Aim. Antibacterial activity of coatings based on metal and metal oxide nanoparticles (NPs) often depends on materials and biotic targets resulting in a material-specific killing activity of selected Gram-positive and Gram-negative bacteria, including drug-resistant strains. In this perspective, the NPs loading amount, the relative elemental concentration inside the nanogranular building blocks and the deposition method are of paramount importance when the goal is to widen the antimicrobial spectrum, but at the same time to avoid high levels of metal content to limit undesired toxic effects. Aim of the present study was evaluation of the antimicrobial properties of two multielement nanogranular coatings composed of Titanium-Silver and Copper and of Magnesium-Silver and Copper. Method. Ti-Ag-Cu and Mg-Ag-Cu NPs were deposited on circular cover glasses (VWR) by Supersonic Cluster Beam Deposition. Biofilm-producer strains of Staphylococcus aureus (methicillin susceptible and resistant), Staphylococcus epidermidis (methicillin susceptible and resistant), Escherichia coli (fully susceptible and producer of extended spectrum beta lactamases), and Pseudomonas aeruginosa (susceptible and multidrug-resistant) were selected. The abilities of the selected strains to adhere, colonize and produce biofilm on the discs coated with Ti-Ag-Cu or Mg-Ag-Cu NPs were compared to uncoated circular cover glasses which were used as growth control. Cytotoxicity was also evaluated in order to assess the biocompatibility of the newly synthesized NPs. Results. In comparison to uncoated controls, both coatings showed significant anti-adhesive properties against S. aureus, S. epidermidis, and E. coli. Reduction in adhesion to Mg-Ag-Cu coated discs was observed also for P. aeruginosa isolates, although differences vs uncoated controls did not reach statistical significance. Biofilm formation was reduced on discs coated with Mg-Ag-Cu compared to Ti-Ag-Cu and, again, coatings had a milder effect on P. aeruginosa, probably due to its exceptional capability of attachment and matrix production. These results were confirmed by the evaluation of bacterial colonization on nanoparticles-coated discs by means of confocal laser scanning microscopy. A viability of 95.8% and 89.4% of cells cultured in the presence of Ti-Ag-Cu and Mg-Ag-Cu discs, respectively, when compared to negative controls was observed, thus excluding cytotoxic effects on eukaryotic cells. Conclusions. The newly synthesized Ti-Ag-Cu and Mg-Ag-Cu coatings are able to limit bacterial adhesion colonization and biofilm production, thus highlighting the safe use of multi-element families of NPs as new strategies against bacterial attachment to the surface of biomedical implants. However, further studies addressing activity against P. aeruginosa and including a wide number of isolates are warranted

Patient perceptions regarding the functional outcomes and return to sports after shoulder replacement are often pessimistic, with many patients presenting for shoulder replacement surgery after months or years of avoiding the procedure so they could continue to live the current life they have, despite the increasing pain and dysfunction. Less common, but becoming more frequent, patients present with expectations that they will be able to return to all activities including heavy resistance training, cross-fit, rock climbing, and other strenuous overhead sports. In the past, little information has been available regarding the activities of shoulder arthroplasty patients after surgery. Typically, the boundaries have been set by the surgeon, with many patients cautioned or even prohibited from overhead sports, weight training, or heavy work responsibilities. A typical set of guidelines may include no repetitive overhead sports, except for recreational swimming, and no lifting over 20 pounds. Golf, jogging, hiking and other activities are allowed. The origin of these restricted guidelines and expectations is unknown, but many believe that since the results of shoulder replacements are less favorable in younger patients, it may be due to the overuse or abuse of the shoulder joint that is more typical at a younger age. Others have suggested that common sense prevails and that an artificial joint made of metal and plastic has a finite number of total movements and tolerance to resistance activities, and therefore keeping these activities at a minimum would extend the longevity of the artificial joint. None of these concepts are backed up by evidence-based literature, essentially reflecting the personal bias of the surgeons who care for patients with these problems. Despite all of the sophisticated research, scoring scales, outcome measures, and value-based metrics, the only outcome that really matters is whether the patient can return back to their normal way of life, at home, at work, during sport, or any activity that is important to them. Recent studies of patients who have had joint replacement surgery have revealed that our patients who participated in sports and work activities before surgery have a strong predilection to returning to those activities after successful shoulder replacement. The most common sports that shoulder arthroplasty patients enjoy including golf, swimming, tennis, but may also include many other choices including fitness activities, rowing, skiing, basketball, and softball. As expected, the return to these sports is less for reverse shoulder arthroplasty patients vs. anatomic shoulder arthroplasty patients. In a systematic review, more than 90% of anatomic shoulder replacement patients returned to sport, while 75% of reverse shoulder arthroplasty patients returned to some sporting activity. This may reflect the constraints of the reverse prosthesis, or, quite possibly reflect the typically older age and more sedentary lifestyle of patients who are indicated for reverse shoulder arthroplasty. In addition, if the patient had a preoperative expectation of return to recreational and sports activities as part of their normal way of life, their final results demonstrated better overall outcomes. Shoulder arthroplasty surgeons should be concerned about the outcomes desired by our patients, and the results that provide true value to their lives. We are now more aware of the activities that they are going to return to, whether we recommend restrictions or not

Although the impact of sexual difficulties on quality of life in patients with hip osteoarthritis has been documented in previous literature, recent research has shown that surgeons rarely discuss this sensitive topic with patients. The purpose of this study was to develop an educational tool to address common questions that patients may have regarding returning to sexual activity following their total hip arthroplasty (THA). The study was conducted in two phases. In Phase 1, patients who underwent a THA between 2013–2017 at a single centre were retrospectively identified and sent an anonymous online survey. This survey was aimed at assessing patient-specific concerns regarding whether they would have liked to receive information about returning to sexual activity, what information they would have liked to know and how they would have liked to receive this information. An educational tool was developed based on the findings of Phase 1. In Phase 2, prospective patients who were scheduled for a unilateral or bilateral THA were provided with the educational tool prior to their surgery. A questionnaire was administered to evaluate the effectiveness of this educational tool. Descriptive statistics and chi-squared tests were used for data analysis. In Phase 1, the overall response rate was 34.7% (n = 58/167). Out of the total respondents, 51.7% indicated an interest in receiving information on when to return to sexual activity following a THA. Patients selected an informational pamphlet as the most desired method of receiving information (p = .044). In Phase 2, the response rate was 54.5% (n = 30/55). Overall, 90% of patients felt that the pamphlet addressed all their concerns, and 93.3% felt they were provided with adequate information on how they could get more information. The pamphlet addressed questions regarding when it was safe to resume sexual activity following a THA, what positions were safe, and the associated risks. Individuals undergoing a THA are modestly interested in receiving information regarding when to return to sexual activity following their surgery, especially those who are sexually active preoperatively. This educational pamphlet may be useful in routine clinical practice in addressing concerns regarding returning to sexual activity. Understanding patients' goals and expectations for their postoperative course may help surgeons provide a more comprehensive approach to patient care

Introduction. Gait laboratory measurement of whole-body kinematics and ground reaction forces during a wide range of activities is frequently performed in joint replacement patient diagnosis, monitoring, and rehabilitation programs. These data are commonly processed in musculoskeletal modeling platforms such as OpenSim and Anybody to estimate muscle and joint reaction forces during activity. However, the processing required to obtain musculoskeletal estimates can be time consuming, requires significant expertise, and thus seriously limits the patient populations studied. Accordingly, the purpose of this study was to evaluate the potential of deep learning methods for estimating muscle and joint reaction forces over time given kinematic data, height, weight, and ground reaction forces for total knee replacement (TKR) patients performing activities of daily living (ADLs). Methods. 70 TKR patients were fitted with 32 reflective markers used to define anatomical landmarks for 3D motion capture. Patients were instructed to perform a range of tasks including gait, step-down and sit-to-stand. Gait was performed at a self-selected pace, step down from an 8” step height, and sit-to-stand using a chair height of 17”. Tasks were performed over a force platform while force data was collected at 2000 Hz and a 14 camera motion capture system collected at 100 Hz. The resulting data was processed in OpenSim to estimate joint reaction and muscle forces in the hip and knee using static optimization. The full set of data consisted of 135 instances from 70 patients with 63 sit-to-stands, 15 right-sided step downs, 14 left-sided step downs, and 43 gait sequences. Two classes of neural networks (NNs), a recurrent neural network (RNN) and temporal convolutional neural network (TCN), were trained to predict activity classification from joint angle, ground reaction force, and anthropometrics. The NNs were trained to predict muscle and joint reaction forces over time from the same input metrics. The 135 instances were split into 100 instances for training, 15 for validation, and 20 for testing. Results. The RNN and TCN yielded classification accuracies of 90% and 100% on the test set. Correlation coefficients between ground truth and predictions from the test set ranged from 0.81–0.95 for the RNN, depending on the activity. Predictions from both NNs were qualitatively assessed. Both NNs were able to effectively learn relationships between the input and output variables. Discussion. The objective of the study was to develop and evaluate deep learning methods for predicting patient mechanics from standard gait lab data. The resulting models classified activities with excellent performance, and showed promise for predicting exact values for loading metrics for a range of different activities. These results indicate potential for real-time prediction of musculoskeletal metrics with application in patient diagnostics and rehabilitation. For any figures or tables, please contact authors directly

Smartphone-based apps that measure step-count and patient reported outcomes (PROMs) are being increasingly used to quantify recovery in total hip arthroplasty (THA). However, optimum patient-specific activity level before and during THA early-recovery is not well characterised. This study investigated 1) correlations between step-count and PROMs and 2) how patient demographics impact step-count preoperatively and during early postoperative recovery. Smartphone step-count and PROM data from 554 THA patients was retrospectively reviewed. Mean age was 64±10yr, BMI was 29±13kg/m2, 56% were female. Mean daily step count was calculated over three time-windows: 60 days prior to surgery (preop), 5–6 weeks postop (6wk), and 11–12 weeks postop (12wk). Linear correlations between step-count and HOOS12 Function and UCLA activity scores were performed. Patients were separated into three step-count levels: low (<2500steps/day), medium (2500-5500steps/day), and high (>5500steps/day). Age >65years, BMI >30, and sex were used for demographic comparisons. Student's t-tests determined significant differences in mean step-counts between demographic groups and in mean PROMs between step-count groups. UCLA correlated with step-count at all time-windows (p<0.01). HOOS12 Function correlated with step-count preoperatively and at 6wk (p<0.01). High vs low step count individuals had improved UCLA scores preoperatively (∆1.8,p<0.001), at 6wk (∆1.1,p<0.05), and 12wk (∆1.6,p<0.01), and improved HOOS12 Function scores preoperatively (∆8.4,p<0.05) and at 6wk (∆8.8,p<0.001). Younger patients had greater step-count preoperatively (4.1±3.0k vs 3.0±2.5k, p<0.01) and at 12wk (5.1±3.3k vs 3.6±2.9k, p<0.01). Males had greater step-count preoperatively (4.1±3.0k vs. 3.0±2.7k, p<0.001), at 6wk (4.5±3.2k vs 2.6±2.5k, p<0.001), and at 12wk (5.2±3.6k vs. 3.4±2.5k, p<0.001). Low BMI patients had greater step-count at 6wk (4.3±3.3k vs. 2.6±2.7k, p<0.01) and 12wk (5.0±3.6k vs. 3.6±2.6k, p<0.05). Daily step-count is significantly impacted by patient demographics and correlates with PROMs, where patients with high step count exhibit improved PROMs. Generic recovery profiles may therefore not be appropriate for benchmarking across diverse populations

Passive smartphone-based apps are becoming more common for measuring patient progress after total knee arthroplasty (TKA). Optimum activity levels during early TKA recovery haven't been well documented. This study investigated correlations between step-count and patient reported outcome measures (PROMs) and how demographics impact step-count preoperatively and during early post-operative recovery. Smartphone capture step-count data from 357 TKA patients was retrospectively reviewed. Mean age was 68±8years. 61% were female. Mean BMI was 31±6kg/m2. Mean daily step count was calculated over three time-windows: 60 days prior to surgery (preop), 5-6 weeks postop (6wk), and 11-12 weeks postop (12wk). Linear correlations between step-count and KOOS12-function and UCLA activity scores were performed. Patients were separated into three step-count levels: low (<1500steps/day), medium (1500-4000steps/day), and high (>4000steps/day). Age >65years, BMI >30kg/m2, and sex were used for demographic comparisons. Student's t-tests determined significant differences in mean step-counts between demographic groups, and in mean PROMs between step-count groups. UCLA correlated with step-count at all time-windows (p<0.01). KOOS12-Function correlated with step-count at 6wk and 12wk (p<0.05). High step-count individuals had improved PROMs compared to low step-count individuals preoperatively (UCLA: ∆1.4 [p<0.001], KOOS12-Function: ∆7.3 [p<0.05]), at 6wk (UCLA: ∆1 [p<0.01], KOOS12-Function: ∆7 [p<0.05]), and at 12wk (UCLA: ∆0.8 [p<0.05], KOOS12-Function: ∆6.5 [p<0.05]). Younger patients had greater step-count preoperatively (3.8±3.0k vs. 2.5±2.3k, p<0.01), at 6wk (3.1±2.9k vs. 2.2±2.3k, p<0.05) and at 12wk (3.9±2.6k vs. 2.8±2.6k, p<0.01). Males had greater step-count preoperatively (3.7±2.6k vs. 2.5±2.6k, p<0.001), at 6wk (3.6±2.6k vs. 1.9±2.4k, p<0.001), and at 12wk (3.9±2.3 vs. 2.8±2.8k, p<0.01). No differences in step-count were observed between low and high BMI patients at any timepoint. High step count led to improved PROMs scores compared to low step-count. Early post-operative step-count was significantly impacted by age and sex. Generic recovery profiles may not be appropriate across a diverse population

The aim of the this study was to determine the effect of the knee flexion angle (KFA) during tibial anterior cruciate ligament (ACL) graft fixation on patient reported outcomes, graft stability, extension loss and re-operation following anatomic single-bundle ACL reconstruction. All 169 included patients (mean age 28.5 years, 65% male) were treated with anatomic single bundle ACL reconstruction using patellar tendon autograft and randomized to tibial fixation of the ACL graft at either 0o (n=85) or 30o (n=84). The primary outcome was the Knee Injury and Osteoarthritis Outcome Score (KOOS) two years following surgery. Secondary outcomes were the Marx Activity Scale (MAS), the rate of re-operation, and physical exam findings at one year including KT-1000 and side to side differences in knee extension. The follow-up rate was 82% (n=139) for the primary outcome. Graft failure rate at two years was 1% (n=2, 1 per group). ACL tibial graft fixation at 0o or 30o did not have a significant effect on KOOS scores at two years following ACLR. Patients whose graft was fixed at a knee flexion angle of 0o had greater scores on the Marx Activity Scale (mean 9.6 [95%CI 8.5-10.6] versus 8.0 [95%CI 6.9-9.1, p=0.04) and a greater proportion of patients who achieved the minimal clinical important difference (MCID) for the KOOS pain subscale (94% vs 81%, p=0.04). There was no significant difference in knee extension loss, KT-1000 measurements or re-operation between the two groups. In the setting of anatomic single-bundle ACLR using patellar tendon autograft and anteromedial portal femoral drilling, there was no difference in KOOS scores among patients fixed at 0o and 30o. Patient fixed in full extension did demonstrate higher activity scores at 2 years following surgery and a greater likelihood of achieving the MCID for KOOS pain

Many patients who undergo a total knee arthroplasty (TKA) wish to return to a more active lifestyle. The implant must be able to restore adequate muscle strength and function. However, this may not be a reality for some patients as quadriceps and hamstrings muscle activity may remain impaired following surgery. The purpose of this study was to compare muscle activity between patients implanted with a medial pivot (MP) or posterior stabilized (PS) implant and controls (CTRL) during ramp walking tasks. Fifteen patients were assigned to either a MP (n=9) or PS (n=6) TKA operated by the same surgeon. Nine months following surgery, the 15 patients along with nine CTRL patients completed motion and EMG analysis during level, ramp ascent & descent walking tasks. Wireless EMG electrodes were placed on six muscles: vastus medialis (VM), vastus lateralis (VL), biceps femoris (BF), semimembranosus (SM) muscles, gastrocnemius medial head (GM), and gastrocnemius lateral head (GL). Participants completed three trials of each condition. EMG data were processed for an entire gait cycle of the operated limb in the TKA groups, and for the dominant limb in the CTRL group. The maximum muscle activity achieved with each muscle during the level trial was used to normalize the ramp trials. The onset and offset of each muscle was determined using the approximated generalized likelihood ratio. Peak muscle activity (PeakLE), total muscle activity (iEMG), and muscle onsets/offsets were determined for each muscle for the ramp ascent and descent trials. Non-parametric Kruskal Wallace tests were used to test for statistical significance between groups with α=0.05. During the ramp up task, both MP and PS groups had significantly greater PeakLE and iEMG for the hamstring muscles compared to the CTRL, whereas the PS group had significantly greater PeakLE compared with the MP group for the SM muscle. During the ramp down task, both MP and PS groups had significantly greater PeakLE and iEMG for the SM and GL muscles compared to the CTRL. The PS group also had significantly greater iEMG for the BF and VM muscles compared to the CTRL. The MP group had a significantly earlier offset for the SM muscle compared to the CTRL. Stability in a cruciate removing TKA is partially controlled by the prosthetic design. During the ramp up task, the TKA groups compensated the tibial anterior translation by activating their hamstrings more and for a longer duration. The MP group required less hamstrings activation than the PS group. During the ramp down task, TKA patients stiffened their knee in order to stabilize the joint. The quadriceps, hamstrings and GL muscle were activated more and for a longer duration than the CTRL group to protect the tibial posterior translation. The PS group required greater BF and VM iEMG than the MP group. Even if surgery reduced pain, differences in muscle activity exist between TKA patients and healthy controls. The prosthetic design provides some stability to the knee, and the MP implant required less muscle activation than the PS implant to stabilize the knee joint

The age spectrum for patients undergoing shoulder arthroplasty is broadening. Many younger patients now demonstrate shoulder pathology precluding non-arthroplasty reconstruction. The senior population is living longer and “younger”. Therefore, the demands of this patient population to participate in an active lifestyle are growing. Patients with osteoarthritis, cuff tear arthropathy, post-traumatic arthropathy, avascular necrosis, and even forms of inflammatory arthropathy present seeking not only return to simple activities of daily living but the ability to participate in aerobic recreational activities and even work activities which can stretch the limits of shoulder arthroplasty in the physiologic environment of the shoulder. This presentation will provide an overview of patient demands, concerns and activity level following shoulder arthroplasty. We will provide a prospective of allowable, recommended and discouraged activities depending on the underlying source of pathology in the type of arthroplasty implants employed. An overview of our four phases of rehabilitation protocol will be presented focusing on phase four, “work in sports hardening”

Aim. Here, we are aimed to evaluate bacteriophage (191219) to treat S. aureus implant-associated bone infections by means of testing against S. aureus during its planktonic, biofilm and intracellular growth phases and finally assessing antimicrobial effect on in vivo biofilm formed on metal K-wire in an alternative insect model Galleria mellonella. Method. The bacteriophages (191219) were provided from D&D Pharma GmbH. These bacteriophages were tested against S. aureus EDCC 5055 (MSSA) and S. aureus DSM 21979 (MRSA) strains. To assess the activity of bacteriophages against planktonic growth phase, bacteriophages, and S. aureus EDCC 5055(1×10. 7. CFU/ml) were co-cultured in LB media as multiplicity of infection (MOI) of 10, 1, 0.1, and 0.01 for 24 hours at 37. o. C and finally plated out on the LB agar plates to estimate the bacterial growth. The antimicrobial activity of bacteriophages on biofilms in vitro was measured by analysing the incubating the several fold dilutions of bacteriophages in LB media with biofilms formed on 96-well plate. The eradication of biofilm was analysed with crystal violet as well as CFU analysis methods. Later, the effect of bacteriophages on intracellular growth of S. aureus in side osteoblast was tested by treating the S. aureus infected osteoblasts at 2h, 4h and 24h time points of post treatment. In addition, we have analysed synergistic effect with gentamicin and rifampicin antibiotics to clear intracellular S. aureus. Finally, experiments are performed to prove the effect of bacteriophages to clear in vivo biofilm using alternative insect model G. mellonella as well as to detect the presence of bacteriophages inside the osteoblasts through transmission electron microscopy (TEM) analysis. Results. Our results demonstrate the in vitro efficacy of bacteriophages against planktonic S. aureus. Transmission electron microscopy (TEM) experiments revealed severe infection of bacteria by bacteriophages. Bacteriophages also eradicated in a dose-dependent manner in vitro S. aureus biofilm formation and were active against intracellular S. aureus in an osteoblastic cell line. TEM analysis visualized the effect of the bacteriophages on S. aureus inside the osteoblasts with the destruction of the intracellular bacteria and formation of new bacteriophages. For the Galleria infection model, single administration of phages failed to show improvement in survival rates, but exhibited some synergistic effects with gentamicin or rifampicin, which was not statistically significant. Conclusions. In summary, bacteriophages could be a potential adjuvant treatment strategy for patients with implant-associated biofilm infections. Further preclinical and clinical trials are required to establish adequate treatment protocols

Introduction. Unicompartmental knee arthroplasty is in particular promoted for knee OA patients with high demands on function and activity. This study used wearable inertial sensors to objectively assess function during specific motion tasks and to monitor activities of daily living to verify if UKA permits better function or more activity in particular with demanding tasks. Methods. In this retrospective, cross-sectional study, UKA patients (Oxford, n=26, 13m/13f, age at FU: 66.5 ±7.6yrs) were compared to TKA patients (Vanguard, n=26, 13m/13f, age: 66.0 ±6.9yrs) matched for gender, age and BMI (29.5 ±4.6) at 5 years follow-up. Subjective evaluation of pain, function, physical activity and awareness of the joint arthroplasty was performed by means of four PROMs: VAS pain, KOOS-PS, SQUASH (activity) and Forgotten Joint Score (FJS),. Objective measurement of function was performed using a 3D inertia sensor attached to the sacrum while performing gait test, sit-stand and block-step tests. To derive functional parameters such as walking cadence or sway during transfers or step-up previously validated algorithms were used (Bolink et al., 2012). Daily physical activity was objectively monitored with a 3D accelerometer attached to the lateral side of the unaffected upper leg during four consecutive days. Activity parameters (counts and times of postures, steps, stairs, transfers, etc.) were also derived using validated algorithms. Data was analysed using independent T-test, Mann-Whitney U test and Pearson's correlation. Results. PROM's did not show any significant difference between UKA and TKA especially for the routinely used VAS-Pain and KOOS-PS (p>0.57) while higher (better) mean scores were recorded for UKA using more specialist measures such as self-reported activity (SQUASH; UKA vs TKA: 5659 ±3753 vs 4245 ±2489, p=0.12) and joint awareness (FJS; UKA vs TKA: 50.7 ±24.3 vs 41.4 ±29.2, p=0.08). Sensor based measures of function showed significantly higher walking cadence for UKA (107.9 ±10.5 steps/min) than TKA (102.2 ±10.9 steps/min, p=0.049). Other functional parameters also indicated better UKA function, e.g. forward sway during sit-stand (UKA vs TKA: 38.0 ±13.2 deg vs 43.2 ±10.7 deg, p=0.06). The wearable activity monitors showed that UKA patients perform significantly more steps downwards on stairs or slopes (89.0 ±77.4) than TKA patients (46.9 ±51.3, p=0.03). Other, less demanding activity counts such as daily steps (6522 vs 6343, p=0.85) or sit-stand transfers (39.4 vs 42.3, p=0.37) were not different. Discussion and Conclusion. PROM's could not differentiate UKA from TKA although more specialist or demanding scores such SQUASH (activity) or FJS (joint awareness) seem to have more power. Objective assessment could show for UKA faster cadence and more steps down on stairs and slopes, indicating that UKA benefits functional quality and enables demanding activities. Objective measures of function and activity may be required in routine clinical follow-up to provide evidence and wearable sensors may facilitate this

Posterior stabilized (PS) total knee arthroplasty (TKA), wherein mechanical engagement of the femoral cam and tibial post prevents abnormal anterior sliding of the knee, is a proven surgical technique. However, many patients complain about abnormal clicking sensation, and several reports of severe wear and catastrophic failure of the tibial post have been published. In addition to posterior cam-post engagement during flexion, anterior engagement with femoral intercondylar notch can also occur during extension. The goal of this study was to use dynamic simulations to explore sensitivity of tibial post loading to implant design and alignment, across different activities. LifeModeler KneeSIM software was used to calculate tibial post contact forces for four contemporary PS implants (Triathlon PS, Stryker; Journey BCS and Legion PS, Smith & Nephew; LPS Flex, Zimmer Biomet). An average model of the knee, including cartilage and soft tissue insertion locations, created from MRI data of 40 knees was used to mount and align the component. The Triathlon femoral component was mounted with posterior and distal condylar tangency at: a) both medial and lateral condylar cartilage (anatomic alignment), b) at the medial condylar cartilage and perpendicular to mechanical axis (mechanical alignment with medial tangency), and c) at lateral condylar cartilage and perpendicular to mechanical axis (mechanical alignment with lateral tangency). The influence of implant design was assessed via simulations for the other implant systems with the femoral components aligned perpendicular to mechanical axis with lateral tangency. Five different activities were simulated. The anterior contact force was significantly smaller than the posterior contact force, but it varied noticeably with tibial insert slope and implant design. For Triathlon PS, during most activities anatomic alignment of the femoral component resulted in greater anterior contact force compared to mechanical alignment, but absolute magnitude of forces remained small (<100N). Mechanical alignment with medial tangency resulted in greater posterior contact force for deep knee bend and greater anterior force for chair sit activity. For all implants, peak posterior contact forces were greater for activities with greater peak knee flexion. The magnitude of posterior contact forces for the various implants was comparable to other reports in literature. Overall activity type, implant design and slope had greater impact on post loading than alignment method. Tibial insert slope was shown to be important for anterior post loading, but not for posterior post loading. Anatomic alignment could increase post loading with contemporary TKA systems. In the case of the specific design for which effect of alignment was evaluated, the changes in force magnitude with alignment were modest (<200N). Nonetheless, results of this study highlight the importance of evaluating the effect of different alignment approaches on tibial post loading

There is increased awareness of the health benefits of regular exercise, and quantifying daily activity has become popular. Consequently, there are an increasing number of devices for measuring physical activity. Healthcare professionals and the general public should know the accuracy and limitations of these devices to better determine which ones suit their needs. Ten devices were tested: one ankle-based device, StepWatch™ Activity Monitor (SAM); two wrist-based devices, FitBit Force™ and Nike+ Fuelband SE; seven waist-based devices, Omron HJ-321 Pedometer, Sportline 340 Strider Pedometer, FitBit One™, Samsung Galaxy S4 utilizing the two most popular applications (Runtastic and Noom Walk), and the iPhone 5 utilizing the two most popular applications (Runtastic and ARGUS). Thirty healthy volunteers, mean age 25.6 years (range 20–30) and mean body mass index 23.5 (range 17.3–29.0), completed the following protocol: (1) walk briskly around a 400-M track simulating community ambulation (2) jog around a 400-M track (3) walk slowly for 10-M, approximating household or workplace pace (4) ascend 10 steps, and (5) descend 10 steps. Each subject completed 3 trials for each task. Manual count was the gold standard (Champion Sports Tally Counter). Accuracy and mean percent error were calculated to demonstrate overall performance and any tendencies for over or undercounting. An Aggregate Accuracy Score was calculated using the mean accuracy of each activity and multiplying by a corresponding weighted value for a prototypical person: 400-M walk represents community ambulation, weighted 40%; 10-M walk represents household and workplace ambulation, weighted 30%; 400-M jog represents jogging or running, weighted 20%; Stair Ascent and Descent represent community and household stair use, weighted 5% each. Device rank based on the Aggregate Accuracy Score was #1 FitBit One™ (98.0%), #2 Omron HJ-321 (97.0%), #3 StepWatch™ Activity Monitor (93.3%), #4 Runtastic Google App (92.7%), #5 Runtastic iPhone App (89.5%), #6 Fitbit Force™ (88.2%), #7 Argus iPhone App (87.2%), #8 Sportline 340 Strider (85.7%), #9 Nike Fuelband (76.1%), #10 Noom Walk Google App (75.9%). The FitBit One™ was 99.5%, 97.8%, 96.7%, 94.3%, and 96.9% accurate in the 400-M walk, 10-M walk, 400-M jog, 10 stair ascent, and 10 stair descent, respectively. The Omron HJ-321 was 99.3%, 94.9%, 97.9%, 92.2%, and 91.3% accurate, respectively. The SAM performed well (>95% accurate) in all activities except one, consistently undercounting the 400-M jog by about 25% (95% CI: −27.2% – −23.9%). The FitBit ForceTM and Nike+ Fuelband SE wrist devices were ≥90% accurate in the 400-M walk and 400-M jog, but ≤83% accurate for all other activities. Three of the 4 smartphone applications were >97% accurate in the 400-M walk, 1 of 4 was 97.3% accurate in the 400-M jog, but all devices performed poorly (≤90% accurate) for all other activities. Smartphones are very popular, but current technology is less accurate for measuring overall daily activity. The relatively inexpensive FitBit One™ and Omron HJ-321 pedometer are highly accurate for quantifying a variety of activities, including running. The StepWatch™ Activity Monitor performs well in lower cadence, but consistently undercounted jogging. Wrist-based activity devices are not as accurate as waist-based. Next generation technologies, including smartphones, should undergo accuracy testing before recommending them for daily use

Introduction. The systematic effects of joint replacement in rheumatoid arthritis (RA) patients are that inflamed synovium and pathological articular cartilage has dissipated. Expectations of total knee arthroplasty (TKA) are reduction of inflammatory cytokines, decreased disease activity and improvement of drug efficacy and ADL. Remission of rheumatoid arthritis is defined as having a Disease Activity Score DAS28 (ESR) of less than 2.6 and Health Assessment Questionnaire (HAQ) – Disability Index, less than 0.5. Purpose. We investigated whether TKA could reduce disease activity and improve ADL, and subsequent remission levels of DAS and HAQ or not. Material and Methods. We analyzed the Knee Society Score (KSS), KOOS score and DAS28 in 15 patients, 23 rheumatoid arthritic knees at pre-operation and 1 year after operation. Preoperatively patients had used non-steroidal anti-inflammatory drugs, prednisolone, disease-modifying anti-rheumatic drugs including methotrexate. TKA (Zimmer NexGen LPS Flex Knee implants and Stemmed Tibial component with stem) was performed with the modified gap technique or modified anatomical technique using original tensor with synovectomy. Results. Preoperative and postoperative KSS are 45.7±18.1 and 88.7±17.7 (P<0.01) respectively, and function scores were 40.1±21.7 and 74.8±24.0 (P<0.01) respectively (Figure 1). Preoperative and postoperative KOOS score (%) were ‘pain’ 50.6±37.8 and 95.4±19.3 (P<0.01), ‘symptom’ 56.6±32.8 and 94.7±18.6 (P<0.01), ‘ADL’ 60.6±27.9 and 89.5±32.4 (P<0.01), ‘QOL’ 28.4±32.1 and 63.6 ±22.9 (P<0.01) and ‘sport’ 20.56±29.52 and 47.10±33.9(P=0.06), respectively (Figure 2). Preoperative and postoperative DAS28(CRP) were 4.48±1.08 and 3.58±1.11(P<0.01), and DAS28 (ESR) were 4.90±1.02 and 4.13±0.99 (P=0.02) (Figure 3). Discussion. Each scores except ‘sport’ and DAS28 (ESR) improved statistically 1 year after operation. Function score, ‘ADL’ and ‘QOL’ scores also improved. HAQ score includes 2 categories related to walking ability and TKA was expected to improve the HAQ score, although the HAQ score is highly affected by upper arm function. The ‘sport’ score did not improve because almost all patients did not do sports preoperatively and postoperatively. DAS28 (ESR) and DAS28 (CRP) correlate strongly, but in this study there were statistical discrepancies in improvement. This might be because age, sex, disease duration, and existence of rheumatoid factors, anti-cyclic citrullinated peptide antibody and DLA-DRB1 shared epitope have been shown to influence ESR. DAS28 improved by a little less than 1.0, but there was limited control of disease activity. It was reported that the average DAS 28 didn't drop below 3.2 in 3 years follow-up after TKA. In this study we did not assess depending on preoperative disease activity, but it was reported that TKA had a systematic effect on severe or moderate RA activity, not low disease activity

“How does the knee move?” is a question of fundamental importance for treatment of knee injuries and knee replacement design. Unfortunately, we lack unambiguous and comprehensive knee function data sets and/or consensus on how healthy knees move. One can just as easily find reports stating the natural knee has a center of axial rotation in the medial compartment of the knee as in the lateral. This is due to technical and practical issues: It is extremely difficult to accurately measure knee motions during ambulatory activities and, when that can be done, very few studies have examined a range of weightbearing activities in the same study cohort. The purpose of this study is to report knee kinematics in a cohort of healthy older subjects whose motions were examined during four different movements, three of them weightbearing ambulation, using a high-speed stereoradiographic system. Six healthy consenting subjects (age = 61 ± 5 years, body mass = 75 ± 8 kg, BMI = 27 ± 4) were observed using a high-speed stereoradiographic system while completing four tasks. Subjects were instructed to perform an unloaded, seated knee extension from high flexion to full extension; to walk at a self selected pace; to step down from a 7 inch platform; and to walk and perform a 90° direction change (pivoting). Stereoradiographic images (1080 × 1080 pixels) were acquired at 100 images/second using 40cm image intensifiers and pulsed x-ray exposures. The three-dimensional knee kinematics were measured using the XROMM software suite (. xromm.org. , Brown University). Post-processing of the kinematics was performed in custom Matlab programs, and included fitting spheres to the posterior condylar surfaces of each knee, and then tracking the motions of the sphere centers relative to a fixed tibial reference frame (Figure 1). The motions of these flexion-facet centers, were used to determine an average center of axial rotation (CoR) over each activity as previously reported by Banks and Hodge. Average CoRs for all four activities were in the posterior-medial quadrant of the knee, with the CoR for open-chain knee extension being the most medial and gait the most lateral (Table 1, Figure 2). One-way ANOVA showed average CoRs are different (p « 0.001). There was considerable variation in individual CoRs, for example, with two knees showing lateral CoRs for gait and the remaining knees having medial CoRs. It should not be surprising that natural knee motions vary with dynamic activity, yet knee kinematics often are presented as being one stereotypic, monolithic pattern of motion. Our data show that the same healthy subjects performing different dynamic activities manifest different knee motions, with open-chain knee extension having the most medial CoR and gait the most lateral. This finding is consistent with previous reports comparing stair climbing and gait in knees with various implant designs. Additional experimental data and, ultimately, validated numerical simulations should facilitate an increasingly accurate process for designing improved treatments for diseased and damaged knees

Increasing pressure to use rapid recovery care pathways when treating patients undergoing total hip arthroplasty (THA) is evident in current health care systems for numerous reasons. Patient autonomy and health care economics has challenged the ability of THA implants to maintain functional integrity before achieving bony union. Although collared stems have been shown to provide improved axial stability, it is unclear if this stability correlates with activity levels or results in improved early function to patients compared to collarless stems. This study aims to examine the role of implant design on patient activity and implant fixation. The early follow-up period was examined as the majority of variation between implants is expected during this time-frame. Patients (n=100) with unilateral hip OA who were undergoing primary THA surgery were recruited pre-operatively to participate in this prospective randomized controlled trial. All patients were randomized to receive either a collared (n=50) or collarless (n=50) cementless femoral stem. Patients will be seen at nine appointments (pre-operative, < 2 4 hours post-operation, two-, four-, six-weeks, three-, six-months, one-, and two-years). Patients completed an instrumented timed up-and-go (TUG) test using wearable sensors at each visit, excluding the day of their surgery. Participants logged their steps using Fitbit activity trackers and a seven-day average prior to each visit was recorded. Patients also underwent supine radiostereometric analysis (RSA) imaging < 2 4 hours post-operation prior to leaving the hospital, and at all follow-up appointments. Nineteen collared stem patients and 20 collarless stem patients have been assessed. There were no demographic differences between groups. From < 2 4 hours to two weeks the collared implant subsided 0.90 ± 1.20 mm and the collarless implant subsided 3.32 ± 3.10 mm (p=0.014). From two weeks to three months the collared implant subsided 0.65 ± 1.54 mm and the collarless implant subsided 0.45 ± 0.52 mm (p=0.673). Subsidence following two weeks was lower than prior to two weeks in the collarless group (p=0.02) but not different in the collared group. Step count was reduced at two weeks compared to pre-operatively by 4078 ± 2959 steps for collared patients and 4282 ± 3187 steps for collarless patients (p=0.872). Step count increased from two weeks to three months by 6652 ± 4822 steps for collared patients and 4557 ± 2636 steps for collarless patients (p=0.289). TUG test time was increased at two weeks compared to pre-operatively by 4.71 ± 5.13 s for collared patients and 6.54 ± 10.18 s for collarless patients (p=0.551). TUG test time decreased from two weeks to three months by 7.21 ± 5.56 s for collared patients and 8.38 ± 7.20 s for collarless patients (p=0.685). There was no correlation between subsidence and step count or TUG test time. Collared implants subsided less in the first two weeks compared to collarless implants but subsequent subsidence after two weeks was not significantly different. The presence of a collar on the stem did not affect patient activity and function and these factors were not correlated to subsidence, suggesting that initial fixation is instead primarily related to implant design

Both the patient and the surgeon want hip and knee arthroplasties to last a lifetime. As a result, many patients have been told to defer arthroplasty as long as possible. After arthroplasty, many patients have been advised to limit physical activity. Such management strategies prioritise longevity but compromise lifestyle. Given that the technical aspects of the arthroplasty are satisfactory, modern total hip and knee prostheses have demonstrated remarkable durability. Quantitative studies of patient activity have measured up to 48 million cycles in-vivo, with impact, without evidence of loosening, osteolysis, or other impending failure. These data suggest that with current technology, an active lifestyle is compatible with implant longevity

Aim. The increase of antimicrobial resistance reduces treatment options for implant-associated infections caused by methicillin-resistant Staphylococcus aureus (MRSA). Bacteriophages present a promising alternative to treat biofilm-related infections due to their rapid bactericidal activity and activity on multi-drug resistant bacteria. In this study, we investigated the synergistic activity of lytic bacteriophage Sb-1 with different antibiotics against MRSA biofilm, using a real-time highly sensitive assay measuring growth-related heat production (microcalorimetry). Methods. Rifampin, fosfomycin, vancomycin and daptomycin were tested alone and in combination with S. aureus specific phage, Sb-1, against MRSA (Staphylococcus aureus*). MRSA biofilm was formed on porous glass beads (Φ 4 mm, pore size 60 µm) and incubated for 24 h at 37° C in BHI. After 3 times washing biofilms were exposed first to different titers of bacteriophages, ranging from 102 to104 plaque-forming unite (pfu)/ml and after 24h treated again with subinhibitory concentration of antibiotics (corresponding to 1/4, 1/8, 1/16, 1/32 × MHICbiofilm). After 24h antibiotic treatment, the presence of biofilm on glass beads was evaluated by isothermal microcalorimetry for 48h. Heat flow (µW) and total heat (J) were measured. Results. MHICs of rifampin, fosfomycin, daptomycin and vancomycin when tested alone were 256 μg/ml, >4096 μg/ml, 128μg/ml and 2048μg/ml, respectively. Synergistic activity against biofilm MRSA was observed when vancomycin was tested at subinhibitory concentrations 512 μg/ml, 256 μg/ml, 128 μg/ml and 64 μg/ml in combination with subinhibitory titers of Sb-1 at 102, 103, 104 pfu/ml. Complete inhibition of heat production was observed only in combination with a higher titer of Sb-1 (104 pfu/ml). High synergistic activities were also observed in the presence of rifampin, fosfomycin and daptomycin. Conclusions. While MHICs of antibiotics against MRSA biofilm were above drug concentrations reachable in clinical practice, the co-administration with bacteriophage Sb-1 strongly reduced the antibiotic doses needed to eradicate MRSA biofilm. The use of bacteriophage and antibiotics in combination represent an effective strategy to treat implant-associated infections

Introduction. The sit-to-stand (STS) movement is a physically demanding activity of daily living and is performed more than 50 times per day in healthy adults. Several studies have shown that the normal ‘screw-home’ mechanism is altered after total knee arthroplasty (TKA). However, these studies have been criticized due to their limitations of the movement being non-weight-bearing or atypical daily activity (lunge maneuver). We analyzed TKA subjects during a STS activity to determine if the internal-external rotation of their TKA knees differed from the knees of control subjects. Materials and Methods. Six TKA subjects (3 M, 3 F) participated following institutional review board approval and informed consent. One subject had bilateral knee replacement. Surgery was performed by the same surgeon using the same type of implant (6 posterior-stabilized, 1 cruciate-retaining). The control group included eight healthy subjects (6 M, 2 F). Retro-reflective markers were placed over bony landmarks of the torso, pelvis, and lower extremities, and arrays of four markers were attached to the thighs and shanks using elastic wrap. A digitizing pointer was used to create virtual markers at the anterior superior iliac spines. A nine camera video-based opto-electronic system (Qualisys) was used for 3D motion capture. Subjects were barefoot and seated on a 46 cm armless bench with one foot on each force plate (AMTI). Subjects rose from their seated position, paused, and returned to the seated position at a self-selected pace repeatedly for 30 seconds. Subjects did not use their arms to push off the bench. Only the STS portion of the task was analyzed. The start of the STS cycle was defined when the C7 marker began to move forward in the sagittal plane and ended at the point of maximum knee extension. Only the right leg of the control subjects was used for analysis. Results. Femurs rotated internally as control subjects rose from the bench. Two of the TKA knees displayed a similar pattern of internal rotation as the knees extended. However, four TKA knees displayed the opposite pattern, and one TKA knee showed no rotation. For ease of comparison I/E rotation was normalized to zero at full extension (Figure 1). Discussion. Our results of a reverse tibio-femoral rotational pattern in TKA knees compared to normal knees are similar to those reported in fluoroscopic studies in which a single leg lunge activity is performed. Finding a similar reversal in STS is significant due to the necessity and frequency of the STS activity during daily living and warrants further investigation

Introduction. The purpose of this study was to characterize the recovery of physical activity following knee arthroplasty by means of step counts and flight counts (flights of stairs) measured using a smartphone-based care platform. Methods. This is a secondary data analysis on the treatment cohort of a multicenter prospective trial evaluating the use of a smartphone-based care platform for primary total and unicondylar joint arthroplasty. Participants in the treatment arm that underwent primary total or unicondylar knee arthroplasty and had at least 3 months of follow-up were included (n=367). Participants were provided the app with an associated smart watch for measuring several different health measures including daily step and flight counts. These measures were monitored preoperatively, and the following postoperative intervals were selected for review: 2–4 days, 1 month, 1.5 month, 3 months and 6 months. The data are presented as mean, standard deviation, median, and interquartile range (IQR). Signed rank tests were used to assess the difference in average of daily step counts over time. As not all patients reported having multiple stairs at home, a separate analysis was also performed on average flights of stairs (n=214). A sub-study was performed to evaluate patients who returned to preoperative levels at 1.5 months (step count) and 3 months (flight count) using an independent samples T test or Fisher's Exact test was to compare demographics between patients that returned to preoperative levels and those that did not. Results. The mean age of the step count population was 63.1 ± 8.3 years and 64.31% were female, 35.69% were male. The mean body mass index was 31.1 ± 5.9 kg/m. 2. For those who reported multiple stairs at home, the mean age was 62.6 ± 8.3 years and 62.3% were female. The mean body mass index was 30.7 ± 5.4 kg/m. 2. . As expected, the immediate post-op (2–4 days) step count (median 1257.5 steps, IQR 523 – 2267) was significantly lower than preop (median 4160 steps, IQR 2669 – 6034, p < 0.001). Approximately 50% of patients returned to preoperative step counts by 1.5 months postoperatively with a median 4,504 steps (IQR, 2711, 6121, p=0.8230, Figure 1). Improvements in step count continued throughout the remainder of follow-up with the 6-month follow-up visit (median 5517 steps, IQR 3888 – 7279) showing the greatest magnitude (p<0.001). In patients who reported stairs in their homes, approximately 64% of subjects returned to pre-op flight counts by 3 months (p=0.085), followed similar trends with significant improvements at 6 months (p=0.003). Finally, there was no difference in age, sex, BMI, or operative knee between those that returned to mean preoperative step or flight counts by 1.5 months and 3 months, respectively. Discussion and Conclusion. These data demonstrated a recovery curve similar to previously reported curves for patient reported outcome measures in the arthroplasty arena. Patients and surgeons may use this information to help set goals for recovery following total and unicondylar knee arthroplasty using objective activity measures. For any figures or tables, please contact the authors directly