Displaced patella (kneecap) – the knee musculoskeletal complaints and solutions

26-10-2017

If the front hurts – patellofemoral syndrome

The name refers to the joint problem between the kneecap (patella) and the thighbone (femur). Normally, the kneecap fits neatly into the recess on the front surface of the thighbone so both sides are equally burdened. If the shape of the kneecap or the thighbone is different, the load is uneven, which can lead to cartilage damage. The kneecap is held by laterally strong bands. Anatomical abnormalities or insufficient placement of the bands may cause the knee to move in relation to the center line. This is most common in lateral (outward) directions because the bony flange is lower here.

Triggering factors of displacement of the patella

The displacement of the kneecap may be triggered by several factors, but the most typical reason is the overturning of the muscle balance around the knee. Due to the anatomical structure of the knee, several factors are responsible for pulling the knee to the outer side. The only force to compensate is the lower oblique fibers of the quadriceps, which tend to weaken. Accordingly, the mild displacement of the kneecap (patella lateralization) is very characteristic, which greatly increases the risk of knee injury.

Characteristic symptoms

The leading symptom of the problem is the pain of the knee’s front, behind the kneecap, which mainly arises at strong bending: downhill walking, squatting, walking on uneven ground and running. It is a typical symptom when a long sitting period causes a knee pain (“car cinema phenomenon”), because kneecap is heavily compressed into the joint recess when bending, which can provoke pain.

What can cause the displacement of the kneecap?

The predisposing factors include:

abnormal position of the patella (too sideways or located higher than normal)
knee axis deformities (X-foot)
the orthopedic deviations of the foot (flatfoot, bunion, hammer toes)
excessive workout

How to relieve the pain caused by the symptoms?

We can achieve temporary relief of symptoms by relaxing, using painkillers, but long-term results can only be expected from the elimination of causes. In order to restore the muscle balance we primarily need to stretch the outside bands of the knee, which tend to shrink. During muscle strengthening, we need to focus on training the inner part of the thigh muscles (this muscle is very advanced for football players probably due to high kicks in the inner thigh).

The elastic adhesive tape can be used to adjust the position of the kneecap, and the biomechanical correction of knee and leg deviations is important (with special insoles).

If symptomatic treatments do not help

If the kneecap exhibits an abnormal displacement, the most commonly occurring injuries are sprain and fracture. Both involve damage to the surface of the cartilage, which requires more care for their treatment. In the event of a fracture, try to match as closely as possible.

In case of strain, the main problem is the damage of the condyle surfaces, but there may be regular (habitual) patella strain. In such cases, the kneecap may “sideways” out of its place several times a day, and the patient does not visit the doctor, but can place it back. However, this is the rarer case, which usually results from some acquired or congenital deformity of the joint, the axial deviation of the knee joint.

The treatment of the kneecap cartilage is not a simple task, since the space is narrow for the proven cartilage protection process and the bone thickness below the cartilage is very thin (the patella is about 2 cm thick). The lateral release is a commonly used method during which the band supporting the kneecap is cut from the outside, thus ceasing the outward pulling force suppressing the kneecap. The bone can move freely and the pressure on the surface of the cartilage is also reduced. This results in easier, more seamless complaint knee movement. The surgery can be performed from open excavation and arthroscopies.