Growth Plate Fusion in Girls Based on Bone Age
Growth plates in girls typically fuse completely after bone age 13, with most growth plates closing between ages 14-17 years depending on the specific anatomical location.
Timing of Growth Plate Fusion in Girls
- Complete growth plate fusion in females occurs approximately 2 years earlier than in males, with most growth plates showing complete fusion by age 17 in females 1
- By bone age 13, the process of growth plate closure begins to accelerate in girls, signaling the end of significant linear growth potential 2
- When annual height velocity has slowed to <1.5 cm per year, this indicates that growth plates are likely closing, marking the end of growth potential 2
Anatomical Progression of Growth Plate Fusion
- Growth plate fusion occurs in an ascending order from the foot to the wrist in both boys and girls 1
- In the lower extremities:
- Complete fusion occurs in 75% of the radius, 85% of the femur, 97% of the proximal tibia, 98% of the distal tibia, and 98% of the calcaneus in 17-year-old females 1
- The distal femoral growth plate contributes approximately 70% of femoral growth, with contribution varying from 60% at age 7 to 90% by age 14 in girls 3
- The proximal tibial growth plate contributes about 57% of tibial growth overall, varying from 50% at age 7 to 80% by age 14 in girls 3
Factors Affecting Growth Plate Fusion
- Pubertal development strongly correlates with growth plate fusion (correlation coefficients between 0.514-0.598 for different growth plate sites) 1
- BMI significantly influences growth plate fusion timing, with overweight or obese girls showing increased odds ratio (2.65-8.71) for earlier growth plate fusion compared to normal-weight girls 1
- Physical activity levels do not appear to significantly affect growth plate fusion timing 1
- Delayed puberty (primary amenorrhea) can result in wider growth plates and potentially affect bone mass accrual at maturity 4
Clinical Monitoring Recommendations
- Radiography should be performed every 1-2 years during puberty to confirm growth plates remain open in patients where growth monitoring is clinically important 2
- When annual height velocity slows to <1.5 cm per year, radiography should be performed to check growth plate status 2
- Bone age assessments should be interpreted with caution in patients with certain conditions like achondroplasia 2
Growth Plate Activity in Upper Extremities
- In the upper extremities, approximately 80% of humeral growth occurs at the proximal growth plate, increasing to 90% after age 11 5
- For the ulna, approximately 85% of overall growth occurs at the distal growth plate, increasing to 95% after age 8 5
- For the radius, approximately 80% of overall growth occurs distally, increasing to 90% by age 8 5
Monitoring Growth Plate Changes
- Magnetic resonance imaging can be used to accurately assess growth plate fusion status with high inter-observer agreement (Κ = 0.87-0.94) 1
- Growth plate diameter and volume typically increase during active growth periods, as demonstrated in studies measuring femoral and tibial growth plates over 6-month periods 6