Influence of Sex and Knee Joint Rotation on Patellofemoral Joint Stress through a Mathematical Modelling Study

Background: Females are two times as likely to experience patellofemoral pain syndrome (PFPS) than males; however, the reason for this sex difference remains unclear. Patellofemoral joint (PFJ) stress is believed to contribute to PFPS alterations through knee joint rotation alignment, but the influence of knee joint rotation conditions on PFJ stress is unclear. We aimed to investigate the influence of sex and knee joint rotation alignment on PFJ stress. Methods: Simulation ranges were set to knee joint flexion angles of 10°-45° (common to both sexes) and extension moments of 0-240 Nm (males) and 0-220 Nm (females). The quadriceps force and effective lever arm length at the quadriceps muscle were determined as a function of the knee joint flexion angle and extension moment. The PFJ contact area, which is specific to sex, and knee joint rotation was calculated from cadaver data, and PFJ stress was estimated. Results: In all knee joint rotation conditions, PFJ stress was higher in females than in males. Additionally, PFJ stress in males and females was the largest under neutral conditions compared with other rotation conditions. Conclusion: The results may be useful for understanding the underlying mechanisms contributing to the differences in PFPS in males and females.

A Basketball Technique Balance Control Technology Based on Ant Colony Algorithm

Aiming at the problems of low accuracy, poor stability, and effect of balance control in the current basketball skill balance control process, a basketball skill balance control method based on ant colony algorithm is proposed. The principle and characteristics of ant colony algorithm are analyzed, the mathematical model of ant colony algorithm is established, and the implementation steps of ant colony algorithm are given. According to the balance and stability control principle of basketball skills, this paper constructs the balance and stability control model of basketball skills. By establishing the knee-ankle-foot joint analysis model and using the ant colony algorithm, the basketball movement path is constructed. Through the fitness function, select the basketball motion path nodes and update the pheromone, obtain the relationship between the internal stress and displacement of the body under different force directions, and obtain the influence law of the effective knee joint stress with the varus and internal rotation, so as to achieve the balance and stability of the basketball skills sexual control analysis. The experimental results show that the proposed method has better stability and effect of basketball technique balance control and can effectively improve the accuracy of basketball technique balance control.

KNEE INJURIES PREVALENCE IN BRAZILIAN JIU-JITSU: EPIDEMIOLOGICAL STUDY

ABSTRACT Objective: To evaluate the epidemiological and clinical characteristics of knee injuries in Brazilian Jiu-Jitsu (BJJ) practitioners. Methods: Cross-sectional study, using a mixed questionnaire, based on the Referred Morbidity Index. Results: 198 amateur and professional BJJ fighters, of both sexes, aged between 18 and 60 years, participated in the study. The majority (88%) of the fighters had only one knee injury (p < 0.001). In total, 29.8% proportion of knee injuries (p < 0.001) was identified, which were mainly from the medial collateral ligament (38%), caused by a sprain mechanism (86%) and conservative treatment (65%). Conclusion: A high prevalence of knee injuries in JJB fighters was found, compared to other sports that also perform rotational movements and have great body contact, such as mixed martial arts (MMA), judo, soccer, basketball and handball. Some JJB strikes, such as the key and the projection, can cause greater knee joint stress, both in the attacking fighter and in the opponent. The knowledge of the epidemiological characteristics of sports injuries is important in the elaboration of prevention and training protocols more specific to the sport and for the understanding of the complex mechanisms involved with this outcome in sport. Level of Evidence IV, Case Series.

Influence of Sex And Knee Joint Rotation On Patellofemoral Joint Stress Through A Mathematical Modelling Study

Background: Females are two times as likely to experience patellofemoral pain syndrome (PFPS) than males; however, the reason for this sex difference remains unclear. Patellofemoral joint (PFJ) stress is believed to contribute to PFPS alterations through knee joint rotation alignment, but the influence of knee joint rotation conditions on PFJ stress is unclear. We aimed to investigate the influence of sex and knee joint rotation alignment on PFJ stress. Methods: Simulation ranges were set to knee joint flexion angles of 10°-45° (common to both sexes) and extension moments of 0-240 Nm (males) and 0-220 Nm (females). The quadriceps force and effective lever arm length at the quadriceps muscle were determined as a function of the knee joint flexion angle and extension moment. The PFJ contact area, which is specific to sex, and knee joint rotation was calculated from cadaver data, and PFJ stress was estimated. Results: In all knee joint rotation conditions, PFJ stress was higher in females than in males. Additionally, PFJ stress in males and females was the largest under neutral conditions compared with other rotation conditions. Conclusion: The results may be useful for understanding the underlying mechanisms contributing to the differences in PFPS in males and females.

BIOMECHANICAL ENERGY METABOLISM MODEL OF SPORTS MEDICINE

ABSTRACT Introduction: This is a study on the reasonable organization and collocation of sports health elements in different sports forms, and how this is reflected through scientific exercise instructors. Objective: To improve the effect of sports medicine on the biomechanical energy metabolism of human health. Methods: The biomechanical model of knee joint stress was used to analyze the mechanical behavior of knee joint flexion, such as movement and contact; the variation law and peak value of stress on the contact surface of the tibiofemoral joint were obtained. Results: Based on the changes of stress on tibiofemoral joint contact surface and the peak value of the data obtained in this paper, the model and data basis were provided for guiding scientific sports training and sports medicine treatment, preventing knee joint sports injury, knee joint inflammation, and reasonably improving sports performance. Conclusions: Sports medicine is effective in improving human health. The objects of clinical exercise guidance include all people, from infancy to the old age. The function of exercise is recognized in the effect of the whole process of prevention, treatment and rehabilitation of a variety of clinical diseases. The effectiveness of exercise in the whole process of disease is also recognized. Level of evidence II; Therapeutic studies - investigation of treatment results.

The importance of Böhler’s angle in calcaneus geometry: A finite element model study

Objectives: Calcaneal fractures are the most common tarsal fractures following a foot-ankle trauma. The Böhler’s angle is an important measurable angle before, during, and after surgery. In this study, we aimed to investigate correlation between Böhler’s angle, calcaneal strength, and subtalar joint stress using a finite element analysis (FEA). Patients and methods: Between January 2016 and December 2016, computed tomography (CT) scans were used with MIMICS® software for FEA. The ankle and foot of a 23-year-old male person with a height of 180 cm and weighing 80 kg was modeled as reference. Raw coronal CT images were obtained in Digital Imaging and Communications in Medicine format with the resolution of 512X512 pixels and 0.3-mm slice intervals in 135 kV. The structures including tibia, fibula and 26 other bones (talus, calcaneus, cuboid, navicular, three cuneiforms, five metatarsals, and 14 components of phalanges), cartilage and ligamentous tissues were modeled to form ankle joint. After determining Böhler’s angle as 35 degrees for the reference model, a fracture line was created on calcaneus. Calcaneus was remodeled with the Böhler’s angle of 45, 40, 30, 25, 20, 10, and 0 degrees respectively. All models were transferred to ANSYS software for FEA and the loads on the lower extremities with normal posture were applied on models. Results: Analysis of all models based in the reference model revealed that maximum tension values on calcaneus increased, while the Böhler’s angle decreased, indicating a statistically significant difference. The decreased Böhler’s angle indicated statistically significantly higher maximum tension values (p=0.04). Action force in subtalar joint was evaluated by comparing with the forces in reference model. The increased Böhler’s angle was found to be associated with statistically significantly decreased amount of load on subtalar joint. The decreased Böhler’s angle was related to the statistically significantly increased amount of load on subtalar joint. Conclusion: Our study results suggest that decreased Böhler’s angle increases the possibility of subtalar arthrosis, although overcorrection of the Böhler’s angle seems not to increase the risk of subtalar arthrosis.

Outcomes After Deepening Trochleoplasty and Concomitant Realignment in Patients With Severe Trochlear Dysplasia With Chronic Patellofemoral Pain: Results at 2-Year Follow-up

Background: Abnormal patellofemoral joint stress appears to have major relevance in a subgroup of patients with patellofemoral pain (PFP). Purpose: To evaluate whether patients with chronic PFP and trochlear dysplasia–induced patellofemoral joint malalignment benefit from a deepening trochleoplasty procedure with the aim of improving patellotrochlear congruence. Study Design: Case series; Level of evidence, 4. Methods: Included were 15 patients (male/female, 1/14; mean age, 30.3 years [range, 19-51 years]) with 8.8 years (range, 1-20 years) of chronic PFP and severe trochlear dysplasia. All patients underwent correction of patellotrochlear malalignment with deepening trochleoplasty and concomitant realignment procedures. The Kujala score and a numerical analog scale (0-10) for intensity of pain were used to assess symptoms preoperatively and at 12 and 24 months postoperatively. Pre- and postoperative magnetic resonance imaging (MRI) scans from the patients were compared with the MRI scans of age- and sex-matched controls regarding the patellotrochlear contact area and contact ratio, patellar tilt, patellotrochlear index, and lateral trochlear inclination (LTI) angle. Results: The Kujala score increased from a mean of 55 (range, 15-81) preoperatively to 82.5 (range, 53-98) after 12 months (95% CI, –42.56 to –12.37; P < .001) and to 84.2 (range, 59-99) after 24 months (95% CI, –44.29 to –14.11; P < .001). The intensity of PFP decreased from 5.7 (range, 3-10) preoperatively to 1.4 (range, 0-4) after 12 months (95% CI, 2.57 to 5.96; P < .001) and had a mean of 1.6 (range, 0-6) after 24 months (95% CI, 2.44 to 5.75; P < .001). Preoperatively, parameters in the study group indicated significant patellotrochlear malalignment, which improved and normalized (except for the LTI angle) postoperatively compared with the values of the control group ( P > .05). Conclusion: In a subgroup of patients with chronic PFP due to severe trochlear dysplasia, deepening trochleoplasty and concomitant realignment procedures significantly reduced pain and improved knee joint function while normalizing patellotrochlear congruence.