Ultrasonographic measurement of the distal femoral cartilage thickness in patients with unilateral transtibial amputation

Abstract

Background: Lower limb amputation sometimes predisposes to degenerative secondary disorders.

Objectives: To evaluate the distal femoral cartilage thicknesses of patients with unilateral transtibial amputations using ultrasound and to investigate the relationship between cartilage thickness and disease-related parameters.

Study design: Cross-sectional study.

Methods: Twenty-four unilateral transtibial amputees (mean age: 46.4 ± 8.5 years, range: 28-60 years) were evaluated. Duration of prosthesis use (years) and daily walking time with prosthesis (hours) were recorded. Functional status was assessed by gate velocity (m/s), and 6-min walking distance (m) with prosthesis. Ultrasound was used to measure distal femoral cartilage thicknesses bilaterally at medial/lateral condyles and the intercondylar areas. The percentages of cartilage loss (of the amputee-side in comparison with the nonamputee-side) were calculated.

Results: Compared to the nonamputee-sides, distal femoral cartilage was significantly thinner at lateral condyles and the intercondylar areas on the amputee-sides (p < 0.05). Significant positive correlations were detected between the percentage of cartilage loss (at all three sites of measurement) and gate velocity, 6-min walking distance, and daily walking time with prosthesis (all p < 0.05).

Conclusions: Future prospective controlled studies are warranted to determine the principles of optimum prosthetic use regarding its possible effects on the femoral cartilage of amputee patients.

Clinical relevance: The correlations between the cartilage loss in the amputee extremity with faster gait and longer daily prosthetic use suggest that abnormal gait patterns might increase the loading on the amputated extremity.

Keywords: Transtibial amputation; amputee; cartilage thickness; femur; ultrasonography.