Multi-technique characterization of retrieved bone cement from revised total hip arthroplasties.

The purpose of this study was to assess the chemical composition, structure and degree of double bond conversion of retrieved bone cement from 29 total hip replacement revision arthroplasties, employing a multi-technique approach. Scanning electron microscopy revealed a porous cement surface, which replicated the characteristics of bone or femoral stem surface irregularities. Fourier transform infrared spectroscopy indicated that the retrieved bone cement samples were covered by a well-organized proteinaceous film rich in amides and alcohols, probably because of the adsorption of species from body tissues and fluids. X-ray fluorescence spectrometry showed the presence of potassium, sodium, calcium and phosphorus, implying the development of a mineralization process of the adsorbed biofilm. X-ray microtomography demonstrated a dense porous network in the bulk material comprised of macropores with a mean diameter >1 mm. FTIR analysis of the degree of double bond conversion of retrieved samples was in the order of 70%, similar to that of samples prepared in vitro in air, but 30% lower relative to their counterparts mixed in vitro and set in water. The effect of the adsorption of species onto bone cement surface on the reactivity of the material with the surrounding tissues and materials, is currently unknown. The results of this investigation reveal that the in vivo aging pattern of bone cements may involve alterations, which cannot be simulated under current in vitro protocols, emphasizing the necessity for adopting in vivo approaches including retrieval studies in assessing bone cement properties.

[Gonarthrosis: is the role of pathological statics overestimated?]. / Gonarthrose: Wird der Einfluss der pathologischen Statik überbewertet?

UNLABELLED: 57 patients (15 males and 42 females) with osteoarthrosis and/or pathological statics of the knee were examined clinically and radiographically. The question was whether pathological statics (genu varum) act significantly in the pathogenicity of the condition. FINDINGS: a) In a large number of cases it was impossible to determine whether the static deviation were the cause of the osteoarthrosis or whether the reverse were the case. b) The frequency of development of osteoarthrosis in knees with pathological statics was not greater than in those with normal statics. c) The topography of the osteoarthrosis, which one would expect to be a function of the direction of static deviation, was not more frequent in genu varum than in statically normal knees. d) In unilateral genu varum, in some cases the same degree and topography of osteoarthrosis was observed in both knees. e) In a sufficient number of cases, the amount of osteoarthrosis was minimal in relation to the degree of static deviation. f) In genu varum, a deviation was located in the proximal portion of the tibia, whereas in genu valgum, the deviation was located in the distal portion of the femur. The findings "b, c, e" were verified statistically. These findings raise doubts as to the aetiology of pathological statics in the pathogenicity of osteoarthrosis of the knee. Pathological statics alone are not sufficient and probably require other factors for the development of osteoarthrosis.

[How does bone behave when an immunologic reaction (caused by administration of antigen) is induced a long time after metal implantation]. / Wie verhält sich der Knochen, wenn erhebliche Zeit nach Metallimplantation eine immunologische Reaktion (durch Antigengabe) provoziert wird?

It has been ascertained that metal implantation in the femoral bone of rats with simultaneously induction of immunological reaction leads in all probability to intense bone damage. It is possible that the sum of all qualitative and quantitative haemodynamic and biochemical consequences from the bone injury (implantation) and the immunological reaction are responsible for this result. To investigate the above possibility, we carried out this study with a monthly delay of antigen administration after metal implantation. We found that: a) Bone alterations occur in approximately 50% of experimental animals which received antigen. b) These bone changes are shown radiologically as osteolysis of immunological reaction, respectically. c) These changes are of less intensity than those produced in simultaneous implantation and antigen administration, but of practical importance. d) None of the control animals (without antigen administration) showed any radiologically visible bone alteration. We discuss the clinical usefulness of these results.

Concentration of antibacterial agents in rat bone. A comparative study of gentamicin, ampicillin and cephaloridine.

The concentrations of Gentamicin, Ampicillin and Cephaloridine in thigh rat bone were studied. Measurements were done after a 24 h administration for 3 different times. Measurable quantities in the bone for the three antibiotics were detected. The best levels in relation with the M.I.C. of 4 microorganisms occurred in Cephaloridine (and in measurements of serum and bone (microgram/g). The concentration in the serum does not represent concentration in the bone. The most convenient parity was for Cephaloridine. The elimination of the drug in the bone was impressive after 2h. The slower fall occurred in Cephaloridine. Ampicillin had the same level in 4 and 6h. Gentamicin and Cephaloridine had failed to present measurable quantities in some of the animals of the last measurement.

[Immunological state of reaction and healing of osteotomy (author's transl)]. / Immunologische Reaktionslage und Osteotomieheilung.

The influence of immune reaction on rats - achieved through C. F. A. - on the healing of incomplete osteotomy of the femur was experimentally examined. It was found that the production of immune reaction, manifested by the appearance of polyarthritis, leads in a great percentage (60% of the animals) in extensive bone destruction in the vicinity of the osteotomy. The results were examined clinically, radiologically and histologically. The type of reacton in the area of bone destruction was of immunological origin (histological examination).

[Bone reaction to metal and bone cement implants at immunologic reaction level in rats (author's transl)]. / Knochenreaktion auf Metall- und Knochenzement-Implantation bei immunologischer Reaktionslage, bei Ratten.

After the fact that femoral osteotomy in rats results in destruction of the entire bone (in the majority of experimental animals) due to an immunological reaction by means of Complete Freund's Adjuvant, we have investigated whether or not the implantation of bone cement or Kirschner wires affects additionally the condition of the bone. We have found that bone cement or metallic material within the bone cavity aggravates osteolysis if there is an immunologic reaction present. The conditions of the immunologic mechanism and the applied orthopedic procedures are discussed and an attempt has been made to explain the phenomenon.

[Aseptic necrosis of the femur head in congenital hip dysplasia. Radiological signs for a prediction or an early diagnosis (author's transl)]. / Luxationsperthes--Gibt es röntgenologische Möglichkeiten für die Voraussage und der Frühdiagnose?

Radiographs an patient histories of 36 children were examined in order to determine radiological signs that would allow a prediction or an early diagnosis of the aseptic necrosis of the femur head nucleus (Luxations-Perthes) during the treatment of hip dysplasia. Necrosis of the nucleus appeared in 17 joints (of 15 children). We had the following findings: a) Mikroepiphyses have a high risk (59%). b) In all cases of necrosis the angles of the femur neck near epiphysis were rounded, while this sign was never found in dysplastic joints without necrosis.

[Correction osteotomies of the knees. Factors altering the static angles on the radiographies through fault projection (author's transl)]. / Korrekturosteotomien am Knie. Faktoren, welche die Messwinkel auf a.p. Röntgenaufnahmen, durch Verprojizierung, verändern

Comparing radiographies we have examined the degree in which the static angles of the knee are affected, because of a fault projection under the influence of some factors. We have found that an inwards or an outwards turn, even of a small degree (IQ), a bending or preexistent (pathological) anomalies, each alone or in combination, affected the right projection of the angles in a face radiography. Physiological knees possibly are presented like "varum" or "valgum" projectional. It is clear that the right position during the taking of the radiography is of a great significance in order to decide about the indication of osteotomy and to determine the degree of correction. We suggest as a criterion of the right radiographies the factor "patellacondylus".

[Intertrochanteric displacement osteotomy. Is displacement useful (author's transl)]. / Intertrochantere Verschiebungsosteotomie. 1st die Verschiebung zweckmässig

When displacement intertrochanteric osteotomy is performed for osteoarthritis of the hip, the factor "displacement" does not affect at all the pressure exerted on the articular faces of the hip (basic aim in prevention and treatment of osteoarthritis). The good effect of osteotomy should be attributed to the factor "biological stimulation" or "blood circulation". Therefore displacement should be avoided because it causes complication (pseudarthrosis) and difficulties when eventually total arthroplasty has to be performed which is (sooner or later) necessary in most cases.