OBJECTIVE:To investigate the effects of muscle activation on internal tibial rotation and cranio-caudal translation (CCT) in intact and cranial cruciate ligament (CCL) deficient stifles. STUDY DESIGN:Ex vivo biomechanical study. ANIMALS:Eight cadaveric, nonpaired canine stifles. METHODS:Stifles were tested intact and after arthroscopic CCL transection. Quadriceps, biceps femoris, and gastrocnemius forces were simulated with pneumatic actuators in single or cocontraction muscle activation (0%-100% bodyweight [BW]). The tibia was mounted to a linear-torsional tester; the femur to a six-degrees-of freedom fixture. Internal tibial rotation (5 Nm torque) and CCT (30% BW cranial and caudal translation) were recorded via motion tracking system. RESULTS:Without muscle activation, CCL transection increased internal tibial rotation (34.8 ± 11.8° CCL-deficient vs. 27.9 ± 10.8° intact; p = .041). Across 0%-100% BW activation, internal rotation decreased in both conditions, to 4.3 ± 2.3° (intact; p < .0001 vs. 0% BW) and 2.8 ± 1.3° (CCL-deficient; p = .001 vs. 0% BW) at 100% BW. At 100% BW, biceps femoris reduced internal rotation more than quadriceps and gastrocnemius in both CCL conditions. Muscle activation reduced CCT in CCL-deficient stifles; however, at 100% BW, CCT was 19.1 mm in CCL-deficient versus 2.8 mm in intact (+582%; p < .0001). CONCLUSION:Periarticular muscle activation mitigates axial plane rotational laxity but does not prevent CCT. CLINICAL SIGNIFICANCE:Targeted muscle strengthening may help manage rotational laxity; however, surgical stabilization remains necessary to address CCT after CCL rupture. Internal tibial rotation may require additional surgical stabilization in selected cases.

Degenerative lumbosacral stenosis (DLSS) in dogs can involve foraminal stenosis and L7 nerve root compression. Surgical options to expand the L7-S1 neuroforamen (NF) include foraminotomy and distraction-stabilization. However, the efficacy of these techniques when subjected to biomechanical loading is unclear. The study objective was to investigate the influence of spinal motion on the volume of the L7-S1 NF in the native spine and after foraminotomy and distraction-stabilization. Eight canine cadaveric spines were subsequently tested in 3 conditions: native, after unilateral foraminotomy and after distraction-stabilization of L7-S1. Spines were subjected to axial compression, flexion/extension, lateral bending and axial rotation. The volume of the L7-S1 NF was calculated for each condition and motion direction. Linear mixed models were used to analyze differences between motions and conditions. The NF in the native spine was only affected by flexion (+4.5 %±16.6;P < 0.01) and extension (-36.7 %±11.1;P < 0.01) when compared to the position neutral + axial compression. The NF dimension after foraminotomy increased in flexion (+20.4 %±24.6;P < 0.01) and decreased in extension (-35.9 %±9.3;P < 0.01). In contrast, the NF after distraction-stabilization was not affected by biomechanical motion. Foraminotomy resulted in significantly increased volumes in all loading conditions (+31.0-45.7 %;P < 0.01). Distraction-stabilization produced smaller, yet statistically significant, increases in foraminal volume across several loading directions: axial compression (+15 %±18.0;P = 0.01), ipsilateral lateral bending (+22.1 %±19.0;P < 0.01), extension (+75 %±31.6;P < 0.01) and ipsilateral (+9.3 %±12.9;P = 0.01) and contralateral axial rotation (+12.7 %±12.9;P = 0.01). Both foraminotomy and distraction-stabilization lead to significant increases in the volume of the L7-S1 NF throughout spinal movement. As such, either procedure may be effective in enlarging the L7-S1 neuroforamen compromised by DLSS.

OBJECTIVE:To determine whether structured and supervised cadaveric surgical training improves technical skills in expert and self-assessments and enhances self-perception of surgical trainees. STUDY DESIGN:Prospective observational study. SAMPLE POPULATION:Seven small animal ECVS residents and surgical interns. METHODS:A cadaveric orthopedic training program, consisting of six supervised training sessions, weekly self-directed training, and one one-to-one training session with direct feedback, was conducted over 3 months. Each participant performed a set of surgical procedures on feline cadavers before and after the training period. The procedures were videotaped and subsequently evaluated by three board-certified surgeons (expert assessment [EA]) and the participants themselves (self-assessment [SA]) using the objective structured assessment of technical skills (OSATS) global rating scale (GRS). OSATS GRS scores were analyzed using the Wilcoxon signed-rank test, Kruskal-Wallis test, and Cohen's kappa coefficient (Κ). RESULTS:Comparing pre- and post-training assessments, median EA scores increased from 17/35 to 23/35 (p = .001). Median SA scores increased from 17/35 to 25/35 (p = .018). There was slight to substantial inter-assessor agreement (Κ = 0.04-0.65) and poor agreement between SA and EA (Κ = 0). CONCLUSION:Trainee surgeons improved their technical skills in expert and self-assessments. However, the interassessor agreement was strong for only two of the three assessors. Despite limitations, the OSATS GRS enhanced the objectivity of technical surgical skills assessment. CLINICAL SIGNIFICANCE:This study represents the first step in devising a meaningful training outside the operating room for veterinary surgical residents. The OSATS GRS as an assessment tool warrants further investigation.

OBJECTIVE:The aim of this cadaveric study was to compare the biomechanical outcomes of three methods of stabilization for tibial tuberosity transposition to treat medial patellar luxation: a complete osteotomy with a two-pin and tension band wire (TBW) fixation (TBW group), a partial osteotomy with a two-pin fixation (2 Pin group), and a partial osteotomy with a spacer pin fixation (Spacer Pin group). STUDY DESIGN:Thirty medium to large-sized canine cadaveric tibiae were dissected and randomly assigned to one of three groups: TBW, 2 Pin, and Spacer Pin groups. The patellar ligaments were loaded in tension until ultimate failure. Ultimate failure force and mode of failure were documented, stiffness was calculated, and the results were compared statistically between the three treatment groups. RESULTS:There were not any significant differences in ultimate failure force or stiffness between groups. All groups predominantly failed by patellar ligament failure, with distal tibial crest fracture/displacement being the second-most common mode in the 2 Pin and Spacer Pin groups. CONCLUSION:The mechanical properties of the spacer pin stabilization were not different from the TBW and 2 Pin groups. The spacer pin technique could be an alternative way to stabilize tibial tuberosity following tibial tuberosity transposition with a partial osteotomy based on this cadaveric load-to-failure model.

OBJECTIVES:To investigate stifle kinematics and kinetics following TPLO and TPLO combined with an extra-articular lateral augmentation (TPLO-IB) during the tibial compression test (TCT) and the tibial pivot compression test (TPT), applied with an external (eTPT) and an internal moment (iTPT).STUDY DESIGN:Experimental ex vivo study.SAMPLE POPULATION:Ten cadaveric hindlimbs of dogs weighing 23-40 kg.METHODS:3D-kinematic and kinetic data were collected while performing TCT, eTPT, and iTPT and compared under the conditions (1) normal, (2) CCL deficient, (3) TPLO, and (4) TPLO-IB. Two-way repeated-measures ANOVA was used to examine the effect of test and treatment on kinetic and kinematic data.RESULTS:Mean ± SD preoperative TPA was 24.7° ± 1.7°, postoperative TPA was 5.9° ± 0.7°. During TCT, there was no difference in cranial tibial translation between the intact stifle and after TPLO (p = .17). In contrast, cranial tibial translation was six times larger in TPLO compared to intact when performing eTPT and iTPT (p < .001). Cranial tibial translation with TCT, eTPT and iTPT was not different between intact stifle and TPLO-IB. Intraclass correlation coefficient for eTPT and iTPT after TPLO and TPLO-IB was excellent being 0.93 (0.70-0.99) and 0.91 (0.73-0.99), respectively.CONCLUSION:Whereas TCT is negative after TPLO, instability persists when a rotational moment is combined using eTPT and iTPT. TPLO-IB neutralizes craniocaudal and rotational instability when performing TCT, eTPT, and iTPT.

OBJECTIVES:To investigate the accuracy and intra- and interobserver reliability of the cranial drawer test (CD), tibial compression test (TCT), and the new tibial pivot compression test (TPCT) in an experimental setting resembling acute cranial cruciate ligament rupture (CCLR) and to elucidate the ability to subjectively estimate cranial tibial translation (CTT) during testing.STUDY DESIGN:Experimental ex vivo study.SAMPLE POPULATION:Ten cadaveric hindlimbs of large dogs.METHODS:Kinetic and 3D-kinematic data was collected while three observers performed the tests on each specimen with intact (INTACT) and transected cranial cruciate ligament (CCLD) and compared using three-way repeated-measures ANOVA. Subjectively estimated CTT (SCTT), obtained during a separate round of testing, was compared to kinematic data by Pearson correlation.RESULTS:CTT was significantly higher for CCLD than for INTACT for all tests, resulting in 100% sensitivity and specificity. TPCT induced the highest CTT and internal rotation. Intra- and interobserver agreement of translation was excellent. For rotation and kinetics, agreement was more variable. SCTT strongly correlated with the objectively measured values.CONCLUSION:The CD, TCT and the new TPCT were all accurate and reliable. The high translations and rotations during TPCT are promising, encouraging further development of this test. SCTT was reliable in our experimental setting.CLINICAL SIGNIFICANCE:Veterinary manual laxity tests are accurate and reliable in acute CCLR. The TPCT might have potential for the assessment of subtle and rotational canine stifle instabilities. The high reliability of SCTT implies that grading schemes for stifle laxity, similar to human medicine, could be developed.

Degenerative lumbosacral stenosis in dogs frequently involves L7-S1 foraminal stenosis and L7 nerve root compression. Surgical techniques to decompress the L7 nerve root include foraminotomy and intervertebral distraction. The objective of this study was to compare the effect of foraminotomy and intervertebral distraction on the total, cranial, and caudal compartmental volumes of the L7-S1 intervertebral neurovascular foramen (NF). CT images were obtained from eight canine lumbosacral (L5-CD1) specimens in the following sequential conditions: native spine (1), after dorsal laminectomy and partial discectomy of L7-S1 (2), after L7-S1 foraminotomy (3), after distraction with an interbody cage between L7 and S1 (4), after cage distraction stabilized with pedicle screw-rod fixation in neutral (5) and flexed position (6). The volume of the complete NF and its cranial and caudal subcompartments were calculated using the CT images and statistically compared between conditions. P < 0.05 was considered statistically significant. The volume of the complete NF was significantly increased after foraminotomy (mean +/- standard deviation (146.8 +/- 26.5%, P < 0.01) and after distraction (Condition 4, 121.0 +/- 19.1%; Condition 5, 116.6 +/- 29.3 %; Condition 6, 119.0 +/- 21.8 %; P = 0.01) with no difference between the distraction conditions. Foraminotomy induced a significantly larger increase in total NF volume compared to distraction. Foraminotomy, but not distraction, induced a significant increase in volume of the cranial subcompartment (158.2 +/- 33.2 %; P < 0.01). Foraminotomy is more effective in increasing the foraminal volume and especially the cranial subcompartment, which is where the L7 nerve root traverses the NF. Hence, foraminotomy may be more effective in decompressing the L7 nerve root. (C) 2020 Published by Elsevier Ltd.

The dog has been used extensively as an experimental model to study meniscal treatments such as meniscectomy, meniscal repair and regeneration. Accurate quantification of meniscal size and morphology are a crucial step for developing models of the meniscus. 3.0T magnetic resonance imaging (MRI) has been found to be highly accurate in analyzing the meniscus in both clinical and research fields. However, 3.0T MRI systems are still uncommonly used in veterinary medicine. The goal of the study was to compare meniscal volume measurements from 1.5T MRI system with 3.0T MRI system using proton density sequence, a clinically relevant protocol. The MR images were segmented to reconstruct 3D surface representations of both medial and lateral menisci to compare the meniscal volumes measurements. Average volume differences were 8.8% (P=0.42) and 8.9% (P=0.535) for medial and lateral meniscus, respectively. No significant volume differences were found between 1.5T and 3.0T magnetic resonance (MR) measurements, with high Pearson's correlation coefficient of r > 0.8 and the intraclass correlation coefficient (ICC) of 0.899. For inter- and intra-observer reproducibility, high correlation (ICC = 0.942 and 0.814) was observed, but with high variability for intra-observer reproducibility (lower bound 0.478, upper bound 0.949). We have shown that common clinical MR scanners and pulse sequences can be used to quantify dogs' meniscal volumes with good reproducibility. We believe that repeatable measurements of meniscal volumes using MR may provide a useful capability for assessment of postoperative results following meniscal treatments such as meniscectomy and meniscal regeneration.