Experiences with Osteochondral Weight-Bearing Joint Surface Replacement in Horses

Author: Gábor Bodó
Year: 2017

1. Introduction and Objectives

Over the last two decades, joint surface reconstruction techniques have come to the forefront of human orthopedic surgery. Joint surface conditions in humans show several similarities to those in horses.

In 2001, the author defended a PhD thesis on autogenous osteochondral transplantation in horses. This current work continues from that, summarizing further experimental and clinical experiences.

Inspired by Prof. László Hangody, who pioneered the mosaicplasty technique for cartilage defects, the author aimed to adapt this method for use in horses. Since then, the technique has been applied and studied both experimentally and clinically in equine patients.

Hyaline cartilage in humans and mature animals does not regenerate effectively. Damage typically leads to fibrocartilage repair, which is biomechanically inferior and often leads to osteoarthritis.

The horse is not only a companion and athlete but also an economically significant species in many European countries. Its cartilage structure is also most comparable to human cartilage among various animal models, making findings in equine studies particularly valuable for human medicine.

The objective of this doctoral work is to summarize 15 years of clinical and experimental experience using mosaicplasty in horses, specifically for reconstructing weight-bearing surfaces of the fetlock and stifle joints.

2. New Scientific Findings

1. Optimal Graft Harvest Site:
   For 8.5 mm grafts, the proximal medial femoral trochlea is the ideal donor site due to better healing and less surface damage.

2. Collagen Fiber Orientation:
   Variations in collagen fiber direction in surface cartilage do not significantly affect transplant success. Perfect graft fit and careful surgical technique are more crucial.

3. Joint Homeostasis Recovery:
   After mosaicplasty in the medial femoral condyle, joint homeostasis in horses returns within two weeks, based on synovial fluid biomarkers. This level of sensitive analysis had not been previously done in horses or humans.

4. Age-Related Success Rate:
   Horses under 7 years showed a 92% success rate in regaining activity post-surgery. In horses older than 7, the success rate dropped to 25%, highlighting the need for alternative treatments in older horses.

5. Subchondral Bone Cysts:
   The author recommends drilling a central 8.5 mm hole into the cyst to facilitate full curettage and strategic graft placement. This allows for better control and fewer grafts needed.

6. Postoperative Arthroscopic Control:
   A follow-up arthroscopy 4–6 months post-surgery is advised (especially for 8.5 mm grafts) to smooth irregularities and remove frayed tissue.

7. Improved Surgical Closure:
   A five-layer wound closure technique (joint capsule, deep and superficial fascia, subcutis, and skin) reduces complications compared to previously used three- or four-layer methods.