Linear influence of distal femur osteotomy on the Q-angle: one degree of varization alters the Q-angle by one degree.
Knee Surg Sports Traumatol Arthrosc
; 29(2): 540-545, 2021 Feb.
Article
en En
| MEDLINE
| ID: mdl-32274549
ABSTRACT
PURPOSE:
The effect of a distal femur varization osteotomy on patellofemoral biomechanics in genu valgum is unknown. The purpose of this study was to quantify the influence of frontal leg axis correction on the Q-angle with a novel three-dimensional (3-D) measurement method.METHODS:
3-D surface models of ten lower extremities were generated using patient computed tomography (CT) data. The preoperative 3-D Q-angle was measured using a novel defined and validated 3-D measurement method. Biplanar supracondylar osteotomies were simulated with different degrees of varus correction (from 1° to 15°) in one-degree steps beginning from the preoperative valgus deformity, resulting in a total of 150 simulations. Additionally, mechanical leg axis and 3-D Q-angle measurements were performed on 3-D surface models of the postoperative CT scans of the same individuals. Further, pre- and postoperative TT-TG distance was measured.RESULTS:
Mean preoperative Q-angle was 15.8 ± 3.9° (range 10°-21.4°) with a mean preoperative mechanical leg axis of 6.5° ± 2.4 valgus (range 3.8°-11.6° valgus). The Q-angle changed linearly 0.9 ± 0° per 1° of varization. No difference was detected between simulated 3-D Q-angles and effectively corrected postoperative values (n.s.). TT-TG distance changed irregularly and minimally, and with no correlation to the degree of varization.CONCLUSION:
Distal femur varization osteotomy has a linear effect on the Q-angle with a change of 1° per 1° of varization. The difference in TT-TG distance was mainly due to an unintentional rotational component implemented during surgery.Palabras clave
Texto completo:
1
Banco de datos:
MEDLINE
Asunto principal:
Osteotomía
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Genu Valgum
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Fémur
Tipo de estudio:
Prognostic_studies
Límite:
Adult
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Humans
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Middle aged
Idioma:
En
Año:
2021
Tipo del documento:
Article