Knee Pain and ICD-10 Continued

Intra-operative and Post-procedural Complications and Disorders of the Musculoskeletal System, not elsewhere classified (M96):

Unfortunately, orthopedic surgical procedures in and around the knee do not always go as planned, and complications can occur which could result in increased acute postoperative pain as well as chronic residual knee pain.

  • M96.6 _ _: Fracture of bone following/during insertion of orthopedic implant: This includes prostheses and internal fixation implants. This particular complication would be one that occurred at the time of the procedure, and is not a late effect. The 5th Character would be 6 for femur, and 7 for the proximal tibia and fibula. The 6th Character would be for laterality.

  • M96.8: Other Intra-operative and Post-procedural Complications and Disorders of the Musculoskeletal System, not elsewhere classified: This Includes:

    • M96.810: Intra-operative Hemorrhage and/or Hematoma of a musculoskeletal structure complicating (during) a musculoskeletal procedure
    • M96.820: Accidental Puncture and/or Laceration of a Musculoskeletal Structure during a Musculoskeletal Procedure
    • M96.830: Post-procedural Hemorrhage of a Musculoskeletal Structure following a Musculoskeletal System Procedure
    • M96.840: Post-procedural Hematoma of a Musculoskeletal Structure following a Musculoskeletal Procedure
    • M96.89: "Other" Intra-operative and/or Post-procedural Complications of the Musculoskeletal System such as pain and/or instability of the joint secondary to removal of a prosthesis.

Q Codes: Congenital Malformations and Deformations of the Musculoskeletal System (Q65-Q87):

These are abnormalities which should be identified and treated at birth and/or in early childhood, and which are not likely to cause knee pain in a small child. But if identified and treated, or not, they could result in knee pain in adolescence and into adulthood.

  • Q68: Other Congenital Musculoskeletal Deformities:
    • Q68.2: Congenital Deformity of the Knee which includes Congenital Dislocation of the knee and Congenital Recurvatum.
    • Q68.3 (femur) and Q68.4 (tibia and fibula): Congenital Bowing of the bones of the legs. The residual deformity of the leg at the knee joint can result in knee pain problems. However, most of these tend to correct with treatment or spontaneously with growth.
    • Q68.6: Discoid Meniscus: This can cause knee joint pain, clicking, popping, or snapping in a growing child. This type of meniscus may tear at some later time in life resulting in knee pain, and require surgical treatment.
  • Q74.1: Congenital Malformation of the Knee: This Includes a variety of other problems such as absence of the patella, congenital patellar dislocation, congenital genu valgum or varum, or a rudimentary patella.

R Codes: Symptoms, Signs and Abnormal Clinical and Laboratory Findings, not elsewhere classified (R00-R99)

For practical purposes, none of the codes in this category are relevant or specific to knee pain.

S Codes: Injury and Certain Other Consequences of External Causes:

These are codes that could be used when a patient presents with "Acute Knee Pain." Not everybody that injures their knee necessarily ends up in the emergency room as the patient may not have thought the "traumatic incident" was of sufficient magnitude to warrant immediate care. They might have considered it a minimal or mild incident at the time, and just gone about their business as usual, only to have the pain or other symptoms persist rather than getting better as they thought that it would. Some of these may occur in children and adolescents who consider themselves "indestructible." Coding for these injuries at the knee area would come from the S72.4 through S89.2 codes.

  • S72.4: Fracture of the Lower End/Distal Femur: Of the codes in this Code Set, the ones that I would consider applicable would be:
    • S72.42 _ _: Lateral Femoral Condyle;
    • S72.43 _ _: Medial Femoral Condyle; and
    • S72.44 _ _: Distal/Lower Femoral Epiphysis which Excludes Salter-Harris Type I epiphyseal fractures of the lower end of the femur (S79.11 _ ), but Includes all other types of Salter-Harris epiphyseal fractures. It must be noted that with the exception of the foot and toes, epiphyseal/physeal fractures are all considered to be closed. Evidently, Salter-Harris Type I fractures are not only considered closed, but non-displaced. Therefore, for all other Salter-Harris Types, it requires 2 codes: S72.44 _ _, and one from S79.1. The distal femur is the only place that I have found this unusual circumstance. For the S72.44 code, the 6th Character designates displacement and laterality: 1: Displaced right, 2: Displaced left, 4: Non-displaced right, and 5: Non-displaced left. These are codes that require 7 Characters, but are limited to only those for closed fractures.
  • S76: Injury of the muscle, fascia, and/or tendons of the hip and thigh: Any trauma, even if relatively mild, to the soft tissues of the lower thigh and knee region could result in knee pain including:
    • S76.1 _ _ _: Quadriceps and Patellar Tendon,
    • S76.2 _ _ _: Abductor Muscles,
    • S76.3 _ _ _: Posterior muscle group, and
    • S76.8 _ _ _: Injury of Other specified muscles.
    • For these injuries, the 5th Character is 1 for "Strain," and 9 for "Other." The 6th Character is for laterality. Again, these are 7 Character codes, limited to A, D, or S.
  • S82: Fracture of the lower leg: The codes of this Code Set that might be pertinent to relatively minor injuries would be:
    • S82.01 _ _: Osteochondral Fracture of the Patella
      • (6th Character: 1: Displaced right, 2: Displaced left, 4: Non-displaced right, and 5: Non-displaced left),
    • S82.09 _ _: Other Fracture of the Patella (6th Character for laterality).
    • S82.1: Fracture of the upper/proximal tibia (which does not include the proximal fibula) Of particular interest in this Code Set are:
      • S82.11 _ _: Fracture of the Tibial Spine, which is an intra-articular fracture of the tibia
      • S82.12 _ _: Lateral Tibial Plateau
      • S82.13 _ _: Medial Tibial Plateau
      • S82.15 _ _: Tibial Tuberosity
      • S82.16 _ _: Torus Fracture of the Proximal Tibia.
      • Except for the Torus fracture, the 6th Characters for these codes are: 1: Displaced right, 2: Displaced left, 4: Non-displaced right, and 5: Non-displaced left.
      • For the most part, these particular fractures are going to be the result of more significant trauma, but in this day and age, anything is possible.
    • S82.8: Other Fractures of the Lower Leg: This includes:
      • S82.81 _ _: Torus Fracture of the Proximal Fibula, and
      • S82.83 _ _: Other Fracture of the Upper Fibula.
      • The 6th Character is for laterality. The 7th Character allows only for closed fractures, and include only A, D, and S.
  • S83: Dislocation and Sprain of the Knee Joint and Ligaments: These codes Include ligament avulsion, traumatic hemarthrosis, traumatic subluxation of the joint, and ligamentous tears. These Exclude(1) patellar derangements (M22.0-M22.3), patellar tendon injury (S76.1), internal derangement of the knee (M23), old and/or pathologic dislocation of the knee, and recurrent dislocation of the knee. Again, some of the problems in this category could result from relatively mild trauma and not result in emergency room visits, but could show up several days later as acute pain that didn't get better and go away.
    • S83.01 _ _: Lateral Subluxation and Dislocation of the Patella
    • S83.09 _ _: "Other" Subluxation and Dislocation of the Patella
    • Both of these would be considered Acute Patellar Instability. In particular, subluxation of the patella could result from a minor injury. Dislocations take a much more significant episode of trauma, and are likely to show up in the Emergency Room. For Subluxation, the 6th Character is for laterality.
    • S83.2: Tear of the Meniscus, Current Injury or Acute: This Code Set with 5th Characters of 1 through 8 covers a multitude of different meniscal tear types, medial and lateral.
    • S83.3 _X _: Tear of the Articular Cartilage of the Knee: This would apply to an articular cartilage injury without involvement of the subchondral bone (osteochondral fracture). This could occur to the patella, femur, and/or tibia.
    • S83.4 _ _ _ : Sprain of the Collateral Ligaments of the Knee: For the most part, these do require a fairly significant traumatic episode, but mild sprains can occur from lesser injuries, most often the medial collateral ligament.
    • S84: Injury of the nerves at the lower leg level: About the only one that I would consider in this grouping of minor injuries would be:
      • S84.2 _X _: Cutaneous Sensory Nerve at the Lower Leg Level. I would tend to put Traumatic Neuritis of the Infrapatellar Branches of the Saphenous Nerve in this Code Set because it does present as knee pain. This often occurs secondary to blunt trauma such as a contusion to the anterior-medial knee. Again local pain and tenderness, as well as an area of numbness, tingling, or paresthesias across the front of the knee would be how it presents. I would use this code for an acute or current situation, but if it is more chronic than I would refer back to M79.2: Neuralgia/ Neuritis NEC, as previously discussed.
    • S89.0 _ _ _: Epiphyseal Fracture of the Proximal Tibia: This covers all the types of Salter-Harris fractures, but does not include in the coding anything about displaced versus non-displaced. The 5th Character denotes the Salter-Harris Types: 1: Type I, 2: Type II, 3: Type III, 4: Type IV, and 9: "Other" Type. The 6th Character denotes laterality. The 7th Characters are limited to those for closed fractures (A, D, G, K, P, S).
    • S89.2 _ _ _: Epiphyseal Fracture of the Proximal Fibula only includes Salter-Harris Types I and II, and "Other" epiphyseal fractures of the proximal fibula. The 5th Character denotes the SH Type: 1 for Type I, 2 for Type II, and 9 for "Other". The 6th Character denotes laterality, and the 7th Character is limited to those for closed fractures (A, D, G, K, P, S).

G Codes: Diseases of the Nervous System (G00-G99):

  • For practical purposes, there are not any of these Codes that are going to be a primary cause of "knee pain." The G89 Codes: Pain, not elsewhere classified, Excludes(2) Site Pain (M25.56), and pain from prostheses (T84.8 codes). The use of these has been discussed in another Blog regarding Pain Coding. These can be used as adjunct/supplemental codes for Site of Pain (M25.56 for the knee joint) if it fits into the category of G89.11: Acute pain due to or secondary to trauma; G89.18: Other acute post-procedural pain; G89.21: Chronic pain secondary to trauma; G89.28: Other chronic post-procedural pain; and G89.3: Neoplastic pain, acute or chronic. These codes used as adjunct codes help clarify the circumstances surrounding the patient's knee pain. I would not find them particularly useful in the Pain Management situation since patient's with knee pain are rarely sent to Pain Management Specialists.

This is a lengthy Blog regarding Knee Pain and how I assess this topic in relation to ICD-10 coding. I have tried to bring out some of the controversies in terminology, vernacular, and term usage that appear in the language of Orthopedic Surgeons, discuss and resolve them as best I can, and translate them into useful information for Coders.

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