An analysis has been performed of the theories and postulates advanced by von Neumann, London and Bauer, and Wigner, concerning the role that consciousness might play in the collapse of the wave function, which has become known as the measurement problem.
giving out or weakness of the knees can have different causes. These can include problems outside the knee joint itself (weak muscles for example) or inside the knee (torn ligaments or cartilage). See an orthopaedic surgeon to address your individual problem.
However, old knee injuries would be unlikely to cause 'twitching' at the knee, unless by twitching you mean that, when you stand or move, you feel like the knee is 'giving out' or 'catching', in which case these could be a symptom of weakness of the ligaments in the knee.