A Predictive Model for Gastrocnemius Tightness in Forefoot Pain and Intractable Plantar Keratosis of the Second Rocker.

BACKGROUND: Many people experience gastrocnemius tightness. Few studies demonstrate the relationship between gastrocnemius tightness and forefoot pathology. This study aimed to define the association between intractable plantar keratosis of the second rocker (IPK2) (also known as well-localized IPK or discrete keratosis) and metatarsalgia.

METHODS: The Silfverskiöld (ST) and lunge (LT) tests, used for measuring ankle dorsiflexion, were applied to diagnose gastrocnemius tightness. An instrument for measuring accurate performance and the force to be applied (1.7-2.0 kg of force to the ankle dorsiflexion) complemented the ST for clinical diagnosis and to obtain repeatedly reliable results (the authors apply force manually, which is difficult to quantify accurately).

RESULTS: Of 122 patients studied, 74 were used to devise a prediction model from a logistic regression analysis that determines the probability of presenting gastrocnemius tightness in each test (LT and ST) with the following variables: metatarsalgia, IPK2, and maximum static pressure (baropodometry). The IPK2 plays the principal role in predicting this pathology, with the highest Wald values (6.611 for LT and 5.063 for ST). Metatarsalgia induces a somewhat lower change (66.7% LT and 64.3% ST). The maximum pressure of the forefoot is equally significant (P = .043 LT and P = .025 ST), taking α < .05 as the significance level.

CONCLUSIONS: The results of this validation report confirm that a model composed of metatarsalgia, IPK2, and maximum pressure in static acts as a predictive method for gastrocnemius tightness.