Pediatric Rheumatology Online Journal → June 2003 → Miscellaneous Topics→ Abstract #81

VARIABILITY OF LEG LENGTH DISCREPANCY MEASUREMENT IN JUVENILE IDIOPATHIC ARTHRITIS

S. Campillo,¹ P. Dancey,¹ C. Scarinci,² R. Scuccimarri,¹ K. N. W. Duffy,¹ H. Al-Enezi,¹ M. Geoffrion,¹ M. Cortopassi,¹ G. Taylor,¹ C. M. Duffy.¹

¹Rheumatology, Montreal Children's Hospital, Montreal, Canada; ²Pediatrics, CHUS, Sherbrooke

Objective: To determine the intra- and inter-rater variability in the measurement of leg length discrepancy (LLD) in JIA, and also to determine the extent to which this can be improved upon by a specific technique.
Methods: 24 patients (pts), ages 4-17 (6 oligo, 8 poly, 2 systemic, 2 psoriatic, 4 others, 2 healthy volunteers) and 4 examiners (2 rheumatologists, 1 rheum fellow, 1 physiotherapist) participated. Pts were randomly selected and consecutively assigned to either of two groups of 12. Examiners used a tape measure, measuring from anterior superior iliac spine to medial malleolus. For group 1, examiners used their preferred method. For group 2, examiners were instructed to use a specific technique. Pts were randomly placed in rooms prior to each of two sets of measurements. Each patient was measured once by each examiner during each set. Blinding of the examiners to the identity of the pts was achieved by using drapes so as to expose only the waist and legs, and by having the pts wear identical shorts. Examiners failed to identify the identity of the pts.
Analysis: repeated measures ANOVA.
Results: When the 24 pts were analyzed together, there was no statistically significant variability intra, F=1.47; p=0.2378: inter, F=1.49; p=0.2264. When the 2 groups were analyzed separately, while there was still no significant variability, there was a trend towards a method effect [group 1 (intra), F=1.28; p=0.2983: group 1(inter), F=1.31; p=0.2881: group 2 (intra), F=0.15; p=0.9274: group 2(inter), F=0.56; p=0.6478, as evidenced by a lower F value.
Conclusion: The variance around measurement of LLD in JIA using standard techniques is acceptable; however, the accuracy of measurement needs to be assessed against a gold standard. This evaluation is currently being carried out.