Repeatability and reproducibility of measurements of femoral and tibial alignment using computed tomography multiplanar reconstructions.

OBJECTIVES: (1) To describe a protocol for measurement of the anatomic lateral distal femoral angle (aLDFA), angle of anteversion (AA), mechanical medial proximal tibial angle (mMPTA), tibial tuberosity displacement (TTD), and crural torsion angle (CTA) from computed tomography (CT) multiplanar reconstructions of canine hindlimbs. (2) To test the intra-observer variability (repeatability) and inter-observer variability (reproducibility) of the protocol. (3) To assess the proportion of variance in the measurement of each parameter explained by dog, observer, body mass, and medial patellar luxation (MPL). STUDY DESIGN: Anatomic study. ANIMALS: Twenty client-owned dogs. METHODS: A protocol for the measurement of aLDFA, AA, mMPTA, TTD, and CTA was performed by 3 observers, and performed 3 times by 1 observer, on CT multiplanar reconstructions of 20 canine hindlimbs. Intraclass correlation coefficients (ICC) were calculated for each parameter to examine intra-observer variability (repeatability) and inter-observer variability (reproducibility). The proportion of variance in the measurement of each parameter explained by dog, observer, body mass, and MPL was assessed using mixed effect, linear models. RESULTS: Intra-observer and inter-observer ICC were >0.8 for all parameters indicating good repeatability and reproducibility. Most of the variance in the measurement of each parameter was attributable to dog. CONCLUSIONS: The CT protocol, as described, was repeatable and reproducible for assessing the femoral and tibial alignment of dogs.

Prospective, Randomized Comparison of the Effect of Two Antimicrobial Regimes on Surgical Site Infection Rate in Dogs Undergoing Orthopedic Implant Surgery.

OBJECTIVES: To determine whether extending prophylactic antimicrobial administration into the postoperative period would decrease the surgical site infection (SSI) rate in clean canine orthopedic surgery associated with a metal implant. STUDY DESIGN: Randomized prospective clinical study. SAMPLE POPULATION: Consecutive procedures (n = 400) on dogs that had clean orthopedic surgery using a metal implant. METHODS: Cases were randomly allocated to 1 of 2 groups. Group 1 was only administered perioperative antimicrobial drugs whereas group 2 was administered perioperative and 5 days of postoperative antimicrobial therapy. Owners were questioned or dogs were examined at 2 and 6 weeks after surgery to identify any SSI. Long term follow-up by questionnaire of the referring veterinary surgeon ≥1 year after surgery was obtained. RESULTS: Ten of 191 dogs (5.24%) in group 1 developed SSI within 6 weeks compared with 7 of 198 (3.54%) in group 2; 7.22% of dogs in group 1 and 8.24% in group 2 developed infections more than 6 weeks after surgery. CONCLUSIONS: SSI rates in this population of dogs were similar where antimicrobial prophylaxis was administered perioperatively over 3 hours or as a course continued for 6 days.

Defining a safe corridor for transcondylar screw insertion across the canine humeral condyle: a comparison of medial and lateral surgical approaches.

OBJECTIVES: To (1) develop guidelines for the location of drill entry and exit points when inserting a transcondylar screw across the canine humerus; (2) compare the safe corridor for transcondylar screw insertion when drilling medial-to-lateral with drilling lateral-to-medial. STUDY DESIGN: Anatomic study. ANIMALS: Dogs (n = 43). METHODS: The optimum position of a transcondylar screw in 84 elbows was determined using CT multiplanar reconstructions. The positions of drill entry and exit points were defined relative to the epicondyles. Differences in elbow size were accounted for by dividing the measurements by the humeral condylar diameter (HCD), to give normalized measurements. Mean values of normalized measurements were used to develop universal guidelines for the location of drill entry and exit points. These guidelines were then applied to the 84 elbow CT reconstructions. The size of the safe corridor around this calculated drill line was determined, and expressed as tolerance angles in the frontal and transverse planes. The size of the safe corridors for medial-to-lateral and lateral-to-medial drilling were compared. RESULTS: The lateral entry/exit point was 0.3 × HCD cranial and 0.3 × HCD distal to the lateral epicondyle. The medial entry/exit point was 0.3 × HCD cranial and 0.2 × HCD distal to the medial epicondyle. Using these guidelines resulted in safe virtual screw placement in all 84 elbows. The tolerance angle in the frontal plane was significantly smaller when drilling medial-to-lateral compared with drilling lateral-to-medial (P < .001). CONCLUSIONS: Medial-to-lateral drilling for transcondylar screw placement carries a higher risk of inadvertently penetrating the joint compared with lateral-to-medial drilling.