Presence of rotational errors in long leg radiographs after total knee arthroplasty and impact on measured lower limb and component alignment

Maderbacher, Günther; Baier, Christel; Benditz, Achim; Wagner, Ferdinand; Greimel, Felix; Grifka, Joachim; Keshmiri, Armin

doi:10.1007/s00264-017-3408-3

Cited by 35 publications

(33 citation statements)

References 27 publications

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“…(mLPFA), the mechanical lateral distal femur angle (mLDFA), the mechanical medial proximal tibia angle (mMPTA), the mechanical lateral distal tibia angle (mLDTA), and the mechanical tibio-femoral angle, while vice-versa internal rotation decreased all parameters. [5][6][7][8][9] To overcome these difficulties a precision radiograph frame was introduced, which however, is unpractical and therefore usually not used in daily practice. 10,11 As present, malrotation of the lower limb could not be assessed in long-leg radiographs until recently, a calculation method was introduced which allows to determine rotation of the lower limb in radiographs by measuring the extent of overlap of the proximal fibula.…”

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confidence: 99%

Lower Limb Malrotation Is Regularly Present in Long-Leg Radiographs Resulting in Significant Measurement Errors

et al. 2019

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Weight-bearing long-leg radiographs are commonly used in orthopaedic surgery. Measured parameters, however, change when radiographs are conducted in different rotational positions of the leg. It was hypothesized that rotational errors are regularly present in long-leg radiographs resulting in wrong measurements. In 100 consecutive long-leg radiographs conducted according to the method of Paley, rotation was assessed by fibular overlap. Angular parameters in radiographs (mechanical lateral proximal femoral angle (mLPFA), mechanical lateral distal femoral angle (mLDFA), angle between the anatomical and mechanical femoral axis (AMA), mechanical medial proximal tibia angle (mMPTA), mechanical lateral distal tibial angle (mLDTA), and the mechanical femoral and tibial axis (mFA–mTA) were measured and deviations related to malrotation calculated. An average internal rotation of 8 degrees was found in lower limbs showing a range between 29 degrees of internal and 22 degrees of external rotation. As a result, mean differences before and after rotational correction for measured parameters (mLPFA, mLDFA, AMA, mMPTA, mLDTA, mFA–mTA) ranged between 0.4 and 1.7 degrees (−2.1; 5.6 95% confidence interval [CI]). In conclusion, malrotation of lower limbs is regularly present in long-leg radiographs. As all measured parameters are influenced by malrotation, correct lower limb rotation needs to be verified.

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Lower Limb Malrotation Is Regularly Present in Long-Leg Radiographs Resulting in Significant Measurement Errors

et al. 2019

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“…14 This protocol is very time-consuming and impractical, while this method heavily relies on the skillset of each practitioner. 18 The Paley and Herzenberg protocol is prone to non-reproducible radiographs, which relies on the skillset of different X-ray technicians to rotate the knee (using the patellae) the same way in clinical care. 27 Also, patellar malalignment is quite common in arthritic knees, especially in cases of varus deformities.…”

Section: Discussionmentioning

confidence: 99%

“…17 The Paley and Herzenberg protocol is even more difficult in cases of total knee arthroplasties, with HKA measurement errors up to 3.5°. 18 This was probably caused by postoperative swelling and misleading surgical incisions, while technicians had difficulties to exactly centre the patella. Another important finding of this study is the overall average internal rotation of the lower limbs on WLRs, as the patella is located slightly lateral.…”

Section: Discussionmentioning

confidence: 99%

“…Centring the patella as instructed in the Paley and Herzenberg protocol requires an internally rotated lower limb. 18 WLR acquisition guidelines should focus on eliminating leg rotation to minimize the possible effect of knee flexion and account for the mean tibial rotation. It should deliver reproducible radiographs while being quick and easy to perform by X-ray technicians with fixed positioning for the feet and leg rotation.…”

Section: Discussionmentioning

confidence: 99%

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The need for a standardized whole leg radiograph guideline: The effects of knee flexion, leg rotation, and X-ray beam height

Nguyen

Gielis

Egmond

et al. 2021

Journal of Cartilage & Joint Preservation

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Introduction: Lower limb malalignment is a major risk factor for knee osteoarthritis (OA) and is mainly diagnosed using the Hip Knee Ankle Angle (HKA). Therefore, accurate HKA measurements are indispensable. Objectives: This study aimed to research the effects of knee flexion, leg rotation, and X-ray beam height on the accuracy of the HKA measurement. To convert our findings into a guideline for obtaining whole leg radiographs (WLR) in favor of accuracy and reproducibility. Methods: An in vitro experiment was designed using sawbones (in 5°varus) of the whole lower limb, fixated in different leg rotation angles, knee flexion angles, and three different X-ray beam heights. Results: The HKA measurement error was 1°per 20°of leg rotation without flexion ( P < .01). When 5°of flexion was added, the HKA measurement error was 0.8°per 20°rotation ( P < .01 ). With 15°knee flexion, the HKA measurement error became 4°per 20°rotation ( P < .01 ). Varying X-ray beam heights of 5cm ( P = .959) and 10 cm ( P = .967) did not cause any significant measurement errors. Conclusion:This study showed that leg rotation alone (without knee flexion) can lead to clinically relevant measurement errors when exceeding 9°. When there is 15°of knee flexion and 10°leg rotation the error becomes approximately 2°. Varying X-ray beam heights within a range of 10 cm does not affect the accuracy. Based on these findings, we propose guidelines for system setup and patient positioning during a WLR that is easy to apply and aims at minimizing errors when measuring the HKA.

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“…Regarding the tibia, the angle called "tibial angle" as well is the equivalent of the so-called "tibial sloping". This angle is an anatomical angle on that sagittal plane, which is formed between a tangent line at the base of the tibial component and a sagittal tibial anatomical line that is formed by connecting the furthest point of the center of the tibial shaft with a point located 10 cm under the knee joint, in the middle of the tibial shaft [3,[9][10][11][12][13].…”

Section: The Sagittal Anatomical and Mechanical Axis Of The Tibiamentioning

confidence: 99%

Postoperative TKA alignment in sagittal and axial plane, a systematic review

Creţu

Dragosloveanu

Cotor

et al. 2018

Romanian Journal of Orthopaedic Surgery and Traumatology

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The aim of this paper was to review the existing described methods for measuring postoperative TKA alignment in sagittal and axial plane and to review the existing literature regarding the axial plane evaluation with the use of the computer tomography. The most frequent mistakes when positioning the total knee arthroplasty (TKA) components are done in the axial plane, so it is necessary to know what the limits of the radiographic evaluation are and, for this evaluation, the CT scan is the most valuable in assessing the rotation of the components.

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Presence of rotational errors in long leg radiographs after total knee arthroplasty and impact on measured lower limb and component alignment

Cited by 35 publications

References 27 publications

Lower Limb Malrotation Is Regularly Present in Long-Leg Radiographs Resulting in Significant Measurement Errors

Lower Limb Malrotation Is Regularly Present in Long-Leg Radiographs Resulting in Significant Measurement Errors

The need for a standardized whole leg radiograph guideline: The effects of knee flexion, leg rotation, and X-ray beam height

Postoperative TKA alignment in sagittal and axial plane, a systematic review

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