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Indomethacin treatment in osteoarthritis of the hip joint. Does the treatment interfere with the natural course of the disease

The course of osteoarthritis in 294 hips of 186 patients was evaluated by examining their radiographs. The development of the disease in patients treated with indomethacin was compared with that in a control material. In the indomethacin group the disease progressed more frequently and in one parameter the progress was more severe. The results support previous reports indicating that indomethacin might have a deleterious effect on osteoarthritic hip joints. Some possible explanations for this adverse effect of indomethacin treatment are discussed.

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. No influence of castration on the mechanical strength of the femora could be detected in either sex. At 2 weeks after castration, the circulating levels of immunoreactive calcitonin (iCT) were decreased in female rats compared to controls. In contrast, iCT was increased both in castrated male and female rats 10 weeks later. We conclude that castration of 6-month-old female rats causes osteoporosis, and therefore represents a promising experimental model for studying postmenopausal bone loss.

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. Fractures with negative predictive signs may be selected for primary arthroplasty.

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.

Bone formation enhanced by induction: Bone growth in titanium implants in rats

Bone-inducing materials have been investigated for the purpose of augmenting bone formation in implants made of porous fiber titanium. The bone-inducing materials used were: (1) Bone from the iliac crest of inbred rats (isografts), (2) Antigen-extracted, autolyzed, demineralized bone from outbred rats (AAA bone a.m. Urist), and (3) AAA bone combined with bone marrow from inbred rats. Tubes of fiber titanium were packed with bone-inducing materials and implanted in the back musculature of inbred rats. Bone formation was assessed by labelling with 3H-proline (collagen synthesis) and 47Ca (mineral deposit) and by content of calcium of the harvested implants. Isografts and AAA bone with marrow yielded a substantial amount of new bone. Without the marrow, AAA bone yielded very small amounts of new bone.

Larsen's syndrome.

A girl with the characteristic abnormalities of Larsens syndrome is presented. A soft flabby consistence of the cartilaginous skeleton of the larynx and trachea was thought to be the cause of attacks of respiratory failure which suddenly caused her death at the age of 9 months. Microscopy revealed a considerably reduced number of elastic fibres in the larynx, trachea and bronchi. Closed reduction of the knee dislocation by skin traction seemed to be successful.

Invasion of bone into porous fiber metal implants in cats.

Bone ingrowth in porous Ti-6Al-4V implants in feline femurs was assessed for the amount and composition 4, 12 and 26 weeks after implantation. During the first 12 weeks there was a rapid ingrowth that levelled out during the ensuing weeks. Bone had penetrated the implants to an average depth of 0.5 mm over their entire surface at 26 weeks. The ingrown bone was deficiently mineralized at 4 and 12 weeks, but reached full mineralization at 26 weeks. A low calcium to phosphorus ratio persisted at all observation times. The ingrown tissue was compared to bone filling drill holes that had been made in the trochanters contralaterally to the implants. By means of radioactive strontium, the mineral deposits in the holes and implants could be compared. The overall results indicate that bone ingrowth in a porous implant and bone healing are similar processes both qualitatively and quantitatively.

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 0.05 r of torsion the load-deformation test showed that three von Bahr screws provided the strongest fixation, and this was confirmed by the the ultimate torsional moment test. Regardless of positioning, even two von Bahr screws were stronger than the sliding compression screw with or without an additional lag screw. The results indicate that the best torsional stability in femoral neck fractures can be obtained with three 5.5-mm screws.

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. Cancellous bone was defined with threshold limits ranging from 50-500 Hounsfield units (HU), and attenuation values exceeding 500 HU were assessed as cortical bone. The recorded QCT mass-related measures of cortical and cancellous bone separately and as total bone masses gave significant right/left correlations. Correlations were found between the ultimate torsional strength of the femoral neck and QCT recordings of bone mass at all the femoral levels. The best correlations were demonstrated between the rotational strength of the femoral neck and the total bone-mass-related measures in the femoral shaft and condylar area. Bone mass of the femur measured by computed tomography may become useful as an index of the mechanical strength of the femoral neck.

Comparison of ceramic and titanium implants in cats

The mechanical strengths of the bone-implant interfaces of titanium coated with glass ceramic and pure titanium implants were compared. The glass ceramic had a chemical composition similar to 45S5F Bioglass. Cylindrical implants were placed in feline femurs. Six weeks later the strength of the fixation was tested using pull-out tests. Energy dispersive X-ray microanalysis was applied to pursue any possible relationship between mechanical strength and changes in elemental composition at the bone-implant interface. The ultimate shearing force for the pure titanium implants was higher than for the implants coated with glass ceramic. Also, the glass ceramic coating was partly degraded by the tissues. Evidently, the mechanical properties of the glass ceramic to bone interface were governed by some sort of chemical reaction that implied transfer of elements from the implant to bone. It appears that this reaction eventually will destroy the coating which makes this kind of material unsuitable for prosthesis fixation.