Keywords
diabetic ulcer - diabetic limb salvage - local flap - incisional NPWT - plantar
Introduction
Diabetic foot ulcers (DFUs) pose a common and significant risk to diabetic patients,
affecting approximately 20% of them throughout their lifetimes.[1] These ulcers are the result of a combination of factors, including neuropathy, peripheral
arterial disease (PAD), deformities, infections, and impaired wound healing.[2] Among DFUs, plantar wounds are particularly challenging due to their weight-bearing
demands and tendency to recur.[3]
Current recommended treatments, primarily conservative dressing,[4] often yield suboptimal results, high dressing utility, slow healing rates, prolonged
treatment durations, high recurrence rates, local wound infection, and complications
leading to amputations.[5] The occurrence of a major amputation in DFU increases the 5-year mortality from
30.5 to 56.6%.[6] Robust healing of plantar ulcers is therefore of paramount importance. The option
to reconstruct these complex wounds and potentially prevent major amputations has
profound effects on the prognosis of a patient. Plastic surgery interventions, such
as skin grafts,[7] local flaps,[8] and free flaps,[9] can positively impact these outcomes. However, skin grafts are less reliable for
plantar wounds, and pedicled and free flaps are complex options typically reserved
for larger defects. Abdelfattah et al popularized the use of thin “expendable” free
soft tissue reconstructions like the superficial circumflex iliac artery perforator
flap to improve outcomes,[10] yet the complexity of free flaps remains a significant limitation.
A few publications have explored the use of local flaps for plantar wound coverage,
albeit with common issues, including prolonged nonweight-bearing periods leading to
noncompliance, wound dehiscence due to high tension, and infection, resulting in complication
rates ranging from 40 to 60%.[8]
[11]
[12] In our multidisciplinary limb salvage service, we conducted a retrospective review
of plantar wound coverage using rotation flaps enhanced by incisional negative pressure
wound therapy (NPWT) to analyze outcomes and establish this technique as an optimal
choice for selected diabetic patients with plantar wounds.
Methods
Patient Selection and Management
Institutional Review Board (IRB ref: 2023/2248) exemption was approved by the IRB
board in Sengkang General Hospital for clinical audit. Informed consent was obtained
from patients to publish their photographs.
We conducted a retrospective review of all patients treated by the Diabetic Limb Salvage
Service in Sengkang General Hospital, which offers comprehensive wound-focused multidisciplinary
care for DFU patients. Demographics including age and gender, comorbidities including
peripheral vascular disease, renal disease, heart disease, HbA1c in diabetes mellitus,
and DFU characteristics including WIfI (Wound, Ischemia, foot Infection) score, staging,
and presence of Charcot foot deformity, were collected. Between March 2020 and July
2023, we treated 250 patients with a total of 262 DFUs. Each patient underwent Peripheral
Arterial Duplex Assessment to evaluate their lower limb vascular status, as well as
wound debridement(s). For patients with significant PAD, significant being defined
as stenosis >50%), angioplasty was performed to enhance blood flow. Following debridement
and infection control, and based on the results of angioplasty, a coverage plan was
developed. For patients without PAD or with PAD that underwent successful angioplasty,
primary closure was undertaken for patients with adequate soft tissue around the wound.
For DFUs smaller than 5 cm and with sufficient local tissue, local flaps were utilized
(see [Supplementary Data 1], available in online version only). In cases where the wound was larger than 5 cm
or where there was insufficient local tissue, free flaps were employed. Patients who
did not achieve satisfactory results from angioplasty were managed conservatively
using NPWT, with eventual split-thickness skin grafting as necessary. In short, the
selection criteria of plantar DFU for rotation flap reconstruction is wound size <5 cm
with adequate local soft tissue and adequate blood supply without PAD or with PAD
but after successful angioplasty ([Fig. 1]). Among these, 78 patients had 82 plantar wounds, and 42 of them underwent rotation
flap closure. Additionally, 11 patients had direct wound closure, 12 received skin
grafts, and 17 underwent free flap reconstruction. The 42 patients who received rotation
flap coverage were included in this study with an average follow-up duration of 11.5
months (ranging from 3 to 30 months). Outcome measures including wound healing rate
and duration, wound recurrence, and amputation were collected.
Fig. 1 Forty-two plantar diabetic foot ulcers (DFUs) received rotation flap coverage out
of 262 DFUs. The indications for rotation flap include wound size < 5 cm with adequate
local soft tissue, and adequate blood supply without peripheral arterial disease (PAD)
or with PAD after successful angioplasty.
Preoperative Optimization
All patients underwent wound debridement and received NPWT with instillation and dwell
(NPWT-id; Veraflo [KCI USA, Inc., San Antonio, TX]). Dwell time: 10 minutes, NPWT
time: 3.5 hours at −125 mm Hg, solution: Granudacyn (Molnlycke Sweden, Inc., Gothenburg)
to expedite local infection control. Empirical antibiotics were initiated, followed
by targeted therapy for positive tissue cultures (see [Supplementary Data 1], available in online version only). Patients who presented with osteomyelitis with
positive bone cultures were given a prolonged course of antibiotics for 6 weeks. Wound
coverage was only performed after the inflammatory marker (C-reactive protein) normalized
and the wound granulation appeared, indicating infection resolution, with a mean duration
of 8.8 (3.1, range: 4–15) days from initial debridement. In cases of Charcot foot
disease, orthopaedic surgeons performed exostectomies during wound debridement for
exposed bony prominence. All patients received vascular assessment via arterial duplex
scans. Patients with significant arterial stenosis (>50% in femoral, anterior tibial,
posterior tibial, and peroneal arteries) underwent angioplasties to augment arterial
inflow before wound reconstruction. Successful angioplasties were defined as <30%
stenosis with good perfusion postangioplasty.
Operative Techniques
A rotation flap was designed, beginning with intradefect triangulation ([Fig. 2]). The size of the flap is designed to be 4 to 6 times the size of the defect. The
flap was raised either laterally or medially based on tissue availability and to avoid
weight-bearing areas, ending with a burrow triangle or VY advancement with angles
between 45 and 60 depending on tissue laxity to facilitate donor-site closure while
advancing the flap. The flap was undermined at the subfascial plane by releasing retaining
ligaments, and the surrounding tissues were undermined at the subcutaneous plane to
enable closure with acceptable tension. Minimal internal sutures (2–3) were used to
approximate the key points during flap inset. A Blake (Johnson & Johnson USA, Inc.,
New Brunswick, NJ) drain was always placed to drain the undermined space. Direct closure
with unabsorbable sutures and staples was performed. Incisional NPWT was applied to
reduce wound tension and facilitate tissue recruitment toward the suture line. Hypafix
tape was often used to augment tissue recruitment over the NPWT dressing and further
reduce tension on the suture line.
Fig. 2 Rotation flap design for diabetic foot ulcer (DFU) plantar wounds. (A) An elliptical plantar wound. (B) Intralesional triangulation (dotted line) for rotation flap design (solid line).
With a defect size of X, the flap size will be 4–6X. (C) Rotation flap with VY closure with angle between 45 and 60 degrees (flap edge: a,
b, and d. Wound edge: a', b', c, c', and d'. Arrows indicating directions of tissue
movement for closure). (D) Final closure after local flap reconstruction (approximated closure points: a and
a' to A; b and b' to B; c and c' to C; d and d' to D).
Postoperative Management
Patients were instructed to avoid weight-bearing on the operated leg for the first
7 days. Wound cultures were monitored, and antibiotics were adjusted accordingly.
After the first wound inspection on postoperative day 7 (POD7) to ensure satisfactory
union, patients began ambulation, wearing an aircast boot with PegAssist Insole (DARCO
USA, Inc., Sunrise, FL), which offloaded the plantar suture lines, in addition to
the incisional NPWT (−125 mm Hg), continued for another 21 days to ensure adequate
wound healing due to the limited healing capacity of the DFUs. Once patients were
assessed by physiotherapy and deemed suitable for home care, they were discharged.
Patients returned weekly for incisional NPWT change and for suture removal on POD21.
After finishing a total of 28 days of NPWT dressing, patients were advised to continue
using the aircast boot until a podiatrist reviews to provide offloading footwear.
While wearing the recommended footwear, F-scan (Tekscan USA, Inc., Norwood, MA) was
performed and if there were any areas of high pressure, a total contact insole or
orthosis was considered.[13] The antibiotic treatment was continued for 2 weeks after wound closure or for 6
weeks, if there were positive bone cultures.
A healed wound is defined as the full epithelialization of wound and wound recurrence
is defined as a wound that reappears at the same site after having previously healed.
Major lower limb amputation is defined as lower limb amputation above the ankle, such
as the below-knee amputation, whereas minor amputation is defined as amputation below
the ankle. The WIfI system[14] was used to assess the wounds at initial presentation. PAD is defined as greater
than 50% stenosis in any of the affected lower limb arteries on arterial duplex scan.
Statistical Analysis
All statistical analyses were conducted using IBM SPSS Statistics ver. 20.0 software
(IBM Co., Armonk, NY). Continuous variables were presented as median (± median absolute
deviation) or mean (± standard deviation) as appropriate, whereas categorical variables
were presented as proportions. The Modified Moody's median test was utilized for median
value comparisons, the Z test was employed for proportional tests, and the Student's
t-test was used for mean variables. A significance value of p < 0.05 was considered statistically significant.
Results
Demographics and Comorbidities
Among the 42 patients who underwent rotation flap reconstruction for their plantar
wounds, the mean age was 60 (36–79) years, with 50% being male. Of the limbs, 45%
(19/42) had PAD (see [Supplementary Data 1], available in online version only), and all of them underwent successful angioplasties.
The mean HbA1c was 8.8% (normal range: 4–5.6%), and 5% (2/42) had end-stage renal
failure (ESRF), whereas 36% (15/42) had chronic kidney disease. Additionally, 33%
(14/42) had ischemic heart disease, and 33% (14/42) had Charcot foot disease. For
the wounds, 41 patients had exposed critical structures including bone, joint, or
tendon (WIfI wound score 2) and 1 patient had calcaneal involvement (WIfI wound score
3). There were 19 forefoot, 17 midfoot, and 6 heel wounds. At presentation, 48% (20/42)
had WIfI grade 4 DFUs, 43% (18/42) had grade 3, and 10% (4/42) had grade 2 ([Table 1]).
Table 1
Demographic and comorbidities of patients' population
Characteristics (n = 42)
|
Value
|
Gender (male)
|
21 (50%)
|
Age (mean ± SD)
|
60 ± 10
|
HbA1c (mean ± SD)
|
8.8 ± 2.75
|
Peripheral artery disease and angioplasty
|
19/42 (45%)
|
ESRF
|
2/42 (5%)
|
CKD
|
15 (36%)
|
IHD
|
14 (33%)
|
Charcot foot deformity
|
14 (33%)
|
WIfI stage
|
|
2
|
4 (10%)
|
3
|
18 (43%)
|
4
|
20 (48%)
|
Abbreviations: CKD, chronic kidney disease; ESRF, end-stage renal failure; IHD, ischemic
heart disease; SD, standard deviation; WIfI, Wound, Ischemia, foot Infection.
Outcomes
All 42 plantar wounds reconstructed using rotation flaps healed initially during the
11.5-month (3–30) follow-up period, with a median wound healing duration of 36 (24)
median (SD) (range: 14–129) days. Out of these, 14% (6/42) patients experienced complications
related to the flap surgery, with two cases of infection requiring further debridement
and secondary closure, and four cases of partial wound dehiscence due to tension that
subsequently healed with dressings and offloading. After the initial wound healing,
21% (9/42) of patients developed a recurrence of their plantar DFUs. Five of them
healed (three after dressing and offloading, and the other two with debridement followed
by secondary closure). However, four of the nine patients with recurrences remained
to have active wounds at the end of the follow-up period. Two of them were managed
conservatively with dressings, whereas the other two suffered infections requiring
further surgical interventions (one ray amputation and one free flap coverage). No
major amputations were performed to treat the recurrent DFUs ([Table 2]).
Table 2
Outcome of rotation flap combined with incisional negative pressure wound therapy
on plantar diabetic foot ulcers
Outcome (n = 42)
|
Value
|
Rate of wound healing
|
42/42 (100%)
|
Duration of wound healing (median ± standard deviation)
|
36 ± 24 d
|
Complications
|
6 (14%)
|
Recurrence
|
9 (21%)
|
Active wound on follow-up
|
4 (10%)
|
Major amputation
|
0 (0%)
|
Minor amputation
|
1 (2.4%)
|
In subgroup analysis, patients with Charcot foot deformity (14/42) had significantly
higher rates of wound recurrence (43%; 6/14) and nonhealing wounds (29%; 4/14), compared
with non-Charcot foot group (11% [3/28] and 0% [0/28]; p = 0.017 and 0.003, respectively; [Table 3]).
Table 3
Outcome comparison between patients with Charcot foot deformity versus without Charcot
foot deformity
|
Non-Charcot foot (n = 28)
|
Charcot foot (n = 14)
|
p-Value
|
Wound healing duration
|
39.8 ± 22
|
45.3 ± 27
|
0.48
|
Recurrence
|
3 (11%)
|
6 (43%)
|
0.017
|
Active wound
|
0 (0%)
|
4/14 (29%)
|
0.003
|
For the 31 patients with follow-up HbA1c levels available between 3- and 6-month postsurgery,
a significant improvement was observed, with HbA1c levels decreasing from 9.1% (2.6)
to 7.2% (1.8) (p = 0.000496).
Additional Procedures
Additional orthopaedic procedures were recorded such as tendoachilles lengthening
(n = 4), and corrective orthopaedic interventions (n = 2). Tarsal tunnel release procedures were performed in patients with symptomatic
neuropathy and positive Tinel's sign (n = 8), either simultaneously with wound closure or posthealing.
Three case studies illustrate the use of rotation flaps in diabetic plantar wound
reconstruction:
Case 1 had a deep forefoot plantar ulcer with systemic inflammatory response syndrome
(SIRS) and a WIfI grade 4 DFU. The resultant defect postdebridement measured 3 cm × 4 cm
with exposed metatarsophalangeal joints. A rotation flap was used to reconstruct the
plantar ulcer, which subsequently healed without complications ([Fig. 3]).
Fig. 3 Patient A with forefoot wound reconstructed with rotation flap. (A) A 3 cm × 4 cm defect exposing second metatarsophalangeal joint. (B) Rotation flap design over lax tissue at medial instep. (C) Flap inset. (D) One week postoperatively before starting ambulation. (E) One month postoperatively with complete wound healing while ambulating.
Case 2 presented with an extensive midfoot plantar abscess and SIRS with a background
of Charcot foot (WIfI grade 4). The defect postdebridement measured 3 cm × 5 cm with
exposed bone and joints. A rotation flap was used for wound reconstruction, leading
to an uneventful healing process, enabling the resumption of ambulation with a total
contact insole ([Fig. 4]).
Fig. 4 Patient B with Charcot foot deformity and a plantar ulcer measuring 2 cm × 5 cm with
exostectomy performed during debridement. (A) The midfoot defect with exposed bone at wound base. (B) Rotation flap design over medial instep. (C) Flap inset to reconstruct the defect. (D) One week postoperatively, wound was healing well before starting ambulation. (E) Healed wound at one month while ambulating, wearing prescribed off-loading footwear
(seen in background).
Case 3 had extensive forefoot infection and SIRS (WIfI grade 4 DFU) with past medical
history including a previous fifth toe ray amputation and ESRF. The resultant forefoot
wound measured 2 cm × 5 cm. It was covered with a rotation flap, leading to complete
healing, and the patient regained her premorbid ambulatory status ([Fig. 5]).
Fig. 5 Patient C with end-stage renal failure and previous 5th ray amputation presented
with (A) a 5 cm × 3 cm forefoot wound exposing tendon and bone. (B) Rotation flap over lateral forefoot laxity from previous ray amputation. (C) Flap inset to reconstruct the defect. (D) Wound closure intraoperatively. (E) Wound well healed 6 weeks postoperatively while ambulating on customized footwear.
Discussion
Our study demonstrates the safe and efficient reconstruction of plantar wounds using
rotation flap. We achieved a remarkable 100% initial wound healing rate after the
flap reconstruction with a median duration of 36 days, surpassing the literature's
reported median plantar DFU wound closure rate of 77% at 3 months[15] with conventional treatment. In addition to the impressive healing rate, our approach
also resulted in a lower recurrence rate of 21% compared with the 30 to 40% recurrence
rates reported in the literature,[3]
[5]
[15] which, in turn, contributed to reduced major and minor amputations.
These favorable outcomes can be attributed to several key advantages of rotation flap
reconstruction. First, this method utilizes tissue reconstruction that is like-for-like,
providing the necessary durability for ambulation and the internal structural support
required during ambulation.[16] Second, the utilization of rotation flaps simplifies the surgical procedure, eliminating
an extra donor wound in skin grafting and the complexity associated with free flap
coverage. Finally, our protocol incorporates incisional NPWT[17]
[18] and offloading, allowing for early and safe ambulation as early as POD7, in contrast
to the commonly recommended wait of 21 days found in the literature.[11]
[19] This early ambulation significantly contributes to improved patient compliance and
rehabilitation, resulting in a 100% patient compliance rate, and regaining ambulatory
status, while maintaining excellent wound healing outcomes. Furthermore, 90% (38/42)
of patients remained ambulatory without wound at the end of this study, whereas the
remaining 10% (4/42) ambulated with assistance to offload the active plantar ulcer.
However, the application of local flaps for primary wound closure has traditionally
been limited due to a high complication rate, varying between 40 and 60% as reported
in various literature sources.[11]
[12] This elevated complication rate can be attributed to factors such as poor wound
healing potential, infection, vascular insufficiency, tension, and wound dehiscence.
Our treatment approach effectively addresses these factors, leading to improved wound
closure rates and a reduction in complications.
Hyperglycemia has been found to be detrimental to wound healing.[20] Our study places a strong emphasis on strict diabetic control throughout the treatment
process with twice weekly medication adjustment augmented with dietary modification
by a dietitian. Wound closure was only considered when patients achieved acceptable
glucose control. Furthermore, all patients with HbA1c levels exceeding 8.0% received
an outpatient dietitian review and were provided with self-glucose monitoring devices.
This proactive approach led to a significant reduction in HbA1c levels within our
patient cohort from 9.1 to 7.2%, contributing to the high rate of wound healing.
For infected DFUs, achieving infection-free wounds is a prerequisite for flap surgery.
Our protocol was meticulously designed to systematically address this issue. All patients
were initiated on empirical antibiotics and underwent wound debridement within 24 hours
to minimize the impact of infection. NPWT with instillation system of Granudacyn solution
was applied either intraoperatively or on POD1 to treat the infection.[21] Culture-directed antibiotics were adjusted as soon as debridement culture results
became available. The continuous treatment with antibiotics and topical antiseptics
effectively eliminated residual infection, leading to a transition from catabolism
to anabolism, marked by normalizing C-reactive protein levels.[22] Such a metabolic transition was critical for improving angiogenesis[23] and wound healing potential,[24] which were essential for successful DFU reconstruction.
Intraoperatively, to minimize foreign material as a nidus for infection, we employed
minimal internal sutures with antibiotic-coated absorbable sutures (Vicryl 2/0; Johnson
& Johnson USA, Inc., New Brunswick, NJ), and a Blake drain was always placed to ensure
the drainage of hematoma and seroma. Adequate duration of antibiotic treatment (2
or 6 weeks) was given to ensure the complete resolution of infection and optimal wound
healing. With these protocols in place, we achieved a lower infection rate of 5% (2/42)
after rotation flap reconstruction.
The success of flap procedures is critically dependent on addressing vascular insufficiency.
PAD is common in DFUs, affecting up to 40 to 50% of cases. In our series, 45% (19/42)
of patients had peripheral artery disease, and all of them received successful angioplasty
within 7 days before wound closure to ensure excellent arterial inflow with minimal
restenosis. The flap design maintained sufficient dermal and subdermal plexus blood
supply to the flap. Limited undermining helped preserve perforators, and the inclusion
of the medial plantar perforator at the flap base was preferred during the design.
In addition to good arterial inflow, venous outflow is equally important for flap
survival. The preservation of a skin bridge and limited undermining helped maintain
venous return.[25] With these considerations, the random flap maintained ample vascular supply, allowing
for healing even when closed with some degree of tension.
Excessive tension at the wound edge is the primary cause of wound dehiscence. To minimize
such complications, we initiated a multifaceted approach beginning with patient selection.
Only patients with wounds width less than 5 cm and who had ample plantar soft tissue
were chosen for rotation flap reconstruction. During surgery, incisions were strategically
placed away from weight-bearing areas to minimize tension during future ambulation.
In addition to flap undermining, we also undermined the surrounding wound edge to
allow for mobilization of the surrounding soft tissue, thus reducing the tension required
for closure. Internal sutures were employed to bring the wound edges together at the
deep fascia level to reduce tension on skin closure.
Further tension relief was achieved by employing incisional NPWT following wound closure.
Numerous studies have demonstrated the effectiveness of incisional NPWT in enhancing
wound healing for high-tension closures, such as those in breast surgeries,[26] lower limb procedures,[27] abdominal,[28] and perineal wounds.[29] The dressing redistributes tension from the suture line to adjacent intact skin,
promoting minimal tension at the suture line for healing. After the initial wound
inspection on POD7, patients transitioned to weight-bearing on the operated site using
an aircast boot. The boot not only immobilized and offloaded the plantar surface but
also allowed incorporation of the incisional NPWT for an additional 3 weeks. Controlled
weight-bearing enabled patients to be discharged home and to continue essential activities
of daily living, thereby reducing noncompliance rates associated with nonweight-bearing
protocols.
Through the combined implementation of these techniques, all 42 plantar wounds in
our study successfully healed following rotation flap closure, with a complication
rate of only 14% (6/42), which is notably lower than the 35 to 60% reported in existing
literature.[11]
[12]
[19]
Recurrence
The management of DFUs has historically been plagued by a high annual recurrence rate
of 40%.[3]
[5] Other studies have reported lower recurrence rates by using rotation flap for plantar
ulcer coverage, but these studies only included patients with noninfected chronic
DFUs.[11]
[19] Our study, however, included patients presenting with acute infections, in whom
a higher baseline recurrence rate of 30 to 40% was anticipated, aligning with that
of the broader DFU demographic.
To mitigate the recurrence of DFUs in our patient cohort, comprehensive podiatric
assessments were conducted to ensure the provision of appropriate footwear. Despite
these efforts, a recurrence rate of 21% (9/42) was observed. Initial recurrence management
strategies included enhanced offloading techniques, such as the use of total contact
insoles, orthoses, and personal mobility aids. These interventions lead to wound healing
in five patients, whereas the remaining four, all of whom had Charcot foot deformity,
continued to have persistent plantar wounds.
In subgroup analysis, it was observed that patients with Charcot foot deformity exhibited
significantly higher recurrence rates and a higher rate of active wounds at follow-up
([Table 3]). This finding aligns with that seen in the literature,[30] highlighting the high risk of DFUs with Charcot foot deformity and underscoring
the importance of optimizing offloading and the need for corrective orthopaedic procedures.
Limitations
This study is a single-center, retrospective review of rotation flap reconstruction.
The cohort is relatively small, with a relatively short duration of follow-up. We
plan to include more patients with longer follow-up in future studies.
Conclusion
In conclusion, our study demonstrates that rotation flap closure is a safe and effective
option for selected infected DFU patients. With our comprehensive protocol, early
ambulation, high rates of wound healing, and low complication rates, are achievable.
During follow-up, with proper offloading, low recurrence rates are observed in patients
without Charcot foot deformity. On the other hand, the relatively high rate of recurrence
and active wounds in patients with Charcot foot deformity underscores the importance
of corrective orthopaedic reconstructive procedures to address the underlying structural
deformities.
Supplementary Data S1