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Objective: To describe the technique of combined center of rotation of angulation (CORA)-based leveling osteotomy (CBLO) with tibial tuberosity transposition (TTT) and to compare the load to failure between CBLO combined with TTT and CBLO or TTT alone., Study Design: Ex vivo study., Sample Population: Twelve pairs of cadaveric pelvic limbs., Methods: Six pairs of cadaveric tibia were tested in each group (CBLO-TTT versus CBLO) and (CBLO-TTT versus TTT) with each limb randomly assigned to a treatment group. Construct stability was determined by applying a tensile force to each patellar tendon until failure occurred. Load at failure and mode of failure were recorded for each specimen., Results: No difference in mean load to failure was identified between CBLO-TTT (897 N) and CBLO alone (943 N) (P = .81). There was also no difference in the mean load to failure between the CBLO-TTT (928 N) and TTT alone (1046 N) (P = .12)., Conclusion: Performing a TTT in combination with a CBLO does not weaken the construct failure to load when compared with each procedure performed alone., Clinical Significance: A combined CBLO and TTT could be considered a viable option for concurrent management of a cranial cruciate ligament deficient stifle and medial patella luxation., (© 2022 American College of Veterinary Surgeons.)

Objective: To describe short-term outcomes of center of rotation of angulation (CORA)-based leveling osteotomy (CBLO) in skeletally immature dogs with cranial cruciate ligament (CrCL) injury., Study Design: Retrospective case series., Animals: Fifteen skeletally immature dogs (16 stifles)., Methods: Medical records of dogs with CrCL injury and radiographically documented open proximal tibial physis and tibial tuberosity apophysis managed with CBLO were reviewed. Clinical assessment, radiographic assessment, and complications were reviewed., Results: Fifteen dogs (16 stifles) with radiographically documented open proximal tibial physis and tibial tuberosity apophysis and CrCL injury underwent a CBLO. Mean tibial plateau angle (TPA) was 26° preoperatively, 9° postoperatively, and 9° at final recheck. One dog developed 10° recurvatum of the proximal tibia secondary to inadvertent over rotation of the tibial plateau (TPA 3°) to protect primary repair of an insertional CrCL avulsion. Correction of the recurvatum was declined as the dog had full limb function. Two dogs developed a valgus deformity secondary to a plate screw engaging the distolateral aspect of the proximal tibial physis. Owners of these dogs reported normal function but requested surgical revision to prevent long-term problems secondary to abnormal weight bearing. Both dogs regained full function following recovery from revision surgery. At a mean time of 23 months following surgery, all dogs continued to have full function as per phone conversation with owners., Conclusion: With proper preoperative planning, CBLO is an option for skeletally immature dogs with CrCL injury., (© 2022 American College of Veterinary Surgeons.)

Objective: To determine the diagnostic significance of the meniscal flounce sign in association with meniscal tears., Study Design: Prospective cohort study., Sample Population: One hundred and thirty stifles in 120 client-owned dogs that underwent stifle arthroscopy., Methods: Identification of a positive or negative meniscal flounce sign was recorded with the presence or absence of meniscal pathology. Sensitivity, specificity, positive and negative predictive values, and diagnostic accuracy were calculated., Results: Eighty-nine stifles (68.5%) were noted to have a positive meniscal flounce sign. Of these stifles, four were noted to have a meniscal tear, and they were all radial tears. A total of 41 stifles (31.5%) had a negative meniscal flounce. Of these stifles, 38 had a meniscal tear. The sensitivity, specificity, positive and negative predictive values, and diagnostic accuracy of the meniscal flounce sign for indicating an intact or torn meniscus were 96.6%, 90.5%, 95.5%, 92.7%, and 94.6%, respectively., Conclusion: A positive meniscal flounce sign was associated with a normal meniscus and the absence of the flounce sign was associated with a meniscal tear., Clinical Significance: Identification of the meniscal flounce sign during stifle arthroscopy is a strong indicator of a normal medial meniscus. The absence of the sign strongly indicates the presence of meniscal pathology., (© 2021 American College of Veterinary Surgeons.)

Objective: To describe outcomes of dogs with excessive tibial plateau angle (eTPA) and cranial cruciate ligament (CrCL) disease treated with center of rotation of angulation-based leveling osteotomy (CBLO) and cranial closing wedge ostectomy (CCWO)., Study Design: Retrospective study., Animals: Twenty-one dogs., Methods: Medical records of dogs with CrCL disease and eTPA (>34°) treated with CBLO/CCWO were reviewed. Signalment, body weight, intra-articular structure appearance, TPA (preoperatively, postoperatively, and at osteotomy healing), postoperative function, and complications were recorded., Results: Twenty-one dogs (28 stifles) with CrCL disease/eTPA underwent CBLO/CCWO. Twenty stifles had complete CrCL tears and eight tears were partial. Mean age and weight of dogs were 4 years (range, 1-9) and 27 kg (range, 4-65), respectively. Medial menisci were normal in 20 stifles, torn in 5, and degenerative in 3. All lateral menisci were normal. The caudal cruciate ligament was normal in 26 stifles and partially torn in 2. Mean TPA was 43° preoperatively, 10° postoperatively, and 10° at final recheck. Grade 4 healing occurred in all osteotomies by 8 weeks postoperatively. Complications included one pin migration, breakage of two proximal screws (1 case), one late-onset caudolateral band CrCL tear, two late-onset meniscal tears, and one surgical site infection. Eighteen dogs returned to full function, and three dogs achieved acceptable function, at a mean of 27 months., Conclusion: Center of rotation of angulation-based leveling osteotomy/CCWO resulted in grade 4 osteotomy healing by 8 weeks, minimal complications, and acceptable to full return to function., Clinical Significance: Center of rotation of angulation-based leveling osteotomy/CCWO should be considered to treat canine CrCL disease/eTPA., (© 2020 The American College of Veterinary Surgeons.)

Objective: To determine the mechanical pull-out properties of a 2.5-mm bone anchor implanted in ex vivo femurs of toy breed dogs and to determine whether there is a difference between knotted and knotless configurations., Study Design: Experimental study., Sample Population: Eight paired harvested femurs., Methods: Femurs were assigned to knotted or knotless configuration. Equal numbers of right and left femurs were tested. The caudolateral femoral condyle at the distal pole of the lateral fabella (F2 site) was drilled. The assigned configuration with braided suture combined with the bone anchor was implanted into the F2 site. Each configuration was positioned into a mechanical testing machine to measure yield load, load at 3-mm displacement, ultimate load, stiffness, and mode of failure at the beginning of the canine standing phase angle (150°)., Results: Mean ultimate load was 100.14 and 88.69 N (P = .798), mean yield load was 59.72 and 55.85 N (P = .708), load at 3-mm displacement was 46.72 and 43.33 N (P = .656), and stiffness was calculated to be 43.06 and 47.09 N/mm (P = .548) for knotted and knotless configurations, respectively. Mode of failure occurred primarily by anchor pull-out., Conclusion: The bone anchor withstood deformation at the estimated forces applied on the native cranial cruciate ligament (CCL) of toy breed dogs in both configurations., Clinical Significance: This bone anchor may constitute a useful alternative for stabilization of the CCL deficient stifle in toy breed dogs. However, before it can be recommended for widespread use in dogs, closely monitored clinical trials must be conducted to assess outcome and complications associated with this implant., (© 2020 The American College of Veterinary Surgeons.)

Case Description: 3 adult Basset Hounds were referred for evaluation of chronic, unilateral, pelvic limb lameness with no history of trauma., Clinical Findings: On examination, all dogs had mild lameness of the affected limb; signs of pain were evident during manipulation of the stifle joint in the affected limb, along with effusion of that joint. No stifle joint instability was palpable. Radiographs were available for review for 2 of the 3 dogs. Effusion was confirmed radiographically, but severity of degenerative joint disease varied. Central intercondylar notch width ratios for the 2 dogs were 0.16 and 0.17, and tibial plateau angles were -10° and 15°; relative tibial tuberosity width was 1.1 for both dogs. Exploratory arthroscopy revealed moderate degeneration of the caudal cruciate ligament in all 3 dogs; the cranial cruciate ligaments were grossly normal., Treatment and Outcome: Corrective osteotomy to increase the tibial plateau angle was performed in 1 dog, and the lameness resolved by 2 months after surgery. The 2 other dogs were managed without additional surgery. One dog was persistently lame. The other dog reportedly had normal limb function 2.5 years after undergoing exploratory arthroscopy., Clinical Relevance: Morphological characteristics of the tibia in Basset Hounds may predispose to abnormal stresses on the caudal cruciate ligament. Isolated degeneration of the caudal cruciate ligament should be considered as a differential diagnosis for Basset Hounds with lameness originating from the stifle joint. Without direct inspection of the joint, caudal cruciate ligament disease could be confused for cranial cruciate ligament injury.

Objective: To describe articular cartilage (AC) lesions associated with complete lateral meniscal tears in dogs., Study Design: Observational series., Animals: Seventeen dogs with arthroscopic evidence of a complete lateral meniscal tear and associated AC lesions., Methods: Medical records of dogs with arthroscopic evidence of complete lateral meniscal tear and associated AC lesions between March 2006 and December 2017 were examined for arthroscopic findings., Results: The cranial cruciate ligament (CrCL) was intact in 11 of 17 dogs, partially ruptured but competent in 4 of 17 dogs, and completely ruptured in 2 of 17 dogs. All dogs had grossly normal caudal cruciate ligament, medial meniscus, and AC of the medial compartment. In each dog, a complete radial tear of the caudal body of the lateral meniscus was associated with degenerative osteoarthritis (OA) of the lateral compartment of the stifle. The Outerbridge score of the lateral tibial condyle and lateral femoral condyle was 5 of 5 in 15 dogs, 3 of 5 in 1 dog, and 4 of 5 in 1 dog., Conclusion: Dogs with complete tears of the lateral meniscus developed degenerative OA of the lateral compartment of the stifle leading to AC loss and clinical dysfunction., Clinical Significance: Complete lateral meniscal tears may occur as isolated injuries in dogs with a functional CrCL., (© 2018 The American College of Veterinary Surgeons.)

Osteoarthritis (OA) is a chronic, degenerative disease affecting the articular cartilage and subchondral bone that causes pain and inhibits movement. The stifle's joint fibrous capsule contains the synovial membrane, which produces cartilage nutrients. A ruptured cranial cruciate ligament injures the joint and produces OA. Osteoarthritis diagnosis starts with clinical radiographic and ultrasonographic tests, although the latter is not used very much in dog and cat clinics for this purpose. The objective of this study was to establish the correlation among the results of orthopedic, radiographic, ultrasonographic examinations and structural anatomical changes revealed by arthroscopic evaluation to diagnose stifle joint OA and determine risk factors in the dogs affected. Of 44 clinical cases of OA included in the study, 88.64% had ruptured of cranial cruciate ligaments. The correlation between synovial fluid effusion and osteophytosis was of 0.84. It was concluded that there is good diagnostic agreement between synovial fluid effusion and osteophytosis when dealing with stifle joint OA. Risk factors for dogs regarding the development of stifle joint OA included: ruptured cranial cruciate ligaments or patella luxation, female dogs and weight over 10 kg.

Objective: To determine the effect of sliding humeral osteotomy (SHO) on frontal plane thoracic limb alignment in standing and recumbent limb positions., Study Design: Canine cadaveric study., Sample Population: Canine thoracic limbs (n=15 limb pairs)., Methods: Limbs acquired from healthy Labrador Retrievers euthanatized for reasons unrelated to this study were mounted in a limb press and aligned in a standing position followed by axial loading at 30% body weight. Frontal plane radiography was performed in standing and recumbent positions pre- and post-SHO. In the standing position, lateralization of the foot was measured pre- and post-SHO using a textured grid secured to the limb press base plate. Twelve thoracic limb alignment values (mean ± SD and 95% CI) were determined using the center of rotation of angulation (CORA) method were compared using linear mixed models to determine if significant differences existed between limb alignment values pre- or post-SHO, controlling for dog, limb, and limb position., Results: Six of 12 standing or recumbent alignment values were significantly different pre- and post-SHO. SHO resulted in decreased mechanical lateral distal humeral angle and movement of the mechanical humeral radio-ulnar angle, radio-ulnar metacarpal angle, thoracic humeral angle, and elbow mechanical axis deviation toward coaxial limb alignment. In the standing position, the foot underwent significant lateralization post-SHO., Conclusion: SHO resulted in significant alteration in frontal plane thoracic limb alignment. Additional studies are necessary to determine if the changes reported using our ex vivo model occur following SHO in vivo., (© Copyright 2016 by The American College of Veterinary Surgeons.)

Fragmentation of the medial coronoid process (FCP) is an uncommon cause of thoracic limb lameness in toy and small breed dogs. Arthroscopic findings and treatment remains poorly described. The objective of this study was to describe the arthroscopic findings and short-term outcome following arthroscopic treatment in toy and small breed dogs with FCP. Medical records were retrospectively reviewed. Arthroscopic findings were available from 13 elbows (12 dogs). Outcome data ≥4 wk postoperatively were available for nine elbows. Owner satisfaction scores were available for 10 elbows. Common preoperative findings included lameness, elbow pain, and imaging abnormalities consistent with FCP. Displaced FCP was the most common FCP lesion identified. Cartilage lesions at the medial coronoid process were identified in 92.3% of elbows (n = 12), with a median Outerbridge score of 4 (range 1-5). Concurrent cartilage lesions of the medial humeral condyle were identified in 76.9% of elbows (n = 10). Seven of nine elbows had full or acceptable function postoperatively. Median owner outcome satisfaction was 91% (range 10-100). FCP should be considered a cause of thoracic limb lameness in toy and small breed dogs. Arthroscopy can be safely and effectively used to diagnose and treat FCP in these breeds.

Grade 4/4 medial patellar luxation (MPL) is a complex disease of the canine stifle that often requires surgical realignment of the patella to resolve clinical lameness. Outcome following surgery remains poorly described. Medical records were retrospectively reviewed for surgical correction of grade 4 MPL. Signalment and exam findings, surgical procedures performed, complications, and clinical outcome were reported. Data was statistically analyzed for association with major complication occurrence and unacceptable function following surgery. Forty-seven stifles from 41 dogs were included. The surgical procedures most frequently utilized for patellar realignment were the combination of femoral trochleoplasty, tibial tuberosity transposition, and joint capsule modification. Median in-hospital veterinary examination was performed at 69 days (range 30-179 days) following surgery. Full function was reported for 42.6% of cases (n=20). Acceptable function was reported for 40.4% of cases (n=19). Unacceptable function was reported for 17% of cases (n=8). The overall complication rate was 25.5% (n=12), with revision surgery for major complications required in 12.8% of cases (n=6). Corrective osteotomies were associated with major complications (P < 0.001). In general, pelvic limb function improves following surgical correction of grade 4 MPL; however, a return to full function should be considered guarded.

Objective: To compare the biomechanical properties of clamp rod internal fixation (CRIF)/rod and LC-DCP/rod constructs in a canine femoral gap model., Study Design: Cadaveric biomechanical study., Sample Population: Canine femora (n = 10 pair)., Methods: Femora with 40 mm ostectomies were assigned to LC-DCP/rod or CRIF/rod treatment groups. Five construct pairs had 4-point bending and 5 pairs had torsional loading. Construct stiffness, strength, and bending angle at failure or permanent angular deformation (torsional loading) were determined. Statistical comparisons were performed using Student t tests; significance was set at P ≤ .05., Results: There was significantly greater permanent angular deformation, or residual twist, in the CRIF/rod constructs (23.1 ± 0.89°) compared with LC-DCP/rod constructs (7.47 ± 2.08°). Whereas there was no significant difference in torsional stiffness of these constructs at torsional loads <4.92 N m (P = .819), LC-DCP/rod constructs had significantly greater torsional stiffness (0.303 ± 0.079 N m/°) and strength (11.546 ± 2.79 N m) than CRIF/rod construct stiffness (0.06 ± 0.013 N m/°) and strength (6.078 ± 0.527 N m) at torsional loads >4.92 N m. Differences in stiffness and strength in 4-point bending were not statistically significant., Conclusions: LC-DCP/rod constructs had significantly less permanent angular deformation than CRIF/rod constructs. CRIF/rod constructs became less stiff as torsional load was increased, thus the LC-DCP/rod constructs had significantly greater torsional stiffness and strength under high torsional loads. LC-DCP/rod and CRIF/rod constructs performed similarly under 4-point bend loading conditions., (© Copyright 2014 by The American College of Veterinary Surgeons.)

Objective: To report thoracic limb alignment values in healthy dogs; to determine if limb alignment values are significantly different when obtained from standing versus recumbent radiographic projections., Study Design: Prospective cross-sectional study., Animals: Labrador Retrievers (n = 45) >15 months of age., Methods: Standing and recumbent radiographs were obtained and limb montages were randomized before analysis by a single investigator blinded to dog, limb, and limb position. Twelve limb alignment values were determined using the CORA methodology. Measurements were performed in triplicate and intra-observer variability was evaluated by intra-class correlation coefficient (ICC). Limb alignment values were reported as mean ± SD and 95% confidence intervals. Linear mixed models were used to determine if significant associations existed between limb alignment values and limb, limb position, gender, age, weight, and body condition score., Results: There were significant differences in standing and recumbent limb alignment values for all values except elbow mechanical axis deviation (eMAD). Limb, gender, age, body weight, and body condition score had no effect. ICC values ranged from 0.522 to 0.758, indicating moderate to substantial agreement for repeated measurements by a single investigator., Conclusions: Limb alignment values are significantly different when determined from standing versus recumbent radiographs in healthy Labrador Retrievers., (© Copyright 2014 by The American College of Veterinary Surgeons.)

The objective of this study was to develop a surgical technique for sensory denervation of the canine elbow joint and to assess the effects of denervation on limb function in normal dogs. Twenty cadavers (40 elbows) were used to characterize innervation and design the surgical protocol which was tested in 13 cadavers (26 normal elbows). The effect of denervation on limb function was assessed in vivo in four dogs with the elbow randomly selected for the procedure. Primary outcome measures were static bodyweight distribution and distal limb mechanical sensory thresholds; secondary outcome measures were subjectively scored lameness, neurological function and pain on manipulation. Histology was performed on all resected tissues to determine whether nerves had been resected. Denervation was achieved by separate medial and lateral surgical approaches. In testing the developed surgical protocol, 111/130 resected samples contained nerve tissue in the healthy cadaveric elbows and 18/20 in the in vivo study. Limb function and sensation were not altered by elbow joint denervation. The protocol developed for denervation of the canine elbow appears feasible and does not result in any sensory or motor deficits of the forelimb., (Copyright © 2010 Elsevier Ltd. All rights reserved.)

Objective: To describe a surgical technique for placement of a minimally invasive radial plate following application of an ulnar rod (MIPR) for treatment of antebrachial fractures., Methods: Medical records (November 2005-June 2009) were searched to identify dogs with diaphyseal radius and ulna fractures stabilised by MIPR. Data retrieved included signalment, weight, limb affected, cause of injury, open versus closed fracture, number of fragments, implant size, number of screws used and cortices engaged, number of open screw holes, operative time, rod removal, complications and time to radiographic healing. To be included, dogs had to have evidence of radiographic healing during follow-up., Results: Eight dogs with diaphyseal radius and ulna fractures treated with MIPR were included in the case series. All fractures were due to trauma and two fractures were open (grade 1). Rod loosening and osteomyelitis of the ulna occurred in one case which subsequently resolved with rod removal. Healing occurred in all cases with no implant failures. Median time to radiographic union was 10.5 weeks (mean ± SD = 17 ± 15 weeks; range 4-52 weeks)., Clinical Relevance: Use of MIPR constructs on diaphyseal fractures of the radius and ulna is an effective technique for managing these fractures using principles of biological osteosynthesis. An intramedullary rod in the ulna assists with fracture reduction and stabilisation and rod removal is recommended once fracture healing has occurred.

Objective: To document cartilage damage associated with elbow lameness in dogs without radiographic signs., Study Design: Case series., Animals: Dogs (n=16)., Methods: Medical records (November 2004-January 2006) of dogs with undiagnosed forelimb lameness localized to the elbow but without radiographic signs that had lesions identified by either computed tomography (CT) or nuclear scintigraphy and confirmed by arthroscopy were included. Signalment, duration of clinical signs before admission, surgical diagnosis, and treatment were recorded., Results: Sixteen dogs (10 left, 6 right elbows) were identified. Median age was 30.1 months and median duration of clinical signs before admission was 15.6 months. CT or scintigraphy were strongly suggestive of elbow pathology before confirmation by arthroscopy. Medial coronoid pathology was identified in every abnormal elbow and osteochondrosis dissecans in 2 elbows., Conclusions: Elbow pathology not associated with radiographic changes can be identified by CT and scintigraphy. Coronoid pathology is the most likely diagnosis., Clinical Relevance: Absence of radiographic signs in elbows with clinical signs of lameness should be evaluated with advanced imaging techniques (CT, scintigraphy) and arthroscopy to identify the cause of lameness.

Objective: To evaluate the relationship between previously used subjective and objective measures of limb function in normal dogs that had an induced lameness., Study Design: Prospective, blinded, and induced animal model trial., Animals: Normal, adult, and mixed-breed dogs (n=24) weighing 25-35 kg., Methods: Force platform gait analysis was collected in all dogs before and after induction of lameness. All gait trials were videotaped; 60 video trials were evaluated by 3 surgeons with practice limited to small animal orthopedics and 3 first year veterinary students in an effort to establish the relationship between subjective and objective measures of lameness. Evaluators were unaware of the force platform data., Results: Concordance coefficients were low for all observers and were similar between students and surgeons. These values were further decreased when normal and non-weight bearing trials were removed. Agreement with the force platform data was low even when observers only had to be within +/-10% of the ground reaction forces. When repeat trials were evaluated surgeons had a much higher repeatability compared with students., Conclusions: Subjective evaluation of the lameness in this study varied greatly between observers and agreed poorly with objective measures of limb function., Clinical Relevance: Subjective evaluation of gait should be interpreted cautiously as an outcome measure whether performed from a single or from multiple observers.

Objective: To determine the microchemical and surface composition of tibial plateau leveling osteotomy (TPLO) plates before and after explantation., Sample Population: 7 TPLO plates surgically removed from host dogs 6 to 54 months after implantation; 2 raw unpolished-and-unpassivated 316L TPLO plates; and 2 heat-treated, polished-and-passivated, and cleaned 316L TPLO plates., Procedures: Samples were removed by use of standard techniques to ensure the plate surface was not damaged. Sample pieces were dissolved and analyzed by inductively coupled plasma-mass spectrometry (ICP-MS) to determine bulk elemental composition. Other sample pieces were investigated by use of scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), and x-ray photoelectron spectroscopy (XPS) for determination of sample morphology, near-surface elemental composition, and surface elemental composition, respectively. To investigate the possibility of corrosion in situ, some samples were chemically corroded and analyzed., Results: ICP-MS confirmed that elemental composition of samples was consistent with 316L stainless steel. The SEM and EDS analyses revealed trace amounts of polishing materials and a nonuniform carbonaceous biofilm on < 1% of the surface area of samples removed from the host dogs. The XPS analysis indicated an increase in the chromium-to-iron ratio on passivated surfaces, with no difference between passivated samples before implantation and after explantation., Conclusions and Clinical Relevance: Composition of the TPLO plates was consistent with 316L stainless steel. No chemical or topographic changes were detected in TPLO plates that had been implanted in dogs for up to 54 months. A small amount of biofilm was evident on the surface of 2 plates.

Osteochondritis dissecans of the shoulder joint was treated by arthroscopy in 126 dogs. Twenty-four dogs had bilateral surgery, making a total of 150 joints treated. The OCD flaps were removed in small pieces through the cannula or in a single piece through a stab incision. The lameness resolved completely within seven-60 days following arthroscopy in 137 out of 150 affected limbs. Within a subset of 47 dogs with unilateral OCD, it was found that lesions located on the caudo-medial region of the humeral head had a better functional outcome than those lesions located in the caudo-central region of the humeral head.

Objective: To determine outcome for dogs and cats with diaphyseal fractures in which a plate-rod construct was used for fracture repair., Design: Retrospective study., Animals: 35 dogs and 12 cats., Procedures: Medical records and radiographs were reviewed to obtain information concerning signalment, fracture severity, construct design, time to radiographic union, complications, and outcome. Clients were contacted by telephone to obtain information on complications, limb usage, and overall satisfaction with the procedure., Results: 31 femoral, 9 humeral, and 7 tibial fractures were assessed. Thirteen fractures consisted of 2 fragments, 22 consisted of 3 to 5 fragments, and 12 consisted of > 5 fragments. Forty-six of 47 (98%) fractures reached union. Mean +/- SD times to radiographic union were 7.5 +/- 2.7 weeks for the dogs and 4.8 +/- 1.3 weeks for the cats. There were 4 short-term, minor complications and 15 long-term complications (2 major and 13 minor). Owners of 21 of 30 dogs (70%) and 9 of 12 cats reported that their animals had normal limb function. Twenty-six of 28 dog owners (93%) and 12 of 12 cat owners indicated that they were satisfied with results of the procedure. As surgery time increased, time to union also increased. Time to union for fractures with > 5 fragments was significantly shorter than time to union for fractures with < or = 5 fragments., Conclusions and Clinical Relevance: Results suggest that plate-rod constructs can successfully be used for repair of diaphyseal fractures of a wide range of severity in dogs and cats.

Objective: To evaluate the effect of tibial plateau leveling on joint motion in canine stifle joints in which the cranial cruciate ligament (CCL) had been severed., Study Design: In vitro cadaver study., Animals: Six canine cadaver hind legs., Methods: Radiographs of the stifle joints were made to evaluate the tibial plateau angle with respect to the long axis of the tibia. The specimens were mounted in a custom-made testing device to measure cranio-caudal translation of the tibia with respect to the femur. An axial load was applied to the tibia, and its position was recorded in the normal stifle, after transection of the CCL, and after tibial plateau leveling. Further, the amount of caudal tibial thrust was measured in the tibial plateau leveled specimen while series of eight linearly increasing axial tibial loads were applied., Results: Transection of the CCL resulted in cranial tibial translation when axial tibial load was applied. After tibial plateau leveling, axial loading resulted in caudal translation of the tibia. Increasing axial tibial load caused a linear increase in caudal tibial thrust in all tibial plateau-leveled specimens., Conclusions: After tibial plateau leveling, axial tibial load generates caudal tibial thrust, which increases if additional axial load is applied., Clinical Relevance: Tibial plateau leveling osteotomy may prevent cranial translation during weight bearing in dogs with CCL rupture by converting axial load into caudal tibial thrust. The amount of caudal tibial thrust seems to be proportional to the amount of weight bearing., (Copyright 2002 by The American College of Veterinary Surgeons)

Objective: To evaluate effects of intra-articular and extracapsular reconstruction of the cranial cruciate ligament (CCL) on metabolism of articular cartilage as reflected by concentrations of chondroitin sulfate epitopes 3B3 and 7D4 in synovial fluid., Animals: 13 adult dogs., Procedure: Each dog underwent unilateral CCL transection (CCLT). One month after CCLT, sham CCL reconstruction (3 dogs), intra-articular CCL reconstruction (5), or extracapsular CCL reconstruction (5) was performed. Synovial fluid was collected by direct arthrocentesis from CCLT and contralateral stifle joints immediately before (time 0) and 1, 3, and 5 months after CCLT. Fluid was examined for concentrations of 3B3 and 7D4 epitopes and total sulfated glycosaminoglycan (GAG) content., Results: Concentrations of 3B3, 7D4, and GAG, 3B3:GAG, or 7D4:GAG in CCLT joints did not differ significantly among treatment groups nor in the ratios of these variables in CCLT joints to contralateral joints at 3 months. In a longitudinal analysis, concentrations of 3B3 and 7D4, 3B3:GAG, and 7D4:GAG in CCLT joints in all groups changed significantly with time, but we did not detect time X group interactions., Conclusions and Clinical Relevance: Transection of CCL resulted in significant perturbation in articular cartilage metabolism as reflected by alterations in concentrations of 3B3 and 7D4 in synovial fluid. These changes over time were not significantly influenced by method of CCL reconstruction. We did not find evidence that surgical stabilization of CCL-deficient joints by intra-articular or extracapsular techniques had any effect on preventing alterations in composition of synovial fluid that have been associated with secondary osteoarthritis.

Objective: To evaluate effects of an orally administered mixture of chondroitin sulfate, glucosamine hydrochloride and manganese ascorbate (CS-G-M) on articular cartilage metabolism in dogs with cranial cruciate ligament (CCL) deficient and reconstructed knees, as reflected by concentrations of synovial fluid 3B3, 7D4 and total sulfated glycosaminoglycan (GAG)., Methods: Sixteen adult dogs that underwent unilateral CCL transection were randomized into four groups. Thereafter, group I (N=3) had a sham CCL reconstruction, group II (N=3) had CS-G-M and sham CCL reconstruction, group III (N=5) had CCL reconstruction, and group IV (N=5) had CS-G-M and CCL reconstruction. Synovial fluid collected at 0, 1, 3 and 5 months was examined by ELISA for 3B3 and 7D4 epitope, and by DMMB assay for total GAG., Results: Synovial fluid from CCL transected knees of CS-G-M treated dogs contained significantly elevated concentrations of 3B3 (P=0.029), 7D4 (P=0.036) and 7D4/GAG (P=0.007) in comparison to controls, in a cross-sectional analysis at 3 months. Furthermore, 7D4 and 7D4/GAG concentrations remained significantly elevated (P=0.012) in CCL transected knees of CS-G-M treated dogs over the 5 month period. However, when epitope concentrations were expressed as a ratio of CCL-transected to contralateral non-operated knee, treatment effect of CS-G-M was no longer significant. Reconstruction of the CCL had no significant effect on synovial fluid epitope., Conclusions: Administration of CS-G-M was associated with altered concentrations of 3B3 and 7D4 epitope in synovial fluid, suggesting that these compounds may act to modulate articular cartilage matrix metabolism in vivo.

We compared the pin-bone interfaces at the near and far cortical penetration sites of positive-profile end-threaded external fixation pins in cadaveric canine tibiae. The holding power of the pins in each cortical surface was independently measured in 21 pin-bone sections. Scanning electron microscopy (SEM) was used to compare subjectively the microstructural appearance of the pin-bone interfaces at the near and far cortical penetration sites in eight pin-bone sections. The far cortical penetration site provided greater holding power than did the near cortical site. SEM evaluation suggested more bony microfractures and debris with less pin-bone SEM evaluation suggested more bony microfractures and debris with less pin-bone interlock in the near cortical penetration sites than in the corresponding far cortical penetration sites. This study showed that after low-speed power insertion of positive-profile end-threaded pins in canine cadaveric tibiae, the near cortical penetration site contributes approximately 25% less to the overall holding power of the pin than does the far cortical penetration site.

We evaluated the in vivo animal tolerance to intraosseous infusion via the Osteoport pediatric implant (model 2005PSO, Lifequest Medical, San Antonio, TX, U.S.A.) into the proximal tibia of immature goats and investigated the osseous effects of intermittent and sustained increases in intraosseous pressure (IOP). In group 1 (n = 3) autogenous whole blood was continuously infused (CI) for 5 days at flow rates producing an IOP of 30-45 mm Hg. Group 2 animals (n = 3) underwent a 5-s high-pressure infusion (HPI) of lactated Ringer solution (LRS) producing an IOP of 90-125 mm Hg twice daily for 10 days. In group 3, the Osteoports were left in place 5 (n = 2) or 10 days (n = 2) and evaluated for patency at 72-h intervals. An IOP > 35 mm Hg produced clinical evidence of bone pain. Bone mineral density was significantly increased (p < 0.05) in all implanted tibias (mean 1.04 g/cm2; range 0.87-1.21 g/cm2) compared with controls (mean 0.67 g/cm2; range 0.65-0.71 g/cm2). A nonsignificant increase (+9% to +31%) in periosteal new bone formation occurred in all implanted tibias. In the continuously infused group, there was a significant increase (p < 0.05) in cancellous new bone formation (+483%), percentage eroded bone surface (+143%), and osteoclast covered bone surface (+255%) compared with controls. HPI of LRS did not produce significant bone changes. Seemingly, the Osteoport provided a ready means of intraosseous infusion and may be associated with less complications than current methods of continual vascular access. Bone changes correlated more with the duration than the magnitude of increased intraosseous pressures.

Distraction osteogenesis was used to treat five dogs with limb deformities or limb shortening. The affected bones underwent osteotomy, and modified external fixators were attached. Complications included pin loosening, implant breakage, and soft-tissue contracture. Adequate limb length was attained in all cases, but clinical results varied from poor to excellent. Two dogs were not lame after the procedure, two dogs had improved function but were still lame, and one dog had complications necessitating amputation.

External skeletal fixation is being used to treat an increasing number of orthopedic conditions in veterinary medicine. Study of the variables affecting the biomechanics of external fixation and bone healing is vital if patient morbidity is to be minimized. These are reviewed and incorporated into strategies that can be applied to decision making using external fixation in the clinical setting.

Twenty-three canine pelves were tested bilaterally to determine the stiffness and strength of intact ilium and stabilized oblique iliac osteotomies that simulated a common clinical fracture. Fixation systems tested were three 4.0 mm cancellous screws inserted ventral to dorsal across the osteotomy site and one laterally placed five hole 3.5 mm dynamic compression plate. Specimens were mechanically tested to failure under torsional, axial, or axial plus bending loads. Lag screw fixation was stiffer and stronger than plate fixation in all testing modes. The differences were statistically significant (p less than .05) in the torsional and axial plus bending loading modes. Fatigue testing was performed on implanted specimens with low-level cyclic loading under axial plus bending loading conditions. Physiologic loading conditions failed to produce mechanical failure of either fixation system after 100,000 cycles.

Five dachshunds were treated for a distal varus deformity of one tibia. Angulations of 20 degrees to 30 degrees resulted from shortening of the medial tibial length with the maximum curvature at the distal metaphysis. Comparison with the contralateral limbs was required to determine the amount of correction necessary for functional and cosmetic results. Open wedge osteotomies stabilized with a modified type II external fixator resulted in correction of the deformities, early return of limb function, and healing of the osteotomies.

Abnormal carpal configuration was observed in a litter of ten 2-month-old pups raised in a research colony. Five of the pups were exercised daily, and carpal configuration returned to normal within 7 to 10 days. The other 5 pups remained confined, and their carpal configuration returned to normal after 6 weeks. It was concluded that poor muscle tone was responsible for the carpal hyperextension.

A surgical approach that offered direct visualization and removal of the hypophysis was evaluated in 17 dogs. Ten of the dogs were euthanatized and used to identify reliable landmarks for the drill site in the basisphenoid bone to expose the hypophysis. The intersphenoidal suture was an accurate landmark in that 1 cm caudal to the intersphenoidal suture was determined to be the precise point for the center of the drill hole. The remaining 7 dogs were hypophysectomized, using this approach. The landmarks were accurate, the surgery had a high degree of safety, and all hypophyses were removed.

Biomechanical analysis was performed on the cranial cruciate ligament (CCL) and three autogenous tissues used for CCL reconstruction in the canine stifle. The autogenous tissues were patellar ligament-based autografts described for over-the-top CCL replacement and included the central one third of the patellar ligament, the medial one third of the patellar ligament, and the lateral one third of the patellar ligament with fascia lata. Tension testing produced abrupt failure of the central and medial autografts but sequential failure of the lateral autograft. Structural properties were determined for the overload condition and within the load range of normal activity for the CCL (physiologic range). None of the autograft systems approached the stiffness, maximum load, and energy absorbed to maximum load of the CCL. The central and lateral autografts were stiffer, had greater maximum loads, and absorbed more energy to maximum load than the medial autograft. The central and lateral autografts had an elastic range, as defined by proportional limit, which corresponded to the physiologic range of loading for the CCL. Loads that corresponded to physiologic displacement of the lateral and central autografts were near the maximum load of the fixation site, which underscored the need for postoperative support of the repaired stifle.

Sixteen normal 20 to 30 kg dogs had standard femoral head and neck excision (8 dogs) or femoral head and neck excision with interposition of a biceps muscle flap (8 dogs). Lameness lessened at week 6, and did not differ between groups; neither group returned to a completely normal gait. Weightbearing decreased on the operated pelvic limb compared to controls (forceplate analysis). Weightbearing force of the muscle flap dogs was significantly less at weeks 6 and 16 than that of the standard femoral head and neck excision dogs. The operated limb of both groups was shortened; shortening was significantly greater for the muscle flap group. Hip extension was limited in both groups. Both groups had decreased (more acute) hip, stifle, and hock angles measured in standing position. Thigh muscle atrophy was more pronounced in the muscle flap group at week 6. More soft tissue was interposed in the muscle flap group at necropsy compared to the group with standard femoral head and neck excision, but the difference was not statistically significant. Skeletal muscle fibers were present in the interposed fibrous connective tissue of the muscle flap group, and the healed surfaces were smoother than those of the standard femoral head and neck excision group.