Varus mechanism is associated with high incidence of popliteal artery lesions in multiligament knee injuries.

PURPOSE: This study aims to identify multiple ligament knee injury patterns that possess a high-risk of vascular lesion. METHODS: We retrospectively compared torn ligament patterns and the presence of vascular lesions confirmed by magnetic resonance imaging and computed tomography angiography from 122 consecutive patients with diagnoses of multiple ligament knee injury made at the emergency department between January 2012 and December 2017. Patients were not eligible if they had an ipsilateral lower extremity lesion (dislocations or fractures at another level), initial evaluation at another hospital, or follow-up for less than 12 months. The primary outcomes were the comparison between the imaging findings of torn structures patterns and the presence of a vascular lesion. RESULTS: We identified 48 eligible patients (50 knees) with multiligamentary knee lesions, of whom eight had popliteal artery damage, yielding an incidence of 16%. Our clinical examination detected six of these patients that were classified, according to the Schenck system, as KD-IIIL (6 knees) and KD-IIIM (2 knees). The odds of having a popliteal artery injury is 4.69 to 1 with a KD-IIIL injury that with any other type of injury on that classification (95% CI 0.960-22.98). CONCLUSIONS: This data suggests that varus forces causing enough energy to produce a KD-IIIL lesion possess a higher popliteal artery injury risk, making recommendable a thorough examination of the vascular integrity when diagnosing a KD-IIIL lesion.

Specific, Sensitive, and Stable Reporting of Human Mesenchymal Stromal Cell Chondrogenesis.

IMPACT STATEMENT: The promoter characterized in this study has been made accessible as a resource for the skeletal tissue engineering and regenerative medicine community. When combined with suitable reporter vectors, the resulting tools can be used for noninvasive and/or high-throughput screening of test conditions for stimulating chondrogenesis by candidate stem/progenitor cells. As demonstrated in this study, they can also be used with small animal imaging platforms to monitor the chondrogenic activity of implanted progenitors within orthotopic models of bone and cartilage repair.

No association between positive intraoperative allograft cultures and infection rates after reconstructive knee ligament surgery.

BACKGROUND: Several reports of severe infections associated with allograft tissue in knee reconstructive surgery have led many surgeons to consider routine intraoperative culture of allograft tissue before implantation. Thus, the purpose of this study was to determine the prevalence of positive soft tissue allograft cultures in reconstructive knee surgery, and evaluate its association with surgical site infection. METHODS: Retrospective study of 202 patients who underwent knee reconstructive ligament surgeries, including revisions, between January 2013 and July 2017. Intraoperative culture results were obtained and the report of a surgical site infection during follow-up was recorded. Patients without cultures were excluded. A priori power analysis was performed. The association between positive culture results and development of surgical site infection was evaluated using Fisher's Exact test (P < 0.05). RESULTS: A total of 300 allografts were implanted in 202 patients. Mean average follow-up was 32.9 ±â€¯12.5 (range 13 to 57.9) months. Sixteen patients had positive intraoperative allograft cultures (7.9%). The most frequently isolated organism was Bacillus species (six cultures); none of these patients presented with clinical signs of infection. Nine patients developed surgical site infections and were treated with oral antibiotics, and one patient developed septic arthritis that required surgical debridement of the implanted graft; all of these patients had a negative soft tissue allograft culture. No significant association was found between a positive culture and surgical site infection (P = 0.43). CONCLUSION: There was no apparent association between positive intraoperative irradiated soft tissue allograft cultures and surgical site infection in reconstructive knee surgery.

A rabbit model demonstrates the influence of cartilage thickness on intra-articular drug delivery and retention within cartilage.

For evaluation of new approaches to drug delivery into cartilage, the choice of an animal model is critically important. Since cartilage thickness varies with animal size, different levels of drug uptake, transport and retention should be expected. Simple intra-articular injection can require very high drug doses to achieve a concentration gradient high enough for drug diffusion into cartilage. New approaches involve nanoparticle delivery of functionalized drugs directly into cartilage; however, diffusion-binding kinetics proceeds as the square of cartilage thickness. In this study, we demonstrate the necessity of using larger animals for sustained intra-cartilage delivery and retention, exemplified by intra-articular injection of Avidin (drug-carrier) into rabbits and compared to rats in vivo. Penetration and retention of Avidin within cartilage is greatly enhanced by electrostatic interactions. Medial tibial cartilage was the thickest of rabbit cartilages, which generated the longest intra-cartilage half-life of Avidin (τ1/2 = 154 h). In contrast, Avidin half-life in thinner rat cartilage was 5-6 times shorter (τ1/2 ∼ 29 h). While a weak correlation (R(2) = 0.43) was found between Avidin half-lives and rabbit tissue GAG concentrations, this correlation improved dramatically (R(2) = 0.96) when normalized to the square of cartilage thickness, consistent with the importance of cartilage thickness to evaluation of drug delivery and retention.

Electrostatic interactions enable rapid penetration, enhanced uptake and retention of intra-articular injected avidin in rat knee joints.

Intra-articular (i.a.) drug delivery for local treatment of osteoarthritis remains inadequate due to rapid clearance by the vasculature or lymphatics. Local therapy targeting articular cartilage is further complicated by its dense meshwork of collagen and negatively charged proteoglycans, which can prevent even nano-sized solutes from entering. In a previous in vitro study, we showed that Avidin, due to its size (7 nm diameter) and high positive charge (pI 10.5), penetrated the full thickness of bovine cartilage and was retained for 15 days. With the goal of using Avidin as a nano-carrier for cartilage drug delivery, we investigated its transport properties within rat knee joints. Avidin penetrated the full thickness of articular cartilage within 6 h, with a half-life of 29 h, and stayed inside the joint for 7 days after i.a. injection. The highest concentration of Avidin was found in cartilage, the least in patellar tendon and none in the femoral bone; in contrast, negligible Neutravidin (neutral counterpart of Avidin) was present in cartilage after 24 h. A positive correlation between tissue sGAG content and Avidin uptake (R(2) = 0.83) confirmed the effects of electrostatic interactions. Avidin doses up to at least 1 µM did not affect bovine cartilage explant cell viability, matrix catabolism or biosynthesis.

Anterior cruciate ligament regeneration using mesenchymal stem cells and collagen type I scaffold in a rabbit model.

PURPOSE: The objective of this study was to determine whether using mesenchymal stem cells (MSC) seeded in a collagen type I scaffold would be sufficient to regenerate the torn anterior cruciate ligament (ACL). METHODS: Anterior cruciate ligament transection was performed on both knees in 10 New Zealand rabbits and then repaired with as follows: suture alone (suture-treated group, n = 6), suture associated with collagen type I scaffold (collagen type I scaffold-treated group, n = 8) or suture associated with autologous MSC seeded on collagen type I scaffold (MSC/collagen type I scaffold-treated group, n = 6). At 12-week post-intervention, the animals were killed and the ACLs were characterised macroscopically and histologically. Data of the 3 groups were against normal ACL (normal group, n = 10). RESULTS: Macroscopic observation found that in MSC/collagen type I scaffold group, 33% of specimens showed a complete ACL regeneration, with a tissue similar to the normal ACL. Regeneration was not observed in the group treated with suture alone or associated with collagen type I scaffold without cells. In the latter, only a reparative attempt at the ends was observed. Histological analysis of the regenerated ACL showed a tissue with organised collagen and peripheric vessels. CONCLUSIONS: These results provide evidence that the use of MSC seeded in a collagen type I scaffold in the treatment of ACL injuries is associated with an enhancement of ligament regeneration. This MSC-based technique is a potentially attractive tool for improving the treatment of ACL ruptures.

[Long-term results of repair versus replacement for degenerative mitral valve regurgitation]. / Resultados alejados de la reparación versus reemplazo en insuficiencia mitral degenerativa.

BACKGROUND: Mitral valve repair is considered better than mitral valve replacement for degenerative mitral regurgitation. AIM: To evaluate late clinical results of mitral valve repair as compared to mitral valve replacement in patients with degenerative mitral regurgitation. PATIENTS AND METHODS: All patients subjected to open heart surgery for degenerative mitral regurgitation between 1990 and 2002 were assessed for surgical mortality, late cardiac and overall mortality, reoperation, readmission to hospital, functional capacity and anticoagulant therapy. Eighty eight patients (48 males) had mitral valve repair and 28 (19 males) had mitral valve replacement (23 with a mechanical prosthesis). Mean age was 59.9 +/- 14.8 (SD) and 61.3 +/- 14.6 years, respectively. Sixty three percent of patients with repair and 50% of those with valve replacement were in functional class III or IV before surgery. RESULTS: Operative mortality was 2.3% for mitral valve repair and 3.6% for mitral valve replacement (NS). Also, there was no statistical difference in the need of reoperation during the follow-up period between both procedures (2.3% and 0%, respectively). Ninety four percent of the replacement patients but only 26% of the repair patients were in anticoagulant therapy at the end of the follow-up period (p < 0.001). Ten years survival rates were 82 +/- 6% for mitral valve repair and 54 +/- 11% for replacement. The corresponding cardiac related survival rates were 89 +/- 6% and 79 +/- 10%. At the end of follow-up, all surviving patients were in functional class I or II. Ten years freedom from cardiac event rates (death, cardiac related rehospitalization and reoperation) were 90 +/- 3% for mitral valve repair and 84 +/- 6% for replacement. CONCLUSION: Repair of the mitral valve offers a better overall survival and a better chance of freedom from cardiac events as well as need for anticoagulation 10 years after surgery.

[Valve repair surgery for incompetent bicuspid aortic valves]. / Ciruguía reparadora de la válvula aórtica bicúspide insuficiente.

BACKGROUND: Surgical valve repair is a good alternative for correction of incompetent bicuspid aortic valve. AIM: To report the early and late surgical, clinical and ecochardiographic results of surgical repair of incompetent bicuspid aortic valves. PATIENTS AND METHODS: Retrospective review of medical records of 18 patients aged 19 to 61 years, with incompetent bicuspid aortic valve in whom a valve repair was performed. Four patients had infectious endocarditis and 17 were in functional class I or II. Follow up ranged from 3 to 113 months after surgery. RESULTS: A triangular resection of the prolapsing larger cusp, which included the middle raphe, was performed in 17 cases; in 13 of these, a complementary subcommisural annuloplasty was performed. In the remaining case, with a perforation of the non-coronary cusp, a pericardial patch was implanted; this procedure was also performed in 2 other cases. In 3 cases large vegetations were removed. Postoperative transesophageal echocardiography showed no regurgitation in 11 patients (62%) and mild regurgitation in 7 (38%). There was no operative morbidity or mortality. There were no deaths during the follow-up period. In 3 patients (17%) the aortic valve was replaced with a mechanical prosthesis, 8 to 108 months after the first operation. Reoperation was not needed in 93%+/-6,4% at 1 year and 85%+/-9,5% at 5 years, these patients were all in functional class I at the end of the follow-up period. 60% had no aortic regurgitation, 20% had mild and 20% moderate aortic regurgitation on echocardiographic examination. A significant reduction of the diastolic diameter of the left ventricle was observed, but there were no significant changes in systolic diameter or shortening fraction. CONCLUSIONS: Surgical repair of incompetent bicuspid aortic valves has low operative morbidity and mortality and has a low risk of reoperation.