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Background: Internal fixation of displaced intraarticular calcaneal fractures in patients older than 50 years remains controversial. This is, in many cases, due to fear of loss of fixation and the risk of implant failure in osteoporotic bone. It is the objective of this study to compare the fixation strength obtained using calcaneal plates with and without locking screws, in the fixation of osteoporotic cadaveric intraarticular calcaneal fractures., Methods: In seven pairs of fresh frozen lower limbs cadavers, intraarticular calcaneal fractures were created with a dynamic single impact loading device and stabilized using either the low profile locking plate, or the conventional calcaneus plate. Radiographs were obtained to assess reduction. The specimens were then subjected to cyclic loading followed by loading to failure, using matched pairs of cadaveric lower limbs. The Wilcoxon signed rank test was used to test for differences in the results., Findings: The locking plate showed a significant lower irreversible deformation during cyclic loading and a significant higher load to failure. The difference between the ultimate displacement, and work to failure was not significant. A low bone mineral content in the area of the posterior facet correlated only in the conventional plate group with increased irreversible deformation., Interpretation: This study supports the mechanical viability of using locking calcaneal plates for the fixation of intraarticular calcaneal fractures in elderly patients.

Purpose: To compare the stability and stiffness of dorsal and volar fixed-angle distal radius constructs in a cadaveric model., Methods: A locking distal radius system was used in a combination of a dorsal and styloid plate (group 1), a single volar plate (group 2), and a combination of a volar and styloid plate (group 3) configuration. In addition a single volar 3.5-mm steel locking plate was used in group 4. Each construct was tested on 6 fresh-frozen radii with simulated unstable dorsally comminuted extra-articular distal radius fractures. Specimens were tested on a material testing machine with an extensometer and subjected to axial compression fatigue and load-to-failure testing., Results: No construct failed in fatigue testing of 250 N for 5,000 cycles. Two specimens in each group were tested for 20,000 cycles without failure. The plastic deformation in the double-plate groups was lower compared with the single-plate groups, although the difference was not statistically significant. Group 1 had the highest and group 4 the lowest failure load and stiffness, respectively. The differences between group 1 and the other groups, except failure load compared with group 3, were statistically significant. Groups 2 and 3 had a significantly higher load to failure and group 3 had a significantly higher stiffness compared with group 4., Conclusions: All constructs offer adequate stability with minimal deformation on fatigue testing under physiologic conditions. Dorsal fixed-angle constructs are stiffer and stronger than volar constructs. The addition of a styloid plate to a volar plate did not significantly improve stability in this model of simulated extra-articular dorsal comminution loaded in axial compression.

Pesticide residues continue to be the focus of many environmental studies, and the number of articles describing the development of more advanced, multiresidue analytical methodologies does not decline. The use of liquid chromatography-mass spectrometry based on single quadrupole or ion trap analyzers is consolidated for this purpose. The implementation, in the near future, of more sophisticated mass analyzers, such as triple quadrupole and hybrid quadrupole-time-of-flight is anticipated for routine analysis. This article reviews the various works published so far in the literature for the determination of pesticides and transformation products (TPs) in water by means of liquid chromatography (LC) coupled to tandem mass spectrometry. It discusses the various ionization sources and analyzers used for this purpose, as well as the extraction procedures employed for previous sample preconcentration. Because of the widespread use of triple quadrupole analyzers for the generation of pesticides levels in water using tandem mass spectrometry, a table compiling the transitions monitored for ca. 70 compounds is also included., ((c) 2006 Wiley Periodicals, Inc.)

Like no other joint of the human body the knee depends on intact ligaments. Knee instability due to ligament injuries will cause abnormal joint kinematics, and thereby is made responsible for secondary damage to other important knee joint structures. Diagnosis of knee ligament injuries is based on the detailed history with often typical injury patterns, as well as on the physical examination with specific knee ligament tests. In addition radiological evaluation is used. The range of knee ligament injuries is wide. Beginning with an isolated medial collateral ligament rupture which will heal with conservative treatment, they range to knee dislocation, a serious injury which needs emediate care and is associated with a high incidence of complications. Surgical procedures aim to reconstruct knee ligaments as anatomical as possible to provide for a long term stable knee joint.

Calcific tendinitis at the femoral insertion of the glutaeus maximus tendon is an unusual but well-described location for an ossifying enthesopathy. Extracorporeal shock-wave lithotripsy has become a standard therapy for various pathologies in orthopaedics. We report a case of a 50-year-old man with painful calcific tendinitis at the femoral insertion of the glutaeus maximus tendon who successfully underwent extracorporeal shock-wave treatment.

In this work four different commercially available enzyme-linked immunosorbent assays (ELISA) (from Japan EnviroChemicals, Ltd., Tokyo, Japan) were evaluated in terms of performance for the rapid screening of estrogens in different water matrices, including natural and spiked samples from urban wastewater, river water and ground water. All four test kits are based on monoclonal antibodies. The compounds detected by these immunoassays are (1) 17-beta-estradiol, (2) estrone, (3) 17-alpha-ethynyl estradiol and (4) estrogens in general, with high recognition properties for 17-beta-estradiol, estrone and estriol. Standards were prepared in water containing 10% (v/v) methanol. The IC50 (corresponding to the 50% of the effective concentration) values, the dynamic ranges, and the limits of detection of the ELISA kits were 0.060-0.304 microg/L, 0.05-5 microg/L and 0.05 microg/L, respectively. All samples were extracted by solid-phase extraction (SPE) beforehand, and the evaluation was carried out by comparing the results obtained by ELISA with those obtained by HPLC-MS/MS using a triple quadrupole (QqQ) instrument. In addition, two different solid-phase extraction procedures were carried out and compared. Except for moderate overestimation in the results observed with the ELISA kits in the analysis of complex wastewater samples, the results obtained using all of the tested techniques were generally in very good agreement.

Objective: To determine the biomechanical properties of different fixation methods for high tibial medial opening wedge osteotomy in order to determine appropriate surgical and rehabilitation guidelines., Design: A biomechanical testing examined the construct stiffness and the fixation strength of two different plates., Background: Although medial opening wedge techniques for high tibial osteotomies have become popular in recent years, biomechanical data of frequently used implants is lacking., Methods: A 15-mm medial opening gap was stabilized in each of eight medium composite tibial bones either with the modified Arthrex Osteotomy Plate (Puddu Plate) or the TomoFix Plate., Results: Both constructs failed under compression and torsion at the lateral cortex and occurred at higher maximal forces by using the TomoFix Plate. After fracture of the lateral cortex the axial stiffness was reduced by 47% and the torsional rigidity by 54% for the TomoFix. For the Puddu Plate these reductions were 66% and 78%, respectively. The differences between the two groups were significant in all conducted tests (P < 0.05)., Conclusions: This study indicates that an unharmed lateral hinge largely dictates the stability after high tibial osteotomy. If the lateral cortex is injured, the TomoFix plate provides superior stability in both compression and torsion compared to the Puddu Plate. In the latter case additional fixation might be considered., Relevance: These biomechanical tests helped to identify clinical situations in which the mechanical attributes of the plates would prove advantageous.

Objective: To test the hypothesis that oblique screws at the ends of a plate provide increased strength of fixation as compared to standard screw insertion., Design: Biomechanical laboratory study in synthetic bone test medium., Methods: Narrow 4.5-mm stainless steel low-contoured dynamic compression plates were anchored with cortical screws to blocks of polyurethane foam. The fixation strength in cantilever bending (gap closing mode) and torsion was quantified using a material testing system. Different constructs were tested to investigate the effect of the screw orientation at the end of the plate (straight versus oblique at 30 degrees), the plate, and bridging length as well as the number of screws., Results: An oblique screw at the plate end produced an increased strength of fixation in all tests; however, the difference was more significant in shorter plates and in constructs with no screw omission adjacent to the fracture site. Both longer plates and increased bridging length produced a significantly stronger construct able to withstand higher compression loads. Under torsional loading, the fixation strength was mainly dependent on the number of screws., Conclusions: The current data suggest that when using a conventional plating technique, plate length is the most important factor in withstanding forces in cantilever bending. With regard to resisting torsional load, the number of screws is the most important factor. Furthermore, oblique screws at the ends of a plate increase fixation strength., (Copyright 2004 Lippincott Williams & Wilkins)

Many patients would like to resume some sport activities after total knee replacement; however, most recommendations are based on subjective opinion rather than scientific evidence. The following paper presents a literature review of sports after total knee replacement and includes recommendations which are based on biomechanical laws. Most total knee designs show increased conformity near full extension. Beyond a certain knee flexion angle, the conformity ratio decreases due to a reduced femoral radius. Therefore, these designs accept higher loads near full extension than in flexion. In order to recommend suitable physical activities after total knee replacement, both the load and the knee flexion angle of the peak load must be considered. It has been shown that power walking and cycling produce the lowest polyethylene inlay stress of a total knee replacement and seem to be the least demanding endurance activities. Jogging and downhill walking show high inlay stress levels and should be avoided. Hence, for mountain hiking, patients are advised to avoid descents or at least use skipoles and walk slowly downhill to reduce the load on the knee joint. It must also be mentioned that any activity represents additional wear, which may affect the long-term results of total knee replacements. Further clinical studies are necessary to validate the biomechanical investigations.

The effects of different conformity ratios and loads on the ultrahigh molecular weight polyethylene stress levels acting on knee implants were examined using a nonlinear, finite element analysis. The contact condition between a rigid cylinder with a radius of 30 mm and a polyethylene plate was modeled. Nonlinear behavior of polyethylene was assumed. The polyethylene plate was constructed with varying radii, with a minimal thickness of 6 mm and with a width of 40 mm. The ratio of the cylinder radius to the radius of the polyethylene plate was defined as the conformity ratio; a conformity ratio of 0 represented a flat tibial inlay, whereas the highest ratio modeled of 0.99 was nearly conforming. The conformity ratios modeled were 0, 0.2, 0.4, 0.6, 0.7, 0.8, 0.9, 0.95, and 0.99. The loads applied were 1000 N, 2000 N, 3000 N, 4000 N, 5000 N, and 6000 N. The effects of different conformity ratios and loads on the contact area (mm2), the compressive surface stress (MPa), the shear stress (MPa), and the von Mises stress (MPa) were investigated. It was found that all of these parameters were affected by changes to the conformity ratio and to a lesser extent by load changes. That is, increasing the load from 3000 N to 6000 N resulted in a surface and shear stress increase lower than the increase in stress caused by the small change of the conformity ratio from 0.99 to 0.95. The effect of an increasing conformity ratio on the reduction in stress was more pronounced for conformity ratios above 0.8. In addition, the effect of a load increase for a flat tibial inlay was two times greater than for one with near full conformity.

Purpose: No biomechanical evaluation of total knee designs exists for loads occurring during sports activities. It was the purpose of the present study to evaluate the contact stress distribution and contact area of different knee joint designs for loads that occur during four common recreational endurance activities., Methods: Three different total knee designs were evaluated for loads occurring during cycling (1.2 body weight (BW) at 80 degrees of knee flexion), power walking (4 BW at 20 degrees), hiking (8 BW at 40 degrees), and jogging (9 BW at 50 degrees) using Fuji pressure-sensitive film. The designs consisted of a flat tibial inlay, a curved inlay, and an inlay with mobile bearings. Five measurements were conducted for each load. The pressure sensitive films were scanned and analyzed using an image analysis program., Results: During cycling, the area with stress levels above the yield point of polyethylene (overloaded area) was below 15 mm2 for each design. During power walking, the mobile bearing design showed no overloaded area, whereas it was below 50 mm2 for the flat and curved design. During downhill walking and jogging, more than 140 mm2 were overloaded for each design., Conclusions: It was concluded that patients after total knee replacement should alternate activities such as power walking and cycling. For mountain hiking, patients are advised to avoid descents or at least use ski poles. Jogging or sports involving running should be discouraged after total knee replacement.

Seventy-six patients with septic arthritis (78 affected joints) were treated with a combination of arthroscopic irrigation, debridement, and antibiotic therapy according to the tested bacterial sensitivity. There were 62 knee, 10 shoulder, 5 ankle joints, and 1 hip joint. No antibiotics were added to the irrigating solution. The arthroscopic and radiological stage of infection, treatment, and outcome in these patients was analyzed. The patients were classified into three groups according to initial stage of joint infection (stage I: 21 patients, 22 joints; stage II: 43 patients, 44 joints; stage III: 12 patients, 12 joints). Causes of infection were: hematogenous dissemination in 54%, postoperative wound infection in 28% (17% after open, 11% after arthroscopic procedures). Other causes were: 10% intra-articular steroid injections, 3% diagnostic punctures, and 3% open traumatic injury of the joint. In 78% of the infected joints the causative organism could be identified: Staphylococcus aureus was the most common organism found (42%), followed by streptococci (15%), pneumococci (6%), Escherichia coli (4%), Staphylococcus epidermidis (3%), Borrelia burgdorferi (3%), and others in 5%. In the stage I group only one patient needed repeated arthroscopic irrigation, in the stage II group 52%, and in the stage III group 75%. Open revision for eradication of the infection was necessary in one joint with stage II and in two joints with stage III infection (3%). Two joints of the stage III group needed additional surgery after successful treatment of the infection. The combination of arthroscopic irrigation and systemic antibiotic therapy was able to cure 91% of the affected joints. Open revision was necessary in 4% of joints. The number of arthroscopic procedures and the efficacy of treatment depended on the initial stage of the infection. It is concluded that an arthroscopic staging of the initial joint infection has prognostic and therapeutic consequences.

Objective: To analyse and compare the shape of wear particles found in healthy and osteoarthritic human knee joints for monitoring the progress of osteoarthritis, the long-term prognosis and to evaluate therapeutic regimens., Method: Joint particles from seven patients with normal cartilage in all compartments of the knee joint, 12 patients with fibrillation of less than half the cartilage thickness (grade 1), seven patients with fibrillation of more than half the cartilage thickness (grade 2) and four patients with erosions down to bone (grade 3) were analysed. A total of 565 particles were extracted from synovial fluid samples by ferrography and analysed in a scanning electron microscope. A number of numerical descriptors, i.e. boundary fractal dimension, shape factor, convexity and elongation, were calculated for each particle image and correlated to the degree of osteoarthritis using non-parametric tests., Results: Experiments demonstrated that there were significant differences between the numerical descriptors calculated for wear particles from healthy and osteoarthritic knee joints (P < 0.01), suggesting that the particle shape can be used as an indicator of the joint condition. In particular, the fractal dimension of the particle boundary was shown to correlate directly with the degree of osteoarthritis., Conclusion: Numerical analysis of the shape of wear particles found in human knee joints may provide a reliable means for the assessment of cartilage repair after surgical or conservative treatment of osteoarthritis.

Thirty patients with 31 shoulders underwent clinical and radiologic evaluation 5 to 6 years after arthroscopic acromioplasty. The mean age was 51 years. The acromioclavicular (AC) joint was assessed for tenderness on palpation and pain on horizontal adduction of the shoulder. All patients underwent a radiologic examination consisting of an anteroposterior view of the AC joint and bilateral stress views. No patient had superior translation or widening of more than 1 mm of the AC joint on stress views on the unoperated side. On the operated side 12 (38%) shoulders showed signs of instability consisting of a superior translation of the clavicle of 2 to 3 mm, distraction on weight bearing view, or both. No severely osteoarthritic AC joint (grade 3 or 4) was unstable. The degree of osteoarthritis did not differ for both shoulders, suggesting that arthroscopic acromioplasty does not accelerate osteoarthritic change in the AC joint but can induce instability. Nine patients had tenderness over the AC joint and instability on stress views. They had a significantly reduced University of California Los Angeles score of 25 +/- 5 compared with the other patients (29.5 +/- 7). We conclude that preservation of the inferior capsule during arthroscopic acromioplasty is important for the integrity of the AC joint in patients without severe osteoarthritic changes.

Objectives: The new volatile anaesthetic desflurane is characterized by very low blood-gas and tissue-blood partition coefficients, so that rapid induction of anaesthesia and shorter recovery times can be expected. The aim of this investigation was to compare the effects of desflurane and isoflurane on haemodynamics and recovery time when used as part of a balanced anaesthesia technique for elective surgery., Methods: Fifty patients (18 years and older, ASA status I-III) scheduled for elective surgery (no laparoscopies) of at least 60 min duration were included in this open, randomised, phase-III clinical trial. After oral premedication with midazolam 7.5 mg 45 min before transfer to theatre, anaesthesia was induced with fentanyl 0.1 mg and thiopental 5 mg/kg; succinylcholine or vecuronium facilitated intubation. Desflurane and isoflurane, respectively, were used for maintenance of anaesthesia, both in 50% N2O, with the inspired concentration adapted to the degree of stimulation. All patients were ventilated in a semi-closed system; muscle relaxation was achieved with vecuronium. The electrocardiogram, heart rate (HR), and direct arterial blood pressure (BP) were recorded continuously and anaesthetic gas detection was performed by an infrared absorption technique. With termination of surgery the volatile anaesthetic was discontinued and the following emergence times recorded: spontaneous ventilation (VT > 300 ml), extubation, eye opening, correctly answering the date of birth, arrival in and possible discharge from the post-anaesthesia care unit (PACU)., Results: In all, 49 patients were studied at random (desflurane n = 24, isoflurane n = 25). Data of demographics and anaesthetic technique were comparable in both groups (Tables 2 and 3). Anaesthetic elimination (expressed as FA/FAO) was significantly more rapid in the desflurane group 3 min after termination of anaesthesia (Fig. 1). Comparing the emergence times, there was no significant difference between desflurane and isoflurane: in both groups patients opened their eyes 12 min (median time) after termination of the operation (Table 4). Haemodynamics (HR, systolic and diastolic BP) were comparable at intubation, skin incision, end of surgery, extubation, and in the PACU (Fig. 2a, b). In 2 patients a rapid increase in the inspired concentration of desflurane during induction of anaesthesia produced a profound sympathoadrenergic reaction with an excessive increase in BP and HR. Similar reactions in other patients did not occur when the inspired concentration of desflurance was slowly increased., Conclusions: Despite the physicochemical properties of the new agent, emergence times were similar for desflurane and isoflurane in our study. These results, which are in contrast to those of some other authors, are most probably due to the study design, which included the use of premedicants (midazolam) and a low dose of fentanyl. The reported sympatho-adrenergic reactions after rapid changes in the inspired concentration of desflurane during induction of anaesthesia have been observed by others as well. It seems that this initial cardiovascular stimulation can be avoided by slow increases in desflurane concentration. In summary, desflurane compares to isoflurane in balanced anaesthesia for general surgical procedures with regard to haemodynamics, while the time to awakening is not necessarely reduced.

The anterior cruciate ligament (ACL) is a crucial structure for a normal kinematic of the knee joint. Its rupture has been thought to present the initiation of a sequel leading to secondary damage of the meniscus and finally to osteoarthritis. Diagnosis of an ACL rupture is based on the history as well as on the physical examination. A positive Lachman-sign is diagnostic for an ACL lesion. The question whether an ACL rupture should be operated or not must be decided individually and is based on the demands of the patient. Conservative treatment includes rigorous physical therapy emphasizing strengthening exercises of the hamstrings and the gastrocnemius muscles as well as prorioceptive training. The indication for reconstruction is given, should instability persist. The timing of the operation is important for the outcome. This paper presents an overview of the literature including the rehabilitation program and a diagnostic concept used by the authors.

Kinematic and kinetic data were collected of 6 male and 6 female healthy subjects. For downhill walking a dismountable slope of 6 m length and a grade of 19.3% was built. Planar net joint moments and mechanical power at the knee joint were calculated for the sagittal view using force platform records based on standard inverse dynamics procedures. On the basis of a two dimensional knee model the patello femoral joint compressive forces were calculated. While the maximal extension moment for level walking was only 1.2 +/- 0.5 Nm/kg bw at a knee flexion angle of 20 degrees it was 2.6 +/- 0.6 Nm/kg bw at an angle of 40 degrees for downhill walking. This increased moment and knee flexion angle yields a 3 to 4 times bigger femoropatellar joint compressive force for downhill walking compared to level walking. Due to a smaller moment arm of female subjects the patello femoral joint compressive forces were bigger for females compared to males (14 N/kg bw for male subjects, 18 N/kg for female subjects during level walking and 50 N/kg bw for male subjects, 70 N/kg for female subjects during downhill walking). The femoropatellar joint compressive force for downhill walking is comparable to running, squatting or downstairs walking. Based on this investigation downhill walking must be considered a strenuous task for the femoro patellar joint and explains well why patients with anterior knee pain or osteoarthritis have problems during downhill walking.

Collecting data for administrative, statistical, medical, and organizational purposes is becoming increasingly important in anesthesia. In 1986 the Swiss Society for Anesthesiology decided to create a program that would be compatible for different computers and would expedite data collection. The system developed was called Information System for Operations (ISOP), which was written in the database and programming system Massachusetts General Hospital Utility Multi Programming System (MUMPS). It was installed in eight hospitals and met the initial requirements, but the individual requirements of the hospitals were greatly underestimated. MUMPS has an impressive data storage capability and handling when used in a personal computer (PC) network. The user-interface, however, is inferior to other PC packages, partly because windowing and mouse support were not implemented when the ANSI standard was set. Improved statistical programs, a module for on-line data acquisition, and intensive care unit (ICU) use will be additional modules to the program.

The report describes a computer system that provides statistical information on the anesthetic and surgical procedures performed by anesthetists and surgeons, reports on the operative activity of the anesthesia and surgical departments, and assists in daily scheduling of the program. Additional programs can be used for billing, displaying the use of (operating room OR) facilities by the various surgical divisions, and showing the actual stage of on-line operations with monitors. The software system MUMPS has been found to be a low-priced yet efficient and versatile multiuser system. The main features of the program are ease of use, prospective data entry (i.e. during the entire stay of the patient), and the possibility of modifying and expanding the system easily. Missing or inaccurate data are automatically brought to the attention of those who have performed the operation or the anesthesia by a program that is run periodically. The system has been found to be a useful tool for the daily scheduling of the OR program. It provides data for better scheduling of personnel and records can also be kept regarding the professional experience of physicians. The major deficiency of the program at this stage is its lack of a hierarchical structure. For example, it is unable to record multiple operations and/or anesthetic procedures for the same patient. This deficiency will be corrected in a newer version of the program.

We carried out continuous direct pH measurements of gastric fluid in 49 female patients pretreated with 300 mg ranitidine by mouth on the evening prior to surgery and 150 mg by mouth before the operation. A further 51 women were pretreated with 30 ml sodium citrate shortly before admission to the operating room. Twenty patients received 30 ml sodium citrate via a separate gastric tube after the first pH measurement; 22 were given no premedication. In 95% of cases, 30 ml sodium citrate was found to increase the pH to over 3.5 within 5 min; a failure rate of 5% can therefore be expected. This can be explained mainly by the failure of sodium citrate to mix thoroughly with the gastric fluid. Pretreatment with ranitidine increased the pH to over 4.0 in every case, and the pH on extubation was still over 4.0 even after delayed pH on extubation was still over 4.0 even after delayed or prolonged operations. We recommend that 30 ml sodium citrate be given shortly before the beginning of emergency obstetric operations. However, we prefer ranitidine for elective operations in patients at risk for aspiration because it increases of the gastric fluid pH to at least 4.0 in every case.

We investigated the influence of the patient's gender for diagnostic and therapeutic approach of physicians at the outpatient clinic of the university hospital of Basle. In a prospective study 13 male residents in their second and third year of medical training were observed in their management of 25 female and 25 male patients presenting with the leading complaint of abdominal pain with regard to taking of the medical history, the physical examination and the performed diagnostic and therapeutic procedures, without informing the participating physicians. The time spent for the first consultation and the number of follow ups performed were registered. Following differences in the management of female and male patients were observed: The time spent at the first consultation was 59 +/- 5 minutes in female and 45 +/- 3.5 in male patients (p less than 0.03). Fundoscopic examination was three times more often performed in female patients. Endoscopic examinations were more often observed in male patients (p less than 0.01). Antacids and H2-antagonists were more frequently prescribed in male (p less than 0.01). Spasmolytics and laxatives more frequently in female (p less than 0.01). In summary in male patients the diagnosis of functional disease was predominantly made after exclusion of an organic disease what does explain the use of more diagnostic procedures and the induction of a more specific therapy.