Pes planus after tibial osteotomy.

When 100 patients who had had a high tibial osteotomy for monocompartmental arthritis were reviewed, 15 were found to have evidence of neurological impairment. A severe symptomatic pes planus deformity of the ipsilateral limb had developed in 4 patients within months of surgery. Electromyographic results showed evidence of dysfunction in the territory of the posterior tibial nerve in all 4 patients, and, in 3 there was evidence of deep peroneal nerve damage. All had surgery for varus malalignment.