Seung Hyuk Choi, Jeong Ku Ha, Dal Jae Jun, Jeong Gook Seo, Jung Ho Park

Transcription

1 Case Report pissn X eissn 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 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 Arthroscopy and Orthopedic Sports Medicine AOSM 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: , Fax: , revo94@daum.net Copyright 2017 Korean Arthroscopy Society and Korean Orthopedic Society for Sports Medicine. All rights reserved. CC This is an open-access article distributed under the terms of the Creative Commons Attribution Non-Commercial License ( by-nc/4.0) which permits unrestricted noncommercial use, distribution, and reproduction in any medium, provided the original work is properly cited. 34 Arthrosc Orthop Sports Med 2017;4(1):34-38

2 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 Tight- Rope 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 C- arm, 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 B 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. 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

3 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 4.5- mm 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 Tight- Rope 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 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). B 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- 36

4 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. REFERENCES 1. Benjaminse A, Gokeler A, van der Schans CP. Clinical diagnosis of an anterior cruciate ligament rupture: a meta-analysis. J Orthop Sports Phys Ther 2006;36: Tashman S, Collon D, Anderson K, Kolowich P, Anderst W. Abnormal rotational knee motion during running after anterior cruciate ligament reconstruction. Am J Sports Med 2004;32: Kurosaka M, Yoshiya S, Andrish JT. A biomechanical comparison of different surgical techniques of graft fixation in anterior cruciate ligament reconstruction. Am J Sports Med 1987;15: Kamelger FS, Onder U, Schmoelz W, Tecklenburg K, Arora R, Fink C. Suspensory fixation of grafts in anterior cruciate ligament reconstruction: a biomechanical comparison of 3 implants. Arthroscopy 2009;25: Petre BM, Smith SD, Jansson KS, et al. Femoral cortical suspension devices for soft tissue anterior cruciate ligament reconstruction: a comparative biomechanical study. Am J Sports Med 2013;41: Karaoglu S, Halici M, Baktir A. An unidentified pitfall of Endobutton use: case report. Knee Surg Sports Traumatol Arthrosc 2002;10: Miller MD. EndoButton drill bit failure. Arthroscopy 2002;18: Simonian PT, Behr CT, Stechschulte DJ Jr, Wickiewicz TL, Warren 37

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