The Rotational alignment is an important factor for survival total knee Arthroplasty. Rotational malalignment causes knee pain, global instability, and wear of the polyethylene inlay. Also, the anterior cortex line was reported that more reliable and more easily identifiable landmark for correct tibial component alignment. The aims of the current study is to identify effect of inserting the tibial baseplate of using anterior cortex line landmark of TKA on stress/strain distributions within cortical bone and bone cement. Through the current study, final aim is to suggest an alternative position of tibia baseplate for reduction of TKA failures with surgical convenience. A three-dimensional tibia FE model with TKA was generated based on a traditional TKA surgical guideline. Here, a commercialized TKA (LOSPA, Corentc, Korea) was considered corresponded to a patient specific tibia morphology. Tibia baseplate was positioned at anterior cortex line. Alternative two positions were also considered based on tibia tuberosity 1/3 line and tibia tuberosity end line known as a gold standard Introduction
Materials and Method
Revision total knee arthroplasy (TKA) has been often used with a metal block augmentation for patients with poor bone quality. However, bone resorption beneath metal block augmentation has been still reported and little information about the reasons of the occurrence of bone resorption is available. The aim of the current study is to identify a possibility of the potential occurrence of bone resorption beneath metal block augmentation, through evaluation of strain distribution beneath metal block augmentation in revision TKA with metal block augmentation, during high deep flexion. LOSPA, revision TKA with a metal block augmentation (Baseplate size #5, Spacer size #5, Stem size Φ9, L30, Augment #5 T5) was considered in this study. For the test, the tibia component of LOSPA was implanted to the tibia sawbone (left, #3401, Sawbones EuropeAB, Malmö, Sweden), which was corresponded to a traditional TKR surgical guideline. The femoral component of LOSPA was mounted to a customized jig attached to the Instron 8872 (Instron, Norwood, MA, USA), which was designed specially to represent the angles ranged from 0° to 140° with consideration of a rollback of knee joint (Figure. 1). Here, a compressive load of 1,600N (10N/s) was applied for each angle. Strain distribution was then measured from rossete strain gauge (Half Bridge type, CAS, Seoul, Korea) together (Figure 1).Introduction
Materials and Method
Revision total knee arthroplasty (TKA) has been often used with a metal block augmentation for patients with poor bone quality. However, bone defects are frequently detected in revision TKA used with metal block augmentation. This study focused on identification of a potential possibility of the bone defect occurrence through the evaluation of the strain distribution on the cortical bone of the tibia implanted revision TKA with metal block augmentation, during high deep flexion. Composite tibia finite element (FE) model was developed and revision TKA FE model with a metal block augmentation (Baseplate size #5 44AP/67ML, Spacer size #5 44AP/67ML, Stem size Φ9, L30, Augment #5 44AP/67ML thickness 5mm) was integrated with the composite tibia FE model. 0°, 30° 60°, 90°, 120° and 140° flexion positions were then considered with femoral rollback phenomenon [Introduction
Materials and Methods
Altered joint mechanics produced by periarticular bone remodelling may precede the cartilage changes of osteoarthritis (OA). Recently, receptor activator of nuclear factor kappa beta (RANK), along with its soluble ligand (RANK-L), have been shown to induce both maturation and activation of bone-degrading osteoclasts. Activation of RANK on osteoclast cells by RANK-L is opposed by another soluble factor, osteoprotegerin (OPG). Thus RANK/OPG balance is important in regulating bone turnover. Here, we compared periarticular bone from patients with end-stage OA undergoing total knee arthroplasty (TKA) with those of cadaveric controls. We assessed bony, histological and molecular changes that are important in the pathogenesis of OA. Using in-situ hybridization, we found increased staining of digoxygenase (DIG)-labelled OPG in osteoblasts of TKA bone. A corresponding increase in subchondral and insertional bone was seen on micro-CT (μCT) sections from TKA bone in comparison with cadaveric controls. Those changes were accompanied by marked articular cartilage degeneration on histology. This study is the first of which we are aware that directly assessed the role of OPG in inducing the bony changes seen in human end-stage OA. We used μCT to compare corresponding samples qualitatively from TKA and cadaveric bone. Adjacent sections underwent hybridization of digoxygenase (DIG)-labelled OPG riboprobes to assess gene expression in situ. Finally, samples were stained and analysed for histology. Bony hypertrophy may be a result of overexpression of OPG that occurs as an important feature of OA pathophysiology. Funding: This work was supported by a grant from the Hip Hip Hooray Fund of the Canadian Orthopaedic Research Foundation (CORF) and the Wood Professorship in Joint Injury Research. There was no commercial funding for this research project.
