Characterization of patients with primary peroneus longus tendinopathy: a review of twenty-two cases.

Between 1985 and 1996 we treated 22 patients with a diagnosis of PLT which was confirmed by MRI and/or surgery. This review identifies the shared clinical traits and associated pathology of our patients. Clinically, 82% of the patients had a cavo-varus hindfoot position. This finding was supported by measurements of the calcaneal pitch angle and the calcaneal-lst metatarsal angle which both showed the patients in this study to be in the 90th percentile for the general population for arch height. The combined MRI and surgical findings revealed injury to the peroneus longus at the cuboid notch in 17 of 22 cases. The subgroup of surgical findings demonstrated that all 6 complete tears occurred at the cuboid notch, while 8 of 9 (89%) of the partial tears involved the region of the lateral calcaneal process. In addition, the surgical findings showed 7 of the cases (33%) to have associated peroneus brevis tendon involvement, with an increased incidence when the longus pathology occurred at the cuboid notch. The findings predicated by MRI correlated well with the surgical findings, but there was a tendency for MRI to predict a more severe level of pathology. A grading system developed to compare the MRI and surgical findings is presented. This study facilitates making the diagnosis of PLT by drawing attention to the common characteristic of the cavo-varus foot position and the common locations of tendon injury.