Reliability of Radiologic Assessments of Clinically Relevant Growth Remaining in Knee MRI of Children and Adolescents With Patellofemoral Instability: Data From the JUPITER Cohort

Peter D Fabricant; Madison R Heath; Matthew Veerkamp; Simone Gruber; Daniel W Green; Sabrina M Strickland; Eric J Wall; Douglas N Mintz; Kathleen H Emery; JUPITER Study Group; Jacqueline M Brady; Henry B Ellis; Jack Farr; Benton E Heyworth; Jason L Koh; Dennis Kramer; Robert A Magnussen; Lauren H Redler; Seth L Sherman; Marc Tompkins; Philip L Wilson; Beth E Shubin Stein; Shital N Parikh

doi:10.1177/2325967121991110

Reliability of Radiologic Assessments of Clinically Relevant Growth Remaining in Knee MRI of Children and Adolescents With Patellofemoral Instability: Data From the JUPITER Cohort

Orthop J Sports Med. 2021 Apr 13;9(4):2325967121991110. doi: 10.1177/2325967121991110. eCollection 2021 Apr.

Authors

Peter D Fabricant¹, Madison R Heath¹, Matthew Veerkamp¹, Simone Gruber¹, Daniel W Green¹, Sabrina M Strickland¹, Eric J Wall¹, Douglas N Mintz¹, Kathleen H Emery¹; JUPITER Study Group; Jacqueline M Brady¹, Henry B Ellis¹, Jack Farr¹, Benton E Heyworth¹, Jason L Koh¹, Dennis Kramer¹, Robert A Magnussen¹, Lauren H Redler¹, Seth L Sherman¹, Marc Tompkins¹, Philip L Wilson¹, Beth E Shubin Stein¹, Shital N Parikh¹

Affiliation

¹ Investigation performed at Hospital for Special Surgery, New York, New York, USA and Cincinnati Children's Hospital, Cincinnati, Ohio, USA.

Abstract

Background: Surgical decision making and preoperative planning for children and adolescents with patellofemoral instability rely heavily on a patient's skeletal maturity. To be clinically useful, radiologic assessments of skeletal maturity must demonstrate acceptable interrater reliability and accuracy.

Purpose: The purpose of this study was to examine the interrater reliability among surgeons of varying experience levels and specialty training backgrounds when evaluating the skeletal maturity of the distal femur and proximal tibia of children and adolescents with patellofemoral instability.

Study design: Cohort study (diagnosis); Level of evidence, 3.

Methods: Six fellowship-trained orthopaedic surgeons (3 pediatric orthopaedic, 2 sports medicine, and 1 with both) who perform a high volume of patellofemoral instability surgery examined 20 blinded knee radiographs and magnetic resonance images in random order. They assessed these images for clinically relevant growth (open physis) or clinically insignificant growth (closing/closed physis) remaining in the distal femoral and proximal tibial physes. Fleiss' kappa was calculated for each measurement. After initial ratings, raters discussed consensus methods to improve reliability and assessed the images again to determine if training and new criteria improved interrater reliability.

Results: Reliability for initial assessments of distal femoral and proximal tibial physeal patency was poor (kappa range, 0.01-0.58). After consensus building, all assessments demonstrated almost-perfect interrater reliability (kappa, 0.99 for all measurements).

Conclusion: Surgical decision making and preoperative planning for children and adolescents with patellofemoral instability rely heavily on radiologic assessment of skeletal maturity. This study found that initial interrater reliability of physeal patency and clinical decision making was unacceptably low. However, with the addition of new criteria, a consensus-building process, and training, these variables became highly reliable.

Keywords: dislocation; instability; patella; pediatric; physis; physes; skeletal immaturity.