Partial Meniscal Replacement with Spongioflex®

for any surgical procedure, the patient receives an antibiotic shot NIMP) just before surgery. The patient will be arthroscopically treated via the arthroscopic portal with implantation of a demineralized bone block (IMP: Spongioflex ®, appropriate size (DIZG gGmbH, Berlin, Germany)) as a partial meniscus substitute. The block will be adapted to the defect size and secured with 2-4 inside-out sutures (Etibond 0, Ethicon, Somerville, NJ). No dosing, the IMP has no systemic effect. The surgery (Intervention) will last between 60-90 minutes. The hospital stay is between 2-3 days after surgery. Follow-up visits: at the end of the hospital stay, after 6 weeks, after 6, 12 and 24 months and after 5 years for the operated group.