NONOPERATIVE ESTIMATION OF THE SOLEUS MUSCULOTENDINOUS JUNCTION USINGMAGNETIC-RESONANCE-IMAGING

Although it is recognized as the muscle flap of choice for middle-thir d defects of the lower limb, the capability for even more distal trans position of the soleus muscle remains controversial. Such reach depend s directly on the site of insertion of the muscle and previously has n ot been assessed convincingly without surgical intervention. Magnetic resonance imaging (MRI) may be a noninvasive alternative for determini ng the distal extent of the musculotendinous junction of the soleus mu scle. In our last four patients, preoperative MRI scans were obtained prior to an elective soleus muscle transfer. The distance from the ank le joint to the most distal site of the soleus insertion was measured on the MRI scan and compared with the actual intraoperative measuremen t, which had a significant correlation (r = 0.98, p = 0.019). A retros pective review of 42 other sagittal ankle MRI scans predicted the mean of the distance to be 1.92 +/- 1.23 cm (range -0.4 to 4.5 cm), compar ed with gross anatomic dissections in 30 unrelated fresh cadavers, whe re this was 4.06 +/- 3.11 cm (range -0.7 to 12.5 cm). These additional data are pertinent because they reinforce recognition of the great va riation in soleus anatomy, which would limit clinical applications for the distal third of the leg only for those individuals with very dist al insertions. The MRI scan can reliably identify the soleus muscle an d provides a nonoperative method for evaluation of potential feasibili ty for its use as a local muscle flap for distal lower extremity defec ts.