Long-term follow-up of conservatively treated midshaft clavicular fractures on functional outcome.

BACKGROUND: The aim of this study was to examine the long-term effect of shortening after a midshaft clavicular fracture on strength deficiency in the shoulder. METHOD: This study included 18 participants (14 males, 4 females) with a conservatively treated midshaft clavicular fracture. Mean age was 52.2 ±â€¯13.8 years, range 32-76 years). The mean follow-up time was 13.5 ±â€¯0.4 years. Participants filled in a QUICKDASH questionnaire and both clavicle lengths were measured using a caliper. The isometric strengths in internal rotation, external rotation and abduction of both arms were measured with a handheld dynamometer. RESULTS: Average shortening of the clavicle in this group was 1.09 cm (SD 0.53). Nearly all strength measurements showed no significant difference between the shortened and the unaffected side. Multiple regression revealed a small (3N per mm length difference) but statistically significant relationship on external rotation between the relative extent of shortening of the clavicle, dominant side of the fracture and the isometric force difference between the unaffected and affected arm, F(2,15) = 5.746, p < .05, adj. R2 = .358. Over 14 years there was a reduction in mean DASH-score of 4.4 (8.8 ±â€¯12.3; current DASH = 4.4 ±â€¯7.7)In this group, long term effects of clavicular shortening were small. Based on these results we conclude that on the long term clavicular shortening will not result in significant strength loss.

Surgical fixation of midshaft clavicle fractures: A systematic review of biomechanical studies.

PURPOSE: Surgical treatment of displaced midshaft clavicle fractures requires a decision between plate fixation and intramedullary (IM) fixation. Numerous studies report on the biomechanical properties of various repair constructs. The goal of this systematic review was to provide an overview of studies describing the biomechanical properties of the most commonly used surgical fixations of midshaft clavicle fractures. Additionally, we aimed to translate these biomechanical results into clinically relevant conclusions. METHODS: A computer-aided search of the EMBASE and PudMed/MEDLINE databases was conducted. Studies included for review compared biomechanical properties of plate fixation with IM fixation and superiorly positioned plates with anteroinferiorly positioned plates for midshaft clavicle fractures. RESULTS: Fifteen studies were eligible for inclusion. Plate fixation seemed to form a more robust construct than IM fixation in terms of stiffness and failure loading. The remaining clavicle was stronger after removal of the IM device than after removal of the plate. Superior plating of transverse fractures generally seemed to provide greater stiffness and strength during bending loads than anteroinferior plating did. The absence of cortical alignment in wedge and comminuted fractures directly influenced the fixation stability for both IM fixation and plate fixation, regardless of location. CONCLUSION: Each type of fracture fixation has biomechanical advantages and disadvantages. However, exact thresholds of stiffness for inducing healing and failure strength to withstand refractures are unknown. The clinical relevance of the biomechanical studies may be arguable. Since none of the studies investigate the effect of tissue adaptation over time they should be interpreted with caution.

Wheelchair Mobility Performance Enhancement by Changing Wheelchair Properties: What Is the Effect of Grip, Seat Height, and Mass?

PURPOSE: To provide insight on the effect of wheelchair settings on wheelchair mobility performance (WMP). METHODS: Twenty elite wheelchair basketball athletes of low (n = 10) and high classification (n = 10) were tested in a wheelchair-basketball-directed field test. Athletes performed the test in their own wheelchairs, which were modified for 5 additional conditions regarding seat height (high-low), mass (central-distributed), and grip. The previously developed inertial-sensor-based WMP monitor was used to extract wheelchair kinematics in all conditions. RESULTS: Adding mass showed most effect on WMP, with a reduced average acceleration across all activities. Once distributed, additional mass also reduced maximal rotational speed and rotational acceleration. Elevating seat height had an effect on several performance aspects in sprinting and turning, whereas lowering seat height influenced performance minimally. Increased rim grip did not alter performance. No differences in response were evident between low- and high-classified athletes. CONCLUSIONS: The WMP monitor showed sensitivity to detect performance differences due to the small changes in wheelchair configuration. Distributed additional mass had the most effect on WMP, whereas additional grip had the least effect of conditions tested. Performance effects appear similar for both low- and high-classified athletes. Athletes, coaches, and wheelchair experts are provided with insight into the performance effect of key wheelchair settings, and they are offered a proven sensitive method to apply in sport practice, in their search for the best wheelchair-athlete combination.

The Future of Classification in Wheelchair Sports: Can Data Science and Technological Advancement Offer an Alternative Point of View?

PURPOSE: Classification is a defining factor for competition in wheelchair sports, but it is a delicate and time-consuming process with often questionable validity. New inertial sensor-based measurement methods applied in match play and field tests allow for more precise and objective estimates of the impairment effect on wheelchair-mobility performance. The aim of the present research was to evaluate whether these measures could offer an alternative point of view for classification. METHODS: Six standard wheelchair-mobility performance outcomes of different classification groups were measured in match play (n = 29), as well as best possible performance in a field test (n = 47). RESULTS: In match results, a clear relationship between classification and performance level is shown, with increased performance outcomes in each adjacent higher-classification group. Three outcomes differed significantly between the low- and mid-classified groups, and 1, between the mid- and high-classified groups. In best performance (field test), there was a split between the low- and mid-classified groups (5 out of 6 outcomes differed significantly) but hardly any difference between the mid- and high-classified groups. This observed split was confirmed by cluster analysis, revealing the existence of only 2 performance-based clusters. CONCLUSIONS: The use of inertial sensor technology to obtain objective measures of wheelchair-mobility performance, combined with a standardized field test, produced alternative views for evidence-based classification. The results of this approach provide arguments for a reduced number of classes in wheelchair basketball. Future use of inertial sensors in match play and field testing could enhance evaluation of classification guidelines, as well as individual athlete performance.

Effect of latissimus dorsi flap breast reconstruction on the strength profile of the upper extremity.

OBJECTIVE: Dissection of the latissimus dorsi (LD) flap may have a distinct impact on upper extremity function and strength. To date, insufficient differentiation has been made between loss of muscular strength and shoulder function by dissection of the LD muscle per se and loss of function resulting from all excisional surgery, radiation therapy, and reconstructive procedures at the donor site and the recipient site that may have been combined near the shoulder region. METHODS: This study determines the long-term effect of the LD breast reconstruction on the strength profiles of the upper extremity by measuring the isometric torque strength both in seven synergistic- and two contra-movement directions. The Biodex System 3 Pro (Biodex Medical Systems, New York, NY) was used in 12 patients at a mean of 3.5 years after surgery, and in 20 matched controls. Because loss of LD muscle may not result in significant impairment of activities of daily live (ADL) even in cases where objective measurements are decreased, this study simultaneously assessed the subjective function by use of the standardised Disability of Arm, Shoulder and Hand (DASH) questionnaire. RESULTS: This study observed a significant long-term loss of 8.8 Nm or 19% LD torque strength in synergistic movement directions after transplantation of the LD muscle. This loss correlated significantly with an increase of the mean DASH score among the patients. CONCLUSIONS: Because no significant loss of contra-movement torque strength was observed, it was concluded that the loss of synergistic torque strength appears to result from the loss of LD function per se.

Effects of vision and lumbar posture on trunk neuromuscular control.

The goal of this study was to determine the effects of vision and lumbar posture on trunk neuromuscular control. Torso perturbations were applied with a pushing device while the subjects were restrained at the pelvis in a kneeling-seated position. Torso kinematics and the muscle activity of the lumbar part of the M. Longissimus were recorded for 14 healthy subjects. Four conditions were included: a flexion, extension and neutral lumbar posture with eyes closed and the neutral posture with eyes open. Frequency response functions of the admittance and reflexes showed that there was no significant difference between the eyes open and eyes closed conditions, thereby confirming that vision does not play a role in the stabilization of the trunk during small-amplitude trunk perturbations. In contrast, manipulating posture did lead to significant differences. In particular, the flexed condition led to a lower admittance and lower reflex contribution compared to the neutral condition. Furthermore, the muscle pre-activation (prior to the onset of the perturbation) was significantly lower in the flexed posture compared to neutral. This confirms that flexing the lumbar spine increases the passive tissue stiffness and decreases the contribution of reflex activity to trunk control.

Kinematic and clinical evaluation of shoulder function after primary and revision reverse shoulder prostheses.

HYPOTHESIS: Results of the reverse shoulder prosthesis on pain are generally satisfying; however, active range of motion (ROM) is often not optimal, especially after revision. A kinematic and clinical analysis of the reverse prosthesis was performed to provide more precise information on its glenohumeral motion pattern. We hypothesized that the difference in the primary and revision cases is due to differences in the motion in the glenohumeral joint. MATERIALS AND METHODS: The motion pattern of 31 patients with a reverse prosthesis (35 shoulders, 19 primary and 16 revisions) was measured during 3 active ROM tasks-forward flexion, abduction, and axial rotation. Average age was 71 ± 8 years (range, 58-85 years). Average follow-up was 23 ± 14 months (range, 4-63 months). Kinematic measurements were performed with a 3-dimensional electromagnetic tracking device. Clinical evaluation was performed by obtaining Constant score, Disabilities of Arm, Shoulder and Hand (DASH) score, and the Simple Shoulder Test (SST). Acromial-prosthetic distance was measured on anteroposterior radiographs. RESULTS: Primary placed prostheses showed significantly better active glenohumeral motion than revisions for forward flexion (71° ± 18° vs 53° ± 26°, P < .05), abduction (64° ± 15° vs 46° ± 24°, P < .05), and active external rotation (31° ± 25° vs 13° ± 16°, P < .05). Constant score improved for the whole group from 24 (range, 5-47) to 50 (range, 8-87; P < .001), for the primary group from 28 (range, 13-47) to 60 (range, 8-87; P < .001) and for revisions from 20 (range, 5-47) to 38 (range, 11-73; P < .001). Acromial-prosthetic distance showed no significant correlation for active glenohumeral motion. Five shoulders with a deficient teres minor muscle showed no significant decrease of external rotation. CONCLUSION: Active ROM is better in primary placed prosthesis, and this difference takes place mainly in the glenohumeral joint. In all our patients, Constant scores improved significantly postoperatively. However, we could not find any clinical correlating parameters to explain this difference.

Increased muscle activity to stabilise mobile bearing knees in patients with rheumatoid arthritis.

The aim of this study was to assess the differences in muscle activity (surface EMG) between a posterior stabilised (PS) total knee design and a mobile bearing (MB) posterior cruciate ligament retaining design in rheumatoid arthritis (RA) patients during a step-up task. Four patients with a PS total knee prosthesis and three patients with a MB total knee prosthesis were selected based on pain score, knee function, range of motion and joint stability. Clinical scores and functional scores were comparable between the two groups pre-operatively and at the 1-year follow-up. Visual analysis of the EMG activity of the main flexor and extensor muscles showed that the activity of both extensor and flexor muscles of the MB group was on average higher compared to the PS group. When the maximum activities of the muscles were compared, the patients in the MB group showed a significant higher maximum peak activity (p<0.05) of the Vastus Medialis (VM), Vastus Lateralis (VL) and Semitendinosus (ST) during step-up than the patients in the PS group. Also the instance of activation of the Vastus Medialis and the Vastus Lateralis was significant earlier in the MB group compared to the PS group. Since the differences between the PS and the MB group did not only show an increase of muscle activity but also an earlier activation of the flexor muscles, this may express compensation by coordination. Rehabilitation programs for RA patients should include besides muscle strength training, elements of muscle-coordination training.

Mechanical loading of the low back and shoulders during pushing and pulling activities.

The objective of this study was to quantify the mechanical load on the low back and shoulders during pushing and pulling in combination with three task constraints: the use of one or two hands, three cart weights, and two handle heights. The second objective was to explore the relation between the initial and sustained exerted forces and the mechanical load on the low back and shoulders. Detailed biomechanical models of the low back and shoulder joint were used to estimate mechanical loading. Using generalized estimating equations (GEE) the effects were quantified for exerted push/pull forces, net moments at the low back and shoulders, compressive and shear forces at the low back, and compressive forces at the glenohumeral joint. The results of this study appeared to be useful to estimate ergonomics consequences of interventions in the working constraints during pushing and pulling. Cart weight as well as handle height had a considerable effect on the mechanical load and it is recommended to maintain low cart weights and to push or pull at shoulder height. Initial and sustained exerted forces were not highly correlated with the mechanical load at the low back and shoulders within the studied range of the exerted forces.

Effect of a redesigned two-wheeled container for refuse collecting on mechanical loading of low back and shoulders.

The objective of this study was to compare the mechanical and perceived workload when working with a redesigned two-wheeled container and working with a standard two-wheeled container for refuse collecting. The three changes in the design of the container were a displacement of the position of the centre of mass in the direction of the axis of the wheels, a slight increase in the height of the handle and a slight increase in the horizontal distance between the handle and the wheel-axis, and an increase in the diameter of the wheels. The volume of the container remained 0.240 m3. Nine refuse collectors performed some of their most frequent daily activities with both types of containers in the laboratory. Kinematics and exerted hand forces were assessed as input for detailed 3D biomechanical models of the low back and shoulder to estimate net moments at the low back and shoulders, compressive forces at the low back and contact forces at the glenohumeral joint. Also, the refuse collectors rated the ease of handling the two-wheeled containers on a five point scale. The use of the redesigned container resulted in a decrease of the exerted hand forces of 27%, decreases in the net moments at the low back and shoulders of 8% and 20%, respectively, and a decrease of 32% of the contact force at the glenohumeral joint when compared to the standard container. However, pulling an empty redesigned container on to the pavement resulted in an increase of the shoulder moment of more than 100%. No differences between container types were found for the compressive forces at the low back. Pushing and pulling with the redesigned container was rated as easier than pushing and pulling with the standard container. No differences in subjective ratings were found for the tasks of turning the container or pulling an empty container onto the pavement. It is concluded that, provided that empty containers are placed back onto the pavement as infrequently as possible, the introduction of the redesigned container could result in a reduction of the low back and shoulder load for refuse collectors.

Normative values and determinants of physical capacity in individuals with spinal cord injury.

We reanalyzed data from five studies with similar or identical methodology performed by our laboratory to define normative values and determinants of physical capacity in individuals with tetraplegia and paraplegia. Each study consisted of a graded wheelchair exercise test to determine peak oxygen uptake and maximal power output and could additionally include a wheelchair sprint test to determine short-term (anaerobic) power output and/or an isometric strength test. The combined subject population included 166 individuals (20 women), varying considerably for age, body mass, lesion level, time since injury, and activity level. Ranges in physical capacity parameters were extensive and normative values for individuals with tetraplegia and paraplegia were established. These physical capacity norms could be used for evaluation of fitness status and training or therapeutic interventions. Multiple regression procedures indicated that 48-80% of the variance in physical capacity could be explained by lesion level and completeness, activity level, gender, age, body mass, and time since injury. Although physical capacity is largely determined by factors that cannot be altered, such as lesion level, age, and gender, changeable factors such as activity level and body mass play an additional role.