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Prediction of Surgical Procedures Effect on Mal-tracking Correction of Patello-femoral Joint Using Patient-specific Musculo-skeletal Modeling

Abedi, Rasoul | 2014

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  1. Type of Document: M.Sc. Thesis
  2. Language: Farsi
  3. Document No: 46765 (08)
  4. University: Sharif University of Technology
  5. Department: Mechanical Engineering
  6. Advisor(s): Farahmand, Farzam; Zohoor, Hassan
  7. Abstract:
  8. According to the statistical studies, knee pain is the most common and costliest disorder after low back pain. One of its types is the patello-femoral disorder and instability. Patellar instability can be affected by different factors, such as: low depth of the trochlear groove, low height of the lateral femoral condyle, high length of the patellar tendon, abnormal lateral rotation of the tibia, unusual tibial attachment of the patellar tendon, small patellar size, general loosening of ligaments, etc. So, the mechanical properties of knee joint including patello-femoral joint, surrounding soft tissues, and incoming forces must be examined carefully, in order to find out suitable and effective solutions for treatment of these kinds of disorders. Several 2D and 3D anatomical models have been developed since recent years. In 2D models, the knee is joint often simulated in sagittal plane and the real joint geometry is not considered completely. In other words, the sagittal projection of the joint surface and attachment points of muscle, tendon and ligament, is often used in these models. Subsequently, 3D models became more complete. It can be possible to simulate the accurate geometry of joint and cartilage, using developed numerical solutions and finite element methods. But, some difficulties like: long time solving and diverging in some conditions, have caused problems in dynamic analyzing of the most models. A number of subject-specific models which were more developed, have studied the influence of some disorders and surgical methods simply in a limited way at patellar tracking and joint contact.It is essential to develop a more detailed patello-femoral model according to the recent studies, in order to simulate patellar disorders and surgery. The purpose of this study is to develop a patient-specific musculo-skeletal model of the patello-femoral joint, so that the joint behavior can be simulated before and after patellar surgery by using this model. By continuing this method in the future, it will be possible to predict the quality of surgical procedures for patients who haven’t been operated yet. Therefore, modeling process habe been performed in two scales. In larger scale, a musculo-skeletal model of lower extremity which has got corrected Hill-modeled muscles and optimization methods, have been used. In smaller scale, a developed patella-femoral patient-specific model (with patellar instability) have been used by means of detailed bones, joint cartilage, ligaments and patellar tendon, which the muscle fibers are its inputs as force lines and are resulted from larger scale. Patient patellar tracking was measured and validated by means of 1.5 Tesla MRI images in knee free flexion from 0 to 40 degrees at sleeping mode. The model have predicted the general process of translations and rotations suitably. At last, the surgical procedures of MPFL reconstruction , lateral release, and tibial tubercle medial-translation, were applied to the model independently and together. The most effective surgical method was the third one and the best method was the combination of three surgeries, which corrects the patellar mal-tracking of the patient to its normal range more than other methods
  9. Keywords:
  10. Quadriceps Muscles ; Patellofemoral Joint ; Anybody Software ; Tibial Tubercle ; Subject-Specific Model

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