The effect of the anatomy of the distal humerus and proximal ulna on the positioning of the components in total elbow arthroplasty.

Determining and accurately restoring the flexion-extension axis of the elbow is essential for functional recovery after total elbow arthroplasty (TEA). We evaluated the effect of morphological features of the elbow on variations of alignment of the components at TEA. Morphological and positioning variables were compared by systematic CT scans of 22 elbows in 21 patients after TEA. There were five men and 16 women, and the mean age was 63 years (38 to 80). The mean follow-up was 22 months (11 to 44). The anterior offset and version of the humeral components were significantly affected by the anterior angulation of the humerus (p = 0.052 and p = 0.004, respectively). The anterior offset and version of the ulnar components were strongly significantly affected by the anterior angulation of the ulna (p < 0.001 and p < 0.001). The closer the anterior angulation of the ulna was to the joint, the lower the ulnar anterior offset (p = 0.030) and version of the ulnar component (p = 0.010). The distance from the joint to the varus angulation also affected the lateral offset of the ulnar component (p = 0.046). Anatomical variations at the distal humerus and proximal ulna affect the alignment of the components at TEA. This is explained by abutment of the stems of the components and is particularly severe when there are substantial deformities or the deformities are close to the joint.

Total elbow arthroplasty: Influence of implant positioning on functional outcomes.

BACKGROUND: Restoring the axis of rotation is often considered crucial to achieving good functional outcomes of total elbow arthroplasty. The objective of this work was to evaluate whether variations in implant positioning correlated with clinical outcomes. HYPOTHESIS: Clinical outcomes are dictated by the quality of implant positioning. MATERIAL AND METHODS: A retrospective review was conducted of data from 25 patients (26 elbows). Function was assessed using a pain score, the Disabilities of the Arm, Shoulder, and Hand (DASH) Score, and the Mayo Elbow Performance Score (MEPS). The patients also underwent a clinical evaluation for measurements of motion range and flexion/extension strength. Position of the humeral and ulnar implants was assessed by computed tomography with reconstruction using OsiriX software. Indices reflecting anterior offset, lateral offset, valgus, height, and rotation were computed by subtracting the ulnar value of each of these variables from the corresponding humeral value. These indices provided a quantitative assessment of whether position errors for the two components had additive effects or, on the contrary, counterbalanced each other. Elbows with prosthetic loosening or extensive epiphyseal destruction were excluded. RESULTS: Of the 26 elbows, 5 were excluded. In the remaining 21 elbows, the discrepancy between the humeral and ulnar lateral offsets was significantly associated with pain intensity (P ≤ 0.05) and the MEPS (P ≤ 0.05). Anterior position of the ulna relative to the humerus was associated with decreased extension strength (P ≤ 0.05) and worse results for all functional parameters (P ≤ 0.05). DISCUSSION: In the absence of loosening, positioning errors seem to adversely affect functional outcomes, probably by placing inappropriate stress on the soft tissues. LEVEL OF EVIDENCE: III.

The impact of a register on the management of neonatal cooling in Switzerland.

BACKGROUND: Therapeutic hypothermia following hypoxic ischaemic encephalopathy in term infants was introduced into Switzerland in 2005. Initial documentation of perinatal and resuscitation details was poor and neuromonitoring insufficient. In 2011, a National Asphyxia and Cooling Register was introduced. AIMS: To compare management of cooled infants before and after introduction of the register concerning documentation, neuromonitoring, cooling methods and evaluation of temperature variability between cooling methods. STUDY DESIGN: Data of cooled infants before the register was in place (first time period: 2005-2010) and afterwards (second time period: 2011-2012) was collected with a case report form. RESULTS: 150 infants were cooled during the first time period and 97 during the second time period. Most infants were cooled passively or passively with gel packs during both time periods (82% in 2005-2010 vs 70% in 2011-2012), however more infants were cooled actively during the second time period (18% versus 30%). Overall there was a significant reduction in temperature variability (p < 0.001) comparing the two time periods. A significantly higher proportion of temperature measurements within target temperature range (72% versus 77%, p < 0.001), fewer temperature measurements above (24% versus 7%, p < 0.001) and more temperatures below target range (4% versus 16%, p < 0.001) were recorded during the second time period. Neuromonitoring improved after introduction of the cooling register. CONCLUSION: Management of infants with HIE improved since introducing the register. Temperature variability was reduced, more temperature measurements in the target range and fewer temperature measurements above target range were observed. Neuromonitoring has improved, however imaging should be performed more often.

Changes in running mechanics and spring-mass behaviour during a 5-km time trial.

Research into the biomechanical manifestation of fatigue during exhaustive runs is increasingly popular but additional understanding of the adaptation of the spring-mass behaviour during the course of strenuous, self-paced exercises continues to be a challenge in order to develop optimized training and injury prevention programs. This study investigated continuous changes in running mechanics and spring-mass behaviour during a 5-km run. 12 competitive triathletes performed a 5-km running time trial (mean performance: Ì´17 min 30 s) on a 200 m indoor track. Vertical and anterior-posterior ground reaction forces were measured every 200 m by a 5-m long force platform system, and used to determine spring-mass model characteristics. After a fast start, running velocity progressively decreased (- 11.6%; P<0.001) in the middle part of the race before an end spurt in the final 400-600 m. Stride length (- 7.4%; P<0.001) and frequency (- 4.1%; P=0.001) decreased over the 25 laps, while contact time (+ 8.9%; P<0.001) and total stride duration (+ 4.1%; P<0.001) progressively lengthened. Peak vertical forces (- 2.0%; P<0.01) and leg compression (- 4.3%; P<0.05), but not centre of mass vertical displacement (+ 3.2%; P>0.05), decreased with time. As a result, vertical stiffness decreased (- 6.0%; P<0.001) during the run, whereas leg stiffness changes were not significant (+ 1.3%; P>0.05). Spring-mass behaviour progressively changes during a 5-km time trial towards deteriorated vertical stiffness, which alters impact and force production characteristics.

Alteration in neuromuscular function after a 5 km running time trial.

The aim of this study was to characterize the effect of a 5 km running time trial on the neuromuscular properties of the plantar flexors. Eleven well-trained triathletes performed a series of neuromuscular tests before and immediately after the run on a 200 m indoor track. Muscle activation (twitch interpolation) and normalized EMG activity were assessed during maximal voluntary contraction (MVC) of plantar flexors. Maximal soleus H-reflexes and M-waves were evoked at rest (i.e. H (MAX) and M (MAX), respectively) and during MVC (i.e. H (SUP) and M (SUP), respectively). MVC significantly declined (-27%; P < 0.001) after the run, due to decrease in muscle activation (-8%; P < 0.05) and M (MAX)-normalized EMG activity (-13%; P < 0.05). Significant reductions in M-wave amplitudes (M (MAX): -13% and M (SUP): -16%; P < 0.05) as well as H (MAX)/M (MAX) (-37%; P < 0.01) and H (SUP)/M (SUP) (-25%; P < 0.05) ratios occurred with fatigue. Following exercise, the single twitch was characterized by lower peak torque (-16%; P < 0.001) as well as shorter contraction (-19%; P < 0.001) and half-relaxation (-24%; P < 0.001) times. In conclusion, the reduction in plantar flexors strength induced by a 5 km running time trial is caused by peripheral adjustments, which are attributable to a failure of the neuromuscular transmission and excitation-contraction coupling. Fatigue also decreased the magnitude of efferent motor outflow from spinal motor neurons to the plantar flexors and part of this suboptimal neural drive is the result of an inhibition of soleus motoneuron pool reflex excitability.

Spinal modulations accompany peripheral fatigue during prolonged tennis playing.

To examine the time course of alteration in neural process (spinal loop properties) during prolonged tennis playing, 12 competitive players performed a series of neuromuscular tests every 30 min during a 3-h match protocol. Muscle activation (twitch interpolation) and normalized EMG activity were assessed during maximal voluntary contraction (MVC) of plantar flexors. Spinal reflexes and M-waves were evoked at rest (i.e., H(max) and M(max) , respectively) and during MVC (i.e., H(sup) , V-wave, M(sup) , respectively). MVC torque declined significantly (P<0.001) across the match protocol, due to decrease (P<0.001) in muscle activation and in normalized EMG activity. The impairment in MVC was significantly correlated (r=0.77; P<0.05) with the decline in muscle activation. H(max) /M(max) (P<0.001), H(sup) /M(sup) (P<0.01) and V/M(sup) (P<0.05) ratios were depressed with fatigue and decreased by ∼80%, 46% and 61% at the end of exercise, respectively. Simultaneously, peak twitch torque and M-wave amplitude were significantly (P<0.01) altered with exercise, suggesting peripheral alterations. During prolonged tennis playing, the compromised voluntary strength capacity is linked to a reduced neural input to the working muscles. This central activation deficit partly results from a modulation in spinal loop properties.

Effects of the playing surface on plantar pressures during the first serve in tennis.

PURPOSE: This study aimed at examining the influence of different playing surfaces on in-shoe loading patterns in each foot (back and front) separately during the first serve in tennis. METHODS: Ten competitive tennis players completed randomly five first (ie, flat) serves on two different playing surfaces: clay vs GreenSet. Maximum and mean force, peak and mean pressure, mean area, contact area and relative load were recorded by Pedar insoles divided into 9 areas for analysis. RESULTS: Mean pressure was significantly lower (123 ± 30 vs 98 ± 26 kPa; -18.5%; P < .05) on clay than on GreenSet when examining the entire back foot. GreenSet induced higher mean pressures under the medial forefoot, lateral forefoot and hallux of the back foot (+9.9%, +3.5% and +15.9%, respectively; both P < .01) in conjunction with a trend toward higher maximal forces in the back hallux (+15.1%, P = .08). Peak pressures recorded under the central and lateral forefoot (+21.8% and +25.1%; P < .05) of the front foot but also the mean area values measured on the back medial and lateral midfoot were higher (P < .05) on clay. No significant interaction between foot region and playing surface on relative load was found. CONCLUSIONS: It is suggested that in-shoe loading parameters characterizing the first serve in tennis are adjusted according to the ground type surface. A lesser asymmetry in peak (P < .01) and mean (P < .001) pressures between the two feet was found on clay, suggesting a greater need for stability on this surface.

Effects of active vs. passive recovery on repeated rugby-specific exercises.

The aim of this study was to determine the effects of active vs. passive recovery on performance of a rugby-specific intermittent test in rugby union players. Seven male rugby players (20.6+/-0.5 yrs; 181.9+/-10.0 cm; 94.5+/-12.8 kg) performed in random order, over two separate sessions, a specific repeated-sprint rugby test, the Narbonne test (6 x 4 consecutive actions: 1, scrummaging; 2, agility sprinting; 3, tackling; 4, straight sprinting) with 30s of passive or active recovery (running at 50% of maximal aerobic speed). The Narbonne tests were completed before (pre-test) and after (post-test) a 30-min rugby match. During the Narbonne test, scrum forces, agility and sprint times, heart rate and rate of perceived exertion were measured. Scrum forces were lower in active (74.9+/-13.4 kg) than in passive recovery (90.4+/-20.9 kg), only during the post-test (p<0.05). Fatigue index (%) (p<0.05) and total sprint time (s) (p<0.01) were significantly greater in active than in passive recovery, both during the pre-test (11.5+/-5.7% vs. 6.7+/-4.5% and 18.1+/-1.3s vs. 16.9+/-0.9s) and the post-test (7.3+/-3.3% vs. 4.3+/-1.5% and 18.3+/-1.6s vs. 16.9+/-1.1s). Consequently, the results indicated that passive recovery enabled better performance during the Narbonne test. However, it is obviously impractical to suggest that players should stand still during and following repeated-sprint bouts: the players have to move to ensure they have taken an optimal position.

Effects of the playing surface on plantar pressures and potential injuries in tennis.

OBJECTIVES: To examine the influence of different playing surfaces on in-shoe loading patterns during tennis-specific movements. METHODS: Ten experienced male players performed two types of tennis-specific displacements (serve and volley (SV) and baseline play (BA)) on two different playing surfaces; eg, clay vs Greenset. Maximum and mean force and pressure, contact time, contact area and relative load were recorded by an insole with 99 sensors (X-Pedar system) divided into 9 areas. RESULTS: Regarding the whole foot, mean (SD) force (SV: 615 (91) vs 724 (151) N; -12.4%, p<0.05 and BA: 614 (73) vs 717 (133) N; -11.6%, p<0.05) was lower on clay than on Greenset, whereas contact time was longer (SV: 299 (113) vs 270 (148) ms; +16.5%, NS and BA: 354 (72) vs 272 (60) ms; +30.3%, p<0.001). Greenset induced higher loading in the hallux (SV: +15.3%, p<0.05 and BA: +11.4%, not significant) and lesser toes areas (SV: +12.6%, p<0.05 and BA: +18.0%, p<0.01). In contrast, the relative load on the medial (SV: +27.4%, p<0.05 and BA: +16.1%, p = 0.06) and lateral midfoot (SV: +23.3%, p<0.05 and BA: +28.3%, p<0.01) was higher on clay. CONCLUSIONS: This study demonstrates that playing surface affects plantar loading in tennis: Greenset induced higher loading in the hallux (SV: +15.3%, p<0.05 and BA: +11.4%, NS) and lesser toes areas (SV: +12.6%, p<0.05 and BA: +18.0%, p<0.01) but lower relative load on the medial (SV: -27.4%, p<0.05 and BA: -16.1%, p = 0.06) and lateral midfoot (SV: -23.3%, p<0.05 and BA: -28.3%, p<0.01) than clay.

The performance and efficiency of cycling with a carbon fiber eccentric chainring during incremental exercise.

AIM: The aim of this study was to compare cycling performance and efficiency of a carbon fiber eccentric chainring (EC) versus a metallic standard chainring (SC) during an incremental exercise. The main feature of EC was that crank-arm length changed as a function of the crank angle, being maximal during the pushing phase and minimal during the recovery one. Because of its design, cycling with EC was expected to develop higher torque during the downstroke, and lower torque during the upstroke, thus increasing mechanical efficiency and requiring lower cardioventilatory solicitation at submaximal exercise intensities. METHODS: Eleven male subjects performed two incremental cycle tests in a randomized order using EC and SC successively. Cardioventilatory data were recorded every minute using an automated breath-by-breath system. Blood samples were taken at rest, exhaustion, 5 and 15 minutes of recovery to access lactate concentrations, [LA], mmol . L(-1) . RESULTS: The subjects reached significantly lower maximal speed at volitional exhaustion with EC compared with SC (39.4+/-2.5 versus 41.5+/-2.9 km . h(-1), respectively; P<0.05). Analysis of variance revealed significantly higher values for oxygen uptake and carbon dioxide production during incremental exercise with EC (P<0.05). Lastly, [LA] at exhaustion were similar with the two chainrings. CONCLUSIONS: The carbon fiber EC tested in this study failed to enhance cycling performance and efficiency throughout an incremental exercise. This indicated that carbon fibers did not exhibited its expected mechanical advantage.

Failed excitability of spinal motoneurons induced by prolonged running exercise.

The main purpose of this study was to investigate the modulations in H-reflex and V-wave responses (spinal loop properties) induced by prolonged locomotion activities. The second purpose was to compare the development of central fatigue between continuous and intermittent running modes. Eleven males randomly performed two 90-min running exercises either continuously (CONT, first ventilatory threshold) or intermittently (INT, 150 s at a velocity 20% higher than that during CONT/30 s of recovery). Neuromuscular tests of the plantar flexors [including M-wave and H-reflex at rest and M-wave and V-wave during maximal voluntary contraction (MVC)] were performed before and 5 and 30 min after the running exercises. During MVC, the torque significantly decreased (P < 0.05) from preexercise to 5 and 30 min postexercise (-11 and -9%, respectively), as did the RMS/M ratio (-11 and -13%, respectively) and the V/M ratio (-19 and -37%, respectively) for the soleus muscle. At rest, the H/M ratio also decreased significantly (P < 0.001) from preexercise to 5 and 30 min postexercise (-61 and -55%, respectively). Last, no difference in the alteration of spinal loop properties was noted between CONT and INT. In conclusion, the results regarding H-reflex and V-wave suggest for the first time a modulation in spinal loop properties after prolonged running.

Specific incremental field test for aerobic fitness in tennis.

OBJECTIVES: To compare metabolic and cardiorespiratory responses between subjects undergoing incremental treadmill (non-specific) and tennis field based (sport specific) tests. METHODS: Nine junior competitive tennis players randomly performed two incremental protocols to exhaustion: a treadmill test (TT) and a tennis specific fitness test (FT). The FT consisted of repeated displacements replicating the game of tennis at increasing speed on a court. In both tests, ventilatory variables and heart rate (HR) were determined at the ventilatory threshold (VT), respiratory compensation point (RCP), and maximal loads (max). Blood lactate concentration was determined at the point of volitional fatigue. RESULTS: Percentage (mean (SD)) maximal HR (83.6 (5.1) v 83.0 (2.8) and 92.1 (2.1) v 92.3 (2.1)%, respectively) and percentage maximal oxygen uptake (VO2max) (69.4 (8.1) v 73.5 (6.1) and 84.4 (6.5) v 85.5 (8.7)%, respectively) at the VT and RCP were not different between the FT and TT subjects, whereas VO2max was higher in the FT than in the TT (63.8 (3.0) v 58.9 (5.3) ml/min/kg; p<0.05). Blood lactate concentration (10.7 (3.0) v 10.6 (4.3) mmol/l) did not differ between the TT and FT. CONCLUSIONS: Although cardiorespiratory variables were not different at submaximal intensities between the two tests, VO2max values derived from laboratory measurements were underestimated. Using field testing in addition to treadmill testing provides a better measurement of a player's individual fitness level and may be routinely used to accurately prescribe appropriate aerobic exercise training.

Changes in exercise characteristics, maximal voluntary contraction, and explosive strength during prolonged tennis playing.

OBJECTIVES: To examine changes in exercise characteristics, maximal voluntary contraction, and explosive strength during prolonged tennis playing. METHODS: Maximal isometric voluntary contraction (MVC), leg stiffness (hopping), and peak power in squat (SJ) and countermovement (CMJ) jumps were measured before, every 30 minutes during, and 30 minutes after a three hour tennis match in 12 well trained players. Heart rate (HR), the effective playing time (EPT), rating of perceived exertion (RPE), and muscle soreness of knee extensors were also measured. RESULTS: Decreases in MVC (-9%; p < 0.05) and leg stiffness (-9%; p = 0.17) were observed after the match and were significantly correlated (r = 0.66; p = 0.05). Peak power in SJ and CMJ tests was maintained during the match but was lower (p < 0.001) 30 minutes after. Average HR and EPT were 144 (8) beats/min and 21 (4)% respectively. A strong correlation was found between EPT and HR (r = 0.93; p < 0.05). RPE and muscle soreness increased linearly during the exercise and were significantly correlated (r = 0.99; p < 0.001). CONCLUSIONS: Progressive reductions in maximal voluntary strength and leg stiffness highly correlated with increases in perceived exertion and muscle soreness were observed throughout a three hour tennis match, whereas explosive strength was maintained and decreased only after the match. These alterations may result in less efficient on-court movement and stroke production. They are, however, lower than those reported during continuous exercise of the same duration. The intermittent pattern of tennis and the numerous stretch-shortening cycle movements partly explain these results.

The intensity level of physical exercise and the bone metabolism response.

This study investigated the short-term effects of the intensity level of physical exercise on bone metabolism and related hormones. The responses of calciotropic hormones and bone biochemical markers were evaluated in seven male cyclists (mean age 24.4 years, range 20-39) during two 50-min cycling tests performed 15% below (-VT) and 15% above (+VT) the ventilatory threshold. In each test, venous blood samples were drawn at rest, at the 30th and 50th min of exercise, and after 15 min of recovery. For both intensity levels, no significant variation in calcium, 25-hydroxyvitamin D, 1.25-dihydroxyvitamin D, or cortisol level was observed. Intact parathyroid hormone (iPTH) level increased significantly after the last minute of the test (41%, p < 0.05) and peaked during the recovery (80%, p < 0.05) only in response to exercise performed at +VT. Serum phosphorus concentration rose during both tests, while albumin levels increased only at +VT. Concerning bone cell activity, osteocalcin, and type I-C telopeptide breakdown products transiently increased only in response to exercise performed at +VT (11% and 16.8%, respectively; p < 0.05). Bone alkaline phosphatase increased similarly for both intensity levels after 30 min (12%, p < 0.05) and 50 min (12% for -VT vs. 14% for +VT, p < 0.05). All markers of bone turnover returned to initial values during the recovery. In conclusion, a no-impact but intense and sustained exercise performed at +VT transiently stimulated bone turnover and iPTH secretion, suggesting the existence of a bone stimulation threshold. In addition to the well known effect of mechanical constraints, both the duration and intensity of exercise may induce changes in bone turnover.

Bone loss in spinal cord-injured patients: from physiopathology to therapy.

STUDY DESIGN: Review article on bone metabolism and therapeutic approach on bone loss in patients with spinal cord injury (SCI). OBJECTIVE: The first part aims to describe the process of bone demineralization and its effects on bone mass in patients with SCI. The second part describes and discusses the therapeutic approaches to limiting the alteration in bone metabolism related to neurological lesions. SETTING: Propara Rehabilitation Center, Montpellier, France. RESULTS: During the first 24 months postinjury, demineralization occurs exclusively in the sublesional areas and predominantly in weight-bearing skeletal sites such as the distal femur and proximal tibia, both of which are trabecular-rich sites. Reduced bone mass, in association with a modified bone matrix property and composition, is very likely at the origin of pathological fractures after minor trauma to which these patients are frequently exposed. Since these fractures may be asymptomatic yet may lead to complications, preventing and managing 'neurological osteoporosis' remains a considerable challenge. Two main approaches are considered: the first consists in applying a mechanical stimulus to the bone tissue by standing, orthotically aided walking or functional electrical stimulation (FES). The second uses medications, particularly antiresorptive drugs such as calcitonin or diphosphonates. CONCLUSION: To develop well-adapted treatments, a more precise understanding of bone loss etiology is needed. The current rehabilitation programs are based on the idea that the bone physiological changes observed in patients with SCI are due to immobility, but results indicate that alterations inherent to neurological damage may play an even greater role in inducing osteoporosis.

Changes in osteoprotegerin/RANKL system, bone mineral density, and bone biochemicals markers in patients with recent spinal cord injury.

This study analyzed the temporal and regional variations in bone loss and explored bone cell activities via biochemical markers during an extended follow-up in patients with spinal cord injury (SCI). In parallel, the possible role of the osteoprotegerin (OPG)/RANKL system in disuse osteoporosis was investigated. Seven male patients with acute and complete SCI (31.3 +/- 9.5 years) and 12 able-bodied (AB) men (26.9 +/- 4.2 years) participated in the study. Measurements were performed 16, 24, 36, 48, and 71 weeks after injury. At week 16, marked calcium homeostasis disturbance and a concomitant increase in bone resorption markers were observed, reflecting an intense bone degradation process. Resorption activity decreased continuously with time. Contrasting with the great rise in the resorption markers, the bone formation markers showed little variation. During the period of investigation, a loss in bone mineral density (BMD) was demonstrated for the total body (-4.3%), pelvis (-15.7%) and lower limbs (-15.2%), whereas BMD did not change at the lumbar spine, upper limbs, or skull. At all stages, SCI patients had lower serum RANKL levels and higher serum OPG levels than did AB controls, but no significant variation with time was observed for either cytokine. These findings suggest that bone resorption persisted long after SCI and specifically affected BMD at sublesional sites. The marked modification of serum OPG/RANKL levels in SCI patients suggests that this system is affected, in disuse osteoporosis. However, the precise biologic role of the OPG/RANKL system in the bone tissue of SCI patients has yet to be determined.

Effects of physical activities that induce moderate external loading on bone metabolism in male athletes.

Sports characterized by little or moderate weight bearing or impact have a low osteogenic effect. However, the action of such sports on bone turnover remains unclear. The objective of this study was to determine the effect on bone remodelling of physical activities that induce moderate external loading on the skeleton. Thirty-eight male athletes aged 18-39 years (cyclists, n = 11; swimmers, n = 13; triathletes, n = 14) and 10 age-matched sedentary controls aged 22-35 years participated in the study. The study combined measurement of bone mineral density by dual-energy X-ray absorptiometry and bone turnover assessment from specific biochemical markers: serum bone-specific alkaline phosphatase, osteocalcin, urinary type I collagen C-telopeptide and calcium. Compared with the controls and swimmers, adjusted bone mineral density was higher (P < 0.05) in triathletes at the total proximal femur and lower limbs. No differences in bone mineral density were found between cyclists, swimmers and controls. Compared with controls, osteocalcin was higher (P < 0.05) in triathletes and swimmers and urinary type I collagen C-telopeptide was higher in swimmers only. Serum bone-specific alkaline phosphatase was lower (P < 0.05) in cyclists than in all other groups. In conclusion, an osteogenic effect was found only in triathletes, mainly at bone sites under high mechanical stress. Bone turnover differed in athletes compared with controls, suggesting that bone turnover may be sport-practice dependent. Despite some encouraging observations, it was not possible to show that changes in the bone remodelling process were sport-discipline dependent.

[Validation of the motor capacities scale: a specific evaluation of manual abilities in tetraplegics who undergo functional surgery of the upper limbs]. / Validation d'une grille de capacités motrices du tétraplégique opéré du ou des membres supérieurs.

OBJECTIVE: Metrological investigation to develop a motor capacities scale (MCS) specifically designed for tetraplegics who undergo a functional surgery of upper limbs. METHODS: From diverse sources-review of literature, discussion with patients and therapists-, 328 daily life activities were compiled. Eighty of them were identified as motor capacities and correspond to basic and functional tasks performed by tetraplegics independently of contextual and environmental factors. Because of the absence of a reference test, a process of validation was required. In the preliminary study, patients and occupational therapists were asked to criticize the pertinence of the study. In the pilot study, patients were assessed on the basis of a protocol. Feasibility of the evaluation was also studied. The intermediate study was focused on the interrater reproducibility. The prefinal study aimed at assessing construct validity. In the final study, the external structure of the scale and responsiveness to change provided by functional surgery were analyzed. RESULTS: The preliminary and pilot studies revealed the good acceptability of the scale by both the patients and the therapists. Face and content validity were enhanced by the multidisciplinary and multicenter approach. Global reproducibility was found to be excellent (intraclass correlation coefficient = 0.99). MCS was correlated with the Sollerman test, the functional independence measure (FIM), the ASIA motor score, dynamometric scores of Jamar and Preston. No correlation was found with the interval since the onset of the tetraplegia, the educational level and the age at the time of the evaluation. A factorial analysis was performed in 125 patients (146 observations) and revealed one main dimension that appears to reflect manual abilities. Responsiveness to change was important regarding the short time following surgery. The final version of the MCS comprises 31 items classified in six functional categories: transfers, positioning on a Bobath's couch, positioning in a wheelchair, locomotion, motor capacities of spatial exploration and motor capacities for grasping and gripping. CONCLUSION: The MCS displays satisfactory metrological properties: a good apparent and content validity, an excellent reproducibility and a good construct validity. The data showed that sensitivity to change was good enough to consider the MCS as a valid means of assessment of the effectiveness of upper limb functional surgery in tetraplegics.

Competitive season of triathlon does not alter bone metabolism and bone mineral status in male triathletes.

This longitudinal study evaluated the effects of a triathlon season on bone metabolism and hormonal status. Seven male competitive triathletes (mean age 19.3 years, range 18 - 20) with 5.0 +/- 0.3 years of competition experience were tested twice during the season: at the beginning of training and 32 weeks later. Total and regional bone mineral density (BMD) was determined by dual-energy X-ray absorptiometry, while bone turnover was evaluated by specific biochemical markers: bone-specific alkaline phosphatase (B-ALP), osteocalcin, and urinary type I collagen C-telopeptide. In addition, sexual, calciotropic and somatotropic hormones were also analyzed. After 32 weeks, a BMD increase was found at the lumbar spine (1.9 %; p = 0.031) and skull (3.1 %; p = 0.048), while no variation was observed for total body or at the proximal femur. The B-ALP level decreased (-23.2 %; p = 0.031), but no variation was found for the other bone markers. 1.25 (OH) (2)D3, IGF-1 and the bioavailability IGF-1 index (IGF-1/IGFBP-3) increased by 18.3 % (p = 0.047), 29 % (p = 0.048), 33 % (p = 0.011), respectively, while PTH, testosterone, IGFBP-3 and cortisol concentrations were unchanged. In conclusion, the triathlon season had a moderately favourable effect on BMD, although a slowing down of bone formation activity was observed. No variation in hormonal levels was observed that could have limited the effects of exercise on bone tissue.

Analysis of mechanical preparations in extracted teeth using ProTaper rotary instruments: value of the safety quotient.

The purpose of this study was to apply the Endographe to analyze the vertical forces and torque developed during mechanical preparations in extracted teeth. The data collected in this study may be used to calculate the safety quotient (SQ) as proposed by J.T. McSpadden. The SQ formula is defined as the torque required to break a file at D3 divided by the mean working torque required to cut dentin. The Endographe is a unique force-analyzer device equipped to measure, record, and generate graphs of the vertical forces and torque exerted during root canal preparation. All preparations were performed by endodontists in roots with narrow, more restrictive canals, larger, more open canals, or in roots sectioned in two halves. All canals, including the sectioned canals, were prepared with ProTaper files in accordance with the manufacturer's guidelines for use. For narrow canals, the mean values of the generated vertical forces (g) and torque (g.cm) varied from 80 (+/- 20) g (SX) to 232 (+/- 60) g (F2) and from 80 (+/- 24) g x cm (F1) to 150 (+/- 45) g x cm (S2), respectively. For large canals, the mean values of the generated vertical forces (g) and torque (g x cm) varied from 80 (+/- 20) g (SX) to 340 (+/- 20) g (F1) and from 31 (+/- 9) g x cm (S2) to 96 (+/- 35) g x cm (SX), respectively. The SQ varied from 0.93 to 7.95 for narrow canals and from 1.58 to 14.50 for large canals. The SQ is intended to provide values that can be analyzed to predict whether a rotary file will have a tendency to break or will work safely during clinical use. However, if the formula is going to provide useful information, it must index the "rotation to failure torque" with the "mean working torque" at a specific location along the cutting blades of a file. Additionally, this mathematical formula does not account for factors such as the concentration of forces, the way the instruments are used, or the wear of the instruments. A precise protocol for canal preparation should emphasize using small flexible stainless steel hand files to create or verify that within any portion of a root canal there is sufficient space for rotary instruments to follow. When there is a confirmed smooth, reproducible glide path, then a "secured" space exists to safely guide the more flexible terminal extent of a rotary NiTi file. Endogrammes provide an innovative approach to the analysis of mechanical preparations and suggest that the ProTaper shaping files are best used with lateral forces to decrease the coronal screwing effect. The ProTaper finishing files should be used with slow penetration and be introduced only into canals that have a confirmed smooth and reproducible glide path. When any part of the overall length of a canal has been secured, then the number of instruments, the time spent utilizing each instrument, and the overall time progressing through a sequence of instruments to shape this region of the canal is reduced.