Prevalence of and factors associated with posterior tibial tendon pathology on sonographic assessment

Objective: To assess the frequency of and factors associated with supramalleolar posterior tibial tendon (PTT) pathology that often may be missed on sonography because of the limited field of view of ultrasound. Design: Retrospective cross-sectional study. Setting: Large academic center. Patients: Patients with medial ankle pain and tenderness and with normal radiographs who presented for sonographic assessment (n = 217). Methods: Two experienced musculoskeletal radiologists interpreted the studies by consensus. Main Outcome Measurement: PTT pathology. Results: Of the 217 patients, 33.2% had grade 1 PTT pathology (n = 72), 14.3% had grade 2 pathology (n = 31), and 2.8% had grade 3 pathology (n = 6). When stratified by location, 29.0% of patients (n = 63) had inframalleolar abnormalities, 11.5% had retromalleolar pathology (n = 25), and 11 patients had supramalleolar pathology (5.1%). Four patients had PTT subluxation or dislocation. Age was significantly associated with PTT pathology (P = .02). A higher proportion of patients with supramalleolar (81.8%) and retromalleolar (72.0%) PTT pathology were women compared with patients who had inframalleolar (57.1%) PTT pathology. A higher proportion of patients with supramalleolar and retromalleolar PTT pathology had grade 2 tears compared with those with inframalleolar PTT pathology (36.4% for supramalleolar, 44.0% for retromalleolar, and 22.2% for inframalleolar pathology). Conclusions: We present one of the largest studies on PTT pathology. PTT pathology can occur in the supramalleolar area, a region that often is not assessed on imaging. Although data are unavailable with regard to whether the natural history of supramalleolar PTT is different from that of other regions, patients with supramalleolar PTT pathology had more severe grades of tear and increased prevalence of tenosynovitis and were more often women. It is essential to recognize supramalleolar PTT pathology so that consequences of nontreatment such as medial arch collapse can be prevented.