anatomic plates for lateral tibial plateau fractures: a finite element study

BACKGROUND

Lateral column tibial plateau fracture fixation with a locking screw plate has higher mechanical stability than other fixation methods. The objectives of the present study were to introduce two newly designed locking anatomic plates for lateral tibial plateau fracture and to demonstrate their characteristics of the fixation complexes under the axial loads.

METHODS

Three different 3D finite element models of the lateral tibial plateau fracture with the bone plates were created. Various axial forces (100, 500, 1000, and 1500 N) were applied to simulate the axial compressive load on an adult knee during daily life. The equivalent maps of displacement and stress were output, and relative displacement was calculated along the fracture lines.

RESULTS

The displacement and stresses in the fixation complexes increased with the axial force. The equivalent displacement or stress map of each fixation under different axial forces showed similar distributing characteristics. The motion characteristics of the three models differed, and the max-shear stress of trabecula increased with the axial load.

CONCLUSIONS

These two novel plates could fix lateral tibial plateau fractures involving anterolateral and posterolateral fragments. Motions after open reduction and stable internal fixation should be advised to decrease the risk of trabecular microfracture. The relative displacement of the posterolateral fragments is different when using anterolateral plate and posterolateral plate, which should be considered in choosing the implants for different posterolateral plateau fractures.

Biomechanical evaluation of interfragmentary compression at tibia plateau fractures in vitro using different fixation techniques: a CONSORT-compliant article

Reliable osteosynthesis of intraarticular fractures depends on lasting interfragmentary compression. Its amount differs in the applied fixation method. The interfragmentary compression of cancellous and cortical lag screws and angle stable locking plates was quantified in an osteoporotic and non-osteoporotic synthetic human bone model.A split fracture of the lateral tibia plateau (AO/OTA type 41-B1.1) was mimicked by an osteotomy in right adult synthetic human tibiae with hard or soft cancellous bone. Specimens were fixed with either two 6.5 mm cancellous, four 3.5 mm cortical lag screws, or 3.5 mm LCP proximal lateral tibia plate preliminary compresed by a reduction clamp (n = 5 per group). A pressure sensor film was used to register the interfragmentary compression. One-way analysis of variance (ANOVA) with Bonferroni post hoc correction was performed for statistical analysis (p < 0.05).Interfragmentary compression under reduction clamp was 0.59 ± 0.12 MPa in the non-osteoporotic and 0.55 ± 0.14 MPa in the osteoporotic group. The locking plate itself maintained the compression in non-osteoporotic (0.53 ± 0.11 MPa) and osteoporotic bone (0.50 ± 0.14 MPa). Four 3.5 mm cortical lag screws provided a compression of 1.69 ± 0.65 MPa in non-osteoporotic bone, being not significantly different to the osteoporotic bone group (1.43 ± 0.47 MPa, P = 1.0). Two 6.5 mm cancellous lag screws showed a significantly higher compression in non-osteoporotic (2.1 ± 0.59 MPa) compared to osteoporotic (0.77 ± 0.21 MPa, P < 0.01) bone.Angle stable locking plates maintained the compression preliminarily applied by a reduction clamp. Two 6.5 mm cancellous lag screws are especially suited for non-osteoporotic bone, whereas four 3.5 mm cortical screws exhibited comparable compression in both bone qualities.

Pullout strength of bone-patellar tendon-bone allograft bone plugs: a comparison of cadaver tibia and rigid polyurethane foam

PURPOSE

To compare the load-to-failure pullout strength of bone-patellar tendon-bone (BPTB) allografts in human cadaver tibias and rigid polyurethane foam blocks.

METHODS

Twenty BPTB allografts were trimmed creating 25 mm × 10 mm × 10 mm tibial plugs. Ten-millimeter tunnels were drilled in 10 human cadaver tibias and 10 rigid polyurethane foam blocks. The BPTB anterior cruciate ligament allografts were inserted into these tunnels and secured with metal interference screws, with placement of 10 of each type in each material. After preloading (10 N), cyclic loading (500 cycles, 10 to 150 N at 200 mm/min) and load-to-failure testing (200 mm/min) were performed. The endpoints were ultimate failure load, cyclic loading elongation, and failure mode.

RESULTS

No difference in ultimate failure load existed between grafts inserted into rigid polyurethane foam blocks (705 N) and those in cadaver tibias (669 N) (P = .69). The mean rigid polyurethane foam block elongation (0.211 mm) was less than that in tibial bone (0.470 mm) (P = .038), with a smaller standard deviation (0.07 mm for foam) than tibial bone (0.34 mm).

CONCLUSIONS

All BPTB grafts successfully completed 500 cycles. The rigid polyurethane foam block showed less variation in test results than human cadaver tibias.

CLINICAL RELEVANCE

Rigid polyurethane foam blocks provide an acceptable substitute for human cadaver bone tibia for biomechanical testing of BPTB allografts and offer near-equivalent results.

A biomechanical study comparing two fixation methods in depression fractures of the lateral tibial plateau in porcine bone

Background

A novel method of fixation has been described for the treatment of pure depression fractures of the lateral tibial plateau. Fracture fragments are elevated through a reamed transtibial tunnel. An interference screw is then passed into the tunnel to buttress fracture fragments from beneath. This method of fixation has perceived benefits but there have been no studies to demonstrate that the technique is biomechanically sound. The aim of our study is to compare traditional parallel, subchondral screw fixation with the use of an interference screw, assessing maintenance of fracture reduction following simulated post-operative loading, and overall construct strength.

Methods

Depression fractures of the lateral tibial plateau were simulated in 14 porcine knees. Fracture fragments were elevated through a reamed transtibial tunnel and samples were randomly assigned to a fixation method. 7 knees underwent traditional fixation with parallel subcortical cannulated screws, the remainder were stabilized using a single interference screw passed through the transtibial tunnel. Following preloading, each tibia was cyclically loaded from 0 to 500 Newtons for 5,000 cycles using a Nene testing machine. Displacement of the depressed fracture fragments were measured pre and post loading. Samples were then loaded to failure to test ultimate strength of each construct.

Results

The depression displacement of the fractures fixed using cannulated screws was on average 0.76 mm, in comparison to 0.61mm in the interference screw group (p=0.514). Mechanical failure of the cannulated screw constructs occurred at a mean of 3400 N. Failure of the transtibial interference screw constructs occurred at a mean of 1700 N (p<0.01). In both groups the mechanism of ultimate failure was splitting of the tibial plateau.

Conclusion

These results demonstrate the increased biomechanical strength of parallel, cannulated screws for depression fractures of the tibial plateau, however the use of a transtibial interference screw may be a viable method of fixation under physiological loads.

Tuberoplasty: minimally invasive osteosynthesis technique for tibial plateau fractures

Fractures of the tibial plateau are in constant progression. They affect an elderly population suffering from a number of comorbidities, but also a young population increasingly practicing high-risk sports and using two-wheeled vehicles. The objective of this study was therefore to propose a new technique for the treatment of this type of fracture. There are a variety of classical pitfalls of conservative treatment such as defective reduction resulting in early osteoarthritis and alignment defects. Conventional treatments lead to joint stiffness and amyotrophy of the quadriceps, caused by the open technique and late loading. We propose an osteosynthesis technique for tibial plateau fractures with minimally invasive surgery. A minimally invasive technique would be more appropriate to remedy all of the surgical drawbacks resulting from current practices. The surgical technique that we propose uses a balloon allowing progressive and total reduction, associated with percutaneous screw fixation and filling with polymethylmethacrylate (PMMA) cement. The advantages are optimal reduction, minimal devascularization, soft tissues kept intact, as well as early loading and mobilization. This simple technique seems to be a good alternative to conventional treatment. The most comminuted fractures as well as the most posterior compressions can be treated, while causing the least impairment possible. Arthroscopy can be used to verify fracture reduction and cement leakage. At the same time, it can be used to assess the associated meniscal lesions and to repair them if necessary.

Periarticular raft constructs and fracture stability in split-depression tibial plateau fractures

OBJECTIVES

To evaluate relative fracture stability yielded by screws placed above a lateral plate, as well as locking and non-locking screws placed through a plate in a split depression tibia plateau fracture model.

METHODS

Cadaver tibia specimens (mean age 74.1 years) were randomised across 3 groups: Groups 1: raft-construct outside the plate, 2: non-locking raft screws through the plate, and 3: locking raft screws through the plate. Displacement of the depressed fragment was recorded with force values from 400N to 1600N in increasing 400N increments. The force required to elicit lateral plateau fragment displacement of 5mm, 10mm, and 15mm was also recorded.

RESULTS

None of the mechanical testing results demonstrated statistical significance with p-values of <0.05. Cyclic testing of Groups 1, 2, and 3 at 400N revealed displacements of 0.54mm, 0.64mm, and 0.48mm, respectively. At 800N, displacements were 1.36mm, 1.4mm, and 1.4mm, respectively. At 1200N, displacements were 2.4mm, 1.9mm, and 2.1mm, respectively. At 1600N, displacements were 2.8mm, 2.5mm, and 2mm, respectively. Resistance to displacement data demonstrated the mean force required to displace the fracture 5mm in Groups 1, 2, and 3 were 250N, 330N, and 318N, respectively. For 10mm of displacement, forces required were 394N, 515N, and 556N, respectively. For 15mm of displacement, forces required were 681N, 853N, and 963N, respectively. Compared to combined groups using screws through the plate, Group 1 demonstrated lower displacement ≤800N, but demonstrated greater displacement >800N. Group 2 demonstrated greatest resistance to plateau displacement of 5mm compared to Group 1 or 3, while Group 3 was most resistant to greater displacement. The combined group using screws through the plate (Groups 2+3) was consistently more resistant than Group 1 at all levels of displacement.

CONCLUSIONS

Designs utilising screws through the plate trended towards statistically significant improved stability against plateau displacement relative to utilising screws outside the plate. Our study also suggests that there is no significant benefit of locking screws over non-locking screws in this unicondylar tibia plateau fracture model.

Arthroscopic management of tibial plateau fractures: surgical technique

Tibial plateau fractures are serious articular fractures that are challenging to treat. Arthroscopy-assisted percutaneous fixation is the treatment of choice in Schatzker types 1, 2, 3, and 4 fractures, as it ensures optimal reduction and stable fixation consistent with early mobilisation. The most reliable fixation method seems to be percutaneous cannulated screw fixation, which is less invasive than open plate fixation. In complex proximal tibial fractures, arthroscopy may allow an evaluation of articular fracture reduction, thereby obviating the need for extensive arthrotomy. Complementary stable fixation is crucial and should allow early mobilisation to reap the benefits of the arthroscopic assistance. This article aims to review the technical points that are useful to the successful video-assisted management of tibial plateau fractures.

Balloon tibioplasty: a useful tool for reduction of tibial plateau depression fractures

Reduction of the articular surface in displaced tibial plateau fractures is still challenging and may result in joint incongruence, leading to posttraumatic arthrosis. Conventional techniques use bone tamps and similar instruments, which can increase the surgical trauma due to their size. "Balloon tibioplasty" is a novel minimally invasive technique for the reduction of depressed tibial plateau fractures. We successfully applied an inflatable balloon, commercially available from kyphoplasty, to elevate the depressed articular fragments. This technique allowed for reduction of the depressed tibial plateau fragment without classic fenestration of the tibia, thereby minimizing surgical trauma. Furthermore, under fluoroscopic control, optimal centering of the expanding tibioplasty balloon allows a widespread and continuously increasing reduction force to the fracture area. After fluoroscopy or arthroscopic confirmation of reduction of the articular surface, the cavity resulting from tibioplasty was filled with ceramic bone cement through small incisions and fractures were fixed with a small fragment locking T-plate (3.5 mm). Balloon tibioplasty was applied in 5 patients with displaced tibial plateau fractures (OTA type B2/3). No intra- or postoperative complications were observed. This new technique may be a useful tool to facilitate the reduction of select depressed tibial fractures in the future.

Balloon osteoplasty--a new technique for reduction and stabilisation of impression fractures in the tibial plateau: a cadaver study and first clinical application

PURPOSE

Fractures of the tibial plateau are among the most severe injuries of the knee joint and lead to advanced gonarthrosis if the reduction does not restore perfect joint congruency. Many different reduction techniques focusing on open surgical procedures have been described in the past. In this context we would like to introduce a novel technique which was first tested in a cadaver setup and has undergone its successful first clinical application.

METHODS

Since kyphoplasty demonstrated effective ways of anatomical correction in spine fractures, we adapted the inflatable instruments and used the balloon technique to reduce depressed fragments of the tibial plateau.

RESULTS

The technique enabled us to restore a congruent cartilage surface and bone reduction.

CONCLUSIONS

In this technique we see a useful new method to reduce depressed fractures of the tibial plateau with the advantages of low collateral damage as it is known from minimally invasive procedures.

Inside out rafting K-wire technique for tibial plateau fractures

With the introduction of 3.5 anatomically pre-shaped plates, the rafting screw technique is gaining popularity in recent years for the management of lateral tibial plateau fractures with articular depression. To gain access to the depressed articular fragments, the split fragment is hinged open laterally. We elevate the depressed articular fragments to the normal level. The defect below is filled with bone graft or its substitutes. We then close the split fragment and apply rafting screws either through the screw holes of the plate or separately above the plate rather in a blind fashion. We therefore cannot be sure that the rafting screws are supporting the specific elevated fragments. For this reason some surgeons place the rafting screws from within and then close the lateral fragment over the screws. This so-called embedded rafting screw technique carries the risk of difficulty in removal, especially in case of an infection. Here we describe the inside out rafting technique to tackle this problem.

Tibial plateau fractures: A review

Tibial plateau fractures are uncommon injuries of the proximal tibia which vary in severity from minimally displaced stable injuries to high energy complex fractures with significant articular and metaphyseal comminution and severe associated soft tissue injuries. Following initial assessment and appropriate investigation a number of management options are available to the treating surgeon. We discuss the presentation, initial management and investigation as well as outlining the various treatment options with an emphasis on operative treatment. We further discuss the common complications and outcomes following tibial plateau fracture.

Bicondylar tibial fractures: Internal or external fixation?

Bicondylar fractures of the tibia, representing the Schatzker V and VI fractures represent a challenging problem. Any treatment protocol should aim at restoring articular congruity and the metaphyseo-diaphsyeal dissociation (MDD)-both of these are equally important to long-term outcome. Both internal and external fixations have their proponents, and each method of treatment is associated with its unique features and complications. We review the initial and definitive management of these injuries, and the advantages and disadvantages of each method of definitive fixation. We suggest the use of a protocol for definitive management, using either internal or external fixation as deemed appropriate. This protocol is based on the fracture configuration, local soft tissue status and patient condition. In a nutshell, if the fracture pattern and soft tissue status are amenable plate fixation (single or double) is performed, otherwise limited open reduction and articular surface reconstruction with screws and circular frame is performed.

Effect of Implant Design on Initial Stability of Tapered Implants

Implant design is one of the parameters for achieving successful primary stability. This study aims to examine the effect of a self-tapping blades implant design on initial stability in tapered implants. Polyurethane blocks of different densities were used to simulate different bone densities. The two different implant designs included one with self-tapping blades and one without self-tapping blades. Implants were placed at 3 different depths: apical third, middle third, and fully inserted at 3 different densities of polyurethane blocks. A resonance frequency (RF) analyzer was then used to measure stability of the implants. Repeated-measures analysis of variance was used to examine the effect of implant design, insertion depth, and block density on RF. Analysis of covariance was used to examine the strength of association between RF and the aforementioned factors. In both medium-density (P = .017) and high-density (P = .002) blocks, fully inserted non-self-tapping implants showed higher initial stability than self-tapping implants. No differences were noted between the 2 implant designs that were not fully inserted. The highest strength of association was with insertion depth (standardized beta [std β] = −0.60, P = .0001), followed by block density (std β = −0.15, P = .0002). Implant design showed a weak association (std β = −0.07, P = .09). In conclusion, fully inserted implants without self-tapping blades have higher initial stability than implants with self-tapping blades. However, the association strength between implant design and initial stability is less relevant than other factors, such as insertion depth and block density. Thus, if bone quality and quantity are optimal, they may compensate for design inadequacy.