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Biomechanical analysis of three different types of fixators for anterior cruciate ligament reconstruction via finite element method: a patient-specific study

Zainal Abidin NA, Abdul Wahab AH, Abdul Rahim RA, Abdul Kadir MR, Ramlee MH

Med Biol Eng Comput, 2021 Sep;59(9):1945-1960.
PMID: 34392448 DOI: 10.1007/s11517-021-02419-6

Complication rates of anterior cruciate ligament reconstruction (ACL-R) were reported to be around 15% although it is a common arthroscopic procedure with good outcomes. Breakage and migration of fixators are still possible even months after surgery. A fixator with optimum stability can minimise those two complications. Factors that affect the stability of a fixator are its configuration, material, and design. Thus, this paper aims to analyse the biomechanical effects of different types of fixators (cross-pin, interference screw, and cortical button) towards the stability of the knee joint after ACL-R. In this study, finite element modelling and analyses of a knee joint attached with double semitendinosus graft and fixators were carried out. Mimics and 3-Matic softwares were used in the development of the knee joint models. Meanwhile, the graft and fixators were designed by using SolidWorks software. Once the meshes of all models were finished in 3-Matic, simulation of the configurations was done using MSC Marc Mentat software. A 100-N anterior tibial load was applied onto the tibia to simulate the anterior drawer test. Based on the findings, cross-pin was found to have optimum stability in terms of stress and strain at the femoral fixation site for better treatment of ACL-R.

Matched MeSH terms: Femur/surgery
Filling of the resultant cavity after curettage of benign bone tumours is still controversial

Ismail TB, Mahmoud MM, Ahmed OE, Bola AH, Bahaa ZH

Med J Malaysia, 2023 Mar;78(2):163-170.
PMID: 36988525

INTRODUCTION: Benign bone tumours occur most commonly during the first through third decades of life and often weaken the bones, which may predispose them to pathological fractures. Great diversity and debate in the management of primary bone tumours are based on the tumour extent. There has been an increasing trend toward the intra-operative filling of these lesions. We hypothesised that in some benign bone tumours, filling the resulting cavity after curettage was unnecessary. This study was carried out to determine whether it is necessary to fill the resultant cavity after the curettage of benign bone tumours and to represent various fillers.
MATERIALS AND METHODS: A retrospective study of patients diagnosed as benign bone tumours according to the Enneking classification who underwent simple or extended curettage at Menoufia university-Orthopedic Oncology Division (with or without grafting or filling) during the surgical treatment (Jan 2015 to Feb 2020). A review of the medical records was done. Lesions' size (length, width and depth) was measured on plain radiographs using the image j program. When applicable, degrees of filling of the resultant cavity were classified into four categories, according to Modified Neer's classification. Functional evaluation using the musculoskeletal tumour society (MSTS) score was reviewed.
RESULTS: Overall, 88 patients diagnosed with a primary bone tumour and who received the surgical intervention were included in the study. The mean age of the patients was 22.61+13.497 (3-58) years. There were 48 males and 40 females (54 right and 34 left). The mean follow-up period was 28.09+16.13 months. The most common location was the distal femur in 15 patients, the proximal femur in 10 patients and the proximal tibia in 12 patients. The most common diagnosis was giant cell tumour in 20 patients, followed by UBC in 19 patients, ABC in 15 patients and enchondroma in 13 patients. Twenty-three patients had simple curettage, while 65 patients had extended curettage. Mean MSTS was 28.78±1.68. Fifty-five lesions were classified according to modified Neer's classification.Thirtty-two patients were classified as type 1 with complete healing,22 patient was classified as type 2 with partial healing, and only one was classified as a recurrent lesion. Seven patients (7.9%) developed local recurrences.
CONCLUSION: Filling the resulting cavity after the removal of the pathological tissues is usually necessary but not always required. This is determined by the type of lesion and the size of the resulting cavity following curettage. Individualised surgery is required; additional fixation should be considered.

Matched MeSH terms: Femur/surgery
Fulltext Specificity of estimating femoral anteversion using linea aspera version for total hip arthroplasty: A three-dimensional computed tomography study

Mohamed Thajudeen MZ, Mahmood Merican A, Hashim MS, Nordin A

Medicine (Baltimore), 2022 Nov 11;101(45):e31398.
PMID: 36397421 DOI: 10.1097/MD.0000000000031398

Femoral anteversion is an important parameter that can prevent complication following total hip arthroplasty (THA) caused by improper positioning of the implant. However, assessing femoral anteversion can be challenging in situation with significant defect of the femoral neck. In this study, linea aspera version was nominated as alternative parameter to femoral anteversion. So, the main objective of this study is to determine whether femoral anteversion correlates with linea aspera version. Cross-sectional study. Three-dimensional images of 100 femora were generated and their femoral anteversion and linea aspera version was measured. Correlation between the parameters was calculated. The mean linea aspera version was 7.27° ± 12.17° (mean ± standard deviation) while the mean femoral anteversion was 11.84° ± 10.06°. The linea aspera version was inversely correlated with the femoral anteversion with a correlation coefficient of -0.85. Linea aspera should be considered as an additional bony landmark to assess proper implant positioning in THA.

Matched MeSH terms: Femur/surgery
The Relationship of Transepicondylar Width with the Distal and Posterior Femoral Condyles and Its Clinical Implications: A Three-Dimensional Study

Lee M, Ho JPY, Chen JY, Ng CK, Yeo SJ, Merican AM

J Knee Surg, 2022 Feb;35(3):280-287.
PMID: 32629512 DOI: 10.1055/s-0040-1713733

BACKGROUND: Restoration of the anatomical joint line, while important for clinical outcomes, is difficult to achieve in revision total knee arthroplasty (rTKA) due to distal femoral bone loss. The objective of this study was to determine a reliable method of restoring the anatomical joint line and posterior condylar offset in the setting of rTKA based on three-dimensional (3D) reconstruction of computed tomography (CT) images of the distal femur.
METHODS: CT scans of 50 lower limbs were analyzed. Key anatomical landmarks such as the medial epicondyle (ME), lateral epicondyle, and transepicondylar width (TEW) were determined on 3D models constructed from the CT images. Best-fit planes placed on the most distal and posterior loci of points on the femoral condyles were used to define the distal and posterior joint lines, respectively. Statistical analysis was performed to determine the relationships between the anatomical landmarks and the distal and posterior joint lines.
RESULTS: There was a strong correlation between the distance from the ME to the distal joint line of the medial condyle (MEDC) and the distance from the ME to the posterior joint line of the medial condyle (MEPC) (p

Matched MeSH terms: Femur/surgery
Advancement in total hip implant: a comprehensive review of mechanics and performance parameters across diverse novelties

Soliman MM, Islam MT, Chowdhury MEH, Alqahtani A, Musharavati F, Alam T, et al.

J Mater Chem B, 2023 Nov 15;11(44):10507-10537.
PMID: 37873807 DOI: 10.1039/d3tb01469j

The UK's National Joint Registry (NJR) and the American Joint Replacement Registry (AJRR) of 2022 revealed that total hip replacement (THR) is the most common orthopaedic joint procedure. The NJR also noted that 10-20% of hip implants require revision within 1 to 10 years. Most of these revisions are a result of aseptic loosening, dislocation, implant wear, implant fracture, and joint incompatibility, which are all caused by implant geometry disparity. The primary purpose of this review article is to analyze and evaluate the mechanics and performance factors of advancement in hip implants with novel geometries. The existing hip implants can be categorized based on two parts: the hip stem and the joint of the implant. Insufficient stress distribution from implants to the femur can cause stress shielding, bone loss, excessive micromotion, and ultimately, implant aseptic loosening due to inflammation. Researchers are designing hip implants with a porous lattice and functionally graded material (FGM) stems, femur resurfacing, short-stem, and collared stems, all aimed at achieving uniform stress distribution and promoting adequate bone remodeling. Designing hip implants with a porous lattice FGM structure requires maintaining stiffness, strength, isotropy, and bone development potential. Mechanical stability is still an issue with hip implants, femur resurfacing, collared stems, and short stems. Hip implants are being developed with a variety of joint geometries to decrease wear, improve an angular range of motion, and strengthen mechanical stability at the joint interface. Dual mobility and reverse femoral head-liner hip implants reduce the hip joint's dislocation limits. In addition, researchers reveal that femoral headliner joints with unidirectional motion have a lower wear rate than traditional ball-and-socket joints. Based on research findings and gaps, a hypothesis is formulated by the authors proposing a hip implant with a collared stem and porous lattice FGM structure to address stress shielding and micromotion issues. A hypothesis is also formulated by the authors suggesting that the utilization of a spiral or gear-shaped thread with a matched contact point at the tapered joint of a hip implant could be a viable option for reducing wear and enhancing stability. The literature analysis underscores substantial research opportunities in developing a hip implant joint that addresses both dislocation and increased wear rates. Finally, this review explores potential solutions to existing obstacles in developing a better hip implant system.

Matched MeSH terms: Femur/surgery
Letter to the editor regarding "Important tips and numbers on using the cortical step and diameter difference sign in assessing femoral rotation - Should we abandon the technique?"

Hwang PX, Wang CK

Injury, 2023 Nov;54(11):111038.
PMID: 37741171 DOI: 10.1016/j.injury.2023.111038

We have read the paper "Important tips and numbers on using the cortical step and diameter difference sign in assessing femoral rotation - Should we abandon the technique?" [1] with great interest. Restoring femoral rotation during intramedullary nailing can pose challenges to many experienced surgeons. Femur rotational side-to-side asymmetry which is greater than 10 ° will cause functional deficit. We propose a surgical technique which allows surgeons to evaluate and reduce the malrotated femur intraoperatively. This technique also improves the ergonomics of the surgery and can be used simultaneously with other femoral rotation evaluation techniques. LEVEL OF EVIDENCE: V.

Matched MeSH terms: Femur/surgery