Feline Ilial Fractures: A Prospective Study of Dorsal Plating and Comparison with Lateral Plating

Objective— To (1) report a technique for repair of feline ilial fractures using a dorsally applied bone plate and (2) compare outcome with cats treated by a lateral plate.
Study Design— Prospective study.
Animals— Cats (n=10) with iliac fractures.
Methods— Cats with ilial fractures (January 2005–December 2006) were treated by application of a dorsally applied bone plate. Immediate postoperative radiographs were compared with those taken 4–6 weeks later to assess screw loosening, screw purchase, and pelvic canal narrowing. Owners were contacted for medium-term (>3 month) follow-up. Data were compared with a report of outcome after lateral plating (LP) in 21 cats.
Results— Mean (± SD) screw purchase (89 ± 11 mm) was significantly greater ( P <.01) with a dorsal plate compared with a lateral plate (33 ± 8 mm). Significantly more screws ( P <.01) were used with a dorsal plate (median, 7) compared with a lateral plate (median, 6). Significantly less postoperative pelvic canal narrowing developed in the dorsal plating group between postoperative and 4–6-week follow-up radiography compared with the LP group (2% versus 15%, P <.01).
Conclusion— Dorsal plating of feline ilial fractures results in significantly less screw loosening and pelvic canal narrowing at 4–6 weeks after surgery compared with LP.
Clinical Relevance— Dorsal plating of feline iliac fractures may reduce complications associated with pelvic canal narrowing such as constipation and megacolon.     

Biomechanical Comparison of Two Alternative Tibial Plateau Leveling Osteotomy Plates with the Original Standard in an Axially Loaded Gap Model: An In Vitro Study

Objective— To compare the axial compression stiffness of osteotomized canine tibiae stabilized with Slocum, Securos, or Synthes plates after a tibial plateau leveling osteotomy (TPLO) procedure. Study Design— In vitro, paired comparison of cadaveric tibial constructs subjected to mechanical testing under an axial load. Sample Population— Canine tibiae (n=16 pairs) from skeletally mature male and female dogs of various breeds (18–55 kg). Methods— Tibial pairs (n=16) were randomly assigned to 1 of 2 study cohorts (n=8 pairs/cohort): cohort 1, tibial osteotomy stabilization with a Slocum or a Securos plate, or cohort 2, tibial osteotomy stabilization with a Slocum or a Synthes plate. One tibia from each pair was stabilized with 1 of each plate design assigned to the cohort after TPLO. A 3.2 mm osteotomy gap was maintained during plate application in all constructs. Load and axial displacement were recorded while constructs were loaded to 2000 N in axial compression. Failure loads were not reported because no distinct yield point or failure point was evident within the load range for many specimens. Failure modes were recorded for each construct, and photographs of typical failures were obtained. Stiffness (N/mm) was calculated from load–displacement curves. Paired comparisons of mean stiffness were performed within study groups using a paired t‐test. Significance was set at P<.05. Results— The mean construct stiffnesses for the Slocum (383±183 N/mm) and Securos (258±64.1 N/mm) constructs were not significantly different (P=.164; power=0.566). The mean construct stiffness for the Synthes constructs (486±91.0 N/mm) was significantly greater than that of the Slocum constructs (400±117 N/mm); P=.0468. Modes of failure for the Slocum (16/16) and Securos (8/8) constructs included plastic deformation of the implant with valgus deformity combined with fibular luxation (2/16 Slocum; 1/8 Securos) or fibular fracture (2/16 Slocum; 4/8 Securos). Most Synthes constructs underwent elastic deformation (7/8). One Synthes construct fractured in the saggital plane through the tibial plateau depression at the point of load application. Conclusions— The Slocum and Securos plate/tibia construct have similar stiffness, whereas the Synthes/tibia constructs are significantly stiffer than the Slocum/tibia constructs. Modes of fixation failure observed in this model were consistent with TPLO fixation failures observed clinically. Clinical relevance— Construct stiffness in axial load varies with implant type. Implants that confer higher stiffness to the construct may result in greater fixation stability in tibial metaphyseal osteotomies.     

Immunohistochemical Localization of RANK, RANKL and OPG in Healthy and Arthritic Canine Elbow Joints

Objective— To determine if the receptor activator of nuclear factor-κB–receptor activator of nuclear factor-κB ligand–osteoprotegerin (RANK–RANKL–OPG) system is active in bone remodeling in dogs and, if so, whether differences in expression of these mediators occur in healthy and arthritic joints.
Study Design— Experimental study.
Sample Population— Fragmented processus coronoidei (n=20) were surgically removed from dogs with elbow arthritis and 5 corresponding healthy samples from dogs euthanatized for reasons other than elbow joint disease.
Methods— Bright-field immunohistochemistry and high-resolution fluorescence microscopy were used to investigate the distribution of RANK, RANKL, and OPG in healthy and arthritic joints.
Results— All 3 molecules were identified by immunostaining of canine bone tissue. In elbow dysplasia, the number of RANK-positive osteoclasts was increased. In their vicinity, cells expressing RANKL, a mediator of osteoclast activation, were abundant whereas the number of osteoblasts having the potential to limit osteoclastogenesis and bone resorption via OPG was few.
Conclusions— The RANK–RANKL–OPG system is active in bone remodeling in dogs. In elbow dysplasia, a surplus of molecules promoting osteoclastogenesis was evident and is indicative of an imbalance between the mediators regulating bone resorption and bone formation. Both OPG and neutralizing antibodies against RANKL have the potential to counterbalance bone resorption.
Clinical Relevance— Therapeutic use of neutralizing antibodies against RANKL to inhibit osteoclast activation warrants further investigation.     

Evaluation of a Joint Distractor to Facilitate Arthroscopy of the Canine Stifle

Objectives— To assess a novel technique for arthroscopic evaluation of the canine stifle avoiding the need for fat pad debridement.
Study Design— Prospective study.
Sample Population— Cadaveric canine stifles (n=10); Client-owned dogs (15).
Methods— In cadaveric stifles, the femoropatellar space was assessed before placement of a joint distractor and examination of the femorotibial joint. Time to complete evaluation of the femoropatellar space, to observe the cruciate ligaments, and to completion of examination of the femorotibial joint were recorded. Distractor-assisted arthroscopy was then performed in 15 consecutive clinical cases. Clinical information, time to complete joint evaluation, and ability to perform any additional arthroscopic surgery were recorded.
Results— Observation and palpation of intra-articular structures were possible in all cadaveric stifles. Mean time to evaluate the femoropatellar space was 3.2 minutes (range, 2–4 minutes); to observe the cruciate ligaments, 5.8 minutes (range, 3–8 minutes); and to completion of joint inspection, 9.1 minutes (range 6–13 minutes). In the clinical cases, observation of intra-articular structures was also possible in all stifles. Mean time to complete joint inspection was 21 minutes (range, 10–40 minutes). Partial meniscectomy was performed successfully in 5 stifles.
Conclusions— Use of a joint distractor allowed arthroscopic observation of all relevant structures. Partial meniscectomy was readily performed.
Clinical Relevance— Use of a joint distractor may simplify arthroscopic assessment of the canine stifle and avoid potential morbidity associated with fat pad debridement.     

RADIOGRAPHIC DEFINITION OF THE ANTICLINAL VERTEBRA IN THE DOG

The anticlinal vertebra is a point in the caudal thoracic vertebral column at which vertebral anatomic features change. It may be used as a point of reference in diagnostic imaging studies. However, its exact definition and anatomic location are not consistent between anatomic texts. The position of the anticlinal vertebra was evaluated radiographically in 100 dogs, using three different definitions of the anticlinal vertebra. Definition P referred to perpendicularity of the spinous proceses, definition V referred to verticality of the spinous processes, and definition J referred to the orientation of the intervertebral joints. The anticlinal vertebra was assessed to be T11 in 85%, 75%, and 89% of dogs for definitions P, V, and J, respectively. Combining definitions improved the likelihood that the vertebra assessed to be the anticlinal vertebra was T11, if the combination included definition J, but at the expense of loss of sensitivity. The degree of agreement between the definitions ranged from fair to poor. The level of agreement between definitions P and J was improved for small and large dogs and the level of agreement between definitions V and J was improved for medium and large dogs. Compared with large breed dogs, small breed dogs were more likely to have T10 described as the anticlinal vertebra. The presence of transitional vertebra did not affect the position of the anticlinal vertebra. It should not be assumed that the anticlinal vertebra is T11 in all dogs. Care should be taken to define this anatomic feature accurately when using it as an anatomic landmark.     

Public Education Financing Trends and the Gray Peril Hypothesis

The effects of migrating seniors on the provision of local public services in rural communities is growing in importance because of the large number of retiring baby boomers and the increasing rate at which these retirees are locating outside traditional retirement destinations. Some communities are optimistic about attracting and retaining retirees as an economic development strategy, but others are concerned that inmigrating seniors may be reluctant to support local public services, such as education, bringing with them “Gray Peril.” This article attempts to clarify questions regarding the Gray Peril hypothesis and local ability and willingness to fund education in Tennessee, an increasingly popular retirement destination. To this end, county per pupil education expenditure growth is explained by growth trends in local property tax assessment and sales tax revenue, and migration patterns of the retirement‐aged population from 1962 to 2002.     

Germination,emergence, and persistence of Sonchus oleraceus,a major crop weed in subtropical Australia

Sonchus oleraceus (common sowthistle) is a dominant weed and has increased in prevalence in conservation cropping systems of the subtropical grain region of Australia. Four experiments were undertaken to define the environmental factors that favor its germination, emergence, and seed persistence. Seeds were germinated at constant temperatures between 5 and 35°C and water potentials between 0 and ?1.4 MPa. The maximum germination rate of 86–100% occurred at 0 and ?0.2 MPa, irrespective of the temperature when exposed to light (12 h photoperiod light/dark), but the germination rate was reduced by 72% without light. At water potentials of ?0.6 to ?0.8 MPa, the germination rate was reduced substantially by higher temperatures; no seed germinated at a water potential >?1.0 MPa. Emergence and seed persistence were measured over 30 months following seed burial at 0 (surface), 1, 2, 5, and 10 cm depths in large pots that were buried in a south‐eastern Queensland field. Seedlings emerged readily from the surface and 1 cm depth, with no emergence from below the 2 cm depth. The seedlings emerged during any season following rain but, predominantly, within 6 months of planting. Seed persistence was short‐term on the soil surface, with 2% of seeds remaining after 6 months, but it increased with the burial depth, with 12% remaining after 30 months at 10 cm. Thus, a minimal seed burial depth with reduced tillage and increased surface soil water with stubble retention has favored the proliferation of this weed in any season in a subtropical environment. However, diligent management without seed replenishment will greatly reduce this weed problem within a short period.     

CONCOMITANT LIPOSOMAL DOXORUBICIN AND DAILY PALLIATIVE RADIOTHERAPY IN ADVANCED FELINE SOFT TISSUE SARCOMAS

Local recurrence of feline soft tissue sarcomas is common despite aggressive treatment. Liposomal doxorubicin might serve as a depot radiosensitizer if administered concomitantly with daily radiotherapy and thus improve tumor control. In this pilot study, the feasibility of concomitant liposomal radiochemotherapy was evaluated in a palliative setting in 10 cats with advanced soft tissue sarcomas. Cats were treated with median number of 5 (range 5–7) daily fractions of radiotherapy and a median total dose of 20 Gy (range 20–31.5 Gy). One dose of liposomal doxorubicin was administered at the beginning of radiotherapy. Seven cats received further free or liposomal doxorubicin after completion of the liposomal doxorubicin/radiation protocol. Seven of the treated 10 cats (70%) achieved a partial (n=5) or complete (n=2) response with a median response duration of 237 days. The median progression free interval in all 10 cats was 117 days and the median overall survival time was 324 days. Concomitant liposomal radiochemotherapy was tolerated well in nine cats, one cat experienced temporary anorexia. Although the number of patients is too small to make definitive conclusions, results appear promising enough to investigate the role of liposomal doxorubicin as a radiosensitizer further.     

Canine Axial Skeletal Osteosarcoma A Retrospective Study of 116 Cases (1986 to 1989)

Axial skeletal osteosarcomas were evaluated retrospectively in 116 dogs. Thirty-one tumors occurred in the mandible, 26 in the maxilla, 17 in the spine, 14 in the cranium, 12 in the ribs, 10 in the nasal cavity and paranasal sinuses, and 6 in the pelvis. Medium-sized and large dogs were most commonly affected. Females outnumbered males 2.1:1, but this varied with tumor location. The mean age was 8.7 years. Osteosarcomas of the rib occurred in significantly younger dogs (mean age, 5.4 years) than osteosarcomas at any other axial skeletal site. Pulmonary metastasis was diagnosed radiographically in 11.1% of the dogs. The median survival for dogs treated surgically was 22 weeks, the 1-year survival was 26.3%, and the 2-year survival was 18.4%. The tumor recurrence rate was 66.7%. Most dogs (79.6%) died or were euthanatized for problems associated with the primary tumor.