Determining Which Combinatorial Combat-Relevant Factors Contribute to Heterotopic Ossification Formation in an Ovine Model.

Traumatic heterotopic ossification (HO) is frequently observed in Service Members following combat-related trauma. Estimates suggest that ~65% of wounded warriors who suffer limb loss or major extremity trauma will experience some type of HO formation. The development of HO delays rehabilitation and can prevent the use of a prosthetic.

Articular fragment restoration is critical to mitigate post-traumatic osteoarthritis in a porcine pilon fracture model.

Objective: During articular fracture reconstruction, orthopedic surgeons are frequently faced with the dilemma of retaining small articular fragments versus discarding these fragments. The purpose of this study was to compare post-traumatic osteoarthritis (PTOA) development between tibial plafond fractures and plafond fractures with a missing articular fragment (MF) in a porcine model.

Design: High-energy tibial plafond fractures in skeletally mature Yucatan mini pigs (n ​= ​12) were created.

Developing a combat-relevant translatable large animal model of heterotopic ossification.

Heterotopic ossification (HO) refers to ectopic bone formation, typically in residual limbs following trauma and injury. A review of injuries from Operation Iraqi Freedom (OIF) and Operation Enduring Freedom (OEF) indicated that approximately 70% of war wounds involved the musculoskeletal system, largely in part from the use of improvised explosive devices (IED) and rocket-propelled grenades (RPG). HO is reported to occur in approximately 63%-65% of wounded warriors from OIF and OEF.

Assessing the safety of an epiphyseal plate biopsy in a translational lamb model.

The literature demonstrates that obtaining a biopsy of the physis may be beneficial for diagnostic purposes. A small biopsy of the epiphyseal plate may allow for earlier detection of certain conditions and be used to monitor the healing of diseased and/or damaged physes. However, due to the fear of a growth arrest in a growing child, biopsies are not currently performed.

The effect of estrogen-like compound on rotator cuff tendon healing in a murine model.

Estrogen deficiency has been shown to negatively influence rotator cuff tendon healing. Therefore, the addition of an estrogen-like-compound (ELC) in a nonestrogen-deficient animal may improve the quality of a rotator cuff repair. The purpose of this study was to evaluate the effects of an ELC, diethylstilbestrol (DES), on tendon healing in a murine rotator cuff repair model.

Histological Analysis of a Retrieved Porous Tantalum Total Ankle Replacement: A Case Report.

Case: We present a case report documenting the retrieval and histological analysis of a porous tantalum (P-Ta) total ankle replacement (TAR) from a 50-year-old woman after a below-knee transtibial amputation. This rare opportunity to examine an intact TAR may help to better understand the implant-bone relationship because it would be in situ.

Conclusion: In this case study, we demonstrate bone ingrowth to the first layer of the P-Ta and organized trabecular orientation, suggesting that equal bone load was achieved on the base and the rails in both components using a transfibular surgical approach.

Bone ingrowth comparison of irregular titanium and cobalt-chromium coatings in a translational cancellous bone model.

The use of cobalt-chromium (CoCr)-bearing surfaces in total joint replacement (TJR) remains the predominate bearing surface. The conundrum with using this biomaterial has been selecting an ideal porous coating to assure reproducible skeletal attachment. There has been evidence that smooth CoCr beads may be inferior for skeletal attachment compared to identically shaped titanium (Ti) beads.

Assessing the effect of physeal biopsy on angular deformity in a rabbit model.

Obtaining a biopsy of the physis in a pediatric/juvenile could provide the ability to diagnose and manage children with physeal abnormalities. However, it has not yet been determined whether a physeal biopsy procedure affects angular deformity. We employed a rabbit model to collect biopsies of the distal femoral and proximal tibial physes on anesthetized, 8-week old New Zealand rabbits.

Plume height and surface coverage analysis of methicillin-resistant isolates grown in a CDC biofilm reactor.

Biofilm formation is a dynamic process that leads to mature communities over time. Despite a general knowledge of biofilm community formation and the resultant limitations of antibiotic therapy, there is a paucity of data describing specific plume heights, surface coverage and rates of maturation. Furthermore, little is published on the effect that the broth medium might have on the degree of biofilm maturation.

Growth substrate may influence biofilm susceptibility to antibiotics.

The CDC biofilm reactor is a robust culture system with high reproducibility in which biofilms can be grown for a wide variety of analyses. Multiple material types are available as growth substrates, yet data from biofilms grown on biologically relevant materials is scarce, particularly for antibiotic efficacy against differentially supported biofilms. In this study, CDC reactor holders were modified to allow growth of biofilms on collagen, a biologically relevant substrate.

System Setup to Deliver Air Impact Forces to a Sheep Limb: Preparation for Model Development of Blast-Related Heterotopic Ossification.

Background: Heterotopic ossification (HO) is a significant complication for wounded warriors with traumatic limb loss. Although this pathologic condition negatively impacts the general population, ectopic bone has been observed with higher frequency for service members injured in Iraq and Afghanistan due to blast injuries. Several factors, including a traumatic insult, bioburden, tourniquet and wound vacuum usage, and bone fractures or fragments have been associated with increased HO for service members.

In vivo analysis of a first-in-class tri-alkyl norspermidine-biaryl antibiotic in an active release coating to reduce the risk of implant-related infection.

Prosthetic joint infection (PJI) is a well-known and persisting problem. Active release coatings have promise to provide early protection to an implant by eradicating small colony biofilm contaminants or planktonic bacteria that can form biofilm. Traditional antibiotics can be limited as active release agents in that they have limited effect against biofilms and develop resistance at sub-lethal concentrations.

Ability of a wash regimen to remove biofilm from the exposed surface of materials used in osseointegrated implants.

The skin/implant interface of osseointegrated (OI) implants is susceptible to infection, causing excess pain, increased morbidity, and possibly implant removal. Novel distal femoral OI implants with binary nitride coatings have been developed with little physiological modeling to collect microbiological evidence of resistance to bacterial attachment. This in vitro study evaluated a Ti-6Al-4V alloy coated with TiNbN and treated with low plasticity burnishing (LPB) to assess attachment and biofilm formation of methicillin-resistant Staphylococcus aureus (MRSA) under physiologically modeling conditions compared to standard Ti-6Al-4V alloy materials with a polished ("Color Buff") or non-polished finish ("Satin Finish").

Flash autoclave settings may influence eradication but not presence of well-established biofilms on orthopaedic implant material.

Flash autoclaving is one of the most frequently utilized methods of sterilizing devices, implants or other materials. For a number of decades, it has been common practice for surgeons to remove implantable devices, flash autoclave and then reimplant them in a patient. Data have not yet indicated the potential for biofilms to survive or remain on the surface of orthopaedic-relevant materials following flash autoclave.

Effect of silver-loaded PMMA on Streptococcus mutans in a drip flow reactor.

Orthodontic retention has been proposed as a life-long commitment for patients who desire to maintain straight teeth. However, the presence of foreign material increases risk of bacterial colonization and caries formation, of which Streptococcus mutans is a key contributor. Multiple studies have assessed the ability of silver to be added to base plate material and resist attachment of S.

Transcortical or intracondylar? Which model is accurate for predicting biomaterial attachment in total joint replacement?

Despite four decades of research on material and porous coatings intended for cementless fixation in total joint replacement (TJR), aseptic mechanical loosening unrelated to particulate disease remains a concern. One main question asked is how translational are the animal models used to screen material and porous coatings intended for TJR fixation? Another question is how specific are the translational models at targeting the cementless TJR components that have the highest loosening rates? The hypothesis tested was that the bone response would be different between the two bone types-cortical and cancellous-used in translational animal modeling. The osteoblastic jumping distance (OJD), percent ingrowth, and appositional bone response were measured to assess the response between cancellous and cortical bone at two different anatomical locations, within the same limb.

The significance of calcified fibrocartilage on the cortical endplate of the translational sheep spine model.

To gain an understanding of the vertebral cortical endplate and factors that may affect the ability to achieve skeletal attachment to intervertebral implants and fusion, this study aimed to characterize the hypermineralized tissue on the cortical endplate of the vertebral body on a commonly used animal model. Skeletally mature sheep were injected with tetracycline prior to euthanasia and the C2-C3, T5-T6, and L2-L3 spinal motion segments were excised and prepared. Vertebral tissues were imaged using backscatter electron (BSE) imaging, histology, and tetracycline labeling was used to assess bone remodeling within different tissue layers.

In vivo efficacy of a silicone‒cationic steroid antimicrobial coating to prevent implant-related infection.

Active release antimicrobial coatings for medical devices have been developed to prevent and treat biofilm implant-related infections. To date, only a handful of coatings have been put into clinical use, with limited success. In this study, a novel antimicrobial compound was incorporated into a silicone (polydimethylsiloxane or PDMS) polymer to develop a novel active release coating that addressed several limitations of current device coatings.

Host bone response to polyetheretherketone versus porous tantalum implants for cervical spinal fusion in a goat model.

Study Design: In vivo assessment of polyetheretherketone (PEEK) and porous tantalum (TM) cervical interbody fusion devices in a goat model.

Objective: Directly compare host bone response to PEEK and TM devices used for cervical interbody fusion.

Summary Of Background Data: PEEK devices are widely used for anterior cervical discectomy and fusion but are nonporous and have limited surface area for bone attachment.