Association of Cavovarus Foot Alignment With Peroneal Tendon Tears.

BACKGROUND: Although it is a widely accepted clinical principle that cavovarus deformity predisposes to peroneal tendon problems, there are limited data to support that assumption. This study tested the hypothesis that cavovarus is associated with peroneal tendon tears and evaluated which radiographic measures correlated with that association.

METHODS: A retrospective comparison of radiographic measures of cavovarus in 234 consecutive patients operatively treated for chronically symptomatic peroneal tendon tears was compared to a matched control group. Measures included calcaneal pitch, anteroposterior (AP) talometatarsal and talocalcaneal angles, and talonavicular coverage angle. A novel coordinate system analyzed midfoot and hindfoot components of cavovarus. Analysis of variance was used to compare cohorts, and a Tukey-Kramer test used to analyze 3 subgroups of brevis and longus tears, and concomitant tears.

RESULTS: The distribution of tears was 73% peroneus brevis, 8% longus, and 19% both tendons. Compared with controls, the study group, and subgroups, had multiple measures of increased cavovarus, including greater calcaneal pitch ( P = .0001), decreased AP talo-first metatarsal angle ( P = .0001), and increased talonavicular coverage angle ( P = .0001). Elevated medial longitudinal arch, and rotational changes in the radiographic profiles of the hindfoot were found with the coordinate system described by Yokokura.

CONCLUSION: This study found a statistically significant association of increased cavovarus deformity with peroneal tendon tears, compared to controls. It documented the relative incidence of tears of peroneus brevis, peroneus longus, and concomitant tears in a large surgical series. It demonstrated which simple radiographic angles and complex coordinate measurements of cavovarus deformity were significantly associated with peroneal tendon tears.

LEVEL OF EVIDENCE: Level III, retrospective comparative cohort study.