No relevant mechanical leg axis deviation in the frontal and sagittal planes is to be expected after subtrochanteric or supracondylar femoral rotational or derotational osteotomy

Abstract

Purpose The purpose of this study was to investigate if one level of corrective femoral osteotomy (subtrochanteric or supracondylar) bears an increased risk of unintentional implications on frontal and sagittal plane alignment in a simulated clinical setting. Methods Out of 100 cadaveric femora, 23 three-dimensional (3-D) surface models with femoral antetorsion (femAT) deformities (> 22° or < 2°) were investigated, and femAT normalized to 12° with single plane rotational osteotomies, perpendicular to the mechanical axis of the femur. Change of the frontal and sagittal plane alignment was expressed by the mechanical lateral distal femoral angle (mLDFA) and the posterior distal femoral angle (PDFA), respectively. The inluence of morphologic factors of the femur [centrum-collum-diaphyseal (CCD) angle and antecurvatum radius (ACR)] were assessed. Furthermore, position changes of the lesser (LT) and greater trochanters (GT) in the frontal and sagittal plane compared to the hip centre were investigated. Results Mean femoral derotation of the high-antetorsion group (n = 6) was 12.3° (range 10-17°). In the frontal plane, mLDFA changed a mean of 0.1° (− 0.06 to 0.3°) (n.s.) and − 0.3° (− 0.5 to − 0.1) (p = 0.03) after subtrochanteric and supracondylar osteotomy, respectively. In the sagittal plane, PDFA changed a mean of 1° (0.7 to 1.1) (p = 0.03) and 0.3° (0.1 to 0.7) (p = 0.03), respectively. The low-antetorsion group (n = 17) was rotated by a mean of 13.8° (10°-23°). mLDFA changed a mean of − 0.2° (− 0.5° to 0.2°) (p < 0.006) and 0.2° (0-0.5°) (p < 0.001) after subtrochanteric and supracondylar osteotomy, respectively. PDFA changed a mean of 1° (− 2.3 to 1.3) (p < 0.01) and 0.5° (− 1.9 to 0.3) (p < 0.01), respectively. The amount of femAT correction was associated with increased postoperative deviation of the mechanical leg axis (p < 0.01). Using multiple regression analysis, no other morphological factors were found to inluence mLDFA or PDFA. Internal rotational osteotomies decreased the ischial-lesser trochanteric space by < 5 mm in both the frontal and sagittal plane (p < 0.001). Conclusions In case of femAT correction of ≤ 20°, neither subtrochanteric nor supracondylar femoral derotational or rotational osteotomies have a clinically relevant impact on frontal or sagittal leg alignment. A relevant deviation in the sagittal (but not frontal plane) might occur in case of a > 25° subtrochanteric femAT correction. Level of evidence IV.

Excessive femoral torsion is not associated with patellofemoral pain or instability if TKA is functionally aligned and the patella denervated

“…Previous reports advocated for restoration of individual patellofemoral tracking with the aim of decreasing the risk of anterior knee pain [14,15]. As the role of excessive FT in TKA has not yet been explored in literature, the main goal of this prospective study was to answer the question whether excessive FT should be corrected in TKA, as it is increasingly performed in patients with patellofemoral instability [4,7,9,11,18,19]. However, no correlation between FT and scores which are specific for the patellofemoral complaints could be found.…”

“…malalignment have recently become popular [4,7,9,11]. Furthermore, femoral rotational deformity was elaborated to affect patellar tracking and increase joint stress, resulting in accelerated femoropatellar joint degeneration [8,26].…”

The Relationship between Frontal, Axial Leg Alignment, and Ankle Joint Line Orientation—a Radiographic Analysis of Healthy Subjects

“…Unintentional created obliquity of the AJLO after a corrective osteotomy could potentially deteriorate a pre‐existing ankle disorder. Patients scheduled for torsional realignment >20° are especially at risk for coronal malalignment 26 and should be screened for concomitant ankle pathologies. Furthermore, the extent of the planned surgical correction should be evaluated individually based on the patient's symptoms and adjacent joint disorders.…”

A novel patient-specific 3D printed guide for accurate femoral derotation osteotomies: a case report

“…The most common malalignment after femoral IM nailing is internal rotation of the distal part resulting in increased femoral anteversion or femoral anteversion angle (FAVA) (normal value 15°±10°) ( 4 , 5 ). Relevant mechanical leg axis deviation might be expected in case of >20° side to side difference ( 6 ). However, increased femoral anteversion results in an elevated patellofemoral contract pressure, toeing-in during gait and anterior groin pain ( 1 , 3 , 7 , 8 ).…”