[Show abstract][Hide abstract] ABSTRACT: To prevent further degeneration, it is desirable to fill a meniscal defect with a supportive scaffold that mimics the mechanics of native tissue. Degradable porous scaffolds have been used, but it is unclear whether the tissue that fills the site of implantation is mechanically adequate, particularly with respect to frictional performance.
We therefore determined the frictional behavior of native and engineered meniscal replacement tissue from in vivo implantation over time.
We evaluated boundary and mixed-mode friction coefficients of tissue generated in porous polyurethane scaffolds used to augment the repair of the meniscus of 13 skeletally mature sheep after partial meniscectomy. Implants were removed for evaluation at 3, 6, and 12 months. The friction coefficient, aggregate modulus, and hydraulic permeability were evaluated for tissue harvested from native meniscus adjacent to the implants, native meniscus from the intact contralateral knee, and repair tissue from the site of the scaffold implantation. The equilibrium friction coefficient (μ(eq)) was measured in the presence of a lubricant bath of either phosphate-buffered saline (PBS) or equine synovial fluid (ESF).
Boundary μ(eq) in PBS of engineered meniscus improved with time and was similar to native tissue after 6 months. ESF enhanced lubrication for all samples at nearly all time points demonstrating the efficacy of ESF as a joint lubricant for repair tissue as well as native meniscus. Modulus increased and permeability decreased with implantation, likely as a result of tissue ingrowth.
Promoting tissue ingrowth into porous scaffolds is a potential strategy for improving friction performance in meniscal repair.
Clinical Orthopaedics and Related Research 04/2011; 469(10):2817-23. DOI:10.1007/s11999-011-1854-6 · 2.77 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: More than 1 million procedures for the total or partial removal of the meniscus are performed in the United States and Europe each year. However, it has been found that the knee can lose functionality when even small parts of the meniscus are removed, leading to degenerative changes in the joint. Healing of the medial meniscus in particular is problematic since blood vessels are present in only the outer 10–25% of the meniscus, making it desirable to preserve as much of the meniscus as possible.