史赛克

Femoral component surface roughness is a critical determinant of polyethylene wear in total knee arthroplasty (TKA). Titanium nitride (TiN) ceramic surface coatings have been developed to improve wear resistance and address concerns related to metal hypersensitivity; however, comprehensive wear data remain limited. This knee simulator study evaluated the performance of TiN-coated titanium alloy (6 wt% aluminum, 4 wt% vanadium, balance titanium, Ti-6Al-4V) substrate femoral components compared with cobalt chromium (CoCr) femoral components. Mode I wear testing was conducted for 5.0 million cycles (mc) using highly crosslinked polyethylene tibial inserts, with wear rates and polyethylene debris morphology quantified. Mode III third-body abrasive wear testing was performed on TiN-coated femoral components using embedded 500 µm TiN-coated particles for 3.0 mc. Surface roughness was measured using White Light Interferometry (arithmetic mean height, Sa), and surface integrity was assessed using scanning electron microscopy. Following 5.0 mc of Mode I wear, volumetric wear rates were equivalent between TiN-coated and CoCr femoral components (1.03 vs 1.04 mm3/million cycles; p = 0.001), with no notable differences in polyethylene particle size (p = 0.114) or morphology. During third-body testing, surface scratching of the TiN coating was observed without evidence of gross surface failure. As anticipated, the mean Sa of TiN-coated femoral components increased through 3.0 mc of Mode III third-body testing, while remaining lower than literature-reported retrieved CoCr values (p = 0.001). In conclusion, TiN-coated femoral components demonstrated comparable in vitro adhesive wear performance to CoCr and provided improved resistance to abrasive conditions, where long-term resistance to abrasion is expected to govern reduced wear.

Shoulder arthroplasty has become an established treatment option for displaced and complex proximal humeral fractures, particularly in elderly patients. Fracture-specific stems are increasingly used in clinical practice; however, early data on surgeon experience with newly introduced convertible stem designs remain limited. This study aimed to assess orthopedic surgeons’ early intraoperative experience with a newly developed humeral fracture system (Tornier Perform Humeral System – Fracture, Tornier Inc., a wholly owned subsidiary of Stryker, Bloomington, MN, USA) using a structured survey as part of an early product surveillance program. A prospective observational survey was conducted among orthopedic surgeons in the United States and Canada who had performed surgery using the fracture stem. Case-level evaluations of intraoperative handling, technical features, and surgeon-reported comparisons with routinely used implant systems were collected. Descriptive statistics were used to summarize survey responses. Twenty-six orthopedic surgeons submitted feedback on 47 surgical cases (45 primary cases, 2 revisions), including predominantly reverse configurations (46/47) and one hemiarthroplasty construct. All available stem fixation methods were used: cementless without interlocking screws (n = 24), cementless with interlocking screws (n = 14), and cemented (n = 9). Surgeons reported high levels of satisfaction and favorable ratings for ease of use. Across multiple comparative dimensions, the fracture system was frequently rated favorably compared with surgeons’ routinely used systems. Twenty-five of 26 participating surgeons indicated that they would consider using the system in future cases and would recommend it to others (missing data for one surgeon). Qualitative feedback described perceived benefits related to specific design features, including press-fit capability, bone graft window, proximal stem design, and the option for interlocking screw fixation. Surgeons reported favorable early intraoperative impressions of this fracture system. These findings provide exploratory insights into surgeon-reported usability and perceived design characteristics under early real-world use. Further studies are required to evaluate the clinical relevance of these surgeon-reported perceptions. IV.

Background Out-of-hospital cardiac arrest (OHCA) treatment often requires multiple defibrillatory shocks due to failed defibrillation or refibrillation. The complete nature of refractory ventricular fibrillation (VF) is unknown, as many studies do not consider shocks delivered by lay rescuers prior to the arrival of basic life support (BLS)/advanced life support (ALS) when quantifying refractory VF. ERC guidelines define refractory VF as continuous VF after three consecutive shocks, not differentiating between patients who refibrillate and those with shock-resistant VF (three consecutive failed shocks) which may contribute to this variation in reported incidence. There are some differences in treatment recommendations for patients who refibrillate and those with shock-resistant VF. Therefore, understanding the number of shocks delivered by lay-rescuers with public access defibrillators (PADs) and the patient’s response to them prior to BLS/ALS arrival may inform treatment strategies. Methods ECG data collected retrospectively from OHCAs treated by lay-rescuers using PADs were analysed. Cardiac rhythm, shock success, refibrillation, time to refibrillation and presence of shock-resistant VF (three consecutive failed shocks) were determined by two investigators. Results Data were available for 1459 patients receiving at least one shock. Refibrillation occurred in 498 (34.1%) patients. The median number of refibrillations per patient was 1 (IQR 1, 2). Median time to refibrillation was 29.8 s. Three consecutive shocks were observed in 231 of the 1459 (15.8%) patients, 11 patients (4.8% of 231 patients) had shock-resistant VF. Conclusion When treated by lay-rescuers with PADs, refibrillation occurrence is lower than that reported for patients treated by BLS/ALS. However, aligned with BLS/ALS studies, in lay-rescuer treated OHCA, refibrillation typically occurs within the first 30 s following a successful shock. Therefore, patients who refibrillate are typically in VF for an additional 1.5 min before receiving a subsequent shock for PADs with a 2 min cardiopulmonary resuscitation (CPR) cycle. This finding emphasises the need for investigation into optimal CPR duration for patients requiring multiple shocks.

Femoral and tibial component malalignment in total knee arthroplasty has been associated with postoperative instability, patient dissatisfaction, and early component failure. Precise placement and rotational alignment are therefore critical to achieving optimal clinical results. Femoral and tibial component positioning relies on identification of bony landmarks relative to native anatomy. Previous studies have demonstrated that manual identification of these landmarks is inconsistent; however, few studies have directly compared manual probe identification with computed tomography (CT) measurements. The purpose of this study was to compare variability in femoral and tibial landmark identification using manual probing versus CT-based identification. Femoral and tibial bony landmarks were identified on six cadaver knees by two evaluator groups, including the anterior trochlear groove, intercondylar notch, medial and lateral posterior femoral condyles, medial and lateral epicondyles, tibial tubercle, medial and lateral tibial plateau, and medial and lateral malleoli. The first group consisted of three fellowship-trained arthroplasty surgeons who identified landmarks intraoperatively using a manual probe, whereas the second consisted of three evaluators who identified landmarks digitally on corresponding preoperative CT scans. Each landmark was identified three times with rotation between specimens for randomization, and data were collected using a robotic system. The three-dimensional landmark locations were converted into a distance value, and variation between landmarks was analyzed. A two-sample student t-test was utilized to evaluate statistical significance at p < 0.05. The CT-based identification demonstrated decreased variation than manual probe techniques across all landmarks. Statistically significant reductions in variability were observed for the anterior trochlear groove (p < 0.001), medial posterior femoral condyle (p = 0.010), lateral posterior femoral condyle (p = 0.021), medial epicondyle (p = 0.006), lateral tibial plateau (p = 0.029), and lateral malleolus (p = 0.028). Identification using CT-based techniques of femoral and tibial landmarks demonstrated less variability than manual probing, which may lead to more consistent implant component placement. Further studies are needed to determine the influence of landmark variation on component positioning.