The effect of wedged insoles on the lateral thrust of anterior cruciate ligament-insufficient knees.

BACKGROUND

Patients with untreated anterior cruciate ligament insufficiency often develop osteoarthritis. In Japan, laterally or medially elevated insoles have been widely used for the relief of symptoms associated with unicompartmental osteoarthritis of the knee.

HYPOTHESIS

The use of a valgus wedge in the shoe of a patient with anterior cruciate ligament insufficiency will decrease lateral thrust.

STUDY DESIGN

Controlled laboratory study.

METHODS

An accelerometer was used to measure thrust force in 60 control knees and 35 knees with anterior cruciate ligament insufficiency. The sensor was attached to the affected and the control anterior tibial tubercles to record motion in the medial-lateral and perpendicular directions. The lateral thrust immediately after heel strike was measured continuously by a telemeter under stabilized walking conditions. Measurements were made both with and without wedged insoles.

RESULTS

When compared with the control knee, the peak value of lateral acceleration immediately after heel strike was significantly greater in the anterior cruciate ligament-insufficient knees. However, lateral thrust decreased significantly in the anterior cruciate ligament-insufficient knees when a wedged insole was used.

CONCLUSIONS

Use of an insole resulted in a significant decrease in lateral thrust, even in anterior cruciate ligament-insufficient knees.

CLINICAL RELEVANCE

Use of an insole is one possible prophylaxis for osteoarthritis for an anterior cruciate ligament-insufficient knee.