Preoperative Tibial Plateau Angle Research Articles

Comparison of the Visibility of Canine Menisci before and after Tibial Plateau Leveling Osteotomy: 3D-Printed Model Study.

The aim of this study was to compare the degree of visibility of the lateral and medial menisci before and after tibial plateau leveling osteotomy (TPLO) on 3D-printed models created after laser scanning of the right tibia with menisci derived from a fresh cadaver of a 4-year-old adult male golden retriever. The models were produced of white polylactic acid, and the menisci were filled with light-curing red resin. The models showed a similar conformation as the natural specimen harvested from the cadaver, maintaining the same length and width, in addition to reproducing the anatomical structures. From the pre- and post-TPLO radiographs, it was possible to identify the anatomical structures corresponding to the tibial plateau. The preoperative tibial plateau angle was 26.2°, and the postoperative one ranged between 4.0° and 5.3° (4.6 ± 0.4°). In the bird's-eye photo, the total number of red pixels in the lateral and the medial meniscus was 2,053,995 and 2,140,939, respectively. Before TPLO, only between 14% and 19% of the entire area of the menisci was visible, and the unhidden part of the entire area of the meniscus before TPLO did not differ significantly between the lateral (16.2 ± 1.6%) and the medial (16.4 ± 1.6%) meniscus (p = 0.351). The visible part of the entire meniscus area increased significantly after TPLO both in the lateral and medial menisci (p < 0.001)-mean difference ± SD of 30.3 ± 4.3% (CI 95%: 27.9%, 32.6%) and 36.4 ± 6.4% (CI 95%: 32.9%, 40.0%), respectively. In conclusion, the intraoperative examination and treatment of dog menisci are easier after TPLO.

The Prevalence and Risk Factors of Contralateral Cranial Cruciate Ligament Rupture in Medium-to-Large (≥15kg) Breed Dogs 8 Years of Age or Older.

The aim of this study was to determine the prevalence of contralateral cranial cruciate ligament rupture (CCLR) in dogs 8 years of age or older, weighing more than or equal to 15 kg at the time of first-side CCLR and to assess associated risks. It is a cross-sectional retrospective study of 831 client-owned dogs METHODS: Medical records of dogs weighing more than or equal to 15 kgs that were more than or equal to 8 years of age at the time of first CCLR diagnosis were reviewed. Data collected included weight, sex, pre-operative tibial plateau angle, co-morbidities, time between diagnosis of first CCLR and diagnosis of contralateral CCLR. Multivariate logistic regression analysis was used to estimate odds ratio. A median follow-up period of over 112.7 months (25th/75th quartiles 75.4/157.7 months) from first CCLR diagnosis was allotted. Eight-hundred thirty-one dogs were identified and included. About 19.1% (159/831 dogs, 95% confidence interval: 16.6-22.0%) of dogs that experience a first-side CCLR at 8 years of age or older will rupture the contralateral side, a median of 12.9 months (25th/75th quartiles 6.5/24.3 months) later. Age (p = 0.003) and breed, Golden Retrievers (p = 0.028) and Labrador Retrievers (p = 0.007), were factors significantly associated with contralateral CCLR. The prevalence of contralateral CCLR in medium-to-large breed dogs more than or equal to 8 years of age old is less than previously reported and the risk decreases as they age. This important information will help guide owners when deciding to pursue surgical stifle stabilization following CCLR in older dogs.

A mismatch of planning and achieved tibial plateau angle in cranial closing wedge surgery: An in silico and clinical evaluation of 100 cases.

(1) To determine whether Oxley's modified cranial closing wedge osteotomy (CCWO) results in a tibial plateau angle (TPA) of 5° in silico, (2) compare in silico to clinical postoperative TPA and (3) determine the impact of ostectomy distalization in silico. Cross-sectional retrospective radiographic in silico study. A total of 100 stifle radiographs; 90 dogs (small ≤25 kg = 84; large >25 kg = 16). Tibial plateau angles were measured preoperatively (TPAPre ), after in silico planning (TPAPlan ), and postoperatively (TPAPost ). Virtual ostectomies were evaluated for plate fit. Postoperative ostectomy position was measured. Virtual ostectomies were performed 5/7.5/10/15 mm from the patellar tendon insertion in 10 dogs from each preoperative TPA category (≤20°/21-25°/ 26-30°/31-35°/>35°). Comparisons for TPAPre , TPAPost , and TPAPlan were made between small and large dogs, and the outcome to the target 5° between TPA categories and ostectomy positions. Mean ± SD TPAPre was 28.6 ± 6.2° and higher in small than large dogs. Mean TPAPlan was 7.6 ± 2.7°. Plate fit was appropriate in all. In silico, TPAs were greater than 5° except for cases with TPAPre > 35°. Median TPAPost was 5.5° (-4-21) and was higher in small (7°) than large (4.5°) dogs. Postoperative ostectomy position was more distal than Oxley's guidelines. When distalized >7.5 mm in silico, the magnitude of under-correction increased. Oxley's modified CCWO did not result in TPA of 5° in most cases. Ostectomy distalization exacerbated under-correction. Current guidelines should be modified to achieve 5° TPA postoperatively.

Preoperative planning using computed tomography in tibial plateau levelling osteotomy: A comparison with conventional radiography.

BackgroundTibial plateau levelling osteotomy (TPLO) is currently one of the most common surgical procedures for the correction of the stifle joint with a ruptured cranial cruciate ligament. TPLO is based on the preoperative tibial plateau angle (TPA); therefore, it is essential to optimise the consistency and repeatability of TPA measurements.ObjectivesThis study aims to compare computed tomography (CT) with conventional radiography in the preoperative planning of TPLO.MethodsThis prospective study included six dogs (12 hindlimbs) and 13 canine cadaveric hindlimbs. In the six beagle dogs, TPAs were measured by three radiologists using digital radiographic and CT images to evaluate the intra‐ and inter‐observer agreement. To evaluate the intra‐observer agreement of the TPA before and after surgery, and the intended angle of the postoperative TPA according to the preoperative planning method, 13 cadaveric hindlimbs were evaluated thrice at random by a single radiologist.ResultsThe intra‐ and inter‐observer intraclass correlation coefficients (ICCs) of the CT method were higher than those of the radiographic method in normal beagle dogs. The intra‐observer ICC of the CT method before and after TPLO was generally higher than that of the radiographic method in the cadaver. However, no significant difference was noted in the evaluation of the intended postoperative TPA according to the preoperative planning method.ConclusionsThe intra‐ and inter‐observer ICCs allowed for easy identification of landmarks required to consistently determine the TPA in the preoperative planning of TPLO based on CT images.

Rock back phenomenon in 32 dogs that underwent tibial plateau levelling osteotomy

The aim of this study was to evaluate the postoperative temporal changes in the tibial plateau angle (TPA) after a tibial plateau levelling osteotomy (TPLO) in dogs. The TPA of thirty-two dogs were measured before surgery (TPA&lt;sub&gt;1&lt;/sub&gt;), immediately after the TPLO (TPA&lt;sub&gt;2&lt;/sub&gt;), and later at the healing of the osteotomy site (TPA&lt;sub&gt;3&lt;/sub&gt;). Three observers carried out three TPA measurements for each patient at the time of the evaluation. TPA changes were observed over the bone healing (2.05 ± 3.05°); however, no statistical significance was noted when comparing TPA&lt;sub&gt;3&lt;/sub&gt; and TPA&lt;sub&gt;1&lt;/sub&gt;. There were no statistical differences in the inter-observer measurements among TPA&lt;sub&gt;1&lt;/sub&gt;, TPA&lt;sub&gt;2&lt;/sub&gt;, and TPA&lt;sub&gt;3&lt;/sub&gt; (P &amp;gt; 0.05). The comparison between the preoperative TPA&lt;sub&gt;1&lt;/sub&gt; and the rock back showed a low positive correlation (S = 4 735.9, P = 0.471 5, r = 0.131 976 9). There was also a low positive correlation between the body weight (kg) and the change in the TPA during the bone healing (S = 4 581.8, P = 0.381, r = 0.160 234 7). Although changes in the TPA have been observed over the time of the bone healing, they were not influenced by the preoperative and postoperative TPA, or by the body weight. The magnitude of the variation in the TPA is not determined by the previous inclination or by the degree of rotation in the plateau.

Prevalence and Risk Factors for Bilateral Meniscal Tears Identified during Treatment for Cranial Cruciate Ligament Disease Via Tibial Plateau Levelling Osteotomy in Dogs.

The aim of this study was to report the prevalence and risk factors of bilateral meniscal tears during a tibial plateau levelling osteotomy (TPLO). Data from 362 dogs that underwent staged or simultaneous TPLO between January 2006 and April 2019 were retrospectively collected. Variables such as breed, sex, weight change and intervals between surgeries were analysed with logistic regression. Preoperative tibial plateau angle, age, cranial cruciate ligament status and body weight were analysed with a generalized linear mixed model. All analyses were performed to assess the likelihood of bilateral meniscal tears versus unilateral tears and no tears. Correlation of meniscal tears between stifles was assessed with Cohen's kappa coefficient. Prevalence of bilateral meniscal tears was 48.0% (95% confidence interval [CI]: 43.0-53.0%). There was moderate agreement of the presence of meniscal tears between stifles (Cohen's kappa coefficient = 0.41, 95% CI: 0.31-0.51).The odds for bilateral meniscal tears were higher for Rottweilers (odds ratio [OR:] 4.5 [95% CI 1.1-30.3], p = 0.033), older dogs (OR: 1.2 [95% CI: 1.1-1.4 per year], p < 0.0001), smaller dogs (OR: 0.98 [95% CI: 0.97-0.99 per 0.45-kg], p = 0.001), stifles with complete cranial cruciate ligament tears (OR: 21.1 [95% CI: 7.1-62.4], p < 0.0001). Contralateral meniscal tears, breed, older age, lower patient weight and complete cranial cruciate ligament tear were significant risk factors for bilateral meniscal tears. Surgeons can use these results to determine prognoses and propensities for meniscal tears in at-risk dogs.

Average Tibial Plateau Angle of 3,922 Stifles Undergoing Surgical Stabilization for Cranial Cruciate Ligament Rupture.

The aim of this study was to report the average tibial plateau angle (TPA) from a large sample of dogs and to determine if breed or gonadectomy had a significant association with abnormal TPA. This was a retrospective case study. Medical records from 2006 to 2015 were reviewed for dogs that were diagnosed with cranial cruciate ligament (CrCL) rupture and underwent dynamic surgical stabilization. Signalment, examination findings, preoperative TPA and surgical report were reviewed. A total of 3,249 dogs underwent CrCL stabilization surgery from 2006 to 2015. Of the 3,249 dogs, 3,054 dogs met the inclusion criteria for a total of 3,922 stifles to be evaluated. The average preoperative TPA was 29° ± 3.7°. Average breed-specific preoperative TPA ranged from 27° to 35.1°, with four breeds having significantly lesser TPA and four breeds significantly greater TPA than the overall mean of dogs. Neutered dogs had a higher TPA of 28.87° ± 3.8° than non-neutered dogs with an average TPA of 26.88° ± 4.0°, p < 0.001. There was not a significant difference in average TPA between females and males, regardless of the neuter status. Our reported preoperative TPA in a large sample of dogs is higher than what has been previously published. In reviewing 3,922 stifles, the average preoperative TPA was 29°. We report the average preoperative TPA in specific breeds and report that neutered dogs have a significantly higher TPA than intact dogs. This updated information may guide clinicians in management decisions regarding treatment for CrCL rupture.

Fibular osteotomy to facilitate proximal tibial rotation during tibial plateau leveling osteotomy.

To identify factors that restrict proximal tibial rotation during tibial plateau leveling osteotomy (TPLO) and report on the outcome of concurrent fibular osteotomy (TPLO-FO). Retrospective case-control study. Dogs undergoing TPLO-FO (n = 23) and dogs undergoing routine TPLO (n = 49). Medical records and radiographs of dogs that had undergone TPLO-FO were reviewed. Data that were collected included signalment, preoperative tibial plateau angle (TPA), mechanical medial proximal tibial angle (mMPTA), postoperative and recheck TPA and mMPTA, ratio of fibular width to tibial width (FW:TW), presence of tibiofibular synostosis, tibial osteotomy location, and use of additional implants. The odds of exhibiting rotational constraints requiring FO during TPLO were 62-fold greater in dogs with tibiofibular synostosis than in dogs without synostosis. Dogs with FW:TW greater than 0.24 were 7.8-fold more likely to exhibit rotational constraints. After TPLO-FO, the postoperative increase in TPA was greater after single-plate fixation (mean, 5.4 ° ± 4.5 °) compared with fixation with 2 plates (mean, 1.4 ° ± 0.6 °). Proximal tibiofibular synostosis and a relatively wide fibula restricted tibial plateau rotation. In these dogs, concurrent fibular osteotomy allowed adequate rotation. Adjunct plate fixation limited loss of rotation after TPLO-FO. Successful TPLO relies on adequate rotation of the proximal tibial segment. Fibular osteotomy and adjunct plate fixation are recommended to achieve and maintain adequate rotation of the osteotomized tibia in dogs with rotational constraints.

Relationship between Tibial conformation, cage size and advancement achieved in TTA procedure

BackgroundPrevious studies have suggested that there is a theoretical discrepancy between the cage size and the resultant tibial tuberosity advancement, with the cage size consistently providing less tibial tuberosity advancement than predicted. The purpose of this study was to test and quantify this in clinical cases. The hypothesis was that the advancement of the tibial tuberosity as measured by the widening of the proximal tibia at the tibial tuberosity level after a standard TTA, will be less than the cage sized used, with no particular cage size providing a relative smaller or higher under-advancement, and that the conformation of the proximal tibia will have an influence on the amount of advancement achieved.ResultsOne hundred sixty-four dogs met the inclusion criteria. The mean percentage under-advancement was 15.5%. All dogs had an advancement less than the stated cage size inserted. An association between the proximal tibial tuberosity angle (increased in cases with low patellar tendon insertion), and percentage under-advancement was found, with an increase of 0.45% under-advancement for every 1 degree increase in angle a (p = 0.003). There was also evidence of a difference between the mean percentage under-advancement in breeds (p = 0.001) with the Labrador having the biggest under-advancement. Cage size (p = 0.83) and preoperative tibial plateau angle (p = 0.27) did not affect under-advancement.ConclusionsThe conformation of the tibial tuberosity and therefore the relative cage positioning have an impact on mean percentage under-advancement of the tibial tuberosity after standard TTA. In all evaluated cases, the advancement of the tibial tuberosity was less than intended by the cage size selected.

A novel jig arm to measure tibial plateau angle during tibial plateau leveling osteotomy.

To determine the ability of a novel device attached to the proximal tibial plateau leveling osteotomy (TPLO) jig pin to accurately predict intraoperative change in tibial plateau angle (TPA). In vitro cadaveric study. Left hindlimbs of adult dogs (n = 9). A modified Slocum tibial plateau leveling (TPL) jig with the Rotational Osteotomy Measuring Arm (ROMA) was placed on the tibia and a radial TPLO osteotomy was performed. Based on preoperative radiographic TPA measurements, the proximal segment was rotated using the traditional method of marking points on the osteotomy a specified distance apart. After rotation, the predicted TPA was recorded based on the ROMA. Postoperative TPA was measured on radiographs. The ability of the ROMA to predict postoperative TPA was compared to that of the traditional method. The average final TPA achieved with the traditional method was 6.4° (range, 3.0-10.0°). The ROMA predicted a final TPA of 5.8° (range, 3.8-10.1°). No significant difference was found between the TPA predicted based on the traditional method and ROMA method. The ROMA may be an alternative to the traditional method of measuring proximal segment rotation during TPLO procedure. Performing a TPLO with the ROMA may accurately predict the postoperative TPA while eliminating the need for measuring chord length, making reference marks, or referencing TPA charts for various osteotomy blade sizes.

Radiographic evaluation and comparison of the patellar ligament following tibial plateau leveling osteotomy and tibial tuberosity advancement in dogs: 106 cases (2009-2012).

OBJECTIVE To radiographically evaluate and compare changes in the patellar ligament of dogs following tibial plateau leveling osteotomy (TPLO) and tibial tuberosity advancement (TTA). DESIGN Retrospective case series. ANIMALS 106 dogs that underwent TPLO (n = 59) or TTA (n = 47) for unilateral rupture of the cranial cruciate ligament at a private veterinary hospital from August 2009 through September 2012. PROCEDURES Medical records were reviewed to collect information on dog signalment, surgical procedure, whether arthrotomy had been performed, pre- and postoperative measurements of patellar ligament angle (PLA) and tibial plateau angle (TPA), and preoperative and follow-up measurements of patellar ligament thickness. RESULTS For dogs that underwent TTA, thickening of the distal portion of the patellar ligament was identified radiographically in 43 (92%) dogs at the first follow-up examination and 36 (77%) at the second follow-up examination. For dogs that underwent TPLO, these numbers were 57 (97%) and 54 (92%), respectively. A significant decrease in patellar ligament thickness was identified between the first and second follow-up examinations for TTA but not TPLO. Mean ± SD PLA following TTA was 89.46 ± 5.54°, representing a mean difference from the preoperative PLA of 11.86 ± 5.3°; following TPLO, mean TPA was 12.61 ± 4.03°, representing a mean difference from the preoperative TPA of 16.74 ± 7.13°. CONCLUSIONS AND CLINICAL RELEVANCE Patellar ligament thickening occurred following TPLO and TTA in dogs. The clinical relevance of this thickening remains unknown.

Tibial plateau levelling osteotomy in 69 small breed dogs using conically coupled 1.9/2.5 mm locking plates. A clinical and radiographic retrospective assessment.

To report clinical experiences with the tibial plateau levelling osteotomy (TPLO) procedure in small breed dogs with cranial cruciate ligament (CCL) disease using specific, conically coupled, 1.9/2.5 mm locking plates and evaluating short-term complications and outcome. Medical records of small breed dogs (<15 kg) that underwent TPLO using 1.9/2.5 mm locking plates were reviewed retrospectively. The preoperative, postoperative and six to eight weeks postoperative tibial plateau angle (TPA) measurements were determined from the radiographic images. Lameness evaluation was assessed subjectively preoperatively and six to eight weeks postoperatively. Sixty-nine small breed dogs (n = 79 stifles) were included in the study. Mean (± SD) preoperative TPA was 29.0 ± 3.4°, postoperative TPA was 5.8 ± 2.5°, and six to eight weeks postoperative TPA was 7.3 ± 4.1°. Sixteen complications occurred in 12 out of 79 TPLO procedures: three were intra-operative (intra-articular screw placement) and 13 were postoperative complications, of which nine were identified as minor complications not requiring surgical reintervention, and four as major complications requiring additional surgical intervention, including tibial tuberosity fracture (n = 1), osteomyelitis (n = 1), screw failure (n = 1), and plate breakage (n = 1). Lameness scores by clinical assessment reduced from a median value of 3/4 preoperatively to 1/4 at six to eight weeks postoperatively. 1.9/2.5 mm locking plates appear to be a valid choice of implant for the stabilization of unilateral TPLO in small breed dogs.

Effect of tibial plateau levelling osteotomy on patellar tendon angle: a prospective clinical study.

To evaluate the effect of the tibial plateau levelling osteotomy (TPLO) procedure on the patellar tendon angle (PTA) in dogs with naturally occurring cranial cruciate ligament rupture. Prospective observational clinical study. Dogs with naturally occurring CrCL rupture that had a TPLO performed (n = 40). Preoperative tibial plateau angle (TPA) and PTA were measured on radiographic images of affected stifle joints at 90° and standing angle (135°) respectively. The TPA and PTA were measured after TPLO was performed. Regression analysis was performed to evaluate the effect of preoperative TPA and PTA and postoperative TPA on postoperative PTA. Linear regression analysis was performed to evaluate the correlation between postoperative TPA and PTA. The mean (± SD) preoperative TPA and PTA were 26.5 ± 3.8° and 105.7 ± 3.8° respectively. The postoperative TPA and PTA values were 7.6 ± 3.3° and 91.4 ± 5.5°, respectively. Regression analysis showed that higher preoperative PTA and postoperative TPA are associated with a larger difference between the postoperative PTA and 90°. There was a positive correlation between postoperative TPA and PTA. The TPLO procedure alters the PTA to 90° in dogs with cranial cruciate ligament rupture similar to tibial tuberosity advancement (TTA). The TPLO may provide dynamic stability to the cranial cruciate deficient stifle by altering the TPA relative to the patellar tendon and creating a PTA of 90°. The biomechanical principle and mechanism of action of TPLO may be similar to TTA.

Radiographic outcome and complications of tibial plateau leveling osteotomy stabilized with an anatomically contoured locking bone plate

To evaluate the short-term clinical performance of an anatomically pre-contoured, locking plate in dogs undergoing tibial plateau leveling osteotomy (TPLO) for cranial cruciate ligament (CrCL) disease. Prospective, multi-center clinical study. Dogs (n = 56) undergoing TPLO. Signalment and operative data were recorded. Preoperative, postoperative, and follow-up tibial plateau angle (TPA) were measured from radiographic images. Intraoperative and postoperative complications were recorded; the latter were categorized as minor if additional surgery was not necessary, and major if surgery was needed to resolve the complication. Bone healing was scored and change in tibial plateau angle (TPACH ) between postoperative and follow up radiographic images was calculated. Mean (± SD) preoperative TPA was 28.6 ± 3.8°, and mean postoperative TPA was 4.8 ± 1.9°. Four intraoperative complications (7.1%) including 2 cases of intra-articular screw placement, 3 minor postoperative complications (5.4%), and no major or catastrophic postoperative complications occurred. Median bone healing grade was 4/4 (excellent union >75% healing). Mean TPACH was 0.15 ± 1.32°. Use of this anatomically contoured, locking TPLO plate by experienced surgeons is associated with accurate tibial plateau leveling, reliably excellent bone union at follow-up exam, minimal TPACH , and a lower complication rate than previously reported. Confining contouring to the distal shaft of the plate ensures there is precise apposition to the tibial diaphysis and mitigates the risk of intra-articular screw placement.

Stabilization of the CORA Based Leveling Osteotomy for Treatment of Cranial Cruciate Ligament Injury Using a Bone Plate Augmented With a Headless Compression Screw

To report the effectiveness of a bone plate/headless compression screw (HCS) construct in preventing tibial plateau angle (TPA) shift postoperatively and to describe radiographic healing of the osteotomy. Case series. Dogs (n = 31). Records of dogs diagnosed with cranial cruciate ligament (CCL) injury treated with the center of rotation of angulation (CORA) based leveling osteotomy (CBLO) stabilized with a bone plate augmented with a HCS were reviewed. Breed, age, weight, and gender were recorded. Radiographs were reviewed for determination of preoperative tibial plateau angle (PreTPA), postoperative TPA (PostTPA), patellar tendon angle (PTA) postoperatively, and TPA at final evaluation (FinalTPA). Difference between PostTPA and FinalTPA was used to define any TPA shift. Radiographic healing at final evaluation was graded based on a 5-point scale. Mean time to final recheck was 88 days (range 49-237 days) with mean ± SD PreTPA = 28.6 ± 4.8°; PostTPA = 9.2 ± 2.2°; FinalTPA = 9.7 ± 2.6°; and TPA Shift = 0.52 ± 1.61°. There was no significant difference between PostTPA and FinalTPA (P = .084, power > 0.80). Mean postoperative PTA was 89.9 ± 1.7°. There were 2 implant related complications; 1 HCS migration and 1 HCS failure. Stabilization of the CBLO using a bone plate augmented with a HCS was effective in maintaining PostTPA and achieving satisfactory radiographic healing.

Comparison of Tibial PA, Bone Healing, and Intra‐articular Screw Placement using Conventional Nonlocked Application of Surgeon‐Contoured versus Locked Application of Precontoured TPLO Plates in Dogs

To determine the influence of conventional nonlocked application of surgeon-contoured (NL-SXc) and locked-hybrid application of precontoured (L-Pc)- TPLO plates on the tibial plateau angle (TPA) immediately postoperatively and longterm after tibial plateau leveling osteotomy (TPLO) in dogs as well as to evaluate their influence on the incidence of intra-articular screw placement and bone healing. Retrospective, cross-sectional, clinical study. Dogs (n = 101) with cruciate ligament insufficiency that had TPLO. Collected data included signalment, plate size/type, preoperative (PreTPA), postoperative (PostTPA), and recheck TPA (ReTPA). Tibial plateau rotation achieved during surgery (RotaTPA = PreTPA-PostTPA) and TPA shift during healing (ShiftTPA = ReTPA-PostTPA) were calculated. Radiographic evidence of stability and time to radiographic recheck were recorded. Variables were compared by plate type using a 2-sample t-test or χ(2) as appropriate (significance at P < .05). Median time to radiographic follow-up was 75 days (range, 43-2815 days). The remaining data are reported as means. Forty-two stifles had NL-SXc, 59 stifles had L-Pc. PreTPA of NL-SXc and L-Pc was 28.3° and 29.1°, respectively (P = .22). PostTPA (13.2° and 7.9°), RotaTPA (15.0° and 21.2°) and ReTPA (14.9° and 10.3°) for NL-SXc and L-Pc, respectively, were all significantly different (P< .0001). ShiftTPA for these constructs (1.7° and 2.4°, respectively) was not significantly different (P = .25), and 92.1% of dogs were considered to have radiographically stable osteotomies at last recheck. A higher degree of tibial plateau rotation was achieved and maintained in osteotomies with L-Pc. There was no significant difference in ShiftTPA or radiographic osteotomy stability between constructs.

Risk Factors Associated with Fibular Fracture After Tibial Plateau Leveling Osteotomy

To determine the incidence of, and risk factors for, fibular fracture after tibial plateau leveling osteotomy (TPLO) in dogs. Case series. TPLO (n=168) on 142 dogs. Medical records (January 2006-September 2007) and radiographs of all dogs that had TPLO were reviewed. Data retrieved were breed, sex, age, weight, type of plate, use of a jig, time to recheck, preoperative tibial plateau angle (TPA), immediate postoperative TPA, and presence or absence of fibular fracture. Fibular fractures occurred in 5.4% TPLOs. Body weight, change in TPA, and preoperative TPA were significantly higher in dogs with fibular fracture. TPLO without use of a jig was significantly associated with fibular fracture. Age, postoperative TPA, and plate type were not significantly associated with fibular fracture. Fibular fracture is uncommon after TPLO. Risk factors are increased body weight, greater preoperative TPA, greater change in TPA, and TPLO performed without a jig. All fractures occurred during convalescence. Owners should be warned of potential complications and risk factors associated for fibular fracture after TPLO.

The Effect of Tibial Plateau Angle on Ground Reaction Forces 4–17 Months After Tibial Plateau Leveling Osteotomy in Labrador Retrievers

To assess the relationship between postoperative tibial plateau angle (TPA) and ground reaction forces (GRFs) in Labrador Retrievers at least 4-months after tibial plateau leveling osteotomy (TPLO) surgery. A retrospective longitudinal study. Thirty-two Labrador Retrievers with unilateral cranial cruciate ligament disease that had TPLO and concurrent meniscal surgery. TPA and GRFs were measured pre- and > or = 4 months postoperatively. Preoperative GRFs, preoperative TPA, duration of injury, postoperative TPA and degree of rotation were each compared with postoperative GRFs using correlation analysis. Dogs were also grouped by postoperative TPA and compared using 1-way analysis of variance (ANOVA). Postoperative function was compared with meniscal release/meniscectomy, patient age, sex, body weight and follow-up time using ANOVA. No significant relationship was found between preoperative GRFs, preoperative TPA, duration of injury, postoperative TPA, degree of rotation, or meniscal release/meniscectomy and postoperative function. Mean preoperative GRFs for all dogs were 28.8 +/- 9.5 for peak vertical force (PVF) and 9.3 +/- 3.1 for peak vertical impulse (VI). Mean postoperative GRFs for all dogs were 40.4 +/- 5.0 for PVF and 14.1 +/- 1.9 for VI. No statistically significant relationship was found between postoperative TPA and GRFs after TPLO > or = 4 months after surgery, where the postoperative angle was between 0 and 14 degrees. No significant relationship was found between the preoperative TPA and postoperative function. Limb function in Labrador Retrievers was not affected by postoperative TPA and re-operation for cases with a postoperative TPA between 0 and 14 degrees is not recommended.