Biomedical subjects
Publications and source records attributed to H G Simank.
A prospective experiment was carried out in 40 rabbits in which the blood supply to the patella was interrupted for defined periods from 2 weeks to 6 months. With prolonged ischaemia, there were clear changes in the articular cartilage which were comparable with those seen in human osteoarthritis.
Joint fractures can interrupt the arterial and venous blood supply to the hyaline cartilage. Previous studies revealed effects of venous engorgement and hypertension in the cartilage. In this study the influence of interruption of the blood supply on the development of osteoarthritis was analysed. In a prospective, experimental study in 40 rabbits all vessels in the patella were ligated and the cartilage was investigated after 2, 6, 12, and 24 weeks by transmission electron microscopy. After 2 weeks no degenerative signs were determined. After 6 weeks there were distinct signs of cartilage injury. The degeneration of the hyaline cartilage increased with time. The endpoint of injury was the destruction of the cartilage and necrosis of the chondrocytes, determined after an ischaemic period of 24 weeks. The stages of cartilage degeneration in our trial correspond to the changes that are well known to occur in osteoarthritis. In conclusion, interruption of the blood supply of the patella results in degenerative changes to the joint cartilage. This effects is related to the duration of ischaemia. On the basis of results we recommend early and watertight repositioning of fractured joints not only for biomechanical reasons but also to avoid irrevocable effects of interrupted blood supply on hyaline joint cartilage.
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In total hip arthroplasty extended approach, simplified luxation and improved exposure are the major advantages of trochanteric osteotomy. The main complication of the iatrogenic fracture is the nonunion which has occurred in about 20% of our patients (61 operations, 80% revision procedures). The rate of nonunion decreases using an optimized technique of reattachment, in particular; sufficient thickness of wires and placing of K-wires in the trochanter minor region. However, the bony nonunion has not necessarily an influence of the clinical outcome. Fibrous union provides in most cases satisfactory stability and function. In 3 patients revision surgery was necessary caused by the trochanter osteotomy: 2 suffered from a painful bursitis. In the 3rd case a strong abductor impairment occurred as the result of the trochanteric osteotomy. Refixation of the dislocated trochanter became necessary. Considering the risk of complications trochanteric osteotomy should be for exceptional cases only.
AIM: The correlation between improved cementing techniques and improved long-term results after total hip arthroplasty (THA) is well documented. The purpose of this study was to assess the use of modern cementing techniques in Germany. METHODS: A detailed questionaire regarding cement and bone preparation, cementing techniques on actabulum and femur, and implants used was sent to 584 German orthopaedic and trauma hospitals, as well as to visiting surgeons with an interest in THA. In total, 333 questionaires were available for evaluation and statistical analysis. RESULTS: In this survey, Palacos bone cement is used in 84%, low viscosity cement in 9%. Cement chilling is performed in 58%. Mixing is done by hand without vacuum mixing systems in 53%, the mixing time is standardised in 66%. For the femur 83% and for the acetabulum 74% preserve cancellous bone, 13% use pulsed lavage. Cement application is done via cement gun in 97%, in 41% in a retrograde manner and in 18% without drainage of the intramedullary canal. A cement pressurising technique is used in 63% for the femur and in 57% for the acetabulum. A cement mantle of less than 2 mm is attempted in 41%. More than 50 different stem design are implanted with the Müller straight stem being used most often, followed by anatomic designs. Almost 50% of hips are used with a 28 mm head, and almost 50% are implanted with a 32 mm head. Half the heads are ceramic, half are metal. CONCLUSIONS: The results from this survey document, that overall only slightly more than 10% of hips are implanted using second/third generation (modern) cementing techniques with application of pulsed lavage. This has implications on the number of arthroplasties that may require revision. From the data available the current status of cementing technique in Germany cannot be judged satisfactory.
The blood supply of the attachment regions of the anterior and posterior cruciate ligament is demonstrated in 14 cadaver knees by the plastination method. Our findings demonstrate the blood supply by vessels of the synovium. The direct attachment to the bone is free of vessels. Anastomoses between the synovium and the periosteum could be found. In conclusion the surgical coverage of ligament reconstruction and of ligament transplantation by synovium is recommended when ever possible to permit the ingrowth of revascularisation vessels.
Despite the great number of neoplastic entities, which are able to cause this disease, "oncogenous osteomalacia" is hardly known as a paraneoplastic phenomenon. Without removing the not constantly malignant tumor as the underlying cause recovery is not possible. Until now pathogenesis is unknown. Together with a review of the literature a case report is presented, in which a malignant fibrous histiocytoma of soft tissue caused an untreatable osteomalacia. Because of failure of local tumor control prognosis in this case must be considered fatal.
SUBJECT: We analysed the periprosthetic bone mineral density (BMD) in a prospective longitudinal study over two years after operation and in a separate cross-sectional study more than five years after implantation of cementless total hip arthroplasty (CLS-stem, Mecron threaded acetabular cup) by using dual-energy X-ray absorptiometry (DEXA). MATERIALS AND METHODS: In n = 53 patients (29 women, 24 men) we analysed the periprosthetic BMD prospectively in certain periods. All patients had an uncomplicated postoperative course and good clinical outcome (Merle d'Aubigne score > 12). In the cross-sectional study we analysed 23 patients (13 women, 10 men). Regions of Interest (ROI) were defined according to Gruen et al. for the periprosthetic femur and to De Lee and Charnley for the periprosthetic acetabulum. RESULTS: BMD significantly decreases in the periprosthetic femur as well as in the periprosthetic acetabulum during the first three months. In men BMD reaches its lowest values between six months (femur) and one year (acetabulum) after operation and then increases to 96.2% at the femur and 93.8% at the acetabulum. In women BMD decreases during the entire follow-up to 89.4% at the periprosthetic femur and 80.0% at the periprosthetic acetabulum. In the proximal zones 1 and 7 of the femur and the cranial-medial zone II of the acetabulum we observed the highest decrease of mineralisation. More than five years after implantation of the prosthesis BMD in the femur showed only little changes. On the other side BMD around the threaded acetabular cup significantly decreased to 67.4% in women and 79.1% in men. CONCLUSION: The results reflect the different stress on the periprosthetic bone after implantation of the prosthesis and fit to earlier reported good clinical results of the CLS-stem and to increased loosening rate of threaded acetabular cups after five years. Analysing changes of mineralisation in cementless total hip arthroplasty DEXA together with the analization scheme according to Gruen at the femur and to De Lee and Charnley at the acetabulum is a useful method and has been reliable in clinical practise.
The course of renal osteodystrophy possibly includes changes, which can mistakenly considered malignant. Especially dialysis-associated tumoral calcinosis may mislead to an inadequate aggressive surgical procedure. Spontaneous involution of these lesions takes place after subtotal parathyroidectomy. Brown tumors subsequent secondary hyperparathyroidism are extremely rare. During maintenance hemodialysis frequently appearing intraosseous cysts develop secondary to beta-2-microglobulin-amyloidosis. Surgery only should be performed in case of occurring pathologic fractures. Other cases are treated conservatively under continuous nephrologic supervision.
AIM: In order to establish a strategy for early diagnosis of aseptic loosening of total hip arthroplasty (THA) physical examination, patient's assessment and radiographs were analysed. METHOD: Pain, self assessment, physical examination and mobility were examined according to a standard examination protocol in 428 hips of 297 patients after cementless total hip arthroplasty (THA). These findings were compared with the radiographic finding of the hip. Sensitivity and specifity of objective and subjective parameters were analysed. RESULTS: The clinical outcome of THA's is assessed by pain and physical examination. Nearly all hip scores are based on these parameters. In this study sensitivity and specificity of all parameters analysed were unsatisfactory compared with the radiographic finding. Although we found some correlations between clinical and radiological data, clinical data alone are not sufficient for exclusion of THA loosening, especially for loosening of the acetabular component, as there was no clear distinction between the group of radiographically loosened (43 acetabular cups and 4 stems) and intact endoprostheses. CONCLUSION: We conclude, that physical examination and pain history are not sufficient to exclude loosening of cementless THA's. Radiographic examination is essential for the assessment of THA's, even in painfree patients.