Evaluation of Mid-term Outcomes Following Shoulder Hemiarthroplasty for Avascular Necrosis of the Humeral Head in Patients 40 Years and Younger.

In order to evaluate postoperative function and failure rates among younger patients undergoing hemiarthroplasty for humeral head avascular necrosis (AVN), data from patients < 40 years treated between December 2008 - January 2018 was retrospectively analyzed. Pain was assessed preoperatively and at final follow up using a visual analogue scale (VAS). The American Shoulder and Elbow Surgeons (ASES) standardized assessment, single assessment numeric evaluation (SANE) score, and patient satisfaction were assessed at final follow up, as well as surgical revision rates. In total, eight shoulders were included in the final analysis, with a follow up of 6.6 + 3.6 years. Analysis indicated a statistical improvement in VAS pain (p = 0.001), while comparison of postoperative function between surgical and non-surgical limbs did not demonstrate statistical differences in SANE or ASES averages (p > 0.05). At final follow up, 25% of patients expressed dissatisfaction; however, there were no cases of revision surgery. In conclusion, younger patients undergoing hemiarthroplasty for humeral head AVN experienced pain improvement and no revisions at short-to-mid-term follow up, but one-in-four indicated dissatisfaction. Level of evidence: IV, case series. (Journal of Surgical Orthopaedic Advances 32(2):118-121, 2023).

Is Grit Associated with Burnout and Well-being in Orthopaedic Resident and Faculty Physicians? A Multi-institution Longitudinal Study Across Training Levels.

BACKGROUND: Grit has been defined as "perseverance and passion for long-term goals" and is characterized by maintaining focus and motivation toward a challenging ambition despite setbacks. There are limited data on the impact of grit on burnout and psychologic well-being in orthopaedic surgery, as well as on which factors may be associated with these variables. QUESTIONS/PURPOSES: (1) Is grit inversely correlated with burnout in orthopaedic resident and faculty physicians? (2) Is grit positively correlated with psychologic well-being in orthopaedic resident and faculty physicians? (3) Which demographic characteristics are associated with grit in orthopaedic resident and faculty physicians? (4) Which demographic characteristics are associated with burnout and psychologic well-being in orthopaedic resident and faculty physicians? METHODS: This study was an institutional review board-approved interim analysis from the first year of a 5-year longitudinal study of grit, burnout, and psychologic well-being in order to assess baseline relationships between these variables before analyzing how they may change over time. Orthopaedic residents, fellows, and faculty from 14 academic medical centers were enrolled, and 30% (335 of 1129) responded. We analyzed for the potential of response bias and found no important differences between sites in low versus high response rates, nor between early and late responders. Participants completed an email-based survey consisting of the Duckworth Short Grit Scale, Maslach Burnout Inventory-Human Services (Medical Personnel) Survey, and Dupuy Psychological Well-being Index. The Short Grit Scale has been validated with regard to internal consistency, consensual and predictive validity, and test-retest stability. The Psychological Well-being Index has similarly been validated with regard to reliability, test-retest stability, and internal consistency, and the Maslach Burnout Inventory has been validated with regard to internal consistency, reliability, test-retest stability, and convergent validity. The survey also obtained basic demographic information such as survey participants' age, gender, race, ethnicity, marital status, current year of training or year in practice (as applicable), and region of practice. The studied population consisted of 166 faculty, 150 residents, and 19 fellows. Beyond the expected age differences between sub-populations, the fellow population had a higher proportion of women than the faculty and resident populations did. Pearson correlations and standardized ß coefficients were used to assess the relationships of grit, burnout, psychologic well-being, and continuous participant characteristics. RESULTS: We found moderate, negative relationships between grit and emotional exhaustion (r = -0.30; 95% CI -0.38 to -0.21; p < 0.001), depersonalization (r = -0.34; 95% CI -0.44 to -0.23; p < 0.001), and the overall burnout score (r = -0.39; 95% CI -0.48 to -0.31; p < 0.001). The results also showed a positive correlation between grit and personal accomplishment (r = 0.39; 95% CI 0.29 to 0.48; p < 0.001). We also found a moderate, positive relationship between grit and psychologic well-being (r = 0.39; 95% CI 0.30 to 0.49; p < 0.001). Orthopaedic surgeons with 21 years or more of practice had higher grit scores than physicians with 10 to 20 years of practice. Orthopaedic surgeons in practice for 21 years or more also had lower burnout scores than those in practice for 10 to 20 years. Married physicians had higher psychologic well-being than unmarried physicians did. CONCLUSION: Among orthopaedic residents, fellows, and faculty, grit is inversely related to burnout, with lower scores for emotional exhaustion and depersonalization and higher scores for personal accomplishment as grit increases. CLINICAL RELEVANCE: The results suggest that grit could be targeted as an intervention for reducing burnout and promoting psychologic well-being among orthopaedic surgeons. Other research has suggested that grit is influenced by internal characteristics, life experiences, and the external environment, suggesting that there is potential to increase one's grit. Residency programs and faculty development initiatives might consider measuring grit to assess for the risk of burnout, as well as offering curricula or training to promote this psychologic characteristic.

Peripheral Nerve Injury After Elbow Arthroscopy: An Analysis of Risk Factors.

PURPOSE: To identify risk factors associated with peripheral nerve injury after elbow arthroscopy and provide an updated incidence of those complications. METHODS: The elbow arthroscopies that were performed at our institution between 2006 and 2016 were identified. Over a 10-year period, 253 elbow arthroscopies were performed at our institution. Two hundred twenty-seven cases had a minimum follow-up of 4 weeks, and were included in our analysis. Minor and major nerve-related complications were recorded. The surgeon's experience and training, body max index of the patients, surgical tourniquet time, type of anesthesia or surgery, radiographic appearance of the elbow, diagnosis at the time of surgery, and presence of diabetes were analyzed. RESULTS: There were 12 reported peripheral nerve injuries, 10 minor (4.4%) and 2 major complications (0.9%). The risk factors examined in this study were not correlated with a higher rate of complications. CONCLUSIONS: The minor nerve-related complication rate was 4.4%, with a 0.9% incidence of major peripheral nerve injury. Based on these findings, we conclude that elbow arthroscopy is a relatively safe procedure. The risk factors examined in this study had no association with the rate of complications. This finding could be potentially related to type II or beta error in the analysis of risk factors for nerve injury. The exact reasons for nerve injury are not known from this study. LEVEL OF EVIDENCE: Level IV, retrospective case series.

Extensive Hand Thermal and Blast Injury From Electronic Cigarette Explosion: A Case Report.

Background: As the use of electronic cigarettes rises, more reports of injuries related to device explosion are surfacing. Methods: Presented here is the case of a 35-year-old man sustaining extensive thermal and blast injuries to his hand when the device exploded while he was holding it. He required multiple surgeries involving groin flap coverage, tendon transfer, and nerve grafting to optimize his postinjury function. Results: While much of his hand function has been restored, he has continued deficits in range of motion and sensation as a result of the incident. Conclusions: With increasing numbers of such injuries, hand surgeons must be aware of the blast mechanism involved so as to avoid missing deep soft tissue injury or disruption of deep structures, as demonstrated in this case.

Assessments of Fatty Infiltration and Muscle Atrophy From a Single Magnetic Resonance Image Slice Are Not Predictive of 3-Dimensional Measurements.

PURPOSE: To (1) determine whether standard clinical muscle fatty infiltration and atrophy assessment techniques using a single image slice for patients with a rotator cuff tear (RCT) are correlated with 3-dimensional measures in older individuals (60+ years) and (2) to determine whether age-associated changes to muscle morphology and strength are compounded by an RCT. METHODS: Twenty older individuals were studied: 10 with an RCT of the supraspinatus (5 men and 5 women) and 10 matched controls. Clinical imaging assessments (Goutallier and Fuchs scores and cross-sectional area ratio) were performed for participants with RCTs. Three-dimensional measurements of rotator cuff muscle and fat tissues were obtained for all participants using magnetic resonance imaging (MRI). Isometric joint moment was measured at the shoulder. RESULTS: There were no significant associations between single-image assessments and 3-dimensional measurements of fatty infiltration for the supraspinatus and infraspinatus muscles. Compared with controls, participants with RCTs had significantly increased percentages of fatty infiltration for each rotator cuff muscle (all P ≤ .023); reduced whole muscle volume for the supraspinatus, infraspinatus, and subscapularis muscles (all P ≤ .038); and reduced fat-free muscle volume for the supraspinatus, infraspinatus, and subscapularis muscles (all P ≤ .027). Only the teres minor (P = .017) fatty infiltration volume was significantly greater for participants with RCTs. Adduction, flexion, and external rotation strength (all P ≤ .021) were significantly reduced for participants with RCTs, and muscle volume was a significant predictor of strength for all comparisons. CONCLUSIONS: Clinical scores using a single image slice do not represent 3-dimensional muscle measurements. Efficient methods are needed to more effectively capture 3-dimensional information for clinical applications. Participants with RCTs had increased fatty infiltration percentages that were likely driven by muscle atrophy rather than increased fat volume. The significant association of muscle volume with strength production suggests that treatments to preserve muscle volume should be pursued for older patients with RCTs. LEVEL OF EVIDENCE: Level II, diagnostic study, with development of diagnostic criteria on the basis of consecutive patients with universally applied reference gold standard.

Advanced age diminishes tendon-to-bone healing in a rat model of rotator cuff repair.

BACKGROUND: Advanced patient age is associated with recurrent tearing and failure of rotator cuff repairs clinically; however, basic science studies have not evaluated the influence of aging on tendon-to-bone healing after rotator cuff repair in an animal model. Hypothesis/ PURPOSE: This study examined the effect of aging on tendon-to-bone healing in an established rat model of rotator cuff repair using the aged animal colony from the National Institute on Aging of the National Institutes of Health. The authors hypothesized that normal aging decreases biomechanical strength and histologic organization at the tendon-to-bone junction after acute repair. STUDY DESIGN: Controlled laboratory study. METHODS: In 56 F344xBN rats, 28 old and 28 young (24 and 8 months of age, respectively), the supraspinatus tendon was transected and repaired. At 2 or 8 weeks after surgery, shoulder specimens underwent biomechanical testing to compare load-to-failure and load-relaxation response between age groups. Histologic sections of the tendon-to-bone interface were assessed with hematoxylin and eosin staining, and collagen fiber organization was assessed by semiquantitative analysis of picrosirius red birefringence under polarized light. RESULTS: Peak failure load was similar between young and old animals at 2 weeks after repair (31% vs 26% of age-matched uninjured controls, respectively; P > .05) but significantly higher in young animals compared with old animals 8 weeks after repair (86% vs 65% of age-matched uninjured controls, respectively; P < .01). Eight weeks after repair, fibroblasts appeared more organized and uniformly aligned in young animals on hematoxylin and eosin slides compared with old animals. Collagen birefringence analysis of the tendon-to-bone junction demonstrated that young animals had increased collagen fiber organization and similar histologic structure compared with age-matched controls (53.7 ± 2.4 gray scales; P > .05). In contrast, old animals had decreased collagen fiber organization and altered structure compared with age-matched controls (49.8 ± 3.1 gray scales; P < .01). DISCUSSION: In a rat model of aging, old animals demonstrated diminished tendon-to-bone healing after rotator cuff injury and repair. Old animals had significantly decreased failure strength and collagen fiber organization at the tendon-to-bone junction compared with young animals. This study implies that animal age may need to be considered in future studies of rotator cuff repair in animal models. CLINICAL RELEVANCE: With increasing age and activity level of the population, the incidence of rotator cuff tears is predicted to rise. Despite advances in rotator cuff repair technique, the retear rate remains specifically high in elderly patients. The findings of this research suggest that aging negatively influences tendon-to-bone healing after rotator cuff repair in a validated animal model.

Age-related changes affect rat rotator cuff muscle function.

BACKGROUND: The influence of age on rotator cuff function and muscle structure remains poorly understood. We hypothesize that normal aging influences rotator cuff function, muscle structure, and regulatory protein expression in an established rat model of aging. METHODS: Seventeen rats were obtained from the National Institute on Aging. The supraspinatus muscles in 11 middle-aged (12 months old) and 6 old (28 months old) rats were studied for age-related changes in rotator cuff neuromuscular function by in vivo muscle force testing and electromyography (EMG). Changes in muscle structure and molecular changes were assessed with quantitative immunohistochemistry for myogenic determination factor 1 (MyoD) and myogenic factor 5 (Myf5) expression. RESULTS: Old animals revealed significantly decreased peak tetanic muscle force at 0.5 N and 0.7 N preload tension (P < .05). The age of the animal accounted for 20.9% of variance and significantly influenced muscle force (P = .026). Preload tension significantly influenced muscle force production (P < .001) and accounted for 12.7% of total variance. There was regional heterogeneity in maximal compound motor action potential (CMAP) amplitude in the supraspinatus muscle; the proximal portion had a significantly higher CMAP than the middle and distal portions (P < .05). The expression of muscle regulatory factors MyoD and Myf5 was significantly decreased in old animals compared with middle-aged animals (P < .05). CONCLUSIONS: The normal aging process in this rat model significantly influenced contractile strength of the supraspinatus muscle and led to decreased expression of muscle regulatory factors. High preload tensions led to a significant decrease in force production in both middle-aged and old animals.

Age-related degenerative functional, radiographic, and histological changes of the shoulder in nonhuman primates.

BACKGROUND: Nonhuman primates have similar shoulder anatomy and physiology compared to humans, and may represent a previously underutilized model for shoulder research. This study sought to identify naturally occurring bony and muscular degeneration in the shoulder of nonhuman primates and to assess relationships between structural and functional aspects of the shoulder and measures of physical function of the animals. We hypothesized that age-related degenerative changes in the shoulders of nonhuman primates would resemble those observed in aging humans. METHODS: Middle-aged (n = 5; ages 9.4-11.8 years) and elderly (n = 6; ages 19.8-26.4 years) female vervet monkeys were studied for changes in mobility and shoulder function, and radiographic and histologic signs of age-related degeneration. RESULTS: Four out of 6 (4/6) elderly animals had degenerative changes of the glenoid compared to 0/5 of the middle-aged animals (P = .005). Elderly animals had glenoid retroversion, decreased joint space, walked slower, and spent less time climbing and hanging than middle-aged vervets (P < .05). Physical mobility and shoulder function correlated with glenoid version angle (P < .05). Supraspinatus muscles of elderly animals were less dense (P = .001), had decreased fiber cross-sectional area (P < .001), but similar amounts of nuclear material (P = .085). Degenerative rotator cuff tears were not observed in any of the eleven animals. DISCUSSION AND CONCLUSION: The vervet monkey naturally undergoes age-related functional, radiographic and histological changes of the shoulder, and may qualify as an animal model for selected translational research of shoulder osteoarthritis.

The science of rotator cuff tears: translating animal models to clinical recommendations using simulation analysis.

PURPOSE: The purpose of this article is to review basic science studies using various animal models for rotator cuff research and to describe structural, biomechanical, and functional changes to muscle following rotator cuff tears. The use of computational simulations to translate the findings from animal models to human scale is further detailed. METHODS: A comprehensive review was performed of the basic science literature describing the use of animal models and simulation analysis to examine muscle function following rotator cuff injury and repair in the ageing population. RESULTS: The findings from various studies of rotator cuff pathology emphasize the importance of preventing permanent muscular changes with detrimental results. In vivo muscle function, electromyography, and passive muscle-tendon unit properties were studied before and after supraspinatus tenotomy in a rodent rotator cuff injury model (acute vs chronic). Then, a series of simulation experiments were conducted using a validated computational human musculoskeletal shoulder model to assess both passive and active tension of rotator cuff repairs based on surgical positioning. CONCLUSION: Outcomes of rotator cuff repair may be improved by earlier surgical intervention, with lower surgical repair tensions and fewer electromyographic neuromuscular changes. An integrated approach of animal experiments, computer simulation analyses, and clinical studies may allow us to gain a fundamental understanding of the underlying pathology and interpret the results for clinical translation.

Evaluation of in vivo rotator cuff muscle function after acute and chronic detachment of the supraspinatus tendon: an experimental study in an animal model.

BACKGROUND: Surgical repair of large chronic rotator cuff tears can be technically demanding because it requires manipulation of a muscle-tendon unit that is scarred, retracted, and stiffer than normal, all of which contribute to increased tension at the repair site. The purpose of the present study was to characterize the in vivo rotator cuff muscle-tendon unit function after acute and chronic injury at surgically relevant preload tensions. METHODS: Sixty-two Sprague-Dawley rats were divided into a healthy, uninjured (control) group (n = 22), an acute injury group (n = 20), and a chronic injury group (n = 20) and underwent in vivo muscle force testing and electromyographic testing of the supraspinatus muscle-tendon unit at various preload tensions. RESULTS: Preload tension affected the maximum supraspinatus muscle contractile force in all groups (p < 0.05). At the peak tension required to repair an acute tear, there was a 28% to 30% reduction in maximum tetanic contraction amplitude in all groups (p < 0.05). At the peak tension required to repair a chronic tear, there was a 40% to 53% reduction in maximal tetanic contraction amplitude in all groups (p < 0.05). The uninjured (control) group showed increased muscle endurance (p < 0.05) in comparison with the acute injury and chronic injury groups at all preload tensions. The chronic injury group showed reduced compound motor action potential amplitude (p < 0.05). CONCLUSIONS: Both the acute and chronic injury groups demonstrated functional impairment related to increasing preload tensions. Higher repair tensions, associated with the chronic injury setting, resulted in greater functional impairment. The present study also demonstrates an association between increased time from rotator cuff tendon injury and impaired in vivo rotator cuff muscle electromyographic findings.

Postural dependence of passive tension in the supraspinatus following rotator cuff repair: a simulation analysis.

BACKGROUND: Despite surgical advances, repair of rotator cuff tears is associated with 20-70% incidence of recurrent tearing. The tension required to repair the torn tendon influences surgical outcomes and may be dependent on the gap length from torn tendon that must be spanned by the repair. Detailed understanding of forces throughout the range of motion (ROM) may allow surgeons to make evidence-based recommendations for post-operative care. METHODS: We used a computational shoulder model to assess passive tension and total moment-generating capacity in supraspinatus for repairs of gaps up to 3 cm throughout the shoulder (ROM). FINDINGS: In 60° abduction, increased gap length from 0.5 cm to 3 cm caused increases in passive force from 3N to 58 N, consistent with those seen during clinical repair. For reduced abduction, passive forces increased substantially. For a 0.5 cm gap, tension throughout the ROM (elevation, plane of elevation, and rotation) is within reasonable limits, but larger gaps are associated with tensions that markedly exceed reported pull-out strength of sutures and anchors. Peak moment for a large 3 cm gap length was 5.09 Nm, a 53% reduction in moment-generating capacity compared to uninjured supraspinatus. INTERPRETATION: We conclude that shoulder posture is an important determinant of passive forces during rotator cuff repair surgery. Choosing postures that reduce forces intraoperatively to permit repair of larger gaps may lead to failure postoperatively when the shoulder is mobilized. For larger defects, loss of strength in supraspinatus may be substantial following repair even if retear is prevented.

Chemical denervation with botulinum neurotoxin a improves the surgical manipulation of the muscle-tendon unit: an experimental study in an animal model.

PURPOSE: The chemical denervation that results from botulinum neurotoxin A (BoNT-A) causes a temporary, reversible paresis that can result in easier surgical manipulation of the muscle-tendon unit in the context of tendon rupture and repair. The purpose of the study was to determine whether BoNT-A injections can be used to temporarily and reversibly modulate active and passive skeletal muscle properties. METHODS: Male CD1 mice weighing 40-50 g were divided into a 1-week postinjection group (n = 13: n = 5 saline and n = 8 BoNT-A) and a 2-week postinjection group (n = 17: n = 7 saline and n = 10 BoNT-A). The animals had in vivo muscle force testing and in vivo biomechanical evaluation. RESULTS: There was a substantial decline in the maximal single twitch amplitude (p < .05) and tetanic amplitude (p < .05) at one week and at 2 weeks after BoNT-A injection, when compared to saline-injected controls. BoNT-A injection significantly reduced the peak passive properties of the muscle-tendon unit as a function of displacement at one week (p < .05). Specifically, the stiffness of the BoNT-A injected muscle-tendon unit was 0.417 N/mm compared to the control saline injected group, which was 0.634 N/mm, a 35% reduction in stiffness (p < .05). CONCLUSIONS: Presurgical treatment with BoNT-A might improve the surgical manipulation of the muscle-tendon unit, thus improving surgical outcomes. The results implicate neural tone as a substantial contributor to the passive repair tension of the muscle-tendon unit. The modulation of neural tone through temporary, reversible paresis is a novel approach that might improve intraoperative and postoperative passive muscle properties, allowing for progressive rehabilitation while protecting the surgical repair site.

Hand and body radiation exposure with the use of mini C-arm fluoroscopy.

PURPOSE: To determine whole body and hand radiation exposure to the hand surgeon wearing a lead apron during routine intraoperative use of the mini C-arm fluoroscope. METHODS: Four surgeons (3 hand attending surgeons and 1 hand fellow) monitored their radiation exposure for a total of 200 consecutive cases (50 cases per surgeon) requiring mini C-arm fluoroscopy. Each surgeon measured radiation exposure with a badge dosimeter placed on the outside breast pocket of the lead apron (external whole body exposure), a second badge dosimeter under the lead apron (shielded whole body exposure), and a ring dosimeter (hand exposure). RESULTS: Completed records were noted in 198 cases, with an average fluoroscopy time of 133.52 seconds and average cumulative dose of 19,260 rem-cm(2) per case. The total measured radiation exposures for the (1) external whole body exposure dosimeters were 16 mrem (for shallow depth), 7 mrem (for eye depth), and less than 1 mrem (for deep depth); (2) shielded whole body badge dosimeters recorded less than 1 mrem; and (3) ring dosimeters totaled 170 mrem. The total radial exposure for 4 ring dosimeters that had registered a threshold of 30 mrem or more of radiation exposure was 170 mrem at the skin level, for an average of 42.5 mrem per dosimeter ring or 6.3 mrem per case. CONCLUSIONS: This study of whole body and hand radiation exposure from the mini C-arm includes the largest number of surgical cases in the published literature. The measured whole body and hand radiation exposure received by the hand surgeon from the mini C-arm represents a minimal risk of radiation, based on the current National Council on Radiation Protection and Management standards of annual dose limits (5,000 mrem per year for whole body and 50,000 mrem per year to the extremities).