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Biomedical subjects

S K Bulstra

Publications and source records attributed to S K Bulstra.

At least 19 recordsLinked to original sources
PubMed2006

[Reduce the mortality due to femur fractures via an integrated approach to the comorbidity].

Preliminary studies show that there is an annual increase in the number of operations for femur fractures in The Netherlands and that this increase can be ascribed totally to the increasing age of the population, even though the risk of falling has not increased. Although the hospital mortality in this category of patients has decreased, mainly as the result of a shortened hospital stay, the long-term mortality does not seem to have decreased in comparison to earlier analyses. The conclusion could well be that we in The Netherlands must be able, in the future, to reduce the long-term mortality by means of a better integrated approach to care, as has already been described in other studies.

Accidental Falls↗
PubMed1999

Effectiveness of physiotherapy after meniscectomy.

To evaluate the effect of physiotherapy after partial arthroscopic meniscectomy, we performed a prospective, randomised and partially blinded study. This pilot study was performed from October 1996 to June 1997. The control group received the standard treatment, consisting of verbal and written advice and exercises. The physiotherapy group performed exercises according to a dynamic protocol under the supervision of a physiotherapist. During a 3-week period, nine treatment sessions were given of 30 min each. Twenty patients, who had undergone arthroscopic meniscectomy without any other pathology of the knee, were randomised into two groups of ten patients each. The effects of therapy were evaluated by a blinded observer. We measured the distance and height of one-leg jumps (hops), the VAS pain scale, the Tegner and Lysholm scores and the SARS/FORS score. Recovery and satisfaction with the treatment were also evaluated. The effect measurements were performed at 7 (T1), 14 (T2), 21 (T3) and 28 days (T4) following surgery. Statistical analysis was performed with the Student's t-test. The physiotherapy group showed significantly better results than the control group regarding the SARS score, the hop test and the distance jumps. Moreover, the measurements showed clear progression in favour of the physiotherapy group. In conclusion, exercising under the supervision of a physiotherapist led to high patient satisfaction and good functional rehabilitation after partial arthroscopic meniscectomy.

Adult↗
PubMed1999

Osteogenic activity of OP-1 bone morphogenetic protein (BMP-7) in a human fibular defect.

We performed a prospective, randomised double-blind study in 24 patients undergoing high tibial osteotomy to evaluate the effectiveness of human recombinant osteogenic protein (OP-1) on a collagen type-I carrier in a critically-sized fibular defect. The study had two phases, each evaluated by clinical, radiological and DEXA methods during the first postoperative year. The first concerned the validation of the model of the fibular defect, using positive (demineralised bone) and negative (untreated) controls. The second phase concerned the osteogenic potential of OP-1 on collagen type-I v collagen type-I alone. The results of the first phase established the critically-sized nature of the defect. In the untreated group no bony changes were observed while, in the demineralised bone group, formation of new bone was visible from six weeks onwards. The results of the second phase showed no significant formation of new bone in the presence of collagen alone, while in the OP-1 group, all patients except one showed formation of new bone from six weeks onwards. This proved the osteogenic activity of OP-1 in a validated critically-sized human defect.

Adult↗
PubMed1998

[One hundred years of orthopedics in the Netherlands. VII. biomaterials].

The use of biomaterials in orthopaedics is becoming increasingly important. They are widely used in artificial joints, as bone replacement material and as resorbable material. Also (recombinant) bone morphogenetic proteins are used. Classification of biomaterials is based on composition (animal or human tissue, metals, polymers, ceramics or composites) or on biological reactions after implantation (bio-inert, bio-tolerant or bio-active). Depending on location and function biomaterials have to meet requirements with respect to durability (artificial joints), fixation (total hip prosthesis), flexibility (artificial ligaments), solubility (suture wire) and stiffness (plates and screws). The development of biomaterials is in full swing, focussing on the decrease of wear and the increase of durable fixation of artificial joints, and the induction of cells to form bone and cartilage tissue.

Biocompatible Materials↗
PubMed1998

The polymer Polyactive as a bone-filling substance: an experimental study in rabbits.

The biocompatible, osteoconductive and resorbable polymer Polyactive (PA) was investigated for its performance as a bone-graft substitute. The model consisted of a 4 mm borehole, 1.5 cm distal of the major trochanter in both femurs of a rabbit, of which one was filled with a cylinder of porous PA. The other was left untreated. PA70/30 and PA60/40 were investigated, both before and after being incubated with allogenic bone marrow. Analyses were performed after 4, 8, 26 and 52 weeks and comprised dual energy X-ray absorptiometry (DXA) and image analysis of histological sections. DXA revealed an increased bone mineral density in the filled defects compared to the controls, both at the defect and immediately proximal and distal of the defect. Histology showed that gap-bridging had occurred within 8 weeks, with 80%-90% of the pores of PA70/30 and PA60/40 occupied by new bone, and an intimate bone-PA contact. PA70/30 seemed to be more suitable compared to PA60/40, in that the highest amount of bone was formed within the shortest period of time. Incubation of PA with allogenic bone marrow resulted in inflammatory reactions at the sites of implantation, which delayed bone growth, but did not prevent it. It was concluded that PA70/30 and PA60/40 are suitable bone-graft substitutes.

Journal Article↗
PubMed1998

Quantitative histological analysis of bony ingrowth within the biomaterial Polyactive implanted in different bone locations: an experimental study in rabbits.

The quantity of bone formed in cylinders of a newly developed erodible copolymer, Polyactive (PA60/40) was examined. PA60/40 was implanted in three different bone locations in the rabbit: in the cortex, in bone marrow and in trabecular subchondral bone. Bony ingrowth was assessed after 4, 8, 26 and 52 w after the operation and investigated by histology and image analysis. The ingrowth of bone was observed in PA60/40 placed in the cortex from 4 w onwards. After 8 w, more than 90% of the pores of the biomaterial were filled with dense bone. In bone marrow, initially some bone formation was seen. After 26 w, all newly formed bone was resorbed. Subchondral bone formation was less than in the cortex of the femur, but somewhat comparable to the amount of bone found in healthy trabecular bone. Bone formation appeared not to be affected by the degradation of the biomaterial. It was concluded that Polyactive is a suitable bone graft substitute. Bone formation within PA60/40 is site-dependent and this follows Wolff 's law.

Journal Article↗
PubMed1998

A novel method to examine the phenotype of chondrocytes.

Tissue engineering of articular cartilage in order to restore the function of degenerated, diarthrodial joints is currently widely under investigation. The results obtained thus far indicate that proper control of the differentiation of the cells used for this purpose is essential to produce and maintain a hyaline-like matrix. In this study, a procedure is described by which differentiation of chondrocytes in vitro and ex vivo can be studied. The method involves quantitative assessment of mRNA for different collagens, which are markers for differentiation of chondrocytes, by competitive PCR. In a culture system employing human osteoarthritic chondrocytes, mRNAs for the alpha1-chains of collagen types I, II and X are quantified. The procedure is fast, specific and sensitive. However, several controls should be included to ascertain the reliability of the assessment.

Journal Article↗
PubMed1998

Clinical and pathological changes in the knee after accidental chlorhexidine irrigation during arthroscopy. Case reports and review of the literature.

We describe six knees in five patients, referred to us after accidental irrigation with chlorhexidine 1% in aqueous solution during arthroscopy. All six knees developed persisting pain, swelling and crepitus with loss of range of movement. Radiographs showed loss of joint space in all three compartments due to extensive chondrolysis, with many loose bodies and synovitis. Histological examination showed partial necrosis of the cartilage, with slight non-specific inflammation and fibrosis of synovial specimens. Care is needed in checking irrigation fluids, and these should have a distinctive colour.

Adult↗
PubMed1997

Long-term results of rib perichondrial grafts for repair of cartilage defects in the human knee.

Eighty-eight patients with articular cartilage defects in the knee were treated by perichondrial arthroplasty between 1986 and 1992. An autogenous strip of costal perichondrium was fixed in place with fibrin glue, followed by immobilisation, continuous passive motion, and partial weightbearing. The results were evaluated using the Hospital for Special Surgery Score for knee function, radiographs, arthroscopy and the patient's subjective opinion. The results after a mean follow-up of 52 months were good in 38%, fair in 8% and poor in 55%. Previous drilling or shaving of a defect, concomitant osteoarthritis, older age and a long history of complaints proved to be contraindications. Good results were seen in 91% of isolated defects. Perichondrial arthroplasty can be beneficial in the repair of cartilage defects. It will reduce symptoms in carefully selected cases, and avoid more extensive operations for osteoarthritis.

Adolescent↗
PubMed1996

Femoral canal occlusion in total hip replacement using a resorbable and flexible cement restrictor.

We have investigated the use of a conically-shaped cement plug made of Polyactive (PA), a biodegradable copolymer. The flexibility and hydrogel properties were thought to facilitate occlusion of the femoral canal even when it was oval or irregular in shape. The function of the plug was first compared with that of the Thackray polyethylene model in 16 artificial plastic femora. The maximum intramedullary pressure achieved during cementing was ten times higher with the biodegradable model. Migration or leakage of cement did not occur when the diameter of the femoral canal was equal to or smaller than the diameter of the plug. We also showed that the biodegradable properties of this implant were such that it did not require removal during revision. The new plug was tested in a pilot clinical trial. At two years only two out of 21 patients had evidence of migration or leakage of cement, probably due to a mismatch in the size of plug and femoral canal. There were no local changes in the femur.

Biocompatible Materials↗
PubMed1994

The effect in vitro of irrigating solutions on intact rat articular cartilage.

Rat patellae were preincubated with culture medium M199 for one hour and then with either fresh culture medium or Ringer's solution, Ringer lactate, Ringer glucose, normal saline or Betadine for another hour. The rate of proteoglycan synthesis in the articular cartilage was then measured by uptake of 35SO4 for the next 16 hours. Cartilage metabolism was inhibited by all of the solutions even after a recovery time of 16 hours. The inhibition was by 5% for Ringer's solution, 10% for Ringer glucose (p < 0.01), 20% for saline and Ringer lactate (p < 0.001) and 55% for Betadine (p < 0.001). Ringer's solution is therefore the best choice for joint irrigation during arthroscopy or other procedures.

Animals↗
PubMed1993

Thionin staining of paraffin and plastic embedded sections of cartilage.

The usefulness of thionin for staining cartilage sections embedded in glycol methacrylate (GMA) and the effect of decalcification on cartilage sections embedded in paraffin and GMA were assessed. Short decalcification periods using 5% formic acid or 10% EDTA did not influence the staining properties or the morphology of cartilage matrix and chondrocytes. The standard stain safranin O-fast green for differential staining of cartilage was used as control in these experiments. Prolonged exposure of safranin O stained sections to fast green resulted in disappearance of the safranin O stained matrix, thereby hampering the quantitative measurement of negatively charged glycosaminoglycans (GAG). Thionin stained evenly throughout all cartilage layers, independent of the staining times. In contrast to safranin O, thionin did not show metachromasia in nondehydrated cartilage sections, which made it more suitable for assessing cartilage quality in GMA embedded cartilage. To evaluate the selectivity of thionin staining in cartilage, chondroitinase ABC and trypsin digestions were carried out. Thionin staining was prevented by these enzymes in the territorial matrix, representing the interlacunar network and the chondrocyte capsule. Staining with thionin of the interterritorial matrix was only slightly reduced, possibly representing keratan sulfate and hyaluronic acid in cartilage of elderly patients. Comparison of thionin stained GMA embedded cartilage with safranin O stained paraffin embedded sections showed significant similarity in optical densitometry, indicative of the specificity of thionin bound to negatively charged GAG in cartilage. In GMA embedded cartilage morphology was relatively intact compared to paraffin embedded sections due to less shrinkage of chondrocytes and the interlacunar network.

Aged↗
PubMed1992

The reliability of the Mankin score for osteoarthritis.

For the histopathological classification of the severity of osteoarthritic lesions of cartilage, the Mankin score is frequently used. A necessary constraint on the validity of this scoring system is the consistency with which cartilage lesions are classified. The intra- and interobserver agreement of the Mankin score was determined. The intra- and interobserver agreement of the 14-point Mankin score was adequate. Between observers 95% of differences were less than approximately 7 points. By a more strict definition of the elements of the Mankin score, the intraobserver differences were reduced only for some observers. The interobserver differences were only slightly reduced: between observers 95% of differences were less than approximately 6 points. We found the Mankin score to be an adequate histopathological tool.

Animals↗
PubMed1992

The effect of piroxicam on the metabolism of isolated human chondrocytes.

The effect of piroxicam on the metabolism of healthy and osteoarthrotic (OA) chondrocytes was studied in vitro. The chondrocytes were obtained from five healthy, five moderately OA, and four severely OA hips or knees. The chondrocytes were cultured in a high-density, short-term in vitro model. In this culture, the healthy chondrocytes as well as the OA chondrocytes retain their metabolic properties. Piroxicam was used in concentrations ranging from 0 to 10 micrograms/ml, which is comparable to the concentrations reached in vivo after oral administration. In cultures of healthy chondrocytes, piroxicam inhibited proliferation and synthesis of proteoglycans. The metabolism of moderately damaged chondrocytes was not influenced by piroxicam. In severely damaged chondrocytes, the proliferation was significantly inhibited by piroxicam. In order to avoid the possible negative side effects of piroxicam on the metabolism of healthy and severely OA chondrocytes, piroxicam treatment of an OA joint with synovitis should be restricted to the period of the effusion.

Cartilage, Articular↗
PubMed1990

The potential of adult human perichondrium to form hyalin cartilage in vitro.

The usefulness of adult human perichondrium for the restoration of articular cartilage defects depends on the potential to form hyalin cartilage. In order to evaluate the capacity of adult human perichondrium to form hyalin cartilage in vitro, perichondrium of the rib of eight adult human beings was cultured in vitro. After removal of residual cartilage, perichondrial explants were cultured for 7 or 10 days. The explants were histologically examined using specific stains to prove the presence of glycosaminoglycans (GAGs) normal for hyalin cartilage. Clear differentiation of perichondrial cells towards chondrocytes was noted. The chondrocytes synthesized new matrix substances normally present in hyalin cartilage. This investigation supports the usefulness of adult human rib perichondrium for the restoration of cartilage defects. Due to the enormous potential of the rib perichondrium to form hyalin cartilage in vitro, even defects in joints with a rather thick cartilage layer might be restored using this biological material.

Adult↗