Bone-based versus soft-tissue free flaps in lower extremity reconstruction.

Background: Most lower extremity defects and minor bone defect wounds requiring a free flap are treatable with soft-tissue flaps, whereas large bone defect wounds are treated with bone-based flaps. This study aimed to compare bone-based and soft-tissue-free flaps in terms of operative procedures and postoperative complications, including long-term outcomes of lower extremity reconstruction.

Methods: This two-center retrospective cohort study collected data from all lower-extremity reconstructions with free flaps performed between March 2014 and February 2022; the level of evidence is considered to be therapeutic level III. We investigated the operative procedure and postoperative complications classified as being related to either bone-based or soft-tissue flaps. The data were further classified into the trauma and non-trauma groups and the long-term postoperative outcomes of patients who were followed up for ≥12 months were analyzed.

Results: A total of 122 free flaps were included: 29 bone-based flaps (1 scapular and 28 fibular flaps) and 93 soft-tissue flaps (22 muscle-based and 71 fasciocutaneous flaps). There was no significant difference in postoperative complications, including long-term outcomes, between the free flap types, regardless of etiology. Vein grafts were used more often for bone-based flaps than for soft-tissue flaps (20.7% vs. 7.5%; p = 0.045). The donor veins of bone-based flaps were more often anastomosed to superficial veins than were those of soft-tissue flaps (37.9% vs. 10.8%; p < 0.001).

Conclusions: Using bone-based free flaps resulted in no significant differences in postoperative complications, including long-term outcomes, despite involving more complicated operative procedures than soft-tissue flaps. Thus, the use of vein grafts and anastomosis to the superficial venous system of the vascularized fibula graft may help avoid flap-related complications in bone-based free flaps.