Cruciate ligament tear – ‘Swimmer’s knee’ disrupts the sensory motor system

After suffering from tears to the cruciate ligament, patients often feel as if their knee joint is ‘swimming’, although measurements confirm the stability of the knee. Other patients experience the exact opposite: Their knee joint is unstable, but they do not feel any insecurity. A scientific research group from the University of Ulm aimed to find out why patients with a stable knee joint often feel so unsteady.

A series of experiments on 21 patients with tears to the cruciate ligament who had not yet been operated on concluded that there was a disruption to the sensory motor system present in all cases, or in other words, the self-perception of patients was limited. There was no disruption to mechanical stability.

There are 80,000 cruciate ligament tears a year in Germany. Many occur when playing sports – particularly the country's favourite sport, football, but also handball and skiing.
Scientists took electromyographic measurements of the reflex path between the front cruciate ligament and the upper thigh muscles to prove that, in compared with healthy people, it was possible to push the shin bone of the patients in the group further forward. Muscle activity in the thigh behind also slowed down. Unlike patients without the ‘swimming’ sensation, patients with the ‘swimming’ sensation were also able to push their shin bone forward, but muscle activity was slower.

The research group based in Ulm concluded that the patients affected were experiencing a disturbance to their sensory motor system and there was no impairment to knee stability.

Research group from the University of Ulm, Germany:
Dr Mark Melnyk, Dr Michael Faist, Martin Gother, Professor Dr Lutz Claes and Dr Benedikt Friemert

Exercise before operations

Arthritis develops due to wear to the joints. Every strain wears down the cartilage little by little. The joint cavity narrows, the lower leg and thigh bones rub against each other and inflammatory fluid accumulates. A Canadian study (published in New England Journal of Medicine, volume 359, p. 1,097) proves that keyhole surgery on arthritis in the knee joint is no more effective than painkillers and physiotherapy.

As part of the study, the sports doctors examined 172 patients with arthritis in the knee joint. One group underwent a minimally invasive surgical procedure on the knee to flush out the fluid and remove inflamed tissue. The control group did physiotherapy and received pain medication. The doctor re-examined all of the patients two years later. Amazingly, there was no difference between the two groups regarding quality of life, mobility restrictions and pain. This proves that movement therapy delivers the same treatment results.

Doctors recommend moderate movement as a preventive measure for arthritis, as this strengthens the muscles and generates synovial fluid, which nourishes the cartilage. Mobilisation and muscle strengthening help if the joint is already torn. The soft, springy structure of the kyBounder forces the muscles in the feet and legs to constantly remain in motion in order to maintain balance and posture. The result is a unique standing concept that targets the deep layers of muscle. This trains intramuscular coordination and sensory motor skills in a simple yet effective manner.