Donald A. Hulse

Relationship between objective and subjective assessment of limb function in normal dogs with an experimentally induced 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.

Principles of bone healing and biomechanics of external skeletal fixation.

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.

Meniscal injury following initial cranial cruciate ligament stabilization surgery in 26 dogs (29 stifles)

OBJECTIVE To describe clinical signs, arthroscopic findings, and outcome in a group of dogs undergoing second look arthroscopy for the treatment of meniscal tears following original surgery to correct a CCL deficient stifle joint. METHODS The medical records of 26 dogs from the Veterinary Teaching Hospital at Texas A&M University and the Veterinary Orthopedic Center (Round Rock, Texas) that had second look arthroscopy for lameness following an original surgical procedure were reviewed. Pre-operative clinical findings, 2nd look arthroscopic findings and owner assessed outcome were documented. RESULTS Postliminary bucket handle tears of the medial meniscus were detected in 22 (75.9%) cases. Other postliminary meniscal injuries included frayed caudal horn tears of the medial meniscus 6 (20.7%), and longitudinal tears of the lateral meniscus 1 (3.4%). An audible or palpable click was present in 27.6% of cases. An improvement or resolution of lameness was reported in 96.5% of cases reported. In conclusion, tears of the medial meniscus are a significant cause of lameness in dogs subsequent to surgery for cranial crucial ligament ruptures. Increased lameness or acute onset of lameness after surgery for cranial crucial rupture is a consistent finding. In rare cases, a palpable or audible click will be appreciated. Arthroscopic evaluation and partial meniscectomy improve or resolve lameness in the majority of cases. CLINICAL SIGNIFICANCE Sudden or increased lameness in dogs with historical CCL stabilization surgery should be evaluated and treated arthroscopically for postliminary meniscal injury if another cause for lameness can not be determined.

A review of osteoarthritis and obesity: current understanding of the relationship and benefit of obesity treatment and prevention in the dog

Obesity is an increasingly important health problem for both man and dog. Osteoarthritis (OA) is a significant cause of pain and disability in both species. A link between obesity and OA has been established in man, though the exact mechanism of the relationship remains to be fully elucidated - current research supports both biomechanical and biochemical theories. There is good evidence (class I*) to support weight loss as an effective treatment for human knee OA. In the dog, the relationship is just beginning to be investigated. The results of one study in dogs (class IV evidence*) suggest that preventing the development of overweightness and obesity reduces the prevalence of hip dysplasia and OA of the hip and other joints. Three other studies (class III and IV evidence*) support weight loss as an effective treatment for OA in affected overweight and obese dogs. Further research could yield greater understanding of the pathophysiology of this relationship, perhaps identifying novel therapeutic targets. Confirmation and better understanding of the positive effect of treating and preventing obesity on symptoms and prevalence of OA is likely to be valuable in the campaign against canine obesity.

Determination of isometric points for placement of a lateral suture in treatment of the cranial cruciate ligament deficient stifle

Complete or partial rupture of the cranial cruciate ligament (CCL) is a common injury of the canine stifle. While numerous techniques have been developed for surgical treatment, extra-articular methods with placement of a lateral suture remain a popular treatment method. The purpose of this study was to determine the potential isometry of the six suture-paired sites; two on the femur and three on the tibia. In six femoro-tibial specimens with intact passive joint restraints, femoral sites adjacent to the proximal (F1) and distal (F2) poles of the fabella, and tibial sites adjacent to the patella insertion (T1), immediately cranial to (T2) and caudal to (T3) the long digital extensor tendon, were identified. A suture from one femoral site to one tibial site was placed under 0 or 5 N of preload, and tension was measured at joint angles of 150 degrees , 130 degrees , 90 degrees and 50 degrees . The F2-T3 combination was found to be most isometric. Isometry was re-assessed in the same specimens with the suture in the F2-T3 position, and under 5 N, 10 N and 15 N of preload, and after transection of the CCL. The suture pair retained its isometric pattern in the CCL transected specimens. There was no effect of preload on isometry patterns.

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

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

Radiographic outcome and complications of tibial plateau leveling osteotomy stabilized with an anatomically contoured locking bone plate: Outcome of TPLO With a Locking Bone Plate

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

Microchemical and surface evaluation of canine tibial plateau leveling osteotomy plates

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.

Investigation of the loss of holding power in the near cortex due to shearing of the bond thread

External skeletal fixation has many uses in the area of orthopedics in both human and veterinary medicine. The success of a procedure utilizing a fixator directly relates to the strength of the pin-bone interface. Prior in vitro study has shown that for a two-cortex, end-threaded pin the far cortex is 1.67 times stronger than the near cortex due to mechanical destruction of the near pin-bone interface. Several factors are believed to contribute to the overall loss of holding power in the near cortex. The purpose of this study was to investigate one area that contributes significantly to the reduction in the near cortex pullout strength, the destruction of the interface due to stripping of the bone threads by the pin as it is temporarily restrained from linear advancement by the far cortex. The results of this study focus attention on the cutting tip of the pin. If the pin can fully engage bone and advance at the rate determined by the threads cut into the near cortex within two and a half pin rotations, the holding power of the near cortex will approach that of the far cortex.<<ETX>>