The role of computed tomography in evaluation of subchondral osseous lesions in seven horses with chronic synovitis

Abstract

Summary Seven horses with severe, persistent lameness of sudden onset were evaluated with scintigraphy and/or computed tomography. The lameness was localised to the front fetlock joint in 2 horses and to the tibiotarsal joint in 5 horses. Five of the horses had a history of intra‐articular injections of the involved joint prior to presentation. All horses had effusion of the affected joint and were positive to flexion tests. Intraarticular anaesthesia eliminated or improved the lameness in 4 cases and a nerve conduction block proximal to the affected joint improved the lameness in another. Cytology examination of fluid from affected joints identified normal joint fluid (one horse) or elevations in nucleated cell counts of 0.9 × 109/1–36.8 × 109/l and total protein 20–42 g/l (6 horses). The joint fluid of 2 of these horses cultured positive for bacteria. Initial radiographs were either normal (4 cases) or the changes seen were not sufficient to explain the degree of lameness. In the 6 cases where scintigraphy was performed, intense focal isotope uptake was found in the suspected region, which corresponded to the proximal portion of the first phalanx (2 cases), distal tibia (2 cases), or talus (3 cases). Computed tomography (CT) was performed because occult fracture or osteomyelitis was suspected; and knowledge of the precise anatomical location of the lesion was considered necessary to assess the need for surgery and to plan the surgical approach. Hypodense focal lesions with hyperdense haloes were found in the subchondral bone deep to the sagittal groove of the first phalanx (P1) (2 cases) in the cochlea of the distal tibia (2 cases), and in the intertrochlear portion of the talus (3 cases). Communication between the lesion and the joint space was demonstrated by CT in 5 cases. Post mortem examination of one case revealed synovitis and a chronic bone abscess (Brodie's abscess) communicating with the joint space.

Osseous cyst-like lesions/subchondral bone cysts of the phalanges

“…Trauma has been implicated as OCLLs have been recognised after articular sepsis (Hance et al . 1993; Hanson et al . 1996; Garcia‐Lopez and Kirker‐Head 2004), osteoarthritis (von Rechenberg et al .…”

“…1982). Proximal axial proximal phalangeal OCLLs have also been noted and are frequently identified just distal to the sagittal groove (Hanson et al . 1996; Dyson and Murray 2006).…”

“…Perineural analgesia at the level of the palmar/ plantar digital nerves is often not effective in completely removing the signs of lameness from horses even with distal phalangeal OCLLs; however, perineural analgesia at the abaxial sesamoid level, should alleviate the lameness (Trotter and Dyson 2003). Intra‐articular analgesia will often improve the lameness if the OCLL communicates with the joint (Trotter and Dyson 2003); however, it will often not completely abolish the lameness (Hanson et al . 1996).…”

Computed tomography of the stifle region in the horse: a comparison with radiographic, ultrasonographic and arthroscopic evaluation

“…Sie wird hier als Nativ- (Manco et al, 1986;Passariello et al, 1 983) oder Kontrastuntersuchung (Ghelman, 1 985; Schuler et al, 79BZ) eingesetzt und erwies sich in einer arthroskopisch kontrollierten Studie als sehr zuverlässig (Jerosch et al, 1991). lm Bereich der Pferdeorthopädie ist die Computertomographie ein relativ neues Verfahren, konnte inzwischen jedoch bei verschiedenen klinischen Fragestellungen zusätzliche lnformationen beisteuern (Hanson et al, 1996;O'Callaghan, 1991;Tietje, 1994Tietje, und 1997Wisner et al, 7997). Bisher liegen allerdings noch keine Berichte über den Einsatz am Kniegelenk vor.…”

Iontophoresis of dexamethasone‐phosphate into the equine tibiotarsal joint

“…Recently, dexamethasone‐phosphate iontophoresis has been introduced into veterinary medicine. Intra‐articular iontophoresis of pharmacologic agents in veterinary medicine would potentially avoid the occurrence of bacterial contamination following intra‐articular injection (Hanson et al , 1996). However, evidence of the basic pharmacokinetics of dexamethasone‐phosphate iontophoresis using parameters from current clinical practice remains undocumented.…”