O2154: Relative closure of growth plates in the upper and lower extremity using a serial radiographic collection

Background: Knowing the relative closure pattern of different growth plates can aid clinical decision making in pediatric orthopaedics. For example, the ability to quickly evaluate remaining growth based on closure of physes in the hip and ankle can be helpful with guided growth decision making. Our study uses radiographs obtained from the Bolton-Brush Growth Study Center, which contains annual serial radiographs of all major joints for each subject, allowing us to determine relative order of closure within a single cohort.

Methods: Radiographs of the shoulder, elbow, wrist/hand, hip, knee, and ankle/foot were used to assess individual growth plates using a grade of 0 (open), 1 (incomplete fusion), or 2 (complete fusion). Age at complete fusion was recorded, and linear mixed model analyses were used to compare mean age of closure of upper and lower extremity growth plates by sex.

Results: A total of 3393 radiographs across 699 study visits from 43 females (mean age 12.2 y, range: 3.0 to 18.1 y) and 39 males (mean age 13.2 y, range: 4.0 to 20 y) were included. Average age of closure for the upper and lower extremities were calculated (Table 1). The minimum, 1st quartile, mean, 3rd quartile, and maximum age of complete closure were determined for the upper and lower extremities of males and females (Figure 1). Comparisons were made to key growth plates in each joint.

Conclusion: The order of closure varies slightly by sex, but follows a general progression. In the upper extremity, the olecranon and distal humerus are the first to close, followed by the 5th distal phalanx, the radial head and medial epicondyle, the remaining hand growth plates generally from distal to proximal, the proximal humerus, and, finally, the distal radius and ulna. The lower extremity has greater variability between the sexes, though the following is found in both females and males: the triradiate closes first, followed by the calcaneal apophysis. The distal tibia and proximal femur close prior to the distal femur and proximal tibia. The proximal fibula is last to close. These data may be useful in judging impending growth plate closure in children with radiographs of multiple joints.