Predicting Union, Osteomyelitis, and Amputation Outcomes of Gustilo IIIC Open Tibial Fractures: A Retrospective Study

Abstract

Objective: Open tibial fractures are frequently encountered in high-energy traumas and can result in significant complications such as nonunion, osteomyelitis, and even amputation. Among open tibial fractures, Gustilo type IIIC cases are particularly challenging due to the concomitant occurrence of neurovascular injuries and soft tissue defects. This study aimed to assess factors that affect union time and complications in Gustilo IIIC tibial fractures.

Methods: Patients who presented at our center with IIIC open tibial fractures from January 2000 to October 2020 were eligible for this retrospective analysis. Patient demographics, fracture characteristics, and the timing, number, and type of surgical intervention were documented. Outcomes of interest included union time, occurrence of osteomyelitis, and amputation. We performed univariate analyses including chi-squared test, Fischer's exact test, analysis of variance, and Kruskal-Wallis test based on the normality of the data and multivariate analyses including Cox proportional hazards model and logistic regression analyses.

Results: Fifty-eight patients were enrolled and grouped by fracture healing time; eight had timely union (13.8%); 27 had late union (46.6%); eight had delayed union (13.8%); three had nonunion (5.2%); and 12 underwent amputation (20.7%). Nine fractures (15.5%) were complicated by osteomyelitis. Union time was prolonged in cases of triple arterial injury, distal third fractures, multiple trauma with injury severity score (ISS) ≥ 16 points, and increased bone defect length. Additionally, a bone gap >50 mm, diabetes mellitus, low body mass index, and triple arterial injury in the lower leg were significant risk factors for amputation. A time from injury to definitive soft tissue coverage of more than 22 days was the major risk factor for osteomyelitis. A scoring system to predict union time was devised and the predicted probability of union within 2 years was stratified based on this score.

Conclusion: IIIC tibial fractures involving the distal third of the tibia, fractures with bone defects, triple arterial injury, and multiple trauma with ISS ≥16 points demonstrated delayed union, and an effective prediction system for union time was introduced in this study. Early soft tissue coverage can reduce the risk of osteomyelitis. Finally, diabetes and severe bone and soft tissue defects pose a higher risk of amputation.

Keywords: Gustilo IIIC tibial fractures; Injury severity score; Nonunion; Osteomyelitis; Union time.

FIGURE 1

Patient enrollment process in the present study. Note: *The excluded patients were eight individuals with insufficient data, one patient with refracture due to trauma during the follow‐up period, one patient transferred from another institution after initial management, and two patients with malleolar fractures.

FIGURE 2

Radiographic images of pre‐ and post‐operation and united IIIC fractures. (A) A preoperative image showing a patient with extensive bony and soft tissue defect who temporarily received an external skeletal fixator. (B) The patient in (A) subsequently received contralateral free fibular flaps for the simultaneous reconstruction of bony and soft tissue defects. The bony component of the flap was fixed with multiple locking plates. (C) Two years after reconstruction for the patient in (A). The fracture site showed a bridging callus and a smooth soft tissue contour. (D) A preoperative image of another patient with a shorter bony defect compared to (A). (E) The patient in (D) received intramedullary nail fixation and multiple debridements and sequestrectomies, awaiting subsequent reconstruction. (F) The patient then underwent the two‐staged Masquelet technique with a satisfactory postoperative bridging callus in the fracture site 1 year after surgery.

FIGURE 3

Predicted probability of union within 730 days for type IIIC tibial fractures and factors affecting probability of union. (A) Cox proportional hazards (PH) model of union time. Cox‐PH model comparing: fractures with and without triple arterial injury, fractures in the distal third against fractures in other locations, fractures with and without multiple trauma with Injury Severity Score (ISS) ≥ 16 points, and bone defect length; (B) Patient grouping according to the probability estimated by the Cox‐PH model. Using the present model, the cohort was divided into three groups according to the probability of union from low to high which is presented in a Kaplan–Meier plot. CI, confidence interval; HR, hazard ratio.

FIGURE 4

Logistic model predicting osteomyelitis occurrence. The logistic model of osteomyelitis where definitive tissue coverage is achieved in more or less than 22 days. CI, confidence interval.

FIGURE 5

Logistic model predicting amputation. The logistic model of amputation comparing: patients with and without diabetes mellitus (DM), a bone gap length of less or more than 50 mm, body mass index (BMI), and triple arterial injury. CI, confidence interval; OR, odds ratio; Q3, the third quartile data in bone defect length.