Identification and treatment of osteochondritis dissecans of the distal sagittal ridge of the third metacarpal bone.

The research focuses on diagnosing and treating a previously unrecorded condition called osteochondritis dissecans (OCD) in the distal sagittal ridge of the third metacarpal bone (McIII) in horses. The outcomes of the discussions are that this condition can be identified through radiographs and can be treated surgically.

Methods and Results

• The researchers decided on a retrospective case study as the methodology for this study. This involved reviewing the data of horses diagnosed with OCD in the McIII treated at a single referral center from February 2006 to February 2013.
• The condition was discovered in 16 horses who were lame (unable to walk correctly because of a leg problem). In nine horses the condition was found in one leg, while in seven it occurred in both legs.
• The lesions on the bones were identified using two types of radiographs: flexed lateromedial and dorsopalmar. Collectively, the researchers found 21 joints affected this way.
• Their surgical approach involved accessing the joints for removal of the ossified fragments and debridement (removal of damaged tissue) through the dorsal compartment with the metacarpophalangeal joints maximally flexed.

Outcomes and Follow-ups

• Follow-up data was gathered through phone interviews and by assessing the horses’ abilities to perform. In 14 horses that had a follow-up period of more than 12 months, 13 were able to perform athletically. This included 11 out of 12 Thoroughbreds that were able to race again.
• The results showed that unlike more proximal lesions, OCD in the distal sagittal ridge appears to affect the third metacarpal bone preferentially.

Conclusions and Recommendations

• The lesions could only be identified on dorsopalmar and flexed lateromedial radiographs and are amenable to arthroscopic surgery.
• The researchers concluded that clinicians should be aware of the potential for OCD to affect the distal sagittal ridge of the McIII. They need to have knowledge of the radiographic projections necessary to identify the presence of this condition.
• The researchers also recommend a modified arthroscopic approach in order to access the dorsal metacarpophalangeal joint for the removal of lesions.