The effect of subscapularis muscle contraction on coaptation of anteroinferior glenohumeral ligament–labrum complex after Bankart repair

Facilitation of healing is important for the anteroinferior glenohumeral ligament–labrum complex (AIGHL-LC) after Bankart repair in shoulder dislocation. The purpose of this study was to investigate the effect of subscapularis muscle loading on contact area and contact pressure between the subscapularis and AIGHL-LC and between the glenoid bone and the AIGHL-LC following Bankart repair. Twenty-two fresh-frozen cadaveric shoulders were used. They were attached to a shoulder-positioning device to which a compression force was applied. Loads applied to the supraspinatus, infraspinatus, and teres minor tendons were held constant. The loads applied to the subscapularis tendon were set at 0, 10, 20, and 30 Newton (N). Contact pressure and area between the subscapularis and the AIGHL-LC were measured with the arm at 4 rotational positions: 60° and 30° internal, neutral, and 30° external. After the Bankart lesion was created, the contact area and pressure between the AIGHL-LC and glenoid bone were measured while Bankart repair was performed with or without loading of the subscapularis. The contact area and pressures with 10, 20, and 30 N of subscapularis loadings were significantly greater than with 0 N of subscapularis loading at 60° internal rotation and 30° external rotation (P < .05). After Bankart repair, contact area and pressure with subscapularis loading between the AIGHL-LC and glenoid bone were significantly greater than without subscapularis loading (P < .01). We conclude that isometric contraction exercises of the subscapularis might facilitate healing of the AIGHL-LC after Bankart repair.     

前哨淋巴结活检术联合保乳治疗对早期乳腺癌患者临床疗效、术后并发症及肩关节功能的影响

目的:探讨前哨淋巴结活检术联合保乳治疗对早期乳腺癌患者临床疗效、术后并发症及肩关节功能的影响。方法:选取2014年10月至2017年2月就诊于我院的乳腺癌患者,按照患者手术方式分为联合组与对照组,其中联合组行前哨淋巴结活检手术联合保乳治疗,对照组行传统腋窝淋巴结清扫术治疗,每组各选取50例,随访时间为6个月。比较两组手术情况、并发症、乳腺美容效果及肩关节功能情况。结果:联合组手术时间、总出血量、引流管拔除时间、总引流量均明显低于对照组(P0.05)。手术治疗后,联合组并发症比例为6%,明显低于对照组38%。术后,两组患者随访6个月,联合组乳腺美容效果明显高于对照组(P0.05)。术前,两组肩关节功能各指标水平比较差异不显著(P0.05);术后,两组肩关节屈曲活动度、外旋活动度、后伸活动度、外展活动度相较于术前均明显降低(P0.05),联合组内旋活动度相较于术前降低不显著(P0.05),而对照组内旋活动度相较于术前降低显著(P0.05)。术后,联合组肩关节屈曲活动度、外旋活动度、内旋活动度、后伸活动度、外展活动度均显著高于对照组(P0.05)。结论:前哨淋巴结活检术联合保乳治疗早期乳腺癌创伤小,美容效果明显,可显著降低术后并发症发生率并减轻对患者肩关节功能的损害,远期疗效仍有待于进一步随访观察。     

肩关节镜下Bankart合并Remplissage手术治疗创伤性肩关节脱位的效果研究

目的:探讨采用肩关节镜下Bankart合并Remplissage手术治疗创伤性肩关节脱位的患者的临床疗效,为创伤性复发性肩关节脱位的临床治疗提供参考依据。方法:回顾性分析2014年12月-2016年12月就诊于吉林市中心医院的创伤性复发性肩关节脱位的52例患者住院期间的临床资料,均采用Bankart合并Remplissage手术治疗。临床疗效分析采用重复测量资料的方差分析以确定手术治疗的单独效用。结果:术后4个月和6个月,患者的Rowe评分和Constant-Murley评分均高于术前(P0.05);患者术后的VAS评分较术前明显所降低(P0.05),但术后关节活动度(肩关节平均前屈上举角度和平均外展90度外旋角度)的改变无统计学差异(P0.05);所有患者在术后6个月内未出现术后再脱位、半脱位现象。结论:Bankart修复联合Remplissage术对创伤性复发性肩关节前脱位患者的治疗具有较好的临床效果,可显著降低复发率。     

Comparison of two trunk electromagnetic sensor placement methods during shoulder motion analysis

For kinematic studies of the shoulder, electromagnetic sensors are commonly placed on the humerus, scapula, and trunk. The trunk sensor is used to describe humeral and scapular kinematics with respect to the trunk. There are two common trunk sensor placements, the sternum or third thoracic vertebrae (T3). It is currently unclear if placement of the trunk sensor affects kinematics, making it difficult to compare data across studies. The purpose of this study was to compare two trunk sensor placements (T3 and sternum) on trunk and scapular kinematics during arm elevation. An electromagnetic tracking system was used to collect kinematic data during five consecutive repetitions of ascending and descending arm elevation in the sagittal plane. The results indicate that trunk sensor placement had no significant effect on trunk kinematics or scapular upward/downward rotation and internal/external rotation. Scapular anterior/posterior tilt was significantly greater when the trunk sensor was on the sternum compared to the T3 vertebrae during ascending 30°–120°: mean difference = −3.51° (95%CI: −5.61, −1.40), and descending 120°–30°: mean difference = −3.27° (95%CI: −6.07, −0.48). However, the difference in anterior/posterior tilt did not exceed the error (minimal detectable change), and thus is likely not a meaningful difference. These results indicate the trunk sensors can be affixed on T3 or the sternum, depending on the needs of the study.     

Simulated activities of daily living do not replicate functional upper limb movement or reduce movement variability

Kinematic assessments of the upper limb during activities of daily living (ADLs) are used as an objective measure of upper limb function. The implementation of ADLs varies between studies; whilst some make use of props and define a functional target, others use simplified tasks to simulate the movements in ADLs. Simulated tasks have been used as an attempt to reduce the large movement variability associated with the upper limb. However, it is not known whether simulated tasks replicate the movements required to complete ADLs or reduce movement variability. The aim of this study is to evaluate the use of simulated tasks in upper limb assessments in comparison to functional movements. Therefore answering the following questions: Do simulated tasks replicate the movements required of the upper limb to perform functional activities? Do simulated tasks reduce intra- and inter-subject movement variability? Fourteen participants were asked to perform five functional tasks (eat, wash, retrieve from shelf, comb and perineal care) using two approaches: a functional and a simulated approach. Joint rotations were measured using an optoelectronic system. Differences in movement and movement variability between functional and simulated tasks were evaluated for the thorax, shoulder, elbow/forearm and wrist rotations. Simulated tasks did not accurately replicate the movements required for ADLs and there were minimal differences in movement variability between the two approaches. The study recommends the use of functional tasks with props for future assessments of the upper limb.     

关节镜下肩峰成形术治疗肩峰撞击征的临床效果观察

目的:探讨通过关节镜下肩峰成形术治疗肩峰撞击症的临床效果。方法:选择36例肩峰撞击症患者为研究对象,给予关节镜下肩峰成形术治疗,比较治疗前后患者的Constant-Murley肩关节功能评分。结果:36例患者均术后随访15~24个月,平均18个月。术前Constant-Murley肩关节功能评分平均38.2分,术后末次随访平均评分为88.1分,较术前显著升高,差异有统计学意义(P0.05),且患者术后末次随访时疼痛、日常生活活动、主动活动范围及肌力评分均显著高于术前,差异均有统计学意义(P0.05)。结论:关节镜下肩峰成形术能有效治疗肩峰撞击症,明显减轻患者的痛苦,改善患者的生活质量,值得临床推广。     

Kinematic and EMG analysis of horizontal bimanual climbing in humans

Climbing is an increasingly popular recreational and competitive behavior, engaged in a variety of environments and styles. However, injury rates are high in climbing populations, especially in the upper extremity and shoulder. Despite likely arising from an arboreal, climbing ancestor and being closely related to primates that are highly proficient climbers, the modern human shoulder has devolved a capacity for climbing. Limited biomechanical research exists on manual climbing performance. This study assessed kinematic and muscular demands during a bimanual climbing task that mimicked previous work on climbing primates. Thirty participants were recruited – 15 experienced and 15 inexperienced climbers. Motion capture and electromyography (EMG) measured elbow, thoracohumeral and trunk angles, and activity of twelve shoulder muscles, respectively, of the right-side while participants traversed across a horizontal climbing apparatus. Statistical parametric mapping was used to detect differences between groups in kinematics and muscle activity. Experienced climbers presented different joint motions that more closely mimicked the kinematics of climbing primates, including more elbow flexion (p = 0.0045) and internal rotation (p = 0.021), and less thoracohumeral elevation (p = 0.046). Similarly, like climbing primates, experienced climbers generally activated the shoulder musculature at a lower percentage of maximum, particularly during the exchange from support to swing and swing to support phase. However, high muscle activity was recorded in all muscles in both participant groups. Climbing experience coincided with a positive training effect, but not enough to overcome the high muscular workload of bimanual climbing. Owing to the evolved primary usage of the upper extremity for low-force, below shoulder-height tasks, bimanual climbing may induce high risk of fatigue-related musculoskeletal disorders.     

Validation of imaging-based quantification of glenohumeral joint kinematics using an unmodified clinical biplane fluoroscopy system

Model-based tracking, using CT and biplane fluoroscopy, allows highly accurate quantification of glenohumeral motion and changes in the subacromial space. Previous investigators have used custom-built biplane fluoroscopes designed specifically for kinematic applications, which are available at few institutions and require FDA approval prior to clinical use. The aim of this study was to demonstrate the utility of an off-the-shelf clinical biplane fluoroscope for kinematic applications by validating model-based tracking for measurement of glenohumeral motion using an unmodified clinical system. Biplane images of each shoulder of a cadaver torso were acquired at various joint positions and during simulated movements along anatomical planes of motion. The pose of each humerus and scapula was determined using model-based tracking and compared to a bead-based gold standard. Error due to a temporal-offset between corresponding biplane images, characteristic of clinical biplane systems, was determined by comparison of measured and known relative position of 2 bead clusters of a phantom that was imaged while moved throughout the fluoroscopy image volume. Model-based tracking had global kinematic mean absolute errors of 0.27 mm and 0.29° (static), and 0.22–0.32 mm and 0.12–0.45° (dynamic). Glenohumeral mean absolute errors were 0.39 mm and 0.45° (static), and 0.36–0.42 mm and 0.41–0.48° (dynamic). The temporal-offset was predicted to add errors of 0.06–0.85 mm and 0.05–0.28° for cadaveric trials for the speeds examined. For defined speeds, sub-millimeter and sub-degree kinematic accuracy and precision were achieved using an unmodified clinical biplane fluoroscope for quantification of glenohumeral motion.     

Effects of an improved biomechanical backpack strap design on load transfer to the shoulder soft tissues

The aim of the present study was to characterize shoulder strap structure and mechanical properties that may alleviate strains and stresses in the soft tissues of the shoulder. Utilizing a finite element model of the shoulder constructed from a single subject, we have quantified skin stresses exerted by backpack straps and the strains at the subclavian artery (SCA). For this end, standard shape straps with stiffness of 0.5, 1.2, and 5 MPa, were compared to the effects of optimized straps; a double-layered (soft outer layer and reinforced internal supporting layer) and newly-designed anatomically-shaped strap. Compared to the standard 0.5 MPa strap, the 5 MPa strap resulted in 4-times lower SCA strains and 2-times lower Trapezius stresses. The double-layered strap resulted in 40% and 50% reduction in SCA strains and skin stresses, respectively, with respect to the softer strap. The newly-designed anatomical strap exerted 4-times lower SCA strains and 50% lower skin stresses compared to the standard strap. This demonstrates a substantial improvement to the load carriage ergonomics when using a composite anatomical strap.     

Maximality of shoulder external rotation effort in patients presenting with work related injury: The clinical applicability of the DEC parameter

The aim of the present study is to examine the applicability of the isokinetic DEC parameter for identifying submaximal effort in workers with potential weakness of the shoulder external rotators. A previous study indicated that the DEC was a powerful identifier of submaximal effort of shoulder external rotation in normal volunteers. Its applicability in shoulder injury patients is of specific interest. Thus, a retrospective study of 74 (33 female and 41 male) patients who claimed compensation for work-related shoulder injury was designed. 52 patients had their injured side DEC values within the normal range and were thus labeled as maximal performers. Ten patients had higher than cutoff DEC values, indicating submaximal effort whereas 12 patients had exceedingly low DEC values. Gender comparison showed a significantly different proportion of maximal performers. Strength deficits registered in patients demonstrating maximal performance correlated with the final outcome. The findings support the application of the DEC for determination of the extent of weakness of shoulder external rotators in male patients. In terms of shoulder external rotators status in male worker injury, the results support the application of isokinetic tests both in the clinical and medicolegal sense. However, the gender discrepancy warrants further research.