Luis López-Durán

Chitosan scaffolds for osteochondral tissue regeneration

A variety of biomaterials have been introduced as potential substrates for cartilage repair. One such candidate is chitosan, which shares some characteristics with glycosaminoglycan and hyaluronic acid present in articular cartilage. Depending on chitosan source and preparation procedure, variations into its properties can be attained. Thus, the aim of this article is to study and select the most adequate chitosan properties for in vivo osteochondral tissue regeneration. In this work, chitosan molecular weight, deacetylation degree, and calcium content are tested as material variable properties. According to these properties, porous scaffolds were prepared, implanted in rabbit knee osteochondral defects, and evaluated 3 months after surgery. Results show in vitro a considerable influence of the material molecular weight on the scaffold structure. In vivo, different tissue responses were observed depending on the implanted chitosan properties. Some samples showed no material degradation, multiple adverse tissue responses, and no bone/cartilage tissue formation. Other samples showed no adverse responses and bone and cartilage tissue regeneration. The chitosan with intact mineral content (17.9 wt %), lowest molecular weight (11.49 KDa), and lowest deacetylation degree (83%) shows a well structured subchondral bone and noticeable cartilaginous tissue regeneration, being it the best one of those tested for osteochondral defect regeneration.

Early lymphocyte activation in the synovial microenvironment in patients with osteoarthritis: comparison with rheumatoid arthritis patients and healthy controls

Osteoarthritis (OA) is largely considered to be a non-inflammatory disease, although there is compelling evidence that subclinical inflammation is a common event, even in the absence of acute inflammatory flares. In this study we analyze, by means of CD5 and CD69 expression, the infiltration and early activation of CD5+cells, mostly lymphocytes, in both synovial membrane and synovial fluid from advanced OA patients and compare them with samples from patients with rheumatoid arthritis and healthy controls. The number of infiltrating CD5+ cells in both synovial membrane and synovial fluid from patients with advanced OA was significantly reduced as compared with rheumatoid arthritis patients. However, synovial membrane and synovial fluid CD5+ cells on OA exhibited a phenotype with evidence of recent activation comparable to that observed in RA.

Unreamed intramedullary locking nailing for open tibial fractures

Summary. We reviewed the results of the treatment of 24 cases of open tibial fractures using unreamed intramedullary locking nailing. The fractures were classified, following the Gustilo system as grade I-7, grade II-7 and grade III-10. The average time to achieve bony union was 22 weeks with a 26% incidence of pseudoarthrosis. There were no cases of deep infection. Five cases healed with shortening of over 1 cm, but we did not observe angular deformity in any of the patients. In 2 fractures with associated articular lesions, joint motion was limited at final follow up. The nail broke in 2 cases and the screws in 5. The surgical procedure is well tolerated by patients, allows good management of soft tissue lesions and rehabilitation with low rate of infection and malunion. The main disadvantages have been the relative high incidence of nonunion and breakage of metal.Résumé. Les auteurs rapportent les résultats du traitement de vingt-quatre fractures ouvertes de la jambe stabilisées avec un enclouage verrouillé sans alésage. On a classifié les fractures en suivant le systeme de Gustilo: 7 grade I, 7 grade II et 10 grade III. La moyenne de consolidation fut de 22 semaines avec un pourcentage de pseudarthroses de 26%. Il n’y a pas eu d’infection profonde. Cinq cas ont consolidé avec un raccourcissement de plus d’un cm mais on n’a pas observé d’angulation. On a noté une limitation de la mobilité articulaire chez deux patients qui avaient des lésions articulaires. On a eu deux ruptures du clou et cinq de vis. Nous concluons que cette technique chirurgicale est bien tolerée par la patient, elle permet un bon maniement des tissus nous, une réhabilitation précoce et elle a un pourcentage bas d’infection ou mauvaise consolidation. Le principal désavantage a été la relative incidence de pseudarthroses et de ruptures du matériel par stabilité insuffisante.

Midterm Results of Optetrak Posterior-Stabilized Total Knee System After 7 to 12 Years in a University Hospital

A clinical study has been carried out on 434 posterior-stabilized knee prostheses (Optetrak; Exactech, Gainesville, Fla) implanted between 1995 and 2000 in a university general hospital by 23 surgeons. At a mean follow-up of 8.8 years, 297 knees in 249 patients were available for review. Average patient age at surgery was 71.8 years. Average body mass index was 28.8 kg/m(2). Mean flexion range was 108° .The average knee score (Hospital for Special Surgery) increased from 48 points preoperatively to 86 points (60-97 points) at the final review. Of the patients, 81% had an excellent or good result, 14.9% had a fair result, and 4.1% had a poor result. Using the Kaplan-Meier method, we obtained a 91.3% predicted implant survival at 12 years including septic and aseptic revision in the best-case scenario.

The ubiquitin–proteasome pathway and viral infections in articular cartilage of patients with osteoarthritis

Many viruses can evolve different strategies to exploit the ubiquitin–proteasome pathway (UPP) for their own benefit. Some data have recently established connections between UPP and osteoarthritis (OA). The aim of this study was to determine the possible involvement of viral infections linked with the UPP in the physiopathology of OA. Samples of human cartilage were obtained from 12 patients with clinical and radiological features of OA and from 12 normal controls. DNA was extracted from cultured chondrocytes from these patients, and quantitative real-time PCR was performed to analyse the DNA/RNA prevalence and viral loads of HSV, EBV, HCMV, enterovirus, and HTLV-1. The prevalence of total viral DNA/RNA among patients with OA was 16.7% (mean viral load of 7.86 copies/μg DNA), EBV being responsible for the two positive samples, while the prevalence in controls was 0%. We did not detect any positive samples for HSV, CMV, enterovirus, and HTLV-1 among patients with OA and controls. This first approach to the study of the prevalence of viruses linked to the UPP in articular cartilage of end-stage OA patients provides evidences supporting the risk of EBV transmission or reactivation in a subset of patients with disorders requiring tissue regeneration.

Recurrent total knee arthroplasty dislocation after dorsal meningioma diagnosed.

We report on a 68-year-old woman with gonarthrosis who underwent total knee arthroplasty. Having initially achieved a satisfactory result, she developed at 5 months postoperation an irreducible flexion contracture necessitating revision surgery; but no pathological findings were discovered. In the immediate postoperative period, the patient developed a severe spasm of the hamstring muscles and a paralysis of the external popliteal sciatic nerve with a posterior dislocation of the knee. After reduction, an electromyography study showed an alteration in medullary sensitive conduction; and the magnetic resonance image showed a lesion compatible with meningioma. This complication has not been previously described as a consequence of spinal tumor. Technical considerations are described for this rare complication, which remains a serious challenge for the orthopedic surgeon.

Fat embolism syndrome after nailing an isolated open tibial fracture in a stable patient: a case report

BackgroundFat embolism syndrome is a potentially fatal complication of long bone fractures. It is usually seen in the context of polytrauma or a femoral fracture. There are few reports of fat embolism syndrome occurring after isolated long bone fractures other than those of the femur.Case presentationWe describe a case of fat embolism syndrome in a 33-year-old Caucasian man. He was being seen for an isolated Gustilo’s grade II open tibial fracture. He was deemed clinically stable, so we proceeded to treat the fracture with intramedullary reamed nailing. He developed fat embolism syndrome intraoperatively and was treated successfully.ConclusionThis case caused us to question the use of injury severity scoring for isolated long bone fractures. It suggests that parameters that have been described in the literature other than that the patient is apparently clinically stable should be used to establish the best time for nailing a long bone fracture, thereby improving patient safety.