A durable solution for challenging multidrug-resistant bone infections: a retrospective study on long-term efficacy of the flow-through fibula osteocutaneous flap in limb reconstruction

BACKGROUND: Infectious bone and soft tissue defects caused by multidrug-resistant bacteria (MDRB) represent infrequent yet challenging medical conditions. Vascularized fibular grafting constitutes a crucial treatment modality in limb reconstruction procedures, offering improved recovery by supplying nutrients and structural support, particularly in large defects and compromised vascularity. The present study assessed the long-term outcomes of flow-through fibula osteocutaneous flaps for reconstructing multidrug-resistant infected bone and soft tissue defects. METHODS: Between January 2015 and January 2019, 39 patients with bone and soft tissue defects of the lower leg secondary to multidrug-resistant osteomyelitis were enrolled in this study. The study cohort comprised 23 male and 16 female participants, with a mean age of 45.33 ± 10.93 years. All limbs underwent multiple debridement procedures and were subsequently reconstructed using a flow-through fibula osteocutaneous flap combined with an external locking plate. Clinical and radiological outcomes, including flap survival, bone graft bridging, nonunion, infection recurrence, re-fracture and tibialization of the fibula, were evaluated and recorded over a minimum follow-up period of 5 years (ranging from 5 to 10 years). At the final follow-up, limb function was assessed using the Lower Extremity Functional Scale (LEFS). RESULTS: All the flow-through fibula osteocutaneous flaps survived well. The flow-through flap components measured a mean length of 11.72 ± 2.84 cm (95% CI, 10.83-12.61 cm) and a mean width of 5.69 ± 1.22 cm (95% CI, 5.29-6.09 cm). The median length of the fibula component was 8 cm (IQR: 7-11; 95% CI: 7.0-9.0 cm). Three flaps experienced venous crisis within 48 h postoperatively and ultimately survived following timely exploration, thrombectomy, and venous anastomosis. On the fourth postoperative day, two cases of the flap exhibited venous congestion accompanied by edema, which returned to normal after dressing change. The median length of hospital stay was 17 days (IQR, 16-19; 95% CI, 16.0-18.0 days). Bone graft bridging to the tibia was achieved in all patients, with a mean time of 4.23 ± 0.99 months (95%CI, 3.91-4.55 months). During the 5- to 10-year follow-up period, 32 of the 39 fibular grafts (82.05%) achieved tibialization. Although the remaining 7 grafts (17.95%) had not fully undergone tibialization, they exhibited a progressive trend toward increased thickness. No signs of infection recurrence or refracture were detected. At the final follow-up, all patients were able to walk normally, with a mean Lower Extremity Functional Scale (LEFS) score of 74.26 ± 2.04 (95%CI, 70.14-78.37). CONCLUSION: The flow-through fibula osteocutaneous flap may represent a viable reconstructive option for selected patients with multidrug-resistant infectious bone and soft tissue defects, showing acceptable osseointegration and a low incidence of infection recurrence in this small single-center series. These preliminary observations require validation in larger prospective cohorts.