Arthroscopic diagnosis and treatment of intra-articular insertional injuries of the suspensory ligament branches in 18 horses

Abstract

Reasons for performing study: Clinical association between the branches of insertion of the suspensory ligament (SL) and metacarpophalangeal (MCP) and metatarsophalangeal (MTP) joints has been reported. However, there has been no assessment of the lengths of the SL branches which are subsynovial with respect to the joints or reports of involvement of the MCP/MTP joints in injuries of the SL branches.

Objectives: To establish proportions of SL branches subsynovial with respect to the MCP/MTP joints and report clinical and arthroscopic findings in horses with desmitis of SL branches identified as having an articular component to the lesion.

Hypothesis: Arthroscopic surgery enables identification and potential treatment of intra-articular injuries of SL branches.

Methods: Twelve forelimbs and 13 hindlimbs were dissected and the total and subsynovial lengths of the SL branches recorded. Case records of horses with intra-articular injuries of the SL branches were reviewed and 18 animals identified. Diagnostic information and arthroscopic findings were recorded and results of treatment determined by telephone follow-up.

Results: Of SL branches, 28.45% in the forelimb and 29.56% in the hindlimb were subsynovial to the MCP and MTP joints. All animals with intra-articular lesions of the SL branch were lame and had distension of the affected MCP/MTP joint. In 16 horses (17/22 branches), there was palpable thickening of the affected SL branch. Disrupted infrastructure was evident ultrasonographically in 15/17 branches and involvement of the dorsal articular surface of the ligament was predicted in 12/17 branches. Following arthroscopic intervention, 13 horses returned to work at a level equal to or greater than that achieved prior to injury and 2 returned to work at a lower level. Three horses incurred separate injuries and were retired or subjected to euthanasia.

Conclusions: Articular involvement should be considered in animals with injuries of an SL branch and concurrent distension of the MCP/MTP joint. Arthroscopy is necessary to identify such lesions confidently and to direct case management.

Potential relevance: Arthroscopy of the MCP/MTP joints can make a positive contribution to the assessment and management of some SL branch injuries.