Arthroscopic collagen meniscus implant results at 6 to 8 years follow up

Abstract

Meniscal substitution is a fundamental procedure to prevent osteoarthritis of the knee after massive meniscectomy. Stone, Steadman and Rodkey have developed a bioreadsorbable collagen matrix (CMI) which acts as a scaffold to restore the original medial meniscal. The objective of this study was to prospectively evaluate the results of CMI implantation at a follow up from a minimum of 6 to a maximum of 8 years. Eight patients (mean age 25) were evaluated at a final observation point from 6 to 8 years after CMI implantation. Inclusion criteria were an irreparable meniscal tear or a previous meniscectomy involving the medial meniscus. Follow up evaluation included Cincinnati Knee Rating Scale (CKRS), IKDC, subjective evaluation and X-ray and MRI control. There were no complications related to the device. All patients were able to return to day activities without limitations 3 months after surgery. Both subjective CKRS score and objective IKDC score showed improvement in all cases except one patient with an ACL re-injury. In two cases scores were slightly worse from 2 years after surgery to the final observation point. The other five cases obtained maximum score at final follow-up. In four cases the absence of pain remained until the final observation point, while in four cases a low entity of pain was described at long term follow-up. MRI showed in five cases mixoid degeneration signal, two had normal signal with reduced size, while one patient had no recognizable implant. Six patients had preserved cartilage and articular space, with no changes respect to pre-op control. Arthroscopic second look evaluation has been performed in three cases, revealing in two cases the presence of the implant, although with a reduced size respect to the original one, while in one case the CMI was almost disappeared. Our small series of eight patients prospectively followed from 6 to 8 years of follow-up has shown highly satisfactory results. Although the aspect of the implant was mostly abnormal, the implant may have helped reduce the deterioration of the knee joint at final observation time.

Tissue Engineering for Total Meniscal Substitution: Animal Study in Sheep Model

“…In a dog model, the resorbable bovine collagen scaffold developed by Stone et al 40 for regeneration of meniscal tissue showed host tissue ingrowth and formation of fibrocartilage resembling a normal canine meniscus after 9 and 12 months. 12 A clinical trial concerning CMI revealed encouraging results, 10,11,13,14 but long-term, histological and MRI results are controversial and evidence of chondroprotection is still pending. In contrast to the present study, the CMI is used for partial meniscal substitution because a residual rim of the original meniscus is necessary to fix the CMI, which makes the comparison of our results difficult.…”

“…However, their long-term success, durability, safety, and chondroprotective effects are still uncertain. 8,9 The CMI (ReGen Biologics, Franklin Lakes, NJ) is the only scaffold used so far in a clinical setting, [10][11][12][13][14] even if CMI cannot be considered as total meniscal substitute as a residual rim of the original meniscus is necessary to fix the implant. Despite improvements in pain and selfevaluation, 12 the histological and magnetic resonance imaging (MRI) results remain controversial.…”

“…Despite improvements in pain and selfevaluation, 12 the histological and magnetic resonance imaging (MRI) results remain controversial. 10,13,15 Several materials have been tested as partial meniscus substitutes in animal models. Veth et al 16 used carbon fiber for meniscus repair in dogs, with unsatisfactory results.…”

Meniscus repair and regeneration: review on current methods and research potential

“…The collagen meniscus implant (CMI) (ReGen Biologics, Franklin Lakes, NJ) is the first regenerative technique applied to meniscal tissue in clinical practice (Stone et al, 1992;Stone et al, 1997;Steadman and Rodkey, 2005;Zaffagnini et al, 2007). Since an outer rim of meniscal tissue is needed for CMI implantation, it is indicated only for partial and not total meniscus regeneration.…”

Updates in biological therapies for knee injuries: menisci

“…However, these studies demonstrated the safety of the technique [23]. Zaffagnini et al [25] published a study with 8 patients with a follow-up of 6-8 years and good clinical and radiological results. However, a second-look arthroscopic assessment and magnetic resonance imaging (MRI) revealed the deterioration of the implant over time, with a considerable reduction in size or the complete degradation of the implant.…”