Meniscal Regeneration
The best known scaffold currently available on the market is the Menaflex Collagen Meniscal Scaffold (Regen Biologics Inc, USA – sole distributors in the UK Hospital Innovations).
This is a heat moulded, shaped, collagen scaffold produced from processed bovine Achilles tendon. The scaffold is only really suitable for meniscal defects where the outer peripheral rim is still intact; the meniscal defect can then be sized, the scaffold can be cut to shape and then the implant fixed in place with multiple meniscal sutures.
Early studies have demonstrated that the Menaflex scaffold is biocompatible and that it stimulates the ingrowth of host cells and the subsequent formation of new meniscal tissue 1. The first Menaflex implantations were performed in the US in 1993, as part of a feasibility study 2. This demonstrated that at 5- to 6-year follow-up there had been an average of 69% filling of meniscal defects with new tissue. Histological evaluation showed this new tissue to consist of fibrocartilage with a uniform extracellular matrix. Patients’ pain and function scores showed significant improvement, with no evidence of progression of joint degeneration, and no adverse biological effects. These encouraging results led to large multicentre trials being established in the US and Europe, the results of which were published in 2008 3. A total of 311 patients from 26 surgeons in 16 sites were randomised into either receiving a Menaflex Collagen Meniscal Implant or undergoing a partial meniscectomy only. Patients receiving a meniscal Implant underwent second look ar-throscopy at one year. These showed that the
meniscal implants resulted in significantly increased meniscal tissue, and histological study demonstrated that the implant supported meniscus-like matrix production and integration as it was assimilated and resorbed. Patients receiving implants regained significantly more of their lost activity vs con-trols and underwent significantly fewer re-operations. Menaflex has approval for use in USA, Europe and is in clinical use in the UK in a limited number of centres.
It is perhaps in the younger patients, where loss of meniscal tissue has the greatest potential long-term consequences, that there may be the strongest indication for replacement of missing meniscal tissue with the implantation of scaffolds.
At present, however, the key to addressing the issue of meniscal injury lies in the education of surgeons performing arthroscopic surgery, emphasizing the importance of preserving functional meniscal tissue wherever possible.
Extract taken from Orthopaedic Product News August 2009
Written on behalf of Hospital Innovations Ltd
Mr Ian D McDermott, Consultant Orthopaedic Surgeon
London Bridge Hospital
Mr Angus Robertson, Consultant Orthopaedic Surgeon
Spire Cardiff Hospital