Purpose Planned interim analysis of GENESIS; a prospective pilot study investigating the role of genicular artery embolization (GAE) in patients with mild to moderate osteoarthritis of the knee using permanent microspheres. Methods Thirty-eight patients, median age = 60 (45–83), attended for GAE using 100–300 μm permanent microspheres. All patients had mild to moderate knee OA, resistant to conservative treatments over 6 months. Knee MRI was performed at baseline, and 12 months, enabling semi-quantitative analysis using Whole-Organ Magnetic Resonance Imaging Score (WORMS). Knee Injury and Osteoarthritis Outcome Score (KOOS) and visual analogue scale (VAS) (0–100 mm) were completed at baseline, 6 weeks, 3 months (n = 32), and 1-year (n = 16). Adverse events were recorded prospectively. Results Technical success of accessing and embolizing the target genicular arteries was 84%. Six patients were not embolized: four due to a presumed risk of non-target embolization, and two due to a lack of hyperaemic target. Mean VAS improved from 60 (SD = 20, 95% CI 53–66) at baseline to 36 (SD = 24, 95% CI 28–44) at 3 months (p < 0.001) and 45 (SD = 30, 95% CI 30–60) at 1-year (p < 0.05). All KOOS subscales showed a significant improvement at 6-weeks, 3-months, and 1-year follow-up, except function in daily living, which reached borderline significance (p = 0.06) at 1-year. Four patients experienced mild self-limiting skin discoloration over the embolized territory. One patient experienced a small self-limiting groin haematoma. WORMS scores at 1-year follow-up showed significant improvement in synovitis (p < 0.05). There were no cases of osteonecrosis. Conclusion GAE using permanent microspheres in patients with mild to moderate knee OA is safe, with potential efficacy at early follow-up.

Artifact from metallic orthopedic prosthesis is caused by inhomogeneity in the B0 magnetic field, particularly in the frequency encoding direction. This results in signal voids, signal pileup, and geometric distortion. Advances in reducing this artifact allow us to assess the complications of joint replacement and improve imaging of nearby tissues such as within the pelvis. Selection of titanium implants and lower field strength MR units provide optimal conditions for artifact reduction. Conventional sequences can be optimized by using inversion recovery sequences, large matrices, high receiver bandwidths, and thin slices. Optimizing these parameters comes with a penalty in terms of signal-to-noise ratio or increased acquisition times. Successful artifact reduction depends on the strength of the frequency encoding gradients. Newer dedicated artifact reduction sequences include view-angle-tilting and a selection of multispectral techniques including multiacquisition variable-resonance image combination (MAVRIC) and slice encoding for metal artifact correction (SEMAC). Many of these are being used in combination. The multispectral sequences acquire three-dimensional data at very narrow frequencies and use of phase encoding for spatial localization. Planar images can then be reconstructed with very little susceptibility artifact.

Human error is an inevitable cause of patient harm. Safety checks are a simple method of reducing the risk of harm using a periprocedural routine to reduce the likelihood of error.Safety checklists have been in use in the aviation industry since the late 1930s. In 1935, a prototype Boeing B-17 bomber crashed during a test flight, killing two experienced test pilots, leading to the development of more formalised cockpit safety checklist. 1 'At the controls of the Model 299 this day were two experienced Army pilots….The aircraft made a normal taxi and takeoff. It began a smooth climb, but then suddenly stalled. The aircraft turned on one wing and fell, bursting into flames upon impact….. The investigation found "Pilot Error" as the main cause of the accident. Hill, unfamiliar with the aircraft, had neglected to release the elevator lock prior to take off. Once airborne, Tower evidently realized what was happening and tried to reach the lock handle but by that time it was too late.The pilots sat down and put their heads together. What was needed was some way of making sure that everything was done properly; that nothing was overlooked. What resulted was a pilot's checklist. In the end, four checklists were developed -take off, flight, before landing, and after landing. As it turned out, the Model 299 was not "too much airplane for one man to fly, "-it was simply too complex for any one male's memory. These checklists for both the pilot and the co-pilot made sure that nothing was forgotten.With these new checklists, careful planning and rigorous training, the twelve aircraft managed to fly 1.8 million miles without a serious accident….The B-17 went on to become the most widely used aircraft in WWII.'

One of the patients in the interim analysis was diagnosed with a popliteal deep vein thrombosis (DVT) 15 days after GAE in the same leg. The patient was treated with oral anticoagulation and made a full recovery. Whilst this is unlikely to be directly related to the GAE procedure, it highlights the risk of DVT in patients with knee OA and immobility. It is important to be aware of this when following up patients undergoing GAE for knee OA.

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