Biomedical subjects
Publications and source records attributed to D Kohn.
Isolated avulsion of the biceps femoris tendon is a relatively rare condition. We report a case of a 43 year-old soccer player with a rupture of the biceps femoris tendon which occurred in a hyperextension of the knee. Based on this case, we discuss the literature referring to injury pattern and treatment.
Gene therapy in orthopaedic surgery is being intensively studied in the context of different genetic and nonmendelian diseases. Experimental progress in this area is characterized by the complexity of gene vector selection and production, gene transfer technology, application routes, choice of animal models, and evaluation of its efficacy using structural and functional parameters. The first clinical studies for gene therapy of rheumatoid arthritis already demonstrated their practical feasibility. Current data indicate that gene-based therapies are effective in promoting the repair of articular cartilage, and bone defects. Such strategies may lead to the development of novel molecular therapies treatments in orthopaedic surgery.
Traumatic articular cartilage lesions have a limited capacity to heal. We tested the hypothesis that overexpression of a human insulin-like growth factor I (IGF-I) cDNA by transplanted articular chondrocytes enhances the repair of full-thickness (osteochondral) cartilage defects in vivo. Lapine articular chondrocytes were transfected with expression plasmid vectors containing the cDNA for the Escherichia coli lacZ gene or the human IGF-I gene and were encapsulated in alginate. The expression patterns of the transgenes in these implants were monitored in vitro for 36 days. Transfected allogeneic chondrocytes in alginate were transplanted into osteochondral defects in the trochlear groove of rabbits. At three and 14 weeks, the quality of articular cartilage repair was evaluated qualitatively and quantitatively. In vitro, IGF-I secretion by implants constructed from IGF-I-transfected chondrocytes and alginate was 123.2+/-22.3 ng/10(7) cells/24 h at day 4 post transfection and remained elevated at day 36, the longest time point evaluated. In vivo, transplantation of IGF-I implants improved articular cartilage repair and accelerated the formation of the subchondral bone at both time points compared to lacZ implants. The data indicate that allogeneic chondrocytes, transfected by a nonviral method and cultured in alginate, are able to secrete biologically relevant amounts of IGF-I over a prolonged period of time in vitro. The data further demonstrate that implantation of these composites into deep articular cartilage defects is sufficient to augment cartilage defect repair in vivo. These results suggest that therapeutic growth factor gene delivery using encapsulated and transplanted genetically modified chondrocytes may be applicable to sites of focal articular cartilage damage.
The management of knee osteoarthritis requires a combination of both non-pharmacological and pharmacological treatment modalities. Non-pharmacological therapies include patient education, lifestyle modification, weight reduction, regular exercise, physiotherapy and the use of orthopaedic appliances (canes, insoles, braces). Pharmacological treatment includes the application of non-opioid or opioid analgetics, non-steroidal anti-inflammatory drugs or coxibes and intra-articular glucocorticoids. Glucosamin, chondroitin sulphate and hyaluronic acid are safe and provide symptomatic relief while their therapeutic effects remain uncertain.
Valgus-producing osteotomy of the proximal tibia is a well-established treatment for medial femorotibial osteoarthritis in the varus knee. The ideal patient is active, under 55 years of age, has a stable varus deformity of less than 10 degrees, a good bone stock, and an osteoarthritis stage that is restricted to the medial compartment of the knee. Coventry reported a failure rate in proximal tibial osteotomy to be significantly higher when the postoperative alignment was less than 8 degrees of anatomical valgus. Hernigou noted better clinical long-term results in cases with a precise correction of malalignment. There are different preoperative planning methods varying between simple estimates of correction angles and specific radiographic planning tools. The reproducibility of operative outcome with regard to a predictable anatomic alignment and functional recovery must have high priority. This chapter deals with different preoperative planning methods to improve the reliability of surgical results after tibial osteotomy.
In high tibial closing-wedge osteotomies (HTO), closure of an osteotomy gap after resection of a bony wedge can be associated with a fissure of the medial cortex of the tibial head (MCT). The effect of a broken MCT on the recurrence of varus deformity is disputed. In this study, serial roentgen stereometric analysis (RSA) was used to determine the fixation stability of a rigid internal "L" plate after HTO. Full weight lower limb radiographs were used to determine the sagittal alignment in patients with varying degrees of varus malalignment and correction over time. Forty-two patients with varus gonarthrosis stage I-III (Ahlback) were treated with HTO and internal fixation with an L-shaped rigid plate. Patients were followed by serial RSA, conventional radiographs, and clinical evaluation (Hospital of Special Surgery score) over a 12-month period. In 19 of 42 successive patients, an average wedge size of 6.9 degrees was resected leaving the MCT intact (group 1). In 23 of 42 of patients, the MCT was unintentionally fissured during surgery when an average 10.3 degrees -wedge was resected (group 2). In group 2, RSA revealed a fivefold increase in lateral displacement of the distal tibial segment within 3 weeks after HTO. Twelve weeks after HTO, translations between tibial segments were below the accuracy of the RSA setup in the majority of patients. Group 1 patients demonstrated a higher initial fixation stability, less occurrence of varus deformity, and a higher HSS score compared to patients with larger wedge sizes and frequent fracture of the MCT (group 2). Before bone healing is achieved, the integrity of the MCT plays a crucial role for the clinical and radiological outcome after HTO.
Anteromedialization of the tibial tubercle (Fulkerson operation) predictably leads to pain reduction and better function in initial and moderate patellofemoral arthritis. This has been shown in the literature and is supported by our own results. The indication is based on symptoms, clinical evaluation, X-rays, and MRI. The Fulkerson operation combines recentering of the patella and reduction of patellofemoral pressure. Aftertreatment together with rehabilitation last for 6-8 months because anteromedialization leads to temporary destabilization of the proximal tibia. Proximal tibial fracture is a complication of Fulkerson operation if the tibia is stressed too early.
Ganciclovir-resistant cytomegalovirus (CMV) infection is an emerging problem in transplant recipients. Foscarnet resistance and cidofovir resistance have also been described, but no previous reports have suggested treatment regimens for patients with CMV refractory to all three of these drugs. Leflunomide, an immunosuppressive drug used in rheumatoid arthritis and in rejection in solid-organ transplantation, has been reported to have novel anti-CMV activity. However, its clinical utility in CMV treatment has not been described previously. We report an allogeneic bone marrow transplant recipient who developed CMV infection refractory to sequential therapy with ganciclovir, foscarnet, and cidofovir. The patient was ultimately treated with a combination of leflunomide and foscarnet. Both phenotypic and genotypic virologic analysis was performed on sequential CMV isolates. The patient's high CMV-DNA viral load became undetectable on leflunomide and foscarnet, but the patient, who had severe graft-versus-host disease (GVHD) of the liver, expired with progressive liver failure and other complications. We concluded that leflunomide is a new immunosuppressive agent with anti-CMV activity, which may be useful in the treatment of multiresistant CMV. However, the toxicity profile of leflunomide in patients with underlying GVHD remains to be defined.
Degenerative arthritis of the knee joint is a common problem of the middle-aged patient. Primary arthritis has to be distinguished from secondary disease caused by malalignment, instability or trauma. The key symptom is pain at the jointline on weight-bearing. Diagnosis is established from history, clinical and radiological examination. Treatment options are chosen depending on the severity of symptoms and the demands of the patient. They range from modification of sports- and recreational activities, nonoperative therapy to operative options such as resecting arthroscopic procedures, repair of damaged articular cartilage, osteotomy and unicompartmental knee arthroplasty. However, the patient has to be made aware that a cure for this disease remains to be found.
108 world class athletes (54 males, 54 females) practicing modern pentathlon had been interviewed about their individual training and competition efforts as well as their sports related injuries, damages and diseases in the last world cup season using a standardized empirical questionnaire. The mean training extent was about 25 hours per week, the mean number of national and international competitions athletes made was 9, especially concerning swimming and running. Mean number of health threatening incidents of each athlete had been 2 with 41% diseases such as otitis and pharyngitis, 23% injuries such as contusions and distortions and 33% damages such as tendinitis, periostitis and strains. Head and neck involvement were more frequent than those of pelvis and the lower extremities. Training efforts were the most frequent reasons for health threatening events (84%), especially concerning diseases and damages, whereas most of the injuries happened during competitions (p<.01). Most of the injuries happened practicing horse riding during competitions (9%). Running was the most frequent reason for damages, whereas horse riding is the leading cause for injuries, furthermore damages and injuries are typical for fencing. Swimming is often associated with diseases. In contrary shooting did not show typically affiliated health threatening events. The incidence of health threatening incidents concerning world class athletes practicing modern pentathlon is quite low. Especially running and swimming combined with a high training extent empirically predisposed to suffer from damages and diseases. Horse riding with a quite low training extent and fencing show a higher incidence of injuries. From the training-methodological point of view the training extent should not be too extended. Due to a high number of diseases it may be profitable to be in attendance of an inner medicine physician.
In this case report we present a male soccer player suffering from chronic groin pain. Exact diagnosis, i. e. seminal vesiculitis, could finally be evaluated by the means of MR Imaging, and so the patient did fully recover after selective antibiotic therapy. In this case musculoskeletal involvement because of visceral pelvic disorders may be caused by synaptic interaction between the somato-sensory and viscero-motoric system due to the close anatomical relationship between the seminal vesicle of the pelvis and the pubic bone with its insertion of the adductor muscles. In case of chronic groin pain in athletes physicians should also be aware of visceral pelvic disorders. For diagnostic evaluation MR Imaging may be of important help.
PURPOSE: Numerous new all inside meniscus repair techniques using biodegradable fixation devices have become available in the last years. Few studies have dealt with the biomechanical properties of these implants so far. The aim of this study was to analyze meniscus repairs under cyclic loading conditions for different fixation devices (Meniscus Arrow, Clearfix Meniscal Screw, Meniscal Dart, BioStinger) and to compare them to standard suture techniques. MATERIAL AND METHODS: Eighty meniscus repairs on 27 medial porcine menisci were performed. For biomechanical testing loosening, number of failures, failure modes and failure loads were evaluated under cyclic and maximum loading conditions. Testing was performed on a materials testing machine. RESULTS: During cyclic loading 10 out of 40 (25%) fixation devices failed. A gap appeared between the 2 parts of the meniscus within the first loading cycles. The failure strengths obtained with the 4 meniscus fixation devices did not differ significantly (Meniscus Arrow: 44 N; Clearfix Meniscal Screw: 35 N; Meniscal Dart: 33 N; BioStinger: 54 N). Besides for the BioStinger, the values of the sutures were significantly higher. The use of a stronger suture material (PDS 0) increased the failure load significantly. During maximum loading the fixation devices failed by both pull-out of the head or the tip of the device, except for the BioStinger showing only pull-out of the head. All sutures failed by breakage, except for the PDS 0 horizontal sutures in which 50% of complete tissue failures could be noted. CONCLUSION: This study shows that meniscal fixation devices may fail under repetitive loading conditions. A gap appeared between the meniscal margins within the first loading cycles irrespective of the suture type and fixation device used. Both gapping and failure modes of the fixation devices may be design-specific. The maximum failure loads differed significantly between the bioabsorbable devices and the sutures. Stronger suture materials increased the failure loads significantly. To allow a complete evaluation of new meniscus fixation devices not only biomechanical, but also biological and clinical parameters need to be analyzed in forthcoming studies.
Precise digital data of the internal femoral anatomy are necessary to develop new prosthetic implants with computer-aided design (CAD) techniques. Thirty human cadaveric femurs of central European origin were analysed by high precision computed tomography (CT) using thin slice and high resolution imaging. The CT data were image processed with thresholding to obtain a reconstruction of the cortical bone geometry. The CT threshold for cortical bone was optimized by comparison with saw cuts of macerated femurs. For each specimen a three-dimensional (3D) model of the cortical femur was calculated by the CAD system based on the processed CT data. Virtual 3D models of the 30 femurs were used to adjust a hypothetical stem to the proximal femur anatomy by repeated virtual implantations. The CAD system allowed for evaluation of anatomical parameters after hip reconstruction, amount of bone removal, and cortical bone contact. The fit and fill of the stem could be tested before clinical application and implant-related problems could be corrected.
The bone-patellar tendon-bone graft (BTPB) was the most commonly used graft for many years. The scientific database is more complete than for every other graft option. This review article presents the surgical techniques of ACL reconstruction with the BPTB graft, aspects of rehabilitation, clinical results, and postoperative problems with special emphasis on donor site morbidity.
Clinical examination has remained the key for diagnosis of meniscal and ligament lesions of the knee. Economical use of imaging techniques is based on adequate clinical examination. Standard radiographic examination is still a simple and valuable method. Magnetic resonance tomography has made great progress during the past few decades. For this reason, this article centers on this imaging modality.
The objective of our study was to clarify whether the phentolamine test is as suitable as sympathetic blockade in diagnosing cases of sympathetically maintained pain. The specificity and the sensitivity of both procedures were examined within a prospective and randomized study. Both a local sympathetic blockade and an intravenous phentolamine infusion were carried out in 29 patients with persistent pain in the area of the upper or lower extremities. A significant improvement was defined as reduction of pain of at least 50%. There were no complications in either test procedure. The phentolamine test registers sympathetically maintained pain well when it has a positive result (specificity of 83%). However, the phentolamine test shows only a low sensitivity of 69%. The phentolamine test, on the other hand, can be realized very easily and safely. Therefore, based on the results obtained, it is recommended that the phentolamine test be applied for primary diagnosis. In case of a negative result, further diagnosis should follow subsequently, for example with local sympathetic blockade.
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