Diagnostic efficacy of ultrasonography in stage I posterior tibial tendon dysfunction: sonographic-surgical correlation.

The purpose of this study is to evaluate the diagnostic efficacy of ultrasonography in stage I posterior tibial tendon dysfunction. Fourteen of the 17 consecutive patients who underwent tenosynovectomy for stage I posterior tibial tendon dysfunction were included in this study. The preoperative diagnosis was based primarily on the clinical suspicion of dysfunction, which was confirmed by ultrasonography. Two measurements were obtained at the midpoint between the insertion site and the medial malleolus in both feet of the 14 patients: the diameter of the posterior tibial tendon and the diameter of the tendon sheath measured from its inner walls. The mean diameter of the tendon was 4.61 +/- 0.50 mm and that of the tendon sheath in the symptomatic foot was 7.24 +/- 0.75. In the unaffected foot, the mean diameter of the tendon was 3.30 +/- 0.34 mm and that of the tendon sheath was 3.64 +/- 0.35 mm, respectively. In the symptomatic tendon, the increase of peritendinous space was significantly higher than the increase in the tendinous portion (P < 0.0001). Surgical findings proved the accuracy of diagnosis in all patients. Although many cases of stage I posterior tibial tendon dysfunction remain undiagnosed owing to the mild clinical symptoms, this series indicates that ultrasonography is a valuable adjunctive diagnostic tool in the clinical examination and assists in achieving an accurate diagnosis of stage I posterior tibial tendon dysfunction, allowing early treatment.