Biomedical subjects

M Müller-Gerbl

Publications and source records attributed to M Müller-Gerbl.

42 records · Page 3Linked to original sources

PubMed1987

The thickness of the calcified layer in different joints of a single individual.

The thickness of the articular cartilage and its calcified zone were both measured at specially chosen places in several limb joints from five subjects. The volume of the calcified zone expressed as a percentage of the total cartilage was not only constant for one joint, but also in all the joints of a single individual. Nevertheless, the variation between subjects ranges from 6.9 to 8.6%. In two cases both sides of the body were investigated. As was the case in an earlier investigation on the femoral head, the bilateral distribution of the thickness was the same. Since the thickness of the total cartilage varies with the local distribution of loading in the joint, it follows that the thickness of the calcified layer also depends upon mechanical factors. Five subjects is too few to allow correlation with age or sex to be either refuted or confirmed. There is some evidence in the existing literature that the thickness of the calcified zone may be altered by disease.

Aged↗

PubMed1987

The thickness of the calcified layer of articular cartilage: a function of the load supported?

The thickness of both the articular cartilage and its calcified zone were measured at 25 carefully selected points in 8 human femoral heads, and the ratio of one to the other was found to be remarkably constant for each bone. The thickness of the calcified zone therefore shows the same distribution pattern as that of the total cartilage and, since the latter is dependent upon the distribution of the load, the thickness of the calcified region also appears to be related to mechanical stress. The volume of the calcified zone, however, expressed as a percentage of the total cartilage, varied considerably from one bone to another within the range from 3.23 to 8.8%. Too few specimens were examined to allow correlation with age or sex to be either refuted or confirmed.

Calcification, Physiologic↗

PubMedDate not supplied

[Pathologic glenohumeral stress distribution in calcific tendinosis of the supraspinatus].

AIM: Based on hypothesis that calcific tendonitis of the supraspinatus tendon (CTSSP) could be associated with glenohumeral imbalance, glenohumeral stress distribution was analyzed. METHODS: 26 patient shoulders with CTSSP, unsuccessfully treated by non-operative measures, were examined. A group of 26 macroscopically normal shoulder specimens served as controls. Analysis of glenohumeral stress distribution was indirect evaluating glenoid subchondral bone mineralization by computed tomography osteoabsorptiometry. Density distribution of glenoid subchondral bone mineralization and the position of the two most frequent density maxima were analyzed. RESULTS: Patterns of subchondral mineralization and position of the anterior density maximum were significantly different between both groups. CTSSP mostly presented with a monocentric, anteriorly increased mineralization indicative for a regional increase of stress. The inferior shift of the anterior density maximum demonstrates a parallel shift of glenohumeral stress distribution. CONCLUSION: Mineralization patterns indicate that glenohumeral stress distribution is not physiologic in CTSSP. Moreover, it is comparable with glenohumeral stress distribution as observed in atraumatic antero-inferior glenohumeral instability. Relevance of this observation should be proven for etiology of CTSSP.

Calcification, Physiologic↗

PubMedDate not supplied

[Demonstration of subchondral density pattern using CT-osteoabsorptiometry (CT-OAM) for the assessment of individual joint stress in live patients].

The researches of Pauwels and those following him have demonstrated that the subchondral bone density distribution below the surface of a joint is a metrical parameter which mirrors the predominant stress acting on that joint. Their technique of x-ray densitometry cannot, however, be used during life. By employing computer tomography, a new method has been developed--CT-osteoabsorptiometry (CT-OAM)--which can be used to obtain the density distribution pattern in the living subject. By means of a comparative investigation on specimens which were examined both with traditional x-ray densitometry and with CT absorptiometry, it has been shown that the new method can produce the same results, but providing the great advantage to be used on the living. In addition, the density distribution pattern of the glenoid cavity has been examined in patients with various shoulder conditions, and also in gymnasts who exercise on the rings. The distribution of subchondral bone density showed different patterns in the different groups examined. Both the comparison of the methods and the subsequent study confirmed that CT osteoabsorptiometry enables assessment to be made of the individual long-term stresses acting on a living joint.

Absorptiometry, Photon↗

PubMedDate not supplied

[The distribution of cartilage degeneration of the human patella in relation to individual subchondral mineralization].

According to Pauwels and Kummer the distribution of the subchondral mineralisation can be taken as a measure of the long-term mechanical loading in the joints. Based on a previous study concerning the density distribution of the subchondral bone of the human patella, these results were compared in the following paper with the macroscopically visible cartilage lesions. Degenerative changes on the lateral facet of the patella coincide with regions of high bone mineralisation, those on the "odd facet" on the other hand with areas of low subchondral density. The cartilage lesions on the lateral facet are seen as being due to high and constant mechanical stress, those on the "odd facet" to short infrequent stress-peaks.

Absorptiometry, Photon↗

PubMedDate not supplied

[Distribution pattern of subchondral mineralization in the glenoid cavity in normal subjects, athletes and patients].

To get information on the stresses acting on the shoulder joint, the distribution of subchondral mineralisation was examined by means of CT-Osteo-absorptiometry in the glenoid cavity in healthy people, athletes and patients. In young persons two density maxima are found ventrally and dorsally older persons, however, show a centrally located maximum which suggests a different joint mechanics in different ages depending on the decreasing physiological incongruence. In gymnasts the overall mineralisation is significantly higher, maxima are found centrally or shifted dorsally. In patients with recurrent dislocation of the shoulder or instability the zone of highest density is shifted to the edges of the glenoid cavity indicating that the prevailing position of the resultant force is excentric. By means of CT-Osteo-absorptiometry these individual patterns of mineralisation can be displayed in the living and can give information on the individual mechanical situation ("loading history") of a joint.

Absorptiometry, Photon↗