The patellofemoral syndrome; the same problem as the Loch Ness Monster?

Receiving a referral letter to see a patient with patellofemoral syndrome causes a feeling of heart-sink in most orthopaedic surgeons. It predicts an unhappy patient, a prolonged clinic appointment, and an unsatisfactory outcome. Especially as a reliable operation is an unlikely management outcome. Orthopaedic surgeons tend to be mechanically minded and see their main task as correcting abnormalities surgically. Patellofemoral syndrome is the antithesis of this. As Teitge said “patellofemoral syndrome: What does it mean? Historically a wastebasket term for pain and dysfunction ... patellofemoral syndrome is not a diagnosis but rather an admission of ignorance” [1]. A medical syndrome is a specific collection of signs, symptoms, laboratory results, and/or imaging findings that occur together often enough, so that the presence of one feature indicates the presence of the others. The causes of a syndrome can be investigated, as can its management and even its cure (consider hypermobility or complex regional pain syndromes). The term “patellofemoral syndrome” is widely used in the orthopaedic literature with many studies analysing patients labelled with this diagnosis. There aremany other terms used to pigeonhole these patients including patellofemoral pain syndrome and chondromalacia patellae [2]. The American Academy of Family Physician has stated that: “Patellofemoral pain syndrome can be defined as retropatellar or peripatellar pain resulting from physical and biochemical changes in the patellofemoral joint. It should be distinguished from chondromalacia, which is actual fraying and damage to the underlying patellar cartilage. Patients with patellofemoral pain syndrome have anterior knee pain that typically occurs with activity and often worsens when they are descending steps or hills. It can also be triggered by prolonged sitting. One or both knees can be affected. Consensus is lacking regarding the cause and treatment of the syndrome.” [3]. But is patellofemoral syndrome really a syndrome? A quick literature search of the term “patellofemoral syndrome” produced 17 recent papers reporting on patients with this problem [4–20]. With respect to the definition of the American Academy of Family Physicians all these papers included anterior knee pain, 11 included activities such as sports, walking or running, 13 included either descending stairs or hills (but none included both), and 14 included prolonged sitting. However 14 also included pain on squatting and kneeling. Furthermore 15 specifically excluded previous trauma. Four of the studies did not appear to fit the American Academy definition [4,10,17,18]. The Loch Ness Monster is a snake-like creature that is said to live in Loch Ness, a large lake in Scotland. Speculation about its existence has gone on for many years, much has been written about it, but it is almost certainly a myth. It is, however, fertile ground for argument and entertainment e.g. is it a surviving plesiosaur? Anterior knee pain is multi-factorial, and the cause of the pain can vary from patient to patient. Over the years, orthopaedic surgeons and physiotherapists