Physiological Parameters of Bone Health in Elite Ballet Dancers.
- 作者列表："Lambert BS","Cain MT","Heimdal T","Harris JD","Jotwani V","Petak S","McCulloch PC
:Stress fractures are common among elite ballet dancers whereby musculoskeletal health may be affected by energy balance and overtraining. PURPOSE:To characterize bone health in relation to stress fracture history, body composition, eating disorder risk, and blood biomarkers in professional male and female ballet dancers. METHODS:A single cohort of 112 dancers (M=55, 25±6yr; F=57, 24±6yr) was recruited. All participants underwent bone and body composition measures using dual-energy-xray-absorptiometry (DXA). In a subset of our cohort (M=30, 24±6yr; F=29, 23±5yr), a blood panel, disordered eating screen, menstrual history, and stress fracture history were also collected. Aged-matched Z-scores and young-adult T-scores were calculated for bone mineral density (BMD) and body composition. Independent samples t-tests and Fisher's exact tests were used to compare BMD, Z-scores, T-scores, and those with and without history of stress fractures. A 1x3 ANOVA was used to compare BMD for those scoring 0-1, 2-6, and 7+ using the EAT26 questionnaire for eating disorder risk. Regression was used to predict BMD from demographic and body composition measures. RESULTS:Female dancers demonstrated reduced spinal (42 percentile, 10%T<-1) and pelvic (16 percentile, 76%T<-1) BMD. Several anthropometric measures were predictive of BMD (p<0.05, r=0.65-0.81, SEE=0.08-0.10g/cm, %Error=6.3-8.5). Those scoring >1 on EAT26 had lower BMD than those with a score of 0-1 (p<0.05). CONCLUSIONS:Professional female ballet dancers exhibit reduced BMD, fat mass, and lean mass compared to the general population whereby low BMD and stress fractures tend to be more prevalent in those with a higher risk of disordered eating. Anthropometric and demographic measures are predictive of BMD in this population.
: 应力性骨折在精英芭蕾舞演员中很常见，肌肉骨骼健康可能会受到能量平衡和过度训练的影响。 目的: 在专业男女芭蕾舞演员中描述与应力性骨折史、身体成分、进食障碍风险和血液生物标志物相关的骨骼健康。 方法: 招募 112 名舞蹈演员 (M = 55,25 ± 6 岁; F = 57,24 ± 6 岁) 的单一队列。所有参与者均使用双能 x线吸收测定法 (DXA) 进行骨和身体成分测量。在我们队列的一个子集中 (M = 30,24 ± 6 岁; F = 29,23 ± 5 岁)，血液检查，饮食筛查紊乱，月经史,并收集应力性骨折史。计算骨密度 (BMD) 和身体成分的年龄匹配 Z 评分和年轻成人 T 评分。采用独立样本 t 检验和 Fisher 精确检验比较 BMD 、 Z 评分、 T 评分以及有和无应力性骨折史的患者。使用 EAT26 进食障碍风险问卷，使用 1x3 ANOVA 比较 0-1 、 2-6 和 7 + 评分的 BMD。使用回归来预测来自人口统计学和身体成分测量的 BMD。 结果: 女舞者表现出脊柱 (42 百分位，10% T<-1) 和骨盆 (16 百分位，76% T<-1) BMD 降低。几种人体测量指标可预测 BMD (p<0.05，r = 0.65-0.81，见 = 0.08-0.10 g/cm，% 误差 = 6.3-8.5)。EAT26 评分> 1 者 BMD 低于 0 ~ 1 分者 (p<0.05)。 结论: 专业女芭蕾舞演员表现为 BMD 、脂肪量、与普通人群相比，瘦体重，即低 BMD 和应力性骨折在饮食紊乱风险较高的人群中更普遍。人体测量和人口统计学指标可预测该人群的 BMD。
METHODS:Purpose To determine outcomes of transphyseal ACL reconstruction using a living parental hamstring tendon allograft in a consecutive series of 100 children. Methods One hundred consecutive juveniles undergoing ACL reconstruction with a living parental hamstring allograft were recruited prospectively and reviewed 2 years after ACL reconstruction with IKDC Knee Ligament Evaluation, and KT1000 instrumented laxity testing. Skeletally immature participants obtained annual radiographs until skeletal maturity, and long leg alignment radiographs at 2 years. Radiographic Posterior tibial slope was recorded. Results Of 100 juveniles, the median age was 14 years (range 8–16) and 68% male. At surgery, 30 juveniles were graded Tanner 1 or 2, 21 were Tanner 3 and 49 were Tanner 4 or 5. There were no cases of iatrogenic physeal injury or leg length discrepancy on long leg radiographs at 2 years, despite a median increase in height of 8 cm. Twelve patients had an ACL graft rupture and 9 had a contralateral ACL injury. Of those without further ACL injury, 82% returned to competitive sports, IKDC ligament evaluation was normal in 52% and nearly normal in 48%. The median side to side difference on manual maximum testing with the KT1000 was 2 mm (range − 1 to 5). A radiographic PTS of 12° or more was observed in 49%. Conclusions ACL reconstruction in the juvenile with living parental hamstring tendon allograft is a viable procedure associated with excellent clinical stability, patient-reported outcomes and return to sport over 2 years. Further ACL injury to the reconstructed and the contralateral knee remains a significant risk, with identical prevalence observed between the reconstructed and contralateral ACL between 12 and 24 months after surgery. Level of evidence III (Cohort Study).
METHODS:Purpose The purpose of the study was to investigate the biomechanics of walking and of the knee joint in the acute phase of ACL injury. Methods We examined 18 patients with acute ACL injuries and 20 healthy adults as controls. The biomechanics of the knee joint and of walking was assessed by 5 inertial sensors fixed with special cuffs to the lower back, the lower third of the thigh, and the lower third of the shank of the right and left legs. The movements and temporal characteristics were recorded while the subject was walking 10 m at a comfortable pace. Based on the results of examination, the patients were divided into two groups: with severe function impairment (6 patients) and with moderate function impairment (12 patients). Results It was found that in the first days post-trauma, not only the knee function was reduced, but the function of the entire lower limb as well. This led to a functional asymmetry. The kinematics of movements in the joints changed in accordance with slower walking. The walking became not only slower, but it was also associated with a decreased impact load in the weight acceptance phase. At later dates, the functional impairments were less pronounced. The total range of flexion motion did not exceed 20 degrees in the first group and 55 degrees in the second one. The injured joint developed functional immobilization within the first days post-injury. This was a guarding response by additional muscle strain to prevent unusual and limit physiological movements in the knee joint. The movements in the knee joint while walking were of small amplitude, rocking, and occurred only under load. The amplitude of the main flexion in the swing phase was reduced. Conclusion The stage of an ACL injury should be assessed not only based on the time post-trauma, but also taking account of the functional parameter—the knee range of flexion while walking. According to our findings, the only factor that had influenced the functional condition of the KJ was the duration of joint immobilization after trauma.
METHODS:Purpose Numerous techniques have been described for the tibial-sided graft preparation in anterior cruciate ligament (ACL) reconstruction. The use of less suture material for graft preparation is thought to improve ingrowth and to reduce the risk for infection. At the same time, the suture construct should be strong enough to resist the surgeon’s pull during tensioning of the transplant. Methods In total, 39 fresh-frozen procine deep flexor tendons were used and prepared as four-strand grafts. In the three-suture group ( n = 19), graft preparation was performed using three tibial-sided sutures, with each tendon end sutured separately. In the one-suture group ( n = 20), a modified graft preparation using only one tibial-sided suture was applied. Each sample underwent load-to-failure testing ( N _max) after cyclic pre-loading. To estimate intraoperative tension forces acting on the tibial-sided suture constructs, the maximal tension force of 26 volunteers on such a construct was measured using a load cell. Results The biomechanical testing of the two different suture constructs showed a significantly higher load-to-failure for the three-suture group (711 N ± 91 N) compared to the one-suture group (347 N ± 24 N) ( p = 0.0001). In both groups, the mode of failure was a tear of the suture in all samples. A failure of the suture–tendon interface was not observed in any case. The median maximal tension force on the construct applied by the 26 volunteers was 134 N (range 73–182 N). Conclusion The presented single-suture tendon graft preparation resisted to smaller failure loads than the conventional three-suture technique. However, no failures in the suture–tendon interface were seen and the failure loads observed were far beyond the tension forces that can be expected intraoperatively. Hence, the single-suture graft preparation technique may be a valuable alternative to the conventional technique.