Stresses and deformations of an osteosynthesis plate in a lateral tibia plateau fracture

This study has the aim to investigate the strain and stress in an anterolateral locking plate applied for the fixation of a lateral split fracture. To simulate a complex fracture situation, three segments were separated. With a FEM analysis, representative places for strain and stress measurement were determined. A locked osteosynthesis plate was instrumented with strain gauges and tested on a fractured and a non-fractured Saw Bone model. To simulate different loading situations, four different points of force application, from the center of the condyles to a 15 mm posterior position, were used with a medial-lateral load distribution of 60:40. The simulations as well as the biomechanical tests demonstrated that two deformations dominate the load on the plate: a bending into posterior direction and a bulging of the plate head. Shifting the point of application to the posterior direction resulted in increasing maximum stress, from 1.16 to 6.32 MPa (FEM analysis) and from 3.04 to 7.00 MPa (biomechanical study), respectively. Furthermore, the comparison of the non-fractured and fractured models showed an increase in maximum stress by the factor 2.06–2.2 (biomechanical investigation) and 1.5–3.3 (FEM analysis), respectively.

Comment to the Article by O.A. Kaplunov et al. “Hypotrophic Clavicle Pseudoarthrosis Treatment: A Case Report”

In the comment on the article Treatment of Hypotrophic Nonunion of the Clavicle: A Clinical Case, the reasons for the failure of primary and refixation of the clavicle closed fracture are analyzed in detail. A 70-year-old patient got a fracture of the middle third of the left clavicle diaphysis as a result of a fall. He underwent four surgical treatment options: plate osteosynthesis; plate osteosynthesis + bone autoplasty; plate osteosynthesis + vascularized fibular flap reconstruction; external osteosynthesis. A month after the fourth attempt of surgical treatment, fusion, improvement of the function of the right upper limb and the quality of life of the patient were achieved. Technological inaccuracy, namely, the lack of the fragments fixation stability due to the incorrectly chosen length of the plate, as well as an incomplete assessment of the anamnesis and the identified cognitive behavioral features of the patient, are considered as possible reasons for the treatment failure. The author of the comment highlights modern approaches to the treatment of clavicle fractures, and also briefly dwells on the theory of fracture fixation in general. He pays special attention to biological and mechanical factors affecting fractures healing. The author considers the compliance with the basic principles of osteosynthesis to be the main factor in achieving good results in fracture treatment.

Hypotrophic Clavicle Pseudoarthrosis Treatment: a Case Report

Background. The treatment of post-traumatic of the clavicle false joint remains a subject of discussion regarding the technology of the surgical intervention. Recently, the use of vascularized fibular flap reconstruction technique has been popularized, but the potential of the external osteosynthesis remains relevant. Clinical case description. A 70-year-old patient got a fracture of the middle third of the left clavicle diaphysis as a result of a fall. He underwent four surgical treatment options: plate osteosynthesis; plate osteosynthesis + bone autoplasty; plate osteosynthesis + vascularized fibular flap reconstruction; external osteosynthesis. A month after the fourth attempt of surgical treatment, fusion, improvement of the function of the right upper limb and the quality of life of the patient were achieved. Technological inaccuracy, namely, the lack of the fragments fixation stability due to the incorrectly chosen length of the plate, as well as an incomplete assessment of the anamnesis and the identified cognitive behavioral features of the patient, are considered as possible reasons for the treatment failure. Conclusion. Attempts of surgical treatment using plates in combination with bone autoplasty, including vascularized skin-bone flaps, do not always ensure the achievement of clavicle fractures fusion. In such situations, it is advisable to use the potential of external osteosynthesis with the reasonable planning.

Benefits and Biosafety of Use of 3D-Printing Technology for Titanium Biomedical Implants: A Pilot Study in the Rabbit Model

Background: Titanium has been used in osteosynthesis for decades and its compatibility and safety is unquestioned. Studies have shown that there is release and collection of titanium in the organ systems with little note of toxicity. The gold standard is considered to be titanium osteosynthesis plate produced by milling methods. The use of customized titanium plates produced with 3D printing, specifically direct metal laser sintering, have found increasing use in recent years. It is unknown how much titanium is released in these printed titanium implants, which is known to be potentially porous, depending on the heat settings of the printer. We hypothesize that the amount of titanium released in printed titanium implants may be potentially more or equal compared to the gold standard, which is the implant produced by milling. Methods: We studied the biosafety of this technology and its products by measuring serum and organ titanium levels after implantation of 3D-printed versus traditionally fabrication titanium plates and screws in a pilot study using the rabbit model. A total of nine rabbits were used, with three each in the control, milled and printed titanium group. The animals were euthanized after six months. Serum and organs of the reticuloendothelial system were harvested, digested and assayed for titanium levels. Results: Organ and serum titanium levels were significantly higher in rabbit subjects implanted with titanium implants (milled and printed) compared to the control group. However, there was no significant difference in organ and serum titanium levels of subjects implanted with milled and traditionally fabricated titanium implants. Conclusions: The biosafety of use of 3D-printed titanium implants and traditionally fabricated titanium implants are comparable. With this in mind, 3D-printed custom implants can not only replace, but will very possibly surpass traditionally fabricated titanium implants in the mode and extent of use.

Rational for Maxillofacial Fracture Plate Removal

Aim: To estimate indications and frequency of plate removal in patient treated for maxillofacial fractures. Method; In this retrospective study, records were reviewed from March 2015 to March 2018, over a period of 3 years. 139 Maxillofacial trauma patients treated with Open reduction and Internal Fixation with 202 plate, Result; In 139 patients, 202 plates were implanted for bone fractures. In total, 128(92%) were male and 11(8%) were female, 32(23.02%) had revisited with complaint and subsequently 47(23.26%) plates were removed. Mandible was commonest location where majority of the plates32(68.08%) were removed. Most common reason for plates removal was infection 20(42%). Minimum time for plate in situ was 3 months. Conclusion; the reason for plate removal is multifactorial. Establishing measures to minimize plate related complication and avoid patients from further invasive procedures. Keywords: Facial Bone Fracture, Osteosynthesis Plate, Plate Removal Trauma.

Selective Laser Melting of Patient Individualized Osteosynthesis Plates—Digital to Physical Process Chain

We report on the exemplified realization of a digital to physical process chain for a patient individualized osteosynthesis plate for the tarsal bone area. Anonymized patient-specific data of the right feet were captured by computer tomography, which were then digitally processed to generate a surface file format (standard tessellation language, STL) ready for additive manufacturing. Physical realization by selective laser melting in titanium using optimized parameter settings and post-processing by stress relief annealing results in a customized osteosynthesis plate with superior properties fulfilling medical demands. High fitting accuracy was demonstrated by applying the osteosynthesis plate to an equally good 3D printed bone model, which likewise was generated using the patient-specific computer tomography (CT) data employing selective laser sintering and polyamid 12. Proper fixation has been achieved without any further manipulation of the plate using standard screws, proving that based on CT data, individualized implants well adapted to the anatomical conditions can be accomplished without the need for additional steps, such as bending, cutting and shape trimming of precast bone plates during the surgical intervention. Beyond parameter optimization for selective laser melting, this exemplified digital to physical process chain highlights the potential of additive manufacturing for individualized osteosynthesis.

Current indications of mandibular condyle plate osteosynthesis: two cases reports

Introduction: Certain benign or malignant pathologies may require a mandibulectomy with resection of the condyle. The gold standard for this type of reconstruction is the microanastomosed fibular free flap. An immediate reconstruction technique using an osteosynthesis plate with condyle can be proposed. The aim of this article is to evaluate the indications and describe the complications of osteosynthesis plates with condyle, through the presentation of two clinical cases. Observation: Two patients were treated by radical hemi-mandibulectomy, with cervical curage, placement of an osteosynthesis plate with condyle, and coverage with flap of pectoralis major. Then they received radiation therapy with or without chemotherapy. No cases of erosion of the glenoid fossa or tympanal bone were found. Comments: Condyle osteosynthesis plates are an interesting alternative when a fibular flap cannot be performed for local (arteriopathy), carcinologic (poor prognosis), or general and anesthesic reasons. A tissue preservation protocol, with conformation and coverage of the plate must be undertaken to limit the risk of complications (infections, exposure and fracture of the plate, temporal bone erosion, heterotopic bone formations). Conclusion: Condyle osteosynthesis plates restore aesthetic and function immediately, temporarily or even permanently. Clinical and radiological follow-up must be established following this type of reconstruction.