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

Zwaag, Henrica M. J. van der Linden–van der; Valstar, Edward R.; Molen, Aart J. van der; Nelissen, Rob G H H

doi:10.3109/10929080802240134

Cited by 37 publications

(31 citation statements)

References 32 publications

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“…With navigation, femoral and tibial rotation was optimal more frequently, but the number of outliers could not be reduced. This is in accordance with a recent publication that showed that the virtual individual rotational position of the femoral component using a CAOS system is significantly different from its position on a postoperative CT scan [6]. In CT-less navigation the accuracy of the implantation depends on the exact identification of anatomic landmarks, which can be difficult [5].…”

Section: Discussionsupporting

confidence: 86%

“…The digitalization of the bony landmarks is one of the crucial steps in navigation. Problems of reproducibility with intraoperative termination of these landmarks have been described to especially appear with the femoral epicondyles [5,6]. The debate on how reliably these landmarks can be localized within surgery and assessed by computed tomography persists.…”

Section: Discussionmentioning

confidence: 99%

“…Especially malrotation of components is reported to be a common source for postoperative pain and revisions. Diagnosis of malrotation is challenging since it usually requires computed tomography (CT) [3,4] and bony landmarks (usually the femoral epicondyles) can provoke imprecision with and without navigation [5,6]. …”

Section: Introductionmentioning

confidence: 99%

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Navigation of total knee arthroplasty: rotation of components and clinical results in a prospectively randomized study

Schmitt

Hauk

Kienapfel

et al. 2011

BMC Musculoskelet Disord

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BackgroundNavigation was introduced into total knee arthroplasty (TKA) to improve accuracy of component position, function and survival of implants. This study was designed to assess the outcome of navigated TKA in comparison with conventional implantation with the focus on rotational component position and clinical mid-term results.MethodsIn a prospectively randomized single-blinded approach, 90 patients with primary gonarthrosis were assigned to three different groups. Thirty patients each were assigned to NexGen LPS without and with navigation (groups 1 and 2), and 30 patients to navigation with the Stryker Scorpio PS (group 3). The navigation system used was the imageless Stryker KneeTrac, version 1.0. Clinical outcome was assessed by a blinded observer applying the Knee Society Score (KSS) and a visual analogue scale (VAS) for pain. CT scans and radiographs were conducted prior to and 12 weeks after index surgery.ResultsSeventy-nine patients were available for clinical evaluation at 3 ± 0.4 years follow-up. Four implants had to be revised for early loosening or infection (4.4%). Four patients had died and three patients were not able to follow the invitation for clinical assessment. Functional results in the KSS were significantly lower after navigated TKA. Operation time and incisions with navigation were significantly longer. Significantly less radiological outliers with navigation were found for coronal alignment of the femur, only.ConclusionIn this series, no beneficial effect for navigation in TKA could be shown assessing clinical data, as functional results in the presented series seemed to be lower after first generation navigated TKA. The clinical mid- to long-term value of navigation remains to be evaluated in larger patient series or meta-analyses at longer follow-up.Trial registration numberDRKS 00000430

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Section: Discussionsupporting

confidence: 86%

Section: Discussionmentioning

confidence: 99%

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Navigation of total knee arthroplasty: rotation of components and clinical results in a prospectively randomized study

Schmitt

Hauk

Kienapfel

et al. 2011

BMC Musculoskelet Disord

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“…This variation is, for example, described for the epicondylar axis. A systematic error of 3° was found using the same navigation module by Van der Linden et al [30]. Several authors [13, 20] concluded that, because of this problem, preoperative CT scanning is a more appropriate method because of the fact that using computer navigation, rotation is still based on a controversial intraoperative identification of the axes.…”

Section: Discussionmentioning

confidence: 99%

A computed tomography based study on rotational alignment accuracy of the femoral component in total knee arthroplasty using computer-assisted orthopaedic surgery

Zwaag

Bos

Heide

et al. 2010

International Orthopaedics (SICOT)

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Rotation of the femoral component in total knee arthroplasty (TKA) is of high importance in respect of the balancing of the knee and the patellofemoral joint. Though it is shown that computer assisted surgery (CAOS) improves the anteroposterior (AP) alignment in TKA, it is still unknown whether navigation helps in finding the accurate rotation or even improving rotation. Therefore the aim of our study was to evaluate the postoperative femoral component rotation on computed tomography (CT) with the intraoperative data of the navigation system. In 20 navigated TKAs the difference between the intraoperative stored rotation data of the femoral component and the postoperative rotation on CT was measured using the condylar twist angle (CTA). This is the angle between the epicondylar axis and the posterior condylar axis. Statistical analysis consisted of the intraclass correlation coefficient (ICC) and Bland-Altman plot. The mean intraoperative rotation CTA based on CAOS was 3.5° (range 2.4–8.6°). The postoperative CT scan showed a mean CTA of 4.0° (1.7–7.2). The ICC between the two observers was 0.81, and within observers this was 0.84 and 0.82, respectively. However, the ICC of the CAOS CTA versus the postoperative CT CTA was only 0.38. Though CAOS is being used for optimising the position of a TKA, this study shows that the (virtual) individual rotational position of the femoral component using a CAOS system is significantly different from the position on a postoperative CT scan.

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“…The WL, defined as the line connecting the deepest part of the anterior patellar groove (APG) to the center of the posterior intercondylar notch (PIN), is traditionally used in TKR as a reference for assessment of the femoral component rotation [23][24][25] as an alternative to the transepicondiylar axis (TEA). While the TEA has been largely used to approximate the optimal flexion-extension axis of the knee [26][27][28][29][30][31], the WL has been shown to be a valuable alternative to the TEA in severely valgus knees [32].…”

Section: Introductionmentioning

confidence: 99%

Determination of the Whiteside line on femur surface models by fitting high-order polynomial functions to cross-section profiles of the intercondylar fossa

Cerveri¹,

Marchente²,

Manzotti³

et al. 2011

Computer Aided Surgery

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Innovative methods for morphological and functional analysis of bones have become a primary objective in the development of planning systems for total knee replacement (TKR). These methods involve the interactive identification of clinical landmarks (reference points, distances, angles, and functional axes of movement) and the determination of the optimal implant size and positioning. Among the functional axes used to estimate the correct alignment of the femoral component, the Whiteside line, namely, the anterior-posterior (AP) direction, is one of the most common. In this paper, we present a computational framework that allows automatic identification of the Whiteside line.The approach is based on geometric analysis of the saddle shape of the intercondylar fossa to extract the principal line in the AP direction. A plane parallel to the frontal plane is moved in the AP direction to obtain the 2D profiles of the intercondylar fossa. Each profile is fitted to a fifth-order polynomial curve and its maximum curvature point computed. The point set collected across all the profiles is then processed to compute the principal direction. The 2D profile-fitting and 3D line-fitting residual errors were analyzed to study the relationship between the intercondylar fossa aspect and the nominal saddle surface. The method was validated using femur specimens from elderly subjects reconstructed from CT scans. The repeatability of the method was evaluated across five different femur surface resolutions.For comparison, three expert orthopaedic surgeons identified, by virtual palpation, the Whiteside line on the same 3D femur models. The repeatability (median angular error) of the Whiteside lines computed by the automated method and by manual virtual palpation, was approximately 1.0 and 3.5 , respectively. The angular skew error between the two axes, measured on the axial plane, averaged approximately 4.00 (SD: 2.64 ) with no statistical difference. The automated method therefore proved more reproducible and was in agreement with the manual method. We conclude that operatorindependent methods, such the one presented in this paper, can be favorably introduced into orthopaedic surgical planning systems.

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

Cited by 37 publications

References 32 publications

Navigation of total knee arthroplasty: rotation of components and clinical results in a prospectively randomized study

Navigation of total knee arthroplasty: rotation of components and clinical results in a prospectively randomized study

A computed tomography based study on rotational alignment accuracy of the femoral component in total knee arthroplasty using computer-assisted orthopaedic surgery

Determination of the Whiteside line on femur surface models by fitting high-order polynomial functions to cross-section profiles of the intercondylar fossa

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