Objective—To determine clinical characteristics of
and outcome in Thoroughbred racehorses with tibial
or humeral stress fractures.
Animals—99 Thoroughbreds with tibial or humeral
Procedure—Information obtained from the medical
records included history, signalment, and clinical, radiographic,
and scintigraphic findings. Outcome was
determined by interviewing trainers, performing follow-
up examinations, and analyzing race records.
Results—Seventy-four tibial stress fractures were
identified in 61 Thoroughbreds, and 48 humeral
stress fractures were identified in 39 Thoroughbreds
(1 horse was included in both groups). Tibial stress
fractures occurred most commonly in 2-year-old or
unraced horses. Fractures were located in 1 of 3 sites
in the tibia (most commonly, the caudolateral cortex
of the mid-diaphysis) and 1 of 4 sites in the humerus
(most commonly, the caudodistal cortex). Forty-four
of 58 (76%) tibial stress fractures and 18 of 32 (56%)
humeral stress fractures were identified radiographically.
Humeral stress fractures involving the caudodistal
cortex were not detected radiographically.
Treatment consisted of rest and exercise restriction,
and 49 of 61 (80%) horses with tibial stress fractures
and 30 of 39 (77%) horses with humeral stress fractures
returned to racing. Humeral stress fractures
recurred in 6 horses.
Conclusions and Clinical Relevance—Results suggested
that in Thoroughbred racehorses, tibial stress fractures
occurred most commonly in unraced 2 year olds, whereas
humeral fractures occurred most commonly in older
horses that had raced previously. The prognosis for racing
following treatment was good. (J Am Vet Med Assoc
To determine the effect of a mobile UV-C disinfection device on the environmental bacterial bioburden in veterinary facilities.
40 swab samples of surfaces from the operating theaters of 3 veterinary hospitals and 1 necropsy laboratory.
Various surfaces were swabbed, and collected material was eluted from the swabs in PBSS. Then, an aliquot of the sample fluid was processed with a bacteria-specific rapid metabolic assay to quantify bacterial bioburden. Each site was then treated with UV-C light with an automated disinfection device for approximately 45 minutes. The same surfaces were swabbed following UV-C treatment, and bioburden was quantified. The bioburden at additional time points, including after a second UV-C treatment, was determined for the small animal operating theater.
All surfaces at all sites had a persistent viable bacterial population following manual cleaning. Disinfection with UV-C achieved a mean bioburden reduction of 94% (SD, 5.2%; range, 91% to 95%) for all surfaces, compared with manual disinfection alone. Repeated UV-C treatment of the small animal operating theater reduced mean bioburden by 99% (SD, 0.8%), including no detectable bacteria on 4 of 10 surfaces.
CONCLUSIONS AND CLINICAL RELEVANCE
Disinfection with UV-C light may be a beneficial adjunct method for terminal disinfection of veterinary operating theaters to reduce environmental bioburden.
Objective—To investigate the effect of laser shock
peening on the fatigue life and surface characteristics
of 3.5-mm-diameter cortical bone screws.
Sample Population—32 stainless steel, 3.5-mm-diameter
cortical bone screws.
Procedure—Screws were randomly assigned to an
untreated control group or 2 power-density treatment
groups, 6 gigawatts (GW)/cm2 and 8.5 GW/cm2, for laser
shock peening. Number of cycles to failure and findings
on scanning electron microscopy-assisted morphometric
evaluation, including the mode of failure, surface
debris, surface damage, and thread deformation, were
compared between control and treated screws.
Results—The 6 GW/cm2 treated screws had a significant
(11%) improvement in fatigue life, compared
with untreated control screws. The 8.5 GW/cm2 treated
screws had a significant (20%) decrease in fatigue
life, compared with control screws. A mild but significant
increase in thread deformation was evident in all
treated screws, compared with control screws. The
8.5 GW/cm2 treated screws had significantly more
surface irregularities (elevations and pits), compared
with control or 6 GW/cm2 treated screws.
Conclusions and Clinical Relevance—A modest positive
increase in fatigue strength was produced by this
design of laser shock peening on the midshaft of cortical
bone screws. High laser shock peening power densities
were detrimental, decreasing screw fatigue strength
probably resulting from structural damage. Greater
fatigue life of cortical bone screws can be generated
with laser shock peening and could reduce screw breakage
as a cause of implant failure; however, future studies
will be necessary to address biocompatibility, alternative
cleaning techniques, alterations in screw strength
and pullout characteristics, and effects on susceptibility
to corrosion. ( Am J Vet Res 2004;65:972–976)