Clinical use of computer-assisted orthopedic surgery in horses.

OBJECTIVE: To describe clinical applications of computer-assisted orthopedic surgery (CAOS) in horses with a navigation system coupled with a cone beam computed tomography unit. STUDY DESIGN: Retrospective clinical case series. ANIMALS: Thirteen adult horses surgically treated with CAOS. METHODS: Medical records were searched for horses that underwent CAOS between 2016 and 2019. Data retrieved included signalment, diagnosis, lameness grade prior to surgery, surgical technique and complications, anesthesia and surgery time, and information pertaining to the perioperative case management and outcome. RESULTS: In 10 cases, surgical implants were placed in the proximal phalanx, third metatarsal bone, ulna, or medial femoral condyle. In one case, navigated transarticular drilling was performed to promote ankylosis of the distal tarsal joints. In another case, an articular fragment of the middle phalanx was removed with the help of CAOS guidance. In the final case, a focal osteolytic lesion of the calcaneal tuber was curetted with the aid of CAOS. In seven cases, a purpose-built frame was used for the surgical procedure. All surgeries were performed successfully and according to the preoperative plan. CONCLUSION: Computer-assisted orthopedic surgery can be an integral part of the clinical case management in equine surgery. To optimize workflow and time-efficiency, the authors recommend designating one team for operative planning and another for the execution of the surgical plan. Specialized equipment, such as the purpose-built frame, will further improve CAOS applications in equine surgery. CLINICAL SIGNIFICANCE: After they have become familiar with the operational principles, equine surgeons can readily apply CAOS for a broad spectrum of indications.

Semi-Automatic Segmentation of Cone Beam Computed Tomography Datasets for Volume Measurements of Equine Cheek Teeth.

The volumes of equine teeth may change considerably over time for several reasons including domestication, routine dental floating, and the hypsodont and anelodont nature of the teeth. Cone beam computed tomography (CBCT) of the head is routinely performed in standing horses and, in this proof of concept study, the feasibility of measuring tooth volume from CBCT datasets was determined. The CBCT images of 5 equine cadaver cheek teeth were segmented with a software 3-dimensional (3D) Slicer using a predefined protocol, corrected manually, and re-assembled into a 3D model. Individual tooth volume (VS) was calculated from the model. After extraction, the volumes were also measured using the "gold-standard" water displacement method (VW) for comparison. The VS of 77 teeth ranged from 7114 to 42,300 mm3 which strongly correlated with VW (r = 0.99), and on average VS was 6.1% less than VW. There was no significant difference in VS between the right and left arcades in individual animals. Maxillary cheek tooth volume was on average 40% larger than it was for mandibular counterparts. Semi-automatic image segmentation of equine cheek teeth from CBCT data is feasible and accurate but requires some manual intervention. This preliminary study provides initial data on the volume of equine cheek teeth and creates new possibilities for future in vivo studies.

Evaluation of the effects of performance dentistry on equine rideability: a randomized, blinded, controlled trial.

OBJECTIVE: This study attempted to determine: (1) if degree of dental malocclusion assigned prior to dental treatment was associated with equine rideability, assessed using a standardized score and (2) if performance dentistry improved this score. ANIMALS: Thirty-eight Franches-Montagnes stallions. METHODS: All horses were examined and assigned a dental malocclusion score by a veterinary dentist and randomized into two groups: sham treatment (Group S) and performance dentistry including occlusal equilibration (Group D). The horses were ridden twice before and three times after treatment by a professional dressage rider (unaware of treatment allocation). The horses were assigned a rideability score using a 27-point scale. The malocclusion score was compared to the average of the first two rideability scores using Spearman's coefficient of rank. Change in rideability scores over time was assessed by repeated measures ANOVA. Statistical significance was set at P < 0.05. RESULTS: There was no correlation between dental score and rideability score prior to treatment (rs = 0.06, P = 0.73). In addition, there were no differences in the rideability score between treatment groups or as an interaction of treatment group and time (P = 0.93, P = 0.83, respectively). CONCLUSIONS: In conclusion, we were unable to show that performance dentistry improved equine rideability assessed by rider scoring. The addition of more objective measurement tools and a longer assessment period may help to scientifically prove what is anecdotally believed.

Salter-Harris type II metacarpal and metatarsal fracture in three foals. Treatment by minimally-invasive lag screw osteosynthesis combined with external coaptation.

OBJECTIVES: To describe minimally-invasive lag screw osteosynthesis combined with external coaptation for the treatment of Salter-Harris type II third metacarpal and third metatarsal bone fractures. METHODS: Three foals aged two weeks to four months with a Salter-Harris type II third metacarpal or third metatarsal fracture. Surgery was carried out under general anaesthesia in lateral recumbency. After fracture reduction, the metaphyseal fragment was stabilized with two cortical screws placed in lag fashion under fluoroscopic control. A cast was applied for at least two weeks. RESULTS: All foals had a good outcome with complete fracture healing and return to complete soundness without any angular limb deformity. All foals had moderate transient digital hyperextension after cast removal. CLINICAL SIGNIFICANCE: Internal fixation of Salter-Harris type II third metacarpal or third metatarsal fractures with two cortical screws in lag fashion, combined with external coaptation provided good stabilization and preserved the longitudinal growth potential of the injured physis.