Effect of Four Antimicrobial Lavage Solutions on the Tarsocrural Joint of Horses

Three concentrations of povidone-iodine (0.1% w/v, 0.2% w/v, 0.5% w/v) and one concentration of chlorhexidine (0.5% w/v) were selected as antimicrobial joint lavage solutions. Through-and-through joint lavage was performed with one of these antimicrobial solutions on a tarsocrural joint of 12 horses. The contralateral tarsocrural joints (control limbs) were lavaged with a balanced electrolyte solution (BES). The effect of the lavage solution on the joints was evaluated with respect to lameness, foot flight pattern, soreness to joint palpation, articular and periarticular enlargement, and synovial fluid composition on Day 1,4, and 8 postlavage. On Day 8 postlavage, all horses were euthanized and the tarsocrural joints were examined.
All solutions induced a synovitis. Based on clinical assessment, synovial fluid protein levels, color, clarity, mucin clot forming ability, gross appearance of the joint at necropsy, and synovial membrane histologic evaluation, a similar, mild, transient, synovitis was induced by the BES and 0.1% povidone-iodine (PI) solution. The 0.2% PI solution induced a more prolonged neutrophilic response and poorer mucin clot forming ability in the synovial fluid as compared to the BES.
The 0.5% PI and 0.5% chlorhexidine solutions produced severe lameness, soreness to joint palpation, and limb enlargement. The elevated synovial fluid total protein content persisted significantly longer (p < 0.05) than the corresponding control (BES) solution. Histologic evaluation of the synovial membrane confirmed the presence of a moderate to severe neutrophilic synovitis in these treatment groups.     

Povidone-iodine lavage treatment of experimentally induced equine infectious arthritis

Both tarsocrural joints of 4 horses were inoculated with 1.5 X 10(5) colony-forming units of Staphylococcus aureus. On days 1, 3, and 6, each horse had one tarsocrural joint lavaged with a balanced electrolyte solution and had the contralateral tarsocrural joint lavaged with 0.1% povidone-iodine solution. All horses were orally administered trimethoprim (5 mg/kg)/sufadiazine (25 mg/kg) combination twice daily and phenylbutazone (2 g) once daily for the duration of the study (21 days). On days 0, 1, 3, 6, 9, 14, and 21, synovial fluid specimens were collected and analyzed for color, clarity, total protein concentration, WBC count and differential, and mucin clot-forming ability. Synovial fluid specimens collected on days 1, 3, 6, 9, 14, and 21 were bacteriologically cultured. On day 21, all horses were euthanatized, the tarsocrural joints were opened and examined, synovial membrane specimens were collected, bacteriologically cultured, and histologically evaluated, and articular cartilage specimens were histochemically evaluated. Repeated measures analysis of variance were used to evaluate differences between lavage solutions and among days for objective measurements. A paired t test was used to evaluate differences between solutions for the indices of synovial membrane inflammation and articular cartilage staining intensity with safranin-O-fast green. To be considered significant, the probability of a type-I error was less than 0.05. Significant differences were not found between joints lavaged with electrolyte solution vs povidone-iodine solution for synovial total protein concentration, WBC count, results of synovial fluid and membrane bacteriologic culture, synovial membrane inflammation, or articular cartilage glycosaminoglycan concentration.(ABSTRACT TRUNCATED AT 250 WORDS)     

Synovial Fluid and Clinical Changes After Arthroscopic Partial Synovectomy of the Equine Middle Carpal Joint

Changes in synovial fluid and clinical variables after arthroscopic partial synovectomy of the middle carpal joint were studied in 12 normal horses. A 7 mm motorized synovial resector was inserted into each middle carpal joint; one middle carpal joint of each horse was randomly selected to have arthroscopic synovectomy (treated) and the opposite joint was lavaged (control). Lameness examinations and synovial fluid analyses were performed before operation and at 8, 14, 21, and 28 days after operation. Lameness variables did not differ between treated and control legs. Middle carpal and carpometacarpal joint circumference measurements were increased for 4 weeks. Synovial fluid specific gravity, pH, total protein, albumin concentration, and alpha-1-, beta- and gamma-globulin concentrations, at 8 and 14 days were significantly higher than before operation in both treated and control middle carpal joints. No significant differences were found between treated and control middle carpal joints at any time for color, clarity, pH, mucin clot formation, total protein, albumin, and globulin fractions. Arthroscopic partial synovectomy and lavage did not cause significant lameness and resulted in a synovitis indistinguishable from synovitis related to arthroscopic lavage alone.     

Ex vivo investigation of the use of hydrothermal energy to induce chondrocyte necrosis in articular cartilage of the metacarpophalangeal and metatarsophalangeal joints of horses

OBJECTIVE: To evaluate the use of hydrothermal ablation of articular cartilage for arthrodesis in horses through investigation of the effects of joint lavage with physiologic saline (0.9% NaCI) solution (80 degrees C) for various treatment times on chondrocyte viability in the articular cartilage of the metacarpophalangeal and metatarsophalangeal joints of cadaveric horse limbs. Sample Population-7 pairs of metacarpophalangeal and 8 pairs of metatarsophalangeal joints from 8 Thoroughbreds. PROCEDURE: The horses were euthanatized for reasons unrelated to musculoskeletal disease. On a random basis, 1 joint of each pair underwent intra-articular lavage for 5, 10, or 15 minutes with heated saline solution (80 degrees C); the other joint underwent sham treatment of similar duration with saline solution at 22 degrees C (control). Cartilage samples from the distal articular surface of metacarpus III (or metatarsus III), the proximal surface of the proximal phalanx, and the lateral and medial proximal sesamoid bones were assessed for chondrocyte viability via confocal microscopy and viability staining following enzymatic digestion. RESULTS: Compared with the control joints, findings of both viability assays indicated that the percentage of sites containing viable chondrocytes in heat-treated joints was decreased.Treatment hazard ratios of 0.048 (confocal microscopy) and 0.2 (digestion assay) were estimated. Histologically, periarticular soft tissues had minimal detrimental effects after heat treatment. CONCLUSIONS AND CLINICAL RELEVANCE: Ex vivo intra-articular lavage with saline solution at 80 degrees C resulted in the death of almost all articular chondrocytes in the joint. This technique may be a satisfactory method for extensive cartilage ablation when performing arthrodesis by minimally invasive techniques.     

Morphological Effects of Arthroscopic Partial Synovectomy in Horses

Gross and microscopic effects of arthroscopic partial synovectomy on synovium and articular cartilage of middle carpal joints were studied in 15 horses. A 7-mm diameter motorized synovial resector was inserted into each middle carpal joint and arthroscopic partial synovectomy and lavage or arthroscopic lavage alone was performed. Study periods were 0 (three horses), 16 (three horses), and 30 days (six horses). No gross evidence of degenerative joint disease was observed at day 16 or 30. At 30 days, resected areas lacked villi and there was deposition of fibrin on the synovial surface with varying amounts of newly formed fibrovascular tissue. Thirty days after arthroscopic synovectomy, normal synovium had not formed in equine middle carpal joints.     

Evaluation of use of dimethyl sulfoxide for intra-articular lavage in clinically normal horses

The antebrachiocarpal and tarsocrural joints of 10 adult horses were randomly assigned to 1 of 4 groups. Groups were formulated and were treated as follows: group 1, control (arthrocentesis only); group 2, buffered lactated Ringer solution; group 3, 10% dimethyl sulfoxide (DMSO; w/v) in lactated Ringer solution; and group 4, 30% DMSO (w/v) in lactated Ringer solution. Joints were lavaged once with the respective solution. Prior to lavage and on days 1, 4, and 8 after lavage, all horses were evaluated for lameness and joint effusion; synovial fluid total and differential WBC counts, synovial fluid total protein concentration, and mucin clot quality were determined. Horses were euthanatized on day 8, and joints were evaluated grossly, histologically, and histochemically. Significant difference was not observed in effect of lactated Ringer solution, 10% DMSO, and 30% DMSO on any measured variable. At 24 hours after treatment, significant (P less than 0.05) difference in synovial fluid WBC numbers and total protein concentration was detected between control and treated joints. Eighty percent of lavaged joints had effusion 24 hours after treatment, compared with 30% of control joints. Gross, histopathologic, or histochemical differences were not detected between treated and control joints. Results of the study indicate that buffered lactated Ringer, 10% DMSO, and 30% DMSO solutions induce similar inflammatory changes in articular structures and significantly greater inflammatory reaction than does arthrocentesis alone.     

Effects of intra-articular administration of dimethylsulfoxide on chemically induced synovitis in immature horses

The effects of intra-articular administration of dimethylsulfoxide (DMSO) on chemically induced synovitis in the middle carpal joint of 6 weanling horses were evaluated. Following aseptic collection of synovial fluid, the middle carpal joint of each forelimb was injected with 50 mg of Na-monoiodoacetate to induce synovitis. Eight days after injection, synovial fluid was obtained and the right middle carpal joints were injected with 2 ml of 40% DMSO in lactated Ringer solution. The corresponding joints of the left limb (control) were injected with 2 ml of lactated Ringer solution. Sampling and treatments were repeated on post-injection days 11 and 14, for a total of 3 treatments. Horses were visually evaluated daily for lameness and joint effusion. Synovial fluid was evaluated for color and clarity, differential and total WBC count, total protein content, and hyaluronic acid concentration. The Kaegi gait analysis system provided an objective assessment of lameness prior to inducing synovitis, again on day 7, and on day 17. At necropsy (day 17), synovial fluid, synovial membrane, and articular cartilage specimens were collected. Joint effusion was evident 12 hours after injection of Na-monoiodoacetate in all joints. Mild lameness was evident at 24 hours; however, the lameness resolved by 72 hours. Objective assessment of lameness did not reveal significant differences between treatment or control limbs. Hyaluronic acid concentrations increased significantly (P = 0.023) above baseline values in most joints over the study period. Synovial fluid WBC counts increased significantly (P = 0.002) following Na-monoiodoacetate injection and remained significantly (P = 0.002) above baseline values throughout the study.(ABSTRACT TRUNCATED AT 250 WORDS)     

Brachygnathia superior and degenerative joint disease: a new lethal syndrome in Angus calves

Brachygnathia superior and generalized diarthrodial degenerative joint disease were seen in 17 related, purebred Angus calves ranging in age from 2 days to 4 months. Craniometrical studies revealed decreased maxillary and palatine bone lengths and increased cranial, skull, and facial indices. Radiological evaluation of major appendicular joints demonstrated lipping of the joint margins with osteophyte formation, sclerosis of subchondral bone, and narrowing of joint spaces. Synovial fluid evaluation indicated joint degeneration but no etiologic agent. Rheumatoid factor analysis of plasma was negative. Grossly, all major appendicular joints were defective including the atlanto-occipital articulation. Lesions ranged from loss of surface luster to erosions and deep ulcers with eburnation of the subchondral bone and secondary proliferative synovitis. Histological changes were degeneration of the articular cartilage matrix, chondrocyte necrosis, flaking and fibrillation, chondrone formation, erosions and ulcers of the articular cartilage with subchondral bone sclerosis, vascular invasion with fibrosis, and chronic, nonsuppurative, proliferative synovitis. Growth plates had defective chondrocyte proliferation and hypertrophy with aberrant ossification of calcified cartilaginous matrix. Histochemical analysis of cartilage and bone failed to incriminate which component was defective, glycosaminoglycan or collagen, but indicated different distribution or absence of one or the other. Genealogic studies revealed a genetic basis for the new defect.     

Effects of 0.05% Chlorhexidine Lavage on the Tarsocrural Joints of Horses

In six horses, a 0.05% solution of chlorhexidine diacetate was used to lavage one tarsocrural joint; the contralateral control joint was lavaged with lactated Ringer's solution. Horses were evaluated daily for lameness. Synovial fluid samples were collected on days 1, 4, and 8 for determination of protein concentration, total and differential leukocyte counts, and mucin clot formation. After death on day 8, synovium and osteochondral samples were collected from the tarsocrural joints for examination of morphology and proteoglycan staining. Lavage with chlorhexidine solution caused lameness that was reduced but still evident at day 8. Synovial protein concentration was significantly increased by chlorhexidine lavage; the greatest increase occurred on day 1. Joint lavage increased synovial leukocyte counts on day 1, primarily by increasing polymorphonuclear (PMN) cell counts. Although total synovial leukocyte counts returned to normal by day 4, PMN cell counts remained elevated through day 8; PMN cell counts for chlorhexidine-lavaged joints were typically twice that of control joints. Chlorhexidine lavage caused synovial ulceration, inflammation, and abundant fibrin accumulation. Consistent differences in proteoglycan staining were not detected between control and chlorhexidine-lavaged joints. Joint lavage with 0.05% chlorhexidine diacetate, the lowest known bactericidal concentration, is not recommended for equine joints.     

Repair and Function of Synovium After Arthroscopic Synovectomy of the Dorsal Compartment of the Equine Antebrachiocarpal Joint

The reparative ability of equine synovium was determined by gross, histological, and ultrastructural examination. The functional potential of the synovium was estimated by examination of synovial cell organelles with transmission electron microscopy. Results from rested and exercised horses were compared to determine the effect of exercise on synovial healing. The response of the synovectomized joint to exercise was evaluated with a standardized lameness examination and by gross, histological, and histochemical observations of the articular cartilage. A 7-mm diameter motorized synovial resector was used to perform a subtotal synovectomy in 1 antebrachiocarpal joint of each of 8 horses; the contralateral joint served as a control. After 2 months rest, four randomly selected horses were rigorously exercised for the remainder of the study; the other four horses continued paddock rest. Lameness examinations and synovial fluid analyses were conducted at 0, 2, 30, 60, and 120 days. Synovium and articular cartilage from all horses were examined at necropsy at 120 days. None of the horses were lame during the study, and a transient synovitis occurred in the synovectomized joints. The hyaluronan concentration of treated joints decreased at 2 days but returned to normal by 60 days. Synovial fluid composition, including hyaluronan concentration, was unchanged by exercise. Significant cartilage damage was not observed in any of the joints. At 120 days, the healing synovium was devoid of villi and its subintima was fibrotic, however transmission electron microscopy confirmed that an intimal layer was present within the repair tissue. The cells within the repair tissue appeared actively engaged in both synthesis and phagocytosis. Exercise did not modify any of these findings. The results of this study suggest that 120 days after subtotal synovectomy, the joint environment was maintained and the resected synovium had evidence of restoration and increased metabolic potential. Synovectomized joints withstood exercise but synovial repair was not accelerated by exercise.     

Cartilage-derived retinoic acid-sensitive protein in equine synovial fluid from healthy and diseased joints

Reasons for performing study: More sensitive and specific diagnostic methods for early detection of changes in the joint cartilage are needed. Cartilage‐derived retinoic acid‐sensitive protein (CD‐RAP) is a potential marker of cartilage synthesis and regeneration. This is the first study on equine CD‐RAP. Objectives: To evaluate the ability of a commercially available human sandwich ELISA assay to detect equine CD‐RAP in synovial fluid from healthy and diseased joints. Methods: Synovial fluid was collected from 28 horses with no signs of joint disease and from 5 with induced inflammatory arthritis. CD‐RAP concentrations were measured using a human CD‐RAP ELISA. Intra‐ and interassay imprecision of the assay were evaluated by multiple measurements on pools of equine synovial fluid. Assay inaccuracy was determined by linearity under dilution. Results: The assay showed moderate to large intra‐ and interassay variation when applied to equine synovial fluid. Equine CD‐RAP was detected in synovial fluid from healthy horses ranged at 8.2–52 ng/ml. Repeated arthrocentesis (after injection of isotonic saline), age, joint or gender did not significantly affect CD‐RAP concentrations. Twelve hours after intra‐articular injection of lipopolysaccharide, concentrations of CD‐RAP were significantly lower than after injection of isotonic saline and remained significantly lower until the end of the study at 144 h. Conclusion and potential relevance: The assay is suitable for longitudinal monitoring of CD‐RAP concentration in individual horses. Disease significantly influenced CD‐RAP levels. Similar to previous results obtained in man, CD‐RAP seems to be a marker of cartilage synthesis and/or regeneration in horses.     

The effects of heated and room-temperature abdominal lavage solutions on core body temperature in dogs undergoing celiotomy

To document the magnitude of temperature elevation obtained with heated lavage solutions during abdominal lavage, 18 dogs were lavaged with sterile isotonic saline intraoperatively (i.e., during a celiotomy). In nine dogs, room-temperature saline was used. In the remaining nine dogs, saline heated to 43+/-2 degrees C (110+/-4 degrees F) was used. Esophageal, rectal, and tympanic temperatures were recorded every 60 seconds for 15 minutes after initiation of the lavage. Temperature levels decreased in dogs lavaged with room-temperature saline. Temperature levels increased significantly in dogs lavaged with heated saline after 2 to 6 minutes of lavage, and temperatures continued to increase throughout the 15-minute lavage period.     

An evaluation of nonsuppurative joint disease in slaughter pigs

Fifty-two joints from pigs with nonsuppurative joint disease from a local abattoir were examined grossly, histologically, and microbiologically in order to establish macroscopic differences between degenerative arthropathy and arthritis due to an infectious organism. The joints were grouped grossly according to the type and severity of lesions of the synovial membrane and cartilage, and microscopically according to the severity of synovial membrane lesions. Osteochondrosis and Erysipelothrix rhusiopathiae were the most common causes of nonsuppurative joint disease in the joints examined. The major macroscopic differences between these two arthropathies were in the nature and severity of the synovial and cartilaginous lesions and involvement of the lymph node draining the diseased joint. Typically, in osteochondrosis, the changes are feathery hypertrophy of villi, focal full-thickness cartilage buckles, ulcers or flaps, and no change in the draining lymph node, whereas in Erysipelothrix- caused arthritis, the villous hypertrophy is severe and polypoid in nature, there is diffuse erosion of articular cartilage, and the draining lymph node is consistently hypertrophic and often cystic.     

The effect of implanting gentamicin-impregnated polymethylmethacrylate beads in the tarsocrural joint of the horse

OBJECTIVE: To determine the effect of intra-articular gentamicin-impregnated polymethylmethacrylate (PMMA) beads inserted in the equine tarsocrural joint on the synovial fluid, synovial lining, and cartilage, and to determine the peak and sustainable gentamicin concentrations in synovial fluid and plasma. STUDY DESIGN: Pharmacokinetic, cytologic, and histologic study of the effect of gentamicin-impregnated PMMA on normal equine tarsocrural joints. ANIMALS: Five healthy adult horses. METHODS: Gentamicin-impregnated PMMA bead strands (3 strands each of 40 beads, with each strand containing 100 mg gentamicin) were surgically inserted into one radiographically normal tarsocrural joint in 5 horses. Each horse had both joints flushed with 1 L of lactated Ringer's solution before bead administration. Synovial fluid total protein concentration, white blood cell (WBC) count, gentamicin concentration, synovial histology, cartilage integrity, and cartilage glycosaminoglycan (GAG) concentrations were determined. RESULTS: Gentamicin concentration (mean +/- SEM peak concentration, 27.9 +/- 2.27 microg/mL) occurred in the first 24 hours and remained above 2 microg/mL for 9 days. Gentamicin concentrations in control joints and the plasma remained below detectable levels. The synovial fluid WBC count for treated joints was increased compared with control joints for 72 hours, but was similar at day 6. The synovial protein concentration in gentamicin-treated joints remained increased for 21 days. Synovium in treated joints had diffuse synovitis, whereas control joints had less fibrovascular proliferation. Superficial cartilage erosion was present in all treated joints. There was no difference in the GAG content of treated and control joint cartilage. CONCLUSIONS: Short-term implantation of gentamicin (300 mg)-impregnated PMMA beads can provide therapeutic levels of gentamicin (>2 microg/mL) in the normal tarsocrural joint for 9 days; however, gentamicin-impregnated PMMA beads induce synovitis and superficial cartilage erosion. CLINICAL RELEVANCE: Temporary intra-articular administration of antibiotic-impregnated PMMA may be an effective way to treat septic joints that require constant high concentrations of antibiotics.     

Comparison of various treatments for experimentally induced equine infectious arthritis

To evaluate the effects of 5 treatments on clinical responses, synovial fluid analysis, radiographic changes, bacteriologic culture results of the synovial fluid and synovial membrane, microscopic characteristics of the synovial membrane, and articular cartilage histochemistry, Staphylococcus aureus organisms (1.6 X 10(6) colony-forming units) were inoculated into the tarsocrural joints of 12 horses (n = 24 joints; 2 joints/horse). Each horse was given phenylbutazone (2 g) orally, every 24 hours, beginning 24 hours after inoculation. Two horses (ie, 4 joints) were not given other treatment (controls; group 1). All other horses (ie, 20 joints) were given a trimethoprim-sulfadiazine combination orally, once daily (30 mg/kg; 8 joints) or twice daily (30 mg/kg q 12 hr; 12 joints). Each of these 20 joints were assigned to 1 of 5 treatment groups (4 joints/group) in a balanced incomplete block design. Group 2 (4 joints) was given only the antibiotics once daily. Twelve joints were treated by through-and-through joint lavage on day 1 (group 3), days 1 and 3 (group 4), or days 1, 3, and 6 (group 5). Joints in group 6 had an arthrotomy performed on day 1, with subsequent lavage via an indwelling drain every 12 hours for 4 days. In groups 3 through 6, 1 joint in each group was treated with antibiotics once daily, and 3 joints were treated with antibiotics twice daily. All horses were clinically assessed each day. Complete blood count was performed on days 3, 6, 10, and 21. Before inoculation and on days 0, 1, 3, 6, 10, and 21, synovial fluid specimens were collected and analyzed for color, clarity, total protein concentration, WBC count, differential count, and mucin clot-forming ability. Synovial fluid specimens were cultured bacteriologically before inoculation and on days 0 and 21. Horses in group 1 (controls) were euthanatized before day 6. All other horses were euthanatized on day 21. Tarsocrural joints were opened and examined. Synovial membrane specimens were bacteriologically cultured. Synovial membrane specimens were examined histologically (hemotoxylin and eosin stain) and articular cartilage specimens were (safranin O fast green stain) evaluated histochemically. Synovial membrane specimens were histologically graded into 5 categories. Intensity of articular cartilage intercellular staining with safranin 0 was graded for superficial, outer intermediate, inner intermediate, and deep zones. Two-way analysis of variance was performed to evaluate differences among groups and across time for the determinants evaluated.(ABSTRACT TRUNCATED AT 400 WORDS)     

EQUINE ARTHROGRAPHY

To obtain detailed radiographic information about the joint capsule, joint cavity, or articular cartilage, negative (air), positive, or double contrast arthrography is required. Negative and positive contrast arthrograms are easily obtained in a standing horse. Aseptic technique must be utilized. Aspiration of synovial fluid is followed by injection of contrast medium. For double contrast arthrography the horse must be anesthetized. After removal of some synovial fluid and the injection of air and positive contrast medium with the horse in lateral recumbency, the position of the horse is altered. Use of double contrast arthrography is limited to larger joints. In small joints distribution of air and positive contrast medium will be unequal, resulting in false-positive or false-negative findings. The diagnostic value of negative contrast arthrograms is relatively poor. Such arthrograms are useful only for the visualization of radiolucent joint mice or for the differentiation of intraarticular and extraarticular bone fragments. Positive contrast arthrograms are useful for the detection of larger synovial abnormalities, e.g., villonodular synovitis, herniation, or rupture of the joint capsule, or for the visualization of communication between the joint cavity and cystic bone lesions or cystic periarticular soft tissue masses. Double contrast arthrograms provide more detailed information than negative or positive arthrograms. Minor abnormalities of the articular cartilage or the synovial membrane can be visualized.     

Gentamicin concentrations in synovial fluid obtained from the tarsocrural joints of horses after implantation of gentamicin-impregnated collagen sponges

OBJECTIVE: To determine synovial fluid gentamicin concentrations and evaluate adverse effects on the synovial membrane and articular cartilage of tarsocrural joints after implantation of a gentamicin-impregnated collagen sponge. ANIMALS: 6 healthy adult mares. PROCEDURES: A purified bovine type I collagen sponge impregnated with 130 mg of gentamicin was implanted in the plantarolateral pouch of 1 tarsocrural joint of each horse, with the contralateral joint used as a sham-operated control joint. Gentamicin concentrations in synovial fluid and serum were determined for 120 hours after implantation by use of a fluorescence polarization immunoassay. Synovial membrane and cartilage specimens were collected 120 hours after implantation and evaluated histologically. RESULTS: Median peak synovial fluid gentamicin concentration of 168.9 microg/mL (range, 115.6 to 332 microg/mL) was achieved 3 hours after implantation. Synovial fluid gentamicin concentrations were < 4 microg/mL by 48 hours. Major histologic differences were not observed in the synovial membrane between control joints and joints implanted with gentamicin-impregnated sponges. Safranin-O fast green stain was not reduced in cartilage specimens obtained from treated joints, compared with those from control joints. CONCLUSIONS AND CLINICAL RELEVANCE: Implantation of a gentamicin-impregnated collagen sponge in the tarsocrural joint of horses resulted in rapid release of gentamicin, with peak concentrations > 20 times the minimum inhibitory concentration reported for common pathogens that infect horses. A rapid decrease in synovial fluid gentamicin concentrations was detected. The purified bovine type I collagen sponges did not elicit substantial inflammation in the synovial membrane or cause mechanical trauma to the articular cartilage.     

Primary degenerative joint disease of the shoulder in a colony of beagles

Shoulder joints of 149 Beagles over 8 years old at the time of death (mean age, 13.8 years +/- 3.21), were examined radiographically throughout their life-times for the frequency of degenerative joint disease (DJD). Clinical histories revealed no underlying cause for DJD. The shoulder joints of a subgroup of 18 dogs were examined at necropsy, and thin sections of the joints were evaluated radiographically and histologically. Serial clinical radiographic studies indicated that normal shoulder joint development during the first year of life was followed by the appearance of subchondral bone sclerosis and bony remodeling of normal joint contour, and by the formation of periarticular osteophytes and enthesiophytes. All changes were progressive with age and typical for DJD in dogs. Bilateral involvement was common. Evaluation of specimens obtained at necropsy revealed: articular cartilage change with roughening of the surface layer, degeneration and death of superficial chondrocytes, exposure of deeper layers of chondrocytes that had proliferated with fissuring of the damaged cartilage, total cartilage loss with polishing of the exposed subchondral bone, mixed patterns of subchondral bone sclerosis and osteoporosis, change in contour of the articular surfaces, and formation of periarticular osteophytes and enthesiophytes. Joint capsule thickening, synovitis, pannus formation, and synovial chondroma formation were observed. Because of the available clinical information, in addition to the typical changes of DJD, it was thought that the changes were primary. Instability appeared to play a role in the pathogenesis of the joint disease described; however, it was not clear whether the instability caused abnormal forces on healthy cartilage or whether the primary cartilage wear caused the instability.     

Use of vitamin B12 in joint lavage for determination of dilution factors of canine synovial fluid

OBJECTIVE: To test a modified saline (0.9% NaCl) solution joint washing (lavage) technique that includes the use of vitamin B12 as an internal marker for the evaluation of synovial fluid dilution in lavage samples from canine joints. SAMPLE POPULATION: 9 plasma samples obtained from blood samples of 9 healthy dogs and 9 synovial fluid samples aspirated from stifle joints of 9 cadaveric dogs. PROCEDURE: Photometric absorbances of 25% vitamin B12 solution, canine synovial fluid, and canine plasma were measured in a spectrophotometer to establish an optimal wavelength for analysis. Canine synovial fluid and plasma samples were mixed with the 25% vitamin B12 solution to obtain 1%, 3%, 5%, 10%, 20%, and 50% solutions of synovial fluid or plasma. Diluted synovial fluid and plasma samples were used to simulate joint lavage samples and to examine the possible interference of these substances (synovial fluid or plasma) with the absorbance of the 25% vitamin B12 solution in photometric analysis. RESULTS: The optimal wavelength was found to be at 550 nm. Canine synovial fluid and plasma samples did not interfere with the absorbance measurements of the 25% vitamin B12 solution up to a 50% dilution of plasma or synovial fluid. CONCLUSIONS AND CLINICAL RELEVANCE: The modified saline solution joint lavage method with the use of a 25% vitamin B12 solution as an internal standard provides an accurate and reliable technique for the evaluation of synovial fluid dilution in lavage samples from canine joints.