Minimally invasive tarsal arthrodesis in 15 dogs.

OBJECTIVE: The aim of the present study was to report the outcomes and complications of minimally invasive tarsal arthrodesis (MITA) in dogs. STUDY DESIGN: Bi-institutional retrospective study. SAMPLE POPULATION: A total of 15 client-owned dogs. METHODS: Medical records of dogs undergoing MITA were reviewed to determine outcome and complications. Radiographs were recommended every 4 weeks until clinical union and reviewed to evaluate tibiotarsometatarsal alignment, implant position, subsequent osseous union of the debrided articulations. Time to clinical union and complications were recorded. Clinical union was defined as functional weightbearing limb use with at least 50% of osseous union. Final limb function was defined as full, acceptable, or unacceptable. RESULTS: Partial tarsal arthrodesis was performed in 10 cases and pantarsal arthrodesis in five cases. Postoperative swelling was minimal. Most complications, 26% major and 40% minor, were implant-related, and explant was required in three dogs. No catastrophic complications occurred. Mean (±sd) radiographic follow-up was 11.4 (±13.1) months Mean (±sd) time to radiographic osseous union was 1.8 (±0.5) months. Mean (±sd) time to clinical union was 3.7 (±0.8) months. Physiological alignment was restored in 12/15 dogs. Complete radiographic union occurred in 46% while in the remaining 54% obtained partial radiographic union, but clinical instability was not observed. Limb function was considered full in six and acceptable in eight dogs. Function was unacceptable in one dog, but the cause was not related to MITA. CONCLUSION: MITA resulted in restoration of alignment, which was accomplished using MITA techniques. Furthermore, MITA appeared to result in faster healing times and reduced soft tissue complications compared to conventional open approach arthrodesis. CLINICAL SIGNIFICANCE: MITA may be considered as an option to obtain functional arthrodesis in dogs.

A lateral approach allows accurate and stable total elbow replacement in dogs.

OBJECTIVE: Evaluate whether total elbow replacement (TER) through a lateral approach is accurate and stable. ANIMALS: 12 skeletally mature large-breed dog cadavers were used. METHODS: Limb alignment, elbow joint motion, and collateral ligament laxity were evaluated preoperatively. The order of surgery (left or right) and the approach (lateral or medial) were randomly selected for TER in each dog. The other approach was used in the contralateral elbow. Intraoperative technical difficulties, duration of surgery, and anatomic complications were recorded. Limb alignment, elbow joint motion, collateral ligament laxity, and prosthetic component alignment were evaluated after surgery. Data were collected from June 11 to 15, 2023. RESULTS: The duration of surgery using a lateral or medial approach did not differ (P = .499). Anatomic complications were not observed. The lateral approach resulted in 8° more elbow extension (P = .003), 1.58° less lateral collateral ligament constraint (P = .033), 2.80° less medial collateral ligament constraint (P = .002), 4.38° less frontal plane constraint (P = .004), 8° greater humeral component inclination (P = .033), and 5.6° greater radioulnar component varus (P = .001) than the medial approach. Varus of the radius, mechanical axis deviation, limb supination, elbow flexion, mediolateral humeral component and craniocaudal radioulnar component orientation did not differ among joints operated using a lateral or medial approach. In normal cadaveric elbows, a lateral approach for TER appears feasible, producing equivalent limb alignment, joint laxity, and joint motion to normal elbows and to TER placed using a medial approach. CLINICAL RELEVANCE: In dogs, TER can be performed using a lateral surgical approach.

Feasibility of feline coxofemoral arthroscopy using a supratrochanteric lateral portal: A cadaveric study.

OBJECTIVE: To evaluate the feasibility of feline diagnostic coxofemoral arthroscopy. STUDY DESIGN: Ex vivo feline cadaveric descriptive study. ANIMALS: Seven feline cadavers (14 hips). METHODS: Gross dissection of two feline hips was performed to evaluate anatomic landmarks, guide arthroscopic portal development, and determine optimal limb positioning. A 1.9 mm, 0° arthroscope, inserted through a supratrochanteric lateral portal, was used to assess intraarticular structures in 12 feline cadaver hips. Arthroscopy was followed by gross dissection of periarticular soft tissues. Relative portal locations and damage to periarticular structures were recorded. Hips were disarticulated, and an India ink assay was performed to assess whether there was iatrogenic cartilage injury (ICI). RESULTS: Scope insertion was achieved in all hips. Articular cartilage of the femoral head and acetabulum, round ligament, joint capsule, transverse acetabular ligament, and dorsal acetabular rim were identified arthroscopically in all hips. Probe insertion and intra-articular structure palpation was achieved in all hips. Scope and instrument portals resulted in minimal periarticular muscle trauma. No sciatic nerve damage was detected. Minor partial thickness ICI was observed in all hips at the site of scope insertion. Focal full thickness ICI was noted in one hip. CONCLUSION: Arthroscopy of the feline coxofemoral joint allowed visual and probe evaluation of intra-articular structures without evidence of major periarticular neurovascular trauma. Iatrogenic cartilage injury occurred in all hips but severity of lesions was considered mild. CLINICAL SIGNIFICANCE: Coxofemoral arthroscopy is feasible in cats and can be utilized as a diagnostic tool for minimally invasive joint evaluation.

Effect of screw insertion angle and speed on the incidence of transcortical fracture development in a canine tibial diaphyseal model.

OBJECTIVE: To assess the incidence of transcortical fracture (TCF) development based on screw insertion angle and screw insertion speed. STUDY DESIGN: Cadaveric experimental study. SAMPLE POPULATION: Sixty-six canine tibiae. METHODS: Sixty-six cadaveric tibiae were randomly assigned to one of six groups that varied based on screw insertion angle relative to the pilot hole (0, 5, or 10°) and screw insertion speed (650 or 1350 revolutions per minute [rpm]). Each tibia was mounted in a custom jig. Locking self-tapping screws (3.5 mm) were inserted at varying speeds and insertion angles, based on group assignment. Orthogonal radiographs were evaluated for TCFs. Fisher's exact tests with a Bonferroni correction were performed to evaluate differences in the frequency of TCF between groups. RESULTS: In Group A (0°/650 rpm: control), a 0% TCF rate was observed (n = 0/80). Group B (5°/650 rpm) had a 3.75% TCF rate (n = 3/80). Group C (10°/650 rpm) had a 12.5% TCF rate (n = 10/80). Group D (10°/hand insertion) had a 3.75% TCF rate (n = 3/80). Group E (10°/1350 rpm) had a 17.5% TCF rate (n = 14/80). Group F (0°/1350 rpm) had a 0% TCF rate (n = 0/80). Groups C and E had the highest TCF rates with a difference in TCF rates observed between the control group and Group C (p = .001) and between the control group and Group E (p < .001). CONCLUSION: Increased screw insertion angle and insertion speed appear to be predisposing factors for TCF development in cadaveric bone. CLINICAL SIGNIFICANCE: Ensuring screw insertion is coaxial with the pilot hole and using slower screw insertion speeds may help reduce the risk of TCF development.

Effect of Plate Type on Tibial Plateau Levelling and Medialization Osteotomy for Treatment of Cranial Cruciate Ligament Rupture and Concomitant Medial Patellar Luxation in Small Breed Dogs: An In Vitro Study.

OBJECTIVE: The main aim of this study was to determine the effective magnitude of proximal tibial segment medialization achievable during tibial plateau levelling and medialization osteotomy (TPLO-M) with Fixin 1.9-2.5 mm pre-contoured T plates with three different offsets. METHODS: In this in vitro study, 36 tibia bone models reconstructed using stereolithography from hindlimb CT scans of a 5 kg dog and a 10 kg dog without orthopaedic disease were used. TPLO-M was performed using plates with three different offsets (2, 4 and 6 mm). Post-osteotomy radiographic and bone models measurements were performed. RESULTS: Regardless of patient weight, the +4 mm offset plates provided a translation of 2.93mm (± 0.51) while the +6 mm offset plates provided a translation of 5.03mm (± 0.47). In the 5kg dog bone model group limited bone contact at the osteotomy site was documented when using the +6mm offset plate. CONCLUSION: The +4mm and +6mm offset Fixin plates may be considered for TPLO-M in dogs weighing between 5 and 10 kg. The +6mm offset plate should be used cautiously in dogs weighing less than 10 kg since this plate may result in insufficient postoperative bone apposition at the osteotomy site.

Mechanical evaluation of canine sacroiliac joint stabilization using two short screws.

OBJECTIVE: To assess the feasibility and mechanical stability of sacroiliac (SI) joint stabilization using 2 short 3.5 mm cortical screws, each spanning an average of 23% of the width of the sacral body. STUDY DESIGN: Cadaveric experimental study. SAMPLE POPULATION: Twenty-four canine pelvis specimens. METHODS: Pelvis specimens were prepared by disarticulation of the left SI joint and osteotomy of the left pubis and left ischium, and stabilized using a single long lag screw (LLS), 2 short lag screws (SLS) or 2 short positional screws (SPS). Computed tomography (CT) imaging was used to determine standardized screw lengths for each group and was repeated following implant insertion. Specimens were secured within a servohydraulic test frame and loaded through the acetabulum to simulate weight bearing under displacement control at 4 mm/min for 20 mm total displacement. Group mechanical testing data were compared. RESULTS: Peak load, yield load, and stiffness were more than 2 times greater in both the SLS and SPS groups when compared with the LLS group. No mechanical difference was identified between the short-screw groups. CONCLUSION: Sacroiliac luxation fixation using 2 short screws created a stronger, stiffer construct when compared with fixation using a single lag screw spanning 60% of the width of the sacral body. No mechanical advantage was observed between short screws inserted in positional vs. lag fashion. CLINICAL SIGNIFICANCE: Sacroiliac luxation fixation using 2 short screws creates a mechanically superior construct with a larger region of acceptable implant positioning and potentially reduced risk of iatrogenic injury compared with conventional fixation.

Anatomic structures of the canine middle ear visible during endoscopic examination through a ventral or lateral approach.

OBJECTIVE: To describe the anatomic structures of the canine middle ear visible during endoscopic examination through ventral and lateral surgical approaches. SAMPLE: 5 cadaveric canine heads representing 4 breeds. PROCEDURES: A descriptive study was performed. For each head, a lateral approach was performed on one side and a ventral approach was performed on the opposite side. Images were obtained with a 2.7-mm, 30° telescope. RESULTS: Captured images were reviewed, and anatomic structures visualized through the lateral and ventral approaches were identified. The optimal approach, telescope position, and light post orientation to identify each anatomic structure were subjectively determined. CLINICAL RELEVANCE: Middle ear evaluation with a telescope was technically straightforward and allowed identification of middle ear structures not typically visible with an open surgical approach. Findings may serve as an anatomic reference guide for future video-assisted surgical procedures of the middle ear. A better understanding of the location of anatomic structures in the middle ear may help to prevent unnecessary damage to fragile middle ear structures, such as nerves or blood vessels, during surgical procedures.

Evaluation of a novel method to calculate cementless femoral stem level on craniocaudal projection radiographs.

OBJECTIVE: To assess the accuracy of a proportion-corrected radiographic cementless femoral stem level calculation in a cadaver model. STUDY DESIGN: Cadaveric study. SAMPLE POPULATION: Twelve cadaveric canine femurs. METHODS: Cementless femoral stems were implanted in 12 cadaver femurs at three stem levels. Craniocaudal projection radiographs of the implanted femurs were obtained at 0°, 10°, 20°, 30°, and 45° angulations in the sagittal plane (relative to the radiographic plate) and at 0°, 15°, and 30° internal and external axial rotation. A proportional calculation including actual stem length, radiographically measured stem length, and radiographically measured stem level relative to the greater trochanter (uncorrected stem level) was solved to yield a corrected stem level. The errors of the stem level measurements were compared. RESULTS: With 0° or 15° of internal rotation, the true stem level differed by more than 0.5 mm from corrected stem level in 2 of 30 tested femoral positions. It differed from the uncorrected stem level in 10 of 30 positions. With 15° and 30° external rotation or 30° internal rotation, the corrected stem level was not more accurate than the uncorrected stem level for any femoral position. CONCLUSION: Use of a proportion correction minimized variability in the stem-level measurements due to sagittal angulation (up to 30°) of the femur at 0° or 15° of internal rotation. CLINICAL SIGNIFICANCE: A proportion correction can improve the accuracy of femoral stem-level assessment on craniocaudal projection radiographs, which may aid in the detection of subsidence after cementless total hip replacement.

Prospective Clinical Evaluation of Intra-Articular Injection of Tin-117m (117mSn) Radiosynoviorthesis Agent for Management of Naturally Occurring Elbow Osteoarthritis in Dogs: A Pilot Study.

PURPOSE: To evaluate the clinical effects of an intra-articular injection of 117mSn-colloid for management of canine grade 1 or 2 elbow osteoarthritis (OA). PATIENTS AND METHODS: This was a prospective study in 23 dogs with grade 1 or 2 elbow OA. An orthopedic examination and elbow radiographs were performed to confirm the presence of OA. Dogs were randomly assigned to receive unilateral intra-articular (IA) injection of low-dose (LD: 1.0mCi, n =8), medium-dose (MD: 1.75mCi, n =6), or high-dose (HD: 2.5mCi, n =9) of 117mSn-colloid. The primary outcome measure was peak vertical force (PVF) from force-plate gait analysis and secondary outcome measures included the Canine Brief Pain Inventory score (CBPI) and elbow goniometry. The CBPI was evaluated at pretreatment and then monthly post treatment for 1 year, and goniometry and PVF were evaluated at pretreatment, and at 1, 3, 6, 9 and 12 months post treatment. RESULTS: PVF improved at 3, and 9 months compared to pretreatment values in the HD group. CBPI scores improved at most of the time points in all dose groups. There was no significant difference in elbow goniometry between treated and untreated elbows. There were no self-reports of any adverse effects of the injection by the owners and none were noted by the examining veterinarian at the time of regularly scheduled re-evaluations. CONCLUSION: 117mSn IA injection was free of any obvious adverse effects, improved CBPI scores, and increased weight bearing in limbs with elbow OA providing preliminary evidence that 117mSn may be beneficial in the management of elbow OA in dogs. Although 17mSn appeared to be effective for management of elbow OA in these dogs, this pilot study has inherent limitations; therefore, future studies with larger numbers and with placebo group are needed.

Fracture Repair in Cats Using a Conical Coupling Mini 1.9 to 2.5 mm Locking Plate System.

OBJECTIVE: The aim of this study was to retrospectively evaluate the clinical application of the Fixin mini 1.9 to 2.5 system for the treatment of long bone fractures in cats. We proposed that the Fixin mini system would successfully stabilize long bone fractures in cats with a healing time and complication rate similar to those previously reported for feline fractures using other locking bone plate systems. MATERIALS AND METHODS: Medical records and radiographs of cats with long bone fractures stabilized with the Fixin mini 1.9 to 2.5 system were retrospectively reviewed. Signalment, body weight, bone(s) fractured, region of bone fractured, fracture classification, concurrent orthopaedic injuries, complications, time to functional union, if minimally invasive plate osteosynthesis techniques were used, plate size, number of plates, bone graft use and ancillary methods of fixation were recorded. RESULTS: Fifty-six fractures in 54 cats were included. Mean time to radiographic union was 8.8 weeks. Complications were recorded in 8 out of 56 fractures. Major complications occurred in 4 of 56 fractures and minor complications occurred in 4 of 56 fractures. CONCLUSION: The Fixin mini 1.9 to 2.5 system had an overall complication rate and time to functional union similar to that of other implant systems used to treat feline long bone fractures and it appears suitable for repair of a wide variety of long bone fracture configurations in cats.