Objective—To determine the effect of limb positioning on the radiographic appearance of the distal and proximal interphalangeal joint spaces of the forelimbs of horses during evaluation of dorsopalmar radiographs.
Animals—14 forelimbs from 9 adult horses.
Procedures—Each horse was in standing position with its forelimbs positioned on blocks. Dorsopalmar radiographs of each foot were obtained with the forelimbs positioned squarely (the metacarpus of both forelimbs was perpendicular to the ground as determined by visual examination [abducted 0°]; baseline) and abducted 5° and 10°. The width of the space at the medial and lateral aspects of the distal and proximal interphalangeal joints (medial and lateral joint space width, respectively) was measured. Mediolateral joint balance was calculated as the difference between the widths of the lateral and medial joint spaces, and joint space width and mediolateral joint balance were compared among all 3 positions.
Results—As the extent of limb abduction increased, the medial aspect of the proximal and distal interphalangeal joints became narrower, compared with the corresponding lateral aspect of those joints. For both the distal and proximal interphalangeal joints, the mediolateral joint balance differed significantly among all limb positions.
Conclusions and Clinical Relevance—Forelimb position significantly affected the mediolateral joint balance of the interphalangeal joints of horses. Thus, it is crucial that the forelimbs of horses be squarely positioned when dorsopalmar radiographs are obtained for accurate evaluation of interphalangeal joint space and balance.
Objective—To evaluate the sedative and analgesic effects of subanesthetic doses of ketamine in horses sedated with xylazine, with or without butorphanol.
Design—Prospective, randomized, controlled study.
Animals—10 adult horses.
Procedures—Each horse was sedated multiple times by administration of xylazine (treatment X), xylazine and butorphanol (treatment XB), xylazine with 1 of 2 dosages of ketamine (treatment XK1 or XK2), or xylazine and butorphanol with 1 of 2 dosages of ketamine (treatment XBK1 or XBK2). Head height and various behaviors, including responses to noise, insertion of a dental float, needle prick on the flank, algometer pressure on the scapula, and bilateral carpal arthrocenteses, were evaluated.
Results—No significant differences were detected among sedation treatments for head height, response to noise, or response to arthrocenteses. Insertion of a dental float was easiest with treatment XBK2 and most difficult with treatments XK1 and XK2. Response to a needle prick on the flank was lowest with treatment XB and highest with treatment XK2. Tolerance to algometer pressure over the scapula was highest with treatment XBK2 and lowest with treatment X.
Conclusions and Clinical Relevance—Administration of a subanesthetic dosage of ketamine with xylazine and butorphanol may facilitate certain procedures, such as insertion of a dental float, in horses and enhance tolerance to pressure stimulation, but it may worsen responses to acute pain, such as that caused by a needle prick. Further evaluation is needed to determine whether subanesthetic dosages of ketamine might be useful when performing certain clinical procedures in horses.
OBJECTIVE To investigate potential associations between repository radiographic findings and subsequent performance of Quarter Horses competing in cutting events.
DESIGN Retrospective cohort study.
SAMPLE Repository radiographs (ie, radiographs obtained at the time of sale) for 343 client-owned horses.
PROCEDURES Repository radiographic findings were compared with objective measures of performance, including the likelihood of competing; the likelihood of earning money as a 3-year-old, as a 4-year-old, and as a 3- and 4-year-old combined; and the amount of money earned as a 3-year-old, as a 4-year-old, and as a 3- and 4-year-old combined.
RESULTS The presence of mild osteophytes involving the distal aspect of the tarsal joint was significantly associated with lower mean earnings as a 4-year-old. The presence of osteophytes on the dorsoproximal aspect of the middle phalanx of the hind limbs was significantly associated with an increased odds of earning money as a 4-year-old. Radiographic lesions of the medial femoral condyle of the stifle joint were not significantly associated with subsequent performance.
CONCLUSIONS AND CLINICAL RELEVANCE Most abnormalities identified on repository radiographs were not significantly associated with subsequent performance. The significant association between mild tarsal osteophytosis and earnings was unexpected. Results of the present study indicated the need for further investigation of the relationship between radiographic findings and performance outcome in Western performance horses.
CASE DESCRIPTION A 12-year-old mixed-breed mare (horse 1) and 6-year-old Friesian gelding (horse 2) were examined for chronic lameness associated with the stifle joint.
CLINICAL FINDINGS Lameness examination revealed effusion of the right (horse 1) or left (horse 2) femoropatellar and medial femorotibial joints and grade 3/5 (horse 1) or 4/5 (horse 2) lameness. A diagnosis of cranial cruciate ligament (CCL) injury with associated mineralization and avulsion (horse 1) or mineralization alone (horse 2) was facilitated in both horses with a caudomedial-craniolateral oblique radiographic view obtained 45° medial to the caudocranial line, which highlighted the origin of the ligament on the caudoaxial aspect of the lateral femoral condyle within the intercondylar fossa. These lesions were subsequently confirmed via CT.
TREATMENT AND OUTCOME Arthroscopy of the medial and lateral femorotibial joints was performed for horse 1 and revealed the osseous fragment associated with the CCL, but the fragment could not be removed. Horse 2 was euthanized while anesthetized following CT owing to the poor prognosis.
CONCLUSIONS AND CLINICAL RELEVANCE Radiography is typically the first imaging modality attempted for horses with CCL injury, particularly outside the hospital setting. A 45° caudomedial-craniolateral oblique radiographic view may aid in diagnosis of CCL injury when avulsion or mineralization is present. Although this view is not commonly included in the typical radiographic series for imaging of the stifle joint in horses, it should be considered when CCL injury is suspected.