Caudal cruciate ligament damage in dogs with cranial cruciate ligament rupture

Objective: To investigate the incidence of caudal cruciate ligament (CaCL) damage in dogs with cranial cruciate ligament rupture (CCLR). Study Design: Prospective clinical study. Animals: Dogs (n=24) admitted for surgical stabilization of the stifle after CCLR and 8 healthy dogs with intact cranial cruciate ligament (CCL) and CaCL studied as controls. Methods: Preoperative radiographs and stifle joint images (arthrotomy, 6; arthroscopy, 18) were collected from dogs with CCLR. Severity of arthritis, synovitis, CCL damage, and CaCL damage were assessed using numerical rating scales. The CaCL was probed to determine whether minor fraying or a full thickness defect in the ligament was present. Data collected from the study population were compared with the control population of dogs. Results: The CaCL was damaged in 21/24 (88%) of dogs with CCLR; 6/24 (25%) had a full thickness defect in the CaCL. Severity of stifle synovitis and severity of damage to the CaCL were positively correlated (P<.05). Conclusions: The CaCL is damaged in a high percentage of dogs with CCLR. A significant and positive correlation exists between the degree of synovitis present and the extent of CaCL damage. Clinical Relevance: In dogs with CCLR, cruciate ligament pathology typically involves both the CCL and CaCL. As the severity of synovitis and the extent of CaCL damage are related, this observation supports the hypothesis that stifle synovitis may contribute to CCL and CaCL degeneration and subsequent damage.     

Perioperative administration of antimicrobials associated with elective surgery for cranial cruciate ligament rupture in dogs: 83 cases (2003-2005)

OBJECTIVE: To evaluate perioperative antimicrobial use associated with elective surgery for cranial cruciate ligament rupture in dogs. DESIGN: Retrospective case series. ANIMALS: 83 dogs. PROCEDURES: Medical records were reviewed and antimicrobial use practices were evaluated for dogs with no other problems that would affect antimicrobial use decisions. RESULTS: Antimicrobials were administered before or during surgery to 75 of 83 (90%) dogs. Timing of administration with respect to first incision, intraoperative administration, and duration of administration were variable. Antimicrobial administration began after surgery in 3 (3.6%) dogs. Fifty-five of 65 (85%) dogs treated before surgery received the first dose within 60 minutes of the first incision. Time from first antimicrobial administration to closure of the incision ranged from 15 to 285 minutes (mean +/- SD, 141 +/- 53 minutes). If a guideline of repeated administration every 2 hours after first administration until closure of the surgical site was used, 22 of 43 (51%) dogs received the required intraoperative dose, whereas 6 of 32 (19%) dogs that did not require intraoperative treatment were treated. Twenty-four (29%) dogs received antimicrobials after surgery. CONCLUSIONS AND CLINICAL RELEVANCE: Certain discrepancies between antimicrobial use practices in this study and standard guidelines used in human medicine were evident.     

Prevalence of and risk factors for hip dysplasia and cranial cruciate ligament deficiency in dogs

OBJECTIVE-To evaluate prevalence of and risk factors for hip dysplasia (HD) and cranial cruciate ligament deficiency (CCLD) in dogs and determine change in prevalence over time. DESIGN-Cross-sectional study. ANIMALS-1,243,681 Dogs for which information was reported to the Veterinary Medical Database between 1964 and 2003. PROCEDURES-Information on breed, sex, and age was collected, and prevalences and odds ratios were calculated. RESULTS-Castrated male dogs were significantly more likely than other dogs to have HD (odds ratio [OR], 1.21), and castrated male (OR, 1.68) and spayed female (OR, 2.35) dogs were significantly more likely to have CCLD. Dogs up to 4 years old were significantly more likely to have HD (OR for dogs 2 months to 1 year old, 1.22; OR for dogs > 1 to 4 years old, 1.48), whereas dogs > 4 years old were significantly more likely to have CCLD (OR for dogs > 4 to 7 years old, 1.82; OR for dogs > 7 years old, 1.48). In general, large- and giant-breed dogs were more likely than other dogs to have HD, CCLD, or both. Prevalences of HD and CCLD increased significantly over the 4 decades for which data were examined. CONCLUSIONS AND CLINICAL RELEVANCE-Results suggested that sex, age, and breed were risk factors for HD, CCLD, or both in dogs and that prevalences of HD and CCLD have increased over time.     

Partial rupture of the cranial cruciate ligament of the stifle in dogs: 25 cases (1982-1988)

Partial rupture of the cranial cruciate ligament was diagnosed in 25 dogs. In all dogs, the primary problem at the time of physical examination was hind limb lameness. The mean time from initial onset of lameness to diagnosis at exploratory surgery was 17 weeks. A cranial drawer sign was detected in 13 of the 25 dogs; in 9, the cranial drawer sign was evident only when the stifle was positioned in flexion. Of the 25 dogs, 12 had no detectable cranial drawer sign in response to manipulation of the involved stifle. In all dogs, lateral stifle arthrotomy was performed in routine manner, and the cranial cruciate ligament was found to be incompletely torn. Lesions identified during arthrotomy were rupture of the craniomedial band (n = 20 dogs), interstitial tear (n = 4 dogs), and rupture of the caudolateral band (n = 1 dog).     

Partial rupture of the cranial cruciate ligament in dogs

Four cases of partial rupture of the craniomedial part of the cranial cruciate ligament (CCL) are presented. Clinical examination revealed only subtle signs of CCL injury. The cranial drawer sign was present in two dogs and in flexion only. As the cranial drawer sign is not always evident a tentative diagnosis of partial CCL rupture should be based on history, joint tenderness and joint effusion. Arthrotomy and careful probing of the ligament is indicated. In these cases the lesion was treated immediately after diagnosis to prevent further degeneration and possible total rupture of the ligament. A fascial graft using the ‘over the top’ reconstruction technique was performed leaving the intact portion of the ligament in situ. Follow-up examination after four to six months revealed normal limb function in three dogs whereas slight and periodic lameness persisted in one dog.     

Immunopathological mechanisms in dogs with rupture of the cranial cruciate ligament

The majority of studies on cranial cruciate ligament (CrCL) disease to date have been carried out on dogs that already sustained a CrCL rupture, which is the end-stage of the disease. Investigations have recently been carried out to study humoral and cellular immunopathological mechanisms in predisposed dogs before clinical rupture of the contralateral CrCL. The cruciate ligaments are mainly composed of collagen type I, and immune responses to collagen have been suggested as a cause of CrCL degradation in dogs. None of these investigations showed evidence that anticollagen type I antibodies alone initiate CrCL damage. However, in predisposed dogs a distinct anticollagen type I antibody gradient was found towards the contralateral stifle joint that eventually sustained a CrCL rupture, suggesting that there was an inflammatory process present in these joints before detectable joint instability occurred. The importance of cellular reactivity to collagen type I in cruciate disease also remains unclear. Peripheral blood mononuclear cell proliferation to collagen type I was very diverse in dogs with cruciate disease whereas some sham operated dogs and healthy dogs tested positive as well. It is not yet determined whether cellular reactivity to collagen type I exists locally in the stifle joints nor whether this could initiate CrCL degradation. Inflammatory processes within the stifle joint can alter the composition of the cruciate ligaments. In animal models of immune-mediated synovitis, the mechanical strength of the CrCL is significantly reduced. Immunohistochemical studies on synovial tissues from dogs with rheumatoid arthritis and dogs with cruciate disease revealed that the pathologic features are similar in both joint pathologies and that the differences are mainly quantitative. Joint inflammation induced by biochemical factors such as cytokines has been implied in CrCL degeneration. In several studies, the levels of pro-inflammatory and T helper cytokines were measured in dogs that sustained a CrCL rupture, but the exact role of the various cytokines in the pathogenesis of CrCL disease remains inconclusive. More recently, the levels of the cytokines have been investigated over time in predisposed dogs before and after CrCL rupture. IL-8 expression tended to be higher in stifle joints that will rupture their CrCL during the next 6 months than in those that will not, indicating an inflammatory process in these joints before clinical rupture. This review provides a comprehensive overview of all possible implications of humoral and cell-mediated immune responses published in dogs with cruciate disease together with publications from human joint diseases. Furthermore, this review highlights recent findings on cytokines and proteinases in the accompanying joint inflammation.     

Comparison of tibial plateau angles in dogs with unilateral versus bilateral cranial cruciate ligament rupture: 150 cases (2000-2006)

OBJECTIVE: To compare tibial plateau angle (TPA) in dogs with unilateral versus bilateral cranial cruciate ligament (CCL) rupture, to compare right versus left TPA in dogs with bilateral CCL rupture, and to determine whether TPA can be used to predict whether a dog with unilateral CCL rupture would subsequently rupture the contralateral CCL. DESIGN: Retrospective case series. ANIMALS: 150 dogs with unilateral (n=58) or bilateral (92) CCL rupture. PROCEDURES: Medical records were reviewed and TPA was recorded. Dogs with unilateral CCL rupture that were not known to have ruptured the contralateral ligament were followed up for a minimum of 2 years. RESULTS: Dogs with unilateral CCL rupture were significantly older (median, 7.0 years) than dogs with bilateral CCL rupture (median, 4.5 years). Median TPA for dogs with unilateral CCL rupture (26 degrees) was not significantly different from median TPA for dogs with bilateral rupture (27 degrees in both the right and left limbs), and right and left TPAs were not significantly different in dogs with bilateral CCL rupture. There was no correlation between TPA and the time interval between diagnosis of the initial and subsequent CCL ruptures in dogs with bilateral CCL rupture. CONCLUSION AND CLINICAL RELEVANCE: Results suggested that TPA in the range studied (mostly<35 degrees) was not a useful predictor of contralateral CCL rupture among dogs with unilateral CCL rupture, although age may be a risk factor for development of bilateral CCL rupture. The incidence of bilateral CCL rupture may be higher than previously reported.     

Arthroscopic evaluation of menisci in dogs with cranial cruciate ligament injuries: 100 cases (1999-2000)

OBJECTIVE: To determine prevalence of meniscal injuries by use of arthroscopic examination in dogs with cranial cruciate ligament (CCL) injuries. DESIGN: Retrospective study. ANIMALS: 94 dogs with 100 injured CCLs. PROCEDURE: Records for 94 large dogs (> 20 kg [44 lb]) with 100 naturally occurring CCL injuries that were examined arthroscopically were reviewed. Pathologic findings in the CCL (complete or partial tears), prevalence and type of meniscal injuries, and periarticular osteophytes were recorded. RESULTS: 77% of joints had tears of the lateral meniscus; most were a series of small radial tears of the cranial horn. Fifty-eight percent of joints had tears of the medial meniscus. Positive correlation between complete tears of the CCL and medial meniscal damage was found. No significant relationships were detected between periarticular osteophyte formation and meniscal injury, medial and lateral meniscal injury, or degree of CCL tear and lateral meniscal injury. CONCLUSIONS AND CLINICAL RELEVANCE: There is a strong association between CCL injury and lateral and medial meniscal injuries in dogs. Clinical importance of lateral meniscal lesions is not known; a much higher percentage of dogs had such injuries than has been reported previously, possibly because of use of arthroscopy.     

Apoptosis of ligamentous cells of the cranial cruciate ligament from stable stifle joints of dogs with partial cranial cruciate ligament rupture

OBJECTIVE: To describe the presence and amount of apoptotic ligamentous cells in different areas of partially ruptured canine cranial cruciate ligaments (prCCLs) and to compare these findings with apoptosis of ligamentous cells in totally ruptured cranial cruciate ligaments (trCCLs). ANIMALS: 20 dogs with prCCLs and 14 dogs with trCCLs. PROCEDURES: Dogs with prCCLs or trCCLs were admitted to the veterinary hospital for stifle joint treatment. Biopsy specimens of the intact area of prCCLs (group A) and the ruptured area of prCCLs (group B) as well as specimens from trCCLs (group C) were harvested during arthroscopy. Caspase-3 and poly (ADP-ribose) polymerase (PARP) detection were used to detect apoptotic ligamentous cells by immunohistochemistry. RESULTS: No difference was found in the degree of synovitis or osteophytosis between prCCLs and trCCLs. No difference was found in degenerative changes in ligaments between groups A and B. A substantial amount of apoptotic cells could be found in > 90% of all stained slides. A correlation (r(s) = 0.71) was found between the number of caspase-3-and PARP-positive cells. No significant difference was found in the amount of apoptotic cells among the 3 groups. No significant correlation could be detected between the degree of synovitis and apoptotic cells or osteophyte production and apoptotic cells. CONCLUSIONS AND CLINICAL RELEVANCE: The lack of difference between the 3 groups indicates that apoptosis could be a factor in the internal disease process leading to CCL rupture and is not primarily a consequence of the acute rupture of the ligament.     

Progression of radiographic evidence of osteoarthritis following tibial plateau leveling osteotomy in dogs with cranial cruciate ligament rupture: 295 cases (2001-2005)

OBJECTIVE: To determine whether radiographic signs of osteoarthritis became progressively worse and tibial slope angle (TSA) changed substantially following tibial plateau leveling osteotomy for treatment of cranial cruciate ligament rupture in dogs. DESIGN: Retrospective case series. ANIMALS: 295 dogs (373 stifle joints). PROCEDURES: Medical records were reviewed. Radiographs obtained before and 8 weeks after surgery were used to determine the degenerative joint disease (DJD) score, calculated as the sum of individual scores (0 through 3) assigned to 30 radiographic factors. Radiographs obtained immediately and 8 weeks after surgery were used to measureTSA. For dogs that underwent bilateral surgery, data for the first joint treated were used in analyses. Data for the second joint treated in dogs that underwent bilateral surgery were analyzed separately. RESULTS: A small, but significant, increase was found in mean DJD score 8 weeks after surgery, compared with mean preoperative score. An inverse relationship was found between preoperative DJD score and the difference between postoperative and preoperative DJD scores. Mean TSA 8 weeks after surgery was significantly higher than mean TSA immediately after surgery. Analysis of data for the second stifle joints in the 78 dogs that underwent bilateral surgery yielded similar results. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggested that there was a small, but measurable, increase in the severity of radiographic changes attributed to osteoarthritis in the stifle joints of dogs that underwent tibial plateau leveling osteotomy because of cranial cruciate ligament rupture.     

Clinical assessments of increased sensory sensitivity in dogs with cranial cruciate ligament rupture

Dogs with chronic pain have a compromised quality of life. Repeatable and accurate sensory assessments form a means by which the hypersensitivity likely to reflect chronic pain may be quantified. These assessments can be applied to individuals to identify those that may benefit from improved analgesic relief. In this study four sensory assessments were evaluated in dogs presenting with a naturally occurring chronic painful condition (cranial cruciate ligament rupture, CCLR) and were compared with healthy control animals of similar age and weight. Inter-digital von Frey filament and thermal sensitivity tests revealed that the affected hind limb of dogs with CCLR was significantly more sensitive than the opposing limb. Static weight bearing and gait parameter scores were also reduced in the affected hind limb compared to the opposing hind limb of dogs with CCLR; no such differences were found between the hind limbs of healthy (control) dogs. The quantitative sensory tests permitted the differentiation of limbs affected by CCLR from healthy limbs. Dogs presenting with CCLR demonstrate objectively quantitative sensory sensitivities, which may require additional consideration in case management.     

Synovitis in dogs with stable stifle joints and incipient cranial cruciate ligament rupture: a cross-sectional study

Objective: To evaluate stifle joints of dogs for synovitis, before development of joint instability and cranial cruciate ligament rupture (CrCLR). Study Design: Cross‐sectional study. Animals: Dogs (n=16) with CrCLR and stable contralateral stifles; 10 control dogs with intact CrCL. Methods: Arthritis and tibial translation were graded radiographically. Synovitis severity and cruciate pathology were assessed arthroscopically. Presence of inflammatory cells in synovial membrane biopsies was scored histologically. CrCLR stifle pairs and control stifles were compared. Results: Radiographic evidence of arthritis, cranial tibial translation, and arthroscopic synovitis were increased in unstable stifles, when compared with stable contralateral stifles in CrCLR dogs (P<.05). Arthroscopic synovitis in both joints of CrCLR dogs was increased compared with controls, was correlated with radiographic arthritis (S_R=0.71, P<.05), and was present in all stable contralateral stifles. Arthroscopically, 75% of stable stifle joints had CrCL fiber disruption, which correlated with severity of synovitis (S_R=0.56, P<.05). Histologic evidence of synovitis was identified in all CrCLR dogs, but was only significantly correlated with arthroscopic observations in stable stifles (r²=0.57, P<.005). Conclusion: Synovitis is an early feature of the CrCLR arthropathy in dogs before development of joint instability clinically. Severity of synovitis is correlated with radiographic arthritis in joints with minimal to no clinically detectable CrCL damage.     

Nitric oxide metabolite production in the cranial cruciate ligament, synovial membrane, and articular cartilage of dogs with cranial cruciate ligament rupture

OBJECTIVE: To measure concentrations of nitric oxide metabolites (nitrite-nitrate [NOt]) in cartilage, synovial membrane, and cranial cruciate ligament (CCL) in dogs and evaluate associations with osteoarthritis in dogs with CCL rupture. ANIMALS: 46 dogs with CCL rupture and 54 control dogs without joint disease. PROCEDURE: Tissue specimens for histologic examination and explant culture were harvested during surgery in the CCL group or immediately after euthanasia in the control group; NOt concentrations were measured in supernatant of explant cultures and compared among dogs with various degrees of osteoarthritis and between dogs with and without CCL rupture. RESULTS: Osteoarthritic cartilage had significantly higher NOt concentration (1,171.6 nmol/g) than did healthy cartilage (491.0 nmol/g); NOt concentration was associated with severity of macroscopic and microscopic lesions. Synovial membrane NOt concentration did not differ between dogs with and without CCL rupture. Ruptured CCL produced less NOt than did intact ligaments. In control dogs, NOt concentrations were similar for intact ligaments (568.1 nmol/g) and articular cartilage (491.0 nmol/g). Synthesis of NOt was inhibited substantially by coincubation with inhibitors. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggest that NOt in canine joint tissues originates from the inducible nitric oxide synthase pathway. Nitric oxide metabolite production in cartilage was greater in dogs with osteoarthritis than in healthy dogs and was associated with lesion severity, suggesting that nitric oxide inhibitors may be considered as a treatment for osteoarthritis. The CCL produces substantial concentrations of NOt; the importance of this finding is unknown.