No abstract

Despite a modest complication rate, the Fixin locking bone plating system appears to be an acceptable choice of implant for the stabilization of appendicular fractures in dogs.

Objective To describe a three‐dimensional (3D) computed tomographic (CT) methodology to measure the tibial torsion angle (TTa) and to evaluate intrarater and interrater agreements and accuracy through comparison with anatomic measurements. Study design Ex vivo cadaveric study. Sample population Thirty‐six tibiae from 18 dogs. Methods Tibial torsion angle of each tibia was measured by using two CT techniques (axial and 3D volume rendering) by three raters who blindly measured TTa in duplicate. A semitransparent bone filter was used to enhance the visibility of the target anatomical landmarks for the 3D volume rendering CT technique. Tibial torsion angle was also quantitated in tibial specimens. Intrarater and interrater agreements were analyzed by using intraclass coefficients (ICC). Accuracy was evaluated by using adjusted R2 coefficients (R2 > 80% was considered acceptable). Results The 3D volume rendering CT technique had excellent intrarater and interrater agreements (ICC > 0.94) and an R2 value of 97%. The axial CT technique had good to excellent intrarater and interrater agreements (0.8 < ICC < 0.95) and an R2 of 86%. No difference was found between axial and 3D CT techniques. A mean internal TT angle of approximately −6° was found with CT and anatomic measurements. Conclusion The 3D volume rendering and axial CT techniques were precise and accurate for measuring TTa in dogs unaffected by patellar luxation. Clinical relevance Combining 3D bone manipulation with application of a semitransparent filter allows simultaneous visualization of anatomic landmarks, which may facilitate the evaluation of complex bone deformations. Internal tibial torsion may be present in nonchondrodystrophic dogs without patella luxation.

Objective: To validate a computed tomographic (CT) method to measure the femoral trochlear groove depth (FTGD). Study design: Cadaveric study. Sample population: Fifteen dogs, 26 femoral trochleae. Methods: Five points were identified from proximal to distal (proximal point [PP], P25, P50, P75, and distal point [DP]) along the trochlea via three-dimensional volume-rendering function on the sagittal plane and measured on multiplanar reconstruction images. Each rater repeated measurements in duplicate, unaware of the identity of the joint. The FTGD was quantitated on the anatomical specimens and statistically compared with CT measurements. Intrarater and interrater agreements were analyzed by using intraclass coefficients. Accuracy was evaluated by using either adjusted R2 coefficients (R2 > 80% was considered acceptable) or Student's t test. The ratio of the patellar and the trochlear width and the ratio of the patellar craniocaudal thickness inside the trochlear groove were calculated at three different patellar locations. Results: Good to excellent intrarater and interrater agreements were observed in four of five trochlear points (P25, P50, P75, and DP), and accuracy was acceptable for these points (R2 > 80%). Computed tomographic measurements differed from the mean anatomical measurements at three of five points (PP, P50, and P75; P < .01), overestimating the FTGD by an overall mean of 0.18 mm (range, 0.02-0.3). P25 and P50 were the deepest points measured. Conclusion: Computed tomography allowed precise measurements of trochlear groove depth except for the most proximal point. The deepest trochlear points were P25 and P50. P25 was the most precise and accurate point measured, while PP was the least consistent. Clinical significance: The deepest portion of the trochlea groove may be located between P25 and P50. Evaluation of this CT method in dogs with patellar luxation is recommended.

OBJECTIVE To describe the use of a customized 3–D-printed titanium prosthesis as adjunctive treatment for foramen magnum decompression (FMD) in dogs with Chiari-like malformation (CM) and syringomyelia (SM). ANIMALS 8 dogs with clinical signs and MRI findings of CM-SM. PROCEDURES 3-D reconstruction of CT images of the head was used to simulate an occipital craniectomy and design the prosthesis. FMD was performed, and the prosthesis was implanted. Follow-up was performed 1, 6, and 12 months later, and clinical status was scored. Repeated MRI images were compared to identify changes involving the neural structures, particularly the syrinx. RESULTS All prostheses were easily positioned based on the preoperative 3-D models, with no complications. At 12 months after surgery, 3 dogs were free of previous medications, 4 were still receiving steroid medications but at lower doses, and 1 was occasionally receiving acupuncture. MRI of 5 dogs 6 to 20 months after surgery revealed resolution of SM (n = 1), reduced size of SM (3), or worse SM (1). All dogs showed an increase in size of the caudal cranial fossa. Dogs with a longer presurgical duration of the clinical signs and wider syrinx generally had worse outcomes than other dogs. CLINICAL RELEVANCE Findings suggested that use of customized 3–D-printed titanium prosthesis and associated FMD can represent an adjunctive option to medically treated dogs with CM-SM. Although the small number of cases precludes definitive conclusions, early surgical treatment, particularly in dogs with a small syrinx, could ensure better long-term outcomes, as previously suggested.

Pes varus deformity in Dachshunds can be treated by medial opening wedge osteotomy of the distal tibia stabilized with a locking plate system. Care to preserve the lateral cortex of the osteotomy may help avoid under-correction.

Objectives To describe a computed tomographic (CT) methodology for planning the correction of femoral and tibial torsion and report the clinical outcomes after femoral (FDO) and tibial (TDO) detorsional osteotomy in dogs affected by torsion malalignment and patellar luxation (PL). Study design Multicenter retrospective study. Animals Eighteen client‐owned dogs. Methods Dogs underwent CT to measure femoral (FTA) and tibial torsion angle (TTA). Abnormal femoral external torsion was defined when FTA <20°, abnormal femoral internal torsion if FTA >35°; abnormal tibial external torsion was defined when TTA < −10°, and abnormal tibial internal torsion when TTA >2°. The cortical arch length (CAL) was measured with CT and used intraoperatively to determine the magnitude of correction. The medical records and radiographs were reviewed and used to report clinical and radiographic outcomes. Radiographs were reviewed to evaluate postoperative limb alignment, patellar position, and bone healing. Results Twenty‐two detorsional osteotomies were performed. Mean preoperative FTA was 14° for medial‐PL and 45.2° for lateral‐PL. Mean preoperative TTA was 11° for medial‐PL. Physiological patellar tracking was restored in 22/22 of cases. CAL measurement allowed for correction of abnormal torsion in 19/22 of cases. Seventeen out 18 dogs had full or acceptable functional outcome. The median radiographic follow‐up was 3 months. Major complications occurred in 2/22 cases, which suffered an iatrogenic abnormal femoral internal torsion and a persistent hindlimb lameness. Conclusions CAL can be measured with CT and used intraoperatively to guide the correction of abnormal torsion in dogs. Clinical relevance Abnormal femoral and tibial torsion are predisposing factors for PL. A higher complication rate is expected when FDO and TDO are performed in the same hindlimb.

This report describes the treatment of traumatic carpal hyperextension in a giant breed dog by pancarpal arthrodesis using a custom-made Fixin locking plate, created with the aid of a three-dimensional plastic model of the bones of the antebrachium produced by rapid prototyping technology. A three-year-old 104 kg male Mastiff dog was admitted for treatment of carpal hyperextension injury. After diagnosis of carpal instability, surgery was recommended. Computed tomography images were used to create a life-size three-dimensional plastic model of the forelimb. The model was used as the basis for constructing a customized 12-hole Fixin locking plate. The plate was used to attain successful pancarpal arthrodesis in the animal. Radiographic examination after 74 and 140 days revealed signs of osseous union of the arthrodesis. Further clinical and radiographic follow-up examination three years later did not reveal any changes in implant position or complications.