Trans-Metaphyseal Screws Placed in Children: An Argument for Monitoring and Potentially Removing the Implants

Background: Surgeons frequently use trans-metaphyseal screws in children to achieve osteosynthesis after fractures or stability after reconstructive osteotomies. Screws that were initially inserted below the cortex of bone can become prominent and symptomatic due to the process of funnelization that narrows the wide metaphysis to the diameter of the thinner diaphysis. Methods: Case series presentation of 11 children who presented with screw prominence after the cutback process range in age from 19 to 169 months. We used the screws as radiographic markers to quantitate the amount of bone "cutback" or lost during the process of funnelization. Results: The average length of screw protrusion beyond the edge of the bone when symptomatic was 8.7 mm (range, 3.3 to 14.3 mm). Time from implantation to the last radiograph averaged 40 months (range, 19 to 84 mo). The average loss of bone width at the time of presentation was 21% (range, 7% to 36%). Conclusions: These cases suggest that orthopaedic surgeons should consider monitoring children after implantation of trans-metaphyseal screws and informing parents and patients about the possibility of screw prominence necessitating removal due to the process of metaphyseal funnelization.