Evaluation of Postoperative Peritoneal Lavage in Standing Horses for Prevention of Experimentally Induced Abdominal Adhesions

Objective —To evaluate the postoperative use of peritoneal lavage for prevention of experimentally induced intraabdominal adhesions in horses.
Study Design —Areas of serosal abrasion were created on the jejunum of 12 horses. Postoperatively, six horses had peritoneal lavage, and six horses did not (controls). The number of adhesions was determined at necropsy 2 weeks after surgery.
Animals or Sample Population—12 horses.
Methods —Five sites of jejunal serosal abrasion were created in each horse. A 32 French thoracic catheter was placed into the right ventral aspect of the abdomen before closure of the abdominal incision. Treated horses had abdominal lavage with 10 L of lactated Ringer's solution on four occasions, then catheters were removed from all horses 34 hours after celiotomy. Horses were necropsied at 2 weeks to quantify the number of intraabdominal adhesions.
Results —All control horses and one treated horse developed intraabdominal adhesions. The number of adhesions was significantly less ( P <.0293) in treated horses. No adverse inflammatory reactions appeared to be associated with repeated peritoneal lavage using lactated Ringer's solution or use of an abdominal drain.
Conclusions —Peritoneal lavage reduced the frequency of intraabdominal adhesions.
Clinical Relevance —When postoperative adhesions are likely to develop, postoperative peritoneal lavage may decrease the frequency of adhesion formation.     

The Effect of Triple Pelvic Osteotomy on the Articular Contact Area of the Hip Joint in Dysplastic Dogs: An in Vitro Experimental Study

Objective —To investigate the effect of triple pelvic osteotomy (TPO) on articular contact area and acetabular coverage of dysplastic hip joints in dogs.
Study Design —Articular contact area and femoral head coverage by the acetabulum were computed in vitro in normal and dysplastic canine hips. The effect of TPO on articular contact and coverage was then analyzed in the dysplastic hips.
Sample Population—Five normal and six dysplastic canine cadaver specimens.
Methods —Contact area and coverage of loaded hips were computed using serial computed tomography scan images before and after TPO. Three angles of acetabular ventroversion (AVV) were studied (20°, 30°, and 40°). Using a custom-designed hinge plate, angles of spontaneous hip reduction in dysplastic hips were compared with previously recorded angles of reduction determined by the Ortolani test.
Results —Contact area significantly increased from 0° to 30° of AVV, then remained virtually unchanged. Coverage significantly increased from 0° to 20° of AVV. Both contact and coverage of normal hips were similar, yet significantly smaller than those of dysplastic hips once reduction had occurred. The experimental angles of reduction were significantly smaller and poorly correlated with the angles of reduction determined by the Ortolani test. Although coverage continued to increase with AVV, the actual joint contact area did not significantly vary after relocation of the femoral head.
Conclusions —This study suggests that increasing AVV beyond 20° does not significantly improve the beneficial effects of TPO and therefore should be carefully weighed against increased risks of postoperative complications associated with large angles of AVV.     

Intra-articular Anesthesia of the Distal Interphalangeal Joint Alleviates Lameness Associated With the Navicular Bursa in Horses

Objective — To determine if intra-articular anesthesia of the distal interphalangeal joint could alleviate lameness associated with the navicular bursa in horses.
Study Design — Experimental investigation.
Animals — Six clinically normal horses.
Methods — Lameness was induced in each horse by injecting either the left or right front navicular bursa with 5 mg of amphotericin-B. Forty-eight hours later each horse was videotaped walking and trotting before, and 5, 30, and 60 minutes after injecting the distal interphalangeal joint of the treated limb with 5 mL of 2% mepivacaine hydrochloride. All video recordings were then rerecorded onto master tapes in a random sequence. Four clinicians, unaware of the animal identity related to observation time or limb treated, independently viewed these tapes and graded the lamenesses.
Results — There was a significant reduction in lameness 5 and 30 minutes after anesthetic was injected into the distal interphalangeal joint. Lameness scores 60 minutes after anesthetic administration were not significantly different than baseline values. Gross pathological examination confirmed marked inflammation of the treated navicular bursae and normal appearance of the distal interphalangeal joints.
Conclusions — Intra-articular anesthesia of the distal interphalangeal joint can alleviate lameness associated with the navicular bursa.
Clinical Relevance — Intra-articular anesthesia of the distal interphalangeal joint is not specific only for lameness originating in the distal interphalangeal joint.     

Canine Vaginal Cytology—III Compilation and Evaluation of Cellular Indices

Abstract— —The establishment of indices for the vaginal cellular elements and the practical significance of these in canine reproduction is emphasised.
Résumé— —L'établissement d'indices pour les éléments cellulaires vaginaux et leur importance dans la reproduction canine est souligné.
Zusammenfassung— —Die Aufstellung von Tabellen für Scheidezellengrundstoffe und die praktische Bedeutung derselben für die Fortpflanzung von Hunden wird hervorgehoben.     

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.     

Reduction in Plate Strain by Addition of an Intramedullary Pin

Objective —The purpose of this study was to determine the strain sparing effect of a bone plate and rod system compared with a bone plate alone.
Study Design —Mathematical analysis and in vitro modeling of implant-bone constructs. Implants were instrumented with uniaxial strain gauges.
Animals or Sample Preparation —Five pairs of canine femurs.
Methods —Bone plates were instrumented with two 350-ohm strain gauges. The bone plates were used to bridge a simulated fracture gap in five pairs of canine femurs. In one femur of each pair, a bone plate alone was used to bridge the gap; in the opposite femur, a bone plate and intramedullary rod combination was used. Each specimen was mounted on a custom jig and loaded in an axial servohydraulic testing machine. A constantly increasing compressive load was applied at the rate of 0.7 cm/sec. Strains at 400.5 N were recorded and analyzed using Wilcoxon's signed rank test. Mathematical modeling was done using parallel beam theory.
Results —Stress reduction in the plate and rod system was twofold compared with the plate alone ( P = .059). As important, based on stress reduction in the plate, the fatigue life of the plate/rod system increased 10-fold over the plate system alone and was greater than 10-fold at higher absolute stress values. Mathematical analysis of the plate/rod system was similar to that seen with the in vitro analysis.
Conclusions —The combination of a bone plate and intramedullary pin was superior in reducing plate stress when compared with the plate alone and functioned as two beams acting in concert.
Clinical Relevance —Stabilization of comminuted fractures by bridging the zone of fragmentation with a bone plate without anatomic reduction of each fragment is a useful method of managing this type of injury. Addition of an intramedullary pin reduces the stress applied to the plate and thereby extends the fatigue life of the bone plate.     

Chlorhexidine Diacetate and Povidone-iodine Cytotoxicity to Canine Embryonic Fibroblasts and Staphylococcus aureus

Chlorhexidine diacetate and povidone-iodine were evaluated for fibroblast toxicity on a primary line of canine embryonic fibroblasts, and for bactericidal efficacy against Staphylococcus aureus. The cultured fibroblasts or S. aureus were exposed for 30 minutes to incremental dilutions of 0.5 and 0.0005% chlorhexidine diacetate, 5.0 to 0.05% povidone-iodine, or physiologic buffered saline as a control. To determine survival, fibroblasts were trypsinized and counted; S. aureus colonies were counted on brain-heart infusion agar. Survival for both groups was expressed by calculating the number of living cells in test dilutions as a percentage of the number in control cultures. Fibroblast survival occurred at chlorhexidine concentrations less than 0.013% and at povidone-iodine concentrations less than 0.5% (p less than 0.05). Significant S. aureus survival (p less than 0.05) was noted at chlorhexidine concentrations less than 0.05% and povidone-iodine concentrations less than 1.0%. These data showed that all bactericidal concentrations of chlorhexidine diacetate and povidone-iodine were lethal to canine embryonic fibroblasts in vitro, whereas non-lethal concentrations allowed significant bacterial survival.     

Short-Term Hemodynamic Evaluation of Circumferential Mitral Annuloplasty for Correction of Mitral Valve Regurgitation in Dogs

Objective —To determine the short-term hemodynamic effects associated with circumferential mitral annuloplasty (CMA) in dogs with mitral regurgitation.
Study Design —Prospective experimental study.
Animals —Seven healthy adult mongrel dogs.
Methods —Mitral regurgitation was surgically induced, and annular dilation occurred. Echocardiography and cardiac catheterization were used to determine forward ejection fraction (FEF), regurgitant fraction (RF), pulmonary capillary wedge pressure (PCWP), and annular diameter before and immediately after CMA in five dogs. FEF and RF were also evaluated 7 days after annuloplasty.
Results —Mean annular diameter and PCWP were significantly reduced immediately after CMA. Significant increases in FEF of 19% and 22% were shown immediately and 7 days after CMA. Significant reductions in RF of 19% and 22% were also shown immediately and 7 days after annuloplasty.
Conclusions —Sustained hemodynamic benefits and a reduction in annular diameter were achieved by CMA in a canine model of mitral regurgitation.
Clinical Implications—CMA may be a suitable treatment for heart failure because of mitral regurgitation when early signs of cardiovascular decompensation persist despite appropriate medical management.     

Radiographic, Densitometric, and Biomechanical Effects of Recombinant Canine Somatotropin in an Unstable Ostectomy Gap Model of Bone Healing in Dogs

Objective —To determine the effect of recombinant canine somatotropin (STH) on radiographic, densitometric, and biomechanical aspects of bone healing using an unstable ostectomy gap model.
Study Design —After an ostectomy of the midshaft radius, bone healing was evaluated over an 8–week period in control dogs (n = 4) and dogs receiving recombinant canine STH (n = 4).
Animals or Sample Population—Eight sexually intact female Beagle dogs, 4 to 5 years old. Methods—Bone healing was evaluated by qualitative and quantitative evaluation of serial radiographs every 2 weeks. Terminal dual-energy x-ray absorptiometry and three-point bending biomechanical testing were also performed.
Results —Dogs receiving STH had more advanced radiographic healing of ostectomy sites. Bone area, bone mineral content, and bone density were two to five times greater at the ostectomy sites of treated dogs. Ultimate load at failure and stiffness were three and five times greater in dogs receiving STH.
Conclusions —Using the ostectomy gap model, recombinant canine STH enhanced the radiographic, densitometric, and biomechanical aspects of bone healing in dogs. Clinical Relevance—Dogs at risk for delayed healing of fractures may benefit from treatment with recombinant canine STH.     

Evaluation of wraps covering the distal aspect of pelvic limbs for prevention of bacterial strike-through in an ex vivo canine model

Objective— To determine differences in bacterial strike-through for materials commonly used to cover the distal aspect of the pelvic limb during operative site preparation.
Study Design— Randomized block design; ex vivo model.
Animals— Canine cadaveric pelvic limbs (n=40).
Methods— Pelvic limbs (n=40) were randomly assigned to 4 treatment groups: Group 1=Vetrap^™+sterile Coban^™; Group 2=latex glove+Vetrap^™+sterile Coban^™; Group 3=latex glove+Vetrap^™+sterile Coban^™+sterile latex glove+sterile Coban^™; and Group 4=latex glove+Vetrap^™+sterile disposable drape+sterile Coban^™. Limbs were contaminated with a standardized bacterial solution and routinely prepared using the assigned distal leg wrap. Bandages were fluid challenged with a saline (0.9% NaCl) solution-soaked laparotomy sponge for 30 seconds. The wrap surface was sampled for microbial culture before surgical preparation, immediately after, and 60 minutes after applying a sterile leg wrap.
Results— Bacterial growth occurred in all Group 1 cultures, 90% of Group 2 cultures, and none of the Group 3 and 4 cultures, 60 minutes after applying the sterile wrap.
Conclusion— A distal leg wrap of Vetrap^™+sterile Coban^™ is not effective in preventing bacterial strike-through.
Clinical Relevance— If similar results occur in the live animal, then a sterile impermeable barrier must be incorporated into the distal leg wrap to prevent bacterial strike-through.     

The Effects of Active Peripheral Skin Warming on Perioperative Hypothermia in Dogs

Objective — This study evaluates the efficacy of three perioperative warming protocols to improve control of body temperature in anesthetized dogs.
Study Design — A randomized controlled clinical trial.
Animals or Sample Population — Thirty-two client-owned dogs.
Methods — We prospectively studied dogs entering the University of Pennsylvania Veterinary Teaching Hospital for orthopedic or dental procedures and assigned them to one of three perianes-thetic warming protocols. Group 1 (n = 10) had a single circulating warm water mattress applied over the trunk (single-trunk warming). Group 2 (n = 12) had two circulating warm water mattresses, one placed over and one under the trunk (double-trunk warming). Group 3 (n = 10) had warm circulating mattresses applied only around the feet and legs of all available limbs (peripheral warming). The warm water mattresses were prewarmed and maintained at 40°C (104°F) and applied immediately after induction of general anesthesia. All dogs had a layer of thick terry cloth toweling beneath and above the trunk. Body temperature measurements were recorded every 15 minutes for the first 2.5 hours of anesthesia.
Results — The lowest mean temperature for dogs in group 3 was 37.4 ± 0.2°C (99.5°F), compared with 36.4 ± 0.2°C (97.4°F) and 36.7 ± 0.2°C (98.0°F) in groups 1 and 2, respectively.
Conclusions — Dogs in the peripheral warming group maintained significantly higher core body temperatures than dogs in either trunk warming groups throughout the 2.5-hour study period.
Clinical Relevance — To maintain body heat in dogs during anesthesia, it is more effective to warm the feet and legs than to warm the trunk.     

Bacterial Isolates From Plaque and From Blood During and After Routine Dental Procedures in Dogs

Objective — This study evaluates the association between dental procedures and bacteremia in dogs, including a comparison of bacteria isolated from plaque and blood, severity of the bacteremia versus the severity of dental disease, and the longevity of bacteremia.
Study Design — Bacteria cultured from the blood over time were compared with those isolated from the plaque and crevicular fluid and in relation to severity of dental disease.
Animals or Sample Population — Twenty adult greyhounds.
Methods — Blood samples were collected for culture before induction of general anesthesia, immediately after intubation, 20 minutes after initiation of the dental procedure, and at 10-minute intervals until 10 minutes after the dental procedure was completed. Samples of plaque were taken for microbiological culture.
Results — Sixty to ninety percent of the bacterial genera isolated from the plaque were present in the blood. Dogs classified according to severity of dental disease showed no difference in the total number of different species or number of different Gram-negative, Gram-positive, or anaerobic bacteria isolated from plaque or blood (P <.05). Bacteremia was present in all of the dogs studied, within 40 minutes from the initiation of the dental procedure, regardless of the severity of oral disease.
Conclusions — Gram-negative, Gram-positive, and anaerobic bacteria are present in blood during dental procedures; the bacteremia can persist beyond the dental procedure, and is not associated with the severity of dental disease.
Clinical Relevance — The nature and extent of bacteremia occuring during routine dental procedures is important in understanding a potential risk to dogs.     

Anesthetic Potency of Desflurane in the Horse: Determination of the Minimum Alveolar Concentration

Objective — To determine the minimum alveolar concentration (MAC) of desflurane (DES) in the horse.
Study Design — Prospective study.
Animals — Six healthy adult horses (three males and three females) weighing 370 ±16 kg and aged 9 ±2 years old.
Methods — Anesthesia was induced with DES vaporized in oxygen via a face mask connected to a large-animal, semiclosed anesthetic circle system. The horses were endotracheally intubated and positioned in right lateral recumbency. Inspired and end-tidal DES were monitored using a calibrated Ohmeda RGM 5250 multigas analyzer (Ohmeda-BOC, Spain). The MAC of desflurane that prevented gross purposeful movement in response to 60 seconds of noxious electrical stimulation of oral mucous membranes was determined.
Results — The time from the start of DES administration to lateral recumbency was 6.1 ±0.9 min. The MAC of DES in these horses was 7.6 ±0.4%. Time required for the animal to regain sternal recumbency after 98 ±4 minutes of anesthesia was 6.6 ±0.5 minutes and the time to standing was 14.3 ±2.7 minutes.
Conclusions — The MAC of desflurane in these horses was 7.6 ±0.4%. DES provided a rapid induction to, and recovery from, anesthesia.
Clinical Relevance — Desflurane offers the potential for more precise control during anesthesia, and may allow a faster and uneventful recovery. It is important to know the MAC of an inhalant to use it clinically.     

Ventral Abdominal Approach for Laparoscopic Ovariectomy in Llamas

Objective —To evaluate a technique for laparoscopic ovariectomy by a ventral abdominal approach in the llama.
Study Design —Prospective evaluation.
Animal Population —Six healthy adult female llamas, aged 2 to 6 years.
Methods —Laparoscopic ovariectomy was performed with the llamas in a 30-degree Trendelenburg position. The mesovarium and proper ligament of the ovary were isolated, and two Hulka clips were placed in opposite directions across each mesovarium and proper ligament of the ovary. Ovaries were removed through either the instrument cannula or instrument portal.
Results —The ovaries, mesovarium, and proper ligaments of the ovaries were easily identified using laparoscopy by a ventral abdominal approach. The Hulka Clip Applicator was easy to use, and the Hulka Clips provided secure hemostasis of the vessels within the mesovarium. Mean duration of surgery was 35 minutes (range, 17 to 85 minutes). Two llamas were depressed after surgery but improved within 24 hours. No other complications occurred during an 18-month follow-up period.
Conclusions —Laparoscopic ovariectomy in the llama was facilitated by the use of Hulka Clips placed across the mesovarium and proper ligament of the ovary.
Clinical Relevance —Laparoscopic ovariectomy in the llama can be accomplished easily with few complications.     

Comparison of nuclear morphometric parameters in cytologic smears and histologic sections of spontaneous canine tumors

Background — Nuclear morphometry may provide useful diagnostic and prognostic information for neoplasms in animals. Most available data have been obtained from histologic sections. Nuclear morphometry of cytologic smears may provide important pre-operative information.
Objectives — The goal of this study was to compare nuclear morphometric parameters in cytologic smears and histologic sections from spontaneous canine tumors.
Methods — Mean nuclear area (MNA), mean nuclear perimeter (MNP), mean nuclear form factor (FF; nuclear perimeter²/4π nuclear area) and their respective SDs were assessed by image analysis of both hematoxylin and eosin-stained histologic sections and May-Grünwald-Giemsa-stained cytologic smears from the same case in 20 spontaneous canine tumors of different histogenesis. The above parameters were selected as being the best morphometric tools for measuring variation in shape and size in cells after neoplastic transformation. Data were compared by ANOVA with P<.01 considered significant.
Results — There was a significant difference between histologic and cytologic specimens for MNA, MNP, and their SDs. Only the differences between FF and the SD of FF were not statistically significant.
Conclusions — Only nuclear morphometric data related to nuclear shape and nuclear shape variability are comparable between histologic and cytologic specimens. Nuclear area and perimeter may be affected by the different fixation and smear preparation techniques used in histology and cytology.     

Detection of canine microalbuminuria using semiquantitative test strips designed for use with human urine

Background — Commercial testing for microalbuminuria in human urine is often performed with point-of-care semiquantitative test strips followed by quantitative testing when indicated. An ELISA that quantifies canine urine albumin concentration has been developed, but semiquantitative test strips for use in the dog are not available.
Objective — The purpose of this study was to prospectively determine the concordance of canine urine albumin concentrations measured by a commercial human test strip and by ELISA.
Methods — Urine samples were obtained from 67 dogs evaluated for a variety of clinical conditions. Dipstick urinalyses were performed on all samples; clinician discretion determined method of urine collection and performance of urine sediment examination and/or urine culture. Urine albumin concentration was determined using test strips (Clinitek Microalbumin, Bayer Corporation, Elkhart, Ind, USA), and results were compared with those obtained by ELISA.
Results — The Clinitek strips correctly determined albumin concentration in 42 of 67 (63%) urine samples tested. Concordance was lowest (48%) for dogs with microalbuminuria (10–300 μg/mL by ELISA). Clinitek strip sensitivity and specificity for correct identification of microalbuminuria were 48% and 75%, respectively. Concordance was lower in dogs with urinary tract infection or hematuria and in samples collected by catheterization. Sensitivity and specificity for correct identification of microalbuminuria after exclusion of dogs with urinary tract infection or hematuria were 59% and 83%, respectively.
Conclusion — These results suggest that the Clinitek strips lack sufficient concordance with results obtained by ELISA to be reliable screening tests for microalbuminuria in the dog. A reliable semiquantitative point-of-care test for canine urine albumin concentrations below those detected by standard urine dipsticks is still needed.     

Biomechanical Comparison of the Trocar Tip Point and the Hollow Ground Tip Point for Smooth External Skeletal Fixation Pins

Objective —To compare the insertional characteristics of external fixator pins with hollow ground (HG), modified HG, and trocar (T) points.
Study Design —An acute, in vitro biomechanical evaluation.
Sample Population—Thirteen radii from canine cadavers.
Methods —A total of 16 T-tipped and 16 HG-tipped pins were inserted into 8 canine radii. Ten pins of each modification of the HG tip (length of the cutting edge reduced by 0.127 mm and 0.254 mm, respectively) were inserted into another five radii. All pins were inserted with low-speed power drilling and 80 N drilling load. Differences between peak tip temperature, drilling energy, and pullout force were determined for each pin type at both diaphyseal and metaphyseal locations.
Results —HG-tipped pins showed a 40% lower tip temperature in diaphyseal bone, a 25% reduction in drilling energy in diaphyseal bone, and a reduction of pullout force in both diaphyseal (65%) and metaphyseal (50%) bone compared with T-tipped pins. HG 0.254-mm pins generated higher tip temperatures and had greater pullout than HG pins in diaphyseal bone.
Conclusions —The HG tip was a more efficient design; however, the reduction in pullout force suggests that, because a better hole was drilled, radial preload is reduced. Reduction of the cutting edge by 0.254 mm increased the pullout force but also increased the temperatures.
Clinical Relevance —Thermal and microstructural damage are reduced by the HG tip, but pin-bone interface stability is also compromised. The use of a tip with 0.254 mm reduction in the cutting edge may optimize the biological and mechanical factors at the pin-bone interface.     

Dissipation of Heat During Polymerization of Acrylics Used for External Skeletal Fixator Connecting Bars

Objective — To determine the amount of heat conducted by transfixation intramedullary pins (IP) and Kirschner wires (KW) during polymerization of acrylics used for external skeletal fixator (ESF) connecting bars.
Study Design — Thermal conduction was measured using thermistors applied to IP and KW surfaces during the polymerization phase of acrylics.
Methods — Type II ESF were created from IP or KW placed into wooden dowels and plastic tubing used to create connecting bars filled with one of two types of acrylic (Acrylic Pin External Fixation System or Technovit, Jorgensen Laboratories, Loveland, CO). Thermistors were positioned on the acrylic column surface and on IP or KW surfaces 5 or 10 mm from the acrylic column. Five ESF test groups were created. The maximum temperature (Tmax) of the acrylic column (Tmax-A), IP (Tmax-IP), KW (Tmax-KW), and duration that Tmax-IP or Tmax-KW remained greater than or equal to 55°C were calculated.
Results — All IP and KW thermistors placed 5 mm from acrylic columns reached mean temperatures greater than 50°C and had peak temperature ranges greater than 55°C compared with all IP and KW thermistors placed 10 mm from the acrylic columns in all groups. Thermistors placed 5 mm from the acrylic column in two groups maintained temperatures greater than 55°C for greater than or equal to 0.5 minutes.
Conclusions — Acrylic columns positioned 5 mm from a thermistor on a IP or KW had the potential to reach or exceed temperatures that have been reported to cause thermal necrosis of tissues.
Clinical Relevance — Acrylic Pin External Fixation System or Technovit acrylic connecting bars used in ESF designs have the potential to cause thermal injury to soft and bony tissue by thermal conduction along transfixation pins or wires.     

Changes in Third Carpal Bone Articular Cartilage After Synovectomy in Normal and Inflamed Joints

Objective —To determine if arthroscopic synovectomy in normal and inflamed joints had temporal or site-related effects on articular cartilage.
Study Design —Alterations in equine third carpal bone articular cartilage were studied at two time periods: groups 1 and 2 (6 weeks) and groups 3 and 4 (2 weeks) after synovectomy in normal (groups 2 and 4) and inflamed carpi (groups 1 and 3).
Animal Population —16 carpi from eight horses.
Methods —Biochemical and biomechanical properties of dorsal and palmar articular cartilage were determined by radiolabeling, proteoglycan (PG) extraction, chromatography, electrophoresis, and indentation testing.
Results —Synovectomy in inflamed joints produced the greatest concentration of newly synthesized PG in articular cartilage by 2 weeks. Synovectomy in normal joints produced significantly greater newly synthesized PG in articular cartilage by 6 weeks. Endogenous PG was only significantly greater in inflamed joints after 6 weeks. Dorsal sites had greater newly synthesized and endogenous PG in some groups. Chromatographic profiles of newly synthesized PG demonstrated early and late PG peaks. Electrophoresis of late PG peak showed a toluidine blue-positive band that comigrated with human A1D1 PG monomer in the two groups with the most newly synthesized PG. This band was reactive with monoclonal antibody 1C6 specific for the hyaluronic acid-binding region of aggrecan. For the material properties evaluated, only Poisson's ratio was significantly decreased between groups as a function of time (6 weeks < 2 weeks), and this was most pronounced in the thicker dorsal sites.
Conclusions —Synovectomy in inflamed joints produced site-specific, significantly greater responses in articular cartilage as compared with synovectomy in normal joints.
Clinical Relevance —Synovectomy may not be beneficial to the articular cartilage in inflamed joints.