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Biomedical subjects

C Perka

Publications and source records attributed to C Perka.

54 records · Page 3Linked to original sources
PubMed1999

Bone engineering on the basis of periosteal cells cultured in polymer fleeces.

Large bone defects caused by severe trauma, infection or tumor resection are still a major challenge for orthopaedic surgery. The key concept for successful bone regeneration consists of combining the osteoinductive effect of osteogenic cells with a suitable carrier structure to promote osteoblastic differentiation and optimal matrix production. Therefore, periosteal cells cultured in polyglycolic-polylactid acid (PGLA) fleeces were investigated for their osteogenic differentiation and used to repair critical size bone defects in a rabbit model. Periosteal cells were isolated from New Zealand White rabbits and expanded in vitro. Osteogenic differentiation was investigated by analysis of alkaline phosphatase and osteocalcin production in vitro depending on culture conditions and passage number. Cells were seeded into PGLA fleeces. After further cultivation, tissue constructs were examined histologically and by immunohistochemistry for cell distribution and osteogenic differentiation. These constructs of defined size were used to repair critical size calvarial defects (group I) in rabbits compared to a defect repair with polymers only (group II) or to untreated defects (group III). Bone healing was evaluated after 4 weeks by radiodensitometry and a special histological scoring system. For early evaluation, radiodensitometry was not sensitive enough to detect differences in calcification. However, on histologic examination the group with cell/fleece constructs revealed intense formation of uncalcified bone. The mean defect closure of the experimental group I was 65%, compared to control groups II and III with 31% and 22%, respectively. The established methods of 3-D-cell culture and ex-vivo transplant assessment proved to be a valuable tool for quality assurance. The results demonstrate that the combination of periosteal cells and polymer fleeces is a tissue engineering approach, which may have clinical applications in various fields of reconstructive surgery.

Journal Article↗
PubMed1998

[Pregnancy-induced algodystrophy].

Pregnancy-induced algodystrophy is per se a rare, possibly too rarely diagnosed disease, since patients with algodystrophy may be misdiagnosed as having unspecific backache, musculoskeletal problems, and ligament pain associated with pregnancy. However, when clinical signs of beginning algodystrophia are present, immediate investigations and therapy are necessary for relief of pain and in order to prevent complications. The aim of this paper is to summarize our current knowledge on this disease. Furthermore, the clinical course and diagnostic evaluation are described in two cases with pregnancy-induced algodystrophy. The authors question the common distinction between pregnancy-induced and post-pregnancy algodystrophy, which result in a disturbed bone and calcium metabolism, but discuss both entities similary.

Calcitonin↗
PubMed1997

Surgical management of severe spondylolisthesis in children and adolescents. Anterior fusion in situ versus anterior spondylodesis with posterior transpedicular instrumentation and reduction.

STUDY DESIGN: A clinical and radiologic retrospective follow-up examination of patients treated surgically for severe juvenile spondylolisthesis. OBJECTIVE: To compare two different surgical techniques in the management of severe (degree of slip > 30%) juvenile spondylolisthesis (anterior spondylodesis in situ versus combined anterior spondylodesis and posterior transpedicular instrumentation including reduction of the slipping vertebra) to determine if the advantages of the repositioning of the slipping vertebra and a decreased number of pseudarthroses because of the transpedicular instrumentation lead to clinical improvement despite showing better alignment radiologically. METHODS: This study included 59 children and adolescents with severe spondylolisthesis of L5 who were treated surgically at the authors' orthopedic department between 1980 and 1992. Twenty-nine children received anterior spondylodesis (AS group), and 30 children received, in addition, a posterior reduction and transpedicular instrumentation (posteroanterior spondylodesis, PAS group). RESULTS: Distribution of age, gender, preoperative clinical symptoms, and preoperative radiologic classification of the spondylolisthesis were comparable in both groups (average degree of slip for the AS group, 66%; that for the PAS group, 75%; angle of slip, 28 degrees and 36 degrees, respectively; sacral inclination, 31 degrees and 25 degrees, respectively). The postoperative follow-up period of the AS group lasted 125 +/- 22 months, considerably longer than that of the PAS group at 67 +/- 20 months. At the time of the follow-up assessment, the PAS group showed a reduced rate of pseudarthrosis (7% versus 24%), a reduced degree of slip (36% versus 59%), and a reduced lumbosacral kyphosis (14 degrees versus 26 degrees) in comparison with the AS group. The transpedicular instrumentation decreased the fusion time of osseous consolidation of the spondylodesis markedly (7 months versus 17 months, on average). Adverse effects and rate of complications were equal in both groups. The results failed to show any differences in favor of either of the two surgical techniques used either subjectively to the patient or objectively by means of clinical examination. CONCLUSION: Anterior spondylodesis including posterior instrumentation and reduction was superior to the simple anterior fusion in situ for normalization of the lumbosacral profile and osseous consolidation of the spondylodesis. This result was not reflected in the clinical evaluation.

Adolescent↗
PubMed1996

[Tissue engineering of human cartilage tissue for reconstructive surgery using biocompatible resorbable fibrin gel and polymer carriers].

Current practical approaches in cartilage engineering still face problems with three dimensional cell distribution or require components for cell immobilization, raising biocompatibility problems. In this study, we present a new model using cells cross-linked by fibrin within biocompatible resorbable polymers. Both components have been in clinical use for a long time. Immunohistochemical procedures showed that this model provides optimal requirements for in vitro cartilage production. Immunochemically, cartilage-specific extracellular components such as proteoglycan, chondroitin sulfate and collagen II were characterized. Histomorphological methods showed a mechanically stable tissue compound that lasted for at least 5 weeks. This model may be the first to provide all biocompatible requirements for in vitro production of autologous cartilage transplants for reconstructive surgery.

Biocompatible Materials↗
PubMedDate not supplied

[Total endoprosthetic management of the hip joint after failed osteosynthesis of para-articular hip fracture].

OBJECTIVE: Treatment of fractures of the proximal femur by open reduction and internal fixation is prone to complications and frequently requiring secondary joint replacement. The aim of the present study was to examine the results of total hip arthroplasty as a salvage procedure for failed internal fixation of femoral or acetabular fractures. PATIENTS AND METHODS: We retrospectively studied 145 patients who had undergone 146 total hip arthroplasties for failed internal fixation of femoral (n = 135) or acetabular fractures (n = 11). Mean follow-up time after insertion of the hip endoprosthesis was 7.1 years (1.5-14.7 years). Patient evaluation included a history, clinical examination, and standard radiographs. RESULTS: Twenty-eight patients had died, and 18 patients were lost to follow-up. Kaplan-Meier analysis with revision of the implants as the end-point demonstrated 85 percent survival after ten years. Using the Merle d'Aubigné rating system, we found good or excellent results in 85 percent of the cases. However, only 73.9 percent of the patients were satisfied with their result, and 40.9 percent still showed a positive Trendelenburg gait at follow-up. The perioperative mortality was 2.7 percent. Surgery-related femoral fractures or fissures were observed in 18 cases, and deep infections in four. CONCLUSIONS: In comparison with data of patients who had undergone primary total hip arthroplasty for osteoarthritis in our department, the results reported here after secondary hip replacement are clearly inferior. Nonetheless, alloarthroplasty of the hip still is the most effective procedure after failed internal fixation for acetabular or proximal femoral fractures.

Adult↗
PubMedDate not supplied

[Kinetic and kinematic gait analysis before and after total knee endoprosthesis implantation].

OBJECTIVE: The aim of the present paper was to make an objective assessment of the surgical outcome after primary knee endoprosthesis implantation by means of gait analysis. METHOD: Kinetic and kinematic parameters of gait pattern were recorded using multi-component measuring platforms integrated into a treadmill and an optoelectric measuring system. 20 patients were investigated preoperatively and on average 14 and 28 weeks postoperatively. RESULTS: Preoperatively, on the affected side, the leg was used for a shorter time, but with much higher maximum forces. Mobility was reduced in the affected joint, in the adjacent hip joint, and in the contralateral joints when walking. After endoprosthesis implantation, the gait pattern approximated that of the reference group. The gait symmetry increased, and the time and force-related loading of the operated leg and the extent of mobility of the contralateral knee and both hips increased up to 28 weeks postoperatively. The clinical score according to Aichroth et al. showed a correlation with the measured values of the gait analysis at all times (p < 0.05). CONCLUSION: Mono-articular degenerative changes of the knee have a negative effect on the function of adjacent and contralateral joints. Endoprosthesis implantation then leads to a normalisation of pathological motion patterns, both in the operated and in the adjacent and contralateral joints. However, normal values were not yet achieved 28 weeks postoperatively, which demonstrates the possibility for further functional improvement depending on the continuity of rehabilitation.

Aged↗
PubMedDate not supplied

[Periprosthetic osseous changes 2, 4, and 6 years after implantation of cementless Zweymüller-stems-- A cross-sectional study].

AIM: According to the results of longitudinal studies, the use of distally anchored femoral prostheses leads to marked proximal stress shielding. Zweymüller stems should be controlled some years after implantation. METHOD: In a cross-sectional study, we examined 92 patients clinically, radiologically, and osteodensitometrically 2, 4, and 6 years after implantation in order to assess the osseointegration of Zweymüller shafts as independently as possible of age. The non-operated contralateral limb or Gruen's zone 4 below the prosthesis was used as a control group. RESULTS: At no time did the parameters assessed indicate any reduction in proximal bone density as compared with the control group. Zone 7 (medial-proximal) even showed an increase in bone density after 2 and 4 years. Nevertheless, absolute bone density was lowest proximally both pre- and postoperatively. Six years after implantation women even showed a 15 % increase in summated periprosthetic bone density as compared with the control group. No influence of femoral shape on bony remodeling was demonstrated. CONCLUSION: Periprosthetic bony remodeling cannot be attributed exclusively to the shape of the shaft. Longitudinal studies do not adequately reflect the reduction in periprosthetic bone mass that occurs as a function of age and altered activity level. The osseointegration of hip prostheses is influenced by other factors such as musculoskeletal lines of force, sex, and age.

Adult↗
PubMedDate not supplied

[Early postoperative functional differences between total knee arthroplasties supplied with mobile-bearing platform or fixed-bearing system--an analysis of gait pattern].

AIM: The goal of this study was to analyze differences of gait patterns among patients with total knee arthroplasty supplied with mobile-bearing platform in contrast to patients supplied with fixed-bearing knee systems. METHOD: For that reason 17 patients with mobile-bearing knee systems and two groups of 15 patients each with fixed-bearing knee systems have been examined clinically, radiologically, and by means of gait analysis up to 6 months postoperatively. Additionally 20 knee-healthy control subjects have been gait-analyzed for comparison. RESULTS: There existed no different developments of gait characteristics between the groups of patients in the preoperative status. After the operation an increase of the ground reaction force of the operated leg was observed in all groups. The functional range of motion in the operated knee joint improved among patients postoperatively. Besides, in the group with the mobile-bearing knee a significantly stronger flection of the operated leg during the stance phase under load could be proven. Between the groups of patients the average values of the respective radiological alignments did not exhibit statistically significant differences. No severe complications have been observed. CONCLUSION: For the group of patients with fixed-bearing knee course samples have been registered, which approximate the reference values of healthy control subjects more strongly. The entire course sample is characterized by an increased range of motion of the opposite side and the adjacent joints. The parameters measurable in the gait analysis point to a better biomechanical situation after implantation of the mobile-bearing system.

Adult↗
PubMedDate not supplied

[Application of a dynamic pedicle screw system (DYNESYS) for lumbar segmental degenerations - comparison of clinical and radiological results for different indications].

AIM: Evaluation of the efficacy of a dynamic stabilizing system for different indications using medium-term clinical and radiological parameters. METHODS: Out of a total of 70 evaluated patients, 35 showed initial disc degeneration and disc herniation (group 1). In this group, additional nucleotomy was performed. Group 2 included 22 patients with initial osteochondrosis and facet joint osteoarthritis. 13 patients suffered from progressive segment degeneration or degenerative spondylolisthesis (group 3). Clinical evaluation was performed preoperatively, three months postoperatively and at follow-up (33 months). Examinations included subjective and objective measures using the Oswestry Index and VAS as well as radiographs and MRI. RESULTS: Oswestry Index and VAS improved significantly in groups 1 and 2 and remained improved until follow-up. Group 3 showed no significant changes. The evaluation of radiographs and MRI of groups 1 and 2 revealed no progression of the degeneration either at the operated segments or at the adjacent segments. In group 3, 9 cases of progressive degeneration of the operated segments and 3 cases of adjacent segment degeneration were found. Out of 5 implant-associated complications 4 were observed in group 3. CONCLUSION: Dynesys is able to compensate initial morphological changes and to prevent progression of segment degeneration. The system seems not to be indicated for treating marked deformities or if osseous decompression needs to be performed.

Adult↗
PubMedDate not supplied

[Indications and implementation of recommendations of the working group "Tissue Regeneration and Tissue Substitutes" for autologous chondrocyte transplantation (ACT)].

For the treatment of full-thickness articular cartilage lesions of the knee joint, as a result of trauma or osteochondritis dissecans, a variety of biological reconstruction techniques have been developed. Different studies, some of which were performed as randomised, prospective clinical studies, showed that the autologous chondrocyte transplantation (ACT) provides the most satisfying and reliable method of cartilage reconstruction in the adult when applied to defects exceeding 4 cm (2). Based on these results, ACT seems to be of economic benefit, as the risk of developing osteoarthritis correlates significantly with the size of the cartilage defect, when not treated properly and in time. Surveying the studies on basic scientific aspects of ACT, cartilage defect animal models and clinical studies, it can be concluded that clinical results of ACT depend on a variety of factors. In this review, published by the joined advisory board of the German Societies of Traumatology (DGU) and Orthopaedic Surgery (DGOOC), we summarize the current knowledge available and the state of the art concerning ACT. Especially we discuss the advantages of different procedures, methods for treating knee cartilage defects and factors that influence the outcome of the different treatment regimens, with the aim to develop guidelines for the correct indication and application of the ACT.

Adult↗
PubMedDate not supplied

[The effect of osteoprotegerin on tendon-bone healing after reconstruction of the anterior cruciate ligament: a histomorphological and radiographical study in the rabbit].

AIM: Improvement of the bony incorporation of a soft-tissue graft after ACL reconstruction by local administration of Osteoprotegerin between the bone and tendon graft. METHOD: Fifteen New Zealand White rabbits underwent unilateral anterior cruciate ligament (ACL) reconstruction using an autologous semitendinosis tendon graft. We compared the effect of three OPG doses (5 microg, 50 microg, or 100 microg) at the tendon-bone interface to the controls (OPG carrier) and ACL reconstruction only. Specimens were analyzed at 3 weeks using radiology, histology and histomorphometry to investigate the effect of OPG on the bony incorporation of the tendon graft. RESULTS: Animals treated with OPG 100 microg had a significant (p = 0.007) increase in newly-formed bone around the graft compared to the control group (0.16 +/- 0.01 mm(2); 0.06 +/- 0.02 mm(2)). No significant differences were found between the controls and the other groups (tendon graft only, OPG 5 microg, and 50 microg) (p > 0.05). Bone mineral density, measured in image-pixel brightness (IPB; reference range: 0-255), along the edge of the bone tunnel was greater in the OPG 100 microg group (169.5 +/- 5.9 IPB) compared to the control group (150.3 +/- 4.3 IPB) but this was not statistically significant (p = 0.083). There was a significant decrease in the number of osteoclasts per high-power microscopic fields (HPF) lining the bone tunnel in the OPG 100 microg group compared to the control group (4.4 +/- 2.5 cells/HPF; 6.4 +/- 1.8 cells/HPF) (p = 0.022). No significant differences were found between the control group and the other groups in osteoclast numbers (p > 0.05). CONCLUSION: Since tendon-bone healing requires new bone formation and bone ingrowth around a tendon graft, OPG may improve biologic graft fixation. A potential implication could be earlier return to function or better conditions in revision surgery.

Animals↗
PubMedDate not supplied

[Accuracy of determination of the hip centre in navigated total knee arthroplasty].

AIM: In navigated knee arthroplasty the hip centre is determined by rotary motion of the femur (pivoting). The accuracy of this functional hip centre determination in vivo is unclear. In the following paper the accuracy of pivoting in the determination of the hip centre was examined. METHODS: Navigated (TC-PLUS, Solution, PLUS Orthopedics) total knee arthroplasty (PI Galileo, PLUS Orthopedics) was performed on 25 patients with primary arthritis of the knee joint. The position of the femoral component and the hip centre were postoperatively determined by computer tomography. Through comparison with the intraoperatively documented data, the deviation of the pivoted from the true hip centre in the frontal and sagittal planes was calculated. The degree of arthritis of the hip was determined on plain radiographs according to Kellgren. RESULTS: The mean deviation was determined to 1.0 +/- 0.7 degrees in the frontal plane and 2.5 +/- 1.6 degrees in the sagittal plane (p = 0.002). This corresponds to a mean overall deviation of 20 +/- 10 mm. The data were continuously, non-parametrically distributed without any outliers. A great range of motion (ROM) in the frontal as well as sagittal planes during pivoting resulted in a less accurate determination of the hip centre. There was no correlation to the degree of arthritis of the hip. CONCLUSION: The results indicate a recommendable ROM during pivoting for maximal accuracy of hip centre determination of 20 to 30 degrees in the sagittal plane and 30 to 40 degrees in the frontal plane. Arthritis of the hip is not a contraindication for functional determination of the hip centre.

Arthroplasty, Replacement, Knee↗
PubMedDate not supplied

[Treatment of chronic plantar fasciitis with botulinum toxin A--an open pilot study on 25 patients with a 14-week-follow-up].

AIM: The conservative and operative treatments of plantar fasciitis tend to be tedious. Unsatisfactory results are common in chronic cases. This study was performed in order to test the hypothesis that the analgesic and anti-inflammatory effect of a single injection of Botulinum toxin A (BoNT A) induces a significant reduction of symptoms. METHOD: 25 patients were included and followed-up for 14 weeks. Prior to injection, all of them had undergone at least two trials of conservative treatment. To determine the optimal treatment dose, 6 patients were injected subfascially with 100 units BoNT A (Dysport), another 6 with 200 units BoNT A. As result of this pre-trial, another 13 patients were treated with the higher dose. The patients documented maximum pain and continuous pain on a visual analogue scale. The strength of the lower leg and foot muscles was clinically assessed. RESULTS: A significant reduction of maximum and continuous pain was seen 2 weeks after injection in the group of 19 patients treated with 200 units BoNT A and persisted until the end of the follow-up. Adverse effects such as weakness of the muscles or systemic reactions have not been observed. CONCLUSION: This pilot study shows the efficacy of a single application of 200 units BoNT A as a treatment option for chronic plantar fasciitis.

Aged↗
PubMedDate not supplied

[Experimental studies of mechanically-induced articular cartilage defects following implantation of allogeneic embryonal chondrocytes in a collagen-fibrin gel in chickens].

Full thickness defects (diameter 1,7 mm; depth 2,5 mm) were created mechanically in articular cartilage and subchondral bone of the condyles of tibiotarsal joints of 9-month old chickens. This full-thickness defects were repaired with cultured allogenic embryonic chick epiphyseal chondrocytes from the tibiae and femura of 10-days-old chicken embryos. The cells were embedded in a collagen-fibrinogen-matrix. Controls were similarly operated, but received either no treatment or implants the delivery substance only. Healing of the defects was observed macroscopically, histologically, histochemically and histomorphometrically after 3, 12 and 24 weeks. This graft was successfully transplanted in mechanically induced defects in 80%. The resulting hyaline cartilage was structurally reorganized according to the host pattern and under the influence of environmental conditions. The articular zone preserved it's cartilaginous phenotype, whereas the subchondral regions were transformed into bone. 12 weeks after the operation the defects in the experimental group were completely filled. In all instances in this group, there was an initial extreme increase of mitotic rate and cell number. After 24 weeks normal and subnormal values were founded. The defects in the control groups healed with fibrocartilage. Our results showed, that only the defects in the experimental group were completely filled with reparative hyaline cartilage tissue. In the present study the mixture of cultured allogenic embryonic chondrocytes and a collagen-fibrinogen-matrix was used successfully as a transplant for repairing defects in articular cartilage of chickens. Thus allogenic transplantation of cultured embryonal chondrocytes appears to be one of the most promising methods for the restoration of articular cartilage.

Animals↗
PubMedDate not supplied

Competitive sports and the progression of spondylolisthesis.

To consider the effects of several years of competitive sports training on children and adolescents with spondylolisthesis, we carried out a retrospective radiologic and clinical study of 86 young athletes with spondylolysis or spondylolisthesis (24 girls and 62 boys between the ages of 6 and 20 years). The mean degree of displacement was 10.1% at the beginning of the observation. The radiologic tests showed an increase in displacement over time in 33 athletes. The average progression of spondylolisthesis in this group was 10.5%. For 36 athletes, spondylolisthesis did not progress during the period of athletic training. In seven athletes, a decrease in the displacement was observed, from 17.9 to 8.9% on average. For 10 athletes, the course of spondylolisthesis could not be determined, because only one lateral radiograph was available. In spite of intensive daily training, the athletes had no symptoms during the entire period of observation, which lasted an average of 4.8 years. In light of our experiments, there is no justification for generally advising children and adolescents with limited spondylolytic spondylolisthesis not to take part in competitive sports.

Adolescent↗
PubMedDate not supplied

Joint cartilage repair with transplantation of embryonic chondrocytes embedded in collagen-fibrin matrices.

OBJECTIVE: The objective of this study was to assess the feasibility of transplanting embryonic chondrogenic cells within a collagen-fibrin substrate for the reconstitution of full-thickness cartilage defects in chicken knee joints. METHODS: Full-thickness cartilage defects were created mechanically on the weight-bearing surface of the tibial condyle in 45 adult chickens and subsequently filled with chondrocytes embedded in a chondrocyte-collagen-fibrin gel. The transplants were compared to untreated defects and collagen-fibrin transplants without cells. The results were analyzed using histochemical and morphometrical methods after 3, 12 and 24 weeks. A semiquantitative histological grading system was applied to evaluate the transplant integration and the newly formed cartilage architecture. RESULTS: Chondrocyte-gel grafts developed to hyaline-like cartilage without any granulation tissue in the interface after 3 weeks. After 12 weeks the defects in the experimental group were filled completely with hyaline cartilage. The defects in the control groups in all cases healed with fibrous repair tissue. CONCLUSION: Fibrin-collagen gel allowed stable graft fixation and provided an adequate microenvironment for embryonic chondrocytes to generate hyaline-like neocartilage in a full-thickness cartilage defect.

Animals↗
PubMedDate not supplied

Effects of dexamethasone and celecoxib on calcium homeostasis and expression of cyclooxygenase-2 mRNA in MG-63 human osteosarcoma cells.

OBJECTIVE: Glucocorticoids and selective COX-2 inhibitors are potent anti-inflammatory agents. They are also suggested to influence bone physiology and remodeling. Here we searched for effects of dexamethasone and celecoxib on crucial parameters of bone physiology that could be therapeutically relevant. METHODS: The human osteosarcoma cell line MG-63 was used to measure effects of these drugs on (i) intracellular calcium concentration ([Ca2+]i) using a microfluorometric technique, (ii) alkaline phosphatase and osteocalcin levels (EIA) and (iii) the expression of cox-2 mRNA (quantitative real time PCR). Measurements were performed in Vitamine D-incubated quiescent cells and in cells stimulated with TNF-alpha and IL-1beta. RESULTS: We found the cytokine-stimulation to increase [Ca2+]i which was prevented by dexamethasone already after 30 min and still after 48 h. Dexamethasone was without any effect on [Ca2+]i in quiescent cells. Celecoxib had no measurable short-term or long-term effects neither in quiescent nor in stimulated cells. Vitamin D stimulated the expression of cox-2 mRNA which was further enhanced by TNF-alpha/IL-1beta. Dexamethasone did not have any measurable effects on COX-2 expression after 30 min, but a pronounced inhibition was seen after 48 h. In contrast, celecoxib had no effect on COX-2 expression. Neither of the drugs had any effect on the secretion of alkaline phosphatase and osteocalcin. CONCLUSION: We found dexamethasone to inhibit the [Ca2+]i increase in MG-63 cells following stimulation and to reduce considerably COX-2 expression via the genomic pathway. In contrast, celecoxib did not show any measurable short-term or long-term effects on the parameters of bone physiology measured.

Alkaline Phosphatase↗