Veterinary and Comparative Orthopaedics and Traumatology, 2019
Objective The aim of this study was to compare approximations to the tibial distal anatomical axi... more Objective The aim of this study was to compare approximations to the tibial distal anatomical axis (DAA) with regression lines for the symmetric axis of the tibia, and to identify an optimal approximation for surgical planning of osteotomies for the management of canine cruciate ligament deficiency. Study Design Prospective radiographic study of 20 canine tibiae. Using curve-fitting and the symmetric axis technique, the true anatomical axis was identified for each tibia. Regression lines were calculated for the distal 67% and distal 50% subsections of this axis. Angular deviations between these lines and DAA approximations were calculated and compared with to find the closest approximations. Results The DAA approximations based on the distal 50% rather than the distal 67% of the tibia had smaller maximal deviations from the true axis. Landmarks at 50% and 75% of tibial length exhibited greater deviations than those at 50% and 95% or 100%. Conclusion The DAA landmarks should be restr...
To compare repeatability and equivalency of measures of femoral trochlea depth and trochlear angl... more To compare repeatability and equivalency of measures of femoral trochlea depth and trochlear angle in red foxes (Vulpes vulpes) determined by use of radiography, ultrasonography, and digital photography of cadaver limbs. 24 pelvic limbs from 12 red fox cadavers. Cranioproximal-craniodistal oblique (skyline) and lateromedial radiographic views of the stifle joint and ultrasonographic images at 5 locations along the femoral trochlea were used in the study. Spacing of the 5 locations was determined on the basis of patellar position with the stifle joint at various caudal angles ranging from 96° to maximal extension (approx 170°). Ultrasonographic measurements were compared with those obtained at matched locations on photographs of anatomic preparations. Trochlear depth was assessed with all 3 image formats, and trochlear angle (measured between the trochlear ridges and sulcus) was assessed on radiographs and ultrasonographic images. Patellar thickness was measured on radiographs. Value...
Patellar luxation in large-breed dogs is associated with abnormal proximodistal patellar position... more Patellar luxation in large-breed dogs is associated with abnormal proximodistal patellar positioning. Using a clinically normal population of Greenland sled dogs, measurement reliability and the effect of limb position were compared for five patellar proximodistal positioning indices based on the Insall-Salvati (IS), modified Insall-Salvati (mIS), de Carvalho (dC), patellotrochlear (PT) and Blackburne-Peel (BP) indices. Indices were measured at one knee angle in 44 dogs and two knee angles in 10 dogs. Index susceptibility to error was modelled for different errors in knee angle estimation. Two reported techniques for determining knee angle were compared in a fox hind limb model. Indices dC and PT were significantly affected by knee angle (P<0.001). Error susceptibility was the lowest for IS and the greatest for PT. Intra- and inter-observer agreements were moderate to substantial for all indices. Measurement precision was good for all indices except BP. Patellar ligament laxity s...
Objective-To compare 5 patellar position indices at various stifle joint angles in cadavers of re... more Objective-To compare 5 patellar position indices at various stifle joint angles in cadavers of red foxes, determine measurement reliability, and assess the suitability of these indices for clinical use. Sample-Pelvic limbs from cadavers of 12 red foxes (Vulpes vulpes). Procedures-Patellar position in each limb at 7 stifle joint angles (30° to 148°) was assessed by use of the Insall-Salvati (IS), modified Insall-Salvati (mIS), de Carvalho (dC), patellotrochlear (PT), and Blackburne-Peel (BP) indices. Results-Values for all indices varied significantly on the basis of joint angle, but for IS and mIS indices, this was minor and nonsignificant between 52° and 130° and between 52° and 148°, respectively. The dC index increased linearly, and PT and BP indices varied polynomially with increases in stifle joint angle. Stifle joint angles measured from radiographs agreed well with the goniometrically set stifle joint angles up to approximately 100° and diverged thereafter. Intraobserver and interobserver agreement was substantial for all indices, and IS index was the most precise. Conclusions and Clinical Relevance-IS and mIS index values were effectively independent of stifle joint angle, in contrast to dC, PT, and BP indices. The BP index varied nonsignificantly across a range of joint angles. To maximize angular accuracy, radiographs should not be obtained at joint angles > 100°. Although dC, PT, and BP indices appeared to be suitable for preoperative and postoperative evaluation of patellar position, BP index appeared to have the most promise for determination of patellar position in clinical applications. (Am
Objective-To describe CT image reconstruction criteria for measurement of the tibial tuberosity-t... more Objective-To describe CT image reconstruction criteria for measurement of the tibial tuberosity-trochlear groove (TT-TG) offset distance, evaluate intra-and inter-reconstruction repeatability, and identify key sources of error in the measurement technique, as determined in vulpine hind limbs. Animals-12 red fox (Vulpes vulpes) cadavers. Procedures-CT images of each hind limb in intact cadavers were obtained; at 1-week intervals, 3 reconstructions were performed that were based on 1 plane passing through the centers of the femoral head and medial condyle and parallel to the caudal femoral condyles, 1 plane aligned with the femoral trochlea, and a third orthogonal plane. Randomized and anonymized reconstructions were assessed for TT-TG offset distance with a singleimage technique by 1 observer, and inter-reconstruction repeatability and intra-and interreconstruction measurement repeatability were assessed via the repeatability coefficient and intraclass correlation coefficient. Results-Multiplanar reconstructions of hind limb images were repeatedly made to within a few degrees of each other. Intra-and inter-reconstruction repeatability for TT-TG offset distance measurement was good. Repeatability was most affected by accurate identification of the tibial tuberosity and femoral trochlea landmarks. Conclusions and Clinical Relevance-Results obtained from vulpine hind limb CT images indicated that reconstructions can be made with a high degree of repeatability when based on strictly defined and applied criteria. The TT-TG offset distance has potential as an objective assessment of alignment of the distal portion of the quadriceps mechanism; its use as an aid in case selection for corrective femoral osteotomy among dogs with medial patellar luxation warrants investigation.
Objectives: To evaluate the effect of measurement technique and limb positioning on quadriceps (Q... more Objectives: To evaluate the effect of measurement technique and limb positioning on quadriceps (Q) angle measurement, intra-and interobserver reliability, potential sources of error, and the effect of Q angle variation. Study Design: Cadaveric radiographic study and computer modeling. Animals: Pelvic limbs from red foxes (Vulpes vulpes). Methods: Q angles were measured on hip dysplasia (HD) and whole limb (WL) view radiographs of each limb between the acetabular rim, mid-point (Q1: patellar center, Q2: femoral trochlea), and tibial tuberosity. Errors of 0.5-2.0 mm at measurement landmarks alone and in combination were modeled to identify the effect on Q angle. The effect of measured Q angles on the medial force exerted on the patella (F MEDIAL) was calculated. Results: The HD position yielded significantly (P < .001) more medial Q angles than the WL position. No significant difference was observed between Q1 and Q2, but Bland-Altman plots indicated they were not equivalent. Intra-and interobserver agreement was substantial. Q2 errors were inherently greater than Q1: the mid-point and tibial tuberosity are the most important sources of Q angle variability. Increasing Q angles significantly increased the exerted F MEDIAL (P < .0001, gradient 1.7%). Conclusions: Measurements are reliable, but Q2 is more prone to error than Q1, and the 2 measurement techniques are not interchangeable. Positional errors must be kept below 1.3 mm (Q1) or 0.8 mm (Q2).
OBJECTIVE To evaluate the effect of center of angulation of rotation (CORA)-based leveling osteot... more OBJECTIVE To evaluate the effect of center of angulation of rotation (CORA)-based leveling osteotomy (CBLO) and hamstring load on stifle stability following cranial cruciate ligament transection (CCLx) and medial meniscal release (MMR). STUDY DESIGN Ex vivo experimental study. SAMPLE POPULATION Cadaver hind limb preparations (n = 7). METHODS After instrumentation, constant quadriceps and gastrocnemius loads with an optional hamstring load in a 3:1:0.6 ratio were applied, and stifles were extended from fully flexed using an electrical motor during fluoroscopic recording. The recording process was repeated after each of CCLx, MMR and CBLO and the extracted landmark coordinates were used for calculation of cranial tibial translation (CTT) and patellar ligament angle (PTA). RESULTS Mean initial tibial plateau angle was 28.1°: post-CBLO the mean was 9.7°. Cranial tibial translation developed from 50° and 75° with CCLx and MMR respectively (p < .04, < .02) without hamstring loading. Hamstring loading mitigated CTT due to CCLx and delayed CTT until 120° for MMR (P < .02) in this model. CBLO prevented CTT, except at 140° without hamstring loading (P = .01). Similar results were seen for PTA, but CBLO curves were parallel to and lower than intact values at all tested angles (P < .04), consistent with induced effective joint flexion. CONCLUSION CBLO to a target tibial plateau angle of 10° largely eliminated CTT induced by CCLx and MMR. Hamstring loads of 20% quadriceps load improved stifle stability in this model. IMPACT Stifle stability following CBLO appears to be multifactorial and depends on meniscal integrity, joint angle, and hamstring strength.
Veterinary and Comparative Orthopaedics and Traumatology, 2019
Objective The aim of this study was to compare approximations to the tibial distal anatomical axi... more Objective The aim of this study was to compare approximations to the tibial distal anatomical axis (DAA) with regression lines for the symmetric axis of the tibia, and to identify an optimal approximation for surgical planning of osteotomies for the management of canine cruciate ligament deficiency. Study Design Prospective radiographic study of 20 canine tibiae. Using curve-fitting and the symmetric axis technique, the true anatomical axis was identified for each tibia. Regression lines were calculated for the distal 67% and distal 50% subsections of this axis. Angular deviations between these lines and DAA approximations were calculated and compared with to find the closest approximations. Results The DAA approximations based on the distal 50% rather than the distal 67% of the tibia had smaller maximal deviations from the true axis. Landmarks at 50% and 75% of tibial length exhibited greater deviations than those at 50% and 95% or 100%. Conclusion The DAA landmarks should be restr...
To compare repeatability and equivalency of measures of femoral trochlea depth and trochlear angl... more To compare repeatability and equivalency of measures of femoral trochlea depth and trochlear angle in red foxes (Vulpes vulpes) determined by use of radiography, ultrasonography, and digital photography of cadaver limbs. 24 pelvic limbs from 12 red fox cadavers. Cranioproximal-craniodistal oblique (skyline) and lateromedial radiographic views of the stifle joint and ultrasonographic images at 5 locations along the femoral trochlea were used in the study. Spacing of the 5 locations was determined on the basis of patellar position with the stifle joint at various caudal angles ranging from 96° to maximal extension (approx 170°). Ultrasonographic measurements were compared with those obtained at matched locations on photographs of anatomic preparations. Trochlear depth was assessed with all 3 image formats, and trochlear angle (measured between the trochlear ridges and sulcus) was assessed on radiographs and ultrasonographic images. Patellar thickness was measured on radiographs. Value...
Patellar luxation in large-breed dogs is associated with abnormal proximodistal patellar position... more Patellar luxation in large-breed dogs is associated with abnormal proximodistal patellar positioning. Using a clinically normal population of Greenland sled dogs, measurement reliability and the effect of limb position were compared for five patellar proximodistal positioning indices based on the Insall-Salvati (IS), modified Insall-Salvati (mIS), de Carvalho (dC), patellotrochlear (PT) and Blackburne-Peel (BP) indices. Indices were measured at one knee angle in 44 dogs and two knee angles in 10 dogs. Index susceptibility to error was modelled for different errors in knee angle estimation. Two reported techniques for determining knee angle were compared in a fox hind limb model. Indices dC and PT were significantly affected by knee angle (P<0.001). Error susceptibility was the lowest for IS and the greatest for PT. Intra- and inter-observer agreements were moderate to substantial for all indices. Measurement precision was good for all indices except BP. Patellar ligament laxity s...
Objective-To compare 5 patellar position indices at various stifle joint angles in cadavers of re... more Objective-To compare 5 patellar position indices at various stifle joint angles in cadavers of red foxes, determine measurement reliability, and assess the suitability of these indices for clinical use. Sample-Pelvic limbs from cadavers of 12 red foxes (Vulpes vulpes). Procedures-Patellar position in each limb at 7 stifle joint angles (30° to 148°) was assessed by use of the Insall-Salvati (IS), modified Insall-Salvati (mIS), de Carvalho (dC), patellotrochlear (PT), and Blackburne-Peel (BP) indices. Results-Values for all indices varied significantly on the basis of joint angle, but for IS and mIS indices, this was minor and nonsignificant between 52° and 130° and between 52° and 148°, respectively. The dC index increased linearly, and PT and BP indices varied polynomially with increases in stifle joint angle. Stifle joint angles measured from radiographs agreed well with the goniometrically set stifle joint angles up to approximately 100° and diverged thereafter. Intraobserver and interobserver agreement was substantial for all indices, and IS index was the most precise. Conclusions and Clinical Relevance-IS and mIS index values were effectively independent of stifle joint angle, in contrast to dC, PT, and BP indices. The BP index varied nonsignificantly across a range of joint angles. To maximize angular accuracy, radiographs should not be obtained at joint angles > 100°. Although dC, PT, and BP indices appeared to be suitable for preoperative and postoperative evaluation of patellar position, BP index appeared to have the most promise for determination of patellar position in clinical applications. (Am
Objective-To describe CT image reconstruction criteria for measurement of the tibial tuberosity-t... more Objective-To describe CT image reconstruction criteria for measurement of the tibial tuberosity-trochlear groove (TT-TG) offset distance, evaluate intra-and inter-reconstruction repeatability, and identify key sources of error in the measurement technique, as determined in vulpine hind limbs. Animals-12 red fox (Vulpes vulpes) cadavers. Procedures-CT images of each hind limb in intact cadavers were obtained; at 1-week intervals, 3 reconstructions were performed that were based on 1 plane passing through the centers of the femoral head and medial condyle and parallel to the caudal femoral condyles, 1 plane aligned with the femoral trochlea, and a third orthogonal plane. Randomized and anonymized reconstructions were assessed for TT-TG offset distance with a singleimage technique by 1 observer, and inter-reconstruction repeatability and intra-and interreconstruction measurement repeatability were assessed via the repeatability coefficient and intraclass correlation coefficient. Results-Multiplanar reconstructions of hind limb images were repeatedly made to within a few degrees of each other. Intra-and inter-reconstruction repeatability for TT-TG offset distance measurement was good. Repeatability was most affected by accurate identification of the tibial tuberosity and femoral trochlea landmarks. Conclusions and Clinical Relevance-Results obtained from vulpine hind limb CT images indicated that reconstructions can be made with a high degree of repeatability when based on strictly defined and applied criteria. The TT-TG offset distance has potential as an objective assessment of alignment of the distal portion of the quadriceps mechanism; its use as an aid in case selection for corrective femoral osteotomy among dogs with medial patellar luxation warrants investigation.
Objectives: To evaluate the effect of measurement technique and limb positioning on quadriceps (Q... more Objectives: To evaluate the effect of measurement technique and limb positioning on quadriceps (Q) angle measurement, intra-and interobserver reliability, potential sources of error, and the effect of Q angle variation. Study Design: Cadaveric radiographic study and computer modeling. Animals: Pelvic limbs from red foxes (Vulpes vulpes). Methods: Q angles were measured on hip dysplasia (HD) and whole limb (WL) view radiographs of each limb between the acetabular rim, mid-point (Q1: patellar center, Q2: femoral trochlea), and tibial tuberosity. Errors of 0.5-2.0 mm at measurement landmarks alone and in combination were modeled to identify the effect on Q angle. The effect of measured Q angles on the medial force exerted on the patella (F MEDIAL) was calculated. Results: The HD position yielded significantly (P < .001) more medial Q angles than the WL position. No significant difference was observed between Q1 and Q2, but Bland-Altman plots indicated they were not equivalent. Intra-and interobserver agreement was substantial. Q2 errors were inherently greater than Q1: the mid-point and tibial tuberosity are the most important sources of Q angle variability. Increasing Q angles significantly increased the exerted F MEDIAL (P < .0001, gradient 1.7%). Conclusions: Measurements are reliable, but Q2 is more prone to error than Q1, and the 2 measurement techniques are not interchangeable. Positional errors must be kept below 1.3 mm (Q1) or 0.8 mm (Q2).
OBJECTIVE To evaluate the effect of center of angulation of rotation (CORA)-based leveling osteot... more OBJECTIVE To evaluate the effect of center of angulation of rotation (CORA)-based leveling osteotomy (CBLO) and hamstring load on stifle stability following cranial cruciate ligament transection (CCLx) and medial meniscal release (MMR). STUDY DESIGN Ex vivo experimental study. SAMPLE POPULATION Cadaver hind limb preparations (n = 7). METHODS After instrumentation, constant quadriceps and gastrocnemius loads with an optional hamstring load in a 3:1:0.6 ratio were applied, and stifles were extended from fully flexed using an electrical motor during fluoroscopic recording. The recording process was repeated after each of CCLx, MMR and CBLO and the extracted landmark coordinates were used for calculation of cranial tibial translation (CTT) and patellar ligament angle (PTA). RESULTS Mean initial tibial plateau angle was 28.1°: post-CBLO the mean was 9.7°. Cranial tibial translation developed from 50° and 75° with CCLx and MMR respectively (p < .04, < .02) without hamstring loading. Hamstring loading mitigated CTT due to CCLx and delayed CTT until 120° for MMR (P < .02) in this model. CBLO prevented CTT, except at 140° without hamstring loading (P = .01). Similar results were seen for PTA, but CBLO curves were parallel to and lower than intact values at all tested angles (P < .04), consistent with induced effective joint flexion. CONCLUSION CBLO to a target tibial plateau angle of 10° largely eliminated CTT induced by CCLx and MMR. Hamstring loads of 20% quadriceps load improved stifle stability in this model. IMPACT Stifle stability following CBLO appears to be multifactorial and depends on meniscal integrity, joint angle, and hamstring strength.
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