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.

Shear force at failure and stiffness of all-inside meniscal repair devices.

The purpose of this study was to determine the failure load and stiffness of various meniscal repair devices. A total of 61 fresh-frozen porcine menisci (medial and lateral) were used for the study. A 30-mm vertical, full-thickness tear was created and repaired using one of three all-inside fixation devices and one inside-out repair in the vertical mattress pattern. We used the MaxBraid (Biomet, Warsaw, IN) inside-out suture as a control. The other devices tested were the Meniscal Cinch (Arthrex, Naples, FL), Ultra FasT-Fix (Smith & Nephew, Andover, MA), and the MaxFire MarXmen (Biomet, Warsaw, IN). In addition, two devices, MaxFire MarXmen and Ultra FasT-Fix, were tested using a horizontal mattress configuration. Using the vertical mattress pattern, the Meniscal Cinch had the highest average load to failure. The Meniscal Cinch was significantly less stiff than the other three devices (p < 0.04). For the MarXmen and Ultra FasT-Fix, no differences were noted for load to failure between horizontal and vertical mattress patterns. The mode of failure was significantly different when comparing the two different surgical techniques for the MaxFire MarXmen (p = 0.005). The MaxFire MarXmen device produced a significantly stiffer (p < 0.001) construct when following the manufacturer's instructions (5.8 N/mm) than with the technique used for the other all-inside devices (2.5 N/mm) The Meniscal Cinch had the highest load-to-failure value but the lowest stiffness of the group in the vertical mattress configuration. There was little difference in biomechanical properties between vertical and horizontal repair. Importantly, there was a significant difference in stiffness and failure mode for the MaxFire MarXmen when the manufacturer guidelines were not specifically followed.