Some complications of common treatment schemes of thoracolumbar spine fractures can be predicted with magnetic resonance imaging: prospective study of 53 patients with 71 fractures.

Study Design: Prospective cohort study.

Objectives: To study the predictive value of magnetic resonance imaging (MRI) findings of thoracolumbar spine fractures concerning the radiologic and clinical outcome.

Summary Of Background Data: Disagreement about the proper treatment of thoracolumbar spine fractures is caused by insufficiency of conventional imaging techniques.

Balloon vertebroplasty with calcium phosphate cement augmentation for direct restoration of traumatic thoracolumbar vertebral fractures.

Study Design: A human cadaveric model was used to evaluate balloon vertebroplasty in traumatic vertebral fractures.

Objectives: To assess the feasibility and safety of balloon vertebroplasty followed by calcium phosphate cement augmentation to prevent recurrent kyphosis.

Summary Of Background Data: Failure after short-segment pedicle-screw fixation for the treatment of vertebral fractures is probably caused by a redistribution of disc material through the fractured endplate into the vertebral body, causing a decrease in anterior column support.

Tobramycin-containing bone cement and systemic cefazolin in a one-stage revision. Treatment of infection in a rabbit model.

The efficacy of tobramycin-containing bone cement with that of systemic cefazolin for treatment of infection in a one-stage revision model is compared. In addition, the value of detecting bacterial DNA after antibiotic treatment was investigated. An implant was inserted into the right tibia of rabbits after inoculation with Staphylococcus aureus.

Traumatic lumbosacral dislocation: case report.

Study Design: A case report of a bilateral lumbosacral dislocation without a fracture is presented.

Objective: To report the diagnosis and treatment of a traumatic lumbosacral dislocation.

Summary Of Background Data: Lumbosacral dislocations without fractures are rare injuries, with only four cases reported in literature.

Prophylaxis of implant-related staphylococcal infections using tobramycin-containing bone cement.

In a rabbit model, premixed tobramycin-containing bone cement was studied for its efficacy to prevent infections with two frequently encountered staphylococcal species in arthroplasty surgery. After intramedullary inoculation with staphylococci, either standard or premixed tobramycin-containing Simplex-P bone cement was injected in the right femur of 120 rabbits. Development of infection was examined by culture of femoral bone after 7 or 28 days.

Prevention of infection with tobramycin-containing bone cement or systemic cefazolin in an animal model.

We investigated in an animal model the efficacy of tobramycin-containing bone cement and systemic cefazolin for infection prophylaxis. In 18 female rabbits, the femoral cavity was inoculated with Staphylococcus aureus before injection of bone cement. The first group of six rabbits received tobramycin-containing Simplex-P bone cement.

Effects of hydrosyapatite coating on Ti-6A1-4V implant-site infection in a rabbit tibial model.

To investigate the effect of implant type after direct contamination, a hydroxyapatite-coated or noncoated Ti-6A1-4V implant was inserted into both tibiae of 32 New Zealand White rabbits. Prior to implantation, the left tibia was contaminated with increasing concentrations of Staphylococcus aureus (10(2)-10(5) colony-forming units), ranging from very low (10(2)) to relatively high (10(5)). Four weeks after implantation, half of the tibial bone adjacent to the implant was harvested for bacteriological examination.

MRI findings of thoracolumbar spine fractures: a categorisation based on MRI examinations of 100 fractures.

Objective: To define the state of different structures of the fractured thoracolumbar spine which may play a role in the immediate and long-term mechanical stability on MR images and to investigate the relationship of these findings with the AO classification of spinal injuries.

Design: The state of the anterior longitudinal ligament, posterior longitudinal ligament, posterior ligamentous complex, cranial and caudal endplates, cranial and caudal discs and the vertebral body were defined using clinical, experimental and radiological data. The state of these structures was reported for each fracture on the MRI examinations and the different MRI features appropriate for different fracture classes were defined.

Critical size defect in the goat's os ilium. A model to evaluate bone grafts and substitutes.

Bone defects and their treatment are a well known problem in orthopaedic surgery. A critical size defect is a suitable model to study bone replacement materials. This study describes a critical size defect in the goal and the evaluation of three bone fillers (particulate autograft, particulate allograft, and a polyethylene oxide/polybutylene terephthalate copolymer) in this defect.

Correlation of MR images of disc injuries with anatomic sections in experimental thoracolumbar spine fractures.

This cadaver study evaluated the value of MR images for detection of acute intervertebral disc damage associated with fractures of the thoracolumbar spine. Damage to the intervertebral disc may be a major contributor to chronic instability in non-operative treatment or failure of fixation and recurrence of deformity in posterior fixation methods. MR imaging can help us to understand the injury patterns and their prognostic significance.

Changes in the disc space after fractures of the thoracolumbar spine.

We have studied the intervertebral discs adjacent to fractured vertebral bodies using MRI in 63 patients at a minimum of 18 months after injury. There were 75 thoracolumbar fractures of which 26 were treated conservatively and 37 by posterior reduction and fusion with an AO internal fixator. We identified six different types of disc using criteria based on the morphology and the intensity of the MRI signal.

[An estimate of the intramural costs of the placement of a total hip prosthesis].

Objective: Determining the intramural costs of the (re) placement of a total hip prostheses.

Design: Retrospective, descriptive.

Setting: Utrecht University Hospital (AZU) and the De Weezenlanden Hospital in Zwolle (ZWZ), the Netherlands.

[Total hip replacement arthroplasty in the Netherlands].

The total hip arthroplasty (THA) is an effective treatment of osteoarthritis of the hip joint. Each year, more than 16,000 THAs are performed in the Netherlands. The incidence of THA had doubled between 1980 and 1994.

Integration of press-fit implants in cortical bone: a study on interface kinetics.

The early healing phase of hard tissue implants is important to their long-term success. Problems during this phase can result in a so-called primary biological failure. In 24 New Zealand white rabbits, the healing in cortical bone of noncoated TiAlV and cpTi cylinders and of TiAlV cylinders plasma-spray-coated with hydroxyapatite (HA) of fluorapatite (FA) was investigated histologically and histomorphometrically after 3, 7, 14, and 28 days.

[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.

The prevention of peridural adhesions. A comparative long-term histomorphometric study using a biodegradable barrier and a fat graft.

We studied peridural fibrosis in 16 dogs after laminectomies at the L2, L4 and L6 levels. They received either a free fat graft, a biodegradable mechanical barrier (polyethylene oxide (PEO)/polybutylene terephthalate (PBT) copolymer), or no treatment. The animals were killed after 4, 12, 26 and 52 weeks.

Healing of gaps around calcium phosphate-coated implants in trabecular bone of the goat.

Hydroxylapatite coatings are under clinical investigation in orthopaedics and dentistry. Bone formation on apatite coatings in the presence of gaps is important for clinical applications. The importance of the stability of the coating is not known at present.

Periarticular aneurysm formation in haemophilia.

Background: Spontaneous bleeding into the joints is common in haemophilia. Recurrent intra-articular bleeding leads to joint destruction. In the past 4 years we have carried out sixteen total knee replacements for haemophilic arthropathy.

Semi-quantitative and qualitative histologic analysis method for the evaluation of implant biocompatibility.

An adequate histologic evaluation is a prerequisite for a good understanding of the behavior of tissue to implant materials. However, despite improvements in histologic sectioning techniques, few studies have used histomorphometric methods for the quantification of the tissue response. This paper discusses new simple histologic grading scales, which can be used for the fast standardized light microscopic analysis of the biocompatibility of hard and soft tissue implants.

Retrieval studies on calcium phosphate-coated implants.

The search for the improvement of implant fixation in bone resulted several years ago in the introduction of calcium phosphate coatings on orthopaedic (and dental) implants. Since then many animal experiments, especially on hydroxylapatite coatings, have been performed. By now the first promising results from clinical studies are also available.

In vitro study on the integrity of a hydroxylapatite coating when challenged with staphylococci.

An in vitro study was performed to evaluate the effect of Staphylococcus aureus and Staphylococcus epidermidis on the integrity of a hydroxylapatite coating. The coating plasma-sprayed on poly(L-lactide), showed dissolution during a 24 h incubation period. This was indicated by an increase in pH and calcium release in the buffer solution.

Adherence to a metal, polymer and composite by Staphylococcus aureus and Staphylococcus epidermidis.

Bacterial adherence on to several materials with a potential application in reconstructive surgery was studied. Polymer (poly(L-lactide)), composite (hydroxyapatite/poly(L-lactide)) and metal (316L stainless steel) were evaluated both as smooth and sandblasted specimens. All materials were incubated in phosphate-buffered saline, challenged with Staphylococcus aureus or S.

A histological and histomorphometrical investigation of fluorapatite, magnesiumwhitlockite, and hydroxylapatite plasma-sprayed coatings in goats.

Plasma-sprayed ceramic coatings of fluorapatite (FA), magnesiumwhitlockite (MW), and hydroxylapatite (HA), and noncoated Ti-6Al-4V alloy (Ti) implants were evaluated histologically and histomorphometrically in a goat animal study. Cylindrical Ti-6Al-4V plugs were plasma-spray-coated with FA, MW, and HA. Noncoated, grit-blasted Ti plugs served as controls.

A finite element analysis of the push-out test: influence of test conditions.

The commonly used method for quantitative evaluation of the strength of a bone-implant interface is the push-out test. In order to give an impulse to standardization and to gain more insight in the biomechanics of the push-out test, a finite element analysis of this test was performed. This study focused on the influence of test conditions on the push-out results.