Cheyney Meadows

Pressure distributions on the medial tibial plateau after medial meniscal surgery and tibial plateau levelling osteotomy in dogs

OBJECTIVE To evaluate the effect of medial meniscal release (MMR) and medial, caudal pole hemimeniscectomy (MCH) on pressure distribution in the cranial cruciate ligament (CCL) deficient canine stifle, and with tibial plateau levelling osteotomy (TPLO). ANIMALS Twelve adult dogs. METHODS In experiment one, six pairs of cadaveric canine stifles with an intact CCL were axially loaded with a servo-hydraulic material testing machine and pressure distributions were mapped and quantified using pressure sensitive films. Axial loading of each joint was then repeated following MMR, and again after MCH. In experiment two, six pairs of cadaveric canine stifles with or without TPLO were tested before and after CCL transection, and each MMR and MCH procedure using the same methods of experiment 1. RESULTS In experiment one, MMR and MCH had significant effects on the pressure distribution resulting in a 2.5-fold increase in the percentage of surface area with pressure higher than 10 MPa. In experiment two, CCL transection resulted in a significant change in pressure distribution only in the stifle without TPLO (P<0.05). Both MMR and MCH resulted in a 1.7-fold increase in the percentage of area with peak pressure in the stifle with TPLO (P<0.05). CONCLUSIONS Meniscal surgery results in a change in pressure distribution and magnitude within the medial compartment of the stifle. CLINICAL RELEVANCE Compromised function of the meniscus by either MMR or MCH result in stress concentration which may predispose to osteoarthritis.

Association of holidays, full moon, Friday the 13th, day of week, time of day, day of week, and time of year on case distribution in an urban referral small animal emergency clinic

OBJECTIVE To interrogate the association of variables: day of week, time of day, day of the year (major holidays, Friday the 13th, and the full moon), and month of year with the caseload of an urban academic emergency service. DESIGN Retrospective study. SETTING Urban small animal teaching hospital emergency clinic. ANIMALS Cats and dogs that were presented to the emergency clinic. INTERVENTIONS None. MEASUREMENTS AND MAIN RESULTS The hospital computer database was searched for all visits to the Emergency Service of the Mathew J. Ryan Veterinary Hospital of the University of Pennsylvania from January 1, 1987 through December 31, 2002. Variables included in the electronic data were date of admission, time of day of admission, species (dog or cat), hospital service the case was transferred to for ongoing care and whether the case was discharged directly from the emergency service. The association of caseload with day of week, time of day, day of the year (major holidays, Friday the 13th, and the full moon), and month of year was described and statistically evaluated. Saturdays and Sundays were the busiest days of the week and significantly increased caseload was noted for the majority of holidays (except Easter Day and Thanksgiving Day) with Memorial Day being the busiest. Midweek evenings as well as Saturday and Sunday afternoons were the busiest periods of the day. There was no association with caseload and Halloween, the full moon, or Friday the 13th. CONCLUSIONS The busiest times were midweek evenings, Saturday and Sunday afternoons, and most major holidays.