Change in tibial plateau angle after tibial plateau leveling osteotomy in dogs

OBJECTIVE: To determine the change in tibial plateau angle (TPA) during healing after tibial plateau leveling osteotomy (TPLO) performed for cranial cruciate ligament insufficiency in dogs and to examine factors that may be associated with the change. STUDY DESIGN: Retrospective study. STUDY POPULATION: One hundred and forty-nine canine stifles after TPLO procedure. METHODS: Records of dogs that had TPLO were reviewed. Patient age, weight, sex, breed, pre- and postoperative TPA, recheck TPA, time to recheck, type of implant used, and radiographic evidence of healing were analyzed. RESULTS: Mean time to recheck evaluation was 46 days (range, 28-65 days). Mean difference between immediate postoperative and recheck TPA measurements was 1.5 degrees (range, -3 to 9 degrees). Recheck TPA was a significantly greater (numerically higher) than immediate postoperative TPA (P<.0001). There was no significant effect of patient weight, type of plate used, or healing status of the osteotomy at the time of recheck. No correlation between pre- or postoperative TPA angles and change in TPA angle was detected. CONCLUSIONS: TPA changes during osteotomy healing after TPLO, but factors influencing this change were not identified. CLINICAL RELEVANCE: TPA may increase during healing after TPLO despite apparently adequate osteotomy fixation. The clinical relevance of this increase is unknown but is likely minimal.     

Use of the proximal portion of the tibia for measurement of the tibial plateau angle in dogs

OBJECTIVE: To determine whether the canine tibial plateau angle (TPA) can be accurately measured from lateral radiographic views of the stifle joint that include only the proximal portion of the tibia. SAMPLE POPULATION: 282 lateral radiographic views of the stifle joint from 128 dogs. PROCEDURE: 236 radiographs were obtained from 102 dogs with no stifle joint disease, and 46 were obtained from 26 dogs with cranial cruciate ligament rupture. Radiographs were digitized. Tibial plateau angles were determined by measuring the angle between the intersection of the tibial plateau slope line and perpendiculars to 4 tibial axes. The gold standard TPA was based on a reference axis that used the entire length of the tibia and was determined by the line connecting the midpoint of the tibial intercondylar eminence and the center of the talus. Tibial plateau angle1, TPA2, and TPA3 were based on tibial axes that were determined by use of only the proximal portion of the tibia. RESULTS: TPA determined on the basis of the shortest proximal reference axis (TPA1) was not accurate. However, as the length of the reference axis increased, reliability of the TPAs obtained from proximal reference axes improved, and their correlations with the gold standard TPA increased (r = 0.78, 0.86, and 0.92 for TPA1, TPA2, and TPA3, respectively). Equations obtained by regression analysis allowed estimation of the gold standard TPA with some degree of accuracy. CONCLUSIONS AND CLINICAL RELEVANCE: Use of a proximal reference axis to calculate TPA may be an alternative to a calculation based on the full-length axis.     

Sequential measurements of the tibial plateau angle in large-breed, growing dogs

OBJECTIVES: To determine the earliest age that canine tibial plateau angles (TPAs) can be reliably measured and determine whether TPAs change during long bone growth. ANIMALS: 10 Labrador Retrievers and 20 Labrador Retriever-hound crossbreeds. PROCEDURE: Stifle joints were radiographed every 2 months from 8 weeks of age to radiographic closure of the tibial physes. Four examiners radiographically evaluated TPA, physeal closure status (ie, complete or incomplete) of the proximal and distal tibial physis, and whether anatomic TPA measurement landmarks were sufficiently visible (LSV) or insufficiently visible (LIV) for accurate measuring. Linear regression analysis was performed to detect change in TPAs over time. Mean ages with 95% confidence intervals (CIs) were determined for dogs with radiographs classified as LIV and LSV. RESULTS: TPAs did not change from 90 days of age to physeal closure. Mean age for dogs with radiographs classified as LIV was 70.2 days (95% CI, 68.12 to 72.28 days), with no dog with LIV radiographs over 81 days of age. Mean age for dogs with radiographs classified as LSV was 85.5 days (CI, 76.73 to 94.27 days). CONCLUSIONS AND CLINICAL RELEVANCE: TPAs in Labrador Retrievers and Labrador Retriever-hound crossbreeds can be measured accurately after 90 days of age, and earlier attempts to measure result in falsely low TPA measurements. Measuring TPAs in growing dogs may allow earlier detection of premature physeal closures. As more is learned about the role of theTPA in cranial cruciate ligament injury, early treatment may be possible for growing dogs with cruciate ligament injuries and excessive tibial slope.     

Influence of limb positioning and measurement method on the magnitude of the tibial plateau angle

OBJECTIVE: To evaluate the effect of limb positioning and measurement technique on the magnitude of the radiographically determined tibial plateau angle (R-TPA). STUDY DESIGN: In vitro study, R-TPA was determined by 6 blinded observers and image measurement software. ANIMALS: Five canine cadaver hind limbs. METHODS: The legs were positioned on a custom-made positioning device simulating a radiographic tabletop technique in lateral recumbency. True lateral positioning was defined by superimposition of femoral and tibial condyles on the radiographic projection. Radiographs were taken while the specimens were relocated in a proximal, distal, caudal, and cranial direction with respect to the radiographic beam. For each specimen, 25 different radiographic views were obtained and 6 blinded observers determined the radiographic TPA using 2 different methods. The conventional method used precise anatomic landmarks to determine the tibial plateau. To simulate osteoarthritic changes complicating identification of these landmarks, the tangential method estimated the tibial plateau as the tangent to the central portion of the tibial plateau. After periarticular soft tissue dissection the anatomic tibial plateau angle (A-TPA) was determined. The A-TPA and the R-TPA were compared. RESULTS: The R-TPA significantly decreased as limb position with respect to the X-ray beam changed from cranial proximal to caudal distal. The maximal mean radiographic R-TPA difference was 3.6 degrees with the first and 5.7 degrees with the second method. Regardless of the method used there was no significant difference between A-TPA and R-TPA in the true lateral position. In the peripheral positions, however, significant differences between anatomic and radiographic TPA were seen. CONCLUSIONS: Limb positioning influenced the radiographic appearance of the tibial plateau and the magnitude of the measured TPA. Cranial and proximal positioning of the limb relative to the X-ray beam leads to overestimation whereas caudal and distal positioning leads to underestimation of the TPA. CLINICAL RELEVANCE: True lateral positioning of the tibia defined by superimposition of the femoral and tibial condyles should be used for accurate TPA determination before tibial plateau leveling osteotomy.     

Relationship between age and tibial plateau angle in dogs with cranial cruciate rupture

The pathogenesis of cranial cruciate ligament (CCL) rupture remains controversial, and its relationship to tibial plateau angle is unknown. In this study, the tibial plateau angle was measured in 200 large-breed dogs diagnosed with CCL rupture. Correlation analyses were performed to determine whether the age at the time of CCL rupture and the tibial plateau angle were related. While these two values were inversely correlated, the relationship was not strong enough to explain the frequency of CCL rupture in young, large-breed dogs. There was no statistically significant correlation between age at the time of CCL rupture and tibial plateau angle.     

Digital measurement of radiographic tibial plateau angle. A comparison to measurement on printed digital images.

Pre-operative digital radiographs from 50 dogs undergoing a tibial plateau leveling osteotomy were evaluated. Tibial plateau angles were measured directly on printed films and measured on digital images using two different commercial DICOM viewers. The radiographs were scored for osteoarthritis and positioning. Using pooled results, the mean TPA from the digital images employing Web1000 (26.47 degrees +/- 3.90) was significantly higher then the mean TPA using film radiographs (25.41 degrees +/- 3.51), or IQ-View Pro (25.48 degrees +/- 3.89). There was not a significant difference between mean TPA using radiographs or IQ-view. Digital TPA measurement using built-in angle calipers in the clinical setting is a valid technique compared to measurements from film radiographs, and produces reproducible results. However, before changing to digital measurements, the chosen software programme should be validated against measurements using film radiographs to determine the magnitude of differences.     

Tibial plateau symmetry and the effect of osteophytosis on tibial plateau angle measurements

A novel technique was developed to estimate the caudal medial tibial plateau landmark in the face of osteophytosis to improve accuracy in tibial plateau angle measurements. Using this technique, tibial plateau angles were evaluated in 31 normal dogs before and 8 months after right cranial cruciate ligament transection. There was no significant difference in mean tibial plateau angle before or after induction of osteophytosis. Additionally, it was determined that 90% of dogs had a difference of =2 degrees between right and left tibial plateau angles, which was considered symmetrical.     

Pressure distributions on the medial tibial plateau after medial meniscal surgery and tibial plateau levelling osteotomy in dogs

OBJECTIVE: To evaluate the effect of medial meniscal release (MMR) and medial, caudal pole hemimeniscectomy (MCH) on pressure distribution in the cranial cruciate ligament (CCL) deficient canine stifle, and with tibial plateau levelling osteotomy (TPLO). ANIMALS: Twelve adult dogs. METHODS: In experiment one, six pairs of cadaveric canine stifles with an intact CCL were axially loaded with a servo-hydraulic material testing machine and pressure distributions were mapped and quantified using pressure sensitive films. Axial loading of each joint was then repeated following MMR, and again after MCH. In experiment two, six pairs of cadaveric canine stifles with or without TPLO were tested before and after CCL transection, and each MMR and MCH procedure using the same methods of experiment 1. RESULTS: In experiment one, MMR and MCH had significant effects on the pressure distribution resulting in a 2.5-fold increase in the percentage of surface area with pressure higher than 10 MPa. In experiment two, CCL transection resulted in a significant change in pressure distribution only in the stifle without TPLO (P<0.05). Both MMR and MCH resulted in a 1.7-fold increase in the percentage of area with peak pressure in the stifle with TPLO (P<0.05). CONCLUSIONS: Meniscal surgery results in a change in pressure distribution and magnitude within the medial compartment of the stifle. CLINICAL RELEVANCE: Compromised function of the meniscus by either MMR or MCH result in stress concentration which may predispose to osteoarthritis.     

Intra- and interobserver measurement variability of tibial plateau slope from lateral radiographs in dogs

Measurement of the tibial plateau slope from lateral hind-limb radiographs is a preoperative requirement when performing tibial plateau leveling osteotomy (TPLO) for repair of the cruciate-deficient stifle in dogs. Two measurements of the tibial plateau slope in 312 stifles of 156 dogs were taken from lateral radiographs by each of three observers with varying degrees of experience in the measurement method. Intraobserver variability was +/-3.4 degrees, and interobserver variability was +/-4.8 degrees. No significant differences were identified for the intraobserver measurements; however, in evaluating interobserver variability, a significant difference was found between the inexperienced observer and the two experienced observers.     

Risk factors for excessive tibial plateau angle in large-breed dogs with cranial cruciate ligament disease

OBJECTIVE: To identify risk factors for development of excessive tibial plateau angle (TPA) in large-breed dogs with cranial cruciate ligament disease (CCLD). DESIGN: Case-control study. ANIMALS: 58 dogs with excessive TPAs (ie, TPA >or= 35 degrees ; case dogs) and 58 dogs with normal TPAs (ie, TPA or= 35 degrees in both limbs were 13.6 times (95% confidence interval, 2.72 to 68.1) as likely to have been neutered before 6 months of age as were control dogs with TPA 相似文献   

Complications of tibial plateau levelling osteotomy in dogs

The tibial plateau levelling osteotomy (TPLO) is one of the most common surgical procedures used to treat cranial cruciate ligament disease in dogs. Complications occurring during or after TPLO can range in severity from swelling and bruising to fracture and osteomyelitis. Ten to 34% of TPLO surgical procedures are reported to experience a complication and approximately two to four percent require revision surgery to address a complication. Although the risk factors for many complications have not been fully assessed, the best available evidence suggests that complications of TPLO can be reduced with increased surgeon experience, careful surgical planning, and accurate execution of the surgical procedure. Identification of known or suspected risk factors and intra-operative technical errors allow subsequent action to be taken that is aimed at decreasing postoperative morbidity. There is a need for prospective studies with consistent data reporting in order to fully reveal the incidence risk factors for complications associated with TPLO.     

Observer variability of tibial plateau slope measurement in 40 dogs with cranial cruciate ligament-deficient stifle joints

OBJECTIVE: To determine (1) the inter- and intraobserver variability in measurement of tibial plateau angle (TPA), (2) whether this inter- and intraobserver variability is related to the characteristics of the dog (age, size, and amount of degenerative joint disease [DJD]) and the experience level of the observer, and (3) the extent of any relationship between interobserver variability of TPA and the variability of the observers' selection of the specific cranial and caudal points along the tibial plateau. STUDY DESIGN: Examination of tibial radiographs of 40 dogs clinically affected with a cranial cruciate ligament (CrCL)-deficient stifle joint. METHODS: Eleven different observers, divided into 3 groups based on their level of experience with the tibial plateau leveling osteotomy (TPLO) technique, measured the TPA on all 40 radiographs on 5 different occasions. The degree of DJD present in the stifle joint was independently graded as an overall measure and then again as it specifically related to the cranial and caudal points along the tibial plateau. The total observed variabilities of the TPA were assessed with reference to interobserver differences, intraobserver differences, and among the groups of observers with respect to the different dog characteristics. Finally, the specific points selected on the radiographs were reexamined to determine whether any variability was present in cranial and caudal point selection. RESULTS: The interobserver standard deviation of the TPA measurements for each dog was 0.8 degrees, and the intraobserver standard deviation was 1.5 degrees. The TPA measurements obtained by the 11 observers differed significantly from each other (P <.001); however, there was no significant difference of TPA among the different groups of observers (P =.67). There was no significant correlation observed between either the inter- or intraobserver variability and the dog characteristics. Specific point data and their relationship to the various variables of dog characteristics and inter- and intraobserver TPA variability revealed significant correlations only to the amount of DJD present at the caudal point (P =.001). CONCLUSIONS: Interobserver variation, but no significant group variation, was present. Overall DJD did not appear to be related to the variability in TPA angle measurement. Most of the interobserver variability was attributable to variability in horizontal point selection at both the cranial and caudal points and vertical point selection at the caudal point. It appears that degenerative changes that specifically obscure the points on the tibial plateau, especially at the caudal point, are responsible for most of the interobserver variation. CLINICAL RELEVANCE: The desired postoperative TPA of 5 degrees is dependent on a precise initial measure of TPA preoperatively. This study indicates that there is statistically significant interobserver variability with measurement of TPA, which, therefore, can result in a similar amount of variability with the final tibial plateau slope obtained postoperatively.     

Comparison of radiographic assessments of the tibial plateau slope in dogs

OBJECTIVES: To evaluate the accuracy of 2 radiographic methods used to assess tibial plateau slope (TPS) in dogs and evaluate effects of film digitization and radiographic beam placement on TPS measurements. SAMPLE POPULATION: 16 hind limbs from dog cadavers weighing > 20 kg. PROCEDURES: Radiographs of tibiae were made with the radiographic beam centered over the stifle joint and midshaft of the tibia. Tibiae were collected, the femorotibial contact area was determined, and slope of the medial tibial condyle in relation to the tibial shaft was measured. Radiographs were digitized. Slope of the medial tibial condyle was measured on printed and digitized radiographs read in random order by 6 examiners unaware of anatomic measurements. Three examiners used a conventional measuring technique, and 3 examiners used an alternative measuring technique. RESULTS: Anatomic measurements were significantly higher than radiographic measurements made by use of the conventional interpretation method but did not differ from radiographic measurements made by use of the alternate method. Measurements from printed radiographs were lower than measurements from digitized radiographs for the 4 most experienced examiners. CONCLUSIONS AND CLINICAL RELEVANCE: Measurements made by use of a line tangential to the cranial, linear portion of the medial tibial condyle at the femorotibial contact point were accurate measurements of the anatomic TPS. Measurements made by use of the conventional TPS measurement method underestimated the anatomic TPS. Measurements made on digitized radiographs were typically more accurate than measurements made on printed radiographs.     

The possible role of the tibial plateau angle for the severity of osteoarthritis in dogs with cranial cruciate ligament rupture

The purpose of this study was to determine factors correlated with the severity of radiographic osteoarthritis (OA) scoring in dogs with cranial cruciate ligament rupture (CrCLR). Three radiographs of stifle joints (craniocaudal, mediolateral, and mediolateral radiograph with 90 degree flexion of the stifle and tarsal joints) were obtained from 36 dogs with CrCLR (Clinical group) and from 22 dogs without stifle joint disease (Control group). Information about these dogs was collected from the owners and from medical records. Radiographic OA scores in each dog in the clinical group were determined from radiographs using a numeric grading system previously reported. The tibial plateau angle (TPA) in each dog in both groups was measured on mediolateral radiographs with 90 degree flexion of the stifle and tarsal joints. The Mann-Whitney's U test was used for comparing variables between the clinical group and the control group, and Spearman's rank correlation test was used for evaluating correlations between radiographic OA scores and variables in the clinical group. No significant differences were detected between the clinical group and the control group for any of the variables. There were two positive correlations; one between the radiographic OA score and TPA (r=0.395, p=0.014); and the other between body weight and OA score (r=0.399, p=0.013) in the clinical group. Our results indicate that body weight and TPA could affect the severity of the radiographic OA score in dogs with CrCLR.