Every year more than 25,000 knees are replaced in Australia. While surgery is often successful, helping prevent some of the problems that lead to bad knees would be better.
To do this we need to know more about the way various forces affect the knee, says Dr Pazit Levinger, who is using a complex system of gait analysis to learn more about the walking pattern of people with painful knee conditions.
"Preventative measures can then be devised to correct the gait and hopefully prevent deterioration of the joint," she says.
Dr Levinger, a Postdoctoral Research Fellow in La Trobe University’s Musculoskeletal Research Centre, visualises the interplay of forces on patients’ knees using a three-dimensional motion analysis system in combination with computer intelligence. The state-of-the-art equipment helps investigate the recovery of patients after knee surgery, measuring their walking pattern such as joint angles and forces, length of step, step time and stride length.
The research could lead to a greater understanding of what causes deterioration of knees in people over 60 who develop osteoarthritis, a condition in which the cartilage begins to break down and wear away. In severe cases the bones of the knee rub together causing pain, swelling and loss of movement.
"Knee replacement is a most common way of dealing with this and the outcome of surgery is quite good," says Dr Levinger. "It can reduce pain and improve quality of life." In a recent paper published in Gait & Posture, Dr Levinger reported the result of a study that analysed the gait of 11 patients prior to knee replacement surgery and five patients 12 months after surgery.
The research showed surgery restored normal gait in some patients. It detected changes in walking pattern after surgery and indentified abnormal walking patterns. She expects that with further research this type of analysis could be applied more widely in clinical monitoring of recovery.
In people with arthritis of the knee, the force is larger than normal, creating increased load on the knee. "Due to the complexity of the human body, it is not a function of the knee only. One part of the body affects another. How the lower leg segments function is important in understanding the biomechanics of different knee conditions."
"In patellofemoral pain syndrome – which typically affects women and causes pain in the knee cap when they walk upstairs or crouch – it is important to learn more about the relationship between the bones in the leg. For example, if the foot functions differently it changes the forces through the knees," Dr Levinger says. "We think that excessive rolling of the foot puts a load on the knee which can sometimes be resolved with the use of shoe inserts."
(Source: La Trobe University: Gait & Posture: April 2009)