Immune cell profiling in the joint following human and murine articular fracture.

OBJECTIVE: Human and in vivo animal research implicates inflammation following articular fracture as contributing to post-traumatic arthritis. However, relevant immune cell subsets present following injury are currently undefined. Immunophenotyping human and murine synovial fluid may help to identify immune cell populations that play key roles in the response to articular fracture. METHODS: Immunophenotyping by polychromatic flow cytometry was performed on human and mouse synovial fluid following articular fracture. Specimens were collected in patients with closed ankle fracture at the time of surgical fixation and from C57BL/6 mice with closed articular knee fracture. Immune cells were collected from injured and uninjured joints in mice via a novel cell isolation method. Whole blood samples were also collected. Immunohistochemistry (IHC) was performed on mouse synovial tissue to assess for macrophages and T cells. RESULTS: Following intra-articular fracture, the prominent human synovial fluid immune cell subset was CD3+ T cells, containing both CD4+ and CD8+ T cells. In mice, infiltration of CD45+ immune cells in synovial fluid of the fractured limb was dominated by CD19+ B cells and CD3+ T cells at 7 days after intra-articular fracture. We also detected adaptive immune cells, including macrophages, NK cells, dendritic cells and monocytes. Macrophage and T cell findings were supported by IHC of murine synovial tissue. CONCLUSIONS: Determining specific cell populations that mediate the immune response is essential to elucidating the chain of events initiated after injury and may be an important step in identifying potential immune signatures predictive of PTA susceptibility or potential therapeutic targets.

Global metabolic profiling of human osteoarthritic synovium.

Osteoarthritis (OA) is a debilitating disease associated with pain and loss of function in numerous diarthrodial joints of the body. Assessments of the severity and/or progression of OA are commonly based on radiographic stages and pain level, which aren't always correlated to severity of disease or joint dysfunction and may be confounded by other factors(1). There has been recent interest in identifying a biochemical signature of OA(1) that may be detected in serum, urine, and/or synovial fluid that would represent repeatable and predictable biomarkers of OA onset and/or progression. The objective of this study was to use global metabolic profiling to identify a distinct metabolic profile for cultured human synovial tissue from patients with end-stage OA compared to patients with little or no evidence of disease. While metabolic profiles from cultured tissues are not expected to reproduce in vivo profiles, it is expected that perturbations in metabolism caused by end-stage disease would result in differences in metabolic profiles in vitro compared to tissue with little or no evidence of disease. Because metabolomic perturbations often occur prior to alterations in the genome or proteome, metabolomic analysis possibly provides an earlier window to an altered biochemical profile for OA onset and/or progression, and may provide a unique set of potential drug targets. The synovium was targeted because it has been implicated in OA as a mediator of disease progression; osteoarthritic synovium has been demonstrated to express pro-inflammatory cytokines, such as Tumor Necrosis Factor - α (TNF-α), Interleukin-1 ß (IL-1ß), and IL-6(2), suggesting that a diseased synovial lining could produce an ideal set of biomarkers for diagnosing OA and/or monitoring disease progression. Media from the culture of synovial explants dissected from diseased human joints (early or end-stage OA) was subjected to global metabolic profiling with a liquid chromatography (LC)/and gas chromatography (GC)/mass spectrophotometry (MS)-based technology platform. Metabolites were identified by automated comparison of the ion features in the experimental samples to a reference library of chemical standard entries developed at Metabolon, Inc (Durham, NC). Global metabolic profiling resulted in the identification of 105 distinct compounds across all sample groups, with 11 compounds showing significantly different relative concentrations between end-stage and no/early disease groups. Metabolites specific to collagen metabolism, branched-chain amino acid metabolism, energy metabolism and tryptophan metabolism were amongst the most significant compounds, suggesting an altered metabolic state with disease progression.

Coronal plane ankle alignment, gait, and end-stage ankle osteoarthritis.

OBJECTIVE: Unilateral ankle osteoarthritis (OA) is a debilitating condition which may lead to limb deformity, severe pain, and functional disability due to tibiotalar malalignment and gait dysfunction. The purpose of this study was to determine if coronal plane alignment (varus, valgus, or neutral) of the ankle resulted in different spatial-temporal gait mechanics, clinically-assessed function, and self-reported function in patients with end-stage ankle OA. METHODS: Following informed consent, 96 patients with end-stage unilateral ankle OA were radiographically categorized as having varus, valgus, or neutral tibiotalar alignment. Each subject completed the foot and ankle disability index (FADI) questionnaire to assess self-reported function. The spatial-temporal parameters of interest (stance time, step length, stride length, stride width, single-support time, double support time, and walking speed) were assessed while the subject walked at a self-selected speed. RESULTS: The varus group performed the timed up and go test significantly faster than the other groups (P=0.05). All other variables were similar between the three alignment groups. CONCLUSION: There was little difference in gait mechanics and function between patients with end-stage OA based on coronal plane ankle alignment suggesting that factors other than coronal plane alignment contribute to diminished function.

Intermediate-term results of the Ludloff osteotomy in one hundred and eleven feet.

BACKGROUND: The modified Ludloff proximal first metatarsal osteotomy is indicated for the surgical correction of moderate-to-severe hallux valgus deformity associated with metatarsus primus varus. We report the intermediate-term results of this procedure. METHODS: Ninety-nine patients (111 feet) with a mean age of fifty-six years underwent a modified Ludloff proximal first metatarsal osteotomy and a distal soft-tissue procedure at two institutions for the treatment of a moderate-to-severe hallux valgus deformity. The American Orthopaedic Foot and Ankle Society score and weight-bearing radiographs of the foot were assessed preoperatively and after a mean duration of follow-up of thirty-four months. Clinical and radiographic outcome was also compared between younger and older patients, with the arbitrarily chosen age of sixty years dividing the two groups. RESULTS: The mean American Orthopaedic Foot and Ankle Society score improved significantly (p < 0.0001) from 53 points preoperatively to 88 points at the time of the most recent follow-up. The mean American Orthopaedic Foot and Ankle Society score for patients who were sixty years of age or less was significantly higher than that for patients who were more than sixty years of age (91 compared with 83 points; p = 0.0057). The mean hallux valgus angle decreased significantly from 35 degrees preoperatively to 9 degrees at the time of the most recent follow-up (p < 0.0001), and the mean intermetatarsal angle decreased significantly from 17 degrees to 8 degrees (p < 0.0001). All osteotomy sites united without dorsiflexion malunion but with a mean first metatarsal shortening of 2.2 mm. CONCLUSIONS: To our knowledge, the present report describes the largest cohort of patients undergoing a modified Ludloff osteotomy for the correction of hallux valgus deformity that has been reported in the literature. Our intermediate-term results demonstrate that the procedure achieves significant correction of moderate-to-severe hallux valgus deformity, significant reduction in forefoot pain, and significant improvement in functional outcome. Patients with an age of sixty years or less appear to have a more favorable outcome.

Arthrodesis of the talocalcaneal joint for the treatment of two horses with talocalcaneal osteoarthritis.

Two horses with lameness due to tolocalcaneal osteoarthritis that failed to respond to conservative management were treated by tolocalcaneal arthrodesis using cortex screws placed in lag fashion. The affected joint of one horse was arthrodesed by compressing and stabilizing the medial facet of the joint with three screws. In the second horse, the medial and lateral facets of the affected tolocalcaneal joint were each compressed and stabilized with two screws. The lameness of both horses improved markedly following surgery.

A new approach for assessing early osteoarthritis in the rat.

Several animal models have been developed to investigate osteoarthritis and potential disease-modifying therapeutics. However, early disease data from these models are limited by the resolution of current imaging modalities. In this in-vitro study, an optical coherence tomography (OCT) system with an axial resolution of 15 micro m was used to track sequential changes in osteoarthritic rat knees. Osteoarthritis was induced via transection of the medial collateral ligament and an artificial full thickness meniscal tear. Imaging occurred at one, two, and three weeks after surgery. OCT successfully detected early signs of osteoarthritic change, including alteration of the cartilage surface and disruption of the bone-cartilage interface. This study demonstrates that OCT, along with the induction of mechanical injury, provides an excellent model for monitoring the sequential changes of osteoarthritis.

New technology for assessing microstructural components of tendons and ligaments.

This study investigated the ability of optical coherence tomography (OCT), a recently developed technology with micron-scale resolution, to assess the microstructure of tendons and ligaments. In vitro structural- and polarization-sensitive OCT was performed on human ACL, Achilles tendon, and biceps tendon (obtained postmortem). Histology was performed on all imaged samples and compared to the corresponding OCT data. OCT images correlated well with histology. Most importantly, through polarization-sensitive OCT, the collagen in normal tissue was easily distinguished from the surrounding, supportive tissue due to the birefringent properties of organized collagen. Since the integrity of collagen is an important indicator of structural stability and pathologic state, the ability of OCT to assess collagen could be a powerful diagnostic tool in assessing tendon and ligament properties.

Degree of antigen adsorption in the vaccine or interstitial fluid and its effect on the antibody response in rabbits.

The effect of the degree of adsorption of lysozyme by aluminium hydroxide adjuvant on the immune response in rabbits was studied. The surface charge of the adjuvant was modified by pretreatment with phosphate anion to produce five vaccines having degrees of adsorption ranging from 3 to 90%. The degree of adsorption of vaccines exhibiting 3, 35 or 85% adsorption changed to 40% within 1 h after each vaccine was mixed with sheep interstitial fluid to simulate subcutaneous administration. The mean anti-lysozyme antibody titers produced by the vaccines were the same and were four times greater than that produced by a lysozyme solution. Thus, the degree of adsorption of lysozyme in sheep interstitial fluid rather than the degree of adsorption in the vaccine correlated with the immune response.

Surgical implantation of ultrafiltration probes in ovine bone and muscle.

It may be desirable to collect compounds directly from sites of interest if blood concentrations do not reflect tissue levels. Ultrafiltration and microdialysis probes may be used to do this, but the hollow fibers of these probes are quite fragile. For this reason, we developed a pull-through technique that allows their implantation into the ovine quadriceps muscle and femur. The sheep is placed under anesthesia in lateral recumbency. An incision is made midway between the patella and greater trochanter directly over the lateral femur. A hand drill is used to make a 4.5-mm hole into the medullary cavity through the lateral cortex of the distal femur. A second incision is then made over the greater trochanter. The drill bit is inserted into the trochanteric fossa and a hole is drilled distally through the medullary cavity of the femur to the level of the first hole. A looped 20-gauge wire is then inserted into the femur and removed through the distal hole. Suture is attached, and the wire is withdrawn, leaving the suture in place. The suture is tied to the ultrafiltration probe tubing, allowing the probe to be carefully drawn into position. For implantation into the muscle, a 10-gauge introducer is used. The introducer is placed through the quadriceps muscle and the probe is then threaded through it. This technique has been successfully performed on 18 sheep. All sheep tolerated the procedure well. Up to 2.0 mL/day of interstitial fluid was recovered from each site. The average lifetimes of the bone and muscle probes were 35 and 40 days, respectively.

Osseous sequestration in cattle: 110 cases (1987-1997).

OBJECTIVE: To determine risk factors for development of sequestra in cattle and identify factors associated with a successful outcome. DESIGN: Retrospective study. ANIMALS: 110 cattle. PROCEDURE: Medical records of cattle treated at veterinary teaching hospitals in North America were reviewed. To determine risk factors for osseous sequestration, breed, age, and sex of cattle with osseous sequestration were compared with breed, age, and sex of all other cattle admitted during the study period. RESULTS: 110 cattle were included in the study. Three had 2 sequestra; thus, 113 lesions were identified. Most sequestra were associated with the bones of the extremities, most commonly the third metacarpal or third metatarsal bone. Ninety-two animals were treated surgically (i.e., sequestrectomy), 7 were treated medically, 3 were initially treated medically and were then treated surgically, and 8 were not treated. Follow-up information was available for 65 animals treated surgically and 6 animals treated medically. Fifty-one (78%) animals treated surgically and 5 animals treated medically had a successful outcome. Cattle that were 6 months to 2 years old had a significantly increased risk of developing a sequestrum, compared with cattle < 6 months old. Cattle in which sequestrectomy was performed with the aid of local anesthesia were significantly more likely to undergo 2 or more surgical procedures than were cattle in which sequestrectomy was performed with the aid of general anesthesia. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggest that sequestrectomy will result in a successful outcome for most cattle with osseous sequestration.

Long-term outcome of horses with a slab fracture of the central or third tarsal bone treated conservatively: 25 cases (1976-1993).

OBJECTIVE: To determine clinical features of horses with a slab fracture of the central or third tarsal bone and to report outcome of horses in which treatment did not include surgery. DESIGN: Retrospective study. ANIMALS: 25 horses (14 Standardbreds, 6 Thoroughbreds, 5 Quarter Horses). PROCEDURE: Medical records of horses with a slab fracture of the central (n = 9) or third (16) tarsal bone were reviewed. Only horses for which treatment consisted of confinement to a stall were included in this study. Clinical features and radiographic findings were recorded and summarized. Outcome was determined for racing breeds by obtaining official lifetime race results. Outcome for Quarter Horses was determined by phone survey of the owners. RESULTS: 16 (64%) horses had a successful outcome. Ten of 14 (71%) Standardbreds and 2 of 6 Thoroughbreds returned to racing and started at least 5 races after injury. Four of 5 Quarter Horses for which follow-up information was available successfully returned to their previous activity. Sex, age, limb affected, or gait was not associated with final outcome. Percentage of racehorses with central tarsal bone fractures that had a successful outcome (2/7) was significantly less than percentage with third tarsal bone fractures that did (10/13). CONCLUSIONS AND CLINICAL RELEVANCE: Results suggest that enforced rest without surgical fixation can be an effective therapeutic option for horses with a slab fracture of the central or third tarsal bone, even if athletic function is expected.

Continuous infusion of gentamicin into the tarsocrural joint of horses.

OBJECTIVE: To develop a method for continuous infusion of gentamicin into the tarsocrural joint of horses, to determine pharmacokinetics of gentamicin in synovial fluid of the tarsocrural joint during continuous infusion, and to evaluate effects of continuous infusion of gentamicin on characteristics of the synovial fluid. ANIMALS: 12 healthy adult horses. PROCEDURE: An infusion catheter consisting of flow control tubing connected to a balloon infuser was used. Gentamicin solution (100 mg/ml) was infused in the right tarsocrural joint and balanced electrolyte solution was infused in the left tarsocrural joint for 5 days. Synovial fluid and serum gentamicin concentrations were measured by use of a fluorescence polarization immunoassay. RESULTS: 17 of the 24 (71%) infusion catheters initially placed functioned without complications for the entire 5-day infusion period. Median gentamicin concentration in synovial fluid from treated joints during the 5-day infusion period ranged from 2875 to 982 microg/ml. Median serum gentamicin concentration during this period ranged from 2.31 to 2.59 microg/ml. Mean (+/- SD) elimination half-life and total clearance of gentamicin from the synovial fluid were 6.25+/-1.01 hours and 1.52+/-0.96 ml/min, respectively. CONCLUSIONS AND CLINICAL RELEVANCE: An infusion catheter can be used for continuous infusion of gentamicin into the tarsocrural joints of horses for up to 5 days. At a gentamicin dosage of 0.17+/-0.02 mg/kg/h, continuous intra-articular infusion results in synovial fluid gentamicin concentrations greater than 100 times the minimal inhibitory concentration reported for common equine pathogens.

Diagnosis of sporotrichosis in a donkey using direct fluorescein-labeled antibody testing.

A 4-year-old female donkey residing in an open field in Indiana was admitted for evaluation of facial lesions of 2 years duration. Cytologic and histologic examination of exudate and tissue from the lesions revealed a pyogranulomatous inflammatory reaction with numerous yeasts. Sporothrix schenckii was suspected to be the infectious agent; however, multiple culture attempts did not provide positive identification of the organism. Serologic examination supported infection with S. schenckii. A specific direct immunofluorescent antibody test performed on paraffin-embedded tissue sections confirmed the organism as S. schenckii. Clinical signs resolved after appropriate iodide therapy.

Treatment of granular cell tumor via complete right lung resection in a horse.

A 7-year-old warmblood mare was referred because of a respiratory tract disorder; pulmonary granular cell tumor was diagnosed. Pulmonary granular cell tumor is a locally invasive but rare type of tumor with low metastatic potential. The entire right lung was resected to ensure removal of all neoplastic tissue. The horse recovered well and has minimal difficulties functioning with one lung. Most of these tumors are diagnosed during postmortem examination. To our knowledge, this is the first report of pulmonary granular cell tumor treated by complete lung resection in a horse.

The surgical anatomy of the stifle joint in sheep.

OBJECTIVE: To provide a detailed description of the surgical anatomy of the stifle joint in sheep. STUDY DESIGN: The results from analysis of cadaveric dissections (14 stifle joints) and stifle radiographs (8 sets of mediolateral and craniocaudal radiographs) are presented. ANIMALS: Skeletally mature ewes of mixed breeds. CONCLUSIONS: Although the anatomy of the ovine stifle joint is similar to that of the human knee joint, a number of unique features were identified. These included the presence of the tendon of the m. extensor digitorum longus on the craniolateral aspect of the stifle joint, the absence of a cranial meniscofemoral ligament (ligament of Humphrey) in the caudal joint space, and attachment of the patellar tendon to the cranial pole of the patella (rather than to the distal pole, as in humans). The implications of these differences are discussed with reference to the suitability of the ovine stifle as a surgical model for the human knee joint.

Digital perfusion, evaluated scintigraphically, and hoof wall growth in horses with chronic laminitis treated with egg bar-heart bar shoeing and coronary grooving.

Nuclear scintigraphy was used to assess digital perfusion before and after treatment in 10 horses with clinical and radiographic evidence of chronic laminitis. Horses were evaluated for lameness, degree of distal phalanx rotation, and heel-toe hoof wall growth ratio, and randomly divided into two treatment groups. Group 1 horses received only egg bar-heart bar shoeing; Group 2 underwent egg bar-heart bar shoeing and coronary grooving. Horses were re-evaluated for digital perfusion, lameness, degree of distal phalanx rotation, and hoof wall growth at 6 week intervals over the 18 week follow-up period. Prior to treatment, relative scintigraphic activity at the dorsal laminar area was decreased and relative scintigraphic activity at the toe and adjacent solar area was increased. Egg bar-heart bar shoeing was associated with significantly increased dorsal laminar scintigraphic activity and significantly decreased solar scintigraphic activity over the 18 week period. Coronary grooving, in combination with egg bar-heart bar shoeing, resulted in a significantly lower heel-toe hoof wall growth ratio but did not enhance digital perfusion. Seven of 10 (70%) horses were responsive to treatment, defined as an improvement in lameness by at least one grade. Horses that were refractory to treatment had significantly lower dorsal laminar scintigraphic activity and higher palmar coronary scintigraphic activity prior to treatment than horses that responded to treatment. Our results are the first to demonstrate that egg bar-heart bar shoeing is associated with improved dorsal laminar perfusion, and support the use of this technique. In addition, we found that pre-treatment nuclear scintigraphy was predictive of clinical outcome in horses with chronic laminitis treated with corrective shoeing.

Decision making in ruminant orthopedics.

Decision making in ruminant orthopedics is determined by many factors, the most of important of which is age, size, and value of the patient, the nature of the injury, the prognosis for effective treatment and satisfactory healing, the intentions of the client, and the experiences of the veterinarian. Ruminant orthopedics currently is expanding to include the treatment of llamas and small ruminants as companion animals in addition to the treatment of valuable livestock. The future promises increasing sophistication in treatments and an ever higher quality of patient care.

Treatment of fractures of the tibia and radius-ulna by external coaptation.

External coaptation of radial-ulnar and tibial fractures with casts or modified Thomas splint-cast combinations is a useful treatment. The economics of therapy make this method of treatment feasible for commercial animals. Current estimates for the cost of treatment of tibial fractures with Thomas splint-cast combinations are $225.00 for calves and $410.00 for cattle if the metal splints are reused. Casts have similar costs. The availability of external coaptation techniques to all veterinarians and the success of treatment make external coaptation a good method for the treatment of many tibial and radial-ulnar fractures in cattle.