In this study, we have shown that by the application of a modified, “straight” osteotomy through a minimally invasive approach we were able to correct the IMA and HVA in HV patients and, simultaneously, reduce the laterally displaced sesamoid bones into a non-pathological position. The modified osteotomy enabled us to address the three-dimensional configuration of the deformity and to correct its rotational aspect. As a result, more effective sesamoid reduction was achieved as compared with open chevron osteotomy or the original V-shaped MICA.
The importance of MT1 rotation during HV surgery has gained attention over the years.[17] Residual postoperative lateral displacement of sesamoids has been previously associated with HV recurrence,[10–12, 17] walking pain and arthritis.[14] Accordingly, several attempts have been made to correct the rotational element of the HV deformity and reduce the sesamoid bones into their natural position. Nyska et al.[18] studied different Ludloff osteotomy angles in order to find the optimal cut in which a correction of the pronation could be obtained. Wegner et al.[17] proposed an osteotomy technique that aimed to address the three-dimensional complexity of the HV deformity by a proximal rotational metatarsal osteotomy (PROMO). Okuda presented a proximal supination osteotomy that would simultaneously correct both the varus and the pronation of the MT1.[19] Although effective, these methods were described as open surgery techniques, thus lacking the benefits of the minimally invasive approach.
The minimally invasive technique that was introduced by Vernois and Redfern[9] is composed of three basic elements: A percutaneous V-shaped distal osteotomy, a lateral displacement of the head and a fixation of the new fragment configuration. These steps can be accompanied by a bunion osteo-resection and an akin osteotomy, and are conducted via skin cuts that are several millimeters long. The advantages of a minimally invasive technique are lower morbidity and shorter recovery time, less pain, and a better range of motion of the metatarsophalangeal joint. [5] In addition, since the skin cuts are minimal, there are less skin compilations and smaller scars.[20] The V-shaped osteotomy[9] enables to correct both mild and severe deformities, but it restricts the surgeon to a single-plane correction. The derotation of the MT1 head and, thereby, sesamoid position correction are not possible in cases where the metatarsophalangeal center of rotation shift was insufficient for sesamoid reorientation. The modification that we describe in this article eliminates the restriction that was formed by the V-shaped osteotomy and allows the correction of sesamoid bone position by a derotation of the MT1 head. In this series of 53 patients, the straight osteotomy was found to be the only technique by which we obtained a successful sesamoid reduction. This method allowed us to combine the benefits of minimally invasive technique with the possibility to correct the three-dimensional HV configuration.
The V-shaped osteotomy offers two main advantages. First, the V shape creates a larger contact area between the two bone fragments, as compared with a straight cut. Moreover, the V-Y is presumed to be a more stable configuration compared with two flat-shaped bones, which could slide over each other. Nevertheless, we feel that these benefits of the original method were outweighed by the ability to manipulate the MT1 head in all planes in order to obtain an optimal correction. Since the two fragments were eventually fixated by two cannulated screws, the shearing and rotational movements between the two fragments were eliminated.
This study had several limitations. Its retrospective nature prevented prospective patient randomization and allocation into three groups. We used standing x-ray radiographs for sesamoid evaluation, although standing CT scans could have better demonstrated the exact sesamoid location.[17] In our hospital this is the common practice for these patients and, therefore, this was the imaging modality that was available for us in this retrospective series. Because this was a solely radiographic study, we did not present the clinical outcomes or union rates of our patients. Since the clinical follow-up is of great interest, we are planning a future study in which these data will be presented in detail.
In conclusion, the “straight” osteotomy modification of the MICA procedure allowed us to reduce the HV deformity in all planes, and was the only method by which we were able to reduce the sesamoid bones into their normal position.