Gellan-gum based bilayered scaffolds for application in osteochondral tissue engineering

Publicado em "Journal ofTissue Engineering and Regenerative Medicine", vol. 7, supp. 1 (2013)Bilayered scaffold and cellular strategies are currently applied to solve the challenging problem of osteochondral defects. In this study, several formulations of Gellan gum were developed to fabricate different scaf- folds possessing a cartilage-like layer and a bone-like layer. The bone- like layers were obtained by low acyl Gellan gum (LAGG) at 2 wt% and different amounts of hydroxyapatite powders (HAp) (5,10,15 and 20wt%). The cartilage-like layers were obtained by preparing LAGG formulation at 2wt% and formulations of LAGG at 2wt% and high acyl Gellan gum (HAGG) at 0.75wt% at a ratio of 75:25(v%). The visco- elastic measurements were performed using a TRITEC8000B DMA to characterize the mechanical behaviour of the bilayered scaffolds. The effect of the incorporation of different amount of HAp within the bone- like layer on the mechanical properties of the scaffolds was also investi- gated. Degradation and water uptake studies were performed by soak- ing the scaffolds in a phosphate buffered saline solution (pH 7.4) up to 30 days. The bilayered scaffolds were investigated by stereo microscope to evaluate the interface between both layers. The cytotoxicity of the bilayered scaffolds was investigated in vitro using a L929 cell line. In vi- tro studies regarding adhesion, encapsulation and viability of human chondrocytes (cartilage-like layer) and human osteoblasts (bone-like layer) cultured in the bilayered scaffolds were also carried by perform- ing SEM analysis and Live/Dead assays

Osteochondral transplantation using autografts from the upper tibio-fibular joint for the treatment of knee cartilage lesions

Purpose Treatment of large cartilage lesions of the knee in weight-bearing areas is still a controversy and challenging topic. Autologous osteochondral mosaicplasty has proven to be a valid option for treatment but donor site morbidity with most frequently used autografts remains a source of concern. This study aims to assess clinical results and safety profile of autologous osteochondral graft from the upper tibio-fibular joint applied to reconstruct symptomatic osteochondral lesions of the knee. Methods Thirty-one patients (22 men and 9 women) with grade 4 cartilage lesions in the knee were operated by mosaicplasty technique using autologous osteochondral graft from the upper tibio-fibular joint, between 1998 and 2006. Clinical assessment included visual analog scale (VAS) for pain and Lysholm score. All patients were evaluated by MRI pre- and post-operatively regarding joint congruency as good, fair (inferior to 1 mm incongruence), and poor (incongruence higher than 1 mm registered in any frame). Donor zone status was evaluated according to specific protocol considering upper tibio-fibular joint instability, pain, neurological complications, lateral collateral ligament insufficiency, or ankle complaints. Results Mean age at surgery was 30.1 years (SD 12.2). In respect to lesion sites, 22 were located in weight-bearing area of medial femoral condyle, 7 in lateral femoral condyle, 1 in trochlea, and 1 in patella. Mean follow-up was 110.1 months (SD 23.2). Mean area of lesion was 3.3 cm 2 (SD 1.7), and a variable number of cylinders were used, mean 2.5 (SD 1.3). Mean VAS score improved from 47.1 (SD 10.1) to 20.0 (SD 11.5); p = 0.00. Similarly, mean Lysholm score increased from 45.7 (SD 4.5) to 85.3 (SD 7.0); p = 0.00. The level of patient satisfaction was evaluated, and 28 patients declared to be satisfied/very satisfied and would do surgery again, while 3 declared as unsatisfied with the procedure and would not submit to surgery again. These three patients had lower clinical scores and kept complaints related to the original problem but unrelated to donor zone. MRI score significantly improved at 18–24 months comparing with pre-operative (p = 0.004). No radiographic or clinical complications related to donor zone with implication in activity were registered. Conclusions This work corroborates that mosaicplasty technique using autologous osteochondral graft from the upper tibio-fibular joint is effective to treat osteochondral defects in the knee joint. No relevant complications related to donor zone were registered

Restoring tibiofemoral alignment during ACL reconstruction results in better knee biomechanics

"Published online: 24 October 2017"PURPOSE: Anterior cruciate ligament (ACL) reconstruction (ACLR) aims to restore normal knee joint function, stability and biomechanics and in the long term avoid joint degeneration. The purpose of this study is to present the anatomic single bundle (SB) ACLR that emphasizes intraoperative correction of tibiofemoral subluxation that occurs after ACL injury. It was hypothesized that this technique leads to optimal outcomes and better restoration of pathological tibiofemoral joint movement that results from ACL deficiency (ACLD). METHODS: Thirteen men with unilateral ACLD were prospectively evaluated before and at a mean follow-up of 14.9 (SD = 1.8) months after anatomic SB ACLR with bone patellar tendon bone autograft. The anatomic ACLR replicated the native ACL attachment site anatomy and graft orientation. Emphasis was placed on intraoperative correction of tibiofemoral subluxation by reducing anterior tibial translation (ATT) and internal tibial rotation. Function was measured with IKDC, Lysholm and the Tegner activity scale, ATT was measured with the KT-1000 arthrometer and tibial rotation (TR) kinematics were measured with 3Dmotion analysis during a high-demand pivoting task. RESULTS: The results showed significantly higher TR of the ACL-deficient knee when compared to the intact knee prior to surgery (12.2° ± 3.7° and 10.7° ± 2.6° respectively, P = 0.014). Postoperatively, the ACLR knee showed significantly lower TR as compared to the ACL-deficient knee (9.6°±3.1°, P = 0.001) but no difference as compared to the control knee (n.s.). All functional scores were significantly improved and ATT was restored within normal values (P < 0.001). CONCLUSIONS: Intraoperative correction of tibiofemoral subluxation that results after ACL injury is an important step during anatomic SB ACLR. The intraoperative correction of tibiofemoral subluxation along with the replication of native ACL anatomy results in restoration of rotational kinematics of ACLD patients to normal levels that are comparable to the control knee. These results indicate that the reestablishment of tibiofemoral alignment during ACLR may be an important step that facilitates normal knee kinematics postoperatively. LEVEL OF EVIDENCE: Level II, prospective cohort study.The authors gratefully acknowledge the funding support from the Hellenic Association of Orthopaedic Surgery and Traumatology (HAOST-EEXOT)info:eu-repo/semantics/publishedVersio

Biomechanical considerations in the pathogenesis of osteoarthritis of the knee

Osteoarthritis is the most common joint disease and a major cause of disability. The knee is the large joint most affected. While chronological age is the single most important risk factor of osteoarthritis, the pathogenesis of knee osteoarthritis in the young patient is predominantly related to an unfavorable biomechanical environment at the joint. This results in mechanical demand that exceeds the ability of a joint to repair and maintain itself, predisposing the articular cartilage to premature degeneration. This review examines the available basic science, preclinical and clinical evidence regarding several such unfavorable biomechanical conditions about the knee: malalignment, loss of meniscal tissue, cartilage defects and joint instability or laxity

Medial Collateral Ligament Release During Knee Arthroscopy: Key Concepts

Complete access to the posterior medial compartment of the knee may represent a technical challenge during arthroscopy in patients with a tight tibiofemoral joint space.Medial collateral release reduces direct iatrogenic cartilage damage in the medial compartment of the knee through manipulation with instruments.We recommend performing medial collateral release in surgeries that access the posteromedial compartment (e.g. partial meniscectomy for ruptures of the posterior horn of medial meniscus or posterior root repairs) when the patient has a tight tibiofemoral joint space.There are two main techniques to perform medial collateral release: inside-out and outside-in. Regardless of the technique used, releasing medial ligament structures is a safe and effective method to be used in the diagnosis and treatment of injuries to the medial compartment.info:eu-repo/semantics/publishedVersio

Return to Play in Stress Fractures of the Hip, Thigh, Knee, and Leg

A stress fracture results from abnormal loading or inadequate recovery time following repeated loadings on bony structures. Stress fractures occur after an increase in frequency, duration, or intensity of exercise creating imbalance between bone resorption and formation, most frequently affecting athletes and young people. Both intrinsic and extrinsic risk factors have been established. An estimated 90% of stress fractures in athletes and footballers affect the lower limb, with the tibia being the second most frequent injury site followed by the pelvis. Clinical history and physical examination are critical for early diagnosis and optimal treatment. Plain radiographs have low sensitivity and are often inadequate to detect this condition. The most frequent imaging exam is currently MRI, which has good sensitivity and specificity. Conservative treatment is an appropriate and effective treatment in most cases. High-risk fractures (e.g., involving high tension sites or hypovascular zones) often require surgical treatment to facilitate healing and reduce risk of refracture. Location of the fracture, characteristics of the fracture and the athlete, and the level of competition must be taken into account during treatment decision-making. There are no perfect imaging techniques nor clear clinical evidence-based guidelines concerning return to play. However, as a â golden rule,â the athlete should be symptom-free for 2â 3 weeks before returning to the pitch. The fact that lower extremity stress fractures are relatively rare conditions creates increased difficulty in determining the effectiveness of treatments, particularly newer treatment options. This chapter provides a comprehensive management approach to stress fractures of the lower limb, with the exception of foot and ankle stress fractures, including the most updated information concerning optimal treatment and return to play.(undefined)info:eu-repo/semantics/publishedVersio

Using a cartographic model to assist medical diagnoses

Objective The main goal of the CHUB (cartographic human body) model is to introduce a cartographic approach that can assist the analysis, visualization and diagnosis of medical images and related data. Method Acartographic model is proposed as a reference framework for the development of computer systems and applications. This model accommodates subtle spatial features of these data that may facilitate diagnosis. Medical images and related data are structured into different “human-referenced” information layers. Algebraic map operations are used to combine these layers and achieve greater insights into the information content. Results Two case studies were considered to evaluate and validate the model: hydrokinetic therapy and the diagnosis of knee osteoarthritis. A prototype based on the CHUB model was implemented and two different approaches were performed to test and evaluate it. Full acceptance of the model was achieved by clinicians who used the CHUB system.Conclusion Acartographic model provides a feasible means for analyzing and visualizing medical image and related data. CHUB is a suitable model that may be used as a common framework for systems, applications and/or support tools that analyze and visualize medical images and related data (for example, in disease diagnosis)