Measure | All patients^{*} | Patients with DLS who underwent decompression alone, and the matched patients with hip or knee OA^{†} | Patients with DLS who underwent decompression with fusion, and the matched patients with hip or knee OA^{‡} | ||||||
---|---|---|---|---|---|---|---|---|---|

MIS decompression with or without fusion for DLSn = 66 | Primary THA for hip OAn = 66 | Primary TKA for knee OAn = 66 | MIS decompression for DLSn = 35 | Primary THA for hip OAn = 35 | Primary TKA for knee OAn = 35 | MIS decompression and fusion for DLSn = 31 | Primary THA for hip OAn = 31 | Primary TKA for knee OAn = 31 | |

Baseline utility, mean ± SD | 0.578 ± 0.089 | 0.636 ± 0.116 | 0.657 ± 0.131 | 0.592 ± 0.079 | 0.640 ± 0.132 | 0.592 ± 0.079 | 0.562 ± 0.097 | 0.632 ± 0.096 | 0.664 ± 0.129 |

Follow-up utility, mean ± SD | 0.705 ± 0.120 | 0.797 ± 0.142 | 0.770 ± 0.143 | 0.710 ± 0.126 | 0.789 ± 0.151 | 0.752 ± 0.141 | 0.699 ± 0.116 | 0.807 ± 0.132 | 0.791 ± 0.145 |

Utility change, mean ± SD | 0.127 ± 0.134 | 0.161 ± 0.143 | 0.113 ± 0.132 | 0.118 ± 0.136 | 0.149 ± 0.157 | 0.101 ± 0.127 | 0.137 ± 0.134 | 0.175 ± 0.128 | 0.127 ± 0.138 |

Lifetime QALY gain, mean ± SD^{§} | 1.948 ± 2.106 | 2.470 ± 2.298 | 1.784 ± 2.139 | 1.658 ± 1.842 | 2.102 ± 2.293 | 1.468 ± 1.987 | 2.276 ± 2.356 | 2.887 ± 2.268 | 2.142 ± 2.278 |

Note: ANOVA = analysis of variance; DLS = degenerative lumbar spondylolisthesis; MD = mean difference; MIS = minimally invasive surgery; OA = ostearthritis; QALY = quality-adjusted life year; SD = standard deviation; THA = total hip arthroplasty; TKA = total knee arthroplasty.

↵* Baseline utility was significantly lower (

*p*< 0.003, ANOVA) for the DLS group than for the H-OA group (MD 0.058,*p*= 0.011) or the K-OA group (MD 0.079,*p*< 0.001). Follow-up utility was significantly lower (*p*< 0.004, ANOVA) for the DLS group than for the H-OA group (MD 0.093,*p*<0.001) or the K-OA group (MD 0.065,*p*= 0.018). There was no significant difference (*p*= 0.12, ANOVA) in utility gains between the groups. There was a significant utility gain at follow-up from baseline values for the DLS group (*p*< 0.001, paired*t*test), the H-OA group (*p*< 0.001, paired*t*test) and the K-OA group (*p*< 0.001, paired*t*test).↵† There was no significant difference (

*p*= 0.09, ANOVA) in baseline utility between the groups. There was no significant difference (*p*= 0.07, ANOVA) in follow-up utility between the groups. There was no significant difference (*p*= 0.36, ANOVA) in utility gains between the groups. There was a significant utility gain at follow-up from baseline values for the DLS group (*p*< 0.001, paired*t*test), the H-OA group (*p*< 0.001, paired*t*test) and the K-OA group (*p*< 0.001, paired*t*test).↵‡ Baseline utility was significantly lower (

*p*= 0.001, ANOVA) for the DLS group than for the H-OA group (MD 0.07,*p*= 0.039) or the K-OA group (MD 0.102,*p*= 0.001). Follow-up utility was significantly lower (*p*= 0.001, ANOVA) for the DLS group than for the H-OA group (MD 0.108;*p*= 0.005) or the K-OA group (MD 0.092;*p*= 0.022). There was no significant difference (*p*= 0.33, ANOVA) in utility gains between the groups. There was a significant utility gain at follow-up from baseline values for the DLS group (*p*< 0.001, paired*t*test), the H-OA group (*p*< 0.001, paired*t*test) and the K-OA group (*p*< 0.001, paired*t*test).↵§ QALY gains were discounted at a 3% annualized rate.