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Biomedical subjects

D Kohn

Publications and source records attributed to D Kohn.

230 records · Page 13Linked to original sources
PubMedDate not supplied

[Stress relief of the hip joint by the Thomas splint].

The Thomas Splint is mainly administered to relieve weight from the hip joint. Theoretically the leg is bypassed by transmitting the body weight directly from the pelvis to the floor.--Load transmission via a Thomas Splint was measured with an orthosis strain gauged at the ischial interface area and at the foot plate. The results show, that about one half of the weight will bypass the joint through the orthosis. The Thomas splint ist unsuitable in cases when complete weight relief from the hip joint is necessary.--These results did not depend on whether the floor was flat or ascending, or whether stairs were climbed. The lateral bar never carried more then 25% of the force transmitted.

Adult↗
PubMedDate not supplied

[Vascular injuries in acetabular implantation and acetabular replacement surgery--case report, literature review and anatomical study].

Severe intraoperative bleeding during revision hip arthroplasty in one of our patients was the motive of the work reported here. A review of the literature and an anatomical cadaver study were carried out. The distance between the acetabular fossa and the intrapelvic blood vessels was measured in 15 specimens. The risk for the obturator artery is particularly high. The distance between this vessel and the acetabulum is 2 mm (1-5 mm) only. An account of previous complications and the vascular anatomy as pointed out in our report may help to prevent severe bleeding complications in hip surgery.

Acetabulum↗
PubMedDate not supplied

[Prosthesis for tumor of the hip joint (indications and results)].

Between 1972 and 1982 34 tumour prostheses (23 total replacements, 11 semitotal replacements) of various designs were implanted at the State Orthopedic Clinic in Munich-Harlaching and at the University Orthopedic Clinic in Grosshadern. The indications were primary and secondary malignant tumours, potentially malignant tumours, peritrochanteric pseudarthroses, and loosening of prostheses where bone conditions were poor. Since 1977 only the "Harlaching" femoral tumour prosthesis, a locally developed model, has been used. Its distinguishing feature is the modular or kit principle, which renders it possible to adapt the prosthesis and define its length accurately during surgery. On the basis of 13 long-term observations, in some cases extending over 8 years, it was established that this tumour prosthesis need not be regarded as merely a palliative intervention (this applies also to younger patients with a longer life expectancy); the slight and transitory complications and the relatively good long-term functional results are encouraging.

Bone Neoplasms↗
PubMedDate not supplied

[An in vitro model for producing femoral fractures and for the study of primary stability of cerclage].

PURPOSE: Intraoperative femoral fracture is a well recognized intraoperative complication of cementless total hip arthroplasty (THA). This study was designed to establish an in-vitro model for initiation of fractures of the femur in cementless THA and to assess the effect of fracture fixation by cerclage wiring using steel wire (Protasul). METHODS: Ten human femur specimens were studied. Longitudinal cracks were created by pressing a well fixed conical stem deeper into the femur in a material testing machine. RESULTS: The force necessary to propagate a longitudinal crack in the femur was 1915 N to 9288 N (median 6531 N). This forces are according to 3 to 15 times (median 11 times) body weight. There was no difference of force between left and right femurs from the same individual (U-test). The femoral cortex fractured in 5 cases ventrally, in 6 cases medially and in 1 case laterally. After monofile cerclage wire application the force required to press prosthesis 5 mm deeper into the medullary canal was 0.3 to 2.7 times body weight. After monofile cerclage wire application pressing in the prosthesis 30 mm needed 1.8 to 8.1 times body weight. CONCLUSIONS: During insertion of a conical stem the orthopaedic surgeon should look for fractures of the medial cortex of the femur which is the most frequent location for fractures. This in-vitro model provides a reproductable method for the initiation and propagation of longitudinal femoral fractures in press-fit noncemented THA system and to assess the effect of fracture fixation in the form of cerclage wiring.

Adult↗
PubMedDate not supplied

Epidural vs. intramuscular oxymorphone analgesia after thoracotomy in dogs.

Oxymorphone was administered epidurally (0.1 mg/kg) or intramuscularly (IM) (0.2 mg/kg) to 16 dogs undergoing thoracotomy, to compare the analgesic effectiveness. Heart rate, respiratory rate, systolic and diastolic blood pressure, and pain score were measured hourly. Arterial blood gases were measured at hour 1. A single dose of oxymorphone injected epidurally provided analgesia for up to 10 hours, whereas the IM route provided a comparable effect for less than 2 hours. There were statistically significant increases in heart rate, and systolic and diastolic blood pressures at hour 2 in the dogs treated IM over the dogs treated epidurally. We conclude that epidurally administered oxymorphone is highly effective in alleviating pain after thoracotomy in dogs and provides longer lasting analgesia than the IM route.

Analgesia, Epidural↗
PubMedDate not supplied

Primary stability of press-fit-implanted osteochondral grafts. Influence of graft size, repeated insertion, and harvesting technique.

The aim of this study was to evaluate the fixation strength of press-fit-implanted osteochondral grafts with respect to graft size (length and diameter), the effect of repeated insertion after pullout, and harvesting technique. Experiments were performed using the Osteochondral Autograft Transfer System on porcine femoral condyles. Failure loads of 10-mm-long grafts (mean, 47 N) were significantly lower than failure loads of 15-mm-long grafts (mean, 93 N) and 20-mm-long grafts (mean, 110 N) (all grafts, 11 mm in diameter). Reinsertion of the 15-mm-long grafts after initial pullout resulted in a significant reduction of failure loads (mean, 93 N versus 44 N). Failure loads of 8-mm-diameter grafts (mean, 41 N) were significantly lower than those of 11-mm-diameter grafts (mean, 92 N) (all 15 mm long). Levering of the tubular chisel during graft harvest significantly decreased press-fit stability as compared with simple turning of the chisel (mean, 32 N versus 52 N) (8-mm diameter and 15-mm length). These results suggest that primary fixation strength of press-fit-inserted osteochondral grafts depends on the size of the grafts and that repeated pullout and reinsertion of grafts as well as a nonoptimal harvesting technique (levering) will reduce primary stability.

Animals↗
PubMedDate not supplied

Reconstruction of the anterior cruciate ligament. A new positioning and fixation technique.

A new technique for ACL reconstruction is presented. The middle third of the patellar tendon is anchored to the inner surface of the lateral femoral condyle under direct visual control. The transplant is fixed tibially beneath a bone block removed from the ventral tibial head. Thirty-three patients were evaluated preoperatively and 27 months (range, 24 to 30 months) postoperatively. The mean preoperative function score (Lysholm scoring scale) was 72 +/- 14 points; the mean postoperative score was 84 +/- 13 points. The Lachman test was positive for all patients preoperatively, but the test results in the postoperative follow-up examination were negative--1+ in 31 knees and 2+ in 2 knees. All 33 knees elicited a definite "hard" end point. The postoperative KT-1000 measurement for anterior tibial displacement showed no significant difference between the operated versus the unoperated knee. Before their knee injury all patients had been engaged in sports. At the follow-up examination, 13 patients had made a full return to their former sports activities, 13 were restricted in their sports activities, and 7 patients no longer participated in sports.

Adult↗
PubMedDate not supplied

Primary stability of interference screw fixation. Influence of screw diameter and insertion torque.

Interference screw fixation is frequently used in anterior cruciate ligament reconstruction with the bone-patellar tendon-bone graft. There have been no data available about the influence of screw diameter and insertion torque on primary stability. We designed a cadaveric study using paired knees to analyze the comparative effectiveness of 20-mm long screws of different diameters (9 mm versus 7 mm) and the significance of torque during screw insertion. Testing to failure was performed in a tensiometer with a crosshead speed of 200 mm/min. After slippage of a bone peg in the 7-mm screw specimens, the experiment was repeated in each specimen with a 9-mm screw fixation. Maximum tensile force was greater at the femoral insertion than at the tibial site. Results of refixations with 9-mm screws were only slightly inferior to the original 9-mm screw fixation specimens. Our results further showed that the torque can be used as a predictor of the stability of the bone block but cannot be used as an indicator for the strength of the reconstruction. The 7-mm screws are not recommended for tibial fixation. Failed 7-mm screw fixations can be replaced by 9-mm screws and refixations were successful in our study model.

Adult↗
PubMedDate not supplied

Sports injuries in team handball. A one-year prospective study of sixteen men's senior teams of a superior nonprofessional level.

One hundred eighty-six players of 16 teams in 2 male team handball senior divisions were observed prospectively for 1 season to study the injury incidence in relation to exposure in games and practices. Ninety-one injuries were recorded. Injury incidence was evaluated at 2.5 injuries per 1000 player-hours, with a significantly higher incidence in game injuries (14.3 injuries per 1000 game-hours) compared with practice injuries (0.6 injuries per 1000 practice-hours). Practice injury incidence was higher in the lower performance level group, and game injury incidence was higher in the high-level group. The upper extremity was involved in 37% of the injuries, and the lower extremity in 54%. The knee was the most commonly injured joint, followed by the finger, ankle, and shoulder. Knee injuries were the most severe injuries, and they were more frequent in high-level players. There was an increase in the severity of injury with respect to performance level. The injury mechanism revealed a high number of offensive injuries, one-third of them occurring during a counterattack. The injury pattern showed certain variations with respect to player position and performance level. Prophylactic equipment was used by a majority of players at the higher performance level.

Adult↗
PubMedDate not supplied

America speaks. Was anyone listening?

Town meetings are a uniquely American political device intended to allow citizens to have a voice in the course of the local or even national policymaking process. On January 14, 1992, Democratic members of the U.S. House of Representatives conducted 140 such meetings to discuss health care reform. While the discussions ranged from the ridiculous to the sublime, Americans made it clear that they are fed up with a current system that they believe costs too much and provides too little. But a key question remains: Who, if anyone, was listening? House Democrats appear determined to avoid specifics and to pin President Bush with an "anti-health" label. The strategy is a risky one; a riled up populace could well turn against those who convinced them to be concerned in the first place.

Attitude to Health↗
PubMedDate not supplied

Is preoperative fasting necessary?

The effects of fasting and of histamine (H2) antagonists on gastric volume and acidity were studied in 56 baboons undergoing various surgical procedures under general anesthesia and randomly allocated into 4 groups; group A--fasted for 14 hours; group B--given 100-120 ml of water 3 hours before surgery; groups C and D--also given 100-120 ml of water 3 hours before surgery; in addition, the former received cimetidine 10 mg/kg IM and the latter ranitidine 1.5 mg/kg IM 30-40 minutes before anesthesia. There were no significant differences between groups A and B with respect to the gastric volume and pH. Both ranitidine and cimetidine significantly (P < 0.02) reduced gastric volume and increased gastric pH. Thus, prolonged withholding of oral fluids does not reduce the gastric volume or increase gastric pH. H2-antagonists are effective in reducing both gastric residual volume and pH.

Animals↗
PubMedDate not supplied

[Ultrastructural findings of the muscles around lip clefts].

Our electron microscopic observations show alterations of the muscles near the cleft margins confirming the theory resulting from light microscopic and immunohistochemical findings that the myogenic structures surrounding cleft margins are inferior tissue that is capable neither of regeneration nor of normal function. The clinical implication derived from these observations is that the tissue in the vicinity of the clefts should be generously excised when doing cheiloplasties.

Cleft Lip↗