Unilateral versus bilateral clubfoot: an analysis of severity and correlationGray, Kellya,d; Barnes, Elizabethc; Gibbons, Paula,d; Little, Davida,d; Burns, Joshuab,dJournal of Pediatric Orthopaedics B: September 2014 - Volume 23 - Issue 5 - p 397–399 doi: 10.1097/BPB.0000000000000064 Foot & Ankle Abstract Author Information This study compares the severity of unilateral and bilateral clubfoot, and the correlation between right and left feet of bilateral cases. Sixty-six unilateral and 75 bilateral clubfoot patients were assessed for severity using the Pirani score at an average age of 12.9 days (SD 9 days). In bilateral cases, the severity of right and left feet was highly correlated (r=0.68). The odds of being very severe were 2.6 (95% confidence interval 1.3–5.1) times higher in bilateral cases (P=0.007). Bilateral and unilateral clubfeet present with differing severity. Right and left feet from bilateral cases are highly correlated. Researchers need to address these issues during study design and analysis. aDepartment of Orthopaedic Surgery, The Children’s Hospital at Westmead, The Sydney Children's Hospital Network bPaediatric Gait Analysis Service of NSW, The Sydney Children's Hospital Network cNational Health and Medical Research Council Clinical Trials Centre dUniversity of Sydney, New South Wales, Australia Correspondence to Kelly Gray, Department of Orthopaedic Surgery, The Children’s Hospital at Westmead, Locked Bag 4001, Westmead, NSW 2145, Australia Tel: + 61 2 9845 3369; fax: + 61 2 9845 3685; e-mail: email@example.com © 2014 by Lippincott Williams & Wilkins, Inc.