The Effect of Multidirectional Loading and Limb on Femoral Cartilage Thickness in Females Using Ultrasound

Previous research has been conducted on femoral cartilage response to unidirectional (single plane) movements such as drop landings, running, and walking. However, no existing research has focused on the response of femoral cartilage to multidirectional movements. Bini (2021) reported a difference in limb response to unidirectional forces. PURPOSE: To determine the effect of multidirectional loading and limb on femoral cartilage thickness using ultrasound. METHODS: Eighteen college-aged, physically active females (aged 18-23) participated in the study. After 45 minutes of femoral cartilage unloading, participants performed 120 drop-landing to cutting movements off of a 46 cm box (60 in each direction) with three landings per minute. Participants landed with each foot on a Kistler force plate (1000 Hz). Ultrasound imaging (Mindray M7) collected scans of both limbs before and after the mutlidirectional loading. Femoral cartilage thickness at the medial condyle (MC), lateral condyle (LC), and intercondylar notch (IC) was measured. For each region, a two factor ANOVA was performed to determine the effect of limb and loading on cartilage thickness (p < 0.05). RESULTS: For the IC thickness, there was only a main effect for load (p = 0.043) with the post-load values being larger than the pre-load values (0.247 ± 0.015 vs. 0.236 ± 0.012 cm). There was no main effect for LC thickness, but an interaction between load and limb (p = 0.002). The left limb values increased (0.214 ± 0.027 to 0.228 ± 0.034 cm) while right limb values decreased (0.217 ± 0.048 to 0.212 ± 0.029 cm). There were no main effects or interactions for MC thickness, however, the values decreased for both limbs after loading. CONCLUSION: Loading did not uniformly alter femoral cartilage thickness. It is possible that the multidirectional loading was absorbed more in one region of the knee than another, leading to a decrease in one region and increases in others. Research funded by the Swenson Summer Research Fellowship Program.