Implantation of a synthetic meniscal scaffold improves joint contact mechanics in a partial meniscectomy cadaver model

Abstract

Meniscal substitutes should ideally distribute loads across adjacent articular cartilage much in the way of the native tissue, thereby protecting the cartilage from degeneration. The objective of this study was to quantify the loads transferred to the tibial plateau after implantation of a porous polyurethane scaffold. Our hypothesis was that scaffold implantation would improve the contact mechanics of a partial meniscectomy knee. Six sheep cadaver knees were mounted in a load-controlled knee-joint simulator. A pressure-sensor sheet, secured to the tibial plateau, dynamically recorded pressure data over 10 gait cycles for the following conditions: (i) intact, (ii) partial meniscectomy, (iii) implanted scaffold, and (iv) total meniscectomy. Implantation of the scaffold increased the contact area and decreased the contact pressures compared to the meniscal defect knee. No significant difference was found between the average and peak contact pressures of the intact knees and scaffold-implanted knees; however, contact area was significantly lower for the scaffold-implanted knees compared to intact knees. Our hypothesis was accepted; replacement with a polyurethane scaffold improved knee-contact mechanics relative to a partially meniscectomized knee. On the basis of these findings, the scaffold will be evaluated for its chondroprotective capacity in an in vivo ovine model.

A Pre-Clinical Test Platform for the Functional Evaluation of Scaffolds for Musculoskeletal Defects: The Meniscus

“…The sheep model was chosen because it has been previously used to evaluate meniscal repair and regeneration technology [8,9]. The mechanical properties of its meniscus are similar to that of the human meniscus and the contact stresses transmitted to the tibial plateau are within the range of that of human knees [6]. However, the tissue ingrowth that occurred in the empty meniscal defect group raises concern about the suitability of using a partial meniscectomy as a control in the ovine model.…”

“…Six ovine knees were subjected to loads and flexion-extension profiles corresponding to that experienced in the ovine knee joint during gait [30]. The effect of injury (in this case a partial meniscectomy) and repair (in this case via scaffold implantation) on the joint contact stresses transmitted to the tibial plateau were assessed [6].…”

Effect of partial meniscectomy at the medial posterior horn on tibiofemoral contact mechanics and meniscal hoop strains in human knees

“…The use of different pressure sensors for in vitro tibiofemoral contact analyses has been previously reported for canine, 18 porcine, 28 sheep, 14,29 and human knee joints. 11,12 To place the pressure sensors under the menisci, the meniscotibial coronary ligaments had to be dissected, but this has no impact on the contact mechanics under axial compression.…”

Frictional Properties of the Meniscus Improve After Scaffold-augmented Repair of Partial Meniscectomy: A Pilot Study

“…Replacing resected tissue with a support material may further improve outcome; contact area is increased and contact pressure decreased with a replacement scaffold in place when compared with a partially meniscectomized knee [3].…”

“…Specifically, polymeric materials provide a favorable cellular environment for tissue ingrowth [32] in addition to distributing load [3]. Porous polyurethane foams in particular are of interest as a meniscal replacement because the porosity of the foam scaffold facilitates tissue ingrowth [32].…”