The magnetic resonance aspect of a polyurethane meniscal scaffold is worse in advanced cartilage defects without deterioration of clinical outcomes after a minimum two-year follow-up

•New knowledge in the field of meniscal substitution of the knee treated with a polyurethane scaffold.•It is one of the largest series of patients treated with such implant.•The first that evaluates the effect of different degrees of articular cartilage lesions of the knee in the MRI aspect of this meniscal polyurethane scaffold and in the functional scores.

BackgroundMeniscal scaffolding is thought to provide functional improvement and to prevent cartilage degeneration. Advanced chondral injuries might damage the scaffold structural properties.ObjectiveTo evaluate the influence of different degrees of articular chondral injuries on the imaging aspect of a polyurethane meniscal scaffold (Actifit®).MethodsFifty-four patients operated on with an Actifit® were studied. The status of the articular cartilage in the involved compartment was classified according to ICRS. The characteristics of the implant were evaluated in MRI with the Genovese score. Functional scores included WOMET, IKDC and Kujala scores. The Genovese score was correlated with the degree of chondral injury and functional results.ResultsThe mean follow-up was 39 months (range 25-63). Additional procedures were performed in 69.5%. There were 19 patients without chondral injuries and 14 with grade 1, 10 with grade 3 and eight with grade 4 chondral lesions. The morphology and size of the implant on MRI scanning were worse with a higher degree of chondral injury (p = 0.023). WOMET, IKDC and Kujala improved from 36.2 SD ± 7.6, 32.3 SD ± 13.5 and 39.2 SD ± 8.1 to 75.8 SD ± 12.9 (p = 0.02), 75.5 SD ± 15.4 (p = 0.03) and 85.6 SD ± 13.4 (0.042), respectively. There was no relationship between the severity of chondral injury and functional scores.ConclusionsPatients without chondral injuries showed a better MRI aspect of the polyurethane scaffold in terms of size and morphology. By optimizing biomechanics, in particular the implantation of a meniscal substitute, significant pain relief and functional improvement were observed after a minimum two-year follow-up.Level of evidenceTherapeutic case series; level 4.