Unexpected angular or rotational deformity after corrective osteotomy

Lee, Seung Yeol; Jeong, Jin-Yong; Lee, Kyung-Ho; Chung, Chin Youb; Lee, Kyoung Min; Kwon, Soon Sun; Choi, Young Rok; Kim, Tae Kyun; Lee, Jeong Ik; Lee, Jehee; Park, Moon Seok

doi:10.1186/1471-2474-15-175

Cited by 20 publications

(22 citation statements)

References 12 publications

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“…Unfortunately, while successful in treating antetorsion, rotational osteotomy carries a high risk of change of axis alignment. 16 , 20 Paley and Herzenberg 22 showed a way to address the frontal axis combined with torsion for the correction of deformities. Their mathematical approach is complex and contains information that can be adapted to different tubular bones.…”

Section: Discussionmentioning

confidence: 99%

“…Orientations, plane views, and anatomic references due to rotation are elementary and not easily transferable into the operating room. 16 With regard to derotational osteotomy in cases of patellofemoral instability, unintended axis malalignment such as postoperative increased valgus contradicts the initial purpose of treating patellofemoral malalignment. The presence of valgus malalignment is known to be an additional risk factor in patellofemoral instability cases, independent from maltorsion.…”

Section: Discussionmentioning

confidence: 99%

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Derotational Osteotomy of the Distal Femur for the Treatment of Patellofemoral Instability Simultaneously Leads to the Correction of Frontal Alignment: A Laboratory Cadaveric Study

Imhoff

Beitzel

Zakko

et al. 2018

Orthopaedic Journal of Sports Medicine

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Background:Derotational osteotomy of the distal femur allows the anatomic treatment of patellofemoral maltracking due to increased femoral antetorsion. However, such rotational osteotomy procedures have a high potential of intended/unintended changes of frontal alignment.Purpose/Hypothesis:The purpose of this study was to perform derotational osteotomy of the distal femur and to demonstrate the utility of a novel trigonometric approach to address 3-dimensional (3D) changes on 2-dimensional imaging (axial computed tomography [CT] and frontal-plane radiography). The hypothesis was that 1-step single-cut osteotomy can simultaneously correct torsion and frontal alignment based on preoperatively calculated cutting angles.Study Design:Controlled laboratory study.Methods:Eight human cadaveric whole legs (4 lower limb torsos) underwent derotational osteotomy of the distal femur of 20°. A straight leg axis, determined as a mechanical femorotibial angle (mFTA) of 0°, was chosen as a goal for postoperative frontal alignment. The inclination of the cutting angle from the lateral view was calculated individually for each cadaveric leg and was represented by a simple 3D-printed cutting guide for surgery. Specimens underwent CT for the measurement of torsion, while the frontal leg axis was determined on an upright radiograph preoperatively and postoperatively. Preoperative and postoperative angles were compared with the mathematical prediction model.Results:The preoperative mFTA ranged from –3.9° (valgus) to +3.4° (varus) (mean, –0.2° ± 2.6°). A postoperative mean mFTA of 0.37° ± 0.69° (95% CI, –0.22° to 0.95°) was achieved (P = .01). Derotation showed a mean of 19.1° ± 2.1° (95% CI, 17.3°-20.8°). The oblique cutting plane for the correction of valgus legs showed a mean of 5.9° ± 6.8° and, for the correction of varus legs, a mean of –10.0° ± 4.5° projected on the perpendicular plane to the virtual anatomic shaft axis from the sagittal view.Conclusion:Single-cut distal femoral osteotomy can be performed to simultaneously address rotational as well as frontal alignment using a preoperatively defined oblique cut, as determined by the presented reproducible calculation model.Clinical Relevance:This study adds important knowledge to the technique of derotational osteotomy. This approach provides an individual, oblique single cut for the correction of torsion and frontal axis within a clinically insignificant margin. Simplified tables for calculation and a surgical reference make this model reproducible and safe.

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Derotational Osteotomy of the Distal Femur for the Treatment of Patellofemoral Instability Simultaneously Leads to the Correction of Frontal Alignment: A Laboratory Cadaveric Study

Imhoff

Beitzel

Zakko

et al. 2018

Orthopaedic Journal of Sports Medicine

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“…Lee et al showed in several computer simulations that unexpected angular or rotational deformity can occur during rotational osteotomies [ 16 ]. They stated that femoral antecurvation and femoral bowing can affect the alignment of the lower leg and that osteotomy on the anatomical shaft, proximal or distal, influences mechanical axis.…”

Section: Discussionmentioning

confidence: 99%

“…Increased valgus alignment could lead to increased lateral facet pressure and increased medial retinaculum strain [ 12 – 14 ]. In the clinical experience and with regards to previous publications, derotational osteotomies may result in unplanned frontal malalignment; thus, unintended valgus producing effects should be avoided strictly [ 11 , 15 , 16 ].…”

Section: Introductionmentioning

confidence: 99%

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

Imhoff

Scheiderer

Zakko

et al. 2017

BMC Musculoskelet Disord

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BackgroundDefining the optimal cutting plane for derotational osteotomy at the distal femur for correction of torsion in cases of patellofemoral instability is still challenging. This preliminary study investigates changes of frontal alignment by a simplified trigonometrical model and demonstrates a surgical guidance technique with the use of femur cadavers. The hypothesis was that regardless of midshaft bowing, a cutting plane perpendicular to the virtual anatomic shaft axis avoids unintended valgus malalignment due to derotation.MethodsA novel mathematical model, called the Pillar-Crane-Model, was developed to forecast changes on frontal alignment of the femur when a perpendicular cutting plane to the virtual anatomical shaft was chosen. As proof of concept, eight different torsion angles were assessed on two human cadaver femora (left and right). A single cut distal femoral osteotomy perpendicular to the virtual anatomical shaft was performed. Frontal plane alignment (mLDFA, aLDFA, AMA) was radiographically analyzed before and after rotation by 0°, 10°, 20°, and 30°. Measurements were compared to the model.ResultsThe trigonometrical equation from the Pillar-Crane-Model provides mathematical proof that slight changes into varus occur, seen by an increase in AMA and mLDFA, when the cutting plane is perpendicular to the virtual anatomical shaft axis. A table with standardized values is provided. Exemplarily, the specimens showed a mean increase of AMA from 4.8° to 6.3° and mLDFA from 85.2° to 86.7 after derotation by 30°. Throughout the derotation procedure, aLDFA remained at 80.4° ± 0.4°SD.ConclusionsWith the use of this model for surgical guidance and anatomic reference, unintended valgus changes on frontal malalignment can be avoided. When the cutting plane is considered to be perpendicular to the virtual anatomical shaft from a frontal and lateral view, a slight increase of mLDFA results when a derotational osteotomy of the distal femur is performed.

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“…Femoral rotational deformities with excessive antetorsion or retrotorsion are frequently seen in patients with femoroacetabular impingement [1,2], hip dysplasia [3,4] or patellofemoral instability [5,6]. Established treatment options are free-hand subtrochanteric or supracondylar femoral rotational osteotomies [7][8][9], bearing the risk of unintended changes in mechanical leg axis [10,11]. Furthermore, a computer model study by Nelitz M et al [12] showed a tendency to varus angulation in proximal-and a tendency to valgus angulation in distal femoral external-rotational osteotomies.…”

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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Unexpected angular or rotational deformity after corrective osteotomy

Cited by 20 publications

References 12 publications

Derotational Osteotomy of the Distal Femur for the Treatment of Patellofemoral Instability Simultaneously Leads to the Correction of Frontal Alignment: A Laboratory Cadaveric Study

Derotational Osteotomy of the Distal Femur for the Treatment of Patellofemoral Instability Simultaneously Leads to the Correction of Frontal Alignment: A Laboratory Cadaveric Study

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

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

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