Case Report
https://doi.org/10.14517/aosm16010
pISSN 2289-005X·eISSN 2289-0068
Additional post-tie for unstable femoral suspensory fixation
during anterior cruciate ligament reconstruction using
TightRope® RT: clinical reports on 3 cases
Seung Hyuk Choi, Jeong Ku Ha, Dal Jae Jun, Jeong Gook Seo, Jung Ho Park
Department of Orthopedic Surgery, Seoul Paik Hospital, Inje University College of Medicine, Seoul, Korea
Femoral suspension devices in anterior cruciate ligament reconstruction provide a simple and safe way to make a strong
femoral fixation of grafts. But making an accurate femoral fixation of the graft is technically difficult and femoral cortical fractures may induce instability and, thereby, fixation loss. To this end, we investigated the effectiveness of additional
post-ties to augment femoral fixation in adjustable-loop fixation techniques such as the TightRope® RT system (Arthrex
Inc., USA). The additional post-ties were created by re-using the shortening strands, which are used to advance the buttons of the TightRope® RT to the femoral cortex, to tie an auxiliary knot around a screw and washer at the superior femoral tunnel.
Keywords: Anterior cruciate ligament reconstruction; TightRope® RT; Post-tie; Suspensory fixation
INTRODUCTION
Injury of the anterior cruciate ligament (ACL) is one of
the most common soft-tissue injuries of the knee [1]. ACL
injuries are often associated with pain, anterior displacement of the tibia, and loss in rotational stability, resulting
in reduced activity [2]. Thus, ACL reconstruction is essential to restore knee function to pre-injury levels especially
in young and active patients. A myriad of techniques and
methods exists for graft fixation in ACL reconstruction,
which all aims to make a strong fixation of the graft [3].
Although it remains controversial as to which fixation
method is the most ideal and provides the most favorable
clinical outcomes, the suspensory technique, i.e., the Endobutton system (Smith & Nephew Endoscopy, Andover,
MA, USA), introduced in the early 1990s, has generally
been accepted as the method that provides strong graft
fixation in a safe and simple way. Recently, suspensory
devices such as EndoButton, ToggleLoc with ZipLoop,
and TightRope® RT (Arthrex Inc., Naples, FL, USA) are
Arthroscopy and
Orthopedic Sports Medicine
AOSM
34
widely used by authors’ preference [4,5]. However, there
is possibility of major complications suspensory fixation
technique such as stuck-in or escaping of button via tunnel, necrosis of the femoral cortex, and interposition of
soft tissue between button and cortex [6–8]. Therefore,
to provide a solution to the limitations of suspensory
fixation techniques, we investigated the effectiveness of
using an augmentation post-tie in femoral suspensory
fixation such as the TightRope® RT system during ACL
reconstruction. In this study, we report the outcomes of
using post-tie in patients with femoral cortex fracture or
unstable cortical fixation at the entrance of femoral tunnel may lead to femoral fixation loss.
CASE REPORTS
Case 1
A 33-year-old male basketball player was hospitalized
because of pain in his left knee. The injury, which was
sustained as he made an abrupt turn while playing, was
Received June 24, 2016; Revised August 22, 2016; Accepted August 23, 2016
Correspondence to: Jeong Ku Ha, Department of Orthopedic Surgery, Seoul Paik Hospital, Inje University College of Medicine, 9
Mareunnae-ro, Jung-gu, Seoul 04551, Korea. Tel: +82-2-2270-0028, Fax: +82-2-2270-0023, E-mail: [email protected]
Copyright © 2017 Korean Arthroscopy Society and Korean Orthopedic Society for Sports Medicine. All rights reserved.
This is an open-access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/
by-nc/4.0) which permits unrestricted noncommercial use, distribution, and reproduction in any medium, provided the original work is properly cited.
CC
Arthrosc Orthop Sports Med 2017;4(1):34-38
Seung Hyuk Choi, et al. Post-tie for unstable femoral suspensory fixation during ACL reconstruction
diagnosed ACL insufficiency. We performed arthroscopic
ACL reconstruction to treat it. We used the outside-in
method and the FlipCutter® system (Arthrex Inc.) to make
anatomical femoral tunnel. First, we harvested a hamstring autograft, which was prepared into four strands,
and connected it to the TightRope® RT. After passing it
through the femoral tunnel, we fixed the autograft. Although we confirmed using arthroscopy that the button
of the TightRope® RT was well impacted onto the femoral
cortex, the button seemed to be fixed rather unstably at
the cortical indentation of the entrance of the femoral
tunnel (Fig. 1). Next, we made a 3-cm extension of the
skin incision at the lateral distal femur proximally to expose the femoral cortex. We connected a 4.5-mm cortical
screw to a 6.5-mm washer and inserted the screw-washer
component perpendicular to the distal femoral shaft.
Afterwards, we tied the shortening strands of the TightRope® RT securely around the screw. Once we tensioned
the graft and confirmed it arthroscopically, we made a
tibial fixation by using a bioabsorbable interference screw
and a cortical screw-washer component.
The patient was administered an orthosis immediately
postoperatively until the 6th postoperative week and
were allowed full weight-bearing under full extension or
within the capacity of the patient. Range of motion exercises were begun after the 1st postoperative week. At the
3-month follow-up, we did not observe radiologically
any slippage of the button within the femoral tunnel
(Fig. 2). We found that our parameters of physical outcomes improved with respect to their preoperative scores:
the Lachman score improved from a preoperative Stage 2
to a postoperative Stage 1; the pivot shift improved from
Stage 2 to Stage 1; the Tegner score improved from 2 to 5;
the Lysholm score improved from 76 to 89; and lastly the
International Knee Documentation Committee (IKDC)
score improved from 43 to 65.
Case 2
A 36-year-old male patient was admitted to our hospital
because of pain in the right knee after an abnormal twisting of the knee whilst playing baseball. We performed
arthroscopic ACL reconstruction to treat his injury. First,
we used the outside-in method and the FlipCutter® system (Arthrex Inc.) to make an anatomical femoral tunnel. We harvested a hamstring autograft, prepared it into
four strands, and connected it to the TightRope® RT. We
passed the four-stranded autograft through the femoral
tunnel and fixed it onto the femoral cortex by using the
TightRope® RT button. We confirmed that the button
was well-impacted by pulling the TightRope® RT from
the distal end rather than by arthroscopy. Afterwards, we
carried out 15 rounds of cyclic loading. Arthroscopically,
we found that the graft had moved downwards 5 mm
distally compared to its initial position, and using a Carm, we found that the button was seated on the inner
femoral bone. Since the initial femoral tunnel was 25 mm
in length, we were able to deduce that approximately 20
A
Fig. 1. On arthroscopy, the button of the TightRope® RT (Arthrex Inc.)
was found to be hanging insecurely and seated in a cortical indentation
of the cortical surface near the femoral tunnel entrance.
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B
Fig. 2. (A) After exposure of the femoral cortex, a cortical screw combined with a washer was inserted perpendicular to the distal femoral
shaft and a post tie was knotted around it. (B) At the 3-month followup radiography, we did not observe button slippage within the femoral
tunnel.
35
Seung Hyuk Choi, et al. Post-tie for unstable femoral suspensory fixation during ACL reconstruction
mm of graft was inside the femoral tunnel; we agreed
that there was sufficient graft inside the femoral tunnel to
perform fixation in its existing position. We made a 3-mm
extension of the skin incision of the lateral distal femur
to expose the femoral cortex; then, we connected the 4.5mm cortical screw to the 6.5-mm washer and placed the
screw-washer component perpendicular to the distal
femoral shaft. Then the shortening strands of the TightRope® RT were tied tightly around the screw. Confirming
the tension of the graft by arthroscope, we fixed the tibial
end of the tunnel with a bioabsorbable interference screw
and then with a staple additionally.
The same rehabilitation protocol was followed in Case
2 as in Case 1. At the 3-month follow-up, we found radiologically that the button remained intact without any sign
of slipping (Fig. 3). Physical examination of the patient
showed that the Lachman grade improved from a preoperative Grade 3 to a postoperative Grade 1; the pivot
shift score improved from Grade 2 to Grade 1; the Tegner
score, from 3 to 5; the Lysholm score, from 78 to 87; and
the IKDC score, from 52 to 63.
Case 3
A 49-year-old male patient was hospitalized after sustaining an injury of combined medial ligament/ACL tears
and posterolateral instability from a car accident. Although he had received ACL reconstruction and posterolateral complex reconstruction for his injury, re-injury
led to recurrent symptoms of ACL instability and valgus
instability on the 4th postoperative year. To address the
recurrent instability, we performed medial collateral ligament reconstruction and revision of the arthroscopic
ACL reconstruction. For the ACL reconstruction, we used
the Achilles allograft and the pre-existing femoral tunnel
that had been made at the initial reconstruction. However, arthroscopically, we observed that the cortical bone
integrity at the entrance of the femoral tunnel, which
would support the button of the TightRope® RT, was
poor, likely on account of previous interventions (viz., the
ACL reconstruction and the posterolateral structure reconstruction). First, we passed the graft hooked onto the
TightRope® RT through the femoral tunnel and fixed it
onto the femoral cortical bone. Then we tied the shortening strands, which are connected to the button, around
the cortical screw that is running perpendicular to the
distal femoral shaft, making an augmentation post-tie
fixation. We exerted cyclic loads to confirm that the femoral fixation of the graft was sturdy. Lastly, we made a tibial
fixation by using a bioabsorbable interference screw, a
cortical screw, and a washer.
The patient was administered an immobilizing long leg
cast for 2 weeks postoperatively to restrict joint movement. Range of motion exercises were begun thereafter,
and joint motions to 90° were permitted from the 6th
postoperative week. Partial weight-bearing on the leg cast
was performed for 6 weeks. At the 3-month follow-up, we
could not find radiological signs of button sliding within
the femoral tunnel.
DISCUSSION
A
B
Fig. 3. Compared to the preoperative radiograph (A), the radiograph
taken at the 3-month follow-up show no slippage of button within the
femoral tunnel (B).
36
In general, graft healing has been shown to takes around
6 to 12 weeks [9]. A strong integration of the graft is vital
for early joint exercises and weight-bearing to be successful, especially during ACL reconstruction using soft tissue
grafts such as hamstring tendons [10]. The mechanisms
of femoral fixation have been classified into 3 types: compression fixation, suspension fixation, and expansion
fixation. The femoral fixation of small grafts has been
generally performed using the suspension technique,
most notably the Endobutton® system. However, there
are limitations to using suspensory devices: 1) the placement of grafts on the femoral cortical surface is not accurate; 2) because the ends of the graft end up away from
each other, the resulting bungee cord effect upon movement may cause tunnel expansion; and 3) insufficient
bone stock of the femoral cortical bone or cortical frac-
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Seung Hyuk Choi, et al. Post-tie for unstable femoral suspensory fixation during ACL reconstruction
Fig. 4. A schematic diagram illustrating how the post-tie was made using the shortening strands and the screw and washer inserted at the
superior femoral tunnel.
ture can lead to fixation loss in spite of a strong fixation
[11].
There are no simple reparative measures to address
failed femoral fixation of the graft, especially at the lateral
femoral cortex, during ACL reconstruction using suspensory fixation. Usually, in case of fixation loss, the graft is
taken out extra-articularly and the femoral fixation is reattempted. Or if fixation loss results from, for instance, a
fractured lateral femoral cortex, a large excision is made
at the femur and the graft is fixed using interference
screws. However, this method leads to unnecessarily
prolonged surgery time and an excessively large excision
and might not even be achievable with short grafts. Previously, although a double fixation, such as an inference
screw/corticocancellous cross-pin fixation, has been
used in patients with unsuccessful suspensory fixation,
such methods have been reported to increase the risk
of the graft failure [12]. Thus, there is still a large gap in
the literature concerning alternative methods for failed
femoral fixation of soft tissue grafts.
To this end, we investigated whether the shortening
strands of adjustable-loop fixation techniques, such as
the TightRope® RT system, which are usually used to advance the buttons into the femoral cortex, can be used to
make an augmentation post-tie. In this study, we made
a supplementary post-tie fixation by tying the shortening strands around a screw-washer component at the
superior femoral tunnel to achieve a stable fixation of
grafts (Fig. 4). At the final follow-up, we did not observe
any sliding of the button on radiographs but found that
our parameters of knee stability (Lachman test/pivot
shift test) and physical outcome (Lysholm/Tegner/IKDC
scores) improved with respect to their preoperative values. Altogether, these favorable outcomes denote a wellfunctioning graft. This study indicates that, in outside-in
ACL reconstruction, augmentation post-tie fixation is an
effective adjunct knot for a strong femoral fixation when
suspensory devices alone is insufficient (for instance,
when button slipping or fractures of the femoral cortex
occur). Further, as in Case 3 of our study, the augmentation post-tie can be carried out even when there are concomitant femoral cortical fractures or multiple tunnels
from a previous reconstruction surgery.
CONFLICT OF INTEREST
No potential conflict of interest relevant to this article was
reported.
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