The impact of surgical reduction of high-grade lumbosacral spondylolisthesis on proximal femoral angle and quality of life

Abstract

BACKGOUND CONTEXTAbnormal proximal femoral angle (PFA) was recently found to be associated with deteriorating sagittal balance and quality of life (QoL) in high-grade spondylolisthesis (HGS). However, the influence of PFA on the QoL of patients undergoing surgery remains unknown. PURPOSEThis study compares the pre- and postoperative measurements of sagittal balance including PFA in patients with lumbosacral HGS after surgery. It also determines if PFA is a radiographic parameter that is associated with QoL in patients undergoing surgery. STUDY DESIGNRetrospective cohort study. PATIENT SAMPLEThirty-three patients (mean age 15.6 ± 3.0 years) operated for L5-S1 HGS between July 2002 and April 2015. Thirteen had in situ fusion and 20 had reduction to a low-grade slip. OUTCOME MEASURESThe outcome measures included PFA and QoL scores measured from the Scoliosis Research Society SRS-30 QoL questionnaire. METHODSThe minimum follow-up was 2 years. PFA and QoL were compared pre- and postoperatively. Statistical analysis used nonparametric Mann-Whitney and Wilcoxon Signed Rank tests, Chi-square tests to compare proportions, and bivariate correlations with Spearman's coefficients. RESULTSA decreasing PFA correlated with less pain (r = −0.56, p = .010), improved function (r = −0.51, p = .022) and better self-image (r = −0.46, p = .044) postreduction. Reduction decreased PFA by 5.1° (p = .002), whereas in situ fusion did not alter PFA significantly. Patients with normal preoperative PFA had similar postoperative QoL regardless of the type of surgery, except for self-image, which improved further with reduction (3.73 ± 0.49 to 4.26 ± 0.58, p = .015). Patients with abnormal preoperative PFA tended to have a higher QoL in all domains after reduction. CONCLUSIONDecreasing PFA correlates with less pain, better function and self-image. Reduction of HGS decreases PFA. Reduction also relates to a better postoperative QoL when the preoperative PFA is abnormal. When the preoperative PFA is normal, in situ fusion is equivalent to reduction except for self-image, which is better improved after reduction.