3D intersegmental knee loading in below-knee amputees across steady-state walking speeds

Area of Science:

• Biomechanics
• Orthopedics
• Prosthetics

Background:

• Unilateral below-knee amputees often develop knee comorbidities, but the underlying mechanisms are poorly understood.
• Mechanical knee loading in non-amputees is linked to joint disorders and influenced by walking speed.
• The relationship between amputee knee loading and walking speed remains unidentified.

Purpose of the Study:

• To investigate the three-dimensional mechanical knee loading in unilateral below-knee amputees.
• To compare knee loading patterns between amputees and non-amputees across various walking speeds.
• To identify potential biomechanical factors contributing to knee joint disorders in amputees.

Main Methods:

• Analyzed 14 unilateral below-knee amputees and 10 non-amputee controls.
• Measured intersegmental joint moments and force impulses at four overground walking speeds.
• Utilized repeated-measures ANOVAs to compare knee loading between control, intact, and residual knees.

Main Results:

• No significant differences in joint force impulses were found between intact and control knees.
• The intact knee exhibited lower abduction moment impulse than controls at 0.6 and 0.9 m/s.
• Intact knees showed greater flexion and external rotation moment impulses compared to residual knees across speeds.

Conclusions:

• Intact knees of new amputees without symptoms are not overloaded during walking compared to non-amputees.
• Increased knee loads may arise from prolonged prosthesis use or the onset of joint disorders.
• Further research is needed to assess if identified loading asymmetries impact long-term knee joint health.