Coffin Joint Pathology & Joint Capsule Pathology on P2

Coffin joint pathology can be difficult to detect on radiographs unless there’s significant osteophyte formation or bone erosion under the cartilage. However, pathology affecting the coffin joint capsule is often easily seen as ossifications on radiographs that form on the dorsal surface of the short pastern bone (P2) where the joint capsule attaches to it.

The objective of this survey study, conducted by Colorado State University researchers, was to determine whether the more visible signs of joint capsule pathology (called enthesopathy) can be linked to problems in the coffin joint, which can be seen using MRI but are not easily visible on radiographs.

Clinical records from an equine referral hospital over an 11-year period were used to explore the correlations present among X-ray and MRI images of 21 feet along with the results of lameness exams. Articular cartilages lesions were identified by MRI in 20 of 21 (95%) coffin joints examined, but there was no correlation between the severity of the cartilage lesions and the enthesopathy seen on radiographs.

Coffin joint synovitis and osteophytes were present in 91% and 95% (respectively) of the feet examined while collateral ligaments of the coffin joint were abnormal in 52% of limbs. 

Collateral ligament pathology was moderately correlated with coffin joint capsule enthesopathy. Lameness was present in 18 of 21 cases but was not correlated with the severity of enthesopathy or the degree of articular cartilage loss.

The authors concluded the readily visible enthesopathy seen…