The relationship of the angle of immobilisation of the knee to the force applied to the extensor mechanism when partially weight-bearing

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 degree, 10 degrees, 20 degrees and 30 degrees, 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 degree. At 30 degrees 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 degrees.

The force applied to the knee extensor mechanism differs between flat-footed and normal subjects during walking

“…Raw data were filtered using a fourth order low-pass Butterworth filter with a cut-off frequency of 6 Hz for kinematic data and 15 Hz for kinetic data [13]. The lower extremity was modeled as a rigid, linked-segment system.…”

“…Knee torque was calculated from the model developed in Visual 3D software. Assuming that in a semistatic situation the two torques of the extensor mechanism and knee are equal (τ em = τ knee ) [2,13], the unknown τ em in Eq. (1) can be replaced by knee torque.…”

Mechanical energy flow analysis in athletes with and without anterior cruciate ligament reconstruction during single-leg drop landing

“…The kinematics of the joints were recorded at a frequency of 100 Hz, employing 36 retro-reflective markers placed strategically on specific anatomical landmarks such as the anterior superior iliac spine (ASIS) and posterior superior iliac spine (PSIS), femoral condyles and malleoli, heels, and the base of the first, second, and fifth metatarsals. These markers facilitated the determination of joint centers and segments of the lower extremities 27 , 28 . Additionally, four rigid-shell clusters were affixed to the athletes' thighs and legs to monitor the motion of these segments.…”

The Effect of Extension Constraint Knee Bracing on Dynamic Balance, Gait Mechanics, and Joint Alignment

“…One of the primary ways of limiting joint motion during this period is through knee bracing [1,2,7,8]. Previous research has indicated that braces are effective in restricting static knee range of motion, although the metabolic and physiologic cost of walking increases when using a brace [9][10][11][12][13]. However, little is known about how use of a brace alters functional activities such as unilateral balance and gait [14,15].…”