Synonyms
Ahlbaeck’s disease
Definition
In medical terminology, the term M. Ahlbäck is used to describe a disease in which extensive bone death (aseptic osteonecrosis) in the area of the lower part of the thigh (femoral condyle) does not occur due to infection. In most cases, the reasons for the occurrence of M. Ahlbäck’s disease are based on a poor blood supply in the lower part of the thigh. This disease mainly affects older people.
To date, hardly any cases of M. Ahlbäck have been observed in children or adolescents. In addition, it can be determined in everyday clinical practice that the affected patients are predominantly women over the age of 60. During the course of the disease, fractures of the necrotic bone tissue occur in M. Ahlbäck. In the long term, this results in a severe deformation of the upper joint surfaces of the knee joint. On the basis of the bone changes, the affected patents can lead to severe postural deformities, which in severe cases can even affect the entire body axis.
Causes for Ahlbäck’s disease
The exact cause for the occurrence of M. Ahlbäck could not be conclusively clarified yet. However, it is certain that a circulatory disorder in the area of the lower thigh bone leads directly to the death (necrosis) of the joint-forming bone tissue. The exact reason for this circulatory disorder is not yet clear.
Symptoms
The symptoms in M. Ahlbäck are quite unspecific and can be assigned to a number of diseases of the joints or bones. In the early stages, M. Ahlbäck’s disease is in many cases completely asymptomatic. This fact makes both an early diagnosis and the timely initiation of therapeutic measures difficult.
In the majority of affected patients, M. Ahlbäck’s disease remains asymptomatic until the first destruction of the bone tissue occurs. With the beginning of the destruction of the bone structures involved in joint formation, pain occurs only during heavy physical strain. At this time, very few patients experience pain under resting conditions.
Even when inspecting (looking at) the knee joint from outside, no changes can be perceived in the early stages. In the course of the disease, however, the affected patients develop increasing joint effusions, which lead to a strong shifting of the kneecap (phenomenon of the dancing patella). After direct pressure on the kneecap, the patella begins to swing up and down on the effusion.
In addition, many of those affected report a pronounced pressure pain on the inside of the knee joint gap. In the further course of the M. Ahlbäck disease, there is a sudden onset of sometimes severe pain in the knee joint. In contrast to the early stages of the disease, these pains occur after some time even under resting conditions.
In addition, many patients report that they also experience these pain phenomena at night. Even the joint effusions, which are not visible from the outside at first, increase significantly over the course of time and become perceptible as severe swelling. In very pronounced forms of Ahlbäck’s disease, the normal range of motion of the knee joint is even restricted.
