Objective. We performed total knee arthroplasty (TKA) without patella resurfacing in patients with osteoarthritis (OA) of the knee. The purpose of the present study was to evaluate the clinical results and the appropriateness TKA without patella resurfacing. Methods. A total of 61 patients (61 affected knees) who had undergone a Low Contact Stress mobile − bearing knee arthroplasty (LCS− TKA) (Depuy, Warsaw, IN. USA) 10 years or more before the present study were enrolled. The LCS− TKAs did not include patella resurfacing. The patients' mean age was 77.7 ± 6.1 years (range: 59−94 years). The mean follow-up period was 121 ± 2.4 months (range: 120−129 months). The clinical evaluation used the scoring system for OA of the knees issued by the Japanese Orthopaedic Association (JOA score). We defined patellofemoral (PF) pain, crepitation, patellar clunk syndrome, spin-out, and reoperation as complications. We also used X-Ray imaging to measure the component angle, patella height, lateral shift ratio, tilting angle, femorotibial angle, posterior condylar offset and joint line, and evaluated the localization of sclerotic changes in the patella. All of the LCS− TKAs were performed by one surgeon using the midvastus approach. During the operation, the osteophyte around the patella was resected, and the osteophyte on the articular surface was shaped using a bone saw. For statistical analysis we performed Mann-Whitney's U test and adopted a significance level of P<5%. Results. The average JOA score improved significantly from 46.2 ± 10.4 before the LCS− TKA to 82.6 ± 6.1 after the LCS− TKAs (P = 0.0002). No cases of patellar clunk syndrome or spin-out. occurred. Revision surgery was performed for two cases, one involved an infection, and the other involved a patella fracture. Postoperative PF pain was found in 6 patients (6 affected knees) at the final evaluation. However, in these patients, the pain was less severe than it had been preoperatively, and revision surgery for PF pain was needed or performed. The postoperative radiological evaluation was favorable on the whole. The localization of sclerotic changes in the patella on X-ray were in 32 cases around tip of the patella, on the other no remarkable change were in 29 cases. Conclusion. The clinical and radiological evaluations of the patella non−resurfacing mobile bearing total knee arthroplasty was favorable overall. Treatment of the patella in total knee arthroplasty remains controversial. We suggest that the patella in LCS−TKAs does not always need to be resurfaced

Introduction. For nearly 58% of total knee arthroplasty (TKA) revisions, the reason for revision is exacerbated by component malalignment. Proper TKA component alignment is critical to functional outcomes/device longevity. Several methods exist for orthopedic surgeons to validate their cuts, however, each has its limitations. This study developed/validated an accurate, low-cost, easy to implement first-principles method for calculating 2D (sagittal/frontal plane) tibial tray orientation using a triaxial gyroscope rigidly affixed to the tibial plateau of a simulated leg jig and validated 2D tibial tray orientation in a human cadaveric model. Methods. An initial simulation assessed error in the sagittal/frontal planes associated with all geometric assumptions over a range of positions (±10°, ±10°, and −3°/0°/+3° in the sagittal, frontal, and transverse planes, respectively). Benchtop experiments (total positions - TP, clinically relevant repeated measures - RM, novice user - NU) were completed using a triaxial gyroscope rigidly affixed to and aligned with the tibial tray of the fully adjustable leg-simulation jig. Finally, two human cadaveric experiments were completed. A similar triaxial gyroscope was mounted to the tibial tray of a fresh frozen human cadaver to validate sagittal and frontal plane tibial tray orientation. In cadaveric experiment one, three unique frontal plane shims were utilized to measure changes in frontal plane angle. In cadaveric experiment two, measurements using the proprosed gyroscopic method were compared with computer navigation at a series of positions. For all experiments, one rotation of the leg was completed and gyroscopic data was processed through a custom analysis algorithm. Results. Mathematical simulations showed that over the range of tested orientations, error from our geometric assumptions would be less than 1° and 0.2° in the sagittal and frontal planes, respectively. Results of all bench-top experiments are shown in Figure 1. The average angular error during the TP experiment (black bars) was 1.09°±0.80° and 0.60°±0.46° in the sagittal/frontal planes. The average angular error during the RM experiment (white bars) in the sagittal/frontal planes was 0.27°±0.25° and 0.30°±0.23°. The average angular error from the NU experiment (grey bars) in the sagittal/frontal planes was 1.50°±1.57° and 0.82°±0.77°. During cadaveric experiment one (Figure 2), computed frontal plane angles were 2.83°±0.98°, −1.67°±1.99°, and −4.33°±0.53° after placing distinct 2° lateral, 2° medial, and 4° medial shims. Finally, the average angular error from cadaveric experiment two (Figure 3) over all positions was 1.73°±1.12° and 1.56°±1.45° in the sagittal and frontal planes, respectively. Discussion. Despite the high frequency of TKA procedures, a significant number fail and need to be revised for improper component alignment. This study showed through a first-principles approach that surgeons can assess 2D orientation of the tibial component intraoperatively with 1° of accuracy with a single triaxial gyroscope rigidly affixed to the tibial plateau. Moreover, this study showed through the use of a cadaveric model that surgeons could assess 2D alignment of the tibial component with a gyroscope rigidly affixed to the tibial plateau. To our knowledge, this is first method to offer true 2D tibial tray orientation assessment using only a single triaxial gyroscope

PURPOSE. Total knee arthroplasty (TKA) is a successful technique for treating painful osteoarthritic knees. However, the patients' satisfaction is not still comparable with total hip arthroplasty. Basically, the conditions with operated joints were anterior cruciate ligament (ACL) deficient knees, thus, the abnormal kinematics is one of the main reason for the patients' incomplete satisfaction. Bi-cruciate stabilized (BCS) TKA was established to reproduce both ACL and posterior cruciate ligament (PCL) function and expected to improve the abnormal kinematics. However, there were few reports to evaluate intraoperative kinematics in BCS TKA using navigation system. Hence, the aim in this study is to reveal the intraoperative kinematics in BCS TKA and compare the kinematics with conventional posterior stabilized (PS) TKA. Materials and Methods. Twenty five consecutive subjects (24 women, 1 men; average age, 77 years; age range, 58–85 years) with varus osteoarthritis undergoing navigated BCS TKA (Journey II, Smith&Nephew) were enrolled in this study. An image-free navigation system (Stryker 4.0 image-free computer navigation system; Stryker) was used for the operation. Registration was performed after minimum medial soft tissue release, ACL and PCL resection, and osteophyte removal. Then, kinematics including tibiofemoral rotational angles from maximum extension to maximum flexion were recorded. The measurements were performed again after implantation. We compared the kinematics with the kinematics of paired matched fifty subjects who underwent conventional posterior stabilized (PS) TKA (25 subjects with Triathlon, Stryker; 25 subjects with PERSONA, ZimmerBiomet) using navigation statistically. Results. Preoperative tibiofemoral rotational kinematics were almost the same between the three implants groups. Kinematics at post-implantation found that tibia was significantly internally rotated compared to the kinematics at registration in all three implants at maximum extension position (p<0.05), however the tibial rotational position with BCS TKA was significantly externally rotated at maximum extension position, compared to the other two implant position (p<0.05). The tibial rotational position with Triathlon PS TKA was externally rotated at 60 degrees of flexion compared to the other two implant position, however the results were not statistically significant. Discussion and Conclusion. Previous study found that PCL resection changed tibial rotational position and the amount of tibial internal rotation, affecting postoperative maximum flexion angles. This study found that BCS TKA can reduce the amount of rotational changes, compared to conventional PS TKA. Further studies are needed to investigate the kinematic changes in BCS TKA affect the postoperative clinical outcomes

Purpose Of Study. The in vivo evaluation of patellofemoral contact pressures in a posterior stabilized compared to posterior cruciate sacrificing total knee arthroplasty (TKA). Methods. A prospective descriptive non randomized study was performed on 8 patients. A standard approach to a TKA was performed using a balanced gap technique, while the patella was prepared for a resurfacing. The trial components for the posterior stabilized (PS) TKA where inserted including the gas sterilized pressure transducer (a patella button). Soft tissue was approximated and the knee was taken through full range of movement. Patellofemoral pressure was measured and captured continuously through the full range of movement. The posterior cruciate sacrificing (CS) components were inserted into the same patient and the procedure repeated. In addition, anterior translation of the tibia relative to the femur was measured at 90 degrees. The transducer was removed and final components, including a patella resurfacing were inserted. Results. Significantly lower patella femoral pressures were found for PS TKA compared to CS TKA in full flexion [129.0 ± 21.7 N vs. 109.9 ± 32.1 (p = 0.038173)]. The change in patellofemoral pressure between flexion and extension was significantly lower in PS TKA compared to CS TKA [109.0 ± 21.6 N vs. 90.5 ± 32.0 (p = 0.0037690)]. In addition mean anterior translation at 90° flexion in the CS TKA (6.4 ± 3.2 mm) was significantly less than in PS TKA (17.0 ± 2.6) (p = 0.000072). Conclusion. Significantly lower patellofemoral pressures were found in full flexion with PS TKA compared to CS TKA. The change in patellofemoral pressure in a PS TKA compared to CS TKA was also significantly lower. This study provides possible clinical data when considering patella resurfacing. NO DISCLOSURES

To describe the longitudinal trends in patients with obesity and Metabolic Syndrome (MetS) undergoing TKA and the associated impact on complications and lengths of hospital stay.

We identified patients who underwent primary TKA between 2006 – 2017 within the American College of Surgeons National Surgical Quality Improvement Program (NSQIP) database. We recorded patient demographics, length of stay (LOS), and 30-day major and minor complications. We labelled those with an obese Body Mass Index (BMI ≥ 30), hypertension, and diabetes as having MetS. We evaluated mean BMI, LOS, and 30-day complication rates in all patients, obese patients, and those with MetS from 2006-2017. We used multivariable regression to evaluate the trends in BMI, complications, and LOS over time in all patients and those with MetS, and the effect of BMI and MetS on complication rates and LOS, stratified by year.

270,846 patients underwent primary TKA at hospitals participating in the NSQIP database. 63.71% of patients were obese (n = 172,333), 15.21% were morbidly obese (n = 41,130), and 12.37% met criteria for MetS (n = 33,470). Mean BMI in TKA patients increased at a rate of 0.03 per year (0.02-0.05; p < 0 .0001). Despite this, the rate of adverse events in obese patients decreased: major complications by an odds ratio (OR) of 0.94 (0.93-0.96; p < 0 .0001) and minor complications by 0.94 (0.93-0.95; p < 0 .001). LOS also decreased over time at an average rate of −0.058 days per year (-0.059 to −0.057; p < 0 .0001). The proportion of patients with MetS did not increase, however similar improvements in major complications (OR 0.94 [0.91-0.97] p < 0 .0001), minor complications (OR 0.97 [0.94-1.00]; p < 0 .0330), and LOS (mean −0.055 [-0.056 to −0.054] p < 0 .0001) were found. In morbidly obese patients (BMI ≥ 40), there was a decreased proportion per year (OR 0.989 [0.98-0.994] p < 0 .0001). Factors specifically associated with major complications in obese patients included COPD (OR 1.75 [1.55-2.00] p < 0.0001) and diabetes (OR 1.10 [1.02-1.1] p = 0.017). Hypertension (OR 1.12 [1.03-1.21] p = 0.0079) was associated with minor complications. Similarly, in patients with MetS, major complications were associated with COPD (OR 1.72 [1.35-2.18] p < 0.0001). Neuraxial anesthesia was associated with a lower risk for major complications in the obese cohort (OR 0.87 [0.81-0.92] p < 0.0001). BMI ≥ 40 was associated with a greater risk for minor complications (OR 1.37 [1.26-1.50] p < 0.0001), major complications (1.11 [1.02-1.21] p = 0.015), and increased LOS (+0.08 days [0.07-0.09] p < 0.0001).

Mean BMI in patients undergoing primary TKA increased from 2006 - 2017. MetS comorbidities such as diabetes and hypertension elevated the risk for complications in obese patients. COPD contributed to higher rates of major complications. The obesity-specific risk reduction with spinal anesthesia suggests an improved post-anesthetic clinical course in obese patients with pre-existing pulmonary pathology. Encouragingly, the overall rates of complications and LOS in patients with obesity and MetS exhibited a longitudinal decline. This finding may be related to the decreased proportion of patients with BMI ≥ 40 treated over the same period, possibly the result of quality improvement initiatives aimed at delaying high-risk surgery in morbidly obese patients until healthy weight loss is achieved. These findings may also reflect increased awareness and improved management of these patients and their elevated risk profiles.

Introduction. Recently, tibial insert design of cruciate-substituting (CS) polyethylene insert is employed. However, in vivo kinematics of using CS polyethylene insert is still unclear. In this study, it is hypothesized that CS polyethylene insert leads to stability of femolo-tibial joint as well as posterior-stabilized polyethylene insert, even if posterior cruciate ligament (PCL) is sacrificed after total knee arthroplasty (TKA). The purpose of this study is an investigation of in vivo kinematics of three different tibial insert designs using computer assisted navigation system intra-operatively in TKA. Materials and Methods. Sixty-four consecutive patients who had knees of osteoarthritis with varus deformity were investigated in this study. All TKAs (Triathlon, Stryker, New Jersey, USA) were performed using computer assisted navigation system. During surgery, three different designs of polyethylene tibial trial inserts (PS, CS, and cruciate-retaining (CR) polyethylene insert) were inserted respectively after implantation of femoral and tibial components. The kinematic parameters of the soft-tissue balance were obtained by interpreting kinematics curve, which display bicompartmental gaps throughout the range of motion (ROM) after implantation of each trial insert (Figure. 1). During record of kinematics, the surgeon gently lifted the experimental thigh three times, flexing the hip and knee. Deviation of these three values in each ROM was calculated in each tibial insert in each patient for descriptive analysis. Results. Regarding to values of compartmental gaps, there are no significance between three inserts in both medial and lateral compartments (Figure 2a, b). On medial compartmental gaps, the values of deviations were significantly higher in CR insert than both of PS and CS insert in ROM of over 45 degrees in extension (Fig 3a). In addition, concerning lateral compartmental gaps, the values of deviations were significantly higher in CS insert than both PS and CS insert in all ROM (Fig 3b). Furthermore, there was no significance between PS and CS insert in overall range of motion in both medial and lateral compartmental gaps (Fig 3a, b). Discussion. These results demonstrated that CS polyethylene insert has a stability of femoro-tibial joint nearly as well as PS polyethylene insert. While PS insert may leads to surface damage on open box and has necessity of cutting more bone of femur, some problems involving management of PCL are enumerated in CR inserts. The main design feature of Triathlon CS insert is single radius and rotary arc, in addition, the posterior lip is same as that of Triathlon CR, which can be the factor to avoid paradoxical anterior movement and to permit internal and external rotation between femoral and tibial component. Due to the design features and benefits, there is a high possibility that CS insert can lead same ROM as PS insert, although PS design can produce more ROM than the other type of insert type. Based on these backgrounds, it is suggested that CS insert may have an additional choice in TKA with some advantages especially in concerning of high activity patients like middle aged patients

Today TKA belongs to a standard care in orthopaedics and traumatology. The number of the annual implantations has clearly increased during the last years and also in the future an increasing rate to be expected.

Also the number of Revision TKA and the treatment of complicated pathologies in the primary care will increase in the same way.

Therefore the requirements of the surgeon rised as well as a suitable and accurate systems will be needed. Beside revision cases, traumatic-, post-traumatic- and RA-patients demonstrate partly distinctive bone and ligamentous pathologies.

Beside the primary implant components and instrumentation-systems, modern knee systems must include also modular revision systems compatible with the primary systems to be able to carry out complicated primary as well as light to moderately severe recision cases. Besides, also the possibility should be able to change within the system (with constant bone-cuttings) on higher degrees of the constrain.

With the TC-Primary and TC-Revision system fulfils the above mentioned criteria so that nearly every situation can be handled.

We present our experience using this system in cases of revisions, traumatic, post-traumatic and RA-cases The handling of bone and ligamentous defects will be demonstrated. In particular the possibility the use of the TC-Revision also in primary TKA as P a so named “extension primary system” will be emphasized.

By the Modulary and compatibility of the TC-Primary and TC-Revision systems, the use of Wedges and Stems as well as the possibility of the different degrees of the constrain a knee family permits us to treat complicated primary as well as mild to moderate revision cases.

Introduction

Schatzker V & VI tibial plateau fractures are serious life-changing injuries often resulting in significant complications including post-traumatic arthritis. Reported incidence of secondary TKA following ORIF of all tibial plateau fractures is 7.3% and 13% for Schatzker V & VI tibial. This study reports a 15-year single centre experience of CEF of Schatzker V & VI fractures including PROMs and incidence of secondary TKA. This study was approved by the local Institutional board.

Summary:

Smaller increments in the antero-posterior dimensions of femoral components allows significant improvements in balancing of the knee after TKA with restoration of more normal soft-tissue stability.

Background

The accurate positioning of the total knee arthroplasty affects the survival of the implants(1). Alignment of the femoral component in relation to the native knee is best determined using pre- and post-operative 3D-CT reconstruction(2). Currently, the scans are visualised on separate displays. There is a high inter- and intra-observer variability in measurements of implant rotation and translation(3). Correct alignment is required to allow a direct comparison of the pre- and post-operative surfaces. This is prevented by the presence of the prostheses, the bone shape alteration around the implant, associated metal artefacts, and possibly a segmentation noise.

Introduction:

Contemporary Posterior Cruciate Ligament (PCL) retaining TKA implants (CR) are associated with well-known kinematic deficits, such as absence of medial pivot motion, paradoxical anterior femoral sliding, and posterior femoral subluxation at full extension. The hypothesis of this study was that a biomimetic implant, reverse engineered by using healthy knee kinematics to carve the tibial articular surface, could restore normal kinematic patterns of the knee.

Introduction & Aims

Mild to moderate CD after TKA is a common side-effect of an otherwise successful procedure. Despite improvement in the majority of the cases within weeks to a few months, this is a source of concern and disappointment. This analysis presents a possible mechanism for post-TKA cognitive changes.

Patient reported outcome measures (PROMs) after total knee arthroplasty (TKA) are typically used to assess longitudinal change in pain and function after total knee arthroplasty (TKA). The Patient's Knee Implant Performance (PKIP) score was developed to evaluate outcomes more broadly including function, stability, confidence, and satisfaction. Although validated in patients having a primary TKA, the PKIP has not been evaluated as an outcome measure for patients having revision TKA. This study examined patient outcomes at one year following primary and revision TKA measured using the PKIP, compared to Oxford Knee Scores. A retrospective analysis of pre-operative and one-year post-operative outcomes was completed for 39 patients (21 female) who had primary (n=27) or revision (n=12) TKA with a single surgeon between 2017 and 2020. The mean age was 69.2±7.4 years, and mean weight 87.4± 5.1kg. The change over time and correlation between the self-reported outcome measures was evaluated. There was a significant improvement in the PKIP overall score at the 12-month follow-up (32± 13 v 69± 15, p= <0.001), with no significant difference between groups (3.3 points, p=0.50). Among the PKIP sub-scores, there was a significant improvement in knee confidence (3.5±2 vs 7.7±2; p<0.001), stability (3.4±2 vs 7.4±3; p<0.001) and satisfaction (2.5±1.7 vs 6.6±3, p<0.001). Between group differences in PKIP sub-scores one year after surgery were small and non-significant. For all patients, the OKS and PKIP scores were moderately correlated before surgery (r=0.64, p=<0.05), and at 1 year after surgery (r=0.61, p= <0.001). Significant improvements in knee confidence, stability, and satisfaction one year after TKA were identified from the PKIP responses, with no significant difference between primary and revision surgery. The moderate correlation with the OKS suggests these questionnaires measure difference constructs and may provide complementary outcome information in this patient cohort

Total Knee Arthroplasty (TKA) is a successful treatment for end stage osteoarthritis of the knee joint. However, post-operative pain can lead to patient dissatisfaction and poorer outcomes. Cooled radiofrequency nerve ablation (CRNA) has reportedly been effective at treating pain osteoarthritic knee pain by targeting the periarticular nerves of the knee. We undertook a prospective, controlled pilot study to determine if CRNA provides effective post-operative analgesia when utilised intra-operatively during total knee arthroplasty. Participants were recruited from January 2019 to February 2020. Those meeting inclusion criteria underwent TKA with intraoperative CRNA to 6 target sites prior to the cementing of implants. The primary outcomes were pain scores and opiate usage in the first 4 days post-operatively, then weekly up to 6 weeks. A total of 62 patients were screened and allocated sequentially; 18 were recruited to the control group and 12 recruited to the study group. The two groups did not have any significant difference in demographics. There were no clinically significant differences between the two groups in terms of pain scores nor opiate usage. There were complications as a result of the intervention. This study demonstrated no benefit of using intraoperative CRNA for improving post-operative pain scores or reducing opiate use after TKA

Demand for total knee arthroplasty (TKA) is increasing as it remains the gold-standard treatment for end-stage osteoarthritis (OA) of the knee. While magnetic-resonance imaging (MRI) scans of the knee are not indicated for diagnosing knee OA, they are commonly ordered prior to the referral to an orthopaedic surgeon. The purpose of this study was to determine the proportion of patients who underwent an MRI in the two years prior to their primary TKA for OA. Secondary outcomes included determining patient and physician associations with increased MRI usage. This is a population-based cohort study using billing codes in Ontario, Canada. All patients over 40 years-old who underwent a primary TKA between April 1, 2008 and March 31, 2017 were included. Statistical analyses were performed using SAS and included the Cochran-Armitage test for trend of MRI prior to surgery, and predictive multivariable regression model. Significance was set to p<0.05. There were 172,689 eligible first-time TKA recipients, of which 34,140 (19.8%) received an MRI in the two years prior to their surgery. The majority of these (70.8%) were ordered by primary care physicians, followed by orthopaedic surgeons (22.5%). Patients who received an MRI were younger and had fewer comorbidities than patients who did not (p<0.001). MRI use prior to TKA increased from 15.9% in 2008 to 20.1% in 2017 (p<0.0001). Despite MRIs rarely being indicated for the work-up of knee OA, nearly one in five patients have an MRI in the two years prior to their TKA. Reducing the use of this prior to TKA may help reduce wait-times for surgery

Deep infection is a devastating complication of total knee arthroplasty (TKA). This study aimed to determine if there was a relationship between surgeon volume and the incidence of revision for infection after primary TKA. Data from the Australian Orthopaedic Association National Joint Replacement Registry (AOANJRR) from 1 September 1999 to 31 December 2020 for primary TKA for osteoarthritis that were revised for infection. Surgeon volume was defined by the number of primary TKA procedures performed by the surgeon in the year the primary TKA was performed and grouped as <25, 25-49, 50-74, 75-99, >100 primary TKA procedures per year. Kaplan Meir estimates for cumulative percent revision (CPR) and Cox Proportional Hazard Ratios were performed to compare rates of revision for infection by surgeon volume, with sub-analyses for patella and polyethylene use, age <65 years and male gender. 5295 of 602,919 primary TKA for osteoarthritis were revised for infection. High volume surgeons (>100 TKA/year) had a significantly lower rate of revision for infection with a CPR at 1 and 17 years of 0.4% (95% CI 0.3, 0.4) and 1.5% (95% CI 1.2, 2.0), respectively, compared with 0.6% (95% CI 0.5, 0.7) and 2.1% (95% CI 1.8, 2.3), respectively, for low volume surgeons (<25 TKR/year). Differences between the high-volume group and the remaining groups remained when sub-analysis for age, gender, ASA, BMI, patella resurfacing and the use of cross-linked polyethylene (XLPE). High volume surgeons have lower rates of revision for infection in primary TKA

Aim. Periprosthetic joint infection (PJI) is one of the most frequent and devastating complications of total knee arthroplasty (TKA). Accurate diagnosis and proper treatment are essential to prevent functional loss and progression to systemic infection. However, the correct diagnosis of PJI is still a challenge since there is no accurate diagnostic method and the existing diagnostic criteria are based on serological, histological and microbiological tests that are imprecise and time-consuming. Recently, it was demonstrated that cell-free DNA is increased in the synovial fluid of patients with PJI. Therefore, this study aims to evaluate a new point-of-care methodology for quantifying free DNA in synovial fluid. Method. A prospective study was carried out with patients undergoing TKA revision surgery, from whom it was possible to collect synovial fluid (SF) during the surgical procedure. Cell-free DNA quantification was performed directly from the SF, using a portable fluorimeter. Sensitivity, specificity and receiver operating characteristic (ROC) curve were calculated. Results. Fifty-four patients were included in the study, of which 25 were diagnosed with PJI. Cell-free DNA levels measured immediately after collection were increased in the synovial fluid of patients with PJI (26.3 ± 14.8) in comparison with the uninfected group (4.6 ng/ml ± 3.8, p< 0.0001). The area under the receiver operating characteristic curve (AUC ROC) was 0.981 (95% CI 0.914 to 0.999). Conclusions. From the results presented, we can conclude that the quantification of free DNA with a portable fluorimeter proved to be a test with high sensitivity and specificity for the diagnosis of PJI

Ten to twenty percent of patients are dissatisfied with the clinical result after total knee arthroplasty (TKA). Aim of this study was to investigate the impact of personality traits on patient satisfaction and subjective outcome of TKA. We investigated 80 patients with 86 computer navigated TKAs (Emotion®, B Braun Aesculap) and asked for patient satisfaction. We divided patients into two groups (satisfied or dissatisfied). 12 personality traits were tested by an independent psychologist, using the Freiburg Personality Inventory (FPI-R). Postoperative examination included Knee Society Score (KSS), Western Ontario and McMaster University Osteoarthritis Index (WOMAC) and the Visual Analogue Scale (VAS). Radiologic investigation was done in all patients. 84% of our patients were satisfied, while 16% were not satisfied with clinical outcome. The FPI-R showed statistically significant influence of four personality traits on patient satisfaction: life satisfaction (ρ = 0.006), performance orientation (ρ =0.015), somatic distress (ρ = 0.001), and emotional stability (ρ = 0.002). All clinical scores (VAS, WOMAC, and KSS) showed significant better results in the satisfied patient group. Radiological examination showed optimal alignment of all TKAs. There were no complications requiring revision surgery in both groups. The results of our study show that personality traits may influence patient satisfaction and clinical outcome after TKA. Thus, patients personality traits may be a useful predictive factor for postoperative satisfaction after TKA

The purpose of this study was (1) to evaluate the adequacy of informed consent documentation in the trauma setting for distal radius fracture surgery compared with the elective setting for total knee arthroplasty (TKA) at a large public hospital and (2) to explore the relevant guidelines in New Zealand relating to consent documentation. Consecutive adult patients (≥16 years) undergoing operations for distal radius fractures and elective TKA over a 12-month period in a single-centre were retrospectively identified. All medical records were reviewed for the risks and complications recorded. The consent form was analysed using the Flesch Reading Ease Score (FRES) and the Simple Measure of Gobbledygook (SMOG) index readability scores. A total of 133 patients undergoing 134 operations for 135 distal radius fractures and 239 patients undergoing 247 TKA were included. Specific risks of surgery were recorded significantly less frequently for distal radius fractures than TKA (43.3% versus 78.5%, P < 0.001). Significantly fewer risks were recorded in the trauma setting compared to the elective (2.35 ± 2.98 versus 4.95 ± 3.33, P < 0.001). The readability of the consent form was 40.5 using the FRES and 10.9 using the SMOG index, indicating a university undergraduate level of reading. This study has shown poor compliance in documenting risks of surgery during the informed consent process in an acute trauma setting compared to elective arthroplasty. Institutions must prioritise improving documentation of informed consent for orthopaedic trauma patients to ensure a patient-centred approach to healthcare

The benefits of HXLPE in total knee arthroplasty (TKA) have not been as evident as total hip arthroplasty (THA). A systematic review and meta-analysis to assess the impact of highly-crosslinked polyethylene (HXLPE) on TKA outcomes compared to conventional polyethylene (CPE) is described. All studies comparing HXLPE with CPE for primary TKA were included for analysis. The minimum dataset included revision rates, indication for revision, aseptic component loosening and follow-up time. The primary outcome variables were all-cause revision, aseptic revision, revision for loosening, radiographic component loosening, osteolysis and incidence of radiolucent lines. Secondary outcome measures included postoperative functional knee scores. A random-effects meta-analysis allowing for all missing data was performed for all primary outcome variables. Six studies met the inclusion criteria. In total, there were 2,234 knees (1,105 HXLPE and 1,129 CPE). The combined mean follow-up for all studies was 6 years. The aseptic revision rate in the HXLPE group was 1.02% compared to 1.97% in the CPE group. There was no difference in the rate of all-cause revision (p = 0.131), aseptic revision (p = 0.298) or revision for component loosening (p = 0.206) between the two groups. Radiographic loosening (p = 0.200), radiolucent lines (p = 0.123) and osteolysis (p = 0.604) was similar between both groups. Functional outcomes were similar between groups. The use of HXLPE in TKA yields similar results for clinical and radiographic outcomes when compared to CPE at midterm follow-up. HXLPE does not confer the same advantages to TKA as seen in THA