[Computer-assisted joint replacement surgery]. / Navigation in der Endoprothetik.

Wrong alignment of hip and knee prosthesis is a known risk factor for early loosening and revision. Meta-analyses have shown that, by use of computer navigation, outliers can be reduced significantly. Our analysis of 200 implanted knee prostheses (100 navigated procedures, 100 conventional procedures) and 60 implanted hip resurfacings (30 navigated procedures, 30 conventional procedures) yielded the same result: In total knee arthroplasty and hip resurfacing, the numbers of outliers were significantly reduced by use of computer navigation. Furthermore, in total knee arthroplasty a significantly reduced blood loss and need for blood transfusions were noted if computer navigation was used. Long term studies are required to verify if computer navigation may be an economically cost-saving procedure. So far, in our clinic every navigated operation produced extra costs of 442 Euros. In our current healthcare system no reimbursement for these additional charges exist.

How accurate is image-free computer navigation for hip resurfacing arthroplasty? An anatomical investigation.

BACKGROUND: The existing studies concerning image-free navigated implantation of hip resurfacing arthroplasty are based on analysis of the accuracy of conventional biplane radiography. Studies have shown that these measurements in biplane radiography are imprecise and that precision is improved by use of three-dimensional (3D) computer tomography (CT) scans. To date, the accuracy of image-free navigation devices for hip resurfacing has not been investigated using CT scans, and anteversion accuracy has not been assessed at all. Furthermore, no study has tested the reliability of the navigation software concerning the automatically calculated implant position. The purpose of our study was to analyze the accuracy of varus-valgus and anteversion using an image-free hip resurfacing navigation device. The reliability of the software-calculated implant position was also determined. METHODS: A total of 32 femoral hip resurfacing components were implanted on embalmed human femors using an image-free navigation device. In all, 16 prostheses were implanted with the proposed position generated by the navigation software; the 16 prostheses were inserted in an optimized valgus position. A 3D CT scan was undertaken before and after operation. RESULTS: The difference between the measured and planned varus-valgus angle averaged 1 degrees (mean +/- SD: group I, 1 degrees +/- 2 degrees ; group II, 1 degrees +/- 1 degrees ). The mean +/- SD difference between femoral neck anteversion and anteversion of the implant was 4 degrees (group I, 4 degrees +/- 4 degrees ; group II, 4 degrees +/- 3 degrees ). The software-calculated implant position differed 7 degrees +/- 8 degrees from the measured neck-shaft angle. These measured accuracies did not differ significantly between the two groups. CONCLUSIONS: Our study proved the high accuracy of the navigation device concerning the most important biomechanical factor: the varus-valgus angle. The software calculation of the proposed implant position has been shown to be inaccurate and needs improvement. Hence, manual adjustment of the implant position in the software-planning step is frequently required.

Imageless navigation of hip resurfacing arthroplasty increases the implant accuracy.

Surface arthroplasty of the hip is increasingly popular. Optimising the position of the femoral component is essential to avoid early implant failures such as femoral neck fractures. Sixty hip surface replacements were retrospectively analysed. In 30 patients imageless navigation was used, and 30 patients were operated upon using conventional jigs. Accuracy, implant position, operating time, and complications have been recorded. The navigation device improved the implant position with high accuracy. Implant-shaft angles <130 degrees and uncovered cancellous bone of the superior femoral neck could be safely avoided. After a significant learning curve, navigation took 15 minutes longer than conventional implantation. No complications were found in either group. Computer-assisted navigation allowed accurate implantation of the femoral component avoiding pitfalls of hip surface replacement. From our point of view the optimal placement of the femoral component outweighs the disadvantage of a longer operating time.

[Injuries to the upper limbs in competitive wrestlers]. / Verletzungen der oberen Extremitäten bei Ringern im Hochleistungssport.

Great variety of tackling and defence in wrestling in standing position and on the floor cannot be compared to other kind of sports. High demand to motoric characteristics and tournament specific movability is required. However wrestling in Germany belongs to a fringe sport there is an increase of professionality. This leads to a sufficient and high-demanded supervision. Aim of this retrospective study was to evaluate sport injuries using a questionnaire and to figure out a correlation between kind and frequency of sport injuries of different body regions. 163 questionnaires out of 200 had been evaluated. In the region of the upper limb injuries had been found in 23%. The injury rate was higher in the athletes wrestling in the 2nd league. Wrestling is a technically and tactically ambitious sport. Injuries should be evaluated very careful to minimize the risk changing tactics and training methods.

[Students evaluation of a sports-orthopaedic and sports-traumatological course in theory and practice]. / Evaluierung eines sportorthopädisch-sporttraumatologischen Studentenkurses in Seminar- und Praxisform.

Sports traumatology and sports orthopaedics are two closely interconnected fields usually more or less non-existent in a medical curriculum. Optional courses are difficult to coordinate because of the densely packed course schedule of a medical student, although the overall interest in it shows a continually upward trend. The course that is being offered since the winter semester 2004 / 2005 has been conceived as a seminar with lectures on a variety of subjects but it contains a practical part as well, e. g. for improving examination techniques. The offered course is particularly aimed at students of higher clinical semesters. The evaluation was carried out using questionnaires that were designed especially for this purpose. Subject to evaluation were not only general topics, but also the course instructors who had participated in the theoretical and practical implementation of the course. Suggestions for improvement or other comments were encouraged and taken into consideration. A total of 116 medical students (m = 68, f = 48) who have taken the course since the winter semester 2004 / 2005 have answered the questionnaire for the present evaluation. The interdisciplinary topics, covered the theoretical as well as the practical ones, were considered as interesting and important by 90 % of the students, organization and commitment on the part of the instructors were largely commended. Additional training in sports orthopaedics and sports traumatology enjoys great popularity on the part of medical students, in spite of their densely packed course schedule. Especially its multidisciplinary orientation provides students with a general overview in sports orthopaedics and sports traumatology and raises further interest in both fields of study.

[Interspinous decompression as treatment for lumbar spinal stenosis]. / Interspinöse Dekompression als Therapie der lumbalen Spinalkanalstenose.

Interspinous process distractors are an effective operative tool for treating patients with lumbar spinal stenosis. Lumbar stenosis with minor secondary instabilities due to degenerative changes in the segment can also be treated successfully with these devices. In case of failure, these devices can easily be revised or removed. As this operative procedure is not very time-consuming, it is a reasonable option for elderly patients with various medical problems and increased anaesthetic risk. There are reports of implanting these devices in certain cases under local anaesthetic. A prospective randomised trial has shown promising results for up to two years postoperatively. There are no long-term results available.

[Dynamic ultrasound examination of the shoulder of golf players]. / Dynamisch-sonographische Untersuchung der Schulter beim Golfspieler.

Although golf is becoming popular it can result in injury, usually from overuse and from poor technique. The shoulder is a commonly affected site, with the lead shoulder (or the left shoulder in the right-handed golfer) vulnerable to injury. With this study we tried to figure out any hyperlaxity of the lead shoulder using ultrasonography. 33 golf-players were investigated by questionnaire, clinical examination and dynamic ultrasonography. Neither clinically nor by using ultrasonography hyperlaxity of the shoulder was found. Nevertheless hyperlaxity followed by secondary impingement should be considered.

[Distal soft-tissue procedure in hallux valgus deformity]. / Distaler Weichteileingriff am Großzehengrundgelenk bei Hallux-valgus-Deformität.

OBJECTIVE: Distal, lateral soft tissue release to restore mediolateral balance of the first metatarsophalangeal (MTP) joint in hallux valgus deformity. Incision of the adductor hallucis tendon from the fibular sesamoid, the lateral capsule, the lateral collateral ligament, and the lateral metatarsosesamoid ligament. INDICATIONS: Hallux valgus deformities or recurrent hallux valgus deformities with an incongruent MTP joint. CONTRAINDICATIONS: General medical contraindications to surgical interventions. Painful stiffness of the MTP joint, osteonecrosis, congruent joint. Relative contraindications: connective tissue diseases (Marfan syndrome, Ehler-Danlos syndrome). SURGICAL TECHNIQUE: Longitudinal, dorsal incision in the first intermetatarsal web space between the first and second MTP joint. Blunt dissection and identification of the adductor hallucis tendon. Release of the adductor tendon from the fibular sesamoid. Incision of the lateral capsule, the lateral collateral ligament, and the lateral metatarsosesamoid ligament. POSTOPERATIVE MANAGEMENT: Postoperative management depends on bony correction. In joint-preserving procedures, dressing for 3 weeks in corrected position. Subsequently hallux valgus orthosis at night and a toe spreader for a further 3 months. Passive mobilization of the first MTP joint. Postoperative weight-bearing according to the osteotomy. RESULTS: A total of 31 patients with isolated hallux valgus deformity underwent surgery with a Chevron and Akin osteotomy and a distal medial and lateral soft tissue balancing. The mean preoperative intermetatarsal (IMA) angle was 12.3° (range 11-15°); the hallux valgus (HV) angle was 28.2° (25-36°). The mean follow-up was 16.4 months (range 12-22 months). The mean postoperative IMA correction ranged between 2 and 7° (mean 5.2°); the mean HV correction was 15.5° (range 9-21°). In all, 29 patients (93%) were satisfied or very satisfied with the postoperative outcome, while 2 patients (7%) were not satisfied due to one delayed wound healing and one recurrent hallux valgus deformity. There were no infections, clinical and radiological signs of avascular necrosis of the metatarsal head, overcorrection with hallux varus deformity, or significant stiffness of the first MTP joint.

[Isokinetic testing of the shoulder of handball players]. / Isokinetische Messungen der Handballer-Schulter.

Aim of the study was to evaluate an isokinetic profile testing handball players to describe muscular imbalance. 30 athletes (15 male and 15 female) were measured at the Cybex 6000 test-unit for concentric internal and external rotation. Both shoulders, throwing arm (dominant shoulder) and the opposite shoulder were tested by speeds at 60 degrees/s and 180 degrees/s. There were sex specific differences which are also found in other sports. But these contrary data are not useful to define effective training concepts for handball-players with shoulder problems. From our point of view isokinetic testing of the shoulder joint in handball players can not reach any sufficient result. From our point of view there is no reason for using isokinetic testing to evaluate shoulder problems.

[Intradiscal electrothermal therapy (IDET)]. / Intradiskale elektrothermale Therapie (IDET).

Low back pain is a major physical and socioeconomic problem. A significant percentage is attributable to internal disc disruption (IDD). The management of IDD has been limited to conservative treatment or to operative treatment. Intradiscal electrothermal therapy (IDET) is a new minimal-invasive therapy. In carefully selected patients, it could be an effective treatment alternative. Further studies with long-term follow-up are necessary.

Pharmacokinetics of the antimicrobial agents rifampicin and miconazole released from a loaded central venous catheter.

The time course of rifampicin and miconazole concentrations after insertion of a polyurethane catheter loaded with these antibiotics were studied. Data from controlled release experiments in vitro were used, and the concentration time courses of the antimicrobials in serum were calculated by pharmacokinetic simulations. Systemic therapy using typical dosages (rifampicin 600 mg/day iv, miconazole 3 x 200 mg/day iv) results in rifampicin concentrations between 54 and 8424 microg/L, and miconazole concentrations between 3567 and 4676 microg/L. After insertion of a polyurethane catheter loaded with these antibiotics, the maximal concentrations after catheter placement were determined as 6 microg/L at 10.7h for rifampicin, and 13 microg/L at 28.6 h for miconazole. Assuming that the total amount of antibiotics incorporated in the catheter matrix were bioavailable ('worst case'), the resulting maximal concentrations calculated by simulation are 10 microg/L for rifampicin and 65 microg/L for miconazole. Maximal concentrations of rifampicin or miconazole resulting from the insertion of a polyurethane catheter loaded with these antibiotics are, therefore, far below the concentrations resulting from a systemic therapy with the same antimicrobial agents. Even in the worst case, the danger of selecting resistant bacterial strains seems remote because the systemic drug levels are magnitudes of order below subinhibitory concentrations.

Cryosurgery in long bones with new miniature cryoprobe: an experimental in vivo study of the cryosurgical temperature field in sheep.

AIM: The aim of this in vivo study was to determine whether new miniature cryoprobes provide adequate tissue cooling in long bones by measuring the field of temperature under various conditions. METHODS: Freezings were performed in femoral and tibial bones of 10 sheep under general anaesthesia. Applying one cryoprobe, temperatures of -75 degrees C resp. -51 degrees C could be reached within 0.75 cm resp. 1.00 cm of the probe. RESULTS: Histological examinations revealed compact bone and marrow necroses along the isotherm in all 10 sheep. Using two cryoprobes simultaneously, a mean temperature decrease to -71 degrees C between the two cryoprobes was achieved thanks to the synergistic freezing effect. Looking at consecutive freezes, it was apparent that with similar cryoprobe end temperatures, the temperature dropped faster if the number of freezing cycles was increased. CONCLUSION: In conclusion, it was seen that despite its small diameter, the new miniature cryoprobe delivers adequate in vivo tissue cooling in long tubular bones. Employing the synergistic freezing effect by using two or more cryoprobes simultaneously, efficient in vivo freezing of larger bone segments is also possible. Thus, cryosurgery with the new miniature probes can provide a valuable complement to conventional resection of long tubular bones, and offers a viable alternative to surgical treatment of neoplastic diseases of the skeletal system.

[Development of ultrasonography in a radiological university department from 1994 to 2001]. / Entwicklung der sonographischen Diagnostik in einer Radiologischen Universitätsklinik von 1994 bis 2001.

BACKGROUND: In 1994, 5 % of a total of 25 718 examinations and 7 % of all 4630 B-mode sonograms performed in the Radiology Department, University of Cologne was classified as not indicated. In light of these results, the health care policy guidelines for sonographic indications have been amended. PURPOSE: The aim of this study was to establish the current rate of non-indicated sonographic examinations performed in routine diagnostics by radiology departments at university hospitals, to determine the reasons for such over-diagnosis and identify which regulatory mechanisms can be implemented to prevent his. METHOD: We counted the number of 1) B-mode and 2) color-flow Doppler ultrasound imaging procedures carried out in patients who had had no change in symptoms within the previous 4 weeks or who were scheduled without reference to an existing sonogram (double examinations). 3) The reasons for over-diagnosis were analyzed. 4) The 1994 survey was repeated in 2000 with an identical protocol and 5) additionally, a modified survey of the diagnostic questions was conducted. RESULTS: 1) Out of 4,119 patients presenting for the first time to receive a B-mode sonogram, 443 prior sonograms (11 %), 305 CT scans (7 %) and 57 MRI scans (1 %) were documented. 2) Double sonograms were carried out in 6 % of the 1,118 patients presenting for the first time for color-flow Doppler ultrasounds and in 16 % of the 651 patients assigned to receive catheter angiographies with arterial color-flow Doppler. 2) 41 out of 55 (75 %) prior sonograms from non-university settings stated by 94 surgery patients were listed in the medical records. 36 out of 43 (84 %) prior sonograms from the university hospital were repeated in the same patients despite the fact that the medical report with the findings was available. None of the 48 sonograms indicated to confirm a plausible finding yielded any information that was additionally relevant to therapy. 4) In the period April - June, 2000, 12 % of all 15,921 tests and interventions, 26 % of 3,569 B-mode sonograms and 58 % of 1,033 abdominal sonograms performed in adults were classified as having not been indicated. 5) Staging and follow-up were stated as the most common reasons that a sonography was carried out in 46 % of the 1,017 adults who were given B-mode sonograms conducted from Jan - Mar, 2000 and comprised 62 % of the 410 sonograms classified as not or probably not medically indicated. CONCLUSION: The results showed that a multidisciplinary consensus was required to establish the diagnostic value of sonographic procedures. Therefore, this research group drafted a hospital-internal interdisciplinary guideline for "abdominal transcutaneous B-mode sonography in oncological questions".

Novel strategies to prevent catheter-associated infections in oncology patients.

Aggressive cytotoxic treatment of cancer contributes to the growing number of life-threatening infections. Vascular catheters create predominant risks for staphylococcal, enterococcal and candida blood stream infections. Although the contaminating microorganisms may be few in number, the altered host immune response in the presence of such implants as well as disease-associated immunosuppression implies that even small bacterial counts have to be regarded as highly virulent species. Diagnosis of catheter-related infection (CRI) remains difficult before withdrawal of the suspected catheter. Positive culture of catheter surface, lumen and hub and positive peripheral blood probes (paired quantitative blood culture) are predictive for catheter related bacteremia (CRB). Diligent catheter care and effective antimicrobial catheters may reduce prolonged hospital stay, increased morbidity or mortality and serious economical consequences. The most promising approach features the incorporation of antimicrobial drugs into the polymer matrices that entrap but do not bind the drugs, allowing for extended release. For the efficacious prevention of colonization in the microenvironment of the implantable device the concentration of the antimicrobial substances must exceed usual antibiotic concentrations by a thousand-fold. This is the desired effect--high concentration near the device surface and very low systemic concentration. Incorporation of antimicrobials in the bulk material that constitutes a device can be effective as shown in several in vitro and in vivo studies. In the future, modification of both short-term and long-term catheters by biofilm-active antimicrobials creating slow delivery systems may provide an effective method to protect patients from nosocomial infection in oncology.

[Pioneers in the lengthening of the extremities]. / Pioniere der Extremitätenverlängerung.

Successful lengthening of the extremities was first published at the beginning of the twentieth century. Those reports in which methods such as the distraction of fragments, callus or epiphysis were mentioned for the first time are reviewed. Lengthening of the extremities by epiphyseal distraction was first mentioned by Bernhard v. Langenbeck in 1869 in an animal experiment. The publications of Codivilla, who introduced lengthening by fragment distraction, Kirschner, Bier and others are cited and analyzed critically. Thus, the historical development of the lengthening of the extremities is reported from 1869 to the middle of the twentieth century.

[Injuries and muscle tightness in soccer]. / Verletzungen und Muskelverkürzungen im Fussballsport.

Soccer is one of the most popular sports worldwide. Due to its characteristic many injuries are expected. Muscular tightness is postulated as an intrinsic risk factor for the developement of a muscle injury. Muscle flexibility testing can identify soccer players at risk for musculoskeletal lesions. One-hundred-and-seventeen male amateur soccer players aged 4 to 29 were examined for former injuries and muscular flexibility by using Janda's "functional muscular diagnostic". Muscle injuries and ankle lesions predominated among the injuries. The "functional muscular diagnostic" is suitable for screening muscular flexibility in soccer players. You found comprehensive muscular tightness among the soccer players. The value of stretching for preventing exercise-related muscle injury is still unclear.

[Clinical examination of the shoulder]. / Die klinische Untersuchung der Schulter.

The shoulder examination technique as described by the authors helps to come to the diagnosis mostly without the help of apparative techniques. The described examination techniques are well established and have been used successfully by the authors.

[Autologous chondrocyte transplantation--progress or misleading development in high-tech medicine?]. / Autologe Chondrozytentransplantation--Fortschritt oder Irrweg der Hightech-Medizin?

Autologous chondrocyte transplantation (ACT) is a recently developed procedure for repairing chondral defects of the knee. An analysis of the literature provides no evidence so far for regular regeneration of hyaline cartilage, and no randomized controlled studies are available showing a long-term efficacy. Therefore, controlled randomized studies are urgently needed. At present, ACT cannot be recommended for extended application in clinical practice.

[Development of physical and sports activity in patients before and after implantation of a total knee endoprosthesis. A prospective study of 40 patients]. / Entwicklung der körperlichen und sportlichen Aktivität von Patienten vor und nach Implantation einer totalen Knieendoprothese. Eine prospektive Studie an 40 Patienten.

AIM: The aim of this prospective study was to analyse the development of activities of daily living (ADL) as well as sports activities in patients suffering from osteoarthritis of the knee and undergoing total knee replacement. 40 patients with 42 operated knee joints were included in this study. METHOD: 38 patients (40 knee replacements) recieved a PFC endoprosthesis, 2 patients recieved a GSB endoprosthesis. In 28 cases (71%) we found generalized degenerative joint changes, in 7 cases (17%) a varus deformity and in 2 cases (5%) a valgus deformity. Post-traumatic osteoarthritis was seen in 3 cases (7%). We used the PFC endoprosthesis in patients with stable ligaments, in unstable joints we used the GSB endoprosthesis. Patients were reviewed clinically and radiographically and answered a questionnaire with special reference to ADL (walking, gymnastics, bicycling, homework, swimming, gardening). For evaluation of the results we used the Ranawat & Shine score. Pain was determined with the VAS (visual analogue pain scale). RESULTS: The activity level increased from preoperatively 62.5% up to 91.5% 2 years postoperatively. This was mainly due to walking and gymnastics. Overall sports activities decreased. There was a high uncertainty regarding activities due to patients' lack of knowledge about possible postoperative load capacity of the new joint. The average score according to Ranawat & Shine increased from preoperative 56.98 to 75.89 points out of 100. Most significantly we found an improvement in the pain rating. There was an improvement of 73% under resting and of 81% under activity conditions. CONCLUSION: With this prospective study we can demonstrate the benefit for patients undergoing knee replacement surgery with respect to activities of daily living and especially pain reduction.