Chondromalacia Patella—Not the Problem
If chondromalacia is the source of AKP, what is it about conservative treatment that “cures” or even improves structurally softened articular cartilage? How can mere activity modification and exercise result in symptom resolution secondary to improvement in cartilage structure? There is no evidence of this occurring. Nevertheless, patients with this “diagnosis” commonly respond to nonoperative treatment.
Dr. Dye has had personal experience in the possible genesis of AKP in CMP. When he was 46 years old, he allowed his asymptomatic knees to be arthroscopically inspected, without intra-articular anesthesia, so that a neurosensory map of their internal components could be drawn (Figure 2).3
More than 18 years after this neurosensory mapping study, both knees are still asymptomatic, despite substantially reduced proteoglycan content of patellar articular cartilage bilaterally, recently detected with T1-ρ magnetic resonance imaging (MRI), the current favorite of many who use MRI to track early osteoarthritis (Figure 4).
Conversely, during the arthroscopy without intra-articular anesthesia, Dr. Dye discovered quickly and dramatically that the synovium and the fat pad were the most sensitive tissues. Light touch on unanesthetized synovial and fat-pad tissues evoked “involuntary verbal exclamations” (Figure 5).3
When MRI of a patient with AKP shows CMP be cautious not to conclude this structural condition is the direct cause of pain. When overload results in loss of homeostasis, breakdown products of damaged articular cartilage can contribute to symptomatic synovial inflammation. In addition, the damaged articular surfaces may fail to efficiently minimize joint friction and load transmission to subchondral bone. Chondromalacia alone, however, cannot be linked to pain.
Malalignment—Not Often the Problem
That brings us to the historically popular concept of patellofemoral “malalignment/maltracking” as a primary cause for AKP. Although this etiology appeals to many in the orthopedic and physical therapy community,5,6 we and others7-10 reject the notion that it is common. What objective malalignment changes occur when a patient becomes asymptomatic without operative treatment? Imaging measures of malalignment do not change significantly after effective treatment. In studying patients with AKP in the mid 1980’s, Dr. Dye found no difference between 104 adults with PFP and 79 age- and activity-matched controls with respect to 9 objective indicators of malalignment, including quadriceps (Q) angle, congruence angle, sulcus angle, and subchondral sclerosis of the lateral patellar facet.
The clinical success of McConnell taping, which often produces instant pain relief by using tape to apply loads to the patella and peripatellar soft tissues, is sometimes cited as evidence that maltracking or malalignment is the cause of the pain. We disagree with that conclusion. This pain relief more likely results from relieving pressure and tension on sensitive soft tissues, including synovial, fat-pad, and retinacular tissues—equivalent to, say, using a finger to pull inflamed and swollen bitten cheek tissues away from the teeth, which might repetitively traumatize them. In both cases, healing is not spontaneous; but relieving the sensitive tissue of the exacerbating load is the common principle. We think subtle changes in the tension and impingement of synovial and fat-pad tissues can have profound effects on AKP. Pain relief with McConnell taping no more proves that the source of the pain is malalignment or maltracking than a finger pulling away inflamed and swollen cheek tissues proves that cheek pain is caused by malocclusion.