Increased cartilage oligomeric matrix protein concentrations in equine digital flexor tendon sheath synovial fluid predicts intrathecal tendon damage.

OBJECTIVES: To evaluate digital flexor tendon sheath (DFTS) synovial fluid cartilage oligomeric matrix protein (COMP) concentrations as a molecular marker for intrathecal pathology. STUDY DESIGN: Case control study. ANIMALS: Horses (n=46) with DFTS tenosynovitis; 23 fresh cadaver horses. METHODS: DFTS synovial fluid samples were collected from clinical cases with noninfected DFTS tenosynovitis and from control DFTS. Clinical and surgical findings were recorded, and dissection of control limbs was performed to confirm the DFTS to be grossly normal. Synovial fluid COMP was quantified using a homologous competitive inhibition ELISA. RESULTS: Abnormalities were identified tenoscopically: intrathecal tendon/ligament tearing was identified in 37 cases and 9 had other lesions. In control horses, synovial fluid COMP was higher in younger horses. Clinical cases with intrathecal tendon/ligament tearing had higher synovial fluid COMP than either clinical cases with other lesions, or controls. In horses ≥5 years old, the sensitivity and specificity of the assay was high for diagnosing intrathecal tendon/ligament tearing. CONCLUSIONS: COMP concentrations in DFTS synovial fluid were significantly greater than those in normal horses with noninfected tenosynovitis caused by intrathecal tendon/ligament tearing, but not by other lesions.

Arthroscopic evaluation of the metacarpophalangeal and metatarsophalangeal joints in horses with parasagittal fractures of the proximal phalanx.

BACKGROUND: Fractures of the proximal phalanx are one of the most common long bone fractures of Thoroughbred racehorses. Although the degree of disruption and damage to the articular surface is generally considered a major prognostic determinant, associated arthroscopic findings have not previously been reported. OBJECTIVES: To describe the metacarpo/metatarsophalangeal (MCP/MTP) joint lesions associated with parasagittal fractures of the proximal phalanx arthroscopically identified at the time of fracture repair and compare radiographic and arthroscopic appearance of complete fractures. STUDY DESIGN: Retrospective case series. METHODS: Case records and arthroscopic images of horses with parasagittal fractures of the proximal phalanx admitted to Newmarket Equine Hospital from 2007 to 2017 were analysed. RESULTS: 81 MCP/MTP joints in 78 horses underwent arthroscopic evaluation concurrent to parasagittal fracture repair. Tears of the joint capsule and dorsal synovial plica were noted in 43 cases. Arthroscopy identified articular incongruity in three horses where fracture displacement was not predicted at all on pre-operative radiographs, and incongruity in additional plane(s) to the radiographic displacement in 14 horses. Concurrent osteochondral fragmentation and disruption of cartilage were present in some cases. MAIN LIMITATIONS: As a retrospective study, the arthroscopic data available for review were variable. Arthroscopic assessment of fracture reduction and joint congruency was evaluated in all cases but there was variation in the completeness of evaluation of the entire dorsal joint space of the fetlock joint. This may have led to the underestimation of soft tissue lesions in these cases. CONCLUSIONS: Some horses suffering from parasagittal proximal phalanx fractures have concurrent tearing of the joint capsule and/or dorsal plica, which may have relevance in the acute course of events resulting in the development of fractures. Fracture displacement and incongruency at the articular surface cannot confidently be excluded pre-operatively by radiographs alone.

A lateral approach to the repair of propagating fractures of the medial condyle of the third metacarpal and metatarsal bone in 18 racehorses.

OBJECTIVES: To report the technique, observations on fracture configurations and results of treatment by fixation lag screw following the fracture plane determined by an approach to the third metacarpal/metatarsal bone (MC3/MT3) that begins laterally over the metacarpo(metatarso)phalangeal joint and extends dorsally over the diaphysis of the bone. STUDY DESIGN: Case series. ANIMALS: Thoroughbred horses (n=18) with propagating fractures of the medial condyle of MC3/MT3. METHODS: Retrospective analysis of case records of horses with fractures of the medial condyle of MC3/MT3 that propagated sagittaly or in a spiral configuration into the diaphysis, repaired surgically under general anesthesia by screw fixation in lag fashion through a lateral approach with periosteal reflection. RESULTS: Fractures were readily identified at surgery, enabling screw fixation in lag fashion following the fracture plane. Fracture configurations varied and could be classified as sagittal and spiral fractures with fractures within each group generally following a similar course. All horses recovered relatively uneventfully from general anesthesia and surgery, and all fractures healed well. Thirteen horses returned to training; 5 subsequently raced. CONCLUSIONS: Repair of propagating sagittal and spiral fractures of the medial condyle of MC3/MT3 with diaphyseal involvement, through a lateral approach with periosteal reflection permits stable fixation with minimal complications. In this series there were no catastrophic failures. CLINICAL RELEVANCE: Fractures of the medial condyle of MC3/MT3 that propagate either sagittaly or in a spiral configuration into the diaphysis can be successfully repaired with screw fixation in lag fashion using a lateral approach with periosteal reflection.