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Predicting translational deformity following opening-wedge osteotomy for lower limb realignment.

Barksfield RC, Monsell FP - Strategies Trauma Limb Reconstr (2015)

Bottom Line: A simulated model was developed using TraumaCad online digital software suite (Brainlab AG, Germany).Osteotomies were simulated in the distal femur, proximal tibia and distal tibia for nine sets of lower limb scanograms at incremental distances from the CORA and the resulting translational deformity recorded.There was excellent agreement between the predictive algorithm and simulated translational deformity for all nine simulations (correlation coefficient 0.93-0.99, p < 0.0001).

View Article: PubMed Central - PubMed

Affiliation: Bristol Royal Hospital for Children, Paul O'Gorman Building, Upper Maudlin Street, Bristol, BS2 8BJ, UK. rcbarksfield@hotmail.com.

ABSTRACT
An opening-wedge osteotomy is well recognised for the management of limb deformity and requires an understanding of the principles of geometry. Translation at the osteotomy is needed when the osteotomy is performed away from the centre of rotation of angulation (CORA), but the amount of translation varies with the distance from the CORA. This translation enables proximal and distal axes on either side of the proposed osteotomy to realign. We have developed two experimental models to establish whether the amount of translation required (based on the translation deformity created) can be predicted based upon simple trigonometry. A predictive algorithm was derived where translational deformity was predicted as 2(tan α × d), where α represents 50 % of the desired angular correction, and d is the distance of the desired osteotomy site from the CORA. A simulated model was developed using TraumaCad online digital software suite (Brainlab AG, Germany). Osteotomies were simulated in the distal femur, proximal tibia and distal tibia for nine sets of lower limb scanograms at incremental distances from the CORA and the resulting translational deformity recorded. There was strong correlation between the distance of the osteotomy from the CORA and simulated translation deformity for distal femoral deformities (correlation coefficient 0.99, p < 0.0001), proximal tibial deformities (correlation coefficient 0.93-0.99, p < 0.0001) and distal tibial deformities (correlation coefficient 0.99, p < 0.0001). There was excellent agreement between the predictive algorithm and simulated translational deformity for all nine simulations (correlation coefficient 0.93-0.99, p < 0.0001). Translational deformity following corrective osteotomy for lower limb deformity can be anticipated and predicted based upon the angular correction and the distance between the planned osteotomy site and the CORA.

No MeSH data available.


Related in: MedlinePlus

Demonstration of where an opening-wedge osteotomy is performed at the CORA, no translation is necessary in order to correct the axis of deformity (a). Where the osteotomy is at in an alternative position to the CORA, translation is obligatory if the axis of deformity is to be realigned (b)
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Fig2: Demonstration of where an opening-wedge osteotomy is performed at the CORA, no translation is necessary in order to correct the axis of deformity (a). Where the osteotomy is at in an alternative position to the CORA, translation is obligatory if the axis of deformity is to be realigned (b)

Mentions: The predictive algorithm was developed using a simplified model comprising of a CORA at the intersection of a proximal anatomical axis and a distal anatomical axis. The angle subtended at the intersection of these axes was the angular correction needed. The predicted translation was calculated by resolving the model into two identical right-angled triangles. In this way, the anticipated translation would be 2(tan α × d), where α represents 50 % of the desired angular correction, and d is the distance of the desired osteotomy site from the CORA (Figs. 1, 2).Fig. 1


Predicting translational deformity following opening-wedge osteotomy for lower limb realignment.

Barksfield RC, Monsell FP - Strategies Trauma Limb Reconstr (2015)

Demonstration of where an opening-wedge osteotomy is performed at the CORA, no translation is necessary in order to correct the axis of deformity (a). Where the osteotomy is at in an alternative position to the CORA, translation is obligatory if the axis of deformity is to be realigned (b)
© Copyright Policy - OpenAccess
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4666231&req=5

Fig2: Demonstration of where an opening-wedge osteotomy is performed at the CORA, no translation is necessary in order to correct the axis of deformity (a). Where the osteotomy is at in an alternative position to the CORA, translation is obligatory if the axis of deformity is to be realigned (b)
Mentions: The predictive algorithm was developed using a simplified model comprising of a CORA at the intersection of a proximal anatomical axis and a distal anatomical axis. The angle subtended at the intersection of these axes was the angular correction needed. The predicted translation was calculated by resolving the model into two identical right-angled triangles. In this way, the anticipated translation would be 2(tan α × d), where α represents 50 % of the desired angular correction, and d is the distance of the desired osteotomy site from the CORA (Figs. 1, 2).Fig. 1

Bottom Line: A simulated model was developed using TraumaCad online digital software suite (Brainlab AG, Germany).Osteotomies were simulated in the distal femur, proximal tibia and distal tibia for nine sets of lower limb scanograms at incremental distances from the CORA and the resulting translational deformity recorded.There was excellent agreement between the predictive algorithm and simulated translational deformity for all nine simulations (correlation coefficient 0.93-0.99, p < 0.0001).

View Article: PubMed Central - PubMed

Affiliation: Bristol Royal Hospital for Children, Paul O'Gorman Building, Upper Maudlin Street, Bristol, BS2 8BJ, UK. rcbarksfield@hotmail.com.

ABSTRACT
An opening-wedge osteotomy is well recognised for the management of limb deformity and requires an understanding of the principles of geometry. Translation at the osteotomy is needed when the osteotomy is performed away from the centre of rotation of angulation (CORA), but the amount of translation varies with the distance from the CORA. This translation enables proximal and distal axes on either side of the proposed osteotomy to realign. We have developed two experimental models to establish whether the amount of translation required (based on the translation deformity created) can be predicted based upon simple trigonometry. A predictive algorithm was derived where translational deformity was predicted as 2(tan α × d), where α represents 50 % of the desired angular correction, and d is the distance of the desired osteotomy site from the CORA. A simulated model was developed using TraumaCad online digital software suite (Brainlab AG, Germany). Osteotomies were simulated in the distal femur, proximal tibia and distal tibia for nine sets of lower limb scanograms at incremental distances from the CORA and the resulting translational deformity recorded. There was strong correlation between the distance of the osteotomy from the CORA and simulated translation deformity for distal femoral deformities (correlation coefficient 0.99, p < 0.0001), proximal tibial deformities (correlation coefficient 0.93-0.99, p < 0.0001) and distal tibial deformities (correlation coefficient 0.99, p < 0.0001). There was excellent agreement between the predictive algorithm and simulated translational deformity for all nine simulations (correlation coefficient 0.93-0.99, p < 0.0001). Translational deformity following corrective osteotomy for lower limb deformity can be anticipated and predicted based upon the angular correction and the distance between the planned osteotomy site and the CORA.

No MeSH data available.


Related in: MedlinePlus