Follistatin Protein Enhances Satellite Cell Counts in Reinnervated Muscle.

Background Muscle recovery following peripheral nerve repair is sup-optimal. Follistatin (FST), a potent muscle stimulant, enhances muscle size and satellite cell counts following reinnervation when administered as recombinant FST DNA via viral vectors. Local administration of recombinant FST protein, if effective, would be more clinically translatable but has yet to be investigated following muscle reinnervation. Objective The aim of this study is to assess the effect of direct delivery of recombinant FST protein on muscle recovery following muscle reinnervation. Materials and Methods In total, 72 Sprague-Dawley rats underwent temporary (3 or 6 months) denervation or sham denervation. After reinnervation, rats received FST protein (isoform FS-288) or sham treatment via a subcutaneous osmotic pump delivery system. Outcome measures included muscle force, muscle histomorphology, and FST protein quantification. Results Follistatin treatment resulted in smaller muscles after 3 months denervation ( p = 0.019) and reduced force after 3 months sham denervation ( p < 0.001). Conversely, after 6 months of denervation, FST treatment trended toward increased force output ( p = 0.066). Follistatin increased satellite cell counts after denervation ( p < 0.001) but reduced satellite cell counts after sham denervation ( p = 0.037). Conclusion Follistatin had mixed effects on muscle weight and force. Direct FST protein delivery enhanced satellite cell counts following reinnervation. The positive effect on the satellite cell population is intriguing and warrants further investigation.

Effects of 4-week impairment-based rehabilitation on jump-landing biomechanics in chronic ankle instability patients.

OBJECTIVE: To determine effects of 4-weeks of impairment-based rehabilitation on lower extremity neuromechanics during jump-landing. DESIGN: Descriptive laboratory study. PARTICIPANTS: Twenty-six CAI subjects (age = 21.4 ± 3.1 sex=(M = 7,F = 19), height = 169.0 ± 8.8 cm, weight = 71.0 ± 13.8 kg) completed 15 jump-landing trials prior to and following 12 supervised rehabilitation sessions. MAIN OUTCOME MEASURES: Frontal and sagittal lower extremity kinematics and kinetics and sEMG amplitudes (anterior tibialis, peroneus brevis, peroneus longus, and medial gastrocnemius). Means and 90% confidence intervals (CIs) were calculated for 100 ms prior to and 200 ms following ground contact. Areas where pre- and post-rehabilitation CIs did not overlap were considered significantly different. Kinematic and kinetic peaks and kinematic excursion were compared with paired t-test (P ≤ 0.05). RESULTS: Following rehabilitation, CAI subjects exhibited less ankle (2.1° (0.8, 3.4), P < 0.01) and hip (2.0° (0.5, 3.7), P = 0.01) frontal plane excursion and lower peak hip abduction (2.5° (0.0, 5.0), P = 0.05). There was less ankle (5.0° (1.7, 8.3), P < 0.01) and knee (3.4° (0.8, 6.0), P = 0.01) sagittal plane excursion following rehabilitation. There was decreased peroneus longus activity from 9 ms to 135 ms post ground contact and decreased peak plantar flexion moment (0.08 N∗m/kg (0.01, 0.13), P = 0.02) following rehabilitation. CONCLUSION: Progressive impairment-based rehabilitation resulted in reductions in kinematic excursion and peroneus longus muscle activity, suggesting a more efficient landing strategy.

Side-to-side supercharging nerve allograft enhances neurotrophic potential.

INTRODUCTION: Critical limitations of processed acellular nerve allograft (PNA) are linked to Schwann cell function. Side-to-side bridge grafting may enhance PNA neurotrophic potential. METHODS: Sprague-Dawley rats underwent tibial nerve transection and immediate repair with 20-mm PNA (n = 33) or isograft (ISO; n = 9) or 40-mm PNA (n = 33) or ISO (n = 9). Processed acellular nerve allograft groups received zero, one, or three side-to-side bridge grafts between the peroneal nerve and graft. Muscle weight, force generation, and nerve histomorphology were tested 20 weeks after repair. Selected animals underwent neuron back labeling with fluorescent dyes. RESULTS: Inner axon diameters, g-ratios, and axon counts were smaller in the distal vs proximal aspect of each graft (P < .05). Schwann cell counts were greater, with a lower proportion of senescent cells for groups with bridges (P < .05). Retrograde labeling demonstrated that 6.6% to 17.7% of reinnervating neurons were from the peroneal pool. DISCUSSION: Bridge grafting positively influenced muscle recovery and Schwann cell counts and senescence after long PNA nerve reconstruction.

Viral vector delivery of follistatin enhances recovery of reinnervated muscle.

INTRODUCTION: Poor recovery following nerve repair is due to progressive temporal loss of muscle function. Follistatin (FS), a glycoprotein with anabolic properties, may enhance muscle recovery following reinnervation. METHODS: Seventy-two male Sprague-Dawley rats underwent temporary (3 or 6 month) denervation or sham denervation. After reinnervation, rats were administered adeno-associated viral vectors expressing FS deoxyribonucleic acid (isoform FS-317) injected into the target muscle or sham treatment. Final assessment included muscle function testing, muscle histomorphology, nerve histomorphology, and FS protein quantification. RESULTS: FS improved muscle mass and type IIB muscle fiber size, and increased G-ratios and mean axon diameter in the 6-month temporary denervation group (P < .05). Elevated FS protein levels were detected in treated muscle (P < .05). FS increased satellite cell counts following temporary denervation and repair (P < .05). DISCUSSION: FS treatment had anabolic, neurotrophic, and satellite cell stimulatory effects when administered following prolonged (6-month) temporary denervation and repair.

Effect of Impairment-Based Rehabilitation on Lower Leg Muscle Volumes and Strength in Patients With Chronic Ankle Instability: A Preliminary Study.

Context: Patients with chronic ankle instability (CAI) have demonstrated atrophy of foot and ankle musculature and deficits in ankle strength. The effect of rehabilitation on muscle morphology and ankle strength has not previously been investigated in patients with CAI. Objective: Our objective was to analyze the effect of impairment-based rehabilitation on intrinsic and extrinsic foot and ankle muscle volumes and strength in patients with CAI. Design: Controlled laboratory study. Setting: Laboratory. Patients: Five young adults with CAI. Intervention: Twelve sessions of supervised impairment-based rehabilitation that included range of motion, strength, balance, and functional exercises. Main Outcome Measures: Measures of extrinsic and intrinsic foot muscle volume and ankle strength measured before and after 4 weeks of supervised rehabilitation. Novel fast-acquisition magnetic resonance imaging was used to scan from above the femoral condyles through the entire foot. The perimeter of each muscle was outlined on each axial slice and then the 2-dimensional area was multiplied by the slice thickness (5 mm) to calculate muscle volume. Plantar flexion, dorsiflexion, inversion, and eversion isometric strength were measured using a hand-held dynamometer. Results: Rehabilitation resulted in hypertrophy of all extrinsic foot muscles except for the flexor hallucis longus and peroneals. Large improvements were seen in inversion, eversion, and plantar flexion strength following rehabilitation. Effect sizes for significant differences following rehabilitation were all large and ranged from 1.54 to 3.35. No significant differences were identified for intrinsic foot muscle volumes. Conclusion: Preliminary results suggest that impairment-based rehabilitation for CAI can induce hypertrophy of extrinsic foot and ankle musculature with corresponding increases in ankle strength.

Step-Down Task Identifies Differences in Ankle Biomechanics Across Functional Activities.

Currently, there is no clinical exam to evaluate ankle frontal plane kinematics. The purpose of this study was to determine whether individuals identified as "lateral" landing during a video-recorded step-down task have differences in ankle inversion as measured with 3-dimensional motion capture during walking, step-down, and jump-landing tasks compared to individuals identified as "non-lateral". Fifty-seven recreationally active adults completed the descriptive laboratory study. During walking, step-down, and jump-landing tasks, participants had their ankle frontal plane kinematics measured using a 3-dimensional motion capture system. In addition, during the step-down task, participants had a posterior view video of their foot recorded using a commercial camera. Following testing, a blinded-investigator scored the step-down video of all participants by classifying them as "lateral" landing or "non-lateral" landing. Ankle frontal plane kinematics during the walking, step-down, and jump-landing tasks were compared between the two groups (lateral (N=24) and non-lateral (N=33) using a binary logistic regression and time-series confidence interval analysis. During walking, stepping-down, and jump-landing, the lateral group had significantly more inversion at initial contact and during various other phases specific to each task. This study found that a clinical screening tool could identify individuals who have significantly more inversion during three tasks.

Lower Extremity Biomechanics During a Drop-Vertical Jump in Participants With or Without Chronic Ankle Instability.

CONTEXT: Chronic ankle instability (CAI) is a condition characterized by range-of-motion, neuromuscular, and postural-control deficits and subjective disability, reinjury, and posttraumatic osteoarthritis. Differences have been reported in kinematics, kinetics, surface electromyography (EMG), and ground reaction forces during functional tasks performed by those with CAI. These measures are often collected independently, and the research on collecting measures simultaneously during a movement task is limited. OBJECTIVE: To assess the kinematics and kinetics of the lower extremity, vertical ground reaction force (vGRF), and EMG of 4 shank muscles during a drop-vertical-jump (DVJ) task. DESIGN: Controlled laboratory study. SETTING: Motion-capture laboratory. PATIENTS OR OTHER PARTICIPANTS: Forty-seven young, active adults in either the CAI (n = 24) or control (n = 23) group. INTERVENTION(S): Three-dimensional motion capture was performed using an electromagnetic motion-capture system. Lower extremity kinematics, frontal- and sagittal-plane kinetics, vGRF, and EMG of the shank musculature were collected while participants performed 10 DVJs. MAIN OUTCOME MEASURE(S): Means and 90% confidence intervals were calculated for all measures from 100 milliseconds before to 200 milliseconds after force-plate contact. RESULTS: Patients with CAI had greater inversion from 107 to 200 milliseconds postcontact (difference = 4.01° ± 2.55°), smaller plantar-flexion kinematics from 11 to 71 milliseconds postcontact (difference = 5.33° ± 2.02°), greater ankle sagittal-plane kinetics from 11 to 77 milliseconds postcontact (difference = 0.17 ± 0.09 Nm/kg) and from 107 to 200 milliseconds postcontact (difference = 0.23 ± 0.03 Nm/kg), and smaller knee sagittal-plane kinematics from 95 to 200 milliseconds postcontact (difference = 8.23° ± 0.97°) than control participants after landing. The patients with CAI had greater vGRF from 94 to 98 milliseconds postcontact (difference = 0.83 ± 0.03 N/kg) and peroneal activity from 17 to 128 milliseconds postcontact (difference = 10.56 ± 4.52 N/kg) than the control participants. CONCLUSIONS: Patients with CAI presented with differences in their landing strategies that may be related to continued instability. Kinematic and kinetic changes after ground contact and greater vGRF may be related to a faulty landing strategy. The DVJ task should be considered for rehabilitation protocols in these individuals.

Variability in center of pressure position and muscle activation during walking with chronic ankle instability.

Chronic ankle instability (CAI) patients exhibit altered gait mechanics. The objective was to identify differences in stride-to-stride variability in the position of the center of pressure (COP) and muscle activity during walking between individuals with and without CAI. Participants (17 CAI;17 Healthy) walked on a treadmill at 1.3 m/s while surface electromyography (sEMG) of the fibularis longus (FL) and plantar pressure were recorded. The medial-lateral COP position was averaged for each 10% interval of stance and group standard deviations (SD), coefficient of variation (COV), and range for the COP position were compared between groups via independent t-tests. Ensemble curves for sEMG amplitude SD were graphed for the entire stride cycle to determine significant differences. The CAI group had increased COP position variability (SD (CAI = 0.79 ±â€¯0.47 mm, Control = 0.48 ±â€¯0.17 mm), COV (CAI = 1.47 ±â€¯0.87 mm, Control = 0.93 ±â€¯0.33 mm), range (CAI = 2.97 ±â€¯2.07 mm, Control = 1.72 ±â€¯0.33 mm, P < .05 for all analyses)) during the first 10% of stance. The CAI group had lower FL sEMG amplitude variability from 1 to 10% (mean difference = 0.014 ±â€¯0.006), 32-38% (mean difference = 0.013 ±â€¯0.004) and 56-100% (mean difference = 0.026 ±â€¯0.01) of the gait cycle. Increased COP variability at initial contact may increase risk of lateral ankle sprains in CAI patients. Decreased sEMG amplitude variability may indicate a constrained sensorimotor system contributing to an inability to adapt to changing environmental demands.

Acute lateral ankle sprain to chronic ankle instability: a pathway of dysfunction.

Lateral ankle sprains (LAS) have been reported as one of the most common musculoskeletal injuries observed in sports and in individuals who are recreationally active. Approximately 40% of individuals who sustain a LAS develop a condition known as chronic ankle instability (CAI). Years of research has identified numerous impairments associated with CAI such as decreases in range of motion (ROM), strength, postural control, and altered movement patterns during functional activities when compared to individuals with no LAS history. As a result, an impairment-based rehabilitation model was developed to treat the common impairments associated with CAI. The impairment-based rehabilitation model has been shown to be an effective rehabilitation strategy at improving both clinical and patient-oriented outcomes in patients with CAI. To date, the efficacy of an impairment-based rehabilitation model has not been evaluated in patients with an acute LAS. Prior to implementing an impairment-based model for the treatment of an acute LAS, similarities between impairments associated with acute LAS and CAI across the spectrum of the healing process is warranted. Therefore, the purpose of this review paper is to compare and contrast impairments and treatment techniques in individuals with an acute LAS, sub-acute LAS, and CAI. A secondary purpose of this review is to provide clinical commentary on the management of acute LAS and speculate how the implementation of an impairment-based rehabilitation strategy for the treatment of acute LAS could minimize the development of CAI. The main findings of this review were that similar impairments (decreased ROM, strength, postural control, and functional activities) are observed in patients with acute LAS, sub-acute LAS, and CAI, suggesting that the impairments associated with CAI are a continuation from the original impairments developed during the initial LAS. Therefore, the use of an impairment-based model may be advantageous when treating patients with an acute LAS.

Gait training for chronic ankle instability improves neuromechanics during walking.

A novel gait-training device has been shown to improve gait patterns while patients with chronic ankle instability (CAI) are using the device and our current objective was to analyze the effect of structured gait training with the device on plantar pressure and surface electromyography (sEMG) following repeated gait training sessions. Sixteen CAI patients participated. Plantar pressure and sEMG were collected simultaneously during walking pre- and post-gait training. Plantar pressure (pressure time integral, peak pressure, time to peak pressure, contact area, contact time, and center of pressure trajectory) of the entire foot and nine specific regions of the foot were recorded concurrently with sEMG root mean square amplitudes from the anterior tibialis, peroneus longus, medial gastrocnemius, and gluteus medius. Five gait training sessions were performed with each session lasting approximately 15 min. Pre- and post-gait training self-reported function, plantar pressure, and sEMG were compared using paired t-tests with a priori level of significance of p ≤ 0.05. Gait training improved self-reported function (FAAM-Sport scale: Pre = 75.1 ± 7.1%, Post = 85.7 ± 12.2%, p < 0.001) and caused a medial shift in the COP from 10% of stance through toe-off (p < 0.05 for all analyses). The medial shift in COP was driven by concurrent increases in peroneus longus muscle activity from 21% to 60% and 81% to 90% of stance (p < 0.05 for all analyses). There was a corresponding reduction in gluteus medius muscle activity during 71-100% of stance (p < 0.05 for all analyses). Overall, gait training with a device that targets the peroneus longus and gluteus medius throughout the gait cycle improved gait patterns in CAI patients. © 2017 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 36:515-524, 2018.

Validating Center-of-Pressure Balance Measurements Using the MatScan® Pressure Mat.

CONTEXT: Measurements of center-of-pressure (COP) excursions during balance are common practice in clinical and research settings to evaluate adaptations in postural control due to pathological or environmental conditions. Traditionally measured using laboratory force plates, pressure-mat devices may be a suitable option for clinicians and scientist to measure COP excursions. OBJECTIVE: Compare COP measures and changes during balance between MatScan® pressure mat and force plate. DESIGN: Validation study. SETTING: Laboratory. PARTICIPANTS: 30 healthy, young adults (19 female, 11 male, 22.7 ± 3.4 y, 70.3 ± SD kg, 1.71 ± 0.09 m). MAIN OUTCOMES: COP excursions were simultaneously measured using pressure-mat and force-plate devices. Participants completed 3 eyes-open and 3 eyes-closed single-leg balance trials (10 s). Mean of the 3 trials was used to calculate 4 COP variables: medial-lateral and anterior-posterior excursion, total distance, and area with eyes open and eyes closed. Percent change and effect sizes were calculated between eyes-open to eyes-closed conditions for each variable and for both devices. RESULTS: All COP variables were highly correlated between devices for eyes-open and eyes-closed conditions (all r > .92, P < .001). Bland-Altman plots suggest the pressure-mat COP measurements were smaller than those of the force-plate, and the differences between devices appeared to increase as the measurement magnitude increased. Percent change in COP variables was highly correlated between devices (r > .85, P < .001). Cohen d effect sizes between eyes-open and eyes-closed were all large (d > 2.25) and similar in magnitude between devices. CONCLUSION: COP measures were correlated between devices, but values tended to be smaller using the pressure mat. The pressure mat and force plate detected comparable magnitude changes in COP measurements between eyes-open and eyes-closed. Pressure mats may provide a viable option for detecting large magnitude changes in postural control during short-duration testing.

Relationship between ankle frontal plane kinematics during different functional tasks.

Increased inversion following lateral ankle sprain and in patients with chronic ankle instability (CAI) is thought to contribute to recurrent injury and feelings of instability, however, there are no biomechanic assessment tools readily available to evaluate for excessive inversion prior to or following lateral ankle sprains. Before establishing a clinically useful biomechanic assessment tool, it is important to understand whether there is a relationship in the extent of ankle frontal plane motion across various tasks to help determine if one task or a combination of tasks would be most appropriate when evaluating patients. The purpose of this preliminary study was to analyze the relationship between ankle frontal plane kinematics during walking, step-down, and jump-landing tasks. Fifty-six recreationally active adults (gender=M:26;F:30, age=21.2±3.2, height=171.3±8.0cm, mass=75.6±15.4) volunteered. Main outcome measures were ankle frontal plane motion at initial contact and peak inversion during aerial phases across 3 tasks (walking, step-down, and jump-landing). Relationships between ankle frontal plane kinematics were analyzed by Pearson product-moment correlation coefficient (r). There were strong correlations in peak inversion during the aerial phase between the step-down and walking (r=0.68; p<0.001) and step-down and jump-landing (r=0.75; p<0.001) and at initial contact between step-down and walking (r=0.73; p<0.001) and step-down and jump-landing (r=0.72; p<0.001). Moderate correlations were identified during aerial (r=0.32; p=0.015) and at initial contact (r=0.46; p<0.001) between walking and jump-landing. The strong relationship between the amount of inversion exhibited across various tasks suggest that a single evaluation test may be sufficient in the identification of abnormal ankle biomechanics.

Does partial muscle reinnervation preserve future re-innervation potential?

INTRODUCTION: Late revision nerve surgery for incomplete motor recovery due to partial reinnervation would improve muscle function if all muscle fibers were protected from developing denervation atrophy. METHODS: Sixty immature Sprague-Dawley rats underwent the following tibial nerve manipulations (n = 15/group): group A, partial denervation (two thirds of nerve resected and the remaining one third crushed), revision repair at 8 months; group B, partial denervation; group C, complete denervation, immediate reconstruction; group D, complete denervation, reconstruction at 8 months; and group E, control. Final testing at 11 months included muscle force, weight, and histology. RESULTS: Muscle weight was significantly (P < 0.05) different among all groups (highest to lowest: E > B > C > A > D), and force was significantly lower in groups A and D compared with E. Muscle fiber cross-sectional area was statistically smaller in group A than in groups B, C, or E. DISCUSSION: Partial reinnervation still allowed substantial muscle recovery, but it did not preserve the non-innervated muscle fibers. Muscle Nerve 56: 1143-1148, 2017.

Current Trends in the Management of Lateral Ankle Sprain in the United States.

OBJECTIVE: To characterize trends in the acute management (within 30 days) after lateral ankle sprain (LAS) in the United States. DESIGN: Descriptive epidemiology study. PATIENTS: Of note, 825 718 ankle sprain patients were identified; 96.2% were patients with LAS. Seven percent had an associated fracture and were excluded from the remaining analysis. SETTING: Primary and tertiary care settings. INTERVENTIONS: We queried a database of national health insurance records for 2007 to 2011 by ICD-9 codes for patients with LAS while excluding medial and syndesmotic sprains and any LAS with an associated foot or ankle fracture. MAIN OUTCOME MEASURES: The percentage of patients to receive specific diagnostic imaging, orthopedic devices, or physical therapy treatments within 30 days of the LAS diagnosis and the associated costs. RESULTS: Over two-thirds of patients with LAS without an associated fracture received radiographs, 9% received an ankle brace, 8.1% received a walking boot, 6.5% were splinted, and 4.8% were prescribed crutches. Only 6.8% received physical therapy within 30 days of their LAS diagnosis, 94.1% of which performed therapeutic exercise, 52.3% received manual therapy, and 50.2% received modalities. The annual cost associated with physician visits, diagnostic imaging, orthopedic devices, and physical therapy was 152 million USD, 81.5% was from physician evaluations, 7.9% from physical therapy, 7.2% from diagnostic imaging, and 3.4% from orthopedic devices. CONCLUSIONS: Most patients with LAS do not receive supervised rehabilitation. The small proportion of patients with LAS to receive physical therapy get rehabilitation prescribed in accordance with clinical practice guidelines. The majority (>80%) of the LAS financial burden is associated with physician evaluations.

CLINICAL COMMENTARY ON MIDFOOT AND FOREFOOT INVOLVEMENT IN LATERAL ANKLE SPRAINS AND CHRONIC ANKLE INSTABILITY. PART 2: CLINICAL CONSIDERATIONS.

Lateral ankle sprains (LAS) and chronic ankle instability (CAI) are common musculoskeletal injuries that are a result of inversion injury during sport. The midfoot and forefoot is frequently injured during a LAS, is often overlooked during clinical examination, and maybe contributory to the development of CAI. The purpose of part two of this clinical commentary and current concept review is to increase clinician's awareness of the contribution of midfoot and forefoot impairment to functional limitation and disability of individuals who experience LAS and CAI and to facilitate future research in this area. The importance of multisegmented foot and ankle assessment from a clinical and research perspective is stressed. Select physical assessment and manual therapeutic techniques are presented to assist the clinician in examination and treatment of the ankle-foot complex in patients with LAS and CAI.

MIDFOOT AND FOREFOOT INVOLVEMENT IN LATERAL ANKLE SPRAINS AND CHRONIC ANKLE INSTABILITY. PART 1: ANATOMY AND BIOMECHANICS.

The modern human foot is the culmination of more than five million years of evolution. The ankle-foot complex absorbs forces during loading, accommodates uneven surfaces, and acts as a lever for efficient propulsion. The ankle-foot complex has six independent functional segments that should be understood for proper assessment and treatment of foot and ankle injuries: the shank, rearfoot, midfoot, lateral forefoot, and the medial forefoot. The compliance of the individual segments of the foot is dependent on velocity, task, and active and passive coupling mechanisms within each of the foot segments. It is also important to understand the passive, active, and neural subsystems that are functionally intertwined to provide structure and control to the multisegmented foot. The purpose of the first part of this clinical commentary and current concepts review was to examine foot and ankle anatomy, detail the roles of the intrinsic and extrinsic foot and ankle musculature from a multisegmented foot perspective, and discuss the biomechanics of the ankle-foot complex during function. The interplay of segmental joint mobility, afferent and efferent sensorimotor function, and movement and stabilization provided by the extrinsic and intrinsic musculature is required to coordinate and execute the complex kinematic movements in the ankle-foot complex during propulsion. LEVEL OF EVIDENCE: 5.

Intrinsic Foot Muscle Activation During Specific Exercises: A T2 Time Magnetic Resonance Imaging Study.

CONTEXT: The intrinsic foot muscles maintain the medial longitudinal arch and aid in force distribution and postural control during gait. Impaired intrinsic foot-muscle function has been linked to various foot conditions. Several rehabilitative exercises have been proposed to improve it; however, literature that identifies which individual muscles are activated during specific intrinsic foot-muscle exercises is lacking. OBJECTIVE: To describe changes in activation of the intrinsic plantar foot muscles after 4 exercises as measured with T2 magnetic resonance imaging (MRI). DESIGN: Descriptive laboratory study. SETTING: Research laboratory. PATIENTS OR OTHER PARTICIPANTS: Eight healthy National Collegiate Athletic Association Division I collegiate cross-country and track athletes (5 men and 3 women: age = 20 ± 0.93 years, height = 180.98 ± 10.84 cm, mass = 70.91 ± 7.82 kg). INTERVENTION(S): Participants underwent T2 MRI before and after each exercise. They completed 1 set of 40 repetitions of each exercise (short-foot exercise, toes spread out, first-toe extension, second- to fifth-toes extension). MAIN OUTCOME MEASURE(S): Percentage increases in muscle activation of the abductor hallucis, flexor digitorum brevis, abductor digiti minimi, quadratus plantae, flexor digiti minimi, adductor hallucis oblique, flexor hallucis brevis, and interossei and lumbricals (analyzed together) after each exercise were assessed using T2 MRI. RESULTS: All muscles showed increased activation after all exercises. The mean percentage increase in activation ranged from 16.7% to 34.9% for the short-foot exercise, 17.3% to 35.2% for toes spread out, 13.1% to 18.1% for first-toe extension, and 8.9% to 22.5% for second- to fifth-toes extension. All increases in activation had associated 95% confidence intervals that did not cross zero. CONCLUSIONS: Each of the 4 exercises was associated with increased activation in all of the plantar intrinsic foot muscles evaluated. These results may have clinical implications for the prescription of specific exercises to target individual intrinsic foot muscles.

Surgical treatment of Lenke 5 adolescent idiopathic scoliosis: Comparison of anterior vs posterior approach.

AIM: To compare the posterior vs anterior approaches for fusion of Lenke 5 adolescent idiopathic scoliosis curves, matched for curve magnitude and for the distal level of fixation (dLOF) standardized to the third lumbar vertebrae (L3). METHODS: A prospectively collected multicenter database was used for this retrospective comparative study. Our dependent variables included sagittal and coronal radiographic measurements, number of fused vertebrae, estimated blood loss, length of hospitalization and SRS total and individual domain scores at the two-year follow-up. Subject demographics were similar for all group comparisons. Independent t-test was used to compare groups for all analyses at P < 0.01. RESULTS: For all matched cases of Lenke 5 curves, a selective approach was used only 50% of the time in cases undergoing a posterior fusion. When comparing a posterior selective approach to an anterior selective approach, surgeons utilizing a posterior approach fused significantly more levels than surgeons using an anterior approach with no other significant differences in radiographic or SRS outcomes (Ant = 4.8 ± 1.0 levels vs post = 6.1 ± 1.0 levels, P < 0.0001). When the dLOF was standardized to L3, the anterior approached provided significantly greater lumbar Cobb percent correction than the posterior approach (Ant = 69.1% ± 12.6% vs post = 54.6% ± 16.4%, P = 0.004), with no other significant radiographic or SRS score differences between approaches. CONCLUSION: Surgeons treating Lenke 5c curves with a posterior instrumentation and fusion vs an anterior approach include more motion segments, even with a selective fusion. When controlled for the distal level of fixation, the anterior approach provides greater correction of the thoracolumbar curve.

Diminished Foot and Ankle Muscle Volumes in Young Adults With Chronic Ankle Instability.

BACKGROUND: Patients with chronic ankle instability (CAI) have demonstrated altered neuromuscular function and decreased muscle strength when compared with healthy counterparts without a history of ankle sprain. Up to this point, muscle volumes have not been analyzed in patients with CAI to determine whether deficits in muscle size are present following recurrent sprain. PURPOSE: To analyze intrinsic and extrinsic foot and ankle muscle volumes and 4-way ankle strength in young adults with and without CAI. STUDY DESIGN: Cross-sectional study; Level of evidence, 3. METHODS: Five patients with CAI (mean age, 23.0 ± 4 years; 1 male, 4 females) and 5 healthy controls (mean age, 23.8 ± 4.5 years; 1 male, 4 females) volunteered for this study. Novel fast-acquisition magnetic resonance imaging (MRI) was used to scan from above the femoral condyles through the foot and ankle. The perimeter of each muscle was outlined on each axial slice and then the 2-dimensional area was multiplied by the slice thickness (5 mm) to calculate the muscle volume. Plantar flexion, dorsiflexion, inversion, and eversion isometric strength were measured using a handheld dynamometer. Patients with CAI were compared with healthy controls on all measures of muscle volume and strength. Extrinsic muscle volumes of patients with CAI were also compared with a normative database of healthy controls (n = 24) by calculating z scores for each muscle individually for each CAI subject. RESULTS: The CAI group had smaller total shank, superficial posterior compartment, soleus, adductor hallucis obliqus, and flexor hallucis brevis muscle volumes compared with healthy controls as indicated by group means and associated 90% CIs that did not overlap. Cohen d effect sizes for the significant group differences were all large and ranged from 1.46 to 3.52, with 90% CIs that did not cross zero. The CAI group had lower eversion, dorsiflexion, and 4-way composite ankle strength, all with group means and associated 90% CIs that did not overlap. No other significant differences were identified. CONCLUSION: Patients with CAI demonstrate atrophy of intrinsic and extrinsic foot and ankle musculature accompanied by lower ankle strength. CLINICAL RELEVANCE: Clinicians should be aware of the muscle atrophy and strength deficits when prescribing rehabilitation for patients with lateral ankle sprain or CAI.

Effects of ankle destabilization devices and rehabilitation on gait biomechanics in chronic ankle instability patients: A randomized controlled trial.

UNLABELLED: Patients with chronic ankle instability (CAI) have altered gait patterns, which are characterized by increased inversion positioning during gait. Ankle destabilization devices increase peroneus longus muscle activation during gait, which may increase eversion. OBJECTIVE: To determine whether incorporating destabilization devices into a 4-week impairment-based rehabilitation program has beneficial effects on gait biomechanics and surface electromyography (sEMG) compared to impairment-based rehabilitation without destabilization devices in CAI patients. DESIGN: Randomized controlled trial. SETTING: Laboratory. PARTICIPANTS: Twenty-six CAI patients. OUTCOME MEASURES: Patients completed baseline gait trials and were randomized into no device or device groups. Groups completed 4-weeks of rehabilitation with or without devices, and then completed post-intervention gait trials. Lower extremity sagittal and frontal plane kinematics and kinetics and sEMG activity were measured. RESULTS: The device group increased dorsiflexion during mid-late stance and had lower normalized sEMG amplitude for the peroneus longus during early stance and mid-swing after rehabilitation. The no device group had less peroneus brevis sEMG activity during early stance after rehabilitation. CONCLUSION: Incorporating destabilization devices in a 4-week rehabilitation program was an effective method of improving dorsiflexion during the stance phase of gait. However, impairment-based rehabilitation, regardless of instability tool, was not effective at improving frontal plane motion.