After total knee arthroplasty, 10–30

The aim of our study is to evaluate clinical long-term results and determine changes in periprosthetic bone density of the custom-made hip prostheses Evolution-K® and Adaptiva®. Periprosthetic bone density were evaluated by means of DEXA (LunariDXA- Prodigy® bone densitometer) with a long-term follow-up of 16 (15-18) years (Evolution-K®) in 24 patients and 13 (13-15) years (Adaptiva®) in 41 patients. Evolution- K® had a survival rate of 92% and yielded 79/100 points in Harris Hip Score, a mediocre result. Adaptiva® had a survival rate of 99% and achieved a good score of 88/100 points. Bone density measurements demonstrated the greatest loss of bone density in the proximal regions of interest (ROI) for both prosthesis types (Evolution-K®: -25.8% ROI 1, -40.3% ROI 7; -8.3% ROI 2, -10.4% ROI 6; Adaptiva®: -29.8% ROI 7, -6.8% ROI 6, +14.3% ROI 3, +3.1% ROI 4). Adaptiva® yielded a good clinical result as compared to Evolution-K® with only average clinical results. Both prostheses clearly showed signs of “stress shielding”. Here, the Adaptiva® achieved reduced bone density loss as compared to the Evolution-K®.

IntroductionPersistent anterior knee pain, subluxation or dislocation of the patella as well as early aseptic loosening and increased polyethylene wear of the patella implant are common clinical problems after total knee arthroplasty (TKA) which are associated with the patellofemoral joint. In addition to patellar resurfacing, the design of the patellofemoral joint surfaces is attributed a large influence. While for patients without patella resurfacing, the native patella is sliding on the standardized femoral component and therefore the possibility of a reduced surface matching is high, patella resurfacing has been shown to decrease the joint contact area and yield to increased patellofemoral pressure. With regard to a further design optimization, the current study examined patellar biomechanics after TKA without and with resurfacing, comparing 5 differently designed patellofemoral joint surfaces of the femoral implant.MethodsThe femoral implant of the Genesis II prosthesis (Smith & Nephew) was scanned a...

OBJECTIVE:To analyze the potential of the dual outer diameter screw and systematically evaluate the pull-out force of the dual outer diameter screw compared to the uncemented and cemented standard pedicle screws with special regard to the pedicle diameter and the vertebra level.METHODS:Sixty vertebrae of five human spines (T 6 -L 5 ) were sorted into three study groups for pairwise comparison of the uncemented dual outer diameter screw, the uncemented standard screw, and the cemented standard screw, and randomized with respect to bone mineral density (BMD) and vertebra level. The vertebrae were instrumented, insertion torque was determined, and pull-out testing was performed using a material testing machine. Failure load was evaluated in pairwise comparison within each study group. The screw-to-pedicle diameter ratio was determined and the uncemented dual outer diameter and standard screws were compared for different ratios as well as vertebra levels.RESULTS:Significantly increased pull-out forces were measured for the cemented standard screw compared to the uncemented standard screw (+689 N, P < 0.001) and the dual outer diameter screw (+403 N, P < 0.001). Comparing the dual outer diameter screw to the uncemented standard screw in the total study group, a distinct but not significant increase was measured (+149 N, P = 0.114). Further analysis of these two screws, however, revealed a significant increase of pull-out force for the dual outer diameter screw in the lumbar region (+247 N, P = 0.040), as well as for a screw-to-pedicle diameter ratio between 0.6 and 1 (+ 488 N, P = 0.028).CONCLUSIONS:For clinical application, cement augmentation remains the gold standard for increasing screw stability. According to our results, the use of a dual outer diameter screw is an interesting option to increase screw stability in the lumbar region without cement augmentation. For the thoracic region, however, the screw-to-pedicle diameter should be checked and attention should be paid to screw cut out, if the dual outer diameter screw is considered.

In total knee arthroplasty (TKA), patellofemoral groove design varies greatly and likely has a distinct influence on patellofemoral biomechanics. To analyse the selective influence, five patellofemoral design variations were developed based on Genesis II total knee endoprosthesis (original design, being completely flat, being laterally elevated, being medially elevated, and both sides elevated) and made from polyamide using rapid prototyping. Muscle-loaded knee flexion was simulated on 10 human knee specimens using a custom-made knee simulator, measuring the patellofemoral pressure distribution and tibiofemoral and patellofemoral kinematics. The measurements were carried out in the native knee as well as after TKA with the 5 design prototypes. The overall influence of the different designs on the patellofemoral kinematics was small, but we found detectable effects for mediolateral tilt (p<0.05 for 35°–80° flexion) and translation of the patella (p<0.045 for 20°–65° and 75°–90°), especially for the completely flat design. Considering patellofemoral pressures, major interindividual differences were seen between the designs, which, on average, largely cancelled each other out. These results suggest that the elevation of the lateral margin of the patellofemoral groove is essential for providing mediolateral guidance, but smooth contouring as with original Genesis II design seems to be sufficient. The pronounced interindividual differences identify a need for more patellofemoral design options in TKA.

ABSTRACT Objective: Infection after total hip (THA) and knee arthroplasty (TKA) is a serious complication which typically leads to a long lasting and intensive surgical and medicamentous treatment. The aim of this study was to identify factors that influence outcome after revision surgery caused by prosthetic infection. Methods: We retrospectively analyzed 64 patients who had revision surgery between 1989 and 2009 due to periprosthetic infection. We examined a total of 69 joints (TKA: 36%, THA: 64%), follow-up 5.1 years (0.5-21 years) after the initial surgical intervention. The mean patient age at time of surgery was 67 years old (43-79 years old). Clinical data and scores including the Western Ontario and McMaster Universities (WOMAC)-Index, the Harris Hip Score (HHS) and the Hospital for Special Surgery Score (HSS) were surveyed. Results: There was no difference in clinical scores regarding treatment between a single and a multiple stage treatment regime. Infections with multiple microorganisms and Enterococcus spp. lead to a significantly higher number of interventions. Using a modified Tsukayama system we classified 24% as type I, 34% type II and 42% type III- infections, with no differences in clinical outcome. Overweight patients had a significantly lower HHS and WOMAC-score. Immunosuppression leads to a worse WOMAC and HSS-Score. An increased number of procedures was associated to a limping gait. Conclusion: Thorough surgical technique leads to good clinical results independent of infection-type and treatment philosophy. Level of Evidence III, Case Control Study.

Background: Anterior cruciate ligament rupture can lead to symptomatic instability, especially during pivoting activities, which are often associated with increased anterior and rotational tibial loading. Therefore, the purpose of our robot-aided in-vitro study was to analyze the influence of tibial rotation on anterior knee stability under three anterior cruciate ligament conditions.Methods: Ten human knee specimens were examined using a robotic system. Anterior tibial translations were measured during anterior force application at internally and externally rotated positions of the tibia (5 steps until 4 Nm was reached) at 20 degrees, 60 degrees, and 90 degrees of flexion. The native knee was compared with the knee with deficient and replaced anterior cruciate ligamentFindings: Tibial rotation significantly influenced anterior tibial translation (P < 0.001), with differences of up to 12 mm between the largest and smallest anterior translation in the deficient knee. The largest influence of the anterior cruciate ligament on anterior translation was found in slightly externally rotated positions of the tibia (5 degrees-10 degrees at 20 degrees of flexion; 0 degrees-5 degrees at 90 degrees of flexion). Significantly increased anterior tibial translation (up to 7 mm) was measured after anterior cruciate ligament resection, which could be almost completely restored by the replacement (remaining difference < 1 mm) over a wide range of tibial rotations.Interpretation: Tibial rotation clearly influences anterior tibial translation. Because the greatest effect of the anterior cruciate ligament was found in slightly externally rotated positions of the tibia, increased attention to tibial rotation should be paid when performing the Lachman and anterior drawer tests. (C) 2015 Elsevier Ltd. All rights reserved.

Anterior Cruciate Ligament (ACL) rupture is one of the most common sport injuries [1]. While the importance of the cruciate ligaments for stabilization of the knee in anteroposterior (AP) direction is evident, their influence on rotational knee stability is still discussed controversially, especially since the doublebundle technique for ACL replacement claims the advantage of improved rotational stability [2,3]. Patients after ACL rupture often report symptomatic knee instability and giving way, especially during fast cutting and pivoting activities. During these activities, enhanced internal and external rotations occur in addition to anterior and posterior loading of the knee. Therefore, the aim of the current study was to systematically analyze the influence of tibial rotation on AP stability of the knee, comparing different conditions of the cruciate ligaments.

For the analysis of different treatments concerning anterior cruciate ligament (ACL) rupture, objective methods for the quantification of knee stability are needed. Therefore, a new method for in-vivo stability measurement using a robotic testing system should be developed and evaluated.

Anterior knee pain is often associated with patellar maltracking and instability. However, objective measurement of patellar stability under clinical and experimental conditions is difficult, and muscular activity influences the results. In the present study, a new experimental setting for in vitro measurement of patellar stability was developed and the mediolateral force–displacement behavior of the native knee analyzed with special emphasis on patellar tilt and muscle loading.

BACKGROUND AND OBJECTIVES: Despite the recommendations of national and international societies for the treatment of patients with acute neck and back pain, still too many radiologic examinations were performed. The purpose of this study was to analyze and optimize diagnostics and treatment of patients with acute back pain.METHODS: The medical records of 484 patients presented to the emergency clinic with acute neck or back pain were analyzed for clinical history, physical examination, radiographic findings and therapy.RESULTS: Radiographs of the lumbar, cervical, or thoracic spine were performed in 338 cases (70%). Radiographs were normal in 142 patients (42%) and degenerative changes were identified in 123 patients (36%). Only 2 patients (0.4%) had radiographic findings that had direct therapeutic relevance: 1 patient with metastatic disease and 1 patient with posttraumatic C1-C2 instability. For most patients without sensorimotor deficits and absent specific indications for radiography ("red flags"), therapy was not affected by the results of radiography.CONCLUSIONS: Plain radiography of the spine was unnecessary in most patients initially evaluated with non-specific acute back pain and does not improve the clinical outcome. The implementation of national and international guidelines is a slow process, but helps to reduce costs and to protect patients from unnecessary ionizing radiation exposure.

Osteochondral autologous transplantation is frequently used to repair small cartilage defects. Incongruence between the osteochondral graft surface and the adjacent cartilage leads to changed friction and contact pressure. The present study wanted to analyze the differences between intact and surgically treated cartilage surface in respect to contact pressure and frictional characteristic (dissipated energy). Six ovine carpometacarpal joints were used in the present study. Dissipated energy during instrumentally controlled joint movement as well as static contact pressure were measured in different cartilage states (intact, defect, deep-, flush-, high-implanted osteochondral graft and cartilage failure simulation on a high-implanted graft). The best contact area restoration was observed after the flush implantation. However, the dissipated energy measurements did not reveal an advantage of the flush implantation compared to the defect and deep-implanted graft states. The high-implanted graft was associated with a significant increase of the mean contact pressure and decrease of the contact area but the dissipated energy was on the level of intact cartilage in contrast to other treatments where the dissipated energy was significantly higher as in the intact state. However the cartilage failure simulation on the high-implanted graft showed the highest increase of the dissipated energy.

Considering the discrepant results of the recent biomechanical studies, the purpose of this study was to simulate dynamic muscle-loaded knee flexion with a large number of specimens and to analyse the influence of total knee arthroplasty (TKA) without and with patellar resurfacing on the patellofemoral pressure distribution.

You have accessJournal of UrologyStone Disease: New Technology1 Apr 20131550 NANOTECHNOLOGY: 1.2F BASKETS FURTHER ENHANCE IRRIGATION FLOW IN FLEXIBLE URETERORENOSCOPY Stephan Kruck, Ulf Leichtle, Andrea Lorenz, Karl-Dietrich Sievert, Jens Bedke, and Arnulf Stenzl Stephan KruckStephan Kruck Tuebingen, Germany More articles by this author , Ulf LeichtleUlf Leichtle Tuebingen, Germany More articles by this author , Andrea LorenzAndrea Lorenz Tuebingen, Germany More articles by this author , Karl-Dietrich SievertKarl-Dietrich Sievert Tuebingen, Germany More articles by this author , Jens BedkeJens Bedke Tuebingen, Germany More articles by this author , and Arnulf StenzlArnulf Stenzl Tuebingen, Germany More articles by this author View All Author Informationhttps://doi.org/10.1016/j.juro.2013.02.3060AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookTwitterLinked InEmail INTRODUCTION AND OBJECTIVES Ureterorenoscopy (URS) has revolutionized upper urinary tract stone therapy. However, the size of the working channel and the stone baskets limit irrigation flow as well as vision during the application. Therefore, this study aimed to determine further improvements of irrigation flow and impairments of breaking resistance by the use of a new 1.2 French ultra-miniaturized basket. METHODS Irrigation flow measurements were performed in semirigid URS (semiURS, working channel 5F) and in flexible URS (flexURS, 3.6F) in 0°, 90° and 270° deflection with 1.2F, 1.8F, 1.9F and 2.2F baskets and compared to empty channel. Breaking strength of 1.2F, 1.8F and 1.9F baskets were evaluated using a material testing machine. RESULTS Tested baskets affected irrigation flow in semiURS and flexURS (p<0.05). Mean±SEM (standard error of the mean) for semiURS flow rates counted 197.1±2.0, 140.9±1.6, 111.1± 1.5, 98.0±1.3 and 77.1±0.9 ml/min for empty channel, 1.2F, 1.8F, 1.9F and 2.2F baskets (p<.0.05). Using unbent flexURS flow rates of 44.2±0.4, 20.4±0.2, 5.9±0.1, 5.4±0.1 and 1.5±0.1 ml/min for empty channel, 1.2F, 1.8F, 1.9F and 2.2F baskets, were observed (p<0.05). The 1.2F vs. 2.2F basket showed a 13.6-fold increase in flexURS irrigation (p<0.05). The breaking strength decreased with a reduced basket size (1.2F: 6.4±0.46 vs. 1.8F: 16.8±2.79 vs. 1.9F: 32.2±2.74 Newton, p<0.05). CONCLUSIONS Ultra-miniaturized baskets of 1.2F ensured a sufficient irrigation flow as needed for high quality vision in URS stone management. However, miniaturization of the 1.2F basket resulted in a reduced breaking strength compared to larger sized devices which in turn may hamper stone removal by an increased vulnerability. © 2013 by American Urological Association Education and Research, Inc.FiguresReferencesRelatedDetails Volume 189Issue 4SApril 2013Page: e635 Advertisement Copyright & Permissions© 2013 by American Urological Association Education and Research, Inc.MetricsAuthor Information Stephan Kruck Tuebingen, Germany More articles by this author Ulf Leichtle Tuebingen, Germany More articles by this author Andrea Lorenz Tuebingen, Germany More articles by this author Karl-Dietrich Sievert Tuebingen, Germany More articles by this author Jens Bedke Tuebingen, Germany More articles by this author Arnulf Stenzl Tuebingen, Germany More articles by this author Expand All Advertisement Advertisement PDF downloadLoading ...

Local adjuvant treatment of giant cell tumours (GCTs) of the bone with phenol has led to a significant reduction in recurrence rates. In the current study, the optimal phenol concentration and duration of intralesional exposure were evaluated. Specimens of GCTs were exposed to various concentrations of phenol solution (6, 60 and 80%) for either 1 or 3 min. Following embedding in glutaraldehyde, the tumour cell layers were examined by transmission electron microscopy. Destroyed cell organelles indicated the penetration depth as a sign of denaturation. Incubation of GCT specimens with 6% phenol solution for 3 min resulted in the most tissue damage and the deepest tissue penetration of ∼200 μm. Incubation with 60 and 80% phenol solution reached a penetration depth of only ∼100 μm. Phenol instillation may be used for the treatment of small scattered cellular debris following intralesional curettage; however, it is not suitable for treatment of remaining solid tumour tissue of GCT. The use of high phenol concentrations has no benefit and increases the risk of local or systemic intoxication.

Cartilage defects and osteoarthritis (OA) have an increasing incidence in the aging population. A wide range of treatment options are available. The introduction of each new treatment requires controlled, evidence based, histological and biomechanical studies to identify potential benefits. Especially for the biomechanical testing there is a lack of established methods which combine a physiologic testing environment of complete joints with the possibility of body-weight simulation. The current in-vitro study presents a new method for the measurement of friction properties of cartilage on cartilage in its individual joint environment including the synovial fluid.Seven sheep knee joints were cyclically flexed and extended under constant axial load with intact joint capsule using a 6 of freedom robotic system. During the cyclic motion, the flexion angle and the respective torque were recorded and the dissipated energy was calculated. Different mechanically induced cartilage defect sizes (16 mm(2), 50 mm(2), 200 mm(2)) were examined and compared to the intact situation at varying levels of the axial load. The introduced setup could significantly distinguish between most of the defect sizes for all load levels above 200 N. For these higher load levels, a high reproducibility was achieved (coefficient of variation between 4% and 17%).The proposed method simulates a natural environment for the analysis of cartilage on cartilage friction properties and is able to differentiate between different cartilage defect sizes. Therefore, it is considered as an innovative method for the testing of new treatment options for cartilage defects. (C) 2013 Elsevier Ltd. All rights reserved.

The aim of this study was to analyze the influence of the patellofemoral groove design in TKA on patellar kin ematics and pressures with a special regard to an individua l esign adaption. Five different designs of the patellofemo ral groove were created based on the Genesis II prosthesis. Mu cle loaded knee flexion was simulated on 10 human knee specimens while measuring the patellar kinematics a nd patellofemoral pressure distribution. For 3 specime ns, additional individual implants were developed based on CTscans. The largest influence was found for the completely flat design, where increased medal shift and lateral til t were measured after TKA compared to the native knee. The ot r designs only showed small differences. Therefore, a moderate groove should be sufficient to guarantee s able motion. Considering the patellofemoral peak pressu re, on average the designs only had a small effect, althou g large individual differences were found. The individually adapted designs did not show an improvement, which might be attributed to the alteration of overall knee biomec hanics during TKA. Therefore, an individual choice between different standard implants might be a good option.

Although mid- to long-term results after total ankle replacement have improved because of available second- and third-generation devices, failure of total ankle replacement is still more common compared with total hip replacement and total knee replacement . The portfolio of available total ankle replacement revision component options is small. Furthermore, the bone stock of the tibiotalar region is scarce making it difficult and in some situations impossible to perform revision total ankle replacement. In these cases tibiotalar and tibiotalocalcaneal fusions are valuable options. This article describes which surgical procedures should be performed depending on the initial situation and gives detailed advice on surgical technique, postoperative care, and clinical results.