Editorial Commentary: Caveat Flexor-To Release or Not to Release the Iliopsoas, That Is the Question.

In nonarthritic patients with femoroacetabular impingement syndrome, borderline dysplasia, and symptomatic iliopsoas snapping, arthroscopic iliopsoas fractional lengthening carries a significant risk of postarthroscopic instability. The iliopsoas is a dynamic stabilizer of the anterior hip. Thus, although statistically significant and clinically important improvements in hip function have the potential to be achieved with iliopsoas fractional lengthening, surgeons must be supremely confident in their ability to perform a secure capsular plication, labral preservation (not debridement), comprehensive cam correction, avoidance of intra-abdominal fluid extravasation, release of all iliopsoas tendon bands (if bifid or trifid), and ensure that femoral version is normal or low, neck-shaft angle is not excessively valgus, the dysplasia magnitude is no more than mild, and that there is no excessive soft tissue hypermobility. If these goals can be met, then excellent outcomes can be achieved. If not, then an iliopsoas fractional lengthening should not be performed.