James L. Tomlinson

Long-term Outcome for Large Meniscal Defects Treated With Small Intestinal Submucosa in a Dog Model

Background Large meniscal defects are a common problem for which current treatment options are limited. Hypothesis Treatment of posterior medial meniscal defects in dogs with small intestinal submucosa is superior to partial meniscectomy in terms of clinical limb function, chondroprotection, and amount and type of new tissue in the defect. Study Design Controlled laboratory study. Methods A total of 51 mongrel dogs underwent medial arthrotomy with creation of standardized meniscal defects. The dogs were divided into groups based on defect treatment: small intestinal submucosa meniscal implant (n = 29) or meniscectomy (n = 22). The dogs were assessed for lameness by subjective scoring after surgery and sacrificed at 3, 6, or 12 months and assessed for articular cartilage damage, gross and histologic appearance of the operated meniscus, amount of new tissue in the defect, equilibrium compressive modulus of meniscal tissue, and relative compressive stiffness of articular cartilage. Results Dogs in the meniscectomy groups were significantly (P <. 001) more lame than dogs treated with small intestinal submucosa. Joints treated with small intestinal submucosa had significantly (P <. 001) less articular cartilage damage, based on india ink staining, than did those treated with meniscectomy. Menisci receiving small intestinal submucosa had more tissue filling in the defects than did menisci receiving no implants, and this new tissue was more mature and meniscus-like and better integrated with remaining meniscus. Conclusion Small intestinal submucosa scaffolds placed in large meniscal defects resulted in production of meniscus-like replacement tissue, which was consistently superior to meniscectomy in amount, type, and integration of new tissue; chondroprotection; and limb function in the long term. Clinical Relevance Small intestinal submucosa implants might be useful for treatment of large posterior vascular meniscal defects in humans.

Use of radiographic measures and three-dimensional computed tomographic imaging in surgical correction of an antebrachial deformity in a dog

CASE DESCRIPTION A 1-year-old 7.4-kg (16.3-lb) castrated male mixed-breed dog was evaluated because of intermittent lameness and an antebrachial angular limb deformity. CLINICAL FINDINGS The left forelimb had gross antebrachial external rotation (approx 90 degrees ) and marked procurvatum. Radiography revealed a severe partially compensated biapical antebrachial angular limb deformity. Measurements of medial proximal radial angle (MPRA) and lateral distal radial angle (LDRA) were obtained from orthogonal radiographs of the proximal and distal segments of the radius, respectively. Elbow joint-to-carpus translation was quantified. Deformities were localized and quantified by the center of rotation of angulation (CORA) method. Computed tomographic 3-dimensional image reconstructions of the antebrachium and carpus were completed to create 3 life-size stereolithographic models. TREATMENT AND OUTCOME 2 closing wedge radial osteotomies were performed at the level of the CORAs and stabilized with bone plates and screws. RESULTS Frontal and sagittal plane alignments were corrected to 8 degrees and 15 degrees , respectively (reference limits, 0 degrees to 8 degrees and 8 degrees to 35 degrees , respectively). The MPRA was corrected from 55 degrees to 68 degrees , and LDRA was corrected from 32 degrees to 76 degrees (values considered normal are approx 85 degrees and 87 degrees , respectively). Elbow joint-to-carpus translation was improved by 42.5%. After 8 weeks, radiography revealed bone union. Owners considered the outcome acceptable, on the basis of limb appearance and lack of lameness at 1 year after surgery. CONCLUSIONS AND CLINICAL RELEVANCE A segmental radiographic planning technique combined with the CORA method, computed tomography, and stereolithography may be useful in the characterization of and planning corrective surgery for forelimb deformities in dogs.

Fibrochondrogenesis of Free Intraarticular Small Intestinal Submucosa Scaffolds

Naturally occurring biomaterials, such as small intestine submucosa (SIS), are attractive as potential scaffolds for engineering various tissue types. The aim of this study was to determine whether acellular SIS scaffolds can support cell attachment and ingrowth in a diarthroadial joint without significant intraarticular hemorrhage. Disks of porcine SIS were arthoscopically implanted freely within a randomized knee joint of 21 dogs and harvested 1, 2, 3, and 6 weeks postoperatively. Harvested disks were assessed for gross and histologic appearance, cellular infiltration, and immunoreactivity of collagenase and collagen types I and II. Knee synovium and synovial fluid were also evaluated. All disks were thickened and opacified at harvest. Eleven disks (52%) had adhered to intraarticular tissues and cellular infiltration into the disks was positively correlated with tissue adherence. Further, tissue adherence was positively correlated with duration of intraarticular implantation. Five disks (24%) contained focal areas of homogeneous extracellular matrix. A trend toward more collagenase immunoreactivity was noted in the 3-week disks. Collagen type I was present in remaining SIS and extracellular matrix associated with infiltrated cells. Placed freely within a joint, acellular SIS disks underwent cellular and extracellular matrix modification resulting in fibrocartilage-like tissue. Utilization of SIS as a scaffold for intraarticular tissue-engineering applications is supported as cytoconductivity, appropriate residence time, and absence of untoward effects of implantation are desirable criteria for a tissue-engineering biomaterial.

Evaluation of closed reduction and screw fixation in lag fashion of sacroiliac fracture-luxations.

OBJECTIVE To evaluate outcome by radiographic assessment after closed reduction and percutaneous screw fixation in lag fashion of sacroiliac fracture-luxations in dogs. STUDY DESIGN Retrospective study. ANIMALS Dogs (n=24) with sacroiliac fracture-luxations. METHODS Medical records (1999-2006) and radiographs of 24 dogs (29 fracture-luxations) that had stabilization of sacroiliac fracture-luxation by fluoroscopic-guided closed reduction and percutaneous screw fixation in lag fashion were reviewed. Signalment, body weight, number, and location of all concurrent injuries and implants used for repair were recorded. Radiographs were used to evaluate the accuracy of screw placement in the sacral body, screw depth/sacral width ratio, reduction of the sacroiliac joint, pelvic canal diameter, and hemipelvic canal width. Radiographic re-examination (range, 4 to >8 weeks postoperatively) was available for evaluation. RESULTS Mean screw depth/sacral width ratio on immediate postoperative and re-examination radiographs was 64% and 61%, respectively. Mean percentage reduction of the sacroiliac joint on immediate postoperative and re-examination radiographs were 91% and 87%, respectively. Pelvic canal diameter ratio demonstrated successful restoration of the pelvic canal. Hemipelvic canal width ratio documented successful closed reduction repair independent of concurrent pelvic injuries. CONCLUSION Successful repair of sacroiliac fracture-luxations, determined by radiographic assessment, can be achieved by fluoroscopic-guided closed reduction and percutaneous screw fixation in lag fashion. CLINICAL RELEVANCE Fluoroscopic-guided closed reduction and percutaneous screw fixation in lag fashion of sacroiliac fracture-luxations is a minimally invasive technique that restores and maintains pelvic canal dimensions and should be considered as an alternative to open reduction or nonsurgical management of sacroiliac fracture-luxations.

The effects of TIMP-1 and -2 on canine chondrocytes cultured in three-dimensional agarose culture system

OBJECTIVE To investigate the effects of tissue inhibitor of metalloproteinase (TIMP)-1 and -2 on chondrocytes cultured with or without interleukin (IL)-1 beta. DESIGN Canine articular chondrocytes were cultured in three-dimensional (3-D) agarose constructs. Cells were distributed into each of the two groups, those without IL-1 beta and those with IL-1 beta added to the liquid media. Each group was subdivided into three groups, based on the presence of TIMP-1 or -2. IL-1 beta and TIMPs were added to liquid media bathing the 3-D constructs beginning on day 3. The liquid media and the 3-D constructs were collected on days 9, 15, and 24, and analyzed histologically, biochemically, and immunohistochemically. RESULTS Addition of TIMP-1 or -2 resulted in decreases in matrix metalloproteinase (MMP)-3 concentrations of 37 and 41%, and MMP-1 immunoreactivity of 32 and 36%, respectively, compared with the IL-1 beta group, on day 9. Chondrocytes in groups without IL-1 beta maintained viability and produced abundant extracellular matrix (ECM). Chondrocytes in IL-1 beta groups appeared less viable and produced less ECM compared with those without IL-1 beta. Glycosaminoglycan (GAG) concentrations in 3-D constructs (GAG/weight) were significantly (P<0.001) higher in groups without IL-1 beta than in those with IL-1 beta, on days 15 and 24. CONCLUSIONS The addition of TIMP was not detrimental to chondrocytes, as used in this study. Despite evidence of decreased MMP levels, TIMPs did not prevent IL-1 beta-associated changes in cellular or ECM characteristics. Further study is necessary before clinically relevant conclusions can be drawn regarding the use of TIMPs in the treatment of osteoarthritis.

Scapular fractures in dogs: epidemiology, classification, and concurrent injuries in 105 cases (1988-1994).

A retrospective study of canine scapular fractures diagnosed and treated from 1988 through 1994 at four veterinary teaching hospitals was performed. Dogs (n = 105) with 109 scapular fractures were included. Most scapular fractures occurred in young (i.e., less than four years of age), male, medium- to large-breed (i.e., greater than 10 kg) dogs as the result of vehicular trauma. Concurrent injuries (primarily thoracic trauma) occurred in approximately 70% of cases. In-house follow-up evaluations were considered adequate in only 17% of the cases. A classification system that includes biomechanical principles for categorization is described to avoid discrepancies between various traditional classification systems.

Acetabular Ventroversion with Double Pelvic Osteotomy Versus Triple Pelvic Osteotomy: A Cadaveric Study in Dogs

OBJECTIVE To determine which of 3 different plate angles (20°, 25°, 30°) used in double pelvic osteotomy (DPO) would result in the most similar acetabular angle (AA) achieved with a 20° triple pelvic osteotomy (TPO) technique in dogs. STUDY DESIGN Experimental anatomic study. ANIMALS Cadaveric canine pelves (n = 8). METHODS Transverse plane computed tomographic images of cadaveric pelves with intact sacroiliac joints, mounted in a custom jig, were made (baseline) and again after DPO (20°, 25°, 30°) and TPO (20°) and pelvic angles measured in 6 transverse planes. Pelvic angles of the 3 DPO techniques were compared with TPO using concordance correlation to determine which DPO angle resulted in an acetabular ventroversion angle closest to TPO. RESULTS Mean ± SD AAs were 32.89 ± 2.23 (baseline), 47.39 ± 4.39 (20° DPO), 51.43 ± 5.06 (25° DPO), 54.75 ± 4.38 (30° DPO), and 50.20 ± 5.76 (20° TPO). Concordance correlations for the AA compared with 20° TPO were 0.027 (baseline), 0.721 (20° DPO), 0.902 (25° DPO), and 0.593 (30° DPO). A concordance correlation of ≥ 0.8 indicates good correlation. CONCLUSIONS A 25° DPO is most similar in acetabular ventroversion to 20° TPO (concordance correlation, 0.902).

Measurement of Femoral and Tibial Joint Reference Angles and Pelvic Limb Alignment in Cats

Objective To report pelvic limb joint reference angles, limb alignment, and mechanical axis deviation for the feline pelvic limb. Study Design Cadaveric radiographic anatomic study. Animals Skeletally mature, mixed breed cats (n = 50). Methods Extended pelvic limb radiography was performed and images analyzed to determine femoral anatomic joint reference angles, femoral and tibial mechanical joint reference angles, tibiofemoral angle, metatarsotibial angle, mechanical axis-femur and mechanical axis-metatarsus angles, and mechanical axis deviation of the stifle and tarsus. Mean ± SD and 95% confidence intervals (95% CI) were calculated. Results Mean ± SD angles and 95% CI were: anatomic lateral proximal femoral (103.9° ± 3.8°; 103.1° − 104.6°), anatomic lateral distal femoral (93.8° ± 2.5°; 93.3° − 94.3°), mechanical lateral proximal femoral (100.5° ± 3.7°; 99.8° − 101.2°), mechanical lateral distal femoral (97.2° ± 2.2°; 96.7° − 97.6°), mechanical medial proximal tibial (88.0° ± 3.2°; 87.3° − 88.6°), mechanical medial distal tibial (107.6° ± 4.8°; 106.6° − 108.5°), mechanical tibiofemoral (7.4° varus ± 2.5°; 6.9° − 7.9°), mechanical metatarsotibial (6.0° valgus ± 3.5°; 5.3° − 6.7°); mechanical axis-femur (3.2° ± 1.4°; 2.9° − 3.5°) and mechanical axis-metatarsus (2.4° ± 2.0°; 1.7° − 2.1°). Mechanical axis deviation of the stifle and of the tarsus were 2.0% ± 0.9% (95% CI: 1.9–2.2) and 0.8% ± 1.0% (95% CI: 0.7–1.0), respectively. Conclusions Mean pelvic limb joint reference and limb alignment angles can be used for diagnosing angular limb deformities of the feline pelvic limb and for planning corrective osteotomies in affected cats.OBJECTIVE To report pelvic limb joint reference angles, limb alignment, and mechanical axis deviation for the feline pelvic limb. STUDY DESIGN Cadaveric radiographic anatomic study. ANIMALS Skeletally mature, mixed breed cats (n = 50). METHODS Extended pelvic limb radiography was performed and images analyzed to determine femoral anatomic joint reference angles, femoral and tibial mechanical joint reference angles, tibiofemoral angle, metatarsotibial angle, mechanical axis-femur and mechanical axis-metatarsus angles, and mechanical axis deviation of the stifle and tarsus. Mean ± SD and 95% confidence intervals (95% CI) were calculated. RESULTS Mean ± SD angles and 95% CI were: anatomic lateral proximal femoral (103.9° ± 3.8°; 103.1° - 104.6°), anatomic lateral distal femoral (93.8° ± 2.5°; 93.3° - 94.3°), mechanical lateral proximal femoral (100.5° ± 3.7°; 99.8° - 101.2°), mechanical lateral distal femoral (97.2° ± 2.2°; 96.7° - 97.6°), mechanical medial proximal tibial (88.0° ± 3.2°; 87.3° - 88.6°), mechanical medial distal tibial (107.6° ± 4.8°; 106.6° - 108.5°), mechanical tibiofemoral (7.4° varus ± 2.5°; 6.9° - 7.9°), mechanical metatarsotibial (6.0° valgus ± 3.5°; 5.3° - 6.7°); mechanical axis-femur (3.2° ± 1.4°; 2.9° - 3.5°) and mechanical axis-metatarsus (2.4° ± 2.0°; 1.7° - 2.1°). Mechanical axis deviation of the stifle and of the tarsus were 2.0% ± 0.9% (95% CI: 1.9-2.2) and 0.8% ± 1.0% (95% CI: 0.7-1.0), respectively. CONCLUSIONS Mean pelvic limb joint reference and limb alignment angles can be used for diagnosing angular limb deformities of the feline pelvic limb and for planning corrective osteotomies in affected cats.

Distraction osteogenesis for treatment of premature physeal closure and shortening of the third and fourth metatarsals of a dog.

A 4-month-old Siberian husky was presented for a history of lameness of the left hind limb. Physical and radiographic examination revealed a 1-cm shortening of metatarsals III and IV, with subsequent hyperextension of the digits on the left hind paw. A circular external skeletal fixator was used to accomplish distraction osteogenesis in both metatarsals over a period of 15 days. Treatment was successful in restoring appropriate length of the metatarsals and in resolution of the lameness. At 6 and 12 months after surgery, the owner reported that the dog was ambulating normally and had no complications related to the surgery.

Classification of Angular Limb Deformities Affecting the Canine Radius and Ulna Using the Center of Rotation of Angulation Method

OBJECTIVE To classify the type of angular deformity affecting the radius and ulna in canine limbs using the center of rotation of angulation methodology. STUDY DESIGN Retrospective case series. ANIMALS Dogs (n=71) diagnosed with thoracic limb lameness attributable to antebrachial angular limb deformities. METHODS Medical records from 2006-2013 were searched and cases with orthogonal radiographs or computed tomographic scans of the affected antebrachium were included. Classification of the deformity in the frontal plane and the presence of sagittal plane angulation, torsion, and adjacent joint radiographic disease were determined and compared. RESULTS Chondrodystrophic (n=26; 44 limbs) and non-chondrodystrophic (n=45; 62 limbs) dogs were included. Thirty-five uniapical and 71 biapical or multiapical deformities in the frontal plane were identified. The incidence of biapical deformities was statistically higher in chondrodystrophic compared to non-chondrodystrophic dogs (P=.02). When breeds were combined, biapical deformities were associated with a significantly higher incidence of adjacent radiographic joint disease (P=.049), more frequently affecting the elbow (P=.022). Overall, 82% of the 106 limbs had radiographic evidence of either elbow or carpal joint disease at the time of presentation. CONCLUSION Biapical deformities are common in dogs with limb deformities, particularly chondrodystrophic dogs. Radiographic evidence of disease in adjacent joints should be evaluated in patients presenting for antebrachial deformities.