Walking speed and sound limb loading are related to femoral cartilage thickness but not cartilage deformation in those with traumatic lower-limb amputation.

OBJECTIVE: Individuals with lower-limb amputation (LLA) are at high risk for sound knee osteoarthritis (OA) development, presumably due to altered gait mechanics [1]. Yet, few data have linked gait mechanics with direct imaging of sound knee health post-LLA. Here, we evaluated associations between preferred walk speed, sound limb loading and femoral cartilage thickness and strains in those with LLA.

DESIGN: Ten persons with traumatic LLA (Transfemoral:8, Transtibial:2, Age:50.3 ± 15.8 yrs, BMI:27.1 ± 5.9, Time since Amputation: 17.5 ± 14.1 yrs) completed treadmill gait assessments and femoral cartilage ultrasound. Vertical GRFs (1st, 2nd peak), and knee flexion (KFM) and adduction moments (KAM) during treadmill walking at preferred speed were quantified and expressed as absolute (N, Nm) and normalized (%BW, %BW∗Ht). Femoral cartilage ultrasound were captured in the sound knee in max flexion to evaluate trochlear and medial femoral cartilage thickness (MFC) before and after a 15-min walk to evaluate cartilage mechanical function (i.e., strain). Pearsons r were used to evaluate correlations between walk speed, limb loads and cartilage outcomes (α = 0.05).

RESULTS: Walking speed was correlated with resting MFC thickness (r = 0.71, p = 0.03). Larger absolute KFM was moderately correlated (r = 0.66, p = 0.05) with thicker resting trochlear cartilage thickness. No other loading metrics were associated with resting cartilage thickness or cartilage strains.

CONCLUSION: Faster habitual walking speeds and larger absolute KFM were associated with thicker sound limb MFC and trochlear cartilage which may suggest more functionally mobile individuals and higher knee loads exhibit healthier cartilage. Future work should evaluate how mobility and limb loading impacts OA trajectories post-LLA.