Institute of Sports Medicine, Department of Orthopaedic Surgery M, Bispebjerg Hospital and Center for Healthy Aging, Faculty of Health and Medical Sciences, University of Copenhagen, Bispebjerg Bakke 23, 2400, Copenhagen, Denmark.
Section of Rare Diseases, Department of Clinical Genetics, Copenhagen University Hospital, Rigshospitalet, Copenhagen, Denmark.
Eur J Appl Physiol. 2018 Jul;118(7):1301-1307. doi: 10.1007/s00421-018-3862-7. Epub 2018 Apr 5.
Hereditary connective tissue disorders (HCTDs), such as classic Ehlers-Danlos syndrome (cEDS) and Marfan syndrome (MS) share overlapping features like hypermobility and tissue fragility. In clinical practice it remains a challenge to distinguish children and adolescents with HCTD from healthy children. The purpose of this study was to investigate the biomechanical properties of the patellar tendon and joint laxity (Beighton score) in children with HCTDs (n = 7) compared to healthy controls (n = 14).
The mechanical properties of the patellar tendon were assessed using simultaneous force and ultrasonographic measurements during isometric ramp contractions. Ultrasonography was also used to measure tendon dimensions. The HCTD children were matched with 2 healthy controls with regard to age, body mass index (BMI), sex and physical activity level.
The HCTD children had a greater degree of joint laxity (P < 0.01). Although, the patellar tendon dimensions did not differ significantly between the two groups, the HCTD children showed a tendency toward a larger patellar tendon cross-sectional area (CSA) (35%, P = 0.19). Moreover, stiffness did not differ between the two groups, but secant modulus was 27% lower in children with a HCTD (P = 0.05) at common force and 34% lower at maximum force (P = 0.02).
The present study demonstrates for the first time that children with HCTDs have lower material properties (modulus) of their patellar tendon, which may be indicative of general impairment of connective tissue mechanics related to their increased joint laxity.
遗传性结缔组织疾病（HCTD），如经典型埃勒斯-当洛斯综合征（cEDS）和马凡综合征（MS），具有相似的特征，如过度活动度和组织脆弱性。在临床实践中，区分 HCTD 患儿和健康儿童仍然具有挑战性。本研究旨在探讨 HCTD 患儿（n=7）与健康对照组（n=14）髌腱的生物力学特性和关节松弛度（Beighton 评分）。
使用等长斜坡收缩时的同步力和超声测量来评估髌腱的机械特性。超声还用于测量肌腱尺寸。HCTD 患儿与 2 名在年龄、体重指数（BMI）、性别和身体活动水平方面与健康对照组相匹配的健康对照进行比较。
HCTD 患儿的关节松弛度更大（P<0.01）。尽管两组之间髌腱尺寸没有显著差异，但 HCTD 患儿的髌腱横截面积（CSA）更大（35%，P=0.19）。此外，两组之间的刚度没有差异，但在常见力下，HCTD 患儿的割线模量低 27%（P=0.05），在最大力下低 34%（P=0.02）。
本研究首次证明 HCTD 患儿的髌腱具有较低的材料特性（模量），这可能表明与关节松弛度增加相关的结缔组织力学普遍受损。
