yogabook / pathology / patellar dysplasia

Definition

Patellar dysplasia is usually congenital, rarely traumatic, and can be categorised into types according to Wiberg (sources do not specify a single type):

1. normal patella
2. Hypoplasia of the medial and hyperplasia of the lateral facet, as if the retropatellar fin were shifted slightly to the lateral, possibly with a clearly incongruent medial facet, which absorbs less force due to less surface area
3. Significantly reduced and convex medial facet with only low force absorption on a very small area
4. Hunter’s hat-patella: the patella is displaced to the side or the medial aspect of the patella is essentially missing altogether

In patellar dysplasia, the femoral condyles can also be altered, sometimes in such a way that guidance is largely preserved, sometimes in such a way that it is further impaired. In addition to the Wiberg types, there is also the flat patella, which is characterised by a strongly flattened fin.

Patellar dysplasia can be asymptomatic, but can also cause retropatellar pain, especially after weight bearing. The knee joint may feel unstable and limited mobility is possible. It is not uncommon for audible and palpable crepitation to occur or pain that occurs at rest and improves after movement. Swelling and tenderness are possible. Depending on the type, patellar luxation, chondropathia patellae or the development of retropatellar arthrosis is possible or probable. The diagnosis is confirmed by X-ray or MRI. Conservative treatment involves moderating the load and building up the strength of the relevant muscles, including examination for muscular dysbalances. In patellar dislocation, the vastus medialis of the quadriceps is particularly important, as patellar dislocations almost always occur laterally. An insufficiently pulling vastus medialis clearly favours the occurrence, as does a missing retinaculum patellae transversale mediale.
If necessary, orthoses or a surgical intervention are required in which the ligaments are tightened or a lateral release is performed to create stability. Replacement of the patella with an artificial one is also possible. Sport may be possible, but must take the circumstances into account. Often heavy leg-related weight training, rowing, martial arts are not possible, sometimes running, rehabilitative strength training with weights or machines are indicated.

Cause

1. Genetic
2. Developmental disorders of the patella due to various influences such as incorrect traction of the musculature, muscular imbalances during growth
3. traumatic
4. hormonal influences during growth
5. Overuse

Predisposing

Diagnosis

1. X-ray
2. MRI for precise clarification of the cartilage, ligaments and muscles (injuries?)
3. Clinical testing, medical history
4. Running analysis, EMG if necessary

Symptoms

1. Retropatellar pain on exertion: pulling or cutting, possibly radiating towards the lower leg or thigh. Further flexion under load is the most painful due to the high contact pressure. Downhill or down stairs is also clearly painful
2. Possibly rest pain, which improves with movement
3. crepitations
4. Restriction of movement
5. Possibly swelling that impairs mobility in the knee joint
6. Sensitivity to pressure

Complications

1. Patellar dislocation
2. Chondropathia patellae
3. Retropatellar arthrosis
4. After initial dislocation, damage to the movement apparatus due to asymmetric avoidance behaviour

Therapy

1. Elimination of muscular imbalances and a strength deficit of the vastus medialis, possibly also isolated EMS training
2. Rest, elevation, counting, NSAIDs if necessary
3. Orthosis/brace
4. Sitting without a widely bent knee
5. Strengthening and balancing sports (strength training, cycling, swimming), yoga
6. For significant dysplasia: repositioning osteotomy
7. For significant dysplasia: patellar plasty