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Biomedical subjects

J Stürup

Publications and source records attributed to J Stürup.

At least 19 recordsLinked to original sources

Blood perfusion and remodelling activity in canine tibial diaphysis after filling with a new bone cement compared to bone wax and poly(methyl methacrylate) cement.

Six dogs each had one tibia filled with standard poly(methyl methacrylate) (PMMA) bone cement and the contralateral tibia filled with a new methyl methacrylate-n-decyl methacrylate-isobornyl methacrylate (MMA-DMA-IBMA) bone cement (Boneloc) with lowered polymerization heat and monomer leakage. An additional six dogs each had one tibia filled with MMA-DMA-IBMA and the contralateral tibia filled with bone wax. There was a higher diaphyseal blood flow, measured with a microsphere technique, in the legs filled with MMA-DMA-IBMA than in those filled with PMMA. The wax-filled bones presented higher blood perfusion than those with MMA-DMA-IBMA. We found a tendency towards higher 99mtechnetium-labelled methylene diphosphonate (99mTcMDP) uptake, and autoradiograms revealed a tendency towards larger subperiosteal apposition and more blackening, both at the subperiosteal apposition and the cortex, in the bones filled with new bone cement in the first series, but in wax-filled bone in the second series. It is concluded that the new bone cement, compared to standard acrylic bone cement, seems to inhibit the vascular response and bone remodelling activity less, making earlier remodelling possible. However, the new bone cement still seems to inhibit bone blood perfusion compared to bone wax.

Animals↗

Effects of polymerization heat and monomers from acrylic cement on canine bone.

We investigated the effects of polymerization heat and toxicity of polymethylmetacrylate bone cement in the canine tibial diaphysis. Heat was studied by filling the tibias with either bone cement or bone wax contained in a monomer tight membrane pouch. Toxicity was studied by filling both tibias with cement, with the control side contained in the membrane pouch. Bone blood perfusion was measured by microsphere technic, and bone remodeling by 99mTc-methylene diphosphonate uptake and by histologic technique. In bone exposed to the combination of polymerization heat and monomer, both perfusion and remodeling were impaired. We did not find any effects of polymerization heat alone. We conclude that hot toxic chemicals from bone cement during polymerization may inhibit bone blood perfusion and remodeling, whereas heat alone seems to be of minor importance for the regenerative processes in cemented diaphyseal bone.

Animals↗

Improved cortical histology after cementation with a new MMA-DMA-IBMA bone cement: an animal study.

The histological response of bone to inert bone wax, conventional polymethylmethacrylate (PMMA), and a new formulation of bone cement, methylmethacrylate/n-decylmethacrylate/isobornylmethacrylate (MMA/DMA/IBMA) was investigated in canine tibial diaphysis. The new formulation of cement is characterized by a reduced exothermic temperature at curing and reduced leakage of chemicals to the adjacent bone. In comparison with bone wax, the MMA/DMA/IBMA bone cement did not differ significantly with respect to periosteal apposition and bone remodeling, although a tendency to inhibit the biological response was encountered. The MMA/DMA/IBMA was clearly superior to PMMA bone cement in respect to both bone necrosis and repair, as well as bone remodeling.

Animals↗

The effect on cortical bone of reaming and filling of canine tibial diaphysis with inert bone wax.

In canine studies the effect of intramedullary reaming on tubular bone was investigated in 4 dogs. Intramedullary reaming was further compared with reaming and intramedullary filling with bone wax in 6 dogs. Bone blood perfusion was measured by a microsphere technique and bone remodelling activity by 99mTc-MDP uptake. From histological sections bone necrosis and remodelling activity were estimated. The biological response increased with the surgical trauma. If the medullary cavity was only reamed, endosteal apposition was the predominant reaction. Obturation of the medullary cavity resulted in more vigorous subperiosteal and cortical reaction. It is concluded that the remodelling processes differ significantly between reamed bone and bone where the medullary cavity is reamed and blocked. Thus when testing bone cement the studies should include a control operation with obturation of the medullary canal in a way simulating bone cement.

Animals↗

Histological evaluation of cortical bone reaction to PMMA cement.

This study was designed to investigate histological changes in the tibia of adult mongrel dogs receiving PMMA bone cement in one tibial shaft and an inert filler, Bone wax, in the other. Sixteen dogs were used, 2 dogs were investigated at one week, 6 dogs at four weeks and 8 dogs at twelve weeks. It was shown in this study, that intramedullary implantation of PMMA bone cement leads to considerable impairment of bone remodelling. At each period of observation the index periosteal apposition/cortex thickness was lower on the cemented side; at 4 weeks an index of 0.42 (0.17-0.64) compared to 0.72 (0.42-0.91), and a 60-70 microns concentric fibrillar fibrous membrane was seen between cement and bone. On the Bone wax side few or no areas of fibrous tissue were detected at both 4 and 12 weeks; and when such tissue was present, islands of bone developing directly onto the wax was seen. The bone remodelling was impaired on the cemented side and limited to the outer half after 4 weeks.

Animals↗

Decreased blood perfusion in canine tibial diaphysis after filling with acrylic bone cement compared with inert bone wax.

Sixteen dogs had one tibia filled with acrylic PMMA bone cement and the opposite, control tibia filled with inert bone wax. After 1, 4, and 12 weeks, the blood perfusion in diaphyses was measured with Sc-46 labeled microspheres. The blood flow rates increased from 1 to 4 weeks and dropped to about the 1-week level after 12 weeks on both sides, with the acrylic side lower than the control side. On both sides, Disulphine Blue staining of the bones showed severe endosteal avascularity after 1 and 4 weeks and massive periosteal apposition after 4 and 12 weeks. The initial increase in blood flow is considered due to periosteal apposition, and the differences in blood flow rates are attributed to avascularity caused by the polymerization heat and toxicity of the acrylic cement.

Animals↗

Clinical results after revision and primary total hip arthroplasty.

Results after 184 primary and 227 revision total hip arthroplasties were compared with an emphasis on rates of failure leading to reoperation and intra- and postoperative complications and on the clinical outcome of the nonrevised arthroplasties in the two series. The failure rate was 7% (11 of 156) in the primary series, versus 27% (54 of 195) in the revision series. The rate of complications was substantially higher after revision, due to 16% (36 of 227) intraoperative fractures of the femoral shaft and 6% (14 of 227) postoperative dislocations. Clinical assessment of the nonrevised arthroplasties in the two series revealed no difference with regard to relief of pain. For patients with concomitant disabling conditions functional outcome was inferior after revision, but for patients without such conditions the functional results of the two series were equal. The favorable clinical results of the nonrevised arthroplasties in the revision series must be seen in relation to the very high rate of failure leading to reoperation.

Adult↗

Traumatic amputation of the upper limb: the use of body-powered prostheses and employment consequences.

Forty three patients with unilateral traumatic amputations were reviewed as to the use of prostheses and employment consequences of the amputation. Seventeen of 19 below-elbow amputees, and 12 of 24 above-elbow amputees used their prostheses. Non-users compared to users of prostheses were characterized by: 1) Higher level of amputation 2) Non-dominant arm amputation and 3) Younger age at the time of amputation. However non-users usually did well on the labour market for various reasons.

Adult↗

Screw fixation in the femoral head. Pull-out tests in cadavers.

The aim of our study was to determine whether a subchondral or a capital position of the thread of the gliding screw provided the best fixation. A pull-out test was performed on pairs of femoral neck cadaver specimens. The capital position of the thread provided the best fixation in all the pairs. A correlation was found between bone mineral content of the femoral heads and the holding power of the screws in both positions.

Aged↗

Resection of the lateral end of the clavicle following osteolysis, with emphasis on non-traumatic osteolysis of the acromial end of the clavicle in athletes.

Preoperative radiographs of 38 patients who had undergone resection of the lateral end of the clavicle were reviewed. Seven cases of osteolysis of the lateral end of the clavicle were found, of which four followed severe injury of the shoulder girdle. Three of the cases were young male athletes, with nontraumatic osteolysis. One additional patient with this disorder, in whom resection has not yet been performed, was also included. All four had practised weightlifting and benchpressing as part of their training. Hence, a feasible explanation for the osteolytic process seems to be repeated microfractures due to stresses imposed by these activities. Several conservative regimens provided only temporary relief. After resection, the symptoms ceased and the patients were able to return to competitive sport. With the increasing interest in bodybuilding, non-traumatic osteolysis of the acromial end of the clavicle should be borne in mind in cases of pain in the shoulder in athletes.

Adult↗

Flucloxacillin in chronic leg ulcers. Penetration of flucloxacillin into chronic leg ulcer exudate and the effect on the bacteria.

The penetration of flucloxacillin into ulcer exudate was investigated in six patients with chronic leg ulcers. The flucloxacillin dosage used was 1 g orally three times daily for three days, and the serum and exudate concentrations were measured repeatedly during a 10 h-period following the first and the seventh dose. All the ulcers were contaminated with (S. aureus) Staphylococcus aureus either in pure culture (three ulcers) or in culture mixed with Gram-negative bacteria (three ulcers). Bacterial counting in the ulcers was performed twice before and twice during the antibiotic treatment. The flucloxacillin concentrations measured in the ulcer exudate were found to be lower than the corresponding serum concentrations. However, the exudate concentrations were found to be above the minimum inhibitory concentration (MIC) for the contaminating S. aureus during an average of 7 h after each dose, and the number of S. aureus during the treatment period was reduced to less than 0.01% of the initial number. The Gram-negative bacteria were not susceptible to flucloxacillin. The number of these bacteria decreased before flucloxacillin treatment but increased again during treatment, probably owing to the changed conditions in the ulcers following the marked decrease in the number of S. aureus.

Aged↗

Epidemiology of knee injuries in children.

We analyzed 91 consecutive metaphyseal fractures, physeal injuries, and ligament ruptures in children aged 0-14 years. In the younger children, metaphyseal fractures dominated, whereas teenager had ligament rupture associated with low-energy trauma and physeal injury with high-energy trauma.

Adolescent↗

Abnormal knee mobility and meniscal injury.

Stress radiography for anteroposterior mobility of the knees was performed in 17 patients who had undergone medical meniscectomy and 10 patients who had undergone lateral meniscectomy. Sixteen of the patients were also tested for valgus-varus mobility. An increase in varus mobility following medical meniscectomy was primarily attributed to compression of the medical compartment space. No increase in anteroposterior mobility was found in the knees that had undergone meniscectomy compared with the uninjured contralateral knees. Anterior and total anteroposterior mobility were bilaterally greater in patients with medial meniscectomy compared with lateral meniscectomy. Furthermore, for the patients with medial meniscectomies anterior as well as total mobility were bilaterally greater than values obtained in 28 normal knees. We conclude that idiopathic anteroposterior hypermobility seems to predispose to injury of the medical meniscus. Perhaps individuals with generalized joint laxity should be warned against participating in contact sports.

Adult↗

Retroperitoneal perforation of duodenal ulcer.

Retroperitoneal perforation of a duodenal ulcer occurred in a 51 year female. The patient was seriously ill, but recovered after laparotomy with drainage of an abscess, closure of the duodenum and a gastro-jejunal anastomosis. The diagnosis is difficult to establish because of the anatomical relationships.

Abscess↗