Joint moment strategies during stair descent in patients with peripheral arterial disease and intermittent claudication.

OBJECTIVE

To determine the lower limb joint kinetic strategies during stair descent in claudicants with peripheral arterial disease (PAD-IC).

DESIGN

Cross-sectional observation study.

SETTING

University laboratory.

PARTICIPANTS

A total of 22 participants; 10 healthy controls and 12 patients diagnosed with PAD-IC.

MAIN OUTCOME MEASURES

Between-group comparisons of ground reaction force (GRF) and, hip, knee and ankle kinetics during steady-state stair descent.

RESULTS

The claudicating-limb group demonstrated reduced vertical and posterior GRF compared to healthy controls (ES = -1.46 [-2.32,-0.69] and ES = -1.08 [-0.42,-0.26]) as well as demonstrating an greater contribution to support moment from the ankle and trends towards a smaller hip contribution (42 ± 14% vs 28 ± 7%, P = .005 and Hip 16 ± 8% vs 21 ± 11%, P = .056, respectively). A unique sub-group was identified within the PAD-IC cohort demonstrating different hip moment strategies during weight acceptance: a novel hip extensor group (PAD-IC HExt) and stereotypical hip flexor group (PAD-IC HFlex). Compared to both healthy controls and the PAD-IC HFlex groups, the PAD-IC HExt group demonstrated increased hip extensor moment (ES = 3.05 [1.67,4.42] and ES = 3.62 [1.89,5.35]) and reduced knee extensor moment (ES = -2.00 [-3.15,-0.85] and ES = -1.36 [-2.60,-0.11] respectively) during weight acceptance.

CONCLUSIONS

A novel hip extensor strategy was identified in a sub-group of claudicants which acts to reduce the demand on the knee extensors, but not the plantarflexors. Weakness in the knee extensors may prevent redistribution of the task demand, typically seen in older adults in stair descent, away from the functionally limited plantarflexor muscle group. Further investigation into multi-level joint strength and the relationship to functional tasks is warranted to inform targeted intervention programmes.