Soft-tissue Coverage for Complex Knee Defects: The Role of Microsurgery in Optimizing Functional Limb Salvage

Soft-tissue defects of the knee pose unique reconstructive challenges, and inadequate coverage can have devastating sequelae, including amputation. The purpose of this study is to evaluate the indications and role of microsurgical free flaps, in comparison with pedicled gastrocnemius flaps, for soft-tissue reconstruction of the knee.

Patients undergoing soft-tissue reconstruction of knee defects from 2018 to 2024 at a tertiary care center were analyzed. Patient characteristics and outcomes were compared for reconstructions using free flaps versus gastrocnemius flaps. The primary outcome was limb salvage with ambulation. Secondary outcomes included patient-reported outcomes and complications.

A total of 43 patients comprised the study population: 25 with pedicled gastrocnemius flap and 18 with free flap reconstructions. Limb salvage was achieved in 88.9% of patients with free flaps and 84.0% of patients with pedicled flaps (P = 0.67). Functional outcomes were similar between free and pedicled flaps (mean Lower Extremity Functional Scale scores of 51.2 ± 13.6 versus 47.5 ± 12.8, P = 0.40). Defect size was larger in the microsurgical versus pedicled cohort (88 ± 35 versus 65 ± 20 cm², P = 0.019). Reoperations/secondary procedures were high in both cohorts: 55.6% of patients with free flaps versus 60.0% of patients with pedicled flaps (P = 0.62).

Although pedicled flaps remain a mainstay of treatment algorithms, microsurgical reconstruction offers a safe and versatile option for achieving functional limb salvage in select large, complex knee defects. We advocate for a patient-centered and defect-specific approach to soft-tissue reconstruction of the knee.