Mina Iravani, MSc; Farzam Farahmand, PhD; Soheil Mehdipour, MD
Abstract
Background: High tibial osteotomy (HTO) is a common surgical procedure for treatment of patients with varus malalignment. The success rate of the procedure is strongly dependent on the quality of correction. The purpose of this study was to simulate the HTO in a patient with varus deformity in order ...
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Background: High tibial osteotomy (HTO) is a common surgical procedure for treatment of patients with varus malalignment. The success rate of the procedure is strongly dependent on the quality of correction. The purpose of this study was to simulate the HTO in a patient with varus deformity in order to explore the interactions between the wedge angle, the mechanical axis, and the knee joint configuration.
Methods: A finite-element model of the knee joint of a patient with varus deformity was developed. The geometry was obtained using the whole limb CT scans and the knee MR images. The bones were assumed as rigid bodies, the articular cartilage and the meniscus as elastic solids, and the ligaments as nonlinear springs. A 600N force was applied at the femoral head in the line of the mechanical axis and the resulting knee configuration was investigated. The HTO was simulated by insertion of wedges with different angles beneath the tibial plateau and application of the resulting alteration of the loading axis in the model.
Results: The results indicated that the actual change of the mechanical axes was always smaller than was predicted by a geometric pre-planning approach that does not consider the effect of soft tissue on the post-operative configuration of the knee joint.
Conclusions: It was suggested that subject-specific models can improve the results of the HTO by simulating the operation before surgery and determining the optimal wedge angle that locates the mechanical axis in the middle of the knee.
Soheil Mehdipour, MD; Farid Abbaszadeh, MSc; Morad Karimpour, PhD; Farzam Farahmand, PhD; Zahra Saghaie, MSc
Abstract
Background: Conventional X-rays, due to 2D viewing, may not have accuracy in assessing lower limb deformities. The aim of this study was to analyze the deformities in 3D and simulated the corrective surgery in virtual space and to built patient-specific guide to achieve the precise correction.Methods: ...
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Background: Conventional X-rays, due to 2D viewing, may not have accuracy in assessing lower limb deformities. The aim of this study was to analyze the deformities in 3D and simulated the corrective surgery in virtual space and to built patient-specific guide to achieve the precise correction.Methods: In this descriptive study, 10 lower limbs with various deformities around the knee were studied. Weight bearing alignment x-rays and CT scans were processed digitally to produce 3D weight bearing models.The landmarks were determined and lower limb indices were calculated to determine the deformities in 3 dimensions Under surgeon's supervision, virtual correction of the deformity was performed, based on which, a patient-specific guide was designed and printed in 3D. The guide was then used in the surgery.Results: The deformity and deviation from standard angles was obsereved in frontal plane in 6 cases, frontal and sagittal planes in one, frontal and axial planes in two, and a three planar deformity in one cases. The results showed that this method is effective in achieving the precise correction of the deformity. In all the patients who underwent surgery, the correction was the same or very close to what had been planned in frontal and sagittal planes (±1). Clinical assessment was used for rotational correction in the absence of postoperative CT-scan.Conclusions: The computer-assisted pre-op planning and patient-specific guide usage can highly optimize the results of corrective osteotomies, especially in difficult deformities around the knee.
Firooz Madadi, MD; Mohammad Reza Abbassian, MD; Fooad Rahimi, MD; Farivar Abdollahzadeh Lahiji, MD; Armin Aalami Harandi, MD; Farzam Farahmand; Tahereh Yazdanyar; Firozeh Madadi; Reza Sadeghian
Abstract
Background: Several different methods for fixation of grafts in anterior cruciate ligament (ACL) reconstruction have been used. The purpose of present study is to compare two techniques of tibial fixation in hamstring quadruple graft reconstruction. Methods: In a randomized clinical trial study, 46 ...
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Background: Several different methods for fixation of grafts in anterior cruciate ligament (ACL) reconstruction have been used. The purpose of present study is to compare two techniques of tibial fixation in hamstring quadruple graft reconstruction. Methods: In a randomized clinical trial study, 46 cases of isolated tears were reconstructed using hamstring grafts. In 24 cases the tibial fixation sites were fixed with interference screw, and in 22 patients the remnant end of graft at tibia was passed through a bony tunnel and fixed with suture to the bone. The cases were all assessed with a mean follow-up of one year with “Cincinnati knee ligament rating scale” and “KT-2000” examination.Results: The score in 22 “target group” cases was 8, and in 24 “control group” was 9. In “KT-2000” examination, 11 patients of double fixation were excellent and 11 good. In control group 4 cases had excellent and 20 good results (p < /em>=0.01).Conclusions: Double tibial fixation for ACL reconstruction with Hamstring tendon graft has a better outcome on “Symptom” evaluation and “KT-2000” instrument compared to single tibial-site fixation.
