Factors influencing patellar instability in adults with Kaschin-Beck disease and their correlation / 西安交通大学学报(医学版)

ABSTRACT

Objective To study the correlation of patellar stability with age ,knee Kellgren-Lawrence grading and patellar Wiberg typing of adults with Kaschin-Beck disease (KBD) .Methods Through cross-sectional study , we asked 143 adult patients with KBD from several villages in Gansu Province to receive digital radiographic x-ray (DR) which included lateral slice of knee joint and axis slice of patellar .Meanwhile ,each patient had to undergo patellar stability measurement on the DR film which included some indexes such as Insall index , lateral patellofemoral angle ,sulcus angle ,congruence angle ,lateral migrating ratio of patella ,and patellofemoral index . Then ,all the participants were divided into four groups based on the patella Wiberg typing and three groups based on KBD clinical grading .Last ,we analyzed the correlation of patellar stability with patellar Wiberg typing ,clinical KBD grading ,and Kellgren-Lawrence grading of the patients by Spearman test .Results ① By ANOVA test on the patella Wiberg typing ,lateral patellofemoral angle decreased with increased level of patella Wiberg typing ,but congruence angle ,lateral migrating ratio of patella ,and patellofemoral index were increased with increased level of patella Wiberg typing . P values of the six indexes were all <0 .05 ,which indicated that these differences between groups were significant .By ANOVA test on the KBD clinical grading ,lateral patellofemoral angle decreased with increased level of KBD clinical grading ,but congruence angle ,lateral migrating ratio of patella ,sulcus angle ,and patellofemoral index increased with increased level of KBD clinical grading .Besides that P value of Insall index was>0 .05 , P value of the other five indexes were all <0 .05 ,which indicated these differences between groups were significant .② Spearman testa strong correlation lay between Wiberg patellar typing and other indexes including age ,lateral patellofemoral angle ,congruence angle ,lateral migrating ratio of patella ,and patellofemoral index ( R=0 .684 ,0 .752 ,0 .582 ,0 .533 ,0 .735 , P< 0 .05) .However ,there was no correlation between Wiberg patellar typing and K-L photographical grading (R=0 .030 ,P>0 .05) .K-L grading was strongly correlated with age (R=0 .782 , P< 0 .05 ) , weakly correlated with lateral migrating ratio of patella ( R = 0 .104 , P> 0 .05 ) , but not correlated with the others ( R < 0 .1 , P> 0 .05 ) . Age was strongly correlated with K-L grading and lateral patellofemoral angle (R=0 .782 ,0 .506 ,P<0 .05) ,moderately correlated with congruence angle ,lateral migrating ratio of patella ,and patellofemoral index (R=0 .403 ,0 .361 ,0 .475 , P< 0 .05) ,but not correlated with Wiberg typing ,sulcus angle ,or Insall index ( R=0 .024 ,0 .074 ,0 .053 , P>0 .05) .Conclusion Patellar Wiberg typing is the key factor which influences latellar stability ;age has a limited influence ,while K-L grading does not affect patellar stability .