In vitro studies have shown that human osteoclasts can corrode stainless steel and titanium leading to the production of metal ions responsible for inflammatory reactions. Moreover, traces of cellular activities on metal orthopaedic explants have recently been reported as inflammatory cell-induced (ICI) corrosion being the result of the cells sealing on the metal surfaces and releasing reactive oxygen species (ROS) through Fenton-like reactions. The extent and clinical relevance of this phenomenon has yet to be understood. We analysed a cohort of 100 CoCr alloy hips collected at our retrieval centre; we performed macroscopic and microscopic screening and used statistical analysis to correlate our findings with implant and clinical variables. We found that 59% of our implants had evidence of surface damage consistent with what has previously been described as cell-induced corrosion. There was a significant association between the patterns and aseptic loosening for the ASR modular (r = -0.488, p = 0.016) and the Durom modular (r = 0.454, p = 0.026). This is the largest implant retrieval study to examine the phenomena of so-called ICI corrosion and is the first to investigate its clinical relevance. We recommend further work to determine the role of cells in the damage patterns observed. © 2015 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 105B: 155-164, 2017.

Three-dimensional (3D) printed titanium orthopaedic implants have recently revolutionized the treatment of massive bone defects in the pelvis, and we are on the verge of a change from conventional to 3D printed manufacture for the mass production of millions of off-the-shelf (non-personalized) implants. The process of 3D printing has many adjustable variables, which taken together with the possible variation in designs that can be printed, has created even more possible variables in the final product that must be understood if we are to predict the performance and safety of 3D printed implants. We critically reviewed the clinical use of 3D printing in orthopaedics, focusing on cementless acetabular components used in total hip arthroplasty. We defined the clinical and engineering rationale of 3D printed acetabular cups, summarized the key variables involved in the manufacturing process that influence the properties of the final parts, together with the main limitations of this technology, and created a classification according to end-use application to help explain the controversial and topical issues. Whilst early clinical outcomes related to 3D printed cups have been promising, in-depth robust investigations are needed, partly because regulatory approval systems have not fully adapted to the change in technology. Analysis of both pristine and retrieved cups, together with long-term clinical outcomes, will help the transition to 3D printing to be managed safely.

ObjectivesTo evaluate the short-term impact of long-distance running on knee joints using MRI.Methods82 healthy adults participating in their first marathon underwent 3T (Tesla) MRI of both knees 6 months before and half a month after the marathon: 71 completed both the 4 month-long standardised training programme and the marathon; and 11 dropped-out during training and did not run the marathon. Two senior musculoskeletal radiologists graded the internal knee structures using validated scoring systems. Participants completed Knee Injury and Osteoarthritis Outcome Score questionnaires at each visit for self-reporting knee function.ResultsPremarathon and pretraining MRI showed signs of damage, without symptoms, to several knee structures in the majority of the 82 middle-aged volunteers. However, after the marathon, MRI showed a reduction in the radiological score of damage in: subchondral bone marrow oedema in the condyles of the tibia (p=0.011) and femur (p=0.082). MRI did also show an increase in radiological scores to the following structures: cartilage of the lateral patella (p=0.0005); semimembranosus tendon (p=0.016); iliotibial band (p<0.0001) and the prepatellar bursa (p=0.016).ConclusionImprovement to damaged subchondral bone of the tibial and femoral condyles was found following the marathon in novice runners, as well as worsening of the patella cartilage although asymptomatic. This is the most robust evidence to link marathon running with knee joint health and provides important information for those seeking to understand the link between long distance running and osteoarthritis of the main weight-bearing areas of the knee.

Purpose It was the primary purpose of the present systematic review to identify the optimal protection measures during COVID-19 pandemic and provide guidance of protective measures for orthopedic surgeons. The secondary purpose was to report the protection experience of an orthopedic trauma center in Wuhan, China during the pandemic. Methods A systematic search of the PubMed, Cochrane, Web of Science, Google Scholar was performed for studies about COVID-19, fracture, trauma, orthopedic, healthcare workers, protection, telemedicine. The appropriate protective measures for orthopedic surgeons and patients were reviewed (on-site first aid, emergency room, operating room, isolation wards, general ward, etc.) during the entire diagnosis and treatment process of traumatic patients. Results Eighteen studies were included, and most studies (13/18) emphasized that orthopedic surgeons should pay attention to prevent cross-infection. Only four studies have reported in detail how orthopedic surgeons should be protected during surgery in the operating room. No detailed studies on multidisciplinary cooperation, strict protection, protection training, indications of emergency surgery, first aid on-site and protection in orthopedic wards were found. Conclusion Strict protection at every step in the patient pathway is important to reduce the risk of cross-infection. Lessons learnt from our experience provide some recommendations of protective measures during the entire diagnosis and treatment process of traumatic patients and help others to manage orthopedic patients with COVID-19, to reduce the risk of crossinfection between patients and to protect healthcare workers during work. Level of evidence IV.

Objective To identify abnormalities in asymptomatic sedentary individuals using 3.0 Tesla high-resolution MRI. Materials and methods The cohort comprised of 230 knees of 115 uninjured sedentary adults (51 males, 64 females; median age: 44 years). All participants had bilateral knee 3.0 T MRIs. Two senior musculoskeletal radiologists graded all intraarticular knee structures using validated scoring systems. Participants completed Knee Injury and Osteoarthritis Outcome Score questionnaires at the time of the MRI scan. Results MRI showed abnormalities in the majority (97%) of knees. Thirty percent knees had meniscal tears: horizontal (23%), complex (3%), vertical (2%), radial (2%) and bucket handle (1%). Cartilage and bone marrow abnormalities were prevalent at the patellofemoral joint (57% knees and 48% knees, respectively). Moderate and severe cartilage lesions were common, in 19% and 31% knees, respectively, while moderate and severe bone marrow oedema in 19% and 31% knees, respectively. Moderateintensity lesion in tendons was found in 21% knees and high-grade tendonitis in 6% knees-the patellar (11% and 2%, respectively) and quadriceps (7% and 2%, respectively) tendons being most affected. Three percent partial ligamentous ruptures were found, especially of the anterior cruciate ligament (2%). Conclusion Nearly all knees of asymptomatic adults showed abnormalities in at least one knee structure on MRI. Meniscal tears, cartilage and bone marrow lesions of the patellofemoral joint were the most common pathological findings. Bucket handle and complex meniscal tears were reported for the first time in asymptomatic knees.

We report on the accuracy, measured with three‐dimensional (3D) computed tomography (CT) postoperatively, in positioning custom 3D printed titanium components in patients with large acetabular defects. Twenty patients (13 females and 7 males) received custom‐made acetabular implants between 2016 and 2018; the mean age was 66 years (SD = 11.6) and their mean body mass index was 28 (SD = 6.1). The median time to follow up was 25.5 months, range: 12 to 40 months. We describe a comparison method that uses the 3D models of CT‐generated preoperative plans and the postoperative CT scans to quantify the discrepancy between planned and achieved component positions. Our primary outcome measures were the 3D‐CT‐measured difference between planned and achieved a component position in six degrees of freedom: center of rotation (CoR), component rotation, inclination (INC), and version (VER) of the cup. Our secondary outcome measures were: Oxford hip score, walking status, and complication rate. All components (100%) were positioned within 10 mm of planned CoR (in the three planes). Eighteen (95%) components were not rotated by more than 10° compared to the plan. Eleven (58%) components were positioned within 5° of planned cup angle (INC and VER). To date one complication has occurred, a periprosthetic fracture. This is the largest study in which postoperative 3D‐CT measurements and clinical outcomes of custom‐made acetabular components have been assessed. Accurate pre‐op planning and the adoption of custom 3D printed implants show promising results in complex hip revision surgery.

The mechanisms of metal release from the articulation at the head cup bearing and the tapered junctions of orthopaedic hip implants are known to differ and the debris generated varies in size, shape and volume. Significantly less metal is lost from the taper junction between Cobalt-Chromium-Molybdenum (CoCrMo) and Titanium (Ti) components (fretting-corrosion dominant mechanism), when compared to the CoCrMo bearing surfaces (wear-corrosion dominant mechanism). Corrosion particles from the taper junction can lead to Adverse Reactions to Metal Debris (ARMD) similar to those seen with CoCrMo bearings. We used synchrotron methods to understand the modes underlying clinically significant tissue reactions to Co, Cr and Ti by analysing viable peri-prosthetic tissue. Cr was present as Cr2O3 in the corroded group in addition to CrPO4 found in the metal-on-metal (MoM) group. Interestingly, Ti was present as TiO2 in an amorphous rather than rutile or anatase physical form. The metal species were co-localized in the same micron-scale particles as result of corrosion processes and in one cell type, the phagocytes. This work gives new insights into the degradation products from metal devices as well as guidance for toxicological studies in humans.

Dual-mobility (DM) cups have been clinically used in hip surgery in Europe for more than 35 years and continue to gain popularity worldwide due to promising results at reducing instability. Concerns related to polyethylene wear apply as in conventional standard bearings but are accentuated by the larger-diameter articulations with multiple surfaces. We critically reviewed the reported literature regarding the in vivo and in vitro wear occurring on all surfaces involved. We looked for patterns to create a rational classification of sites of wear and to identify areas for future research. Wear was a significant problem for first-generation designs and appeared to be design related. Improved polyethylene, thinner and smoother trunnions, chamfered rims and eccentric configuration of insert and shell seem to enhance outcome performance; however, long-term clinical evidence and retrieval studies are needed to better understand the balance of benefit and risk when opting for DM bearings.