What is Anterior knee pain / Patellofemoral dysfunction?
Anterior knee pain is the umbrella term to cover a wide range of conditions where there are symptoms from the knee cap (patella) and/or just behind it. When we bend and straighten the knee, the patella glides in a groove on the end of the thigh bone (trochlea groove). The purpose of having a patella is to increase the strength of the quadriceps muscle (thigh muscle).
Anterior knee pain may occur spontaneously although is commonly seen after a traumatic injury to the knee (direct fall onto the knee). 25% of the population will be affected at some time and it is the most common overuse syndrome affecting sports people – although you do not have to be sporty to be affected. It is also a leading cause of chronic knee pain in adolescents (particularly females – chondromalacia patellae)
What causes Patellofemoral dysfunction?
There are a number of factors that contribute to Patellofemoral dysfunction.Pain may arise either from damage to the joint surface (e.g. following a fall) or from the patella moving abnormally in the groove on the thigh bone (patellar maltracking). This causes increased forces on the joint and results in pain, and subsequent joint surface damage. Factors that contribute include weakness of the thigh muscles, tightness of the muscles on the outer aspect or back of the thigh, and flat feet.
What are the symptoms?
The main symptom is pain, which usually starts gradually and progressively worsens over time, often without any history of injury. Pain is localised under or around the knee cap, or the inside aspect of the knee. It is worse when walking up and down stairs, with prolonged sitting or when first getting up from a chair. Clicking or grinding of the knee cap is often present. Both knees may be affected. In its extreme form, Patellofemoral dysfunction can lead to a dislocation of the knee cap if there is severe mal-tracking.
How is patellofemoral dysfunction diagnosed?
Patellofemoral dysfunction is usually diagnosed on clinical examination. X-rays and a MRI scan may be required to assess the knee joint.
Can patellofemoral dysfunction be treated without surgery?
Yes. Patellofemoral dysfunction is best treated non-surgically. Physiotherapy is the mainstay of treatment. The aim of physiotherapy is to assist in strengthening the thigh muscles, stretching the tight soft tissues and correcting other factors above and below the knee that contribute to the condition. The knee may be taped into the correct position to assist the knee cap to move more efficiently in the groove on the thigh bone. Although this physiotherapy program is very effective, it needs to be followed diligently for full recovery, which may take more than 6 weeks.
Other non-surgical treatments include ice packs and anti inflammatory medications to treat the symptoms of swelling and inflammation. The goal of treatment is a return to a desired level of activity without pain. Most patients need to refrain from activities that exacerbate the knee pain until strength and flexibility have improved. As symptoms resolve, return to normal sports is encouraged.
What operation may be beneficial?
In rare cases conservative treatment will not be sufficient to alleviate symptoms and surgical options may be considered.
Operations are aimed at alleviating symptoms. Knee arthroscopy may be performed to treat the damaged joint surface causing the pain, or to improve stability of the knee cap in the trochlear groove.