Synonyms
Bone necrosis, bone death, Ahlbäck’s disease, aseptic bone necrosis, articular mouse, dissectate, osteochondritis dissecans, osteonecrosis, OD, dissecting osteochondrosis, osteochondrosis
Definition
Osteochondrosis dissecans (OD) is a disease that occurs frequently during growth and young adulthood and affects the knee joint in approximately 85% of cases. In the course of this disease, bone death occurs close to the cartilage, whereby a piece of cartilage located above the affected bone region can detach from its bond (free joint body joint mouse, dissekat).
Anatomy
The knee joint is formed by the thigh and lower leg bones and the kneecap. Osteochondrosis dissecans mainly affects the femur bone (femur condyles) that forms the joint. Mostly the lateral part of the inner (medial) femoral condyle is affected, but also the outer femoral condyle or the rear surface of the patella can be affected.
- Thigh muscles (Musculsus quadriceps femoris)
- Thigh bone (femur)
- Thigh tendon (quadriceps tendon)
- Kneecap (patella)
- Patellar tendon (patella tendon)
- Patellar tendon insertion (Tuberositas tibiae)
- Shinbone (Tibia)
- Fibula (fibula)
Causes
The cause for the development of osteochondrosis dissecans is largely unknown (ideopathic). One of the existing and most widely accepted theories sees recurrent impulse stress of the knee joint as the cause of the development of osteochondrosis dissecans. According to this theory, it is a mechanical damage to the knee joint, such as can occur in sports during recurring stopping or impact movements. Other theories describe a nutritional and/or circulatory disorder of the knee joint bone, incorrect loading, ossification disorders and genetic influences. However, no theory can really explain osteochondrosis dissecans.
Symptoms of Osteochondrosis dissecans
There is no medical history of osteochondrosis dissecans (anamnesis) that points the way forward. More often it concerns sporty engaged young people and young adults who suffer from the symptoms. In the early phase of osteochondrosis dissecans there are no characteristic symptoms and complaints.
At first, the increasing bone mortality is not noticed. Random findings on x-rays of the knee joint are possible. Later, patients with osteochondrosis dissecans may suffer from stress-related pain in the knee joint.
This pain is uncharacteristic and difficult for the patient to describe. Cartilage degradation products can lead to inflammation of the mucous membrane (synovialitis-synovitis) and joint effusions. Once a joint mouse has finally formed, symptoms such as entrapment and blocking of knee joint movement (inhibition of extension and flexion) may occur.
The mouse can damage the healthy cartilage of the knee joint. Osteochondrosis dissecans disease is classified as pre-arthrosis, i.e. as a consequence of this disease, knee joint arthrosis (gonarthrosis) can develop more rapidly than usual with increasing age. In about 25% of cases, the disease can be bilateral. This does not have to correlate exactly in time.
- Kneecap (patella)
- Joint mouse = free joint body
- Shinbone (Tibia)
- Thigh bone (femur)
- Articular cartilage
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