The Effect of a Leveling Procedure for Addressing Bony Step-off Following Medial Displacement Calcaneal Osteotomy

CATEGORY: Hindfoot; Other INTRODUCTION/PURPOSE: Due to the nature of the medial displacement calcaneal osteotomy (MDCO), bony step-off at the osteotomy site is inevitable and can lead to lateral prominence pain. Theoretically, this bony prominence can lead to irritation of the peroneal tendon, sural nerve, and overlying skin resulting in pain and discomfort. While these symptoms have been loosely described in the literature, the incidence and prevention are largely unexplored. The purpose of this study is to investigate the incidence of lateral prominence pain after MDCO as well as the efficacy of a leveling procedure (LP) as a preventive technique. METHODS: We retrospectively identified 175 feet in 160 patients who underwent MDCO from 2016 to 2018. Of the 175 feet, 102 underwent MDCO with LP, and 73 without LP. LP was performed after calcaneal fixation by flattening the residual bony prominence using rongeur and bone impactor (Figure 1). Lateral prominence symptoms were defined as pain present at 12 month follow-up after MDCO, either 1) over the lateral prominence on direct contact with the floor or footwear, or 2) associated with callus formation over the osteotomy site due to continued irritation. The overall incidence of lateral prominence symptoms after MDCO and the incidence with or without LP were investigated. The relationship between the amount of calcaneal displacement and the occurrence of lateral prominence pain with or without LP was also analyzed. RESULTS: The overall incidence of lateral prominence was 12.6% (22 of 175): 4.9% (5 of 102) in patients who underwent LP and 23.3% (17 of 73) in patients who did not undergo LP (p<0.001, Figure 2). In patients who did not undergo LP, a significant correlation was observed between incidence of lateral prominence symptoms and the amount of calcaneal displacement (p=0.013). This correlation was not observed in patients who underwent MDCO with LP (p=0.617). Six patients (one who had LP, five who did not have LP) underwent ostectomy as a secondary procedure to relieve symptoms at average 11.2 months (range, 8- 14) after the index surgery. CONCLUSION: It is important to address the bony step-off following MDCO procedure, as failure to do so may result in lateral prominence pain postoperatively. We demonstrate that a leveling procedure to remove the step-off yields promising results. Therefore, we suggest concomitant LP especially when a larger amount of correction is needed in performing MDCO.