DxCodebookFY2027 · Oct 1, 2026 – Sep 30, 2027

Category · FY2027

M21 Other acquired deformities of limbs

  • Header · not billable

M21 is not billable. The category heads 124 billable codes in FY2027, grouped under 10 subdivisions.

Index → code

Where it sits

  1. Chapter 13 Diseases of the musculoskeletal system and connective tissue (M00-M99)
  2. M20-M25 Other joint disorders (M20-M25)
  3. M21 Other acquired deformities of limbs
Billable codes
124
Subdivisions
10
CC / MCC codes
0 / 0
HCC V28 codes
0
New FY2027
0
Index entries
64

Codes in M21

  1. M21.0
    Valgus deformity, not elsewhere classified
    Header
    Excludes1 2

    Excludes1

    • metatarsus valgus (Q66.6) Q66.6
    • talipes calcaneovalgus (Q66.4-) Q66.4
  2. M21.00
    Valgus deformity, not elsewhere classified, unspecified site
    Billable
  3. M21.02
    Valgus deformity, not elsewhere classified, elbow
    Header
    Inclusion terms 1

    Inclusion terms

    • Cubitus valgus
  4. M21.021
    Valgus deformity, not elsewhere classified, right elbow
    Billable
  5. M21.022
    Valgus deformity, not elsewhere classified, left elbow
    Billable
  6. M21.029
    Valgus deformity, not elsewhere classified, unspecified elbow
    Billable
  7. M21.05
    Valgus deformity, not elsewhere classified, hip
    Header
  8. M21.051
    Valgus deformity, not elsewhere classified, right hip
    Billable
  9. M21.052
    Valgus deformity, not elsewhere classified, left hip
    Billable
  10. M21.059
    Valgus deformity, not elsewhere classified, unspecified hip
    Billable
  11. M21.06
    Valgus deformity, not elsewhere classified, knee
    Header
    Inclusion terms 2

    Inclusion terms

    • Genu valgum
    • Knock knee
  12. M21.061
    Valgus deformity, not elsewhere classified, right knee
    Billable
  13. M21.062
    Valgus deformity, not elsewhere classified, left knee
    Billable
  14. M21.069
    Valgus deformity, not elsewhere classified, unspecified knee
    Billable
  15. M21.07
    Valgus deformity, not elsewhere classified, ankle
    Header
  16. M21.071
    Valgus deformity, not elsewhere classified, right ankle
    Billable
  17. M21.072
    Valgus deformity, not elsewhere classified, left ankle
    Billable
  18. M21.079
    Valgus deformity, not elsewhere classified, unspecified ankle
    Billable
  19. M21.1
    Varus deformity, not elsewhere classified
    Header
    Excludes1 2

    Excludes1

    • metatarsus varus (Q66.22-) Q66.22
    • tibia vara (M92.51-) M92.51
  20. M21.10
    Varus deformity, not elsewhere classified, unspecified site
    Billable
  21. M21.12
    Varus deformity, not elsewhere classified, elbow
    Header
    Inclusion terms 1

    Inclusion terms

    • Cubitus varus, elbow
  22. M21.121
    Varus deformity, not elsewhere classified, right elbow
    Billable
  23. M21.122
    Varus deformity, not elsewhere classified, left elbow
    Billable
  24. M21.129
    Varus deformity, not elsewhere classified, unspecified elbow
    Billable
  25. M21.15
    Varus deformity, not elsewhere classified, hip
    Header
  26. M21.151
    Varus deformity, not elsewhere classified, right hip
    Billable
  27. M21.152
    Varus deformity, not elsewhere classified, left hip
    Billable
  28. M21.159
    Varus deformity, not elsewhere classified, unspecified hip
    Billable
  29. M21.16
    Varus deformity, not elsewhere classified, knee
    Header
    Inclusion terms 2

    Inclusion terms

    • Bow leg
    • Genu varum
  30. M21.161
    Varus deformity, not elsewhere classified, right knee
    Billable
  31. M21.162
    Varus deformity, not elsewhere classified, left knee
    Billable
  32. M21.169
    Varus deformity, not elsewhere classified, unspecified knee
    Billable
  33. M21.17
    Varus deformity, not elsewhere classified, ankle
    Header
  34. M21.171
    Varus deformity, not elsewhere classified, right ankle
    Billable
  35. M21.172
    Varus deformity, not elsewhere classified, left ankle
    Billable
  36. M21.179
    Varus deformity, not elsewhere classified, unspecified ankle
    Billable
  37. M21.2
    Flexion deformity
    Header
  38. M21.20
    Flexion deformity, unspecified site
    Billable
  39. M21.21
    Flexion deformity, shoulder
    Header
  40. M21.211
    Flexion deformity, right shoulder
    Billable
  41. M21.212
    Flexion deformity, left shoulder
    Billable
  42. M21.219
    Flexion deformity, unspecified shoulder
    Billable
  43. M21.22
    Flexion deformity, elbow
    Header
  44. M21.221
    Flexion deformity, right elbow
    Billable
  45. M21.222
    Flexion deformity, left elbow
    Billable
  46. M21.229
    Flexion deformity, unspecified elbow
    Billable
  47. M21.23
    Flexion deformity, wrist
    Header
  48. M21.231
    Flexion deformity, right wrist
    Billable
  49. M21.232
    Flexion deformity, left wrist
    Billable
  50. M21.239
    Flexion deformity, unspecified wrist
    Billable
  51. M21.24
    Flexion deformity, finger joints
    Header
  52. M21.241
    Flexion deformity, right finger joints
    Billable
  53. M21.242
    Flexion deformity, left finger joints
    Billable
  54. M21.249
    Flexion deformity, unspecified finger joints
    Billable
  55. M21.25
    Flexion deformity, hip
    Header
  56. M21.251
    Flexion deformity, right hip
    Billable
  57. M21.252
    Flexion deformity, left hip
    Billable
  58. M21.259
    Flexion deformity, unspecified hip
    Billable
  59. M21.26
    Flexion deformity, knee
    Header
  60. M21.261
    Flexion deformity, right knee
    Billable
  61. M21.262
    Flexion deformity, left knee
    Billable
  62. M21.269
    Flexion deformity, unspecified knee
    Billable
  63. M21.27
    Flexion deformity, ankle and toes
    Header
  64. M21.271
    Flexion deformity, right ankle and toes
    Billable
  65. M21.272
    Flexion deformity, left ankle and toes
    Billable
  66. M21.279
    Flexion deformity, unspecified ankle and toes
    Billable
  67. M21.3
    Wrist or foot drop (acquired)
    Header
  68. M21.33
    Wrist drop (acquired)
    Header
  69. M21.331
    Wrist drop, right wrist
    Billable
  70. M21.332
    Wrist drop, left wrist
    Billable
  71. M21.339
    Wrist drop, unspecified wrist
    Billable
  72. M21.37
    Foot drop (acquired)
    Header
  73. M21.371
    Foot drop, right foot
    Billable
  74. M21.372
    Foot drop, left foot
    Billable
  75. M21.379
    Foot drop, unspecified foot
    Billable
  76. M21.4
    Flat foot [pes planus] (acquired)
    Header
    Excludes1 1

    Excludes1

    • congenital pes planus (Q66.5-) Q66.5
  77. M21.40
    Flat foot [pes planus] (acquired), unspecified foot
    Billable
  78. M21.41
    Flat foot [pes planus] (acquired), right foot
    Billable
  79. M21.42
    Flat foot [pes planus] (acquired), left foot
    Billable
  80. M21.5
    Acquired clawhand, clubhand, clawfoot and clubfoot
    Header
    Excludes1 1

    Excludes1

    • clubfoot, not specified as acquired (Q66.89) Q66.89
  81. M21.51
    Acquired clawhand
    Header
  82. M21.511
    Acquired clawhand, right hand
    Billable
  83. M21.512
    Acquired clawhand, left hand
    Billable
  84. M21.519
    Acquired clawhand, unspecified hand
    Billable
  85. M21.52
    Acquired clubhand
    Header
  86. M21.521
    Acquired clubhand, right hand
    Billable
  87. M21.522
    Acquired clubhand, left hand
    Billable
  88. M21.529
    Acquired clubhand, unspecified hand
    Billable
  89. M21.53
    Acquired clawfoot
    Header
  90. M21.531
    Acquired clawfoot, right foot
    Billable
  91. M21.532
    Acquired clawfoot, left foot
    Billable
  92. M21.539
    Acquired clawfoot, unspecified foot
    Billable
  93. M21.54
    Acquired clubfoot
    Header
  94. M21.541
    Acquired clubfoot, right foot
    Billable
  95. M21.542
    Acquired clubfoot, left foot
    Billable
  96. M21.549
    Acquired clubfoot, unspecified foot
    Billable
  97. M21.6
    Other acquired deformities of foot
    Header
    Excludes2 1

    Excludes2

    • deformities of toe (acquired) (M20.1-M20.6-) M20.1 M20.6
  98. M21.61
    Bunion
    Header
  99. M21.611
    Bunion of right foot
    Billable
  100. M21.612
    Bunion of left foot
    Billable
  101. M21.619
    Bunion of unspecified foot
    Billable
  102. M21.62
    Bunionette
    Header
  103. M21.621
    Bunionette of right foot
    Billable
  104. M21.622
    Bunionette of left foot
    Billable
  105. M21.629
    Bunionette of unspecified foot
    Billable
  106. M21.6X
    Other acquired deformities of foot
    Header
  107. M21.6X1
    Other acquired deformities of right foot
    Billable
  108. M21.6X2
    Other acquired deformities of left foot
    Billable
  109. M21.6X9
    Other acquired deformities of unspecified foot
    Billable
  110. M21.7
    Unequal limb length (acquired)
    Header
    Notes 1

    Notes

    • The site used should correspond to the shorter limb
  111. M21.70
    Unequal limb length (acquired), unspecified site
    Billable
  112. M21.72
    Unequal limb length (acquired), humerus
    Header
  113. M21.721
    Unequal limb length (acquired), right humerus
    Billable
  114. M21.722
    Unequal limb length (acquired), left humerus
    Billable
  115. M21.729
    Unequal limb length (acquired), unspecified humerus
    Billable
  116. M21.73
    Unequal limb length (acquired), ulna and radius
    Header
  117. M21.731
    Unequal limb length (acquired), right ulna
    Billable
  118. M21.732
    Unequal limb length (acquired), left ulna
    Billable
  119. M21.733
    Unequal limb length (acquired), right radius
    Billable
  120. M21.734
    Unequal limb length (acquired), left radius
    Billable
  121. M21.739
    Unequal limb length (acquired), unspecified ulna and radius
    Billable
  122. M21.75
    Unequal limb length (acquired), femur
    Header
  123. M21.751
    Unequal limb length (acquired), right femur
    Billable
  124. M21.752
    Unequal limb length (acquired), left femur
    Billable
  125. M21.759
    Unequal limb length (acquired), unspecified femur
    Billable
  126. M21.76
    Unequal limb length (acquired), tibia and fibula
    Header
  127. M21.761
    Unequal limb length (acquired), right tibia
    Billable
  128. M21.762
    Unequal limb length (acquired), left tibia
    Billable
  129. M21.763
    Unequal limb length (acquired), right fibula
    Billable
  130. M21.764
    Unequal limb length (acquired), left fibula
    Billable
  131. M21.769
    Unequal limb length (acquired), unspecified tibia and fibula
    Billable
  132. M21.8
    Other specified acquired deformities of limbs
    Header
    Excludes2 1

    Excludes2

  133. M21.80
    Other specified acquired deformities of unspecified limb
    Billable
  134. M21.82
    Other specified acquired deformities of upper arm
    Header
  135. M21.821
    Other specified acquired deformities of right upper arm
    Billable
  136. M21.822
    Other specified acquired deformities of left upper arm
    Billable
  137. M21.829
    Other specified acquired deformities of unspecified upper arm
    Billable
  138. M21.83
    Other specified acquired deformities of forearm
    Header
  139. M21.831
    Other specified acquired deformities of right forearm
    Billable
  140. M21.832
    Other specified acquired deformities of left forearm
    Billable
  141. M21.839
    Other specified acquired deformities of unspecified forearm
    Billable
  142. M21.85
    Other specified acquired deformities of thigh
    Header
  143. M21.851
    Other specified acquired deformities of right thigh
    Billable
  144. M21.852
    Other specified acquired deformities of left thigh
    Billable
  145. M21.859
    Other specified acquired deformities of unspecified thigh
    Billable
  146. M21.86
    Other specified acquired deformities of lower leg
    Header
  147. M21.861
    Other specified acquired deformities of right lower leg
    Billable
  148. M21.862
    Other specified acquired deformities of left lower leg
    Billable
  149. M21.869
    Other specified acquired deformities of unspecified lower leg
    Billable
  150. M21.9
    Unspecified acquired deformity of limb and hand
    Header
  151. M21.90
    Unspecified acquired deformity of unspecified limb
    Billable
  152. M21.92
    Unspecified acquired deformity of upper arm
    Header
  153. M21.921
    Unspecified acquired deformity of right upper arm
    Billable
  154. M21.922
    Unspecified acquired deformity of left upper arm
    Billable
  155. M21.929
    Unspecified acquired deformity of unspecified upper arm
    Billable
  156. M21.93
    Unspecified acquired deformity of forearm
    Header
  157. M21.931
    Unspecified acquired deformity of right forearm
    Billable
  158. M21.932
    Unspecified acquired deformity of left forearm
    Billable
  159. M21.939
    Unspecified acquired deformity of unspecified forearm
    Billable
  160. M21.94
    Unspecified acquired deformity of hand
    Header
  161. M21.941
    Unspecified acquired deformity of hand, right hand
    Billable
  162. M21.942
    Unspecified acquired deformity of hand, left hand
    Billable
  163. M21.949
    Unspecified acquired deformity of hand, unspecified hand
    Billable
  164. M21.95
    Unspecified acquired deformity of thigh
    Header
  165. M21.951
    Unspecified acquired deformity of right thigh
    Billable
  166. M21.952
    Unspecified acquired deformity of left thigh
    Billable
  167. M21.959
    Unspecified acquired deformity of unspecified thigh
    Billable
  168. M21.96
    Unspecified acquired deformity of lower leg
    Header
  169. M21.961
    Unspecified acquired deformity of right lower leg
    Billable
  170. M21.962
    Unspecified acquired deformity of left lower leg
    Billable
  171. M21.969
    Unspecified acquired deformity of unspecified lower leg
    Billable

Sources of each column.

Instructions

At M21

Excludes1

  • acquired absence of limb (Z89.-) Z89
  • congenital absence of limbs (Q71-Q73) Q71 Q73
  • congenital deformities and malformations of limbs (Q65-Q66, Q68-Q74) Q65 Q66 Q68 Q74

Excludes2

  • acquired deformities of fingers or toes (M20.-) M20
  • coxa plana (M91.2) M91.2

Notes that also apply

Block M20-M25 instructions (Excludes2 1): printed on the block page.

Instructions for the group M00-M25 (Includes 1): printed on the chapter 13 page.

Chapter 13 instructions (Notes 1, Excludes2 10): printed on the chapter 13 page.

Index entries

  • Knock knee (acquired) → M21.06-
  • Bowleg(s) (acquired) → M21.16-
  • Bunion → M21.61-
  • Bunionette → M21.62-
  • Deformityvalgus NEC → M21.00
  • Cubitusvalgus (acquired) → M21.02-
  • Genuvalgum (acquired) (knock-knee) → M21.06-
  • Deformityvarus NEC → M21.10
  • Cubitusvarus (acquired) → M21.12
  • Genuvarum (acquired) (bowleg) → M21.16-
  • Deformityflexion (joint) (acquired) → M21.20
  • Flexiondeformity, joint → M21.20
  • Buniontailor's → M21.62-
  • Deformityhumerus (acquired) → M21.82-
  • Deformityjoint (acquired) NEC → M21.90
  • Deformitylimb (acquired) → M21.90
  • Deformityvalgus NECelbow → M21.02-
  • Deformityvalgus NEChip → M21.05-
  • Deformityvalgus NECknee → M21.06-
  • Deformityvalgus NECankle → M21.07-
  • Deformityvarus NECelbow → M21.12-
  • Deformityvarus NEChip → M21.15
  • Deformityvarus NECknee → M21.16-
  • Deformityvarus NECankle → M21.17-
  • Deformitylimb (acquired)flexion → M21.20
  • Deformitylimb (acquired)wrist drop → M21.33-
  • Deformitylimb (acquired)flat foot → M21.4-
  • Deformitylimb (acquired)clawhand → M21.51-
  • Deformitylimb (acquired)clubhand → M21.52-
  • Deformitylimb (acquired)clawfoot → M21.53-
  • Deformitylimb (acquired)clubfoot → M21.54-
  • Deformitylimb (acquired)unequal length → M21.70
  • Deformitylimb (acquired)specified type NEC → M21.80
  • Deformityjoint (acquired) NECelbow → M21.92-
  • Deformityjoint (acquired) NECshoulder → M21.92-
  • Deformitylimb (acquired)upper arm → M21.92-
  • Deformityjoint (acquired) NECwrist → M21.93-
  • Deformitylimb (acquired)forearm → M21.93-
  • Deformityjoint (acquired) NEChand → M21.94-
  • Deformitylimb (acquired)hand → M21.94-

24 more, longer entries are not listed; the search box finds them by word.

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