The plica is an extension of the knee’s synovial capsule, located between the patella (kneecap) and the femur. Plica syndrome is an inflammatory condition of the plica, when it is impinged, or pinched, between the patella and femoral condyle. When the plica becomes inflammed, the symptoms can be mistaken for another painful condition in the same region of the knee called chondromalacia patellae (an inflammation of the underside of the patella, due to softening of the cartilage).
There are 4 synovial plica: (1) Suprapatellar plica, which may cause a secondary suprapatellar bursitis or chondromalacia patellae. (2) Mediopatellar plica (pictured), this is the most frequent site of plica syndrome. (3) Lateral synovial plica, it is less common to have issue or symptoms derived from this structure. (4) Infrapatellar plica, which is the least likely to encounter impingement, and is hardly ever responsible for plica syndrome symptoms.
Signs and symptoms of plica syndrome normally occur secondary to a knee injury or simple repetitive overuse of the joint. There are other less likely causes such as blunt trauma, loose bodies, meniscal tear and Osteochondritis Dessecans (cracks or fragmentation in joint articular cartilage and subchondral bone, due to blood deprivation). There is also a popular theory that the plica is stretched into a “bowstring”, causing it to rub against the medial femoral condyle during repetitive knee flexion, and inflaming both the plica and femoral condyle.
Typical symptoms of plica syndrome are: anterior knee pain, clicking from patellar region, high-pitched snapping and locking/catching of the knee. There is usual aggravation of symptoms with activities such as prolonged sitting, standing, stair climbing and squatting. There is also physical tenderness to the medial and inferior aspect of the patella, and in some cases, a painful and inflammed synovial membrane.
A person with plica syndrome, will have a few options in regards to treatment, based upon the severity of symptoms. The least invasive treatment for this condition involves physical rehabilitation. This will include manual therapy techniques of massage, patellar joint mobilization, lower extremity stretching and strengthening programs and joint supporting assistive devices, such as patellar-knee neoprene braces. Non-steroidal anti-inflammatory medications (NSAIDS), along with the use of ice, are also very effective in symptom management during the chronic inflammation stages of the condition. In addition, the individual will need to significantly decrease the aggravating activities that cause the most significant symptoms.
If less invasive treatment methods are not successful in reducing painful symptoms, then the individual may need to resort to Cortico-steroid injections, to administer a localized dose of steroidal anti-inflammatory medication to the site of tissue inflammation. The final option in treatment of plica syndrome is surgical resection (removal) of the inflammed plica, with documented success rates of 80%, and physical therapy treatments to follow, for the best possible recovery of pain-free knee function.
References: Bigelow, Traci Lee; Plica Syndrome. 6/3/2013; MedScape Reference; Retrieved from: http://emedicine.medscape.com/article/1252011-overview
Shane Hadley, PTA, ATC
ProSport Physical Therapy, 1000 Bristol Street North, Ste. 25, Newport Beach, CA. (949) 250-1112