Three-Dimensional-Printed Patient-Specific Osteotomy Guides, Repositioning Guides and Titanium Plates for Acute Correction of Antebrachial Limb Deformities in Dogs.

OBJECTIVE: The aim of this study was to describe the use of patient-specific three-dimensional (3D)-printed osteotomy guides, repositioning guides and custom-printed titanium plates for acute correction of antebrachial limb deformities in four dogs. METHODS: Retrospective review of antebrachial limb deformities in small breed chondrodystrophic dogs that were surgically corrected using a closing wedge ostectomy of the radius at a predetermined site using patient-specific osteotomy guides. Reduction was achieved without the need for intraoperative measurements using patient-specific 3D-printed repositioning guides secured and manipulated using temporary Kirschner wire fixation. The ostectomy of the radius was stabilized with a patient-specific 3D-printed titanium plate. RESULTS: All limbs were corrected to within 3.5 degrees (standard deviation [SD]: 1 degree) and 7.5 degrees (SD: 3 degrees) of the pre-planned deformity correction in the frontal and sagittal planes, respectively. No complications were encountered. Owners completed a canine orthopaedic index survey at a median postoperative follow-up time of 19 months. Surgery eliminated the main presenting complaint of buckling over of the manus in all cases. CLINICAL SIGNIFICANCE: The 3D-printed osteotomy repositioning guides and titanium plates facilitated accurate acute correction of antebrachial deformities in this case series. The methodology described simplifies intraoperative surgical decision-making on limb position with good clinical outcomes seen in a small number of clinical cases.

Evaluation of the milling technique on the component-bone interface in the TATE elbow.

OBJECTIVE: To determine whether the surgeon can influence the accuracy of milling during the TATE elbow arthroplasty by applying force to the milling arm during the milling procedure. STUDY DESIGN: In vitro study on Sawbone specimens. SAMPLE POPULATION: Thirty identical solid foam models of the canine right humerus, elbow joint, and antebrachium (size large). METHODS: TATE elbow arthroplasty was performed on 30 elbows equally divided into 3 types of forces applied to the milling arm: (1) no force, (2) a maximally converging force, and (3) a maximally diverging force using the center of rotation post as a reference point. The resulting component-bone interface and post fit were quantified with digital photography. RESULTS: The component-bone interface gap differed between techniques for most angles. The application of convergent or divergent milling forces frequently increased the component-bone interface gap. Post fit was also influenced by the milling technique, application of a convergent or divergent milling force affecting the fit of multiple posts. Interface gaps tended to be greater on the lateral aspect, an area that is not visible to the surgeon intraoperatively. CONCLUSION: In this bone model study, application of convergent or divergent forces during milling frequently resulted in greater component-bone interface gaps and poorer post fit than when a neutral position was maintained. CLINICAL SIGNIFICANCE: Surgeons may affect implant fit within the constraints of the current arthroplasty system if they do not maintain a neutral position during milling. Greater component-bone interface gaps and poorer post fit may affect component osseointegration and lead to aseptic implant loosening.