Development of Contiguous-Joint Arthritis After Pilon Fracture

The clinical implications of operatively fixed pilon, talar, and calcaneal fractures lie in the long-term observation of posttraumatic arthritis of the injured joint. For example, a review found an approximately 39% rate of posttraumatic arthritis after fractures of the tibial plafond1. Specifically, radiographic appearance of subtalar arthritis after intra-articular calcaneal fractures has been noted in >21% of patients at 17 months2. A prospective multicenter observational case study of 116 enrolled patients with a pilon fracture evaluated the extent of cartilage damage intraoperatively as well as radiographic evidence of osteoarthritis and functional outcomes (using the Foot and Ankle Ability Measure [FAAM] subscales for activities of daily living and sport activities) at 2 years after injury in the 56% of patients who had not been lost to follow-up. Initial cartilage damage was associated with early to mid-term osteoarthritis development and worse functional outcomes3. In contrast, little has been written about the natural history of the contiguous joint after an isolated traumatic injury to a joint—such as the contiguous subtalar joint after operative fixation of a pilon fracture, as studied by Joshi et al. Information regarding the natural history is critical for patient prognostication—such as the potential for further degenerative changes leading to the development of accelerated radiographic subtalar changes and/or clinical symptoms. Joshi et al. provide insight regarding the development of subtalar arthritis in a series of 474 operatively treated pilon fractures in adults, with the exclusion of patients who had a concurrent talar or calcaneal fracture. When patients were grouped according to the time from the injury to the last imaging studies (<12, 12 to 24, 25 to 48, and >48 months), the mean Kellgren-Lawrence (K-L) grade of subtalar osteoarthritis on radiographs was significantly higher in both of the groups with >24 months of follow-up compared with the group with <12 months: by 0.34 (95% confidence interval [CI], 0.03 to 0.66; p = 0.04) for 25 to 48 months and by 0.37 (95% CI, 0.08 to 0.66; p = 0.01) for >48 months. Although the study demonstrated increasing radiographic subtalar joint arthritis over time, it did have some limitations. These include the absence of patient-reported outcomes and the absence of an assessment of the initial subtalar injury by either intraoperative observations or advanced imaging. Other limitations involve the variability in the mechanisms related to the development of subtalar arthritis alone as well as the inability to determine the severity of the initial pilon fracture, which may mitigate or worsen the development of posttraumatic subtalar arthritis. Patients with a fracture involving the articular surface of the calcaneus, talus, or pilon, with or without malalignment, need to be informed that a substantial risk of subtalar arthritis exists. Even if the articular reduction and anatomic alignment are performed optimally, that may not prevent the development of additional morbidity, such as subtalar arthritis. One other key point involves the difference between radiographic changes and clinical symptoms of arthritis. Often, early radiographic changes are observed but clinical symptoms occur many years later. This study provides critical insight into the effect of time, and patients need to be warned and educated about the development of posttraumatic subtalar arthritis after operative fixation of a pilon injury. Such arthritic changes over time may become radiographically evident beyond the first 2 years and subsequently become clinically relevant. In conclusion, the incidence of subtalar joint arthritis leading to additional morbidity is very high after fractures involving joints about the hindfoot (i.e., calcaneal, talar, or pilon fractures). As demonstrated by Joshi et al., it is reasonable to expect an elevated risk of subtalar arthritis after operative fixation of a high-energy pilon fracture caused by an axial load, but the precise incidence is difficult to ascertain due to the absence of patient-reported outcomes in their study. The incidence of posttraumatic arthritis after lower-energy extra-articular ankle fractures is less well defined in the literature, but it is probably lower than the incidence after a high-energy pilon fracture. A need exists for additional studies with long-term follow-up (over 5 to 10 years) that involves routine radiographs of the subtalar joint as well as clinical outcomes after operative fixation of pilon fractures. Furthermore, studies should stratify by fracture severity and assess the effects of articular comminution of the pilon fracture, reduction quality, and the initial extent of subtalar involvement.