| S81.001 | Unspecified open wound, right knee | NON-BILLABLE CODE |
| S81.001A | Unspecified open wound, right knee, initial encounter | BILLABLE CODE |
| S81.001D | Unspecified open wound, right knee, subsequent encounter | BILLABLE CODE |
| S81.001S | Unspecified open wound, right knee, sequela | BILLABLE CODE |
| S81.002 | Unspecified open wound, left knee | NON-BILLABLE CODE |
| S81.002A | Unspecified open wound, left knee, initial encounter | BILLABLE CODE |
| S81.002D | Unspecified open wound, left knee, subsequent encounter | BILLABLE CODE |
| S81.002S | Unspecified open wound, left knee, sequela | BILLABLE CODE |
| S81.009 | Unspecified open wound, unspecified knee | NON-BILLABLE CODE |
| S81.009A | Unspecified open wound, unspecified knee, initial encounter | BILLABLE CODE |
| S81.009D | Unspecified open wound, unspecified knee, subsequent encounter | BILLABLE CODE |
| S81.009S | Unspecified open wound, unspecified knee, sequela | BILLABLE CODE |
