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A Gächter

Publications and source records attributed to A Gächter.

At least 19 recordsLinked to original sources
PubMed2000

Endurance sports after total knee replacement: a biomechanical investigation.

PURPOSE: No biomechanical evaluation of total knee designs exists for loads occurring during sports activities. It was the purpose of the present study to evaluate the contact stress distribution and contact area of different knee joint designs for loads that occur during four common recreational endurance activities. METHODS: Three different total knee designs were evaluated for loads occurring during cycling (1.2 body weight (BW) at 80 degrees of knee flexion), power walking (4 BW at 20 degrees), hiking (8 BW at 40 degrees), and jogging (9 BW at 50 degrees) using Fuji pressure-sensitive film. The designs consisted of a flat tibial inlay, a curved inlay, and an inlay with mobile bearings. Five measurements were conducted for each load. The pressure sensitive films were scanned and analyzed using an image analysis program. RESULTS: During cycling, the area with stress levels above the yield point of polyethylene (overloaded area) was below 15 mm2 for each design. During power walking, the mobile bearing design showed no overloaded area, whereas it was below 50 mm2 for the flat and curved design. During downhill walking and jogging, more than 140 mm2 were overloaded for each design. CONCLUSIONS: It was concluded that patients after total knee replacement should alternate activities such as power walking and cycling. For mountain hiking, patients are advised to avoid descents or at least use ski poles. Jogging or sports involving running should be discouraged after total knee replacement.

Biomechanical Phenomena↗
PubMed2000

Arthroscopic findings in acute fractures of the ankle.

We have evaluated prospectively the arthroscopic findings in acute fractures of the ankle in 288 consecutive patients (148 men and 140 women) with a mean age of 45.6 years. According to the AO-Danis-Weber classification there were 14 type-A fractures, 198 type B and 76 type C. Lesions of the cartilage were found in 228 ankles (79.2%), more often on the talus (69.4%) than on the distal tibia (45.8%), the fibula (45.1%), or the medial malleolus (41.3%). There were more lesions in men than in women and in general they were more severe in men (p < 0.05). They also tended to be worse in patients under 30 years and in those over 60 years of age. The frequency and severity of the lesions increased from type-B to type-C fractures (p < 0.05). Within each type of fracture the lesions increased from subgroups 1 to 3 (p < 0.05). The anterior tibiofibular ligament was injured with increased frequency from type-B.1 to type-C3 fractures (p < 0.05), but it was not torn in all cases. While lateral ligamentous injuries were seen more often in type-B than in type-C fractures (p < 0.05), no difference was noted in the frequency of deltoid ligamentous lesions. Our findings show that arthroscopy is useful in identifying associated intra-articular lesions in acute fractures of the ankle.

Acute Disease↗
PubMed1999

The benefits of wearing a compression sleeve after ACL reconstruction.

PURPOSE: It was the purpose of the present study to examine the possibility of increased muscle coordination after anterior cruciate ligament (ACL) reconstruction through the wearing of a compression sleeve. METHODS: Thirty-six patients were studied who had undergone unilateral ACL reconstruction at least 12 months previously. All subjects were required to perform a 10-cm standing drop jump from an elevated platform onto a force plate, to land on one leg, and thereafter maintain a one-legged balance for 25 s. This task was repeated three times without and three times with an elastic compression sleeve worn on the reconstructed limb. For analysis, the task was partitioned into a landing phase (150 ms), an adjusting phase (10s), and a balancing phase (10s). The peak impact loadings were measured in each direction (Fx, Fy, and Fz) during landing, while force-time integrals (intFz, intFy, and intFz) and root mean square (RMS) error of these forces were calculated for the adjusting and balancing phases. The path length and RMS of the center of pressure coordinates (Ax and Ay) were obtained for the adjusting and balancing phases combined. RESULTS: Drop landings with the bandage produced significantly larger (P < 0.001) peak ground reaction forces in the vertical and anteroposterior direction, suggesting increased subject confidence in their knee. Wearing the knee bandage also enabled the patients to reduce all measured parameters in the anteroposterior direction (rmsFx, intFx, rmsAx) during both the adjusting and balancing phases (P < 0.001 ). A significant reduction in the center of pressure path length further indicated an enhanced steadiness during the one-legged stance. CONCLUSIONS: It was concluded that a compression sleeve improved the total integration of the balance control system and muscle coordination.

Adult↗
PubMed1998

Modulation of alloimmune response in vitro by an IgM-enriched immunoglobulin preparation (Pentaglobin).

The mode of action of intravenous immunoglobulins (IVIG) in autoimmune and immunoregulatory disorders is still poorly understood. In vitro, direct effects of IVIG on cytokine release and on cytokine receptors have been described, as well as naturally occurring, neutralizing anticytokine antibodies. The aim of our study was to investigate whether the enrichment in IgM and IgA would have any impact on the in vitro immunomodilatory capacity of IVIG. The preparation tested (Pentaglobin) contains 76% IgG and 12% IgM and IgA, respectively. We could demonstrate a significant inhibition of alloantigen-induced proliferation in the mixed lymphocyte reaction (MLR) even at a Pentaglobin concentration of 1.0 mg/ml. About 10-fold higher concentrations of standard 7S IVIG containing only trace amounts of IgM and IgA were necessary to achieve equivalent suppression of the alloimmune response. Similarly, phytohaemagglutinin (PHA)-induced lymphocyte proliferation was more effectively inhibited by Pentaglobin than by standard 7S IVIG. Cytokine analyses in culture supernatants of MLR provide evidence that Pentaglobin not only modulates interleukin-2 (IL-2), which has already been observed with standard 7S IVIG, but, moreover, modulates interferon-gamma production with a subsequent impact on monocyte-derived tumour necrosis factor-alpha and IL-6 release. Based on these results we conclude that in vitro the IgM- and IgA-enriched Pentaglobin has a more potent immunomodulatory capacity than conventionally used standard 7S IVIG.

Cell Culture Techniques↗
PubMed1998

[The first dislocation of the shoulder].

The classical anterior-inferior dislocation of the shoulder is diagnosed easily by clinical examination and x-ray. The additional lesions like impression fracture at the humerus, avulsion of the anterior rim of the glenoid, lesions of the rotator cuff or neurologic deficits are more difficult to realise. In young patients the redislocation rate is rather high. Indication for surgery is still on debate. Modern diagnostic tools will help to determine additional lesions. More problems are incountered in presence of a posterior dislocation. Those are often overlooked.

Arthroscopy↗
PubMed1998

[Knee dislocation].

Dislocations of the knee represent a rare but serious injury with an impaired prognosis. The optimal treatment still remains an object of discussion. Within seven years eleven patients have been treated in our hospital after this injury. The review of their reports showed a high incidence of neurovascular damage, loss of motion as well as stiffness. The outcome of the patients with operative treatment was superior to that of the patients with a nonoperative approach. Based on our own results and on the experiences of other authors we present our recommendations in the management of knee dislocations.

Adolescent↗
PubMed1997

Dendritic cells generated from blood precursors of chronic myelogenous leukemia patients carry the Philadelphia translocation and can induce a CML-specific primary cytotoxic T-cell response.

Dendritic cells (DC) are professional antigen-presenting cells specialized in the initiation of primary immune responses. We were interested to know whether mature DC can be grown in vitro from peripheral blood mononuclear cells (PBMC) of patients with chronic myelogenous leukemia (CML), and whether they carry the Philadelphia (Ph) translocation. Using a method recently described, DC were generated from PBMC precursors of 12 patients with CML using GM-CSF, IL-4, and monocyte-conditioned medium. DC exhibited the typical morphology with thin cytoplasmatic processes and expressed high levels of MHC class II, CD86, and CD83 typical for mature DC. After sorting with the monoclonal antibody CD83, a cell population of more than 95% CD83 positive cells was obtained. The presence of the Ph translocation was analyzed in these cells, in PBMC, lymphoblastoid cell lines (LCL), and in phytohemagglutinin (PHA)-induced T blasts from the same patients by fluorescence in situ hybridization (FISH). In contrast to all other cells analyzed, the vast majority of DC (95.9 +/- 0.7%) displayed the Ph translocation, irrespective of disease stage or therapy. PBMC were predominantly positive for the Ph chromosome (67.6 +/- 7.3%), whereas only 11.4 +/- 1% of the B cells and 4.4 +/- 1.1% of the PHA blasts carried the Ph translocation. Using such leukemic DC as antigen-presenting cells, a primary CML-directed cytotoxic immune response in vitro was obtained, as shown by the specific recognition of Ph chromosome positive cells. We conclude that DC can be generated from blood progenitors of CML patients in vitro and exhibit, to a large extent, the Ph translocation. Such DC, which in a preliminary experiment have been able to induce a primary CML-directed cytotoxic immune response in vitro, might be ideal candidates for adoptive immunotherapy either by direct transfer of DC for in vivo generation of a T-cell response or by in vitro generation of CML-specific cytotoxic autologous or HLA-matched normal T-cell clones for use in vivo.

Cell Line, Transformed↗
PubMed1997

Diagnostic validity of ultrasound in patients with persistent wrist pain and suspected occult ganglion.

Until recently, the presence of occult ganglions could be determined only by surgical exploration. This prospective study investigated the reliability of ultrasound in the diagnosis of occult ganglions in a patient series over 4 years. The sensitivity, specificity, and accuracy of ultrasound, as well as its positive and negative predictive values, were determined in 83 patients suspected of having an occult wrist ganglion and who had persistent pain and consented to an operation. Examinations were carried out with a 7.5-MHz linear probe and spacer. Outcome of surgery and histologic examination served as the gold standard in 168 patients who had undergone ultrasound; 89 underwent surgery. In 83 patients for whom enough information was available to allow statistical assessment, sensitivity, specificity, and accuracy rates of 88%, 85%, and 87% were respectively obtained. In dorsal wrist ganglions (75%), better results were obtained: a sensitivity rate of 93%, a specificity rate of 86%, and an accuracy rate of 91%. It was concluded that ultrasound of the wrist can be used as a first-line imaging procedure in clinically inconclusive situations and that ultrasound evidence of an occult dorsal ganglion is a reliable indicator for surgery.

Adult↗
PubMed1997

CD34+-selected autologous peripheral blood stem cell transplantation (PBSCT) in patients with poor-risk hematological malignancies and solid tumors. A single-centre experience.

Between July 1994 and December 1996, PBSC were mobilized in 28 patients with poor-risk hematological malignancies and solid tumors. CD34+ cells were positively immunoselected using the Ceprate CS System. By December 1996, 22 patients had been reinfused with a median of 3.325 (0.078-9.5) x 10(6)/kg CD34+ cells. In three patients unselected back-up PBSC had to be transfused along with selected CD34+ cells because of a CD34+ cell number <0.5 x 10(6)/kg. G-CSF (10 microg/kg) was started on day +1 and all patients engrafted within a median day number of 12 (range, 10-22) until leukocytes >1.0 x 10(9)/l and a median day number of 56 (range, 10-180) until platelets >20.0 x 10(9)/l (ie platelet transfusion independence). Time to leukocyte and platelet recovery was significantly shorter in patients receiving >2.0 x 10(6)/kg purified CD34+ cells as compared to patients reinfused with <2.0 x 10(6)/kg CD34+ cells. The hematopoietic recovery time was similar to that of 18 historical control patients treated with unseparated ABMT +/- PBSCT with the exception of a significantly faster leukocyte engraftment in patients receiving >2.0 x 10(6)/kg CD34+ cells and a significantly delayed platelet recovery time in patients receiving <2.0 x 10(6)/kg purified CD34+ cells. There was a trend for a better overall survival and a lower probability of progression/relapse as compared to the historical controls. We observed five episodes of serious opportunistic infections (three pulmonary fungal infections, two cases of cryptosporidiosis) after the take. Four of these patients had been reinfused with <2.0 x 10(6)/kg CD34+ cells probably indicating a delayed immune reconstitution after CD34+-selected PBSCT.

Antigens, CD34↗
PubMed1997

A comparative study of the in vitro immunomodulatory activity of human intact immunoglobulin (7S IVIG), F(ab')2 fragments (5S IVIG) and Fc fragments. Evidence for post-transcriptional IL-2 modulation.

During the past few decades intravenous immunoglobulin (IVIG) has been used successfully in the treatment of various immunoregulatory disorders. Treatment results have been attributed to immunomodulation mainly via Fc receptors or by anti-idiotypic antibodies to disease-causing autoantibodies. From the present study it is clearly evident that 7S IVIG (intact immunoglobulin) as well as 5S IVIG [F(ab')2 fragments] and Fc fragments have a potent immunomodulatory capacity. We demonstrate that mainly 7S IVIG inhibits alloantigen-induced T-cell proliferation and generation of cytotoxic T lymphocytes. Reduced interleukin-2 (IL-2) protein levels in culture supernatants of IVIG-supplemented mixed lymphocyte reactions (MLR) but unchanged IL-2 mRNA levels strongly argue in favour of a post-transcriptional interference of IVIG with cytokines and/or cytokine production. Interferon-gamma (IFN-gamma), soluble IL-2 receptor (sIL-2R) and monokines such as IL-1 beta, IL-6, IFN-alpha and tumour necrosis factor (TNF-alpha) were not affected by IVIG supplementation to MLR. Fc fragments were superior to F(ab')2-containing IVIG (5S and 7S IVIG) in inhibiting lectin stimulation of peripheral blood mononuclear cells (PBMC), whereas natural killer (NK) cytotoxicity was primarily inhibited by Fc-bearing IVIG (7S IVIG and Fc fragments), suggesting multiple mechanisms of IVIG immunomodulatory activity.

Antigen Presentation↗
PubMed1997

Joint load considerations in total knee replacement.

Estimates of knee joint loadings were calculated for 12 normal subjects from kinematic and kinetic measures obtained during both level and downhill walking. The maximum tibiofemoral compressive force reached an average load of 3.9 times body-weight (BW) for level walking and 8 times BW for downhill walking, in each instance during the early stance phase. Muscle forces contributed 80% of the maximum bone-on-bone force during downhill walking and 70% during level walking whereas the ground reaction forces contributed only 20% and 30% respectively. Most total knee designs provide a tibiofemoral contact area of 100 to 300 mm2. The yield point of these polyethylene inlays will therefore be exceeded with each step during downhill walking. Future evaluation of total knee designs should be based on a tibiofemoral joint load of 3.5 times BW at 20 degrees knee flexion, 8 times BW at 40 degrees and 6 times BW at 60 degrees.

Adult↗
PubMed1996

Evidence for a graft-versus-tumor effect in a patient treated with marrow ablative chemotherapy and allogeneic bone marrow transplantation for breast cancer.

Graft-versus-leukemia (GvL) has been shown to be an important immune-mediated antitumor effect in hematologic malignancies. It is still unknown whether such an immunemediated antitumor effect has clinical implications in patients with solid tumors. A 32-year-old woman with inflammatory breast cancer received a bone marrow transplant (BMT) from her HLA-identical sibling. During graft-versus-host disease (GvHD) cytotoxic T lymphocytes were grown and tested in a chromium-release assay against B and T lymphocytes of the patient and donor and against a panel of breast cancer cell lines. Resolution of liver metastases was observed simultaneously with clinical GvHD in the first weeks after transplant. In addition, minor histocompatibility antigen (MiHA)-specific and major histocompatibility complex (MHC) class I antigen-restricted cytotoxic T lymphocytes recognizing breast carcinoma target cells were isolated from the blood of the patient. Pretreatment of such target cells with tumor necrosis factor (TNF)-alpha but not with interferon (IFN)-alpha or IFN-gamma increased susceptibility of these cells to lysis by cytotoxic T lymphocytes. Clinical course and in vitro results suggest that a graft-versus-tumor (GvT) effect might exist after allogeneic BMT for breast cancer. However, clinical experience on a larger scale would be required to determine the clinical efficacy of GvT effects in patients with solid tumors.

Adult↗
PubMed1996

Comparison of augmented and non-augmented anterior cruciate ligament reconstruction combined with high tibial osteotomy.

In a follow-up study 27 patients were evaluated after anterior cruciate ligament (ACL-)reconstruction combined with high tibial osteotomy because of chronic rupture of the ACL, cartilaginous lesions of the medial compartment and varus malalignment. They were divided into two groups. In 14 patients (non-LAD group) ACL reconstruction was performed using the central third of the autologous patellar tendon modified according to Eriksson-Trillat. Thirteen patients (LAD group) underwent repair with the same technique, but a Kennedy ligament augmentation device (LAD) in "hot dog' technique and fixed over the top was added. The postoperative treatment was the same in both groups. All patients were examined according to IKDC criteria. KT-1000 arthrometer testing at maximum manual traction was performed. Although the mean follow-up interval was more than double in the non-LAD group (non-LAD: 127 months vs LAD: 58 months), the subjective and clinical results, IKDC evaluation and KT-1000 arthrometer testing results were similar, showing no statistically significant difference. Further, no complications due to the use of LAD occurred. In this study no evident functional or clinical advantage from the augmentation performed could be shown.

Activities of Daily Living↗
PubMed1996

The first metatarsal rise sign: a simple, sensitive sign of tibialis posterior tendon dysfunction.

Although foot deformation starts in the early stage of tibialis posterior (TP) tendon dysfunction, this condition is often overlooked or misdiagnosed. We observed consistently a clinical sign of TP tendon dysfunction that, to our knowledge, has not yet been described. Patients were tested while they were standing and fully weight-bearing with both feet. When the shank of the affected foot was taken with one hand and externally rotated, or when the heel of the affected foot was taken with one hand and brought passively into a varus position, the head of the first metatarsal raised in the case of TP dysfunction and remained on the ground in normal TP function. The purpose of this prospective study was to validate this clinical finding by surgical exploration, and to compare its sensitivity with other common clinical signs. Our series included 21 consecutive feet with TP tendon dysfunction (19 patients). The deformity was supple in 12 feet and fixed in 9 feet. Radiographs and magnetic resonance imaging were found to be unreliable in diagnosing dysfunction of the TP tendon. While other clinical signs (too many toes, the single-heel rise, and the double-heel rise) were noted to be negative in 20% to 35%, we found our first metatarsal rise sign to be positive in all cases of TP tendon dysfunction. This simple clinical test enables us to recognize and treat a dysfunction of the TP tendon at an early stage, when the foot is still supple. As the foot deformation progresses, early treatment may be the most effective measure in preventing long-term functional impairment.

Adolescent↗
PubMed1995

Anterior cruciate ligament reconstruction combined with valgus tibial osteotomy (combined procedure).

We assessed the patients who were operated on in a combined procedure from 1980 to 1992 with anterior cruciate ligament (ACL) insufficiency, cartilaginous lesions of the medial compartment, lesion of medial meniscus and varus malalignment. The combined operative procedure was autologous intra-articular ACL reconstruction with the middle third of the patellar ligament--partially augmented with Kennedy-ligament augmentation device (LAD) in hot dog technique--and high tibial osteotomy. The patients were examined according to the criteria of IKDC including testing of anterior stability with the KT-1000 arthrometer. Radiographically we checked axis and arthritis according to a modified score of Kannus. Twenty-seven of 34 patients who fulfilled the inclusion criteria could be followed up in three categories (2-5 years post-operatively, 5-10 years postoperatively, over 10 years post-operatively). Total qualification was good in 37%; there were no perioperative complications. Rehabilitation was not prolonged. Eighty-nine percent practised their preoperative job, over 50% had a higher level of sports activities than preoperatively, and more than 25% regained their pretraumatic sports capacity. Two-thirds had no giving way and less than 3 mm translation difference in comparison to the contralateral knee. Seventy-five percent of patients would accept the operation again. Radiological findings had no correlation to overall qualification. The encouraging results with respect to many of the criteria suggest using the combined procedure in a young patient with ACL insufficiency, varus malalignment and medial compartment damage including medial meniscus lesion.

Adult↗
PubMed1995

Spin-echo and 3D gradient-echo imaging of the knee joint: a clinical and histopathological comparison.

OBJECTIVE: A clinical and histopathological comparison of 2D spin-echo (SE) and 3D gradient-echo (3DGE) sequences was undertaken for the knee joint. The purpose of the study was to evaluate the clinical results and to explain the different appearances of meniscal abnormalities on both 2DSE and 3DGE images. PATIENTS, MATERIALS AND METHODS: The clinical study comprised 45 patients with arthroscopically correlated MR imaging results. For the histopathological correlation, seven cadaveric knee joints were examined with the same 2DSE and 3DGE (FISP) imaging protocol and sliced in sagittal sections according to the MR images. Different stainings were used. RESULTS: For the detection of meniscal tears, accuracy (82.2%) and positive predictive value (70.7%) of the 3DGE sequence were limited due to a high number of false positive findings. Cartilaginous lesions were more easily visible on 3DGE than on 2DSE images (sensitivity: 63.1% vs. 52.6%, respectively). As in the clinical study, the meniscal signal abnormalities of the cadaveric knee joints were much more extensive on the 3DGE images than on the 2DSE images. The 3DGE findings correlated better with degenerative meniscal changes which were visible microscopically. CONCLUSION: The high sensitivity of the 3DGE sequence for degenerative meniscal changes explains the lack of specificity for the differentiation between meniscal degeneration and tears with this sequence. The MR grading system for meniscal lesions is of limited value for the evaluation of 3D FISP images.

Adult↗