How Prominent Are Gender Bias, Racial Bias, and Score Inflation in Orthopaedic Surgery Residency Recommendation Letters? A Systematic Review.

INTRODUCTION: Letters of recommendation are considered an important factor in the holistic ranking of orthopaedic residency applications. The standardized letter of recommendation (SLOR) was introduced in 2017 in response to the inherent bias and limited comparative value of traditional LORs. It includes standardized questions about an applicant's orthopaedic qualifications, designed to enable fair comparisons among candidates. However, disparate and inconsistent findings have made it difficult to draw meaningful conclusions from individual studies on the SLOR and narrative letter of recommendation. QUESTION/PURPOSES: In this systematic review we asked: (1) What is the distribution of applicant SLOR rating among nine domains and summative scores? (2) Are there applicant characteristics associated with SLOR ratings? (3) Is there gender and racial bias in the SLOR and narrative letter of recommendation? METHODS: PubMed, EBSCO, and Google Scholar electronic databases were queried on March 20, 2023, to identify all studies evaluating SLOR and narrative letter of recommendations between January 1, 2017, and March 20, 2023. Articles that evaluated orthopaedic SLOR or narrative LORs were included. Systematic reviews, case reports, duplicate studies between databases, and grey literature such as abstracts and articles on preprint servers were excluded. Eight studies including 6179 applicants and 18,987 letters of recommendation were included in the final analysis. The applicant classes ranged from years 2014 to 2020. Two reviewers independently evaluated the quality of the included studies using the Joanna Briggs Institute (JBI) tool for cross-sectional studies. The mean JBI score of included studies was 7.4 out of a maximum of 8, with higher scores indicating better quality. The primary outcome was to determine the distribution of applicant SLOR rankings in their summative score. Summative scores were separated into ranked to match, top one-third, middle one-third, lower one-third, and not a fit. Four studies reported the summative SLOR scores of applicants. Our secondary study goal was to assess applicant characteristics associated with SLOR summative scores and assess any bias present in the SLOR or narrative recommendation. Five studies compared SLOR ratings across applicant characteristics including gender, race, USMLE Step 1 score, USMLE Step 2 score, Alpha Omega Alpha (AΩA) membership, clerkship grades, and publications. Gender and racial bias were also assessed across five studies. Four studies utilized a linguistic analysis software to search letters of recommendation for differences in word category use by gender and race. RESULTS: Studies consistently found that a higher percentage of candidates were identified in the top percentile blocks than is mathematically possible. For example, the two studies that tallied the proportion of candidates ranking in the top 10% of applicants found that 36% and 42% were rated as being in the top 10%. Similarly, articles found more than 87% of applicants scored in the top one-third. Studies had mixed results, but in general, they suggested that AΩA status, higher Step 1 scores, and more research publications have a slightly positive association with increased SLOR scores. We found no evidence of gender bias against women, and in fact, most studies evaluating word choices found word choices for women candidates generally were stronger. Similarly, no consistent disparities were identified in word categories utilized in SLORs based on applicant race. CONCLUSION: Most notably, a mathematically impossible proportion of applicants were counted in the top percentiles in letters of recommendation. This compromises readers' abilities to differentiate candidates. Factors like AOA status and research publications displayed a modest positive correlation with SLOR scores. Gender bias against women or candidates from racial minority groups was not evident. CLINICAL RELEVANCE: We suggest that group SLOR authorship, with a consensus assessment by clerkship or residency directors, should be considered. We also recommend the incorporation of mean and SD scores for each letter writer (or group) alongside their letters. Furthermore, studies indicate that submitting all four SLOR letters can substantially improve an applicant's chances of success. We advise students to choose strategically and submit the maximum allowable number of SLORs.

Declining Inflation-Adjusted Medicare Physician Fees: An Unsustainable Trend in Hip Arthroscopy.

INTRODUCTION: Although hip arthroscopy continues to be one of the most used arthroscopic procedures, no focused, comprehensive evaluation of reimbursement trends has been conducted. The purpose of this study was to analyze the temporal Medicare reimbursement trends for hip arthroscopy procedures. METHODS: From 2011 to 2021, the Medicare Physician Fee Schedule Look-Up Tool was queried for Current Procedural Terminology (CPT) codes related to hip arthroscopy (29860 to 29863, 29914 to 29916). All monetary data were adjusted to 2021 US dollars. The compound annual growth rate and total percentage change were calculated. Mann-Kendall trend tests were used to evaluate the reimbursement trends. RESULTS: Based on the unadjusted values, a significant increase in physician fee was observed from 2011 to 2021 for CPT codes 29861 (removal of loose or foreign bodies; % change: 3.49, P = 0.03) and 29862 (chondroplasty, abrasion arthroplasty, labral resection; % change: 3.19, P = 0.03). The remaining CPT codes experienced no notable changes in reimbursement based on the unadjusted values. After adjusting for inflation, all seven of the hip arthroscopy CPT codes were observed to experience a notable decline in Medicare reimbursement. Hip arthroscopy with acetabuloplasty (CPT: 29915) and labral repair (CPT: 29916) exhibited the greatest reduction in reimbursement with a decrease in physician fee of 24.69% ( P < 0.001) and 24.64% ( P < 0.001), respectively, over the study period. DISCUSSION: Medicare reimbursement for all seven of the commonly used hip arthroscopy services did not keep up with inflation, demonstrating marked reductions from 2011 to 2021. Specifically, the inflation-adjusted reimbursements decreased between 19.23% and 24.69% between 2011 and 2021.

Demographics and Outcomes of Glenohumeral Dislocations in Individuals With Elevated Body Mass Index.

INTRODUCTION: No specific study has investigated the characteristics and outcomes of anterior shoulder dislocations in morbidly obese individuals. The purpose of this study was to describe shoulder dislocations in patients with body mass index (BMI) greater than 40. METHODS: A retrospective review was conducted to identify patients aged 18 years and older with a BMI ≥40 who presented with a shoulder dislocation in a single institution from 2000 to 2020. Dislocation patterns, associated injuries, treatment modalities, and associated complications were recorded. RESULTS: A significant increase was noted in the number of patients with BMI greater than 40 presenting per year (r2 = -0.831, P < 0.01) over the past 20 years. A significant increase was noted in the average BMI per year in this population (r2 = 0.504, P = 0.028). Fifteen patients (19.5%) experienced at least one recurrent dislocation episode. Ten patients had a Bankart lesion that was associated with an elevated BMI (P = 0.04). Nine patients (11.7%) sustained an associated neurologic injury (no association with BMI). CONCLUSIONS: Over time, there has been an increase in shoulder dislocations in morbidly obese individuals in the United States, alongside an overall increase in the average BMI of patients who present with shoulder dislocations.

Immediate plate fixation of open tibial plafond fractures does not elevate risk of infection.

OBJECTIVE: To determine if immediate plate fixation of open tibial plafond fractures has a negative effect on soft tissue complications and increases the risk of deep infection. DESIGN: This was a single-institution retrospective cohort study performed at level-1 trauma center. All patients with open OTA/AO 43C plafond fractures treated over 20-year period with follow-up until fracture union or development of deep infection. Ninety-nine of 333 identified patents met the inclusion criteria. The intervention was operative treatment of open tibial plafond fractures. The main outcome measurements were return to operating room for deep infection, nonunion, and below knee amputation. RESULTS: The overall rate of complications was 52%. Gender, body mass index, tobacco use, diabetes, ASA classification, time to OR from injury, wound location, and associated fibula fracture were not associated with deep infection. There was a significant difference in Gustilo-Anderson fracture grade among infected versus non-infected (P = 0.04). There was no significant difference in postoperative infection rates between patients treated with external fixation, external fixation and limited plate fixation, and plate fixation alone during initial surgery (P = 0.64). CONCLUSION: It is well established that open pilon fractures have a high incidence for postoperative infection and development of complications such as nonunion. As these injuries have poor clinical outcomes, any additional measures to prevent infection and soft tissue complications should be utilized. In appropriately selected cases, both immediate plate fixation and immediate limited plate fixation with external fixation at the time of I&D do not appear to elevate risk of deep infection. LEVEL OF EVIDENCE: Therapeutic Level III.

Common characteristics of shoulder injury related to vaccine administration following COVID-19 vaccination: a comprehensive systematic review.

BACKGROUND: The pathogenesis of shoulder injury related to vaccine administration (SIRVA) is incompletely understood, but it is postulated to be an immune-mediated inflammatory response to a vaccine antigen, leading to shoulder pain and dysfunction. The purpose of this investigation is to systematically review the literature related to SIRVA specifically after the COVID-19 vaccination by describing the diagnostic and clinical characteristics, diagnoses associated with SIRVA, and incidence between vaccine types. METHODS: A systematic review was performed to identify level I to IV studies and case descriptions of shoulder pain occurring after COVID-19 vaccination. To confirm that no studies were missing from the systematic review, references of studies from the initial search were scanned for additional relevant studies. RESULTS: A total of 22 studies, comprised of 81 patients, were identified meeting the inclusion/exclusion criteria. Reports were most commonly published from countries in Asia (53.1%; n = 43/81). The most commonly described vaccines were Oxford-AstraZeneca at 37.0% (n = 30/81) and Pfizer-BioNTech at 33.3% (n = 27/81). Symptoms occurred most commonly after at least 72 hours of administration (30.9%, n = 25/81). One hundred percent of patients (n = 81/81) described pain as an associated symptom and 90.1% of patients (n = 73/81) described multiple symptoms. The diagnostic modalities utilized to identify a specific pathology consisted of magnetic resonance imaging (55.6%; n = 45/81), ultrasound (28.4; n = 23/81), radiograph (25.9%; n = 21/81), and computed tomography (4.9%; 4/81). Nearly a third of patients (32.1%; n = 26/81) were diagnosed with bursitis, while 22 (27.2%) were diagnosed with adhesive capsulitis, 17 (21.0%) with either rotator cuff tear or tendinopathy, and 14 (17.3%) with polymyalgia rheumatica or polymyalgia rheumatica-like syndrome. The 2 most common treatment options were physical therapy (34.6%; n = 28/81) and nonsteroidal anti-inflammatory medications (33.3%; 27/81). The majority of SIRVA cases (52.1%; n = 38/73) completely resolved within a few weeks to months. CONCLUSION: Despite the limited quality and lack of large-scale studies, it is important for providers to recognize SIRVA as a potential risk factor as the number of patients receiving COVID-19 vaccinations and boosters continues to rise.

Effects of Opioid-Limiting Legislation and Increased Provider Awareness on Postoperative Opioid Use and Complications After Hip Arthroscopy.

Background: On August 31, 2017, Ohio passed legislation that regulates how opioids can be prescribed postoperatively. Studies have shown that such legislation is successful in reducing the morphine milligram equivalents (MMEs) prescribed after certain orthopaedic procedures. Purpose: (1) To determine if the opioid prescription-limiting legislation in Ohio reduced the cumulative MMEs prescribed after hip arthroscopy without significantly affecting the rates of emergency department (ED) visits, hospital readmissions, and reoperations within 90 days postoperatively, and (2) to assess risk factors associated with increased postoperative opioid dosing. Study Design: Cohort study; Level of evidence, 3. Methods: This study included patients who underwent primary and revision hip arthroscopy at a single institution over a 4-year period. The prelegislation (PRE) and postlegislation (POST) groups were defined as patients who underwent surgery before August 31, 2017, and on/after this date, respectively. The Ohio Automated Rx Reporting System was queried for controlled-substance prescriptions from 30 days preoperatively to 90 days postoperatively, and patient medical records were reviewed to collect demographic, medical, surgical, and readmission data. Inverse probability weighting-adjusted mean treatment effect regression models were used to measure the difference in mean outcomes between the PRE and POST cohorts. Results: A total of 546 patients (228 PRE, 318 POST) were identified. There was a 25% reduction in the cumulative MMEs prescribed to the POST group as compared with the PRE group during the first 90 days postoperatively (840 vs 1125 MME, respectively; P < .01). The legislation was associated with a significant decrease in the cumulative MMEs prescribed in the first 90 postoperative days (mean treatment effect = -280.6; P < .01), and there were no significant between-group differences in the frequency of ED encounters (8.8% PRE, 11.6% POST; P = .32), hospital readmissions (1.3% PRE, 0.9% POST; P = .70), or reoperations (0.9% PRE, 0.6% POST; P ≥ .99) during this period. Preoperative opioid use was a significant independent risk factor for increased cumulative MMEs in the first 90 days postoperatively (ß = 275; P < .01). Conclusion: Opioid prescription-limiting legislation in Ohio was associated with significant reductions in opioid MMEs dosing in the 90-day period following hip arthroscopy. This legislation had no significant effect on ED utilization, hospital readmissions, or reoperations within the same period. Preoperative opioid use was a significant risk factor for increased MME dosing after hip arthroscopy.

Total Ankle Arthroplasty for Posttraumatic Fracture Versus Primary Osteoarthritis: An Analysis of Complications, Revisions, and Prosthesis Survival.

BACKGROUND: Most outcome studies of total ankle arthroplasty (TAA) do not discriminate by arthritis etiology. The primary purpose of this study was to compare the complications of TAA between posttraumatic fracture osteoarthritis (fracture PTOA) and primary osteoarthritis (POA). METHODS: Ninety-nine patients who underwent TAA were retrospectively evaluated with a mean follow-up of 3.2 years (range 2 to 7.6 years). 44 patients (44%) had a diagnosis of POA while 55 patients (56%) had a diagnosis of fracture PTOA (40 malleolar fractures [73%], 14 pilon fractures[26%], and 1 talar fracture [1%]). Patient demographics, preoperative coronal plane alignment, postoperative complications, and revision surgery data were collected. Categorical variables were compared with chi square and Fisher exact tests and means with the Student t -test. Survival was assessed with Kaplan-Meier and log-rank analyses. RESULTS: A higher overall complication rate was associated with fracture PTOA (53%) compared with POA (30%) ( P = 0.04). No difference was observed in rates of any specific complication by etiology. Survival, defined as revision surgery with TAA prosthesis retention, was comparable between POA (91%) and fracture PTOA (87%) ( P = 0.54). When defined as failure requiring prosthesis explant, POA demonstrated significantly greater survival (100%) as compared with fracture PTOA (89%) ( P = 0.03). A higher rate of talar implant subsidence and loosening was noted in TAA with prior pilon (29%) as compared to malleolar fractures (8%) that was not statistically significant ( P = 0.07). Fracture PTOA was associated with preoperative valgus deformity ( P = 0.04). Compared with varus and normal alignment, preoperative valgus deformity was associated with the need for any revision surgery ( P = 0.01) and prosthesis explant ( P = 0.02). CONCLUSIONS: Compared with POA, fracture PTOA was associated with a markedly higher complication rate after TAA and was at higher risk of failure requiring prosthesis explant. Fracture PTOA was markedly associated with preoperative valgus malalignment, an identified risk factor in this series for revision surgery and prosthesis explant. Pilon fractures may represent a group at risk of complications related to talar implant subsidence and loosening compared with malleolar fractures and thus warrants additional investigation. LEVEL OF EVIDENCE: III.

Smaller diameter femoral tunnel biocomposite interference screws provide adequate fixation strength in anterior cruciate ligament reconstruction.

PURPOSE: The purpose of this study was to evaluate the effect of bioabsorbable interference screw diameter on the pullout strength and failure mode for femoral tunnel fixation in primary anterior cruciate ligament reconstruction (ACLR) at time zero fixation using bone-patellar tendon-bone (BTB) autograft in a cadaveric model. METHODS: Twenty-four fresh-frozen cadaveric knees were obtained from 17 different donors. Specimens were allocated to three different treatment groups (n = 8 per group) based on interference screw diameter: 6 mm, 7 mm, or 8 mm biocomposite interference screw. All specimens underwent dual energy X-ray absorptiometry (DEXA) scanning prior to allocation to ensure no difference in bone mineral density among groups (n.s.). All specimens underwent femoral-sided ACLR with BTB autograft. Specimens subsequently underwent mechanical testing under monotonic loading conditions to failure. The load to failure and failure mechanism were recorded. RESULTS: The mean pullout force (N) at time zero for each group was 309 ± 213 N, 518 ± 313 N, and 541 ± 267 N for 6 mm, 7 mm, and 8 mm biocomposite interference screw diameter, respectively (n.s.). One specimen in the 6 mm group, two specimens in the 7 mm group, and one specimen in the 8 mm group failed by screw pullout. The remainder in each group failed by graft failure (n.s.). CONCLUSION: Biocomposite interference screw diameter did not have a significant influence on fixation pullout strength or failure mode following femoral tunnel fixation using BTB autograft at time zero. A 6 mm interference screw can improve preservation of native bone stock, increase potential for biologic healing, and decrease the risk of damage to the graft during insertion without significantly compromising fixation strength. This study supports the use of smaller 6 mm interference screw diameter options for femoral tunnel fixation in ACLR.

The safe zones for endoscopic proximal hamstring repair: a cadaveric assessment of standard portal placement and their relationship to major neurovascular structures.

PURPOSE: To define the anatomical relationship of the major neurovascular structures to the standard endoscopic portals used in endoscopic hamstring repair. A secondary outcome was to determine the safest angle of insertion from each standard portal. METHODS: Endoscopic portals were established in the 3 standard locations (lateral, medial, and inferior) and Steinmann pins inserted at various angles. Each hip was dissected and the distance between the pins and the pertinent anatomy measured. RESULTS: The lateral portal placed the sciatic and posterior femoral cutaneous (PFC) nerves at greatest risk: direct injury to the sciatic nerve was seen in 11/30 (37%) of the lateral portals sited. A lateral portal with an approach at 60° was the most dangerous orientation with a mean distance of 0.36 ± 0.49 mm and 4.30 ± 2.69 mm from the sciatic and PFC nerves, respectively (p < 0.001). The 60° medial portal was the safest of all portals measured, at a mean distance of 67.37 ± 11.06mm (range, 47-78 mm) from the sciatic nerve and 58.90 ± 10.57 mm (range 40-70 mm) from the PFC nerve. CONCLUSIONS: While currently described techniques recommend establishing the standard lateral portal first, this study shows that it carries the highest risk of injury if used blind. We recommend that the standard medial endoscopic portal is established first to identify the neurovascular structures and minimise iatrogenic neurovascular injury. The inferior and lateral portals can then be established created under direct vision. The lateral portal should be inserted in a more horizontal orientation to decrease the risk of nerve injury.

Mesenchymal Stem Cell Delivery via Topographically Tenoinductive Collagen Biotextile Enhances Regeneration of Segmental Tendon Defects.

BACKGROUND: Successful management of massive rotator cuff (RC) tendon tears represents a treatment challenge because of the limited intrinsic healing capacity of native tendons and the risk of repair failure. Biologic augmentation of massive RC tears utilizing scaffolds-capable of regenerating bulk tendon tissue to achieve a mechanically functional repair-represents an area of increasing clinical interest. PURPOSE: To investigate the histological and biomechanical outcomes after the use of a novel biologic scaffold fabricated from woven electrochemically aligned collagen (ELAC) threads as a suture-holding, fully load-bearing, defect-bridging scaffold with or without mesenchymal stem cells (MSCs) compared with direct repair in the treatment of critically sized RC defects using a rabbit model. STUDY DESIGN: Controlled laboratory study. METHODS: A total of 34 New Zealand White rabbits underwent iatrogenic creation of a critically sized defect (6 mm) in the infraspinatus tendon of 1 shoulder, with the contralateral shoulder utilized as an intact control. Specimens were divided into 4 groups: (1) gap-negative control without repair; (2) direct repair of the infraspinatus tendon-operative control; (3) tendon repair using ELAC; and (4) tendon repair using ELAC + MSCs. Repair outcomes were assessed at 6 months using micro-computed tomography, biomechanical testing, histology, and immunohistochemistry. RESULTS: Specimens treated with ELAC demonstrated significantly less tendon retraction when compared with the direct repair group specimens (P = .014). ELAC + MSCs possessed comparable biomechanical strength (178 ± 50 N) to intact control shoulders (199 ± 35 N) (P = .554). Histological analyses demonstrated abundant, well-aligned de novo collagen around ELAC threads in both the ELAC and the ELAC + MSC shoulders, with ELAC + MSC specimens demonstrating increased ELAC resorption (7% vs 37%, respectively; P = .002). The presence of extracellular matrix components, collagen type I, and tenomodulin, indicating tendon-like tissue formation, was appreciated in both the ELAC and the ELAC + MSC groups. CONCLUSION: The application of MSCs to ELAC scaffolds improved biomechanical and histological outcomes when compared with direct repair for the treatment of critically sized defects of the RC in a rabbit model. CLINICAL RELEVANCE: This study demonstrates the feasibility of repairing segmental tendon defects with a load-bearing, collagen biotextile in an animal model, showing the potential applicability of RC repair supplementation using allogeneic stem cells.

Modified Grammont Soft-Tissue Distal Patellar Realignment and Medial Patellofemoral Ligament Reconstruction for Patellofemoral Instability in Pediatric Patients.

Patellar dislocation is a relatively common pediatric injury, which often results in recurrent patellofemoral instability. An increased tibial tubercle-trochlear groove distance predisposes to patellofemoral instability and can be corrected with a distal realignment procedure. Soft-tissue distal realignment procedures must be used in the pediatric population to avoid the risks of premature physeal closure associated with tibial tubercle osteotomies. Several soft-tissue distal realignment procedures have been described, with no consensus as to the optimal technique. When combined with medial patellofemoral ligament reconstruction, distal realignment procedures can restore patellofemoral stability through the entire flexion arc. This article describes a modification of the Grammont distal patellar realignment procedure in conjunction with medial patellofemoral ligament reconstruction for the management of pediatric patellofemoral instability.

Endoscopic Treatment of Calcific Tendinitis of the Gluteus Maximus: A Case Report.

CASE: Calcific tendinitis of the gluteus maximus is a rare condition with poorly described operative treatment options. We present a 51-year-old man with chronic left posterolateral hip pain because of gluteus maximus calcific tendinitis that was refractory to conservative treatment. Endoscopy was pursued given the severity and chronicity of his symptoms. The patient remains asymptomatic without recurrence. CONCLUSION: This is the first description of endoscopic management of calcific tendinitis of the gluteus maximus. This is a minimally invasive, efficacious option for management of this pathology.

The safety and efficacy of intrathecal morphine in pediatric spinal deformity surgery: a 25-year single-center experience.

PURPOSE: Pre-incision intrathecal morphine (IM) is a popular adjunct in adolescent idiopathic spinal deformity surgery. This study represents our 25-year experience with IM in all diagnostic groups undergoing posterior spinal fusion (PSF) and segmental instrumentation (SI). METHODS: Our prospective Pediatric Orthopaedic Spine Database (1992-2018) identified all patients undergoing PSF and SI. We included patients 21 years of age or less, had a PSF with SSI, and received the recommended IM dose of 9-19 mcg/kg (up to 1 mg) or no IM. We assessed demographics, pain scores, duration of surgery, time to first dose of narcotics, pediatric intensive care unit (PICU) admission, length of hospital stay, and IM complications (respiratory depression, pruritus, nausea/vomiting). RESULTS: There were 984 patients who met inclusion criteria: 760 patients received IM, 224 did not (non-IM). They were divided into 5 diagnostic groups: idiopathic, neuromuscular, syndromic, and congenital scoliosis and kyphosis. The mean first post-operative opioid following IM administration was at 16.1 h in the IM group compared to 8.7 h in the non-IM group (p = < 0.001). The post-operative pain scores in the IM groups were significantly lower (p = < 0.001). Sixteen patients (2%) in the IM group were admitted to the PICU for observation secondary to respiratory depression, none requiring re-intubation. There were no other complications related to IM. CONCLUSION: Pre-incision IM is a safe adjunct for pain management in select children in all diagnostic groups undergoing spinal deformity surgery. There were no serious complications. LEVEL OF EVIDENCE: III.

Evaluation of the Acquisition of Ultrasound Proficiency in Hand Surgery Fellows.

OBJECTIVES: To evaluate hand surgery fellow ultrasound (US) evaluations and performance of clinically relevant tasks after brief instruction. METHODS: Six hand surgery fellows completed an US assessment and a survey on US use before and 1 month after a 30-minute US course. RESULTS: The time to obtain an adequate image decreased from 4 minutes 42 seconds (4:42; range, 3:57-7:55) to 0:52 (range, 0:30-1:14; P < .001). Participants' performance for structure identification improved from 9.7 (range, 8-13) to 12 (range, 10-13) of 14 structures (P < .05). The average time to completion decreased from 14:6 (range, 12:08-18:30) to 9:34 (range, 4:40-15:54; P < .01). After instruction, all 6 participants identified and measured the cross-sectional area of the median nerve, identified and measured a zone 3 flexor tendon gap, and identified a simulated flexor digitorum profundus avulsion and its level of retraction (P < .05). Five of 6 successfully administered an US-guided injection to the extensor carpi ulnaris subsheath. CONCLUSIONS: After a 30-minute instructional session, hand surgery fellows can achieve a basic level of US competency.

The neural response properties and cortical organization of a rapidly adapting muscle sensory group response that overlaps with the frequencies that elicit the kinesthetic illusion.

Kinesthesia is the sense of limb movement. It is fundamental to efficient motor control, yet its neurophysiological components remain poorly understood. The contributions of primary muscle spindles and cutaneous afferents to the kinesthetic sense have been well studied; however, potential contributions from muscle sensory group responses that are different than the muscle spindles have not been ruled out. Electrophysiological recordings in peripheral nerves and brains of male Sprague Dawley rats with a degloved forelimb preparation provide evidence of a rapidly adapting muscle sensory group response that overlaps with vibratory inputs known to generate illusionary perceptions of limb movement in humans (kinesthetic illusion). This group was characteristically distinct from type Ia muscle spindle fibers, the receptor historically attributed to limb movement sensation, suggesting that type Ia muscle spindle fibers may not be the sole carrier of kinesthetic information. The sensory-neural structure of muscles is complex and there are a number of possible sources for this response group; with Golgi tendon organs being the most likely candidate. The rapidly adapting muscle sensory group response projected to proprioceptive brain regions, the rodent homolog of cortical area 3a and the second somatosensory area (S2), with similar adaption and frequency response profiles between the brain and peripheral nerves. Their representational organization was muscle-specific (myocentric) and magnified for proximal and multi-articulate limb joints. Projection to proprioceptive brain areas, myocentric representational magnification of muscles prone to movement error, overlap with illusionary vibrational input, and resonant frequencies of volitional motor unit contraction suggest that this group response may be involved with limb movement processing.