Einar Sudmann

Indomethacin-induced inhibition of haversian remodelling in rabbits.

The effect of indomethacin on haversian remodelling in the radius was studied in 16 rabbits. An osteotomy and a saw-cut almost through the bone were made in the middle and distal parts of the right radius, respectively. In order to obtain biological osteosynthesis in the osteotomy and the saw-cut the rabbits were not treated in any way during the following 3 weeks. They were then given either indomethacin or placebo suspensions per os, 10 mg/kg/day for 2 weeks, followed by 5 mg/kg/day for 4 weeks. The extent of haversian remodelling was estimated by calcein and oxytetracycline fluorochrome labels given at the start of the indomethacin treatment and 3 weeks later, respectively. After 2 weeks of indomethacin treatment (10 mg/kg/day) the indomethacin plasma levels were about 0.18 microgram/ml 24 hours after the last dose. Indomethacin treatment significantly (2P less than 0.019) inhibited haversian remodelling as estimated by fluorochrome labelling.

Fracture healing in rats inhibited by locally administered indomethacin

We studied the inhibitory effect of indomethacin on fracture healing in 135 young, male rats after oral administration compared with local application into the fracture. A closed mid-diaphyseal fracture of the left femur was performed in all the rats. The fractures were not immobilized. In one experiment, half of the animals received indomethacin via a stomach tube (2 mg/kg/day) for 10 days; the controls received only the vehicle. In another experiment, 0.5 mg of indomethacin, contained in a bioerodible polyorthoester gel, was injected into the fracture area in half the rats; in the controls, only the gel was injected. In both experiments, random animals were killed on Days 0, 5, 10, and 20. As assessed by radiographs and manual testing, the same inhibition of fracture healing was found regardless of whether indomethacin was given orally or locally. However, the amount of indomethacin that was applied locally was only one fourth of the total dose given orally; no indomethacin was detected in the serum.

Biocompatibility and effect on osteogenesis of poly(ortho ester) compared to poly(DL-lactic acid)

Implantation of demineralized bone induces new bone formation by the action of contained growth factors, of which bone morphogenetic proteins are of prime importance. A biodegradable polymer may be used as a carrier for demineralized bone particles or recombinant bone growth factors to prevent displacement of the implant, preserve its volume and shape, and assure sustained release of the incorporated active components. A polymer for this use should be biocompatible and completely absorbed without interfering with the osteogenesis. We investigated the host-tissue response and effect on demineralized bone-induced bone formation by two biodegradable polymers, a poly(ortho ester) and an amorphous low-molecular poly(DL-lactic acid). Both polymers had a plastic consistency, could easily be molded, and adhered well to the demineralized bone particles. Demineralized bone particles were implanted alone and in combination with each of the polymers in the abdominal muscles of 45 male Wistar rats. Four weeks after the operation the implants were recovered and subjected to (85)Sr uptake analysis to quantify bone formation and histologic examination. The poly(ortho ester) provoked little inflammation; it was largely absorbed by 4 weeks, and no qualitative or quantitative effect on bone formation was found. The poly(DL-lactic acid) provoked a chronic inflammation with multinuclear giant cells, macrophages with engulfed material, and proliferating fibroblasts; part of the material was still present, and the bone formation was inhibited.

Histologically verified bone wax (beeswax) granuloma after median sternotomy in 17 of 18 autopsy cases

Aim: To evaluate the sternum from ordinary or forensic autopsy cases with a midline sternal cutaneous scar macro‐ and microscopically and using computed tomography (CT) to detect if the haemostatic bone sealant bone wax (beeswax) had been applied after median sternotomy and if the bone wax had elicited inflammation. Methods: During a 3‐year period, the sterna of 18 consecutive cadavers (15 ordinary autopsies, 3 forensic) who prior to death had undergone surgery with median sternotomy were examined macro‐ and microscopically and with CT. In addition, one virgin sternum was smeared with bone wax at the upper half after bench sternotomy, sutured and examined with CT. Unused bone wax was examined with CT for attenuation measurements. Results: Macroscopically, bone wax was seen in 17 of 18 sterna. Acute inflammation was found in one, chronic inflammation and foreign body multinucleated giant cells were seen around the bone wax in 17 sterna. No inflammation was found in one. CT could only detect foci in the operated sterna with attenuation values from −45 to +20 Hounsfield units (HU) and values about −80 HU were found in the virgin sternum. Unused bone wax measured about −100 HU. Conclusions: Bone wax is non‐resorbable and induces chronic inflammation in the operated sternum up to 10 years after application. Measurement of Hounsfield units with CT of the operated sterna could not verify bone wax granuloma.

The Charnley Versus the Christiansen Total Hip Arthroplasty: A Comparative Clinical Study

Charnley total hip arthroplasties (THA) and Christiansen THA were carried out in two concurrent groups of patients, consisting of 113 hips in 87 patients and 90 hips in 81 patients respectively. The mean age of the patients was about 65 years, two thirds had idiopathic arthrosis, and only two had rheumatic hip disease. The two groups of patients were similar with regard to sex, age, weight, etiology of arthrosis, and standard laboratory tests, but different with regard to the surgeons who operated on them. Postoperative films showed that the stems of the prostheses were in the neutral and the varus position in the Christiansen group, and in the valgus, neutral and varus position in the Charnley group. Neither group had any deaths, or deep infections in the postoperative period. Only minor postoperative complications were noted. At follow-up, 5-8 years later, the failure (revision) rate of Charnley THA to Christiansen THA was 1 to 7.7 and 1 Charnley cup was revised as against 19 Christiansen cups. The methodological weaknesses in the comparative clinical trial did not explain the inferior long-term results of the Christiansen THA.

Bone induction by composites of bioresorbable carriers and demineralized bone in rats: A comparative study of fibrin-collagen paste, fibrin sealant, and polyorthoester with gentamicin

Host tissue response and heterotopic osteoinduction by composites of demineralized bone matrix and three different substances used as bioresorbable carriers implanted in the abdominal muscles were evaluated by strontium 85 uptake and histology 4 weeks postoperatively in 60 male Wistar rats. Both fibrin-collagen paste and fibrin sealant inhibited bone induction and produced a chronic inflammation; part of the fibrin-collagen paste was still present at 4 weeks. Polyorthoester with gentamicin was almost completely absorbed, induced minimal tissue reaction, and did not inhibit osteoinduction.

Wear of the acetabular socket Comparison of polyacetal and polyethylene

Frictional characteristics of polyacetal (Delrin) sockets and of ultra-high molecular weight polyethylene sockets retrieved in revision after aseptic loosening were compared with measurements of friction in new sockets. Friction in retrieved polyacetal sockets was twice as great as in retrieved polyethylene sockets. We also found that frictional characteristics of polyacetal changed as the material aged in vivo. In contrast, friction in polyethylene sockets remained fairly constant, even though most of them contained bone-cement particles. Friction in polyacetal sockets may be important for the relatively high incidence of socket loosening of the Christiansen prosthesis. Measurements of wear of the polyacetal sockets showed a mean annual dimensional change of 240 mm3, four times greater than that reported for the Charnley polyethylene acetabular prosthesis.

Bone induction by composite of bioerodible polyorthoester and demineralized bone matrix in rats

A composite of a local, sustained, drug-release system, Alzamer bioerodible polyorthoester, and demineralized bone-matrix (DBM) particles implanted in the abdominal muscle of 89 Wistar rats induced cartilage and bone formation at the same rate as DBM when evaluated histologically and by 85Sr uptake. The composite implant was technically easier to use than DBM alone.

Effect of local hemostatics on platelet aggregation

The platelets play an important role in the normal hemostasis, and it is known that both natural and synthetic macromolecules may induce platelet activation and aggregation. Thus, the purpose of the present study was to investigate the platelet aggregating effect of five different local hemostatics. Platelet aggregation was assessed by aggregometry. Unwoven fleece of bovine collagen polymer in fibrillar form induced aggregation in combination with small amounts of platelet agonists; ADP and adrenaline. Ordinary, nonabsorbable bone wax also induced aggregation in combination with the agonists, but larger concentrations of agonists were needed. Bioerodible polyorthoester with physical properties such as bone wax, oxidized cellulose and gelatin sponge did not promote platelet aggregation.

Pelvic joint fusions in patients with chronic pelvic girdle pain: a 23-year follow-up

PurposeFusion of the sacroiliac joints (SIJ) has been a treatment option for patients with severe pelvic girdle pain (PGP). The primary aims were to evaluate the long-term outcomes in patients who underwent SIJ fusion and to compare 1-year outcomes with long-term outcomes. The secondary aim was to compare patients who underwent SIJ fusion with a comparable group who did not.MethodsThis study includes fifty patients that underwent SIJ fusion between 1977 and 1998. Function (the Oswestry disability index; ODI), pain intensity (visual analogue scale; VAS) and health-related quality of life (SF-36) were determined according to a patient-reported questionnaire. The questionnaire scores were compared with previously recorded 1-year outcomes and with questionnaire scores from a group of 28 patients who did not undergo SIJ fusion.ResultsThe patients who underwent SIJ fusion reported a mean ODI of 33 (95xa0% CI 24–42) and a mean VAS score of 54 (95xa0% CI 46–63) 23xa0years (range 19–34) after surgery. Regarding quality of life, the patients reported reduced physical function, but mental health was not affected in the same manner. The patients with successful 1-year outcomes (48xa0%) retained significantly improved function and reduced pain levels compared with the subgroup of patients with unsuccessful 1-year outcomes (28xa0%). The patients who underwent surgery did not differ from the non-surgery group in any outcome at the long-term follow-up.ConclusionsPatients treated with SIJ fusion had moderate disability and pain 23xa0years after surgery, and the 1-year outcomes were sustained 23xa0years after surgery. Although many fused patients reported good outcome, this group did not differ from the comparable non-surgical group.