Reconstruction of the Foot and Ankle Using Pedicled or Free Flaps: Perioperative Flap Survival Analysis

<div><p>Objective</p><p>The purpose of this study is to determine the correlation between non-technical risk factors and the perioperative flap survival rate and to evaluate the choice of skin flap for the reconstruction of foot and ankle.</p><p>Methods</p><p>This was a clinical retrospective study. Nine variables were identified. The Kaplan-Meier method coupled with a log-rank test and a Cox regression model was used to predict the risk factors that influence the perioperative flap survival rate. The relationship between postoperative wound infection and risk factors was also analyzed using a logistic regression model.</p><p>Results</p><p>The overall flap survival rate was 85.42%. The necrosis rates of free flaps and pedicled flaps were 5.26% and 20.69%, respectively. According to the Cox regression model, flap type (hazard ratio [HR] = 2.592; 95% confidence interval [CI] (1.606, 4.184); P < 0.001) and postoperative wound infection (HR = 0.266; 95% CI (0.134, 0.529); P < 0.001) were found to be statistically significant risk factors associated with flap necrosis. Based on the logistic regression model, preoperative wound bed inflammation (odds ratio [OR] = 11.371,95% CI (3.117, 41.478), P < 0.001) was a statistically significant risk factor for postoperative wound infection.</p><p>Conclusion</p><p>Flap type and postoperative wound infection were both independent risk factors influencing the flap survival rate in the foot and ankle. However, postoperative wound infection was a risk factor for the pedicled flap but not for the free flap. Microvascular anastomosis is a major cause of free flap necrosis. To reconstruct complex or wide soft tissue defects of the foot or ankle, free flaps are safer and more reliable than pedicled flaps and should thus be the primary choice.</p></div

Overall survival.

<p>The outcomes of the univariate analysis of risk factors influencing the perioperative flap survival rate. The univariate analysis was performed using the Kaplan-Meier method coupled with a log-rank test.</p

Patient characteristics

<p>Patient characteristics</p

The outcome of reconstruction of the foot and ankle in trauma patients in different periods

<p>The outcome of reconstruction of the foot and ankle in trauma patients in different periods</p

A 49-year-old male patient suffered from a mutilating forefoot injury, and the forefoot was reconstructed using the contralateral free plantar medial flap.

<p>a, Mutilating forefoot injury; b, after forefoot debridement; c and d, design and harvesting of free medial plantar flap; e and f, PN of the flap on the sixth postoperative day.</p

Multivariate Cox model results for predictive factors of free flap (n = 55) necrosis

<p>Multivariate Cox model results for predictive factors of free flap (n = 55) necrosis</p

The results of the 144 skin flaps

<p>The results of the 144 skin flaps</p

The eight subunits (I-VIII) within three regions (forefoot, midfoot, and hindfoot and ankle) of the foot and ankle.

<p>The eight subunits (I-VIII) within three regions (forefoot, midfoot, and hindfoot and ankle) of the foot and ankle.</p

Multivariate Cox model results for predictive factors of pedicled flap (n = 87) necrosis

<p>Multivariate Cox model results for predictive factors of pedicled flap (n = 87) necrosis</p

ELISA assays of IFN-γ, IL-17 and IL-4 in serum.

<p>Sera from collected blood at each time point (1, 3, 6, 11, 16, and 30 days) from xenotransplanted and sham control mice were used for ELISA analysis. Sera IFN-γ and IL-17 levels in the xenograft group were significantly higher than those in the serum in the control group (p<0.05) at day 1, day 3 and day 6, and decreased to control levels by day 11. There is no significant difference of IL-4 levels between recipients and control group. *, p<0.05; **, p<0.01; *** p<0.001. (We performed this experiment twice).</p