2019 年 38 巻 4 号 p. 441-446
Background: Previously, we explained the correlation between the Takakura-Tanaka classification of radiographic staging and bone marrow edema (BME). We illustrated the feasibility of estimating the BME onset in the talocrural joint based on the radiographic alignment to elucidate the pathophysiology of ostearthritis (OA) using magnetic resonance imaging (MRI). This study focused on the subtalar joint and investigated the correlation between talar lateral process impingement (TLPI) and alignment of the foot and ankle based on radiographic findings. In addition, we extensively investigated patterns of BME.
Methods: We examined 30 feet of 30 patients who were diagnosed with ankle OA and who underwent MRI at our hospital. We assessed alignment radiographically by evaluating the tibial anterior surface angle (TAS), tibial lateral surface angle (TLS), lateral talo-first metatarsal angle (LTMT), and the tibial axis-talar ratio (T-T ratio). Furthermore, we assessed the BME frequency in the talocrural, subtalar, and Chopart joints and their correlation with TLPI in MRI and plain radiograph results.
Results: The TLPI onset increased with the severity of the Takakura-Tanaka classification stage. The TLPI (+) group exhibited a significantly lower TLS angle, but a significantly higher LTMT angle. Moreover, it was associated with TLPI and BME occurrence in the posteromedial side of the talocrural joint (area 3’). Furthermore, the disease group was categorized into three stages according to the occurrence pattern of TLPI and area 3’. The frequency of BME also increased as the stage increased.
Conclusion: This study has revealed that there is an association with BME occurrence in TLPI and area 3’; this result could be a risk factor to generate extensive BME. Consequently, this novel finding indicates that a potential prognostic tool of the severity of clinical symptoms can be used.
