Development of a New Model of Humeral Hemiarthroplasty in Rats.

PURPOSE: In vivo models are anatomically comparable to humans allowing to reproduce the patterns and progression of the disease and giving the opportunity to study the symptoms and responses to new treatments and materials. This study aimed to establish a valid and cost-effective in vivo rat model to assess the effects of implanted shoulder hemiarthroplasty materials on glenoid articular cartilage wear. METHODS: Eight adult male Wistar rats underwent right shoulder hemi-arthroplasty. A stainless steel metal bearing was used as a shoulder joint prosthesis. X-rays were performed one week after surgery to verify correct implant position. Additional X-rays were performed 30 and 60 days post-implantation. Animals were sacrificed 24 weeks after implantation. All specimens were evaluated with micro-CT for cartilage and bone wear characteristics as well as histologically for signs of osteoarthritis. Samples were compared to the non-operated shoulders. RESULTS: All animals recovered and resumed normal cage activity. All X-rays demonstrated correct implant positioning except for one in which the implant was displaced. Histologic evaluation demonstrated arthritic changes in the implanted shoulder. Decreased Trabecular thickness and Trabecular Spacing were documented among the implanted parties (p < .05). Bone Mineral Density and Tissue Mineral Density were reduced in the operated shoulder although not significantly (p = .07). CONCLUSIONS: This study demonstrated significant glenoid cartilage wearing in the operated shoulder. Furthermore, the presence of an intra-articular hemiarthroplasty implant diminished underlying glenoid bone quality. This novel, in vivo-model will enable researchers to test implant materials and their effects on cartilage and bone tissue in a cost-effective reproducible rat model.

Shoulder assessment by smartphone: a valid alternative for times of social distancing.

BACKGROUND: The delivery of orthopaedic care via telemedicine services has the potential to promote accessibility and decrease medical care expenses, while facilitating the control of infectious disease spreading. The purpose of this study was to assess agreement regarding diagnosis, recommended course of management and the perceived need for additional diagnostic testing between a video examination (VE) and a face to face (FTF) assessment of patients with shoulder disorders. METHODS: Forty-seven (18 females) patients presenting to a shoulder surgery clinic were assessed consecutively by VE and a FTF examination. All assessments were conducted by a shoulder specialist. Agreement regarding the established diagnosis, the recommended course of management and the need for additional diagnostic tests was assessed using percent agreement and kappa (95% CI) coefficient. Differences in the content, duration and satisfaction between the two examination modes were also assessed. RESULTS: Percent agreement and kappa (95% CI) coefficient for agreement regarding diagnosis were 85.1% and 0.82 (0.69-0.94), respectively. Percent agreement and kappa (95% CI) coefficient regarding the recommended course of management and the need for additional diagnostic testing were 61.7% and 0.43 (0.22-0.63), and 74.5% and 0.49 (0.25-0.74), respectively. The VE resulted in collection of less physical examination information, took longer to complete and was associated with less satisfaction by both patient and examiner. CONCLUSIONS: Video examination of patients with shoulder disorders may present a valid alternative to FTF examination. Nevertheless, the content of the video-based physical examination may need to be modified to facilitate a clearer detection of indications for specific interventions or diagnostic tests.

Modified Mesoporous Silica Nanoparticles with a Dual Synergetic Antibacterial Effect.

Application of mesoporous silica nanoparticles (MSNs) as antifouling/antibacterial carriers is limited and specifically with a dual synergetic effect. In the present work, MSNs modified with quaternary ammonium salts (QASs) and loaded with the biocide Parmetol S15 were synthesized as functional fillers for antifouling/antibacterial coatings. From the family of the MSNs, MCM-48 was selected as a carrier because of its cubic pore structure, high surface area, and high specific pore volume. The QASs used for the surface modification of MCM-48 were dimethyloctadecyl[3-(trimethoxysilyl)propyl]ammonium chloride and dimethyltetradecyl[3-(triethoxysilyl)propyl]ammonium chloride. The QAS-modified MCM-48 reveals strong covalent bonds between the QAS and the surface of the nanoparticles. The surface functionalization was confirmed by Fourier transform infrared spectroscopy, thermogravimetric analysis, elemental analysis, and ζ-potential measurements. Additional loading of the QAS-modified MCM-48 with a commercially available biocide (Parmetol S15) resulted in a synergetic dual antibacterial/antifouling effect. Either loaded or unloaded QAS-modified MSNs exhibited high antibacterial performance confirming their dual activity. The QAS-modified MCM-48 loaded with the biocide Parmetol S15 killed all exposed bacteria after 3 h of incubation and presented 100% reduction at the antibacterial tests against Gram-negative and Gram-positive bacteria. Furthermore, the QAS-modified MCM-48 without Parmetol S15 presented 77-89% reduction against the exposed Gram-negative bacteria and 78-94% reduction against the exposed Gram-positive bacteria. In addition, the modified MCM-48 was mixed with coating formulations, and its antifouling performance was assessed in a field test trial in northern Red Sea. All synthesized paints presented significant antifouling properties after 5 months of exposure in real seawater conditions, and the dual antifouling effect of the nanoparticles was confirmed.