Comparison of erector spinae and gluteus medius muscle thickness and activation in individuals with and without low back pain.

BACKGROUND: Dysfunctional patterns of the erector spinae (ES) and gluteus medius (GM) muscles often accompany episodes of low back pain (LBP). Rehabilitative ultrasound imaging (RUSI) has been used to measure ES and GM muscle thickness, however such measurements have not been compared in individuals with and without LBP. OBJECTIVES: To compare ES and GM muscle thickness and change in thickness utilizing RUSI in individuals with and without LBP. DESIGN: Cross-sectional comparison. METHODS: A volunteer sample of 60 adults with (n = 30) and without (n = 30) LBP was examined. Thickness measurements of the ES and GM at rest and during contraction were obtained by using RUSI during a single session. Statistical comparison was performed using ANCOVA. The demographic variable age was used as a covariate in the primary comparative analysis. RESULTS: Mean difference for age between groups was 5.4 years (95% CI: 1.85, 8.94, p = 0.004). Average ODI score was 32.33±6.58 and pain level of 5.39±0.73 over the last 24 h in the symptomatic group. There was a statistically significant difference in the percent thickness change in both the ES, mean difference = -3.46 (95% CI: -6.71, -0.21, p = 0.039) and GM, mean difference = -1.93 (95% CI: -3.85, -0.01, p = 0.049) muscles between groups. CONCLUSIONS: Individuals with LBP may have reduced percent thickness change of the ES and GM muscles when compared to asymptomatic individuals.

Physically Active Adults with Low Back Pain do not Demonstrate Altered Deadlift Mechanics: A Novel Application of Myotonometry to Estimate Inter-Muscular Load Sharing.

Background: Rehabilitation clinicians that work with physically active populations are challenged with how to safely return patients back to performing deadlift movements following low back injury. Application of reliable and valid tests and measures to quantify impairments related to low back pain (LBP) enhances clinical decision making and may affect outcomes. Myotonometry is a non-invasive method to assess muscle stiffness which has demonstrated significant associations with physical performance and musculoskeletal injury. Hypothesis/Purpose: The purpose of this study was to compare the stiffness of trunk (lumbar multifidus [LM] and longissimus thoracis [LT]) and lower extremity (vastus lateralis [VL] and biceps femoris [BF]) muscles between individuals with and without LBP during the lying, standing, and deadlifting body positions. Study Design: Cross-sectional cohort comparison. Methods: Muscle stiffness measures were collected in the VL, BF, LM, and LT muscles with participants in lying (supine and prone), standing, and the trap bar deadlift position. Separate analyses of covariance were conducted to compare absolute and relative muscle stiffness between the groups for each muscle and condition. Results: Sixty-eight participants (41 female, 21.3 years, 34 LBP) volunteered for the study. Within the deadlift condition there was a significantly greater increase in the percent-muscle stiffness change in the VL (p = .029, 21.9%) and BF (p = .024, 11.2%) muscles in the control group than in the LBP group. There were no differences in percent-muscle stiffness changes for the standing condition nor were there any absolute muscle stiffness differences between the two groups for the three conditions. Conclusion: No differences in muscle stiffness were identified in the lying, standing, or deadlifting conditions between participants with and without LBP. Differences in percent stiffness changes were noted between groups for the deadlift position, however the differences were modest and within measurement error. Future studies should investigate the utility of myotonometry as a method to identify LBP-related impairments that contribute to chronic and/or recurrent low back injury. Level of Evidence: Level 3.

Myotonometry is Capable of Reliably Obtaining Trunk and Thigh Muscle Stiffness Measures in Military Cadets During Standing and Squatting Postures.

INTRODUCTION: Low back and lower extremity injuries are responsible for the highest percentage of musculoskeletal injuries in U.S. Army soldiers. Execution of common soldier tasks as well as army combat fitness test events such as the three-repetition maximum deadlift depends on healthy functioning trunk and lower extremity musculature to minimize the risk of injury. To assist with appropriate return to duty decisions following an injury, reliable and valid tests and measures must be applied by military health care providers. Myotonometry is a noninvasive method to assess muscle stiffness, which has demonstrated significant associations with physical performance and musculoskeletal injury. The aim of this study is to determine the test-retest reliability of myotonometry in lumbar spine and thigh musculature across postures (standing and squatting) that are relevant to common soldier tasks and the maximum deadlift. MATERIALS AND METHODS: Repeat muscle stiffness measures were collected in 30 Baylor University Army Cadets with 1 week between each measurement. Measures were collected in the vastus lateralis (VL), biceps femoris (BF), lumbar multifidus (LM), and longissimus thoracis (LT) muscles with participants in standing and squatting positions. Intraclass correlation coefficients (ICCs3,2) were estimated, and their 95% CIs were calculated based on a mean rating, mixed-effects model. RESULTS: The test-retest reliability (ICC3,2) of the stiffness measures was good to excellent in all muscles across the standing position (ICCs: VL = 0.94 [0.87-0.97], BF = 0.97 [0.93-0.98], LM = 0.96 [0.91-0.98], LT = 0.81 [0.59-0.91]) and was excellent in all muscles across the squatting position (ICCs: VL = 0.95 [0.89-0.98], BF = 0.94 [0.87-0.97], LM = 0.96 [0.92-0.98], LT = 0.93 [0.86-0.97]). CONCLUSION: Myotonometry can reliably acquire stiffness measures in trunk and lower extremity muscles of healthy individuals in standing and squatting postures. These results may expand the research and clinical applications of myotonometry to identify muscular deficits and track intervention effectiveness. Myotonometry should be used in future studies to investigate muscle stiffness in these body positions in populations with musculoskeletal injuries and in research investigating the performance and rehabilitative intervention effectiveness.

Beyond yellow flags: The Big-Five personality traits and psychologically informed musculoskeletal rehabilitation.

BACKGROUND: Psychosocial variables are known to play an important role in musculoskeletal pain. Recent efforts incorporating psychological theory into rehabilitative medicine, as part of patient-centred care or psychologically informed physical therapy, have gained broader acceptance. The fear-avoidance model is the dominant psychosocial model and has introduced a variety of phenomena which assess psychological distress (i.e., yellow flags). Yellow flags, such as fear, anxiety and catastrophizing, are useful concepts for musculoskeletal providers but reflect a narrow range of psychological responses to pain. OBJECTIVE: Clinicians lack a more comprehensive framework to understand psychological profiles of each patient and provide individualised care. This narrative review presents the case for applying personality psychology and the Big-Five trait model (extraversion, agreeableness, conscientiousness, neuroticism and openness to experience) to musculoskeletal medicine. These traits have strong associations with various health outcomes and provide a robust framework to understand patient emotion, motivation, cognition and behaviour. KEY RESULTS: High conscientiousness is associated with positive health outcomes and health promoting behaviours. High neuroticism with low conscientiousness increases the odds of negative health outcomes. Extraversion, agreeableness and openness have less direct effects but have positive correlations with important health behaviours, including active coping, positive affect, rehabilitation compliance, social connection and education level. CLINICAL APPLICATION: The Big-Five model offers an evidence-based way for MSK providers to better understand the personality of their patients and how it relates to health. These traits offer the potential for additional prognostic factors, tailored treatments and psychological intervention.

The Utility of Myotonometry in Musculoskeletal Rehabilitation and Human Performance Programming.

Myotonometry is a relatively novel method used to quantify the biomechanical and viscoelastic properties (stiffness, compliance, tone, elasticity, creep, and mechanical relaxation) of palpable musculotendinous structures with portable mechanical devices called myotonometers. Myotonometers obtain these measures by recording the magnitude of radial tissue deformation that occurs in response to the amount of force that is perpendicularly applied to the tissue through a device's probe. Myotonometric parameters such as stiffness and compliance have repeatedly demonstrated strong correlations with force production and muscle activation. Paradoxically, individual muscle stiffness measures have been associated with both superior athletic performance and a higher incidence of injury. This indicates optimal stiffness levels may promote athletic performance, whereas too much or too little may lead to an increased risk of injury. Authors of numerous studies suggested that myotonometry may assist practitioners in the development of performance and rehabilitation programs that improve athletic performance, mitigate injury risk, guide therapeutic interventions, and optimize return-to-activity decision-making. Thus, the purpose of our narrative review was to summarize the potential utility of myotonometry as a clinical tool that assists musculoskeletal clinicians with the diagnosis, rehabilitation, and prevention of athletic injuries.

Immediate Effects of Adding Dry Needling to Thoracic Manipulation and Exercise in Cervical Range of Motion for Adults With Neck Pain: A Randomized Clinical Trial.

OBJECTIVE: The purpose of this study was to determine the immediate effects of adding dry needling (DN) to thoracic spine manipulation and neck-specific exercise in individuals with neck pain. METHODS: Forty-two participants with neck pain were randomized to either the true (n = 21) or sham (n = 21) DN groups, receiving treatment on the initial visit and 2 to 3 days later. Outcomes were assessed on day 1, both at baseline and immediately after the initial treatment, at the second treatment 2 to 3 days later, and at the final visit 5 to 7 days after visit 2. Primary outcomes were Neck Disability Index (NDI) (0-50) and current pain via numeric pain rating scale (0-10). Secondary outcomes were cervical range of motion, pain pressure threshold, and global rating of change. RESULTS: Repeated measures analysis of covariance with baseline value as covariate revealed no significant difference in NDI scores at either follow-up time point with adjusted mean differences (95% confidence interval) of -0.11 (-2.70 to 2.48) and 0.31 (-1.96 to 2.57). There were no between-group differences in pain at any time point via Independent-Samples Median Test (P value range of .54-1.0). Secondary outcome measures were similarly not statistically different between groups except for immediate improvements in rotation to the side opposite of pain, which favored DN, with an adjusted mean difference (95% confidence interval) of 7.85 (3.54-12.15) degrees. CONCLUSION: The addition of DN to thoracic spinal manipulation and neck-specific exercise did not affect improvements in NDI score or numeric pain rating scale but showed an increase in cervical range of motion.

The validity of the cervical rotation lateral flexion test in predicting benefit after manipulation treatment to the first and second rib.

STUDY DESIGN: Prospective cohort study. BACKGROUND: The cervical rotation lateral flexion (CRLF) test is frequently used in clinical practice to determine whether a thrust manipulation targeting the first rib should be performed. OBJECTIVES: To evaluate the predictive validity of the CRLF test and manual examination in determining whether patients with neck pain are likely to benefit from manipulative treatment to the first and second rib. METHODS: A physical examination incorporating the CRLF test was performed on 50 participants with neck pain followed by manipulation treatment to the first and second ribs. Clinical improvement was assessed immediately and one week after treatment. Participants who experienced at least a 30% improvement in their Neck Disability Index (NDI) score were considered "improved." Predictive validity was assessed by calculating sensitivity, specificity, and negative and positive likelihood ratios. RESULTS: Neither the CRLF test nor manual examination were predictive of clinical improvement after manipulative treatment to the first and second rib. However, being male, of older age, and exhibiting T1 and/or T2 restricted end-feel were associated with improved neck related-disability at one-week follow-up. CONCLUSION: The CRLF test does not appear to be helpful in determining whether patients with neck pain are likely to benefit from manipulative treatment to the first and second rib. Other factors from the history and clinical examination may be more helpful when selecting manipulative treatment including age and gender and possibly the presence of T1/T2 restricted end-feel.

The Utility of Myotonometry in Musculoskeletal Rehabilitation and Human Performance Programming.

Myotonometry is a relatively novel method used to quantify the biomechanical and viscoelastic properties (stiffness, compliance, tone, elasticity, creep, mechanical relaxation) of palpable musculotendinous structures with portable mechanical devices called myotonometers. Myotonometers obtain these measures by recording the magnitude of radial tissue deformation that occurs in response to the amount of force that is perpendicularly applied to the tissue through a device's probe. Myotonometric parameters such as stiffness and compliance have repeatedly demonstrated strong correlations with force production and muscle activation. Paradoxically, individual muscle stiffness measures have been associated with both superior athletic performance and higher incidence of injury. This suggest there may be optimal stiffness levels that promotes athletic performance while too much or too little may lead to an increased risk of injury. Numerous studies suggest that myotonometry may assist practitioners in the development of performance and rehabilitation programs that improves athletic performance, mitigates injury risk, guides therapeutic interventions, and optimizes return to activity decision making. Thus, the purpose of this narrative review is to summarize the potential utility of myotonometry as a clinical tool that assists musculoskeletal clinicians with the diagnosis, rehabilitation, and prevention of athletic injuries.

The posterior/medial dry needling approach of the tibialis posterior muscle is an accurate and safe procedure: a cadaveric study.

BACKGROUND: Evidence suggests that tibialis posterior muscle plays an important role in equinovarus foot deformity in patients who had suffered a stroke and it is one of the most frequently injected lower-extremity muscles for the management of spasticity. Our aim was to assess if a needle accurately and safely penetrates the tibialis posterior muscle during the application of dry needling.  METHODS : We conducted a cadaveric descriptive study. Needling insertion of the tibialis posterior was conducted in 11 cryopreserved cadavers with a 70 mm needle. The needle was inserted using two common approaches, at midpoint (posterior/medial approach) and at upper third (anterior approach) of the leg towards the tibialis posterior. The needle was advanced into the tibialis posterior based upon clinician judgement. Cross-sectional anatomical dissections were photographed and analyzed by photometry. Safety was assessed by calculating the distances from the tip and the path of the needle to proximate neurovascular structures. RESULTS: Accurate needle penetration of the tibialis posterior muscle was observed in all cadavers with both approaches. In general, distances from the needle to the neurovascular bundles were larger with the posterior/medial approach than with the anterior approach, reaching statistically significance for needle tip to nerve (mean difference: 0.6 cm, 95%CI 0.35 to 0.85 cm) and vascular bundle (mean difference: 0.55 cm, 95%CI 0.3 to 0.8 cm) distances (P < 0.001) and needle path to vascular bundle distance (difference: 0.25 cm, 95%CI 0.1 to 0.4 cm, P = 0.045). Age and gender did not influence the main results. CONCLUSIONS: This cadaveric study suggests that needling of the tibialis posterior muscle can be accurately and safely conducted. Safety seems to be larger with the posterior/medial approach when compared with the anterior approach.

Effect of dry needling on lumbar muscle stiffness in patients with low back pain: A double blind, randomized controlled trial using shear wave elastography.

BACKGROUND: Dry needling treatment focuses on restoring normal muscle function in patients with musculoskeletal pain; however, little research has investigated this assertion. Shear wave elastography (SWE) allows quantification of individual muscle function by estimating both resting and contracted muscle stiffness. OBJECTIVE: To compare the effects of dry needling to sham dry needling on lumbar muscle stiffness in individuals with low back pain (LBP) using SWE. METHODS: Sixty participants with LBP were randomly allocated to receive one session of dry needling or sham dry needling treatment to the lumbar multifidus and erector spinae muscles on the most painful side and spinal level. Stiffness (shear modulus) of the lumbar multifidus and erector spinae muscles was assessed using SWE at rest and during submaximal contraction before treatment, immediately after treatment, and 1 week later. Treatment effects were estimated using linear mixed models. RESULTS: After 1 week, resting erector spinae muscle stiffness was lower in individuals who received dry needling than those that received sham dry needling. All other between-groups differences in muscle stiffness were similar, but non-significant. CONCLUSION: Dry needling appears to reduce resting erector spinae muscle following treatment of patients with LBP. Therefore, providers should consider the use of dry needling when patients exhibit aberrant stiffness of the lumbar muscles.

Does Engaging Patients with Relevant Education About Long-Term Opioid Use Before Spine Surgery Affect Long-term Opioid Use? A Randomized Controlled Trial.

STUDY DESIGN: Parallel-arm randomized controlled trial. OBJECTIVE: To assess the effectiveness of an enhanced video education session highlighting risks of opioid utilization on longterm opioid utilization after spine surgery. SUMMARY OF BACKGROUND DATA: Long-term opioid use occurs in more than half of patients undergoing spine surgery and strategies to reduce this use are needed. METHODS: Patients undergoing spine surgery at Brooke Army Medical Center between July 2015 and February 2017 were recruited at their preoperative appointment, receiving the singlesession interactive video education or control at that same appointment. Opioid utilization was tracked for the full year after surgery from the Pharmacy Data Transaction Service of the Military Health System Data Repository. Self-reported pain also collected weekly for 1 and at 6months. RESULTS: A total of 120 participants (40 women, 33.3%) with a mean age of 45.9 ±â€Š10.6 years were randomized 1:1 to the enhanced education and usual care control (60 per group). In the year following surgery the cohort had a mean 5.1 (standard deviation [SD] 5.9) unique prescription fills, mean total days' supply was 88.3 (SD 134.9), and mean cumulative morphine milligrams equivalents per participant was 4193.0 (SD 12,187.9) within the year after surgery, with no significant differences in any opioid use measures between groups. Twelve individuals in the standard care group and 13 in the enhanced education group were classified with having long-term opioid utilization. CONCLUSION: The video education session did not influence opioid use after spine surgery compared to the usual care control. There was no significant difference in individuals classified as long-term opioid users after surgery based on the intervention group. Prior opioid use was a strong predictor of future opioid use in this cohort. Strategies to improve education engagement, understanding, and decision- making continue to be of high importance for mitigating risk of long-term opioid use after spine surgery.Level of Evidence: 1.

Ultrasonographic Validation for Needle Placement in the Tibialis Posterior Muscle.

BACKGROUND: The tibialis posterior (TP) muscle plays an important role in normal foot function. Safe, efficacious therapeutic approaches addressing this muscle are necessary; however, the location of the muscle in the deep posterior compartment can create challenges. PURPOSE: The purpose of this study was to assess the accuracy of needle placement in the TP muscle and determine the needle placement in relation to the neurovascular structures located within the deep compartment. DESIGN: Cross Sectional Study. METHODS: Needle placement and ultrasound imaging were performed on 20 healthy individuals. A 50 mm or 60 mm needle was inserted between 30 - 50% of the tibial length measured from the medial tibiofemoral joint. The needle was inserted in a medial to lateral direction into the right extremity with the patient in right side lying. Placement of the needle into the TP muscle was verified with ultrasound imaging, and the shortest distance from the needle to the posterior tibial artery and tibial nerve was measured. The depth from the skin to the superficial border of the TP muscle was also measured. RESULTS: Ultrasonography confirmed the needle filament was inserted into the TP muscle in all 20 individuals and did not penetrate the neurovascular bundle in any individual. The mean distance from the needle to the tibial nerve and posterior tibial artery was 10.0 + 4.7 mm and 10.2 + 4.7 mm respectively. The superficial border of the TP muscle from the skin was at a mean depth of 25.8 + 4.9 mm. CONCLUSION: This ultrasound imaging needle placement study supports placement of a solid filament needle into the TP muscle with avoidance of the neurovascular structures of the deep posterior compartment when placed from a medial to lateral direction at 30-50% of the tibial length. LEVEL OF EVIDENCE: 2b.

Reliability and discriminative validity of real-time ultrasound elastography in the assessment of tissue stiffness after calf muscle injury.

OBJECTIVE: To investigate the reliability and discriminative validity of real-time ultrasound elastography (RTE) measures of soft-tissue elasticity after calf muscle tear. DESIGN: Cross-sectional, intra/inter-examiner reliability and comparative validity study. SETTING: Department of Physical Therapy. PARTICIPANTS: Twenty-one recreational athletes were included and examined 6 weeks after sustaining a grade I-II calf musculature tear. MAIN OUTCOME MEASURES: Soft-tissue elasticity was measured by two experienced assessors using RTE assessments in both the longitudinal and transverse planes of the athletes' injured and uninjured calf muscles. Elasticity was estimated by using the strain ratio (SR), which was calculated by dividing the strain (displacement) value taken at the medial gastrocnemius-soleus myotendinous junction (reference) by the strain value taken at the centre of the injury (index) as visualized on B-mode sonogram. Intra- and inter-observer reliability was estimated calculating intra-class correlation coefficients (ICCs) and standard error of measurement (SEM). Differences in elasticity between injured and healthy legs were assessed using t-tests or Wilcoxon tests for repeated measures. RESULTS: All RTE assessments in both planes showed ICC values ranging from 0.77 to 0.95 and SEM values ranging from 0.72 to 0.99. Additionally, RTE enabled both assessors to determine differences in elastic properties between injured and control legs (p < 0.001). CONCLUSION: RTE measures of calf muscles demonstrated good reliability and were able to differentiate injured from non-injured muscle tissue. RTE may provide a fast and objective measure in sports medicine to improve the detection of risk factors for muscle injury related to alterations of the mechanical behaviour of soft tissues during healing process.

Immediate decrease of muscle biomechanical stiffness following dry needling in asymptomatic participants.

BACKGROUND: Biomechanical muscle stiffness has been linked to musculoskeletal disorders. Assessing changes in muscle stiffness following DN may help elucidate a physiologic mechanism of DN. This study characterizes the effects of dry needling (DN) to the infraspinatus, erector spinae, and gastrocnemius muscles on biomechanical muscle stiffness. METHOD: 60 healthy participants were randomized into infraspinatus, erector spinae, or gastrocnemius groups. One session of DN was applied to the muscle in standardized location. Stiffness was assessed using a MyotonPRO at baseline, immediately post DN, and 24 h later. The presence of a localized twitch response (LTR) during DN was used to subgroup participants. RESULTS: A statistically significant decrease in stiffness was observed in the gastrocnemius, the LTR gastrocnemius, and the LTR erector spinae group immediately following DN treatment. However, stiffness increased after 24 h. No significant change was found in the infraspinatus group. CONCLUSIONS: DN may cause an immediate, yet transitory change in local muscle stiffness. It is unknown whether these effects are present in a symptomatic population or related to improvements in clinical outcomes. Future studies are necessary to determine if a decrease in biomechanical stiffness is related to improvement in symptomatic individuals.

Accuracy and safety of dry needling placement in the popliteus muscle: A cadaveric study.

BACKGROUND: The popliteus muscle attaches posteriorly to the joint capsule of the knee. Although it is an important rotational stabiliser and has been implicated in various knee pathologies, research on its treatment with dry needling is scarce. OBJECTIVE: To determine if a needle accurately and safely penetrates the popliteus muscle during the clinical application of dry needling. METHODS: A cadaveric descriptive study was conducted. Needling insertion of the popliteus muscle was conducted in 11 cryopreserved cadavers with a 50-mm needle. The needle was inserted at upper third of the posterior part of the tibia closest to the knee towards the popliteus. The needle was advanced into the muscle based upon clinician judgement. Cross-sectional anatomical dissections were photographed and analysed by photometry. Safety of the intervention was assessed by calculating the distance from the tip of the needle to the proximate neurovascular structures. RESULTS: Accurate needle penetration of the popliteus muscle was observed in 10 out of 11 (91%) of the cadavers (mean needle penetration: 25.7 ± 6.7mm, 95% CI 21.3-30.3 mm). The distances from the tip of the needle were 17±6mm (95% CI 13-21 mm) to the tibial nerve and 15 ± 0.7mm (95% CI 10-20 mm) to the popliteus vascular bundle. CONCLUSION: The results from this cadaveric study support the notion that needling of the popliteus can be accurately and safely conducted by an experienced clinician. Future studies investigating the clinical effectiveness of these interventions are needed.

The effects of dry needling to the thoracolumbar junction multifidi on measures of regional and remote flexibility and pain sensitivity: A randomized controlled trial.

BACKGROUND: Dry needling (DN) has been consistently shown to decrease pain sensitivity and increase flexibility local to the site of treatment, however it is unclear whether these effects are limited to the region of treatment or can be observed remote to the area of treatment. OBJECTIVE: To determine the immediate, short-term effects of DN to the thoracolumbar junction on regional and remote flexibility, and to observe if changes in pain sensitivity can occur remote to site of treatment. DESIGN: Double-blind randomized clinical trial. METHODS: Fifty-four subjects with low back pain and decreased length in at least one hamstring were randomized to receive either DN or sham DN to the T12 and L1 multifidi. Participants underwent regional (fingertip-to-floor) and remote flexibility (passive knee extension, passive straight leg raise) and pressure pain threshold (PPT) testing of the upper and lower extremity before, immediately after and 1 day after treatment. ANCOVAs were used to analyze flexibility data, with the covariate of pre-treatment values. Paired t-tests were used for difference in remote pain sensitivity. RESULTS: Statistically larger improvements in regional flexibility, but not remote flexibility, were observed immediately post-treatment in those who received DN than in those receiving sham DN (p = .0495; adjusted difference 1.2, 95% CI 0.002-2.3). Differences between upper and lower extremity PPT were not significant. CONCLUSION: DN can potentially have immediate changes in regional flexibility, but effects are not sustained at 24-h follow-up. DN may not affect remote flexibility or segmental pain sensitivity.

Normative Parameters of Gastrocnemius Muscle Stiffness and Associations with Patient Characteristics and Function.

BACKGROUND: Quantifying muscle stiffness may aid in the diagnosis and management of individuals with muscle pathology. Therefore, the primary purpose of this study was to establish normative parameters and variance estimates of muscle stiffness in the gastrocnemius muscle in a resting and contracted state. A secondary aim was to identify demographic, anthropometric, medical history factors, and biomechanical factors related to muscle stiffness. METHODS: Stiffness of the gastrocnemius muscle was measured in both a resting and contracted state in 102 asymptomatic individuals in this cross-sectional study. Differences based on muscle state (resting vs contracted) and sex (female vs male) were assessed using a 2 X 2 analysis of variance (ANOVA). Associations between muscle stiffness and sex, age, BMI, race, exercise frequency, exercise duration, force production, and step length were assessed using correlation analysis. RESULTS: Gastrocnemius muscle stiffness significantly increased from a resting to a contracted state [mean difference: 217.5 (95% CI: 191.3, 243.8), p < 0.001]. In addition, muscles stiffness was 35% greater for males than females in a resting state and 76% greater in a contracted state. Greater muscle stiffness in a relaxed and contracted state was associated with larger plantarflexion force production (r = .26, p < 0.01 and r = .23, p < 0.01 respectively). CONCLUSION: Identifying normative parameters and variance estimates of muscle stiffness in asymptomatic individuals may help guide diagnosing and managing individuals with aberrant muscle function. LEVEL OF EVIDENCE: 2b Individual Cohort Study. CLINICAL RELEVANCE: What is known about the subject: Muscle stiffness has been shown to be related to individuals with pathology such as Achilles tendinopathy; however, research is sparse regarding normative values of muscle stiffness. Measuring muscle stiffness may also be a way to potentially predict individuals prone to injury or to monitor the effectiveness of management strategies.What this study adds to existing knowledge: This study establishes defined estimates of muscle stiffness of the gastrocnemius in both a relaxed and contracted state in healthy individuals. Myotonometry measures of muscle stiffness demonstrated an increase in stiffness during contraction that varies by sex. Greater gastrocnemius muscle stiffness was associated with increased plantarflexion force production.

Ultrasound shear wave elastography measurement of the deep posterior cervical muscles: Reliability and ability to differentiate between muscle contraction states.

The deep posterior cervical muscles (DPCM), specifically the semispinalis cervicis and cervical multifidus, are often impaired in patients with neck disorders and have been assessed by several imaging techniques. Prior ultrasound shear wave elastography (SWE) imaging and reliability assessments of the DPCM were performed utilizing similar positioning as assessments for the more superficial cervical extensors. Our objectives were to describe an SWE imaging technique for the DPCM, establish intra-rater reliability of DPCM SWE, and compare DPCM shear modulus during rest and submaximal contraction in both prone and seated positions in individuals without spinal pain. In sixteen participants, the DPCM was located using B-mode ultrasound, then muscle shear modulus was assessed via SWE at both rest and with contraction against a 2-kg resistance applied at the C2 spinous process. Within-day intra-rater reliability was moderate to good (ICC = 0.70-0.88). The DPCM were stiffer during contraction than at rest in the prone position (p = 0.002), and at rest in sitting versus at rest in prone (p = 0.003). Further research is needed to assess DPCM-specific SWE in symptomatic individuals and compare DPCM shear modulus to electromyography across contraction intensities.

Cadaveric and in vivo validation of needle placement in the medial pterygoid muscle.

BACKGROUND: Evidence suggests that medial pterygoid muscle plays an important role in temporomandibular pain. Therapeutic approaches targeting this muscle are needed. OBJECTIVE: To determine if a solid needle accurately penetrates the medial pterygoid muscle during the application of dry needling. DESIGN: A cadaveric and human descriptive study. METHODS: Needling insertion of the medial pterygoid was conducted in 5 fresh cadaver and 5 subjects with temporomandibular pain. Needling insertion was performed using a 40 mm needle inserted at the inferior angle of the mandibular bone. The needle was advanced from an inferior to superior direction into the medial pterygoid to a maximum depth of 30 mm. In cadavers, medial pterygoid placement was assessed by observation after resecting the superficial overlying tissues. In patients, medial pterygoid placement was assessed by self-reported pain referral during insertion. RESULTS: Accurate needle penetration of the medial pterygoid was observed in all fresh cadavers and pain referral was reported by 4/5 patients during needling insertion. CONCLUSION: Results from both cadavers and patients support the assertion that needling of the medial pterygoid can be accurately conducted.

Cost-Effectiveness of Operative Versus Nonoperative Management of Patients With Intra-articular Calcaneal Fractures.

OBJECTIVE: To assess the costs, health gains, and cost-effectiveness of operative versus nonoperative treatment of calcaneal fractures over a 5-year time horizon from both US societal and payer perspectives. METHODS: The societal perspective analysis included both direct medical costs and costs for missed work, whereas the health care payer perspective analysis included only direct medical costs associated with treatment and complications. A decision tree simulation model was developed to estimate the direct medical and indirect costs (2018 US$) and quality-adjusted life-years (QALYs) for treatment of patients sustaining intra-articular calcaneal fractures fixed with an extensile lateral approach. Direct medical costs were obtained from a large US health care system in Utah, Intermountain Healthcare, and indirect costs from the literature. Utility and probability parameters were also derived from the literature. Parameter uncertainty was explored using both one-way and probabilistic sensitivity analysis. RESULTS: From a US societal perspective, operative treatment costs less ($35,110 vs. $39,870) and yielded more QALYs (3.89 vs. 3.51) over 5 years compared with nonoperative treatment. At a willingness-to-pay threshold of $50,000 per QALY, operative fixation had an 89% probability of being cost-effective. From a health care payer perspective, operative management remained cost-effective as the incremental cost-effectiveness ratio is below the willingness-to-pay threshold of $50,000/QALY. CONCLUSION: From both US societal and health care payer perspectives, operative treatment of displaced intra-articular calcaneal fractures utilizing an extensile lateral approach is cost-effective at commonly accepted willingness-to-pay thresholds compared with nonoperative treatment over a 5-year time horizon. Patient variability may impact cost-effectiveness and should be explored in future research. LEVEL OF EVIDENCE: Economic Level III. See Instructions for Authors for a complete description of levels of evidence.