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Biomedical subjects

J Hassenpflug

Publications and source records attributed to J Hassenpflug.

At least 37 records · Page 2Linked to original sources
PubMed2000

Evaluation of water content by spatially resolved transverse relaxation times of human articular cartilage.

Non-invasive assessment of cartilage properties, specifically water content, could prove helpful in the diagnosis of early degenerative joint diseases. Transverse relaxation times T(2) of human articular cartilage (34 cartilage slices of three donors) were measured on a pixel-by-pixel basis in a clinical whole body MR system in vitro. In vivo feasibility to measure quantitative T(2) maps was shown for human patellar cartilage. The relaxation times of cartilage with collagen in the radial zone oriented perpendicular to the magnetic field increased from approximately 10 ms near the bone to approximately 60 ms near the articular surface. Cartilage water content of the tibial plateau and femoral condyles could be determined from the correlation with T(2) (R(2) = 0.71) with an error of approximately 2 wt.%. In vivo, directional variation would need to be considered. If confirmed in vivo, T(2) measurements could potentially serve as a non-invasive tool for the evaluation of the status and distribution of water content in articular cartilage.

Adult↗
PubMed2000

Magnetic resonance arthrography of the acetabular labrum. Macroscopic and histological correlation in 20 cadavers.

We studied the sensitivity and specificity of magnetic resonance arthrography (MRa) for the diagnosis of lesions of the acetabular labrum in 20 cadaver hips. The MRa results were compared with macroscopic and histological findings. We found that the labrum could be satisfactorily delineated by MRa and that large detachments could be identified satisfactorily. The diagnosis of small detachments and degeneration of the labrum was less reliable.

Acetabulum↗
PubMed1999

[MR arthrography of the labrum acetabulare--a radiological-anatomical correlation in 20 cadaveric hips].

PURPOSE: To investigate frequency of acetabular labral lesions in elderly hip joints, and to determine sensitivity and specificity of MR arthrography (MRa) for the detection of these abnormalities. MATERIALS AND METHODS: Twenty cadaveric hip joints were examined by MRa. For MRa, 15 ml of a solution of iodinated contrast solution (Solutrast 300) and Gd-DTPA (100:1) were injected under fluoroscopic guidance. MR imaging was performed on a 1.5 T MR scanner (Vision, Siemens; FOV 16 cm, matrix 256 x 256, fat-suppressed 3D-FLASH). Multiplanar image reconstructions were done perpendicular to the acetabulum in the oblique-coronal, oblique-axial, and radial planes. The labral specimens were examined macroscopically. RESULTS: In 12/20 hips (60%), a labral lesion was found on pathologic examination. In 7 specimens, the labrum was partially or completely detached in the weight-bearing superior region. One flap-like variant of the labrum was seen; in 4 hip joints, the labrum was degenerated (one cystic degeneration). Pathologic findings were confirmed by MRa in 8/12 specimens (sensitivity 67%). All degenerated labra were correctly diagnosed on MRa. Three small labral detachments and the flap-like variant were misinterpreted as being normal. There were no false positive findings (specificity 100%). The accuracy was 80%. Labral lesions were seen in 6/8 and in 6/12 of hips with and without osteoarthritis, respectively. CONCLUSION: MRa is well suited to delineate the acetabular labrum and to diagnose labral abnormalities. Detection of small labral detachments and anatomic variants is difficult and requires some experience. Labral lesions are correlated to osteoarthritis of the hip, but may be frequently seen in the elderly without underlying osteoarthritis.

Acetabulum↗
PubMed1999

Sonographic hip screening and early management of developmental dysplasia of the hip.

The reliability of Graf's technique in diagnosing developmental dysplasia of the hip (DDH) is investigated in this report. In a prospective study, 6,548 neonates were examined clinically and sonographically; 470 children were reexamined at least once. Sonographic alpha angles and radiographic acetabular index (AI) angles were followed up and compared. Results were as follows: 84.6% of the hips were mature; 14.3% were physiologically immature; 1.1% were dysplastic. Of the sonographically dysplastic hips, 63% were clinically normal. Neonatal sonographic hip status was affected by family history, breech delivery, birth weight, and gestational age. At follow-up, none of the primarily mature hips had worsened. Of the type IIa hips, 89% matured spontaneously, and 11% needed abduction. The 68 dysplastic hips had matured after a maximum of 80 days' abduction, with normal alpha and AI angles by the end of treatment. At 1 year, the pitch had deteriorated again in six children. Graf's sonographic technique reliably diagnoses infantile DDH. Regular orthopedic checkups are needed to detect secondary deterioration of dysplastic hips.

Birth Weight↗
PubMed1992

[The femoropatellar gliding motion during active knee stretching. Imaging using motion-triggered MR tomography].

By means of motion-triggered MRT it has been possible for the first time to demonstrate movements in the patello-femoral joint by means of MRT. Patello-femoral movement was studied during active extension of the knee between 30 degrees flexion and complete extension. The knees of 5 normal females and 7 normal males were studied together with 2 women with recurrent lateral patellar luxation. In normal women there was an average 16 degrees (10 to 18 degrees), in men an average of 12 degrees (10 to 14 degrees) of lateralisation of the patella during complete extension of the knee. In 1 patient there was 10 degrees medial displacement of the patella before extension. In 2 knees with recurrent lateral subluxation there was a 20 and 24 degrees displacement of the patella.

Adolescent↗
PubMed1991

[Hinge endoprosthesis of the knee joint. Long-term results based on the Blauth prosthesis].

Knee prostheses of the condylar or hinge type have constructional features that have both advantages and disadvantages. Both types are compromises as a result of different demands. Here we report long-term results with the Blauth prosthesis as an example of the efficiency of the hinge concept. The Blauth prosthesis is constructed according to the low-friction principle without a weight-bearing axis. Load transmission to the bone is accomplished by large interface areas. The sliding bearing of the patella is oriented perpendicular to the transverse axis of rotation. A prospective multicentric study reports on 511 prosthesis with a follow-up between 1 and 15 years. Aseptic loosenings were confirmed in 1.2% of the patients, deep infections in 3.3%. The survival analysis showed a probability of 89% that a prosthesis would not have a deep infection or loosen. A hinged knee prosthesis shows positive long-term results even compared with the condylar types if the relevant principles of construction are adequately considered.

Aged↗
PubMed1991

[CPM treatment of the shoulder joint].

Since Salter's results about experimental continuous passive motion (CPM) there are remarkable, generally positive experiences on CPM-treatment of the knee-joint. Now CPM-experiences on shoulder joints are described based on data from 150 patients during the last six years. Three types of motorized CPM-machines are presented for the treatment of the shoulder joint. At the present time they are components of the so-called "Artromot-System." Indications and applications of the CPM-devices are described. Patients are accepting the new way of treatment promptly, because they could apply the devices during the early postoperative period for hours in a selected range of motion, causing no pain. The duration of the CPM-treatment should be two to four hours a day. As shown by Salter's experimental studies the continuous passive motion enhances the metabolism of a joint, improves the resorption of effusions, and may prevent joint stiffness as well as secondary arthrosis. CPM-treatment can especially be prolonged for outpatients; thus CPM treatment can contribute to shorten the hospital stay and the time of treatment in general showing an economic factor.

Humans↗
PubMed1990

Are unconstrained components essential in total knee arthroplasty? Long-term results of the Blauth knee prosthesis.

For 17 years, the Blauth total knee prosthesis has been implanted with its basic constructional features remaining unchanged. While it is true that the prosthetic components are constrained by a mechanical hinge, load transmission is actually effected in accordance with the low-friction principle through the cup-shaped condylar surfaces. Packing of the prosthesis in the bone is ensured by large load-bearing surfaces and by specific elements intended for rotational stability. In a comprehensive follow-up review, 497 implants were studied over a period of one to 15 years (average, 45 months). Aseptic loosening occurred in only 1.2% of the prostheses, and deep infection was found in 3% of the patients in the follow-up review. According to survival statistics, the probability of finding prostheses without deep infection or loosening after more than ten years is 89%. The efficiency of total knee arthroplasty (TKA) by hinged prostheses should therefore not be judged by the results obtained with the pioneer implants, which date back to the beginnings of TKA. The clinical results obtained clearly demonstrate that there is 90 degrees knee flexion in more than 88% of the implants. A subjective appraisal demonstrated substantially less pain compared with the preoperative findings. Problems originating from the patella were recorded in less than 10%. However, in 1985, an improved prosthetic design was introduced that also provided for the replacement of the posterior surface of the patella and for a proximally extended patellar bearing. The position of the hinge and implant packing remained unchanged. The results obtained so far with the modified prosthetic design are very good.

Biomechanical Phenomena↗
PubMed1986

Presentation of intraosseous vascularization by sequential maceration.

Using the example of a knee joint, an injection-maceration technique used to present the pattern of arterial vessels inside and outside the bone is described. Femur and tibia are fixed in a rigid position by central cemented shafts, after synthetic resin has been injected i.a. into preparations of the thigh. The actual maceration of soft tissue is not done as a single process but in several steps. In this way, breaking of fine vessel ends as a result of mechanical overload is avoided. After the soft tissue has been completely removed, the bone surface is coated with resin, while the articular surface is left uncoated. In the final step the three-dimensional structure of the bone surface and the pattern of the periosteal vessels remain unchanged. The method described allows presentation of intraosseous arterial vessels less than 20 micron in diameter. The results that can be obtained are demonstrated using the example of arterial supply of the patella and of the condyles of the femur.

Arteries↗
PubMedDate not supplied

[2 benign bone lesions in a tubular bone: misinterpretation of clinical and radiological findings].

INTRODUCTION: Bone lesions are common at puberty. Most of them are detected by chance at examination for other reasons. The nonossifying fibroma does not produce any clinical symptoms and normally is diagnosed by chance. A spontaneous healing is discussed. The osteoid osteoma is characterized by its nocturnal pain and relief of pain at therapy with salicylates. Operative procedures are indicated for healing. CASE: A 12-year-old girl presented with radiological signs of a nonossifying fibroma. Because of local radionuclid uptake and clinical symptoms an operative procedure was carried out. Postoperative remaining pain resulted in radiological detection of a nearby osteoid osteoma and local operative therapy. CONCLUSION: Two benign bone lesions at one tubular bone are an extremely rare situation. The clinical symptoms and the radionuclid uptake are misinterpretated and falsely assigned to the nonossifying fibroma. All clinical symptoms and radiological signs have to be correlate correctly with the diagnosis and consecutive therapy in order to avoid a misinterpretation of obvious clear radiological results.

Bone Diseases, Developmental↗
PubMedDate not supplied

[Arterial supply of the femoral condyles].

INTRODUCTION: The most frequent site for aseptic bone necrosis and osteochondrosis dissecans in the human knee joint is the medial femoral condyle. The aim of this study is to analyze the three-dimensional vascularization of the human knee joint and to find out if there are any differences in the blood supply of the medial and lateral femoral condyles which may explain the preponderance of aseptic bone necrosis in the medial side. MATERIAL AND METHODS: The femoral arteries of 14 unfixed lower extremities have been injected with epoxy resin. After documentation of the extraosseous course of the blood vessels the bone was macerated with 10% formic acid. The insertions of tendons and ligaments were investigated by light microscopy and immunohistochemistry. RESULTS: The arterial supply of the lateral femoral condyle originates from the upper lateral geniculate artery, the terminal ends of which penetrate the bone from lateral. Branches of the middle geniculate artery reach the bone from the medial wall of the intertubercular notch. The subchondral bone of the medial femoral condyle draws its blood supply mainly from the descending geniculate artery. Branches of the middle geniculate artery penetrate the medial femoral condyle only in the posterior part of the intercondylar fossa. These posterior vessels do not contribute to the supply of the subchondral bone. In the anterior part of the medial wall of the intercondylar fossa there is the wide femoral insertion of the posterior cruciate ligament. Injection techniques and immunohistochemical investigations show that the fibrocartilage of the chondral apophyseal insertion of the posterior cruciate ligament is avascular and acts as banier which impedes blood vessels to penetrate the bony surface in this region. The subchondral bone adjacent to the femoral insertion of the posterior cruciate ligament receives its blood supply from vessels that penetrate the bone at the medial wall of the medial femoral condyle. The blood vessels which supply the lateral parts of the medial condyle have the longest intraosseous course. The density of vessels within this region is largely reduced. CONCLUSIONS: The region adjacent to the femoral insertion of the posterior cruciate ligament is the most frequent site for osteochondrosis dissecans in the knee joint. Our results show that the arterial supply of the subchondral bone may be considered as a cofactor for the etiology of osteochondrosis dissecans.

Aged↗
PubMedDate not supplied

[Long-term results with cement-free total hip prostheses (Zweymuller)].

AIM OF THE STUDY: The purpose of the study is the evaluation of subjective, clinical and radiological long-term results of cementless total hip replacements with "Zweymüller" stems and various cups. METHOD: 113 of 165 consecutively implanted "Zweymüller" stems have been examined clinically and radiologically as well as assessed for subjective satisfaction by questionnaire, 26 additional patients were analysed by questionnaire only. Thus, the follow-up rate is 85.5% with a mean follow-up period of 8.9 years (range 5-12.2 years) as far as evaluation of subjective information including data on failures is concerned. The follow-up results were rated by the scores of Merle d'Aubigné and Harris and radiolucent lines on the X-rays were analysed. RESULTS: 96% of the analyzed patients stated subjective satisfaction. 101 hips caused no or only little pain. The average Harris Hip Score rose from 47.1 preoperative to 86.8 postoperative, the functional value of Merle d'Aubigné rose from 4.9 to 10.1 (maximum 12 points). The survival rate of the stems after 10 years is 96%, the complication rate is very low. 81% of the stems showed a proximal radiolucent line. 3 different kinds of cups were used, 79% of the polyethylene cups and 8% of the titanium cups, respectively, were loosened or had been explanted at the time of examination. CONCLUSIONS: During an observation period of 12 years, the implantation of the "Zweymüller" stem has very successful results. The proximal radiolucent lines should nevertheless cause concerns about the predominantly distal anchoring of the stem. The long-term survival of the stems is much better than that of the titanium cups.

Adult↗
PubMedDate not supplied

[Primary rotatory stability of hip endoprostheses stems after manual and robot assisted implantation].

AIM: In our study we compared the primary rotatory stability of hip endoprostheses which were implanted with the help of a robot with that of manually implanted stems. METHOD: We examined three different types of prosthesis-stems: Osteolock (Stryker-Howmedica), CBC (Mathys), Excia (Aesculap). Furthermore, we examined two types of prostheses which could not be implanted with a robot (Sl-Plus/Endoplus; Hipstar/Stryker-Howmedica). 10 stems of each prosthesis type were implanted in identical polyurethane foam blocks; 5 of them were implantated manually, 5 with the help of a robot (CASPAR, URS-Ortho). After implantation, a defined rotatory stress was put on the stem with the help of a torquing machine. The torsional moment which was necessary until the stem broke out of the foam was documented with the help of special software. RESULTS: In all types of prostheses the use of the robot system led to a higher rotatory stability compared to the manual group. Among the three tested types of prosthesis stems, the CBC stem is significantly more stable for rotatory forces after robot-assisted implantation compared to the other two types. After manual implantation there was no difference in stability between the different stems. The Zweymüller stem and the Hipstar prosthesis did very well, even in comparison to the robot-implanted group. The results of the Zweymüller stem and the robot-implanted CBC Stem were similar, and a significantly higher rotatory stability of the Hipstar prosthesis compared to every other stem was observed. CONCLUSION: Using a robot, the rotatory stability of hip endoprostheses can be improved. However, the design of the stems seems to be even more important for the stability than the implantation technique.

Arthroplasty, Replacement, Hip↗