Physiotherapy in Toronto for Knee

Predicting Who Will Respond Positively to McConnell Taping for Knee Pain

Knee pain from patellofemoral pain syndrome (PFPS) can be helped with a simple taping treatment. But not everyone gets pain relief from this technique. In this study, researchers from Taiwan looked for specific factors or patient variables that might account for the success of this treatment.

Patellofemoral Syndrome (PFS) is a condition that causes pain in and around the patella (knee cap). In the normal, healthy adult, the patella moves smoothly up and down over a groove on the femur (thigh bone) as the knee bends and straightens. PFS can develop when the patella is not moving or tracking properly over the femur. This is a common knee problem in teens and young adults (especially runners and athletes) but anyone can be affected.

Taping as a treatment to help realign the patella was first introduced by a physiotherapist by the name of Jenny McConnell. The approach to the problem is used so often now, it is referred to as the McConnell taping technique. But after 20 years of research centered on this technique, there is still much debate and arguing about the best way to treat patellofemoral syndrome. Efforts to use the McConnell taping technique have not always been successful.

A series of studies have been done to help identify when and why McConnell taping works. It has been shown that by holding the patella in place, the taping successfully keeps the knee cap gliding up and down in its own track. Another way in which the taping helps is by sending extra signals through the muscle around the knee cap (the quadriceps muscle). By activating one side of the quadriceps more than the other, the muscle helps pull the patella back in place where it belongs.

But physicians, physiotherapists, and athletic trainers using the McConnell taping suspect there are specific patient factors that play a role in the success of this technique. To find out, 100 patients between the ages of 20 and 60 who had already been diagnosed with patellofemoral pain syndrome (PFPS) were enrolled in this study. They all had the typical pain pattern of PFPS with no history of trauma or injury. Pain with activities like squatting, walking long distances, or going up and down stairs is common with PFPS.

X-rays were taken to determine several important angles (Q-angle,lateral patellofemoral angle, lateral patellar dispacement). These three angles help describe the tilt of the patella, position of the patella, and amount of lateral displacement (placement off to the outside of the patellar track). Other measures used to assess the effectiveness of McConnell taping included age, sex (male or female), and body mass index (BMI).

Before the tape was applied, everyone was asked to step down from an eight-inch high step (leading with the "good" leg first while supporting weight on the painful leg). They rated the pain on a scale from zero (no pain) to 100 (worst or severe pain). One physiotherapist applied the tape to each patient in the study. The technique used was to push the knee cap to the middle where it belongs then apply tape in such a way as to hold it there.

The pain levels were retested after the tape was applied. Paients were placed in two groups. Group one included those who responded to the taping treatment with a reduction in their pain levels (called the responders). Patients in the second group were called the nonresponders. Responders had at least a 20 point change in their pain scores from before to after taping.

By looking at the patient variables for those who responded compared to those who didn't respond, they were able to identify three independent factors that might predict who will have a successful response to McConnell taping. Those three factors included lower body mass index (BMI), smaller lateral patellofemoral angle, and larger Q-angle.

The value of this study is that it verifies how complex patellofemoral syndrome (PFPS) is. It is likely that there is more than one cause and possibly more than one factor present at a time. Earlier studies showed the role of abnormal patellar tracking and abnormal muscle activation as potential causes of PFPS. This study adds a short list of specific patient characteristics that likely contribute to the problem and may help predict patients who will respond to the taping treatment.

These findings still don't explain the exact reason(s) why or how these factors contribute to patient responsiveness to the taping treatment. But the new information will help future researchers explore the underlying mechanisms. The goal is to find effective tresatment for each patient with patellofemoral pain syndrome with long-term relief from painful symptoms.

Reference: Tsung-Yu Lan, MD, et al. Immediate Effect and Predictors of Effectiveness of Taping for Patellofemoral Pain Syndrome. In The American Journal of Sports Medicine. August 2010. Vol.38. No. 8. Pp. 1626-1630.