Table 2.
Model parameters used in the decision tree
| Probabilities, utilities & disutilities | Absolute mean probability | Utility or disutility | Range of individual studies |
|---|---|---|---|
| Resurfaced patellae | |||
| Probability of AKP | 0.120 | 0.021–0.467 | |
| Probability of NO AKP | 0.880 | 0.533–0.970 | |
| Probability of AKP + Implant failure | 0.067 | 0–0.200 | |
| Probability of AKP + NO Implant failure | 0.933 | 0.800–1 | |
| Probability of AKP + Implant failure + Revision + NO Pain | 0.250 | 0–1 | |
| Probability of AKP + Implant failure + Revision + Pain | 0.750 | 0–1 | |
| Probability of AKP + NO Implant failure + Revision + NO Pain | 0.700 | 0–1 | |
| Probability of AKP + NO Implant failure + Revision + Pain | 0.300 | 0–1 | |
| Nonresurfaced patellae | |||
| Probability of AKP | 0.257 | 0.077–0.429 | |
| Probability of NO AKP | 0.743 | 0.571–0.923 | |
| Probability of AKP + Secondary resurfacing + NO Pain | 0.395 | 0.067–0.909 | |
| Probability of AKP + Secondary resurfacing + Pain | 0.605 | 0.091–0.933 | |
| Utilities and disutilities | |||
| Preoperative utility [3] | 0.52 | ||
| Expected postop utility, without pain, excluding disutility [3] | 0.79 | ||
| Expected postop utility, with AKP, excluding disutility | 0.62 | ||
| Disutility for total knee arthroplasty | 0.10 | ||
| Disutility for revision surgery after TKA | 0.10 | ||
| Disutility of implant failure | 0.02 | ||
| Calculated utilities | |||
| Pain-free after one operation | 0.69 | ||
| Pain-free after two operations | 0.59 | ||
| Persistent pain after one operation | 0.52 | ||
| Persistent pain after two operations | 0.42 | ||