Simulated subacromial injection instruction improves accuracy and skill level: a model for musculoskeletal procedural training.

BACKGROUND: Musculoskeletal (MSK) complaints often present initially to primary care physicians; however, physicians may lack appropriate instruction in MSK procedures. Diagnostic and therapeutic injections are useful orthopedic tools, but inaccuracy leads to unnecessary costs and inadequate treatment. The authors hypothesized that trainees afforded the opportunity to practice on a cadaver versus those receiving visual-aided instruction on subacromial injections (SAI) will demonstrate differences in accuracy and technique. METHODS: During Spring of the year 2022, 24 Internal Medicine and Family Medicine residents were randomly divided into control and intervention groups to participate in this interventional randomized cadaveric study. Each group received SAI instruction via lecture and video; the intervention group practiced on cadavers under mentored guidance. Subjects underwent a simulated patient encounter culminating in injection of latex dye into a cadaveric shoulder. Participants were evaluated based on a technique rubric, and accuracy of injections was assessed via cadaver dissection. RESULTS: Twenty-three of twenty-four participants had performed at least one MSK injection in practice, while only 2 (8.3%) of participants had performed more than 10 SAIs. There was no difference in technique between control 18.4 ± 3.65 and intervention 19.2 ± 2.33 (p = 0.54). Dissections revealed 3 (25.0%) of control versus 8 (66.7%) of intervention injections were within the subacromial space. Chi-Square Analysis revealed that the intervention affected the number of injections that were within the subacromial space, in the tissues bordering the subacromial space, and completely outside the subacromial space and bordering tissues (p = 0.03). The intervention group had higher self-confidence in their injection as opposed to controls (p = 0.04). Previous SAI experience did not affect accuracy (p = 0.76). CONCLUSIONS: Although primary care physicians and surgeons develop experience with MSK procedures in practice, this study demonstrates a role for early integrated instruction and simulation to improve accuracy and confidence. The goal of improving accuracy in MSK procedures amongst all primary care physicians may decrease costs and avoid unnecessary referrals, diagnostic tests, and earlier than desired surgical intervention.

Effects of Vancomycin/Tobramycin-Doped Ceramic Composite (Polyvinyl Alcohol Composite-Vancomycin/Tobramycin-Polymeric Dicalcium Phosphate Dihydrate) in a Rat Femur Model Implanted With Contaminated Porous Titanium Cylinders.

BACKGROUND: Periprosthetic joint infection (PJI) remains common and problematic. We hypothesized that using a bioceramic that provided rapid release of the antibiotics (vancomycin [VAN] or VAN and tobramycin [VAN and TOB]) from a polyvinyl-alcohol-composite (PVA) combined with a delayed and sustained antibiotic release from polymeric-dicalcium-phosphate-dihydrate (PDCPD) ceramic would inhibit S. aureus-associated implant infections. METHODS: A total of 50 male Sprague Dawley rats were randomly divided into 5 groups-I: negative control; II: bacteria only; III: bacteria + saline wash; IV: bacteria + PVA-VAN-PDCPD, and V: bacteria + PVA-VAN-TOB-PDCPD. A porous titanium (Ti) implant was press-fit into the rat knee. S. aureus-containing broth was added into the joint space creating a PJI. After 1 week, the joints from groups III to V were washed with saline and the fluid collected for bacterial quantification. This was followed by saline irrigation treatment (groups III to V) and application of the antibiotic-loaded PVA-PDCPD bioceramic (groups IV and V). On day 21, joint fluid was collected, and the implants harvested for bacterial quantification. RESULTS: No bacteria were isolated from the negative control (group I). The positive control (group II) was positive on both days 7 and 21. Bacteria were still present on day 21 in the fluid and implant in group III. Groups (IV and V) showed a decrease in the bacterial burden in the fluid and implant on day 21. There were significant differences in bacteria levels in the collected wash fluid and on the implant at day 21 between the saline wash (group III) and treatment groups (IV and V). CONCLUSIONS: In this animal model of acute periprosthetic infection, treatment with PVA-VAN-PDCPD and PVA-VAN/TOB-PDCPD reduced bacterial load in the infected joint and the infected Ti implant. Application of PVA-VAN-PDCPD and/or PVA-VAN/TOB-PDCPD after saline irrigation could be used as an addition to the treatment of PJI.

Directionally-Dependent Mechanical Properties of Ti6Al4V Manufactured by Electron Beam Melting (EBM) and Selective Laser Melting (SLM).

An investigation of mechanical properties of Ti6Al4V produced by additive manufacturing (AM) in the as-printed condition have been conducted and compared with wrought alloys. The AM samples were built by Selective Laser Melting (SLM) and Electron Beam Melting (EBM) in 0°, 45° and 90°-relative to horizontal direction. Similarly, the wrought samples were also cut and tested in the same directions relative to the plate rolling direction. The microstructures of the samples were significantly different on all samples. α' martensite was observed on the SLM, acicular α on EBM and combination of both on the wrought alloy. EBM samples had higher surface roughness (Ra) compared with both SLM and wrought alloy. SLM samples were comparatively harder than wrought alloy and EBM. Tensile strength of the wrought alloy was higher in all directions except for 45°, where SLM samples showed higher strength than both EBM and wrought alloy on that direction. The ductility of the wrought alloy was consistently higher than both SLM and EBM indicated by clear necking feature on the wrought alloy samples. Dimples were observed on all fracture surfaces.