Ana Leal

Asymmetric PDLLA membranes containing Bioglass ® for guided tissue regeneration: Characterization and in vitro biological behavior

OBJECTIVE In the treatment of periodontal defects, composite membranes might be applied to protect the injured area and simultaneously stimulate tissue regeneration. This work describes the development and characterization of poly(d,l-lactic acid)/Bioglass® (PDLLA/BG) composite membranes with asymmetric bioactivity. We hypothesized that the presence of BG microparticles could enhance structural and osteoconductivity performance of pure PDLLA membranes. METHODS The membranes were prepared by an adjusted solvent casting method that promoted a non-uniform distribution of the inorganic component along the membrane thickness. In vitro bioactive behavior (precipitation of an apatite layer upon immersion in simulated body fluid, SBF), SEM observation, FTIR, swelling, weight loss and mechanical properties of the developed biomaterials were evaluated. Cell behavior on the membranes was assessed using both human bone marrow stromal cells and human periodontal ligament cells. RESULTS Just the BG rich face of the composite membranes induced the precipitation of bone-like apatite in SBF, indicating that this biomaterial exhibit asymmetric osteoconductive properties. SEM images, DNA content and metabolic activity quantification revealed an improved cell adhesion and proliferation on the composite membranes. Composite membranes also stimulated cell differentiation, mineralization, and production of extracellular matrix and calcium nodules, suggesting the positive effect of adding the bioactive microparticles in the PDLLA matrix. SIGNIFICANCE The results indicate that the proposed asymmetric PDLLA/BG membranes could have potential to be used in guided tissue regeneration therapies or in orthopedic applications, with improved outcomes.

Patellofemoral Evaluation: Do We Need an Objective Kinematic Approach?

In the scope of patellofemoral research, there have been several efforts to understand the complexity of motion and forces involved. Nevertheless, several issues remain waiting for resolution. On the evaluation of symptomatic patellofemoral cases, one can realize that several limitations subside in the road from understanding etiology to clinical diagnosis. If in one hand it faces ambiguous and discrepant definitions due to its multifactorial origin, on the other hand, the assessment methods applied are inaccurate and nonobjective and present limited reliability and reproducibility. The present approach aims to contribute with an innovative solution, enabling objective anatomical and kinematic patellofemoral assessment.

Basics on Knee (dys)Function

The athlete’s body is in constant adaptation, i.e., the mechanotransduction phenomenon in stricto sensu and all the genotype-environment interactions in lato sensu occur in a continuum, delivering structural and functional effects which have their implications for recovering, maintenance, and development. Upon injuries and/or demanding for safe and greater performance, it is possible to set goals such as motor and physical improvements. This is possible through specific exercise aiming kinetics balance and motor learning. This has particular importance in the lower limb injuries since epidemiological studies clearly report the high incidence and severity in this body segment.

Patellofemoral Pain and Instability

Patellofemoral problems are well recognized as a critical puzzle. These are one of the most complex but neglected pathological conditions of the knee, so that has been leading to lack of both understanding and consensus on the entire analytical path, from diagnosis to treatment. In addition, patellofemoral disorders present a great incidence and strong negative long-term socioeconomic impact, especially considering its association with osteoarthritis. Higher incidence and severity of these pathologies are found in young women, as consequence of a combination of gender-specific sociological, anatomical, and physiological factors. Patellofemoral pain and instability frequently affect athletes, being common in all sports. This chapter will focus on the importance of this pathology in football.

TIBIOFEMORAL LATERAL COMPARTMENT'S MORPHOLOGY AS A RISK FACTOR: A RADIOGRAPHIC COMPARISON BETWEEN ACL-RUPTURED AND NON-INJURED SUBJECTS

Background Tibiofemoral bone morphology has been proposed as a potential risk factor for anterior cruciate ligament (ACL) rupture, with recent increasing interest in the lateral femoral condyle. Objective Investigate several tibiofemoral bone morphology measurements as risk factors for rupturing the ACL. Design Retrospective case–control study. Setting Clinical setting. Patients (or Participants) 200 ACL-ruptured patients and 200 normal subjects without history of previous knee injuries, with a mean age of 24 years old. Main Outcome Measurements Presence or not of ACL rupture. Assessment of Risk Factors Radiographic measurements of the distal epiphysis/diaphysis of the femur and proximal epiphysis of the tibia were performed, including: anteroposterior-flattened surface of the femurs lateral condyle; femurs diaphysis anteroposterior distance; anteroposterior distance of the femurs lateral condyle; height of the femurs lateral condyle; anteroposterior distance of the tibial plateaus; tibial slope. In addition, three morphological ratios were calculated. Results Most of the bone morphological parameters were different between genders (P<0.001). Similarly, there were significant differences between ACL-ruptured and control subjects (P<0.001), either for total sample or subgrouped by gender. Logistic regression model showed that 5 bone morphological parameters were significantly associated with ACL rupture (AUC=0.967, P<0.001). The calculated ratios showed significant accuracy in identifying individuals with higher risk of sustaining an ACL injury (P<0.001). Conclusions Several tibiofemoral bone morphology radiographic measurements are associated with an ACL rupture. Morphological ratios based on these measurements seem to identify individuals at higher risk of sustaining an ACL rupture. These findings might contribute to health counselling on level of sports participation. Moreover, it may help to identify individuals who may benefit the most from secondary prevention programs, where the risk of new injury is very high.

Pre-season isokinetic screening of neuromuscular risk factors in elite football

Background Neuromuscular isokinetic screening as a pre-season test may identify players at risk of injury or undertrained players. Objective Identify, assess and describe unilateral and bilateral knee muscular deficits in elite football players at pre-season screening. Design Retrospective cohort. Setting Elite football divisions. Patients (or Participants) Of 99 eligible male elite footballers, older than 17 years and without knee injury within the last 6 months, 3 were excluded, resulting in a final sample of 96 players (25 yrs old, BMI 23.7 kg·m−2). Assessment of Risk Factors Knee isokinetic assessment of both limbs was performed, starting with the non-dominant limb. The test range was set and gravity correction was performed. Before each isokinetic test, players were allowed 4 submaximal repetitions. The isokinetic test consisted of concentric sets of 6 and 8 repetitions, at 60˚/s and 180˚/s, respectively. Main Outcome Measurements Peak torque of knee extensors and flexors at 60˚/s and 180˚/s and conventional ratio at 60˚/s and 180˚/s. Individuals were also analysed for bilateral differences (>10%) and conventional ratio – Con/Con – (<0.47 and >0.80). Results Subgrouping by position, bilateral statistically significant differences were more frequent among defenders and goalkeepers, both for knee extensors and flexors (p<0.05). After individual analysis, 19% and 31% of players displayed significant bilateral asymmetries (>10%) for extensor peak torque at 60˚/s and 180˚/s, respectively; while 21% and 44% showed significant bilateral asymmetries for flexor peak torque at 60˚/s and 180˚/s, respectively. The conventional ratio was abnormal among 7% of players, for both dominant and non-dominant limbs at 60˚/s, and among 11% and 9% for dominant and non-dominant limbs, respectively, at 180˚/s. Conclusions Defenders and goalkeepers tended to present bilateral differences for isokinetic parameters more frequently than other player positions. There was a considerable proportion of players with clinically meaningful bilateral asymmetries, also impacting on unilateral balance. This screening is important to tailor neuromuscular programmes addressing deficits believed to be associated with injury risk, relevant in both primary and secondary injury prevention.

Design of a New Medical Device for Aiding Clinical Diagnosis of Patellofemoral Disorders

The purpose of this work is presenting the development of a medical device to assist on the diagnosis of patellofemoral disorders. Patellofemoral joint is one of the most complex articulations of the human body with high functional and biomechanical requirements. Anatomical and physiological abnormalities of this articulation result in knee problems with high social incidence. Their proper diagnosis and consequent correction might prevent or delay the development of diseases like arthritis, decreasing their long-term negative impact in life-quality and health economy. Clinical history, physical examination and imaging studies should be complementary procedures in the diagnosis of patellofemoral disorders, but until now they cannot be performed simultaneously. Furthermore, non-objectivity, inaccuracy and limited reliability and reproducibility are often found among assessment methods. Since the majority of the patellofemoral cases are recurrently misdiagnosed, there is in fact an urgent need for standardizing the whole methodology. From concept to design development, with strong clinical meaningful sustainability, we believe this work may give great contributions on these issues.

Treatment of Acute Patellar Dislocation: Current Concepts

Treatment of acute patellar dislocation has been surrounded by some controversy through the years. New options for diagnosis and treatment recently aroused thus stating the need for an updated approach to this topic. This chapter tries to address the following questions: (1) How should a first-time acute patellar dislocation be evaluated? (2) Which is the relevance of combined osteochondral fractures? (3) When should the initial management be surgical versus nonoperative treatment? A systematic review on the topic is provided.

Clinical diagnosis of patellofemoral disorders

The concept of bioengineering perfectly meets the purpose of building a bridge across two distinct but complementary areas: engineering and health sciences. The active cooperation of these scientific domains is the key solution to solve daily clinical problems. In fact, most of the medical devices currently available derive from last century engineering scientific discoveries. Thus, the biomedical engineer intervention plays an important and crucial role on the medical field evolution. In this work special emphasis is given to the patellofemoral (PF) joint due to the high complexity of this articulation and its pathological cases. There is an ambiguous definition of PF disorders, as long as they share a common thread with and have impact on nearly all knee conditions. Additionally, its multifactorial etiology intensifies the misunderstanding of its physiopathology, compromising its diagnosis, which de per se is actually performed in a non-rigorous, accurate nor reliable way. This research aims at analyzing the first steps of a main goal: develop a standard precise methodology to aid on the diagnosis of PF articulation. Starting by the description of the state of the art, this paper discusses the project methodology initially applied and highlights the future prospects for this work.