Antimicrobial Activity of the Most Common Antibiotic-Releasing Systems Employed in Current Orthopedic Surgery: in vitro Study.

PURPOSE OF THE STUDY Infections of joint replacements represent one of the most serious problems in contemporary orthopedics. The joint infections treatment is usually multimodal and involves various combinations of drug delivery and surgical procedures. The aim of this study was to evaluate and compare the bacteriostatic and bactericidal properties of the most common antibiotic carriers used in orthopedic surgery: bone cements mixed with antibiotic and porous calcium sulfate mixed with antibiotic. MATERIAL AND METHODS Three commercial bone cements (Palacos®, Palacos® R+G, Vancogenx®) and commercial porous sulfate (Stimulan®) were prepared with a known concentration of vancomycin (a glycopeptide antibiotic). Specifically, for the purpose of our study, the testing specimens were prepared to release 0, 1, 2, 4, 8, 16, 32, 64, 128, 256, and 512 mg of vancomycin into 1 liter of solution. The specimens with increasing amount of antibiotic were placed in a separate tubes containing 5 mL of Mueller-Hinton broth inoculated with a suspension (0.1 m, McFarland 1) of the reference strain CCM 4223 Staphylococcus aureus to evaluate their bacteriostatic properties (broth dilution method). After this initial incubation and evaluation of the broth dilution method, an inoculum from each tube was transferred onto blood agar plates. After another 24-hour incubation under the same conditions, we evaluated the bactericidal properties (agar plate method). As many as 132 of independent experiments were performed (4 specimens × 11 concentrations × 3 repetitions = 132). RESULTS The bacteriostatic properties of all investigated samples were excellent, perhaps with the exception of the first bone cement (Palacos®). The sample Palacos® started to exhibit bacteriostatic properties at concentrations ≥ 8 mg/mL, while all other samples (Palacos R+G®, Vancogenx®, and Stimulan®) were bacteriostatic in the whole concentration range starting from 1 mg/mL. The bacteriocidic properties did not show such clear trends, but correlated quite well with different properties of the investigated samples during mixing - the most homogeneous samples seemed to exhibit the best and the most reproducible results. DISCUSSION The reliable and reproducible comparison of ATB carriers is a difficult task. The situation is complicated by high numbers of local antibiotic carriers on the market, numerous antibiotics used, and differences in clinical trials at different laboratories. Simple in vitro testing of bacteriostatic and bacteriocidic properties represents a simple and efficient approach to the problem. CONCLUSIONS The study confirmed that the two most common commercial systems used in the orthopedic surgery (bone cements and porous calcium sulfate) prevent bacterial growth (bacteriostatic effect), but they may not be 100% efficient in complete elimination of bacteria (bacteriocidic effect). The scattered results in the case of bacteriocidic tests seemed to be connected with the homogeneity of ATB dispersion in the systems and with the lower reproducibility of the employed agar plate method. Key words: local release of antibiotics; bone cements; calcium sulfate; antimicrobial susceptibility.

[Repeated Sterilization of Articular Components of Joint Replacements with Ethylene Oxide Does Not Affect the Structure and Properties of UHMWPE]. / Opakovaná sterilizace artikulacních komponent kloubních náhrad etylenoxidem nemá vliv na strukturu a vlastnosti UHMWPE.

PURPOSE OF THE STUDY In clinical practice UHMWPE is the most commonly used material for manufacturing articular components of joint replacements. The purpose of this study is to find out whether repeated ethylene oxide sterilization results in oxidative degradation of UHMWPE or not and also whether the oxidative degradation of various types of ethylene oxide-sterilized UHMWPE depends on storage time or not. MATERIAL AND METHODS The set included 12 samples of UHMWPE (three samples with different modifications (virgin PE, with E vitamin and cross-linked with thermal treatment) and different number of sterilizations (0×-3×)). The set also included 8 samples of commercial components of hip or knee replacements sterilized with ethylene oxide and stored for different storage periods. The oxidative degradation was assessed by infrared microspectroscopy, based on which the oxidation index (OI), transvinylene index (VI), crystallinity index (CI) and E vitamin index (EI) were calculated. Mechanical properties of UHMWPE were obtained through microhardness measurements. Statistical processing of the results was performed. RESULTS In all the samples, very low oxidative degradation values were reported (most OI values < 0.1). All radiation crosslinked UHMWPE samples showed an increased VI index and a slightly lower crystallinity index. All unmodified samples (irrespective of whether or not and how many times or how long ago the samples were sterilized with EtO) had almost zero value of VI. Changes in crystallinity were negligible (in the rage of 0.56-0.63), which required very accurate measurements of micromechanical properties. Yet, linear correlation was established between microhardness and crystallinity. DISCUSSION All the mentioned indices changed as anticipated: OIs were very low and slightly increased with time of storage, VIs of radiation crosslinked samples grew in proportion to the total gama radiation dose, CIs decreased in samples thermally treated by remelting, and EIs were very low due to negligible concentration of stabiliser (0.1%) in the samples of medical grade UHMWPE. CONCLUSIONS All samples showed zero or minimum oxidative degradation. This confirmed that neither ethylene oxide sterilization, nor multiple EtO sterilization or longer storage of polymer after ethylene oxide sterilization result in major oxidative degradation. Key words: UHMWPE, ethylene oxide, sterilization, oxidation, infrared spectroscopy, microhardness.

Stemless Hemiarthroplasty of the Shoulder Using the SMR® System: Summary of Six-Year Experience and Surgical Technique.

PURPOSE OF THE STUDY In the last number of years, the anatomic hemiarthoplasty has gradually been pushed out of clinical practice by modern reverse shoulder arthroplasty (RSA) designs. This is due to the clear excellent functional results of RSAs in a wide spectrum of indication criteria. Nevertheless, RSAs have several possible complications that cannot occur in an anatomic hemiarthroplasty. In anatomic hemiarthoplasty, the importance of correct indication criteria and observing correct operative technique including soft tissue reconstruction is much more important than in RSA. Furthermore, there is a clear recent trend of increased use of humeral components fixed only in the proximal metaphyseal cancellous bone. Our aim was to summarise our six-year experience with the SMR® Stemless (LimaCorporate, Italy) system which is one of the most modern ones. MATERIAL AND METHODS Twenty cases of SMR® Stemless anatomic shoulder hemiarthroplasty performed between 2016 and 2021 were included in the study. All patients were followed up prospectively. The function was evaluated preoperatively and at the last follow-up. We evaluated the range of active elevation, classic Constant Score (CS) and pain level according to the visual analogue scale (VAS). Statistical evaluation was performed by using basic statistical methods and the statistical significance of the results was assessed with a paired t-test. Level of statistical significance was set at p= 0.01. RESULTS The mean follow-up in our cohort was 3.01 years (range 0.32-5.69, Median 2.82, SD 1.56) All cases were indicated for surgery due to primary osteoarthritis with a limitation of movement and pain. The mean postoperative CS was 85.7 (range 70-96, Median 86, SD 6.83). The mean active elevation postoperatively was 143° (range 100-170°, Median 150°, SD 20.76). Mean postoperative pain according to VAS was 1.05 (range 0-4, Median 1, SD 1.02). The mean preoperative elevation was 60.5° (range 30-100°, Median 65°, SD 18.83). After surgery the mean elevation increased to 143° (range 100-170°, Median 150°, SD 20.76). Statistical evaluation showed a statistically significant increase in the CS (41.7 preoperatively to 85.7 postoperatively), range of active elevation (60.5° preoperatively to 143° postoperatively) and a statistically significant decrease in pain (VAS 6.95 preoperatively to 1.05 postoperatively). We observed no cases of failure or loosening of the implant. A statistically significant increase in post-operative range of motion was demonstrated. DISCUSSION Most modern shoulder arthroplasty designs now include implants allowing for proximal humerus metaphyseal fixation in hemiarthroplasty and even RSA designs. The advantage of metaphyseal fixation without the use of a longer stem is clear. Notably, treatment of periprosthetic humeral fractures is simpler, extraction of the implant for any reason is easier and the preoperative anatomic position of the humeral head can be respected. As with any anatomic shoulder arthroplasty, the functional result is dependent on correct indication criteria, precise surgical technique, correct humeral head position and soft tissue reconstruction - primarily the rotator cuff. CONCLUSIONS Between 2016 and 2021, we performed 20 SMR® stemless shoulder hemiarthroplasties for primary osteoarthritis. The mean follow up was 3 years. The shoulder function improved significantly post-operatively in all patients. There were no cases of implant loosening or failure. Radiographic evaluation showed no implant loosening or change in implant position in the humeral metaphysis. Key words: shoulder joint replacement, reverse shoulder arthroplasty, SMR, stemless, total shoulder arthroplasty, shoulder hemiarthroplasty, EPOCA, wear.

Does the Femoral CCD Angle Measurement in a Standard AP Projection Correlate with the True Anatomical Shape of the Femur?

PURPOSE OF THE STUDY This study aims to ascertain whether a high anteversion of the femoral neck can influence the measurement of the caputcollum-diaphyseal (CCD) angle on a plain anteroposterior (AP) radiograph of the proximal femur. MATERIAL AND METHODS We developed a new method of measuring the CCD angle and femoral neck version of the femur. This was done with the use of a computer program that utilised the measurement of the entire visualised area of femoral neck and shaft to calculate their long axis. Using this method, we measured the CCD angle and femoral neck version (FNV) of 100 photographed cadaveric femurs in two projections: The condylar line (CL) projection and the femoral neck (FN) projection. The same method was applied to 50 radiographs of the same femurs. The femurs were divided into three groups depending on the femoral neck version: Retro (FNV of <0°), Normal (FNV of 0-15°) and Ante (FNV of >15°) RESULTS We found a statistically significant difference in the CCD angle measured in the FN and CL projections in the Normal and Ante groups but not in the Retro group. There is a significant correlation between the increase in FNV and the difference between the measured CCD values in the FL and CL projections. The femoral neck version of our cadaveric femurs varied from -14. 4° to 31. 5° which is a range of more than 35°. CONCLUSIONS From the results, it is clear that with an increase in femoral neck anteversion, there is a statistically significant difference in the CCD angle measured between the two projections. This difference can be up to almost 10°. Surgeons should be aware of the limitation of the AP projection when planning for surgery on the hip. Key words: femoral neck anteversion, CCD angle, templating, preoperative planning.

Reverse Total Shoulder Arthroplasty: 14-Year Clinical Experience with 496 Performed Arthroplasties.

PURPOSE OF THE STUDY Reverse total shoulder arthroplasty (RSA) can be considered a proven method for the treatment of the most severe shoulder joint affections. In this study, we present 14-year experiences of the authors with the LimaCorporate SMR® RSA system in 496 cases. MATERIAL AND METHODS Included in the study are 496 RSAs performed between 2007 and 2020. We successfully followed up 368 shoulders in 358 patients. This was a prospective study with function being evaluated preoperatively and at the last follow-up in 2020. We evaluated the range of motion in active elevation and the classic Constant Score (CS). According to this score, the pain level was also evaluated. Standard statistical methods were used with a paired t-test used for comparisons of values. RESULTS The mean follow-up in our group was 5.5 years (0.7-13.6, SD 3.22, median 4.96). Indications were: primary osteoarthritis (84), acute trauma (69), posttraumatic sequelae (79), cuff tear arthropathy (37), RA (29), chronic dislocations (18), final treatment of infectious complications (7), avascular necrosis (6), tumours (4) and TSA revisions (9). The mean post-operative CS of all patients was 71.9 (2-94, SD 11.26, median 73). The mean post-operative active elevation was 127.35° (30°-180°, SD 28.36, median 130°). The mean pain level at final follow-up was 0.65 (0-3, SD 0.65, median 1). There was a statistically significant improvement In the CS (26.9 to 71) and the final achieved elevation (48.5° to 127.35°) in all groups except acute traumas for obvious reasons. A significant decrease in pain (2.8 to 0.65) was observed in all groups. We saw no implant failures or UHMWPE component wear. DISCUSSION We compared our results with those published by other authors. When considering the functional outcomes, our results are comparable with those published previously. Compared to other studies, an interesting result is the low incidence of scapular notching. In our cohort of patients, it was only present in 10 (2.7%) cases. We attribute this to the design of the SMR® implant which meets the main criterium of a modern shoulder arthroplasty system: modularity of both glenoid components. The glenospheres are available in 36, 40 and 44mm sizes with standard and distalised options. Furthermore, the system also contains the Axioma® revision glenoid component. Humeral stems are available in a range of sizes and lengths including revision stems. The humeral body is also available in two sizes. The short variant is optimal for revision with hemiarthroplasty to reverse conversion. CONCLUSIONS During a period of 14 years, we performed 496 implantations of RSAs using the SMR® system. We evaluated 368 cases with an average follow-up of 5.5 years. During long-term follow-up we experienced no implant failures or complications indicative of any constructional insufficiencies. We saw no signs of UHMWPE liner wear. The SMR® system allows for treatment of even the most complex shoulder affections due to its high modularity. Key words: shoulder joint replacement, reverse shoulder arthroplasty, SMR®, Axioma®, outcomes, ROM, scapular notching, complication, polyethylene wear, UHMWPE.

[Comparison of the Quality of the Most Frequently Used New UHMWPE Articulation Inserts of the Total Hip Replacement]. / Porovnání kvality nejcasteji pouzívaných nových UHMWPE artikulacních vlozek náhrady kycelního kloubu.

PURPOSE OF THE STUDY For an orthopedic surgeon it is difficult or even impossible to estimate the real quality of ultrahigh molecular weight polyethylene (UHMWPE) liners that are used in the total joint replacements (TJR) just on the basis of information given by the manufacturers. At the same time, the quality of the UHMWPE liner can impact strongly on the total lifespan of the implanted TJR. This work aims at independent, objective comparison of properties of the UHMWPE liners for total hip replacements (THR), which are most frequently used in the Czech Republic. MATERIAL AND METHODS We analyzed seventeen most frequently implanted UHMWPE cups of different manufacturers implanted in the Czech Republic between 2014 and 2015 and four control samples prepared by standard industrial-scale procedures according to our instructions, whose modification (crosslinking, thermal treatment, stabilization and sterilization) was known in detail. The UHMWPE polymer was characterized by four independent microscale methods, suitable for relatively small and irregular specimens such as THR cups: infrared microspectroscopy (IR), differential scanning calorimetry (DSC), and thermogravimetric analysis (TGA). RESULTS The employed methods yielded quite complete information about the investigated UHMWPE materials. IR spectra enabled us to calculate oxidation indexes (OI, measure of oxidative damage), trans-vinylene indexes (VI, measure of absorbed radiation dose during crosslinking and/or sterilization) and crystallinity indexes (CI, amount of crystalline phase that strongly influences mechanical performance). DSC curves were employed in calculation of crystallinities (wc, proportional to CI) and melting points (Tm, proportional to the average thickness of crystalline lamellae). MH measurements confirmed that the observed structure changes showed a real impact on mechanical properties. TGA experiments gave rough estimate of stabilization and, consequently, possible long-term oxidation resistance. Significant correlations among oxidative damage (OI), crystallinity (CI, wc) and microhardness (Hv) were statistically proven. The highest oxidative degradation was usually observed in samples thermally treated by annealing and/or sterilized by gamma irradiation. DISCUSSION The results confirmed our expectations that the UHMWPE liners from various manufacturers can be significantly different as far as their molecular structure, supermolecular structure, and mechanical properties are concerned. The differences among the various UHMWPE can be expected to increase after the implantation during in vivo. CONCLUSIONS From the clinical practice point of view, the results showed the following facts: (i) In the field of THR, all manufactures prefer crosslinked types of UHMWPE due to their increased wear resistance; non-crosslinked UHMWPEs are regarded as obsolete. (ii) Most of the manufacturers prefer ethylene oxide or gas plasma sterilization to gamma sterilization because the gammasterilized UHMWPEs exhibit lower long-term oxidation resistance. (iii) Modern trend is the stabilization of UHMWPEs with vitamin E. Key words: UHMWPE, hip replacements, oxidative degradation, infrared spectroscopy, microhardness.

[Comparison of Explanted UHMWPE Hip Replacement Components of Various Manufacturers after 10 Years in vivo]. / Porovnání explantovaných UHMWPE komponent náhrady kycelního kloubu ruzných výrobcu po 10 letech in vivo.

PURPOSE OF THE STUDY Considered to be one of the most common causes of aseptic loosening of endoprostheses is the THA failure due to the wear of articulating components, UHMWPE in particular. The purpose of this study is to verify, in terms of oxidative damage and other parameters, the differences between the UHMWPE implants made by various manufacturers explanted for aseptic loosening with the same life span in vivo. MATERIAL AND METHODS In the period 2010-2015, a total of 21 THA articulating components (cups) made of Ultrahigh molecular weight polyethylene by seven different manufacturers were explanted. For each manufacturer, three UHMWPE cups with the same life span (10-12 years after the primary implantation) were evaluated. The damage to the examined joint replacements was described in complexity using three different criteria, namely independently by three evaluators - experienced orthopaedic surgeons. The evaluated criteria were the following: degree of osteolysis determined based on the preoperative radiographs, wear rate of the explanted UHMWPE component, and extent of perioperatively detected granuloma. Oxidative damage and other structural characteristics of explanted cups were studied by means of infrared spectroscopy and microhardness testing. The correlation between the clinical orthopaedic assessment and oxidative damage were statistically processed. RESULTS Strong correlations between the oxidative damage and crystallinity, strong correlations between all types of orthopaedic assessments, negligible correlations between trans-vinylene index and all the other quantities, and moderate correlations between the oxidative damage and clinical evaluation were identified. It was confirmed by experimental measurement that the observed high oxidative damage, resulting in increased crystallinity, manifested itself also in micromechanical properties of the material at the respective site of the THA articulating component. DISCUSSION The discussion includes the comparison of correlations of individual quantities as well as potential effects on the differences in values of components made by individual manufacturers. The values are related to the data in literature and generally accepted claims. CONCLUSIONS At the time of failure almost all the components showed severe or even critical oxidative damage that strongly correlated with the overall clinical evaluation of the damage to the implant. This confirmed that the oxidative degradation is one of the main causes of THA failure. Key words: UHMWPE, oxidation index, crystallinity, THA failure, wear.

[The Risk of Total Joint Replacement Infectious Complications in Relation to the UHMWPE Particle Adhesion Area]. / Riziko infekcních komplikací po náhrade nosného kloubu ve vztahu k adhezní plose UHMWPE cástic.

PURPOSE OF THE STUDY Periprosthetic joint infection is a major complication which in most of the cases requires a long-term administration of antibiotics and often necessitates undergoing multiple challenging surgeries. Bacterial adhesion to foreign material is one of the key risk factors associated with periprosthetic joint infection. The foreign material with large adhesion area might be also the UHMWPE (Ultrahigh molecular weight polyethylene) particles released during the wear process from the surface of articulating components. The purpose of this study is to evaluate potential adhesion areas of wear particles in relation to diverse distribution of the size and shapes of wear particles in periprosthetic tissue and to assess an increase in the risk of infectious complications associated with an increase in the adhesion area of wear particles. MATERIAL AND METHODS The size and morphology of model and real UHMWPE particles were determined with the use of light microscopy and scanning electron microscopy. By determining the morphological descriptors, the surfaces of individual particles for different distributions of polyethylene particles were calculated. When measuring the model wear particles, 6 model situations were simulated, in which comparisons with the control measurement by the BET (Brunauer-Emmet-Teller) method were made. RESULTS The variability of individual morphological descriptors demonstrates the effect on the total surface of particles. The calculated coefficient defines how many times the particle surface increases when corrected to the given descriptor (elongation, flattening, roughness, porosity). The total area of real wear particles at 1 year is 4,622 cm2, at 20 years it is 92,440 cm2. Based on our calculations, the area of particles where a biofilm is actually formed (approximately 50 bacteria may adhere to a particle of 3µm in diameter) is 809.5 cm2 at 1 year and 16,190 cm2 at 20 years. DISCUSSION According to the measurements, the size of the potential adhesion area of metal parts and polyethylene particles becomes equal already after several weeks of endoprosthesis usage and after a few years it is many times larger. The question is whether the risk of bacterial adhesion, i.e. also the risk of infectious complications of TEP actually increases. The clinical practice suggests that the number of infections e.g. 10, 15 or 20 years after the primary implantation is not statistically higher, despite the confirmed growth of potential adhesion area in the form of UHMWPE particles. This fact could be explained by a partially equal regulatory pathway of infection and polyethylene disease. The immune system stimulated by wear particles might better resist the hematogenic infection. CONCLUSIONS The study outcomes clearly indicate that the area of polyethylene wear particles considerably increases over time. In spite of the fact that only approximately 10% of wear particles show parameters (also with respect to the size of particles and bacteria) for potential bacterial adhesion, this area is many times larger than the area of metal parts of the endoprosthesis. Key words: UHMWPE particle, adhesion, biofilm, wear, TJR infection.

[Longterm Results of Non-Anatomical Reconstruction of Proximal Humerus]. / Dlouhodobé výsledky neanatomické rekonstrukce proximálního humeru.

PURPOSE OF THE STUDY Treatment of comminuted three- and four-part displaced proximal humerus fractures continues to be discussed in daily trauma practice. In fractures with metaphyseal comminuted fractures the anatomical reconstruction is often technically unfeasible. For cases of comminuted metaphyseal proximal humerus fractures we proposed the so called non-anatomical reconstruction with simple osteosynthesis. Even today, when nailing and plating are commonly used in osteosynthesis, the non-anatomical reconstruction plays an irreplaceable role. Its application is conditioned by at least partially preserved vascular blood supply of the head fragment. This paper describes our original technique to manage these fractures and provides an evaluation of results of the group of patients in whom this procedure was performed. MATERIAL AND METHODS Our group included a total of 72 patients (who underwent surgery in the period from 1 January 1989 to 22 March 2016), of whom 57 were clinically assessed (8 patients died, 7 patients failed to be traced back). The mean age at the time of procedure was 53.61 years (range 19-81 years). The mean follow-up was 14.3 years (range 0.3-26.3 years) after the surgery. The method consists in removing the comminution zone, impacted modified diaphyseal fragment to head spongiosis and osteosynthesis of greater and lesser tubercle or their remainders to diaphyseal fragment using tensile cerclage. RESULTS The mean post-operative Constant score was 81.4 (range 30-100 points). The mean abduction was 120.4 degrees (range 60-165 degrees) and ventral flexion was 129.2 degrees (range 70-170 degrees). Excellent clinical outcome according to the Constant score was achieved in 19 patients, good outcome in 23 patients, fair in 8 patients and poor in 7 patients. DISCUSSION We have been using our original method for 27 years. Compared to osteosynthesis by locking plates, minimally invasive procedures and trauma shoulder joint replacement, our method helps achieve very good clinical outcomes. Its main advantage, however, is the fact that by this technique the specific type of fractures can be treated, otherwise manageable exclusively by arthroplasty. CONCLUSIONS At our clinic, the non-anatomical reconstruction belongs to irreplaceable methods for treating certain proximal humerus fractures. The clinical outcomes of this method can be described as very good. The method of non-anatomical reconstruction eliminates the disadvantages and risks of arthroplasty. Nonetheless, it shall be stressed that this method can be successful exclusively when applied to precisely indicated types of fractures and when performed with technical precision. Its another advantage are the minimal financial requirements. Key words: non-anatomical reconstruction, osteosynthesis, proximal humerus, cerclage.

[Long-Term Results of the Ludloff Procedure in Relation to the Intraoperative Finding on Acetabular Labrum]. / Dlouhodobé výsledky operace dle Ludloffa ve vztahu k operacnímu nálezu na labrum acetabulare.

PURPOSE OF THE STUDY Developmental dysplasia of the hip still remains one of the most discussed topics in paediatric orthopaedics. The comprehensive care of paediatric patients with congenital developmental dysplasia of the hip at our department in the period from 1970 to 1985 included, among other things, the open reduction using Ludloff s approach in hip joints where closed reduction was not possible. This technique was supported by some of our own previous observations, such as the original classification of intraoperative findings on acetabular labrum (limbus). This study aims to evaluate the long-term results of treatment of our patients where Ludloff s open reduction was used and seeks to establish a conclusive correlation between the final result and the method of treatment of individual types of limbus, possibly confirming or ruling out that the dependence of later development of the acetabulum is dependent on correct and sparing treatment of this barrier to reduction. MATERIAL AND METHODS In the period from 1970 to 1985, the Ludloff s open reduction was performed in 70 patients. In 8 cases bilateral surgery was carried out. A total of 78 hip joints were operated on. The patients underwent the surgery at the age of 5-23 months. Postoperatively, the Hanausek biomechanical apparatus was applied to complete the treatment. In total, documentation of 21 surgeries performed in 20 patients was successfully tracked down. Two patients were removed from the group for incomplete documentation. The final group of patients included a total of 18 patients, of whom there were 13 women and 5 men. In one female patient the surgery was performed bilaterally. The shape of the femoral head, the center-edge (CE) angle and the degree of osteoarthritic changes were assessed on the pelvic radiograph of each patient. The functional result was evaluated using the Harris Hip Score (HHS). RESULTS For the purpose of assessment, the patients were divided into sub-groups based on the intraoperative finding on acetabular labrum. Type I limbus was found in a total of 5 cases. The mean HHS was 93, the mean CE angle was 22.5°. Aseptic necrosis occurred in one patient. Type II limbus was found in a total of 3 patients. The mean HHS was 84, the mean CE angle was 22°. Aseptic necrosis was observed in one patient. Type III limbus was found in 8 patients. The mean HHS was 79, the mean CE angle was 19.4°. Osteoarthritic changes of degree II-III were identified. Necrosis of the femoral head was recorded in 2 patients. Type IV limbus was found three times. The mean HHS was 73, the mean CE angle was 13.3°. Osteoarthritic changes of type III were present. Necrosis of the femoral head was recorded altogether in 2 patients. DISCUSSION The results of the Ludloff procedure reported in the available literature differ markedly as to the resulting function of the hip joint and the incidence of avascular necrosis. No author gave a description of the actual acetabular labrum deformity or showed a detailed description of individual vessel ligations. The advantage of this method is beyond any doubt its low invasiveness and when correctly performed also the minimal burden to the child. Its disadvantage is a certain degree of difficulty in performing this surgery, a worse visualisation of all barriers to reduction and a more challenging treatment of the posterior portion of the hip joint compared to techniques using the anterior approach. CONCLUSIONS Our outcomes indicate that the resulting Harris Hip Score was best in patients with the intraoperative finding of type I limbus. All the other types (II-IV) showed worse HHS results. From the current perspective, it is in all likelihood more advantageous to use surgical approaches that enable better visualisation of the anatomical deformities and allow for better options for their treatment. Key words: congenital hip dislocation, surgical treatment, open reduction, Ludloff procedure, acetabular labrum.

[Analysis of Oxidative Damage to Components Removed from Beznoska/Poldi Total Hip Replacements]. / Analýza oxidacního poskození explantovaných komponent náhrady kycelního kloubu Beznoska/Poldi.

UNLABELLED: PURPOSE OF THE STUDY Ultrahigh molecular weight polyethylene (UHMWPE) is today the most frequently used bearing surface in total joint replacements (TJR) because of its properties, i.e., excellent biocompatibility, good mechanical and tribological performance and high wear resistance. UHMWPE liners are the most loaded TJR components and, therefore, their properties are decisive for TJR longevity. This study had three objectives: 1) to evaluate the oxidative degradation of explanted UHMWPE components; 2) to look for a statistically significant relationship between the extent of oxidative degradation and the durability of joint replacements; and 3) to investigate whether the durability of a TJR was related to the type of sterilisation used in manufacture. MATERIAL AND METHODS The study included 26 acetabular components obtained at revision arthroplasty between 2004 and 2013 from patients in whom a Beznoska/Poldi total hip replacement was used in the period from 1977 to 2002. The average age of the patients at the time of primary implantation was 57.9 years, the average longevity of the components removed was 18.63 years (range, 6.9 to 27.9 years). Samples of worn out and unworn areas from explanted components were processed in a three-step procedure in order to finally obtain 2-mm microtome sections. These were studied by infrared microspectroscopy. Oxidative damage to UHMWPE was determined as the oxidation index (OI); radiation damage to UHMWPE during sterilization was evaluated as the transvinylene index (VI); oxidation-induced changes in the polymer structure and its properties were characterised as the crystallinity index (CI); and local changes in mechanical properties due to oxidative degradation were assessed as microhardness (MH). Spearman's correlation coefficient and the Wilcoxon two-sample test were used for statistical analysis. RESULTS The OI values (average and maximum) in both worn out and unworn surface areas were related to component longevity. The difference between the oxidation index of ruptured components and that of the other components was statistically significant. Significant differences were also found between the average and maximum OI values of worn out areas and those of unworn surfaces. The relationship between the average oxidation index in both the unworn and worn out areas of UHMWPE components and the longevity of cracked components was statistically significant. DISCUSSION Our results show that the OI values obtained by microspectroscopy correlated with both the microscopic damage and the longevity of UHMWPE liners and the correlation was statistically significant also in relation to the longevity of total replacements. Relationships amongst OI, VI, CI and MH values as well as their relation to failure and longevity of total replacements are discussed. CONCLUSIONS It can be concluded that infrared microspectroscopic measurement of OI values is a simple and fast method to characterise UHMWPE liners. In addition, the IR spectra also show other supplementary characteristics, such as VI and CI indices. These values provide information on the quality of various UHMWPE types currently used in TJR surgery. The types of UHMWPE which exhibit high oxidative degradation should be avoided in clinical practice due to increased risk of early TJR failure. Responsible orthopedic surgeons should be aware of this fact and, if possible, collaborate with an independent, noncommercial laboratory in order to evaluate the quality of various UHMWPE liners used in their hospitals. KEY WORDS: UHMWPE, oxidation, total joint replacement, infrared spectroscopy, microhardness.

PCR diagnostic system in the treatment of prosthetic joint infections.

In our prospective study, we examined whether a multiplex PCR diagnostic method is suitable for the primary detection of pathogens. We also examined the possibility and sensitivity of detecting genes responsible for biofilm production and methicillin resistance. From 2007 to 2009, 94 patients were included in the study. A UNB (universal detection of 16S ribosomal bacterial DNA) and UNF (universal detection of pathogenic fungi) were used in the primary detection. A multiplex assay for biofilm production, methicillin resistance allowed us to distinguish between Gram positivity and negativity and to detect Staphylococci. From all the samples, the culture was positive in 53.2 % of cases, and by using the UNB method, we detected bacteria in 79.8 % of cases-the UNF detection of fungi was positive in 10.6 % of cases. In 75 % of positive findings, we detected a Gram-negative bacterium in 65.3 % of cases. In 47.2 % of Staphylococci detected, the ability to produce biofilm was confirmed. 61.1 % of the Staphylococci exhibited a methicillin resistance. Our multiplex scheme cannot yet fully replace microbial cultivation but can be a rational guide when choosing an appropriate antibiotic therapy in cases where the microbial culture is negative.

[Effect of sterilisation with formaldehyde, gamma irradiation and ethylene oxide on the properties of polyethylene joint replacement components]. / Vliv sterilizace formaldehydem, gama zárením a etylenoxidem na vlastnosti polyetylenových komponent kloubních náhrad.

PURPOSE OF THE STUDY: Each method of sterilisation has some effect on the structure and properties of UHMWPE and thus also on joint replacement longevity. This study was designed to compare, using objective methods of measurement, several kinds of sterilisation and to recommend the one which has the best prospect for making joint replacements last longer. MATERIAL AND METHODS: Two groups of UHMWPE samples were tested. Group 1 included virgin GUR 1020 polyethylene, non-modified and non-sterilised (Meditech, Germany). Group 2 comprised of three sets of samples sterilised with formaldehyde, gamma irradiation and ethylene oxide, respectively. In both groups, physicochemical properties were assessed by infrared spectroscopy (IR), and the oxidation (OI) and trans-vinyl (VI) indices, which show the degree of oxidation of a material, were determined. Free-radical concentrations were measured by the method of electron spin resonance (ESR). The mechanical properties of each sample were studied using small punch tests (SPT) and testing microhardness (MH). Any change in mechanical properties can affect, to various degrees, the quality and longevity of a prosthetic joint. RESULTS: The samples sterilised by gamma irradiation showed higher values of both the OI (0.37) and the VI index (0.038) than the other samples (OI, 0.02 to 0.05 and VI, 0). Also, the free-radical concentration was detectable only in the gamma-sterilised sample. Values obtained for mechanical properties were as follows: peak load in the range of 58.48 N (gamma irradiation) to 59.60 N (ethylene oxide); ultimate load in the range of 46.69 N (gamma irradiation) to 57.50 N (ethylene oxide); ultimate displacement in the range of 4.29 mm (gamma irradiation) to 4.58 mm (virgin polyethylene and formaldehyde); and work to failure in the range of 185.18 mJ (gamma irradiation) to 205.89 mJ (virgin polyethylene). Microhardness values were obtained in the following ranges: 41.2 to 44.6 MPa (virgin polyethylene); 40.2 to 44.1 MPa (formaldehyde); 46.1 to 49.3 MPa (gamma irradiation); and 40.3 to 44.2 MPa (ethylene oxide). DISCUSSION: The samples sterilised with formaldehyde and ethylene oxide have mechanical properties very similar to virgin polyethylene, they are not damaged by oxidation and do not contain free radicals. Owing to these characteristics, the immediate and long-term oxidation stability of the three samples is higher. The sample sterilised by gamma irradiation showed the presence of free radicals and immediate and long-term oxidative degradation. This results in the deterioration of mechanical properties and the growth of crystallinity due to enhanced oxidation and leads to higher polyethylene microhardness. CONCLUSIONS: Sterilisation with gamma irradiation results in oxidative degradation and mechanical property deterioration, which is one of the potential risks of a shorter life span of joint replacements. The use of ethylene oxide or formaldehyde does not change polymer properties nor has any effect on oxidation of materials. Therefore, a longer life expectancy of the joint replacements sterilised with ethylene oxide can be expected. The life span of their joint replacements is a key issue for the patients. Prosthetic joint loosening is painful and the patient often requires re-implantation. A higher number of re-implantations is associated with higher costs for the institution involved and, consequently, for the whole health care system. Although this study basically deals with chemical issues, it informs the surgeon of the latest developments leading to the improvement of implanted materials, which can increase the life expectancy of joint replacements and patients' satisfaction.

Fibroepithelioma of Pinkus.

Basal cell carcinoma (BCC) is recently the most common cancer in humans characterized by several histopathological subtypes. Fibroepithelioma of Pinkus (FEP) is traditionally classified as a very rare variant of BCC, however, it manifests clinical and morphological differences that distinguish it from most other types BCCs. This study was performed to evaluate the incidence of FEP and clinical-pathological characteristics of patients diagnosed with this tumor. Four cases of primary FEP (3 females, 1 male, mean age 53.4 y) were analyzed retrospectively. The prevalence of FEP was 0.7 % of all diagnosed BCCs. Topographically, tumors were localized on the right brachium, right gluteal region, left mesogastrium, and right side of the abdomen. Histological examination showed typical anastomosing cords of basaloid cells extending from the overlying epidermis into the loose fibrous stroma in the dermis. Mitotic activity or significant cellular atypia, as well as sign of solar dermatosis were absent. Mean horizontal and vertical diameter of the lesions were 7.7 and 2.8 mm, retrospectively. We did not observe infiltration of deeper skin structures. All lesions were removed completely and classified as pathological stage pT1. Three cases manifested typical picture of a "pure" FEP, one lesion had partially a feature of nodular type BCC, too. Although FEP is conventionally considered as indolent BCC variant with a favorable clinical outcome, recent evidences also favors its classification as a form of trichoblastoma. This is appropriate example how some types of cutaneous tumors can overlap in terms of dignity and clinical-morphological characteristics. This should be taken into account in differential diagnosis and in predicting of biological behaviour of the individual tumors of the skin (Tab. 2, Fig. 3, Ref. 26).

[Current knowledge on the effect of technology and sterilization on the structure, properties and longevity of UHMWPE in total joint replacement]. / Soucasné poznatky o vlivu technologie výroby a sterilizace na strukturu, vlastnosti a zivotnost UHMWPE v kloubních náhradách

Ultrahigh molecular weight polyethylene (UHMWPE) is the most frequently used bearing surface in currently used total joint replacements (TJR). According to the literature available, UHMWPE is the best polymer material, in terms of biocompatibility, mechanical properties and wear resistance, for this application. In spite of this fact, UHMWPE wear (i.e., release of microscopic particles from the polymer surface) remains one of the main reasons of TJR failures. Consequently, the wear of UHMWPE is a subject of intensive study by both materials scientists and orthopaedic surgeons. The structure and properties of UHMWPE strongly depend on the way of processing and post-processing modifications. The processing includes polymer resin preparation (microparticles about 100 em in size) and resin consolidation (forming bulk material). Post-processing modifications aim at increasing wear resistance and oxidation stability which are regarded as major factors involved in TJR failure. In order to maintain high purity materials for medical application, it is not allowed to use additional chemicals during the modification processes. The only exception is the use of vitamin E, a natural stabilizer and antioxidant. Considering all the above mentioned facts, the modifications can be based on (I) ionizing radiation such as gamma rays or accelerated electrons, (II) thermal modification, (III) additional stabilization with vitamin E, and (IV) sterilization. According to the modifications, we usually differentiate three generations of UHMWPE. The 1st generation UHMWPE is not modified except for obligatory sterilization. The sterilization procedures based on chemical procedures (formaldehyde vapours, hot water) have lately been forbidden, abandoned and replaced by gamma-irradiation with doses of 25-45 kGy. In the course of time, sterilization by means of gamma-irradiation showed to be unsuitable due to oxidative degradation of UHMWPE, which resulted in lower wear resistance, worse material properties and a decrease in longevity of joint replacements. The 2nd generation UHMWPE or highly cross-linked UHMWPE is material treated with ionizing radiation (gamma-rays or accelerated electrons) at higher doses (usually 50-100 kGy). The irradiation is followed by thermal treatment in order to eliminate residual radicals and limit oxidative degradation that occurs in the 1st generation UHMWPE types. Finally, the material is sterilized usually by modern procedures using ethylene oxide or gas plasma neither of which causes oxidative degradation (as opposed to gamma-irradiation sterilization). The 3rd generation UHMWPE is basically the same as that of the 2nd generation. The main difference consists in slightly better mechanical properties (strength, fatigue) and further stabilization to oxidative degradation. This is achieved by special procedures, some of which are either controversial (sequential irradiation) or well-accepted by a great majority of the orthopaedic community (vitamin E stabilization). Only the future will show whether the difference between the 2nd and 3rd generations of UHMWPE will play any role in increasing TJR longevity and therefore the quality of its performance. The final objective of all of UHMWPE modifications is, as already mentioned, to increase wear resistance, oxidative resistance and mechanical performance of the polymer. These changes, especially an increase in wear resistance, have been confirmed to prolong the longevity of total joint replacements based on UHMWPE.

Bone grafts as vancomycin carriers in local therapy of resistant infections.

The level of an antibiotic capable of inhibiting the etiological agent at the site of infection is an essential prerequisite for successful antibiotic therapy. In some cases, locally applied antibiotics may compensate for limitations of systemic administration and shorten systemic therapy. We aimed at verifying to what extent vancomycin (Van) bound to ground bone grafts is usable in the treatment of serious infections. The levels of released Van significantly exceeded the Van minimum inhibitory concentration, which can suppress Van-sensitive staphylococci and Van intermediate Staphylococcus aureus, for the whole period of a 16-day measurement. Our results indicate that bone grafts can be used as Van carriers in therapy of osteomyelitis caused by Van-sensitive Staphylococcus strains.

[Giant cutaneous basal cell carcinoma of the head with intracranial propagation--a case report]. / "Gigantický" bazocelulárny karcinóm koze hlavy s intrakraniálnou propagáciou--kazuistika.

Basal cell carcinoma (BCC) of the skin is generally characterised by a favourable clinical outcome. The slow and mostly local character of growth helps in its early recognition, thus the vast majority of cases are diagnosed in the early phase of disease. However, in cases of long-term neglect of clinical symptoms, certain cancers may reach huge proportions and may significantly destroy surrounding tissue. BCCs larger than 5 cm are called giant BCCs. The authors of the article present a case report of woman suffering from a giant BCC of the head with a history of 15 years of lasting growth, during which she had refused a medical examination. Finally, she was forced to go into hospital due to episodes of unconsciousness and convulsions. Clinical investigations revealed a huge ulcerating tumour in the fronto-parietal region infiltrating the skull and penetrating into the cranial cavity with compression of the brain. A surgical extirpation of the tumor-affected soft tissue and the calva was performed with plastic reconstruction of dura mater and skin. Microscopic examination of biopsy specimens confirmed a diagnosis of mixed BCC with nodular, infiltrative and metatypical features, which had completely infiltrated calva and dura mater. It was not possible to surgically remove a part of the tumour-affected bones of the left orbita, thus the patient is going to undergo local radiotherapy. This case report emphasizes the fact that BCC, in spite of its usually "benign" biological behaviour, should never be underestimated because it may progress to the advanced stage of the disease, for which treatment is much more difficult with a larger negative impact and a significantly worse prognosis for the patient.

[Cement-within-cement femoral stem reimplantation technique]. / Reimplantace náhrady kycelního kloubu metodou docementování dríku do puvodního cementového luzka.

PURPOSE OF THE STUDY: The reimplantation of a cemented femoral component at revision is always a challenge for the orthopaedic surgeon, particularly when the cement mantle is intact. The aim of this study was to provide evidence that the recementing of a femoral stem into the original cement mantle can be included in routine surgical procedures. MATERIAL AND METHODS: A group of 104 patients with femoral stem revision, followed-up for an average of 50.2 months, were retrospectively reviewed. The outcome evaluation was focused, in the first place, on survivorship of the femoral component, acetabular migration, and dislocation and infection after revision arthroplasty. Hip function evaluation was based on the Harris hip scores before surgery and at the latest follow-up. On radiographs Gruen zones were assessed pre-operatively and at the latest follow-up. The results were statistically evaluated using the Kaplan-Meier survival analysis (Statistica 8.0). RESULTS: Of the 104 patients, only three (2.9 %) had stem re-revision due to its loosening. Further 16 patients underwent revision for other post-operative complications. The success rate of reimplantation in our group including all post-operative complications was 81.7 %. The average Harris scores were 56 before surgery and 87 at the latest follow-up. Radiolucent lines in Gruen zones were on average 0.45 mm in width before revision and 0.15 mm at the latest follow-up. Fourteen patients had second revision within 20 months of the first and only five were revised after a long period. DISCUSSION: The cement-within-cement exchange of a femoral component is a relatively frequent orthopaedic procedure. Despite this frequency, however, there have not been enough literature reports based on large patient groups to give support to its routine use. The aim of this study was to demonstrate on a large patient group that recementing a femoral stem into the original intact cement mantle can be considered an established operative technique. Our results suggest that the list of indications for this technique, as described by Lieberman and Nelson, can be extended by the following: broken stem with an intact distal cement mantle, replacement of a monoblock femoral component due to severe head damage, loosening of the femoral component without impairment of the distal cement mantle, conversion of a cervico-capital to a total hip replacement and the need of removing all bone cement. No risk is associated with reimplantation of the original component if there is no need for a different implant to correct angle or length stability. A new implant is always used when any part of the femoral component has been damaged mechanically. If only the proximal stem requires recementing, the use of the original component is preferred because of absolute cement/stem cohesion. The number of our patients in which the technique failed was generally in agreement with the results of other authors. CONCLUSIONS: Utilisation of the original cement mantle of a femoral component is one of the options at revision arthroplasty. It requires rational considerations based on the type of surgery, state of the cement mantle, and type of material used for the femoral stem. The method is indicated preferably in the hips with an intact cement mantle treated for loosening of the acetabular component, recurrent dislocation or unequal leg-length in monoblock femoral components. In such situations the removal of well-fixed cement would also involve a considerable loss of bone tissue. The follow-up outcomes showed that the involvement of the cement-within-cement technique in routinely used surgical procedures is fully justified.

[MORF method for assessment of the size and shape of UHMWPE wear microparticles and nanoparticles in periprosthetic tissues]. / Metoda MORF pro sledování velikostí a tvaru oterových mikro- a nanocástic UHMWPE v periprotetických tkáních.

PURPOSE OF STUDY: Aseptic loosening of total joint replacement (TJR) due to wear of ultra-high molecular weight polyethylene (UHMWPE) is regarded as one of the major problems in the field of arthroplasty. This work describes a newly developed method, called MORF, which completely describes the morphology of UHMWPE wear particles. The differences in wear particle morphology may help to elucidate individual differences in TJR failures. MATERIAL AND METHODS: During the years 2002-2010, a set of 47 typical damaged periprosthetic tissues, coming from 16 TJR revisions, was collected. Isolated on polycarbonate (PC) filters were quantified. Quantification of the particles consisted in determination of their concentration and description of their morphology by means of the newly developed MORF method. Firstly, the micrographs of isolated UHMWPE particles were obtained with a scanning electron microscope (Quanta 200 FEG; FEI) at two magnifications: x1200 and x6000. Secondly, both high- and low-magnification micrographs were processed by a standard image analysis software (program NIS Elements; Laboratory Imaging) in order to obtain basic morphological descriptors. Finally, the results from image analysis of high- and low- magnification micrographs were combined by means of our own program MDISTR in order to obtain correct particle sizes and shapes. RESULTS: In the first stage, the method was applied to 25 samples and yielded an average particle size of 0.51 µm. In the second stage, the method was further improved in order to calculate not only the size of particles but also the shape of descriptors. The improved method was applied to eight samples and gave an average size of particles (equivalent diameter, D) in the range of 0.27 - 0.60 µm, circularity (C) of 0.66-0.85 and elongation (E) of 1.75-1.79, suggesting that the great majority of particles were approximately spherical. Finally, in the third stage, the MORF method was applied to two exceptional samples which contained extremely small wear particles (D = 18.5 nm and 21.2 nm). The shape of these small wear nano- particles (C = 0.97 and 0.93; E = 1.29 and 1.35) was even more spherical than that of wear microparticles described abo- ve. This was one of the first two studies which proved the presence of UHMWPE wear nanoparticles in vivo. DISCUSSION: Our newly developed MORF method described in this contribution yields both size and shape descriptors of UHMWPE wear particles, with sizes from 0.1 to 10 µm, which are regarded as most biologically active. The main objective of the method is to yield the highest accuracy. This is achieved by parallel analyses of high- and low-magnification micrographs taken of the same sample. In the end, the two analyses are combined together in order to obtain the correct and complete size and shape description of all particles in the sample. The morphology of UHMWPE wear particles influences TJR lifetime both directly (size and shape of the particles is related to their biological activity) and indirectly (for the given total volumetric wear, size and shape of the particles influence their concentration, which is associated with the biological respon- se of the organism). CONCLUSION: The authors have developed a new method which yields a complete description of the size and shape of UHMWPE wear particles in periprosthetic tissues. The method, which was called MORF, can be applied to studies of TJR failures and also used to evaluate the quality of different UHMWPE components of TJR. The method is quite universal and therefore can be used not only for analyses of wear particles, but also for other types of particles, such as microparticles in polymer blends or inorganic/metallic nanoparticles.

[Comparison of in vivo characteristics of polyethylene wear particles produced by a metal and a ceramic femoral component in total knee replacement]. / Srovnání oterových charakteristik polyetylenu in vivo u náhrad kolena s kovovou a keramickou femorální komponentou.

PURPOSE OF THE STUDY: The aim of the study was to evaluate in vivo and compare, in terms of the quality and number of ultra high-molecular polyethylene (UHMWPE) wear particles, total knee replacements of identical construction differing only in the material used for femoral component production, i.e., CoCrMo alloy or ZrO2 ceramics. MATERIAL AND METHODS: Samples of peri-prosthetic granuloma tissue were collected in two patients with total knee replacement suffering from implant migration, who were matched in relevant characteristics. The primary knee replacement in Patient 1 with a CoCrMo femoral component was done 7.2 years and in Patient 2 with a ZrO2 implant 6.8 years before this assessment. The polyethylene wear-induced granuloma was analysed by the MORF method enabling us to assess the shape and size of wear debris and the IRc method for assessment of particle concentration. RESULTS: In the granuloma tissue samples of Patient 1, on the average, particles were 0.30 mm in size and their relative volume was 0.19. In the Patient 2 tissue samples, the average size of particles was 0.33 mm and their relative volume was 0.26. There was no significant difference in either particle morphology or their concentration in the granuloma tissue between the two patients. DISCUSSION: One of the options of how to reduce the production of polyethylene wear particles is to improve the tribological properties of contacting surfaces in total knee replacement by substituting a cobalt-chrome femoral component with a zirconia ceramic femoral component. The previous in vitro testing carried out with a mechanical simulator under conditions approaching real weight-bearing in the human body did show a nearly three-fold decrease in the number of UHMWPE wear particles in zirconia components. The evaluation of granuloma tissue induced by the activity of a real prosthetic joint for nearly seven years, however, did not reveal any great difference in either quality or quantity of polyethylene debris between the two replacements. The difference of surface roughness between CoCrMo (Ra = 0.05) and ZrO2 (Ra = 0.02) components did not play any role in in vivo conditions. CONCLUSIONS In accordance with a previous clinical study, this evaluation of the quality and quantity of UHMWPE wear particles produced by a ceramic femoral component in vivo failed to demonstrate any advantage of zirconia ceramic components over the cobalt-chrome femoral components so far used.