Average baseline utility, QALY,* revision rate and length of time to revision
| Measure | THA | TKA | Decompression for FLSS | Decompression with fusion for FLSS |
|---|---|---|---|---|
| Baseline utility, mean (SD) | 0.522 (0.222) | 0.549 (0.0831) | 0.563 (0.271) | 0.564 (0.233) |
| 2-year utility, mean (SD) | 0.715 (0.315) | 0.642 (0.148) | 0.687 (0.324) | 0.721 (0.301) |
| 2-year utility gain over baseline, mean (SD)† | 0.193 (0.157) | 0.093 (0.150) | 0.124 (0.128) | 0.156 (0.140) |
| 2-year QALY gain over baseline | 0.275 | 0.132 | 0.177 | 0.223 |
| Lifetime QALY gain over baseline | 2.778 | 1.273 | 1.721 | 2.173 |
| Average LOS of primary surgery, d | 7.28 | 7.02 | 5.46 | 8.83 |
| Revision rate at 2 years, % | 1.05 | 8.33 | 21.4 | 16.67 |
| Average length of time to revision, mo | 9.00 | 7.38 | 5.75 | 15.00 |
FLSS = focal lumbar spinal stenosis; LOS = length of stay; QALY = quality adjusted life years; SD = standard deviation; THA = total hip arthroplasty; TKA = total knee arthroplasty.
↵* QALY gains discounted using a 3% annualized rate.
↵† There was a significant utility gain over baseline at 2 years for THA (p < 0.01, t test), TKA (p < 0.01, t test) and surgery for FLSS (p < 0.01, t test).