2015 ISAKOS Biennial Congress ePoster #414

In Vivo Performance of a Novel Anatomically Shaped Polycarbonate Urethane Total Meniscus Replacement – A 12 Month Evaluation in Goats

Anne Vrancken, PhD, Nijmegen NETHERLANDS
Wojciech Madej, Msc, Nijmegen NETHERLANDS
Nico Verdonschot, Nijmegen NETHERLANDS
Tony Van Tienen, MD, PhD, Nijmegen NETHERLANDS
Pieter Buma, Nijmegen NETHERLANDS
Radboud University Medical Centre, Nijmegen, GLD, NETHERLANDS

FDA Status Not Applicable

Summary: The findings of this large animal study demonstrate that the in vivo performance of our novel PCU total meniscus replacement seems to be similar to allograft menisci. From this point of view the PCU implant has the potential to become an alternative treatment for total meniscectomy patients

Abstract:

Introduction

A synthetic total meniscus implant could potentially overcome the shortcomings of meniscal allografts, which are currently the only treatment option for symptomatic total meniscectomy patients. In this study, the performance of a novel, anatomically shaped, polycarbonate urethane (PCU) total medial meniscus implant was evaluated after a 12 month implantation period in goats.

Methods

26 female Saanen goats were subdivided over 4 groups: implant (I, n=7), allograft (A, n=7), meniscectomy (M, n=6) and sham surgery (S, n=6). Tibial tunnels were created in groups I and A, for suture fixation of the implant (PCU grade II 80A, DSM, the Netherlands) and allograft to the tibia plateau using a modified Revo knot. Unrestricted locomotion was allowed from 10 days post-surgery and all animals were sacrificed at 12 months follow-up. Coronal MR images were acquired immediately post-mortem, to evaluate meniscal extrusion. The articular joint surfaces were evaluated both macroscopically as microscopically. Synovium histological sections were blindly scored. To determine permanent deformation, the explanted prostheses were µCT-scanned

Results

One animal of the sham group was sacrificed preliminary because of illness unrelated to the intervention. All other animals recovered well and loaded the operated leg, without major changes to their walking pattern. Partial regeneration of the excised meniscus was seen in all animals of the meniscectomy group. Signs of mild inflammation were observed in all animals but no significant differences between groups were found. Fibrillation of the femoral and central tibial cartilage was observed for all groups, resulting in relatively high macroscopic scores. Saf-O loss in the superficial layer of the outer tibia was observed for all groups. Moderate to severe surface irregularities were found for the implant and allograft groups, while the meniscectomy group also showed fissures. All explanted prostheses showed slight lengthening and increased concavity of the central part of the femoral surface. Extrusion was highly similar for the implant and allograft groups. Both were increased compared to the sham group, but only significantly for the femoral extrusion of the allograft.

Discussion

The implant material showed good biocompatibility in the knee joint. Both implant and fixation integrity were satisfying following 1 year of physiological loading. To obtain joint congruency during the full range of flexion, the implants adapted their geometry by lengthening and concavity changes. Both the implant and allograft groups showed increased extrusion. Damage seemed to be milder than that observed in the meniscectomy group.