Patella instability

Patella instability

Patella or the knee cap is located directly in front of the knee joint and it is a part of it. It is connected to the quadriceps tendon at its proximal part and from its distal part the patellar tendon originates and descends towards the shin bone where it connects to the tuberositas tibiae. Together with these two tendons and the quadriceps muscle the patella forms the extensory mechanism of the knee joint. During knee enxtension the quadriceps tendon pulls the patella upwards and it slides at the distal part of the femur bone.

Patella is stabilized by a number of ligaments that keep her properly positioned and enable her to track straight up and down at the front of the knee without sliding medialy or lateraly. There are the medial and lateral retinaculums (retinaculum medialis et lateralis), tendon tissue originating  from either the medial or lateral quadriceps muscle parts, ie. its tendon tissue. Their roles are to stabilize the patella and the knee joint capsule. The main passive stabilizer of the patella, whose role is also the stabilization of the patelo-femoral joint, is the medial patelo-femoral ligament (MPFL). This ligament keeps the patella in its place, along with the lateral patelo-femoral ligament, by not allowing it to slide inwards or outwards. When either of those ligaments, more commonly the MPFL, gets injured the patella can get dislocated or luxated. In case the MPFL is torn the patella slides lateraly, outwards and it does not slide upwards in the right position during extension. Commonly a patella luxation or instability occurs after an acute MPFL injury, a partialy or completely ruptured MPFL, due to degenerative changes of the patella or knee capsule cartilage or bone tissue, upper leg muscle strenght deficits, medial part of the quaadriceps being too weak in comparison to the lateral part, etc. They are common in car accidents, direct blows or falling on the knee, but they can also occur in daily activities such as squatting, getting out of the car, walking and they can be repetitive, ie, the aptella gets chronically instable, which is in most cases caused by muscle weakness, genetic predisposition or a degenerative change in the bone or cartilage tissue (dysplasia of the patella femur or tibia).

Treatment of patellar instability and luxation can be done conservatively or surgically (MPFL reconstruction). Conservative approach is aimed at reducing the pain and swelling by use of the RICE method (rest, ice, compression, elevation) in the acute phase after the injury has occured and later in the functional phase progressive strenghtening of the medial quadriceps muscle (main active patella stabilizer) as well as hamstrings and gluteal muscles and knee stability exercises should be implemented.

Prevention: timely and proper treatment of earlier knee injuries/damage, equal strenghtening of all upper leg muscles in order to prevent any muscle deficits, stretching of the lateral quadriceps region if it is a bit stronger because in that case it pulls the patella outwards and increases the risk of patella luxation, etc.

Professor Saša Janković, MD PhD, orthopaedic surgery consultant
Rehabilitation program author

Professor Saša Janković, MD PhD, orthopaedic surgery consultant

Professor Saša Janković, MD PhD , orthopaedic surgery consultant. Head of orthopaedic department at the Clinical hospital "Sveti Duh" in Zagreb.

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Duration

30 days

Program duration is 30 days. If you start today on 23.11.2020., the completion of the rehabilitation program will be on 23.12.2020.

Price

US $45.00

Total price is US $45.00 or US $1.50 per program day