Shoulder muscle forces during driving: Sudden steering can load the rotator cuff beyond its repair limit

Return to driving post upper or lower extremity orthopaedic surgical procedures: a scoping review of current published literature

Patients undergoing planned or unplanned orthopaedic procedures involving their upper or lower extremity can prevent them from safe and timely return to driving, where they commonly ask, 'Doctor, when can I drive?' Driving recommendations after such procedures are varied. The current evidence available is based on a heterogenous data set with varying degrees of sample size and markedly differing study designs. This instructional review article provides a scoping overview of studies looking at return to driving after upper or lower extremity surgery in both trauma and elective settings and, where possible, to provide clinical recommendations for return to driving. Medline, EMBASE, SCOPUS, and Web of Science databases were searched according to a defined search protocol to elicit eligible studies. Articles were included if they reviewed adult drivers who underwent upper or lower extremity orthopaedic procedures, were written in English, and offered recommendations about driving. A total of 68 articles were included in the analysis, with 36 assessing the lower extremity and 37 reviewing the upper extremity. The evidence available from the studies reviewed was of poor methodological quality. There was a lack of adequately powered, high quality, randomised controlled trials (RCTs) with large sample sizes to assess safe return to driving for differing subset of injuries. Many articles provide generic guidelines on return to driving when patients feel safe to perform an emergency stop procedure with adequate steering wheel control. In future, RCTs should be performed to develop definitive return to driving protocols in patients undergoing upper and lower extremity procedures.

Biceps Tenodesis cannot be used as primary treatment option in baseball pitchers with intact rotator cuff muscles

Background Surgeons remain hesitant to perform biceps tenodesis in athletes with type II superior labrum anterior-to-posterior tears due to the lack of reported clinical outcomes for individual overhead throwing sports and associated concerns that this may predispose the joint to instability. This study aimed to assess the effect of biceps tenodesis on shoulder stability for major overhead throwing sports to aid sport-specific surgical decision-making for athletes with type II superior labrum anterior-to-posterior tears.

METHODS

This is a combined modelling and experimental study. Motion data and external forces were measured from 13 participants performing five overhead throwing motions. These data served as input into a musculoskeletal shoulder model that quantifies shoulder stability and muscle loading.

FINDINGS

The loading of the long head of the biceps brachii decreases significantly following biceps tenodesis in three overhead throwing motions (p = 0.02). The loss in joint stability following biceps tenodesis is compensated by a non-significant increase in rotator cuff muscle force which maintains shoulder stability across all overhead throwing motions, except baseball pitching (p = 0.01). The presence of a full-thickness supraspinatus tear post biceps tenodesis further decreases shoulder stability in four of the five overhead throwing motions (p = 0.01).

INTERPRETATION

The study findings demonstrate that an increase in rotator cuff muscle force maintains joint stability for all overhead throwing motions post biceps tenodesis, except baseball pitching. As the presence of a full-thickness tear of the supraspinatus significantly reduces joint stability, biceps tenodesis may be used as a primary treatment in overhead throwing athletes with intact rotator cuff muscles, except baseball pitchers.

LEVEL OF EVIDENCE

Controlled Laboratory Study; Level of Evidence 3.

Meta-analysis of the effects of game types and devices on older adults-video game interaction: Implications for video game training on cognition

Video game training can effectively improve the cognition of older adults. However, whether video game types and game devices influence the training effects of video games remains controversial. This meta-analysis aimed to access and evaluate the effects of video game types and game devices in video game training on the cognition of older adults. Interestingly, results indicated that mouse/keyboard was superior over other video game devices on perceptual-motor function. The effect size (Hedge's g) for perceptual-motor function decreased by 1.777 and 1.722 when the video game training device changed from mouse/keyboard to driving simulator and motion controller. The effects of cognitive training game and conventional video game were moderated by session length. More well-designed studies are required to clarify the unique efficacy of video game types and devices for older adults with video game training.

A biomechanical confirmation of the relationship between critical shoulder angle (CSA) and articular joint loading

BACKGROUND

The critical shoulder angle (CSA) has been shown to be correlated with shoulder disease states. The biomechanical hypothesis to explain this correlation is that the CSA changes the shear and compressive forces on the shoulder. The objective of this study is to test this hypothesis by use of a validated computational shoulder model. Specifically, this study assesses the impact on glenohumeral biomechanics of modifying the CSA.

METHODS

An inverse dynamics 3-dimensional musculoskeletal model of the shoulder was used to quantify muscle forces and glenohumeral joint forces. The CSA was changed by altering the attachment point of the middle deltoid into a normal CSA (33°), a reduced CSA of 28°, and an increased CSA of 38°. Subject-specific kinematics of slow and fast speed abduction in the scapular plane and slow and fast forward flexion measured by a 3-dimensional motion capture system were used to quantify joint reaction shear and compressive forces.

RESULTS

Increasing the CSA results in increased superior-inferior forces (shearing forces; integrated over the range of motion; P < .05). Reducing CSA results in increased lateromedial (compressive) forces for both the maximum and integrated sum of the forces over the whole motion (P < .01).

DISCUSSION/CONCLUSION

Changes in the CSA modify glenohumeral joint biomechanics with increasing CSA producing higher shear forces that could contribute to rotator cuff overuse, whereas reducing the CSA results in higher compressive forces that contribute to joint wear.

[Evaluation of driving fitness in patients with musculoskeletal disorders : A systematic review]

OBJECTIVE

Driving a motor vehicle is one of the most important aspects of personal mobility in our society. However, there is a lack of evidence regarding driving fitness after orthopedic or trauma surgery-related diseases. Aim of this systematic review was to support the treating physician to determine the individual driving fitness in patients with musculosceletal disorders.

MATERIAL AND METHODS

A systematic analysis was performed using the PubMed database. Following a predefined algorithm, all relevant articles published from 2013 to 2018 were included.

RESULTS

The results were categorized according to the affected part of the body into I. lower extremity and II. upper extremity. Also, results were subcategorized into movement restrictions caused by external joint-braces, musculoskeletal diseases, and postoperative conditions.

CONCLUSION

This article supports the treating physician to individually determine the driving fitness in patients with musculoskeletal disorders. However, only a few standardized tests exist to individually determine the driving fitness in patients with musculoskeletal disorders. A particular shortcoming was observed for impairments of the upper extremity.

Is Arthroscopic Transosseous Rotator Cuff Repair Strength Dependent on the Tunnel Angle?

Background

Previous studies have aimed to biomechanically improve the transosseous tunnel technique of rotator cuff repair. However, no previous work has addressed tunnel inclination at the time of surgery as an influence on the strength of the repair construct.

Hypothesis

We hypothesized that the tunnel angle and entry point would influence the biomechanical strength of the transosseous tunnel in rotator cuff repair. Additionally, we investigated how tunnel length and bone quality affect the strength of the repair construct.

Study Design

Controlled laboratory study.

Methods

Mechanical testing was performed on 10 cadaveric humeri. Variations in the bone tunnel angle were imposed in the supraspinatus footprint to create lateral tunnels with inclinations of 30°, 45°, and 90° relative to the longitudinal axis of the humeral shaft. A closed loop of suture was passed through the bone tunnel, and cyclic loading was applied until failure of the construct. Load to failure and distance between entry points were the dependent variables. Analysis of variance, post hoc paired t tests, and the Bonferroni correction were used to analyze the relationship between the tunnel angle and failure load. The Pearson correlation coefficient was then used to evaluate the correlation of the distance between entry points to the ultimate failure load, and t tests were used to compare failure loads between healthy and osteoporotic bone.

Results

Tunnels drilled perpendicularly to the longitudinal axis (90°) achieved the highest mean failure load (167.51 ± 48.35 N). However, there were no significant differences in the failure load among the 3 tested inclinations. Tunnels drilled perpendicularly to the longitudinal axis (90°) measured 13.86 ± 1.35 mm between entry points and were significantly longer (P = .03) than the tunnels drilled at 30° and 45°. We found no correlation of the distance between entry points and the ultimate failure load. Within the scope of this study, we could not identify a significant effect of bone quality on failure load.

Conclusion

The tunnel angle does not influence the strength of the bone-suture interface in the transosseous rotator cuff repair construct.

Clinical Relevance

The transosseous technique has gained popularity in recent years, given its arthroscopic use. These findings suggest that surgeons should not focus on the tunnel angle as they seek to maximize repair strength.

Position of the rotator cuff footprint in relation to the centre of rotation of the humeral head

BACKGROUND

The objective of the present study was to determine the size and position of the rotator cuff moment arms constructed from the cuff footprints, incident on the line of force acting through the humeral head.

METHODS

Five humeri were dissected, leaving the footprints of the rotator cuff intact. Each of the rotator cuff footprints and the cartilage/calcar interface were digitized and the articular surface was scanned using a high precision surface laser scanner. All of the data were merged into the same coordinate system. The centroid of each cuff footprint, centroid of the articular surface of the humerus (G) and the centroid of the articular surface of the glenoid (P) were calculated. Moment arms were measured as the intersection of a perpendicular line of force from each footprint centroid onto the resultant line of force to the centroid of the Glenoid (P).

RESULTS

The mean moment arms of the supraspinatus, infraspinatus and subscapularis muscles were incident close to the centroid (G), whereas teres minor was lateral to the centroid, consistently.

CONCLUSIONS

The teres minor moment arm aligned distal to the centroid of the sphere, consistently. The results may provide an understanding of the function of each muscle as a mobilizer or stabilizer of the glenohumeral joint. Further investigation is necessary.

Improving Musculoskeletal Model Scaling Using an Anatomical Atlas: The Importance of Gender and Anthropometric Similarity to Quantify Joint Reaction Forces

OBJECTIVE

The accuracy of a musculoskeletal model relies heavily on the implementation of the underlying anatomical dataset. Linear scaling of a generic model, despite being time and cost efficient, produces substantial errors as it does not account for gender differences and inter-individual anatomical variations. The hypothesis of this study is that linear scaling to a musculoskeletal model with gender and anthropometric similarity to the individual subject produces similar results to the ones that can be obtained from a subject-specific model.

METHODS

A lower limb musculoskeletal anatomical atlas was developed consisting of ten datasets derived from magnetic resonance imaging of healthy subjects and an additional generic dataset from the literature. Predicted muscle activation and joint reaction force were compared with electromyography and literature data. Regressions based on gender and anthropometry were used to identify the use of atlas.

RESULTS

Primary predictors of differences for the joint reaction force predictions were mass difference for the ankle (p < 0.001) and length difference for the knee and hip (p ≤ 0.017). Gender difference accounted for an additional 3% of the variance (p ≤ 0.039). Joint reaction force differences at the ankle, knee, and hip were reduced by between 50% and 67% (p = 0.005) when using a musculoskeletal model with the same gender and similar anthropometry in comparison with a generic model.

CONCLUSION

Linear scaling with gender and anthropometric similarity can improve joint reaction force predictions in comparison with a scaled generic model.

SIGNIFICANCE

The presented scaling approach and atlas can improve the fidelity and utility of musculoskeletal models for subject-specific applications.

Design and Evaluation of a Surface Electromyography-Controlled Steering Assistance Interface

Millions of drivers could experience shoulder muscle overload when rapidly rotating steering wheels and reduced steering ability at increased steering wheel angles. In order to address these issues for drivers with disability, surface electromyography (sEMG) sensors measuring biceps brachii muscle activity were incorporated into a steering assistance system for remote steering wheel rotation. The path-following accuracy of the sEMG interface with respect to a game steering wheel was evaluated through driving simulator trials. Human participants executed U-turns with differing radii of curvature. For a radius of curvature equal to the minimum vehicle turning radius of 3.6 m, the sEMG interface had significantly greater accuracy than the game steering wheel, with intertrial median lateral errors of 0.5 m and 1.2 m, respectively. For a U-turn with a radius of 7.2 m, the sEMG interface and game steering wheel were comparable in accuracy, with respective intertrial median lateral errors of 1.6 m and 1.4 m. The findings of this study could be utilized to realize accurate sEMG-controlled automobile steering for persons with disability.

Driver drowsiness detection based on classification of surface electromyography features in a driving simulator

Driver drowsiness is a significant cause of fatal crashes every year in the world. In this research, driver's drowsiness is detected by classifying surface electromyography signal features. The tests are conducted on 13 healthy subjects in a driving simulator with a monotonous route. The surface electromyography signal from the upper arm and shoulder muscles are measured including mid deltoid, clavicular portion of the pectoralis major, and triceps and biceps long heads. Signals are separated into 30-s epochs. Five features including range, variance, relative spectral power, kurtosis, and shape factor are extracted. The Observer Rating of Drowsiness evaluates the level of drowsiness. A binormal function is fitted for each feature. For classification, six classifiers are applied. The results show that the k-nearest neighbor classifier predicts drowsiness by 90% accuracy, 82% precision, 77% sensitivity, and 92% specificity.

Risk factors associated with self-reported musculoskeletal pain among short and long distance industrial gas delivery truck drivers

AIM

This study investigated and compared the associations between self-reported exposures to individual as well as work-related physical and psychosocial risk factors for musculoskeletal (MS) disorders and the prevalence of MS symptoms in different body areas among short- (P&D) and long-distance (Bulk delivery) truck drivers working for the same large gas delivery company in Canada.

METHODS

123 truck drivers nationwide participated in this questionnaire-based cross-sectional study. Univariate and multivariate logistic regression analyses were performed.

RESULTS

43.1% of drivers reported MS pain in at least one body area over the past 12 months and 26.8% over the past 7 days. Bulk drivers had a significantly higher prevalence of MS pain than P&D drivers for both periods. When P&D and Bulk drivers were pooled together, belonging to the Bulk subgroup emerged as the strongest factor for low back pain (OR = 8.45, p = 0.002), for shoulder pain (OR = 3.70, p = 0.027) and for MS pain in any body area (OR = 4.05, p = 0.006). In Bulk drivers "High effort-reward imbalance" was strongly associated with MS pain in any body area (OR = 6.47, p = 0.01), with shoulder pain (OR = 4.95, p = 0.016), and with low back pain (OR = 4.51, p = 0.02). In P&D drivers MS pain in any body area was strongly associated with "Working with hands above shoulders" (OR = 6.58, p = 0.009) and "Whole-body vibration" (OR = 5.48, p = 0.018), while shoulder pain was strongly associated with "Hand-arm vibration" (OR = 7.27, p = 0.041).

CONCLUSIONS

Prevalence of MS pain was higher among industrial gas delivery truck drivers than in the general Quebec male worker population, and higher for Bulk drivers compared to P&D drivers. MS pain in Bulk drivers was mainly associated with psychosocial risk factors and lifestyle; MS pain in P&D drivers was mainly associated with physical risk factors.

Analysis of shoulder compressive and shear forces during functional activities of daily life

BACKGROUND

Knowledge of forces acting through the glenohumeral joint during activities of daily living is a prerequisite for improving implant design and aiding rehabilitation planning. Existing data are limited by the number of activities performed and, in some cases, the lack of representation of the glenohumeral loading direction, although high shear force components may cause joint dislocation or implant loosening. This study aims to analyse shoulder compression and shear force components during essential functional activities of daily living.

METHODS

This is a combined modelling and experimental study. Motion data and external forces measured from 25 participants for 26 activities of daily living serve as input into an upper limb musculoskeletal model that quantifies glenohumeral loading.

FINDINGS

The shoulder contact force exceeds 50% of the body weight in 10/26 activities of daily living with a maximum contact force of 164% of the body weight (SD 69%) for a sit to stand task. The ratio of glenohumeral shear force component to compression force component exceeds 0.5 in 8/26 functional activities, with maximum ratios for reaching across the body (1.09; SD 0.41) and pick and place an everyday object (0.88; SD 0.36).

INTERPRETATION

This study demonstrates substantial loads through the glenohumeral joint during activities of daily living. The ratios of glenohumeral shear force component to compression force component are considerable when high loads act at long lever arms and at high angles of arm elevation. These glenohumeral ratios represent a key component of loading that should be considered when designing implants, surgical procedures, or rehabilitation protocols.

Impaired contractile function of the supraspinatus in the acute period following a rotator cuff tear

Background

Rotator cuff (RTC) tears are a common clinical problem resulting in adverse changes to the muscle, but there is limited information comparing histopathology to contractile function. This study assessed supraspinatus force and susceptibility to injury in the rat model of RTC tear, and compared these functional changes to histopathology of the muscle.

Methods

Unilateral RTC tears were induced in male rats via tenotomy of the supraspinatus and infraspinatus. Maximal tetanic force and susceptibility to injury of the supraspinatus muscle were measured in vivo at day 2 and day 15 after tenotomy. Supraspinatus muscles were weighed and harvested for histologic analysis of the neuromuscular junction (NMJ), intramuscular lipid, and collagen.

Results

Tenotomy resulted in eventual atrophy and weakness. Despite no loss in muscle mass at day 2 there was a 30% reduction in contractile force, and a decrease in NMJ continuity and size. Reduced force persisted at day 15, a time point when muscle atrophy was evident but NMJ morphology was restored. At day 15, torn muscles had decreased collagen-packing density and were also more susceptible to contraction-induced injury.

Conclusion

Muscle size and histopathology are not direct indicators of overall RTC contractile health. Changes in NMJ morphology and collagen organization were associated with changes in contractile function and thus may play a role in response to injury. Although our findings are limited to the acute phase after a RTC tear, the most salient finding is that RTC tenotomy results in increased susceptibility to injury of the supraspinatus.

Differences between obese and non-obese drivers in preferred vehicle interior components setting and driving posture

This study compared obese and non-obese drivers in the preferred seat and steering wheel setting and preferred driving posture. Twenty-one extremely obese and 23 non-obese drivers participated. Each participant determined the most preferred setting of the interior components using an adjustable vehicle mock-up; the preferred components setting and corresponding preferred driving posture were recorded. The participant groups exhibited significant differences in the preferred interior components setting. The obese group created larger steering wheel-seat space than the non-obese, with greater rearward seat displacement, more upright steering wheel angle and smaller steering wheel column displacement. It also exhibited more upright seatback angle deemed necessary for facilitating steering wheel reach with the increased steering wheel-seat distance. The between-group differences in the preferred driving posture were less pronounced: no significant group mean angle differences were found except for the elbow joint angles. Also, the mean hip joint centre positions did not significantly differ. Practitioner Summary: To contribute to larger driver packaging, this study compared obese and non-obese drivers in the preferred vehicle interior components setting and driving posture. The obese group created significantly larger space between the steering wheel and seat than the non-obese, through interior components adjustments. The between-group postural differences were less pronounced.

Glenohumeral contact force during flat and topspin tennis forehand drives

The primary role of the shoulder joint in tennis forehand drive is at the expense of the loadings undergone by this joint. Nevertheless, few studies investigated glenohumeral (GH) contact forces during forehand drives. The aim of this study was to investigate GH compressive and shearing forces during the flat and topspin forehand drives in advanced tennis players. 3D kinematics of flat and topspin forehand drives of 11 advanced tennis players were recorded. The Delft Shoulder and Elbow musculoskeletal model was implemented to assess the magnitude and orientation of GH contact forces during the forehand drives. The results showed no differences in magnitude and orientation of GH contact forces between the flat and topspin forehand drives. The estimated maximal GH contact force during the forward swing phase was 3573 ± 1383 N, which was on average 1.25 times greater than during the follow-through phase, and 5.8 times greater than during the backswing phase. Regardless the phase of the forehand drive, GH contact forces pointed towards the anterior-superior part of the glenoid therefore standing for shearing forces. Knowledge of GH contact forces during real sport tasks performed at high velocity may improve the understanding of various sport-specific adaptations and causative factors for shoulder problems.