Purpose Collagen meniscal implants (CMI) have variable imaging indings on MRI and it remains ambiguous, if alterations may be present in asymptomatic patients. The aim was, to evaluate MR morphological characteristics and volume of CMI in the early, mid-and long-term follow-up. Methods Fifty-seven patients (mean age, 43.6±11 years; 41 male/16 female) with good clinical outcome (subjective visual analogue scale for satisfaction < 2 and a Lysholm-score ≥ 84) after CMI were assessed retrospectively using MRI 1, 2 and 3-8 years postoperatively. CMI morphology, signal intensity (SI), homogeneity and size were assessed and a meniscal score was calculated. Chondral defects and bone marrow edema pattern were reported and summarized in a chondral score. Meniscal extrusion and volume were evaluated. Intra-and inter-reader reliabilities were calculated. Spearman and partial correlations were used (p < 0.05). Results One year postoperatively, the CMI varied in size [10% (4/40) normal, 30% (12/40) small, 60% (24/40) hypertrophic] and was hyperintense and inhomogeneous in all patients. At long-term follow-up, the size of CMI decreased [6% (1/17) resorbed, 18% (3/17) normal, 41% (7/17) small, 35% (6/17) hypertrophic]. The SI of the CMI changed to normal in only 13% (2/16). The majority was still hyperintense [87% (14/16)]. Less meniscal extrusion was present in the follow-up [71% (11/16) versus initially 93% (37/40)]. The meniscal score improved signiicantly (ρ = 0.28). Over time, full-thickness femoral chondral defects were increasingly present [65% (10/17) versus initially 33% (13/40)] and the chondral score worsened signiicantly (p = 0.017). Conclusion Abnormal and inhomogeneous SI and irregular margins of the early postoperative CMI on MRI are indings seen in patients with good clinical results and should not necessarily be overcalled when reporting MRI. These features tend to decrease over time. Level of evidence IV.

Purpose: To evaluate the feasibility and safety of a coaxial dual-wavelength optical coherence tomography (OCT) device (marked as Hydra-OCT). Methods: Healthy participants without ocular pathology underwent retinal imaging using the Hydra-OCT allowing for simultaneous measurement of retinal scanning of 840 and 1,072 nm wavelength. Before and after measurement, best-corrected visual acuity and patients’ comfort were assessed. Representative OCT images from both wavelengths were compared by 5 independent graders using a subjective grading scheme. Results: A total of 30 eyes of 30 participants (8 females and 22 males) with a mean age of 26.5 years (range from 19 to 55 years) were included. Dual-wavelength image acquisition was made possible in each subject. The participant’s effort and comfort assessment using the Hydra-OCT imaging revealed an equivalent value as compared to the commercially available OCT machine. No adverse events were reported, and visual acuity was not altered by the Hydra-OCT. Imaging between the systems was comparable. Conclusions: This study provides evidence for the feasibility and safety of a coaxial dual-wavelength OCT imaging method under real-life conditions. The novel Hydra-OCT imaging device may offer additional insights into the pathology of retinal and choroidal diseases.