Tibial plateau fracture repairs augmented with calcium phosphate cement have higher in situ fatigue strength than those with autograft

Universal Hydrogel Carrier Enhances Bone Graft Success: Preclinical and Clinical Evaluation

Orthopedic, maxillofacial, and complex dentoalveolar bone grafting procedures that require donor-site bone harvesting can be associated with post-surgical complications. There has been widespread adoption of exogenously sourced particulate bone graft materials (BGM) for bone regenerative procedures; however, the particulate nature of these materials may lead to compromised healing outcomes, mainly attributed to structural collapse of the BGM, prolonged tissue healing. In this study, a fully synthetic thermoresponsive hydrogel-based universal carrier matrix (TX) that forms flowable and shapable putties with different BGMs while spatially preserving the particles in a 3D scaffold at the implantation site is introduced. The potential synergistic effect of the carrier is investigated in combination with particulate demineralized bone matrix (DBM) in a standard muscle pouch nude mice model (n = 24) as well as in a rabbit femoral critical-sized cortico-cancellous bone defect model (n = 9). Finally, the clinical usability, safety, and efficacy of the carrier for the delivery of deproteinized bovine bone mineral (DBBM) are evaluated in a controlled clinical trial for extraction socket alveolar ridge preservation (ARP) (n = 11 participants). Overall, the TX carrier improved the delivery of different types of BGMs, maintaining these spatially at the implantation site with minimal inflammatory responses, resulting in favorable bone regenerative outcomes.

Regional Gene Therapy for Bone Tissue Engineering: A Current Concepts Review

The management of segmental bone defects presents a complex reconstruction challenge for orthopedic surgeons. Current treatment options are limited by efficacy across the spectrum of injury, morbidity, and cost. Regional gene therapy is a promising tissue engineering strategy for bone repair, as it allows for local implantation of nucleic acids or genetically modified cells to direct specific protein expression. In cell-based gene therapy approaches, a variety of different cell types have been described including mesenchymal stem cells (MSCs) derived from multiple sources-bone marrow, adipose, skeletal muscle, and umbilical cord tissue, among others. MSCs, in particular, have been well studied, as they serve as a source of osteoprogenitor cells in addition to providing a vehicle for transgene delivery. Furthermore, MSCs possess immunomodulatory properties, which may support the development of an allogeneic "off-the-shelf" gene therapy product. Identifying an optimal cell type is paramount to the successful clinical translation of cell-based gene therapy approaches. Here, we review current strategies for the management of segmental bone loss in orthopedic surgery, including bone grafting, bone graft substitutes, and operative techniques. We also highlight regional gene therapy as a tissue engineering strategy for bone repair, with a focus on cell types and cell sources suitable for this application.

Better clinical outcomes and faster weight bearing after medial opening-wedge high tibial osteotomy using allogeneic than synthetic graft: A secondary analysis of a Francophone Arthroscopy Society Symposium

INTRODUCTION

Although an autogenous graft has the highest rate of bone union to fill the void created in medial opening wedge high tibial osteotomy (MOWHTO), it also has some disadvantages, such as prolonged surgical time, donor site pain and morbidity. Two possible candidates for ideal grafts to replace autogenous grafts are allogeneic and synthetic graft, which are free from donor site pain and morbidity. However, previous reports comparing the clinical results of allogeneic to synthetic graft have been limited and controversial. The purpose of this study is to compare radiological findings and clinical outcomes of using synthetic versus allogenic graft to fill the void created in MOWHTO.

HYPOTHESIS

The present clinical study hypothesized that allogenic graft to fill the void would allow the higher rate of bone union and better clinical outcomes.

MATERIAL AND METHODS

This study compared the clinical and radiological outcomes of 95 patients who received MOWHTO to fill the void with either synthetic or allogenic graft (44 in Syn group, 51 in Allo group). Preoperatively and postoperatively, all patients were clinically evaluated; Return to work, Tegner activity score, and the Western Ontario and Macmaster University scores were reported. Radiographically, osteoarthritis grade and pre- and postoperative parameters were reported, including Hip-knee-ankle angle, mechanical lateral distal femoral angle, medial proximal tibial angle, joint line convergence angle, proximal posterior tibial angle, and limb length discrepancy. Perioperative details and complications were also reported.

RESULTS

Mean follow-up (months) were 24.0±1.3 in Syn group and 26.8±1.2 in Allo group (p=0.13). The postoperative improvement of pain and global WOMAC scores in Allo group were significantly better than in Syn group (ΔPain of WOMAC: Syn group 27.8±4.4, Allo group 49.3±3.8, p value <0.001*) (ΔGlobal score of WOMAC: Syn group 16.7±3.2, Allo group 37.4±4.9, p value=0.002*). The risk of hinge fracture in Syn group was significantly higher than in Allo group (Hinge fracture by Takeuchi grade (0/1/2/3): Syn group 37/3/3/1, Allo group 43/8/0/0, p value=0.04*). The timing of full weight bearing in Allo group was significantly earlier than in Syn group (Weight Bearing (1=FWB, 2=PWB 3wk, 3=PWB 6wk): Syn group 2.7±0.1, Allo group 2.3±0.1, p value=0.01*).

DISCUSSION

The use of allogenic graft to fill the void in MOWHTO does not show superiority in bone union compared to synthetic graft, however it improves pain, function, decreases the risk of hinge fracture and allows faster weight bearing than synthetic graft.

LEVEL OF PROOF

III; Case-control study.

Efficacy of Cal-Cemex as bone substitute for tibial plateau fractures

BACKGROUND

Various factors influence treatment and outcomes in tibial plateau fractures. Bone defects are among them. Many materials have been proposed to address this problem: allograft, bone-cements and various bone substitutes (BSM). Cal-Cemex (β-tricalciophosphate and polymethylmethacrylate) is a new hybrid bi-component BSM. A retrospective multicenter study was conducted based on the clinical experience of three European Hospitals, to demonstrate its clinical effectiveness, versatility and safety.

MATERIALS AND METHODS

From December 2016 to March 2022, 45 displaced tibial plateau fractures were treated with internal fixation and augmentation using Cal-Cemex. The average age was 55.9 years. According to Schatzker classification, we included 13 type II, 24 type III, 3 type V and 4 type VI fractures. The postoperative follow-up (FU) consisted of clinical and radiological examinations at 6 and 12 weeks and 1 year after surgery. A CT scan was performed preoperatively and 1 year after surgery. Full weight bearing was permitted after less than 6 weeks. Clinical data were collected from patient charts, while functional data were evaluated using the Rasmussen knee function score, the KOOS score and the Hospital for Special Surgery knee rating score (HSS), to evaluate the range of motion, axis and functionality of the knee.

RESULTS

The average FU was 42.8 months. CT scans taken at 1 year demonstrated a good surface osteointegration without radiolucent lines or osteolysis with good evidence of interdigitation and even bone ingrowth. At 1-year FU, the mean Rasmussen score was 24.7, the mean KOOS score was 90.7 and the mean HSS was 89.9 and the average full weight-bearing period 34.9. No patients had hardware failure or fracture secondary displacement.

DISCUSSION

Cal-Cemex combines biological features and good mechanical performances. It guarantees biocompatibility and osteoconductivity, although it is not fully reabsorbable; β-tricalciophosphate component gives macro- and microporosity that allow fluids to penetrate inside the material, to stimulate bone ingrowth.

CONCLUSIONS

The study suggests that Cal-Cemex is an option for tibial plateau fractures, where augmentation and support are necessary for early full weight bearing. The absence of major complications, ease of application, the possibility to cut and perforate this material support its extensive use in bone augmentation for trauma cases.

Augmentation in fragility fractures, bone of contention: a systematic review

BACKGROUND

Osteoporosis is a complex multifactorial disease characterized by reduced bone mass and microarchitectural deterioration of bone tissue linked to an increase of fracture risk. Fragility fractures occur in osteoporotic subjects due to low-energy trauma. Osteoporotic patients are a challenge regarding the correct surgical planning, as it can include fixation augmentation techniques to reach a more stable anchorage of the implant, possibly lowering re-intervention rate and in-hospital stay.

METHODS

The PubMed database and the Google Scholar search engine were used to identify articles on all augmentation techniques and their association with fragility fractures until January 2022. In total, we selected 40 articles that included studies focusing on humerus, hip, spine, and tibia.

RESULTS

Literature review showed a quantity of materials that can be used for reconstruction of bone defects in fragility fractures in different anatomic locations, with good results over the stability and strength of the implant anchorage, when compared to non-augmented fractures.

CONCLUSION

Nowadays there are no recommendations and no consensus about the use of augmentation techniques in osteoporotic fractures. Our literature review points at implementing the use of bone augmentation techniques with a specific indication for elderly patients with comminuted fractures and poor bone quality.

Percutaneous-Reinforced Osteoplasty: A Review of Emerging Treatment Strategies for Bone Interventions

Percutaneous-reinforced osteoplasty is currently being investigated as a possible therapeutic procedure for fracture stabilization in high-risk patients, primarily in patients with bone metastases or osteoporosis. For these patients, a percutaneous approach, if structurally sound, can provide a viable method for treating bone fractures without the physiologic stress of anesthesia and open surgery. However, the low strength of fixation is a common limitation that requires further refinement in scaffold design and selection of materials, and may potentially benefit from tissue-engineering-based regenerative approaches. Scaffolds that have tissue regenerative properties and low inflammatory response promote rapid healing at the fracture site and are ideal for percutaneous applications. On the other hand, preclinical mechanical tests of fracture-repaired specimens provide key information on restoration strength and long-term stability and enable further design optimization. This review presents an overview of percutaneous-reinforced osteoplasty, emerging treatment strategies for bone repair, and basic concepts of in vitro mechanical characterization.

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.

Experimental Drillable Magnesium Phosphate Cement Is a Promising Alternative to Conventional Bone Cements

Clinically used mineral bone cements lack high strength values, absorbability and drillability. Therefore, magnesium phosphate cements have recently received increasing attention as they unify a high mechanical performance with presumed degradation in vivo. To obtain a drillable cement formulation, farringtonite (Mg₃(PO₄)₂) and magnesium oxide (MgO) were modified with the setting retardant phytic acid (C₆H₁₈O₂₄P₆). In a pre-testing series, 13 different compositions of magnesium phosphate cements were analyzed concentrating on the clinical demands for application. Of these 13 composites, two cement formulations with different phytic acid content (22.5 wt% and 25 wt%) were identified to meet clinical demands. Both formulations were evaluated in terms of setting time, injectability, compressive strength, screw pullout tests and biomechanical tests in a clinically relevant fracture model. The cements were used as bone filler of a metaphyseal bone defect alone, and in combination with screws drilled through the cement. Both formulations achieved a setting time of 5 min 30 s and an injectability of 100%. Compressive strength was shown to be ~12–13 MPa and the overall displacement of the reduced fracture was <2 mm with and without screws. Maximum load until reduced fracture failure was ~2600 N for the cements only and ~3800 N for the combination with screws. Two new compositions of magnesium phosphate cements revealed high strength in clinically relevant biomechanical test set-ups and add clinically desired characteristics to its strength such as injectability and drillability.

Treatment of tibial plateau fractures with a novel fenestrated screw system for delivery of bone graft substitute

PURPOSE

The purpose of this study was to describe the incidence of subsidence in patients with AO/OTA 41 (tibial plateau) fractures which were repaired with a novel fenestrated screw system to used to deliver CaPO4 bone substitute material to fill the subchondral void and support the articular reduction.

METHODS

Patients with unicondylar and bicondylar tibial plateau fractures were treated according to the usual technique of two surgeons. After fixation, the Zimmer Biomet N-Force Fixation System®, a fenestrated screw that allows for the injection of bone substitute was placed and used for injection of the proprietary calcium phosphate bone graft substitute into the subchondral void. For all included patients, demographic information, operative data, radiographs, and clinic notes were reviewed. Patients were considered to have articular subsidence if one or more of two observations were made when comparing post-operative to their most recent clinic radiographs: > 2 mm change in the distance between the screw and the lowest point of the tibial plateau, > 2 mm change in the distance between the screw and the most superior aspect of the plate. Data were analyzed to determine if there were any identifiable risk factors for complication, reoperation, or subsidence using logistic regression. Statistical significance was set at p < 0.05.

RESULTS

34 patients were included with an average follow-up of 32.03 ± 22.52 weeks. There were no overall differences between height relative to the medial plateau or the plate. Two patients (5.9%) had articular subsidence. Six patients (15.2%) underwent reoperation, two (6%) for manipulations under anaesthesia due to arthrofibrosis, and four (12%) due to infections. There were 6 (19%) total infections as 2 were superficial and required solely antibiotics. One patient had early failure.

CONCLUSION

Use of a novel fenestrated screw system for the delivery of CaPO4 BSM results in articular subsidence and complication rates similar to previously published values and appears to be a viable option for addressing subchondral defects in tibial plateau fractures.

LEVEL OF EVIDENCE

IV.

Management of Lower Extremity Fractures in the Elderly: A Focus on Post-Operative Rehabilitation

Fractures in the elderly population are increasing in incidence and represent a rising burden of disease. It is difficult for the elderly population to adhere to restricted weight bearing, and immobility poses significant risks and increased morbidity. Therefore, a primary goal of fracture management in the elderly population is early post-operative weight bearing. This review examines published literature regarding lower extremity fracture management in the elderly, with a focus on post-operative rehabilitation. While extensive literature supports early weight bearing after hip fractures in the elderly, further research is warranted to provide guidelines for management of other lower extremity fractures in this population.

Augmented Fixation for Fractures of the Appendicular Skeleton

Despite advances in technology such as locked plating, osteoporotic bone and bone defects remain challenging complications for orthopaedic surgeons. The concept of augmented fixation is useful in these settings. Augmented fixation can be described as improving construct strength and stability by enhancing the surrounding environment. By understanding and using the techniques of alternative fixation strategies, endosteal or medullary support, structural grafting, or the use of bone graft substitutes in combination with standard or integrated fixation, surgeons can improve the chances of success when treating difficult fractures. The purpose of this article is to introduce the reader to the concept of augmented fixation, review strategies for its application, and review applicable published results.

Calcium phosphate cement and locked plate augmentation of distal femoral defects: A biomechanical analysis

PURPOSE

Bone tumors are common in the distal femur and often treated with intralesional curettage. The optimal method of stabilization of large distal femoral defects after curettage remains unclear. The goal of this study is to compare stabilization techniques for large distal femoral defects.

METHODS

Large defects (60 cm³) were milled in the distal lateral metaphysis of 45 adult composite sawbone femurs. The defect was either (1) left untreated or reconstructed with (2) locked plate fixation, (3) calcium phosphate cement packing, or (4) locked plate fixation with calcium phosphate cement packing, or (5) polymethylmethacrylate packing. Each specimen then underwent axial and torsional stiffness testing followed by torsional loading to failure. The data were analyzed using ANOVA with Tukey-Kramer post-hoc analysis.

RESULTS

The calcium phosphate cement filled defect with a locked plate was the stiffest construct in axial and torsional loading as well as the strongest in torque to failure. However, this difference only reached significance with respect to all other groups in torque to failure testing. The calcium phosphate cement filled defect with a locked plate was significantly stiffer than three of the four other groups in both axial and torsional stiffness testing.

CONCLUSIONS

These results indicate that calcium phosphate cement, with or without the addition of locked plate fixation, may provide improved construct stability under time zero testing conditions. This result warrants further testing under cyclic loading condition and consideration for fixation of large femoral metaphyseal defects in future clincal trails.

Biomechanical Evaluation of Promising Different Bone Substitutes in a Clinically Relevant Test Set-Up

(1) Background: Bone substitutes are essential in orthopaedic surgery to fill up large bone defects. Thus, the aim of the study was to compare diverse bone fillers biomechanically to each other in a clinical-relevant test set-up and to detect differences in stability and handling for clinical use. (2) Methods: This study combined compressive strength tests and screw pullout-tests with dynamic tests of bone substitutes in a clinical-relevant biomechanical fracture model. Beyond well-established bone fillers (ChronOS^TM Inject and Graftys^® Quickset), two newly designed bone substitutes, a magnesium phosphate cement (MPC) and a drillable hydrogel reinforced calcium phosphate cement (CPC), were investigated. (3) Results: The drillable CPC revealed a comparable displacement of the fracture and maximum load to its commercial counterpart (Graftys^® Quickset) in the clinically relevant biomechanical model, even though compressive strength and screw pullout force were higher using Graftys^®. (4) Conclusions: The in-house-prepared cement allowed unproblematic drilling after replenishment without a negative influence on the stability. A new, promising bone substitute is the MPC, which showed the best overall results of all four cement types in the pure material tests (highest compressive strength and screw pullout force) as well as in the clinically relevant fracture model (lowest displacement and highest maximum load). The low viscosity enabled a very effective interdigitation to the spongiosa and a complete filling up of the defect, resulting in this demonstrated high stability. In conclusion, the two in-house-developed bone fillers revealed overall good results and are budding new developments for clinical use.

Autograft, Allograft, and Bone Graft Substitutes: Clinical Evidence and Indications for Use in the Setting of Orthopaedic Trauma Surgery

Bone grafts are the second most common tissue transplanted in the United States, and they are an essential treatment tool in the field of acute and reconstructive traumatic orthopaedic surgery. Available in cancellous, cortical, or bone marrow aspirate form, autogenous bone graft is regarded as the gold standard in the treatment of posttraumatic conditions such as fracture, delayed union, and nonunion. However, drawbacks including donor-site morbidity and limited quantity of graft available for harvest make autograft a less-than-ideal option for certain patient populations. Advancements in allograft and bone graft substitutes in the past decade have created viable alternatives that circumvent some of the weak points of autografts. Allograft is a favorable alternative for its convenience, abundance, and lack of procurement-related patient morbidity. Options include structural, particulate, and demineralized bone matrix form. Commonly used bone graft substitutes include calcium phosphate and calcium sulfate synthetics-these grafts provide their own benefits in structural support and availability. In addition, different growth factors including bone morphogenic proteins can augment the healing process of bony defects treated with grafts. Autograft, allograft, and bone graft substitutes all possess their own varying degrees of osteogenic, osteoconductive, and osteoinductive properties that make them better suited for different procedures. It is the purpose of this review to characterize these properties and present clinical evidence supporting their indications for use in the hopes of better elucidating treatment options for patients requiring bone grafting in an orthopaedic trauma setting.

Use of a biphasic cement bone substitute in the management of metaphyseal fractures

OBJECTIVES

In recent years, the increase in utilisation of bone substitutes in the reconstruction of bone defects has been fuelled by donor site complications associated with autologous bone harvesting. However the ability of bone substitute to stimulate bone union while maintaining fracture reduction has been a topic of debate. Cerament Bone Void Filler (CBVF) is a novel biphasic and injectable ceramic bone substitute that has high compressive strength and the ability to promote cancellous bone healing.

MATERIALS AND METHOD

This is a retrospective study to evaluate the surgical outcome of utilising CBVF in the treatment of depressed metaphyseal bone fractures over a two year period. The patients were followed up for at least six months after surgery and clinical parameters such as wound site complications were collated. Radiographic imaging was evaluated to determine loss of fracture reduction and rate of cement resorption.

RESULTS

Thirteen patients with depressed metaphyseal fractures were enrolled, which included: (i) one proximal humerus fracture; (ii) three tibial plateau fractures; and (iii) nine calcaneal fractures. None of the patients showed significant collapse in fracture reduction after six months of follow up. Cement resorption was noted in one patient as early as three weeks after surgery. There were no cases of cement leak or wound site complications.

CONCLUSION

Cerament Bone Void Filler (CBVF) is a promising bone graft substitute in the management of depressed metaphyseal bone fractures, with the ability to maintain fracture reduction despite cement resorption.

Split-Depressed Lateral Tibial Plateau Fractures: A Comparison of Augmented Percutaneous Screws Versus Augmented Plate and Screw Construct in a Cadaveric Model

OBJECTIVES

To compare the strength of fixation of percutaneous screw versus plate/screw fixation in a paired cadaver model of OTA 41-B3 (Schatzker type II) split-depression fractures of the lateral tibial plateau.

METHODS

Six matched pairs of cadaveric knees were acquired. An OTA 41-B3 (Schatzker type II) split-depression fracture was created in all specimens using a standardized method. One specimen from each matched pair of knees was fixed with percutaneous screws, and the other was fixed with a plate/screw construct. All specimens underwent augmentation of the central metaphyseal defect with calcium phosphate. Mean residual displacement (depression) was measured on thin-slice high-resolution computed tomography using a standardized methodology following 3 experimental conditions: (1) after they were fixed, before loading; (2) unloaded cycling (simulating postoperative range of motion exercises); and (3) loaded cycling (simulating postoperative weight-bearing). Load to failure was also compared.

RESULTS

After adjustment for baseline measurements, there was no significant difference in mean residual depression of the lateral tibial plateau between treatments groups after unloaded or loaded cyclic testing. Mean residual depression was less than 1 mm in both the treatment groups. Load to failure was statistically equivalent between treatment groups.

CONCLUSIONS

In our cadaveric study, in combination with calcium phosphate augmentation for both methods, percutaneous screw fixation conferred comparable strength of fixation compared with plate/screw constructs for treatment of OTA 41-B3 (Schatzker type II) tibial plateau fractures.

ß-TCP bone substitutes in tibial plateau depression fractures

BACKGROUND

The use of beta-tricalciumphospate (ß-TCP, Cerasorb®) ceramics as an alternative for autologous bone-grafting has been outlined previously, however with no study focusing on both clinical and histological outcomes of ß-TCP application in patients with multi-fragment tibial plateau fractures. The aim of this study was to analyze the long-term results of ß-TCP in patients with tibial plateau fractures.

METHODS

52 patients were included in this study. All patients underwent open surgery with ß-TCP block or granulate application. After a mean follow-up of 36months (14-64months), the patients were reviewed. Radiography and computed-tomography were performed, while the Rasmussen score was obtained for clinical outcome. Furthermore, seven patients underwent biopsy during hardware removal, which was subsequently analyzed by histology and backscattered electron microscopy (BSEM).

RESULTS

An excellent reduction with two millimeters or less of residual incongruity was achieved in 83% of the patients. At follow-up, no further changes occurred and no nonunions were observed. Functional outcome was good to excellent in 82%. Four patients underwent revision surgery due to reasons unrelated to the bone substitute material. Histologic analyses indicated that new bone was built around the ß-TCP-grafts, however a complete resorption of ß-TCP was not observed.

DISCUSSION

ß-TCP combined with internal fixation represents an effective and safe treatment of tibial plateau depression fractures with good functional recovery. While its osteoconductivity seems to be successful, the biological degradation and replacement of ß-TCP is less pronounced in humans than previous animal studies have indicated.

Percutaneous Repair of a Schatzker III Tibial Plateau Fracture Assisted by Arthroscopy

PURPOSE

Tibial plateau fractures are articular fractures that sometimes prove difficult to effectively manage and treat. Although fluoroscopy is frequently used to assess the articular reduction in the surgical repair of tibial plateau fractures, this video demonstrates the additional benefit of arthroscopy in assisting with the articular reconstruction of a Schatzker III tibial plateau fracture.

METHODS

The goal of operative treatment of tibial plateau is reconstruction of the articular surface followed by reestablishment of tibial alignment. Arthroscopy has been advocated as a possible supplement to the operative treatment of tibial plateau fractures. Arthroscopy-assisted fracture reduction has been shown to provide a significantly improved visualization of fracture fragment displacement when compared with traditional fluoroscopy use in select cases.

RESULTS

This video demonstrates the use of arthroscopy to visualize the articular surface and aid in reduction during fixation of a tibial plateau fracture. Initially, arthroscopic visualization confirms depression of lateral tibial plateau and the elevation of the fractured segment. After fixation with 2 partially threaded cancellous screws, arthroscopy confirms articular reduction and normal relation of lateral meniscus to the articular surface.

CONCLUSIONS

Arthroscopic visualization is a reliable technique for assessing articular reduction during surgical repair of a tibial plateau fracture. In addition, this technique enables the surgeon to assess for soft tissue injuries that could potentially go undiagnosed.

Bone Substitute Materials and Minimally Invasive Surgery: A Convergence of Fracture Treatment for Compromised Bone

This article focuses on the understanding of the biochemistry and surgical application of bone substitute materials (BSMs) and particularly the newer calcium phosphate materials that can form a structural orthobiologic matrix within the metaphyseal components of the periarticular bone. Six characteristics of BSMs are detailed that can be used as a guide for the proper selection and application of the optimal BSM type for periarticular fracture repair. These 6 characteristics of BSMs are divided into 2 pillars. One pillar details the 3 biochemical features of BSMs and the other pillar details the 3 surgical application properties.

Compressive fatigue properties of an acidic calcium phosphate cement-effect of phase composition

Calcium phosphate cements (CPCs) are synthetic bone grafting materials that can be used in fracture stabilization and to fill bone voids after, e.g., bone tumour excision. Currently there are several calcium phosphate-based formulations available, but their use is partly limited by a lack of knowledge of their mechanical properties, in particular their resistance to mechanical loading over longer periods of time. Furthermore, depending on, e.g., setting conditions, the end product of acidic CPCs may be mainly brushite or monetite, which have been found to behave differently under quasi-static loading. The objectives of this study were to evaluate the compressive fatigue properties of acidic CPCs, as well as the effect of phase composition on these properties. Hence, brushite cements stored for different lengths of time and with different amounts of monetite were investigated under quasi-static and dynamic compression. Both storage and brushite-to-monetite phase transformation was found to have a pronounced effect both on quasi-static compressive strength and fatigue performance of the cements, whereby a substantial phase transformation gave rise to a lower mechanical resistance. The brushite cements investigated in this study had the potential to survive 5 million cycles at a maximum compressive stress of 13 MPa. Given the limited amount of published data on fatigue properties of CPCs, this study provides an important insight into the compressive fatigue behaviour of such materials.

Calcium phosphate cement enhances the torsional strength and stiffness of high tibial osteotomies

PURPOSE

There has been a resurgence in the use of opening wedge high tibial osteotomy (owHTO). Calcium phosphate cement has been shown to improve strength in compression for augmentation of tibial plateau and owHTO fixation. However, knee kinematics includes a torsional load during ambulation, which is as yet unstudied in this model. The purpose of this paper is to investigate the effect of injectable calcium phosphate cement on the biomechanical stability of standard high tibial osteotomy defect with applied torsional load and ultimate stiffness of the supporting construct.

METHODS

Testing was performed on 22 bone mineral density-matched and age-matched cadaver specimens. Intact specimens were treated with 10° opening wedge osteotomies, identical surgical techniques as clinically used and fixation provided by iBalance© PEEK implant (Arthrex, Naples FL). Nine specimens were augmented with calcium phosphate injectable cement, Quickset (Arthrex Inc., Naples Fl). Constructs were for construct stiffness, torsional loads to failure, and mechanisms of failure. As a gold-standard comparison group, four samples were tested with a titanium, fixed angle device alone: Contourlock plate (Arthrex Inc., Naples Fl).

RESULTS

Peak torque to failure was significantly greater in samples augmented with calcium phosphate bone cement (23.0 ± 9.6 Nm) compared with specimens fixed with PEEK implant alone (18.1 ± 7.3). Construct stiffness in torsion was also significantly improved with bone cement application (349.0 ± 126.8 Nm/°) compared with PEEK implant alone (202.2 ± 153.4 Nm/°) and fixed angle implant system (142.9 ± 74.7 Nm/°).

CONCLUSION

Injectable calcium phosphate cement improves the initial maximal torsional strength and stiffness of high tibial osteotomy construct.

Reconstruction of the lateral tibia plateau fracture with a third triangular support screw: A biomechanical study

Background

Split fractures of the lateral tibia plateau in young patients with good bone quality are commonly treated using two minimally invasive percutaneous lag screws, followed by unloading of the knee joint. Improved stability could be achieved with the use of a third screw inserted either in the jail-technique fashion or with a triangular support screw configuration. The aim of this study was to investigate under cyclic loading the compliance and endurance of the triangular support fixation in comparison with the standard two lag-screw fixation and the jail technique.

Methods

Lateral split fractures of type AO/OTA 41-B1 were created on 21 synthetic tibiae and subsequently fixed with one of the following three techniques for seven specimens: standard fixation by inserting two partially threaded 6.5 mm cannulated lag screws parallel to each other and orthogonal to the fracture plane; triangular support fixation-standard fixation with one additional support screw at the distal end of the fracture at 30° proximal inclination; and jail fixation-standard fixation with one additional orthogonal support screw inserted in the medial nonfractured part of the bone. Mechanical testing was performed under progressively increasing cyclic compression loading. Fragment displacement was registered via triggered radiographic imaging.

Results

Mean construct compliance was 3.847 × 10^-3 mm/N [standard deviation (SD) 0.784] for standard fixation, 3.838 × 10^-3 mm/N (SD 0.242) for triangular fixation, and 3.563 × 10^-3 mm/N (SD 0.383) for jail fixation, with no significant differences between the groups (p = 0.525). The mean numbers of cycles to 2 mm fragment dislocation, defined as a failure criterion, were 12,384 (SD 2267) for standard fixation, 17,708 (SD 2193) for triangular fixation, and 14,629 (SD 5194) for jail fixation. Triangular fixation revealed significantly longer endurance than the standard one (p = 0.047).

Conclusion

Triangular support fixation enhanced interfragmentary stability at the ultimate stage of dynamic loading. However, the level of improvement seems to be limited and may not legitimate the intervention with an additional third screw.

Biomechanical analysis of different osteosyntheses and the combination with bone substitute in tibial head depression fractures

BACKGROUND

Tibial head depression fractures demand a high level of fracture stabilization to prevent a secondary loss of reduction after surgery. Elderly individuals are at an increased risk of developing these fractures, and biomechanical investigations of the fractures are rare. Therefore, the aim of this study was to systematically analyze different types of osteosyntheses in combination with two commonly used bone substitutes.

METHODS

Lateral tibial head depression fractures were created in synthetic bones. After reduction, the fractures were stabilized with eight different treatment options of osteosynthesis alone or in combination with a bone substitute. Two screws, 4 screws and a lateral buttress plate were investigated. As a bone substitute, two common clinically used calcium phosphate cements, Norian® Drillable and ChronOS™ Inject, were applied. Displacement of the articular fracture fragment (mm) during cyclic loading, stiffness (N/mm) and maximum load (N) in Load-to-Failure tests were measured.

RESULTS

The three different osteosyntheses (Group 1: 2 screws, group 2: 4 screws, group 3: plate) alone revealed a significantly higher displacement compared to the control group (Group 7: ChronOS™ Inject only) (Group 1, 7 [p < 0.01]; group 2, 7 [p = 0.04]; group 3, 7 [p < 0.01]). However, the osteosyntheses in combination with bone substitute exhibited no differences in displacement compared to the control group. The buttress plate demonstrated a higher normalized maximum load than the 2 and 4 screw osteosynthesis. Comparing the two different bone substitutes to each other, ChronOS™ inject had a significantly higher stiffness and lower displacement than Norian® Drillable.

CONCLUSIONS

The highest biomechanical stability under maximal loading was provided by a buttress plate osteosynthesis. A bone substitute, such as the biomechanically favorable ChronOS™ Inject, is essential to reduce the displacement under lower loading.

Development of a Three-Dimensional (3D) Printed Biodegradable Cage to Convert Morselized Corticocancellous Bone Chips into a Structured Cortical Bone Graft

This study aimed to develop a new biodegradable polymeric cage to convert corticocancellous bone chips into a structured strut graft for treating segmental bone defects. A total of 24 adult New Zealand white rabbits underwent a left femoral segmental bone defect creation. Twelve rabbits in group A underwent three-dimensional (3D) printed cage insertion, corticocancellous chips implantation, and Kirschner-wire (K-wire) fixation, while the other 12 rabbits in group B received bone chips implantation and K-wire fixation only. All rabbits received a one-week activity assessment and the initial image study at postoperative 1 week. The final image study was repeated at postoperative 12 or 24 weeks before the rabbit scarification procedure on schedule. After the animals were sacrificed, both femurs of all the rabbits were prepared for leg length ratios and 3-point bending tests. The rabbits in group A showed an increase of activities during the first week postoperatively and decreased anterior cortical disruptions in the postoperative image assessments. Additionally, higher leg length ratios and 3-point bending strengths demonstrated improved final bony ingrowths within the bone defects for rabbits in group A. In conclusion, through this bone graft converting technique, orthopedic surgeons can treat segmental bone defects by using bone chips but with imitate characters of structured cortical bone graft.

Mechanical behaviour of Bioactive Glass granules and morselized cancellous bone allograft in load bearing defects

Bioactive Glass (BAG) granules are osteoconductive and possess unique antibacterial properties for a synthetic biomaterial. To assess the applicability of BAG granules in load-bearing defects, the aim was to compare mechanical behaviour of graft layers consisting of BAG granules and morselized cancellous bone allograft in different volume mixtures under clinically relevant conditions. The graft layers were mechanically tested, using two mechanical testing modalities with simulated physiological loading conditions: highly controllable confined compression tests (CCT) and more clinically realistic in situ compression tests (ISCT) in cadaveric porcine bone defects. Graft layer impaction strain, residual strain, aggregate modulus, and creep strain were determined in CCT. Graft layer porosity was determined using micro computed tomography. The ISCT was used to determine graft layer subsidence in bone environment. ANOVA showed significant differences (p<0.001) between different graft layer compositions. True strains absolutely decreased for increasing BAG content: impaction strain -0.92 (allograft) to -0.39 (BAG), residual strain -0.12 to -0.01, and creep strain -0.09 to 0.00 respectively. Aggregate modulus increased with increasing BAG content from 116 to 653MPa. Porosity ranged from 66% (pure allograft) to 15% (pure BAG). Subsidence was highest for allograft, and remarkably low for a 1:1 BAG-allograft volume mixture. Both BAG granules and allograft morsels as stand-alone materials exhibit suboptimal mechanical behaviour for load-bearing purpose. BAG granules are difficult to handle and less porous, whereas allograft subsides and creeps. A 1:1 volume mixture of BAG and allograft is therefore proposed as the best graft material in load-bearing defects.

Bone Grafting: Sourcing, Timing, Strategies, and Alternatives

Acute fractures, nonunions, and nonunions with bone defects or osteomyelitis often need bone graft to facilitate union. There are several factors to consider when it is determined that a bone graft is needed. These factors include the source of the bone graft (autograft vs. allograft), proper timing for placement of the bone graft, strategies to avoid further complications (particularly in the setting of osteomyelitis), and with the development of a variety of bone graft substitutes, whether alternatives to autograft are available and appropriate for the task at hand. Autograft bone has commonly been referred to as the "gold standard" of bone grafts, against which the efficacy of other grafts has been measured. The best timing for when to place a bone graft or substitute is also somewhat controversial, particularly after an open fracture or a potentially contaminated bed. The treatment of infected nonunions, particularly those that require a graft to facilitate healing, can be quite challenging. Typically, the infection is completely eradicated before placement of a bone graft, but achieving a sterile bed and the timing of a bone graft require strategic thinking and planning. This review outlines the benefits of autografts, the most suitable sites for harvesting bone grafts, the timing of bone graft procedures, the potential risks and benefits of grafting in the face of infection, and the currently available bone graft extenders.

Arthroscopy Assisted Balloon Osteoplasty of a Tibia Plateau Depression Fracture: A Case Report

Context:

A clinical case of a tibia plateau fracture is presented which was treated with balloon osteoplasty and arthroscopy guidance. Balloon Tibioplasty has been shown to be a very useful method for the management of tibial plateau fractures. The use of calcium phosphate has been described in the literature for management and restoration of bone defects in tibial plateau fractures.

Case Report:

A 45-years-old Caucasian woman was presented after a fall from a ladder. The patient sustained a lateral tibia plateau fracture which was classified as Shatzker type III (AO 41-B2) with posterolateral depression of the joint surface. Surgical treatment was applied using a minimal approach which included percutaneous reduction of the fracture under arthroscopy and fluoroscopy guidance. The bone defect was filled with calcium phosphate via injection. The clinical outcome at the 6, 12 and 24 weeks was excellent with full-range of motion of the knee joint.

Conclusion:

Arthroscopy assisted balloon osteoplasty seems to be a safe and effective method for the treatment of depressed tibia plateau fractures. Further study is needed for the proper evidence based use and application of this method.

Effect of additional fixation in tibial plateau impression fractures treated with balloon reduction and cement augmentation

BACKGROUND

Isolated tibial plateau impression fractures can be reduced through minimally invasive techniques using balloon inflation and cement augmentation. No evidence exists yet if an additional fixation at all and which method of fixation is necessary in the treatment of these fractures. The purpose of this study was to compare a locking plate and a screw raft for additional fixation after balloon reduction and cement augmentation in isolated tibial plateau impression fractures. Loss of reduction was subsequently analysed without additional fixation.

METHODS

Lateral tibial plateau impression fractures were created in eight matched pairs of human cadaveric tibiae. Reduction was performed using a balloon inflation system, followed by cement augmentation. Additional fixation was performed with a lateral locking plate or a screw raft (four 3.5-mm screws). Specimens were cyclically loaded at 20-240N, 20-360N and 20-480N. Subsequently, additional fixation was removed and the last cyclic interval (20-480N) repeated. Loss of reduction was assessed by measuring subsidence of the subchondral bone.

FINDINGS

Fractures treated with plate fixation exhibited less subsidence at higher loads compared with those treated with screw raft fixation (P<0.05). Loss of reduction significantly increased after removal of the additional fixation.

INTERPRETATION

This experimental study suggests that loss of reduction can be minimised by using locking plate fixation after balloon reduction and cement augmentation in the treatment of isolated tibial plateau impression fractures.

Population-Based Epidemiology of Tibial Plateau Fractures

Although epidemiologic studies of tibial plateau fractures have been conducted, none have included geographically defined populations or a validated fracture classification based on computed tomography (CT). The goals of this study were to provide up-to-date information on the incidence and basic epidemiology of tibial plateau fractures in a large unselected patient population and to report the mechanisms of injury involved and the distribution of fractures according to a validated CT-based fracture classification. The authors conducted a population-based epidemiologic study of all patients treated for tibial plateau fracture over a 6-year period from 2005 to 2010. The study was based on an average background population of 576,364 citizens. A retrospective review of hospital records was performed. During this time, a total of 355 patients were treated for tibial plateau fracture. This group included 166 men and 189 women, and mean age was 52.6 years (SD, 18.3). The most common fracture type was AO type 41-B3, representing 35% of all tibial plateau fractures. The second most common fracture type was AO type 41-C3, representing 17% of all tibial plateau fractures. The incidence of tibial plateau fractures was 10.3 per 100,000 annually. Compared with women, men younger than 50 years had a higher incidence of fractures. The incidence of fractures increased markedly in women older than 50 years but decreased in men older than 50 years. In both sexes, the highest frequency was between the ages of 40 and 60 years.

Definitive fixation of tibial plateau fractures

Tibial plateau fractures present in a wide spectrum of injury severity and pattern, each requiring a different approach and strategy to achieve good clinical outcomes. Achieving those outcomes starts with a thorough evaluation and preoperative planning period, which leads to choosing the most appropriate surgical approach and fixation strategy. Through a case-based approach, this article presents the necessary pearls, techniques, and strategies to maximize outcomes and minimize complications for some of the more commonly presenting plateau fracture patterns.

Augmentation of tibial plateau fractures with an injectable bone substitute: CERAMENT™. Three year follow-up from a prospective study

BACKGROUND

Reduction of tibial plateau fractures and maintain a level of well aligned congruent joint is key to a satisfactory clinical outcome and is important for the return to pre-trauma level of activity. Stable internal fixation support early mobility and weight bearing. The augmentation with bone graft substitute is often required to support the fixation to mantain reduction. For these reasons there has been development of novel bone graft substitutes for trauma applications and in particular synthetic materials based on calcium phosphates and/or apatite combined with calcium sulfates. Injectable bone substitutes can optimize the filling of irregular bone defects. The purpose of this study was to assess the potential of a novel injectable bone substitute CERAMENT™|BONE VOID FILLER in supporting the initial reduction and preserving alignment of the joint surface until fracture healing.

METHODS

From June 2010 through May 2011 adult patients presenting with acute, closed and unstable tibial plateau fractures which required both grafting and internal fixation, were included in a prospective study with percutaneous or open reduction and internal fixation (ORIF) augmented with an injectable ceramic biphasic bone substitute CERAMENT™|BONE VOID FILLER (BONESUPPORT™, Lund, Sweden) to fill residual voids. Clinical follow up was performed at 1, 3, 9 and 12 months and any subsequent year; including radiographic analysis and Rasmussen system for knee functional grading.

RESULTS

Twenty four patients, balanced male-to-female, with a mean age of 47 years, were included and followed with an average of 44 months (range 41-52 months). Both Schatzker and Müller classifications were used and was type II or 41-B3 in 7 patients, type III or 41-B2 in 12 patients, type IV or 41-C1 in 2 patients and type VI or 41-C3 in 3 patients, respectively. The joint alignement was satisfactory and manteined within a range of 2 mm, with an average of 1.18 mm. The mean Rasmussen knee function score was 26.5, with 14 patients having an excellent result and the remaining 10 with a good result.

CONCLUSION

It can be concluded that radiological and clinical outcome was satisfactory and obtained in all cases without complications. This injectable novel biphasic hydroxyapatite and calcium sulfate ceramic material is a valuable armamentarium in the treatment of trauma where bone graft is required.

Impaction bone grafting has potential as an adjunct to the surgical stabilisation of osteoporotic tibial plateau fractures: Early results of a case series

INTRODUCTION

Osteoporotic tibial plateau fractures (TPFs) are difficult to treat with either open reduction internal fixation (ORIF) or acute total knee arthroplasty (TKA). They have high complication rates, poor outcomes and often fail in the short- to mid-term. We investigated the use of impaction bone grafting (IBG) as an adjunct to stabilise the fracture in a cohort of osteoporotic TPFs.

METHODS

Nine consecutive osteoporotic TPFs were surgically stabilised with ORIF augmented with IBG or with IBG alone (one pure depression fracture) using on average allograft from 2 femoral heads/case (range 1-4 heads or 25-100 cm(3)). The median bone mineral density T-score of the patients was -2.9 (-2.5 to -4.5). All patients were mobilised weight-bearing as tolerated immediately after surgery and had regular follow-up to a minimum of 2 years where functional scores were taken and gait was assessed. Fracture reduction was assessed on plain radiographs and computed tomography (CT) scans; maintenance of fracture reduction was monitored using plain radiographs, CT and radiostereometric analysis (RSA). Bone graft remodelling was assessed by comparison of immediate post-operative CT scans with scans at a minimum of 1 year.

RESULTS

All surgeries were uneventful. All patients progressed to full weight bearing within 6 weeks of surgery and regained a normal gait by 3 months. Seven fractures healed with a cranio-caudal migration of less than 3mm (range 0-2.6mm using RSA and 0-2mm using CT). Two fractures had an isolated posterolateral fragment depression of 13.5mm and 9 mm, respectively, which did not affect the overall joint alignment or clinical outcomes at short-term follow-up. At latest CT follow-up, on average 51% of the graft area (range 36-70%) had remodelled into new host bone.

CONCLUSION

Impaction bone grafting shows promising results as an adjunct to the surgical stabilisation of osteoporotic TPFs. In this case series the technique provided enough fracture stability for patients to mobilise weight-bearing as tolerated immediately after surgery and achieve full weight-bearing by the sixth postoperative week. There was no failure of fixation and 7 of the 9 cases healed with minimal fracture displacement.

Bone substitute first or screws first? A biomechanical comparison of two operative techniques for tibial-head depression fractures

BACKGROUND

The aim of this study was to investigate a drillable and injectable bone substitute (calcium phosphate cement) and the operative technique enabled by the drillable option in a new biomechanical fracture model for tibial depression fractures in synthetic bones.

MATERIALS AND METHODS

Lateral depression fractures of the tibial plateau (AO 41-B2, Schatzker III) were created in a biomechanical fracture model in three different synthetic bones (Sawbone 3401, Synbone 1110/1116). Reproducible fractures were generated employing Synbone 1110, which exhibited a comparable strength to human osteoporotic bones and was used for the further experiments. After reduction of the fractures, the stabilization was performed with two different operative techniques. In group 1, first an osteosynthesis with four screws was performed and then the metaphyseal defect was filled up with calcium phosphate cement (Norian drillable). In group 2, initially the filling up with Norian drillable was done enabling a complete filling of the defect, followed by placing of the screws. Displacement under cyclic loading with 250 N for 3,000 cycles, stiffness, and maximum load in load-to-failure tests were determined.

RESULTS

A comparison of the two operative techniques of stabilization showed a distinctly lower displacement and higher stiffness for group 2 when the defect was filled up first. For the maximum load, no significant differences could be demonstrated.

CONCLUSIONS

A complete filling of the defect by first applying the calcium phosphate cement significantly reduces the secondary loss of reduction of the depression fracture fragment under cyclic loading with a clinically relevant partial weight bearing. The beneficial effects of drillable calcium phosphate cement may also be transferable to defects other than tibial-head depression fractures.

Reduction and Stabilization of Depressed Articular Tibial Plateau Fractures: Comparison of Inflatable and Conventional Bone Tamps: Study of a Cadaver Model

BACKGROUND

Restoration of articular congruity and mechanical integrity of subchondral bone are important surgical goals of the treatment of intra-articular fractures. The purpose of this study was to compare the reduction quality and biomechanical integrity between cadaveric intra-articular tibial plateau fractures reduced with an inflatable bone tamp and contralateral fractures reduced with a series of cylindrical conventional metal bone tamps.

METHODS

A standardized lateral tibial plateau split-depression fracture was created in each leg of fourteen pairs of cadaver legs. In each pair, the fracture on one side was reduced under fluoroscopy with use of an inflatable bone tamp and the fracture on the contralateral, control side was reduced with conventional bone tamps and a mallet. Any residual bone defects were filled with calcium phosphate bone-void filler. The constructs were stabilized with a lateral tibial plateau buttress plate. Each articular reduction was qualitatively graded by blinded observers using fluoroscopic images, three-dimensional computed tomography (CT) scans, and visual inspection of the articular surface. Quantitative volumetric analysis was performed to calculate under-reduction, over-reduction, and total malreduction volumes. Each reduced fracture was cyclically loaded and then statically loaded to failure under axial compression, and the strength and stiffness of the constructs were compared between sides.

RESULTS

The majority (eleven) of the fourteen fractures reduced with the inflatable bone tamp were rated as having a better reduction than the contralateral fracture reduced with the conventional bone tamps. The median over-reduction and malreduction in the inflatable-tamp group (7% and 21.6%, respectively) were significantly less than those in the conventional-tamp group (19.2% and 47.1%), although the median under-reduction (6.2% in the inflatable-tamp group and 9.6% in the conventional-tamp group) did not differ significantly between groups. The fractures reduced with the inflatable tamp displaced less during cyclic loading than those reduced with the conventional tamp. Median static stiffness and yield load were also significantly higher in the inflatable-tamp group (880 N/mm and 704 N) than in the conventional-tamp group (717 N/mm and 641 N).

CONCLUSIONS

As compared with contralateral control fractures treated with conventional bone tamps, fractures treated with an inflatable bone tamp had qualitatively and quantitatively better reduction, typically resulting in a smoother articular surface with less residual defect volume. Fractures reduced with an inflatable bone tamp exhibited less subsidence during cyclic loading and greater stiffness under static loading compared with those treated with conventional bone tamps.

CLINICAL RELEVANCE

Using an inflatable bone tamp in association with calcium phosphate bone-void filler to reduce and maintain reduction of an articular fracture may help in achieving the surgical goal of a more anatomic reduction with better resistance to subsidence.

Fibular shaft allograft support of posterior joint depression in tibial plateau fractures

Posterior depression of the lateral articular surface of the tibial plateau can be difficult to elevate and support with morselized bone graft and internal fixation. Progressive collapse after open reduction and internal fixation has been described and can lead to failure in treatment. A standard anterolateral approach to the tibia may not allow direct reduction and stabilization of posterolateral joint depression given the anatomic barriers of the fibular collateral ligament and the proximal tibiofibular articulation. Posterolateral approaches to the tibial plateau have been described and may allow direct reduction of the articular depression. These approaches, however, require dissection close to the common peroneal nerve, and some approaches also require a proximal fibular osteotomy. The use of an intraosseous fibular shaft allograft as an adjunct to open reduction and internal fixation in select cases of depressed posterolateral tibial plateau fractures allows both reduction of the joint and stabilization of the articular segment through a single approach familiar to many orthopaedic surgeons.

Outcomes of Schatzker II tibial plateau fracture open reduction internal fixation using structural bone allograft

OBJECTIVES

The purpose of this study is to report the rate of anatomic reduction, articular subsidence, and clinical outcomes for Schatzker II tibial plateau fractures treated with structural bone allografts.

DESIGN

This is a retrospective case series.

SETTING

Academic Level I Trauma Center.

PATIENTS/PARTICIPANTS

A trauma registry was used to identify 77 Schatzker II tibial plateau fractures.

INTERVENTION

Schatzker II tibial plateau fracture open reduction internal fixation and structural bone graft using either Plexur P (N = 29) or fibular allograft (N = 48).

MAIN OUTCOME MEASUREMENT

The primary outcome was articular subsidence. Secondary outcomes included fracture malreduction and clinical outcomes including the Knee Outcome Survey Activities of Daily Living Scale, the Lower Extremity Functional Scale, and the Short Form (SF)-36.

RESULTS

No patients experienced subsidence > 2mm. This rate is significantly lower than published rates for autogenous iliac crest (30.3%, P < 0.0001) and calcium phosphate cement (8.7%, P = 0.0099). The rate of fracture malreduction was 11.7% (9/77); only 4 had more than 3 mm of residual incongruity. Average outcome scores were the following: Knee Outcome Survey Activities of Daily Living Scale, 81.7; Lower Extremity Functional Scale, 78.5; SF-36 physical component, 48.3; and SF-36 mental component, 53.1. There was no difference between patients treated with Plexur P or fibula with regard to the primary or secondary outcomes.

CONCLUSIONS

The use of structural allograft resulted in a high rate of anatomic reduction and negligible rate of articular subsidence and good clinical outcomes in the treatment of this population of Schatzker II tibial plateau fractures. This compares favorably with historical results using nonstructural grafts.

LEVEL OF EVIDENCE

Therapeutic level IV. See instructions for authors for a complete description of levels of evidence.

Effective combination of bone substitute and screws in the jail technique: a biomechanical study of tibial depression fractures

PURPOSE

The aim of this study was to investigate a new drillable calcium phosphate cement (Norian drillable Synthes GmbH) as a bone substitute either alone or in combination with screws in the jail technique (Petersen et al. Unfallchirurg Mar 109(3):219-234, 2006; Petersen et al. Unfallchirurg Mar 109(3):235-244, 2006) with regard to the primary stability in lateral tibial depression fractures.

METHODS

Lateral depression fractures of the tibial plateau were created in a biomechanical fracture model. After reduction they were stabilised with bone substitute (group one), bone substitute with additional four screws in the jail technique (group two) or four screws only (group three). Displacement under cyclic loading, stiffness and maximum load in load-to-failure tests were determined.

RESULTS

The groups with the bone substitute showed a lower displacement of the depressed articular fragment under cyclical loading and a higher stiffness. The maximum load was higher for the groups with screws.

CONCLUSIONS

Only the combination of bone substitute and screws prevented secondary loss of reduction and, at the same time, provided enough stability under maximum load.

Clinical assessment of calcium phosphate cement to treat tibial plateau fractures

The aim of this study was to examine histological changes in bone morphology after surgical treatment of tibial plateau fractures using calcium phosphate cement as a substitute for autologous bone grafting. A total of 42 patients with tibial plateau fractures were treated with open reduction, internal fixation, and calcium phosphate cement. A further 34 control patients underwent open reduction and internal fixation. Bone samples for histology were obtained during the surgery. Bone healing and functional recovery were assessed. Bone cell counts were significantly higher in samples obtained during the second surgery (81.2) compared with the first surgery (45.4, p < 0.001). Bone healing scores significantly increased with time after surgery ( p < 0.001). Mean Hospital for Special Surgery knee scores were rated “good” for both the calcium phosphate cement group (82.3) and control group (79.4) in 12 months, and were not significantly different between groups. Histological examination of samples obtained during the second surgery revealed well-arranged trabeculae, in addition to new bone and blood vessel formation. These histological, radiological, and functional findings suggest that calcium phosphate cement may be an effective substitute for autologous bone grafting to treat tibial plateau fractures.