Anterior knee pain (AKP) is not a specific disease, but refers simply to pain experienced around the front part of the knee, and which may arise from any of several conditions, some of which may not even involve the knee itself.
Anterior knee pain is one of the most common of knee complaints, and probably the one where clinicians most frequently fail to understand or fully assess the problem prior to undertaking surgery. It is important that the clinician (usually the physiotherapist in the first instance) understands the various separate problems that can cause pain in the front of the knee, so that the right questions are asked and the rights tests done to determine the exact cause of this particular patient’s pain.
Common Causes
Patellofemoral pain syndrome (PFPS):
Pain behind or around the patella as a result of pain in the joint. Can be provoked by going up stairs, squatting, and sitting for lond periods of time. It is common in adolescents and young adults, but it can occur at any age, specifically to those who are physically active and excercise regularly. Causes of PFPS include - weak muscle strength in the leg, joint hypermobility of the knee, feet problems, knee alignment problems and knee overuse (sporting activities).
Patellofemoral Arthritis:
A form of knee osteoarthritis common among those in middle and older age.
Bursitis:
Perpatellar bursitis (housemaid's knee) - inflammation of a bursa (a small sac of tissue) in the knee.
Infrapatellar bursitis (parson's knee) - inflammation below the patella.
Anserine bursitis - spontaneous medial knee pain together with tenderness of the inferomedial aspect of the joint.
Patellar Tendinopathy:
Otherwise known as jumper's knee, this is a common and painful overuse disorder.
Osgood-Schlatter/Sinding-Larsen-Johansson Disease:
Painful conditions common in physically active adolescents and children. Both diseases are similar but the pain and swelling occur in different places; Osgood-Schlatter disease affects the upper shin and Sinding-Larsen-Johansson disease affects the inferior pole of the patella. Both are aggravated by jumping and kneeling along with sporting activities. The diseases are not serious and tend to go away with time.
Chrondromalacia Patella:
The softening of the articular carilage of the patella. Although this can cause anterior knee pain it may be associated with patellar misalignment.
Hypermobility:
Hyperextension and hyperflexion of the knee, occurs most commonly around puberty.
Patellar Misalignment:
Misalignment of the patellar often paired with damage to the patellofemoral joint.
Bipartite Patella:
Common in adolescence, often comes with pain and tenderness. It is usually without symptoms but can vary in severity and may somtimes need surgical treatment.
Assessment
Assessment should include a full functional assessment of the whole lower limb from foot to lower spine. Clinical examination should exclude plica and rotational deformity of the long bones. Radiological examination should include special views to fully assess the patella and its underlying groove (trochlea) in the femur (thighbone). An X-RAY or MRI scan may be required, the latter being more useful as details of soft tissues are given.
Treatment
Treatment of AKP will depend on the cause, conservative treament is usually be effective enough to not need surgery.
These can include:
- Strengthening of the quads.
- Non-steroidal anti-inflammatory drugs (NSAIDS)
However in some cases when conservative treatment fails it may be required for a patient to have surgery. There are are a number of possible precedures depending on the diagnosis.