Arthroscopic findings in horses with subtle radiographic evidence of osteochondral lesions of the medial femoral condyle: 15 cases (1995-2002).

This study investigates how subtle changes in X-ray results might point to bone and cartilage damage in the knees of horses showing lameness. They found that even minor signs in the X-rays were likely to indicate visible damage when examined through arthroscopy.

Objective of the Research

• The primary purpose of this research was to understand what arthroscopic findings might be present in horses that were lame and had subtle radiographic signs of osteochondral lesions (damage to both bone and cartilage) in the medial femoral condyle (part of the horse’s knee).

Research Methodology

• The research was conducted retrospectively, meaning previous patient data was analyzed rather than setting up new cases for study purposes.
• Researchers studied medical records of 15 horses that had been brought in for lameness and had showed subtle signs of osteochondral lesions on radiographics. Their physical examination results, radiography and arthroscopy results were recorded. Follow-up information on these horses was collected through reexamination or conversations with the referring veterinarians, owners, or trainers.

Results of the Research

• Severity of lameness in the horses ranged between grades 1 to 3 (on a scale of 0 to 5).
• Both radiography and arthroscopy were performed on 28 stifle joints. The four unaffected joints in four horses that were lame on one side and underwent bilateral arthroscopy did not show any radiographic lesions. However, two out of these four did show arthroscopic lesions.
• 20 out of the remaining 24 joints showed signs of the apex of the medial femoral condyle getting flatter, while 4 had minimal subchondral lucency (suggesting a possible loss of bone density underneath the cartilage).
• Arthroscopy revealed lesions in 18 joints where condyle flattening was seen and in all 4 joints with subchondral lucency.
• The horses were treated with abrasion arthroplasty or microfracture. At follow-up, 7 out of the 9 horses with localized cartilage lesions and 2 of the 6 horses with generalized cartilage lesions appeared to be sound with no signs of joint effusion (fluid accumulation).

Conclusions

• The study concludes that horses showing hind limb lameness and subtle radiographic signs of lesions on the medial femoral condyle are likely to have visible cartilage lesions and subchondral bone defects upon arthroscopic examination.