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Biomedical subjects

D Kohn

Publications and source records attributed to D Kohn.

At least 55 records · Page 3Linked to original sources
PubMed2000

[Osteonecrosis of the hip joint in adulthood. Significance of various corrective osteotomies].

The importance of osteotomies in treatment of osteonecrosis of the femoral head has decreased. However, with proper selection of the patient, osteotomies are still useful for small stage III or IV lesions in patients younger than 45 years, and with no ongoing causes for progressive osteonecrosis such as the use of high doses of corticosteroids, chemotherapy, and chronic alcoholism. For preservation of natural hip joint function, the necrotic segment is moved away from the load-transmitting area of the acetabulum, and weight-bearing forces are redistributed to articular cartilage that is supported by healthy bone. In addition to radiographic evaluation, MRI is most accurate for imaging of the stage, localization, and extent of osteonecrosis in planning and selecting osteotomy.

Adult↗
PubMed2000

[Knee endoprosthesis: aspects of surgical techniques].

The implantation of a condylar knee has remained a challenge for surgeons and the equipment of the hospital. In contrast to total hip arthroplasty, not only is the correct insertion of the implant crucial, but also the treatment of the surrounding soft tissues. Mediolateral soft tissue balance and balance between flexion and extension gaps, as well as centering the patella, have to be done carefully. The soft tissue envelope of the knee joint is thin and prone to necrosis after multiple incisions. Damage to the extension mechanism can make a total joint useless. Tearing the patellar ligament from the tibial tuberosity must therefore be avoided by all means during operation. Precise cutting of the distal femur is only possible if excellent equipment is used by a skillful surgeon. The same is true for orientating saw cuts related to the long leg axes. These tasks can probably be taken over by navigation systems and robots in the future. Because the definite choice of implants has to be made intraoperatively, a complete modular system has to be present in the hospital. Only hospitals that can properly equip their surgeons to manage upcoming soft tissue problems and bony deficiencies should offer treatment to patients requiring condylar knee arthroplasty.

Arthroplasty, Replacement, Knee↗
PubMed2000

Reliability and interobserver variability in radiological patellar height ratios.

This study evaluated the reliability and interobserver variability of five patellar height ratios as measured by two examiners on standard radiographs: Insall-Salvati (IS), modified Insall-Salvati (MIS), Blackburne-Peel (BP), Caton-Deschamps (CD), and Labelle-Laurin (LL). Plain lateral radiographs with a knee flexion angle of 20 degrees for IS, MIS, BP, and CD ratios and 90 degrees for the LL method of 22 knees of 21 patients with varying pathological knee conditions were analyzed. Statistical results revealed a low interobserver variability with high correlation coefficients (0.86 for IS, 0.82 for MIS, 0.86 for BP, 0.92 for CD, and 0.81 for LL; P > 0.3) and low mean interobserver errors. However, regarding the reliability of the radiographic results of the different methods for patella alta, baja, or norma we found varying results in 68% of the patients. In two patients the patellar height was classified as alta, norma, or baja depending on the ratio used. Regarding the definitions of patellar height used by the authors of these methods, we found the lowest number of normal patellae with the IS ratio and no patella alta for the CD ratio. The LL method revealed the highest number of patella alta. The BP ratio showed intermediate results for both patella alta and baja, being the most moderate method. This study showed that there was a good interobserver reliability for the evaluation of patellar height according to the common radiological ratios. However, the high frequency of differing results between the different radiographic ratios showed that patellar height classification as "alta," "norma," or "baja" depends heavily on the chosen index. The differing results were due mainly to the normative patellar height data and to anatomical differences. Based on these findings we recommend a ratio using the articular surface of the patella in relation to the joint line. We recommend the BP method because it revealed the lowest interobserver variability and discriminated best among the groups alta, norma, and baja.

Adolescent↗
PubMed2000

Extracorporal shock wave therapy in patients with tennis elbow and painful heel.

The aim of this study was to evaluate the effect of extracorporal shock wave therapy (ESWT) in tennis elbow and painful heel. Nineteen patients with tennis elbow and 44 patients with painful heel in which conservative treatment had failed underwent ESWT. Both groups received 3000 shock waves of 0.12 mJ/mm2 three times at weekly intervals. After a follow-up of 5 and 6 months respectively, pain measured on a visual analogue scale (VAS) decreased significantly in both groups. The success rate (excellent and good results) was 63% in tennis elbows and 70% in painful heels. ESWT seems to be a useful conservative alternative in the treatment of both conditions.

Adult↗
PubMed2000

Acute ulnar nerve compression syndrome in a powerlifter with triceps tendon rupture--a case report.

We report on the case of a bodybuilder and powerlifter who suffered from triceps tendon rupture complicated by acute ulnar nerve compression syndrome. The diagnosis was made clinically, radiologically, and sonographically. Ultrasound was helpful to demonstrate a large hematoma at the site of the injury. Early surgical intervention confirmed the presence of the hematoma compressing the ulnar nerve and led to a complete restoration of ulnar nerve and triceps muscle function. Few reports on distal triceps rupture have been published but its complication by acute ulnar nerve compression has not been reported on yet despite the close anatomical relationship of both structures.

Adult↗
PubMed2000

Effect of zinc supplementation on epidermal Langerhans' cells of elderly patients with decubital ulcers.

In the present study, Langerhans' cells (LCs) in the sacral epidermis, 8-10 cm from lesions of patients (mean age 71 years) with decubital ulcers, were compared ultrastructurally and morphometrically with those in the patients' own normal epidermis from the upper leg, before and after supplementation with 50 mg/day elementary zinc (in the form of a 220-mg tablet of Avazinc, administered once daily) for four months. Zinc intake resulted in from 80% to full healing of the decubital ulcers in the patients studied. The percentages of LCs were low in both perilesional sacral epidermis (2.07 +/- 0.71%) and in control leg epidermis (2.71 +/- 1.38%) before zinc supplementation and also afterward (2.12 +/- 0.16% and 2.59 +/- 0.88%, respectively). LCs demonstrated a more dendritic morphology after zinc supplementation: 68.15 +/- 9.28% and 77.0 +/- 3.45% of sacral and of control leg epidermal LCs, respectively, had dendrites before, and 91.52 +/- 3.43% and 84.15 +/- 3.64% of sacral and of control leg epidermal LCs, respectively, had dendrites after zinc supplementation. The LC section area in the sacral epidermis near the lesion as well as in the control leg epidermis and the number of LC granules in LC sections were not affected by zinc supplementation. The higher percentage of LCs having dendrites in the epidermis of patients with decubital ulcers after zinc supplementation may indicate that these LCs are in a more motile state, which might affect the healing process of the lesions.

Administration, Oral↗
PubMed2000

Gene therapy for adenosine deaminase deficiency.

The clinical gene therapy trials for adenosine deaminase (ADA) deficiency have defined both the potential benefits and the present limitations of gene therapy with hematopoietic stem cells (HSC). Current clinical results indicate that (a) both umbilical cord blood and neonatal bone marrow HSC can be transduced with murine retroviral-based vectors, (b) the transduced HSC can engraft in nonmyeloablated patients, (c) the frequency of HSC transduction/engraftment is low (1/10,000), (d) an in vivo selective advantage can exist for transduced T lymphoid progeny, and (e) the transduced ADA gene is not expressed in nondividing T lymphocytes. Improving the clinical results of gene therapy for ADA deficiency and other genetic diseases involving HSC will require (a) developing new vectors that express the transduced gene in nondividing cells and (b) increasing the frequency of stable HSC transduction.

Adenosine Deaminase↗
PubMed2000

The influence of avascularity on the mechanical properties of human bone-patellar-tendon-bone grafts.

Our aim was to analyse the effect of avascularity on the morphology and mechanical properties (tensile strength, viscoelasticity) of human bone-patellar-tendon-bone (BPTB) grafts in vitro. These were harvested at postmortem and stored submerged in denaturated human plasma at a constant pH, pO2, pCO2, temperature and humidity under sterile conditions. Mechanical testing was performed two and four weeks after removal of the graft. The mean ultimate strength was 1085.7 +/- 255.8 N (control), 1009.0 +/- 314.9 N (two weeks cultured) and 1076.8 +/- 414.8 N (four weeks cultured). There was no significant difference in linear stiffness or deformation to failure between the groups. There was a difference in viscoelasticity between the control group and the avascular grafts and the latter had significant lower peak load-to-load ratios after 15 minutes compared with the control group. After two and four weeks the graft contained viable fibroblasts. There was regular cellularity in the superficial layers and decreased cellularity in the midportion. The structure of the collagen including the crimp pattern appeared to be normal in polarised light. We conclude that avascularity does not significantly affect ultimate failure loads or stiffness of BPTB grafts. Slight changes in viscoelasticity were induced, but the significance of the increased stress relaxation is not fully understood.

Adult↗
PubMed2000

[In Process Citation]

Calcifying tendinitis of the rotator cuff is a common||| disorder of the shoulder which affects mainly individuals between 30 and 50||| years of age. The etiology is still a matter of speculation. The calcification||| is a reactive process actively mediated by cells in a viable environment. The||| deposit undergoes an evolution (precalcific stage--calcific stage with||| formative phase, resting period and resorption--postcalcific stage), which||| ultimately remodels normal tendon tissue. However, the evolutionary stages of||| the disease do not always follow the typical sequence. A symptomatic deposit||| may persist or postcalcific tendinitis develop. The treatment should be based||| on the knowledge of the natural history of the disease, which shows a strong||| tendency towards self-healing by spontaneous resorption of the deposit. The||| stage of evolution of the disease should be judged, combining pain history,||| morphology of the deposit on plain X-rays, and ultrasound findings. The||| therapeutic approach depends on the evolution of the disease. During the||| resorption phase we favor a conservative approach. For deposits which are not||| under resorption we propose a concept which consists of three steps: a||| conservative approach, extracorporal shock wave therapy (ESWT) or needling, and||| arthroscopic surgery. The efficacy of ESWT and needling has still to be proven.||| Patients with persisting pain after steps 1 and 2 are candidates for surgical||| removal of the deposit. We prefer the arthroscopic approach. In some cases an||| additional arthroscopic subacromial decompression (ASD) is||| indicated.

Journal Article↗
PubMed2000

[Tendinosis calcarea of the rotator cuff].

Calcifying tendinitis of the rotator cuff is a common disorder of the shoulder which affects mainly individuals between 30 and 50 years of age. The etiology is still a matter of speculation. The calcification is a reactive process actively mediated by cells in a viable environment. The deposit undergoes an evolution (precalcific stage--calcific stage with formative phase, resting period and resorption--postcalcific stage), which ultimately remodels normal tendon tissue. However, the evolutionary stages of the disease do not always follow the typical sequence. A symptomatic deposit may persist or postcalcific tendinitis develop. The treatment should be based on the knowledge of the natural history of the disease, which shows a strong tendency towards self-healing by spontaneous resorption of the deposit. The stage of evolution of the disease should be judged, combining pain history, morphology of the deposit on plain X-rays, and ultrasound findings. The therapeutic approach depends on the evolution of the disease. During the resorption phase we favor a conservative approach. For deposits which are not under resorption we propose a concept which consists of three steps: a conservative approach, extracorporal shock wave therapy (ESWT) or needling, and arthroscopic surgery. The efficacy of ESWT and needling has still to be proven. Patients with persisting pain after steps 1 and 2 are candidates for surgical removal of the deposit. We prefer the arthroscopic approach. In some cases an additional arthroscopic subacromial decompression (ASD) is indicated.

Adult↗
PubMed2000

[Ruptures of the anterior cruciate ligament (ACL) during growth].

Tears of the anterior cruciate ligament (ACL) in skeletally immature patients with open physes are becoming more frequent. The two main variants of this lesion include tibial eminence fractures with an avulsion of the bony avulsions of the ACL on the tibia and midsubstance ligament injuries. The treatment of bony avulsions is generally accepted. In complete midsubstance tears conservative treatment is insufficient, resulting in multiple giving way episodes and meniscal lesions. Controversy exists regarding the surgical treatment of complete midsubstance ruptures. Especially in younger patients with wide open physes, the risk of a growth disturbance due to transphyseal drilling has not been completely evaluated. In patients approaching physeal closure intraarticular ACL replacement using an autogenous bone-patellar tendon-bone graft has been shown to yield good short-term to mid-term results. There is a growing concern regarding the long-term outcome of ACL grafts with higher rerupture rates being suspected in children compared to adults. For these reasons more clinical and experimental data are needed in forthcoming studies.

Adult↗
PubMed1999

Genetically corrected autologous stem cells engraft, but host immune responses limit their utility in canine alpha-L-iduronidase deficiency.

Canine alpha-L-iduronidase (alpha-ID) deficiency, a model of the human storage disorder mucopolysaccharidosis type I (MPS I), is an ideal system in which to evaluate the clinical benefit of genetically corrected hematopoietic stem cells. We performed adoptive transfer of genetically corrected autologous hematopoietic cells in dogs with alpha-ID deficiency. Large volume marrow collections were performed on five alpha-ID-deficient dogs. Marrow mononuclear cells in long-term marrow cultures (LTMCs) were exposed on three occasions during 3 weeks of culture to retroviral vectors bearing the normal canine alpha-ID cDNA. Transduced LTMC cells from deficient dogs expressed enzymatically active alpha-ID at 10 to 200 times the levels seen in normal dogs. An average of 32% of LTMC-derived clonogenic hematopoietic cells were provirus positive by polymerase chain reaction and about half of these expressed alpha-ID. Approximately 10(7) autologous gene-modified LTMC cells/kg were infused into nonmyeloablated recipients. Proviral DNA was detected in up to 10% of individual marrow-derived hematopoietic colonies and in 0.01% to 1% of blood and marrow leukocytes at up to 2 to 3 years postinfusion. Despite good evidence for engraftment of provirally marked cells, neither alpha-ID enzyme nor alpha-ID transcripts were detected in any dog. We evaluated immune responses against alpha-ID and transduced cells. Humoral responses to alpha-ID and serum components of the culture media (fetal bovine and horse sera and bovine serum albumin) were identified by enzyme-linked immunosorbent assay. Cellular immune responses to autologous alpha-ID but not neo(r) transduced cells were demonstrated by lymphocyte proliferation assays. To abrogate potential immune phenomena, four affected dogs received posttransplant cyclosporine A. Whereas immune responses were dampened in these dogs, alpha-ID activity remained undetectable. In none of the dogs engrafted with genetically corrected cells was there evidence for clinical improvement. Our data suggest that, whereas the alpha-ID cDNA may be transferred and maintained in approximately 5% of hematopoietic progenitors, the potential of this approach appears limited by the levels of provirally derived enzyme that are expressed in vivo and by the host's response to cultured and transduced hematopoietic cells expressing foreign proteins.

Animals↗
PubMed1999

[Arthroscopy for diagnosis and therapy of early osteoarthritis of the hip].

Failure to conservative treatment in patients with less advanced radiographic signs of osteoarthritis of the hip (Danielsson grade 2-5) confronts with the decision of further treatment. Since radiographic imaging has not been proved very useful in demonstrating intraarticular structures and results of hip arthroscopies have been promising, arthroscopies have been performed in 17 hips from November 1997 to September 1998. Arthroscopic findings were exceeding preoperative imaging. In addition to cartilage degeneration, concomitant loose bodies, impinging osteophytes, degeneration of the labrum and synovial disease were found. Removal of loose bodies and osteophytes, partial resection of labral tears and partial synovectomy were performed. 1 month after arthroscopy (n = 15), mean Harris-Hip-Score was increased by 13 points und pain reduced by 39 % on average. 6 months after arthroscopy (n = 9), mean Harris-Hip-Score was increased by 14 points and pain reduced by 32 % on average. In addition to its therapeutic benefit, arthroscopy offers direct visualisation of the hip providing important information for the decision of further treatment.

Arthroscopy↗