Determining the rotation of thefemoral and tibial components in total knee arthroplasty: A computer tomography technique

Berger, Richard A.; Crossett, Lawrence S.

doi:10.1016/s1048-6666(98)80022-0

Cited by 27 publications

(30 citation statements)

References 15 publications

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“…However, with the recent widespread introduction of threedimensional imaging and CAN, there is additional focus on sagittal and axial alignment [19,30,77,88]. While postoperative CT is routinely acquired to evaluate component rotation in patients with patellar maltracking issues [6], the costly nature of routine postoperative scanning is prohibitive in large-scale studies. Although sagittal alignment is undoubtedly important in TKA as well, parameters of ideal orientation have been studied far less than in the coronal or axial planes [77].…”

Section: Discussionmentioning

confidence: 99%

Improved Accuracy of Alignment With Patient-specific Positioning Guides Compared With Manual Instrumentation in TKA

DeClaire

Berend

et al. 2012

Clinical Orthopaedics &Amp; Related Research

283

242

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Background Coronal malalignment occurs frequently in TKA and may affect implant durability and knee function. Designed to improve alignment accuracy and precision, the patient-specific positioning guide is predicated on restoration of the overall mechanical axis and is a multifaceted new tool in achieving traditional goals of TKA. Questions/purposes We compared the effectiveness of patient-specific positioning guides to manual instrumentation with intramedullary femoral and extramedullary tibial guides in restoring the mechanical axis of the extremity and achieving neutral coronal alignment of the femoral and tibial components. Methods We retrospectively reviewed 569 TKAs performed with patient-specific positioning guides and 155 with manual instrumentation by two surgeons using postoperative long-leg radiographs. For all patients, we assessed the zone in which the overall mechanical axis passed through the knee, and for one surgeon's cases (105 patient-specific positioning guide, 55 manual instrumentation), we also measured the hip-knee-ankle angle and the individual component angles with respect to their mechanical axes. Results The overall mechanical axis passed through the central third of the knee more often with patient-specific positioning guides (88%) than with manual instrumentation (78%). The overall mean hip-knee-ankle angle for patient-specific positioning guides (180.6°) was similar to manual instrumentation (181.1°), but there were fewer ± 3°hip-knee-ankle angle outliers with patient-specific positioning guides (9%) than with manual instrumentation (22%). The overall mean tibial (89.9°versus 90.4°) and femoral (90.7°versus 91.3°) component angles were closer to neutral with patient-specific positioning guides than with manual instrumentation, but the

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Section: Discussionmentioning

confidence: 99%

Improved Accuracy of Alignment With Patient-specific Positioning Guides Compared With Manual Instrumentation in TKA

DeClaire

Berend

et al. 2012

Clinical Orthopaedics &Amp; Related Research

283

242

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“…We gained knowledge of varus/valgus alignment and rotational malalignment by reading the early work of Berger et al [3][4][5] However, an instructional course conducted by Vince opened our minds and caused us to turn our attention to the rotational malalignment of prosthetic components, especially the tibial component. 6 The incorrect rotational orientation of a system inevitably leads to a painful, loose, and poorly positioned prosthesis and a dissatisfied patient (ie, an unsatisfactory result).…”

Section: 2mentioning

confidence: 99%

Total Knee Arthroplasty Malalignment: Myth or Reality?

Spinarelli¹,

Maccagnano²,

Moretti³

2015

Orthopedics

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Sixteen years ago, when we began studying the realm of knee prostheses, the focus was on new materials, posterior stabilized vs cruciate retaining, whether to perform patella resurfacing, wear, and varus/valgus alignment. At that point, we had not heard of rotational alignment of the prosthetic components. However, with time, we began studying alignment in the frontal and sagittal planes, considering it essential for a good functional, durable outcome.When knee arthroplasty began, the major focus was on axial alignment. According to the literature, a tibial varus/valgus malalignment of greater than 3° may change the distribution of load and shear forces between medial and lateral compartments. 1,2We gained knowledge of varus/valgus alignment and rotational malalignment by reading the early work of Berger et al. [3][4][5] However, an instructional course conducted by Vince opened our minds and caused us to turn our attention to the rotational malalignment of prosthetic components, especially the tibial component. 6The incorrect rotational orientation of a system inevitably leads to a painful, loose, and poorly positioned prosthesis and a dissatisfied patient (ie, an unsatisfactory result). Anterior knee pain continues to be a relatively common finding after total knee replacement, having a reported incidence of 10% to 20%. Tibial malrotation is responsible for anterior-posterior translation. Furthermore, it is possible to observe a decreasing of patellofemoral shear forces due to femoral internal rotation and polyethylene component impingement. The malalignment of prosthetic components is responsible for patellofemoral maltracking. Various computer models and cadaveric studies have confirmed the alterations of the patellar biomechanics. 8,9 Computed tomography has clearly established the relationship between patellar complications (eg, subluxation and dislocation) and patellar component failure with component malrotation. The association between malrotation and the presence of anterior knee pain has not been well documented. Relative internal rotation of the tibial component effectively increases the Q angle and changes the force vector on the extensor mechanism. The abnormal stress on the patella and surrounding soft tissue could explain the anterior pain.During total knee arthroplasty, it is difficult to restore the patellofemoral joint, considering its mobility and physiological tension of alar ligaments. In the normal joint, the patella is slightly lateral to the femur in full extension; when the knee is flexed, the patella is slightly medial compared with its previous position. Internal rotation of both prosthetic components increases the valgus angle value (Q angle), and sometimes the extensor compartment applies more force than the physiological condition. Internal femoral rotation may increase patellar medial tilt and medial shift. The external femoral component rotation reduces the Q angle value and causes an increase in patellar lateral tilt and lateral shift. It is possible to describe the maximal chan...

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“…The PCA is defined in a similar manner for both the femur and tibia; the femoral PCA is referred to here as the fPCA and the tibial PCA will be the tPCA. The average rotation between the STEA and fPCA is 0.3° of internal rotation in women and 3.5° of internal rotation in men [12,13]. TKA femoral components are often designed with a built-in external rotation of approximately 3° to compensate for this fact and easily restore rotation of the femoral articulating surface to its position in the native knee.…”

Section: Tka Component Alignmentmentioning

confidence: 99%

“…This is due to the large variety of implant designs that were received as part of the testing described here. Two [12] major surgical parameters were assessed in this study: component alignment and laxity due to soft tissue balancing.…”

Section: Factors Related To Tka Wearmentioning

confidence: 99%

“…This is the traditional method; however, since the tubercle is rotated externally relative to the tibial plateau, it has been shown to create a tendency for external rotation [18]. An analysis of patients has shown that, on average, the tibial tubercle is 18 degrees external to an antero-posterior line drawn through the geometric center of the tibia [12].…”

Section: Component Sub-optimal Alignmentmentioning

confidence: 99%

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Total Knee Arthroplasty Wear Is Caused by Malrotation and Excessive Laxity

Woodard¹

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Determining the rotation of thefemoral and tibial components in total knee arthroplasty: A computer tomography technique

Cited by 27 publications

References 15 publications

Improved Accuracy of Alignment With Patient-specific Positioning Guides Compared With Manual Instrumentation in TKA

Improved Accuracy of Alignment With Patient-specific Positioning Guides Compared With Manual Instrumentation in TKA

Total Knee Arthroplasty Malalignment: Myth or Reality?

Total Knee Arthroplasty Wear Is Caused by Malrotation and Excessive Laxity

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