On the outcome of computer-assisted total knee replacement.

A number of studies have reported a significant improvement of the postoperative alignment, when computer-navigated total knee arthroplasty (TKA) was compared with conventional techniques. However, no studies are available on the functional and patient-relevant outcomes after computer-assisted knee replacement. In a prospective, randomized trial comparing 27 computer-assisted TKAs with 25 conventional implantations, the Knee Society Score was used to assess functional status, and the WOMAC questionnaire was used to record the disease-specific, patient-relevant outcome. At a twelve-month follow-up no significant difference was detected between the two patient groups in either the scores or the number of complications and range of postoperative knee flexion. The results are in agreement with those reported in other studies on the effect of conventional TKA. With the patient group of this size it can be concluded that computer-navigated TKA gives short-term resuits comparable with those achieved by conventional methods of implantation.

[Total hip arthroplasty in congenital dysplasia of the hip: follow-up of a small-dimensioned, cemented straight stem]. / Hüftendoprothesenimplantation bei Dysplasiecoxarthrose: Follow-up eines kleindimensionierten zementierten Geradschafts.

AIM: The aim of this study is to report the survival and mid-term results including patient-relevant outcome measures with a small-sized cemented stem (CDH-stem) for the treatment of coxarthrosis secondary to developmental dysplasia of the hip. METHOD: 33 total hip replacements were performed with the CDH stem, 29 of which (88 %) were included in the follow-up after an average of 7.6 years. According to the classification system of Hartofilakidis et al., 10 hips were classified as type 1, 15 as type 2, and 3 as type 3. Survival was predicted using Kaplan-Meier survivorship analysis with revision as the end point. Results were assessed using the Harris hip score, as well as the WOMAC and SF-36 as patient-relevant outcome measures. RESULTS: Survival at thirteen years was predicted to be 92.4 % for the stem and 87.6 % for the varying acetabular implants used. At the time of the final follow-up, the average Harris hip score was 82.45 points. The global WOMAC index averaged 2.1, the average SF-36 score was 66.2 points. CONCLUSIONS: The data support the use of a small-sized cemented stem in small femora for total replacement of the dysplastic hip. To the best of our knowledge, this is the first study utilising the well validated WOMAC and SF-36 as patient-relevant outcome measures in this subgroup of patients.

[Postsurgical computed tomography of uncemented hip arthroplasty]. / Postoperative Computertomographie zementfreier Hüftprothesenschäfte.

PURPOSE: Presentation of the value of postsurgical computed tomography (CT) to diagnose loosening of uncemented femoral stems. MATERIALS AND METHODS: Incremental CT and spiral CT were performed on six femora with implanted uncemented stems after the entire femora were embedded in polymethylmethacrylate. The femora were subsequently sectioned (thickness 1 mm, separation 8 mm) and the medial and lateral contact areas of the prosthetic stem compared with the CT data. RESULTS: The CT showed a contact of femoral stem and cortical bone between 0.4 mm (3.4 %) and 4.8 mm (47.1 %) and the section specimens between 0.9 mm (8.7 %) and 3.4 mm (36.7 %). No correlation was found between the results (r = 0.61), since the individual differences were up to 24 % in almost all sections. CONCLUSIONS: Neither single-slice nor two-slice CT is capable of demonstrating the direct bone-endoprosthesis contact. Multidetector row CT (MDCT) is conceivably more accurate to measure the cortical contact of the femoral stem.

The migration of femoral components after total hip replacement surgery: accuracy and precision of software-aided measurements.

OBJECTIVE: To assess the accuracy and precision of a software-aided system to measure migration of femoral components after total hip replacement (THR) on digitised radiographs. DESIGN AND PATIENTS: Subsidence and varus-valgus tilt of THR stems within the femur were measured on digitised anteroposterior pelvic radiographs. The measuring software (UMA, GEMED, Germany) relies on bony landmarks and comparability parameters of two consecutive radiographs. Its accuracy and precision were calculated by comparing it with the gold standard in migration measurements, radiostereometric analysis (RSA). Radiographs and corresponding RSA measurements were performed in 60 patients (38-69 years) following cementless THR surgery. RESULTS AND CONCLUSIONS: The UMA software measured the subsidence of the stems with an accuracy of +/-2.5 mm and varus-valgus tilt with an accuracy of +/-1.8 degrees (95% confidence interval). A good interobserver and intraobserver reliability was calculated with Cronbach's alpha ranging from 0.86 to 0.97. Measuring the subsidence of THR stems within the femur is an important parameter in the diagnosis of implant loosening. Software systems such as UMA improve the accuracy of migration measurements and are easy to use on routinely performed radiographs of operated hip joints.

IL-6 and PGE2 release by human osteoblasts on implant materials.

Regarding orthopaedic implant loosening it has been hypothesized that particle-activated macrophages release interleukin-1 (IL-1) and tumor necrosis factor-alpha (TNF-alpha). This in turn stimulates osteoblasts to release interleukin-6 (IL-6) and prostaglandin E(2) (PGE(2)). These mediators recruit and activate osteoclasts and may therefore lead to bone resorption and loss of implant fixation. In this study we compared the ability of different materials to induce the release of IL-6 and PGE(2) from primary isolated, human osteoblasts without preceding activation by macrophages. We tested stainless steel, cobalt-chromium alloy (CoCrMo), commercially pure titanium (cpTi), Ti-6Al-7Nb and Ti-6Al-4V processed in the same manner as corresponding clinical implants. After 12 and 24h the cells had actively secreted IL-6 and PGE(2). There were no clear differences among the implant materials or with the plastic control. The amount of factors the cells released in our study compare well with the findings of other authors who investigated osteoblasts on plastic. In comparison with the literature these amounts are lower than secretion levels of osteoblasts stimulated with implant particles, IL-1 or TNF-alpha. Moreover, other authors found that osteoclasts require higher concentrations of PGE(2) to become activated than the concentrations measured in our experiments. Therefore, the amount of PGE(2) released from the osteoblasts in our study is probably not sufficient to induce osteolytic activity. Because of contradictory statements in the literature it is unclear if the measured IL-6 concentrations promote osteolytic activity. Differences in material composition does not significantly influence the release of these factors if the materials have similar surface roughnesses.

Surface composition analysis of failed cementless CoCr- and Ti-base-alloy total hip implants.

The surfaces of retrieved failed cementless total hip implants made of cobalt-chromium-molybdenum casting alloy and of wrought titanium 6-aluminum 4-vanadium alloy were studied with the use of scanning-electron microscopy (SEM), energy-dispersive X-ray analysis (EDX) and X-ray photoelectron spectroscopy (XPS). New implants of the same make served as controls. The XPS scans revealed a dense carbon layer on the entire analyzed specimen. The relative composition of the titanium alloy implants showed an overall agreement with the international standards for implants for surgery, and the overall surface composition did not change over the period of the implantation. However, an inhomogeneous distribution of the constituents could be demonstrated in the retrieved as well as in the new MEC-screw rings made of TiAl6V4 alloy, an implant that has been linked to a high early failure rate. In the CoCr-alloy components (Lord-screw rings) a high percentage of aluminum, mainly organized in aluminum inclusions, was found in the retrieved as well as in the new implants.

[Postoperative analgesia--a comparative study in laparoscopic cholecystectomy and lower abdominal laparotomy]. / Postoperative Analgesie--eine vergleichende Studie bei laparoskopischen Cholezystektomien und Unterbauchlaparotomien.

From September 1992 through February 1993 27 randomly chosen female patients were evaluated for differences in postoperative pain intensity (as determined by visual-analogue-scale (VAS)) and analgesic requirements via patient-controlled-analgesia (PCA), either after open lower-abdominal-laparotomy (n = 16, group 1) or after minimal-invasive-cholecystectomy (n = 11, group 2). The type of anaesthesia has been standardized, either as balanced or total intravenous anaesthesia. There were no statistically significant differences between the groups regarding to age, height, weight, intraoperative anaesthetic drug consumption, or duration of anaesthesia and surgery (205.6 vs 185.5 minutes; 139.1 vs 105.0 minutes). All patients could be extubated while still in the operation theatre. The 10-hour study period started after transfer to the recovery room. Heart- and respiratory-rate, systolic/diastolic blood pressure, endtidal pCO2, oxygen-saturation via pulsoxymetry (SaO2), and demands from PCA-pump were recorded, furthermore pain scores were determined every hour. The VAS-scores showed no significant differences between the two groups. The pain level as a whole was low, with the scores ranging from a maximum of 23.4 mm (group 1 after the first hour) to a minimum of 1.8 min (group 2 after 5, 8 an 10 hours). The overall analgesic requirements differed significantly (37.7 vs 17.3 mg piritramid, p < .01). There was a difference throughout the whole study period, although statistically significant only at the 1., 2. (p < .05), 5. and 6.-8. hour (p < .01). This study showed that pain scores were similar after laparoscopic upper or open lower abdominal surgery, both requiring adequate analgesic therapy.(ABSTRACT TRUNCATED AT 250 WORDS)

[Percutaneous liver biopsy in ambulatory patients]. / Die perkutane Leberbiopsie bei ambulanten Patienten.

Percutaneous liver biopsy is a relatively safe procedure. Performance in an outpatient facility is acceptable for many patients. Complications are rare and usually will be recognized within a few hours after biopsy. In most cases, therefore, an observation of six hours is sufficient. Since complications occasionally occur delayed, there must be the possibility to return for hospitalization.

Giant Brunneroma of the duodenum.

A case of giant hyperplasia of Brunner's glands in the duodenum is reported. Recurrent vomiting due to stenosis of the duodenum was the leading symptom. Endoscopy, ultrasound and histological examination were employed as complementary methods to establish the diagnosis. The 5 X 7 cm large tumor was surgically excised. Brunneromas are always benign and their incidence is about 0.08% in upper GI-tract endoscopy.