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Updated: Feb 12, 2026
Biomechanical Testing of Murine Tendons
Published on: October 15, 2019
Biomechanical properties of the patellar tendon in children with heritable connective tissue disorders
Jacob K Jensen1, Rie H Nygaard2, Rene B Svensson2
1Institute 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. kildevangen@gmail.com.
Insights
Children with hereditary connective tissue disorders (HCTDs) exhibit reduced patellar tendon material properties, correlating with increased joint laxity. This finding highlights potential biomechanical impairments in pediatric HCTDs.
Area of Science:
- Biomedical Engineering
- Orthopedics
- Pediatric Rheumatology
Background:
- Hereditary connective tissue disorders (HCTDs), including Ehlers-Danlos syndrome and Marfan syndrome, present with overlapping symptoms like hypermobility and tissue fragility.
- Differentiating HCTDs in children from healthy individuals is clinically challenging.
- Understanding the biomechanical underpinnings of HCTDs is crucial for accurate diagnosis and management.
Purpose of the Study:
- To investigate and compare the biomechanical properties of the patellar tendon and joint laxity in children with HCTDs versus healthy controls.
- To assess if altered patellar tendon mechanics correlate with generalized connective tissue abnormalities in pediatric HCTDs.
Main Methods:
- Simultaneous force and ultrasonographic measurements were used to evaluate patellar tendon mechanical properties during isometric ramp contractions.
- Tendon dimensions, including cross-sectional area (CSA), were measured via ultrasonography.
- Children with HCTDs (n=7) were age, BMI, sex, and physical activity matched with healthy controls (n=14).
Main Results:
- Children with HCTDs demonstrated significantly greater joint laxity (Beighton score) compared to controls (P < 0.01).
- While patellar tendon dimensions did not significantly differ, HCTD children showed a trend towards larger CSA (P=0.19).
- Secant modulus was significantly lower in HCTD children at common (27%, P=0.05) and maximum (34%, P=0.02) force, indicating reduced material properties.
Conclusions:
- This study provides the first evidence of diminished patellar tendon material properties (lower secant modulus) in children with HCTDs.
- These altered tendon biomechanics may reflect a generalized impairment of connective tissue mechanics in pediatric HCTDs.
- The findings suggest that patellar tendon biomechanical assessment could aid in understanding and diagnosing HCTDs in children.
Purpose:
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).
Methods:
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.
Results:
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).
Conclusions:
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.
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