Pressure during compaction of morsellised bone gives an increase in stiffness: an in vitro study.

Morsellised bone impaction is used in joint prosthesis revision surgery to repair structural damage to the periarticular bone stock. The initial stiffness of the impacted bone is crucial for the survival of the revised hip joint. Impaction of morsellised bone in a femoral canal can cause fractures that may induce implant loosening in both femur and acetabulum.

Factors affecting stiffness properties in impacted morsellized bone used in revision hip surgery: an experimental in vitro study.

When revising loosened joint prosthesis, impacted morsellized bone is frequently used as organic scaffolding. We studied the relative influence that different bone particle size, impaction energy, and liquid content had on impacted bone stiffness. Bovine bone was morsellized in a bone mill by three grinding drums to produce bone with different chip size distribution.

Influence of water and fat content on compressive stiffness properties of impacted morsellized bone: an experimental ex vivo study on bone pellets.

Background: The initial stability of an exchanged hip arthroplasty is crucial for the survival of the revised joint. Several factors can affect the outcome. The amount of liquid in morsellized bone has a major influence on the constrained stiffness properties of impacted bone applied in revision joint surgery.

Viscoelastic modelling of impacted morsellised bone accurately describes unloading behaviour: an experimental study of stiffness moduli and recoil properties.

Morsellised bone impaction grafting is commonly used for revision arthroplasty surgery. Several reports have described the mechanical behaviour of this bone material during impaction and loading. In this study we observed the unloading progress.

Impacted bone stiffness measured during construction of morsellised bone samples.

Impacted morsellised bone is widely used for filling bone deficiencies during revision of total hip arthroplasties. However, the physical properties and mechanical behaviour of this bone material are still not well understood. In this study we recorded the increase of stiffness in pellets of morsellised bone during their construction.

Lower limb amputations: registration of all lower limb amputations performed at the University Hospital of Trondheim, Norway, 1994-1997.

The authors consecutively recorded all lower limb amputations performed at the University Hospital of Trondheim from January 1st, 1994 to January 1st, 1997. A total of 215 primary lower limb amputations were carried out in the study period: 40 partial foot amputations, 2 ankle disarticulations, 51 trans-tibial amputations, 68 knee disarticulations, 50 transfemoral amputations and 4 hip disarticulations. Seventy-four (74) (34%) of the amputees had diabetes mellitus, 113 (53%) had peripheral vascular disease and 28 (13%) of the amputees had various diagnoses.

[Treatment of clubfoot].

48 patients (70 club-feet) were reviewed clinically between the age of 4 and 14 years. The primary treatment had been serial plaster casts in the case of 43 feet and additional neonatal tenotomies in 27 feet. Operative treatment after the neonatal period was performed on 53 feet (75%) at a median age of ten months (2-60 months).

Surgically induced uremia in rats. I: Effect on bone strength and metabolism.

During the course of chronic renal failure (CRF) in man, renal osteodystrophy (osteitis fibrosa and/or osteomalacia) gradually develops. The present study aimed to establish a similar type of CRF leading to renal osteodystrophy in rats. During progressive CRF development over 225 days after 5/6 nephrectomy, the following serum variables were measured: creatinine, immunoreactive parathyroid hormone (iPTH), 1,25-dihydroxyvitamin D3 (1,25(OH)2D3), a25-hydroxyvitamin D3, (25(OH)D3), alkaline phosphatase, albumin, phosphate, urea nitrogen, total calcium, and other blood electrolytes.

Ultrasound examination for measurement of femoral anteversion in children.

Femoral anteversion (AV) angles were determined by ultrasound and biplanar radiography in 63 children aged 3-11 years. With the patient supine, knees flexed 90 degrees, and legs kept vertical, only one ultrasound scan of the proximal femur was needed. The anterior tangent of the femoral head and the greater trochanter was used as the reference line.

Prediction of disturbed healing in femoral neck fracture. Radiographic analysis of 149 cases.

To determine factors predictive of early healing disturbances after fixation of femoral neck fracture, the radiographic and clinical data of 149 patients were subjected to a logistic regression analysis comparing them with the results 3 months postoperatively. As in previous studies, fracture reduction distinguished between fractures with or without healing disturbances. The following signs in the preoperative radiographs were predictive of unfavorable outcome: small head fragment, comminution of the calcar femorale, and varus angulation of the head.

Slotted versus non-slotted locked intramedullary nailing for femoral shaft fractures.

Experimentally, two slotted nails, the Grosse-Kempf nail and the AO/ASIF universal femoral nail, were compared to the non-slotted Grosse-Kempf nail and control bone using a cadaver femoral osteotomy. The stiffnesses and strengths of the osteotomies fixed with slotted nails in 10-30 degrees torsion were 6-8% and the values of non-slotted nails 40% of control bone. The maximal moments were 14-18% and 48%, respectively.

Radiographic prediction of early failure in femoral neck fracture.

We studied the primary radiographs of 56 patients treated with osteosynthesis for a displaced femoral neck fracture. The radiographic findings were subjected to a multiple regression analysis together with the results 3 months postoperatively. A primary fracture displacement of more than 20 mm on the AP film and a defect of the calcar due to fracture comminution were associated with a failed osteosynthesis.

Stability of femoral neck osteosynthesis. Comparison of fixation methods in cadavers.

Fixation of vertical femoral neck osteotomies in 50 cadavers was performed with either von Bahr screws or a sliding hip compression screw. One specimen from each pair of femora was used for the osteotomy, the other serving as an intact control. At 0.

Rotational strength of the femoral neck. Computed tomography in cadavers.

The mean bone density of the femur at different levels was determined by means of quantitative computed tomography (QCT) in 50 pairs of normal cadaveric femora and related to the rotational strength of the femoral neck. All the femora fractured vertically and spirally in the neck. The bone-mass-related measures at different levels were calculated from QCT densities and volumes.

Ultrasonography and parameters of inflammation in acute appendicitis. A comparison with clinical findings.

A prospective study of 110 unselected patients with suspected acute appendicitis comprised ultrasonography and parameters of inflammation--c-reactive protein, white blood cell count, erythrocyte sedimentation rate and Yersinia antibody titer. The results were compared with the initial clinical diagnosis. Acute appendicitis was confirmed in 28 cases (prevalence 25.

Comparison of bone reactions to coated tricalcium phosphate and pure titanium dental implants in the canine iliac crest.

Titanium and TCP-coated implants were compared after insertion in the canine iliac crest. Observation time was 14 wk. Evaluation included pull-out tests, energy dispersive X-ray analysis, and histologic examination of in situ, undemineralized implants.

Limb lengthening by epiphyseal distraction. An experimental study in the caprine femur.

Epiphyseal distraction of the left distal femur was accomplished in 10 goats (aged 3-4.5 months). A modified Hoffmann external fixation device was used as a unilateral distraction frame.

Effects of acetylsalicylic acid on intramuscular bone matrix implants and composite grafts in rats.

Antigen-extracted, autolyzed, demineralized bone matrix and bone matrix combined with isogeneic bone marrow (i.e., a composite graft) were placed in the musculature of young male rats.

Bone changes after castration in rats. A model for osteoporosis.

Bone changes 6-12 weeks after castration have been studied in 25 female and 27 male middle-aged rats. Castrated female rats gained more weight than their controls, but had decreased bone density and calcium and hydroxyproline content per cm3 bone volume of tibia. Castrated male rats did not differ from controls regarding body weight and the bone parameters.

Bone fixation of ceramic-coated and fiber titanium implants. A study in weight-bearing rats.

We compared the fixation of glass ceramic-coated titanium and fiber titanium implants using a simple weight-bearing model in rats. The chemical composition of the glass ceramic was similar to 45S5F Bioglass. One hundred and eight male Wistar rats were operated on.

Osteogenesis promoted by bone matrix combined with marrow. Titanium implants studied in rats.

We evaluated the bone-forming potential of isogeneic bone marrow combined with antigen-extracted, autolyzed allogeneic bone matrix (AAA bone a.m. Urist).

Effects of acetylsalicylic acid and naproxen on the mechanical and biochemical properties of intact skin in rats.

Acetylsalicylic acid, ASA (150 mg/kg/12 h), and naproxen (20 mg/kg/12 h) were administered to young male rats for 9 and 18 days. The doses were set to provide serum concentrations comparable with anti-inflammatory steady state levels in humans. Mechanical tests were performed on skin from the back of the rats.

Effects of acetylsalicylic acid and naproxen on bone resorption and formation in rats.

The influence of acetylsalicylic acid (ASA) (150 mg/kg/12 h) and naproxen (20 mg/kg/12 h) on bone metabolism in young male rats has been studied. The doses were chosen to provide serum concentrations comparable with ordinary anti-inflammatory steady-state levels in humans. After the rats had been prelabeled with collagen- and mineral-tracing radioisotopes the rats received the drugs by gavage twice a day for 9 and 18 days.

Bone ingrowth into weight-bearing porous fiber titanium implants. Mechanical and biochemical correlations.

Bone ingrowth into weight-bearing porous fiber Ti-6Al-4V implants in rat tibias was assessed for the amount, composition, and mineralization rate 3, 12, and 26 weeks after implantation. The data were compared with the ipsi- and contralateral metaphyseal controls and related to the ultimate bending stresses of the distal bone/implant interfaces. From the 3rd to the 12th week there was rapid bone ingrowth and also marked decline in mineralization rate of the ingrowing bone.

Effects of acetylsalicylic acid and naproxen on the mechanical properties of intact femora in rats.

The influence of acetylsalicylic acid (ASA) and naproxen on growing bones was studied. Young male rats were used. The drugs were administered via gastric gavage twice a day for 9 or 18 days.