Opioid Medication Disposal Among Patients Following Hand Surgery.

BACKGROUND: Despite increased public awareness to dispose of unused narcotics, opioids prescribed postoperatively are retained, which may lead to drug diversion and abuse. This study assessed retention of unused opioids among hand surgery patients and describes disposal methods and barriers. METHODS: Participants undergoing hand surgery were given an opioid disposal information sheet preoperatively (N = 222) and surveyed postoperatively to assess disposal or retention of unused opioids, disposal methods, and barriers to disposal. A binomial logistic regression was conducted to assess whether age, sex, pain intensity, and/or the type of procedure were predictors of opioid disposal. RESULTS: There were 171 patients included in the analysis (n = 51 excluded; finished prescription or continued opioid use for pain control). Unused opioids were retained by 134 patients (78%) and disposal was reported by 37 patients (22%). Common disposal methods included returning opioids to a pharmacy (49%) or mixing them with an unwanted substance (24%). Reasons for retention included potential future use (54%), inconvenient disposal methods (21%), or keeping an unfilled prescription (9%). None of the patient factors analyzed (age, sex, type of procedure performed, or pain score) were predictors of disposal of unused narcotics (P > .05). CONCLUSIONS: Most patients undergoing hand surgery retained prescribed opioids for future use or due to impractical disposal methods. The most common disposal methods included returning narcotics to a pharmacy or mixing opioids with unwanted substances. Identifying predictors of disposal may provide important information when developing strategies to increase opioid disposal.

Identifying Risk Factors That Increase Analgesic Requirements at Discharge Among Patients With Burn Injuries.

Patients with burn injuries require large doses of opioids and gabapentinoids to achieve pain control and are often discharged from hospital with similar amounts. This study aimed to identify patient risk factors that increase analgesic requirements among patients with burn injuries and to determine the relationship between opioid and gabapentinoid use. Patient charts from July 1, 2015 to 2018 were reviewed retrospectively to determine analgesic requirements 24 hours before discharge. Linear mixed regression models were performed to determine patient risk factors (age, gender, history of substance misuse, TBSA of burn, length of stay in hospital, history of psychiatric illness, or surgical treatment) that may increase analgesic requirements. This study found that patients with a history of substance misuse (P = .01) or who were managed surgically (P = .01) required higher doses of opioids at discharge. Similarly, patients who had undergone surgical debridement required more gabapentinoids (P < .001). For every percent increase in TBSA, patients also required 14 mg more gabapentinoids (P = .01). In contrast, older patients (P = .006) and those with a longer hospital stay (P = .009) required fewer amounts of gabapentinoids before discharge. By characterizing factors that increase analgesic requirements at discharge, burn care providers may have a stronger understanding of which patients are at greater risk of developing chronic opioid or gabapentinoid misuse. The quantity and duration of analgesics prescribed at discharge may then be tailored according to these patient specific risk factors.

Comparing Flap Advancement and Wound Coverage of Anterograde Homodigital Neurovascular Island Flap Designs: A Cadaveric Model.

PURPOSE: Anterograde homodigital neurovascular island flaps are a reconstructive option for volar fingertip injuries and confer the advantage of preserving fingertip sensation after surgery. However, the amount of flap advancement and wound coverage provided by stepwise and triangular flap designs remains unknown. This study sought to investigate how incremental proximal dissection of the pedicle influences flap advancement and whether advancement and/or coverage differ between the triangular and stepwise flap designs using 22 paired cadaveric digits. METHODS: Flap advancement and wound coverage were evaluated in a pairwise design such that each pair of digits received 1 stepwise flap and 1 triangular flap. After creating a standardized injury to the volar fingertip, pedicled flaps were dissected from the middle phalanx and advanced distally under consistent tension. Advancement was measured for each 5 mm of proximal mobilization of the pedicle to a maximum of 30 mm. RESULTS: On average, 2.6 ± 0.2 mm of flap advancement could be achieved for every 10 mm of pedicle mobilization. With 30 mm of proximal mobilization of the pedicle, 11.8 ± 2.8 mm of advancement and 57.2% ± 16.1% of wound coverage could be expected. There were no significant differences between the flap designs. CONCLUSIONS: The stepwise and triangular anterograde homodigital neurovascular island flaps offer comparable and consistent reconstructive outcomes for volar fingertip injuries. CLINICAL RELEVANCE: The findings in this study suggest that the choice of flap design need not be influenced by the considerations of advancement or coverage; rather, surgeon preference or technical differences between the 2 flap designs may be of more importance.

COVID-19 Restrictions Presented Opportunities and Challenges for Plastic Surgery Residents.

BACKGROUND: Restrictions placed during the COVID-19 pandemic to prevent viral spread led to substantial changes in surgical resident education. The aim of this study was to assess the positive and negative impact of COVID-19 on plastic surgery education and training and provide recommendations for continued competency. METHODS: A cross-sectional online survey of plastic surgery residents across Canada was used to evaluate the impact of COVID-19 on clinical exposure, experience with virtual education, and long-term impact of COVID-19 on surgical training. RESULTS: This study included 61 plastic surgery residents (40% participation rate). Common educational modalities used during COVID-19 included online seminars (95%) and workshops (58%). Teaching sessions were effective if structured around patient cases (72%), recorded (66%), and limited to 1 hour (64%). There were mixed reactions towards online education sessions; residents reported feeling grateful (54%), motivated (38%), enthusiastic (28%), overwhelmed (41%), pressured to participate (23%), and anxious (13%). There were significantly less residents who felt that their clinical exposure was sufficient during (21%) versus before (72%) pandemic restrictions (P < .001). Overall, 87% of residents felt that the pandemic had a negative impact on their training, surgical skill development, fellowship plans, and job prospects. CONCLUSIONS: During the initial wave of COVID-19, residents faced altered educational opportunities, which elicited positive and negative emotions with concern regarding surgical skill development and impact on future career plans. Characterizing early educational impact on residency training to identify opportunities for change is worthwhile as the overall effect of the pandemic is ongoing and remains uncertain.

HISTORIQUE: Les restrictions imposées pendant la pandémie de COVID-19 pour en éviter la propagation virale ont entraîné des changements importants dans la formation des résidents en chirurgie. La présente étude visait à évaluer les répercussions positives et négatives de la COVID-19 sur l'enseignement et la formation en chirurgie plastique et à formuler des recommandations sur le maintien des compétences. MÉTHODOLOGIE: Les chercheurs ont utilisé un sondage transversal en ligne auprès des résidents en chirurgie plastique du Canada pour évaluer les répercussions de la COVID-19 sur l'exposition clinique, l'expérience de l'enseignement virtuel et les conséquences à long terme de la COVID-19 pour la formation en chirurgie. RÉSULTATS: La présente étude incluait 61 résidents en chirurgie plastique (pour un taux de participation de 40%). Les modes d'enseignement couramment utilisés pendant la COVID-19 incluaient les séminaires en ligne (95%) et les ateliers (58%). Les séances d'enseignement étaient efficaces si elles étaient structurées autour de cas de patients (72%), enregistrées (66%) et se limitaient à une heure (64%). Les réactions étaient mitigées quant aux séances de formation en ligne. Les résidents ont déclaré se sentir reconnaissants (54%), motivés (38%), enthousiastes (28%), dépassés (41%), poussés à participer (23%) et anxieux (13%). Beaucoup moins de résidents avaient l'impression que leur exposition clinique avait été suffisante pendant les restrictions liées à la pandémie (21%) qu'auparavant (72%; p<0,001). Dans l'ensemble, 87% des résidents trouvaient que la pandémie avait un effet négatif sur leur formation, l'acquisition de leurs compétences chirurgicales, leurs projets de surspécialité et leurs perspectives professionnelles. CONCLUSIONS: Pendant la première vague de COVID-19, les résidents ont dû composer avec des modifications à leurs possibilités de formation, qui ont donné lieu à des émotions positives et négatives et à des inquiétudes quant à l'acquisition de leurs habiletés chirurgicales et aux répercussions sur leur plan de carrière. Il est intéressant de caractériser les répercussions précoces sur la formation en résidence pour déterminer les occasions de changement, car l'effet global de la pandémie se poursuit et demeure incertain.

Identifying barriers to upper extremity reconstruction in tetraplegia: a systematic scoping review.

STUDY DESIGN: Systematic scoping review OBJECTIVES: The purpose of this study was to understand the barriers to accessing upper extremity (UE) reconstructive surgery among those living with tetraplegia, and to identify gaps in knowledge. METHODS: Using standardized scoping review methods, a literature search was conducted using four databases and 1069 articles were procured. Two independent reviewers systematically screened the articles in two phases. Retrieved articles underwent thematic analysis using a constructivist grounded theory methodology. RESULTS: The reviewed articles (n = 25) were published between 2002 and 2019, and study designs included: cross-sectional (64%), retrospective (16%), and review articles (8%). Common barriers to UE reconstruction were categorized into factors related to patients, providers, and systems. These general domains included lack of awareness of UE reconstruction and its benefits among people with tetraplegia and providers, poor interdisciplinary working relationships, and a lack of specialized centers that provide these reconstructive surgeries. Specific patient-related barriers related to intrinsic (coping skills, trust, fear) and extrinsic (support network, finances, postoperative course) factors that influenced decision-making. CONCLUSIONS: There are many barriers that prevent individuals with tetraplegia from accessing surgery at different levels of the healthcare system. Establishing specialized centers with strong interdisciplinary working relationships and raising awareness about the advantages and disadvantages of UE reconstruction through peer networks may help to improve accessibility. Using a value-based, patient-centered approach by exploring how individuals with SCI weigh each decision factor when considering surgery may help providers develop treatment options that better align with their goals.

Prescribing patterns of opioids and adjunctive analgesics for patients with burn injuries.

PURPOSE: Large quantities of analgesics are prescribed to control pain among patients with burn injuries and may lead to chronic use and dependency. This study aimed to determine whether patients are overprescribed analgesics at discharge and to identify factors that influence prescribing patterns. MATERIAL AND METHODS: A retrospective review of patient charts (n = 199) between July 1, 2015-2018 were reviewed from a registry at a single burn center. Opioid, neuropathic pain agent, acetaminophen, and ibuprofen quantities given before and at discharge were compared. Linear mixed regression models were used to identify factors that increased the amount of analgesics prescribed. RESULTS: On average, patients were prescribed significantly more analgesics at discharge compared to what was consumed pre-discharge (p < 0.0001). Specifically, on average, providers did not overprescribe the daily dose, but overprescribed the duration of pain medications required. For every increase in percent TBSA, 14 MEQ more opioids, 203 mg more neuropathic pain agents, 843 mg more acetaminophen, and 126 mg more ibuprofen were prescribed (p < 0.05). Surgery was a predictor for higher opioid and neuropathic pain agent prescriptions (p = 0.03), while length of stay was associated with fewer neuropathic pain agents prescribed (p = 0.04). Fewer ibuprofen were given to patients with a history of substance misuse (p = 0.01). CONCLUSIONS: The quantity of analgesics prescribed at discharge varied widely and often prescribed for long durations of time. Standardized prescribing guidelines should be developed to optimize how analgesics are prescribed at discharge.

Canadian Plastic Surgery Resident Operative Experience in Hand Surgery.

PURPOSE: Core procedural competencies (CPCs) in hand surgery have been previously described. However, it is unknown whether plastic surgery residents receive sufficient operative experience with these procedures. This study aimed to determine whether Canadian plastic surgery residents are receiving adequate exposure to CPCs in hand surgery during residency training. METHODS: Hand surgery case logs recorded by graduating plastic surgery residents at 10 Canadian English-speaking training programs between 2004 and 2014 were reviewed from 3 databases. For each CPC in hand surgery, perceived resident role and self-competence scores were collected and analyzed. Core procedural competencies encompass core essential procedural competencies (CEPCs) and nonessential procedural competencies. RESULTS: There were 55 graduating plastic surgery residents included in the study. A total of 14,909 procedures were logged for 42 CPCs, with an average of 271 procedures/resident. When grouped by subdomain within hand surgery, procedures with the most exposure were related to traumatic finger injuries (29%) and neuropathies (22%). The least common procedures were related to flap reconstructions (0.3%) and muscle release (0.1%). Many residents reported receiving no operative experience (range, 2% to 100%) or between 1 and 10 cases of CEPCs (range, 7% to 50%). Most graduating residents (58% to 72%) did not feel competent independently performing 60% of the most common procedures. There were weak to moderate correlations between role and self-competence, and between postgraduate year and self-competence. CONCLUSIONS: Currently, many plastic surgery residents graduate from training programs with little to no exposure for over half of the CEPCs in hand surgery. CLINICAL RELEVANCE: Given the great diversity in hand surgery CPCs, it is difficult for residents to gain adequate operative experience during their residency in all of the CPCs.

Variable Experience in Microsurgery and Flap-Based Procedures Among Canadian Plastic Surgery Residents.

TITLE: Variable experience in microsurgery and flap-based procedures among Canadian plastic surgery residents. OBJECTIVE: Plastic surgery residencies are transitioning toward a competency-based education model. It is not known whether trainees can realistically achieve proficiency in microsurgical techniques during their training. This study aims to define the operative experience in the core microsurgical flap procedures among Canadian plastic surgery residents. DESIGN: Microsurgical core procedural competencies (CPCs) have been described. A retrospective review was conducted, evaluating case logs recorded by graduating plastic surgery residents at 10 Canadian English-speaking training programs between 2004 and 2014. Perceived role and competence scores were also collected and analyzed. SETTING: University of Toronto, Toronto, ON, Canada; University of British Columbia, Vancouver, BC, Canada. RESULTS: Among 27 microsurgical CPCs, 2082 procedures were logged and each resident performed an average of 37.9 (±21.7) procedures. Anterolateral thigh flaps, radial forearm-based flaps, and digit replants were the most common; however, 10.9% to 14.5% of residents did not have any operative experience with these flaps. Most residents reported zero operative experience with many of the CPCs (10.9%-100%). Co-Surgeon (50%) and First Assistant (30%) were the most common roles. None of the graduating residents reported feeling competent enough to independently perform 50% of the microsurgery CPCs. There was no difference in perceived roles when programs with ≥5 residents were compared against programs with fewer trainees. There were weak to moderate correlations between role and self-perceived competence, and between Post Graduate Year and self-perceived competence. CONCLUSIONS: There is wide variation in resident operative experience in microsurgical CPCs. Many residents graduate with little to no experience in many of the core procedures. Identifying areas of deficiency may help guide curriculum development in the new competency-based education model.

What you see is not always what you get: Radiographic-pathologic discordance among benign breast masses.

The differential diagnosis for benign breast masses is broad and ranges from common lesions like fibroadenomas to rare masses like breast hamartomas. Fibroadenomas are proliferative benign masses made up of fibroglandular tissue. Hamartomas are neoplasms comprised of different tissues that are endogenous to the area where they originate. Breast hamartomas specifically, are rare, benign slow growing tumours comprised of fibrotic stroma, adipose, glandular tissue, and epithelial components. Both lesions are painless, firm, and are typically palpable on clinical exam. Given their similarities in composition, diagnosing these masses can be challenging, but may be confirmed with ultrasonography, mammogram, computed tomography, magnetic resonance imaging, or via histological specimen. Once diagnosed, surgical excision is the preferred treatment option. We present a 33-year-old woman with a large left breast mass that gradually increased in size and provide a review of the current literature regarding the challenge of distinguishing between breast fibroadenomas and hamartomas.

Variation in Treatment Recommendations for Dupuytren Disease.

PURPOSE: To examine agreement on Dupuytren disease (DD) treatment recommendations in an international sample of hand surgeons. METHODS: A survey was developed to determine expertise in needle aponeurotomy, surgery, and collagenase injection to treat DD and to examine treatment recommendations for 16 case scenarios. Case scenarios were predeveloped using expert input. Each case represented a unique combination of 4 dichotomous variables including cord thickness, contracture severity, patient age, and joint involvement. Interrater reliability statistics were calculated and multinomial logistic regression modeling and analysis of variance were used to examine the impact of surgeon- and case-related variables on treatment recommendations. RESULTS: A total of 36 hand surgeons from 9 countries (mean experience, 17 years) participated. Average pairwise percent agreement and Krippendorff's alpha were 26% and .012, respectively. Predictors of a recommendation for surgery over multiple options were a total contracture of greater than 70°, a thick precentral cord, involvement of the metacarpophalangeal and proximal interphalangeal joints, and greater years in practice. A greater number of years in practice predicted recommendation for collagenase injection and the presence of a thick precentral cord predicted a recommendation for needle aponeurotomy. CONCLUSIONS: Little agreement exists on treatment recommendations for common presentations of DD in this sample. CLINICAL RELEVANCE: Further investigation into the sources of potential widespread discrepancies in the management of DD may improve the capacity to make evidence-based recommendations.

Developing Cognitive Task Analysis-based Educational Videos for Basic Surgical Skills in Plastic Surgery.

OBJECTIVE: To describe the development of cognitive task analysis (CTA)-based multimedia educational videos for surgical trainees in plastic surgery. DESIGN: A needs assessment survey was used to identify 5 plastic surgery skills on which to focus the educational videos. Three plastic surgeons were video-recorded performing each skill while describing the procedure, and were interviewed with probing questions. Three medical student reviewers coded transcripts and categorized each step into "action," "decision," or "assessment," and created a cognitive demands table (CDT) for each skill. The CDTs were combined into 1 table that was reviewed by the surgeons performing each skill to ensure accuracy. The final CDTs were compared against each surgeon's original transcripts. The total number of steps identified, percentage of steps shared, and the average percentage of steps omitted were calculated. SETTING: Sunnybrook Health Sciences Centre, Toronto, Ontario, Canada, an urban tertiary care teaching center. PARTICIPANTS: Canadian junior plastic surgery residents (n = 78) were sent a needs assessment survey. Four plastic surgeons and 1 orthopedic surgeon performed the skills. RESULTS: Twenty-eight residents responded to the survey (36%). Subcuticular suturing, horizontal and vertical mattress suturing, hand splinting, digital nerve block, and excisional biopsy had the most number of residents (>80%) rank the skills as being skills that students should be able to perform before entering residency. The number of steps identified through CTA ranged from 12 to 29. Percentage of steps shared by all 3 surgeons for each skill ranged from 30% to 48%, while the average percentage of steps that were omitted by each surgeon ranged from 27% to 40%. CONCLUSIONS: Instructional videos for basic surgical skills may be generated using CTA to help experts provide comprehensive descriptions of a procedure. A CTA-based educational tool may give trainees access to a broader, objective body of knowledge, allowing them to learn decision-making processes before entering the operating room.

Development and implementation of a longitudinal students as teachers program: participant satisfaction and implications for medical student teaching and learning.

BACKGROUND: Teaching is a key component of medical practice, but medical students receive little formal training to develop their teaching skills. A longitudinal Students as Teachers (SAT) program was created at the University of Toronto to provide medical students with opportunities to acquire an understanding of educational pedagogy and practice teaching early in their medical training. This program was 7-months in duration and consisted of monthly educational modules, practical teaching sessions, feedback, and reflective exercises. METHODS: A mixed methods study design was used to evaluate initial outcomes of the SAT program by obtaining the perspectives of 18 second-year medical students. Participants filled out questionnaires at the beginning and end of the 7-month program to indicate their skill level and confidence in teaching. Differences between pre- and post-intervention scores were further explored in a group interview of 5 participants. RESULTS: Participants expressed a high degree of satisfaction with the SAT program structure and found the educational modules and practical teaching sessions to be particularly beneficial to their learning. Over the course of the program, there were significant increases in students' confidence in teaching, and self-perceived teaching capacity and communication skills. Furthermore, participants discussed improvements in their effectiveness as learners. CONCLUSIONS: Teaching is a skill that requires ongoing practice. Our results suggest that a longitudinal program consisting of theoretical modules, practical teaching sessions, feedback, and reflective exercises for medical students may improve teaching and communication skills, and equip them with improved learning strategies. This program also provides students with insight into the experience of teaching while holding other academic and clinical responsibilities.

Video assessment of laparoscopic skills by novices and experts: implications for surgical education.

BACKGROUND: Previous investigators have shown that novices are able to assess surgical skills as reliably as expert surgeons. The purpose of this study was to determine how novices and experts arrive at these graded scores when assessing laparoscopic skills and the potential implications this may have for surgical education. METHODS: Four novices and four general laparoscopic surgeons evaluated 59 videos of a suturing task using a 5-point scale. Average novice and expert evaluator scores for each video and the average number of times that scores were changed were compared. Intraclass correlation coefficients were used to determine inter-rater and test-retest reliability. Evaluators were asked to define the number of videos they needed to watch before they could confidently grade and to describe how they were able to distinguish between different levels of expertise. RESULTS: There were no significant differences in mean scores assigned by the two evaluator groups. Novices changed their scores more frequently compared to experts, but this did not reach statistical significance. There was excellent inter-rater reliability between the two groups (ICC = 0.91, CI 0.85-0.95) and good test-retest reliability (ICC > 0.83). On average, novices and experts reported that they needed to watch 13.8 ± 2.4 and 8.5 ± 2.5 videos, respectively, before they could confidently grade. Both groups also identified similar qualitative indicators (e.g., instrument control). CONCLUSION: Evaluators with varying levels of expertise can reliably grade performance of an intracorporeal suturing task. While novices were less confident in their grading, both groups were able to assign comparable scores and identify similar elements of a suturing skill as being important in terms of assessment.

A Peer-Reviewed Instructional Video is as Effective as a Standard Recorded Didactic Lecture in Medical Trainees Performing Chest Tube Insertion: A Randomized Control Trial.

OBJECTIVE: Online medical education resources are becoming an increasingly used modality and many studies have demonstrated their efficacy in procedural instruction. This study sought to determine whether a standardized online procedural video is as effective as a standard recorded didactic teaching session for chest tube insertion. DESIGN: A randomized control trial was conducted. Participants were taught how to insert a chest tube with either a recorded didactic teaching session, or a New England Journal of Medicine (NEJM) video. Participants filled out a questionnaire before and after performing the procedure on a cadaver, which was filmed and assessed by 2 blinded evaluators using a standardized tool. SETTING: Western University, London, Ontario. Level of clinical care: institutional. PARTICIPANTS: A total of 30 fourth-year medical students from 2 graduating classes at the Schulich School of Medicine & Dentistry were screened for eligibility. Two students did not complete the study and were excluded. There were 13 students in the NEJM group, and 15 students in the didactic group. RESULTS: The NEJM group׳s average score was 45.2% (±9.56) on the prequestionnaire, 67.7% (±12.9) for the procedure, and 60.1% (±7.65) on the postquestionnaire. The didactic group׳s average score was 42.8% (±10.9) on the prequestionnaire, 73.7% (±9.90) for the procedure, and 46.5% (±7.46) on the postquestionnaire. There was no difference between the groups on the prequestionnaire (Δ + 2.4%; 95% CI: -5.16 to 9.99), or the procedure (Δ -6.0%; 95% CI: -14.6 to 2.65). The NEJM group had better scores on the postquestionnaire (Δ + 11.15%; 95% CI: 3.74-18.6). CONCLUSIONS: The NEJM video was as effective as video-recorded didactic training for teaching the knowledge and technical skills essential for chest tube insertion. Participants expressed high satisfaction with this modality. It may prove to be a helpful adjunct to standard instruction on the topic.

Regional Variations in Cartilage Thickness of the Radial Head: Implications for Prosthesis Design.

PURPOSE: To characterize the regional variations in cartilage thickness around the radial head. METHODS: We dissected 27 cadaveric radii and scanned them with computed tomography in neutral position. Three-dimensional cartilage and subchondral bone surface models were generated from computed tomography scans and 2 independent observers processed them through a computer program to obtain cartilage thickness measurements. These measurements were taken at 41 predetermined landmarks around the periphery of the radial head and within the articular dish. RESULTS: At the periphery of the radial head, cartilage was thickest in the posteromedial region. Thickness values within the articular dish were similar but increased toward the rim. Regional variations within the rim (range, 0.76-1.73 mm) were also detected with the thickest region located anteriorly and thinnest region laterally. In addition, cartilage was significantly thicker in male relative to female specimens. CONCLUSIONS: Regional variations in cartilage thickness are present around the periphery and rim and within the articular dish of the radial head. CLINICAL RELEVANCE: Cartilage thickness across the articular dish may contribute to dish depth and the radius of curvature. This may be clinically important for the design of anatomic implants, because accounting for such subtle contours could help to restore radiocapitellar concavity-compression stability better.

The effect of fracture comminution on the reliability and accuracy of radial head sizing.

BACKGROUND: Radial head implant sizing can be based on the maximum head diameter (D-MAX), the minimum head diameter (D-MIN), or the articular dish diameter (D-DISH). The purpose of this study was to assess the reliability of the different radial head sizing techniques and to investigate the effect of radial head fracture comminution on measurement accuracy. METHODS: Ten observers measured 11 cadaveric radial heads with 3 radial head features (D-MAX, D-MIN, and D-DISH diameter). Radial heads were then fractured into 2, 3, and 4 parts, and the measurements were repeated. Variability was assessed by intraclass correlation. The measurements were compared with the intact state to assess the effect of radial head fracture comminution on sizing accuracy. RESULTS: D-MAX and D-MIN measurements were the most reliable among all observers (intraclass correlation coefficients, 0.980, 0.973). The D-DISH measurement was less reliable (intraclass correlation coefficient, 0.643). Radial head comminution did not significantly affect the reliability of any measurement (P > .2). Fracture comminution, however, significantly affected measurement accuracy with D-MAX and D-DISH. With fracture comminution, D-MAX underestimated radial head diameter (-0.4 ± 0.3 mm; P < .001), whereas D-DISH overestimated diameter (+0.5 ± 0.4 mm; P < .001). Comminution did not significantly affect D-MIN (-0.1 ± 0.3 mm; P = .13). DISCUSSION: The D-MAX and D-MIN measurements were more reliable than D-DISH for diameter sizing of intact and comminuted radial heads. Overall, increasing comminution did not significantly affect measurement reliability. However, the accuracy of the D-MIN technique was least affected by comminution, suggesting that D-MIN should be used in selecting the diameter of a radial head implant.

Oncostatin M regulates osteogenic differentiation of murine adipose-derived mesenchymal progenitor cells through a PKCdelta-dependent mechanism.

Oncostatin M (OSM) is an IL-6/LIF family cytokine that influences mesenchymal progenitor differentiation; however, the mechanisms of this activity have not been fully elucidated. Using uncommitted murine adipose tissue-derived mesenchymal progenitors, we have examined mechanisms of OSM-induced osteogenesis. Murine OSM (mOSM) induced osteogenic differentiation to a greater degree than interleukin (IL)-6 and other members of the gp130 cytokine family, promoting extracellular matrix mineralization as indicated by Alizarin Red S staining. mOSM also increased expression of osteogenesis-associated gene products BMP4, BMP7, Runx-2, and osteocalcin as assessed by immunoblotting and real-time quantitative PCR. Additionally, protein kinase C (PKC) delta activity was upregulated in response to OSM stimulation, and to a greater degree than IL-6. Knockdown of PKCdelta expression by use of RNA interference (RNAi) reduced OSM-mediated osteogenic differentiation and decreased expression of Runx-2. These findings suggest that OSM differentially promotes osteogenesis in non-committed mesenchymal progenitors relative to other gp130 cytokines. This activity correlates with selective activation of PKCdelta in OSM-treated cells, indicating that OSM-induced osteogenesis and upregulation of osteogenic gene products require activity of PKCdelta.