High intraosseous pressure as a cause of lameness in a horse with a degloving injury of the metatarsus.
A 6-year-old Paint mare undergoing treatment for a degloving injury of the right metatarsus developed a non-weight-bearing lameness 19 days after admission. Diagnostic nerve blocks localized the source of pain to the area between the tarsus and the metatarsophalangeal joint. Radiography of the metatarsus and metatarsophalangeal joint, arthrocentesis of the metatarsophalangeal joint, and ultrasonography of the flexor tendons, flexor tendon sheath, and suspensory ligament failed to identify the cause of the lameness. The horse was anesthetized and intraosseous pressure was measured in the left and right third metatarsal bones, using a self-tapping cannulated screw attached to a pressure transducer. Pressure in the affected limb (46 mm Hg) was 3.5 times as high as pressure in the unaffected limb (13 mm Hg). The day after pressures were measured and fenestration was performed, signs of lameness were substantially improved. High intraosseous pressure in the affected limb was most likely secondary to edema, inflammation, and partial venous thrombosis, in combination with bone neovascularization, that impaired intraosseous venous drainage from the medullary cavity. Fenestration of the affected bone relieved the excessive pressure and allowed for resolution of pain.
Morisset
S
S
Department of Veterinary Clinical Sciences, Purdue University, West Lafayette, IN 47907-1248, USA.
Hawkins
J F
JF
Kooreman
K
K
D000818:Animals; D005260:Female; D006736:Horses / Q000293:injuries*; D007794:Lameness, Animal / Q000209:etiology* / Q000601:surgery; D008682:Metatarsal Bones / Q000293:injuries* / Q000503:physiopathology / Q000601:surgery; D010146:Pain / Q000209:etiology / Q000662:veterinary; D010521:Periosteum / Q000293:injuries; D011312:Pressure; D013524:Surgical Flaps / Q000662:veterinary; D013708:Tendon Injuries / Q000503:physiopathology / Q000662:veterinary