Content uploaded by Taner Karlidag
Author content
All content in this area was uploaded by Taner Karlidag on Jun 21, 2024
Content may be subject to copyright.
Received: 24 December 2023
|
Accepted: 12 March 2024
DOI: 10.1002/ksa.12163
ANKLE
Effects of tendon elongation on plantar pressure and
clinical outcomes: A comparative analysis between open
repair and minimally invasive surgery
Taner Karlidag
1,2
|Olgun Bingol
2
|Burak Kulakoglu
2
|Omer Halit Keskin
2
|
Atahan Durgal
2
|Guzelali Ozdemir
2
1
Department of Orthopedics and
Traumatology Surgery, Helios ENDO‐Klinik,
Hamburg, Germany
2
Department of Orthopedics and
Traumatology, Ankara Bilkent City Hospital,
Ankara, Turkey
Correspondence
Taner Karlidag, Department of Orthopedics
and Traumatology, Helios ENDO‐Klinik,
Hamburg, Germany.
Email: dr.tanerkarlidag@gmail.com
Funding information
None
Abstract
Purpose: The aim of this study was to assess whether variances in Achilles
tendon elongation are linked to dissimilarities in the plantar pressure distribution
following two different surgical approaches for an Achilles tendon rupture (ATR).
Methods: All patients who were treated with open or minimally invasive
surgical repair (MIS) and were over 2 years post their ATR were eligible for
inclusion. A total of 65 patients with an average age of 43 ± 11 years were
included in the study. Thirty‐five patients were treated with open repair, and
30 patients were treated with MIS. Clinical outcomes were evaluated using
the American Orthopedic Foot and Ankle Society (AOFAS) and ATR Score
(ATRS). Achilles tendon elongation was measured using axial and sagittal
magnetic resonance imaging scans. Plantar pressure measurements for the
forefoot, midfoot and hindfoot during gait were divided into percentages
based on total pressure, measured in g/cm
2
for each area.
Results: The average AOFAS score was found ‘excellent’(93 ± 2.8) in the MIS
group, while it was found ‘good’(87.4 ± 5.6) in the open repair group. In addition,
the MIS group showed significantly superior ATRS scores (78.8 ± 7.4) compared
to the open repair group (56.4 ± 15.4) (p< 0.001). The average tendon
elongation in the MIS group was 11.3 ± 2 mm, while it was 17.3 ± 4.3 mm (p<
0.001) in the open repair group. While the open repair group showed significantly
higher plantar pressure distribution in the initial contact and preswing phases
compared to uninjured extremities, there was no significant difference between
the uninjured extremities and the MIS group.
Conclusion: In conclusion, the findings of this study demonstrated that
minimally invasive surgery was associated with less tendon elongation,
more proximity to the plantar pressure distributions of the uninjured
extremity and superior clinical outcomes compared to open surgical repair.
Therefore, minimally invasive surgery may be considered a more suitable
option for acute Achilles tendon repair to achieve overall better outcomes.
Level of Evidence: Level III.
KEYWORDS
Achilles tendon rupture, ankle kinematics, gait analysis, minimally invasive approach, plantar
pressure distribution, push‐offmechanism
Knee Surg Sports Traumatol Arthrosc. 2024;32:1880–1890.1880
|
wileyonlinelibrary.com/journal/ksa
© 2024 European Society of Sports Traumatology, Knee Surgery and Arthroscopy.
Abbreviations: AATR, acute Achilles tendon rupture; AOFAS, American Orthopedic Foot and Ankle Society; ATRS, Achilles Tendon Total Rupture Score; BMI, body mass
index; MRI, magnetic resonance imaging; PROMs, Patient‐Related Outcome Measures; STROBE, Strengthening the Reporting of Observational Studies in Epidemiology.
INTRODUCTION
The Achilles tendon is the most commonly ruptured
tendon in the human body, and the incidence of acute
rupture is rising [33]. This common injury causes
substantial morbidity, especially in young and active
patients [33]. Although there is controversy over the
standard care for Achilles tendon rupture (ATR),
surgical repair is valuable due to its faster return to
sport rate, greater strength and reduced rerupture rates
compared to nonoperative treatment.
The triceps surae is active from the mid‐stance phase
through the beginning of the preswing phase in normal
walking and provides most of the mechanical strength
required for forward propulsion during the pushing stage of
gait [6, 12]. Tendon elongation after ATR has been
highlighted as a major problem that leads to decreased
single heel raise height, triceps surae weakness and
reduced plantar flexor power and push‐offforce during
heel lift [9, 16, 28, 39]. A recent cohort study found that
adults with longer gastrocnemius fascicles generate
greater plantar flexor work and power [7]. Patients
increase work done by the knee joint to compensate for
reduced plantar flexor function during gait [37]. These
findings consistently show that an elongation following
ATR can significantly impact skeletal muscle function,
resulting in long‐term functional deficits. Furthermore,
previous studies have revealed that the clinical outcome
is significantly correlated with the elongation of the Achilles
tendon, with better outcome scores observed when less
elongation occurred [30, 32, 39].
It is essential to comprehend the underlying causes
of shortcomings since this can impact the type and
timing of intervention required to yield favourable
outcomes. The aim of this study was to determine
whether dissimilarities in plantar pressure distribution
following two different surgical approaches for an ATR
are linked to variances in Achilles tendon elongation. To
our knowledge, there is no study that conclusively
compares these surgical approaches using plantar
pressure mapping and delivers quantitative values. We
hypothesised that open repair would have a more
detrimental effect on the tendon elongation due to
extensive tissue dissection and degradation of the
paratenon, which could result in an imbalanced plantar
pressure distribution compared to uninjured extremity.
MATERIALS AND METHODS
The study was authorised by the local ethics committee
(University of Health Science, Ankara Bilkent City
Hospital, E1‐22‐2557) and carried out in compliance
with the ethical standards of the Declaration of Helsinki.
Before participation, patients provided written informed
consent. We retrospectively analysed all patients in our
database who had acute ATR and were treated
surgically in our centre between January 2019 and
April 2021. This study was reported according to the
Strengthening the Reporting of Observational Studies
in Epidemiology (STROBE) guidelines [10].
Inclusion and exclusion criteria
All patients who were treated with open or minimally
invasive surgical repair (MIS) and were over 2 years post
their ATR were eligible for inclusion. This time period is
based on literature that suggests functional gains are
mostly achieved within the first year following an injury,
with limited additional gains between 1 and 2 years
postinjury and beyond 7 years postinjury [4, 29]. The
exclusion criteria applied: (1) chronic ruptures (>10 days),
(2) <18 years of age, (3) patients with proximal or
insertional ruptures, (4) history of postoperative complica-
tions including deep vein thrombosis or rerupture and (5)
history of previous surgery on the same or uninjured
extremity (Figure 1).
Description of the cohort
All ruptures were diagnosed preoperatively based on a
palpable defect at the rupture site, a positive Thompson
test and ultrasonographic verification. Thirty‐five pa-
tients were treated with open repair, and 30 patients
were treated with minimally invasive repair. The same
surgeon (senior author) treated and operated on all
patients. Since our institution is a training hospital, both
surgical approaches are applied for resident training
regardless of specific indications, as long as they fall
within the scope of inclusion criteria.
Surgical procedures
Open surgical technique
The open repair involved administering spinal or general
anaesthesia, placing the patient prone and using a single
preoperative dose of 2 g cefazolin intravenously. A poster-
omedial incision was made over the defect, with routine
tourniquet use. Proximal and distal tendon edges were
dissected and debrided, and the repair utilised the
Krackow method with nonabsorbable No. 2 Ethibond.
The periphery was braided with 2/0 absorbable sutures
(Vicryl), repairing the paratenon. Vicryl sutures closed the
subcutaneous tissue, while nylon sutures closed the skin.
Minimally invasive surgical technique
The minimally invasive repair followed the same
preoperative protocol, including tourniquet use. A
MIS AND TENDON ELONGATION
|
1881
2‐cm horizontal skin incision at the palpable gap
allowed clear exposure of the proximal and distal
tendon stumps while preserving the sural nerve.
Oval forceps were inserted through the incision,
positioned deep to the paratenon, in the longitudinal
axis of the tendon. A puncture needle, using
nonabsorbable No. 2 Ethibond, passed through the
lateral and medial skin, the respective holes of the
ovarian clamp and the Achilles tendon. Six non-
absorbable sutures were passed from proximal to
distal in the tendon, paired and tied accordingly. The
paratenon was repaired with Vicryl sutures, and
closure involved Vicryl for subcutaneous tissue and
nylonfortheskin(Figure2).
Rehabilitation protocol
All patients underwent a standardised postoperative
rehabilitation protocol and received regular follow‐ups
at the outpatient clinic in accordance with our clinical
approach. Postoperatively, a nonweight‐bearing equi-
nus cast was applied for 2 weeks, followed by the use
of a controlled ankle movement walker orthosis
(VACOped; OPED), locked at 20° equinus, worn day
and night. Standard rehabilitation was initiated with
gradual equinus reduction to neutral over 6 weeks.
Weight‐bearing progressed from partial to full at
6 weeks based on patient tolerance and achieved full
range of motion. The walking boot was removed
FIGURE 1 Study design. This flowchart depicts patient acquisition in the current study and the number of exclusions as well as the pathway
of examinations and analyses.
1882
|
MIS AND TENDON ELONGATION
between 6 and 8 weeks, and formal physiotherapy
rehabilitation was continued.
Data collection
Patients over 24 months of follow‐up were contacted
via telephone and called back to the hospital. All
patients consented to their outcome data being
included in the study. Age, sex, operation side, duration
of follow‐ups, body mass index (BMI), nicotine
abuse and times of return to work were collected and
recorded.
Clinical outcome evaluation
Clinical outcomes were evaluated using the American
Orthopedic Foot and Ankle Society (AOFAS)
ankle–hindfoot functional score and Achilles Tendon
Total Rupture Score (ATRS). An AOFAS score of
90–100 is expressed as excellent, 80–89 as good,
70–79 as fair and <69 as poor [19]. The ATRS is a
patient‐reported instrument for measuring the outcome
related to symptoms and physical activity after
treatment in patients with a total ATR [27]. To prevent
potential bias, all of the clinical and functional evalua-
tions in this study were assessed by an independent
research assistant who was not part of the operative or
research team.
Magnetic resonance imaging assessments
The study measured the length of the Achilles tendon
in both the operated and uninjured leg using axial and
sagittal magnetic resonance imaging (MRI) scans
taken at least 24 months after the injury. The length
of the Achilles tendon was determined using a similar
method developed by Heikkinen et al. [14] measuring
the distance from the most distal part of the soleus
muscle to the calcaneal insertion of the Achilles tendon.
This point was defined as the spot where the axial
plane intersects with the most cranial aspect of the
tuber calcanei. T1 weighted slices were used for all
measurements. Measurements were performed as
follows: the myotendinous junction (MTJ) of the soleus
was identified on axial slices and the intersection of this
exact point on the sagittal slices was obtained. After
that, the distance from this level to the calcaneal
insertion was measured on sagittal slices (Figure 3).
This method was first described by Silbernagel et al.
[35] for ultrasound (US). A similar technique that
involved measuring the distance between the calca-
neus and the medial gastrocnemius MTJ was validated
by Barfod et al. [1].
The open and minimally invasive repair groups
were carefully evaluated to measure the difference in
length between the operated and uninjured extremities.
An independent radiologist, who was not aware of the
treatment groups, repeated the MRI measurements of
each patient three times. The tendon lengths were
recorded as the average value of all measurements.
Gait analysis and plantar pressure mapping
Expert orthotic and prosthetic technicians conducted
plantar pressure mapping analysis using a pedobaro-
graphic system with static and dynamic capabilities on
a Tartan track (3M). Pedobarographic static measure-
ments were obtained using a 2‐m Footscan printing
plate device (RSscan International), which has been
validated for assessing plantar pressure mapping in
previous research [3]. Patients were tested barefoot,
and before each session, the pressure mat was
calibrated based on the patient's height, weight and
foot size.
The foot's sole was divided into 15 areas corre-
sponding to different regions supporting body weight:
heel (areas 1–3), midfoot (areas 4–5), metatarsal
(areas 6–10) and toe (areas 11–15) (Figure 4)[34].
FIGURE 2 Schematic representation of the horizontal incision
(shown in red) and six sutures, three proximal and three distal, in a
minimally invasive surgical technique.
MIS AND TENDON ELONGATION
|
1883
FIGURE 3 (a) Determining the anteromedial joint line of the tibia and measuring distal 15 cm. (b) Measuring the maximum calf
circumference from the determined line.
FIGURE 4 The sole of the foot is divided into 15 areas, which
support most of the body weight and are adjusted by the body's
balance: heel (area 1–3), midfoot (area 4–5), metatarsal (area 6–
10) and toe (area 11–15).
Pressure on the heel indicated initial contact at the
hindfoot, midfoot pressure represented mid‐stance and
pressure on the metatarsal and toe regions reflected
preswing (push‐off) during gait analysis. Plantar pres-
sure measurements for the forefoot, midfoot and hind-
foot were expressed as percentages of total pressure,
measured in g/cm
2
for each area. Patient‐specific
natural plantar pressure distribution during gait, based
on uninjured extremities, served as the reference.
Patients walked on the platform at their average
daily pace, completing at least six successful walking
attempts. Data recorded by averaging the tests
performed documented plantar pressure distribution
during initial contact, mid‐stance and preswing gait
phases in the operated extremity, which were then
compared to the uninjured extremity (Figure 5). Surgi-
cal approach differences were also noted.
Statistical analysis
A post hoc power analysis was conducted using
G*Power version 3.1.9.4 to determine the power of
the study's participant count. The results indicated that
the study was 99% powerful with an a= 0.05. Statistical
analysis was performed using the SPSS version 22.0
software program for Windows. Descriptive statistics
frequency, percentage, mean, standard deviation,
median and minimum–maximum expressed as values.
Since the quantitative data, except mid‐stance, did not
show the normal distribution in the Shapiro–Wilk test,
nonparametric test procedures were used. In this
context, the Mann–Whitney U‐test was used to deter-
mine the relationships between parameters.
Independent‐sample t‐test was used in the analysis of
mid‐stance phase data. The χ
2
test was used in the
analysis of categorical data. The results were evaluated
1884
|
MIS AND TENDON ELONGATION
within the 95% confidence interval, and p< 0.05 value
was considered significant.
RESULTS
All 65 patients who remained—57 males and
eight females with an average age of 43 ± 11 years
(range: 20–70 years)—were included in the study. The
average follow‐up time was 29.8 ± 10 months
(range: 24–41 months). The mean and interval range
of demographic data of the patients in this cohort were
provided in Table 1. There was no significant difference
in age, sex, operation side, duration of follow‐ups,
BMI and smoking status for both groups.
Table 2represents the precise values for AOFAS
and ATRS scores, the amount of tendon elongations in
MRI and the time of return to work of the patients. The
mean AOFAS score for open repair is categorised as
‘good’(87.4), while the minimally invasive repair is
unequivocally considered ‘excellent’(93). The AOFAS
and ATRS scores were significantly superior in patients
with the minimally invasive repair group. However, the
time of return to work was significantly less in the
minimally invasive surgery group (p< 0.001). In addi-
tion, tendon elongation compared to uninjured extre-
mity was significantly higher in patients with open repair
(p< 0.001).
The percentages of plantar pressure distribution
during preswing, mid‐stance and initial contact phases
for the operated and uninjured extremities are dis-
played in Table 3. The initial contact and preswing
phases were significantly higher in the operated
extremities. While extremities treated with open
surgical repair showed significantly higher plantar
pressure distribution in the initial contact and preswing
phases compared to uninjured extremities, there was
no significant difference between uninjured extremities
and the MIS group (Table 4). However, there was no
statistically significant difference between surgical
approaches regarding plantar pressure distributions
(Table 5).
DISCUSSION
The most important finding of this study was that
patients who underwent minimally invasive treatment
for their acute ATR experienced an average of 6 mm
less tendon elongation. In addition, they also showed
significant improvement in the distribution of plantar
pressure, closely resembling the uninjured extremity.
Clinical and functional deficits are known problems
after AATR, regardless of treatment method [23, 29,
31]. The reasons for these deficits need to be clarified.
Still, it is well known that these deficits may lead to
severe limitations in daily life and an inability to return
to preinjury activity levels [15, 23, 36]. Significant
deficits in function persist 2 years after injury regardless
of surgical or nonsurgical treatment [29].
Although surgical repair of the Achilles tendon is
intended to restore its full function, a significant
elongation in the tendon still occurs. Several studies
confirmed this finding after open and minimally invasive
repair [15]. Gastrocnemius muscle undergoes remo-
delling after the ATRs, likely due to the sudden loss of
muscle–tendon tension [17]. Paratenon plays a vital
role in tendon healing, regulating growth factors and
FIGURE 5 An example of a patient's foot pressure mapping.
MIS AND TENDON ELONGATION
|
1885
proteins essential for collagen synthesis and stimulat-
ing recovery of mechanical strength [8, 21, 25]. A
recent animal study showed that the absence of the
paratenon results in delayed formation of the tendon
callus, decreased blood supply and a biomechanically
weaker tendon [26]. It has been stated that even long
incisions applied in open repair may impair tendon
healing by decreasing blood supply [38]. An increase in
the length of the tendon following acute ATR can affect
various factors, including reduced tendon tension and
heel‐rise height, increased pennation angle, shorter
fascicle length and weakness in plantar flexor power
and pushoffmechanism [2, 9, 16, 17, 28]. Previous
studies have investigated the impact of these structural
alterations on subjective PROMs (Patient‐Related
Outcome Measures) and objective outcomes (gait
analysis) [16, 18, 36]. Carmont et al. [5] suggested
TAB L E 1 Demographic data on patients with open repair and MIS:
age, BMI, duration of follow‐ups, sex, operation side and smoking status.
Mean SD Minimum Maximum pValue*
Age
Open (n= 35) 41 11.8 20 61 n.s.
MIS (n= 30) 45.4 10.9 24 70
BMI (kg/m
2
)
Open (n= 35) 29.8 6.2 17.4 48.8 n.s.
MIS (n= 30) 28 4.1 20 42
Follow‐up (month)
Open (n= 35) 30.6 9.4 24 41 n.s.
MIS (n= 30) 28.9 10.7 24 40
Number Percent (%) pValue*
Sex
Open
Male 28 80 n.s.
Female 7 20
Total 35 100
MIS
Male 29 96.7
Female 1 3.3
Total 30 100
Operation side
Open
Right 25 71.4 n.s.
Left 10 28.6
Total 35 100
MIS
Right 17 56.7
Left 13 43.3
Total 30 100
Smoking status (yes/no)
Open
Yes 15 42.9 n.s.
No 20 57.1
Total 35 100
MIS
Yes 16 53.3
No 14 46.7
Total 30 100
Abbreviations: BMI, body mass index; MIS, minimally invasive surgery repair;
n.s., not significant; SD, standard deviation
*p< 0.05 was considered statistically significant.
TABLE 2 AOFAS score, ATRS, tendon elongation in MRI, time
of return to work and complication rates of patients with open repair
and MIS.
Mean SD Minimum Maximum pVal ue*
AOFAS
Open (n= 35) 87.4 5.6 80 95 <0.001*
MIS (n= 30) 93 2.8 85 95
ATRS
Open (n= 35) 56.4 15.4 21 88 <0.001*
MIS (n= 30) 78.8 7.4 54 90
Tendon elongation (mm)
Open (n= 35) 17.3 4.3 10.4 26.2 <0.001*
MIS (n= 30) 11.3 2.0 5.6 16.9
Time of return to work (months)
Open (n= 35) 4.6 1.6 1 7 <0.001*
MIS (n= 30) 2.9 1.0 1 5
Number Percent (%) pValue*
Complication
Open
Yes 4 11.4 n.s.
No 31 88.5
Total 35 100
MIS
Yes 3 10
No 27 90
Total 30 100
Abbreviations: AOFAS, American Orthopaedic Foot and Ankle Society;
ATRS, Achilles Tendon Total Rupture Score; MIS, minimally invasive surgery repair;
MRI, magnetic resonance imaging; n.s., not significant; SD, standard deviation.
*p< 0.05 was considered statistically significant.
1886
|
MIS AND TENDON ELONGATION
that the Achilles Tendon Resting Angle (ATRA) can be
indirectly used to assess the length of the Achilles
tendon. Contrary to Larsson et al. [20], Carmont et al.
[5] found a strong correlation between ATRA and ATRS
after surgery. In addition, it has been reported that after
ATR, differential elongation of the gastrocnemius
relative to the soleus may compromise the ability of
athletes to return to competition [16]. Interestingly,
28%–39% of National Basketball Association players
and 18%–22% of soccer players are unable to play
again due to this issue [11, 13, 24]. However, studies
have yet to compare surgical methods to determine the
most effective technique for avoiding these changes
and achieving natural plantar pressure distributions.
Significant elongation of the Achilles tendon and
inferior clinical outcomes such as AOFAS and ATRS
scores were found in patients with open repair. Our
substantial reduction in PROMs with significant tendon
lengthening was consistent with findings in various
studies [15, 36]. Heikkinen et al. [15] reported that
Achilles tendon lengthening correlated with the ankle
end‐range plantar flexion strength deficit and soleus
and medial gastrocnemius muscle volume deficits.
They revealed 11%–13% deficits in soleus and
gastrocnemius muscle volumes and 12%–18% deficits
in plantar flexion strength persist even after long‐term
follow‐up [15]. As we mentioned above, we believe that
this significant difference between the two groups
regarding PROMs was due to an increase in tendon
length and weakness in plantar flexor power and
pushoffmechanism.
The study found a significant increase in the
forefoot and hindfoot pressure compared to uninjured
extremities in the preswing and initial contact phase
TAB L E 3 Comparison of plantar pressure distribution during gait analysis between the operated and uninjured extremities.
Mean SD Minimum Maximum pValue*
Plantar pressure distribution percentage during initial contact phase (%)
Operated (n= 65) 56.2 7.3 44.4 80 0.005*
Uninjured (n= 65) 52.9 7.7 39.7 74.4
Plantar pressure distribution percentage during mid‐stance phase (%)
Operated (n= 65) 50.6 5.2 38.5 63.5 n.s.
Uninjured (n= 65) 49.6 5 36.5 61.5
Plantar pressure distribution percentage during preswing (push‐off) phase (%)
Operated (n= 65) 43.7 7.3 20 55.6 0.005*
Uninjured (n= 65) 47 7.7 25.6 60.3
Abbreviations: n.s., not significant; SD, standard deviation.
*p< 0.05 was considered statistically significant.
TABLE 4 Separate comparison of plantar pressure distribution
during gait analysis between the uninjured extremities and both
surgical approaches.
Mean SD Minimum Maximum pVal ue*
Plantar pressure distribution percentage during initial contact phase (%)
Open (n= 35) 56.8 7.4 44.4 73.8 0.009*
Uninjured
(n= 65)
52.9 7.7 39.7 74.4
MIS (n= 30) 55.5 7.2 47.4 80 n.s.
Uninjured
(n= 65)
52.9 7.7 39.7 74.4
Plantar pressure distribution percentage during mid‐stance phase (%)
Open (n= 35) 49.7 4.8 42.1 63.5 n.s.
Uninjured
(n= 65)
49.6 5 36.5 61.5
MIS (n= 30) 51.7 5.4 38.5 60.9 n.s.
Uninjured
(n= 65)
49.6 5 36.5 61.5
Plantar pressure distribution percentage during preswing (push‐off)
phase (%)
Open (n= 35) 43.1 7.4 26.2 55.6 0.009*
Uninjured
(n= 65)
47 7.7 25.6 60.3
MIS (n= 30) 44.4 7.2 20 52.6 n.s.
Uninjured
(n= 65)
47 7.7 25.6 60.3
Abbreviations: MIS, minimally invasive surgery repair; n.s., not significant;
SD, standard deviation.
*p< 0.05 was considered statistically significant.
MIS AND TENDON ELONGATION
|
1887
during gait in patients with open repair. However, the
patients with minimally invasive repair showed more
proximity with uninjured extremities' plantar pressure
distribution. We expected but did not find any decrease
in forefoot peak pressure like the previous research
about tendon elongation in treating foot ulcers by Maluf
et al. [22]. Notwithstanding, they disclosed that the
reduction in pressure on the forefoot was temporary
[22]. In contrast, a recent randomised controlled trial
conducted on a nonsurgically treated Achilles tendon
revealed a 1.7 cm elongation, which did not signifi-
cantly influence foot loading during walking gait when
compared to the uninjured extremity [18]. A positive
correlation between substantial lengthening of tendons
and disruption in plantar pressure distribution was
determined. However, since considerable tendon elon-
gation was detected in both surgical approaches
compared to the uninjured extremity, this finding cannot
be the only explanation for the deterioration in plantar
pressure distribution. As mentioned above, alterations
in muscle configuration and skeletal function or even
tissue dissection following different surgical repairs of
ATR may lead to this difference in plantar pressure
distribution. Hence, we recommend that forthcoming
studies concentrate on examining how changes in
muscle structure impact the distribution of pressure on
the foot. This will allow for a better understanding of the
connection between muscle remodelling and shifts in
plantar pressure.
This study is not without limitations, and our
findings should be interpreted in light of these
issues. First, it should be noted that our research
was retrospective in nature, and further validation
through randomised controlled trials is necessary to
verify the results. Although our study population is
highly selective, and this minimises relevant biases,
the nature of the retrospective design brings along
bias in patient selection. Second, this study used the
uninjured side as a within‐subject control. An
uninjured control group was not included to limit
variables that could confound the analysis (i.e.,
physical activity level, body mass index, age, etc.).
Furthermore, a comparison between the recovery of
tendons in situations where a surgical approach was
implemented and those in which it was not could not
be made by our research. Individuals in this study
could have modified their plantar pressure distribu-
tions bilaterally in response to their Achilles rupture,
reducing the effect of the presence of rupture in this
analysis. The other limitation of this study was that
we could not use more sophisticated gait and plantar
pressure distribution systems (i.e., in‐shoe plantar
pressure systems or wireless applications). Although
previous studies demonstrated no significant differ-
ence in Achilles tendon strength between different
surgical techniques, biomechanical tests, including
isokinetic contraction strength tests, were not per-
formed to confirm the patients' Achilles tendon
strength objectively. Last, the measurement of
Achilles tendon length through our method, which
is based on the soleus MTJ, has not yet been
validated for MRI. Nevertheless, Silbernagel et al.
[35] have recently described its validation for US,
andBarfodetal.[1] have also validated a similar
technique. Therefore, we contend that measuring
Achilles tendon length through the soleus MTJ, as
done in our method, is also a valid and reliable
approach.
CONCLUSION
In conclusion, the findings of this study demonstrated that
the minimally invasive surgery was associated with less
tendon elongation, more proximity to the plantar pressure
distributions of the uninjured extremity and superior clinical
TAB L E 5 Comparison of plantar pressure distribution during gait analysis between the open repair and MIS groups.
Mean SD Minimum Maximum pValue*
Plantar pressure distribution percentage during initial contact phase (%)
Open (n= 35) 56.8 7.4 44.4 73.8 n.s.
MIS (n= 30) 55.5 7.2 47.4 80
Plantar pressure distribution percentage during mid‐stance phase (%)
Open (n= 35) 49.7 4.8 42.1 63.5 n.s.
MIS (n= 30) 51.7 5.4 38.5 60.9
Plantar pressure distribution percentage during preswing (push‐off) phase (%)
Open (n= 35) 43.1 7.4 26.2 55.6 n.s.
MIS (n= 30) 44.4 7.2 20 52.6
Abbreviations: MIS, minimally invasive surgery repair; n.s., not significant; SD, standard deviation.
*p< 0.05 was considered statistically significant.
1888
|
MIS AND TENDON ELONGATION
outcomes compared to the open surgical repair. Therefore,
minimally invasive surgery may be considered a more
suitable option for acute Achilles tendon repair to achieve
overall better outcomes.
AUTHOR CONTRIBUTIONS
Taner Karlidag: Conceptualization; methodology; proj-
ect administration; investigation; data curation; formal
analysis; validation; visualization; writing—original
draft; writing—review and editing. Olgun Bingol:
Conceptualization; investigation; data curation; formal
analysis; writing—review and editing. Burak Kulakoglu:
Investigation; data curation; formal analysis; writing—
review and editing. Omer Halit Keskin: Investigation;
data curation; formal analysis; writing—review and editing.
Atahan Durgal: Investigation; data curation; formal
analysis; writing—review and editing. Guzelali
Ozdemir: Supervision; investigation; data curation;
formal analysis; writing—review and editing.
CONFLICT OF INTEREST STATEMENT
The authors declare no conflict of interest.
DATA AVAILABILITY STATEMENT
The authors confirm that the data supporting the
findings of this study are available within the article.
ETHICS STATEMENT
The local ethics committee authorised the study
(E1‐22‐2557), which was performed in accordance
with the ethical standards of the Declaration of Helsinki.
Patients gave written informed consent before
participation.
ORCID
Taner Karlidag http://orcid.org/0000-0003-
4250-0444
REFERENCES
1. Barfod KW, Riecke AF, Boesen A, Hansen P, Maier JF,
Døssing S, et al. Validation of a novel ultrasound measurement
of achilles tendon length. Knee Surg Sports Traumatol Arthrosc.
2015;23(11):3398–406. https://doi.org/10.1007/s00167-014-
3175-2
2. Baxter JR, Hullfish TJ, Chao W. Functional deficits may be
explained by plantarflexor remodeling following Achilles tendon
rupture repair: preliminary findings. J Biomech. 2018;79:238–
42. https://doi.org/10.1016/j.jbiomech.2018.08.016
3. Bingol O, Ozdemir G, Karlidag T, Korucu A, Yasar NE,
Deveci A. Impact of posterior malleolus fixation on clinical and
functional results. J Am Podiatr Med Assoc. 2023;113(1):
21–008. https://doi.org/10.7547/21-008
4. Brorsson A, Willy RW, Tranberg R, Grävare Silbernagel K.
Heel‐rise height deficit 1 year after Achilles tendon rupture
relates to changes in ankle biomechanics 6 years after injury.
Am J Sports Med. 2017;45(13):3060–8. https://doi.org/10.1177/
0363546517717698
5. Carmont MR, Grävare Silbernagel K, Brorsson A, Olsson N,
Maffulli N, Karlsson J. The Achilles tendon resting angle as an
indirect measure of Achilles tendon length following rupture,
repair, and rehabilitation. Asia Pac J Sports Med Arthrosc
Rehabil Technol. 2015;2(2):49–55. https://doi.org/10.1016/j.
asmart.2014.12.002
6. Conway KA, Franz JR. Shorter gastrocnemius fascicle lengths
in older adults associate with worse capacity to enhance push‐
offintensity in walking. Gait Posture. 2020;77:89–94. https://doi.
org/10.1016/j.gaitpost.2020.01.018
7. Drazan JF, Hullfish TJ, Baxter JR. Muscle structure governs
joint function: linking natural variation in medial gastrocnemius
structure with isokinetic plantar flexor function. Biol Open.
2019;8(12):bio048520. https://doi.org/10.1242/bio.048520
8. Dyment NA, Liu C‐F, Kazemi N, Aschbacher‐Smith LE,
Kenter K, Breidenbach AP, et al. The paratenon contributes to
scleraxis‐expressing cells during patellar tendon healing. PLoS
One. 2013;8(3):e59944. https://doi.org/10.1371/journal.pone.
0059944
9. Eliasson P, Agergaard A‐S, Couppé C, Svensson R,
Hoeffner R, Warming S, et al. The ruptured Achilles tendon
elongates for 6 months after surgical repair regardless of early
or late weightbearing in combination with ankle mobilization: a
randomized clinical trial. Am J Sports Med. 2018;46(10):2492–
502. https://doi.org/10.1177/0363546518781826
10. von Elm E, Altman DG, Egger M, Pocock SJ, Gøtzsche PC,
Vandenbroucke JP. The Strengthening the Reporting of
Observational Studies in Epidemiology (STROBE) statement:
guidelines for reporting observational studies. Lancet.
2007;370(9596):1453–7. https://doi.org/10.1016/S0140-
6736(07)61602-X
11. Forlenza EM, Lavoie‐Gagne OZ, Lu Y, Diaz CC, Chahla J,
Forsythe B. Return to play and player performance after Achilles
tendon rupture in UEFA professional soccer players: a
matched‐cohort analysis of players from 1999 to 2018. Orthop
J Sports Med. 2021;9(9):232596712110241. https://doi.org/10.
1177/23259671211024199
12. Francis CA, Lenz AL, Lenhart RL, Thelen DG. The modulation of
forward propulsion, vertical support, and center of pressure by the
plantarflexors during human walking. Gait Posture. 2013;38(4):
993–7. https://doi.org/10.1016/j.gaitpost.2013.05.009
13. Grassi A, Rossi G, D'Hooghe P, Aujla R, Mosca M,
Samuelsson K, et al. Eighty‐two per cent of male professional
football (soccer) players return to play at the previous level two
seasons after Achilles tendon rupture treated with surgical
repair. Br J Sports Med. 2020;54(8):480–6. https://doi.org/10.
1136/bjsports-2019-100556
14. Heikkinen J, Lantto I, Flinkkila T, Ohtonen P, Niinimaki J,
Siira P, et al. Soleus atrophy is common after the nonsurgical
treatment of acute Achilles tendon ruptures: a randomized
clinical trial comparing surgical and nonsurgical functional
treatments. Am J Sports Med. 2017;45(6):1395–404. https://
doi.org/10.1177/0363546517694610
15. Heikkinen J, Lantto I, Piilonen J, Flinkkilä T, Ohtonen P,
Siira P, et al. Tendon length, calf muscle atrophy, and
strength deficit after acute achilles tendon rupture. J Bone Jt
Surg. 2017;99(18):1509–15. https://doi.org/10.2106/JBJS.
16.01491
16. Hong CC, Schaarup SO, Calder J. Differential elongation of the
gastrocnemius after Achilles tendon rupture: a novel technique
of selective shortening to treat push‐offweakness with case
series and literature review. Knee Surg Sports Traumatol
Arthrosc. 2023;31:6046–51. https://doi.org/10.1007/s00167-
023-07619-1
17. Hullfish TJ, O'Connor KM, Baxter JR. Medial gastrocnemius muscle
remodeling correlates with reduced plantarflexor kinetics 14 weeks
following Achilles tendon rupture. J Appl Physiol. 2019;127(4):
1005–11. https://doi.org/10.1152/japplphysiol.00255.2019
18. Kastoft R, Barfod K, Bencke J, Speedtsberg MB, Hansen SB,
Penny JØ. 1.7 cm elongated Achilles tendon did not alter
walking gait kinematics 4.5 years after non‐surgical treatment.
MIS AND TENDON ELONGATION
|
1889
Knee Surg Sports Traumatol Arthrosc. 2022;30(10):3579–87.
https://doi.org/10.1007/s00167-022-06874-y
19. Kitaoka HB, Alexander IJ, Adelaar RS, Nunley JA, Myerson MS,
Sanders M. Clinical rating systems for the ankle–hindfoot,
midfoot, hallux, and lesser toes. Foot Ankle Int. 1994;15(7):
349–53. https://doi.org/10.1177/107110079401500701
20. Larsson E, Helander KN, Falkheden Henning L, Heiskanen M,
Carmont MR, Grävare Silbernagel K, et al. Achilles tendon resting
angle is able to detect deficits after an Achilles tendon rupture, but it
is not a surrogate for direct measurements of tendon elongation,
function or symptoms. Knee Surg Sports Traumatol Arthrosc.
2022;30:4250–7. https://doi.org/10.1007/s00167-022-07142-9
21. Lyras DN, Kazakos K, Tryfonidis M, Agrogiannis G, Botaitis S,
Kokka A, et al. Temporal and spatial expression of TGF‐β1inan
Achilles tendon section model after application of platelet‐rich
plasma. Foot Ankle Surg. 2010;16(3):137–41. https://doi.org/
10.1016/j.fas.2009.09.002
22. Maluf KS, Mueller MJ, Strube MJ, Engsberg JR, Johnson JE.
Tendon Achilles lengthening for the treatment of neuropathic
ulcers causes a temporary reduction in forefoot pressure
associated with changes in plantar flexor power rather than
ankle motion during gait. J Biomech. 2004;37(6):897–906.
https://doi.org/10.1016/j.jbiomech.2003.10.009
23. Manegold S, Tsitsilonis S, Gehlen T, Kopf S, Duda GN,
Agres AN. Alterations in structure of the muscle–tendon unit
and gait pattern after percutaneous repair of Achilles tendon
rupture with the Dresden instrument. Foot Ankle Surg.
2019;25(4):529–33. https://doi.org/10.1016/j.fas.2018.04.004
24. Minhas SV, Kester BS, Larkin KE, Hsu WK. The effect of an
orthopaedic surgical procedure in the National Basketball
Association. Am J Sports Med. 2016;44(4):1056–61. https://
doi.org/10.1177/0363546515623028
25. Müller SA, Evans CH, Heisterbach PE, Majewski M. The role of
the paratenon in Achilles tendon healing: a study in rats. Am
J Sports Med. 2018;46(5):1214–9. https://doi.org/10.1177/
0363546518756093
26. Müller SA, Quirk NP, Müller‐Lebschi JA, Heisterbach PE,
Dürselen L, Majewski M, et al. Response of the injured tendon
to growth factors in the presence or absence of the paratenon.
Am J Sports Med. 2019;47(2):462–7. https://doi.org/10.1177/
0363546518814534
27. Nilsson‐Helander K, Thomeé R, Grävare‐Silbernagel K, Thomeé P,
Faxén E, Eriksson BI, et al. The Achilles Tendon Total Rupture
Score (ATRS): development and validation. Am J Sports Med.
2007;35(3):421–6. https://doi.org/10.1177/0363546506294856
28. Okoroha KR, Ussef N, Jildeh TR, Khalil LS, Hasan L, Bench C,
et al. Comparison of tendon lengthening with traditional versus
accelerated rehabilitation after achilles tendon repair: A prospective
randomized controlled trial. Am J Sports Med. 2020;48(7):1720–6.
https://doi.org/10.1177/0363546520909389
29. Olsson N, Nilsson‐Helander K, Karlsson J, Eriksson BI, Thomée R,
Faxén E, et al. Major functional deficits persist 2 years after acute
Achilles tendon rupture. Knee Surg Sports Traumatol Arthrosc.
2011;19(8):1385–93. https://doi.org/10.1007/s00167-011-1511-3
30. Orishimo KF, Burstein G, Mullaney MJ, Kremenic IJ, Nesse M,
McHugh MP, et al. Effect of knee flexion angle on achilles
tendon force and ankle joint plantarflexion moment during
passive dorsiflexion. J Foot Ankle Surg. 2008;47(1):34–9.
https://doi.org/10.1053/j.jfas.2007.10.008
31. Rosso C, Buckland DM, Polzer C, Sadoghi P, Schuh R,
Weisskopf L, et al. Long‐term biomechanical outcomes after
Achilles tendon ruptures. Knee Surg Sports Traumatol Arthrosc.
2015;23(3):890–8. https://doi.org/10.1007/s00167-013-2726-2
32. Schaarup SO, Wetke E, Konradsen LAG, Calder JDF. Loss of
the knee–ankle coupling and unrecognized elongation in
Achilles tendon rupture: effects of differential elongation of the
gastrocnemius tendon. Knee Surg Sports Traumatol Arthrosc.
2021;29(8):2535–44. https://doi.org/10.1007/s00167-021-
06580-1
33. Sheth U, Wasserstein D, Jenkinson R, Moineddin R, Kreder H,
Jaglal SB. The epidemiology and trends in management of
acute Achilles tendon ruptures in Ontario. Bone Joint J.
2017;99‐B1:78–86. https://doi.org/10.1302/0301-620X.99B1.
BJJ-2016-0434.R1
34. Shu L, Hua T, Wang Y, Li Q, Feng DD, Tao X. In‐shoe plantar
pressure measurement and analysis system based on fabric
pressure sensing array. IEEE Trans Inf Technol Biomed.
2010;14(3):767–75. https://doi.org/10.1109/TITB.2009.2038904
35. Silbernagel KG, Shelley K, Powell S, Varrecchia S. Extended
field of view ultrasound imaging to evaluate Achilles tendon
length and thickness: a reliability and validity study. Muscles
Ligaments Tendons J. 2016;6(1):104–10. https://doi.org/10.
11138/mltj/2016.6.1.104
36. Silbernagel KG, Steele R, Manal K. Deficits in heel‐rise height
and Achilles tendon elongation occur in patients recovering
from an achilles tendon rupture. Am J Sports Med. 2012;40(7):
1564–71. https://doi.org/10.1177/0363546512447926
37. Tengman T, Riad J. Three‐dimensional gait analysis following
Achilles tendon rupture with nonsurgical treatment reveals long‐
term deficiencies in muscle strength and function. Orthop
J Sports Med. 2013;1(4):232596711350473. https://doi.org/10.
1177/2325967113504734
38. Xu T, Liu X, Tian J, Liu S, Mi J, Xu Y, et al. Endoscopic‐assisted
locking block modified Krackow technique combined with a V‐Y
flap for chronic Achilles tendon rupture. Knee Surg Sports
Traumatol Arthrosc. 2023;31(1):86–93. https://doi.org/10.1007/
s00167-022-07167-0
39. Zellers JA, Baxter JR, Grävare Silbernagel K. Functional ankle
range of motion but not peak Achilles tendon force diminished
with heel‐rise and jumping tasks after Achilles tendon repair.
Am J Sports Med. 2021;49(9):2439–46. https://doi.org/10.1177/
03635465211019436
How to cite this article: Karlidag T, Bingol O,
Kulakoglu B, Keskin OH, Durgal A, Ozdemir G.
Effects of tendon elongation on plantar pressure and
clinical outcomes: a comparative analysis between
open repair and minimally invasive surgery. Knee
Surg Sports Traumatol Arthrosc. 2024;32:1880–90.
https://doi.org/10.1002/ksa.12163
1890
|
MIS AND TENDON ELONGATION
