Repair of Radial Fractures in Toy Breed Dogs with Self-Reinforced Biodegradable Bone Plates, Metal Screws, and Light-Weight External Coaptation

Load-bearing composite fracture-fixation devices with tailored fibre placement for toy-breed dogs

Fibre reinforced composites are attractive materials for hard tissue reconstructions, due to the high strength and low flexural modulus. However, lack of contourability in the operation theatre inhibits their clinical applications. The study presents a novel in situ contourable composite implant system for load-bearing conditions. The implant system consists of a thin bioresorbable shell with several cavities, much like bubble-wrap. The central cavity contains a semi-flexible glass fibre preform prepared using Tailored Fibre Placement method. The preform is either pre-impregnated with a light curable resin, or the resin is injected into the cavity during the surgical procedure, followed by light curing. The semi-flexible glass fibre preforms were also examined as separate devices, "miniplates". Two types of miniplates were scrutinized, a simplified pilot design and a spatially refined, "optimized" design. The optimized miniplates were implemented as biostable and bioresorbable versions. The feasibility of the in situ contourable composite implant system was demonstrated. The potential of Tailored Fibre Placement for the semi-flexible glass fibre preforms and miniplates was confirmed in a series of biomechanical tests. However, structural optimization is required. Antebrachial fractures in toy-breeds of dogs are exemplar veterinary applications of the devices; further applications in veterinary and human patients are foreseen.

Bacterial osteomyelitis in veterinary orthopaedics: Pathophysiology, clinical presentation and advances in treatment across multiple species

Bacterial osteomyelitis in veterinary patients can be challenging to diagnose and treat, given limited therapeutic options and reported success rates. Osteomyelitis is frequently associated with surgical implant devices, including those required to optimise stability and healing of fractures. However, management of osteomyelitis sometimes necessitates the removal of these surgical implant devices in order to eradicate infection or limit implant-related osteolysis. The goal of this article is to provide a general and species-specific review of bacterial osteomyelitis in a selection of domestic veterinary species, including cats, dogs, horses, cattle and camelids, with a focus on classification, clinical presentation, aetiologic agents, and common therapeutic interventions reported in the literature. New treatment options emerging from research and human medicine will be also discussed, as they also apply to current or future care of veterinary patients with osteomyelitis.

Biostable glass fibre-reinforced dimethacrylate-based composites as potential candidates for fracture fixation plates in toy-breed dogs: Mechanical testing and finite element analysis

In toy-breed dogs (bodyweight <5 kg), the fractures of the radius and ulna are particularly common and can be caused by minimal trauma. While fracture fixation using metallic plates is a feasible treatment modality, the excessive stiffness of these devices produces the underloading of the bone which may result in the adverse bone remodelling and complications in the healing of the fracture. In this study, we investigated bisphenol A glycidylmethacrylate -based glass fibre reinforced composites as potential alternatives to metals in the devices intended for the fracture fixation of the distal radius in toy-breed dogs. Four composites with different glass fibre reinforcements were prepared as rectangular specimens and as fracture fixation plates. These were mechanically tested in three-point and four-point bending. There were two controls: polyether etherketone reinforced with short carbon fibres (specimens and plates) and commercially available stainless-steel plates. Finite element simulations were used for the assessment of the behaviour of the plates. For the control stainless steel plate, the bending strength was 1.358 N*m, superior to that of any of the composite plates. The composite plate with the matrix reinforced with continuous unidirectional glass fibres had the bending strength of 1.081 N*m, which is sufficient in this clinical context. For the plates made of polyether etherketone reinforced with carbon fibres, the strength was 0.280 N*m. Similar conclusions on the biomechanical behaviour of the plates could be made solely based on the results of the finite element simulations, provided the geometries and the material properties are well defined.

Short-Term Prospective Clinical Evaluation of a Polyglycolic Acid Tibial Tuberosity Advancement Cage Implant

This study investigated the short-term radiographic healing of the osteotomy following tibial tuberosity advancement (TTA), maintenance of patellar tendon angle (PTA), and complications in dogs receiving a polyglycolic acid (PGA) TTA cage. Patients diagnosed with unilateral cranial cruciate ligament disease requiring a 9- or 12-mm TTA cage were included. Twenty-six consecutive client-owned dogs were prospectively selected for this clinical study. Age, weight, sex, breed, cage size, surgery date, and follow-up time were recorded. Radiographs were scored for healing and measured for PTA immediately, at 6 wk, and at 10 wk postoperatively. All stifles were assessed for complications throughout the study period. Stifles with PGA cages had similar overall healing scores compared to previously reported values for metallic cages, and the PTA was well maintained at 6 and 10 wk postoperatively. Polyglycolic acid cages were associated with a higher complication rate (10/26, 38%; 95% confidence interval, 0.19-0.61) compared with previously reported complication rates for metallic cages. Despite favorable healing scores and overall PTA maintenance, PGA cage use resulted in a high complication rate. Proposed advantages offered by this particular implant over currently used metallic cages are offset by this high complication rate. Additional investigation of bioabsorbable materials and implant design should be considered.

Augmentation of diaphyseal fractures of the radius and ulna in toy breed dogs using a free autogenous omental graft and bone plating

Objectives: Evaluation of the short-term outcome, duration of bone healing, and complications following bone plate fixation in dogs weighing [uni2264]6 kg, with and without the use of a free autogenous greater omental graft (OG).

Materials and methods: A retrospective clinical study reviewed the medical records of 25 dogs of body weight <6 kg with mid to distal diaphyseal fractures of the radius and ulna (29 fractures) treated with open reduction bone plate fixation. Thirteen out of 29 fractures were implanted with an additional 2–3 cm3 OG lateral, cranial, and medial to the fracture site, adjacent to the bone plate.

Results: Median time to radiographic healing in OG fractures (n = 11) was 70 days (range 28–98) compared to 106 days (range: 56–144) in non-OG grafted fractures (n = 14). The OG dogs had no major complications; minor complications included oedema, erythema, and mild osteopenia. Six of the eight non-OG dogs for which follow-up could be obtained developed osteopenia necessitating implant removal, four of which re-fractured the radius one to five months after implant removal, with one dog re-fracturing the limb a second time and resulting in amputation. Telephone follow-up of owners of OG dogs (n = 11) three to 15 months (median 10) post-surgery did not identify any signs of lameness or other complications. Owners of the non-OG dogs (n = 8) reported that there were not any signs of lameness six to 48 months (median 36) post-surgery.

Clinical relevance: Free autogenous omen-tal grafting of diaphyseal fractures of the radius and ulna was associated with radial and ulnar healing with minimal complications in dogs weighing less than 6 kg.

Treatment of fractures of the distal radius and ulna in toy breed dogs with circular external skeletal fixation: a retrospective study

Objective: To evaluate the effectiveness of circular external skeletal fixation (CESF) in treating fractures of the distal radius and ulna in toy breed dogs, and to document the type and frequency of complications associated with this technique.

Methods: The medical records of small breed dogs with fractures of the distal radius and ulna admitted to the University of Turin and to the Clinica Ferretti between 2002 and 2009 were retrospectively reviewed. The criteria for inclusion of cases in the study were: body weight of 5 kg or less, transverse or short oblique fracture of the distal third of the radius and ulna, no previous repair attempts, and treatment with CESF as the sole method of fixation.

Results: Twenty fractures in 16 dogs satisfied the criteria for inclusion into this study. No signs of infection or failure of fixation were detected in any case. Mean frontal plane alignment was 4.7° ± 2.7° and mean sagittal plane alignment was 12.7° ± 7.2°. Postoperative complications occurred in one patient. All fractures achieved union. Mean time until radiographic evidence of a bridging callus and subsequent implant removal was 71 days (range: 30–120).

Conclusions: The results of this study support the use of CESF for treatment of fractures of the distal radius and ulna in toy breed dogs as an alternative to other methods of fracture fixation. However, this technique requires a series of follow-up examinations to evaluate the stability of the apparatus, the soundness of the wires and to determine the appropriate time for implant removal.

A review of local antibiotic implants and applications to veterinary orthopaedic surgery

In the face of increasing incidence of multidrug resistant implant infections, local antibiotic modalities are receiving increased attention for both infection prophylaxis and treatment. Local antibiotic therapy that achieves very high antibiotic drug concentrations at the site of the implant may represent an avenue for treatment of biofilmforming bacterial pathogens. Randomized controlled trials in human patients have demonstrated an infection risk reduction when antibiotic-impregnated cement is used for infection prophylaxis in implanted joint prostheses, and when a gentamicin-impregnated collagen sponge is used for infection prophylaxis in midline sternotomy. The other modalities discussed have for the most part yet to be evaluated in randomized controlled trials in veterinary or human patients. In general, the in vivo pharmacokinetics and appropriate dosing profiles for local antibiotic modalities have yet to be elucidated. Toxicity is possible, and attention to the dose applied is warranted.

Prospective Randomized Clinical and Radiographic Evaluation of a Novel Bioabsorbable Biocomposite Tibial Tuberosity Advancement Cage Implant

OBJECTIVE

To evaluate the suitability of a novel bioabsorbable biocomposite cage (BC) implant for use in tibial tuberosity advancement (TTA) surgery in dogs with cranial cruciate ligament (CrCL) disease and to compare radiographic osteotomy healing scores and complications between groups that received either a BC or stainless steel cage (SSC).

STUDY DESIGN

Prospective randomized clinical study.

ANIMALS

Dogs with unilateral CrCL rupture (n=56).

METHODS

TTA was performed in 60 consecutive dogs using either a BC (30 dogs) or SSC (30 dogs). Patient parameters, 6 week and 6 month postoperative radiographic osteotomy healing scores, time elapsed to postoperative rechecks, and complications were compared between groups. Osteotomy healing was graded using a 5-point (0-4) scale. Data were analyzed using Wilcoxon Rank Sum tests and χ(2) tests with significance set at P<.05.

RESULTS

Fifty-six dogs (30 BC, 26 SSC) had complete medical and radiographic records at 6 months for inclusion in data analysis. Three complications occurred in the BC group (1 major, 2 minor) and 2 occurred in the SSC group (2 minor). There was no statistical difference in patient parameters, 6 week healing scores, or complications between BC and SSC groups. Healing scores at 6 months were significantly higher in the BC group (3.3 ± 0.52) compared to the SSC group (2.9 ± 0.69; P=.04).

CONCLUSION

Based on improved BC osteotomy healing scores 6 months after surgery with no significant differences in complications compared to SSC, BC TTA cages are a viable alternative to SSC.

Composites of poly(l-lactide-trimethylene carbonate-glycolide) and surface modified calcium carbonate whiskers as a potential bone substitute material

Calcium carbonate whiskers are surface modified by grafting of poly(l-lactide) chains, and used to reinforce a biodegradable terpolymer matrix. Optimal properties are obtained for composites with a PLLA-g-CCW content of 2 wt%.

Biomechanical fatigue analysis of an advanced new carbon fiber/flax/epoxy plate for bone fracture repair using conventional fatigue tests and thermography

The current study is part of an ongoing research program to develop an advanced new carbon fiber/flax/epoxy (CF/flax/epoxy) hybrid composite with a "sandwich structure" as a substitute for metallic materials for orthopedic long bone fracture plate applications. The purpose of this study was to assess the fatigue properties of this composite, since cyclic loading is one of the main types of loads carried by a femur fracture plate during normal daily activities. Conventional fatigue testing, thermographic analysis, and scanning electron microscopy (SEM) were used to analyze the damage progress that occurred during fatigue loading. Fatigue strength obtained using thermography analysis (51% of ultimate tensile strength) was confirmed using the conventional fatigue test (50-55% of ultimate tensile strength). The dynamic modulus (E(⁎)) was found to stay almost constant at 47GPa versus the number of cycles, which can be related to the contribution of both flax/epoxy and CF/epoxy laminae to the stiffness of the composite. SEM images showed solid bonding at the CF/epoxy and flax/epoxy laminae, with a crack density of only 0.48% for the plate loaded for 2 million cycles. The current composite plate showed much higher fatigue strength than the main loads experienced by a typical patient during cyclic activities; thus, it may be a potential candidate for bone fracture plate applications. Moreover, the fatigue strength from thermographic analysis was the same as that obtained by the conventional fatigue tests, thus demonstrating its potential use as an alternate tool to rapidly evaluate fatigue strength of composite biomaterials.

Comparative study of bone repair in mandibular body osteotomy between metallic and absorbable 2.0 mm internal fixation systems. Histological and histometric analysis in dogs: a pilot study

The objective of this study was to compare the bone repair along a mandibular body osteotomy stabilized with 2.0 mm absorbable and metallic systems. 12 male, adult mongrel dogs were divided into two groups (metallic and absorbable) and subjected to unilateral osteotomy between the mandibular third and fourth premolars, which was stabilized by applying two 4-hole plates. At 2 and 18 weeks, three dogs from each group were killed and the osteotomy sites were removed and divided equally into three parts: the upper part was labelled the tension third (TT), the lower part the compression third (CT), and the part between the TT and CT the intermediary third (IT). Regardless of the treatment system, union between the fragments was observed at 18 weeks and the CT showed more advanced stages of bone repair than the TT. Histometric analysis did not reveal any significant differences among the 3 parts or systems in the distance between bone fragments at 2 weeks. Although at 18 weeks the proportions of newly formed bone did not differ among TT, IT and CT, significantly enhanced bone formation was observed in all sections for the metallic group. The patterns of repair were distinct between treatments.

Avaliação mecânica da placa de compósito de poli-hidroxibutirato e hidroxiapatita em modelos ósseos de gato

Avaliou-se mecanicamente o compósito de poli-hidroxibutirato 70% e hidroxiapatita 30% na forma de placas para fixação óssea. Foram utilizadas 15 placas do compósito com 60mm de comprimento por 10mm de largura e espessura variando de 3mm no centro a 5mm nas extremidades, com seis orifícios. As placas foram fixadas em um modelo acrílico de fêmur de gato, e o conjunto foi submetido aos testes de flexão com quatro pontos, compressão axial e torção, empregando-se como referência microplacas de aço ASTM-F138 2,0mm. As médias das forças máximas nos testes de flexão e de compressão foram, respectivamente, de 323,20N e 617,70N, para as placas de compósito, e de 352,33N e 547,70N, para as placa de aço. No teste de torção, as médias dos torques máximos foram de 1,01Nm para as placas de compósito e de 1,15Nm para as placas de aço. Não houve diferença estatística entre as placas de compósito e de aço. O comportamento físico do material foi diferente, pois as placas de compósito se romperam e as de aço apenas se deformaram, revelando baixa ductilidade das placas de compósito

Emprego experimental da placa de compósito poli-hidroxibutirado/hidroxiapatita na fixação femoral em gatos

Avaliou-se o compósito de poli-hidroxibutirado (PHB) 70% e hidroxiapatita (HA) 30% na forma de placas para fixação óssea em gatos. Foram usadas placas do compósito com 60mm de comprimento por 10mm de largura e espessura variando de 3mm no centro a 5mm nas extremidades, com seis orifícios. A placa do compósito foi empregada na fixação de osteotomia de fêmur em quatro gatos, totalizando seis intervenções. Verificou-se a ruptura de cinco placas (83,3%) até o quarto dia e de uma placa (16,7%) aos 21 dias, quando se observou um calo ósseo exuberante. O resultado da implantação da placa no gato mostrou que o compósito não possui resistência suficiente para ser empregado como placas de fixação de fêmur em gatos.