Use of an instrumented dual-task timed up and go test in children with traumatic brain injury.

BACKGROUND: Wearable sensors have allowed researchers to instrument tests of gait-related mobility, including the widely used timed 'up-and-go' test (TUG). Currently, there is a lack of instrumented test data on whether children with moderate to severe traumatic brain injury (TBI) perform differently on the TUG compared to typically developed (TD) controls during a cognitive-motor task. RESEARCH QUESTION: The aim was to explore the effects of a cognitive-motor task on TUG subcomponents among children with TBI compared to TD children. METHODS: This observational cross-sectional study included 12 children with moderate to severe TBI (6 males and 6 females, age 10.5 ±â€¯1.5 years of age) and 10 age and sex-matched TD controls (5 males and 5 females, 10.4 ±â€¯1.3 years of age). Each participant completed 6 trials of the TUG wearing a single inertial measurement unit sensor at a self-selected walking pace while listening to an array of 10 randomly presented single digits during each TUG trial. RESULTS: Total time to complete the TUG was not significantly different between groups. The cognitive-motor task led to significantly lower mean turn and peak turn angular velocity values during the turn-around-the-cone and turn-before-sitting TUG subcomponents in children with TBI compared to the TD controls (p ≤ 0.05). Additionally, the cognitive-motor task led to significantly lower values for maximum torso flexion to extension angle, peak flexion and extension angular velocity and peak vertical acceleration for the sit-to-stand subcomponent (p < 0.05). Peak flexion angular velocity during the stand-to-sit subcomponent was lower for the TBI group compared to the children with TD (p < 0.05). SIGNIFICANCE: The study provides new insights into the performance of complex gait-related mobility tasks in the context of an instrumented TUG among children with moderate to severe TBI. Our results highlight the potential benefits of outfitting pediatric inpatients with an IMU while completing the TUG.

Electronically augmented gait abnormality assessment following lower extremity trauma.

BACKGROUND: Objective evaluation of patient outcomes has become an essential component of patient management. Along with patient-reported outcomes, performance-based measures (PBMs) such as gait analysis are an important part of this evaluation. The purpose of this study was to evaluate the validity of utilizing a wearable inertial measurement unit (IMU) in an outpatient clinic setting to assess its ability to provide clinically relevant data in patients with altered gait resulting from lower extremity trauma. METHODS: Five orthopaedic trauma patients with varying degrees of gait pathologies were compared to 5 healthy control subjects. Kinematic data were simultaneously recorded by the IMU and a gold standard Vicon video motion analysis system (Vicon Motion Systems Ltd, Oxford, UK) during a modified 10-m walk test. Raw data captured by the IMU were directly compared to Vicon data. Additionally, 5 objective gait parameters were compared for controls and the 5 trauma patients. RESULTS: The IMU data streams strongly correlated with Vicon data for measured variables used in the subsequent gait analysis: vertical acceleration, vertical displacement, pitch angular velocity, and roll angular velocity (Pearson r-value > 0.9 for all correlations). Quantitative kinematic data in post-trauma patients significantly differed from control data and correlated with observed gait pathology. CONCLUSIONS: When compared to the gold standard motion capture reference system (Vicon), an IMU can reliably and accurately measure clinically relevant gait parameters and differentiate between normal and pathologic gait patterns. This technology is easily integrated into clinical settings, requires minimal time, and represents a performance-based method for quantifiably assessing gait outcomes. LEVEL OF EVIDENCE: Diagnostic Level 1.

Reliability of the sub-components of the instrumented timed up and go test in ambulatory children with traumatic brain injury and typically developed controls.

BACKGROUND: Studies have evaluated the test-re-test reliability of subcomponents of the timed up and-go test in adults by using body-worn inertial sensors. However, studies in children have not been reported in the literature. RESEARCH QUESTION: To evaluate the within-session reliability of subcomponents of a newly developed electronically augmented timed 'upand-go' test (EATUG) in ambulatory children with traumatic brain injury (TBI) and children with typical development (TD). METHOD: The timed up and go test was administered to twelve consecutive ambulatory children with moderate to severe TBI (6 males and 6 females, age 10.5 ±â€¯1.5 years, range 8-13 years, during inpatient rehabilitation at 27.0 ±â€¯11.8 days following injury) and 10 TD age and sex-matched children (5 males and 5 females, 10.4 ±â€¯1.3 years, range 8-11 years). Participants wore a single chest-mounted inertial measurement sensor package with custom software that measured angular and acceleration velocity and torso flexion and extension angles, while they performed 6 trials of the EATUG test. Measures were derived from the overall time to complete the TUG test, angular velocity and angular displacement data for torso flexion and extension during sit-to-stand and stand-to-sit segments and both mean and peak angular velocities for two turning segments (i.e. turning around a cone and turning-before-sitting). RESULTS: Within-session reliability of the subcomponents of the TUG test for children with TBI assessed by the intra-class correlation coefficient was ICC (1,1) = 0.84, (range 0.82-0.96), and for TD children ICC (1,1) = 0.73, (range 0.53-0.89). Scores on Total Time, maximum torso flexion/extension angle and peak flexion angular velocity during sit-tostand, and peak turn angular velocity for both turns around the cone and turns before sitting were lower for children with TBI than for TD children (p ≤ 0.05). SIGNIFICANCE: The EATUG test is a reliable measure of physical function in children with TBI who are being discharged from inpatient rehabilitation.

Biceps Tenodesis: Biomechanical Assessment of 3 Arthroscopic Suprapectoral Techniques.

Biceps tenodesis maintains the cosmetic appearance and length-tension relationship of the biceps with an associated predictable clinical outcome compared with tenotomy. Arthroscopic suprapectoral techniques are being developed to avoid the disadvantages of the open subpectoral approach. This study biomechanically compared 3 arthroscopic suprapectoral biceps tenodesis techniques performed with a suture anchor with lasso loop technique, an interference screw, and a compressive rivet. For a total of 15 randomized paired tests, 15 pairs of human cadaveric shoulders were used to test 1 technique vs another 5 times with 3 customized setups. Biomechanical testing was performed with an electromechanical testing system. The tendon was preloaded with 10 N and cyclically loaded at 0 to 40 N for 50 cycles. Load to failure testing was performed at 1 mm/s until failure occurred. The compressive rivet, interference screw, and suture anchor with lasso loop had mean load to failure of 97.1 N, 146.4 N, and 157.6 N, respectively. The difference in ultimate strength between the suture anchor with lasso loop and the compressive rivet was statistically significant (P=.04). No significant differences were found between the suture anchor with lasso loop and the interference screw (P=.93) or between the interference screw and the rivet (P=.10). When adjusted for sex, the load to failure overall among the 3 constructs was not significantly different. All 3 techniques had a different predominant mechanism of failure. The suture anchor with lasso loop showed superior load to failure compared with the compressive rivet. The minimum load to failure required to achieve clinically reliable biceps tenodesis is unknown. [Orthopedics. 2017; 40(6):e1009-e1016.].

Kartogenin with PRP promotes the formation of fibrocartilage zone in the tendon-bone interface.

Treatment of tendon-bone junction injuries is a challenge because tendon-bone interface often heals poorly and the fibrocartilage zone, which reduces stress concentration, at the interface is not formed. In this study, we used a compound called kartogenin (KGN) with platelet-rich plasma (PRP) to induce the formation of fibrocartilage zone in a rat tendon graft-bone tunnel model. The experimental rats received KGN-PRP or PRP injections in the tendon graft-bone tunnel interface. The control group received saline. After 4, 8 and 12 weeks, Safranin O staining of the tendon graft-bone tunnels revealed abundant proteoglycans in the KGN-PRP group indicating the formation of cartilage-like transition zone. Immunohistochemical and immuno-fluorescence staining revealed collagen types I (Col-I) and II (Col-II) in the newly formed fibrocartilage zone. Both fibrocartilage zone formation and maturation were healing time dependent. In contrast, the PRP and saline control groups had no cartilage-like tissues and minimal Col-I and Col-II staining. Some gaps were also present in the saline control group. Finally, pull-out strength in the KGN-PRP-treated group at 8 weeks was 1.4-fold higher than the PRP-treated group and 1.6-fold higher than the saline control group. These findings indicate that KGN, with PRP as a carrier, promotes the formation of fibrocartilage zone between the tendon graft and bone interface. Thus, KGN-PRP may be used as a convenient cell-free therapy in clinics to promote fibrocartilage zone formation in rotator calf repair and anterior cruciate ligament reconstruction, thereby enhancing the mechanical strength of the tendon-bone interface and hence the clinical outcome of these procedures. Copyright © 2017 John Wiley & Sons, Ltd.

The effect of arthroscopic suture passing instruments on rotator cuff damage and repair strength.

There are a variety of arthroscopic devices used to pass sutures through the rotator cuff for its repair. Because they vary in size and shape, it is possible that they could damage the cuff and affect the integrity of the repair. We chose four devices for assessment--SutureLasso (Arthrex, Naples, FL), straight BirdBeak (Arthrex, Naples, FL), Viper (Arthrex, Naples, FL), and a #7 tapered Mayo needle--and performed cuff reattachments in four paired shoulders using suture anchors. These repairs were cycled and tested to failure. The SutureLasso and Mayo needle repairs failed at approximately 285 N whereas the BirdBeak and Viper failed during cycling at 150 N. It appears that the devices, which made the bigger holes in the cuff, can compromise the integrity of the repair.

Long head biceps tenotomy versus tenodesis: a cadaveric biomechanical analysis.

PURPOSE: Treatment of pathology of the long head biceps (LHB) tendon has become an area of renewed interest among orthopaedic surgeons in recent years. Numerous authors have recommended tenotomy, whereas others have recommended tenodesis to avoid distal migration of the LHB tendon stump and the associated cosmetic deformity that may develop. The purpose of the present study was to determine the likelihood of distal migration from the bicipital groove of the long head biceps tendon after tenotomy under physiologic loading conditions and the ultimate load to failure for tenotomized LHB tendons, and to compare these values with those present after tenodesis with an interference screw in a cadaveric model. TYPE OF STUDY: Anatomic cadaveric biomechanical study. METHODS: Cyclic loading was performed on 10 cadaveric shoulders through the LHB tendon on an MTS machine (Materials Testing System; MTS Systems Corp, Minneapolis, MN) at a peak force of 50 N (loading rate of 100 N/second) for 200 cycles. After cyclic loading, the specimens were tested to failure at a loading rate of 100 N/second. Failure was defined as migration of the biceps stump distal to the bicipital groove on the proximal humerus. The LHB tendon was then passed back up the bicipital groove and tenodesis was performed in the groove with a bioabsorbable interference screw according to a previously described technique (Arthrex, Naples, FL). Cyclic and load to failure testing were then repeated in similar fashion and the values were recorded and compared with those of the tenotomized subjects (n = 10 in each group). RESULTS: Four of 10 tenotomized specimens (40%) failed during cyclic loading, with the average number of cycles to failure being 35. The other 6 specimens passed the cyclic test. The average ultimate load to failure in these specimens was 110.7 N. After biceps tenodesis, all specimens passed the cyclic loading test. The average ultimate load to failure in these 10 specimens was 310.8 N. Compared with the 6 tenotomized specimens that passed the cyclic test, the specimens that underwent tenodesis had a significantly higher pullout strength (ultimate strength) with P = .001. CONCLUSIONS: These results show that, compared with tenodesis, biceps tenotomy results in a significant risk of distal LHB tendon migration and significantly lower load to failure. Cyclic loads similar to those produced by gentle active range of motion without resistance resulted in failure in 40% of specimens tested after an average of 35 cycles. Based on these results, the authors recommend that LHB tenodesis be considered in any patient who may object to the cosmetic deformity and associated dysfunction produced by distal LHB tendon migration after tenotomy. CLINICAL RELEVANCE: The findings of this study help determine whether to perform long head biceps tenotomy or tenodesis when dealing with long head biceps tendon pathology.

Sclerostin inhibition prevents spinal cord injury-induced cancellous bone loss.

Spinal cord injury (SCI) results in rapid and extensive sublesional bone loss. Sclerostin, an osteocyte-derived glycoprotein that negatively regulates intraskeletal Wnt signaling, is elevated after SCI and may represent a mechanism underlying this excessive bone loss. However, it remains unknown whether pharmacologic sclerostin inhibition ameliorates bone loss subsequent to SCI. Our primary purposes were to determine whether a sclerostin antibody (Scl-Ab) prevents hindlimb cancellous bone loss in a rodent SCI model and to compare the effects of a Scl-Ab to that of testosterone-enanthate (TE), an agent that we have previously shown prevents SCI-induced bone loss. Fifty-five (n = 11-19/group) skeletally mature male Sprague-Dawley rats were randomized to receive: (A) SHAM surgery (T8 laminectomy), (B) moderate-severe (250 kilodyne) SCI, (C) 250 kilodyne SCI + TE (7.0 mg/wk, im), or (D) 250 kilodyne SCI + Scl-Ab (25 mg/kg, twice weekly, sc) for 3 weeks. Twenty-one days post-injury, SCI animals exhibited reduced hindlimb cancellous bone volume at the proximal tibia (via µCT and histomorphometry) and distal femur (via µCT), characterized by reduced trabecular number and thickness. SCI also reduced trabecular connectivity and platelike trabecular structures, indicating diminished structural integrity of the remaining cancellous network, and produced deficits in cortical bone (femoral diaphysis) strength. Scl-Ab and TE both prevented SCI-induced cancellous bone loss, albeit via differing mechanisms. Specifically, Scl-Ab increased osteoblast surface and bone formation, indicating direct bone anabolic effects, whereas TE reduced osteoclast surface with minimal effect on bone formation, indicating antiresorptive effects. The deleterious microarchitectural alterations in the trabecular network were also prevented in SCI + Scl-Ab and SCI + TE animals, whereas only Scl-Ab completely prevented the reduction in cortical bone strength. Our findings provide the first evidence indicating that sclerostin inhibition represents a viable treatment to prevent SCI-induced cancellous and cortical bone deficits and provides preliminary rationale for future clinical trials focused on evaluating whether Scl-Ab prevents osteoporosis in the SCI population.

Rotator cuff repair. A biomechanical comparison of three techniques.

BACKGROUND: The most common complication of rotator cuff repair is structural failure at the repair site. A single-layer repair does not adequately reproduce the anatomic insertion and may not optimize fixation strength. HYPOTHESIS: A double-layer rotator cuff repair will have greater initial fixation strength than a single-layer repair. STUDY DESIGN: Controlled laboratory study. METHODS: Twelve fresh-frozen matched pairs of cadaveric shoulders were repaired by using dual-site fixation with both suture anchors and transosseous tunnels on one side (technique 1). Fixation was achieved by using suture anchors with horizontal mattress sutures and bone tunnels with modified Mason-Allen sutures. Half of the contralateral matched shoulders underwent fixation with suture anchors and simple sutures to simulate commonly used arthroscopic methods (technique 2) and, in the rest, fixation was achieved by using transosseous tunnels and modified Mason-Allen sutures (technique 3). Repaired specimens then underwent cyclic loading at physiologic rates and loads. The number of cycles to failure, which was defined as a 1-cm gap at the repair site, was then recorded. An arbitrary cut-off point of 5000 cycles was chosen. RESULTS: The mean number of cycles to failure with technique 1 (3694 +/- 1980 cycles) was significantly greater than that with either technique 2 (1414 +/- 1888 cycles) or technique 3 (528 +/- 683 cycles). Failure was predominantly through bone. CONCLUSIONS: The initial fixation strength of our double-layer repair exceeds that of isolated single-layer repairs with either suture anchors or transosseous tunnels.

The effects of thermal capsulorrhaphy and rotator interval closure on multidirectional laxity in the glenohumeral joint: a cadaveric biomechanical study.

PURPOSE: Arthroscopic rotator interval closure has been advocated to supplement the stabilization provided by thermal capsulorrhaphy for glenohumeral instability. However, no basic science study has examined the separate and combined effects of thermal capsulorrhaphy and rotator interval closure on the multiplane laxity of the glenohumeral joint. The purpose of this study was to measure the effects of isolated and combined thermal capsulorrhaphy and rotator interval closure on anterior, posterior, and inferior glenohumeral joint laxity in a cadaveric model. TYPE OF STUDY: Anatomic biomechanical study. METHODS: Ten cadaveric shoulders were fixed to a biomechanical testing apparatus and 5.5 lb (25 N) of force was applied to the humeral head in anterior, posterior, and inferior directions in a random order. Translation was measured in each direction on the untreated specimen (U), after arthroscopic rotator interval closure (R), after thermal capsulorrhaphy (T), and after combined rotator interval closure and thermal capsulorrhaphy (RT) with a transducer attached to a computer via data acquisition software and A/D board. Values for anterior, posterior, and inferior translation were thus obtained for U, R, T, and RT. RESULTS: Average translations in the anterior direction for the U, R, T, and RT groups were 8.0 +/- 4.4 mm, 6.7 +/- 3.3 mm, 8.5 +/- 3.6 mm, and 7.8 +/- 2.2 mm, respectively. Average translations in the posterior direction were 6.9 +/- 3.3 mm (U), 5.9 +/- 3.4 mm (R), 7.9 +/- 4.7 mm (T), and 6.8 +/- 4.0 mm (RT). Average translations in the inferior plane were 4.9 +/- 4.7 mm (U), 3.6 +/- 3.7 mm (R), 3.7 +/- 3.3 mm (T), and 2.4 +/- 1.6 mm (RT). Rotator interval closure decreased anterior, posterior, and inferior translation by 17%, 15%, and 28%, respectively, versus the untreated subjects. Thermal capsulorrhaphy increased anterior and posterior translation by 5% and 13% and decreased inferior translation by 25% versus untreated subjects. Combined RT decreased anterior, posterior, and inferior translation by 4%, 2%, and 52%, respectively. Statistical analysis revealed that rotator interval closure significantly decreased laxity values in all planes, whereas thermal capsulorrhaphy did not significantly alter laxity values versus untreated subjects. CONCLUSIONS: Isolated rotator interval closure decreased glenohumeral laxity in all directions tested, particularly inferior translation. Thermal capsulorrhaphy actually increased anterior and posterior translation in these subjects while decreasing inferior translation. We believe the trends seen reflect the clinical efficacy of rotator interval closure in the treatment of multidirectional instability. This procedure has the potential to provide improved stability versus thermal capsulorrhaphy alone, and may be considered as a supplement to or substitute for thermal capsulorrhaphy in patients with multidirectional instability. CLINICAL RELEVANCE: When treating glenohumeral instability with arthroscopic techniques, rotator interval closure may enhance stability to a greater degree than thermal capsulorrhaphy without its associated risks.

Electromyographic analysis of the rotator cuff and deltoid musculature during common shoulder external rotation exercises.

STUDY DESIGN: Prospective single-group repeated-measures design. OBJECTIVES: To quantify electromyographic (EMG) muscle activity of the infraspinatus, teres minor, supraspinatus, posterior deltoid, and middle deltoid during exercises commonly used to strengthen the shoulder external rotators. BACKGROUND: Exercises to strengthen the external rotators are commonly prescribed in rehabilitation, but the amount of EMG activity of the infraspinatus, teres minor, supraspinatus, and deltoid during these exercises has not been thoroughly studied to determine which exercises would be most effective to achieve strength gains. METHODS AND MEASURES: EMG measured using intramuscular electrodes were analyzed in 10 healthy subjects during 7 shoulder exercises: prone horizontal abduction at 100 degrees of abduction and full external rotation (ER), prone ER at 90 degrees of abduction, standing ER at 90 degrees of abduction, standing ER in the scapular plane (45 degrees abduction, 30 degrees horizontal adduction), standing ER at 0 degrees of abduction, standing ER at 0 degrees of abduction with a towel roll, and sidelying ER at 0 degrees of abduction. The peak percentage of maximal voluntary isometric contraction (MVIC) for each muscle was compared among exercises using a 1-way repeated-measures analysis of variance (P<.05). RESULTS: EMG activity varied significantly among the 7 exercises. Sidelying ER produced the greatest amount of EMG activity for the infraspinatus (62% MVIC) and teres minor (67% MVIC). The greatest amount of activity of the supraspinatus (82% MVIC), middle deltoid (87% MVIC), and posterior deltoid (88% MVIC) was observed during prone horizontal abduction at 100 degrees with full ER. CONCLUSIONS: Results from this study provide initial information to develop rehabilitation programs. It also provides information helpful for the design and conduct of future studies.

Biomechanics of the elbow in sports.

In throwing activities, the elbow is sometimes stressed to its biomechanical limits. In this article, forces, torques, angular velocities, and muscle activity about the elbow are reviewed for the baseball pitch, the football pass, the javelin throw, the windmill softball pitch, the tennis serve, and the golf swing. The elbow goes through rapid extension in baseball pitching (about 2400 degrees/s) and rapid flexion in the javelin throw (about 1900 degrees/s). During baseball pitching, the elbow joint is subject to a valgus torque reaching 64 Nm, and requires proximal forces as high as 1000 N to prevent elbow distraction. The ulnar collateral ligament (UCL) rupture in baseball pitching, lateral epicondylitis in the tennis backhand, and other injury mechanisms are also discussed.

Influence of aromatase inhibition on the bone-protective effects of testosterone.

The influence of the aromatase enzyme in androgen-induced bone maintenance after skeletal maturity remains somewhat unclear. Our purpose was to determine whether aromatase activity is essential to androgen-induced bone maintenance. Ten-month-old male Fisher 344 rats (n = 73) were randomly assigned to receive Sham surgery, orchiectomy (ORX), ORX + anastrozole (AN; aromatase inhibitor), ORX + testosterone-enanthate (TE, 7.0 mg/wk), ORX + TE + AN, ORX + trenbolone-enanthate (TREN; nonaromatizable, nonestrogenic testosterone analogue; 1.0 mg/wk), or ORX + TREN + AN. ORX animals exhibited histomorphometric indices of high-turnover osteopenia and reduced cancellous bone volume compared with Shams. Both TE and TREN administration suppressed cancellous bone turnover similarly and fully prevented ORX-induced cancellous bone loss. TE- and TREN-treated animals also exhibited greater femoral neck shear strength than ORX animals. AN co-administration slightly inhibited the suppression of bone resorption in TE-treated animals but did not alter TE-induced suppression of bone formation or the osteogenic effects of this androgen. In TREN-treated animals, AN co-administration produced no discernible effects on cancellous bone turnover or bone volume. ORX animals also exhibited reduced levator ani/bulbocavernosus (LABC) muscle mass and elevated visceral adiposity. In contrast, TE and TREN produced potent myotrophic effects in the LABC muscle and maintained fat mass at the level of Shams. AN co-administration did not alter androgen-induced effects on muscle or fat. In conclusion, androgens are able to induce direct effects on musculoskeletal and adipose tissue, independent of aromatase activity.

Posterior olecranon resection and ulnar collateral ligament strain.

Valgus extension overload is well described in the throwing athlete. The surgical treatment involves posterior olecranon osteophyte resection. It is not known how much of the posterior olecranon can be resected before increased stress is placed on the ulnar collateral ligament. Ten cadaveric arms underwent posterior olecranon resection in 4-mm increments. After each bone resection, three different valgus loads were applied to the elbow at 70 degrees and 90 degrees of flexion. Ulnar collateral ligament strain significantly increased with each load. Significantly more strain occurred on the ulnar collateral ligament at 90 degrees compared with 70 degrees of elbow flexion. This difference may be the result of the relative importance of the ulnar collateral ligament and the posterior olecranon at different positions of elbow flexion. The strain on the ulnar collateral ligament was slightly higher after the 8-mm and 12-mm cuts but not statistically significant. This study suggests that at moderate quasistatic valgus loads, ulnar collateral ligament strain is not significantly increased with posterior olecranon resection.