Changes in articular cartilage after meniscectomy and meniscus replacement using a biodegradable porous polymer implant

Abstract

PurposeTo evaluate the long-term effects of implantation of a biodegradable polymer meniscus implant on articular cartilage degeneration and compare this to articular cartilage degeneration after meniscectomy.MethodsPorous polymer polycaprolacton-based polyurethane meniscus implants were implanted for 6 or 24 months in the lateral compartment of Beagle dog knees. Contralateral knees were meniscectomized, or left intact and served as controls. Articular cartilage degeneration was evaluated in detail using India ink staining, routine histology, immunochemistry for denatured (Col2-¾M) and cleaved (Col2-¾Cshort) type II collagen, Mankin’s grading system, and cartilage thickness measurements.ResultsHistologically, fibrillation and substantial immunohistochemical staining for both denatured and cleaved type II collagen were found in all three treatment groups. The cartilage of the three groups showed identical degradation patterns. In the 24 months implant group, degradation appeared to be more severe when compared to the 6 months implant group and meniscectomy group. Significantly more cartilage damage (India ink staining, Mankin’s grading system, and cartilage thickness measurements) was found in the 24 months implant group compared to the 6 months implant group and meniscectomy group.ConclusionDegradation of the cartilage matrix was the result of both mechanical overloading as well as localized cell-mediated degradation. The degeneration patterns were highly variable between animals. Clinical application of a porous polymer implant for total meniscus replacement is not supported by this study.

Fatigue life of bovine meniscus under longitudinal and transverse tensile loading

“…An obstacle in the development of functional meniscus implants has been fatigue failure during long duration animal studies. 33, 34 To improve fatigue properties, researchers have begun to evaluate fatigue life of synthetic soft-tissue analogs, typically under compressive loading. 35, 36 The present study will allow research groups to directly compare the tensile fatigue properties of their replacement devices to the tensile fatigue properties of native meniscus.…”

Animal Models of Meniscal Injury in Post-Traumatic Arthritis

“…In the dog, at 3-6 months after total lateral meniscectomy, no signs of synovial infl ammation are evident, tibial OA lesions are diffuse and more severe than the femoral lesions which are localized to the posterior curvature of the condyle [ 118 ]. By 2 years postoperatively, a well-defi ned fi brous structure containing some degree of collagen organization, type II collagen and s-GAG deposition [ 119 ] is present in the original location of the meniscus, but is not protective against lateral compartment PTA which is worse and more diffuse on the tibia compared to the femur [ 120 ]. Thus, in the dog, PTA after lateral meniscectomy may progress more slowly than after medial meniscectomy.…”

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

“…Following several experimental studies in animal models for total meniscus replacement (van Tienen et al, 2009;Welsing et al, 2008;Hannink et al, 2011), polyurethanes are now being assessed as alternative biomaterials for partial meniscus replacement. The Actifit™ (Actifit, Orteq Ltd, London, United Kingdom) meniscus implant is a polyurethane-polycaprolactone (PU-PCL)-based synthetic meniscal substitute intended for use in the irreparable, partial meniscal defects Verdonk et al, 2011).…”

“…The results of an orthotopic study in dogs with a 6-month and 2-year follow up have been reported (Welsing et al, 2008;Hannink et al, 2011). In this study, they compared the outcome of total meniscectomy with that of the implant of a PU-PCL total meniscal implant.…”