Reliability of Tanner Staging Performed by Orthopedic Sports Medicine Surgeons

Purpose: The treatment of anterior cruciate ligament (ACL) tears in children is controversial because of the potential injury to the growth plate resulting from traditional transphyseal surgery. Some authors recommend Tanner staging as a method to determine the patient's maturity to decide between physeal-sparing or transphyseal surgery. This study examines the accuracy and interobserver and intraobserver reliabilities of Tanner staging performed by orthopedic surgeons. Methods: Twenty-eight photographs representing Tanner stages 1-5 were obtained from a pediatric endocrinologist. Four sports medicine orthopedic surgeons received a tutorial on Tanner staging and independently graded the photographs twice, with a 1-month interval between grading exams. The endocrinologist's grade was considered correct. Intraobserver and interobserver reliabilities were determined. Results: The overall average correct scores were as follows: 53% correct Tanner stages on exam 1 and 59% correct on exam 2. The average results for specific Tanner stages were as follows: Tanner stage 1 = 62% correct on exam 1, 83% on exam 2; Tanner stage 2 = 60%/65%; Tanner stage 3 = 60%/46%; Tanner stage 4 = 45%/55%; and Tanner stage 5 = 50%/45%. Per examiner, correct grading was as follows: examiner 1 = 39% on exam 1 and 35% on exam 2; examiner 2 = 67%/82%; examiner 3 = 50%/42%; and examiner 4 = 67%/75%. When comparing the grading between exams 1 and 2, examiner 1 changed five answers from correct to incorrect; four answers from incorrect to correct; and two answers from incorrect to a different incorrect choice; examiner 2, three/seven/zero; examiner 3, six/four/one; and examiner 4, two/four/zero. Conclusions: Preoperative Tanner staging performed by orthopedic surgeons is unreliable with large intraobserver and interobserver variabilities. Therefore, relying on Tanner staging as a method to guide decision making for surgery in skeletally immature patients with ACL tears may lead to inadvertent growth plate injury.