Computed Tomography Scanographic Analysis of Symptomatic Limb Length Discrepancy

Limb length discrepancy (LLD) is diagnosed when one limb is noted to be longer than the other. Symptomatic LLD is defined as the appearance of symptoms secondary to the compensatory mechanisms of LLD with a measured limb length differential. Several studies have been conducted analyzing LLD through plain radiographs, yet there are only a few studies analyzing LLD using computed tomography (CT) scanography.

We conducted a retrospective baseline study of patients between December 2007 and December 2017 in order to reinforce the side dominance and associated measurements of lower-extremity limb lengths through CT scanograms. The average femoral, tibial, and total limb length was calculated for each extremity. Paired sample t tests were conducted between each osseous component and total limb length.

Following institutional review board review and exemption, 400 charts that met the inclusion criteria were reviewed. The left limb was significantly longer than the right limb by approximately 0.10 cm (P < .05). The left femur was significantly longer than the right femur by approximately 0.07 cm (P < .05). There was no significant difference in the tibial length (P > .05).

There was a significant limb length differential in which the left limb was longer than the right limb secondary to increased femoral length. Although our results may seem imperative to our understanding of LLD, it is important to state that all of our differentials were similar, with large SDs, indicating low power of the study. Future research with an increased number of participants is warranted to reinforce the findings.