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Objectives: To evaluate the safety and acceptability of a novel 8-week intervention integrating exercise, exposure therapy, cognitive restructuring, and a home safety evaluation, conducted by a physical therapist, in reducing fear of falling and activity avoidance. To collect preliminary evidence of efficacy.Design: Randomized pilot study comparing the intervention to time- and attention-equivalent fall prevention education.Setting: Participants' homes.Participants: 42 older adults with disproportionate fear of falling (high fear, low to moderate objective fall risk).Measurements: Falls Efficacy Scale-International, modified Activity Card Sort, satisfaction, falls.Results: Relative to education, the intervention reduced fear of falling (d = 1.23) and activity avoidance (d = 1.02) at 8 weeks, but effects eroded over a 6-month follow-up period. The intervention did not increase falls, and participants rated the exercise, exposure therapy, and non-specific elements as most helpful.Conclusions: An integration of exercise and exposure therapy may help older adults with disproportionate fear of falling, but modifications to the intervention or its duration may be needed to maintain participants' gains. [ABSTRACT FROM AUTHOR]

* BACKGROUND: The relationship between lumbar spine posture and muscle structure is not well understood. * OBJECTIVES: To investigate the predictive capacity of muscle structure on lumbar spine posture in active-duty Marines. * METHODS: Forty-three Marines were scanned in this cross-sectional study, using an upright magnetic resonance imaging scanner while standing without load and standing, sitting, and prone on elbows with body armor. Cobb, horizontal, and sacral angles were measured. Marines were then scanned while unloaded in supine using a supine magnetic resonance imaging scanner. The imaging protocol consisted of T2 intervertebral disc mapping; high-resolution, anatomical, fat-water separation, and diffusion tensor imaging to quantify disc hydration and muscle volume, fat fraction, and restricted diffusion profiles in the lumbar muscles. A stepwise multiple linear regression model was used to identify physiological measures predictive of lumbar spine posture. * RESULTS: The multiple regression model demonstrated that fractional anisotropy of the erector spinae was a significant predictor of lumbar posture for 7 of 18 dependent variables measured, and explained 20% to 35% of the variance in each model. Decreased fractional anisotropy of the erector spinae predicted decreased lordosis, lumbosacral extension, and anterior pelvic tilt. * CONCLUSION: Fractional anisotropy is inversely related with muscle fiber size, which is associated with the isometric force-generating capacity of a muscle fiber. This suggests that stronger erector spinae muscles predict decreased lordosis, lumbosacral extension, and anterior pelvic tilt in a highly trained population. [ABSTRACT FROM AUTHOR]

Rotator cuff (RC) disease is an extremely common condition associated with shoulder pain, reduced functional capacities, and impaired quality of life. It primarily involves alterations in tendon health and mechanical properties that can ultimately lead to tendon failure. RC tendon tears induce progressive muscle changes that have a negative impact on surgical reparability of the RC tendons and clinical outcomes. At the same time, a significant base of clinical data suggests a relatively weak relationship between RC integrity and clinical presentation, emphasizing the multifactorial aspects of RC disease. This review aims to summarize the potential contribution of peripheral, spinal, and supraspinal neural factors that may (1) exacerbate structural and functional muscle changes induced by tendon tear, (2) compromise the reversal of these changes during surgery and rehabilitation, (3) contribute to pain generation and persistence of pain, (4) impair shoulder function through reduced proprioception, kinematics, and muscle recruitment, and (5) help explain interindividual differences and response to treatment. Given the current clinical and scientific interest in peripheral nerve injury in the context of RC disease and surgery, we carefully reviewed this body of literature with a particular emphasis on suprascapular neuropathy that has generated a large number of studies in the past decade. Within this process, we highlight the gaps in current knowledge and suggest research avenues for scientists and clinicians. [ABSTRACT FROM AUTHOR]

Background Understanding rotator cuff muscle function during disease development and after repair is necessary for preventing degeneration and improving postsurgical outcomes, respectively. The rat is a commonly used rotator cuff animal model; however, unlike humans, rats continue to grow throughout their lifespan, so age-related changes in muscle structure may complicate an understanding of muscle adaptations to injury. Methods Infraspinatus and supraspinatus muscle mass, fiber length, pennation angle, sarcomere length, and physiological cross-sectional area (PCSA) were measured in Sprague-Dawley rats (n = 30) with a body mass ranging from 51 to 814 g (approximately 3 weeks to approximately 18 months). Results Both the supraspinatus and infraspinatus showed a striking conservation of sarcomere length throughout growth. There was linear growth in muscle mass and PCSA, nonlinear growth in muscle length and fiber bundle length, and a linear relationship between humeral head diameter and fiber bundle length, suggesting that muscle fiber length (serial sarcomere number) adjusted according to skeletal dimensions. These muscle growth trajectories allowed sarcomere length to remain nearly constant. Discussion During the typical rat rotator cuff experimental period (animal mass, 400-600 g), muscle mass will increase by 30%, fiber length will increase by 7%, and PCSA will increase by 27%, but sarcomere lengths are nearly constant. Therefore, these normal growth-induced changes in architecture must be considered when muscle atrophy or fiber shortening is measured after rotator cuff tears in this model. [ABSTRACT FROM AUTHOR]

Abstract: The purpose of this study was to evaluate patient perception of orthopedic surgeon reimbursement for total hip (THA) and knee (TKA) arthroplasty. A total of 1120 consecutive patients were asked what they believed a surgeon should be paid for performing THA and TKA. Patients were then asked to estimate what Medicare actually reimbursed for each of these procedures. On average, patients thought that surgeons should receive $14 358 for THA and $13 332 for TKA. Patients estimated actual Medicare reimbursement to be $8212 for THA and $7196 for TKA. Most of the patients stated that Medicare reimbursement was “much lower” than what it should be. Many patients commented that given this discrepancy, surgeons may drop Medicare, which may decrease access to quality hip and knee arthroplasties. [Copyright &y& Elsevier]

The article discusses a study which measured the architectural properties of rat supraspinatus muscle following complete detachment of its distal tendon. Study authors released supraspinatus muscles from the left humerus of 29 Sprague-Dawley rats. They then measured the muscle mass, pennation angle, fiber bundle length and sarcomere length of the muscles. They concluded that the release of supraspinatus muscle resulted to radial and longitudinal muscle atrophy.

Purpose: Tendon transfer is often used to restore key pinch after cervical spinal cord injury. Current postoperative recommendations include elbow immobilization in a flexed position to protect the brachioradialis–flexor pollicis longus (BR-FPL) repair. The purpose of this study was to measure the BR-FPL tendon tension across a range of wrist and elbow joint angles to determine whether joint motion could cause repair rupture. Methods: We performed BR-to-FPL tendon transfers on fresh-frozen cadaveric arms (n = 8) and instrumented the BR-FPL tendon with a buckle transducer. Arms were ranged at 4 wrist angles from 45° of flexion to 45° of extension and 8 elbow angles from 90° of flexion to full extension, measuring tension across the BR-FPL repair at each angle. Subsequently, the BR-FPL tendon constructs were removed and elongated to failure. Results: Over a wide wrist and elbow range of motion, BR-FPL tendon tension was under 20 N. Two-way analysis of variance with repeated measures revealed a significant effect of wrist joint angle (p<.001) and elbow joint angle (p<.001) with significant interaction between elbow and joint angles (p<.001). Because the failure load of the repair site was 203 ± 19 N, over 10 times the loads that would be expected to occur at the repair site, our results demonstrate that the repair has a safety factor of at least 10. Conclusions: Our tendon force measurements support the assertion that the elbow joint need not be immobilized when the BR is used as a donor muscle in tendon transfer to the FPL. This is based on the fact that maximum passive tendon tension was only about 20 N in our cadaveric model and the failure strength of this specific repair was over 200 N. We suggest that it is possible to consider performing multiple tendon transfers in a single stage, avoiding immobilization, which may adversely affect functional recovery. These results must be qualified by the fact that issues unique to living tissues such as postoperative edema and tendon gliding cannot be accounted for by this cadaveric model. [Copyright &y& Elsevier]

Purpose: The side-to-side (SS) tendon suture technique was designed to function as a repair that permits immediate postoperative activation and mobilization of a transferred muscle. This study was designed to test the strength and stiffness of the SS technique against a variation of the Pulvertaft (PT) repair technique. Methods: Flexor digitorum superficialis (FDS) and flexor digitorum profundus (FDP) tendons were harvested from 4 fresh cadavers and used as a model system. Seven SS and 6 PT repairs were performed, using the FDS as the donor and the FDP as the recipient tendon. For SS repairs, the FDS was woven through one incision in the FDP and was joined with 4 cross-stitch running sutures down both sides and one double-loop suture at each tendon free end. For PT repairs, the FDS was woven through 3 incisions in the FDP and joined with a double-loop suture at both ends of the overlap and 4 evenly spaced mattress sutures between the ends. Tendon repairs were placed in a tensile testing machine, preconditioned, and tested to failure. Results: There were no statistically significant differences in cross-sectional area (p = .99) or initial length (p = .93) between SS and PT repairs. Therefore, all comparisons between methods were made using measures of loads and deformations, rather than stresses and strains. All failures occurred in the repair region, rather than at the clamps. However, failure mechanisms were different between the 2 techniques—PT repairs failed by the suture knots either slipping or pulling through the tendon material, followed by the FDS tendon pulling through the FDP tendon; SS repairs failed by shearing of fibers within the FDS. Load at first failure, ultimate load, and repair stiffness were all significantly different between SS and PT techniques; in all cases, the mean value for SS was higher than for PT. Conclusions: The SS repair using a cross-stitch suture technique was significantly stronger and stiffer than the PT repair using a mattress suture technique. This suggests that using SS repairs could enable patients to load the repair soon after surgery. Ultimately, this should reduce the risk of developing adhesions and result in improved functional outcome and fewer complications in the acute postoperative period. Future work will address the specific mechanisms (eg, suture-throw technique and tendon-weave technique) that underlie the improved strength and stiffness of the SS repair. [Copyright &y& Elsevier]

The authors examine the fundamental organization and physiology of the muscles controlling hip movement. Muscle architecture, the organization of fibers within the muscle, is responsible for defining the performance capacity of the muscle. Illustrative examples relevant to lower extremity rehabilitation are presented. Data showed the importance of muscle physiology and joint mechanics in the evaluation and treatment of musculoskeletal disorders.

The article discusses the structure-function relationships of skeletal muscle in the context of a comprehensive data set of hip muscle architecture. The performance of a muscle is based on the network of fibers found within. The data presented show the structural and functional specialization of the muscles in the hip and stress on the importance of muscle physiology and joint mechanics for diagnosis and treatment of patients with musculoskeletal disorders.

Purpose: To compare single-site intraoperative sarcomere length values with sarcomere lengths measured from systematic sampling of the entire transferred muscle. Methods: The tendon of the rabbit second toe extensor muscle was transposed to the ankle extensor retinaculum under levels of stretch over the sarcomere length range of about 2.5 μm to about 4.0 μm. Intraoperative sarcomere length was measured at a single site with a laser diffraction device. Whole-muscle sarcomere length measurement was then determined by sampling across the muscle in the proximal, middle, and distal regions. Linear regression analysis and intraclass correlation coefficients were used to validate single intraoperative sarcomere lengths relative to whole-muscle sarcomere lengths. Results: Single intraoperative sarcomere lengths correlated strongly with average whole-muscle sarcomere length, although there was a systematic tendency to overestimate intraoperative sarcomere length. Intraoperative sarcomere length also matched well with all regions sampled, indicating that there was no tendency for intraoperative sarcomere length to better represent one region of the muscle compared with another. Conclusions: These results show that intraoperative sarcomere lengths accurately represent the entire muscle. The relatively small sarcomere length variations validate the use of intraoperative sarcomere length measurement during tendon transfer in which the entire muscle is not available for measurement because of limited surgical exposure. [Copyright &y& Elsevier]

Purpose: To quantify the gain in muscle mobility with progressive release of surrounding connective-tissue structures and to compare this property with the known architecture of each muscle. Methods: Each of 5 different muscle tendon units (extensor carpi radialis brevis, extensor carpi radialis longus, flexor carpi ulnaris, flexor digitorum superficialis, pronator teres) was released from its insertion and secured into the jaws of a clamp attached to a servomotor that could be operated under length or force control to simulate the load placed on the tendon by a surgical assistant. A constant load of 5 N was applied to the tendon while the muscle–tendon unit was released surgically from the surrounding tissue in 1-cm increments. Mobility was plotted against release distance and analyzed by linear regression to yield mobility gain, the slope of the regression equation. One-way analysis of variance was used to compare mobility gain among muscles. Results: In contrast to previous results from the brachioradialis muscle in which the mobility gain was large and highly nonlinear, mobility gain was small, consistent, and linear for all muscles studied. The smallest mobility gain was for the flexor digitorum superficialis and was highly linear. The largest gain was for the pronator teres and again was highly linear. In general, the mobility gain for the extensor carpi radialis brevis was similar to that of the extensor carpi radial longus. The flexor carpi ulnaris muscle was difficult to mobilize, and its gain was modest. There was no significant correlation between mobility gain of the forearm muscles during progressive release and the length of their fibers. Conclusions: The small mobility and complete lack of correlation with fiber length provide strong evidence that mobility gain does not accurately reflect muscle excursion as it is typically described. This calls into question the general practice of tensioning muscles by first passively extending the muscle and then choosing the attachment length as a particular portion of that passive relationship. Type of study/level of evidence: Prospective basic science. [Copyright &y& Elsevier]

Purpose: To show biomechanically that the brachioradialis (BR) muscle can be transferred to restore key pinch and forearm pronation simultaneously. Methods: Nine fresh-frozen forearms were thawed and instrumented with a custom muscle–tendon excursion jig. Maximum BR muscle–tendon excursion was measured with the wrist and thumb mobile. Muscle–tendon excursion then was measured from 60° of supination to 60° of pronation in 15° increments with the wrist and thumb fixed. Measurements were performed in 3 configurations: the native BR, the BR transferred volarly to the flexor pollicis longus (FPL) tendon, and the BR transferred dorsally (posterior to the radius) through the interosseous membrane to the FPL tendon. Muscle excursion–joint angle data were differentiated to compute pronation/supination moment arms. Two-way analyses of variance and post hoc Tukey tests were used to compare transfer conditions. Results: Maximum muscle excursion was nearly identical when volar and dorsal transfer conditions were compared. When pronation/supination motions were isolated, however, the volar transfer was associated with muscle shortening and small pronation moment arms through 30° ± 9° of supination. Importantly, the dorsal transfer was associated with muscle shortening and larger pronation moment arms through 28° ± 10° of pronation, a significant difference of 58.0° ± 16.0° compared to the traditional volar transfer. Conclusions: These data suggest that dorsal BR-to-FPL transfers can power key pinch and forearm pronation simultaneously even in the absence of other functional pronators. This transfer can be accomplished without changes to total muscle excursion compared with the traditional volar BR-to-FPL transfer. This result may enable the use of the BR-to-FPL transfer in patients who need key pinch but who lack functional pronation muscle groups (eg, ocular cutaneous 3). As result a larger patient population may benefit from the BR-to-FPL reconstructive procedure. [Copyright &y& Elsevier]

Objective: To compare the detailed architectural properties of the pronator teres (PT), extensor carpi radialis brevis (ECRB), and extensor pollicis longus (EPL) muscles to evaluate the suitability of PT-to-ECRB and PT-to-EPL surgical procedures. Methods: Muscle physiologic cross-sectional areas and region-specific muscle fiber lengths were measured in cadaveric PT, ECRB, and EPL muscles (n = 10 muscles of each type). One-way repeated-analyses of variance measures and post hoc t tests with Bonferroni corrections were used for statistical comparisons. Results: The ulnar head of the PT was present in 8 of 10 specimens. The average PT fiber length was similar to that of the ECRB (7.02 ± 0.49 cm vs 6.17 ± 0.27 cm) but was significantly longer than that of the EPL (5.44 ± 0.25 mm). Fiber length in the humeral head of the PT was longer compared with the ulnar head (7.19 ± 0.52 cm vs 4.14 ± 0.25 cm). The average physiologic cross-sectional area of the PT was similar to that of the ECRB (3.5 ± 0.4 cm2 vs 3.3 ± 0.3 cm2) but was significantly larger than that of the EPL (3.5 ± 0.4 cm2 vs 1.1 ± 0.1 cm2). Conclusions: From an architectural point of view the PT is an excellent donor choice for transfer to the ECRB for restoration of wrist extension or to the EPL for restoration of thumb extension. Because there is fiber length heterogeneity within the PT, however, when the ulnar head is present it may limit the total excursion of the donor muscle. These data suggest that releasing the ulnar head of the PT before transfer may result in larger excursions of this important motor in tendon transfer surgery. [Copyright &y& Elsevier]

Tendon transfer surgery restores function by rerouting working muscle–tendon units to replace the function of injured or paralyzed muscles. This procedure requires mobilizing a donor muscle relative to its surrounding myofascial connections, which improves the muscle's new line of action and increases excursion. However, the biomechanical effect of mobilization on a donor muscle's force-generating function has not been previously studied under in vivo conditions. The purpose of this study was to quantify the effect of surgical mobilization on active and passive biomechanical properties of 3 large rabbit hind limb muscles. Myofascial connections were mobilized stepwise from the distal end to the proximal end of muscles (0%, 25%, 50%, and 75% of muscle length) and their active and passive length-tension curves were measured after each degree of mobilization. Second toe extensor, a short-fibered muscle, exhibited a 30% decline in peak stress and 70% decline in passive stress, whereas extensor digitorum longus, a short-fibered muscle, and tibialis anterior, a long-fibered muscle, both exhibited similar smaller declines in active (about 18%) and passive stress (about 65%). The results highlight 3 important points: (1) a trade-off exists between increasing muscle mobility and decreasing force-generating capacity; (2) intermuscular force transmission is important, especially in second toe extensor, because it was able to generate 70% of its premobilization active force although most fibers were freed from their native origin; and (3) muscle architecture is not the major influence on mobilization-induced force impairment. These data demonstrate that surgical mobilization itself alters the passive and active force-generating capacity of skeletal muscles. Thus, surgical mobilization should not be viewed simply as a method to redirect the line of action of a donor muscle because this procedure has an impact on the functional properties of the donor muscle itself. [ABSTRACT FROM AUTHOR]

A letter is presented about a prospective series of patients who were treated with three-day ambulatory perineural local anesthetic infusion in addition to the customary single-injection brachial plexus block for shoulder manipulation. An electronic portable infusion pump was used to administer the infusions at home. The ambulatory continuous interscalene nerve block improved both short- and long-term outcomes following shoulder manipulation for refractory adhesive capsulitis.

The article presents a case study of a 65 year old man with a complaint of new-onset low back pain, bilateral foot numbness, and left lower extremity radicular symptoms with foot drop. Topics include patient's magnetic resonance images revealing complete fatty replacement of the erector spine musculature throughout the lumbar spine; and patient's lower extremity symptoms were consistent with radiculopathy, and the magnetic resonance images indicating mild to moderate central canal stenosis.

Purpose Simple decompression and anterior subcutaneous transposition are effective surgical interventions for cubital tunnel syndrome and yield similarly favorable outcomes. However, a substantial proportion of patients demonstrate unsatisfactory outcomes for reasons that remain unclear. We compared effects of decompression and transposition on regional ulnar nerve strain to better understand the biomechanical impacts of each strategy. Methods Patients diagnosed with cubital tunnel syndrome and scheduled for anterior subcutaneous transposition surgery were enrolled. Simple decompression, circumferential decompression, and anterior transposition of the ulnar nerve were performed during the course of the transposition procedure. Regional ulnar nerve strain around the elbow was measured for each surgical intervention based on 4 wrist and elbow joint configurations. Results With elbow extension at 180°, both circumferential decompression and anterior transposition resulted in approximately 68% higher nerve strains than simple decompression. Conversely, with elbow flexion, simple decompression resulted in higher average strains than anterior transposition. Limited regional differences in strain were observed for any surgical intervention with elbow extension. However, with elbow flexion, strains were higher in distal and central regions compared with the proximal region within all surgical groups, and proximal region strain was higher after simple decompression compared with anterior transposition. Conclusions As predicted by the altered anatomic course, anterior transposition results in lower ulnar nerve strains than simple decompression during elbow flexion and higher nerve strains during elbow extension. Irrespective of anatomic course, circumferential release of paraneurial tissues may also influence nerve strain. Nerve strain varies regionally and is influenced by surgery and joint configuration. Clinical relevance Our data provide insight into how surgery resolves and redistributes traction on the ulnar nerve. These findings may help inform which surgical procedure to perform for a specific patient, guide rehabilitation protocols, and suggest regions of anatomic concern during index and revision surgery. [ABSTRACT FROM AUTHOR]