Table 2.
Diagnostic utility of self-reported pain in identifying PFJ damage (comparing knees with isolated PFJ full-thickness cartilage damage or BML to knees with either isolated TJF or no full-thickness cartilage damage or BML).
| Prevalence | Sensitivity | Specificity | LR+ | PPV | NPV | ||
|---|---|---|---|---|---|---|---|
| AKP | Any | 53 | 60 | 53 | 1.3 | 53 | 59 |
| Isolated | 23 | 27 | 81 | 1.4 | 57 | 55 | |
| Max pain with stairs (up or down) | (≥ min) | 70 | 74 | 33 | 1.1 | 50 | 58 |
| (≥ mod) | 35 | 40 | 70 | 1.3 | 54 | 56 | |
| Pain going up stairs | (≥ min) | 69 | 72 | 34 | 1.1 | 49 | 57 |
| (≥ mod) | 30 | 35 | 74 | 1.3 | 54 | 56 | |
| Pain going down stairs | (≥ min) | 62 | 64 | 40 | 1.1 | 49 | 55 |
| (≥ mod) | 25 | 32 | 80 | 1.6 | 59 | 57 | |
| Absence of pain walking on level ground | (≥ min) | 57 | 58 | 44 | 1.0 | 48 | 54 |
| (≥ mod) | 90 | 93 | 13 | 1.1 | 49 | 68 | |
| Any AKP + max pain with stairs | (≥ min) | 42 | 49 | 64 | 1.4 | 56 | 58 |
| (≥ mod) | 23 | 29 | 82 | 1.6 | 60 | 56 | |
| Any AKP + absence of pain walking on level ground | (≥ min) | 27 | 30 | 76 | 1.3 | 52 | 54 |
| (≥ mod) | 47 | 56 | 60 | 1.4 | 56 | 60 | |
| Isolated AKP + max pain with stairs | (≥ min) | 15 | 20 | 90 | 2.0 | 63 | 55 |
| (≥ mod) | 6 | 9 | 97 | 3.0 | 72 | 54 | |
| Isolated AKP + absence of pain walking on level ground | (≥ min) | 16 | 20 | 86 | 1.4 | 57 | 54 |
| (≥ mod) | 22 | 26 | 82 | 1.4 | 57 | 55 |
LR+: positive likelihood ratio (Sn/1-Sp); PPV: positive predictive value; NPV: negative predictive value; AKP: anterior knee pain; max: maximum; min: minimal; mod: moderate; PFJ: patellofemoral joint; TFJ: tibiofemoral joint; BML: bone marrow lesions.