Summary
Extracorporeal shock wave therapy (ESWT) is being used to treat desmitis and tendonitis
in horses. This paper compares the clinical, ultrasonographic and histological characteristics
of ESWT treated collagenase induced superficial digital flexor tendon (SDFT) lesions,
versus untreated controls. This blinded study utilizes six mature, healthy horses
where bilateral forelimb SDFT lesions were induced. One forelimb was treated while
the other served as an untreated control. Three shock wave treatments were administered
at three week intervals. At weekly intervals, ultrasonograms were used to measure:
1) percentage lesion at the maximum injury zone (MIZ), 2) the grey scale of the SDFT
at the MIZ, 3) the percentage disruption of the longitudinal fibres at the MIZ. The
data were also summed from 8–20 cm distal to the accessory carpal bone. Measurements
of the external width of the SDFT were obtained through the study period. Examinations
were performed on four occasions to evaluate heat, response to palpation, presence/character
of swelling over the SDFT, and lameness. At the completion of the study all tendons
were evaluated histologicalally. The lesion size, grey scale, and longitudinal fibre
disruption at the MIZ, and sum of each variable changed significantly over time, however,
there was no difference between treated and control groups. Histopathology showed
increased neovascularization in treated tendons (p = 0.001). When compared to untreated
controls, ESWT did not change the ultrasonographic appearance of the tendons. However,
it did increase neovascularization.
Keywords
Superficial digital flexor tendons - tendonitis - extracorporeal shock wave therapy
- collagenase induced lesions
