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

Maderbacher, Günther; Matussek, J.; Greimel, Felix; Grifka, Joachim; Schaumburger, Jens; Baier, Christel; Keshmiri, Armin

doi:10.1055/s-0039-1693668

Cited by 14 publications

(27 citation statements)

References 14 publications

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“…All full-length radiographs were screened by one of the authors for excessive rotation in the coronal plane which made the radiograph unsuitable for analysis. 15 The excessive rotation was determined on radiographs by the profile of the lesser trochanter and fibular head and whether the patella was centered or medial/lateral. Digital images of the radiographs were used for measuring various radiographic parameters using the Image J image processing and analysis software (version 1.41, U.S. National Institute of Health).…”

Section: Methodsmentioning

confidence: 99%

Comparison with Navigation of a Novel Three-Step Technique for Improving Accuracy of the Distal Femoral Resection during Conventional TKA: A Case–Control Study

Mullaji

Khalifa

Shetty³

et al. 2021

J Knee Surg

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Correct placement of the femoral component in the coronal plane during primary total knee arthroplasty (TKA) is related to long-term survival. The aim of this radiographic study was to determine the accuracy of a novel three-step technique for improving the accuracy of the distal femoral cut during conventional technique and compare it with computer navigation during TKA. A total of 458 TKAs were retrospectively analyzed (178 conventional TKAs with the novel technique and 280 navigated TKAs) for postoperative femoral component coronal alignment and compared between the two groups. Mean femoral component coronal alignment was not significantly different (p = 0.314) between the two groups. There was no significant difference in the mean femoral component coronal alignment between varus and valgus knees. The number of outliers (90 ± 3 degrees) for femoral component coronal alignment was not significantly different between the two groups when assessed separately for varus and valgus deformities. The mean value of femoral component alignment using the conventional technique in knees with varus deformity <10 degrees was 88.8 degrees, in knees with varus deformity 10 to 20 degrees was 89.4 degrees, and in those with varus deformity >20 degrees was 90.2 degrees. Femoral component alignment in knees with varus <10 degrees was significantly different from those >20 degrees (p = 0.006); there was no significant difference between knees with varus <10 degrees and those with 10 to 20 degrees varus (p = 0.251), nor between 10 and 20 degrees varus knees and those with varus >20 degrees (p = 0.116). Using the novel three-step technique during conventional TKA to perform the distal femoral cut can help achieve femoral component coronal alignment comparable to the navigation technique.

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Section: Methodsmentioning

confidence: 99%

Comparison with Navigation of a Novel Three-Step Technique for Improving Accuracy of the Distal Femoral Resection during Conventional TKA: A Case–Control Study

Mullaji

Khalifa

Shetty³

et al. 2021

J Knee Surg

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“…Second, measuring mechanical axis in long-leg radiographs is susceptible to measurement errors due to lower limb malrotation [ 22 ]. A recently published study has shown a range between 29° of internal rotation and 22° of external rotation, resulting in measurement errors between 0.4° and 1.7° [ 41 ]. To minimize measurement errors, the independent examiners followed a strict measurement protocol.…”

Section: Discussionmentioning

confidence: 99%

Pros and cons of navigated versus conventional total knee arthroplasty—a retrospective analysis of over 2400 patients

Meyer

Renkawitz

Völlner

et al. 2021

Arch Orthop Trauma Surg

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Introduction Because of the ongoing discussion of imageless navigation in total knee arthroplasty (TKA), its advantages and disadvantages were evaluated in a large patient cohort. Methods This retrospective analysis included 2464 patients who had undergone TKA at a high-volume university arthroplasty center between 2012 and 2017. Navigated and conventional TKA were compared regarding postoperative mechanical axis, surgery duration, complication rates, one-year postoperative patient-reported outcome measures (PROMs) (WOMAC and EQ-5D indices), and responder rates as defined by the criteria of the Outcome Measures in Rheumatology and Osteoarthritis Research Society International consensus (OMERACT-OARSI). Results Both navigated (1.8 ± 1.6°) and conventional TKA (2.1 ± 1.6°, p = 0.002) enabled the exact reconstruction of mechanical axis. Surgery duration was six minutes longer for navigated TKA than for conventional TKA (p < 0.001). Complication rates were low in both groups with comparable frequencies: neurological deficits (p = 0.39), joint infection (p = 0.42 and thromboembolic events (p = 0.03). Periprosthetic fractures occurred more frequently during conventional TKA (p = 0.001). One-year PROMs showed excellent improvement in both groups. The WOMAC index was statistically higher for navigated TKA than for conventional TKA (74.7 ± 19.0 vs. 71.7 ± 20.7, p = 0.014), but the increase was not clinically relevant. Both groups had a similarly high EQ-5D index (0.23 ± 0.24 vs. 0.26 ± 0.25, p = 0.11) and responder rate (86.5% [256/296] vs. 85.9% [981/1142], p = 0.92). Conclusion Both methods enable accurate postoperative leg alignment with low complication rates and equally successful PROMs and responder rates one year postoperatively. Level of evidence III. Retrospective cohort study.

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“…A large heterogeneity was found among the included studies in terms of image modalities, subjects, and analyzed alignment measurements (Table 1). The included studies used different image modalities as follows: short-plane anteroposterior radiographs [35,63], weight-bearing LLR [19,36,37,49,55], LLR without weight bearing [8,25,47,56], computed tomography (CT) [21,24,26,29], navigation system [28], EOS imaging [40,58,64], weight-bearing LLR combined with EOS imaging [42], weight-bearing LLR and a helical CT [27], and short-plane knee radiographs and LLR [33].…”

Section: Study Characteristics: Image Modalities Selected Subjects and Radiographic Measurementsmentioning

confidence: 99%

“…Except Khare and Jaramez [29] (n = 10), these studies used less than five specimens or test objects [8,25,28,35,40,47,56,58,63]. Three studies used CT data from patients [21,24,26,27] and five studies used radiographs from patients retrospectively [36,37,42,49,64]. Hunt et al [19], Stricker and Faustgen [55], and Lee et al [33] obtained radiographs from patients with different rotation positions prospectively.…”

Section: Study Characteristics: Image Modalities Selected Subjects and Radiographic Measurementsmentioning

confidence: 99%

Influence of axial limb rotation on radiographic lower limb alignment: a systematic review

Ahrend

Baumgartner

Ihle

et al. 2021

Arch Orthop Trauma Surg

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Introduction The influence of limb malrotation on long-leg radiographs (LLR) is frequently discussed in literature. This systematic review aimed to describe the influence of limb rotation on alignment measurements alone and in combination with knee flexion, and determine its clinical impact. Materials and methods A literature search was conducted in June 2021 using the databases MEDLINE, Cochrane, Web of Science (Clarivate Analytics), and Embase. The search term ((radiograph OR X-ray) AND (position OR rotation) AND limb alignment) was used. Database query, record screening, and study inclusion and exclusion were performed by two reviewers independently. Experimental studies (using either specimens or synthetic bones) or clinical studies (prospective or retrospective using radiographs of patients) analyzing the influence of limb rotation on anatomic and mechanical limb alignment measurements were included. Characteristics and results of the included studies were summarized, simplified, and grouped for comparison to answer the research question. Studies were compared descriptively, and no meta-analysis was performed. Results A total of 22 studies were included showing large heterogeneity, comprising studies with cadavers, patients, and synthetic bones. Most studies (7 out of 8) reported that external rotation (ER) causes less apparent valgus and leads to more varus and internal rotation (IR) causes more valgus and leads to less varus. However, there is no consensus on the extent of rotation influencing alignment measures. Studies reported about an average change of > 2° (n = 4) and < 2° (n = 4) hip-knee-ankle angle (HKA) between 15°IR and 15°ER. There is a consensus that the impact of rotation on mechanical alignment is higher if additional sagittal knee angulation, such as knee flexion, is present. All five studies analyzing the influence of rotation combined with knee flexion (5°–15°) showed an HKA change of > 2° between 15°IR and 15°ER. Conclusion Malrotation is frequently present on LLR, possibly influencing the measured alignment especially in knees with extension deficit. Surgeons must consider this when measuring and treating deformities (high tibial osteotomy or total knee arthroplasties), and analyzing surgical outcomes. Especially in patients with osteoarthritis with knee extension deficits or postoperative swelling, the effect of malrotation is significantly greater.

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

Cited by 14 publications

References 14 publications

Comparison with Navigation of a Novel Three-Step Technique for Improving Accuracy of the Distal Femoral Resection during Conventional TKA: A Case–Control Study

Comparison with Navigation of a Novel Three-Step Technique for Improving Accuracy of the Distal Femoral Resection during Conventional TKA: A Case–Control Study

Pros and cons of navigated versus conventional total knee arthroplasty—a retrospective analysis of over 2400 patients

Influence of axial limb rotation on radiographic lower limb alignment: a systematic review

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