Target Trial Emulation: Does surgical versus non-surgical management of cranial cruciate ligament rupture in dogs cause different outcomes?

Target trial emulation applies design principles from randomised controlled trials to the analysis of observational data for causal inference and is increasingly used within human epidemiology. Using anonymised veterinary clinical data from the VetCompass Programme, this study applied the target trial emulation framework to determine whether surgical (compared to non-surgical) management for cranial cruciate ligament (CCL) rupture in dogs causes improved short- and long-term lameness and analgesia outcomes. The emulated target trial included dogs diagnosed with CCL rupture between January 1, 2019 and December 31, 2019 within the VetCompass database. Inclusion in the emulated trial required dogs aged ≥ 1.5 and < 12 years, first diagnosed with unilateral CCL rupture during 2019 and with no prior history of contralateral ligament rupture or stifle surgery. Dogs were retrospectively observed to have surgical or non-surgical management. Informed from a directed acyclic graph derived from expert opinion, data on the following variables were collected: age, breed, bodyweight, neuter status, insurance status, non-orthopaedic comorbidities, orthopaedic comorbidities and veterinary group. Inverse probability of treatment weighting (IPTW) was used to adjust for confounding, with weights calculated based on a binary logistic regression exposure model. Censored dogs were accounted for in the IPTW analysis using inverse probability of censoring weighting (IPCW). The IPCWs were combined with IPTWs and used to weight each dog's contribution to binary logistic regression outcome models. Standardized mean differences (SMD) examined the balance of covariate distribution between treatment groups. The emulated trial included 615 surgical CCL rupture cases and 200 non-surgical cases. The risk difference for short-term lameness in surgically managed cases (compared with non-surgically managed cases) was -25.7% (95% confidence interval (CI) -36.7% to -15.9%) and the risk difference for long-term lameness -31.7% (95% CI -37.9% to -18.1%). The study demonstrated the application of the target trial framework to veterinary observational data. The findings show that surgical management causes a reduction in short- and long-term lameness compared with non-surgical management in dogs.

Cadaveric comparison of two techniques for intraoperative placement of tibial plateau levelling osteotomies in dogs.

BACKGROUND: Both tibial tuberosity fractures and deviation from the planned postoperative tibial plateau angle have been associated with poor centring of tibial plateau levelling osteotomies (TPLOs). The aim of this cadaveric study was to compare two techniques for centring the osteotomy and preserving the tibial tuberosity width (TTW). METHODS: Stifle radiographs were obtained from 20 limbs of 10 dogs. TPLO was planned on each stifle, and a two-wire technique (TWT) and a technique using the medial collateral ligament (MCL) as an intraoperative landmark were planned. The techniques were executed and marked with radiopaque pins. Further radiographs were obtained and analysed. RESULTS: On average, TWT resulted in a 20.4% increase in TTW and medial collateral ligament technique (MCLT) resulted in a 13.4% decrease. Expressed as a percentage of the radial saw size, the average error in the centring of the osteotomy arising from the TWT was 13.4% and that from the MCLT was 14.2%. LIMITATIONS: This study had a small sample size and involved a single surgeon. CONCLUSION: Neither technique reliably identified the desired centre of the osteotomy, and both had a similar magnitude of error. MCLT resulted in reduced TTW, while TWT resulted in increased TTW. A reduced TTW has been associated with an increased risk of tibial tuberosity fracture, so MCLT is not recommended for clinical use.

Effect of intra-articular platelet-rich plasma or hyaluronic acid on limb function recovery in dogs with TPLO for cranial cruciate ligament rupture: a randomised controlled trial.

OBJECTIVES: This study aimed to investigate the recovery of limb function following a single intra-articular injection of platelet-rich plasma or hyaluronic acid in dogs with cranial cruciate ligament rupture treated with tibial plateau levelling osteotomy compared to dogs receiving no injection intraoperatively. MATERIALS AND METHODS: Sixty-two dogs with cranial cruciate ligament rupture, body weights of 20 to 40 kg, and no other orthopaedic conditions were enrolled in this prospective, randomised, double-blind, controlled study at the small animal clinic at LMU Munich. All dogs underwent tibial plateau levelling osteotomy. Based on random allocation, they received either a single intra-articular injection of platelet-rich plasma, hyaluronic acid or no injection intraoperatively. Gait analysis, clinical examinations, radiography of the stifle joint for osteoarthritis progression and two validated owner questionnaires were compared among groups at three timepoints postoperatively (6 weeks, 3 and 6 months). Limb function was primarily assessed by measuring the ground reaction forces. RESULTS: At all times postoperatively, no differences were observed among groups regarding clinical examinations, osteoarthritis score values, ground reaction forces or owner questionnaires. All dogs showed significant improvement in limb function clinically, in all ground reaction forces and in the validated questionnaires. Osteoarthritis progressed minimally during rechecks in all dogs regardless of the additional injection or not. CLINICAL SIGNIFICANCE: All dogs treated with tibial plateau levelling osteotomy for cranial cruciate ligament rupture showed improvements in limb function. No additive effect on faster recovery was demonstrated with the additional intra-articular injection of platelet-rich plasma or hyaluronic acid. Addition of platelet-rich plasma/hyaluronic acid injections during tibial plateau levelling osteotomy is unnecessary considering the lack of benefit observed up to 6 months postoperatively.

Evaluation of viscoelastic coagulation monitoring parameters and fibrinogen concentrations in healthy dogs undergoing stifle arthroscopy and tibial plateau leveling osteotomy.

OBJECTIVE: Evaluation of viscoelastic parameters along with Hct percentages, platelet numbers, and fibrinogen concentrations in healthy dogs undergoing elective stifle arthroscopy and tibial plateau leveling osteotomy (TPLO). These results determine if dogs are in a normal, hypocoagulable, or hypercoagulable state at 4 different time points. ANIMALS: Prospective study of 37 client-owned dogs enrolled between February 2, 2022, and November 10, 2022. METHODS: All dogs received a standardized anesthetic protocol. Patients enrolled in the study underwent stifle arthroscopy using a 3-portal technique with a TPLO performed by board-certified surgeons. Viscoelastic testing, Hct percentage, fibrinogen concentration, and platelet numbers were measured preoperatively, immediately postoperatively, 24 hours postoperatively, and 14 days postoperatively. RESULTS: Stifle arthroscopy and TPLO surgery was not associated with significant effects on viscoelastic coagulation monitoring and fibrinogen concentrations in healthy dogs when comparing the time points. CLINICAL RELEVANCE: Humans have a high risk of thrombotic events when undergoing elective orthopedic surgery and are often placed on prophylactic antithrombotic medication prior to surgery. Viscoelastic coagulation monitoring in dogs undergoing similar orthopedic procedures has been evaluated in veterinary medicine, but the effects on platelets and fibrinogen concentrations from similar orthopedic procedures and uniform anesthesia protocols have not been documented. Cranial cruciate ligament insufficiency is the most common orthopedic injury in dogs. Treatment requires elective surgical correction for the best results and improved long-term prognosis. The findings of this study suggest that similar preoperative prophylactic antithrombotic intervention is not needed for canine patients.

Short-term outcomes of cranial cruciate ligament rupture treated surgically with tibial plateau leveling osteotomy or non-surgically in small-breed dogs weighing less than10 kg.

Cranial cruciate ligament rupture (CCLR) is a common cause of stifle joint pain in dogs. This study assessed the short-term outcomes in the management of CCLR, with or without concurrent medial patellar luxation (MPL), in small-breed dogs, comparing surgical intervention using tibial plateau leveling osteotomy (TPLO) with non-surgical approaches. Dogs weighing less than 10 kg and suffering from CCLR were divided into two groups: surgical and non-surgical (nine stifles per group). Both groups followed the same rehabilitation protocol. Measurements were taken on days 0, 14, 28, 42, 56, 70, and 84. These measurements included the mean difference in orthopedic assessment score (diffOAS) and thigh muscle circumference (TMC) assessed by veterinarians, as well as the Canine Brief Pain Inventory score (CBPI) evaluated by the owners. Six stifles had concurrent MPL in the surgical group and five in the non-surgical group. No significant differences were observed in diffOAS (P=0.685), TMC (P=0.557), CBPI pain severity score (P=0.062), and CBPI pain interference score (P=0.29) between the two groups. However, both groups showed a significant decrease (P<0.05) in diffOAS and CBPI. The TMC remained relatively stable in the non-surgical group (P>0.05), but it significantly increased in the surgical group (P<0.05). Both groups demonstrated improved clinical outcomes in the short term, with no significant differences. However, cautious consideration should be given to a conservative treatment in small-breed dogs, particularly when considering the exclusive improvement observed in TMC within the TPLO group.

Biomechanical effects of cranial closing wedge osteotomy on joint stability in normal canine stifles: an ex vivo study.

BACKGROUND: Cranial closing wedge osteotomy (CCWO) is a functional stabilisation technique for cranial cruciate ligament (CrCL) ruptures. This biomechanical study aimed to evaluate the influence of CCWO on the stability of the stifle joint. Eighteen Beagle stifle joints were divided into two groups: control and CCWO. The stifle joints were analyzed using a six-degree-of-freedom robotic joint biomechanical testing system. The joints were subjected to 30 N in the craniocaudal (CrCd) drawer and proximal compression tests and 1 Nm in the internal-external (IE) rotation test. Each test was performed with an extension position, 135°, and 120° of joint angle. RESULTS: The stifle joints were tested while the CrCLs were intact and then transected. In the drawer test, the CCWO procedure, CrCL transection, and stifle joint flexion increased CrCd displacement. The CCWO procedure and CrCL transection showed an interaction effect. In the compression test, the CCWO procedure decreased and CrCL transection and stifle joint flexion increased displacement. In the IE rotation test, CCWO, CrCL transection, and stifle joint flexion increased the range of motion. CONCLUSIONS: CCWO was expected to provide stability against compressive force but does not contribute to stability in the drawer or rotational tests. In the CCWO-treated stifle joint, instability during the drawer test worsened with CrCL transection. In other words, performing the CCWO procedure when the CrCL function is present is desirable for stabilizing the stifle joint.

Delayed Life-Threatening Hemorrhage Caused by Cranial Tibial Artery Pseudoaneurysm in Two Dogs.

Two adult dogs were presented at 25 and 30 days following tibial external skeletal fixator placement (case 1) and tibial plateau leveling osteotomy (case 2), respectively. Clinical signs at presentation for each of them included acute onset lethargy, non-weight-bearing lameness, and hemorrhage at the surgical site with large hematoma formation. On admission, emergency whole blood transfusion was required in case 2 with a preoperative packed cell volume of 13%. Both dogs were diagnosed with pseudoaneurysm of the cranial tibial artery based on color Doppler ultrasonography. Additionally, computed tomography angiography was performed in one dog. Surgical treatment of the dogs included ligation of the cranial tibial artery supplying the pseudoaneurysm and curettage of hematoma. The surgery was completed without complications in case 1, but case 2 experienced inadvertent rupture of pseudoaneurysm with significant blood loss, which required another whole blood transfusion during the procedure. Both dogs had excellent functional recovery with no recurrence of clinical signs. We hypothesized that pseudoaneurysms were primarily caused by trauma secondary to placement of surgical implants or osteotomy. For orthopedic surgeons, it is important to recognize clinical signs of a potential tibial arterial pseudoaneurysm, as early surgical intervention may prevent loss of limb or life.

TTA-Rapid for treating the canine cruciate deficient stifle: Medium to long-term outcome and analysis of risk factors.

BACKGROUND: This study aimed to evaluate medium to long-term outcomes following treatment of lameness associated with cranial cruciate ligament insufficiency using the tibial tuberosity advancement (TTA)-Rapid technique and to investigate risk factors associated with outcome, including tibial plateau angle (TPA). METHODS: Patient records for cases treated over an 80-month period were examined retrospectively. An owner postal questionnaire using a clinical metrology instrument (Liverpool Osteoarthritis in Dogs) evaluated the outcome at least 6 months after surgery. RESULTS: A total of 149 procedures were carried out in 120 dogs. Questionnaires were received for 64 dogs (53.3%), with a median follow-up time of 37.5 months. Outcome was judged to be satisfactory, based on frequency of lameness, in 63 (98.4%), while satisfactory outcomes were achieved in 61 (95.3%) based on severity of lameness and in 50 (78.1%) based on mobility score. Statistical analysis showed that age, bodyweight, TPA, meniscal injury and concurrent patellar surgery did not influence outcome, but time to follow-up positively correlated with mobility score. LIMITATIONS: This study involved one surgeon in one centre with outcome data based on the completion of an owner questionnaire, although this used a validated clinical metrology instrument. CONCLUSION: TTA-Rapid offers a treatment option for cranial cruciate-deficient stifles with a good medium to long-term outcome, and no risk factors were identified to suggest any limitations to its use.

Novel crescentic, medial-closing, medially translating, centre-of-rotation-of-angulation-based, levelling osteotomy for lateral compartment stifle disease with partial cranial cruciate ligament tear in two dogs.

CASE HISTORY: Two mature, large breed dogs presented with chronic lameness and discomfort localised to the stifle. CLINICAL FINDINGS: No hindlimb deformities were present on physical examination or radiographic evaluation. No stifle instability was present. Arthroscopy revealed severe (grade 5/5 modified Outerbridge score) cartilage erosion in the lateral compartment (femorotibial), marked degeneration of the lateral meniscus and early cranial cruciate ligament disease in both patients. TREATMENT AND OUTCOME: Medial-closing, medially translating, centre-of-rotation-of-angulation-based, levelling osteotomy (mcmtCBLO) was performed in both patients. The procedure aims to shift the pelvic limb's mechanical axis medially to reduce pressure in the lateral compartment while also reducing craniocaudal shear forces by lowering the tibial plateau angle.Eight weeks after surgery one patient's lameness had resolved while the other had improved significantly. Second-look arthroscopy performed at this time revealed fibrocartilage formation in the lateral compartment without progression of cruciate disease in both cases. At long-term follow-up (approximately 3 and 5 years), favourable outcomes (no or minimal lameness, mild or moderate osteoarthritis) were identified on the long-term owner survey, lameness examination and radiographs. CLINICAL RELEVANCE: mcmtCBLO reduced or eliminated short- and long-term lameness in these two cases afflicted by concurrent lateral compartment and early cranial cruciate ligament disease.

Morphologic impact of four surgical techniques to correct excessive tibial plateau angle in dogs: A theoretical radiographic analysis.

OBJECTIVE: To determine morphologic differences between four tibial osteotomy techniques used to correct excessive tibial plateau angle (eTPA). STUDY DESIGN: Retrospective radiographic analysis. SAMPLE POPULATION: Sixteen dogs (27 tibias) with eTPA. METHODS: Virtual corrections of eTPA were performed on sagittal plane radiographs of canine tibia using four tibial osteotomy techniques and categorized into respective groups. Group A represented the center of rotation of angulation (CORA)-based leveling osteotomy (CBLO) and coplanar cranial closing wedge ostectomy (CCWO), Group B the tibial plateau leveling osteotomy (TPLO) and CCWO, Group C the modified CCWO (mCCWO), and Group D the proximal tibial neutral wedge osteotomy (PTNWO). Pre- and post-correction TPA, tibial length and mechanical cranial distal tibial angle (mCrDTA) were measured and compared. RESULTS: Mean TPA prior to correction was 42.67 ± 6.1°. Post-correction mean TPAs were 10.47 ± 2.1°, 6.77 ± 1.6°, 4.76 ± 1.5°, and 7.09 ± 1.3° for Groups A, B, C, and D, respectively. TPA correction accuracy in Groups A and D varied least from target TPAs. Tibial shortening was documented in Group B in contrast to other groups. The greatest mechanical axis shift was identified in Group A. CONCLUSION: Each technique achieved TPA < 14° despite having different effects on tibial morphology including alteration of tibial length, mechanical axis shift and variation in correctional accuracy. CLINICAL SIGNIFICANCE: Despite all methods being able to correct eTPA, the choice of technique will affect morphology in unique ways and should be considered prior to surgery to consider the implications in a given patient.

Diagnosis of medial meniscal lesions in the canine stifle using multidetector computed tomographic positive-contrast arthrography.

OBJECTIVE: To assess diagnostic value and clinical utility of multidetector computed tomographic positive contrast arthrography (CTA) for meniscal lesions in dogs. STUDY DESIGN: Prospective case series. STUDY POPULATION: Client-owned dogs (n = 55) with cranial cruciate ligament injuries. METHODS: Sedated dogs underwent CTA using a 16-slice scanner, and subsequently received mini-medial arthrotomy for meniscal assessment. Scans were anonymized, randomized, and reviewed twice for meniscal lesions by three independent observers with varying experience. Results were compared with surgical findings. Reproducibility and repeatability were assessed with kappa statistics, intraobserver changes in diagnosis by McNemar's test, and interobserver differences using Cochran's Q test. Test performance was calculated using sensitivity, specificity, proportion correctly identified, and positive and negative predictive values and likelihood ratios. RESULTS: Analysis was based on 52 scans from 44 dogs. Sensitivity for identifying meniscal lesions was 0.62-1.00 and specificity was 0.70-0.96. Intraobserver agreement was 0.50-0.78, and interobserver agreement was 0.47-0.83. There was a significant change between readings one and two for the least experienced observers (p < .05). The sum of sensitivity and specificity exceeded 1.5 for both readings and all observers. CONCLUSION: Diagnostic performance was suitable for identifying meniscal lesions. An effect of experience and learning was seen in this study.

Objective comparison of a sit to stand test to the walk test for the identification of unilateral lameness caused by cranial cruciate ligament disease in dogs.

OBJECTIVE: The purpose of this study was to evaluate a sit to stand test with the walk test for the identification of unilateral cranial cruciate ligament rupture in dogs. MATERIALS AND METHODS: Peak vertical force and vertical impulse were measured on a pressure-sensitive walkway, during a sit to stand test and walk test, and in 10 dogs with unilateral cranial cruciate ligament rupture and 18 non-lame dogs. Data collected were used to calculate symmetry indices (SI) of ipsilateral and contralateral hindlimbs (HL), diagonal limb pairs (DLP) and ipsilateral limb pairs (ILP). RESULTS: The symmetry indices of peak vertical force of HL during the walk test and sit to stand test were 100% and 90% sensitive for discriminating lame and non-lame dogs respectively. The symmetry indices of vertical impulse of HLs during the walk test and sit to stand test were 100% and 50% sensitive for discriminating lame and non-lame dogs respectively. Analysis of ipsilateral and diagonal limb pairs did not improve the discrimination in either test. The time taken to collect data from the sit to stand test data was shorter than for the walk test. CLINICAL SIGNIFICANCE: Whilst the sit to stand test required a shorter time for collection of data than the walk test, it did not accurately identify all dogs with lameness associated with CCLR, and thus has relatively limited clinical utility in its tested form.

Photobiomodulation therapy in dogs undergoing TPLO after cranial cruciate ligament rupture shows promise but no statistically significant difference in a randomized trial.

OBJECTIVE: Effect of photobiomodulation therapy (PBMT) in patients with CCLR after TPLO surgery by measuring C-reactive protein (CRP), percentage weight bearing, lameness using a short form of a composite measure pain scale, evaluated by the clinician and owners, and surgical site infection. SAMPLE: 54 client-owned dogs with CCLR undergoing unilateral TPLO surgery were enrolled in this study between April 5, 2021, through April 10, 2022. METHODS: The study population was randomly assigned to either a treatment group receiving PMBT (24 dogs) or a control group (30 dogs). PMBT was performed on the treatment group immediately after induction, and 6 hours, 24 hours, 48 hours, and 8 weeks postoperatively. The control group received sham PMBT (device turned off) at the same time. Evaluation of CRP, CMPS-SF, evidence of SSI, and %WB were evaluated for all dogs 24 hours preoperatively, and then 24 hours, 48 hours, and 8 weeks postoperatively. Owners completed CMPS-SF and subjective evaluations weekly for 8 weeks postoperatively. RESULTS: No statistically significant differences were found between treatment groups when evaluating CRP, %WB, and CMPS-SF by the clinician and weekly evaluation of the CMPS-SF by owners. Although no statistically significant differences were found in patients developing surgical site infections between treatment groups, SSI was only observed in patients in the control group (5/30, 16.6%). Most were minor/superficial infections (4/30 13.3%), and a single dog (1/30, 3.3%) had a major/deep surgical site infection. CLINICAL RELEVANCE: Although with promising but not statistically significant differences between groups, surgical site infections may be reduced after PBMT application.

Determining predictive metabolomic biomarkers of meniscal injury in dogs with cranial cruciate ligament rupture.

OBJECTIVES: This study used hydrogen nuclear magnetic resonance spectroscopy for the first time to examine differences in the metabolomic profile of stifle joint synovial fluid from dogs with cranial cruciate ligament rupture with and without meniscal injuries, in order to identify biomarkers of meniscal injury. Identifying a biomarker of meniscal injury could then ultimately be used to design a minimally invasive diagnostic test for meniscal injuries in dogs. MATERIALS AND METHODS: Stifle joint synovial fluid was collected from dogs undergoing stifle joint surgery or arthrocentesis for lameness investigations. We used multi-variate statistical analysis using principal component analysis and univariate statistical analysis using one-way analysis of variance and analysis of co-variance to identify differences in the metabolomic profile between dogs with cranial cruciate ligament rupture and meniscal injury, cranial cruciate ligament rupture without meniscal injury, and neither cranial cruciate ligament rupture nor meniscal injury, taking into consideration clinical variables. RESULTS: A total of 154 samples of canine synovial fluid were included in the study. Sixty-four metabolites were annotated to the hydrogen nuclear magnetic resonance spectroscopy spectra. Six spectral regions were found to be significantly altered (false discovery rate adjusted P-value <0.05) between groups with cranial cruciate ligament rupture with and without meniscal injury, including three attributed to nuclear magnetic resonance mobile lipids [mobile lipid -CH3 (P=0.016), mobile lipid -n(CH3 )3 (P=0.017), mobile unsaturated lipid (P=0.031)]. CLINICAL SIGNIFICANCE: We identified an increase in nuclear magnetic resonance mobile lipids in the synovial fluid of dogs with meniscal injury which are of interest as potential biomarkers of meniscal injury.

Influence of antiseptic lavage during tibial plateau leveling osteotomies on surgical site infection in 1422 dogs.

OBJECTIVE: To determine the influence of preclosure antiseptic versus saline lavage on surgical site infections (SSI) in dogs following tibial plateau leveling osteotomy (TPLO). STUDY DESIGN: A multicenter retrospective study. SAMPLE POPULATION: Dogs treated with TPLO (n = 1422) between December 2019 and October 2021. METHODS: The medical records of dogs treated with TPLO were reviewed for preclosure antiseptic lavage or saline irrigation. Additional collected data included signalment, unilateral or bilateral TPLO, postoperative administration of antimicrobial medications, antibiotic agent, surgeon, and development of SSI within 90 postoperative days. Eleven factors were analyzed for association with SSI using univariate and multivariate analysis. RESULTS: Data were collected from the records of 519 dogs treated with antiseptic lavage and 903 dogs treated with saline lavage during TPLO. Surgical site infections were diagnosed more frequently in dogs that received preclosure antiseptic lavage (77/519, 14.84%) than those with saline irrigation (80/903, 8.86%) (p = .001). Single session bilateral TPLO increased the odds of SSI by 2.5x (p = .004). The odds of SSI increased by 11% (p = .001) for every 5 kg increase in bodyweight. Postoperative administration of antimicrobials decreased the risk of SSI (p = .008). CONCLUSION: The preclosure antiseptic lavage tested here did not decrease the incidence of SSI after TPLO. CLINICAL SIGNIFICANCE: The results of this study do not provide evidence to support preclosure antiseptic lavage during TPLOs.

Predicting tibial plateau angles following four different types of cranial closing wedge ostectomy.

OBJECTIVE: To investigate how tibial long axis (TLA) shift affects the postoperative tibial plateau angle (TPA) in four cranial closing wedge ostectomy (CCWO) techniques. STUDY DESIGN: In silico study. SAMPLE POPULATION: A total of 15 client-owned dogs. METHODS: Computed tomography (CT) scans of 15 client-owned dogs were reviewed using an open-source 3D computer graphics editor. Each computer-generated 3D tibia model underwent a CCWO, with cranial cortex alignment, in 10° increments up to 70° using each of the four previously described techniques. The TLA shift, TPA and mechanical tibial length (mTL) were calculated, using trigonometry, for each model. Equations for predicting final TPA were generated with linear regression. RESULTS: A total of 433 3D computer generated tibial models were analyzed. With each technique, the TPA varied in a linear fashion within the studied range of wedge angles. The TLA shift and tibial shortening magnitude varied between the four different CCWO techniques, with maximum mTL reduction of ranging from 7.5% to 40.9%. All predicted TPAs using the generated equations were within the target range of 4-6°. CONCLUSION: A linear relationship between ostectomy wedge angle and TPA correction was observed in this study, which allowed for generation of accurate corrective equations. CLINICAL SIGNIFICANCE: These results allow extrapolation of the wedge angle required to reach a postoperative TPA of 5°, by considering the TLA shift. The use of the generated corrective equations may thus increase CCWO planning precision.

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

OBJECTIVE: (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. STUDY DESIGN: Cross-sectional retrospective radiographic in silico study. SAMPLE POPULATION: A total of 100 stifle radiographs; 90 dogs (small ≤25 kg = 84; large >25 kg = 16). METHODS: 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. RESULTS: 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. CONCLUSIONS: Oxley's modified CCWO did not result in TPA of 5° in most cases. Ostectomy distalization exacerbated under-correction. CLINICAL IMPACT: Current guidelines should be modified to achieve 5° TPA postoperatively.

Complications and Long-Term Outcomes after Combined Tibial Plateau Leveling Osteotomy and Tibial Tuberosity Transposition for Treatment of Concurrent Cranial Cruciate Ligament Rupture and Grade III or IV Medial Patellar Luxation.

OBJECTIVES: This study aims to report complications and long-term outcomes of combined tibial plateau leveling osteotomy and tibial tuberosity transposition (TPLO-TTT) for treatment of concurrent cranial cruciate ligament rupture and medial patellar luxation (MPL). STUDY DESIGN: This is a retrospective study. Dogs that underwent TPLO-TTT for treatment of combined cranial cruciate ligament rupture and grade III or IV MPL were included. Signalment, fixation method, and complications were recorded. Long-term outcome assessment (minimum 1 year postoperatively) was performed through clinical and radiographic reexamination at the authors' institution. RESULTS: Twenty-four stifles (22 dogs) were included. Twenty-one stifles had a grade III MPL, and 3 stifles had grade IV MPL. Four major complications consisting of surgical site infection (n = 3) and recurrent grade II MPL (n = 1) were observed. Dogs with surgical site infections were successfully treated with implant removal and oral antibiotics. No additional surgery was performed for the patient with recurrent MPL as no signs of lameness were observed. Minor complications occurred in five cases. At long-term evaluation (median: 27 months; range: 12-67 months), 21/22 dogs were clinically sound and 23/24 stifles had a complete resolution of MPL. CONCLUSION: TPLO-TTT can be considered as an effective surgical option to treat patients with concurrent cranial cruciate ligament rupture and MPL with a relatively low major complication rate. Owners should be warned of the potential need for implant removal.

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

OBJECTIVE: 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. STUDY DESIGN: 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. RESULTS: 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. CLINICAL RELEVANCE: 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.

Cranial closing wedge ostectomies for management of canine cranial cruciate ligament insufficiency: Comparison and geometric modelling of errors.

Variants of the cranial closing wedge ostectomy (CCWO) may be used to manage cranial cruciate ligament deficient stifles by reduction of the tibial plateau angle (TPA). Concerns have been raised about predictability of achieving target TPA, limb shortening, axis shift, and distalization of the tibial tuberosity. Landmarks derived from tibial radiographs (n = 50) by 5 observers, along with outlines of the cranial and caudal proximal tibial cortices, were used to simulate six CCWO variants. Tested variants were Slocum-type (n = 2), modified (n = 2), isosceles, and anatomical-mechanical axis (AMA)-based CCWO. Observer specific landmarks were used to model pre- and postoperative errors in TPA measurement. Mean landmarks were used to compare key outcome variables between the variants, as well as modelling errors in positioning the wedge apex. Variants differed markedly in TPA, axis shift, mechanical axis length changes, and tibial tuberosity distalization, with more proximally positioned wedges performing better than distally positioned wedges. Errors in TPA identification appeared partially self-correcting due to altered axis shifts. Craniocaudal shifts in wedge apex position had the most severe effects on outcome variables, especially in shorter tibiae with greater initial TPA values. Recent CCWO variants are likely to achieve a satisfactory postoperative TPA with limited axis shift. The AMA-based CCWO technique appears to influence MA length and tibial tuberosity position the least, and apart from the effect on TPA where no advantage could be discerned, it appeared more robust in the face of wedge apex positioning errors than the other techniques.