Comparative Study in Primary Repair of Flexor Tendon Injuries Between Two Strands Tendon Repair and Four Strands Tendon Repair

INTRODUCTION
Plastic and hand surgeons use different suture
techniques to repair flexor tendon injuries and
lacerations. Even when competent surgeons fix
and reconstruct such injuries, post-operative complications,
such as tendon ruptures, adhesions and
gap formation still occur [1].
Galen first repaired injured flexor tendon in
the second century [2]. In the Tenth Century, the
Islamic scientist Avicenna described tendon repair
in his book “Al-Qanun-fi-al-Tibb” [3]. In the twentieth
century, Bunnell declared the concept of "no
217
man's land” as a result of poor outcomes following
primary tendon repair [4]. Delayed tendon reconstruction
and tendon grafts became popular by
many surgeons [5,6].
In the fifties of the twentieth century, hand
surgeons recognized the poor outcome following
delayed tendon grafting especially in zone 2 tendon
injuries and primary tendon repair regained its
acceptance from many hand surgeons. Now, primary
tendon repair is the treatment of choice for
flexor tendon injuries. However, different suture
techniques and variable postoperative rehabilitation
protocols still rise the controversies about the
universally accepted management of such injuries
[7].
In this study, we compared the results of repair
of the injured flexor tendons using two different
techniques; the two strands tendon repair and the
four strands tendon repair.
PATIENTS AND METHODS
We conducted this study at Plastic Surgery
Department, Mansoura University, Egypt from
1/11/2017 to 31/10/2018 where thirty two patients
were included and divided into two groups:
• Group A (16 patients): We performed tendon
repair using two strands modified Kessler repair
technique.
• Group B (16 patients): We performed tendon
repair using four strands modified cruciate repair
technique.
Inclusion criteria:
- Hand trauma complicated by flexor tendon injury.
- Age (15-60) years.
Exclusion criteria:
- Polytraumatized patients.
- Previous hand surgery or associated phalangeal
fractures.
- Surgical unfit (comorbid conditions like DM,
heart diseases…..).
We obtained local institutional review board
approval. We obtained an informed consent from
each patient participated in this study. Patients
with flexor tendon injuries were managed in the
same way as trauma cases. Each patient was subjected
to the following:
- Primary survey: Life-threatening injuries are
identified and we started resuscitation of injured
patients.
- Secondary survey: After assurance of stabilized
general conditions of each patient, history taking,
detailed hand examination, laboratory investigations
and imaging were conducted.
Surgical technique:
General anesthesia or supraclavicular nerve
block were used. Applying of tourniquet to decrease
blood loss from the skin incision. Using Zigzag
incision to expose the injured tendon.
Group A: We used two strands (modified Kessler)
technique by using non-absorbable monofilament
(4/0 or 3/0) prolene sutures Fig. (1) followed
by Strengthening of the repair by peripheral epitendinous
suture (6-0 prolene).
Group B: We used four strands (modified cruciate
core suture) using non-absorbable monofilament
(4/0 or 3/0) prolene sutures Fig. (2) with
Strengthening of the repair by doing peripheral
epitendinous suture (6-0 prolene).
In both groups, we put the affected hand and
forearm in dorsal splint extending from beyond
the fingertips to below the elbow with light volar
dressing with 80-90º MCP joints in flexion and
20º wrist in flexion and proximal and distal interphalangeal
joints (PIP/DIP) is fully extended.
Post-operative care:
1- The patient was discharged to the ward. Systemic
antibiotics and proper analgesia were given to
the patient.
2- At the first post-operative day: Removal of the
drains, change of the dressings and patient'
discharge from the hospital were done.
3- The physiotherapy protocol (early active mobilization
protocol).
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In cases with zone 3 injuries, early exercises
were initiated 24 hours after repair while for cases
with zone 2 injuries, exercises were initiated 48
hours after repair. During first 4 weeks, patients
were instructed to do 2 repetitions 4 hourly apart
of passive finger flexion Fig. (3) and active hold
exercises. Full active PIP extension was started
from 1st week. At 4 weeks, splint was discontinued.
3 weeks later, protected passive interphalangeal
extension exercises were started. Full function was
started by 12 weeks.
Outcome measure:
At the 6th post-operative month all patients
were assessed for the outcome of the surgery by:
• Measuring of the active ranges of movement of
all joints (MCP, PIP & DIP) of repaired injured
fingers using a goniometer.
• Calculating of Total Active Motion (TAM) of
affected fingers (by adding of the active flexion
range of motion of metacarpophalangeal joint,
proximal interphalangeal joint and distal interphalangeal
joint minus extension lag of each
joint).
• The Arabic version of the questionnaire of Disabilities
of the arm, shoulder and hand score
(DASH score) was given to all. Thirty questions
were asked to each patient. Score ranged from
30-150. The following formula [(score-30)/1.2]
was used to give the final score from 0 to 100.
Data analysis:
We used the Statistical Package for the Social
Sciences (SPSS) version 20 (SPSS Inc., Chicago,
IL, USA) for the analysis of our results. We compared
the mean values between the two groups
regarding DIP, PIP, MCP joints active flexion,
TAM and DASH score using parametric independent
samples Student's t-test. We considered that
the probability value (p-value) was significant
when it was less than 0.05.
RESULTS
In this study, we operated upon 41 tendons in
32 patients. The causes of cut tendons were injuries
due to sharp instruments (22 patients), crush injuries
(8 cases) and glass injuries (2 cases). Dominant
hands were injured in 15 patients and in nondominant
hands were injured in 17 patients. Patients'
demographic data were shown in (Table 1).
Early post-operative complication included
rupture of one tendon in only one case in group A.
Then re-exploration and re-suturing was done after
Egypt, J. Plast. Reconstr. Surg., January 2020 219
3 weeks from the first surgery. The complications
rate was 6.3% in group A. the overall success rate
of all cases was 96.9%.
Regarding late post-operative follow-up and
outcome assessment:
There was no statistically significant differences
between the two groups. Table (2) shows the postoperative
range of motion of DIP, PIP joints flexion
range of motion and Total Active Movement (TAM)
of the injured fingers.
The DASH score for patients in group A ranges
between 10-30. In group B, it ranges between 2-
26. There was no statistically significant differences
between the results of these two groups.
Table (1): Patients' demographic data.
Characteristic
Age (mean ± SD)
Sex (male/female)
Right/left hand
Zone of injury (two/three)
Affected fingers:
Index
Middle
Little
Thumb
Ring
Group A
29.6±12.11
15/1
9/7
15/1
54334
Group B
30.25±12.17
14/2
5/11
14/2
45337
Table (2): Post-operative outcome measures of patients in
both groups.
PIP flexion ROM:
Mean ± SD
Range
DIP flexion ROM:
Mean ± SD
Range
TAM of fingers ex. thumb:
Mean ± SD
Range
Group A
96.88±3.59
90-100
71.58±2.91
65-75
259±4.9
250-265
Group B
98.68±2.26
95-100
72.73±2.98
70-80
261.8±3.8
255-270
p-value
0.079
0.221
0.068
Fig. (1): Two strand tendon repair (modified Kessler) in little
finger.
Fig. (2): Modified cruciate four strands sutures (intraoperative
photo).
Fig. (3): Post -operative physiotherapy (passive flexion exercises).
DISCUSSION
Since the sixties of the twentieth century, the
concept of primary flexor tendon repair started to
gain popularity among surgeons [8]. Advances in
understanding of flexor tendon anatomy, response
to injury, healing mechanisms together with improvements
in suture materials, suture repair designs,
use of magnification and advanced rehabilitation
protocols resulted in improved outcome of
primary flexor tendon repair over delayed tendon
grafting [9].
However, the goals of surgery for treatment of
flexor tendon injuries are still constant. They
include achieving precise coaptation of the ends
of the lacerated tendon in order to permit successful
rehabilitation protocol that improve tendon gliding
and prevent adhesions formations and eventually
results in restoration of normal ranges of motion
of the affected finger [10].
Tendon suture techniques were assessed with
concern to their materials, reapir technique and
usage of the epitendinous sutures. The optimal
suture must be reliable, easy to achieve, result in
identical coadaptation of the severed edges of
injured tendon, produce a minor gap, provide
minimal interference with vascularity of tendon
and provide adequate power to permit quick rehabilitation
[11].
The more the number of threads that transverse
the tendon repair area, the stronger the power of
the repair. Two, four, six [12] or even eight [13]
strands tendon repair suture techniques have been
described. Obviously, it could be shown that the
biomechanical stability increases with number of
core suture. However, surgeons aim to make tendon
sutures easier and to preserve the suture power
without increasing the technical difficulties [14].
The double-strand technique had considerably
greater formation of gap than found in the fourstrand
technique [15]. However, the in vitro benefits
of multi-strands tendon repair techniques are not
necessarily reflected on results in vivo [16]. In
addition, the usage of epitendinous suture is important
to augments the confrontation of the repaired
tendon by 10% to 50% and decreases the
incidence of gap formation [17].
Kleinert passive motion rehabilitation protocol
is a widely used protocol [18]. Frueh et al., in terms
of Total Active Motion (TAM), did not observe
any difference between early mobilization and
controlled active motion [19]. In addition, very
early active post-operative exercises can achieve
minimal complication rate [20].
Interestingly, in an meta-analysis, there were
no any statistically significant differences between
double and multiple strands suture repair [21]. This
why there is no universally accepted protocol for
management of flexor tendon injuries.
The debate extends to the assessment tool for
the outcome of surgery. Only a single joint ROM
assessment in one finger using goniometer was
shown to be reliable. Measuring of the sum of the
ROM of two or three joints is less reliable [22].
220 Vol. 44, No. 1 / Comparative Study in Primary Repair of Flexor Tendon Injuries
However it is only a rough measure to assess the
outcome of surgery. Assessment using (TAM/ROM)
is difficult (needs multiple measuring) and debatable
(depends on hand dominance and affected
finger) [23]. Questionnaire DASH score needs
cooperative and well informed patient and the
questionnaire is not specific to flexor tendon injuries.
It is an oral questioionnaire that depends on
the patients answers that may be incorrect or misleading
[24]. Regarding hand grip strength, several
studies did not prefer hand grip and pinch as a tool
for assessment of outcome for tendon repair surgery
(depends on intrinsic muscles plus flexor tendon,
differs from dominant and nondominant hands and
affected by age and sex) [25].
Conclusion:
In this study, we noticed that Cruciate (fourstrand)
suture procedures are easy to accomplish,
offer less interfering with tendon gliding and are
adequately strong for an early post-operative rehabilitation
program. Regarding total active range
of motion and DASH score, there were no statistically
significant differences between the four
strands or two strands groups.