Point-of-Care Ultrasound for Diagnosis and Pain Control of Sternal Fracture.

In this case report, point-of-care ultrasound (POCUS) was performed to diagnose a sternal fracture and to perform an ultrasound-guided hematoma block on an elderly patient through which excellent pain control was achieved. POCUS is a valuable tool in expediting the diagnosis of sternal fracture and can be used to safely perform a hematoma block for pain control.

Evolution of knowledge on meniscal biomechanics: a 40 year perspective.

BACKGROUND: Knowledge regarding the biomechanics of the meniscus has grown exponentially throughout the last four decades. Numerous studies have helped develop this knowledge, but these studies have varied widely in their approach to analyzing the meniscus. As one of the subcategories of mechanical phenomena Medical Subject Headings (MeSH) terms, mechanical stress was introduced in 1973. This study aims to provide an up-to-date chronological overview and highlights the evolutionary comprehension and understanding of meniscus biomechanics over the past forty years. METHODS: A literature review was conducted in April 2021 through PubMed. As a result, fifty-seven papers were chosen for this narrative review and divided into categories; Cadaveric, Finite element (FE) modeling, and Kinematic studies. RESULTS: Investigations in the 1970s and 1980s focused primarily on cadaveric biomechanics. These studies have generated the fundamental knowledge basis for the emergence of FE model studies in the 1990s. As FE model studies started to show comparable results to the gold standard cadaveric models in the 2000s, the need for understanding changes in tissue stress during various movements triggered the start of cadaveric and FE model studies on kinematics. CONCLUSION: This study focuses on a chronological examination of studies on meniscus biomechanics in order to introduce concepts, theories, methods, and developments achieved over the past 40 years and also to identify the likely direction for future research. The biomechanics of intact meniscus and various types of meniscal tears has been broadly studied. Nevertheless, the biomechanics of meniscal tears, meniscectomy, or repairs in the knee with other concurrent problems such as torn cruciate ligaments or genu-valgum or genu-varum have not been extensively studied.

The effect of surgeon-controlled variables on construct stiffness in lateral locked plating of distal femoral fractures.

BACKGROUND: Nonunion following treatment of supracondylar femur fractures with lateral locked plates (LLP) has been reported to be as high as 21 %. Implant related and surgeon-controlled variables have been postulated to contribute to nonunion by modulating fracture-fixation construct stiffness. The purpose of this study is to evaluate the effect of surgeon-controlled factors on stiffness when treating supracondylar femur fractures with LLPs: 1. Does plate length affect construct stiffness given the same plate material, fracture working length and type of screws? 2. Does screw type (bicortical locking versus bicortical nonlocking or unicortical locking) and number of screws affect construct stiffness given the same material, fracture working length, and plate length? 3. Does fracture working length affect construct stiffness given the same plate material, length and type of screws? 4. Does plate material (titanium versus stainless steel) affect construct stiffness given the same fracture working length, plate length, type and number of screws? METHODS: Mechanical study of simulated supracondylar femur fractures treated with LLPs of varying lengths, screw types, fractureworking lenghts, and plate/screw material. Overall construct stiffness was evaluated using an Instron hydraulic testing apparatus. RESULTS: Stiffness was 15 % higher comparing 13-hole to the 5-hole plates (995 N/mm849N vs. /mm, p = 0.003). The use of bicortical nonlocking screws decreased overall construct stiffness by 18 % compared to bicortical locking screws (808 N/mm vs. 995 N/mm, p = 0.0001). The type of screw (unicortical locking vs. bicortical locking) and the number of screws in the diaphysis (3 vs. 10) did not appear to significantly influence construct stiffness (p = 0.76, p = 0.24). Similarly, fracture working length (5.4 cm vs. 9.4 cm, p = 0.24), and implant type (titanium vs. stainless steel, p = 0.12) did also not appear to effect stiffness. DISCUSSION: Using shorter plates and using bicortical nonlocking screws (vs. bicortical locking screws) reduced overall construct stiffness. Using more screws, using unicortical locking screws, increasing fracture working length and varying plate material (titanium vs. stainless steel) does not appear to significantly alter construct stiffness. Surgeons can adjust plate length and screw types to affect overall fracture-fixation construct stiffness; however, the optimal stiffness to promote healing remains unknown.

Analgesic efficacy of morphine sulfate immediate release vs. oxycodone/acetaminophen for acute pain in the emergency department.

OBJECTIVE: Previous research demonstrated that administration of Morphine Sulfate Immediate Release (MSIR) results in similar analgesic efficacy to Oxycodone but with significantly lesser degrees of euphoria and reward. The purpose of this study sit to investigate if MSIR combined with Acetaminophen can serve as an opioid analgesic alternative to Oxycodone combined with acetaminophen (Percocet) for acute pain in the Emergency Department (ED). METHODS: A prospective, randomized, double-blind trial of ED patients aged 18 to 64 years presenting with moderate to severe acute pain as defined by an 11-point numeric rating scale (NRS) with an initial score of ≥5 (0 = no pain and 10 = very severe pain). Patients were randomized to receive either 15 mg MSIR combined with 650 mg of Acetaminophen or 10 mg Oxycodone combined with 650 mg Acetaminophen. Patients were assessed at baseline, 30, 45 and 60 min. The primary outcome was reduction in pain at 60 min. Secondary outcomes include drug likeability and adverse events. RESULTS: 80 patients were enrolled in the study (40 per group). Demographic characteristics were similar between the groups (P > 0.05). Mean NRS pain scores at baseline were 8.44 for the MSIR group and 8.53 for the Percocet group (P = 0.788). Mean pain scores decreased over time but remained similar between the groups: 30 min (6.03 vs. 6.43; P = 0.453), 45 min (5.31 vs. 5.48; P = 0.779), and 60 min (4.22 vs. 4.87; P = 0.346). Reduction in mean NRS pain scores were statistically significant from baseline to 30, 45 and 60 min within each group (P < 0.0001 at each time point for both groups). The largest NRS mean difference was from baseline to 60 min: 4.2 (95% CI: 3.43 to 5.01) for MSIR group and 3.61 (95% CI: 2.79 to 4.43) for Percocet group. No clinically significant changes or any serious adverse events were observed in either group. CONCLUSION: MSIR provides similar analgesic efficacy as Percocet for short-term pain relief in the ED, similar rates of nausea/vomiting, and lower rates of likeability of the drug.

Evaluation of musculoskeletal phenotype of the G608G progeria mouse model with lonafarnib, pravastatin, and zoledronic acid as treatment groups.

Hutchinson-Gilford progeria syndrome (HGPS) is a uniformly fatal condition that is especially prevalent in skin, cardiovascular, and musculoskeletal systems. A wide gap exists between our knowledge of the disease and a promising treatment or cure. The aim of this study was to first characterize the musculoskeletal phenotype of the homozygous G608G BAC-transgenic progeria mouse model, and to determine the phenotype changes of HGPS mice after a five-arm preclinical trial of different treatment combinations with lonafarnib, pravastatin, and zoledronic acid. Microcomputed tomography and CT-based rigidity analyses were performed to assess cortical and trabecular bone structure, density, and rigidity. Bones were loaded to failure with three-point bending to assess strength. Contrast-enhanced µCT imaging of mouse femurs was performed to measure glycosaminoglycan content, thickness, and volume of the femoral head articular cartilage. Advanced glycation end products were assessed with a fluorometric assay. The changes demonstrated in the cortical bone structure, rigidity, stiffness, and modulus of the HGPS G608G mouse model may increase the risk for bending and deformation, which could result in the skeletal dysplasia characteristic of HGPS. Cartilage abnormalities seen in this HGPS model resemble changes observed in the age-matched WT controls, including early loss of glycosaminoglycans, and decreased cartilage thickness and volume. Such changes might mimic prevalent degenerative joint diseases in the elderly. Lonafarnib monotherapy did not improve bone or cartilage parameters, but treatment combinations with pravastatin and zoledronic acid significantly improved bone structure and mechanical properties and cartilage structural parameters, which ameliorate the musculoskeletal phenotype of the disease.

Comparison of Oral Ibuprofen and Acetaminophen with Either Analgesic Alone for Pediatric Emergency Department Patients with Acute Pain.

BACKGROUND: Ibuprofen (Motrin; Johnson & Johnson) and acetaminophen (APAP, paracetamol) are the most commonly used analgesics in the pediatric emergency department (ED) for managing a variety of acute traumatic and nontraumatic painful conditions. The multimodal pain management of using a combination of ibuprofen plus acetaminophen has the potential to result in greater analgesia. OBJECTIVE: We compared the analgesic efficacy of a combination of oral ibuprofen plus acetaminophen with either analgesic alone for pediatric ED patients with acute pain. METHODS: We performed a randomized, double-blind superiority trial assessing and comparing the analgesic efficacy of a combination of oral ibuprofen (10 mg/kg dose) plus acetaminophen (15 mg/kg per dose) to either analgesic alone for the treatment of acute traumatic and nontraumatic pain in the pediatric ED. Primary outcomes included a difference in pain scores among the three groups at 60 min. RESULTS: We enrolled 90 patients (30 per group). The difference in mean pain scores at 60 min between acetaminophen and combination groups was 0.30 (95% confidence interval [CI] -0.84 to 1.83); between ibuprofen and combination groups was -0.33 (95% CI -1.47 to 0.80); and between acetaminophen and ibuprofen groups was 0.63 (95% CI -0.54 to 1.81). Reductions in pain scores from baseline to 60 min were similar for all patients in each of the three groups. No adverse events occurred in any group. CONCLUSIONS: We found similar analgesic efficacy of oral ibuprofen and acetaminophen in comparison with each analgesic alone for short-term treatment of acute pain in the pediatric ED, but the trial was underpowered to demonstrate the analgesic superiority of the combination of oral ibuprofen plus acetaminophen in comparison with each analgesic alone.

Administration of Nebulized Ketamine for Managing Acute Pain in the Emergency Department: A Case Series.

Ketamine administration in sub-dissociative doses in the emergency department (ED) results in effective pain relief in patients with acute traumatic and non-traumatic pain, chronic pain, and opioid-tolerant pain. This case series describes five adult ED patients who received nebulized ketamine for predominantly acute traumatic pain. Three patients received nebulized ketamine at 1.5 milligrams per kilogram (mg/kg) dose, one patient at 0.75 mg/kg, and one patient at 1 mg/kg. All five patients experienced a decrease in pain from the baseline up to 120 minutes. The inhalation route of ketamine delivery via breath-actuated nebulizer may have utility for managing pain in the ED.

Comparison of Oral Ibuprofen at Three Single-Dose Regimens for Treating Acute Pain in the Emergency Department: A Randomized Controlled Trial.

STUDY OBJECTIVE: Nonsteroidal anti-inflammatory drugs (NSAIDs) are used extensively for the management of acute pain, with ibuprofen being one of the most frequently used oral analgesics in the emergency department (ED). We compare the analgesic efficacy of oral ibuprofen at 3 different doses for adult ED patients with acute pain. METHODS: This was a randomized, double-blind trial comparing analgesic efficacy of 3 doses of oral ibuprofen (400, 600, and 800 mg) in adult ED patients with acute painful conditions. Primary outcome included difference in pain scores between the 3 groups at 60 minutes. RESULTS: We enrolled 225 subjects (75 per group). The difference in mean pain scores at 60 minutes between the 400- and 600-mg groups was -0.14 (95% confidence interval [CI] -0.67 to 0.39); between the 400- and 800-mg groups, 0.14 (95% CI -0.65 to 0.37); and between the 600- and 800-mg groups, 0.00 (95% CI -0.47 to 0.47). Reductions in pain scores from baseline to 60 minutes were similar for all subjects in each of the 3 groups. No adverse events occurred in any group. CONCLUSION: Oral ibuprofen administered at doses of 400, 600, and 800 mg has similar analgesic efficacy for short-term pain relief in adult patients presenting to the ED with acute pain.

Daytime Changes of Skin Biophysical Characteristics: A Study of Hydration, Transepidermal Water Loss, pH, Sebum, Elasticity, Erythema, and Color Index on Middle Eastern Skin.

BACKGROUND: The exposure of skin to ultraviolet radiation and temperature differs significantly during the day. It is reasonable that biophysical parameters of human skin have periodic daily fluctuation. The objective of this study was to study the fluctuations of various biophysical characteristics of Middle Eastern skin in standardized experimental conditions. MATERIALS AND METHODS: Seven biophysical parameters of skin including stratum corneum hydration, transepidermal water loss, pH, sebum, elasticity, skin color, and erythema index were measured at three time points (8 a.m., 12 p.m. and 4 p.m.) on the forearm of 12 healthy participants (mean age of 28.4 years) without any ongoing skin disease using the CK MPA 580 device in standard temperature and humidity conditions. RESULTS: A significant difference was observed between means of skin color index at 8 a.m. (175.42 ± 13.92) and 4 p.m. (164.44 ± 13.72, P = 0.025), between the pH at 8 a.m. (5.72 ± 0.48) and 4 p.m. (5.33 ± 0.55, P = 0.001) and pH at 12 p.m. (5.60 ± 0.48) and 4 p.m. (5.33 ± 0.55, P = 0.001). Other comparisons between the means of these parameters at different time points resulted in nonsignificant P values. CONCLUSION: There are daytime changes in skin color index and pH. Skin color index might be higher and cutaneous pH more basic in the early morning compared to later of the day.

Posterior Capsular Plication Constrains the Glenohumeral Joint by Drawing the Humeral Head Closer to the Glenoid and Resisting Abduction.

BACKGROUND: Shoulder pain is a common problem, with 30% to 50% of the American population affected annually. While the majority of these shoulder problems improve, there is a high rate of recurrence, as 54% of patients experience persistent symptoms 3 years after onset. PURPOSE: Posterior shoulder tightness has been shown to alter glenohumeral (GH) kinematics. Clinically, posterior shoulder contractures result in a significant loss of internal rotation and abduction (ABD). In this study, the effect of a posterior capsular contracture on GH kinematics was investigated using an intact cadaveric shoulder without violating the joint capsule or the rotator cuff. STUDY DESIGN: Controlled laboratory study. METHODS: Glenohumeral motion, humeral load, and subacromial contact pressure were measured in 6 fresh-frozen left shoulders during passive ABD from 60° to 100° using an automated robotic upper extremity testing system. Baseline values were compared with the experimental condition in which the full thickness of posterior tissues was plicated without decompressing the joint capsule. RESULTS: Posterior soft tissue plication resulted in increased compression between the humeral head and the glenoid (axial load) at 90° of ABD. Throughout ABD, the posterior contracture increased the anterior and superior moment on the humeral head, but it did not change the GH kinematics in this intact model. As a result, there was no increase in the subacromial contact pressure during ABD with posterior plication. CONCLUSION: In an intact cadaveric shoulder, posterior contracture does not alter GH motion or subacromial contact pressure during passive ABD. By tightening the soft tissue envelope posteriorly, there is an increase in compressive load on the articular cartilage and anterior/superior force on the humeral head. These findings suggest that subacromial impingement in the setting of a posterior soft tissue contracture may result from alterations in scapulothoracic motion, not changes in GH kinematics. CLINICAL RELEVANCE: This investigation demonstrates that posterior capsular plication increases the axial load on the shoulder joint during ABD. While a significant difference from baseline was observed in the plicated condition, posterior capsular plication did not change GH motion or subacromial contact pressure significantly.

Methodology to Calibrate Disc Degeneration in the Cervical Spine During Cyclic Fatigue Loading.

Prolonged exposure to vibrational working conditions can cause neck, back, and shoulder pain. Mechanical degradation of soft tissues resulting from this type of fatigue was experimentally shown to contribute to endplate and compression fractures. However, effects of repetitive subfailure loading on intervertebral disc (IVD) behavior have not been well defined. This manuscript describes a methodology to experimentally characterize changes in cervical spine IVD material properties under fatigue. Bone-disc-bone spinal units with intact ligaments obtained from human cervical spines were obtained and a lack of bony or soft tissue degeneration was confirmed using X-ray and MRI scans. Cranial and caudal specimen extents were fixed in PMMA to facilitate attachment to testing devices. Baseline response was quantified using flexion/extension pure moment protocols. Specimens were immersed in a 34-deg-C saline bath and allowed to acclimate for one hour. A stress-relaxation test was then performed and viscoelasticity quantified using a quasi linear viscoelastic (QLV) material model. Fatigue testing was performed for up to 50,000 cycles with intermittent viscoelasticity, pure moment testing, and imaging scans performed to quantify cycle-dependent changes in disc properties. Preliminary results demonstrated progressive changes in viscoelasticity and bending response of cervical spine segments with increasing number of load cycles. This procedure will be used to quantify degradation of the IVD under repetitive compressive loads, focusing on effects of loading magnitude and frequency.

Analysis of a new all-inside versus inside-out technique for repairing radial meniscal tears.

PURPOSE: The purpose of this study was to compare gap formation, strength, and stiffness of repaired radial tears of the meniscus treated using a new all-inside technique versus a traditional inside-out suture technique. METHODS: Radial tears were created in 36 fresh-frozen porcine menisci. Repairs were performed using a novel all-inside suture-based meniscal repair device or an inside-out technique. The repairs were tested for cyclic loading and load to failure. The displacement, response to cyclic loading (100, 300, and 500 cycles), and mode of failure were recorded, and the construct's stiffness was calculated. RESULTS: The all-inside repairs using the novel device resulted in a significantly lower displacement (gap formation) after 100, 300, and 500 cycles (P = .002, P = .001, and P = .001, respectively). The ultimate load to failure was significantly greater for the all-inside repairs (111.61 N v 95.01 N; P = .03). The all-inside repairs showed greater stiffness (14.53 N/mm v 11.19 N/mm; P = .02). The all-inside repairs failed most often by suture breakage (suture failure). The inside-out repairs failed most commonly when the suture pulled through the tissue (tissue failure) (P < .001). CONCLUSIONS: For repair of radial tears of the meniscus, the vertical suture configuration created by the all-inside technique resulted in lower displacement, higher load to failure, and greater stiffness compared with the horizontal inside-out technique. CLINICAL RELEVANCE: In a porcine specimen meniscus repair model, the biomechanical properties of a vertical all-inside technique were superior to that of a horizontal inside-out technique. Future studies of biomechanical and clinical outcomes in human meniscal repairs with this device are warranted to explore whether this repair method is valuable to clinical practice and patient outcomes.

Biomechanical evaluation of an all-inside suture-based device for repairing longitudinal meniscal tears.

PURPOSE: A device for all-inside suture-based meniscal repairs has been introduced (NovoStitch; Ceterix, Menlo Park, CA) that passes the suture vertically through the meniscus, thereby encircling the tear, and does not require an additional incision or extra-capsular anchors. Our aim was to compare this all-inside suture-based repair with an inside-out suture repair and an all-inside anchor-based repair (FasT-Fix 360°; Smith & Nephew, Andover, MA). METHODS: Longitudinal tears were created in 36 fresh-frozen porcine menisci. Repairs were performed using an all-inside suture-based meniscal repair device, an all-inside anchor-based repair, and an inside-out suture repair. They were tested with cyclic loading and load-to-failure testing. The displacement, response to cyclic loading (100, 300, and 500 cycles), and mode of failure were recorded. The stiffness of the constructs was calculated as well. RESULTS: The all-inside suture-based repairs and the inside-out repairs showed significantly higher loads to failure than the all-inside anchor-based repairs. The stiffness values for the 3 repairs were not different. There were no differences in initial displacement. After 100, 300, and 500 cycles, the inside-out repair had higher gap formation (displacement) than the other 2 groups. Suture failure was the predominant mode of failure across all repair techniques. CONCLUSIONS: The all-inside suture-based repairs and inside-out repairs did not exhibit different load-to-failure values. In addition, the all-inside suture-based repairs and the all-inside anchor-based repairs did not exhibit different displacement values during cyclic loading. CLINICAL RELEVANCE: When addressing a longitudinal meniscal tear, surgeons should consider biomechanical data of various repair devices and techniques in their decision-making process to maximize the mechanical strength and healing probability of the repair.

Sensitivity and stability analysis of a nonlinear material model of cervical intervertebral disc under cyclic loads using the finite element method.

It is known that the human spine exhibits non-linear behavior, and its intervertebral discs play a role in the mechanism of internal load transfer. It is important to simulate its nonlinear behavior in computational models for better delineation of intrinsic responses, especially during cyclic loading activities, a mode pertinent to civilian and military populations. For developing a robust “material model” of the disc, this study used experimental tensile-compressive cyclic loading responses from four human cadaver cervical functional spinal units. Disc deformations were measured using an ultrasound system at 42 samples per second. Using experimental data, a three-network non-linear “material model” was developed using an optimization procedure and finite-element analysis. The model used 12 parameters to capture loading and unloading in tension and compression, including hysteresis. A sensitivity analysis performed to test the robustness of the “material model” indicated that seven of the 12 parameters were sensitive to tension, compressive, or both loading modes. Stability analysis was also performed under nine different loading conditions. The developed “material model” is robust and stable to capture intervertebral disc responses in tensile-compressive cyclic loading and can be used in future finite-element models.

Finite element analysis and computed tomography based structural rigidity analysis of rat tibia with simulated lytic defects.

Finite element analysis (FEA), CT based structural rigidity analysis (CTRA) and mechanical testing is performed to assess the compressive failure load of rat tibia with simulated lytic defects. Twenty rat tibia were randomly assigned to four equal groups (n=5). Three of the groups included a simulated defect at various locations: anterior bone surface (Group 1), posterior bone surface (Group 2) and through bone defect (Group 3). The fourth group was a control group with no defect (Group 4). Microcomputed tomography was used to assess bone structural rigidity properties and to provide 3D model data for generation of the finite element models for each specimen. Compressive failure load calculated using CT derived rigidity parameters (FCTRA) was well correlated to failure load recorded in mechanical testing (R(2)=0.96). The relationships between mechanical testing failure load and the axial rigidity (R(2)=0.61), bending rigidity (R(2)=0.71) and FEA calculated failure loads, considering bone as an elastic isotropic (R(2)=0.75) and elastic transversely isotropic (R(2)=0.90) are also well correlated. CTRA stress, calculated adjacent to the defect, were also shown to be well correlated with yield stresses calculated using the minimum density at the weakest cross section (R(2)=0.72). No statistically significant relationship between apparent density and mechanical testing failure load was found (P=0.37). In summary, the results of this study indicate that CTRA analysis of bone strength correlates well with both FEA and results obtained from compression experiments. In addition there exist a good correlation between structural rigidity parameters and experimental failure loads. In contrast, there was no correlation between average bone density and failure load.