Primary metatarsalgia: the influence of a custom moulded insole and a rockerbar on plantar pressure.

The effects of a custom moulded insole and a rockerbar on peak pressure and force impulse as well as on pain scores in subjects with a history of metatarsalgia were studied. In addition the subjects' preference for the type of intervention was determined. Forty-two subjects with a history of primary metatarsalgia were selected. They were all provided with the same brand of extra depth shoes with a ready made insole. The effect of custom moulded insoles, a rockerbar and the interaction between the two interventions were studied by testing the four possible combinations: ready made insole without a rockerbar, ready made insole with a rockerbar, custom moulded insole without a rockerbar and custom moulded insole with rockerbar. At the most important region, the central distal forefoot, a rockerbar caused a decrease in force impulse of 15.1% and a decrease in peak pressure of 15.7%. The custom moulded insole produced a decrease of 10.1% in force impulse and of 18.2% in peak pressure. Pain scores were significantly lower for interventions with a custom moulded insole, while the rockerbar showed no influence on pain scores. Subjects with pain preferred a custom moulded insole more often than subjects without pain. Decrease of peak pressure or force impulse was not correlated to pain scores. The use of either a custom moulded insole or a rockerbar produced an important decrease of peak pressure and force impulse at the central distal forefoot and, therefore, either is suitable in any situation which a decrease of pressure is vital.