RSSPatella Femoral Mal-Tracking – The cause & effect debate
July 7, 2009 by David Fitzgerald
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Filed under Knee, Physiotherapy Blog
Much has been written on the pathophysiology of patella femoral pain and hence the multitude of treatment strategies to rehabilitate it.
Of course patella femoral pain is not a single clinical entity but in fact constitutes a spectrum of pathology encompassing the entire extensor mechanism and involving structures such as the quadriceps insertion, the iliotibial band, the retropatellar articular surface, the patella tendon, the infra-patella fat pad and the medial joint line/retaniculum. Each of these distinct anatomical structures show their own inflammatory characteristics and healing response times. The challenge from a therapeutic perspective is to identify:
1) The structures reproducing symptoms.
2) The mechanism underlying the tissue irritation.
3) Rational protocols for effective rehabilitation.
The pioneering work of Jenny McConnell in the 1980′s on this area precipitated an explosion of research evaluating local muscle imbalance around the patella. More specifically the ratio of muscle activity between VMO (Vastus Medialis Obliquus) and the VL (Vastus Lateratus). This conceptual model of patella maltracking suggests as an impairment of dynamic restraint around the patella and has fostered much heated debate and clinical research since originally proposed.
However, the alignment of the patella within the patellar grove is profoundly influenced by lower limb alignment and consequently evaluation of these components must be an integral part of any examination process for extensor mechanism dysfunction.
Both extremes of foot malalignment – namely excessive pronation and excessive supination – by virtue of the torque converter mechanism through the tibia, induce tibial rotation, which essentially changes the patella tendon insertion strain and distorts the relative position of the tibia relative to the femur. Likewise femoral malalignment with respect to the tibia, most notably excessive internal rotation has the effect of lateralising the patella with respect to the vertical and potentially precipitating a sequence of effects along the lateral joint line from lateral retinaculum tightness, fibular head restriction, peroneal nerve vulnerability, medial retinaculum and tibio-femoral joint line overload.
It is therefore incumbent upon treating clinicians to quantify the limb alignment status as accurately as is possible. In my opinion assessment of the tibial and femoral components of lower limb alignment are a clinical priority over the alignment of the patella within the patellar grove. The rational of utilising vastus medialis obliquus contractions (VMO) to realign a lateralised patella when the under lying mechanical dysfunction is a distortion of tibia femoral alignment, is obviously irrational as well as anatomically impossible!. Therefore attempts to quantify patella tilt, prominence or angulation is an exercise in searching for effect rather than cause. US physiotherapist Gary Gray refers to this phenomena as the train on the track. Preoccupation with regard to detail of the patella position (train) without adequate attention to tibiofemoral alignment (track) results in an uncomfortable ride with neither patient nor therapist likely to reach their destination!.
Do you have the tools to adequately assess limb alignment mechanics and the appropriate treatment arsenal to influence recovery?
How do you prioritise your treatment strategy in patello-femoral dysfunction?
Share your thoughts and comments with other therapists.
Rise to the clinical challenge.
David
