How to avoid unintended valgus alignment in distal femoral derotational osteotomy for treatment of femoral torsional malalignment - a concept study

Imhoff, Florian B.; Scheiderer, Bastian; Zakko, Philip; Obopilwe, Elifho; Liska, Franz; Imhoff, Andreas B.; Mazzocca, Augustus D.; Arciero, Robert A.; Beitzel, Knut

doi:10.1186/s12891-017-1904-7

Cited by 12 publications

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References 26 publications

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“…Trigonometric calculations showed varus producing effects after a simple internal rotation of the proximal limb when the cutting plane was 90 degrees to the proximal virtual anatomical axis (regarding the greater trochanter) [ 22 ]. Table 2 shows the change of AMA at a defined torsion angle, which is independent from limb length, (formula is shown in Fig.…”

Section: Resultsmentioning

confidence: 99%

“…The guide was aligned parallel to the virtual anatomic axis from a coronal view and parallel to the virtual anatomical axis from a sagittal view. The virtual anatomical axis is a line from the middle of the proximal shaft at the greater trochanter to the middle of the distal shaft at the assumed height of the cutting plane, on a frontal and a sagittal view [ 22 ]. For rotational control, two 2.5 mm k-wires were inserted from anterior to posterior, one proximal to the assumed osteotomy and one on the distal side.…”

Section: Methodsmentioning

confidence: 99%

“…No actual lengths are needed when calculations are done with at least two known angles in a perpendicular triangle (Fig. 5 in Appendix ) [ 22 ].

Fig.…”

Section: Appendixmentioning

confidence: 99%

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Single cut distal femoral osteotomy for correction of femoral torsion and valgus malformity in patellofemoral malalignment - proof of application of new trigonometrical calculations and 3D-printed cutting guides

Imhoff

Schnell

Magaña

et al. 2018

BMC Musculoskelet Disord

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BackgroundThe purpose of this study was to perform a derotational osteotomy at the distal femur, as is done in cases of patellofemoral instability, and demonstrate the predictability of three-dimensional (3D) changes on axes in a cadaveric model by the use of a new mathematical approach.MethodsTen human cadaveric femurs, with increased antetorsion, underwent a visually observed derotational osteotomy at the distal femur by 20°, as is commonly done in clinics. For surgery, a single cut osteotomy with a defined cutting angle was calculated and given using a simple 3D-printed cutting guide per specimen, based on a newly-created trigonometrical model. To simulate post-operative straight frontal alignment in a normal range, a goal for the mechanical lateral distal femur angle (mLDFA) was set to 87.0° for five specimens (87-goal group) and 90.0° for five specimens (90-goal group). Specimens underwent pre- and post-operative radiographic analysis with CT scan for torsion and frontal plane x-ray for alignment measurements of mLDFA and anatomical mechanical angle (AMA).ResultsPerformed derotation showed a mean of 19.69° ±1.08°SD (95% CI: 18.91° to 20.47°). Regarding frontal alignment, a mean mLDFA of 86.9° ±0.66°SD (87-goal-group) and 90.42° ±0.25° SD (90-goal group), was observed (p = 0.008). Overall, the mean difference between intended mLDFA-goal and post-operatively achieved mLDFA was 0.14° ±0.56° SD (95% CI: -0.26° to 0.54°).ConclusionA preoperative calculated angle for single cut derotational osteotomy at the distal femur leads to a clinically precise post-operative result on torsion and frontal alignment when using this approach.

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Section: Resultsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

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Single cut distal femoral osteotomy for correction of femoral torsion and valgus malformity in patellofemoral malalignment - proof of application of new trigonometrical calculations and 3D-printed cutting guides

Imhoff

Schnell

Magaña

et al. 2018

BMC Musculoskelet Disord

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“…Nelitz et al [26] have proposed that if the coronal plane is in varus, the osteotomy must be performed in the distal metaphysis, and like in this case study, if the coronal alignment is neutral, a transverse osteotomy on the shaft of the femur must be done. However, Imhoff et al demonstrated, in a cadaveric study, the importance of the orientation of the cut in the distal femur to avoid changes in the coronal orientation of the limb, when a distal femoral derotational osteotomy is performed [27]. More importantly, by a single cut in the distal femur, the coronal and the rotational problem of the patient can be addressed by choosing the patient-specific oblique cut [28]; these promising results must be validated in the operating room.…”

Section: Discussionmentioning

confidence: 99%

Retrograde Intramedullary Nail Fixation for Derotational Femoral Osteotomy for Recurrent Femoropatellar Instability

Barahona

Zamorano

Barrientos

et al. 2019

Case Reports in Orthopedics

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Axial alignment of the femur and tibia is often misdiagnosed in patients with patellofemoral stability problems. Femoral torsion is critical for patellofemoral biomechanics, so it must be evaluated in every patient before the plan of surgery is decided. This case describes a femoral derotational osteotomy due to excessive internal torsion of the femur fixed with a retrograde femoral nail. This type of fixation provides a biomechanical advantage compared to plates. At the two-year follow-up, the patient achieved excellent results, reaching a functional score of 91 points on the Lysholm scale. Derotational femoral osteotomy should be considered in patellofemoral pathology, and a retrograde femoral nail is a valid fixation method for this surgery.

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“…However, other authors propose to perform the osteotomy perpendicular to the femoral mechanical axis [13], possibly with less influence on the postoperative mechanical leg axis. There are different other attempts for preoperative planning of the correct osteotomy plane in femoral rotational osteotomies [14][15][16]. Nonetheless, implementation of the preoperative planning into the surgical situation can be challenging, wherefore some deviation from the planning is likely in most cases.…”

Section: Introductionmentioning

confidence: 99%

The impact of mal-angulated femoral rotational osteotomies on mechanical leg axis: a computer simulation model

Jud

Vlachopoulos

Häller

et al. 2020

BMC Musculoskelet Disord

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Background: Subtrochanteric or supracondylar femoral rotational osteotomies are established surgical treatments for femoral rotational deformities. Unintended change of the mechanical leg axis is an identified problem. Different attempts exist to plan a correct osteotomy plane, but implementation of the preoperative planning into the surgical situation can be challenging. Goal of this study was to identify the critical threshold of mal-angulation of the osteotomy plane and of femoral rotation that leads to a relevant deviation of the postoperative mechanical leg axis using a computer simulation approach. Methods: Three-dimensional (3D) surface models of the lower extremity of two patients (Model 1: 42°femoral antetorsion; Model 2: 6°femoral retrotorsion) were generated from computed tomography data. First, baseline subtrochanteric and supracondylar rotational osteotomies, perpendicular to the femoral mechanical axis were simulated. Afterwards, mal-angulated osteotomies in sagittal and frontal plane followed by different degrees of rotation were simulated and frontal mechanical axis was analyzed. Results: 400 mal-angulated osteotomies have been simulated. Mal-angulation of ±30°with 30°rotation showed maximum deviation from preoperative mechanical axis in subtrochanteric osteotomies (4.0°± 0.4°) and in supracondylar osteotomies (12.4°± 0.8°). Minimal mal-angulation of 15°in sagittal plane in subtrochanteric osteotomies and mal-angulation of 10°in sagittal plane in supracondylar osteotomies altered the mechanical axis by > 2°. Mal-angulation in sagittal plane showed higher deviations of the mechanical axis (up to 12.4°± 0.8°), than in frontal plane mal-angulation (up to 4.0°± 1.9°). Conclusion: A femoral rotational osteotomy, perpendicular to the femoral mechanical axis, has no considerable influence on the mechanical leg axis. However, mal-angulation of femoral rotational osteotomies showed relevant changes of the mechanical leg axis. In supracondylar respectively subtrochanteric procedures, mal-angulation of only 10°in combination with already 15°of femoral rotation respectively mal-angulation of 15°in combination with 30°of femoral rotation, can lead to a relevant postoperative mechanical leg axis deviation of more than 2°, wherefore these patients probably would benefit from the use of navigation aids.

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How to avoid unintended valgus alignment in distal femoral derotational osteotomy for treatment of femoral torsional malalignment - a concept study

Cited by 12 publications

References 26 publications

Single cut distal femoral osteotomy for correction of femoral torsion and valgus malformity in patellofemoral malalignment - proof of application of new trigonometrical calculations and 3D-printed cutting guides

Single cut distal femoral osteotomy for correction of femoral torsion and valgus malformity in patellofemoral malalignment - proof of application of new trigonometrical calculations and 3D-printed cutting guides

Retrograde Intramedullary Nail Fixation for Derotational Femoral Osteotomy for Recurrent Femoropatellar Instability

The impact of mal-angulated femoral rotational osteotomies on mechanical leg axis: a computer simulation model

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