Biomechanical evaluation of a fixation technique with a modified hemicerclage for tibial tuberosity transposition: an ex vivo cadaveric study

Objectives(1) To determine stiffness, load at failure, and mode of failure of a novel fixation method with a tension modified-hemicerclage (MH) for tibial tuberosity transposition, and (2) to compare the biomechanical properties of this novel fixation technique to 2 pins (2Pins) and 2 pins and tension band wire fixation (2Pins + TBW).Study designThirty cadaveric stifles from dogs between 5.2 and 13.1 kg were assigned to 3 treatment groups: Group 1: fixation technique with MH; Group 2: 2Pins; Group 3: 2Pins + TBW. Biomechanical testing was performed with the tibia positioned at an angle of 135° relative to vertical position. Tensile force was applied to the patellar ligament until catastrophic failure was observed. The mode of failure, the load at failure, and the stiffness were compared among treatment groups.ResultsThe mean stiffness of the novel fixation (38.1 N/mm ± 7.1) and the 2Pins + TBW (40.2 N/mm ± 9.3) were greater than the 2Pins (26.7 N/mm ± 6.7). There was no significant difference between the novel fixation technique and 2Pins + TBW in stiffness and maximum load to failure. The 2Pins (284.3 N ± 70.5) failed at a significantly lower load than the tension modified-hemicerclage (555.7 N ± 225.9 N) and 2Pins + TBW (715.3 N ± 339.8 N).ConclusionA fixation technique using a modified hemicerclage had the same strength and stiffness as the 2Pins + TBW and was stronger and stiffer than the 2 Pins technique in a cadaveric model

Surgical management of choledocholithiasis in a dog

A 7 year-old female spayed Presa Canario was presented to the Cornell University Hospital for Animals (CUHA) on 6/22/2011 after a 10-day history of vomiting, inappetence, and lethargy. The referring veterinarian had documented rising liver enzymes and suspected liver failure of unknown toxic cause. Initial diagnostics at CUHA confirmed increased hepatobiliary enzymes (ALT, AST, ALP, GGT), hyperbilirubinemia, hypercholesterolemia, hypoalbuminemia, and low BUN. Abdominal ultrasound revealed a gallbladder in the high-normal volume range at 2ml/kg and liver aspirates showed vacuolar degeneration of hepatocytes consistent with cholestasis. No evidence of bile duct obstruction was discovered and the dog was managed medically for non-specific infectious and toxic causes of acute liver disease. Liver values were monitored daily and continued to worsen while the dog also became depressed and anorexic and continued to vomit. The dog developed icterus and acholic feces. Repeat abdominal ultrasound was performed five days after admission and revealed an increased gallbladder volume to 3ml/kg and significant dilation of extra and intra-hepatic bile ducts. This information combined with worsening clinical signs and blood chemistry values justified exploratory laparotomy. The cause of bile duct obstruction was determined to be a cholelith within the ductus choledochus and choledocholithotomy and cholecystectomy were performed. The dog improved clinically and hematologically and was discharged from the hospital four days after surgery. The patient has been monitored by the referring veterinarian and continues to do well four months after surgery with the only abnormality being a mildly increased ALT

Patellofemoral kinematics in dogs with cranial cruciate ligament insufficiency: an in-vivo fluoroscopic analysis during walking

BACKGROUND: Complete rupture of the cranial cruciate ligament (CrCL) in dogs causes profound disturbance to stifle joint biomechanics. The objective of this study was to characterize the effects of cranial cruciate ligament (CrCL) insufficiency on patellofemoral (PF) kinematics in dogs during walking. Ten client-owned dogs (20-40 kg) with natural unilateral complete CrCL rupture were included. Dogs underwent computed tomographic scans to create digital bone-models of the patella and femur. Lateral projection fluoroscopy of the stifles was performed during treadmill walking. Sagittal plane PF kinematics were calculated throughout the gait cycle by overlaying digital bone models on fluoroscopic images using a previously described 2D-3D registration technique. For acquisition of kinematics in the contralateral (control) stifle, fluoroscopy was repeated 6-months after stabilizing surgery of the affected side. Results were compared between the pre-operative CrCL-deficient and 6-month post-operative control stifles. RESULTS: Craniocaudal PF translation was similar between CrCL-deficient and control stifles throughout the gait cycle. The patella was more distal and positioned in greater flexion throughout the gait cycle in CrCL-deficient stifles when compared to the control stifle at equivalent time points. There was no significant difference in PF poses between CrCL-deficient and control stifles at equivalent femorotibial flexion angles; however, common femorotibial flexion angles were only found over a small range during the swing phase of gait. CONCLUSIONS: CrCL insufficiency altered PF kinematics during walking, where the changes were predominately attributable to the femorotibial joint being held in more flexion. Abnormal PF kinematics may play a role in the development of osteoarthritis that is commonly observed in the PF joint CrCL-deficient stifles

The effect of tibial plateau leveling osteotomy on patellofemoral kinematics in dogs: an in vivo study

OBJECTIVE: To quantitatively evaluate patellofemoral (PF) kinematics during walking in dogs with cranial cruciate ligament (CrCL) deficiency treated by tibial plateau leveling osteotomy (TPLO). STUDY DESIGN: Longitudinal observational study. ANIMALS: Dogs with unilateral CrCL deficiency treated by TPLO (n = 10). METHODS: Horizontal beam fluoroscopic images of the stifles during treadmill walking were acquired 6 months after TPLO. Computed tomography was performed, and digitized bone models of both femurs and patellae were created. These digital models were superimposed over the fluoroscopic images with shape-matching software, and sagittal plane PF kinematics for TPLO-treated and normal contralateral stifles were calculated. Patellofemoral kinematics were described according to phase of gait cycle as well as relative to femorotibial flexion angle. RESULTS: In TPLO-treated stifles, there was an approximately 1-mm increase in cranial displacement of the patella (P < .05) compared with the normal stifle at equivalent femorotibial flexion angles between 120° and 140° and predominately during the stance phase. Proximal-distal translation and patellar flexion angle were mostly unaffected by TPLO when they were assessed according to either equivalent phase of gait cycle or femorotibial flexion angles. CONCLUSION: In vivo PF kinematics in TPLO-treated stifles were subtly different from normal, characterized by slight cranial shifting of the patella relative to the trochlear groove. CLINICAL SIGNIFICANCE: The clinical significance of these results remains unknown. These results may provide further understanding into extensor mechanism abnormalities associated with TPLO

Patellofemoral kinematics in dogs with cranial cruciate ligament insufficiency: an in-vivo fluoroscopic analysis during walking

Abstract Background Complete rupture of the cranial cruciate ligament (CrCL) in dogs causes profound disturbance to stifle joint biomechanics. The objective of this study was to characterize the effects of cranial cruciate ligament (CrCL) insufficiency on patellofemoral (PF) kinematics in dogs during walking. Ten client-owned dogs (20-40 kg) with natural unilateral complete CrCL rupture were included. Dogs underwent computed tomographic scans to create digital bone-models of the patella and femur. Lateral projection fluoroscopy of the stifles was performed during treadmill walking. Sagittal plane PF kinematics were calculated throughout the gait cycle by overlaying digital bone models on fluoroscopic images using a previously described 2D-3D registration technique. For acquisition of kinematics in the contralateral (control) stifle, fluoroscopy was repeated 6-months after stabilizing surgery of the affected side. Results were compared between the pre-operative CrCL-deficient and 6-month post-operative control stifles. Results Craniocaudal PF translation was similar between CrCL-deficient and control stifles throughout the gait cycle. The patella was more distal and positioned in greater flexion throughout the gait cycle in CrCL-deficient stifles when compared to the control stifle at equivalent time points. There was no significant difference in PF poses between CrCL-deficient and control stifles at equivalent femorotibial flexion angles; however, common femorotibial flexion angles were only found over a small range during the swing phase of gait. Conclusions CrCL insufficiency altered PF kinematics during walking, where the changes were predominately attributable to the femorotibial joint being held in more flexion. Abnormal PF kinematics may play a role in the development of osteoarthritis that is commonly observed in the PF joint CrCL-deficient stifles

Effect of storage duration on carprofen concentration measurements in dog plasma

Abstract Background Storage of samples may be necessary prior to testing drug levels in certain study designs; however, the effect of storage duration on measured drug levels is not known for all drugs. Objectives The objective of this study was to evaluate the stability of carprofen in canine plasma when stored at −80°C for 6 months. Methods Six healthy dogs were enrolled (1–10 years old, 17–35 kg) and received compounded carprofen at 2.2 mg/kg orally every 12 h for 2 days. On the third day, blood was collected immediately before the morning dose (trough), then 1 and 6 h after the dose (sampling timepoint). Whole blood was immediately centrifuged, and plasma was stored at −80°C. Plasma carprofen concentration was measured at day 2, week 2 and then monthly for 6 months using reversed‐phase high‐performance liquid chromatography. The measured carprofen concentrations were analysed statistically using a linear mixed effects model. Results There was no effect of storage time over 6 months (p = 0.891) on measured carprofen levels. Although there was an effect of sampling timepoint (0, 1 and 6 h) (p < 0.001), the interaction between storage timepoint and sampling timepoint was not statistically significant (p = 1). Conclusions Carprofen‐laden canine plasma samples can be stored for up to 6 months before analysis with no degradation in carprofen concentrations expected

Femorotibial kinematics in dogs with cranial cruciate ligament insufficiency: a three-dimensional in-vivo fluoroscopic analysis during walking

Abstract Background Cranial cruciate ligament (CrCL) insufficiency is a degenerative condition that is a common cause of pelvic limb lameness and osteoarthritis in dogs. Surgical therapies developed to treat dogs with naturally occurring CrCL insufficiency aim to address the resultant instability, but the in-vivo alterations in stifle kinematics associated with CrCL insufficiency have not been accurately defined. The objective of this study was to quantify the 3-dimensional femorotibial joint kinematics of dogs with naturally occurring cranial cruciate ligament (CrCL) insufficiency during ambulation. Eighteen client-owned dogs (20–40 kg) with natural unilateral complete CrCL rupture were included. Computed tomographic scans were used to create digital 3-dimensional models of the femur and tibia bilaterally for each dog. Lateral fluoroscopic images were obtained during treadmill walking and 3 complete gait cycles were analyzed. Stifle flexion/extension angle, craniocaudal translation, and internal/external rotation were calculated throughout the gait cycle using a previously described 3D-to-2D image registration process. Results were compared between the pre-operative CrCL-deficient and 6-month post-operative contralateral stifles (control). Results CrCL-deficient stifles were maintained in greater flexion throughout the gait cycle. Cranial tibial subluxation was evident in CrCL-deficient stifles at all time points throughout the gait cycle [9.7 mm at mid-stance (P < 0.0001); 2.1 mm at mid-swing (P < 0.0017)], and the magnitude of cranial tibial subluxation was greater at mid-stance phase than at mid-swing phase (P < 0.0001). Greater internal tibial rotation was present in CrCL-deficient stifles during stance phase (P < 0.0022) but no difference in axial rotation was evident during swing phase. Conclusions Naturally occurring CrCL rupture causes profound craniocaudal translational and axial rotational instability, which is most pronounced during the stance phase of gait. Surgical stabilization techniques should aim to resolve both craniocaudal subluxation and axial rotational instability

Femorotibial kinematics in dogs with cranial cruciate ligament insufficiency: a three-dimensional in-vivo fluoroscopic analysis during walking

BACKGROUND: Cranial cruciate ligament (CrCL) insufficiency is a degenerative condition that is a common cause of pelvic limb lameness and osteoarthritis in dogs. Surgical therapies developed to treat dogs with naturally occurring CrCL insufficiency aim to address the resultant instability, but the in-vivo alterations in stifle kinematics associated with CrCL insufficiency have not been accurately defined. The objective of this study was to quantify the 3-dimensional femorotibial joint kinematics of dogs with naturally occurring cranial cruciate ligament (CrCL) insufficiency during ambulation. Eighteen client-owned dogs (20-40 kg) with natural unilateral complete CrCL rupture were included. Computed tomographic scans were used to create digital 3-dimensional models of the femur and tibia bilaterally for each dog. Lateral fluoroscopic images were obtained during treadmill walking and 3 complete gait cycles were analyzed. Stifle flexion/extension angle, craniocaudal translation, and internal/external rotation were calculated throughout the gait cycle using a previously described 3D-to-2D image registration process. Results were compared between the pre-operative CrCL-deficient and 6-month post-operative contralateral stifles (control). RESULTS: CrCL-deficient stifles were maintained in greater flexion throughout the gait cycle. Cranial tibial subluxation was evident in CrCL-deficient stifles at all time points throughout the gait cycle [9.7 mm at mid-stance (P < 0.0001); 2.1 mm at mid-swing (P < 0.0017)], and the magnitude of cranial tibial subluxation was greater at mid-stance phase than at mid-swing phase (P < 0.0001). Greater internal tibial rotation was present in CrCL-deficient stifles during stance phase (P < 0.0022) but no difference in axial rotation was evident during swing phase. CONCLUSIONS: Naturally occurring CrCL rupture causes profound craniocaudal translational and axial rotational instability, which is most pronounced during the stance phase of gait. Surgical stabilization techniques should aim to resolve both craniocaudal subluxation and axial rotational instability

Femorotibial kinematics in dogs treated with tibial plateau leveling osteotomy for cranial cruciate ligament insufficiency: an in vivo fluoroscopic analysis during walking

OBJECTIVE: To determine the ability of tibial plateau leveling osteotomy (TPLO) to address abnormal femorotibial kinematics caused by cranial cruciate ligament (CCL) rupture during walking in dogs. STUDY DESIGN: Prospective, clinical. ANIMALS: Sixteen dogs (20-40 kg) with unilateral complete CCL rupture. METHODS: Lateral view fluoroscopy was performed during treadmill walking preoperatively and 6 months after TPLO. Digital three-dimensional (3D) models of the femora and tibiae were created from computed tomographic (CT) images. Gait cycles were analyzed by using a 3D-to-2D image registration process. Craniocaudal translation, internal/external rotation, and flexion/extension of the femorotibial joint were compared between preoperative and 6-month postoperative time points for the affected stifle and 6-month postoperative unaffected contralateral (control) stifles. RESULTS: In the overall population, CCL rupture resulted in 10 ± 2.2 mm (mean ± SD) cranial tibial translation at midstance phase, which was converted to 2.1 ± 4.3 mm caudal tibial translation after TPLO. However, five of 16 TPLO-treated stifles had 4.1 ± 0.3 mm of cranial tibial subluxation during mid-to-late stance phase, whereas 10 of 16 TPLO-treated stifles had 4.3 ± 0.4 mm of caudal tibial subluxation throughout the gait cycle. Overall, postoperative axial rotational and flexion/extension patterns were not different from control, but stifles with caudal tibial subluxation had more external tibial rotation during mid-to-late stance phase compared with stifles with cranial tibial subluxation. CONCLUSION: TPLO mitigated abnormal femorotibial kinematics but did not restore kinematics to control values in 15 of 16 dogs during walking. CLINICAL SIGNIFICANCE: Tibial plateau leveling osteotomy reduces cranial tibial subluxation during walking, but persistent instability is common