The Epidemiology and Prognosis of Bilateral Legg-Calve-Perthes Disease :A comparative study with unilateral LCPD Sung-Taek Jung, Ju-Kwon Park, Nam-Young Cho, Sung-Man Rowe Department of Orthopaedic Surgery Chonnam National University Hospital

Introduction Legg-Calve-Perthes disease Most have unilateral involvement Prevalance of bilateral involvement : 8-24% Salter et al, J Bone Joint Surg Am, 1984 Guille JT et al, J Pediatr Orthop, 2002 There was few study on bilateral LCPD Clinical course of bilateral disease has not been evaluated exactly

Purpose To know the epidemiologic difference of unilateral and bilateral Legg-Calve-Perthes disease To evaluate the outcome and prognosis of unilateral and bilateral LCPD

Materials From 1973 to patients were diagnosed as LCPD at our hospital 82 patients presented bilateral LCPD Bilateral group : 82 patients, 69 male, 13 female Inclusion criteria Waldenstrom stage was initial, fragmentation and reossification state They were followed up periodically 69 patients were included 58 male, 11 female 69 patients presented unilateral LCPD Unilateral group : 58 male, 11 female They were randomly selected

Methods Three groups Group A : First affected bilateral LCPD Sex 58 male, 11 female Treatment method Op 9 case, Conservative 60 case Group B : Second affected bilateral LCPD Sex 58 male, 11 female Treatment method Op 5 case, Conservative 64 case Group C : Unilateral LCPD Sex 58 male, 11 female Treatment method Op 18 case, Conservative 51 case

Methods Design Retrospective study Plain radiograph review Hip anteroposterior & frog leg view Reviewed by 2 orthopaedic surgeons Statistic ANOVA test was used to evaluate differences in group A, B and C

Methods Epidemiologic assessment Distribution of sex & age Radiographic assessment Initial Waldenstrom stage Severity Catterall classification Lateral pillar classification Outcome Radiologic Stulberg classification 40 patients(bilateral) and 46 patients(unilateral) were evaluated because of short follow up duration Clinical Pain (VAS), limping, ROM limitation Limb shortening

Result - I Three group Group A : First affected bilateral LCPD Onset age : 6.0 years ( ) Follow up duration : 11.1 years ( ) Group B : Second affected bilateral LCPD Onset age : 6.8 years ( ) Follow up duration : 11.1 years ( ) Group C : Unilateral LCPD Onset age : 6.1 years ( ) Follow up duration : 11.9 years ( )

Result - II Distribution of Sex & Age No statistically difference between these group

Result - III Waldenstrom Classification – Initial Groupp-value A & B A & C B & C Significant statistically difference between group A & B, B & C No statistically difference between group A & C 2nd hip present more initial finding than other group

Result - IV Waldenstrom Classification – Synchronous vs Metachronous Synchronous and metachronous was classified According to Waldenstrom classification at first visit Onset interval in bilateral LCPD Average interval was 7.4 months ( )

Result - V Catterall Classification - Severity Groupp-value A & B A & C B & C Significant statistically difference between group A & B, B & C No statistically difference between group A & C 2nd hip presented milder finding than other group

Result - VI Lateral pillar Classification - Severity Groupp-value A & B A & C B & C Significant statistically difference between group A & B, B & C No statistically difference between group A & C Class C was few in 2nd affected hip

Result - VII Stulberg Classification - Outcome Groupp-value A & B A & C B & C Significant statistically difference between group A & B, B & C No statistically difference between A & C Class I was much more in 2nd hip

Result - VIII Limping 2nd hip presented less limping than other group Pain 2nd hip presented less pain than other group ROM limitation 2nd hip presented less ROM limitation than other group

Result - IX Limb shortening Groupp-value A & B A & C B & C Statistically difference between group B & C 2nd hip presented less limb shortening

Discussion Prevalance of bilateral involvement In our study 1099 patients were diagnosed by LCPD from 1973 to 2009 Among them bilateral LCPD : 82 patient (7.5%) AuthorJournalPublished year Total patient Bilateral (%) Katz Kemp HS et al Wynne-davies R et al Harrison MHM et al Salter et al Guille JT et al J Mt Sinai Hosp NY Br J Radiol J Bone Joint Surg Br J Bone Joint Surg Am J Pediatr Orthop

Discussion  Onset interval between 1 st and 2 nd hip  Bilateral involvement usually developed within two years of unilateral onset Sakai R et al, J Jpn Paed Orthop Assoc, 1993  In our study, average interval to bilateral involvement was 7.4 months ( )  It wound be due to follow up interval  Our follow up interval was shorter than Sakai R et al

Discussion Severity & Outcome More severe course than unilateral one of Ippolito Higher percentage of severe form Van den Bogaert G et al, J Pediatr Orthop B, 1999 Ippolito E et al, J Bone Joint Surg Br, 1987 Lateral pillar A hips: statistically more in the 2nd side Milder in patients with bilateral involvement Treatment of the first side Protective effect on the second side  unclear Guille JT et al, J Pediatr Orthopt Br, 2002 In our study, second affected hip shows better results in outcome and prognosis

Conclusion Prevalance of bilateral LCPD was 7.5% in our study Prevalance of bilateral LCPD was 7.5% in our study First affected hip First affected hip Similar outcome and prognosis of unilateral Second affected hip Second affected hip Stage : Present more initial stage by Waldenstrom Severity : Present milder finding by Catterall & Lateral pillar Outcome : Present better state by Stulberg Limb shortening : Present less shortening

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