Anterior knee pain (AKP) is reportedly the most common problem affecting the knee and the second most common problem presenting to physiotherapists. Treatment is nearly always conservative. One of the most frequently applied therapeutic interventions is patellar taping, a procedure which has gained almost universal acceptance in the clinical community. Physiotherapists primarily tape the knee to 'correct' patellar position and/or tracking. They do this after making a detailed assessment of patellar position and movement. Or so the theory goes. In reality they are doing no such thing.
Before taping the patella in a particular direction, the clinician must first make the decision that the patella is in need of correction. Research indicates that the techniques used by physiotherapists to assess patellar position and/or tracking are unreliable, invalid and clinically unacceptable, and should not be used as a measurement tool or a basis for treatment decisions (ref).
Nor should the medical/surgical community feel any pretensions to clinical superiority in this area. The majority of clinical and radiographic measurements used by surgeons and rheumatologists to measure patellar position and/or tracking have been shown to have unacceptable reliability and none have ever consistently demonstrated an inextricable relationship with the patient's symptoms.
This will come as no surprise to most clinicians; in practice most clinical assessment procedures rely on the eye, and the majority of radiographic procedures involve the patient lying in a static and non-weightbearing position, one in which the patient rarely complains of symptoms.
But when the tape is applied, what does it actually do to patellar position ? In short, nothing. The vast bulk of research indicates that therapeutic taping has no effect on patellar position. In fact, the research is so overwhelming, it is a mystery how such a notion still prevails. Indeed, it is hard to escape the conclusion that it owes more to the stubborn credulity of clinicians, especially physiotherapists, rather than the guarded dissemination of research. No study has ever found that patellar position - glide, tilt and rotation - is altered by tape across all conditions measured in symptomatic subjects. Not one.
It may not even matter in which direction the clinician attempts to tape the patella. In a recent study, the largest ever on the immediate analgesic effects of patellar taping, it was found that pain was significantly reduced irrespective of the direction in which the patella was taped (ref). In fact, medial patellar taping, the most frequently used method, had significantly less effect on pain than lateral or neutral taping. The authors concluded that the widely practised technical application of tape for the express purpose of mechanically re-aligning the patella had no place in good clinical practice. They suggested that it would be less time-consuming and more effective simply sticking the tape to the front of the knee.
In the very short term, yes. Every single study shows that taping has an immediate beneficial effect on the patient's pain. The mechanism of this effect is unknown. Advocates of taping suggest that apart from altering patellar position, taping may also work by means of facilitation/inhibition of quadriceps components, offloading of peripatellar tissues or patellar compression. Evidence for this is either contradictory or absent.
How much this effect translates in to long term clinical improvement, however, is very much open to question. Whilst several studies have demonstrated the long term beneficial effects of a package of treatment involving patellar taping, there have been only two randomised controlled trials specifically examining the effect of taping over an extended period (ref). These both found that the addition of taping to an orthodox physiotherapy rehabilitation programme had no effect on outcome.
Some people have questioned the importance of all this. Does it matter how tape works, as long as it does (if only in the short term) ? Well, yes, it matters very much. It matters on a scientific basis: it is the job of science to ask these questions and enlarge our knowledge base. It matters on a clinical basis: we need to know whether we are achieving maximum therapeutic effect in the most effective way possible. And it matters on a conceptual basis. This last one may need some elucidation.
AKP is one of the great enigmas of orthopaedics. Its causes are ill understood and the mechanisms of pain unknown. For a long time, the apparent success of medial patellar taping has reinforced the theory that AKP is primarily a condition of lateral malalignment of the patella, even though many studies have demonstrated a poor correlation between AKP and radiographic signs of patellar lateralization. If attempting to tape the patella in a lateral direction is as effective as taping in the medial direction, then perhaps the whole concept of lateral malalignment needs to be reassessed. Certainly, as scientists, as well as clinicians, we are obliged to seek to find out what we do, how we do it and whether we could do it any better. In the common practice of patellar taping, most practitioners fall woefully short of these responsibilities.