Rotational flap versus long plantar flap for transmetatarsal amputation closure following revascularization

Abstract

Objective

The integrity of the plantar flap is important for transmetatarsal amputation (TMA) classic closure. However, in ischemic wounds, the plantar flap can be compromised, making the TMA coverage difficult. The aim of this study was to compare the outcomes of rotational vs long plantar flaps for transmetatarsal amputation closure in patients with dysvascular partial foot amputations.

Methods

We conducted an observational study including revascularized patients with established forefoot gangrene who required TMA. The coverage was performed by classical long plantar flap or rotational flap due to the lack of adequate plantar skin. Seventeen patients were included in the study. TMA was performed after lower limb revascularization in all cases. We compared the wound healing and functional outcomes of the two groups (rotational vs long plantar flap).

Results

The mean age of the sample was 66.5 years (±8.3 years). Eight cases (47%) had open surgical bypass, and nine (53%) had endovascular procedures. Eight cases of rotational flaps (7 medial plantar rotational flaps) and nine classical long plantar flaps were analyzed. Our results demonstrated an overall healing rate of 77% in the sample. There was no significant difference between the surgical techniques evaluated. The healing percentage for the rotational flap group was 75% (6 cases) and 78% (7 cases) for the classical long plantar flap closure (P = .6).

Conclusions

Rotational flap provides a feasible alternative to classical long plantar flap for TMA coverage, showing a satisfactory healing rate for dysvascular foot following revascularization.

Diabetes mellitus (DM) and peripheral artery disease (PAD) are some of the major contributors to severe wounds and foot amputations in the world. It is estimated that 80% of lower limb amputations are related to DM complications.^1,2 DM-related limb complications affect over 130 million people worldwide, resulting in more than 6.8 million amputees.²

Over 70 years ago, transmetatarsal amputation (TMA) was proposed as an alternative for delimited gangrene of the toes, offering both immediate and delayed closure options.³ In the 1940s, McKittrick et al observed that TMA amputations had poor outcomes in patients with a nonviable plantar flap.⁴ Over the years, advancements in revascularization have made TMA a reliable option for maintaining foot length and function in many cases, effectively preserving ambulation with satisfactory results.⁴ A systematic review found a reoperation rate of 24.43% after transmetatarsal amputations and an amputation rate of 28.37%, and the major amputation rate was found to be 30.16%.⁵ Despite the risk of reamputation, TMA provides a greater chance of rehabilitation and independent ambulation, along with lower morbidity and mortality rates, compared with major amputations.⁶ DM, PAD, infection, and other comorbidities have been previously reported as factors for impaired TMA wound healing.7, 8, 9, 10 However, it remains difficult to predict which patients are less likely to have TMA healing.^11,12

It has been observed that TMA wound closure can lead to greater probability of stump healing.¹⁰ Classical surgery technique for TMA closure emphasizes the importance of the long plantar flap integrity.^3,13 However, in severe ischemic foot wounds, compromised plantar tissue can make classical TMA closure very challenging. In these situations, other closure options have been proposed, including a rotational flap.^14,15 Indeed, medial and lateral plantar rotational flaps have already been described for partial foot and TMA coverage in diabetic patients with complex neuropathic ulcers, achieving a successful outcome.^14,15

Given the need for an alternative in situations of extensive gangrene and compromised plantar tissue, the aim of this study was to compare the outcomes of rotational and long plantar flaps in patients with established forefoot gangrene following revascularization, to assess if the rotational approach is a viable option for TMA coverage.

Material and methods

Patients

A single-center, observational, cross-sectional, retrospective, and comparative study was conducted at University Hospital. Data collection from medical records and clinical registers were performed at a tertiary care reference center. The present study included consecutive hospitalized patients treated for ischemic foot wounds requiring TMA covering by a rotational flap or long plantar flap, between August 2017 and May 2019. Only patients with ischemic established forefoot gangrene requiring TMA were included. All patients had chronic limb-threatening ischemia (CLTI) and had undergone lower extremity revascularization before TMA. All patients were classified as Rutherford category 5 (Rutherford’s chronic limb ischemia classification). Patients were excluded if they did not have ischemic forefoot gangrene that required TMA. In total, 17 patients were included in the study: eight cases in the group of rotational flap coverage and nine patients who underwent a classical long plantar flap for TMA closure. This study protocol was approved by the Research Ethics Committee of the Hospital, approval numbers 39514020.6.0000.0049/4.439.159.

Methods

The study investigated demographic characteristics of the patients (age and sex), comorbidities, DM, systemic arterial hypertension, PAD, chronic kidney disease, and white blood cell count (WBC), comparing two different techniques (rotational flap or long plantar flap) for TMA wound closure. Patients with DM, systemic arterial hypertension, and chronic kidney disease had a previous diagnosis and were undergoing treatment at the same hospital. All patients had a diagnosis of PAD and an absence of both foot pulses (posterior tibial and pedal pulses), confirmed by digital subtraction angiography or computed tomography angiography prior to revascularization. Demographic and clinical characteristics of the sample were studied, considering the two groups according to the type of TMA coverage (rotational flap or long plantar flap). Revascularization was performed for CLTI in all subjects, individualized according to angiographic and clinical characteristics of patients, employing open bypass surgery or endovascular procedures. Hyperbaric oxygen therapy was not used. Healing rate and functional outcomes of the two types of TMA closure were compared regarding limb salvage and wound healing. The average follow-up duration was 420 ± 551 days, ranging from 30 to 1670 days.

Statistical analysis

Statistical analysis was conducted using Epi Info version 7.2.2.6. Continuous data were described with descriptive statistics (mean, standard deviation), whereas categorical variables were characterized by frequency, proportions, or percentages. Comparative analysis of categorical variables was performed using the Fisher exact test. Continuous variables were described by their means and standard deviations, and comparative analysis was conducted using analysis of variance. Statistical significance was assumed at P values less than .05.

Results

Clinical and demographic characteristics of the sample

The study included 17 patients who underwent a closed TMA following revascularization. The mean age of the patients was 66.5 years (±8.3 years). Ten of the patients (59%) were women, and 12 of them (71%) were diabetic. All patients underwent amputations for ischemic necrosis of the forefoot. Open surgical bypass procedure was carried out in eight cases (47%), and endovascular revascularization was done in nine cases (53%) for CLTI treatment. Considering the three-vessel lower extremity runoff (peroneal, anterior, and posterior tibial arteries), eight limbs (47%) had one vessel, eight limbs (47%) had two vessels, and only one limb (6%) had three arteries (average number of infrapopliteal runoff vessels of 1.6 ± 0.6). Rotational or classical plantar TMA closure was performed four to fifteen days after open surgical or endovascular revascularization. The average duration of forefoot wounds was 106 days (±56 days). Among the nine patients who had a TMA closure by long plantar flap, the average age was 67.9 years (±10.2 years). Six of them (67%) were diabetic, and eight (89%) were hypertensive. All nine patients were revascularized before TMA, four (44%) underwent open surgical bypass (4 femoropopliteal bypass surgery), and five had endovascular treatment (1 common iliac transluminal angioplasty and 4 superficial femoral artery balloon angioplasty). Medial or lateral rotational flaps were performed for TMA coverage in eight patients. Their average age was 64.9 years (±5.6 years), with six (75%) being diabetic and five (63%) hypertensive. In this group, four patients (50%) underwent open surgical bypass (3 femoropopliteal bypass surgery and 1 aortofemoral bypass), and four had endovascular revascularization (3 superficial femoral artery balloon angioplasty, with or without stenting, and one posterior tibial artery balloon angioplasty). The proportions of smokers were higher for the rotational flap group (67% vs 25%; P = .1). In Table I, characteristics of the study population and a comparative analysis of the cases are presented in detail.

Table I.

Comparison of sample characteristics and outcomes according to the two different types of transmetatarsal amputation (TMA) closure (long plantar flap vs rotational flap) (n = 17)

Characteristics	Total	Long plantar flap	Rotational flap	P valuea
Female gender	10 (59)	6 (67)	4 (50)	.4
Age, years	66.5 (±8.3)	67.9 (±10.2)	64.9 (±5.6)	.5
Diabetes	12 (71)	6 (67)	6 (75)	.6
WBC, /mL	12,455 (±4936)	12,042 (±4335)	13,005 (±6033)	.7
Heart disease	1 (6)	0 (0)	1 (13)	.5
Hypertension	13 (76)	8 (89)	5 (63)	.2
Smoker	9 (53)	2 (25)	6 (67)	.1
CKD	1 (6)	0 (0)	1 (13)	.5
Ankle-brachial index	0.73 (±0.1)	0.79 (±0.2)	0.7 (±0.1)	.4
Infrapopliteal runoff vessels	1.6 (±0.6)	1.8 (±0.7)	1.4 (±0.5)	.2
Revascularization procedure				.6
Open surgical bypass	8 (47)	4 (44)	4 (50)
Endovascular revascularization	9 (53)	5 (56)	4 (50)
Arterial segment (PAD)				.5
Aortoiliac	2 (12)	1 (11)	1 (12.5)
Femoropopliteal	14 (82)	8 (89)	6 (75)
Infrapopliteal	1 (6)	0 (0)	1 (12.5)
Wound healing (TMAa)/limb-salvage	13 (77)	7 (78)	6 (75)	.7

CKD, Chronic kidney disease; PAD, peripheral artery disease.

Data are presented as number (%) or mean (± standard deviation).

^aThe Fisher exact P value.

Characteristics and results of rotational flap closure for TMA

Regarding the eight patients with TMA stump closure by rotational flaps, seven of them (87.5%) had tissue viability of the medial flap (no hallux necrosis), despite compromised plantar tissue (Fig 1, Fig 2, Fig 3, Fig 4). The most frequent technique performed was a medial plantar rotational flap (Fig 1, Fig 2, Fig 3, Fig 4). In one patient with compromised great toe and a previous second toe amputation, a lateral rotational flap was performed for TMA coverage (Fig 5). The rotational flap technique for TMA closure has been described by Boffeli et al.^14,15 According to their technique, all non-viable tissue is removed, preserving skin and subcutaneous viable tissue flap for rotational technique. After removing necrotic tissue, TMA amputation was performed, followed by copious irrigation of the stump with 0.9% saline solution. A rotational flap was used for TMA coverage, with non-absorbable suture and wound closure as the final step. In the study sample, six patients (75%) experienced favorable outcomes after rotational flaps, with TMA healing and limb salvage (Fig 4). Following rotational flap surgery, two patients had TMA irreversible ischemic tissue loss necessitating a below-knee amputation. Limb salvage and good functional outcome, with functional ambulation, was achieved in six patients in whom the rotational flap healed. Table II provides information about the eight cases in which the rotational flap (medial or lateral) was performed.

Fig 1.

A, A 65-year-old female with extensive forefoot gangrene with plantar flap compromising (arrow); B, Aspect of the dorsal region of the foot; C, Medial plantar artery rotational flap with adequate arterial perfusion (arrow). D and E, Aspect of the transmetatarsal amputation closure with the medial plantar artery rotational flap.

Fig 2.

A and B, A 65-year-old male with extensive forefoot gangrene; C and D, Aspect after transmetatarsal amputation and closure with the medial plantar artery rotational flap; E and F, Aspect of the amputation 30 days after medial rotational flap with a small area of dehiscence with favorable outcome.

Fig 3.

A and B, A 68-year-old female with extensive forefoot gangrene with plantar flap compromising; C and D, Skin flap for making medial plantar lap with good perfusion; E and F, Aspect of the transmetatarsal amputation closure with the medial plantar rotational flap G and H, Ten days after the medial plantar rotational flap with a favorable long-term outcome.

Fig 4.

A, A 71-year-old male with extensive forefoot gangrene; B, Aspect of the transmetatarsal amputation (TMA) closure with the medial plantar rotational flap; C and D, Aspect of the medial plantar artery rotational flap coverage (1.4 years) with a favorable long-term outcome.

Fig 5.

A and B, A 63-year-old male with and hallux/first metatarsal gangrene and previous second toe amputation; C and D, Aspect after lateral plantar artery rotational flap for transmetatarsal amputation (TMA) closure with a favorable long-term outcome.

Table II.

Clinical outcomes among patients with medial (MPAA) and lateral plantar (LPAA) artery angiosome-based rotational flap transmetatarsal amputation (TMA) coverage (n = 8)

Age/ sex	PAD arterial segment	Comorbidities	Rotational flap	Revasculari Zation	Limb-salvage/	Wound healing	Duration of follow-up, days
71/M	Femoropopliteal	Diabetes, hypertension, smoker	MPAA	Femoral popliteal bypass	Yes	Yes	1670
70/F	Femoropopliteal	Diabetes, hypertension	MPAA	SFA angioplasty	No	–	–
65/M	Femoropopliteal	Smoker	MPAA	Femoral popliteal bypass	Yes	Yes	150
68/F	Femoropopliteal	Diabetes, hypertension	MPAA	SFA angioplasty	Yes	Yes	1185
65/F	Femoropopliteal	Diabetes, smoker	MPAA	Femoral popliteal bypass	Yes	Yes	30
63/M	Infrapopliteal	Diabetes, hypertension, smoker	LPAA	PTA angioplasy	Yes	Yes	1095
53/F	Femoropopliteal	Diabetes, hypertension, smoker	MPAA	SFA angioplasy	No	-	-
64/M	Aortoiliac	Smoker	MPAA	Aortofemoral bypass	Yes	Yes	30

F, female; M, male; PAD, peripheral artery disease; PTA, posterior tibial artery; SFA, superficial femoral artery.

Comparative results of two different TMA closure techniques (rotational flap vs classical long plantar flap)

In this sample, 17 patients were analyzed. In nine cases, a classical long plantar flap was performed for TMA coverage (Fig 6), and in eight, a rotational flap. In our study, 13 patients (77%) that underwent TMA closure had their wound healed, and 12 (71%) became ambulatory. A transtibial or below-knee amputation was required in four (23%) when nonviable flap was present, due to progressive ischemia. None of the patients had infections leading to TMA failure, and all of them received antibiotic therapy. Comparing outcomes between rotational flap (8 cases) and classical long plantar flap (9 cases), no significant differences were found in wound healing and limb salvage. In the classical long plantar flap group, seven cases (78%) healed after TMA closure, similar to the healing rate of six patients with rotational flap (75%). Long-term ambulatory function was found in six patients in whom the rotational flap healed. Among seven cases in which classical plantar coverage healed, six cases achieved long term ambulatory function, with one case not reaching this function due to comorbidities that significantly influenced functional outcomes.

Fig 6.

A and B, A 58-year-old female with forefoot gangrene requiring a reamputation with no plantar flap compromising; C-E, Aspect of the transmetatarsal amputation (TMA) with classical long plantar flap coverage with a favorable outcome.

Discussion

The results of this study demonstrate that a rotational flap can be a satisfactory option for TMA coverage in forefoot gangrene involving plantar tissue compromise. In our sample, which included only revascularized patients with CLTI, the rotational flap showed no significant difference in healing rate and limb salvage compared with the classical long plantar flap.

In the literature, the outcomes of rotational flap procedure for TMA coverage in two cases of neuropathic ulcers in diabetic patients have already been described.¹⁴ Boffeli and Waverly published four cases of rotational flaps for TMA and Lisfranc amputations in patients with compromised plantar tissue: medial plantar artery angiosome (MPAA) and lateral plantar artery angiosome (LPAA) rotational flaps.¹⁵ The authors employed their knowledge of angiosome anatomy to describe a medial or lateral plantar artery angiosome-based rotational flaps for covering forefoot soft tissue defects without TMA stump shortening.15, 16, 17 In the present study, the medial plantar rotational flap (MPAA) was the most common procedure due to tissue viability of the first toe. The probable reason for the MPAA predominance involves the angiosome concept and anatomical variations in hallux vascular supply, which can originate from three pathways: the dorsalis pedis artery, the lateral plantar artery, or the medial plantar artery.^15,17 Another possible explanation for this predominance is the presence of arterial anastomoses between adjacent angiosomes.15, 16, 17

TMA primary wound closure can be difficult when wounds are large or complex, or even may not be indicated in severe foot infection. An open guillotine TMA is also an option in severe infections and in cases of compromised plantar flap.¹³ In the literature, a retrospective study including 62 TMAs (57 patients) found a 73% healing rate after primary closure of TMA, and a 27% healing rate in cases where wound closure was not possible.¹⁰ However, the difference was not statistically significant.¹⁰ Moreover, a literature review showed that TMA wound healing rates in different studies range from 40% to 70%. Our study found a TMA healing rate comparable to the literature, and it is important to consider that we included only revascularized patients with CLTI and extensive gangrene of the forefoot.

Complications arising in the TMA postoperative period include infections, non-healing, reamputations, and a major amputation. Even so, compared with major amputation, it has a reduced mortality rate and allows for maintenance of ambulatory function.^5,7, 8, 9, 10 Several risk factors are implicated in non-healing TMA, including infection, PAD, kidney disease, heart disease, and DM.7, 8, 9^,18,19 A meta-analysis revealed a positive link between systolic toe pressure ≥30 mmHg and foot wound healing.¹¹ Although there is no objective standard that can be used to predict TMA failure,²⁰ there are different options available for TMA closure.21, 22, 23, 24 The literature suggests that TMA wound closure can lead to greater probability of stump healing.¹⁰ Therefore, TMA coverage must be personalized according to the individual wound characteristics. In our study, we found that rotational flap can be a good option in revascularized patients with PAD and forefoot gangrene, when the long plantar flap is compromised.

The present study has several limitations. The primary limitation is that this is a retrospective single-center study with a small sample size, what might have produced bias and could have reduced the statistical power of the comparisons. Comparative studies with small sample sizes are likely vulnerable to type II statistical errors and should be interpreted with caution. Nevertheless, the sample size can be justified by the prevalence of foot infections in a tertiary care center, where open TMA to control infections are common. Also, only patients who underwent TMA closure were included in the study population. Moreover, as a tertiary referral center, sometimes the patients do not return to the discharging hospital, and follow-up is often carried out in other cities and clinics. Despite these limitations, this study enhances our understanding of the outcomes of a surgical technique that enables TMA coverage in patients with severe foot wounds, where classical plantar flap is not viable. Other techniques can be used for wound closure, and further studies are needed to assess their outcomes. The rotational flap offers an alternative that preserves foot length and function in revascularized patients with extensive defects of plantar forefeet.^14,15

Conclusion

In conclusion, a rotational flap was shown to be a viable alternative to a long plantar flap for TMA closure, demonstrating a satisfactory healing rate in dysvascular foot with additional benefits, including coverage of large plantar flap defects. This study suggests that, for revascularized patients, both rotational flap and classical long plantar flap for TMA closure yield similar outcomes. Larger studies are necessary to compare the different techniques for TMA coverage.

Funding

None.

Disclosures

None.