Reversed Gracilis Pedicle Flap for Coverage of a Total Knee Prosthesis

Background: Poor wound-healing and skin necrosis are potentially devastating complications after total knee arthroplasty. Primary soft-tissue coverage with a medial or lateral gastrocnemius transposition flap is typically the first choice for reconstruction. The aim of this study was to evaluate the use of a distally based secondary-pedicle flap of the gracilis muscle for reconstruction of a soft-tissue defect.

Methods: The characteristics of the distally based (secondary) pedicles of the gracilis muscle were studied with use of dissection (ten cadavers) and computed tomographic angiograms (fifty patients). On the basis of the anatomical features, an extended reversed gracilis flap based on the secondary pedicles was used in three patients with severe soft-tissue complications of total knee arthroplasty.

Results: The mean number of secondary pedicles was 1.8 (range, one to four). The pedicles originated from the superficial femoral or popliteal artery. The most proximal pedicle was often the largest (mean caliber, 2.0 mm), and its point of entry into the gracilis muscle was an average (and standard deviation) of 21 +/- 3.6 cm (range, 16 to 28 cm) from the ischiopubic branch. A significant positive association (p = 0.001; r(2) = 0.49) was found between the caliber of the proximal secondary pedicle and the number of other secondary pedicles. In all three patients, the adequate caliber of the secondary pedicles (as shown on preoperative computed tomographic angiograms) and good muscle vascularization confirmed the utility of the gracilis as a distally based pedicle flap.

Conclusions: For the treatment of large soft-tissue defects of the patella or the proximal part of the knee, or for soft-tissue reconstruction over an exposed total knee prosthesis, the reversed gracilis pedicle flap may be an alternative to, or may be integrated with, a lateral or medial gastrocnemius flap.