Purpose: This clinical fluoroscopy study investigated knee kinematics of two different cemented fixed-bearing, posterior-stabilised (PS) total knee arthroplasty (TKA) designs: an asymmetric tibial component including an asymmetric insert designed to optimise personalised balance and fit and its precursor symmetrical design with symmetric insert. Methods: A consecutive series of patients (16 TKAs from each treatment group) participating in a randomised controlled trial comparing TKA migration was included. The exclusion criterion was the use of walking aids. Flat-panel fluoroscopic recordings of step-up and lunge motions were acquired 1-year postoperatively. Medial and lateral contact points (CPs) were determined to calculate CP displacement, femoral axial rotation and pivot position. Using linear mixed-effects modelling techniques, kinematics between TKA designs were compared. Results: During knee extension between 20 degrees flexion and full extension, the CPs moved anteriorly combined with a small internal femoral rotation (a screw-home mechanism). Whereas CP movement was reversed: femoral rollback, external femoral rotation while flexing the knee between full extension and 20 degrees knee flexion, At larger flexion angles, femoral axial rotation (FAR) occurred around a lateral pivot point both during step-up and lunge. The symmetric design had a 2.3 degrees larger range of FAR compared to the asymmetric design during lunge (p = 0.02). All other kinematics were comparable. Conclusion: Despite the differences in design, this study showed that the asymmetric and symmetric PS TKA designs had mostly comparable knee kinematics during step-up and lunge motions. It is therefore expected that the functionality of the successor TKA design is similar to that of its precursor design.

BACKGROUND:Despite the excellent success and safety of intravascular lithotripsy (IVL) in heavily calcified lesions, evidence in acute coronary syndromes (ACS) remains limited. AIMS:This study aimed to evaluate the procedural and clinical outcomes of IVL in heavily calcified ACS. METHODS:Patients who underwent IVL between 2019 and 2024 from the ongoing prospective BENELUX registry were eligible for inclusion. Patients were therefore classified in ACS and chronic coronary syndrome (CCS) groups. The primary technical endpoint was angiographic success < 30%, defined as the successful delivery of the IVL catheter across the target lesion and delivery of IVL pulses without angiographic complications and residual target lesion less than 30%. The primary clinical endpoint was in-hospital major adverse cardiac events (MACE), including cardiac death, nonfatal myocardial infarction, or target lesion revascularization. RESULTS:A total of 454 patients underwent IVL, with 251 (55.3%) treated for CCS and 203 (44.7%) for ACS. The median SYNTAX score (p-value 0.17), the need for inotropes (p-value 0.09), and the use of mechanical circulatory support (p-value 0.71) were similar between CCS and ACS groups. Comparable angiographic success (< 30% residual stenosis) was observed between CCS and ACS groups (90.1% vs. 91.1%, p = 0.69). MACE were similar across groups during hospital stays (CCS 1.6% vs. ACS 3.0%, p = 0.33), at 30 days (CCS 3.2% vs. ACS 3.9%, p = 0.86), and at 12-month follow-up (CCS 8.4% vs. ACS 7.9%, p = 0.91). CONCLUSION:IVL provides high procedural success and consistent clinical outcomes in both CCS and ACS cases.

Likely due to ignored heterogeneity in disease pathophysiology, osteoarthritis (OA) has become the most common disabling joint disease, without effective disease-modifying treatment causing a large social and economic burden. In this study we set out to explore responses of aged human osteochondral explants upon different OA-related perturbing triggers (inflammation, hypertrophy and mechanical stress) for future tailored biomimetic human models. Human osteochondral explants were treated with IL-1β (10 ng/ml) or triiodothyronine (T3; 10 nM) or received 65% strains of mechanical stress (65% MS). Changes in chondrocyte signalling were determined by expression levels of nine genes involved in catabolism, anabolism and hypertrophy. Breakdown of cartilage was measured by sulphated glycosaminoglycans (sGAGs) release, scoring histological changes (Mankin score) and mechanical properties of cartilage. All three perturbations (IL-1β, T3 and 65% MS) resulted in upregulation of the catabolic genes MMP13 and EPAS1. IL-1β abolished COL2A1 and ACAN gene expression and increased cartilage degeneration, reflected by increased Mankin scores and sGAGs released. Treatment with T3 resulted in a high and significant upregulation of the hypertrophic markers COL1A1, COL10A1 and ALPL. However, 65% MS increased sGAG release and detrimentally altered mechanical properties of cartilage. We present consistent and specific output on three different triggers of OA. Perturbation with the pro-inflammatory IL-1β mainly induced catabolic chondrocyte signalling and cartilage breakdown, while T3 initiated expression of hypertrophic and mineralization markers. Mechanical stress at a strain of 65% induced catabolic chondrocyte signalling and changed cartilage matrix integrity. The major strength of our ex vivo models was that they considered aged, preserved, human cartilage of a heterogeneous OA patient population. As a result, the explants may reflect a reliable biomimetic model prone to OA onset allowing for development of different treatment modalities.

AIMS The objective of this study was to compare the two-year migration pattern and clinical outcomes of a total knee arthroplasty (TKA) with an asymmetrical tibial design (Persona PS) and a well-proven TKA with a symmetrical tibial design (NexGen LPS). METHODS A randomized controlled radiostereometric analysis (RSA) trial was conducted including 75 cemented posterior-stabilized TKAs. Implant migration was measured with RSA. Maximum total point motion (MTPM), translations, rotations, clinical outcomes, and patient-reported outcome measures (PROMs) were assessed at one week postoperatively and at three, six, 12, and 24 months postoperatively. RESULTS A linear mixed-effect model using RSA data of 31 asymmetrical and 38 symmetrical TKAs did not show a difference in mean MTPM migration pattern of the tibial or femoral components. Mean tibial component MTPM at two years postoperative of the asymmetrical TKA design was 0.93 mm and 1.00 mm for the symmetrical design. For the femoral component these values were 1.04 mm and 1.14 mm, respectively. No significant differences were observed in other migration parameters or in clinical and PROM measurements. CONCLUSION The TKA design with an asymmetrical tibial component has comparable component migration with the proven TKA with a symmetrical tibial component. This suggests the risk of long-term aseptic loosening of the two designs is comparable. Cite this article: Bone Joint J 2021;103-B(5):855-863.

Objectives Dutch ‘Choosing Wisely’ recommendations were developed to reduce routine use of MRI and arthroscopy in degenerative knee disease. An active de-implementation strategy was developed to effectuate these CW-recommendations in orthopaedic practice. This study evaluated the feasibility and effectiveness of this de-implementation strategy to reduce the use of MR’s and knee arthroscopies in orthopaedic practice using an interruptive time series design. Methods Based on previously assessed barriers and facilitators among both patients and orthopaedic surgeons, we developed a de-implementation strategy to reduce MRI and arthroscopy use. The strategy included five components: local clinical leaders, education about guidelines and corresponding literature, hospital-specific feedback on MRI and knee arthroscopy use, video about expectation management, and a patient brochure. The feasibility and effectiveness of this strategy is evaluated in 13 orthopaedic centers distributed across the Netherlands. Hospital data from March 2016 till December 2018 were analysed using an interrupted-time series design. The primary outcomes were MRI and knee arthroscopy use in degenerative knee disease among patients aged 50 years and over. In addition, a process evaluation was performed among all local clinical leaders, orthopaedic surgeons and residents who participated in this study to determine the feasibility and effectiveness of the de-implementation strategy. Results Preliminary results show a downward trend for MRI use among patients with degenerative knee disease (13.6% before versus 5.7% after execution of the de-implementation strategy). Use of knee arthroscopy also decreased for this patient group (before: 9.4%, after: 3.8%). From the process evaluation it appeared that orthopaedic surgeons and residents felt that the education about guidelines and corresponding literature, and the patient brochure had the most added value for enable implementation of the ‘Choosing Wisely’ guidelines in practice. Data collection will be completed in June 2018 and are needed to assess the full effect. Conclusion From the preliminary data both MRI and arthroscopy use have been reduced. However, it is not yet known whether this was part of general downward trend in MRI and arthroscopy use in degenerative knee disease or that the de-implementation strategy significantly changed this trend, for which we have to await the final data. Authors in the Smart study group: P. Pander, K.L.M. Koenraadt, R.C.I. van Geenen, J.P.A.H. Onderwater, Y.V. Kleinlugtenbelt, T. Gosens, T.V.S. KLOS, P.C. Rijk, A.V.C.M. Zeegers, R.A.G. Hoogeslag, R. Huis in ‘t Veld, A.A. Polak, N.R.P. Pereira

Background:Although the value of physical therapy ( PT) in the rehabilitation of patients undergoing THA and TKA is generally acknowledged, little is known on the actual extent of its delivery and contents. This study aimed to describe the use, characteristics, and determinants of preoperative and postoperative PT in THA and TKA.Methods:One thousand and five patients who underwent THA or TKA in four hospitals in the preceding 7-22 mo were invited to complete a survey on referral, setting, duration, and content regarding preoperative and postoperative PT as well as their current level of physical functioning (Hip Disability and Osteoarthritis Outcome [HOOS] and Knee Injury and Osteoarthritis Outcome Score [KOOS]) and quality of life (Short Form-36 [SF-36]). The association between patients' characteristics (age and sex), hospital stay, and time since surgery on the one side and the provision of PT on the other and between PT usage and physical function and quality of life were analyzed by multivariable logistic and linear regression analyses.Results:In total, 210 of the 522 responders (54% THA and 46% TKA) patients had preoperative PT (40%; 44% > 12 wk; 38% >= 2 times per week) and 514 postoperative PT (99%; 47% >= 12 wk; 67% >= 2 times per week). The most frequently reported interventions (p > 60% of patients) preoperatively were aerobic exercises and walking stairs and postoperatively, aerobic, muscle strengthening and range of motion exercises, walking stairs, and gait training. Regarding preoperative PT, female sex was the only factor associated with its provision. Moreover, the hospital was related to the proportion of referrals made by the orthopaedic surgeon, and a longer follow-up time since surgery was associated with a lower rate of provision of physical modalities. For postoperative PT, the hospital was associated with duration of PT and the provision of passive exercises, whereas older age was associated with fewer referrals by orthopaedic surgeons and treatment duration less than 12 wk, and female sex was associated with a treatment duration longer than 12 wk. A longer duration of postoperative PT was only associated with a worse physical quality of life, whereas preoperative PT use and the frequency of postoperative PT were not associated with any aspect of the patients' current health status.Conclusions:Almost all patients undergoing THA or TKA received postoperative PT, whereas fewer than half had preoperative PT. There was considerable variation in the provision of preoperative and postoperative PT in part associated with patient and hospital characteristics and time since surgery, warranting the need for more prospective research into potential practice variation.

The need for a better understanding of factors that influence surgical outcome has grown as many complications are thought to be avoidable. One approach proven useful in studying surgical procedures is time-action analysis (TAA), a method which objectively determines the efficiency of individual steps. The aim of this study was to assess the surgical process of total knee arthroplasty using TAA, thus enhancing the insight into the procedure, influence of team members and adverse events, eventually leading to process improvement and reduction of error probability. Methods: In two high output centres and one teaching hospital 37 TKA surgeries were recorded, using 3 different knee systems (NexGen, LCS and Triathlon). The process was analyzed using a fixed taxonomy and the duration, limitations and repetitions were determined using video analysis software. The efficiency of the surgeon was calculated by dividing the time the surgeon spends operating by the time operating plus the time spent talking, thinking or repeating. Results: Although the two high output centres used different knee systems there was no difference in operating time (47min. (95%CI, 43.2 to 50.1) versus 47min. (42.1 to 51.9)). With an inexperienced nurse the waiting time increased in both hospitals during the femoral osteotomy phase (p= 0.01 and p=0.05). Comparing to a training hospital, the tibial alignment phase showed lower surgical efficiency for both the consultant and 6th year residents (80% vs. 95%, p=0.01). Also the nurse waiting time increased during all phases (18min. vs. 2min., p=0.00). In the teaching hospital more problems (communication, instrument and skill) occurred (mean 19 vs. 5 and 2, p=0.00) and twice as much communication problems existed with residents regardless of nurse experience. Surprisingly the number of problems handling instruments increased inversely with nurse experience (p=0.02) as did the waiting time (27min. vs. 15min.) again being highest in the femoral osteotomy phase (p=0.00). Conclusion: The similar results in the high output centres show that TKA is a similar and structured process regardless of the knee system, its efficiency mainly dependent on surgical output. The decrease in resident efficiency is caused by less structured use of instruments and miscommunication with the nurse. For nurses the femoral osteotomy phase is most difficult, requiring high attention due to frequent changing of different pins and cutting blocks. Unfamiliarity with instruments (i.e. low volume) results in higher waiting times. Regardless of the knee system the steps of TKA are similar, therefore a consistent surgeon-nurse (OR tech) verbal interaction is advocated especially with a less experienced team. Training should focus knowledge of instruments using uniform names. Extra attention should be paid by those who do not often place knees to communication with the nurse and clear order of the procedure.

We evaluated the influence of CT-free or CT-based computer assisted orthopaedic surgery (CAOS) on the alignment of total knee prostheses (TK) and micromotion of tibial components. This randomised study compared 19 CT-free, 17 CT-based CAOS TK, and a matched control group of 21 conventionally placed TK. Using Roentgen stereophotogrammetric analysis (RSA) the migration was measured. The alignment and component positions were measured on radiographs. No significant difference in leg and tibial component alignment was present between the three groups. A significant difference was found for micromotion in subsidence, with the conventional group having a mean of 0.16 mm, compared to the CT-free group at 0.01 mm and the CT-based group at −0.05 mm. No clinical significant difference in alignment was found between CAOS and conventionally operated TK. More subsidence of the tibial component was seen in the conventional group compared to both CAOS groups at two year follow-up.