The relationship of the angle of immobilisation of the knee to the force applied to the extensor mechanism when partially weight-bearing: a gait-analysis study in normal volunteers

Jones, RK; Khan, WS; Nokes, L; Johnson, DS

Abstract

We describe the influence of the angle of immobilisation during partial weight-bearing on the forces across the extensor mechanism of the knee. Gait analysis was performed on eight healthy male subjects with the right knee in an orthotic brace locked at 0°, 10°, 20° and 30°, with the brace unlocked and also without a brace. The ground reaction force, the angle of the knee and the net external flexion movement about the knee were measured and the extensor mechanism force was calculated.

The results showed a direct non-linear relationship between the angle of knee flexion and the extensor mechanism force. When a brace was applied, the lowest forces occurred when the brace was locked at 0°. At 30° the forces approached the failure strength of some fixation devices. We recommend that for potentially unstable injuries of the extensor mechanism, when mobilising with partial weight-bearing, the knee should be flexed at no more than 10°.

Citation

Jones, R., Khan, W., Nokes, L., & Johnson, D. (2007). The relationship of the angle of immobilisation of the knee to the force applied to the extensor mechanism when partially weight-bearing: a gait-analysis study in normal volunteers. Journal of Bone and Joint Surgery, British Volume, 89-B(7), 911-914. https://doi.org/10.1302/0301-620X.89B7.18452

• Journal Article Type: Article
• Publication Date: Jan 1, 2007
• Deposit Date: Dec 15, 2008
• Journal: Journal of Bone and Joint Surgery - British Volume
• Print ISSN: 0301-620X
• Publisher: British Editorial Society of Bone and Joint Surgery
• Peer Reviewed: Peer Reviewed
• Volume: 89-B
• Issue: 7
• Pages: 911-914
• DOI: https://doi.org/10.1302/0301-620X.89B7.18452
• Publisher URL: http://dx.doi.org/10.1302/0301-620X.89B7.18452