Fractures of the Lower Leg and Ankle | Blog

Fractures of the Lower Leg and Ankle

This Blog concerns itself with fractures involving the lower leg and ankle, which can be rather complicated and complex. It will not address fractures of the patella or proximal tibia and/or fibula, but starts with the shafts of these bones, then on distally to include the ankle. Also, it does not include the coding for Salter-Harris Fractures of the lower leg and ankle region. (See the Blog on Epiphyseal/Physeal Fractures.)

As reminder, there are Defaults in the coding of fractures, which are that fractures are deemed to be closed unless clearly described as open, and are displaced unless clearly is designated as undisplaced/non-displaced. As it pertains to whether a fracture is open or closed when coding for fractures of two bones, there becomes an issue as to whether the term “open” means that the fractures of each/both bones are “open” or not. It is possible that one of the two bones may be an “open” fracture, whereas the other fractured bone may not, such that it could be possible to have to code one as being “open” and the other as being “closed.” Therefore, it is important in the documentation of the description of the fractures that it be noted that each bone is either an “open” or “closed” fracture.

It is also important to remember that there are no codes in ICD-10 that include fractures of both the tibia and fibula, as there were in ICD-9. The exception to this, of course, is the coding of fractures of the ankle where a single code may cover fractures of both bones, such as the bimalleolar fracture. As such, both the tibia and fibular fractures have to be coded separately and individually, and each would require a 7th Character for each. I am not aware of any rule that says that the 7th Characters have to be the same for both fractures (see the discussion in the previous paragraph). In addition to the Initial Encounter, this would also apply to the 7th Characters for Subsequent Encounters. As it concerns 7th Characters, the full spectrum of possibilities for fractures of the lower leg and ankle, except for Torus and Epiphyseal fractures, both of which are considered to be closed fractures, thereby limiting the number of 7th Characters for use. Again, I refer to my Blog regarding Epiphyseal/Physeal Fractures.

I will start at the level of the Tibial and Fibular shafts, then progress distally to the ankle. The Code Set S82.2 is for fractures of the Tibial Shaft, and S82.4 is for fractures of the Fibular Shaft. The 5th Character determines the fracture pattern (transverse, oblique, etc.), and the 6th Character designates laterality and whether the fracture is displaced or non-displaced (1: Displaced Right, 2: Displaced Left, 4: Non-displaced Right, and 5: Non-displaced Left). The 7th Character, as usual, is the full spectrum of those for Initial and Subsequent Encounters. Interposed between S82.2 and S82.4 is Code Set S82.3 : Fracture of the lower end/distal tibia, which Excludes bimalleolar fracture, isolated medial malleolar fracture, Maisonneuve fracture, pilon fracture, trimalleolar fracture, and periprosthetic fracture around an ankle prosthesis. This Code Set does include Torus Fracture of the distal tibia (S82.31 ), which is always considered to be a closed fracture, and for which the 7th Characters can only be A, D, G, K, P, or S. There is also code S82.39 _: "Other" fracture of the distal tibia. As usual, “Other” means "none of the above.”

For some reason, the fractures of the medial and lateral malleoli have separate Code Sets. S82.5 is for an isolated fracture of the Medial Malleolus, i.e. not part of a more complex ankle fracture and injury. It Excludes pilon fractures and Salter-Harris Types III and IV of the distal tibia. S82.6 is for an isolated fracture of the Lateral Malleolus, and Excludes pilon fracture of the distal tibia. The 5th Characters for these codes are the same as the 6th Characters for the S82 codes as described above for laterality and displacement. The 6th Character for these code sets are the space holder X. Apparently, the 7th Character for use are the full range of 7th Characters. For some reason, these isolated fractures of the malleoli are separated from other ankle fractures, which will be covered further on.

There is a Code Set S82.8 : "Other" fractures of the lower leg, which includes a Torus Fracture of the distal fibula (S82.82 _), which is always considered to be a closed fracture, and therefore has limited 7th Characters for Initial and Subsequent Encounters coding. Unfortunately, included in this code set are other fractures that involve the distal tibia and the fibula, which will be discussed in the following paragraphs.

In addressing Ankle Fractures, which are part of the S82.8 Code Set, there are three recognized Malleoli: the Medial, Lateral, and Posterior. The Medial and Posterior Malleoli are part of the distal tibia, whereas the Lateral Malleolus is part of the fibula. As such, the term and code for Bimalleolar Fracture (S82.84 ) can include any combination of two of these three, with the possibilities being medial and posterior, medial and lateral, or lateral and posterior. One Code Set covers all three possibilities. In common Orthopedic terminology/vernacular, when we speak of a Bimalleolar Fracture we are usually talking about fractures of the medial and lateral malleoli. The term Trimalleolar describes a fracture involving all three (S82.85 _).

Another fracture included in the S82.8 Codes Set is Maisonneuve’s Fracture (S82.86 ), which is a combined fracture of the lower leg and ankle. It includes a spiral fracture of the proximal fibular shaft, tearing of the interosseous membrane (ligament), disruption of the distal Tibio-fibular joint (Syndesmosis) and its ligamentous support, but also there is dislocation or subluxation of the talus relative to the distal tibia. This can be the result of either a fracture of the medial malleolus with displacement, or rupturing/tearing of the medial collateral ligament of the ankle (Deltoid). Although the Code Set may be inclusive of all of these elements, I would be careful about assuming that. I would tend to code the medial malleolar fracture or the medial ligamentous injury separately, depending on the which is present. However, ligamentous injuries of the ankle, including subluxation, dislocation, etc., are not included in the S82 Code Set, but are located in the S93.0 Code Set, which is for Subluxation and/or Dislocation of the ankle. Since this particular Code Set does not differentiate the Tibiotalar joint from the Distal Tibio-fibular joint, nor does it exclude one or the other, I would use this Code Set to cover both the Distal Tibio-fibular joint and Tibiotalar joint involvement. In the presence of a Fracture-Dislocation/Subluxation of the ankle, I would not use the codes from the S93.4 Code Set for "Sprain of the Ankle.” A dislocation/subluxation of a joint requires that ligamentous disruption and injury to have occurred, so coding both is not really warranted, i.e. coding a dislocation/subluxation would include the requisite ligamentous “sprain.” A Dislocation and/or Subluxation is the “ultimate” Sprain.

The code S82.87 is for a Pilon Fracture of the distal tibia. This is a fracture of the distal tibial metaphysis and the weightbearing articular surface/portion of the distal tibia. It can be of varying degrees of severity. The medial malleolus is usually a portion of, or one of the fracture fragments involved. Interestingly the code for the Pilon fracture includes the associated medial malleolar fracture, but an isolated medial malleolar fracture does not include a pilon fracture. As such, if there is a medial malleolar fracture fragment, it would not need to be coded separately as it would be included in S82.87 . This fracture frequently has an associated fracture of the distal fibula, anywhere from the lower shaft to the lateral malleolus, but the fibular fracture is not included in S82.87 . Therefore, the fibular fracture would have to be coded separately from S82.6, S82.83, or S82.49, whichever is the most accurate/specific.

S82.89 is for “Other” fractures of the lower leg." “Other,” as usual means "none of the above.” I would include in this code Pott’s Fracture, which also goes by the name of Dupuytran's Fracture. This is very similar to Maisonneuve's Fracture, but the fracture involving the fibula is most often in the lower shaft, proximal to the ankle joint, and is not necessarily a spiral fracture, but could be of a different type fracture pattern. In addition, the other elements or components include disruption of the interosseous membrane, injury to the Distal Tibio-fibular joint (Syndesmosis) and its ligamentous supports, and subluxation or dislocation of the talus relative to the tibia, resulting from either a displaced medial malleolar fracture or tearing of the medial collateral (Deltoid) ligament of the ankle. Again, I would not assume that this one code will cover all of the elements described such that I would recommend additionally coding the medial malleolar fracture or the dislocation/subluxation of the ankle, which ever the case may be. I would refer back to the discussion of coding for Maisonneuve Fracture above.

Fracture-Dislocations (including Subluxation) of the Ankle are common and reflect a severe injury. These can involve multiple bone fractures or a combination of fractures and ligamentous injuries. The Talus can be shifted laterally, posteriorly, or a combination of both. The “Traditional" Bimalleolar (medial and lateral) Fracture usually goes more laterally than posteriorly. The more "Nontraditional" Bimalleolar Fracture (lateral and posterior malleoli) could go laterally, posteriorly, or both, but in order to do so would require a ligamentous disruption of the medial collateral ligament (Deltoid). Also, in order for the talus to go posteriorly, there would have to be a fairly large posterior malleolar fracture extending deep into the posterior tibia and ankle joint. The Maisonneuve and Pott’s/Dupuytran's Fractures previously discussed would also fall into the general category of Fracture-Dislocations of the ankle. The basic codes for the fracture portion of these injuries would be in the S82 Code Set, but the dislocation/subluxation/ligamentous injury would need a code from the S93.0 Code Set. As previously discussed, the codes for Ankle “Sprain" (S93.4 ) would not really apply. This means that two codes would be necessary to complete the diagnosis coding, a fracture code from the S82.5, 6, or 8 Code Sets, and a code from the S93.0 Code Set to cover the dislocation/subluxation. Interestingly, the allowable 7th Character codes for the S93.0 Code Set are only A, D, and S, which would not allow for the possibility of an open dislocation. Although the vast majority of these injuries are closed, open fracture-dislocations are not rare. That leaves the dilemma of how to code for an open fracture-dislocation. My best recommendation is to use an open fracture 7th Character (B or C for the Initial Encounter, and E, F, H, J, M, N, Q, R for Subsequent Encounter). In my experience, most of the open fracture-dislocations would be of the Gustilo I or II wound types, but Gustilo IIIA, B, and C are not out of the realm of possibility. In ICD-10, dislocations of joints are all considered to be closed such that the 7th Characters for open injuries and fractures do not apply. For an open dislocation, I have been advised that it would be coded as an Open Wound with a Foreign Body, which in the case of an ankle injury, would be S81.82 _ with 7th Character of A, D, or S. The “Foreign Body” portion of this would be the end of the bone that presents itself in the wound.

Needless to say, coding fractures of the lower leg and ankle can be complex and messy, and may require multiple codes to achieve the requisite “specificity" to satisfy ICD-10.

Posted in Coding Blogs on Nov 09, 2016

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