Biomechanical effects of functional knee bracing. Practical implications

Bracing of the anterior cruciate-deficient knee remains controversial. Close review of published data has revealed enough common observations about braces that strong suggestive information can be utilised for clinical purposes until more concrete data are provided. Brace function can vary with design. The primary differences noted are between the shell-type and strap-type braces. Shell braces tend to provide more stability to the knee than do the strap braces. Proper hinge placement, rather than type, affects pistoning and overall performance of the brace. Custom braces provide a better fit than off-the-shelf devices, but they can feel more restrictive, especially the shell braces. Static bench-testing data have shown that these braces provide little stability against anterior tibial translation at forces comparable to athletic play. Yet kinematic and force plate data suggest that they may produce some mechanical constraining effect to the entire lower extremity instead of just the knee joint. The literature still supports the philosophy that functional bracing should be considered as part of a comprehensive rehabilitation programme for an anterior cruciate-deficient athlete with significant functional deficits.     

Joint loading with valgus bracing in patients with varus gonarthrosis

The purpose of this study was to determine whether a brace designed to unload varus degenerative knees actually alters medial compartment loads by decreasing the adduction moment. Eleven patients who had arthrosis confined to the medial compartment were fitted with a valgus brace and tested before and after brace wear with pain and function scoring instruments and by automated gait analysis. The biomechanical data from these patients were compared with those from 11 healthy control subjects. Scores from an analog pain scale decreased 48% with brace wear, and function with activities of daily living increased 79%. Mean adduction moment without the brace measured 4.0 +/- 0.8% body weight times height versus 3.6 +/- 0.8% body weight times height when wearing the brace (10% decrease). The mean adduction moment for control subjects was 3.5 +/- 0.6% body weight times height. Thus, the mean adduction moment decreased from approximately one standard deviation from the normal mean to a value that is similar to the control value. Nine of 11 patients had a decrease in the adduction moment with the brace, five of 11 patients had a reduction higher than 10%, and decreases in this moment were as high as 32%. This study shows that pain, function, and biomechanical knee loading can be altered by a brace designed to unload the medial compartment of the knee.     

The load applied to the foot in a patellar ligament-bearing cast

The purpose of this study was to determine whether a patellar ligament-bearing cast reduces the load applied to a foot in a cast. In a study of ten people who had no history of gait abnormalities, disease involving the motor system, or deformities of the lower extremities, we compared the load applied to the plantar aspect of a foot in a cast (as detected with F-Scan computer-monitored pedobarographic sensors) with the total load that an extremity in a cast receives relative to the ground (as detected with force-plates). Six trials were completed three times by each person. The trials consisted of walking (1) while wearing regular shoes; (2) with a patellar ligament-bearing cast on one leg; (3) with a patellar ligament-bearing cast and an overlying soft knee brace, locked in full extension, on the leg; (4) with only a below-the-knee cast on the leg; (5) with a below-the-knee cast and an overlying knee brace, locked in full extension, on the leg; and (6) with only a knee brace, locked in full extension, on the leg. The loads at peak heel-strike for all three trials were averaged and normalized to body weight. The load on the plantar aspect of the foot, as compared with the total load, was reduced a mean of 11 percent when the patellar ligament-bearing cast was worn alone, and it was reduced a mean of 26 percent when the patellar ligament-bearing cast was used with an overlying knee brace locked in full extension. This difference was significant (p = 0.007). With the numbers available, we could not detect a significant difference between the reduction in load when a patellar ligament-bearing cast was worn alone compared with that when a below-the-knee cast was worn alone or between the reduction when a below-the-knee cast was worn alone compared with that when a below-the-knee cast was used with a knee brace (p = 0.3). In conclusion, we could not demonstrate a significant reduction in the load on the foot when a patellar ligament-bearing cast was used in a traditional fashion; however, a significant (p = 0.007) reduction in load was found when a knee brace locked in full extension was worn in addition to the patellar ligament-bearing cast.     

Allogeneic transplantation of selected CD34+ cells from peripheral blood: experience of 62 cases using immunoadsorption or immunomagnetic technique. Spanish Group of Allo-PBT

Disruption of the anterior cruciate ligament (ACL), a primary stabilizer of the knee, can produce disability. The purpose of our work has been to study the normal ACL in humans, in the presence of normal muscle function and body weight, and develop clinical criteria for reconstruction, establish a basis for rehabilitation programs, and evaluate how knee braces protect this important ligament. The strain behavior of the ACL has been measured by arthroscopic implantation of the Differential Variable Reluctance Transducer while subjects are under local anesthesia. Movement of the knee from a flexed to an extended position, either passively or through contraction of the leg muscles, produces an increase in ACL strain values. Isolated contraction of the dominant quadriceps with the knee between 50 degrees and extension creates substantial increases in strain. In contrast, isolated contraction of the hamstrings at any knee position does not increase strain. With the knee un-weighted, the protective strain shielding effect of a functional knee brace decreases as the magnitude of anterior shear load applied to the tibia increases. A different behavior occurs during weight bearing, the strain shielding effect of the brace remains constant as the magnitude of anterior load increases. Our approach is novel in that it can be used to measure on important portion of the ACLs strain distribution while clinically relevant loads are applied to the knee, subjects perform rehabilitation exercises, or in the presence of different orthoses such as functional knee braces.     

The role of the pulmonary circulation in the regulation of coagulation and fibrinolysis in relation to major surgery

A total of 18 competitive and recreational athletes were enrolled in a randomized, prospective study looking at the effect of pneumatic leg braces on the time to return to full activity after a tibial stress fracture. All patients had positive bone scans and 15 had positive radiographic findings by Week 12. There were two treatment groups. The traditional treatment group was treated with rest and, after 3 pain-free days, a gradual return to activity. The pneumatic leg brace (Aircast) group had the brace applied to the affected leg and then followed the same return to activity guidelines. The guidelines consisted of a detailed functional progression that allowed pain-free return to play. The brace group was able to resume light activity in 7 days (median) and the traditional group began light activity in 21 days (median). The brace group returned to full, unrestricted activity in 21 +/- 2 days, and the traditional group required 77 +/- 7 days to resume full activity. The Aircast pneumatic brace is effective in allowing athletes with tibial stress fractures to return to full, unrestricted, pain-free activity significantly sooner than traditional treatment.     

Purification and characterization of agarases from a marine bacterium, Vibrio sp. PO-303

OBJECTIVE: To examine the relationship of skill, as represented by NCAA division level, to anterior cruciate ligament rupture in collegiate men's and women's basketball and soccer players. DESIGN: Randomized, retrospective. PARTICIPANTS: Women's and men's basketball and soccer players at NCAA Division I, II, and III institutions. MAIN OUTCOME MEASURE: Athletes with or without ACL injury. RESULTS: There was no relationship of ACL injury rate to NCAA division level in men's or women's basketball or soccer. CONCLUSIONS: There are many different variables that contribute to a player's skill level. Although these variables may relate to ACL injury and may be responsible for the differential in injury rate between men and women, skill level as represented by collegiate division does not relate to ACL injury. When considering possible etiologies of the differential in ACL injury rates between men and women, the use of the term "skill" should be avoided, and more specific terms used.     

Solubility properties of racemic praziquantel and its enantiomers

This study was designed to examine both the pattern of team and player efficacy across a season of competition and the relationships among player efficacy, team efficacy, and team performance in collegiate ice hockey. The team and player efficacies of hockey players from 6 teams in a midwestern collegiate hockey league were assessed prior to 32 games. Official game statistics were factor analyzed to produce one useable performance measure, performance outcome. A consensus analysis demonstrated that players held homogeneous beliefs regarding their own and their teams' abilities to perform successfully. A meta-analysis of the regression equations for each team confirmed the homogeneity among teams and the predictive superiority of team efficacy in predicting team performance. Also, when team wins and losses were analyzed across the season, team efficacy significantly increased after a win and significantly decreased after a loss, but player efficacy was not affected.     

A comparative study of TLSO, Charleston, and Milwaukee braces for idiopathic scoliosis

STUDY DESIGN: Retrospective cohort study. OBJECTIVE: To determine which of TLSO, Charleston, or Milwaukee bracing best prevents curve progression and surgery in adolescent idiopathic scoliosis. SUMMARY OF BACKGROUND DATA: Bracing has been shown to prevent curve progression in idiopathic scoliosis, when compared with no treatment. However, there is little literature available comparing the effectiveness of different brace designs. METHODS: One hundred seventy patients who completed brace treatment for adolescent idiopathic scoliosis between 1988 and 1995 were studied. Forty-five thoracolumbosacral orthoses, 95 Charleston braces, and 35 Milwaukee braces were used. Thoracolumbosacral orthoses and Charleston braces were used on comparable curves, whereas Milwaukee braces were used in a subgroup in which the other brace designs were considered inappropriate. Evaluated were the absolute increase in curve severity, the percentage of curves that progressed beyond 6 degrees and 10 degrees thresholds, and the percentage of patients who underwent surgery. RESULTS: Age, Risser stage, curve size, and time braced and observed did not differ among groups. Mean progression of the curve during bracing was 1.1 degrees with thoracolumbosacral orthosis, 6.5 degrees with the Charleston brace, and 6.3 degrees with the Milwaukee brace (P = 0.012; analysis of variance). Proportion of patients with more than 10 degrees of curve progression was 14% with thoracolumbosacral orthosis, 28% with the Charleston brace, and 43% with the Milwaukee brace (P = 0.017; chi-square). The proportion of patients who underwent surgery was 18% with thoracolumbosacral orthosis, 31% with the Charleston brace, and 23% with the Milwaukee brace (P = 0.26; chi-square). CONCLUSIONS: The thoracolumbosacral orthosis was superior at preventing curve progression in adolescent idiopathic scoliosis.     

Perceived team and player efficacy in hockey.

This study was designed to examine both the pattern of team and player efficacy across a season of competition and the relationships among player efficacy, team efficacy, and team performance in collegiate ice hockey. The team and player efficacies of hockey players from 6 teams in a midwestern collegiate hockey league were assessed prior to 32 games. Official game statistics were factor analyzed to produce one useable performance measure, performance outcome. A consensus analysis demonstrated that players held homogeneous beliefs regarding their own and their teams' abilities to perform successfully. A meta-analysis of the regression equations for each team confirmed the homogeneity among teams and the predictive superiority of team efficacy in predicting team performance. Also, when team wins and losses were analyzed across the season, team efficacy significantly increased after a win and significantly decreased after a loss, but player efficacy was not affected. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

四摇杆式液压泥炮机构优化设计

依四摇杆式液压泥炮机构特点,可将其简化为平面杆系进行优化设计。按炮头接近高炉出铁口时的运动轨迹近似为直线与整个机构回转平稳的要求,可分为炮身四杆机构与转炮六杆机构两部分,分别进行优化设计,使此多杆机构优化设计变得简单易行。     

Surgical management of hip dislocation in children with arthrogryposis multiplex congenita

Arthrogryposis multiplex congenita (AMC) is a rare disease with multiple joint contractures. It is widely believed that bilaterally dislocated hips should not be reduced since movement is satisfactory and open reduction has had poor results. Since 1977 we have performed a new method of open reduction using an extensive anterolateral approach on ten hips in five children with AMC. The mean age at surgery was 31.5 months (17 to 64) and the mean follow-up was 11.8 years (3.8 to 19.5). At the final follow-up all children walked without crutches or canes. Two managed independently, one required a long leg brace and two had short leg braces because of knee and/or foot problems. The clinical results were good in eight hips and fair in two and on the Severin classification seven hips were rated as good (group I or group II). We recommend the extensive anterolateral approach for unilateral or bilateral dislocation of the hip in children with arthrogryposis or developmental dislocation of the hip.     

The role of eye and head movements in detecting information about fly balls.

The authors attempted to identify perceptual mechanisms that pick up information for initiating a run to catch fly balls and for judging their landing locations. Fly balls have been shown to be tracked with the eyes and head (R. R. D. Oudejans, C. F. Michaels, F. C. Bakker, & K. Davids, 1999). This raised the question of whether constraining eye and head movements of experienced baseball players by having them wear eye-movement-preventing goggles (eye movements would lead to losing sight of the ball) or a head-movement-preventing neck brace, or both, would limit their capacity (a) to start running in the correct direction and (b) to make correct judgments about the balls' landing locations. Restrictions had minimal effects on response accuracy, but response latency was affected. The goggles increased latency of both running and judging. Moreover, the neck brace decreased judgment time, particularly for difficult balls, suggesting that head stability is important for making judgments. High performance levels suggested that the perceptual system was flexible; that is, different parts of the system can perform the same function. The implications of these findings for perceptual mechanisms are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

高线改造时对原轧辊的综合利用

从降低辊耗的角度出发，通过对比分析高线改造时SMS和MORGAN两种孔型系统的异同点，兼顾改造前后的生产实际情况，对部分符合要求的轧辊提出了新的车削方法，不但满足了现场生产的需求，同时有效地节约了生产成本。     

Braced for impact: reducing military paratroopers' ankle sprains using outside-the-boot braces

BACKGROUND: Ankle injuries account for 30 to 60% of all parachuting injuries. This study was designed to determine if outside-the-boot ankle braces could reduce ankle sprains during Army paratrooper training. METHODS: The randomized trial involved 777 volunteers from the U.S. Army Airborne School, Fort Benning, Ga. Of this group, 745 completed all study requirements (369 brace-wearers and 376 non-brace-wearers). Each volunteer made five parachute jumps, for a total of 3,674 jumps. RESULTS: The incidence of inversion ankle sprains was 1.9% in non-brace-wearers and 0.3% in brace-wearers (risk ratio, 6.9; p = 0.04). Other injuries appeared unaffected by the brace. Overall, 5.3% of the non-brace group and 4.6% of the brace group experienced at least one injury. The risk ratio for injured individuals was 1.2:1 (non-brace to brace groups; p = 0.65). CONCLUSION: Inversion ankle sprains during parachute training can be significantly reduced by using an outside-the-boot ankle brace, with no increase in risk for other injuries.     

Wide tissue distribution of axolotl class II molecules occurs independently of thyroxin

The mouthguard is a resilient device or appliance which is placed inside the mouth to protect against injuries to the teeth, lacerations to the mouth and fractures and dislocations of the jaw. There is clear support in the scientific literature for the use of mouthguards in contact sports such as rugby. Moreover, there is evidence that mouthguards are effective in protecting against concussion and injuries to the cervical spine. There is a high level of acceptance of mouthguards by players and an increasing number are regularly wearing mouthguards. This is especially true among the elite players, but acceptance and wearing rates are moderately high among club players as well. There is strong support among players and researchers for mouthguard wearing to be made compulsory. It is generally recommended that: (i) mouthguards be worn during both practice sessions and games; (ii) the habit of wearing a mouthguard begins at an early age; (iii) mouthguards be regularly replaced while children are still growing; and (iv) adult players replace their mouthguards at least every 2 years. The selection of a mouthguard will depend on a number of factors including the age of the individual, effectiveness and cost. The type I (stock), or 'off-the-shelf', mouthguards are considered inferior when compared with the other available types, and their use is discouraged. Type II (mouth-formed) mouthguards come in 2 forms, the shell-liner version and the popular thermoplastic 'boil and bite' version. While the effectiveness of the shell-liner mouthguard was examined in one experimental study, no such research has been reported for the thermoplastic mouthguard. Type III (custom-fabricated) mouthguards are recommended for players playing in the more vulnerable positions and in the higher grades. Most experimental studies in which the effectiveness of mouthguards has been demonstrated have involved type III mouthguards.     

Intra-articular administration of galactosaminoglucuronoglycan sulfate in moderate primary gonarthritis. A pilot study

BACKGROUND: The present study has been carried out in order to assess the clinical and functional efficacy and tolerability of galactosa-minoglucuronoglycan sulphate (GGGS). The molecule has been intra-articularly administered in patients affected by moderate primary gonarthritis, according to clinical and functional parameters. METHODS: At the beginning and at the end of each period of treatment the following parameters have been evaluated: spontaneous pain, provoked pain, pain during active movement, pain during passive movement, pain at rising (7-8:00 a.m.) pain at bed time (10:00 p.m.), execution time (expressed in seconds) of up-down from a chair (five times), execution time (expressed in seconds) to walk 15 meters. Fifty patients affected by osteoarthritis of the knee were treated weekly, during one year, for two periods of six weeks each with a total amount of 12 injections. RESULTS: Treatment with Galactosaminglucuronoglycan sulphate (GGGS) seems to be effective in the therapy of osteoarthritis of the knee. The pain scores decreased and the functional levels significantly (p < 0.01) improved in a large proportion of patients and GGGS was very well tolerated. CONCLUSIONS: This study suggests that intra-articular treatment is a substantially new way for GGGS administration in the therapy of osteoarthritis of the knee.     

Mechanisms of aortic injury in fatalities occurring in motor vehicle collisions

We analyzed footprints on the surface of a sand dune to estimate maximal running speeds and the incidence of bipedality in nature, as well as to investigate the effects of incline on the escape locomotion of the lizard Callisaurus draconoides. Previous laboratory tests predicted that inclines would negatively affect sprinting performance in C. draconoides. Although physiologists commonly assume that escape locomotion will be near maximal capacity, we found that only 11% of all strides were greater than 90% of maximal speed of C. draconoides. Escape paths averaged 10 m in length and were generally straight. Approximately 30% of the strides taken by C. draconoides were bipedal, and this value was three times greater than previously found for the closely related species Uma scoparia. The modal value of bipedal stride lengths was greater than that for quadrupedal strides. Inclines negatively affected velocity of only the first meter of C. draconoides escape paths. The location of nearest cover had better predictive value for the initial orientation of C. draconoides escapes than incline. On steep slopes (>15 degrees), C. draconoides avoided running directly downhill and uphill and primarily ran horizontally, whereas on shallow slopes, lizards exhibited approximately equal amounts of horizontal, direct uphill, and direct downhill running.     

Differential effects of performance demand and distraction on sexually functional and dysfunctional males.

Sexually functional and sexually dysfunctional male subjects viewed an erotic film while experiencing two different types of distraction. During a neutral distracting condition, subjects were asked to estimate the length and width of a straight line appearing on an adjacent video monitor. During the "performance demand" distraction condition, subjects viewed video feedback of their genital responses and were asked to estimate percentage of full erection. These conditions were compared to a no distraction control condition. Performance demand distraction significantly elevated the responding of functional subjects compared to the neutral distraction condition. The responding of dysfunctional subjects, on the other hand, decreased during the performance demand distraction and was significantly lower than arousal in functional subjects in this condition. Post hoc analyses examined possible cognitive and affective mediating factors of this differential response. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Especial Skills: Their Emergence With Massive Amounts of Practice.

Differing viewpoints concerning the specificity and generality of motor skill representations in memory were compared by contrasting versions of a skill having either extensive or minimal specific practice. In Experiments 1 and 2, skilled basketball players more accurately performed set shots at the foul line than would be predicted on the basis of the performance at the nearby locations, suggesting considerable specificity at this distance. This effect was replicated even when the lines on the court were obscured (in Experiment 2). However, the effect was absent when jump shots were executed in Experiment 3. The authors argue that massive levels of practice at 1 particular member of a class of actions produce specific effects that allow this skill to stand out from the other members of the class, giving it the status of an especial skill. Various theoretical views are proposed to account for the development of these skills. (PsycINFO Database Record (c) 2011 APA, all rights reserved)