Landing impact loads predispose osteocartilage to degeneration

Abstract

Knee osteoarthritis is a prevalent disease worldwide and is characterized by progressive degeneration in structure and functionality of the articular cartilage. While it is widely suggested that activities involving large landing impact loads may lead to post-traumatic osteoarthritis, there is little understanding on whether these loads can inflict cartilage lesions and trigger degeneration. This study sought to investigate whether landing impact loads applied to the osteocartilage will render it towards degeneration. Menisci-covered and exposed osteochondral explants were extracted from tibial cartilage of fresh porcine hind legs and placed in culture for up to 14 days. A single 10-Hz haversine impact compression was performed at Day 1. Control (non-impact) and impacted explants were randomly selected for cell viability, glycoaminoglycan and collagen content assessment, histology, immunohistochemistry and micro-computed-tomography. When 2-mm displacement compression was applied, exposed explants attained a considerably greater peak impact stress than meniscicovered explants. There was no observable difference in cell viability, glycoaminoglycan and collagen content, and Mankin scores between menisci-covered and exposed explant groups. Both groups were noted with diminished proteoglycan and type II collagen staining at Day 14; the exposed group indicated increased cartilage volume at Day 7- 14. Large landing impact loads can introduce structural damage to the osteocartilage, which leads to osteoarthritis-like degenerative changes. The inferior resilience of menisci-covered regions, against impact-induced damage and degeneration, may be a key factor involved in the meniscectomy model of osteoarthritis.