Radiological Parameter Radiological Parameter Description
C7-Sagittal vertical axis (C7-SVA) Horizontal distance between a line from the center of the C7 vertebral body to the posterior superior corner of the sacral endplate and a plumb line from the center of the C7 vertebral body. Assuming >50mm as imbalanced
Pelvic incidence-lumbar lordosis mismatch (PI-LL mismatch)
Difference between pelvic incidence and lumbar lordosis assuming
>10° difference as imbalanced
Cervical lordosis (CL) Angle between inferior endplate of C2 and inferior endplate of C7 Thoracic kyphosis (TK) Angle between superior endplate of T4 and inferior endplate T12 Lumbar lordosis (LL) Angle between superior endplate of L1 and superior endplate of S1 C7- central sacral vertical line (C7-
CSVL)
Horizontal distance between a vertical line drawn from the midpoint of the C7 vertebral body and the midline of the sacrum. Plumb line passes more than 2 cm to the right/ left of the midline (positive/ negative balance), in between ±2cm neutral balance
Pelvic oblique angle-lumbosacral (POA-ls)
Angle between a line drawn through the spinous process of L4 and L5 and a perpendicular though the iliac crest line (EOS sitting)
Intra pelvic oblique angle (Intra- PO)
Defined as mean between angle 1 and 2. Angle 1 defined between iliac crest line and line along the bottom of the fourth lumbar vertebra.
Angle 2 between the aforementioned line along the bottom of the fourth lumbar vertebra and a line connecting the bottom of the ischia ramus
Pelvic incidence (PI) Angle between the line connecting the midpoint of the superior plate of S1 and the midpoint of the hip axis with the line perpendicular to the superior plate of S1
Pelvic radius-S1 angle (PR-S1A) Angle between the line from the midpoint of the hip axis to the superior posterior corner of S1 and the superior sacral endplate.
Sacral slope (SS) Angle between the superior endplate of S1 and a horizontal line Pelvic tilt (PT) Angle between the line joining the midpoint of the hip axis to the
midpoint of S1superior endplate and the vertical reference line Anterior plane pelvic tilt (APPT) Angle between the line connecting the midpoint of both anterior
superior iliac spines to the pubic symphysis, and a vertical line
Pelvic femoral angle (PFA) Angle between the center of the hip axis to the midpoint of the superior sacral endplate and a 10 cm line from the center of the hip axis to the ventral cortex of the femur
Supplement Table 1. Measured radiological parameters with description arranged by global sagittal spinal alignment, sagittal and coronal spinal parameter, and spinopelvic parameter.
Interrater Reliability
Preoperative Postoperative Mean (Pre- postoperative)
C7-Sagittal vertical axis .614 .571 .593
Cervical lordosis .662 .691 .677
Thoracic kyphosis .652 .638 .645
Lumbar lordosis .746 .779 .763
C7- central sacral vertical line .614 .555 .585
Pelvic oblique angle-lumbosacral .550 .671 .611
Intra pelvic oblique angle .645 .739 .692
Pelvic incidence .534 .728 .631
Pelvic radius-S1 angle .578 .720 .649
Sacral slope .533 .711 .622
Pelvic tilt .900 .816 .858
Anterior plane pelvic tilt .520 .554 .537
Pelvic femoral angle .694 .831 .763
Supplement Table 2. Pre-and postoperative values and the mean of interrater reliability of the global spinal alignment, spinal sagittal and coronal and spinopelvic parameter. Spearman´s rank correlation coefficient was used.
Classification of hip osteoarthritis on the contralateral hip Kellgren & Lawrence
classification
Quantity N Proportion (%)
Grade 0 0/153 0
Grade 1 2/153 1.3
Grade 2 105/153 68.6
Grade 3 29/153 19.0
Grade 4 17/153 11.1
Supplement Table 3. Classification of hip osteoarthritis on the contralateral hip according to Kellgren & Lawrence classification of osteoarthritis depicting quantity (N) and proportion (%) from all 153 analyzed patients.
Intrarater Reliability
Preoperative Postoperative Mean (Pre- postoperative)
C7-Sagittal vertical axis .965 .986 .976
Cervical lordosis .954 .944 .949
Thoracic kyphosis .967 .953 .960
Lumbar lordosis .957 .872 .915
C7- central sacral vertical line .879 .928 .904
Pelvic oblique angle-lumbosacral .726 .731 .729
Intra pelvic oblique angle .536 . 838 .687
Pelvic incidence .853 .961 .907
Pelvic radius-S1 angle .865 .945 .905
Sacral slope .862 .968 .915
Pelvic tilt .969 .950 .960
Anterior plane pelvic tilt .742 .761 .752
Pelvic femoral angle .914 .966 .940
Supplement Table 4. Pre-and postoperative values and the mean of intrarater reliability of the global spinal alignment, spinal sagittal and coronal and spinopelvic parameter. Spearman’s rank correlation coefficient was used.
S upplement Figure 1. Sagittal standing EOS Radiographs preoperative (A) and postoperative (B)
demonstrating the decreasing posterior pelvic tilt postoperatively with decreasing PT (Pre/Post:
21.8°/15.9°) and APPT (Pre/Post: -8.3°/-6.6°) and accordingly increasing SS (Pre/Post: 33.9°/38.5°).
