| M23 | Internal derangement of knee | NON-BILLABLE CODE |
| M23.0 | Cystic meniscus | NON-BILLABLE CODE |
| M23.00 | Cystic meniscus, unspecified meniscus | NON-BILLABLE CODE |
| M23.000 | Cystic meniscus, unspecified lateral meniscus, right knee | BILLABLE CODE |
| M23.001 | Cystic meniscus, unspecified lateral meniscus, left knee | BILLABLE CODE |
| M23.002 | Cystic meniscus, unspecified lateral meniscus, unspecified knee | BILLABLE CODE |
| M23.003 | Cystic meniscus, unspecified medial meniscus, right knee | BILLABLE CODE |
| M23.004 | Cystic meniscus, unspecified medial meniscus, left knee | BILLABLE CODE |
| M23.005 | Cystic meniscus, unspecified medial meniscus, unspecified knee | BILLABLE CODE |
| M23.006 | Cystic meniscus, unspecified meniscus, right knee | BILLABLE CODE |
| M23.007 | Cystic meniscus, unspecified meniscus, left knee | BILLABLE CODE |
| M23.009 | Cystic meniscus, unspecified meniscus, unspecified knee | BILLABLE CODE |
| M23.01 | Cystic meniscus, anterior horn of medial meniscus | NON-BILLABLE CODE |
| M23.011 | Cystic meniscus, anterior horn of medial meniscus, right knee | BILLABLE CODE |
| M23.012 | Cystic meniscus, anterior horn of medial meniscus, left knee | BILLABLE CODE |
| M23.019 | Cystic meniscus, anterior horn of medial meniscus, unspecified knee | BILLABLE CODE |
| M23.02 | Cystic meniscus, posterior horn of medial meniscus | NON-BILLABLE CODE |
| M23.021 | Cystic meniscus, posterior horn of medial meniscus, right knee | BILLABLE CODE |
| M23.022 | Cystic meniscus, posterior horn of medial meniscus, left knee | BILLABLE CODE |
| M23.029 | Cystic meniscus, posterior horn of medial meniscus, unspecified knee | BILLABLE CODE |
| M23.03 | Cystic meniscus, other medial meniscus | NON-BILLABLE CODE |
| M23.031 | Cystic meniscus, other medial meniscus, right knee | BILLABLE CODE |
| M23.032 | Cystic meniscus, other medial meniscus, left knee | BILLABLE CODE |
| M23.039 | Cystic meniscus, other medial meniscus, unspecified knee | BILLABLE CODE |
| M23.04 | Cystic meniscus, anterior horn of lateral meniscus | NON-BILLABLE CODE |
| M23.041 | Cystic meniscus, anterior horn of lateral meniscus, right knee | BILLABLE CODE |
| M23.042 | Cystic meniscus, anterior horn of lateral meniscus, left knee | BILLABLE CODE |
| M23.049 | Cystic meniscus, anterior horn of lateral meniscus, unspecified knee | BILLABLE CODE |
| M23.05 | Cystic meniscus, posterior horn of lateral meniscus | NON-BILLABLE CODE |
| M23.052 | Cystic meniscus, posterior horn of lateral meniscus, left knee | BILLABLE CODE |
| M23.059 | Cystic meniscus, posterior horn of lateral meniscus, unspecified knee | BILLABLE CODE |
| M23.06 | Cystic meniscus, other lateral meniscus | NON-BILLABLE CODE |
| M23.061 | Cystic meniscus, other lateral meniscus, right knee | BILLABLE CODE |
| M23.062 | Cystic meniscus, other lateral meniscus, left knee | BILLABLE CODE |
| M23.069 | Cystic meniscus, other lateral meniscus, unspecified knee | BILLABLE CODE |
| M23.2 | Derangement of meniscus due to old tear or injury | NON-BILLABLE CODE |
| M23.20 | Derangement of unspecified meniscus due to old tear or injury | NON-BILLABLE CODE |
| M23.200 | Derangement of unspecified lateral meniscus due to old tear or injury, right knee | BILLABLE CODE |
| M23.201 | Derangement of unspecified lateral meniscus due to old tear or injury, left knee | BILLABLE CODE |
| M23.202 | Derangement of unspecified lateral meniscus due to old tear or injury, unspecified knee | BILLABLE CODE |
| M23.203 | Derangement of unspecified medial meniscus due to old tear or injury, right knee | BILLABLE CODE |
| M23.204 | Derangement of unspecified medial meniscus due to old tear or injury, left knee | BILLABLE CODE |
| M23.205 | Derangement of unspecified medial meniscus due to old tear or injury, unspecified knee | BILLABLE CODE |
| M23.206 | Derangement of unspecified meniscus due to old tear or injury, right knee | BILLABLE CODE |
| M23.207 | Derangement of unspecified meniscus due to old tear or injury, left knee | BILLABLE CODE |
| M23.209 | Derangement of unspecified meniscus due to old tear or injury, unspecified knee | BILLABLE CODE |
| M23.21 | Derangement of anterior horn of medial meniscus due to old tear or injury | NON-BILLABLE CODE |
| M23.211 | Derangement of anterior horn of medial meniscus due to old tear or injury, right knee | BILLABLE CODE |
| M23.212 | Derangement of anterior horn of medial meniscus due to old tear or injury, left knee | BILLABLE CODE |
| M23.219 | Derangement of anterior horn of medial meniscus due to old tear or injury, unspecified knee | BILLABLE CODE |
| M23.22 | Derangement of posterior horn of medial meniscus due to old tear or injury | NON-BILLABLE CODE |
| M23.221 | Derangement of posterior horn of medial meniscus due to old tear or injury, right knee | BILLABLE CODE |
| M23.222 | Derangement of posterior horn of medial meniscus due to old tear or injury, left knee | BILLABLE CODE |
| M23.229 | Derangement of posterior horn of medial meniscus due to old tear or injury, unspecified knee | BILLABLE CODE |
| M23.23 | Derangement of other medial meniscus due to old tear or injury | NON-BILLABLE CODE |
| M23.231 | Derangement of other medial meniscus due to old tear or injury, right knee | BILLABLE CODE |
| M23.232 | Derangement of other medial meniscus due to old tear or injury, left knee | BILLABLE CODE |
| M23.239 | Derangement of other medial meniscus due to old tear or injury, unspecified knee | BILLABLE CODE |
| M23.24 | Derangement of anterior horn of lateral meniscus due to old tear or injury | NON-BILLABLE CODE |
| M23.241 | Derangement of anterior horn of lateral meniscus due to old tear or injury, right knee | BILLABLE CODE |
| M23.242 | Derangement of anterior horn of lateral meniscus due to old tear or injury, left knee | BILLABLE CODE |
| M23.249 | Derangement of anterior horn of lateral meniscus due to old tear or injury, unspecified knee | BILLABLE CODE |
| M23.25 | Derangement of posterior horn of lateral meniscus due to old tear or injury | NON-BILLABLE CODE |
| M23.251 | Derangement of posterior horn of lateral meniscus due to old tear or injury, right knee | BILLABLE CODE |
| M23.252 | Derangement of posterior horn of lateral meniscus due to old tear or injury, left knee | BILLABLE CODE |
| M23.259 | Derangement of posterior horn of lateral meniscus due to old tear or injury, unspecified knee | BILLABLE CODE |
| M23.26 | Derangement of other lateral meniscus due to old tear or injury | NON-BILLABLE CODE |
| M23.261 | Derangement of other lateral meniscus due to old tear or injury, right knee | BILLABLE CODE |
| M23.262 | Derangement of other lateral meniscus due to old tear or injury, left knee | BILLABLE CODE |
| M23.269 | Derangement of other lateral meniscus due to old tear or injury, unspecified knee | BILLABLE CODE |
| M23.3 | Other meniscus derangements | NON-BILLABLE CODE |
| M23.30 | Other meniscus derangements, unspecified meniscus | NON-BILLABLE CODE |
| M23.300 | Other meniscus derangements, unspecified lateral meniscus, right knee | BILLABLE CODE |
| M23.301 | Other meniscus derangements, unspecified lateral meniscus, left knee | BILLABLE CODE |
| M23.302 | Other meniscus derangements, unspecified lateral meniscus, unspecified knee | BILLABLE CODE |
| M23.303 | Other meniscus derangements, unspecified medial meniscus, right knee | BILLABLE CODE |
| M23.304 | Other meniscus derangements, unspecified medial meniscus, left knee | BILLABLE CODE |
| M23.305 | Other meniscus derangements, unspecified medial meniscus, unspecified knee | BILLABLE CODE |
| M23.306 | Other meniscus derangements, unspecified meniscus, right knee | BILLABLE CODE |
| M23.307 | Other meniscus derangements, unspecified meniscus, left knee | BILLABLE CODE |
| M23.309 | Other meniscus derangements, unspecified meniscus, unspecified knee | BILLABLE CODE |
| M23.31 | Other meniscus derangements, anterior horn of medial meniscus | NON-BILLABLE CODE |
| M23.311 | Other meniscus derangements, anterior horn of medial meniscus, right knee | BILLABLE CODE |
| M23.312 | Other meniscus derangements, anterior horn of medial meniscus, left knee | BILLABLE CODE |
| M23.319 | Other meniscus derangements, anterior horn of medial meniscus, unspecified knee | BILLABLE CODE |
| M23.32 | Other meniscus derangements, posterior horn of medial meniscus | NON-BILLABLE CODE |
| M23.321 | Other meniscus derangements, posterior horn of medial meniscus, right knee | BILLABLE CODE |
| M23.322 | Other meniscus derangements, posterior horn of medial meniscus, left knee | BILLABLE CODE |
| M23.329 | Other meniscus derangements, posterior horn of medial meniscus, unspecified knee | BILLABLE CODE |
| M23.33 | Other meniscus derangements, other medial meniscus | NON-BILLABLE CODE |
| M23.331 | Other meniscus derangements, other medial meniscus, right knee | BILLABLE CODE |
| M23.332 | Other meniscus derangements, other medial meniscus, left knee | BILLABLE CODE |
| M23.339 | Other meniscus derangements, other medial meniscus, unspecified knee | BILLABLE CODE |
| M23.34 | Other meniscus derangements, anterior horn of lateral meniscus | NON-BILLABLE CODE |
| M23.341 | Other meniscus derangements, anterior horn of lateral meniscus, right knee | BILLABLE CODE |
| M23.342 | Other meniscus derangements, anterior horn of lateral meniscus, left knee | BILLABLE CODE |
| M23.349 | Other meniscus derangements, anterior horn of lateral meniscus, unspecified knee | BILLABLE CODE |
| M23.35 | Other meniscus derangements, posterior horn of lateral meniscus | NON-BILLABLE CODE |
| M23.351 | Other meniscus derangements, posterior horn of lateral meniscus, right knee | BILLABLE CODE |
| M23.352 | Other meniscus derangements, posterior horn of lateral meniscus, left knee | BILLABLE CODE |
| M23.359 | Other meniscus derangements, posterior horn of lateral meniscus, unspecified knee | BILLABLE CODE |
| M23.36 | Other meniscus derangements, other lateral meniscus | NON-BILLABLE CODE |
| M23.361 | Other meniscus derangements, other lateral meniscus, right knee | BILLABLE CODE |
| M23.362 | Other meniscus derangements, other lateral meniscus, left knee | BILLABLE CODE |
| M23.369 | Other meniscus derangements, other lateral meniscus, unspecified knee | BILLABLE CODE |
| M23.4 | Loose body in knee | NON-BILLABLE CODE |
| M23.40 | Loose body in knee, unspecified knee | BILLABLE CODE |
| M23.41 | Loose body in knee, right knee | BILLABLE CODE |
| M23.42 | Loose body in knee, left knee | BILLABLE CODE |
| M23.5 | Chronic instability of knee | NON-BILLABLE CODE |
| M23.50 | Chronic instability of knee, unspecified knee | BILLABLE CODE |
| M23.51 | Chronic instability of knee, right knee | BILLABLE CODE |
| M23.52 | Chronic instability of knee, left knee | BILLABLE CODE |
| M23.6 | Other spontaneous disruption of ligament(s) of knee | NON-BILLABLE CODE |
| M23.60 | Other spontaneous disruption of unspecified ligament of knee | NON-BILLABLE CODE |
| M23.601 | Other spontaneous disruption of unspecified ligament of right knee | BILLABLE CODE |
| M23.602 | Other spontaneous disruption of unspecified ligament of left knee | BILLABLE CODE |
| M23.609 | Other spontaneous disruption of unspecified ligament of unspecified knee | BILLABLE CODE |
| M23.61 | Other spontaneous disruption of anterior cruciate ligament of knee | NON-BILLABLE CODE |
| M23.611 | Other spontaneous disruption of anterior cruciate ligament of right knee | BILLABLE CODE |
| M23.612 | Other spontaneous disruption of anterior cruciate ligament of left knee | BILLABLE CODE |
| M23.619 | Other spontaneous disruption of anterior cruciate ligament of unspecified knee | BILLABLE CODE |
| M23.62 | Other spontaneous disruption of posterior cruciate ligament of knee | NON-BILLABLE CODE |
| M23.621 | Other spontaneous disruption of posterior cruciate ligament of right knee | BILLABLE CODE |
| M23.622 | Other spontaneous disruption of posterior cruciate ligament of left knee | BILLABLE CODE |
| M23.629 | Other spontaneous disruption of posterior cruciate ligament of unspecified knee | BILLABLE CODE |
| M23.63 | Other spontaneous disruption of medial collateral ligament of knee | NON-BILLABLE CODE |
| M23.631 | Other spontaneous disruption of medial collateral ligament of right knee | BILLABLE CODE |
| M23.632 | Other spontaneous disruption of medial collateral ligament of left knee | BILLABLE CODE |
| M23.639 | Other spontaneous disruption of medial collateral ligament of unspecified knee | BILLABLE CODE |
| M23.64 | Other spontaneous disruption of lateral collateral ligament of knee | NON-BILLABLE CODE |
| M23.641 | Other spontaneous disruption of lateral collateral ligament of right knee | BILLABLE CODE |
| M23.642 | Other spontaneous disruption of lateral collateral ligament of left knee | BILLABLE CODE |
| M23.649 | Other spontaneous disruption of lateral collateral ligament of unspecified knee | BILLABLE CODE |
| M23.67 | Other spontaneous disruption of capsular ligament of knee | NON-BILLABLE CODE |
| M23.671 | Other spontaneous disruption of capsular ligament of right knee | BILLABLE CODE |
| M23.672 | Other spontaneous disruption of capsular ligament of left knee | BILLABLE CODE |
| M23.679 | Other spontaneous disruption of capsular ligament of unspecified knee | BILLABLE CODE |
| M23.8 | Other internal derangements of knee | NON-BILLABLE CODE |
| M23.8X | Other internal derangements of knee | NON-BILLABLE CODE |
| M23.8X1 | Other internal derangements of right knee | BILLABLE CODE |
| M23.8X2 | Other internal derangements of left knee | BILLABLE CODE |
| M23.8X9 | Other internal derangements of unspecified knee | BILLABLE CODE |
| M23.9 | Unspecified internal derangement of knee | NON-BILLABLE CODE |
| M23.90 | Unspecified internal derangement of unspecified knee | BILLABLE CODE |
| M23.91 | Unspecified internal derangement of right knee | BILLABLE CODE |
| M23.92 | Unspecified internal derangement of left knee | BILLABLE CODE |
