Box2D breakable joints

private final Array<Joint> tmpJoints = new Array<Joint>();
private float timestep = 1 / 60f, maxReactionForceLen2 = 1000, maxReactionTorque = 1;

@Override
public void render(float delta) {
    world.getJoints(tmpJoints);
    for(Joint joint : tmpJoints)
        if(joint.getReactionForce(1 / timestep).len2() > maxReactionForceLen2 ||
        joint.getReactionTorque(1 / timestep) > maxReactionTorque)
            world.destroyJoint(joint);
    world.step(timestep, 8, 3);
    // ...
}