Caudal cruciate ligament disease in three Basset Hounds.

CASE DESCRIPTION: 3 adult Basset Hounds were referred for evaluation of chronic, unilateral, pelvic limb lameness with no history of trauma. CLINICAL FINDINGS: On examination, all dogs had mild lameness of the affected limb; signs of pain were evident during manipulation of the stifle joint in the affected limb, along with effusion of that joint. No stifle joint instability was palpable. Radiographs were available for review for 2 of the 3 dogs. Effusion was confirmed radiographically, but severity of degenerative joint disease varied. Central intercondylar notch width ratios for the 2 dogs were 0.16 and 0.17, and tibial plateau angles were -10° and 15°; relative tibial tuberosity width was 1.1 for both dogs. Exploratory arthroscopy revealed moderate degeneration of the caudal cruciate ligament in all 3 dogs; the cranial cruciate ligaments were grossly normal. TREATMENT AND OUTCOME: Corrective osteotomy to increase the tibial plateau angle was performed in 1 dog, and the lameness resolved by 2 months after surgery. The 2 other dogs were managed without additional surgery. One dog was persistently lame. The other dog reportedly had normal limb function 2.5 years after undergoing exploratory arthroscopy. CLINICAL RELEVANCE: Morphological characteristics of the tibia in Basset Hounds may predispose to abnormal stresses on the caudal cruciate ligament. Isolated degeneration of the caudal cruciate ligament should be considered as a differential diagnosis for Basset Hounds with lameness originating from the stifle joint. Without direct inspection of the joint, caudal cruciate ligament disease could be confused for cranial cruciate ligament injury.

Ex vivo mechanical properties of a 2.5-mm bone anchor for treatment of cranial cruciate ligament rupture in toy breed dogs.

OBJECTIVE: To determine the mechanical pull-out properties of a 2.5-mm bone anchor implanted in ex vivo femurs of toy breed dogs and to determine whether there is a difference between knotted and knotless configurations. STUDY DESIGN: Experimental study. SAMPLE POPULATION: Eight paired harvested femurs. METHODS: Femurs were assigned to knotted or knotless configuration. Equal numbers of right and left femurs were tested. The caudolateral femoral condyle at the distal pole of the lateral fabella (F2 site) was drilled. The assigned configuration with braided suture combined with the bone anchor was implanted into the F2 site. Each configuration was positioned into a mechanical testing machine to measure yield load, load at 3-mm displacement, ultimate load, stiffness, and mode of failure at the beginning of the canine standing phase angle (150°). RESULTS: Mean ultimate load was 100.14 and 88.69 N (P = .798), mean yield load was 59.72 and 55.85 N (P = .708), load at 3-mm displacement was 46.72 and 43.33 N (P = .656), and stiffness was calculated to be 43.06 and 47.09 N/mm (P = .548) for knotted and knotless configurations, respectively. Mode of failure occurred primarily by anchor pull-out. CONCLUSION: The bone anchor withstood deformation at the estimated forces applied on the native cranial cruciate ligament (CCL) of toy breed dogs in both configurations. CLINICAL SIGNIFICANCE: This bone anchor may constitute a useful alternative for stabilization of the CCL deficient stifle in toy breed dogs. However, before it can be recommended for widespread use in dogs, closely monitored clinical trials must be conducted to assess outcome and complications associated with this implant.

Relationship between objective and subjective assessment of limb function in normal dogs with an experimentally induced lameness.

OBJECTIVE: To evaluate the relationship between previously used subjective and objective measures of limb function in normal dogs that had an induced lameness. STUDY DESIGN: Prospective, blinded, and induced animal model trial. ANIMALS: Normal, adult, and mixed-breed dogs (n=24) weighing 25-35 kg. METHODS: Force platform gait analysis was collected in all dogs before and after induction of lameness. All gait trials were videotaped; 60 video trials were evaluated by 3 surgeons with practice limited to small animal orthopedics and 3 first year veterinary students in an effort to establish the relationship between subjective and objective measures of lameness. Evaluators were unaware of the force platform data. RESULTS: Concordance coefficients were low for all observers and were similar between students and surgeons. These values were further decreased when normal and non-weight bearing trials were removed. Agreement with the force platform data was low even when observers only had to be within +/-10% of the ground reaction forces. When repeat trials were evaluated surgeons had a much higher repeatability compared with students. CONCLUSIONS: Subjective evaluation of the lameness in this study varied greatly between observers and agreed poorly with objective measures of limb function. CLINICAL RELEVANCE: Subjective evaluation of gait should be interpreted cautiously as an outcome measure whether performed from a single or from multiple observers.

Microchemical and surface evaluation of canine tibial plateau leveling osteotomy plates.

OBJECTIVE: To determine the microchemical and surface composition of tibial plateau leveling osteotomy (TPLO) plates before and after explantation. SAMPLE POPULATION: 7 TPLO plates surgically removed from host dogs 6 to 54 months after implantation; 2 raw unpolished-and-unpassivated 316L TPLO plates; and 2 heat-treated, polished-and-passivated, and cleaned 316L TPLO plates. PROCEDURES: Samples were removed by use of standard techniques to ensure the plate surface was not damaged. Sample pieces were dissolved and analyzed by inductively coupled plasma-mass spectrometry (ICP-MS) to determine bulk elemental composition. Other sample pieces were investigated by use of scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), and x-ray photoelectron spectroscopy (XPS) for determination of sample morphology, near-surface elemental composition, and surface elemental composition, respectively. To investigate the possibility of corrosion in situ, some samples were chemically corroded and analyzed. RESULTS: ICP-MS confirmed that elemental composition of samples was consistent with 316L stainless steel. The SEM and EDS analyses revealed trace amounts of polishing materials and a nonuniform carbonaceous biofilm on < 1% of the surface area of samples removed from the host dogs. The XPS analysis indicated an increase in the chromium-to-iron ratio on passivated surfaces, with no difference between passivated samples before implantation and after explantation. CONCLUSIONS AND CLINICAL RELEVANCE: Composition of the TPLO plates was consistent with 316L stainless steel. No chemical or topographic changes were detected in TPLO plates that had been implanted in dogs for up to 54 months. A small amount of biofilm was evident on the surface of 2 plates.

Effect of tibial plateau leveling on stability of the canine cranial cruciate-deficient stifle joint: an in vitro study.

OBJECTIVE: To evaluate the effect of tibial plateau leveling on joint motion in canine stifle joints in which the cranial cruciate ligament (CCL) had been severed. STUDY DESIGN: In vitro cadaver study. ANIMALS: Six canine cadaver hind legs. METHODS: Radiographs of the stifle joints were made to evaluate the tibial plateau angle with respect to the long axis of the tibia. The specimens were mounted in a custom-made testing device to measure cranio-caudal translation of the tibia with respect to the femur. An axial load was applied to the tibia, and its position was recorded in the normal stifle, after transection of the CCL, and after tibial plateau leveling. Further, the amount of caudal tibial thrust was measured in the tibial plateau leveled specimen while series of eight linearly increasing axial tibial loads were applied. RESULTS: Transection of the CCL resulted in cranial tibial translation when axial tibial load was applied. After tibial plateau leveling, axial loading resulted in caudal translation of the tibia. Increasing axial tibial load caused a linear increase in caudal tibial thrust in all tibial plateau-leveled specimens. CONCLUSIONS: After tibial plateau leveling, axial tibial load generates caudal tibial thrust, which increases if additional axial load is applied. CLINICAL RELEVANCE: Tibial plateau leveling osteotomy may prevent cranial translation during weight bearing in dogs with CCL rupture by converting axial load into caudal tibial thrust. The amount of caudal tibial thrust seems to be proportional to the amount of weight bearing.