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Biomedical subjects

U Bosch

Publications and source records attributed to U Bosch.

At least 19 recordsLinked to original sources
PubMed2003

Impingement pressure and tension forces of the anterior cruciate ligament.

This study examined the impingement behavior of the uninjured ACL and the impingement pressure and tension forces of the ACL to draw conclusions for ACL reconstructions. A miniature pressure sensor was inserted between the ACL and the intercondylar roof of 15 knees of human cadavers before and after a 3-mm notch roof resection (thickness of the sensor); tension of the ACL was measured after attaching the tibial insertion to a load cell. A long-arm goniometer was used to determine corresponding extension angles. The beginning of contact of the ACL with the notch roof was between -1 and -2 degrees of knee extension. Pressure for full passive extension was 855.6+/-279.1 and 346.4+/-287.7 kPa, and ACL tension averaged 101.9+/-38.4 N. Tension forces in passive hyperextension were higher than those detected when a 200-N Lachman test was performed (83.5+/-25.1 N). There was a significant correlation between extension capability and impingement pressure. Impingement of the ACL was detected in all knees. Full passive extension exerts biomechanical pressure and tension on the ACL. Tension forces of the ACL are higher in passive hyperextension than during a Lachman test with 200 N. The impingement behavior found for the uninjured ACL is simulated in an ACL reconstruction when the center tibial tunnel position is used.

Adolescent↗
PubMed2003

Comparison of human bone marrow stromal cells seeded on calcium-deficient hydroxyapatite, beta-tricalcium phosphate and demineralized bone matrix.

The aim of this study was to compare three resorbable biomaterials regarding seeding efficacy with human bone marrow stromal cells (BMSCs), cell penetration into the matrix, cell proliferation and osteogenic differentiation. Calcium-deficient hydroxyapatite (CDHA), beta-tricalcium phosphate (beta-TCP), and demineralized bone matrix (DBM) were seeded with human BMSCs and kept in human serum and osteogenic supplements for 3 weeks. Morphologic and biochemical evaluations were performed on day 1, 7, 14 and 21. The allograft DBM and CDHA exhibited both an excellent seeding efficacy while the performance of beta-TCP was lower when compared. The total protein content and the values for specific alkaline phosphatase (ALP) increased on all matrices and no significant difference was found for these two markers. BMSCs in monolayer had a significant increase of protein, but not of ALP. Osteocalcin (OC) values increased significantly higher for BMSC in cultures on DBM when compared to CDHA and beta-TCP. The OC levels decreased significantly in the BMSC monolayer culture. BMSCs were found inconsistently within the synthetic materials, whereas in DBM they were found more homogeneously distributed throughout the matrix. All three matrices promoted BMSC proliferation and differentiation to osteogenic cells. DBM allografts seem to be more favorable with respect to cell ingrowth tested by histology, and osteogenic differentiation ascertained by an increase of OC. CDHA with its high specific surface area showed more favorable properties than beta-TCP regarding reproducibility of the seeding efficacy.

Biocompatible Materials↗
PubMed2002

[Effect of cyclical stretch on matrix synthesis of human patellar tendon cells].

The significance of mobilization and loading for healing ligaments and tendons is generally accepted today. Local deformation of cells thereby represents the key stimulus for the cellular response. Less is known, however, about the effects of cyclic strain on the cellular and molecular level. The aim of the in vitro investigation was to determine the effect of cyclic mechanical strain on collagen type I and III and on fibronectin formation in human patellar tendon derived fibroblasts. Human patellar tendon derived fibroblasts from 5 donors (mean age 29.2 years) were cultured under standard conditions. Monolayers of subconfluently grown 3rd passage cells were stretched in rectangular silicone dishes with cyclic movement along their longitudinal axes. Cyclic strain (5%, 1 Hz) was applied for 30 min and 60 min, respectively. Carboxyterminal procollagen type I propeptide (P-I-CP) and aminoterminal procollagen type III propeptide (P-III-NP) release was measured by a radio-immunoassay 6 h and 12 h after stretching. The release of fibronectin was measured by nephelometry following immunoreaction with a specific antiserum. Cells from each donor without any cyclic stretching served as controls. Compared with the controls, only cyclic stretching for 60 min resulted in a significantly increased release of P-I-CP and fibronectin after 6 h. The release of P-III-NP was significantly increased 12 h after 30 min of cyclic stretching as well as 6 h and 12 h after 60 min of cyclic stretching, respectively. We conclude that cyclic stretching causes a time-dependent, differential regulation of formation of fibronectin and collagen type I and III. This may effect the quality and thus the mechanical properties of healing tendon and ligament tissues. In order to improve current treatment protocols and to enlarge our knowledge of tissue healing, it is necessary to understand the cellular response to cyclic strain.

Adult↗
PubMed2002

[Tissue engineering of tendons and ligaments. A new challenge].

Injuries to ligaments and tendons heal by formation of inferior repair tissue. This may result in severe joint dysfunction. Because of an increased occurrence of sports-related injuries, musculoskeletal disorders may become one of the major burden of health care. Tissue engineering offers the potential to improve the quality of ligament and tendon tissues during the healing process and may provide a more effective approach to the treatment of injuries to ligaments and tendons than traditional methods. Application of growth factors, gene transfer techniques, cell therapy and cell-matrix composites have shown to affect the process of ligament and tendon healing. The benefits of using mesenchymal stem cells on a three dimensional biological matrix have been shown recently. Tissue engineering will also include mechanical manipulation of tissue environments to accelerate cell differentiation and to improve matrix formation. Fibroblast-seeded polymer scaffolds could be useful in ligament and tendon replacement in which autogenous fibroblasts would be obtained through biopsy, cultured and seeded onto a scaffold.

Animals↗
PubMed2002

[Arthrofibrosis].

Arthrofibrosis represents a severe complication in joints after trauma and surgery, with loss of motion due to an excessive fibrotic response in the repair process. Patients with primary arthrofibrosis suffer from a general fibrotic healing response after injury or surgery, while patients with secondary arthrofibrosis exhibit loss of motion due to a local fibrotic healing response. Nonisometric positioning of cruciate ligament grafts, notch impingement, or hardware problems may lead to secondary arthrofibrosis. In contrast, the etiology of primary arthrofibrosis is still unknown. There are alterations of the extracellular matrix with an increase of collagen type VI expression similar to other local or systemic fibrotic disorders. A chronic inflammatory process may play a crucial role in the mechanism of primary arthrofibrosis and may indicate an immune response. It may be reasonable to assume that primary arthrofibrosis is an independent disease while secondary arthrofibrosis represents a true complication in joints resulting from trauma and surgery. Secondary arthrofibrosis can commonly be managed by arthroscopic procedures. Treatment of primary arthrofibrosis should usually include resection of dense fibrotic tissue in the anterior compartment of the knee and open posterior capsulotomy to allow full extension of the knee joint.

Connective Tissue↗
PubMed2002

[AC Joint Injuries].

There is still controversy about the treatment for acute type III acromioclavicular joint dislocation according to Tossy and Rockwood's classification. Good functional results were reported on following operative and non-operative treatment. According to the literature the functional outcome is similar. Following surgical repair, however, complications occur more often and the period of rehabilitation is longer. The disadvantages of non-operative treatment include a higher rate of a persisting prominence of the distal clavicle. Currently available data in the literature indicate that based on the criteria of evidence based medicine non-operative treatment seems to represent the method of choice for type III injuries of the acromioclavicular joint.

Evidence-Based Medicine↗
PubMed2001

[Minimally invasive screw fixation of the intracapsular femoral neck fracture in elderly patients].

INTRODUCTION: Increasing life expectancy is associated with an increase of geriatric fractures such as intracapsular femoral neck fractures. Their treatment by arthroplasty imposes a significant burden on our health care system. METHODS: In an open clinical study we investigated the complication rate of a less expensive and less invasive, femoral head saving operative procedure. Between June 1997 and June 2000, 205 intracapsular femoral neck fractures of elderly patients (mean age 78.1 +/- 11.8 years) were fixed with cannulated screws. RESULTS: Seventy-seven percent were displaced fractures and 15.6% were impacted Garden I fractures. Reoperation after internal fixation occurred in 38 patients. The most frequent cause of reoperation was secondary arthroplasty due to redisplacement (14x), femoral head necrosis (10x) and non-union (7x). Implant removal (4x), wound hematoma (1x) and femoral head penetration by screws (2x) were other causes for reoperation. CONCLUSION: Less invasive cannulated screw fixation of intracapsular femoral neck fractures should be considered as a treatment option, because it is a smaller and less expensive operation than prosthetic replacement. Adequate reduction and screw placement, however, are a prerequisite for successful outcome.

Aged↗
PubMed2001

[Acute acromioclavicular joint dislocation--operative or conservative therapy?].

42 patients with complete acromioclavicular dislocation treated operatively and 38 patients managed non-operatively were examined retrospectively with a mean follow-up of 6.3 +/- 2.5 years. The dislocations in both groups included type III and type V injuries according to the Rockwood-classification. The operative technique was suturing of the tom ligaments and stabilization of the acromioclavicular joint using resorbable coracoclavicular PDS-banding. In non-operative treatment, early physiotherapy accepting the deformity was performed in most of the patients. The clinical results using the UCLA- and the Constant-Murley score as well as evaluation of pain, function and strength were similar in both groups. Those patients suffering from a more severe dislocation type Rockwood V who were treated non-operatively had as good results as those patients with grade III dislocation. Posttraumatic osteoarthritis developed mainly in those patients whose acromioclavicular joint healed in partial dislocation. Non-operative treatment was equal even in less severe dislocations in the subgroup of type Rockwood V injuries. The persisting deformity which must be expected in non-operative treatment did not affect the patient's outcome regarding pain, function and strength of the shoulder.

Acromioclavicular Joint↗
PubMed2001

[Knee joint prosthesis implantation after fractures of the head of the tibia. Intermediate term results of a cohort analysis].

A significant number of patients with operated tibial plateau fractures develop osteoarthritis and require total knee arthroplasty. In cases of primary osteoarthritis the results are generally good. However, it is not known whether patients with post-traumatic osteoarthritis obtain comparably favorable results. In a retrospective study we analyzed 72 patients who had undergone a self-aligning (SAL) total knee arthroplasty. Ten patients received arthroplasty due to sequelae of a tibial head fracture (group I). The median time to follow-up in this group was 30 months. Clinical and radiological evaluation was based on the Knee Society Clinical Rating System. The score comprises pain, range of motion, stability, and function. We defined the axis and possible loosening by radiological examination. For comparative descriptive statistics, a cohort of patients was chosen who had received an arthroplasty because of primary gonarthrosis (group II, 76 arthroplasties in 62 patients). The median time to follow-up in this group was 46.5 months. Three patients in group I underwent revision surgery, four patients displayed severe functional deficits and pain, and one patient had a varus deformity with good clinical function. This corresponded to an early complication rate of 27% and a late complication rate of 36%; a relevant instability or loosening of the components did not occur in this group. In group II the incidence of early complications was 10%. The patients in group I reached a mean value of 153 points using the rating system vs 167 points in group II. Analyzing the clinical parameters of the score, we found that patients in group I experienced significantly more pain, thereby affecting functions of daily living, such as walking and climbing stairs. Because of the small number of patients in group I, conclusions can only be drawn to a limited extent. However, we saw that these patients displayed a higher incidence of complications and performed less well. This has to be taken into consideration and discussed prior to surgery.

Activities of Daily Living↗
PubMed2001

[Outcome analysis after open reconstruction of rotator cuff ruptures. A comparative assessment of recent evaluation procedures].

Outcome evaluation is becoming increasingly important for reconstructive surgery in musculoskeletal diseases. In addition to established shoulder-scores, new outcome-scores are being developed to cover all effects caused by a disease or intervention. Three validated, self-administered shoulder questionnaires were applied prospectively in 23 otherwise healthy patients suffering from rotator cuff deficiency. These were correlated to the Constant-Murley Shoulder Score and to a visual analogue scale for satisfaction. 7 women and 16 men with combined tears of supraspinatus and infraspinatus (mean age 55.3 +/- 10.5, r/l: 14/9, FU 57.8 +/- 15.7 weeks) were gathered prospectively and evaluated pre- and postoperatively with the American Shoulder and Elbow Surgeons Shoulder Index (ASES), the Simple Shoulder Test (SST) and the Disabilities of the Arm, Shoulder and Hand Module (DASH questionnaire). In addition, a visual analogue scale for satisfaction was employed. All four scores as well as the visual analogue scale revealed improvement at a statistically significant level (paired, two-tailed t-test, P < 0.01) after surgery. All questionnaires had a significant correlation with the Constant-Murley Shoulder Score (Pearson's correlation coefficient: ASES: r = 0.871, P < 0.01; DASH: r = -0.758, P = < 0.01; SST: r = 0.494, P < 0.05). All were easy to apply and provided a reliable, postoperative evaluation of shoulder function. The SST was easy to apply, however compound outcome analysis was only possible with the ASES Shoulder Index and the DASH questionnaire. The DASH scale was the most complex evaluation instrument. The Constant-Murley Shoulder Score comprises a physical examination which is advantageous but must be carried out in the clinic. For postoperative assessment, without the patient having to return to the clinic, the ASES Shoulder Index is preferred as it correlates well with the Constant-Murley Shoulder Score (r = 0.871) and the visual analogue scale for satisfaction (r = 0.762).

Adult↗
PubMed2001

Cyclic mechanical stretching enhances secretion of Interleukin 6 in human tendon fibroblasts.

Accelerated rehabilitation after tendon and ligament injuries is widely accepted to avoid adverse effects of immobilization. However, progressive rehabilitation may also lead to an excessive inflammatory soft tissue response. To investigate the amount of loading necessary to accelerate the healing process without causing damage to the healing tissue, we experimentally stretched human tendon fibroblasts of healthy tendons 15 and 60 min with 1 Hz and an elongation of 5% and measured the secretion of interleukin 6 (IL-6), tumor necrosis factor alpha (TNF-alpha), transforming growth factor beta1 (TGF-beta1), platelet-derived growth factor (PDGF), and fibroblast growth factor basic (bFGF). Secretion of IL-6 was significantly induced by 15 min of cyclic biaxial mechanical stretching after 4 and 8 h observation time and by 60 min stretching and 2 h observation time. The growth factors TGF-beta1, bFGF, and PDGF were secreted by human tendon fibroblasts both in stretched cells and controls; however, no increases were related to mechanical stretching. There was no measurable secretion of TNF-alpha in human tendon fibroblasts. These findings suggest that the inflammatory reaction often seen during physiotherapy after tendon and ligament injuries is caused in part by secretion of IL-6 from the stretched human tendon fibroblasts. IL-6 may cause exaggerated proliferation of fibroblasts and synovial cells as seen in rheumatoid arthritis and arthrofibrosis. However, physiological proliferative reactions leading to repair of injured tissue are also possible. IL-6 measured in the synovial fluid may be an important predictor for monitoring and improving therapeutic strategies in terms of tendon/ligament healing.

Cell Line↗
PubMed2001

Arthrofibrosis is the result of a T cell mediated immune response.

It is thought that an excessive fibrotic healing response with diffuse intra-articular scarring leads to arthrofibrosis after trauma and surgery around joints. To clarify the specific cellular mechanism of arthrofibrosis during arthrolysis we took fibrotic tissue samples from 18 patients at varying periods after knee trauma or surgery. Sections were stained with hematoxylin and eosin to study the overall histopathological changes. Major histocompatibility complex (MHC) class II expressing cells as well as CD3, CD4, CD25, CD28, CD68, CD80, and CD83 positive cells were localized immunohistologically. The results demonstrated synovial hyperplasia with fibrotic enlargement of the subintima and infiltration of inflammatory cells. The number of MHC class II expressing cells was increased. Mainly, intimal macrophages and dendritic cells showed positive immunostaining for MHC class II antigens. In the subintima moderate infiltration of T cells including activated T cells (CD25), CD4+ T helper (Th) cells and Th1 and Th2 subsets was detected. There was a slight polarization of the Th1/Th2 balance towards Th1 differentiation. Positive immunostaining for CD80/CD28 indicated the costimulatory signal for T cell activation and clonal expansion. These findings strongly support an immune response as the cause of capsulitis leading to formation of diffuse scar tissue within the knee joint. Based on our immunohistological study we conclude that a T cell mediated immune response plays a crucial role in the mechanism of arthrofibrosis.

Adolescent↗
PubMed2001

Cyclic mechanical stretching modulates secretion pattern of growth factors in human tendon fibroblasts.

The objective of the study was to investigate whether the response profile of the growth factor of human tendon fibroblasts could be beneficially influenced through the application of mechanical stretch. It was considered that this would elucidate structural and functional problems, often seen after tendon and ligament healing. The secretion pattern of transforming growth factor-beta (TGF-beta), platelet-derived growth factor (PDGF) and basic fibroblast growth factor (bFGF) was determined in mechanically stretched fibroblasts and compared to non-stretched controls. Human tendon fibroblasts were experimentally stretched for 15 and 60 mm at a frequency of 1 Hz and an amplitude of 5%. The secretion of TGF-beta PDGF and bFGF was measured by enzyme-linked immuno-sorbent assay. All the growth factors investigated were indeed secreted by human tendon fibroblasts both in stretched cells and controls. Mechanical stretch increased the secretion pattern of the growth factors. The increased concentrations of TGF-beta bFGF and PDGF after cyclical mechanical stretching may have a positive influence on tendon and ligament healing through stimulation of cell proliferation, differentiation and matrix formation.

Adult↗
PubMed2001

[Bone screw osteosynthesis of medial femoral neck fracture in elderly patients].

This study evaluated the complication rate and surgical outcome following cannulated screw fixation of femoral neck fractures in elderly patients. Between 1.6.97 and 31.12.98 we operated on 110 patients with 112 fractures. The mean age was 78.4 years (range 25-96 years). Mean follow up was 6.8 months (range 3-16 months). The mortality rate was 22.7% (25/110). 60 patients with 61 fractures could be evaluated for complications, reoperations, pain and walking ability. 68.9% of the fractures healed. Avascular necrosis developed in 18%. Non-union rate was 8.2% and redislocation rate 4.9%. 18 patients needed a second operation, two thirds received an arthroplasty and one third had implant removal or replacement. In 81.6% of the patients (the patients with secondary arthroplasty excluded) pain relief was good. Insufficient reduction and malposition of the screws are the most common causes for failure of cannulated screw fixation of femoral neck fractures in the elderly.

Adult↗
PubMed2001

Proprioception in anterior cruciate ligament reconstruction. Endoscopic versus open two-tunnel technique. A prospective study.

ACL-reconstruction with patellar tendon autograft is a standard procedure which can be performed arthroscopically with a femoral half tunnel drilled from the joint or using the two-tunnel technique with medial miniarthrotomy and additional femoral approach. The arthroscopic procedure with single incision was hypothesized to improve proprioception and to provide earlier rehabilitation. Twenty-nine patients with chronic ACL-deficiency were included in the prospective study. Fifteen patients were operated endoscopically, 14 patients using the two-tunnel technique. Proprioception, Lysholm and Tegner scores as well as stability (KT-1000) were assessed preoperatively, 3 and 6 months postoperatively as well as after 3.9 +/- 0.4 years. A significant deficit of proprioception was assessed in both groups preoperatively. Six months postoperatively, both groups showed a restitution of proprioception near full extension and full flexion of the knee. In the mid-range position, the proprioception could not be restored. At the final examination after 3.9 years, the deficit documented in the mid-range position still persisted. There were no differences in proprioception, clinical results and stability between the arthroscopic and the open technique.

Adult↗