Article

Unilateral below-knee amputees often develop comorbidities that
include knee joint disorders (e.g., intact leg knee osteoarthritis), with the
mechanisms leading to these comorbidities being poorly understood. Mechanical
knee loading of non-amputees has been associated with joint disorders and shown
to be influenced by walking speed. However, the relationships between amputee
knee loading and speed have not been identified.
This study examined
three-dimensional mechanical knee loading of amputees across a wide range of
steady-state walking speeds. METHODS: Fourteen amputees and 10 non-amputee
control subjects were analyzed at four overground walking speeds. At each speed,
intersegmental joint moment and force impulses (i.e., time-integrals over the
stance phase) were compared between the control, intact and residual knees using
repeated-measures ANOVAs. FINDINGS: There were no differences in joint force
impulses between the intact and control knees. The intact knee abduction moment
impulse was lower than the non-amputees at 0.6 and 0.9 m/s. The intact knee
flexion moment impulses at 0.6, 1.2 and 1.5m/s and knee external rotation moment
impulses at all speeds were greater than the residual knee. The residual knee
extension moment and posterior force impulses were insensitive to speed
increases, while these quantities increased in intact and control knees.
INTERPRETATION: These results suggest the intact knees of asymptomatic and
relatively new amputees are not overloaded during walking compared to
non-amputees. Increased knee loads may develop in response to prolonged
prosthesis usage or joint disorder onset. Further study is needed to determine if
the identified bilateral loading asymmetries across speeds lead to diminished knee joint health.
CI - Copyright (c) 2011 Elsevier Ltd. All rights reserved.

Langue : ANGLAIS