Background

A biodegradable polyurethane scaffold was developed to treat the challenging clinical condition of patients with painful partial meniscal defects.

Hypothesis

The application of an acellular polyurethane scaffold in symptomatic partial meniscal defects results in both midterm pain relief and improved function.

Study Design:
Case series; Level of evidence, 4.

Methods

A total of 155 patients with symptomatic partial meniscal defects (101 medial and 54 lateral) were implanted with a polyurethane scaffold (Actifit?,Orteq Ltd) in a prospective, single-arm, multicentric study with a minimum 5-year follow-up. Clinical outcomes were measured with the visual analog scale (VAS) for pain, International Knee Documentation Committee (IKDC), Lysholm Knee Scale and Knee injury and Osteoarthritis Outcome Score (KOOS) at baseline and at 2- and 5-year follow-up. Magnetic resonance imaging (MRI) was used to evaluate the knee joint, meniscal implant and meniscal extrusion. Kaplan-Meier time-to–treatment failure analysis wqs also performed. Removal of the scaffold, conversion to a meniscal transplant, or unicompartmental/total knee arthroplasty were used as endpoints.

Results

Eighteen patients were lost to follow-up (11.0%). The patients who were included in this study showed significant clinical improvement after surgery as indicated by the different outcome measurements. However, the clinical improvement tend to stabilize between 2 and 5 years of follow-up. MRI of the scaffolds showed in the majority of the cases a smaller sized implant when compared with the native meniscus with an irregular surface at 5-year follow-up. During the follow-up period, 87.9% of the implants survived in this study. At 5 years of follow-up, 87.9% of the medial scaffolds were still functioning versus 86.1% of the lateral scaffolds.

Conclusion

The polyurethane meniscal implant is able to improve knee joint function and significantly reduce pain in patients with segmental meniscus deficiency over 5 years after implantation. The MRI appearance of this scaffold is different than the original meniscal tissue at midterm follow-up. The treatment survival rates of 87.9.9% of the medial scaffolds and 86.1% of the lateral scaffolds in the present study compares similar to those published concerning meniscal allograft transplantation after total meniscectomy.