Combined center of rotation of angulation-based leveling osteotomy and tibial tuberosity transposition: An ex vivo mechanical study.

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.

Center of rotation of angulation-based leveling osteotomy for stifle stabilization in skeletally immature dogs.

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.

The significance of the meniscal flounce sign in canine stifle arthroscopy.

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.

Center of rotation of angulation-based leveling osteotomy combined with a coplanar cranial closing wedge ostectomy to manage cranial cruciate ligament insufficiency in dogs with excessive tibial plateau angle.

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.

Articular cartilage lesions associated with complete lateral meniscal tears in the dog.

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.

Correlation between osteoarthritic changes in the stifle joint in dogs and the results of orthopedic, radiographic, ultrasonographic and arthroscopic examinations.

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.

The Effect of Sliding Humeral Osteotomy (SHO) on Frontal Plane Thoracic Limb Alignment: An Ex Vivo Canine Cadaveric Study.

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.

Fragmentation of the Medial Coronoid Process in Toy and Small Breed Dogs: 13 Elbows (2000-2012).

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.

Outcome Following Surgical Correction of Grade 4 Medial Patellar Luxation in Dogs: 47 Stifles (2001-2012).

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.

In vitro biomechanical comparison of 3.5 mm LC-DCP/intramedullary rod and 5 mm clamp-rod internal fixator (CRIF)/intramedullary rod fixation in a canine femoral gap model.

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.

Thoracic limb alignment in healthy labrador retrievers: evaluation of standing versus recumbent frontal plane radiography.

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.

Elbow denervation in dogs: development of an in vivo surgical procedure and pilot testing.

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.

Arthroscopic documentation of elbow cartilage pathology in dogs with clinical lameness without changes on standard radiographic projections.

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.

Use of a plate-rod construct and principles of biological osteosynthesis for repair of diaphyseal fractures in dogs and cats: 47 cases (1994-2001).

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.