Nanofracturing: a new technique for bone marrow stimulation in equine cartilage repair

Abstract

Microfracture is the current standard in treatment of focal full-thickness cartilage lesions in horses, but clinical outcome may vary. Nanofraclure is a novel technique that uses a commercially developed device to yield smaller diomeler perforations with deeper penetration into the subchondral bone. Experimentally, in rabbits and sheep, nanofrocture has been shown to result in superior repair compared to microfracture. The objective was to study the feasibility and preliminary outcome of nanofrocture using o commercial device for treotment of cartilage defects in horses. Nonofracture was tested ex vivo in n = 2 cadaveric equine stifle joints and in vivo in n = 8 horses with experimental portiol thickness cartilage defects in the medial femoral trochlear ridge. These were treoted with an experimental biomaterial or nanofrocture, and repair tissue was studied mocroscopically (ICRS-I score) and microscopically (histological ICRS-II score ond micro-CT) ofter 7 months. Both in cadaveric equine stifle joints and in vivo, the nanofrocture device could reodily be applied and allowed easy penetration of the subchondral bone. Repoir tissue ofter 7 months was groded 'near-normal' macroscopically, while histologically, the obundant repair tissue proved mainly fibrocartilaginous in nature. Micro-CT revealed near-full restoration of mid-lesion cortilage layer thickness but oltered subchondral bone microarchitecture. The in vivo study did not include a control group treated with conventional microfracture for comparison. To our knowledge, this is the first report on bone marrow stimulation using nanofrocture as a potential method to enhance chondral defect repair in horses. In the in vivo study, no clinical odverse effects were observed, and promising good defect filling with fibrocartilaginous tissue was seen 7 months after treatment.