Surgical osteochondral defect repair in the horse-a matter of form or function?

Maria C Fugazzola,Paul R Van Weeren

doi:10.1111/evj.13231

Abstract

Focal cartilaginous and osteochondral lesions can have traumatic or chondropathic degenerative origin. The fibrocartilaginous repair tissue that forms naturally, eventually undergoes fibrillation and degeneration leading to further disruption of joint homeostasis. Both types of lesion will therefore eventually lead to activity‐related pain, swelling and decreased mobility and will frequently progress to osteoarthritis. Most attempts at realising cartilage regeneration have so far resulted in cartilage repair (and not regeneration). The aim of this article was to review experimental research on surgical cartilage restoration techniques performed so far in equine models. Currently available surgical options for treatment of osteochondral lesions in the horse are summarised. The experimental validity of equine experimental models is addressed and finally possible avenues for further research are discussed.

Highlights

Focal cartilaginous and osteochondral lesions can have traumatic or chondropathic degenerative origin
Both types of lesion will lead to activity-related pain, joint effusion and decreased mobility, frequently progressing to osteoarthritis.[2]
If not all, attempts at realising cartilage regeneration have so far resulted in cartilage repair, not far from what endogenous repair would achieve in a joint

Summary

| INTRODUCTION

Focal cartilaginous and osteochondral lesions can have traumatic or chondropathic degenerative origin. Regeneration refers to healing in which there is regrowth of tissue towards the original, normal state. Compared to other animal models, articular cartilage thickness and subchondral bone thickness in the stifle of adult horses most closely approximates that of the human knee[5,6] (Figure 1). Because defects of relatively large size can be made experimentally in the horse, more outcome parameters (arthroscopic re-evaluation, histological assessment, biomechanical testing, diagnostic imaging, biochemical analysis) can be measured with each repair response than is possible in other animal models.[7] Based on two fundamental studies on spontaneous cartilage healing of experimental lesions in the equine stifle, the clinically relevant size for created osteochondral lesions has been determined to be 9 mm in diameter.[8,9] In the medial femoral

Lateral Medial

Cement line Subchondral bone plate

Findings

Calcified cartilage Subchondral bone plate