Functional outcomes of traumatic lower extremity reconstruction

Abstract

Background

Lower extremity trauma accounts for over 300,000 injuries annually. While soft tissue transfer is a well-accepted practice for open fracture coverage, functional outcomes remain unclear.

Hypothesis

This study investigates functional outcomes following soft tissue reconstruction for open tibial fractures.

Materials and methods

A retrospective review of a prospectively maintained database of open tibia fractures requiring soft tissue reconstruction was performed at an urban level 1 trauma center between October 2013 and March 2015.

Outcomes

were evaluated using Pearson’s chi square test with significant p value < 0.05.

Results

In 30 patients, fractures were graded Gustilo-Anderson type I (3.3%), 30% type II, 3.3% type IIIa, 53.3% type IIIb, and 10% type IIIc. Fixation was 56.7% plate and screw, 20% intramedullary nail, and 16.7% external fixator. Definitive closure was achieved in 43.3% through local rotational flap (38.5% gastrocnemius, 61.5% soleus), and in 56.7% by free tissue transfer (29.4% latissimus, 23.5% rectus, 17.6% ALT, 17.6% gracilis). In 10 patients, 70% returned to full ambulation, 30% required an assistance device, and 50% achieved union in 6 months. Local flap use was predictive of ambulation at discharge.

Discussion

Following lower extremity fracture, 70% of patients returned to pre-injury function. Use of a local tissue flap was associated with early ambulation.

1. Introduction

The lower extremity is the most frequently injured body region with over 300,000 injuries annually, accounting for nearly 37% of all reported injuries¹. The tibia is the most common open long bone fracture, with 24% of tibial fractures classified as open². Open fractures confer a greater risk of complications including deep tissue infection and osteomyelitis, compartment syndrome, aseptic nonunion, venous thromboembolism, and long term morbidity associated pain and loss of function³. The requirement of ambulation for most daily activities creates a significant morbidity associated with lower extremity injury. With an average recovery time of four months for an uncomplicated, closed tibia fracture, even routine care of lower extremity fractures results in significant costs in time and expenses⁴.

Extensive soft tissue damage or tissue loss associated with open fractures requires soft tissue reconstruction. Wounds can be closed acutely or delayed to follow open reduction and internal fixation (ORIF) using locoregional or microvascular free tissue transfer. Early wound closure with vascularized tissue has been shown to decrease infection, bone-healing time, length of hospital stay, and total number of operations^{5, 6, 7, 8}. Definitive soft tissue reconstruction is therefore vital to the salvage of traumatized lower extremities and reduction in complications.

Soft tissue reconstruction outcomes are usually determined by definitive closure or successful limb salvage. It has been reported that delayed revascularization, blunt trauma, high velocity penetrating trauma, and Gustilo-Anderson (GA) grade III injuries are associated with higher rates of amputation⁹. While multiple reports have described the success of soft tissue reconstruction in open lower extremity fractures, factors contributing to the functional outcomes of ambulation, use of assistance devices, and return to work or sports after vascularized tissue transfer remain less clear.

Evaluating soft tissue reconstruction solely for operative outcomes gives an incomplete evaluation of the success of the reconstruction. Ultimately the goal is to return patients to their pre-injury level of function. This study investigates the functional outcomes of patients following open tibia fracture requiring definitive wound closure by local or free microvascular tissue transfer, focusing on the primary goal of identifying pre and perioperative determinants of ambulatory status.

2. Methods

A retrospective review of a prospectively maintained database of patients with open tibial fractures requiring definitive soft tissue coverage by the Plastic and Reconstructive Surgery service in a metropolitan level 1 trauma center between October 2013 and March 2015 was performed. Inclusion criteria for study patients were: (1) open tibia fracture; (2) required definitive soft tissue coverage; (3) operated on by the Plastic and Reconstructive Surgery service at LAC + USC; (4) available follow-up records of ambulation and functional use of the lower extremity. Minors, patients that refused treatment, were transferred to another hospital prior to soft tissue reconstruction, or died prior to soft tissue reconstruction were excluded from the study. A flow chart of included patients can be seen in Fig. 1. Patient characteristics, perioperative data, and patient and physician reported functional outcomes were recorded in accordance with the LAC + USC Medical Center institutional review board.

Fig. 1.

Patient Flow Chart.

3. Preoperative characteristics

Patient demographics included age, gender, height, weight, and BMI. We compiled pre-injury level of function, comorbidities, other injuries, substance use, medications, ASA class, and injury characteristics including mechanism, fracture type, wound location, antibiotic use, and time to initial debridement. GA classification was determined through physician documentation or operative dictations.

3.1. Perioperative data

Perioperative data collection included all procedures, medications, flap characteristics, post-flap treatment protocols, labs and vitals, and complications.

3.2. Functional outcomes

Functional outcomes were recorded based on physician evaluations and patient reported outcomes. Clinical bony union and time to union were recorded. Functional outcomes were defined as ambulatory (walking unassisted or full weight bearing), use of an assistance device (walker, crutches, or cane), non-ambulatory (use of a wheelchair), or amputated, and were compared with pre-injury function. The earliest date of highest level of ambulation was recorded.

3.3. Statistical analysis

Statistical analysis was performed using Microsoft Excel (2010) software (Microsoft Corp., Redmond, WA). Outcomes were evaluated using Pearson’s chi square test with a p-value < 0.05 considered significant.

4. Results

4.1. Patient characteristics

Thirty patients met study inclusion criteria, of which 86.7% were male with average age 33.9 ± 16 years (Table 1). The average BMI was 26.1 ± 5.6 kg/m² and 46.7% of patients were active smokers. Prior to injury, all patients ambulated without use of an assistance device. Injury characteristics are reported in Table 1. Of 30 subjects, GA grade prior to debridement was 1 (3.3%) type I, 9 (30%) type II, 1 (3.3%) type IIIa, 16 (53.3%) grade type IIIb, and 3 (10%) type IIIc. Definitive bone fixation was performed through plate and screw in 17 (56.7%), intramedullary nail in 6 (20%), or external fixator in 5 (16.7%), while 2 patients were lost to follow-up before fixation was achieved.

Table 1.

Patient Demographics and Injury Characteristics (n = 30).

Patient Demographics
Gender (male: female)	26 (86.7%): 4 (13.3%)
Current smoker	14 (46.7%)
Average age	33.9 ± 16 years old (range 10–81)
Average BMI	26.1 ± 5.6 kg/m2
Average follow-up	4 ± 3.89 months (range 5–476 days)

Gustilo-Anderson Grade
I	1
II	9
IIIa	1
IIIb	16
IIIc	3

Definitive Fixation
Plate and screw	17 (56.7%)
Intramedullary nail	6 (20%)
External fixator	5 (16.7%)

Flap
Local	13 (43.3%) through local rotational (38.5% gastrocnemius, 61.5% soleus)
Free	17 (56.7%) by free tissue transfer (29.4% latissimus dorsi, 23.5% rectus abdominis, 17.6% anterolateral thigh, 17.6% gracilis, 11.9% other)

Definitive closure was achieved in 13 (43.3%) through local rotational flap (38.5% gastrocnemius, 61.5% soleus), and in 17 (56.7%) by free tissue transfer (29.4% latissimus dorsi, 23.5% rectus abdominis, 17.6% anterolateral thigh, 17.6% gracilis, 11.9% other). Average time to definitive closure from incident date was 27 ± 32.5 days (range 2-125 days). Five patients (16.7%) required fasciotomies prior to soft tissue reconstruction. No flaps were lost. Three patients (10%) had wound infections prior to soft tissue reconstruction, which was reduced to one patient (3.3%) with wound infection after soft tissue reconstruction. Average estimate blood loss was 570 ± 1231 mL and 9 (30%) transfusions were performed. The average time to discharge after soft tissue reconstruction was 14 days. The average follow-up time was 4 ± 3.89 months with a range of 5 − 476 days.

4.2. Union

Of the 10 patients with 6 or more months of follow-up, 5 (50%) patients achieved union or delayed union. Average time to union was 216 days (range 84-441 days) as seen in Table 2. Two (20%) patients were smokers, of which one returned to full weight bearing ambulation while the other required use of an assistance device. Current smokers trended to non-union by Pearson’s chi square (p = 0.057), but the study was underpowered to achieve significance. Age, gender, and flap type did not correlate with non-union. BMI greater than 30 kg/m² was not significantly related to rate of union (p = 0.69).

Table 2.

Bone Union in Patients with Greater than 6 Months Follow-Up (n = 10).

Bony Union
Union	5 (50%)
Time to Union	216 ± 153 days

No association with non-union
Smoking	p = 0.057
BMI > 30 kg/m2	p = 0.69

4.3. Ambulation

Of the 30 patients included in the study, GA grade I or II injury, absence of nerve or arterial injury, and tibial union were associated with full ambulation (p < 0.05) (Table 3). Neither smoking nor extremity dangling prior to discharge was associated with ambulatory status (p = 0.76, 0.78, respectively). Age, gender, BMI, and flap type showed no correlation with ambulation. However, use of a local flap was predictive of full-weight bearing ambulation or ambulation with an assistive device at discharge (p < 0.05).

Table 3.

Ambulation Outcomes.

Associated with full weight-bearing ambulation at last follow-up
Union	p < 0.05
Lack of nerve injury	p < 0.05
Lack of artery injury	p < 0.05
Gustilo-Anderson Grade I or II	p < 0.05

Associated with full weight-bearing or assistive device ambulation at discharge
Local flap	p < 0.05

No association (p > 0.05)
Smoking with non-ambulation	p = 0.76
Dangling before DC with ambulation	p = 0.78
Age	p = 0.83
Gender	p = 1
BMI	p = 1

Of 10 patients with a minimum of 6 months follow up, all patients were ambulatory by 7 months follow up. Seven (70%) patients were able to return to their pre-injury level of function and 3 (30%) required use of an assistance device. Eight patients with physical therapy records participated in an average of 5.9 ± 3.2 months of therapy (range 1.8–9 months).

5. Discussion

Results of this study demonstrate a high rate of return to previous level of function with full weight bearing ambulation by seven months in patients with open tibial fractures requiring soft tissue reconstruction. While long term follow-up was low (66%) in the county healthcare system, use of a local flap for definitive wound closure was associated with early ambulation at the time of discharge. Union and less severe injuries (lack of nerve or artery injury and GA grade I or II) were associated with return to ambulation. Smoking and early dangling protocols require larger sample sizes to power the study to detect significance.

In the study done by Godina, early reconstruction (<3 days), delayed reconstruction (3 days–3 months), and late reconstruction (>3 months) showed infection rates of 1.5%, 17.5%, and 6%, respectively. We found low rates of infection (3.3%) as compared with Godina’s study despite an average of 27 ± 32.5 days to reconstruction with a range of 2-125 days. We attribute the lower rates to advances in the understanding and application of post trauma care, antibiotic use, time to wound debridement, local wound care, understanding of biofilms, and use of intramedullary fixation devices that have occurred over the past 30 years since his landmark paper.

Interestingly, over 1/3rd of patients in this study required soft tissue reconstruction for Gustilo-Anderson Grade I-IIIa injuries, which are traditionally wounds that may be closed primarily. Indications for surgery in this population ranged from wound coverage after extensive debridement, infectious complication, and repair of fasciotomies after compartment syndrome. This data indicates that underappreciation of soft tissue injury, misclassification of Gustilo-Anderson grade, and resulting under-debridement remains a common problem in the treatment of open tibial fractures.

Socioeconomic factors unique to our population lead to systemically low patient follow up in the county healthcare system. As a result, long term follow up and assessment of functional status is limited. Because of the retrospective nature of our investigation, we were unable to collect standardized functional outcomes using validated tools including LEFS or SF-36. Future investigations should include comparison and application of these standardized functional assessment tools to a prospective cohort. Additionally, our limited follow up may have led to under or overstating of associations. For example, ambulation rates may in fact be higher than we report since there is likely a tendency for patients with complications and device dependence to return for follow up, while fully ambulatory patients without complications would be more likely to cancel follow up appointments. Future studies might utilize telephone follow up in an effort to apply validated functional outcomes measures and increase study population and power.

In patients requiring soft tissue coverage of an open tibia fracture, 70% patients were able to return to their previous level of function by 7 months postop and the remaining 30% were ambulatory with an assistance device. Gustilo-Anderson grade I and II injuries and fracture union correlated with return of unassisted ambulation. Currently reported functional outcomes data after soft tissue reconstruction of open tibial fractures is limited and merits further study.

6. Conclusion

In patients requiring soft tissue coverage of an open tibia fracture, a large majority resume unassisted ambulation by 7 months postop. Fractures with lower Gustilo-Anderson grade and fracture union were more likely to result in unassisted ambulation, however futures studies are warranted to further characterize functional outcomes in lower extremity trauma.

Conflict of interest

None.