Nuclear imaging in loosening of hip-joint endoprostheses.

In 28 patients with surgically proved loosening of hip-joint endoprostheses and 42 patients without loosening between 2 and 12 years after implantation and without clinical or radiological signs of loosening we performed clinical evaluation, and radiographs, a three-phase bone scan, and a 111indium-labeled leukocyte scan (ILLS). The sensitivity of radiographs in the group with loosening of hip-joint endoprostheses in the femoral as well as in the acetabular component was only about 50%, while the specificity was almost 100%. With a combination of radiographs and ILLS we reached a sensitivity in the acetabular component of 100% and in the femoral component of 88%, but specificities of only 57% in the acetabular component and 40% in the femoral component were found. We found that the ILLS is a very helpful method of examination to detect loosening of hip-joint arthroplasties in doubtful cases.

Trace element burdening of human tissues due to the corrosion of hip-joint prostheses made of cobalt-chromium alloys.

Using instrumental neutron activation analysis, the concentrations of 18 elements were studied in human articular capsule and fascia lata before and after application of total endoprostheses of the hip joint made of cobalt-chromium alloys. Tissues from the vicinity of the implant showed extreme burdening by corrosion products (Co, Cr, Ni), as well as by Zr, Hf, and Ba from the bone cements. Tissues more distant from the implants exhibited lower, but still significant burdening. Moreover, some essential trace elements not contained in the implant materials were changed in the tissues after implantation. In order to clarify the dissolution of alloy constituents in biological media, the passivation of cobalt-chromium alloy was investigated by tracer techniques using Ringer's solution as a simple model of the body fluids. The passivation process lasted for more than 1 month and was accompanied by a selective dissolution of the alloys constituents in the order Ni greater than Co approximately Fe greater than Mo greater than Cr. A comparison of the tissue analyses with the corrosion experiments demonstrates that the distribution patterns of the corrosion products in the tissues are influenced by both the corrosion process and the biochemical properties of the corrosion products.

[Tissue burden with exogenous trace elements caused by roentgen contrast media in bone cements]. / Gewebebelastung mit körperfremden Spurenelementen durch Röntgenkontrastmittel der Knochenzemente.

In 44 patients undergoing a change of total hip prosthesis, made of Co-Cr alloy and at one point with a Refobacin-Palacos chain we analyzed samples of the hip joint capsule and fascia lata. Using Instrumental Neutron Activation Analysis (INAA) up to 18 elements were analyzed. The findings demonstrate that the tissues in the surroundings as well as in direct contact with the total hip prosthesis are burdened by corrosion products of the alloy and by decomposition of the bone cement. The decomposition of bone cement can be shown in the extraordinary high concentration of Barium, Zirconium and Hafnium which are added to Bone Cements as X-ray contrast. Microscopic findings at the same time complete and confirm the trace element analyses.

[Studies on the presence of metal traces in tissue surrounding A.O. angle plates, based on neutron activation analysis (author's transl)]. / Untersuchungen zum Verhalten von Metallspuren im umgebenden Gewebe von AO-Winkelplatten mit Hilfe der Neutronenaktivierungsanalyse.

Using instrumental neutron activation analysis, 11 samples of tissue in contact with A.O. angle plates and 8 samples of fascial tissue were examined for their content of trace elements, half a year to 5 1/2 years after hip joint intertrochanteric osteotomies. Significant increases in the concentrations of the elements Cr, Fe, Co, Ni and Mo, all of which are contained in the A. O. steel plates (V4A steel), were found both in the contact tissue and in the tissue of the fascia lata femoris about 4--8 cm away from the angle plates, whereas the levels of concentration of elements not specific for the alloy in question, namely, Zn, Se, Rb and Cs, were normal or just subnormal. It was possible to prove by means of element correlations that the elements Cr, Co, Ni and Mo are present in constant ratios in those tissue samples which are loaded with traces of metals foreign to the body. However, only the Mo:Cr ratio corresponds to that of the angle plates. The authors considered Ni to be a useful indicator for the degree of metal loading of a tissue, since Ni will normally occur in human tissue in very low concentrations (less than or equal to 10(-6) g/g dry substance) and was identified by the authors--contrary to previous studies--even in the fascial tissue located up to 8 cm away from the contact tissue. Non-linear correlations were found between iron and the other components of the steel, reflecting the complicated regulatory mechanisms governing the presence of iron in the organism. The results of the analysis are discussed in respect of possible long-term action of the implantate components liberated by corrosion, which, in case of long-term implantates might place an overall burden of foreign ions on the body.

[The painflu stiff shoulder following radical neck dissection (author's transl)]. / Zur schmerzhaften Schultersteife nach Radical Neck Dissection.

72 patients following radical neck dissection were studied. The accessory nerve was sacrificed in 60 patients and preserved in the remaining patients (for a control group). The most important clinical findings in all patients are reported. Most patients with loss of the accessory nerve complained more of postoperative pain and limitation of shoulder movement than of other clinical difficulties or cosmetic defects.