Comparison of meniscal fibrochondrocyte and synoviocyte bioscaffolds toward meniscal tissue engineering in the dog

Tissue engineering is a promising field of study toward curing the meniscal deficient stifle; however the ideal cell type for this task is not known. We describe here the extraction of synoviocytes and meniscal fibrochondrocytes from arthroscopic debris from six dogs, which were cultured as tensioned bioscaffolds to synthesize meniscal-like fibrocartilage sheets. Despite the diseased status of the original tissues, synoviocytes and meniscal fibrochondrocytes had high viability at the time of removal from the joint. Glycosaminoglycan and collagen content of bioscaffolds did not differ. Meniscal fibrochondrocyte bioscaffolds contained more type II collagen, but collagen deposition was disorganized, with only 30–40% of cells viable. The collagen of synoviocyte bioscaffolds was organized into sheets and bands and 80–90% of cells were viable. Autologous, diseased meniscal fibrochondrocytes and synoviocytes are plausible cell sources for future meniscal tissue engineering research, however cell viability of meniscal fibrochondrocytes in the tensioned bioscaffolds was low.     

Arthroscopic treatment of meniscal cysts in the horse

Reasons for performing study: To describe the clinical symptoms, treatment, and outcome of meniscal cysts in horses. These structures have not been previously described in the literature as a potential cause of lameness in the horse. Hypothesis: Meniscal cysts are an uncommon condition of the femorotibial joint but can be a significant cause of lameness. Symptoms can be resolved by arthroscopic excision. Methods: Records of horses diagnosed with meniscal cysts and treated by cyst excision and meniscal debridement at 2 surgical practices were reviewed. Clinical outcome was determined by repeat veterinary examination and contact with owner. Results: Seven cases of meniscal cyst were treated with arthroscopic cyst excision and meniscal debridement. Five of 7 horses had lameness attributable to femorotibial joint pathology, while the remaining 2 horses had meniscal cysts found incidentally during diagnostic arthroscopy for the treatment of osteochondritis dissecans of the lateral trochlear ridge of the femur. Five of 6 horses with long‐term follow‐up were sound and a 7th horse was improved 11 months after surgery. Conclusions and potential relevance: Meniscal cysts, while uncommon, can be associated with progressive lameness in the horse. Surgical excision of the cysts results in resolution or improvement of symptoms, without evidence of recurrence on follow‐up examination.     

Culture of canine synoviocytes on porcine intestinal submucosa scaffolds as a strategy for meniscal tissue engineering for treatment of meniscal injury in dogs

Meniscal injury is a common cause of canine lameness. Tissue engineered bioscaffolds may be a treatment option for dogs suffering from meniscal damage. The aim of this study was to compare in vitro meniscal-like matrix formation and biomechanical properties of porcine intestinal submucosa sheets (SIS), used in canine meniscal regenerative medicine, to synoviocyte-seeded SIS bioscaffold (SSB), cultured with fetal bovine serum (SSBfbs) or chondrogenic growth factors (SSBgf). Synoviocytes from nine dogs were seeded on SIS and cultured for 30 days with 17.7% fetal bovine serum or recombinant chondrogenic growth factors (IGF-1, TGFβ1 and bFGF). The effect on fibrochondrogenesis was determined by comparing mRNA expression of collagen types Iα and IIα, aggrecan, and Sry-type homeobox protein-9 (SOX9) as well as protein expression of collagens I and II, glycosaminoglycan (GAG), and hydroxyproline.The effect of synoviocyte seeding and culture conditions on biochemical properties was determined by measuring peak load, tensile stiffness, resilience, and toughness of bioscaffolds. Pre-culture SIS contained 13.6% collagen and 2.9% double-stranded DNA. Chondrogenic growth factor treatment significantly increased SOX9, collagens I and IIα, aggrecan gene expression (P < 0.05), and histological deposition of fibrocartilage extracellular matrix (GAG and collagen II). Culture with synoviocytes increased SIS tensile peak load at failure, resilience, and toughness of bioscaffolds (P < 0.05). In conclusion, culturing SIS with synoviocytes prior to implantation might provide biomechanical benefits, and chondrogenic growth factor treatment of cultured synoviocytes improves in vitro axial meniscal matrix formation.     

Effect of meniscal release on rate of subsequent meniscal tears and owner-assessed outcome in dogs with cruciate disease treated with tibial plateau leveling osteotomy

OBJECTIVE: To determine and compare rates of meniscal tears after tibial plateau leveling osteotomy (TPLO) among 3 groups of dogs based on treatment method: arthrotomy with meniscal release (openR), arthrotomy without meniscal release (openNR), arthroscopy without meniscal release (scopeNR), and compare long term owner-assessed outcomes for the same groups. STUDY DESIGN: Retrospective cohort study. SAMPLE POPULATION: Stifles (n=254) of dogs that had TPLO. METHODS: The three groups were compared for significant (P<.05) differences in rate of subsequent tears using a chi(2) test. Odds ratios for likelihood of subsequent meniscal tears were determined. Data for signalment, outcome, time to peak function, and time to subsequent tear were compared for significant differences using ANOVA, t-test, or rank sum test. RESULTS: Subsequent meniscal tears were diagnosed in 16 cases (6.3%). Of dogs with subsequent meniscal tears, 9 had openNR, 4 had openR, and 3 had scopeNR; the proportion of subsequent meniscal tears was significantly different (P=.035) among groups. Odds ratio indicated that subsequent meniscal tear was 3.8 times more likely to occur for openNR than openR or scopeNR. No significant differences among groups were noted for measures of outcome. CONCLUSIONS: Meniscal release did not reduce the rate of subsequent meniscal tears when compared with cases treated arthroscopically or when compared with all cases combined, but may be advantageous when meniscal pathology cannot be comprehensively assessed in the cranial cruciate deficient stifle. Meniscal release had no effects on owner-assessed outcome as determined in this study. CLINICAL RELEVANCE: The low rates of subsequent meniscal tears in conjunction with the relatively high and equivocal levels of owner-assessed outcome and time to peak function for all 3 treatment groups suggest that any of these surgical management strategies can be considered acceptable. We suggest that a meniscal release be performed when complete and thorough exploration of the joint and meniscus cannot be, or are not, performed.     

Radionuclide uptake in experimentally induced meniscal lesions in rabbit knees

Internal derangements in the human knee joint caused by meniscal lesions affecting joint function are known to have influence on local radionuclide uptake (Nicholas & Holder 1980, Mooar et al. 1987). To elucidate the joint reaction to minor meniscal lesions, not interfering with knee joint function, a model involving the avascular central part of the medial meniscus was used. Lesions in this area are known not to heal spontaneously (Heatley 1980, Veth et al. 1983).     

Arthroscopic verification of ultrasonographic diagnosis of meniscal pathology in dogs

OBJECTIVE: To determine the clinical usefulness of ultrasonography for diagnosis of meniscal pathology in dogs. STUDY DESIGN: Double-blind prospective study. ANIMALS: Dogs (n=10) with lameness localized to the stifle. MATERIALS AND METHODS: Sonographic examination of each affected stifle was performed by 1 ultrasonographer unaware of specific historical and clinical data for the dog. Sonographic findings were recorded, but not reviewed until study completion. Arthroscopic examination of the affected stifle was performed within 48 hours of ultrasonography by 1 surgeon unaware of ultrasonographic findings. Arthroscopic findings were recorded, but not reviewed until study completion. Two investigators compared the ultrasonographic and arthroscopic findings at study completion to determine the sensitivity, specificity, positive predictive value, and negative predictive value. RESULTS: Two of the 10 dogs had bilateral stifle evaluation. Twenty-four lateral and medial menisci, with normal and abnormal findings, were examined. The sensitivity and specificity for ultrasonographic diagnosis were 90.0% and 92.9%, respectively; positive and negative predictive values were 90.0% and 92.9%, respectively. CONCLUSIONS: Ultrasonography is highly specific and sensitive for diagnosing bucket handle tears of the medial meniscus in dogs. CLINICAL RELEVANCE: Ultrasonographic evaluation of menisci in dogs is a noninvasive method for accurately and efficiently diagnosing pathology, determining the need for surgical intervention, and providing comprehensive information to clients.     

Minimally invasive synovium harvest for potential use in meniscal tissue engineering

Tissue engineering is being investigated as a means for treating avascular meniscal injury or total meniscal loss in human and veterinary patients. The purpose of this study was to determine if an arthroscopic tissue shaver can be used to collect viable synoviocytes for in vitro culture during therapeutic stifle arthroscopy, with the long term goal of producing autologous meniscal fibrocartilage for meniscal tissue engineering. Synovium was harvested arthroscopically from 13 dogs with naturally occurring cranial cruciate ligament deficiency and obtained from 5 dogs with patellar luxation via arthrotomy. Cells harvested via arthroscopy and arthrotomy were treated with a chondrogenic growth factor protocol and analyzed for meniscal-like matrix constituents including collagens type I, II, and glycosaminoglycans. Arthrotomy and Arthroscopic origin cells formed contracted tissues containing collagen I, II and small amounts of GAG. These surgical methods provide clinically relevant access to synoviocytes for potential use in meniscal tissue engineering.     

Incidence of meniscal injury in cats with cranial cruciate ligament ruptures

This retrospective study evaluated the incidence of meniscal injury in cats with cranial cruciate ligament (CCL) ruptures. Medical records for cats diagnosed with CCL ruptures treated by a lateral fabellotibial suture (LFS) were reviewed for signalment, history, physical examination and surgical findings. Ninety-five cats (98 stifles) met the inclusion criteria. The incidence of meniscal injuries in feline CCL deficient stifles was 67%. Isolated medial meniscal injuries were found in 55 stifles (56%), isolated lateral meniscal injuries were found in 5 stifles (5%), and lateral and medial meniscal injuries were found in 6 stifles (6%). There was no correlation between the presence of a meniscal injury and age, breed, sex, weight, duration of lameness, presence of concurrent medial patellar luxation, degree of degenerative joint disease, or presenting side of lameness. Given the high rate of meniscal pathology in cats with CCL ruptures, exploratory surgery for meniscal assessment and concurrent stifle stabilization should be considered in feline patients.     

Ⅰ型胶原涂层聚己内酯(PCL)半月板组织工程支架的细胞亲和性

通过3D生物打印机制备聚己内酯(PCL)组织工程半月板支架,评价其生物力学特性进而筛选出具有最优力学性能的支架,而后检测支架的理化特性并在支架表面涂覆Ⅰ型胶原蛋白改善其细胞亲和性。结果显示,打印支架孔隙率分别为(61.96±0.66)%,(48.65±0.94)%和(31.76±1.50)%,孔隙率为(61.96±0.66)%的支架具有最高压缩模量,支架吸水率与支架体外降解率在第4,8,12周分别为(8.95±0.08)%,(9.24±0.08)%,(9.52±0.02)%和(0.86±0.05)%,(1.29±0.02)%,(1.56±0.13)%,扫描电镜观察计算发现支架平均孔径为500μm左右;通过细胞初始黏附试验和扫描电镜观察发现表面涂覆Ⅰ型胶原蛋白的支架其细胞黏附数明显多于未涂覆的支架;细胞增殖试验表明细胞可很好的在支架上生长增殖且细胞在表面涂覆有Ⅰ型胶原蛋白的支架上增殖性能更好。本试验初步证明,通过3D打印技术构建的PCL组织工程半月板支架经Ⅰ型胶原表面改性后其细胞亲和性得到改善。     

Evaluation of small-intestinal submucosa implants for repair of meniscal defects in dogs

OBJECTIVE: To assess the effects of porcine small intestinal submucosa (SIS) implants on the healing of meniscal lesions in dogs. ANIMALS: 16 adult Greyhounds of both sexes. PROCEDURE: Unilateral osteotomy was performed at time 0 to disrupt the medial collateral ligament attachment, and two (1 cranial and 1 caudal) 4-mm circular defects were created in the avascular portion of the medial meniscus. One defect was filled with an SIS graft, and the other defect remained empty (control). Three months later, the identical procedure was performed on the contralateral limb. Three months after the second surgery, dogs were euthanatized, and meniscal tissue specimens from both stifle joints were collected for gross, histologic, biomechanical, and biochemical evaluations. RESULTS: Regenerative tissue was evident in 4 (2 SIS-implanted and 2 control) of 16 defects examined histologically. In 3 defects, this thin bridge of tissue was composed of immature haphazardly arranged fibrous connective tissue with a relatively uniform distribution of fibroblasts. Aggregate modulus, Poisson ratio, permeability, and shear modulus were not significantly different between control and SIS-implanted defects either 3 or 6 months after surgery. Hydroxyproline content also did not differ between SIS-implanted and control defects at 3 or 6 months. CONCLUSIONS AND CLINICAL RELEVANCE: Implantation of porcine SIS into experimentally induced meniscal lesions in dogs did not promote tissue regeneration.     

Diagnosis and treatment of ligamentous and meniscal injuries in the equine stifle.

The accuracy of the diagnosis of ligamentous and meniscal injuries in the equine stifle has improved significantly in the last 20 years.There are, however, significant limitations in the diagnosis of stifle injuries because of the size and anatomy of the equine stifle. Treatment of soft tissue injuries to the equine stifle has been empirical,with only a few large case studies for specific conditions of stifle ligaments and menisci and only retrospective case studies of the outcome of treatment. This article describes the diagnosis and treatment of ligamentous and meniscal injuries in the equine stifle using information from the author's own experience and from reports in the scientific literature.     

Risk factors for medial meniscal injury in association with cranial cruciate ligament rupture

Objectives : To determine the significant risk factors for medial meniscal injury in naturally occurring cranial cruciate ligament rupture and to quantify the risk using multivariate analysis. Methods : A retrospective case control study was performed of dogs that had undergone surgery for cranial cruciate ligament rupture. Data recorded included patient signalment (age, breed and sex), the duration of the lameness, the extent of the cranial cruciate ligament rupture (complete or partial) and the condition of the medial meniscus. Logistic regression was used to analyse the relationship between these variables and tears in the medial meniscus. Results : One hundred and sixty-one of 443 stifles (36·3%) in 366 dogs had a medial meniscal tear. The risk of a medial meniscal tear was increased by 12·9 times in association with complete cranial cruciate ligament rupture (OR 12·9; 95% CI 6·8 to 24·2), by approximately 2·6% for each additional week of lameness (OR 1·026; 95% CI 1·009 to 1·043) and by approximately 1·4% for each additional kilogram of bodyweight (OR 1·014; 95% CI 1·000 to 1·028). Golden retrievers and Rottweilers were at increased risk and West Highland white terriers were at reduced risk of medial meniscal tears compared with Labrador retrievers. Clinical Significance : To minimise the risk of medial meniscal tears, surgical stabilisation should not be unnecessarily delayed.     

Effect of medial meniscal release on tibial translation after tibial plateau leveling osteotomy

OBJECTIVE: To evaluate the biomechanical effects of medial meniscal release (MMR) and medial, caudal pole hemimeniscectomy (MCH) on joint stability in the cranial cruciate ligament (CCL)-deficient canine stifle before and after tibial plateau leveling osteotomy (TPLO). STUDY DESIGN: Experimental study. ANIMALS: Thirty-one dogs. METHODS: In experiment 1, 16 pairs of normal hindlimbs randomly assigned to an intact or transected CCL group were studied to determine the magnitude of tibial translation after MMR and MCH under 20% body weight load using radiographic imaging of radio-opaque markers. In experiment 2, 15 pairs of CCL-deficient hindlimbs were randomly assigned to a TPLO or sham TPLO group. The remainder of the experiment was performed as described for experiment 1. The effect of CCL transection, MMR, MCH and TPLO were analyzed using 2-way repeated measures ANOVA; P<.05 was considered significant. RESULTS: We found a greater effect of MMR on tibial translation in transected CCL stifles than in intact stifles (P=.0016). We found no further effect of MCH after MMR (P>.05). We found a greater effect of MMR in sham TPLO than TPLO stifles (P=.0013) but no further effect of MCH after MMR (P>.05). CONCLUSIONS: By resisting tibial translation the medial meniscus might be at greater risk of tearing in CCL-deficient stifles. TPLO may spare the medial meniscus by neutralizing the tibial thrust and eliminating the wedge effect of the medial meniscus. CLINICAL RELEVANCE: MMR may not be indicated in the CCL-deficient stifle stabilized by TPLO.