Diagnosis by imaging techniques

Sonography (ultrasound) is an easily available and suitable method for detecting knee joint effusion. Depending on the position of a free joint body, this can also be detected. X-rays can detect advanced osteochondrosis dissecans.

Standard a. p. (from the front) and lateral x-rays are usually sufficient. The tunnel image according to Frik is also helpful. The typical changes are most frequently found in the lateral part of the inner thigh roll (femoral condyle).

The x-ray does not provide evidence of the early stages with beginning bone death. The first signs are an oval bone brightening (dark spot) at the described site, which is later limited by a whitish rim (sclerotic zone). The resulting dissociate can eventually detach itself from its composite as a whole or in several small parts.

This can be recognized by the evidence of free joint bodies and a hollow in the knee joint bone. With the MRI (magnetic resonance imaging) of the respective region (e.g. MRI of the knee, MRI of the ankle or MRI of the elbow, etc.) an early diagnosis of osteochondrosis dissecans is possible.

The exclusion of almost all other possible diseases is also important for the diagnosis. The stage of bone death can be determined by MRI, as well as the nutritional situation of the dissecate. The nutritional situation of the dissected bone can also be used to predict the extent to which rejection of the dissected bone is to be feared.

However, it is not possible to determine the exact time of rejection by MRI. Discs that have already been rejected can be reliably detected by MRI. The most precise examination, however, is possible with a knee joint endoscopy (arthroscopy) if the knee joint is affected.

If another joint is present, it can be arthroscopied in the appropriate manner (e.g. ankle joint). The advantage of arthroscopy is that the stability of the OD region can be reliably checked with a tactile hook (loose OD region, very enlarged) and it can be seen whether the cartilaginous surface structure is still intact or whether it is already damaged. In the same session, suitable surgical therapy measures can be carried out.