The Variability of Femoral Rotational Alignment in Total Knee Arthroplasty

Siston, Robert A.; Patel, Jay; Goodman, Stuart B.; Delp, Scott L.; Giori, Nicholas J.

doi:10.2106/jbjs.d.02945

Cited by 177 publications

(72 citation statements)

References 29 publications

(28 reference statements)

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“…Both systems attempt to use anatomic landmarks to define femoral component rotation, but intraoperative identification of landmarks such as the femoral epicondyles has been shown to have high interobserver variability. Siston et al compared the TEAs established by 11 orthopaedic surgeons to a reference axis established using a digitized model and found that fewer than 17% of the TEAs marked by the surgeons were rotated less than 5° from the reference axis [28]. Similarly, Yan reported interobserver variations of 4.2° for the TEA [29].…”

Section: Discussionmentioning

confidence: 99%

Inter-Observer Precision and Physiologic Variability of MRI Landmarks Used to Determine Rotational Alignment in Conventional and Patient-Specific TKA

Park

Nam

Friedman

et al. 2015

The Journal of Arthroplasty

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Preoperative planning for patient-specific guides (PSGs) in total knee arthroplasty (TKA) requires identification of anatomic landmarks on three-dimensional imaging studies. The aim of this study was to assess the accuracy and precision with which landmarks commonly used to determine rotational alignment in TKA can be identified on magnetic resonance imaging (MRI). Two orthopaedic surgeons and two musculoskeletal radiologists independently reviewed a sequential series of 114 MRIs of arthritic knees. The magnitude of interobserver variability was high, suggesting an inherent risk of inconsistency when these landmarks are used in PSG fabrication. Additionally, there was a high degree of physiologic variation among patients, indicating that assuming standard relationships among anatomic landmarks when placing TKA components may lead to rotational malalignment relative to each patient's native anatomy.

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Section: Discussionmentioning

confidence: 99%

Inter-Observer Precision and Physiologic Variability of MRI Landmarks Used to Determine Rotational Alignment in Conventional and Patient-Specific TKA

Park

Nam

Friedman

et al. 2015

The Journal of Arthroplasty

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“…Whilst many opinions have been expressed in the literature as to which axes are the most reliable and/or show the least intra-/inter-observer variability, none seems to be superior [9].…”

Section: Introductionmentioning

confidence: 99%

Transepicondylar axis accuracy in computer assisted knee surgery: A comparison of the CT-based measured axis versus the CAS-determined axis

Zwaag

Valstar

Molen

et al. 2008

Computer Aided Surgery

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Rotational malalignment is recognized as one of the major reasons for knee pain after total knee arthroplasty (TKA). Although Computer Assisted Orthopaedic Surgery (CAOS) systems have been developed to enable more accurate and consistent alignment of implants, it is still unknown whether they significantly improve the accuracy of femoral rotational alignment as compared to conventional techniques. We evaluated the accuracy of the intraoperatively determined transepicondylar axis (TEA) with that obtained from postoperative CT-based measurement in 20 navigated TKA procedures. The intraoperatively determined axis was marked with tantalum (RSA) markers. Two observers measured the posterior condylar angle (PCA) on postoperative CT scans. The PCA measured using the intraoperatively determined axis showed an inter-observer correlation of 0.93. The intra-observer correlation, 0.96, was slightly better than when using the CT-based angle. The PCA had a range of -6 degrees (internal rotation) to 8 degrees (external rotation) with a mean of 3.6 degrees for observer 1 (SD = 4.02 degrees ) and 2.8 degrees for observer 2 (SD = 3.42 degrees ). The maximum difference between the two observers was 4 degrees . All knees had a patellar component inserted with good patellar tracking and no anterior knee pain. The mean postoperative flexion was 113 degrees (SD = 12.9 degrees ). The mean difference between the two epicondylar line angles was 3.1 degrees (SD = 5.37 degrees ), with the CT-based PCA being larger. During CT-free navigation in TKA, a systematic error of 3 degrees arose when determining the TEA. It is emphasized that the intraoperative epicondylar axis is different from the actual CT-based epicondylar axis.

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“…A number of anatomical landmarks have been proposed to achieve correct rotational alignment, such as the posterior condylar axis (PCA), surgical transepicondylar axis, clinical transepicondylar axis (CEA), and anteroposterior trochlear axis (i.e., Whiteside's anteroposterior axis) (3,4). The transepicondylar axis has been demonstrated, in theory, to be a reliable rotational reference line for properly placing the femoral component (5-7), but identifying it intraoperatively is difficult in some cases because of the low-profile geometry of and/or soft tissues covering the epicondyles (8,9). Therefore, surgeons typically estimate the transepicondylar axis from the PCA by using the twist angle determined on preoperative X-rays or computed tomography (CT) scans and set the cutting guide based on these measurements.…”

Section: Introductionmentioning

confidence: 99%

The Posterior Condylar Cartilage Affects Rotational Alignment of the Femoral Component in Varus Knee Osteoarthritis

et al. 2017

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: Rotational alignment of the femoral component in total knee arthroplasty (TKA) is important for patellar tracking and ligament balance. Preoperative planning based on radiography might have a potential risk for over-rotation because these X-ray based measurements can not detect asymmetric cartilage wear on posterior condyle. The purpose of this study is to evaluate the effect of the posterior condylar cartilage of varus osteoarthritic knee on rotational alignment of the femoral component in TKA. We established two different condylar twist angles (CTA) from intraoperative multiplanar reconstruction (MPR) images and intraoperative information of navigation system. The CTA measured by a navigation system that includes the cartilage (4.8 2.0 ) was smaller than those measured by MPR images, which does not include the cartilage (6.6 2.1 ) (p 0.05). The difference between these two angles that corresponds to the remaining posterior condylar cartilage was 1.7 1.2 . This result demonstrated that the posterior condylar cartilage might lead to over-rotational of the femoral component in varus osteoarthritic knee. Therefore, when determining rotational alignment of the femoral component, surgeons should consider the effect of the remaining posterior condylar cartilage to avoid the over-rotation of the femoral component, especially in severe varus knees.

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The Variability of Femoral Rotational Alignment in Total Knee Arthroplasty

Cited by 177 publications

References 29 publications

Inter-Observer Precision and Physiologic Variability of MRI Landmarks Used to Determine Rotational Alignment in Conventional and Patient-Specific TKA

Inter-Observer Precision and Physiologic Variability of MRI Landmarks Used to Determine Rotational Alignment in Conventional and Patient-Specific TKA

Transepicondylar axis accuracy in computer assisted knee surgery: A comparison of the CT-based measured axis versus the CAS-determined axis

The Posterior Condylar Cartilage Affects Rotational Alignment of the Femoral Component in Varus Knee Osteoarthritis

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