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Biomedical subjects

M Stárek

Publications and source records attributed to M Stárek.

At least 19 recordsLinked to original sources
PubMed2006

[Z-plasty for valgus deformity in total knee arthroplasty].

PURPOSE OF THE STUDY: Several options for treatment of valgus deformity in total knee arthroplasty (TKA) have been described. In 2002 the lateral approach to the valgus knee with Z-plasty of the articular capsule involving part of Hoffa's fat pad started to be used in our department. In this study the surgical technique, including steps for gradual deformity correction, is described and shortterm results are evaluated. MATERIAL: A total of 1136 TKAs were carried out in the period from 1994 to 2004; of these 131 (11 %) were performed on valgus knee. After a visit to the Schulthess Klinik and personal communication with Dr. med. T. Drobny, we began to use the lateral approach to the valgus knee, with Z-plasty of the articular capsule and involvement of Hoffa's fat pad. Forty-two patients (35 women and 7 men) were treated by this technique. The average age of this group was 71 years, and the average preoperative valgus deformity was 20.5 degrees. METHODS SURGICAL TECHNIQUE: A skin incision is made along the midline and, in its lower part, it is led toward the lateral border of the tibial tubercle. The joint capsule is incised in the superficial layer at about 2 cm lateral to the patella. Dissection of the superficial and deep layers of the capsule is made laterally, extending up to 4 cm. After joint exposure, the fat pad is separated from the medial attachment and preserved, on a lateral pedicle, with the patellar ligament. If needed, this flap can be used to close a defect in the distal articular capsule. By including both parts of the joint capsule produced by Z-plasty, medial transposition of the patella is achieved after suture. The deformity is corrected in a sequential manner according to its severity and the effect of release in each step, as follows: 1) Point incisions of the iliotibial band at a 5-cm distance above the articular fissure (piecrusting). 2) Subperiosteal elevation of the iliotibial band attachment from Gerdy's tubercle. 3) Release of the posterolateral capsule. 4) Subperiosteal release of the femoral attachment of the lateral collaterall ligament and dissection of the popliteal muscle. 5) Release of the lateral head of the gastrocnemius muscle. The evaluation of patients was based on the Knee Society Clinical Rating System. RESULTS: Using this surgical technique, correction of deformity was achieved in all patients. The knee axis after surgery improved to 6.6 degrees on the average. The more extensive dissection of lateral structures resulted in larger blood losses, which were on average 1150 ml, and the procedure also required a longer tourniquet application (55 min). The patients were followed up on average for 22 months. The Knee Score assessment in the whole group (42 knees) was on average 90.6 points, with 92.0, 93.3 and 87.9 for rating system categories A, B and C, respectively. The average range of motion was 0 to 118 degrees , and none of the patients reported femoropatellar problems. Revision surgery for hematoma was performed in one patient and puncture of the knee joint had to be done in several patients. Redress for postoperative motion restriction was carried out in three patients and one patient underwent repeat surgery for infection. DISCUSSION: The lateral approach with Z-plasty of the capsule and fat pad involvement provides maximal release of and access to the lateral structures, reduces the risk of insufficient blood supply of the patella and also resolves patellar subluxation. This technique thus allows us to reduce the probability of developing femoropatellar problems that are frequently responsible for poor TKA outcomes in the valgus knee. CONCLUSIONS: The technique described here is an effective approach to the valgus knee requiring total replacement. It provides good access to exposed lateral structures and, with the use of Z-plasty, permits correct alignment and tracking of the patella. In addition, it minimally interferes with blood supply to the patella and completely avoids problems associated with suture of the articular capsule.

Aged↗
PubMed2005

[Our experience with revision total knee arthroplasty].

PURPOSE OF THE STUDY: In the period from 1990 and June 2003, 885 total knee replacements were performed at the orthopedic ward of the Ceske Budejovice Hospital. Of these, 19 (2.14 %) patients underwent revision surgery; in addition, 25 patients who had had primary surgery in other hospitals were operated on. Of these 44 patients, 25 were followed up and evaluated. The aim of the study was to evaluate the pre-operative treatment including examination for bacterial infection by cultivation, the selection of an optimal procedure (one- or two-stage operation, surgical approach and implantation technique) and postoperative therapy. MATERIAL: The 25 evaluated patients were followed up for an average of 34.5 months (range, 6-109 months) after reimplantation. Loosening occurred in most of the commonly used types of primary implants. The group comprised five men and 19 women; the average age at the time of reoperation was 70 years (range, 51-78 years). Ten patients had repeat surgery on the left and 14 on the right knee at an average of 43.5 months (range, 4-120 months) after primary surgery. Fourteen patients were treated by one-stage and 10 patients by two-stage surgery. The Genesis system (Smith Nephew) was used in 13 patients, Sigma PFC revision implant (Johnson and Johnson) in eight, Walter-Motorlet implant (reuse of the primary implant at the time when a revision system was not available) in one and external fixator in five patients. METHODS: Revision arthroplasty was indicated on the basis of clinical symptoms and X-ray, scintigraphic and biochemical (CRP, WBC, FW) examinations. The use of recently adopted methods (procalcitonin, orosomucoid, alpha-1-antitrypsin, beta-2- macroglobulin, ceruloplasmin, PCR and PET) was not evaluated because of short-term applications. Patients in whom infection or colonization of the implant was suspected were treated by two-stage reimplantation, using a canalized spacer with a stem and a patellar pelota made of antibiotic-loaded cement. The average time between implant removal and reimplantation was 108 days (range, 60-244 days). Each removed implant was placed in a culture medium for 5 to 7 days. This resulted in a high occurrence of positive cultivation results even in the patients who, on the basis of previous examination, were first considered to have had aseptic loosening and had undergone one-stage surgery. All patients with positive tests received long-term antibiotic therapy, usually a combination of ciprofloxacin and rifampicin, according to the cultivation results. RESULTS: Out of 14 one-stage reimplantations (indicated for by the negative results of all laboratory examinations), implant colonization was recorded in five cases, with a coagulase-negative staphylococcus being the most frequent infectious agent. No recurrent infection was found after the long-term antibiotic course. One patient with the implant infected with Staphylococcus aureus underwent primary arthrodesis. Out of 10 two-stage reimplantations (in patients with positive laboratory tests), recurrent infection was found in two cases and was caused by a pathogen different from the original one. The patients were treated by arthrodesis. Good outcomes, defined as a functional total knee replacement free from infection at least 6 months after reimplantation, were achieved in 79 % of the patients. Better functional results were obtained by onestage surgery. Patients with concomitant rheumatoid arthritis had aseptic loosening more frequently, and patients with impaired immunological status, due to diabetes mellitus, cytostatic drug or corticosteroid administration, more often showed septic loosening. DISCUSSION: The 2.14 % loosening of total knee arthroplasty in our patients (19 out of 885) can be considered a good result. A functional joint was achieved in all patients (100 %) with aseptic loosening and in 69 % of those with infected or colonized implants. The results of routine biochemical tests and bacteriological cultivation did not allow us to distinguish aseptic from septic loosening with certainty. Therefore, we adopted new screening markers (PCR and PET) and a new method of microbiological examination of the removed implant and collected tissue. However, we could evaluate the role of these specialized tests only on the basis of literature data, since we had only short-term experience with them ourselves. Our results with the treatment of early loosening of total knee arthroplasty suggest that patients benefit more from the two-stage procedure. CONCLUSIONS: We strongly emphasize the employment of all possible means to prevent loosening, i. e., to use an appropriate surgical technique for primary implantation, to observe aseptic principles and to administer antibiotic therapy in conditions suspected of bacteremia. The shorter the interval between the onset of complaints and the reimplantation, the better results. Early loosening should be treated by two-stage surgery. Our method of bacteriological examination gives good results. Because of complexity of the problem, patients with a loose knee prosthesis should be referred to orthopedic departments with experienced and skilled surgical teams and high-quality examination facilities.With the observation of appropriate procedures, there is a great chance of achieving good results. Arthrodesis is still regarded as a justified "salvage" operation, particularly in cases with pre-operative findings of Staphylococcus aureus. Procedures for repeat surgery following the failure of a reimplanted joint have so far yielded doubtful results and still await further development.

Aged↗
PubMed2004

[Total knee arthroplasty with the Beznoska S.V.L. implant: short-term results].

PURPOSE OF THE STUDY: To present and evaluate short-term clinical results of total knee arthroplasty using the Beznoska S. V. L. implant and to compare them with the results of other authors. MATERIAL: In the period from April 1997 to October 2002, 197 total knee replacements with a S. V. L. implant were carried out of these, 164 implants were evaluated in 146 patients. This group comprised 116 women (78 %) and 48 men (22 %), with an average age of 73.6 years (range, 63 to 83) at the time of surgery. The patients were evaluated on average at 4.3 years (range, 1.5 to 6.5) after surgery. Indications for replacement were primary knee arthritis in 151, rheumatoid arthritis in nine, secondary post-traumatic arthritis in two and conditions following tibial osteotomy in two cases. METHODS: The results were evaluated using the Knee Society Clinical Rating System which consists of three parts: Knee Score (100 points), Knee Function Score (100 points) and Categorical Score (allocating patients to three groups according to function deficiencies of other joints). X-ray images were examined for implant position, the presence of radiolucent lines and patellar position, and assessed on the basis of the Knee Society Total Knee Arthroplasty Roentgenographic and Scoring System. RESULTS: No or mild pain in the treated joint was reported by 90.2 % of the patients. Severe pain was not recorded at all. The average maximal range of flexion increased from 94 degrees preoperatively to 104 degrees post-operatively. The range of motion more than 90 degrees and that of more than 100 degrees were recorded in 96 % and 76.8 % of the operated-on knees, respectively. An anteroposterior mild instability of 5 to 10 mm was objectively found in nine knees (5.5 %) a medial laxity of 6 to 9 degrees was detected in 36 knees (22 %) and that of 10 to 15 degrees only in one patient. Severe instability was not recorded. The leg axis achieved after surgery was on average 6.4 degrees valgus, compared to 5.5 degrees varus before surgery. The total Knee Score was 85.1 points (range, 53 to 100), with excellent or good outcomes in 151 knee replacements (92 %). Six patients (4.6 %) reported failure to walk a distance of more than 500 m on an even terrain, six (4.6 %) could not manage the stairs and five (3 %) required a permanent use of two crutches or a walking frame. The average function score, which also included the effect of concomitant diseases of other joints, was 64.9 points (range, 40 to 100), with excellent or very good outcomes being achieved in 64 implants (39 %). On X-ray examination of implant position in anteroposterior projection, the average valgus angle of the femoral component was 94.8 degrees (range, 92 to 100) and the tibial angle was 90.3 degrees (range, 85 to 94). In lateral projection the flexion angle of the femoral component was 2.5 degrees (-1 to 6) and the average dorsal tilt of the tibia was 3 degrees. Distinct radiolucent lines up to 1 mm in width were seen in the femoral component in 10 (6 %) cases and in the tibial component in 27 (16.5 %) cases, this occurred in zones 1, 2 or 4. Wider lines of 2 mm were present in both components in 6 (3 %) cases. Radiolucent lines were recorded in 43 (26 %) implants. The patella examined in axial projection was correctly centered in 140 (85 %) total knee replacements. Eleven patients reported femoropatellar problems and, in three of them, patella replacement was subsequently performed. No aseptic loosening occurred and one deep infection (0.6 %) was treated by a two-stage reimplantation. DISCUSSION: Excellent to very good outcomes, with an average Knee Score of 85.1 points, were achieved in 92 % of the implants. The total outcome characterized by an average Functional Score of 64.9 points was related to a higher average age of our patients and a high proportion of patients with diseases of other joints, which interfered with overall mobility and self-sufficiency. The results of implant position evaluation, based on X-ray examination, showed good values, which testifies to the use of an appropriate surgical technique and accuracy of the instrumentation applied. The occurrence of radiolucent lines was low, as was the number of complications. Our results are comparable with those reported in the literature. CONCLUSIONS: Our short-term evaluation shows that the S. V. L. implant is fully useful for total knee replacement in patients of higher age categories.

Aged↗
PubMed1981

Experimental encephalitis induced by various strains of mumps virus.

Non suppurative periventricular encephalitis and lymphoid infiltration of choroid plexus were induced by intracerebral inoculation of non neuroadapted strains of mumps virus in cercopithecus monkeys. Inflammatory lymphoid infiltration showed an obvious connection with a mild damage of ependymal cells. No signs of neuronal involvement and no inclusions were seen in light microscopy. Proliferation of viral microtubules, though without the typical budding of virions, were visible in ependymal cells in electron microscopy. Subependymal and inflammatory cells which clearly take no part in the virus proliferation were affected by the alteration.

Animals↗
PubMed1976

Ability of temperature-sensitive mutants of the recombinant influenza S/N (H2N1) virus to induce immunity to parental (H0N1 and H2N2) viruses.

The behavior in mice of two thermosensitive (ts) mutants (denoted ts217 and ts700) of the recombinant influenza virus S/N (H2N1) was studied. The parental thermoresistant (tr) virus and both of the mutants were capable of inducing protection against pneumotropic A/Singapore (H2N2) and A/WS (H0N1) challenge viruses. Immunity against the Singapore virus, with which the S/N virus shared the hemagglutinin, developed earlier than against the WS virus, with which the S/N virus shared the neuraminidase. The tr and ts217 viruses were immunologically more active than the ts700 virus. The first two viruses grew markedly better in mouse lungs than did the latter. In the course of ts217 virus replication in vivo, revertants capable of growing at 39 degrees C appeared readily. On the other hand, the ts700 virus proved to be genetically stable. These data seem to provide evidence of a linkage between the stability of the ts phenotype, reproductive capacity in mouse lungs, and immunogenicity in the viruses examined.

Antibodies, Viral↗
PubMed1976

Pathogenicity, immunogenicity and genetic stability in mice and ferrets of a cold inhibitor-resistant mutant of influenza H3N2 virus.

A cold inhibitor-resistant mutant was derived from MRC-2 virus by means of serial passages in the presence of rabbit serum and at gradually decreasing temperatures. This virus, denoted MRC-2 IRc, grew well at both 26 and 37 degree C. The pathogenicity and immunogenicity of the virus was examined in mice and ferrets. No clinical reactions were detected in either species. Both mice and ferrets developed high levels of hemagglutination inhibition and neuraminidase inhibition antibodies. The virus was reisolated from the lungs of intranasally inoculated mice; in ferrets it was recovered from nasal washing and trachea but not from lungs. The properties of the isolated viruses were examined. The viruses reisolated from mice lost their reproductive capacity at 26 degree C and were less resistant to inhibitors than the original virus. The virus isolated from the ferret nose was identical with the original virus, however the tracheal isolate exhibited a certain degree of reversion in both the markers tested.

Animals↗
PubMed1976

Experimental live tick-borne encephalitis vaccine (Labgat E5 "14" virus clone): volunteers 1 and 2 years after single-dose immunization.

Groups of volunteers given intramuscularly 5 or 6.5 dex or perorally 6.5 dex newborn mouse icLD50 of the plaquesegregated "14" clone of the Langat E5 virus strain (tick-borne encephalitis comples) were followed for periods of 12 and 24-27 months. Circulating specific virus neutralizing antibodies persisted in them in the absence of apparent reaction as evidenced by clinical, electroencephalographic and cerebrospinal fluid findings.

Administration, Oral↗
PubMed1976

Ts mutant of NWS influenza virus: behaviour in vitro and in vivo.

After passaging the NWS influenza virus at increasing temperatures in the hamster embryo fibroblast (HEF) cell line, a temperature-resistant (tr) mutant which grew well at 39 degrees C was isolated. Attempts were made to isolate temperature-sensitive (ts) mutants from the tr virus. After growth in the presence of 5-fluorouracil, 233 virus clones were isolated. Among these only one was incapable of replicating at 39 degrees C. The physiological studies, the shift-up experiment and the electron microscopic investigation suggested that the genetic defect responsible for its ts character influenced a late function of the virus genome. In the lungs of intranasally infected mice, the ts mutant replicated to a lesser extent than the tr virus. During its growth in vivo, the ts virus exhibited a high degree of genetic stability.

Animals↗
PubMed1976

Replication dynamics of tick-borne encephalitis virus in, and glycolytic activity of, human diploid cells.

Tick-borne encephalitis (TBE) virus (Western subtype) strains replicated very rapidly in human diploid embryonic lung (HDEL) cells, namely within the first 24 hours of infection. Greater amounts of both intra- and extracellular virus were produced after inoculation of a virulent than of an attenuated strain. With the virulent strain, more infectious virus was found in the medium than in the cells: the opposite was true for the attenuated strain. No cytopathic effect was observed during the period studied. The rates of glucose uptake and lactate production by cells were markedly influenced by the infection. Lactate production was retarded by both virus strains to a comparable degree. Glucose uptake was markedly increased, appreciably more so after infection by the virulent than the attenuated strain. A method for differentiating between attenuated and virulent strains based on the determination of glucose conthe medium was developed.

Cell Line↗
PubMed1975

Further virological and clinical investigations on the attenuated E5"14" virus from the tick-borne excephalitis complex.

A total of 22 persons, given a single intramuscular dose of 3.1 times 10(6) newborn mouse ic LD50/ml of the E5"14" virus (stored for 26 months at 4 degrees C in lyophilized state), were subjected to rigorous clinical, clinical-laboratory and virological investigations. Clinical observations and laboratory tests (blood and cerebrospinal fluid cytology and biochemistry) revealed no ill-effects or deviations attributable to the immunization procedure. After administration of the immunizing dose, no viraemia was detected and specific seroconversions from negativity to positivity were found after 9 weeks in 73-82% of the subjects, using different tick-borne encephalitis (western subtype) viruses in the virus neutralization experiments. The results obtained seem to give increased confidence in the further use of this attenuated virus clone with strictly defined characteristics.

Adult↗