SummaryThe objective of this study was to determine whether the non-steroidal anti-inflammatory drug (NSAID) carprofen causes adverse histological changes to cartilage after prolonged administration for treatment of naturally acquired osteoarthritis.Dogs diagnosed with cranial cruciate ligament rupture and secondary osteoarthritis of their stifle joints were divided into two groups: those who had received a standard dose of carprofen for a minimum of four weeks and those who had not received a NSAID for a minimum of one month. Cartilage from the intercondylar notch was obtained when the patients underwent surgical procedures to stabilize the stifle joint. The samples were processed and evaluated for histological differences using haematoxylin and eosin and safranin-O-fast green-iron haematoxylin stains and were graded according to a Mankin scale (graded 0-14) for osteoarthritis.The histopathological findings were variable and included loss of matrix staining, irregularities to the cartilage surface, matrix fragmentation, chondrocyte clustering, matrix degeneration and vascular and synovial invasion (pannus) and were not specific to either group. There was not any significant difference between study groups (p = 0.2721) according to the Wilcoxan rank sum test.

OBJECTIVE:To determine whether histopathologic changes are detectable in grossly normal medial menisci from dogs with rupture of the cranial cruciate ligament (CCL). DESIGN:Case series. SAMPLE POPULATION:40 medial menisci from dogs with rupture of the CCL and 20 medial menisci from control dogs without stifle joint disease. PROCEDURE:Data evaluated included age, duration of clinical signs, and whether rupture of the CCL was complete or incomplete. Three groups (n = 20/group) were also compared on the basis of 5 histologic criteria; group-1 menisci appeared grossly normal and were obtained from dogs with naturally occurring rupture of the CCL, group-2 menisci were grossly abnormal and were also obtained from dogs with naturally occurring CCL ruptures, and group-3 menisci were collected at postmortem from dogs without stifle joint disease that were of similar age and weight as dogs in groups 1 and 2. RESULTS:Group-2 menisci were significantly different from group-1 and -3 menisci in all histologic criteria. Group-1 menisci were significantly different from control menisci in only 1 of the 5 histologic criteria (cartilage differentiation). Dogs that were > or =3 years old had significantly more surface cellularity than did dogs that were < 3 years old. A significant difference was not detected between groups 1 and 2 with regard to completeness of rupture. CONCLUSIONS AND CLINICAL RELEVANCE:Histologic changes in meniscal cartilage correlate with gross appearance of the cartilage at time of surgery for rupture of the CCL. On the basis of minimal histologic changes, routine removal of grossly normal menisci does not appear to be warranted.

In dogs surgically treated for biceps tenosynovitis, the most common histopathological findings were fibrosis and collagen degeneration (n=13), synovial villous or vascular hyperplasia (n=10), lymphocytic-plasmacytic infiltrates (n=10), cartilaginous metaplasia (n=8), and ischemic necrosis (n=5). Degree of histopathological changes was associated with degree (p equals 0.000), but not duration (p equals 0.543), of lameness. Furthermore, there was no association between histopathological changes and age or radiographic and arthrographic findings. Cartilage metaplasia was the only histopathological finding in both affected tendons (8/18) and normal control dogs (13/13). Age and size of the control dogs were not determined; however, since all these dogs were clinically normal, fibrocartilaginous metaplasia can be present as an incidental finding in the biceps tendon of origin in dogs.

SummaryA method of closed implantation of a toggle pin bone anchor and prosthetic ligament was developed for the treatment of traumatic canine coxofemoral luxation. Radiographic and anatomical evaluation of the canine femur and acetabulum were performed in order to develop an imaging and instrumentation technique that would allow closed placement of a toggle pin bone anchor under fluoroscopic guidance, while at the same time minimizing, or eliminating, damage to the articular cartilage. The surgical technique was then performed in 14 canine cadaver coxofemoral joints, followed by gross evaluation of implant placement, and potential cartilage or soft tissue damage. The cervical canal radiographic view of the proximal femur allowed placement of the drill hole through the fovea capitis of the femoral head without damaging the articular cartilage. The acetabular fossa was readily distinguishable from the acetabular articular cartilage on both of the lateral and ventrodorsal radiographic views of the pelvis. The toggle pin apparatus was inserted without damage to the articular cartilage in nine out of the fourteen hips and the bone tunnels were situated within the cancellous bone of the femoral neck in each of the nine specimens evaluated. Complications encountered during the procedure included bending and/or breakage of the guide wire in three hips and damage to the articular cartilage in two hips. The success of technique modifications designed to diminish the incidence of these complications awaits investigation in a clinical trial. Closed toggle pinning for canine traumatic coxofemoral luxation has the potential advantage of achieving rapid stabilization of the coxofemoral joint without damage to the articular cartilage and the need for an open approach to the joint. The clinical application of the technique is reported in one patient.The equipment and methodology for closed implantation of a toggle pin bone anchor and prosthetic ligament was developed for the treatment of traumatic coxofemoral luxation. A cadaver study was performed to assess the viability of the technique. Clinical application in one case is described.

OBJECTIVE To determine the effect of surgical technique and use of a rigid centralizing device on stem positioning and geometric reconstruction in the sagittal plane during total hip replacement in dogs. SAMPLE POPULATION Bilateral femurs from 8 adult mixed-breed canine cadavers. PROCEDURE Femurs were prepared for femoral stem implantation, using 4 variations in technique. Proximal femoral reconstruction and femoral stem positioning were evaluated on radiographs. RESULTS Implants evaluated in this study accurately reconstructed displacement of the femoral head of the intact canine femur in the sagittal plane. Centralization of the distal aspect of the stem was optimized by use of an undersized femoral stem. Ostectomy at the level of the lesser trochanter resulted in the smallest diaphysis-to-implant angle. Anteversion and retroversion of implants significantly decreased the distance between the distal tip of the implant and the adjacent cortex, compared with normoversion. The centralizing device significantly increased the minimum distance between the distal tip of the implant and adjacent cortex but did not improve the odds of actually centralizing the tip of the implant. CONCLUSIONS AND CLINICAL RELEVANCE Malpositioning of implants in the sagittal plane may be minimized through ostectomy at the lesser trochanter and use of an undersized implant positioned in normoversion. Use of a polymethylmethacrylate centralizing device will help eliminate contact between the implant tip and adjacent cortex. Implantation of an undersized femoral component, avoidance of substantial anteversion or retroversion, and use of a rigid centralizing device are recommended when using the prosthesis described-for total hip replacement of dogs.

OBJECTIVE:To determine the outcome of total hip arthroplasty in canine hindlimb amputees.STUDY DESIGN:Retrospective evaluation of clinical cases.METHODS:Data recorded from the medical records of nine dogs included patient signalment, indication for amputation and total hip arthroplasty (THA), interval between amputation and THA, and surgical complications. Radiographs were used to assess implant orientation and evidence of complications. Functional outcome was assessed using direct patient evaluation by one of the authors or primary surgeons, or through telephone interview between the primary author and the owner.RESULTS:Seven dogs ultimately had a good or excellent clinical results. Complications occurred in five dogs. Four dogs luxated the prosthetic joint without an obvious traumatic event within 9 weeks of the initial surgery. Revision surgeries resulted in successful coxofemoral reduction in three of four dogs. There were no clinical or radiographic findings suggestive of implant loosening or infection.CONCLUSION:THA can be a successful salvage procedure in the canine hindlimb amputee with disabling, non-neoplastic, noninfectious coxofemoral disease. The risk of luxation in the early postoperative period is high and revision surgery is required for stabilization.

OBJECTIVESTo test whether femoral ostectomy level, subtrochanteric bone mass removal, and stemsize selection significantly affect stem positioning in canine total hip replacement, and to determine ability of the femoral stem component to restore geometry of the normal femoral head and neck.SAMPLE POPULATIONFemurs from 8 adult mixed-breed canine cadavers.PROCEDUREFemurs were systematically prepared, using 8 combinations of 3 surgical preparation techniques that included level of ostectomy (cervical isthmus vs lesser trochanter), subtrochanteric bone block removal, and femoral stem size (recommended, undersized). Computer-aided analysis of specimen photographs was used to evaluate femoral head offset and position and variability of femoral stem positioning for each of the preparation combinations.RESULTSOriginal femoral head offset and position were reconstructed to within a mean of 0.052 and 0.031 cm, respectively, using an undersized femoral stem after ostectomy at the level of the lesser trochanter. Implantation of an undersized femoral stem after subtrochanteric bone block removal improved ability to centralize the distal tip of the implant and reduce the angle between the femoral diaphyseal and implant axes. Ostectomy at the level of the cervical isthmus tended to force femoral implants into a varus position, and ostectomy at the level of the lesser trochanter tended to force implants into a valgus position.CONCLUSIONSGeometry of normal canine femurs was most closely reconstructed by implantation of an undersized femoral component after ostectomy at the level of the lesser trochanter. Implantation of an undersized femoral component after subtrochanteric bone block removal resulted in the best alignment and centralization of the stem.

OBJECTIVE To document gross and microscopic anatomic features of the collateral ligaments of the canine cubital joint and to determine their structural and material properties. ANIMALS 37 canine cadavers. PROCEDURE After measurement of ligament dimensions, the bone-collateral ligament-bone specimens were loaded in tension until failure, using a materials testing machine. Data from the load-displacement curves were used to determine the structural and material properties of the ligaments. Gross anatomic features were studied during dissection of the specimens from the medial collateral ligament (MCL) and lateral collateral ligament (LCL), which then were saved for microscopic examination. RESULTS Failure load and stiffness values for the LCL were significantly (P < 0.05) greater than those for the MCL. The LCL had obvious cranial and caudal components that attached to the radius and ulna, respectively. The MCL also had cranial and caudal components; however, the cranial component was indistinct, appearing only as a slight thickening of the joint capsule. The caudal component was more prominent; as it extended distad, it had minor attachments to the interosseous and annular ligaments and attached principally on the caudolateral surface of the proximal portion of the radius. The caudal component did not have substantial attachment to the ulna in any of the specimens studied. Both ligaments were composed of closely packed, parallel fascicles of dense collagen, with scant amounts of fibrocartilage and no detectable elastin. CONCLUSIONS Gross anatomic features of the collateral ligaments of the canine cubital joint indicate that they provide principal structural support to the joint; microscopic anatomic features are typical of other ligaments. The LCL is stronger and stiffer than the MCL; however, their material properties are similar. CLINICAL RELEVANCE Knowledge of the sites of attachment of collateral ligament components is essential for surgeons undertaking repair or reconstruction of these structures.

OBJECTIVE To determine whether the nonsteroidal anti-inflammatory drug carprofen directly influences canine chondrocyte metabolism. ANIMALS Cartilage from the femoral heads of 13 dogs undergoing total hip replacement. PROCEDURE Rates of glycosaminoglycan (GAG) synthesis and degradation, protein synthesis, cell viability, and prostaglandin release were determined in canine explant cartilage or monolayer canine chondrocyte cultures in the presence of 0 to 100 micrograms of carprofen/ml. Rate of GAG synthesis was assessed as incorporation of [35S]sulfate into cartilage matrix during a 3-hour pulse label. Degradation of cartilage GAG was assessed as rate of release of [35S]sulfate from prelabeled explant cultures. Rates of total protein synthesis were assessed as incorporation of [35S]methionine into trichloracetic acid precipitable material during a 3-hour pulse label. Radiolabeled chondrocyte proteins were separated by polyacrylamide gel electrophoresis and visualized by fluorography. Rates of prostaglandin E2 release were assessed by radioimmunoassay. RESULTS Carprofen stimulated a significant increase in the rate of GAG synthesis at concentrations of 1 and 10 micrograms/ml, with no change in total protein synthesis, pattern of new protein synthesis, or cell viability. At concentration > or = 20 micrograms/ml, inhibition of GAG synthesis and total protein synthesis was observed. There was no significant change in rate of release of GAG from cartilage explants, but potent inhibition of prostaglandin release was observed. CONCLUSIONS Carprofen has a direct influence on chondrocyte activity, resulting in changes in rate of production of cartilage matrix. CLINICAL RELEVANCE In determining the optimal therapeutic dose of carprofen for arthritic conditions in dogs, it is important to consider potential influences on cartilage, as well as anti-inflammatory actions.

SummaryEight conditioned research dogs, whose body weight was between 25 and 30 kg, had unilateral implantation of a Leeds-Keio (LK) synthetic implant (Dacron polyester) immediately after severance and removal of the cranial cruciate ligament (CCL). A rectangular- shaped autograft, composed of fascia lata, was placed within the LK implant in four of the eight dogs; the other four dogs received the LK implant only. Modified Robert Jones bandages were placed on the limbs that had been operated upon; the bandages were left in place for 48 hours. After that time the limbs were not splinted. The dogs were confined to 1.5 m X 3 m kennels, with twice daily leash walks for the duration of the study. Although the joints that received the LK implants were stable immediately after the operation, they all developed progressive effusion, crepitation and instability accompanied by clinically apparent lameness. All of the dogs were euthanatized three months after the operations. Gross examination of the eight joints that had been operated upon confirmed the presence of degenerative joint disease. Three of the eight dogs had “bucket handle” type tears of their medial meniscus in the joints with the LK implant, and the medial menisci in the other five stifle joints that received LK implants had a fibrillated surface texture. Five of the eight LK implants had either ruptured completely or were stretched and frayed to the point where mechanical testing was not justified. Mean breaking strength of the 3 intact LK implants was 6.6% of the contralateral, control CCL. Ingrowth of fibrous tissue into the LK implants was minimal. The synovium from all joints with LK implants had moderate to severely increased cellularity within the synovial villi and supporting stroma consisting predominantly of lymphocytes, plasma cells and macrophages. Multinucleated giant cells formed aggregates around irregular shaped strands of particulate material which was translucent and refractive. Under polarized light, these particles were bright yellow to green consistent with Dacron particles. It was concluded that the LK implant, as implanted in this study, was not a satisfactory replacement for the CCL in dogs.The Leeds-Keio synthetic replacement for the canine cranial cruciate ligament was implanted in eight dogs. All eight dogs developed progressive instability and secondary degenerative joint disease over a period of three months after the operation. It was concluded that the Leeds-Keio ligament, as implanted in this study, is not satisfactory for use in dogs.

Soft tissue allografts have many uses in orthopaedic surgery, including knee ligament reconstruction, hand tendon surgery, shoulder instability, and rotator cuff reconstruction, The predictable biologic incorporation of soft tissue allografts without rejection or fear of disease transmission continues to be a goal of basic science researchers. a review of the current knowledge of the immune system response to donor specific, nonspecific, and altered tissue antigens in soft tissue or tendon allografts is presented, An in vitro study was done in an attempt to decrease immunogenicity of a frozen bone-ligament graft by adding irrigation with Betadine scrub solution and hydrogen peroxide to the conventional storage process of freezing, Although the irrigation with cytotoxic agents would undoubtedly further decrease immunogenicity, it also decreased stiffness and maximum load by 15%, Whether this decreased strength and stiffness would compromise the incorporation and long term success of soft tissue allografts would need to be studied by in vivo experiments.

Seventy dogs were included in a randomized, controlled, multicenter trial to test the efficacy of carprofen (2.2 mg/kg of body weight, PO, q 12 h) for relief of clinical signs associated with osteoarthritis. Thirty-six dogs received carprofen, and 34 received a placebo. Response of the dogs was evaluated by comparing results of force plate examination and a graded lameness examination performed before and immediately after 2 weeks of treatment, and by obtaining a subjective assessment of the dog's posttreatment condition from owners and participating veterinarians. A physical examination, CBC, serum biochemical analyses, urinalysis, and fecal occult blood test were performed before and after treatment to monitor safety. For force plate evaluation, the odds ratio was 3.3, meaning that a dog treated with carprofen was 3.3 times more likely to have a positive response than was a dog treated with the placebo. For evaluation by a veterinarian, the odds ratio was 3.5, and for owner evaluation, the odds ratio was 4.2. Institution where dogs were treated did not have a significant effect on results. A variety of reactions that may have been related to the medication (placebo or carprofen) were recorded; however, none were considered serious. Serum alanine aminotransferase activity was high in 3 dogs (2 that received placebo and 1 that received carprofen) at the conclusion of treatment; none of the 3 dogs were clinically ill. Ten dogs (5 that received placebo and 5 that received caprofen) had negative pretreatment and positive posttreatment fecal occult blood test results.

Results of total hip arthroplasty in 84 dogs (96 hips) were evaluated. Eight (9.5%) of the 84 dogs developed 1 or more complications after total hip arthroplasty. Complications resolved or were corrected in 4 of the dogs; all 4 ultimately achieved good or excellent hip function. Complications necessitated removal of the prosthesis in the other 4 dogs; 3 ultimately achieved fair hip function and 1 had only poor hip function. Therefore, after resolution of complications, 96% of the hips had good or excellent function. Force plate analysis was performed on 6 dogs with excellent hip function; peak vertical force for the limb that had been operated on was greater than or equal to peak vertical force for the contralateral limb. Radiographically, a radiolucent zone was visible around the acetabular component in 89% of the hips and around the femoral component in 26%. The radiolucent zone around the acetabular and femoral components widened in 14% (6 of 43) and 27% (3 of 11), respectively, of the hips with adequate radiographic follow-up. Aseptic loosening of the acetabular component developed in 3 (3%) of 96 hips; one was successfully revised. Aseptic loosening of the femoral component was not apparent in any of the dogs in this study. Other complications included femoral fracture (n = 3), neurapraxia (3), luxation (1), and unexplained lameness that required implant removal (1). None of the dogs had evidence of wound infection.

SummaryFixation methods for osteochondral shell grafts were studied using replace-ment of a femoral trochlear autograft in rabbits as the model. Twenty skeletally mature rabbits were divided into four groups with five rabbits in each. The articular cartilage of the femoral trochlea, including 2.0 mm of subchondral bone, was removed using a sagittal bone saw. The grafts were immediately reattached using either small Kirschner pins (K-pins), polydioxanone pins (PDP), polydioxanone suture (PDS), or polymethylmethacrylate (PMMA) cement. Six months postoperatively the rabbits were killed and the graft sites compared to the contralateral control using radiography, gross examination, Safranin-O and H & E staining, and sulphate-35 radioactive uptake. Mild degenerative joint changes were evident radio-graphically in all of the operated joints. Articular surface defects at the graft sites were common and included small craters and erosions; a few had larger areas devoid of cartilage. Defects associated with the pin entrance sites were common in the K-pin and PD P groups. The PDS group had the least number of animals with articular surface defects. Safranin-O staining was complete in the PDS group, partial or complete in the K-pin and PD P groups, and partial in all of the joints in the PMM A group. H & E preparations of the cartilage sections were graded from 1 (normal cartilage) to 5 (multiple fissures, severe degradation). The PDS group had a mean (SD) score of 1.8 (0.8), the PD P group 2.4 (1.1), the K-pin group 2.5 (1.3), and the PMM A group 4.6 (0.6). The scores for the PMM A group were significantly greater then the scores for the other groups (p <0.05). The mean (SD) for radioactive counts per minute/mg tissue in treated graft sites as a percent of control was PDS: 130 (83); PDP : 115 (14); K-pins: 92 (42); PMMA : 91 (29). The relative percentages for radioactive uptake were not significantly different (P >0.05). Graft fixation using PDS, PDP, or K-pins was technically easy to perform and the results were generally satisfactory. Fixation using PMM A was technically demanding and histological evidence of moderate to severe cartilage degradation was present in all treated joints.Femoral trochlear autografts in rabbits were used to study fixation methods for osteochondral graft fragments. Six months after the operations the graft sites were evaluated using radiographs, gross examination, Safranin-O and H & E staining, and sulphate-35 radioactive uptake. Grafts stabilized using polydioxanone suture had the least number of articular surface defects and the most complete Safranin-O staining.

The accuracy of diagnoses based on examination of frozen sections was determined by comparing the results to those obtained by examination of tissues prepared using conventional methods (formalin fixation, paraffin-embedded tissue). One hundred ninety-four specimens were examined using the frozen section technique; 37 were examined to confirm a tentative diagnosis or to document lymph node metastasis and the remainder were examined to diagnose an unknown pathologic process. Of the 194 specimens examined, an accurate, specific diagnosis was obtained in 161 (83%); in 19 (10%), the pathologic process was correctly identified, but a specific diagnosis was not obtained; and in 2 (1%) the diagnosis was deferred. The remaining 12 (6%) were incorrectly diagnosed by the frozen section technique. When the number of specimens in which a specific diagnosis was obtained was combined with the number of specimens in which the pathologic process was correctly identified, the overall accuracy rate of the frozen section technique was 93%. There was no difference in the accuracy of the frozen section technique based on the reason for submission of the sample, source of tissue submitted, or the type of pathologic process (i.e., inflammatory or neoplastic). Of the 12 incorrect diagnoses, 4 (33%) were because of sampling errors and 8 (67%) were caused by interpretation errors.(ABSTRACT TRUNCATED AT 250 WORDS)

Unilateral rupture of the cranial cruciate ligament (CCL) was diagnosed in 114 dogs. The affected joint was stabilized surgically in 105 of the 114. Radiographic signs of degenerative joint disease (DJD) were present in the contralateral limb in 29 of 56 dogs at time of diagnosis. Forty-two of the 114 (37%) dogs ruptured their contralateral CCL 17 +/- 13 months after initial diagnosis of unilateral CCL rupture. Seventeen of 29 (59%) that had radiographic evidence of DJD in the contralateral stifle joints ruptured the contralateral CCL 16 +/- 6 months after initial diagnosis. The difference in frequency of contralateral rupture in dogs with radiographically normal contralateral joints with those with DJD in the contralateral joint was significant (p=0.0015, Fisher's exact test.

Data from 10,769 dogs with rupture of the cranial cruciate ligament (CCL) were compared with data from a control population of 591,548 dogs to determine whether age, breed, gender, or body weight was associated with prevalence of CCL rupture. Prevalence of CCL rupture increased as dogs became older, with peak prevalence in dogs 7 to 10 years old. Among breeds represented by > 1,000 individuals, Rottweilers, Newfoundlands, and Staffordshire Terriers had the highest prevalence of CCL rupture, whereas Dachshunds, Basset Hounds, and Old English Sheepdogs had the lowest. Neutered dogs, whether male or female, had a higher prevalence of CCL rupture than did sexually intact dogs. The dog's age at the time of ovariohysterectomy was not associated with prevalence of CCL rupture. Dogs weighing > 22 kg had a higher prevalence of CCL rupture, compared with dogs weighing < 22 kg, and tended to rupture their CCL at a younger age.

Middiaphyseal radial ostectomy was performed in 2 dogs that had premature closure of their distal radial physes. Complications included disuse osteoporosis, carpal hyperextension of the affected and contralateral limbs, degenerative joint disease involving the cubital and carpal joints, synostosis of the radius to the ulna, premature closure of the distal portion of the ulna, and failure to achieve normal limb length. Both dogs were lame after exercise.

Synovial fluid samples from the affected stifle joints of 49 dogs with unilateral rupture of the cranial cruciate ligament (CCL) were analyzed. Thirty-three (67%) had complete rupture and 15 (31%) partial rupture. Mean total protein (3.2 +/- 0.1 g/dl) was slightly elevated (XBAR +/- SEM). Mean nucleated cell count was 1,965 +/- 328 cells/mm3. Nucleated cell counts were < 5,000 cells/mm3 in 92% of the samples. There was no correlation between nucleated cell count and age, body weight, or duration of lameness. Nucleated cell count from dogs with partial CCL ruptures was significantly higher (p < 0.01) compared to samples from dogs with complete ruptures. This data supports the noninflammatory nature of degenerative joint disease secondary to spontaneous CCL rupture. Partial ruptures of the CCL, however, were associated with moderate inflammatory changes in synovial fluid. This suggests that CCL rupture in many dogs may be a progressive process with an inflammatory component in the early stages of ligament and cartilage deterioration.