CLINICAL EFFICACY AND TISSUE INGROWTH FOLLOWING IMPLANTATION OF A AN AVASCULAR SYNTHETIC SCAFFOLD FOR TREATMENT OF IRREPARABLE MENISCUS TEARS

Abstract

Introduction: Post meniscectomy syndrom is an unfavorable disabling outcome for too many patients. This has led to intensive research into finding Methods: for treating irreparable meniscal lesions. The Actifit™ device is a biodegradable, porous, synthetic scaffold for treatment of irreparable partial meniscal tissue loss. When connected to the vascularized zone of the meniscus it promotes blood vessel ingrowth and new tissue generation.

Materials and Methods: Patients with irreparable partial meniscus loss into the vascular zone, intact rim, stable knee or joint stabilization within 3 months post surgery, ICRS classification £ 2, and £ 3 previous surgeries on index knee, and no significant malalignment were treated with the device in a non-randomised, single-arm, multi-centre study. Safety was assessed by frequency of serious adverse device effects (SADEs) and implantation-related serious adverse events (SAEs). Efficacy was assessed based on pain (Visual Analogue Scale [VAS] score) and function (Knee and Osteoarthritis Outcome Score [KOOS] and International Knee Documentation Committee [IKDC] score, and Lysholm Knee Scoring scale) at 3, 6 and 12 months post-operatively. Tissue ingrowth was assessed by dynamic contrast enhanced magnetic resonance imaging (DCMRI) at 3 months, and relook arthroscopy with tissue biopsy at 12 months post-implantation.

Results: 52 subjects (50 with previous meniscectomies) were enrolled. Mean age was 32.9 ±9.0, 77% were male, all stable knees (3 concomitant ACL repairs) mean defect length was 47.8 ± 10.0 mm. A significant mean improvement in knee pain on VAS and function on IKDC and Lysholm scores as well as differnent categories on KOOS were recorded at all follow-ups post-implantation. Tissue ingrowth into the device was observed on DCMRI in 37/43 (86.0%) subjects at 3 months post-implantation. Gross examination at 12 month relook arthroscopy of 45 subjects to date showed no signs of reactions to the device or its degradation products and biopsy samples from the inner free edge of the scaffold meniscus showed fully vital material, with no signs of inflammation. Similar to native meniscal tissue, three distinct layers were observed based on cellular morphology, the presence or absence of vessel structures, and ECM composition.

Conclusion: DCMRI and relook arthroscopy findings illustrate biocompatibility. Tissue ingrowth and biopsy results show potential for differentiation into meniscus-like tissue. Importantly subjects experienced significant pain relief and were able to resume normal activities. No safety concerns have been raised.

On behalf of the Actifit Study Group: R Verdonk, P Beaufils, J Bellemans, P Colombet, R Cugat, P Djian, H Laprell, P Neyret, H Paessler.