OBJECTIVES. The use of a mobile bearing has been suggested to decrease the rate of patellar complications after total knee arthroplasty (TKA). However, to resurface or retain the native patella remains debated. Few long-term results have been documented. The present retrospective study was designed to evaluate the long-term (more than 10 years) results of mobile bearing TKAs on a national scale, and to compare pain results and survivorship according to the status of the patella. The primary hypothesis of this study was that the 10 year survival rate of mobile bearing TKAs with patella resurfacing will be different from that of mobile bearing TKAs with native patella retaining. METHODS. All patients operated on between 2001 and 2004 in all participating centers for implantation of a TKA (whatever design used) were eligible for this study. Usual demographic and peri-operative items have been recorded. All patients were contacted after the 10 year follow-up for repeat clinical examination (Knee Society score (KSS), Oxford knee questionnaire). Patients who did not return were interviewed by phone call. For patients lost of follow-up, family or general practitioner was contacted to obtain relevant information about prosthesis survival. TKAs with resurfaced patella and TKAs with retained native patella were paired according to age, gender, body mass index and severity of the coronal deformation (with steps of 5°). Pain score, KSS and Oxford knee score were compared between two groups with a Student t-test at a 0.05 level of significance. Survival curve was plotted according to the actuarial technique, using the revision for mechanical reason as end-point. The influence of the patella status was assessed with a logrank test at a 0.05 level of significance. RESULTS. 1,604 TKAs were implanted during the study time-frame. 849 cases could be paired according to age, gender, BMI and severity of the pre-operative coronal deformation (2/1 ratio) into two groups: resurfaced patella (496 cases) and retained patella (243 cases). There was no difference in any baseline criteria between both groups. 150 patients deceased before the 10 year follow up (18%). Final follow-up was obtained for 489 cases (58%). 31 reoperations (prosthesis exchange or patellofemoral revision) were performed during the study time frame (4%), with 17 reoperations for mechanical reasons (3%). KSS and Oxford knee score were significantly higher for TKAs without patella resurfacing, there was a significant difference between the 13 year survival rates of TKAs with resurfaced patella (97%) and TKAs with retained native patella (93%). CONCLUSIONS. The primary hypothesis was confirmed: 10 year survival rate of mobile bearing TKAs with patella resurfacing was better than mobile bearing TKAs with native patella retaining. Patella resurfacing may lead to a better survival after mobile bearing TKA. However, the clinical results were better after patella resurfacing when the index TKA was not revised

Introduction. Computed tomography (CT) based preoperative planning provides useful information for severe TKA and revision TKA cases, such as the amount of augmentation, length of stem extension and component alignment, to achieve correct alignment and joint line. In this study, we evaluated TKA alignment performed with CT preoperative planning. Materials and Methods. 7 primary TKAs for severe deformity and 3 revision TKAs were included. CT preoperative planning was performed with JIGEN (LEXI, Japan). Constrained condylar prosthesis (LCCK, Zimmer) were used in all case. For femoral component, axial alignment was decided by controlled IM rod insertion to femoral canal. Rotational alignment was decided according to anterior cortex that usually was not compromised. For tibial component, axial alignment was set to perpendicular to tibial mechanical axis. Coverage and joint line level were carefully decided. The amount of bone resection of bilateral distal and posterior femoral condyle and proximal tibia was measured, respectively. Stem extension length and offset were selected according to components position and canal filling. Amount of augmentation was also estimated bilateral distal and posterior femoral condyle, respectively. Postoperative component alignment was evaluated three-dimensionally with Knee-CAS (LEXI, Japan). Results. All femoral and tibial components were implanted within 5°in coronal and sagittal plane. All knees showed mechanical alignment within 5 degree from neutral. One of 10 TKAs needed femoral component size down, and two of 20 stems needed size change

The Columbus® knee system was designed as a standard knee implant that allows high flexion without the need for additional bone resection. The aim of this retrospective study was to investigate the correlation between the maximum flexion achieved at five years and the slope of the tibial component. The hypothesis was that increased slope would give increased flexion. The study design was a retrospective cohort study at a single centre. The inclusion criterion was having had a navigated cemented Columbus primary TKA implanted between March 2005 and December 2006 using the image free OrthoPilot® navigation system (Aesculap, Tuttlingen, Germany) in our institution. Follow-up had been carried out at review clinics by an independent arthroplasty team. Patient-related data had been recorded either in case notes, the departmental proprietary database or as radiographic images. In addition to demographics, five-year follow-up range of motion (ROM) was collected. All available radiographs on the national Picture Archiving and Communication System (Eastman Kodak Company, 10.1_SP1, 2006), whether taken at our institution or at the patient's local hospital, were analysed by a trainee orthopaedic surgeon (NCS) who was independent of the patients' care. Component position according to the Knee Society TKA scoring system was determined from the five-year review lateral x-ray. The tibial slope was calculated as 90° minus the angle of the tibial component so giving a posterior slope as a positive number and an anterior slope as a negative number. The correlation between maximum flexion angle and tibial slope was calculated. Further to this a subgroup of only CR prostheses and patients with BMI <35 were analysed for a relationship. The tibial slope of the group of patients having 90° or less of flexion (poor flexion) was compared to those having 110° or more (good flexion) using a t-test, as was the flexion of the those with BMI <30 to those with BMI > 35. A total of 219 knees in 205 patients were identified. 123 had five-year radiograph and maximum flexion measurement available. Cohort demographics were mean age 68(8.6), mean BMI 32.0(5.9) and mean maximum flexion at five years of 101°(11°). The tibial slope angle showed variation around the mean of 2°(2.8°). There was no correlation between tibial slope and maximum flexion for either that whole cohort (r=-0.051, p=0.572, Figure 1b) or the subgroup of CR and BMI <35 patients (n=78, r = −0.089, p=0.438). The mean tibial slope of those patients having poor flexion was 2° (SD2.6°) and this was not significantly different to the mean for those with good flexion, 3° (SD3.1°) p=0.614. The mean flexion of those with BMI <30 was 100° (SD8.7°) and this was not significantly different to those with BMI >35, mean 101° (SD11.4°). This study did not find any correlation between the tibial slope and maximum flexion angle in 123 TKAs at five year follow up. Further studies with a more accurate measurement of tibial slope should be carried out to confirm whether a relationship exists in the clinical setting

Aim

To assess the outcome and complication rate of rotating hinge knee prostheses in our unit.

Aim. Antimicrobial resistance (AMR) aggravates an already difficult treatment of periprosthetic joint infections (PJI). The prevalence of drug-resistant pathogens varies across countries and increases over time. Regular monitoring of bacteriological analyses should be performed. Due to many factors influencing the AMR, the correct choice of antimicrobial management remains arguable. The primary purpose of this retrospective study was to identify and compare causative bacteria and to compare the incidence of antibiotic resistance between the septic revision total knee arthroplasty (TKA) and septic revision total hip arthroplasty (THA). Method. A review of all revision TKAs and revision THAs, undertaken between 2007 and 2020 in a tertiary referral centre, was performed. Included were cases meeting the consensus criteria for PJI, in which an organism has been identified. There were no major differences in tissue sampling between revision TKAs and revision THAs over time. Results. A total of 228 bacterial strains, isolated after revision TKA and THA, were analysed for their resistance to 20 different antibiotics. There was a statistically significant higher occurrence of Gram-negative bacteria (p=0.002) and Enterococcus species (p=0.026) identified after revision THAs compared to TKA. The comparison of antibiotic resistance between revision TKAs and revision THAs was statistically significant in 9 of 20 analysed antibiotics. Pathogens isolated after revision THA were much more resistant compared to pathogens isolated after revision TKA. Resistance in revision THAs was significantly higher to oxacillin (p=0.03), ciprofloxacin (p<0.001), levofloxacin (p<0.001), moxifloxacin (p=0.005), clindamycin (p<0.001), co-trimoxazole (p<0.001), imipenem (p=0.01), rifampicin (p=0.005) and tetracycline (p=0.009). There was no significantly higher resistance of pathogens isolated after revision TKAs detected. No statistically significant difference in antibiotic resistance of Gram-negative bacteria between revision TKA and revision THA was observed. Conclusions. The occurrence and the resistance of bacteria to antibiotics differs significantly between revision TKAs and revision THAs. This has implications on of the choice of empirical antibiotic in revision surgery as well as prophylactic antibiotic in primary surgery, depending on the joint that is to be replaced

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 New Zealand Joint Registry (NZJR) was established in 1999. However, ethnicity data was not recorded by prioritisation in line with Ministry of Health (MoH) recommendations. Recently, cross-referencing with MoH updated ethnicity data for all 326,150 entries in the NZJR database. The objective of this national level, population study was to identify any ethnic disparities in access and outcome for Māori for primary total hip (THA) and knee arthroplasty (TKA) for Osteoarthritis. The utilisation rate for THA and TKAs were calculated for the Māori and NZ European population from all data in the NZJR and Census data in 2001, 2006, 2013 and 2018. Utilisation rate was reported separately for four age groups (<55, 55-64, 65-74, >75) over four time periods (1999-2004, 2005-2009, 2010-2014, 2015-2020). Revision rate, 6 months and 5-year Oxford scores were adjusted for age, sex and BMI, then compared between groups. In every age group and at all but one time point, significant under-utilisation of TKA was observed in Māori. For THAs, Māori had similar utilisation rates in the <55 and 55-64 age groups, but significantly lower utilisation rates in all other age groups. When adjusted for age, sex and BMI, no significant differences in revision rates were observed between Māori and NZ Europeans for THAs (HR 0.939, P 0.417) or TKAs (HR 1.129, P 0.149). Adjusted 6 months and 5-year Oxford scores were significantly higher in NZ Europeans, however, the maximum difference was less than 3 points and is unlikely to be clinically significant. Despite the same risk of being diagnosed with osteoarthritis, Māori are less likely to undergo THA and TKA. There are no clinically significant differences in outcomes post arthroplasty between Māori and NZ Europeans. Further research is required to investigate causes for lower utilisation in Māori

This study aimed to analyze the effect of two different techniques of cement application: cement on bone surface (CoB) versus cement on bone surface and implant surface (CoBaI) on the short-term effect of radiolucent lines (RLL) in primary fully cemented total knee arthroplasties (TKA) with patella resurfacing. 379 fully cemented TKAs (318 patients) were included in this monocentric study. Preoperative and postoperative at week 4 and 12 month after surgery all patients had a clinical and radiological examination and were administered the Oxford Knee Score (OKS). Cement was applied in two different ways among the two study groups: cement on bone surface (CoB group) or cement on bone surface and implant surface (CoBaI group). The evaluation of the presence of RLL or osteolysis was done as previously described using the updated Knee Society Radiographic Evaluation System. The mean OKS and range of motion improved significantly in both groups at the 4-week and 12-month follow-up, with no significant difference between the groups (CoB vs. CoBaI). RLL were present in 4.7% in the whole study population and were significantly higher in the CoBaI group (10.5%) at the 4-week follow-up. At the 12-month follow-up RLL were seen in 29.8% of the TKAs in the CoBaI group, whereas the incidence was lower in the CoB group (24.0% (n.s.)). There were two revisions in each group. None of these due to aseptic loosening. Our study indicated that the application of bone cement on bone surface only might be more beneficial than onto the bone surface and onto the implant surface as well in respect to the short-term presence of RLL in fully cemented primary TKA. The long-term results will be of interest, especially in respect to aseptic loosening and might guide future directions of bone cement applications in TKA

The introduction of robotics for total knee arthroplasty (TKA) into the operating theatre is often associated with a learning curve and is potentially associated with additional complications. The purpose of this study was to determine the learning curve of robotic-assisted (RA) TKA within a multi-surgeon team. This prospective cohort study included 83 consecutive conventional jig-based TKAs compared with 53 RA TKAs using the Robotic Surgical Assistant (ROSA) system (Zimmer Biomet, Warsaw, Indiana, USA) for knee osteoarthritis performed by three high-volume (> 100 TKA per year) orthopaedic surgeons. Baseline characteristics including age, BMI, sex and pre-operative Kellgren-Lawrence grade were well-matched between the conventional and RA TKA groups. Cumulative summation (CUSUM) analysis was used to assess learning curves for operative times for each surgeon. Peri-operative and delayed complications were reviewed. The CUSUM analysis for operative time demonstrated an inflexion point after 5, 6 and 15 cases for each of the three surgeons, or 8.7 cases on average. There were no significant differences (p = 0.53) in operative times between the RA TKA learning (before inflexion point) and proficiency (after inflexion point) phases. Similarly, the operative times of the RA TKA group did not differ significantly (p = 0.92) from the conventional TKA group. There was no discernible learning curve for the accuracy of component planning using the RA TKA system. The average length of post-operative follow-up was 21.3 ± 9.0 months. There was no significant difference (p > 0.99) in post-operative complication rates between the groups. The introduction of the RA TKA system was associated with a learning curve for operative time of 8.7 cases. Operative times between the RA TKA and conventional TKA group were similar. The short learning curve implies this RA TKA system can be adopted relatively quickly into a surgical team with minimal risks to patients

The optimal timing of when to perform manipulation under anesthesia (MUA) for stiffness following total knee arthroplasty (TKA) is unclear. This study aimed to identify the risk factors for MUA following primary TKA and whether performing an “early” MUA within 3 months results in a greater improvement in range of motion. Primary TKAs performed between January 2013 and December 2018 at three tertiary New Zealand hospitals were reviewed. International Classification of Diseases discharge coding was used to identify patients who underwent an MUA. Multivariate Cox regression was performed to identify patient and surgical risk factors for MUA. Pre- and post-MUA knee flexion angles were identified through manual review of operation notes. Multivariate linear regression was performed to compare the mean flexion angles pre- and post-MUA, as well as the mean gain in flexion, between patients undergoing “early” (<3 months) versus “late” MUA (>3 months). 7386 primary TKAs were analyzed in which 131 underwent subsequent MUA (1.8%). Patients aged <65 years were two times more likely to undergo MUA compared to patients aged ≥65 years (2.5% versus 1.3%, adjusted hazard ratio = 2.1, p<0.001). Gender, body mass index, patient comorbidities or a history of cancer were not associated with the risk of MUA. There was no difference in the final post-MUA flexion angle between patients who underwent early versus late MUA (104.7 versus 104.1 degrees, p = 0.819). However, patients who underwent early MUA had poorer pre-MUA flexion (72.3 versus 79.6 degrees, p = 0.012), and subsequently had a greater overall gain in flexion compared to patients who underwent late MUA (mean gain 33.1 versus 24.3 degrees, p<0.001). Younger age was the only patient risk factor for MUA. A greater overall gain in flexion was achieved in patients who underwent early MUA within 3 months

Background. While posterior cruciate retaining (PCR) implants are a more common total knee arthroplasty (TKA) design, newer bi-cruciate retaining (BCR) TKAs are now being considered as an option for many patients, especially those that are younger. While PCR TKAs remove the ACL, the BCR TKA designs keep both cruciate ligaments intact, as it is believed that the resection of the ACL greatly affects the overall kinematic patterns of TKA designs. Various fluoroscopic studies have focused on determination of kinematics but haven't defined differentiators that affect motion patterns. This research study assesses the importance of the cruciate ligaments and femoral geometry for Bi-Cruciate Retaining (BCR) and Posterior Cruciate Retaining (PCR) TKAs having the same femoral component, compared to the normal knee. Methods. The in vivo 3D kinematics were determined for 40 subjects having a PCR TKA, 10 having a BCR TKA, and 10 having a normal knee, in a retrospective study. All TKA subjects had the same femoral component. All subjects performed a deep knee bend under fluoroscopic surveillance. The kinematics were determined during early flexion (ACL dominant), mid flexion (ACL/PCL transition) and deep flexion (PCL dominant). Results. During the first 30 degrees of flexion, the ACL played an important role, as subjects having a BCR TKA experienced kinematic patterns more similar to the normal knee. During mid flexion, both TKAs experienced random kinematic patterns, which could be due to the ACL and PCL being less active or resected in PCR TKA. In deeper flexion, both TKAs experienced kinematic patterns similar to the normal knee, thus supporting the assumption that the PCL played a dominant role [Fig. 1, Fig. 2]. All three groups generally experienced progressive axial rotation throughout flexion [Fig. 3]. On average, subjects having a PCR TKA experienced 112.3° of flexion, which was greater than the BCR subjects. Conclusions. Both the BCR TKA and normal groups experienced similar kinematic patterns, but the femoral geometrical differences from the anatomical condition may have influenced decreased motion compared to the normal knee. Both TKAs experienced similar kinematic patterns in deeper flexion, with the PCR TKA experiencing excellent weight-bearing flexion. Results from this study suggest that the cruciate ligaments can play a role in kinematics, but femoral geometry working with the ligaments may be an option to consider

Background/Introduction. As a new generation of robotic systems is introduced into the world of arthroplasty, Robotic-Assisted Total Knee Arthroplasty (TKA) represents a growing proportion of a reconstructive surgeon's operative volume. This study aims to compare the post-operative readmission rate, pain scores, costs, as well as the effects on surgeon efficiency one year after adoption of these technologies into clinical practice. Methods. A retrospective chart review was conducted regarding all conventional and robotic-assisted TKAs performed by a single surgeon in the year following January 1, 2017, the date MAKO Robotic-Assisted TKAs were introduced at our intuition. All patients over age 18 with a diagnosis of primary osteoarthritis of the knee who underwent TKA during this period were identified. Records were analyzed for differences in readmission, pain scores, tourniquet time, and operating room charges. Results. A total of 208 patients met inclusion criteria and were included in this analysis (97 Robotic-Assisted TKAs & 111 conventional TKAs). Robotic-Assisted TKAs incurred a mean total OR cost of $44,785 in the first quarter of implementation. This decreased to $43,124 over the subsequent year. Conventional TKAs incurred a mean total OR cost of $41,277. Among Robotic-Assisted TKAs, the mean tourniquet time was 70 minutes in the first month the technology was implemented. Mean tourniquet time for conventional TKAs was 42 minutes. Over time, variance in tourniquet times decreased substantially and tourniquet time for Robotic-Assisted TKAs trended towards being time neutral (49 minutes) (P=0.001). More importantly, in this study Robotic-Assisted TKAs were readmitted at a rate of only 1% (1/97). This represents a substantial reduction in readmission when compared to conventional TKAs, which were readmitted at a rate of 4.5% (5/111) (P=0.13). Interestingly, Robotic-Assisted TKAs averaged lower pain scores (2.9) compared to conventional TKAs (3.2), a finding that trended towards significance (P=0.13). Discussion/Conclusions. Implementation of Robotic-Assisted TKA resulted in an initial increase in mean OR cost and tourniquet time. Although there is a learning curve with specific regard to surgeon efficiency, there was no increase in the rate of complications and the trend in tourniquet time approached being time neutral one year after implementation. Though Robotic-Assisted TKAs continue to represent an increased cost burden compared to conventional TKAs, this may be offset by lower pain scores and more importantly a substantial reduction in post-operative readmission. Since readmissions represent a relatively rare occurrence following TKA, further large-scale studies are required to validate this preliminary data

Until recently, research has failed to show a difference between posterior-stabilised (PS) and cruciate-retaining (CR) designs in total knee arthroplasty (TKA). This classic debate has been given pause over the past decade due to futile efforts to prove one design superior over the other. Recently, anterior-lipped and more conforming CR bearings have emerged to substitute for the PCL, if absent, damaged or resected, and obviate the need for the archaic cam-post mechanism of a traditional PS design. Advantages of avoiding a PS TKA include decreasing the risk of femoral condylar fracture that may occur via the box cut, as well as decreasing operative time by removing that step in the procedure. Avoiding a post-cam mechanism also removes the articulation that is a source of wear, post deformation, breakage, or dislocation. Patella clunk is also associated solely with PS designs. Modern anterior lipped inserts in PCL-deficient TKAs have demonstrated similar functional outcomes compared to PS knees. A prospective randomised controlled trial of 28 patients undergoing bilateral TKAs had a PS bearing in one knee and a contralateral CS insert with the PCL excised and reported no functional outcome difference at 5-year follow up. Scott and co-authors compared 56 PS TKAs to 55 TKAs with anterior-lipped inserts in a randomised, prospective study and found no functional outcome differences at minimum two-year follow up, with tourniquet times significantly longer in the PS group. In a recent report, 43 anterior-lipped compared to 39 matched PS TKAs had equivalent function scores at minimum 1-year follow-up. Ultra-congruent bearings provide inherent stability in TKA and two studies have reported identical functional outcomes compared to PS TKAs. Finally, there is now recent registry data that demonstrates a significant decrease in long-term survivorship in PS TKAs with a 45% higher risk of revision compared to minimally stabilised bearings in TKA. Equivalent functional outcomes in multiple studies comparing CR-type bearings and PS TKAs, combined with the potential deleterious outcomes associated with PS designs and increased risk of revision and decreased long-term survivorship, preclude the need for PS TKA designs in the modern healthcare environment. Hence, PS TKA designs are truly “vestigial organs”, and should be relegated to historical interest

This study aimed to evaluate the month-to-month prevalence of antibiotic dispensation in the 12 months before and after total knee arthroplasty (TKA) and total hip arthroplasty (THA) and to identify factors associated with antibiotic dispensation in the month immediately following the surgical procedure. In total, 4,115 THAs and TKAs performed between April 2013 and June 2019 from a state-wide arthroplasty referral centre were analysed. A cross-sectional study used data from an institutional arthroplasty registry, which was linked probabilistically to administrative dispensing data from the Australian Pharmaceutical Benefits Scheme. Multivariable logistic regression was carried out to identify patient and surgical risk factors for oral antibiotic dispensation. Oral antibiotics were dispensed in 18.3% of patients following primary TKA and 12.0% of patients following THA in the 30 days following discharge. During the year after discharge, 66.7% of TKA patients and 58.2% of THA patients were dispensed an antibiotic at some point. Patients with poor preoperative health status were more likely to have antibiotics dispensed in the month following THA or TKA. Older age, undergoing TKA rather than THA, obesity, inflammatory arthritis, and experiencing an in-hospital wound-related or other infectious complications were associated with increased antibiotic dispensation in the 30 days following discharge. A high rate of antibiotic dispensation in the 30 days following THA and TKA has been observed. Although resource constraints may limit routine wound review for all patients by a surgeon, a select cohort may benefit from timely specialist review postoperatively. Several risk factors identified in this study may aid in identifying appropriate candidates for such changes to follow-up care

Background. As life expectancy increases, the number of octogenarians requiring primary and revision total knee arthroplasty (TKA) is increasing. Recently, primary TKA has become a common treatment option in octogenarians. However, surgeons are still hesitant about performing revision TKA on octogenarians because of concerning about risk- and cost-benefit. The purpose of this study was to investigate postoperative complications and mid-term survival in octogenarians following primary and revision total knee arthroplasty (TKA). Methods. We retrospectively reviewed 231 primary TKAs and 41 revision TKAs performed on octogenarians between 2000 and 2016. The mean age was 81.9 for primary TKA and 82.3 for revision TKA (p=0.310). The American Society of Anesthesiologists (ASA) score was not different, but the age-adjusted Charlson comorbidity index was higher in revision TKA (4.4 vs. 4.8, p=0.003). The mean follow-up period did not differ (3.8 vs. 3.5 years, p=0.451). The WOMAC scores and range of motion (ROM) were evaluated. The incidence of postoperative complication and survival rate (end point; death determined by telephone or mail communication with patient or family) were investigated. Results. The postoperative WOMAC and ROM were better in primary TKA (33.1 vs. 47.2, p<0.001; 128.9° vs. 113.6°, p<0.001). The most common postoperative complication was delirium in both groups (7.4% vs. 14.6%, p=0.131). There were no differences in the specific complication rates between the two groups. The 5- and 10-year survival rates were 87.2% and 62.9%, respectively, in primary TKA and 82.1% and 42.2%, respectively, in revision TKA (p=0.017). Conclusions. Both primary and revision TKAs are viable options for octogenarians when considering the clinical results and mid-term survival. Delirium needs to be managed appropriately as the most common complication in both primary and revision TKAs for octogenarians

Introduction/Aim. Outcomes for guided motion primary total knee arthroplasty (TKA) in obese patients are unknown. Materials and Methods. 1,684 consecutive patients underwent 2,059 primary TKAs with a second-generation guided motion implant (Journey II Bi-Cruciate Stabilized Knee System, Smith & Nephew, Inc., Memphis) between 2011–2017 at three European and seven US sites. Results. Of 2,003 (97.3%) TKAs in 1,644 patients with BMI data: average age 64.5 years; 58.4% females; average BMI 32.5 kg/m. 2. ;13.4% had BMI ≥ 40 kg/m. 2. Subjects with BMI ≥ 40 kg/m. 2. had longest length of hospital stay (LOS) at European sites; LOS similar at US sites. Subjects with BMI ≥ 40 kg/m. 2. (P=0.0349) had longest surgery duration. BMI ≥ 40 kg/m. 2. had more re-hospitalizations or post-TKA reoperations than BMI < 40 kg/m. 2. (12.7% and 9.2% at five-year post-TKA, P<.0495). 62 TKAs were revised (3.39/100 TKA at five years) with no differences in revision risk between groups. 17 (27.4%) revisions involved femoral or tibial component removal; 45 (72.6%) involved tibial insert or patellar component removal only with revision risk similar between groups. Discussion. Our results corroborate literature-reported revision outcomes of standard TKAs in obese patients. Conclusion. Surgery duration and long-term complication rates are higher in patients with BMI ≥ 40 kg/m. 2. , but device revision risk is not elevated

Background. The knowledge about the common mode of failure and each period in primary and revision TKAs offers useful information to prevent those kinds of failure in each surgery. However, there has been limited report that simultaneously compared the mode of failure between primary and revision TKAs using single prosthesis. We compared the survival rate, mode of failure, and periods of each mode of failure between primary and revision TKAs. Methods. A consecutive cohort of 1606 knees (1174 patients) of primary TKA and 258 knees (224 patients) of revision TKA using P.F.C® prosthesis was retrospectively reviewed. The mean follow-up periods of primary and revision TKAs were 10.2 and 10.8 years, respectively. We compared the above variables between primary and revision TKAs. Results. The average 5-, 10-, 15-year survivor rate of primary TKA were 99.1% (CI 95%, ±0.3%), 96.7% (CI 95%, ±0.7%), and 85.4% (CI 95%, ±2.0%). They were 97.8% (CI 95%, ±1.0%), 91.4% (CI 95%, ±2.5%), and 80.5% (CI 95%, ±4.5%) in revision TKA. The common mode of failure included polyethylene wear, loosening, and infection in both primary and revision TKAs. The most common mode of failure was polyethylene wear in primary TKAs and infection in revision TKAs. The mean periods of polyethylene wear and loosening were not significantly different between primary and revision TKAs, but the mean period of infection was significantly long in revision TKA (4.8 years vs. 1.2 years, p=0.003). Conclusions. The survival rate decreased with time, especially after 10 years in both primary and revision TKAs. The continuous efforts are required to prevent and detect various modes of failure during the long-term follow-up after primary and revision TKAs. More careful attention is necessary to detect the late infection as a mode of failure after revision TKA. Level of Evidence. Level III, Therapeutic study. See the Guidelines for Authors for a complete description of levels of evidence

Introduction. The mobile-bearing (MB) total knee arthroplasty (TKA) design was introduced with the aim of reducing polyethylene wear and component loosening seen in the fixed-bearing (FB) design. A recent joint registry study has revealed increased risk for all-cause revision, but not revision for infection, in MB-TKA. We used the New Zealand Joint Registry (NZJR) to compare all-cause revision rates, and revision rates for aseptic loosening of MB-TKA compared with fixed bearing (FB) TKA. Methods. All patients who underwent a primary TKA registered in the NZJR between the 1st January 1999 to 31st December 2021 were identified. Analysis compared MB to FB designs, with sub analysis of implants from a single company. We identified 135,707 primary TKAs, with 104,074 (76.7%) FB-TKAs and 31,633 (23.3%) MB-TKAs recorded. We examined all-cause revision rates, reasons for revision and performed survival analyses. Results. For all-comers, MB-TKA had an all-cause revision rate of 0.43/100-component-years (OCY) compared with 0.42/OCY for FB-TKA (p=0.09). The all-cause revision rate was higher for those age < 65 years (MB TKA 0.60/OCY vs. FB-TKA 0.59/OCY) compared to those > 65 years at time of primary TKA (MB-TKA 0.29/OCY vs. FB-TKA 0.32/OCY), however there was no statistically significant difference between implant design in either age group (p=0.16 and p=0.64; respectively). Similarly, there was no difference in revision rates for aseptic loosening between implant designs. Kaplan-Meier survival analysis demonstrates no statistically significant difference in revision-free survival of implants, with both MB-TKA and FB-TKA demonstrating ∼93% revision free survival at 23 years. Conclusions. Both FB- and MB-TKA demonstrated excellent survivorship, with no significant difference in all-cause revision rates or revision for aseptic loosening between implant designs

Approximately 20% of patients feel unsatisfied 12 months after primary total knee arthroplasty (TKA). Current predictive tools for TKA focus on the clinician as the intended user rather than the patient. The aim of this study is to develop a tool that can be used by patients without clinician assistance, to predict health-related quality of life (HRQoL) outcomes 12 months after total knee arthroplasty (TKA). All patients with primary TKAs for osteoarthritis between 2012 and 2019 at a tertiary institutional registry were analysed. The predictive outcome was improvement in Veterans-RAND 12 utility score at 12 months after surgery. Potential predictors included patient demographics, co-morbidities, and patient reported outcome scores at baseline. Logistic regression and three machine learning algorithms were used. Models were evaluated using both discrimination and calibration metrics. Predictive outcomes were categorised into deciles from 1 being the least likely to improve to 10 being the most likely to improve. 3703 eligible patients were included in the analysis. The logistic regression model performed the best in out-of-sample evaluation for both discrimination (AUC = 0.712) and calibration (gradient = 1.176, intercept = -0.116, Brier score = 0.201) metrics. Machine learning algorithms were not superior to logistic regression in any performance metric. Patients in the lowest decile (1) had a 29% probability for improvement and patients in the highest decile (10) had an 86% probability for improvement. Logistic regression outperformed machine learning algorithms in this study. The final model performed well enough with calibration metrics to accurately predict improvement after TKA using deciles. An ongoing randomised controlled trial (ACTRN12622000072718) is evaluating the effect of this tool on patient willingness for surgery. Full results of this trial are expected to be available by April 2023. A free-to-use online version of the tool is available at . smartchoice.org.au.

Cryocompression therapy is a non-invasive and non-pharmacological modality used in managing acute post-operative inflammation and pain. A prospective, randomised controlled trial (RCT) was undertaken to evaluate the effectiveness of a post-operative cryocompression protocol using the Game Ready™ (GR) device versus usual care on recovery following total knee arthroplasty (TKA). A single centre RCT was conducted with 70 TKAs (68 patients) randomised to a 2-week intervention period consisting of treatment with GR cryocompression (n=33, 33.3% males) or a usual care protocol of ice with static compression using tubigrip (n=35, 54.3% males). Knee range of movement (ROM) (flexion and extension), a visual analogue pain score (VAS) and limb circumference were documented at day 1, 2 and 14, as well as 6 and 12 weeks post-surgery. ROM was also recorded at day 90, while medication use and length of hospital stay were documented. Patient reported outcome measures (PROMs) including the KOOS and patient satisfaction questionnaire were employed. The GR group demonstrated 2.3° more (p=0.05) knee extension ROM overall, as well as 2. 8° more at day 1 (p=0.048), 3.8° at day 14 (p=0.007) and 5.4° at 3 months (p=0.017). There were no group differences (p>0.05) observed in pain (VAS), flexion ROM, limb circumference, opioid use or other PROMs. Across the full cohort, higher pain levels resulted in increased opioid intake (p=0.002), older patients used significantly less opioids (p<0.001) and males reported significantly less pain (VAS) than females (p=0.048). Using GR following TKA is a safe, non-invasive tool that can be used to aid in the post-operative recovery period. Patients using the GR cryocompression device gained significantly more extension ROM compared to the conventional ice with compression group, despite no other group differences