D. P. König

Postoperative Analgesia with No Motor Block by Continuous Epidural Infusion of Ropivacaine 0.1% and Sufentanil After Total Hip Replacement

UNLABELLED We assessed the analgesic efficacy of postoperative epidural ropivacaine 0.1% with and without sufentanil 1 microgram/mL in this prospective, randomized, single-blinded study of 30 ASA physical status I-III patients undergoing elective total hip replacement. Lumbar epidural block using 0.75% ropivacaine was combined with either propofol sedation or general anesthesia for surgery. After surgery, the epidural infusion was commenced. Fifteen patients in each group received either an epidural infusion of 0.1% ropivacaine with 1 microgram/mL sufentanil (R + S) or 0.1% ropivacaine without sufentanil (R) at a rate of 5-9 mL/h. All patients had access to i.v. piritramide via a patient-controlled analgesia device. The R + S group consumed six times less piritramide over a 48-h infusion period than the R group (median 12.7 vs 73.0 mg; P < 0.001). Motor block was negligible for the study duration in both groups. Patient satisfaction was excellent. The incidence of adverse events, such as nausea, was similar. We conclude that a continuous epidural infusion of 0.1% ropivacaine with 1 microgram/mL sufentanil is more effective than ropivacaine alone in treating pain after elective hip replacement without motor block. IMPLICATIONS This is the first randomized study comparing the efficacy of the epidural combination of ropivacaine 0.1% and sufentanil 1 microgram/mL versus plain ropivacaine 0.1% in treating pain after hip replacement. We found that ropivacaine 0.1% and sufentanil 1 microgram/mL led to a sixfold reduction in opioid requirements after total hip replacement by producing a negligible motor block.

The effect of computer navigation on blood loss and transfusion rate in TKA.

The blood loss that accompanies total knee arthroplasty (TKA) can be substantial. Many patients need perioperative blood transfusions. To avoid anemia and transfusion-related complications, the amount of blood loss and need for blood transfusions must be reduced. If standard jig instruments are used, an opening of the femoral medullary canal is required. This operative step has been recognized as a reason for elevated blood loss; it is not required if computer navigation is used. Hence, the purpose of this study was to investigate the effect of computer navigation on blood loss and transfusion rate in TKA. The data of 500 consecutive patients undergoing TKA were analyzed, and patient- and operation-related data and blood loss and transfusion rates were recorded. The total blood loss was calculated by use of the Orthopedic Surgery Transfusion Hemoglobin European Overview (OSTHEO) formula. The average blood loss in the drainages (standard procedures, 880 mL; navigated procedures, 761 mL; P=.001) and the calculated total blood loss (standard procedures, 1375 mL; navigated procedures, 1242 mL; P=.036) were significantly reduced in the navigation group. The transfusion rate of navigated procedures was almost halved (standard procedures, 0.23 transfusions/patient; navigated procedures, 0.12 transfusions/patient; P=.035). Our study demonstrated a reduced blood loss if TKAs were implanted by use of computer navigation. The diminished blood loss resulted in a 50% reduction of allogenic blood transfusions. Hence, computer navigation may be attractive for patients with a high risk of transfusions or uncommon blood groups. Prospective studies are required to verify this potential benefit of computer navigation.

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° 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.RésuméLe resurfaçage de la hanche devient de plus en plus populaire. L’optimisation de la position du composant fémoral est importante afin d’éviter les échecs tels que les fractures du col. Matériel et méthode : 60 resurfaçages de hanche ont été analysés de façon rétrospective chez 30 patients en utilisant la même technique avec navigation, sans image et en comparant cette série à une série de 30 patients opérés de façon conventionnelle. La sécurité, la position de l’implant, le temps opératoire et les complications ont été rapportés. Résultats : le système de navigation améliore la position de l’implant de façon significative. Après la courbe d’apprentissage le temps de la navigation augmente de 15 minutes le temps opératoire. Aucune complication n’a été relevée dans les deux groupes. Conclusions : La technique chirurgicale assistée par la navigation permet une meilleure implantation du composant fémoral et évite les erreurs en cas de resurfaçage de hanche. Pour nous, l’amélioration de la position du composant fémoral contrebalance de façon avantageuse l’augmentation du temps opératoire.

Iatrogenic paraplegia in spinal surgery

IntroductionParaplegia as a result of a surgical spinal procedure is a rare complication. The risk cannot be precisely quantified due to the lack of current data. The aim of this study was to record a sufficiently large number of major spinal operations, especially extended methods in scoliosis surgery. Hereby, a reliable statement regarding the risk of severe neurological complications with these surgical techniques should be possible. First, a retrospective analysis of patients from a German spine centre (spinal fusion) and a survey of 17 German centres of spinal surgery were conducted for the retrospective acquisition of severe iatrogenic neurological complications.Materials and methodsThe study included 1194 patients who underwent a spinal fusion during the period 1992–2002. The incidents of postoperative paraplegia are described in detail, and case studies done. Possible causes, methods of intraoperative monitoring and options of therapy are discussed according to research in relevant publications. Additionally, severe neurological complications of 3115 spinal operations were recorded in a standardised survey conducted throughout major German spinal centres.ResultsOf the 1194 patients surveyed, 7 (0.59%) experienced a postsurgical complete or incomplete paraplegia. In 3 of the recorded cases, the cause could be identified. The survey of 3115 scoliosis surgeries showed that iatrogenic paraplegia occurred with a frequency of 0.55%. The risks associated with short spinal fusions (0.14%), cervical discectomies (0.07%) and lumbar discectomies (0.03%) are considerably less.ConclusionOperative treatment of scoliosis with a high degree of correction carries a risk of neurological complications of about 0.5%. Mechanical as well as ischaemic damage to the spinal cord can be detected early by means of consistent intraoperative neuromonitoring.

Treatment of staphylococcal implant infection with rifampicin-ciprofloxacin in stable implants

Abstract Infection following total joint replacement remains a problem that has not been solved so far. The treatment options include removal of the implant and a delayed reconstruction or a direct exchange operation. Among patients with stable implants and short duration of infection as well as in patients who for certain reasons are inoperable, antibiotic therapy with a combination of rifampicin-ciprofloxacin may be a reasonable treatment option for curing staphyloccocal infection without removal of the implant. A case study of a Staphylococcus epidermidis (coagulase-negative) infection following delayed revision total knee replacement after septic loosening of a knee arthroplasty and its successful conservative treatment with rifampicin-ciprofloxacin is described. Alternative rifampicin combinations are discussed with respect to recently developed pharmacodynamical and pharmacokinetical findings of biofilm active drugs.

Antimicrobial substances and effects on sessile bacteria.

Biofilms occur in natural aquatic ecosystems and on surfaces of biomaterials. They are generally associated with clinical infections predominantly of prosthetic hip joints, heart valves and catheters. Sessile microorganisms may be intimately associated with each other and to solid substratum through binding to and inclusion into exopolymer matrices on biofilms. The establishment of functional colonies within the exopolymeric matrices generate physico-chemical gradients within biofilms, that modify the metabolism and cell-wall properties of the microorganism. A consequence of biofilm growth is an enhanced microbial resistance to chemical antimicrobial agents and antibiotics. Investigations on the antimicrobial efficacy of antibiotics, antiseptics and antimicrobial heavy ions, however, gave controversial results. No single antimicrobial substance has been developed for the efficient eradication of adherent bacteria. This review elucidates the mechanisms of microbial resistance in biofilms and strategies for the prevention of biofilm development. Pharmacokinetical and pharmacodynamical issues for the screening of biofilm-active drugs are presented. Combinations of antistaphylococcal antibiotics with rifampin may be advantageous for preventing and curing biomaterial infections.

Besonderheiten der implantatassoziierten Infektion in der orthopädischen Chirurgie

ZusammenfassungDer zunehmende Einsatz von Implantatmaterialien führt zu einem Anstieg des Infektionsrisikos in der modernen Orthopädie. Ist ein Implantatmaterial erst einmal infiziert werden, muss—da die Pathophysiologie dieser speziellen Art von Infektion zu einer relativen Unempfindlichkeit konventioneller Antibiotikatherapien führt—in der Regel das Material explantiert werden. Die Folgen sowohl für den Patienten als auch für unser Gesundheitssystem sind gravierend.Mindestens ein Drittel der Infektionen lässt sich durch striktes hygienisches Arbeiten verhindern. Aufgrund auch geringster Inokulationsmengen als Basis für eine Materialkolonisation und -infektion muss von einem großen Anteil „physiologischer Infektionen“ ausgegangen werden. Deshalb ist die Entwicklung infektionsresistenter Implantatmaterialien eine medizinische Notwendigkeit. Moderne Konzepte solcher Materialien beinhalten antimikrobielle „Drug-delivery-Systeme“, welche in der Lage sind, unphysiologisch hohe Konzentrationen antimikrobieller Substanzen in die Mirkoumgebung des Implantats abzugeben, um damit die phänotypische Resistenz adhärenter Mikroorganismen zu überlisten.AbstractOne of the most important risk factors in orthopedic surgery is implant-associated infection. Adhesion and colonization mediated implant infections are extremely resistant to antibiotics and host defences and frequently persist until the biomaterial or foreign body is removed, which is standard therapy. Tissue damage caused by surgery and foreign body implantation increases the susceptibility to infections, activates host defences and stimulates the generation of inflammatory mediators including radicals that are further aggravated by bacterial activity and toxins.Nearly one third of implant-related infections can be prevented by strictly following established infection control guidelines. However, a significant number of implant-associated infections remains. The escape of bacteria from host defence and antibiotic therapy makes the development of infection-resistant materials as antimicrobial drug delivery systems feasible. This concept consists of the sustained delivery of antimicrobial drugs into the local microenvironment of implants avoiding systemic side effects exceeding usual systemic concentrations by magnitudes of order.

Osteoarthritis and recurrences after Putti-Platt and Eden-Hybbinette operations for recurrent dislocation of the shoulder

Summary. Thirty-five patients who had operations for recurrent anterior dislocation of the shoulder were reviewed, with a further 26 answering a questionnaire; the results were not as good as reported by others. The mean follow up was 26.9 years. Ten out of 43 patients had recurrent dislocations after the Putti-Platt and 6 out of 18 after the Eden-Hybbinette operation. Osteoarthritis developed in 15 shoulders of 26 patients who were followed-up after the former procedure and in 8 out of 9 shoulders after the latter. These sequelae depend on the age at the first dislocation rather than the number of dislocations. The overall satisfaction rate was acceptable for both procedures.Résumé. Notre étude à long terme (sur 61 patients, 35 suivis avec une moyenne de 26,9 ans) montre que les résultats des opérations de Putti-Platt et Eden-Hybbinette pour luxation récidivante de l’épaule ne sont pas, en considérant les récidives et le développement de l’arthrose, aussi bons que ceux rapportés dans la littérature [5, 8, 14, 18]. Dans notre série, 10 patients sur 43 ont eu une luxation récidivante après une intervention de Putti-Platt et 6 sur 18 après une opération de Eden-Hybbinette. Une omarthrose était présente chez 8 sur 9 patients du groupe Eden-Hybbinette et chez 15 sur 26 patients du groupe Putti-Platt. Nous pensons que le développement de l’omarthrose dépend plus de l’âge du patient lors de la première luxation que du nombre de luxation avant l’intervention. Cependant, le taux de succès après une période d’observation moyenne de 26,9 ans était acceptable pour les 2 types de traitement.

In vitro adherence and accumulation of Staphylococcus epidermidis RP 62 A and Staphylococcus epidermidis M7 on four different bone cements.

Abstract. Bacterial resistance of Staphylococcus epidermidis, a serious pathogen of implant-related infections, to antibiotics is related to the production of a glycocalyx slime that impairs antibiotic access and the killing by host defense mechanisms. In vitro studies of different bone cements containing antibiotics, developed for the prevention of biomaterial-associated infection, could not always demonstrate complete eradication of biomaterial-adherent bacteria. We have investigated four different bone cements in regard to bacterial accumulation of a slime-producing strain RP 62 A and its isogenic mutant M7 lacking the ability to produce exopolysaccharide slime using a bacterial adhesion assay and modified Kirby-Bauer technique. A significant effect of exopolysaccharide production for the accumulation on bone cement could be demonstrated. The gentamicin/clindamycin bone cement was the only tested biomaterial that produced a large zone of bacterial inhibition in the inoculated area adjacent to the biomaterial. The bacterial adhesion was not reduced significantly and there was no correlation between zones of inhibition on blood agar plates and the quantitative adhesion assay. The clinical efficacy of the gentamicin/clindamycin bone cement must be proven in vivo.

Osteoarthrosis following the Putti-Platt operation

The objective of this study was to search for any degenerative changes in the shoulder joint following the Putti-Platt operation in a long-term follow-up study, as most papers regarding that operation report a redislocation rate and a limitation of external rotation, but only a few mention osteoarthrosis (OA). Patients operated on between 1945 and 1971 answered a questionnnaire and were invited for a clinical examination including standard X-rays of the shoulder. These films were compared with those taken preoperatively. OA was classified according to the Samilson and Prieto grading. Twenty-six patients could be re-examined on average 26 years after the operation. Fifteen had evident radiological signs of OA. According to Samilson and Prieto there were 11 mild, 2 moderate and 2 severe cases of OA. Nine patients had a Hill-Sachs defect and 3, a Bankart lesion. Patients over the age of 25 years at the time of the first dislocation developed OA more often. Following the Putti-Platt operation one has to expect radiological signs of OA in a longterm follow-up. Mainly minor forms are seen. Older patient age at the time of the first dislocation is a predisposing factor for the development of OA.