Serum aluminium and cobalt levels after ceramic-on-ceramic and metal-on-metal total hip replacement.

In a randomised study, 28 patients with a mean age of 62.2 years (32 to 81) with osteoarthritis or avascular necrosis of the hip received either a ceramic-on-ceramic or a metal-on-metal total hip replacement. Apart from the liners the acetabular and femoral components were made of Ti-Al-Nb alloy. The serum aluminium and cobalt levels were measured before, and at one year after surgery. The 15 patients in the ceramic-on-ceramic group had a median pre-operative aluminium level of 1.3 microg/l (0.25 to 8.4) and a cobalt level below the detection limit. At one year the aluminium level was 1.1 microg/l (0.25 to 2.3) and the cobalt level was 0.4 microg/l (0.15 to 0.7). The 13 patients in the metal-on-metal group had a median pre-operative aluminium level of 1.9 microg/l (0.25 to 4.4) and a cobalt level below the detection limit. At one year the median aluminium level was 0.9 microg/l (0.25 to 3.9) whereas the cobalt level was 1.4 microg/l (0.5 to 10.5). This increase in the cobalt level at one year was significant (p < 0.001). Our findings indicate that ceramic-on-ceramic bearings do not cause elevated levels of serum aluminium in the first post-operative year.

[Total hip arthroplasty in Austria. Results of a nationwide survey based on a questionnaire]. / Hüft-Total-Endoprothetik in Osterreich. Eine bundesweite Umfrage mittels Fragebogen.

Besides the number of annual total hip arthroplasty (THA) surgeries (11,978 primary THA, 148 implantations per 10(5) inhabitants), little is known about the state of total hip replacement in Austria. We collected information about different aspects of THA treatment regimens. A questionnaire was developed and sent to all chairmen of orthopedic and traumatology departments posing 22 questions regarding type of THA, surgical technique, number of surgeries, data collection, physical therapy and mobilization, length of hospital stay, and recommendations on sport activities as well as activities of daily life. In Austria cementless THA predominates (according to the questionnaire survey 85%). Postoperative mobilization with cementless implants is prescribed as full weight bearing in 52%, partial weight bearing in 42%, and no weight bearing in 6%. The length of hospital stay with cementless insertion is 14.2 days and with cemented implantation 14.9 days; the use of crutches is recommended for 6.0 and 5.4 weeks, respectively. Hip scores for documentation are used before surgery in 65% of orthopedic departments and 13% of traumatology departments and in the postoperative follow-up in 62% and 13%, respectively. In-patient rehabilitation is prescribed by 74% of orthopedic and 26% of traumatology departments. Austria ranks among the top nations in Europe regarding the number of total hip arthroplasty implantations. Documentation is insufficient and needs to be improved. In some aspects of managing patients with total hip arthroplasties there are remarkable differences between orthopedic and traumatology departments.

Changes in bone mineral density in the proximal femur after cementless total hip arthroplasty. A five-year longitudinal study.

We investigated prospectively the bone mineral density (BMD) of the proximal femur after implantation of a tapered rectangular cementless stem in 100 patients with a mean age of 60 years (16 to 87). It was determined using dual energy x-ray absorptiometry, performed one week after surgery and then every six months until the end-point of five years. The BMD increased significantly in Gruen zones 2, 4 and 5 by 11%, 3% and 11% respectively, and decreased significantly in Gruen zones 1, 6 and 7 by 3%, 6% and 14% respectively, over the five-year period. The net mean BMD did not change over this time period. The changes in the BMD were not confined to the first 12 months after surgery. This investigation revealed no change in the overall periprosthetic BMD, but demonstrated a regional redistribution of bone mass from the proximal to distal zones.

Outcome of osteotomies for the treatment of haemophilic arthropathy of the knee.

BACKGROUND AND AIMS: The knee is one of the most commonly affected joints in haemophilic arthropathy leading to stiffness and disability. It is the aim of this study to investigate the outcome of corrective osteotomies around the knee. PATIENTS AND METHODS: We report on the long-term results of ten osteotomies around the knee for severe haemophilic arthropathy and axial deviation at an average of 7.25+/-1.8 years postoperatively. Seven high tibial (preoperatively 7.2+/-2 degrees varus) and three supracondylar osteotomies (preoperatively 7+/-3 degrees valgus) were performed on seven patients (three of them bilateral). RESULTS: The clinical score of the Advisory Board of the World Federation of Haemophilia (average 7.4 points preoperatively) remained unchanged in two patients, improved in three patients and deteriorated in five patients. The radiological Pettersson score (average 8.2 points preoperatively) showed a worsening of 2.5 points over the time. Patients reported a subjective improvement for seven osteotomies, with sports activity in three patients, although the range of motion did not change significantly. Total knee arthroplasty was considered to be a failure, i.e. endpoint of follow-up. Six knees were replaced in four patients by total arthroplasty after a mean of 6.6 years. CONCLUSION: Although survival of osteotomies around the knee in haemophilic arthropathy is lower than in non-haemophilic patients, we think that it is a choice of treatment, which, at least, postpones the indication for total knee arthroplasty in this young patient group.

[Serum cobalt and serum chromium level in 2 patients with chronic renal failure after total hip prosthesis implantation with metal-metal gliding contact]. / Serumcobalt- und Serumchromspiegel bei zwei chronisch niereninsuffizienten Patientinnen mit Hüfttotalendoprothese und Metall-Metall-Gleitpaarung.

PURPOSE: The influence of chronic renal failure on serum cobalt and serum chromium in two patients with metal-on-metal bearing (Metasul) and cementless total hip arthroplasty (Alloclassic) is investigated. METHODS: Serum cobalt and serum chronium levels were determined in the postoperative course using atomic absorption spectrometry. RESULTS: Maximum values are found to be more than 100-fold elevated when compared to the reported median serum cobalt concentrations in patients with the same prosthesis type and no known renal disease. CONCLUSION: Chronic renal failure seems to be responsible for the marked elevation of serum cobalt and serum chromium. CLINICAL RELEVANCE: Despite evidence of adverse health reactions, a possible effect of long-term cobalt and chromium loading cannot be neglected. In our opinion, metal-on-metal bearings in THA should not be inserted in patients with chronic renal failure. Follow-up investigations (serum cobalt, serum chromium, serum creatinine, BUN, echocardiography) should be performed at short intervals.

Melatonin and adolescent idiopathic scoliosis.

Scoliosis seen in the chicken after pinealectomy resembles adolescent idiopathic scoliosis in man. It has been suggested that in both species, deficiency of the pineal hormone, melatonin, is responsible for this phenomenon. In nine patients with adolescent idiopathic scoliosis and in ten age- and gender-matched controls, the circadian levels of serum melatonin and the excretion of urinary 6-hydroxy-melatonin-sulphate, the principal metabolite of melatonin, were determined. There were no statistically significant differences in the secretion of serum melatonin or the excretion of urinary 6-hydroxy-melatonin-sulphate between the patients and the control group. The hypothesis of melatonin deficiency as a causative factor in the aetiology of adolescent idiopathic scoliosis cannot be supported by our data.

Measurement of urinary melatonin: a useful tool for monitoring serum melatonin after its oral administration.

The relevance of measuring urinary melatonin (MLT) for human pineal research is sometimes questioned, and the relationship among serum levels of MLT, urinary excretion of the unmetabolized hormone, and excretion of MLTs main metabolite, 6-hydroxymelatonin sulfate (aMT6s), is still uncertain. We applied a well established RIA for measuring MLT in serum to urine samples, characterized its criteria of performance in this body fluid, and used it for human studies. In 16 adolescents, the endogenous overnight MLT secretion, expressed as the area under the concentration time curve, correlated significantly with the amounts of urinary aMT6s (r = 0.86; P < 0.0001) and urinary MLT (r = 0.70; P = 0.0027) excreted during a 16-h observation period. Oral administration of 3 mg exogenous MLT in 17 healthy volunteers resulted in peak MLT serum levels differing 28-fold among subjects (940-27,240 pg/ mL; range). In this study urinary MLT, but not aMT6s, excretion was associated with blood MLT concentrations (r = 0.76; P = 0.0004 vs. r = 0.02; P = 0.93, respectively). Thus, endogenous MLT production can be assessed accurately by measuring either aMT6s or MLT excretion. After oral application of MLT, however, only measurement of MLT excretion is a reliable marker of serum concentrations. Determination of MLT in urine may prove to be a useful tool for drug monitoring after oral administration of the pineal hormone.

The postoperative spine.

During the last decade, magnetic resonance imaging (MRI) mostly has replaced computed tomography for evaluation of spinal surgery patients. The inherent advantages of MRI are obvious for this particularly difficult field of imaging. With MRI, it is possible to demonstrate anatomic as well as pathological and iatrogenic changes in three different imaging planes and countless neighboring planes and to obtain a superior view of the complex postoperative situation regardless of the spinal level imaged. Soft-tissue masses in particular can be identified more readily and located within three-dimensional space. One of the major advantages is that the nature and histology of the mass can be estimated precisely using different MR sequences in combination with intravenous contrast media. The most important benefit may be demonstration of inflammatory and hemorrhagic masses in the early postoperative periods (with special emphasis on alterations visible in the spinal cord itself) as well as repair processes and ongoing degeneration in later stages. This visualization is possible even when their extent is limited. In the postoperative spine, the application of MRI was facilitated with the advent of new materials, such as titanium alloys, used for surgical instrumentation. These new materials limit the amount of artifacts visible on MR images. Earlier implants made of other metallic material prohibit the use of computed tomography in the spine. This article provides a brief overview of the progress in spinal surgery and focuses on the developments in MRI techniques during the last decade. Technical questions about imaging of spinal instrumentation are discussed. "Normal" postoperative findings needed for interpretation of pathologic conditions are also discussed. Finally, the most important frequently asked questions from referring surgeons that radiologists must be able to answer by MRI are presented.

Elevated serum cobalt with metal-on-metal articulating surfaces.

We determined serum cobalt levels in 55 patients by atomic absorption spectrophotometry before and after implantation of uncemented total hip arthroplasties. In a randomised, prospective trial 27 wrought Co-28Cr-6Mo-0.2C metal-on-metal articulations were compared with 28 ceramic-on-polyethylene hips which did not contain cobalt. Other sources of iatrogenic cobalt loading were excluded. The metal-on-metal group produced detectable serum cobalt levels (median 1.1 microg/l after one year) which were significantly different (p < 0.0001) from those of the ceramic-on-polyethylene control group (median below detection limit of 0.3 microg/l after one year). Our findings indicate that metal-on-metal bearings generate some systemic release of cobalt.

Clinical and sonographic evaluation of the risk of rupture in the Achilles tendon.

Chronic pain in the region of the Achilles tendon is a common problem and often a sign of progressive degeneration of the tendon which may lead to its rupture. We studied the clinical course and sonograms in 36 patients with achillodynia to find a prognostic parameter enabling us to estimate the risk of rupture. The patients were evaluated clinically for swelling and tenderness and by high-resolution real-time sonography. The sonograms were graded according to the tendon thickness as normal (< 6 mm), minimal (6-8 mm), moderate (8-10 mm) to high-grade (> 10 mm) in the sagittal diameter of the transverse section, and alterations of echotexture were described as diffuse, circumscribed, or inhomogenous. At the time of the primary investigation, we found thickening and alterations of the echotexture in 33 of 72 tendons. In 48 tendons we found pain and local or diffuse swelling in the Achilles tendon region (sensitivity 0.58, specificity 0.79). After a follow-up of 48 +/- 8 months, 7 tendons had ruptured spontaneously. Analysis of the sonograms of the patients taken prior to the rupture showed a high-grade thickening in 4 cases, moderate thickening in 2 cases, and a diameter between 6 and 8 nm in one patient. In no case did we find a rupture of a tendon primarily classified as normal. Patients without sonographic changes exhibited a significantly better clinical outcome following conservative treatment. Sonography was found to be a valuable tool for determination of the tendon's thickness and echotexture. In 28% of our patients with thickening, circumscribed lesions of the echotexture, and chronic pain, a spontaneous rupture occurred.

[Paget's coxarthrosis. Implantation of a modular tumor reconstruction system. Case report]. / Paget-Coxarthrose. Implantation eines modularen Tumor-Rekonstruktionssystems. Fallbericht.

A male patient aged 69 years suffering from Paget-coxarthrosis with a large distension of the proximal femur was implanted a cementless tumor reconstruction system. The surgical procedure consisted of opening of the femoral shaft with a special drill, insertion of the prosthesis and its anchorage within the healthy distal bone. By this method we were able to save the femoral muscle insertion planes. Twenty-eight months postoperatively the patient is pain-free and very satisfied with the outcome. The X-rays show a good fit of the prosthesis. The Harris Hip Score is now 90.1 points as compared to 46.4 points preoperatively.