Periprosthetic tissue metal content but not serum metal content predicts the type of tissue response in failed small-diameter metal-on-metal total hip arthroplasties.

BACKGROUND: Tissue responses to periprosthetic metal wear debris are complex and poorly understood. There are two predominant tissue responses: a nonspecific macrophage-mediated granulomatous response and lymphocyte-dominated response, which has immunological memory and is mediated by T cells. Delayed hypersensitivity-type responses may accelerate aseptic loosening of arthroplasty implants. We hypothesized that the metal content of periprosthetic tissue but not of serum would be predictive of the type of tissue response to metal wear debris. METHODS: We examined twenty-eight total hip arthroplasty implant retrievals from twenty-seven patients who had undergone revision arthroplasty at one institution. Indications for revision were pain and/or osteolysis; one patient had recurrent dislocations. Tissue samples were analyzed microscopically and the metal (Co, Cr, and Ni) content was determined. Explanted prosthetic components were examined for linear wear. Intraoperatively, periprosthetic metallosis was observed in twelve cases and formation of a bursa (pseudotumor) was observed in thirteen. The acetabular cup was loose in eleven cases, the femoral stem was loose in five, and both components were loose in five. RESULTS: The metal (Co, Cr, and Ni) content of the periprosthetic tissue ranged from 1.4 to 4604.0 µg/g. Histologically, macrophages containing metal particles as well as diffuse and perivascular lymphocytic infiltration were observed. Fibrin exudation was also visible. Tissues that displayed a predominantly lymphocytic response had a mean metal content of 222.2 ± 52.9 µg/g, whereas those that displayed a macrophage-dominated response had a metal content of 3.0 ± 0.9 µg/g; this difference was significant (p = 0.001). The mean serum metal content did not differ significantly between the two subgroups (60.7 ± 13.4 compared with 43.7 ± 3.8 µg/L, p = 0.105). CONCLUSIONS: An association between periprosthetic tissue metal content and hypersensitivity appears likely but needs to be validated with larger-scale retrieval studies. CLINICAL RELEVANCE: This study contributes to the understanding of tissue responses to metal wear debris after joint replacement and the factors that are predictive of a type-IV lymphocyte-dominated hypersensitivity reaction.

Minimally invasive total hip replacement via the anterolateral approach in the supine position.

Total hip arthroplasty through minimally invasive procedures potentially reduces operative trauma, which is expected to result in improved recovery and rehabilitation. We presently perform total hip arthroplasty using minimally invasive techniques via an anterolateral modification of the Watson-Jones approach. This approach is performed in the supine position and requires sterile draping of both legs. It also involves a modified operative technique which preserves the pelvitrochanteric muscles and extends the release of the hip capsule. In order to employ a proven implant system (BICON-PLUS threaded cup, SL-PLUS stem), it was necessary to modify the stem rasps and use manipulation rasps as trial stems. In this report, we compare 50 conventional total hip replacements with 50 procedures performed using the minimally invasive procedure in terms of blood loss and the duration of the operation. The length of the skin incision varied between 7 and 12 cm with the minimally invasive technique, compared to 15 to 22 cm with the conventional procedure. Both groups were virtually identical with respect to average blood loss (haemoglobin on 10th post-operative day: minimally invasive group, 108.0 g/L; conventional group, 112.0 g/L) and the duration of the procedure (minimally invasive group, 60 minutes; conventional group, 58 minutes). The position of the implanted components correlated with the pre-operative planning with regard to medial head offset, centre of rotation of the hip, and leg length, and was as satisfactory as that observed with the conventional procedure. The complication rate was low (2.9%). Shaft fissures occurred in the first months of use of the minimally invasive procedure before adaptation of the shaft rasps. Dislocations were attributable to improper patient behaviour. Minimally invasive surgery via the anterolateral approach in the supine position was equivalent to the conventional procedure, had a low rate of complications, and did not adversely impact the technical success of the procedure.

Acatalasia discovered by accident during a disk operation.

During a disk operation, the wound was flushed with hydrogen peroxide, resulting in a blackish brown discoloration of the musculature without the formation of foam. Clinical observation caused the experienced biochemist to make the diagnosis of suspected acatalasia, a rare congenital metabolic defect which is inherited autosomally recessively. Investigation of the catalase activity in the hemolysate of the patient and his brother confirmed this suspicion and resulted in the first diagnosis of this condition in Austria.

[Intraoperative measurements of the oscillatory impedance in scoliotic patients (author's transl)]. / Oszillatorische Impedanz als intraoperativer Lungenfunktionsparameter bei Skoliosepatienten.

In 10 Skoliose-patients undergoing Harringtons-Operation, measurements of the oszillatory impedance and arterial blood gases were made intraoperatively. The resistance was elevated from the beginning without any change during the operation. The phase was in the inductive range with a further deviation during increasing extension. The possible reasons are the maximal rigidity of thorax and/or parenchyma or change in tracheobronchial "arborisation". Increase in dead space or changes in ventilation-perfusion ratio are suggested by the blood gas measurements. Further investigations will be necessary to determine, if the impedance of the lung is of value in determining the amount of intraoperative extension or postoperative lung function.

[Experimental investigations on the growth of the vertebral column after dorsal spondylodesis (author's transl)]. / Experimentelle Untersuchungen über das Wachstum der Wirbelsäule nach dorsaler Spondylodese.

To investigate the question which growth processes take place in dorsally stiffened vertebral regions, 4 vertebral segments each were dorsally fused in twenty-one pigs, using Harrington's distraction system in 20 cases. X-ray examination and histological measurements conducted with the aid of fluorochromosequential markings showed a more or less pronounced growth of the vertebral bodies and of the fusion mass in all animals. As a rule, the sequence of vertebral bodies overgrows the fusion mass in longitudinal direction, which always results in lordosis of the stiffened region. The longitudinal growth of the vertebral bodies, and even more so of the fusion mass, decreases with increasing postoperative observation time. The fusion mass shows actual internal growth which proceeds partly in diffuse manner in all directions, in the region of the clefts, i.e. as spondyloschisis, in some cases also in the same direction as with enchondral ossification associated with columnar chondrification. The growth of the fused mass does not depend on the formation of a pseudoarthrosis, although it is probably quantitatively promoted by pseudarthroses. The stimulus to longitudinal growth of the fused mass originates from the growing vertebral bodies, with probably varying influence of tensile and compressive forces.

[Long bone healing after transverse osteotomy under constant interfragmentary compression. Animal experiments (author's transl)]. / Knochenheilung nach querer Schaftosteotomie unter konstantem interfragmentärem Druck.

The reaction of cortical contact areas, after osteotomy of a tubular bone, to a constant interfragmentary pressure has not been studied in exact terms so far because of lack of an adequate testing system. The present experimental study therefore examines the influence of various, but during the experiment constant, static pressures on the healing process of the cortical bone. Departing from the basic interrelation between fixation and interfragmentary compression (in the following briefly called: pressure) and from the resulting more or less limited mobility of the bone parts, following osteotomy, it appeared necessary to concentrate observation on either of the two parameters "fixation" or "pressure" alone. For this animal experiment a suitable external compression apparatus was developed so as to secure the application of a constant pressure. The present study contains construction drawings and data on the constructional assembly and integration of these newly developed compression apparatuses and pressure measuring devices. The compression apparatuses permit by variable spring configurations to produce pressures up to a maximum force of 1000 newton. To control the pressure exerted over a period of many weeks, a special measuring system had to be used to provide for a correction of the losses of pressure as occurring, for different reasons, during the progress of the experiment. One chapter is devoted to the various possible methods of pressure measuring. From among the available methods a pressure measuring system, operating on the principle of induction, was selected for practical realization of a model, and produced in a small series. The experiments pressure ranges of 100, 400 and 800 newton as criteria of interfragmentary compression, were carried out on 20 sheep's metacarpal bones, following osteotomy. During the six weeks experiment, current pressure corrections within a maximum of 10 pc of the nominal pressure were necessary, particularly during the first two weeks. X-ray examination showed with the increase of interfragmentary pressure an ever later beginning and ever less substantial formation of callus, regularily in a process of periosteal formation of callus. The lower the interfragmentary compression became, the earlier and the more frequently resorptive changes in the cortical bone occurred. Findings in the cortical contact areas, obtained microscopically from fluoro-chrome-labelled ground-sections and from corresponding microradiographs, in about half of the cases showed a formation of resorption cavities whose extent increased with the decrease of interfragmentary compression. An effect, observed parallel with this finding and with decreasing interfragmentary compression, was an intensified and earlier bone fill-up reaction. Also Havers' remodelling of the corticalis showed a tendency of increasing with the decrease of interfragmentary compression...

[Investigation of bone growth into porous metal implants (author's transl)]. / Untersuchungen über das Einwachsen von Konchengewebe in poröse Metallimplantate.

Stainless-steel cylinders of different pore size were implanted into the tibia, and small tubes, 500 micrometers diameter, of the same material into the iliac crests of 19 rabbits. It was found that after three weeks ingrowing bone tissue anchored the cylinders if the pore size was adequate. The same applied to the tubes. A stable implantation was the prerequisite for the ingrowth of fibre-bone trabeculae. Additionally, the use of fibrinogen adhesive system seems to be advantageous for this anchorage. These results were established by mechanical tensile tests and morphological examinations.

[Crystallographic investigation of distraction callus (author's transl)]. / Kristallographische Untersuchung des Verlängerungskallus.

Physical examination using electron diffraction and thermogravimetry was performed on the distraction callus of six metacarpal bones of sheep. Brushite was observed in this callus beside apatite, and the number of crystals found was less than in physiological nature bone. From the crystallographic point of view the distraction callus was found similar to the callus known in fracture healing.

[The influence of surgery upon leucocyte function (author's transl)]. / Der Einfluss von Operationen auf Leukozytenfunktionen.

14 patients who underwent a standardized total hip joint replacement were investigated in order to detect postoperative impairment of chemotactic or phagocytic function of their polymorphonuclear leucocytes. A chemotaxis assay in modified Boyden [3] chambers and the nitroblue-tetrazolium assay were used. 25 healthy control persons served for the assessment of normal values and the reproducibility of the respective test. Patients were investigated preoperatively and on the first, third and sixth postoperative day. While phagocytosis remained unchanged throughout the period of investigation, chemotactic leucocyte function was regularly significantly depressed on the first postoperative day. The defect in postoperative chemotaxis might, despite of an unimpaired phagocytic capacity, contribute towards an increased risk of postoperative infections.

[Atelectases as part of the convex-sided lungs in thoracic scoliosis (author's transl)]. / Lungenatelektasen auf der Konvexseite thorakaler Skoliosen.

In 4 patients with juvenile idiopathic thoracic scoliosis an atelectasis as part of the convex-sided lungs was found. In all cases there was a small sagittal diameter of the chest; the atelectases were situated in the right lower and middle lobe and caused by the close topographical relation of large bronchi and scoliotic spine (sometimes compression of the bronchus) demonstrable by tomography, bronchoscopy and bronchography. The therapeutic approach of these atelectases is discussed. Thoracic casting either for conservative correction and treatment of scoliosis or as postoperative immobilisation after fusion was done. In all cases, it may influence the occurrence of an atelectasis.

[Osseous bridging of the distraction gap in leg lengthening procedures (author's transl)]. / Knöcherne Auffüllung des Distriktionsspaltes bei Beinverlängerung

The bony refill of the distraction-space in leg-lengthening operations is analysed by X-ray control and histological technic as well in animal experiments as clinical patients. Based on our observations a theory of the formation of bone is postulated: We figured out, that a) presumable besides the periosteal potentials of bone formation there are also other active mechanisms of bone growth to be found. b) frequently histological recognised formations of bones cannot yet be proved by X-ray, that means, that the X-ray changes follow the histological ones. c) optimal formation of callus needs most possible stability during the time of consolidation. d) most careful distraction prevents deformities.

[Origin and treatment of the socalled "cast syndrome" following operations for scoliosis (author's transl)]. / Zur Entstehung und Behandlung des sogenannten "Cast-Syndroms" nach Skolioseoperationen

Discussion of the causes and treatment of the syndrome called in the literature misleadingly "cast syndrome". Observation of 9 cases who had surgery for scoliosis suggests that the syndrome is largely due to disturbances of function of the innervation of stomach and duodenum.

[The influence of kyphosis on lung function in young scoliotic patients (author's transl)]. / Der Einfluss der Kyphose auf die Lungenfunktion von jungen Skoliosepatienten

By assessment of partial correlation in the field of lung function in kypho-scoliosis, the direct influence of kyphosis on the upward-shift of the mid-respiratory level (FRC% TLC) can be documented. It is shown that several other lung function parameters are dependent more or less on a change of volume balance in the deformed chest and, thus, indirectly on the degree of kyphosis. The degree of scoliosis which was the presenting symptom in our series, shows, of course, a highly significant direct correlation to vital capacity, which in itself is the source of changes in several other lung function parameters. The role of kyphosis in the development of lung function during therapy is being discussed.