Journal of
Clinical Medicine
Article
Safety and Efficacy of Several Versus Isolated Prophylactic
Flexor Tenotomies in Diabetes Patients: A 1-Year
Prospective Study
Mateo López-Moral 1,2 , Raúl J. Molines-Barroso 1,2, *, Yolanda García-Álvarez 1,2 , Irene Sanz-Corbalán 1,2 ,
Aroa Tardáguila-García 1,2 and José Luis Lázaro-Martínez 1,2
1
2
*
Citation: López-Moral, M.;
Molines-Barroso, R.J.; García-Álvarez,
Y.; Sanz-Corbalán, I.;
Tardáguila-García, A.;
Lázaro-Martínez, J.L. Safety and
Efficacy of Several Versus Isolated
Prophylactic Flexor Tenotomies in
Diabetes Patients: A 1-Year
Prospective Study. J. Clin. Med. 2022,
Diabetic Foot Unit, Facultad de Enfermería, Fisioterapia y Podología, Universidad Complutense de Madrid,
28040 Madrid, Spain; matlopez@ucm.es (M.L.-M.); ygarci01@ucm.es (Y.G.-Á.); irsanz01@ucm.es (I.S.-C.);
aroa.tardaguila@ucm.es (A.T.-G.); diabetes@ucm.es (J.L.L.-M.)
Instituto de Investigación Sanitaria del Hospital Clínico San Carlos (IdISSC), 28040 Madrid, Spain
Correspondence: rmolines@ucm.es; Tel.: +34–913942218
Abstract: Background: To assess long-term clinical outcomes of patients who underwent isolated
versus several percutaneous flexor tenotomies for the treatment of toe deformities and previous
diabetic foot ulcers; Methods: Twenty-three patients (mean age 66.26 ± 11.20, years) who underwent
prophylactic percutaneous flexor tenotomies secondary to tip-toe ulcers participated in this 1-year
prospective study. The study was stratified into two groups for analyses: (1) isolated tenotomies
patients, and (2) several tenotomies patients (two or more tenotomies). Outcome measures were
toe reulceration and recurrence, minor lesions, digital deformities, and peak plantar pressure (PPP—
N/cm2 ) and pressure/time Integral (PTI—N/cm2 /s) in the hallux and minor toes after a 1-year
follow-up period; Results: Patients with isolated tenotomies (n = 11, 35.48%) showed a higher rate of
reulceration (n = 8, 72.7%, p < 0.001) in the adjacent toes, additionally, we found more prevalence of
hyperkeratosis (n = 11, 100%), minor lesions (n = 9, 81%), and claw toes (n = 11, 100%) (p < 0.001).
In several tenotomies patients (n = 20, 64.52%), we found a higher rate of floating toes (n = 16, 80%)
in comparison with isolated tenotomies patients (p < 0.001). PPP and PTI in the non-tenotomy toes
were higher in the group of patients who underwent isolated tenotomies (p < 0.001); Conclusions:
Patients who underwent several tenotomies had better clinical outcomes after a 1-year follow-up
period compared to isolated tenotomies.
11, 4093. https://doi.org/10.3390/
jcm11144093
Keywords: diabetic foot; surgery; deformity; prevention
Academic Editor: Claire J. Stocker
Received: 7 June 2022
Accepted: 13 July 2022
Published: 14 July 2022
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4.0/).
1. Introduction
Diabetic foot ulcers (DFU) on the dorsal and plantar aspects of the toes have become
one of the most common locations of ulcer occurrence in the foot [1], reaching a total
prevalence of foot ulceration that ranges from 43% to 55% [2]. Although toe ulcers are
smaller than the metatarsal head, midfoot, or rearfoot ulcers, they are misdiagnosed and
tend to have higher rates of foot amputation compared to other locations of the foot [3].
Motor neuropathy leads to atrophy of intrinsic foot muscles (interossei and lumbricals);
when the intrinsic muscles become atrophic and overpowered by the extrinsic muscles, the
stabilizing action is lost, which may eventually result in claw or hammer toes [4]. Those toe
deformities have been linked to callus formation secondary to higher plantar pressures [5].
In persons with diabetes and neuropathy, the toe deformity increases plantar pressures
during midstance and toe-off, which can result in abundant callus formation, minor lesions,
and ultimately toe ulceration in the tip of the toes [6]. Off-loading and debridement of tiptoe ulcers are the basis of the treatment to achieve ulcer healing; despite this, conservative
treatment via orthotic interventions, such as therapeutic footwear, toe spacers, or padding,
remains unclear and has a weak level of evidence [7].
J. Clin. Med. 2022, 11, 4093. https://doi.org/10.3390/jcm11144093
https://www.mdpi.com/journal/jcm
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Flexor tendon tenotomies have been demonstrated to be an effective, safe, and easy
procedure that is advocated for flexible toe deformities and can be performed prophylactically or curatively to alleviate the focal pressure on ulcerated areas [8]. The International
Working Group Diabetic Foot (IWGDF) recommends performing digital flexor tendon
tenotomies in a person with diabetes and abundant callus or an ulcer on the apex or distal
part of a non-rigid hammer toe to prevent the first ulcer or the development of a recurrent
foot ulcer [9]. Digital flexor tendon tenotomies have been demonstrated to reduce the risk
of recurrences in the tip of the toes relative to other non-surgical techniques [10–12]. A
previous systematic review reported 250 flexor tenotomy procedures performed in 163 patients [13]; the included studies generally reported good healing rates (92–100% within two
months post-operative follow-up), and relatively few recurrences during a middle-term
follow-up (0–18% at 22 months median post-operative follow-up). Conservative surgery
procedures, such as metatarsal head resection, Achilles tendon lengthening, or joint arthroplasty resection, have shown high reulceration rates, indicating that prophylactic surgery
could reduce the safety of this procedure [14]. Several authors reported transfer ulcers on
adjacent toes due to transferred pressure [11,12,15].
Flexor tendon tenotomies are widely used to treat and prevent toe ulcers, despite this,
no previous research has analyzed outcomes after percutaneous flexor tendon tenotomies
and if there exists any relationship between patients with several versus isolated tenotomies.
We hypothesize that implementing several percutaneous flexor tenotomies in patients
with previous tip-toe ulcers can reduce the reulceration rate in comparison with isolated
percutaneous flexor tenotomies.
Therefore, the principal aim of this study was to assess the long-term clinical outcomes
of patients who underwent isolated versus several percutaneous flexor tenotomies for the
treatment of toe deformities and previous diabetic foot ulcers.
2. Materials and Methods
2.1. Subjects
Twenty-three patients who underwent percutaneous flexor tenotomies secondary to
tip-toe ulcers participated in this 1-year prospective study in a specialized diabetic foot
unit between April 2019 and January 2021. All the patients included in the study suffered
from a previous orthopedic treatment failure, defined as ulcer recurrence in the same toe
by using toe spacers and therapeutic footwear modifications [9].
The inclusion criteria were confirmed type 1 or type 2 diabetes, age > 18 years, affected
with flexible toe deformities, history of tip-toe DFU, and loss of protective foot sensation
because of peripheral neuropathy (DPN).
Exclusion criteria were ulcers during the examination, transmetatarsal or major amputation in the contralateral limb (below or above the knee), history of rheumatoid disease,
other causes of neuropathy, critical limb ischemia as defined according to the IWGDF
guidance [16], and the need for walking aids. Patients with previous toe surgery were also
excluded (both musculoskeletal and soft tissue procedures).
After institutional review, board approval was obtained, and patients’ medical records
and clinicopathologic conditions were recorded. Ethical approval was obtained (19/173-E)
on 30 April 2019, and the study was completed following the ethical standards of the
responsible committee. Informed consent was obtained from each patient. The authors
declare that they complied with the code of ethics of the Declaration of Helsinki [17].
2.2. Clinical Evaluation
At baseline, clinical characteristics were collected in the case report form (CRF) after
the patient signed informed consent on day zero. Body mass index (BMI) was calculated
as weight (kg) divided by height (m2 ). Clinicopathologic data, including diabetes type,
hypertension, and HbA1c (%) values in the previous 3 months were collected. The patients’
renal, cardiac, and retinopathy status and previous minor amputation were recorded in the
clinical record form from the patient’s clinical history. DPN was diagnosed according to the
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inability to sense the pressure of a 10-g Semmes-Weinstein monofilament at three plantar
foot sites and/or a vibration perception threshold >25 V as assessed using a biothesiometer
(Me.Te.Da. s.r.l., Via Silvio Pellico, 4, 63074 San Benedetto del Tronto, Italy) [18]. According
to the IWGDF guidelines, critical limb ischemia is defined as the absence of both distal
pulses and a brachial ankle index of <0.39, systolic ankle pressure <50 mmHg, and toe
pressure <30 mmHg [19].
2.3. Percutaneous Flexor Tendon Tenotomy Procedure
Patients were subject to a biomechanical assessment. First, the flexibility of the deformity was evaluated using the Kellikian push-up test [20]. If the deformity was corrected
by applying pressure at the base of the metatarsophalangeal joint (MTPJ), it was then
considered flexible; in contrast, the persistence of clawing or hammer indicated a rigid
deformity [20,21]. Patients with flexor tenotomy indications were those patients with
previous DFU on the tip of the toe. No patient with curative indication was included in
the study [22]. The procedure consisted of locating the flexor tendon by placing it under
tension followed by a subsequent transversal incision in the flexor digitorium longus and
brevis (both for minor toes and hallux) in the proximal portion of the proximal phalanx
(Figure 1). The wound following the tenotomy was sutured [14]. All the procedures were
performed by the same senior surgeon (JLLM) in the same operating room. The patients
received postoperative antibiotic prophylaxis with amoxicillin/clavulanic acid 875/125
mg, 1 g every 8 h, starting just after the procedure and continuing for a week. The patient
was asked to walk with a post-op extra depth shoe for 7 days. The suture was removed
after 7 days, and then the patient was asked to wear extra-depth therapeutic footwear with
a fully customized insole to decrease peak pressures in the plantar aspect of the foot [23].
Figure 1. Toe deformities evaluated in the study. (Left), 2nd, 3rd, and 4th claw toe secondary to hallux
flexor tenotomy; (right), 2nd, 3rd, 4th, and 5th floating toes secondary to several flexor tenotomies
(all toes); (down), minor lesion in the tip of the 3rd toe.
Patients were subjected to isolated tenotomies when only one toe was affected with a
previous toe ulcer, several tenotomies were performed in patients with one or more toes
affected with previous toe ulcers, and in addition, any of the remaining toes were affected
with a flexible toe deformity.
2.4. Plantar Pressure Measurement
A dynamic pressure measurement system (Footscan® system, RSscan International,
3583 Olen, Belgium) was used to record the peak plantar pressure (PPP) (N/cm2 ) and
pressure-time integral (PTI) (N/cm2 /s) in the dynamic barefoot condition after a 1-year
follow-up period. The hardware included a 2-m plate with four sensors/cm2 and a 3D-Box
interface that was synchronized with a motion capture system. All data were recorded at a
measurement frequency of 500 Hz and were processed using Scientific Footscan® software
(RSscan International, 3583 Olen, Belgium). To accommodate the patient to the normal gait
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and speed, patients were instructed to walk barefoot for 3 min before measuring the plantar
pressure. After this, four registers were taken to calculate the mean of both measurements
(PPP and PTI) with a two-step approach to the platform [24]. The software divides every
foot into ten sectors: the hallux, toes, first to fifth metatarsal head, midfoot, medial heel, and
lateral heel. For the analyses, only the hallux and minor toes were extracted and evaluated
to assess changes in barefoot pressure after tenotomy procedures. The investigator who
analyzed and extracted data from PPP and PTI parameters was blinded to the clinical data
from every patient; both investigators are experienced podiatrists with more than 5 years
of experience in the treatment of diabetic foot complications. All clinical evaluations were
carried out in a specialized biomechanics laboratory.
2.5. Follow-Up
All patients were followed up for 1 year. Patients came monthly to the outpatient
clinic, according to the international guidelines [9]. At every visit, the principal investigator
performed debridement of high-risk points, such as minor lesions or hyperkeratosis.
2.6. Outcome Measures
The main outcome measure was to assess the presence of percutaneous flexor tenotomies clinical outcomes after a 1-year follow-up period. Toe reulceration and recurrence
were defined according to the IWGDF guidelines as a break of the skin of the foot that
involves, as a minimum, the epidermis and part of the dermis, in a different toe than the
previous toe and the same toe, respectively [25].
Minor lesions were defined as nonulcerative lesions of the skin on the plantar aspect of
the tip of the toes and included abundant callus, hemorrhage, or a blister [26]. The following
digital deformities were assessed: Claw toes were considered only when the proximal
phalanx was extended. Floating toes were defined when all the metatarsophalangeal and
interphalangeal joints were in hyperextension position, and the tip of the toe did not contact
the floor [27] (Figure 1).
The secondary outcome measure was to evaluate the differences between groups in
barefoot pressures after the flexor tenotomy procedure in the hallux and the minor toes.
The investigator who assessed DFU ulceration and foot biomechanics was blinded to
the percutaneous flexor tenotomy procedure to avoid bias in outcome interpretation.
2.7. Statistical Analyses
The assumption of the normality of all continuous variables was verified using the
Kolmogorov-Smirnov test. Quantitative variables were presented as the mean and standard
deviation (SD), while qualitative variables were presented as percentages and frequencies.
To explore differences in clinical features between patients with several versus isolated tenotomies, the Chi-square test for categorical variables and the Student’s t-test for quantitative
variables were performed. p-values < 0.05 were considered statistically significant, with
confidence intervals of 95%. All statistical analyses were performed using SPSS statistics
version 25.0 for Mac OS (SPSS, Chicago, IL, USA). The study was stratified into two groups
for analyses: (1) isolated tenotomies patients, and (2) several tenotomies patients (two or
more tenotomies). A secondary multiple comparison sub analysis (Bonferroni test) was
performed between the subgroups of tenotomy patients (one tenotomy, three tenotomies,
four tenotomies, and five tenotomies) for the primary outcome measure.
The sample size calculation based on a 28-month follow-up study of patients with
previous flexor tenotomy of the flexor digitorium longus to heal tip toe ulcers [10] showed
a recurrence rate of 12.1%. As a relevant risk reduction, we assumed a difference in the
recurrence rate of 20%. With a 0.05 setting (one-sided), power of 0.80 in a ×2 analysis,
and an anticipated loss to follow-up of 20%, we intended to include 30 patients. Because
of the low recruitment rate, the actual sample size was 23, which, yielded powers of 0.67
(one-sided) and 0.56 (two-sided).
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3. Results
From the 23 patients included in the study, eight (34.8%) patients underwent tenotomies in both feet, and 15 (65.2%) underwent tenotomies in only one foot. A total of 99
tenotomy procedures were performed, all as prophylactic procedures. Baseline data on
demographic characteristics and diabetes complications are shown in Table 1.
Table 1. Differences between the risk factors for tenotomy groups (N = 23).
Baseline Characteristics
All Patients (N = 23)
Isolated Tenotomies
Patients (n = 11)
Several Tenotomies
Patients (n = 12)
p-Value
[95% CI]
Male, n (%)
Female n, (%)
Type 2 Diabetes, n (%)
Type 1 Diabetes, n (%)
Retinopathy, n (%)
Nephropathy, n (%)
Hypertension, n (%)
Hypercholesterolemia, n (%)
Cardiovascular disease, n (%)
Neuropathy, n (%)
Previous Ulceration, n (%)
Permeable Pedal Pulses, n (%)
Ankle Brachial Pressure Index,
mean ± SD
Toe Brachial Pressure Index,
mean ± SD
Transcutaneous Oxygen
Pressure (mmHg), mean ± SD
Mean age ± SD (years)
Glycated hemoglobin
mmol/mol (%), mean ± SD
Diabetes mellitus (years),
mean ± SD
Body Mass Index (kg/cm2 )
20 (87.0%)
3 (13.0%)
22 (95.7%)
1 (4.3%)
12 (52.2%)
4 (17.4%)
18 (78.3%)
22 (95.7%)
11 (47.8%)
11 (100%)
31 (100%)
16 (69.6%)
10 (90.9%)
1 (9.1%)
10 (90.9%)
1 (9.1%)
5 (45.5%)
2 (18.2%)
6 (54.5%)
11 (100%)
3 (27.3%)
11 (100%)
11 (100%)
8 (72.7%)
10 (83.3%)
2 (16.7%)
12 (100%)
7 (58.3%)
2 (16.7%)
12 (100%)
11 (91.7%)
8 (66.7%)
12 (100%)
12 (100%)
8 (66.7%)
0.590
0.537
0.924
0.008 *
0.328
0.006
0.752
1.18 ± 0.33
1.17 ± 0.28
1.19 ± 0.39
0.877
0.76 ± 0.15
0.78 ± 0.13
0.75 ± 0.17
0.609
30.08 ± 6.90
28.81 ± 7.09
31.25 ± 6.82
0.412
66.26 ± 11.20
68.9 ± 10.39
63.83 ± 11.81
0.288
7.54 ± 1.33
7.38 ± 1.34
7.69 ± 1.36
0.590
14.69 ± 11.63
15.35 ± 15.35
13.08 ± 7.11
0.500
30.15 ± 3.73
28.36 ± 3.16
31.79 ± 3.56
0.002 *
SD, standard deviation; kg, kilograms;
cm2 ,
0.286
squared centimeters. * p < 0.05 indicates statistical significance.
Regarding demographic characteristics and diabetes complications, we found that
patients who underwent several tenotomies had more prevalence of hypertension and
higher BMI values than isolated tenotomies patients (Table 1).
A total of 31 feet were analyzed, of which 11 feet (35.5%) underwent isolated tenotomies, and 20 (64.2%) underwent several tenotomies. All the post-operative cures healed
in a median time of 10 IQR days (range, 7–14 days). During the follow-up period, no feet
developed a recurrence event; in addition, eight (25.8%) feet developed a reulceration event
in the following locations: five (62.5%) patients developed a transfer lesion to the third
toe after tenotomy of the second toe, one (12.5%) patient developed a transfer lesion to
the second toe after tenotomy of the first toe, and two (25%) patients developed a transfer
lesion to the fourth toe after tenotomy of the third toe. Feet characteristics are shown in
Table 2.
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Table 2. Feet characteristics (N = 31).
Feet Characteristics
Feet (N = 31)
Number of Tenotomies, n (%)
One
Two
Three
Four
Five
Ulcer Recurrence, n (%)
Reulceration, n (%)
Callus Formation, n (%)
Minor Lesion, n (%)
Adjacent Floating Toe, n (%)
Adjacent Claw Toe, n (%)
Peak Plantar Pressure beneath Hallux, (N/cm2 )
Pressure Time Integral beneath Hallux, (N/cm2 /s)
Peak Plantar Pressure beneath minor toes, (N/cm2 )
Pressure Time Integral beneath minor toes, (N/cm2 /s)
11 (35.5%)
0 (0%)
4 (12.9%)
4 (12.9%)
12 (38.7%)
0 (0%)
8 (25.8%)
11 (35.5%)
9 (29%)
17 (54.8%)
12 (38.7%)
0.26 ± 0.22
0.09 ± 0.10
0.57 ± 0.71
0.31 ± 0.4
N, Newton; cm2 , squared centimeters; s, seconds.
Main Outcome
Patients with isolated tenotomies (n = 11, 35.48%) showed a higher rate of reulceration
(n = 8, 72.7%) secondary to transfer lesions in the adjacent toes in a median time of nine and
half weeks (IQR, 8–10.75 weeks). In addition, in the adjacent toes, we found more prevalence of hyperquerathosis (n = 11, 100%) in a median time of five weeks (IQR, 4–6 weeks)
and minor lesions (n = 9, 81%) in a median time of six and a half weeks (IQR, 6–7.75 weeks).
Adjacent claw toes were found in the group of patients who underwent isolated tenotomies
(n = 11, 100%) in a median time of five weeks (IQR, 4.25–6 weeks). Barefoot peak pressure
(1.48 ± 0.26 N/cm2 ) and integral pressure time (0.83 ± 0.11 N/cm2 /s) in the non-tenotomy
toes were higher in the group of patients who underwent isolated tenotomies. Finally, in
the group of patients who underwent several tenotomies (n = 20, 64.52%), we found a
higher rate of floating toes (n = 16, 80%) in comparison with isolated tenotomies patients in
a median time of four weeks (IQR, 2–4) (Table 3).
Table 3. Differences between the risk factors for tenotomy groups.
Baseline Characteristics
Number of Tenotomies, n (%)
One
Two
Three
Four
Five
Ulcer Recurrence, n (%)
Reulceration, n (%)
Callus Formation, n (%)
Minor Lesion, n (%)
Adjacent Floating Toe, n (%)
Adjacent Claw Toe, n (%)
Peak Plantar Pressure beneath
Hallux, (N/cm2 )
Pressure Time Integral beneath
Hallux, (N/cm2 /s)
Peak Plantar Pressure beneath
minor toes, (N/cm2 )
Pressure Time Integral beneath
minor toes, (N/cm2 /s)
Feet with
Isolated Tenotomies (n = 11)
Feet with
Several Tenotomies (n = 20)
p-Value [95% CI]
11 (100%)
8 (72.7%)
11 (100%)
9 (81.8%)
1 (9.1%)
11 (100%)
4 (20%)
4 (20%)
12 (60%)
0
0
0
16 (80%)
1 (20%)
<0.001 *
<0.001 *
<0.001 *
<0.001 *
<0.001 *
0.31 ± 0.18
0.14 ± 0.23
0.04 *
0.13 ± 0.08
0.07 ± 0.14
0.09
1.48 ± 0.26
0.07 ± 0.17
<0.001 *
0.83 ± 0.11
0.03 ± 0.08
<0.001 *
N, Newton; cm2 , squared centimeters; s, seconds. * p < 0.05 indicates statistical significance.
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After adjusting the results by the number of procedures performed, several tenotomies
(patients who underwent three, four, and five procedures) showed to be more effective in
reducing the reulceration rate in comparison with one tenotomy patients (Table 4).
Table 4. Multiple comparison analyses between tenotomy groups.
Number of Tenotomies
Performed
Reulceration
p-Value
[95% CI]
One-tenotomy reulceration
patients
(n = 8)
Three
Four
Five
0 (0%)
0 (0%)
0 (0%)
<0.001 * [0.25–1.19]
<0.001 * [0.25–1.19]
<0.001 * [0.38–1.06]
Three-tenotomies reulceration
patients
(n = 0)
One
Four
Five
8 (72.7%)
0 (0%)
0 (0%)
<0.001 * [−1.19–0.25]
1.00 [−0.57–0.57]
1.00 [−0.46–0.46]
Four-tenotomies reulceration
patients
(n = 0)
One
Three
Five
8 (72.7%)
0 (0%)
0 (0%)
<0.001 * [−1.19–0.25]
1.00 [−0.57–0.57]
1.00 [−0.46–0.46]
Five-tenotomies reulceration
patients
(n = 0)
One
Three
Four
8 (72.7%)
0 (0%)
(0%)
<0.001 * [−1.06–0.38]
1.00 [−0.46–0.46]
1.00 [−0.46–0.46]
* p < 0.05 indicates statistical significance.
4. Discussion
We found that patients who underwent several tenotomies had better clinical outcomes, such as lower reulceration rates, fewer minor lesions, less hyperkeratosis, and fewer
claw toes in the adjacent toes. In addition, patients who underwent several tenotomies resulted in lower barefoot pressures beneath the hallux and minor toes, resulting in reducing
the risk of these areas developing a new ulcer event. The data from this research support
that patients with previous toe ulcers or thick calluses in the tip of the toe should undergo
percutaneous flexor tenotomies in all the toes to reduce long-term complications.
Previous studies have analyzed transfer lesions that occurred after flexor tenotomies:
Rasmussen et al. [12] found two transfer lesions (7%) 20 to 28 weeks after surgery, Tamir
et al. [15] found nine transfer lesions (9%) eight weeks after surgery, and Van Netten
et al. [11] found eight transfer lesions (21%). It is unfortunate that this latter cited study
did not report the time to develop a transfer lesion, and additionally, they did not evaluate
if the number of tenotomies implemented could influence the clinical outcome. To our
knowledge, no prior study has evaluated if reulceration after flexor tenotomies can be
related to isolated or several tenotomies in the affected foot. We found that eight feet (38.1%)
of the sample developed a reulceration event and eight (72.7%) in the isolated tenotomies
group, but no patients developed a recurrent event during the follow-up period. Regarding
the time to suffer the reulceration event after tenotomies, Tamir et al. [15] found the time to
reulcerate was eight weeks, similar results compared to ours, with a median time of nine
and a half weeks in the isolated tenotomy group. However, Rasmussen et al. [12] found
that patients who suffered from a reulceration event developed transfer lesions five and
seven months after surgery, which is longer than in our results, which could be explained
by Rasmussen et al. not following the patients on a monthly basis after healing, as IWGDF
guidelines recommend. The only study that evaluated the location of the tenotomy and
the reulceration found that after tenotomy of the hallux, two patients developed transfer
lesions to the tip of the second toe, which is consistent with the results reported here [12].
Toe deformities after flexor tenotomies have only been evaluated in one prior study [11].
These authors found that one patient developed a dorsal ulcer secondary to dorsiflexion of
the metatarsophalangeal joint, and in that respect, we found that all the patients subjected
to isolated tenotomy developed a claw toe in the adjacent toe with no dorsal ulcer. The
fact that our patients did not develop a dorsal ulcer might be related to the extra-depth
therapeutic footwear.
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To our knowledge, no previous research has evaluated the development of calluses
and minor lesions in patients after prophylactic tenotomies; our research showed that
patients who underwent isolated tenotomies suffered from high rates of calluses and minor
lesions in comparison with the group of several tenotomies that did not show any calluses.
In fact, this research is the first to evaluate barefoot pressures after tenotomy procedures,
which could be linked to the appearance of calluses and minor lesions, as many authors
have suggested [26]. Evaluating risk factors for plantar ulcers is an important factor, and
further research in diabetic foot surgery should address this. Finally, floating toes were
found in 80% of the subgroup of patients who underwent several tenotomies. Despite this,
the patients did not develop any complications secondary to the hyperextension of the toe,
and only one patient developed a distal ulcer secondary to a small shoe size that healed
within the standard of care [28].
The present study includes the highest yet published sample of patients with flexor
tenotomies on a prophylactic basis and a prospective design. This is the first study also, that
analyzes clinical outcomes after flexor tenotomies divided by the number of tenotomies
performed. Further research should focus on controlled studies, and additionally, the costeffectiveness of the procedure should be investigated in comparison with other noninvasive
interventions.
However, our results should be interpreted with caution because we only evaluated
patients without ischemia, and patients with a poor vascular supply could benefit from
this simple and non-aggressive procedure. Additionally, further research should confirm
the effectiveness of percutaneous flexor tenotomies with alternative procedures such as
toe orthosis and footwear modifications. Unfortunately, the sample size was reduced
in number than originally calculated, due to the difficulty in recruiting patients and the
difficulty in finding the requirement in characteristic needed.
5. Conclusions
Patients who underwent several tenotomies had better clinical outcomes after a 1-year
follow-up period compared to isolated tenotomies. To reduce complications, clinicians
should consider performing several tenotomies in patients with toe ulcers.
Author Contributions: Conceptualization, M.L.-M., R.J.M.-B. and J.L.L.-M.; methodology, M.L.-M.,
R.J.M.-B. and J.L.L.-M.; software, M.L.-M., Y.G.-Á., I.S.-C. and A.T.-G.; validation, M.L.-M., Y.G.-Á.
and J.L.L.-M.; formal analysis, M.L.-M., R.J.M.-B. and J.L.L.-M.; investigation, M.L.-M., Y.G.-Á.,
I.S.-C., A.T.-G.; resources, M.L.-M., R.J.M.-B. and J.L.L.-M.; data curation, M.L.-M., I.S.-C. and A.T.G.; writing—original draft preparation, M.L.-M.; writing—review and editing, M.L.-M., R.J.M.-B.
and J.L.L.-M.; visualization, M.L.-M. and J.L.L.-M.; supervision, R.J.M.-B. and J.L.L.-M.; project
administration, M.L.-M., R.J.M.-B. and J.L.L.-M. All authors have read and agreed to the published
version of the manuscript.
Funding: This research received no external funding.
Institutional Review Board Statement: The study was conducted in accordance with the Declaration
of Helsinki, and approved by the Institutional Review Board of Instituto de Investigación Sanitara
Hospital Clínico San Carlos (19/173-E on May 2019).
Informed Consent Statement: Informed consent was obtained from all subjects involved in the
study. Written informed consent has been obtained from the patient(s) to publish this paper.
Data Availability Statement: Not applicable.
Acknowledgments: The authors gratefully acknowledge the support of the staff and patients of the
Diabetic Foot Unit of the Complutense University of Madrid.
Conflicts of Interest: The authors declare no conflict of interest.
J. Clin. Med. 2022, 11, 4093
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References
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
12.
13.
14.
15.
16.
17.
18.
19.
20.
21.
22.
23.
24.
25.
Gershater, M.A.; Londahl, M.; Nyberg, P.; Larsson, J.; Thorne, J.; Eneroth, M.; Apelqvist, J. Complexity of factors related to
outcome of neuropathic and neuroischaemic/ischaemic diabetic foot ulcers: A cohort study. Diabetologia 2009, 52, 398–407.
[CrossRef]
Ince, P.; Kendrick, D.; Game, F.; Jeffcoate, W. The association between baseline characteristics and the outcome of foot lesions in a
UK population with diabetes. Diabet. Med. 2007, 24, 977–981.
Pickwell, K.M.; Siersma, V.D.; Kars, M.; Holstein, P.E.; Schaper, N.C. Eurodiale c. Diabetic foot disease: Impact of ulcer location
on ulcer healing. Diabetes Metab. Res. Rev. 2013, 29, 377–383. [CrossRef] [PubMed]
Malhotra, K.; Davda, K.; Singh, D. The pathology and management of lesser toe deformities. EFORT Open Rev. 2016, 1, 409–419.
[PubMed]
Cowley, M.S.; Boyko, E.J.; Shofer, J.B.; Ahroni, J.H.; Ledoux, W.R. Foot ulcer risk and location in relation to prospective clinical
assessment of foot shape and mobility among persons with diabetes. Diabetes Res. Clin. Pract. 2008, 82, 226–232. [PubMed]
La Fontaine, J.; Lavery, L.A.; Hunt, N.A.; Murdoch, D.P. The role of surgical off-loading to prevent recurrent ulcerations. Int. J.
Low Extrem. Wounds 2014, 13, 320–334. [CrossRef]
Bus, S.A.; Valk, G.D.; Van Deursen, R.W.; Armstrong, D.G.; Caravaggi, C.; Hlaváček, P.; Bakker, K.; Cavanagh, P.R. The
effectiveness of footwear and off-loading interventions to prevent and heal foot ulcers and reduce plantar pressure in diabetes: A
systematic review. Diabetes Metab. Res. Rev. 2008, 24 (Suppl. 1), S162–S180.
Bonanno, D.R.; Gillies, E.J. Flexor Tenotomy Improves Healing and Prevention of Diabetes-Related Toe Ulcers: A Systematic
Review. J. Foot Ankle Surg. 2017, 56, 600–604. [CrossRef]
Bus, S.A.; Lavery, L.A.; Monteiro-Soares, M.; Rasmussen, A.; Raspovic, A.; Sacco, I.C.; van Netten, J.J. Guidelines on the prevention
of foot ulcers in persons with diabetes (IWGDF 2019 update). Diabetes Metab. Res. Rev. 2020, 36 (Suppl. 1), e3269. [CrossRef]
Kearney, T.P.; Hunt, N.A.; Lavery, L.A. Safety and effectiveness of flexor tenotomies to heal toe ulcers in persons with diabetes.
Diabetes Res. Clin. Pract. 2010, 89, 224–226. [CrossRef]
Van Netten, J.J.; Bril, A.; van Baal, J.G. The effect of flexor tenotomy on healing and prevention of neuropathic diabetic foot ulcers
on the distal end of the toe. J. Foot Ankle Res. 2013, 6, 3. [CrossRef] [PubMed]
Rasmussen, A.; Bjerre-Christensen, U.; Almdal, T.P.; Holstein, P. Percutaneous flexor tenotomy for preventing and treating toe
ulcers in people with diabetes mellitus. J. Tissue Viability 2013, 22, 68–73. [PubMed]
Scott, J.E.; Hendry, G.J.; Locke, J. Effectiveness of percutaneous flexor tenotomies for the management and prevention of recurrence
of diabetic toe ulcers: A systematic review. J. Foot Ankle Res. 2016, 9, 25. [CrossRef] [PubMed]
Lazaro-Martinez, J.L.; Garcia-Madrid, M.; Garcia-Alvarez, Y.; Alvaro-Afonso, F.J.; Sanz-Corbalan, I.; Garcia-Morales, E. Conservative surgery for chronic diabetic foot osteomyelitis: Procedures and recommendations. J. Clin. Orthop. Trauma 2021, 16, 86–98.
[PubMed]
Tamir, E.; McLaren, A.M.; Gadgil, A.; Daniels, T.R. Outpatient percutaneous flexor tenotomies for management of diabetic claw
toe deformities with ulcers: A preliminary report. Can. J. Surg. 2008, 51, 41–44. [PubMed]
Schaper, N.C.; Andros, G.; Apelqvist, J.; Bakker, K.; Lammer, J.; Lepantalo, M.; Mills, J.L.; Reekers, J.; Shearman, C.P.; Zierler,
R.E.; et al. Diagnosis and treatment of peripheral arterial disease in diabetic patients with a foot ulcer. A progress report of the
International Working Group on the Diabetic Foot. Diabetes Metab. Res. Rev. 2012, 28 (Suppl. 1), 218–224.
World Medical Association. World Medical Association Declaration of Helsinki: Ethical principles for medical research involving
human subjects. JAMA 2013, 310, 2191–2194. [CrossRef] [PubMed]
Schaper, N.C.; van Netten, J.J.; Apelqvist, J.; Bus, S.A.; Hinchliffe, R.J.; Lipsky, B.A.; IWGDF Editorial Board. Practical Guidelines on the prevention and management of diabetic foot disease (IWGDF 2019 update). Diabetes Metab. Res. Rev. 2020, 36
(Suppl. 1), e3266. [CrossRef]
Hinchliffe, R.J.; Forsythe, R.O.; Apelqvist, J.; Boyko, E.J.; Fitridge, R.; Hong, J.P.; Katsanos, K.; Mills, J.L.; Nikol, S.; Reekers, J.;
et al. Guidelines on diagnosis, prognosis, and management of peripheral artery disease in patients with foot ulcers and diabetes
(IWGDF 2019 update). Diabetes Metab. Res. Rev. 2020, 36 (Suppl. 1), e3276. [CrossRef]
Muscarella, V.; Sadri, S.; Pusateri, J. Indications and considerations of foot and ankle arthrodesis. Clin. Podiatr. Med. Surg. 2012,
29, 1–9. [CrossRef] [PubMed]
Sanz-Corbalan, I.; Lazaro-Martinez, J.L.; Garcia-Alvarez, Y.; Garcia-Morales, E.; Alvaro-Afonso, F.; Molines-Barroso, R. Digital
Deformity Assessment Prior to Percutaneous Flexor Tenotomy for Managing Diabetic Foot Ulcers on the Toes. J. Foot Ankle Surg.
2019, 58, 453–457. [CrossRef] [PubMed]
Armstrong, D.G.; Lavery, L.A.; Frykberg, R.G.; Wu, S.C.; Boulton, A.J. Validation of a diabetic foot surgery classification. Int.
Wound J. 2006, 3, 240–246. [PubMed]
Lopez-Moral, M.; Lazaro-Martinez, J.L.; Garcia-Morales, E.; Garcia-Alvarez, Y.; Alvaro-Afonso, F.J.; Molines-Barroso, R.J. Clinical
efficacy of therapeutic footwear with a rigid rocker sole in the prevention of recurrence in patients with diabetes mellitus and
diabetic polineuropathy: A randomized clinical trial. PLoS ONE 2019, 14, e0219537. [CrossRef] [PubMed]
Bus, S.A.; de Lange, A. A comparison of the 1-step, 2-step, and 3-step protocols for obtaining barefoot plantar pressure data in the
diabetic neuropathic foot. Clin. Biomech. 2005, 20, 892–899.
van Netten, J.J.; Bus, S.A.; Apelqvist, J.; Lipsky, B.A.; Hinchliffe, R.J.; Game, F.; Rayman, G.; Lazzarini, P.A.; Forsythe, R.O.; Peters,
E.J.G.; et al. Definitions and criteria for diabetic foot disease. Diabetes Metab. Res Rev. 2020, 36 (Suppl. 1), e3268. [CrossRef]
J. Clin. Med. 2022, 11, 4093
26.
27.
28.
10 of 10
Waaijman, R.; De Haart, M.; Arts, M.L.; Wever, D.; Verlouw, A.J.; Nollet, F.; Bus, S.A. Risk factors for plantar foot ulcer recurrence
in neuropathic diabetic patients. Diabetes Care 2014, 37, 1697–1705. [CrossRef]
Lazaro-Martinez, J.L.; Aragon-Sanchez, F.J.; Beneit-Montesinos, J.V.; Gonzalez-Jurado, M.A.; Garcia Morales, E.; Martinez
Hernandez, D. Foot biomechanics in patients with diabetes mellitus: Doubts regarding the relationship between neuropathy, foot
motion, and deformities. J. Am. Podiatr. Med. Assoc. 2011, 101, 208–214. [CrossRef]
Rayman, G.; Vas, P.; Dhatariya, K.; Driver, V.; Hartemann, A.; Londahl, M.; Piaggesi, A.; Apelqvist, J.; Attinger, C.; Game, F.; et al.
Guidelines on use of interventions to enhance healing of chronic foot ulcers in diabetes (IWGDF 2019 update). Diabetes Metab.
Res. Rev. 2020, 36 (Suppl. 1), e3283. [CrossRef]