Biomedical subjects

H Anetzberger

Publications and source records attributed to H Anetzberger.

27 records · Page 2Linked to original sources

PubMed1994

[Change in subchondral mineralization after reconstruction of the anterior cruciate ligament of the sheep].

The cruciate ligaments are generally regarded as regulators of the joint kinematics, but also increasingly as a "Sensory organ" regulating the periarticular musculature, which influences the position of the contact surfaces and the direction and magnitude of the resultant forces. Indirectly, therefore, they influence the long-term stress distribution, which is itself reflected in the distribution of the subchondral mineralisation. An experimental investigation was therefore undertaken to see whether, in terms of this distribution, the distribution of the stress alters postoperatively, since this could be regarded as an early cause of degenerative change. We examined the distribution of the subchondral mineralisation of six tibiae from six adult Merino sheep 1 year after anterior cruciate ligament reconstruction with patellar tendon. The contralateral tibia we used as controls. Maximum subchondral mineralisation of both the medial and the lateral joint surfaces in all the control joints was found to be central. In the treated knees, however, the medial joint surface maxima were found to have been displaced towards the dorsomedial edge of the surface in every case. If the density pattern on the control side is accepted as the expression of a normal stress distribution, the distribution patterns on the treated side must indicate a pathologic distribution of stress. Reconstruction of the anterior cruciate ligament is therefore--at least in the animal model--not able to prevent the development of a pathologic stress distribution.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMedDate not supplied

[Extracorporeal shock waves induce ventral-periosteal new bone formation out of the focus zone--results of an in-vivo animal trial].

AIM: It is known that high-energy extracorporeal shock waves, focussed to the intact distal rabbit femur, induce periosteal new bone formation within the focus zone. This study was done to investigate whether there is additionally new bone formation outside of the focus zone, i. e., in the proximal femur, 10 days after shock wave application to the distal rabbit femur. METHOD: 18 adult Chinchilla-Bastard rabbits were randomly divided into three groups (A, B, C; each n = 6). One distal femur of each animal was focussed for shock wave application with different positive energy flux densities (A 1.2 mJ/mm (2), B 0.9 mJ/mm (2), C sham treatment). Only the proximal femur outside the shock wave focus was investigated. Here periosteal new bone formation was evaluated by fluorescent labelling. The maximum thickness was measured by means of computer-assisted image analysis. RESULTS: Maximum ventral-periosteal new bone formation outside the shock wave focus was significantly increased in group A compared to group B (p = 0.007) or group C (p = 0.001). In contrast, the maximum ventral-periosteal new bone formation outside the shock wave focus demonstrated no statistically significant difference in group B compared to group C (p = 1.0). CONCLUSION: Depending from the amount of positive energy flux density applied to distal rabbit femur a significantly increased ventral-periosteal new bone formation results in the proximal rabbit femur outside the shock wave focus.

Animals↗

PubMedDate not supplied

[Mineral analysis of roentgenologically defined calcifications in patients with chronic calcifying tendinitis of the rotator cuff].

AIM: Extracorporeal shockwave application (ESWA) is in clinical use to promote disintegration of symptomatic calcifications of the rotator cuff of the shoulder. However, disintegration of roentgenologically comparable calcifications of the rotator cuff is not always successfull. It is known from urologic stone lithotripsy that the susceptibility for disintegration of stone-like concrements depends on their mineral content. Therefore, in the present investigation the relative contents of calcium and phosphorus in rotator cuff calcifications were determined. METHOD: 39 surgically removed rotator cuff calcifications were analyzed by means of atomic emission spectrometry. RESULTS: The relative content of calcium of the rotator cuff calcifications was found to be 22.3 % +/- 5.7 % (mean +/- SD; 6.8 % - 32.4 %), that of phosphorus as 10.5 % +/- 2.4 % (2.7 % - 14.4 %). The data neither depend on the gender of the patients nor on their age at the time point of surgical removal of the rotator cuff calcifications. CONCLUSION: Roentgenologically comparable calcifications of the rotator cuff demonstrated distinct individual differences concerning the relative contents of calcium and phosphorus. The present results may serve as the first indication that the susceptibility of rotator cuff calcifications for disintegration may depend on their relative contents of calcium and phosphorus.

Adult↗

PubMedDate not supplied

[Open surgical procedures in calcifying tendinitis of the shoulder - concomitant pathologies affect clinical outcome].

AIM OF THE STUDY: Open surgical removal of calcifications in chronic courses of calcifying tendinitis of the shoulder can be combined with acromioplasty. Independent of the surgical procedure not all patients achieve satisfactory surgical results. The aim of the study was to investigate whether preoperatively known epidemiologic, social, clinical and radiologic factors or intraoperative findings might influence the therapeutic outcome. METHODS: Following diagnostic arthroscopy, open removal of the calcifications was done as an isolated procedure (group A, n = 12) or combined with open acromioplasty (group/B, n = 24). Follow-up was 33 months for both groups. RESULTS: Clinical outcomes were comparable in both groups (Group A, 74.9 points; Group B 73.4 points, Constant-Murley score) and independent of gender, age, profession, duration of anamnesis, hospital-stay period, follow-up period, dominance of arm, preoperative Constant-Murley score, calcification morphology and size and acromial type. 20 patients in total achieved a clinical outcome of </= 75 points (Constant-Murley score). 12 of these demonstrated lesions of the rotator cuff and joint cartilage combined with synovialitis. In 6 patients an adverse preoperative Constant-Murley score or the wish to receive a pension was recorded. CONCLUSION: Both surgical procedures lead to overall good and satisfactory clinical results. Below average clinical outcomes are associated with pathologic findings of the glenohumeral joints, adverse preoperative clinical situation or the wish to receive a pension.

Acromion↗

PubMedDate not supplied

[The architecture of the subacromial space after full thickness supraspinatus tears].

AIM: The etiology of rotator cuff tears is multifactorial. An important factor is the damage of the rotator cuff by narrowing of the subacromial space. The purpose of this investigation was to estimate the influence of various metrical parameters on the size of the subacromial space. METHOD: We investigated 161 human macerated scapulae, 36 of them had a known tear of the supraspinatus tendon. All scapulae were photographed in two standard positions from the front and the lateral side. Defined distances and angles were measured using an image analyzing system followed by statistical analysis. RESULTS: Shoulders with a tear of the supraspinatus tendon showed a trend towards higher incidences of hooked acromions. Furthermore we found a significant higher incidence of elongated oval shaped glenoids in the group with supraspinatus tendon tear. In comparison to normal shoulders a significantly smaller distance from the top of the glenoid to the tip of the acromion and a greater distance from the top of the glenoid to the tip of the coracoid process was measured. In addition there was a significantly smaller coracoid angle and a smaller glenoid-spinal angle in this group. CONCLUSION: The width of the subacromial space depends on various parameters. Our data suggest that besides the acromion type the shape of the coracoid, the acromial angle, the spine-scapula angle and the cavitas-spine angle should be taken into account for diagnostic and therapeutic decisions.

Acromion↗

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

Age-related changes of the glenoid labrum in normal shoulders.

A growing number of labral changes are described in the literature. The purpose of this study was to evaluate the glenoid and labrum of normal shoulders at different ages and characterize any apparent age-dependent changes. We analyzed 32 normal cadaveric shoulders with a mean age of 57 years (range, 18-89 years). There were 22 male and 10 female cadavers, with 14 right and 18 left specimens. The shoulders were studied macroscopically, histologically, and radiologically. The radiologic evaluation consisted of an analysis of the subchondral mineralization of the glenoid with the use of computed tomographic osteoabsorptiometry. Macroscopically, there were no statistically significant differences among the age groups. Histopathologically, the labrum showed a significant qualitative and quantitative increase (P <.01) in lesions across all regions with increasing age. In younger individuals, lesions at the 12-o'clock position were the most prevalent, with the incidence increasing with age. The anterosuperior position was the region with the next highest prevalence. This was also the area of the highest stress distribution on the glenoid. Our studies demonstrated clear histopathologic changes of the glenoid labrum that are significantly age-related at specific sites. The earliest changes are seen close to the area of highest stress distribution of the glenoid, which could explain the progressive labral changes with increasing age. Arthroscopically detected changes of the glenoid labrum should be evaluated in the context of age-related changes in normal shoulders.

Adolescent↗

PubMedDate not supplied

Long-term results of high tibial osteotomy for medial osteoarthritis of the knee.

We reviewed retrospectively the results in patients who had undergone one hundred and four high tibial lateral osteotomies. The operations were all performed between 1985 and 1993. Each one of fifty men and forty nine women demonstrated a varus deformity of the knee with a coexistent medial osteoarthritis. Results were reviewed in 49 patients (62 knees) with an average follow-up of 10.2 years (range 6-14 years). Of the remaining 42 patients, 8 were lost to follow-up, 10 had died, and 24 were subsequently treated with total knee arthroplasty at an average 4.7 years after having had a high tibial osteotomy. Clinical results were evaluated using the Hospital for Special Surgery Score (HSS) and the Knee Society Score. Radiographs were systematically analysed to evaluate osteoarthritis and leg axis. Forty four (90 per cent) of the forty nine patients stated the results met their expectations and given the same circumstances, they would have the operation once again. In these patients the knee score results were excellent. The same patients had excellent HSS and Knee Society Scores. Five patients (10 per cent) had a poor result and twenty four patients were treated later by total knee arthroplasty because of pain. The following factors set these patients apart from those with more favorable results: previous arthroscopic debridement, obesity, lateral knee osteoarthritis, insufficient valgus correction, and an age of more than 55 years. High tibial valgus osteotomy provides good pain relief and improved function in carefully selected patients. Our results support this conclusion.

Adult↗

PubMedDate not supplied

Determination of regional bone blood flow by means of fluorescent microspheres using an automated sample-processing procedure.

The determination of regional blood flow utilizing fluorescent microspheres (FMs) is an established method for numerous organs. Recent progress, in particular the automation of sample processing, has further improved this method. However, the FM method (reference sample technique), which allows repetitive measurement of regional organ blood flow, has so far not been used for the determination of blood flow in bone. The aim of the present study was to establish FM for the quantification of regional bone blood flow (RBBF). Female, anesthetized New Zealand rabbits (n = 6) received left ventricular injections of different amounts of FM at six subsequent time points. In order to examine the precision of RBBF determination, two different FM species were injected simultaneously at the sixth injection. At the end of the experiments the femoral and tibial condyles of each hind limb were removed and the fluorescence intensity in the tissue samples was measured by an automated procedure. In an in vitro study we have shown that acid digestion of the crystalline matrix has no effect on the fluorescence characteristics of FM. The determination of the number of spheres per tissue sample revealed that depending on the tissue sample size up to 3 x 10(6) spheres/injection were necessary to obtain about 400 microspheres in the individual bone samples. RBBF values of the tibial and femoral condyles did not differ at various injection intervals. The tibial blood flow values varied between 6.6 +/- 1.1 and 8.5 +/- 1.4 ml/min/100 g and were significantly higher than those of the femur (4.3 +/- 1.1 to 6.0 +/- 1.8 ml/min/100 g). The bone blood flow values obtained by simultaneous injection of two FM species correlated significantly (r = 0.96, slope = 1.06, intercept = 0.05), the mean difference was 0.39 +/- 1.11 ml/min/100 g. Our data demonstrate that the measurement of RBBF by means of FM allows a valid determination of RBBF.

Animals↗