ABSTRACT: There is no clear consensus about which therapies should be used for the various underlying pathologies that lead to patellofemoral problems. The major distinction in classification is between patellofemoral compression syndrome and patellofemoral instability. Patients with the former are concerned primarily with pain; those with the latter have instability or pain or both. Patellar pain may manifest in the parapatellar area or radiate to the back of the knee. Persons' differing activity and conditioning levels may lead to patellofemoral pain variability. Patients with patellar instability include those with recurring frank patellar dislocations and those with symptoms of subluxation. Patients who have patellar instability present with tears of the medial patellofemoral ligament; this is the "essential lesion" for patellar dislocation. (J Musculoskel Med. 2008;25:297-300)
Many classification systems have been devised to help clinicians, both surgeons and nonsurgeons, understand and properly address patellofemoral dysfunction. However, no system has become uniformly accepted. As a result, there is no clear consensus about which therapeutic measures should be used for the various underlying pathologies that lead to patellofemoral problems.
In our opinion, grouping patients with patellofemoral dysfunction according to treatment strategy produces the most practical classification system. The major distinction to be made is between patellofemoral compression syndrome and patellofemoral instability.
Patients with patellofemoral compression syndrome present primarily with pain. They tend to have tight tissue that leads to excessive pressure between the patella and trochlea. Patients usually are treated with nonoperative measures, although operative procedures may be indicated.
Patients with patellofemoral instability complain of instability or pain or both. Instability concerns may manifest as frank patellar dislocation or may be more subtle (eg, a patient with subluxation may feel the knee cap "slip and slide"during activities).Pain complaints are similar to those made by patients who have patellofemoral compression syndrome. First-time dislocation typically is managed nonoperatively if there is no loose body or osteochondral lesion; recurring instability is more likely managed with surgery.
This 3-part article discusses the diagnosis and management of patellofemoral pathology. In this first part, we describe the biomechanics of patellofemoral dysfunction and classification of problems for determining proper treatment. The second part, to appear in a later issue of this journal, will focus on the physical examination. In the third part, we will review various approaches to treatment.
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