Medial Patellar Luxation in 16 Large Dogs A Retrospective Study

Unilateral medial patellar luxation was diagnosed in 10, and bilateral medial patellar luxation in six, large and giant-breed dogs (22 stifles). Lameness occurred in five dogs after trauma or surgery, and 11 dogs had no known predisposing history. The mean age at presentation was 25 months, and the mean time from initial onset of clinical signs to diagnosis was 13 weeks. All traumatic or iatrogenic luxations (five dogs) were unilateral. Luxations presumed to be congenital were unilateral in five dogs and bilateral in six. The grades of medial patellar luxation were I (1 stifle), II (11 stifles), III (9 stifles), and IV (1 stifle). Preoperative function was good (1 dog), fair (9 dogs), and poor (6 dogs). Surgical correction was performed in dogs with grades II, III, and IV luxations (21 stifles). Complications included one wound dehiscence and trochlear wedge migration, one pin loosening, and one persistent lameness caused by lymphoplasmacytic synovitis. Long-term follow-up was available in 13 dogs (18 stifles). Function was judged by owners to be excellent in seven dogs, good in five dogs, and poor in one dog. Surgical treatment of grades II and III luxations yielded good (8 stifles) and excellent (9 stifles) results, while one grade IV luxation had a poor long-term outcome.     

Mechanoreceptors in the Anterior Horn of the Equine Medial Meniscus: an Immunohistochemical Approach

Lameness due to stifle and especially meniscal lesions is frequent in equine species. In humans, mechanoreceptors involved in proprioceptive function are well studied. Given the high incidence of meniscal injuries in horses, and the lack of information concerning them in equine menisci, our objective was to study these corpuscles in six healthy anterior horns of the equine medial meniscus, which is the most common localisation reported for equine meniscal injuries. Immunohistochemical stainings were performed using antibodies against high molecular weight neurofilaments and glial fibrillary acidic proteins. From a purely fundamental point of view, our work highlights for the first time the presence of Ruffini, Pacini and Golgi corpuscles in equine meniscus. They were found, isolated or in clusters and always located at the vicinity of blood vessels, at the level of the anterior horn of the equine medial meniscus. This morphological approach could serve as a basis for clinical studies, to evaluate the impact of these corpuscles on the poor sportive prognosis in equine meniscal tears.     

A Simple Clearance Test for the Assessment of Renal Function in Dogs

Abstract—A simple renal clearance technique has been investigated. This involves a single intravenous injection of a mixture of inulin and p-aminohippuric acid (PAH), the withdrawal of two blood samples and subsequent estimation of the concentration of both injected substances. The rates of fall in plasma concentrations of these were related to kidney function as assessed by biochemical, clinical, and when possible, pathological methods. Forty-four cases were investigated, in five of these the test was repeated in an attempt to assess change in kidney function, seven dogs showed no biochemical abnormality, and twelve were ultimately examined at post mortem. In addition, serial studies over approximately 1 yr were made on three normal dogs in an attempt to derive normal elimination rates. It has been demonstrated that the test has a possible use in prognosis, but appears to be less sensitive than other methods for the detection of mild nephritis. Résumé—Une simple technique de nettoyage rénal a été investiguée. Celle-ci comporte une seule piqǔre intraveineuse d'un mélange d'inuline et d'acide aminohippurique-p (PAH), la rétratcion de deux échantillons de sang, et une estimation conséquente de la concentration des deux substances injectées. Le taux de diminution dans les concentrations de plasma de ceux-ci a été associé au fonctionnement des reins comme établi par les méthodes biochimiques, cliniques et si possible, pathologiques. Quarante quatre cas ont été investigués, dans cinq de ces derniers le test été répété dans le but d'évaluer les changements dans le fonctionnement des reins, sept chiens n'ont démontré aucun anomalie biochimique, et douze ont été en dernier lieu examinés en post mortem. De plus, des séries d'études de plus d'un an ont été faites sur trois chiens normaux dans une tentative de dériver les degrés d'élimination normale. 11 a été démontré que le test a une place possible dans la prognose, mais semble étre moins sensitif que d'autres méthodes pour la détection de légères nephrites. Zusammenfassung—Eine einfache Nierenreinigungsmethode wurde untersucht. Es handelte sich dabei um eine einzige intravenöse Injektion mit einer Mischung von inulin and p-aminohippurischer Säure (PAH), die Entziehung zweier Blutproben und darauffolgende Schätzung der Konzentration dieser beiden injizierten Substanzen. Das Ausmass der Senkung in Plasmakonzentration dieser Substanzen wurde auf Veränderung in der Nierenfunktion bezogen, welche durch biochemische, klinische und, wo durchführbar, durch pathologische Methoden bestimmt worden waren. Man untersuchte vierundvierzig Fälle, wobei bei fünfen der Test wiederholt wurde, um Versuche zur Abschätzung der Nierenfunktionsveränderungen anzustellen. Sieben Hunde zeigten keine biochemis-chen Abnormalitäten und bei zwölf Hunden wurde letzten Endes eine post mortem Untersuchung angestellt. Ausserdem wurden noch Serienstudien während ungefähr eines Jahres an drei normalen Hunden zum Versuche der Ergründung normaler Eliminierungsgrade gemacht. Es wurde bewiesen, dass dieser Test eine Verwendungsmöglichkeit bei Prognosen bietet, jedoch weniger sensitiv als andere Methoden zur Feststellung von leichter Nepthritis zu sein scheint.     

Medial Plating for the Repair of Middle and Distal Diaphyseal Fractures of the Humerus in Dogs

Six middle and distal humeral shaft fractures in dogs were repaired by the application of a bone plate along the medial shaft of the humerus. In all animals, clinical and radiographic evidence of normal bone healing was observed. The bone plate and ancillary implants were removed from five dogs by 10 months. In none of the six dogs were any untoward effects of placing the bone plate along the medial shaft of the humerus detected nor were there any difficulties encountered with the medial humeral soft tissues.     

Determination of Safe Depth of Pin Penetration for Repair of Distal Femoral Physeal Fractures in Immature Dogs: A Comparison of Normograde and Retrograde Pin Placement

Objective —The purpose of this study was to determine the depth that implants may be safely placed into the distal femoral epiphysis (DFE) for the repair of distal femoral physeal fractures.
Study Design —The depth of the DFE was related to the radiographic thickness of the patella in this experimental study.
Animals or Sample Population —Twenty immature canine cadavers.
Methods —Patella thicknesses were measured from lateral radiographs. Actual DFE depths were determined for pins driven in normograde fashion and for pins driven retrograde from the central depression between the metaphyseal pegs and from the cranial pegs. The association of DFE depth and patella thickness was evaluated using linear regression analysis. Using 95% confidence intervals, rules for estimating the safe depth of implant placement into the DFE were determined.
Results —DFE depth had significant correlation with patella thickness for pins placed in retrograde fashion from the central depression between the metaphyseal pegs (r²= .83) and from the cranial pegs (r²= .82) and for pins placed in normograde fashion (r²= .65).
Conclusions —Based on 95% confidence intervals, pins placed in retrograde fashion from the central depression between the metaphyseal pegs may be safely driven into the DFE a distance equal to 140% of patella thickness. Pins placed from the cranial metaphyseal pegs may be driven to a depth equal to 80% of patella thickness, and pins placed in normograde fashion may be driven to a depth equal to 30% of patella thickness.
Clinical Relevance —Measurement of patella thickness assists the surgeon in determining the approximate depth that pins may be driven into the DFE without penetrating the articular surface of the stifle joint.     

Clinical Results of Surgical Correction of Medial Luxation of the Patella in Dogs

Thirty-four dogs that had surgical correction of medial patellar luxation (MPL) in 52 stifle joints were examined after a minimum follow-up period of 1 year (median, 3.6 years). The dogs were divided into the following three groups depending on their age at the time of surgery: group 1, 3 to 6 months; group 2, 8 to 20 months; and group 3, 2.2 to 12 years. Two of the dogs in group 3 had ruptured their cranial cruciate ligament in addition to having MPL. The results were based on a clinical assessment of the animal's gait, and physical and radiographic examination of the stifle joints. Six of seven stifle joints evaluated in group 1 had radiographic evidence of moderate to severe degenerative joint disease of the patellofemoral joint, and in two of the joints recurrence of MPL was observed. Failure to maintain reduction of the patellofemoral joint was also observed in 11 of 22 (50%) and 12 of 23 (52%) of the stifle joints in groups 2 and 3, respectively. In the latter groups, mild degenerative joint disease was evident radiographically in stifle joint that had not maintained reduction. Four of the 34 dogs were consistently (n = 2) or intermittently (n = 2) lame; the two dogs that were consistently lame had cranial instability of the stifle consistent with rupture of the cranial cruciate ligament. In the latter two dogs, the cranial cruciate ligament had been intact at the time of surgery for correction of MPL.     

Arthroscopic Study of Cranial Cruciate Ligament and Medial Meniscal Lesions in the Dog

Twenty stifles (10 dogs) were studied for a period of 1 year after various lesions of the cranial cruciate ligament and medial meniscus were produced surgicaoy. Through serial arthroscopic evaluations, degenerative processes In stifles with a "torn" cranial cruciate ligament were documented. Intra-articular changes were minimal after partial meniscectomy and were severe after total meniscectomy. Multiple arthroscopies caused no demonstrable changes.     

Folding of the Caudal Horn of the Medial Meniscus Secondary to Severence of the Cranial Cruciate Ligament

Folding of the caudal horn of the medial meniscus after surgical severence of the cranial cruciate ligament was investigated. When the stifle was flexed and the tibia was placed in a cranial position, the caudal horn of the medial meniscus could move forward without damaging the meniscus or the caudal joint capsule. Forward movement of the tibia with the stifle extended could damage the meniscus and/or the joint capsule. Abnormal position of the meniscus did not necessarily indicate meniscal damage.     

A Review of Paclitaxel and Novel Formulations Including Those Suitable for Use in Dogs

Paclitaxel is a commonly used chemotherapeutic agent with a broad spectrum of activity against cancers in humans. In 1992, paclitaxel was approved by the U.S. Food and Drug Administration (FDA) as Taxol^® for use in advanced ovarian cancer. Two years later, it was approved for the treatment of metastatic breast cancer. Paclitaxel was originally isolated from the bark of the Pacific yew tree, Taxus brevifolia in 1971. Taxanes are a family of microtubule inhibitors. As a member of this family, paclitaxel suppresses spindle microtubule dynamics. This activity results in the blockage of the metaphase‐anaphase transitions, and ultimately in the inhibition of mitosis, and induction of apoptosis in a wide spectrum of cancer cells. Additional anticancer activities of paclitaxel have been defined that are independent of these effects on the microtubules and may include the suppression of cell proliferation as well as antiangiogenic effects. Based on its targeting of a fundamental feature of the cancer phenotype, the mitotic complex, it is not surprising that paclitaxel has been found to be active in a wide variety of cancers in humans. This review summarizes the evidence in support of paclitaxel's broad anticancer activity and introduces the rationale for, and the progress in development of novel formulations of paclitaxel that may preferentially target cancers and that are not associated with the risks for hypersensitivity in dogs. Of note, a novel nanoparticle formulation of paclitaxel that substantially limits hypersensitivity was recently given conditional approval by the FDA Center for Veterinary Medicine for use in dogs with resectable and nonresectable squamous cell carcinoma and nonresectable stage III, IV and V mammary carcinoma.     

A Retrospective Evaluation of Stifle Osteoarthritis in Dogs with Bilateral Medial Patellar Luxation and Unilateral Surgical Repair

The effects of surgical and nonsurgical therapy on the development of osteoarthritis were compared in 12 dogs with bilateral medial patellar luxation and unilateral surgical repair. Evaluations included severity of lameness and patellar luxation, ligamentous stability, range of motion, and radiographic evidence of osteoarthritis before surgery and at a mean of 33 months after surgery. Stifles without surgical treatment served as controls for the contralateral stifles with surgery. All stifles treated surgically had reduced patellofemoral joints, normal range of motion, and improved limb use. Osteoarthritis progressed significantly and comparably in both groups of stifles. Progression of osteoarthritis was not correlated with luxation grade, body weight, or interval from surgery to follow-up. Age at surgery was correlated positively with severity of osteoarthritis in the stifles treated surgically.     

Replacement of the Medial Collateral Ligament with Polypropylene Mesh or a Polyester Suture in Dogs

The medial collateral ligament of one stifle in 20 adult dogs was excised and replaced with polypropylene mesh or a polyester suture. After 26 weeks, the fibrous tissue-prosthesis composites were evaluated clinically, morphologically, and biomechanically. Clinical lameness was not significantly different after 10 days. The polypropylene mesh reconstructions consistently had more fibrous tissue and greater collagenous ingrowth than the polyester suture reconstructions. There were four complications related to fixation of the polypropylene mesh prosthesis and one to the polyester suture. The polypropylene mesh reconstructions had greater stability and were biomechanically more similar to the natural ligaments than the polyester suture reconstructions. Although the results with polypropylene mesh were favorable, more challenging biomechanical testing and alternative anchoring techniques are required before polypropylene mesh can be recommended as a collateral ligament replacement in dogs.