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Outcome of Arthroscopic Single-Bundle Versus Double-Bundle Reconstruction of the Anterior Cruciate Ligament: A Preliminary 2-Year Prospective Study
Outcome of Arthroscopic Single-Bundle Versus Double-Bundle Reconstruction of the Anterior Cruciate Ligament: A Preliminary 2-Year Prospective Study Se-Jin Park, M.D., Young-Bok Jung, M.D., Hwa-Jae Jung, M.D., Ho-Joong Jung, M.D., Hun Kyu Shin, M.D., Eugene Kim, M.D., Kwang-Sup Song, M.D., Gwang-Sin Kim, M.D., Hye-Young Cheon, P.A., and Seonwoo Kim, Ph.D.
Purpose: The purpose of this study was to compare the clinical results of arthroscopic single-bundle and double-bundle anterior cruciate ligament (ACL) reconstruction. Methods: We designed a prospective study that included patients with an isolated ACL injury. From April 2004 to February 2007, of 147 patients who underwent ACL reconstruction, 113 were included in this study. We serially obtained clinical and radiologic data preoperatively and postoperatively. We compared preoperative data and data at 2 years postoperatively in patients who had undergone single-bundle ACL reconstruction versus patients who had undergone double-bundle ACL reconstruction. There were 50 single-bundle reconstructions and 63 double-bundle reconstructions. Anteroposterior stability was assessed objectively by anterior stress radiographs with the telos device (telos, Marburg, Germany) and the maximal manual test with the KT-2000 arthrometer (MEDmetric, San Diego, CA). Rotational stability was determined by lateral pivot-shift test. The clinical results were assessed by International Knee Documentation Committee and Orthopadische Arbeitsgruppe Knie scores and Tegner activity scale. In addition, we evaluated postoperative thigh circumference and range of motion. Results: Residual anteroposterior laxity determined at 2 years postoperatively by telos and KT-2000 was 1.74mm ⫾ 1.67mm and 1.79mm ⫾ 1.56mm, respectively, in the single-bundle reconstruction group and 1.63mm ⫾ 1.50mm and 1.61mm ⫾ 1.22mm, respectively, in the doublebundle reconstruction group. There were no statistically significant differences. For the lateral pivot-shift test done at 2 years postoperatively, there was no statistically significant difference. In addition, clinical results such as International Knee Documentation Committee score, Orthopadische Arbeitsgruppe Knie score, Tegner activity scale, thigh circumference, and range of motion showed no significant differences between the 2 groups. Conclusions: Double-bundle reconstruction of the ACL by a method using 2 femoral tunnel and 2 tibial tunnels showed no differences in stability results or any other clinical aspects or in terms of patient satisfaction. Level of Evidence: Level II, prospective comparative study.
From the Department of Orthopedic Surgery, School of Medicine, Kangbuk Samsung Hospital, Sungkyunkwan University (S-J.P., H-J.J., H.K.S., E.K., G-S.K.); Knee Center, Department of Orthopedic Surgery, Chung-Ang University Hospital (Y-B.J., H-J.J., K-S.S., H-Y.C.); and Biostatistics Team, Samsung Biomechanical Research Institute (S.K.), Seoul, South Korea. The authors report no conflict of interest. Received December 29, 2008; accepted September 9, 2009. Address correspondence and reprint requests to Young-Bok Jung, M.D., Knee Center, Department of Orthopaedic Surgery, Chung-Ang University Hospital, 224-1, Heukseok-dong, Dongjak-gu, 156-755, Seoul, South Korea. E-mail: [email protected] © 2010 by the Arthroscopy Association of North America 0749-8063/10/2605-8724$36.00/0 doi:10.1016/j.arthro.2009.09.006
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Arthroscopy: The Journal of Arthroscopic and Related Surgery, Vol 26, No 5 (May), 2010: pp 630-636
SINGLE- AND DOUBLE-BUNDLE ACL RECONSTRUCTION
R
econstruction of the anterior cruciate ligament (ACL) is the most frequently performed reconstructive surgery in the knee. To date, the most widely attempted technique, and thus the gold standard for ACL reconstruction, has been arthroscopic singlebundle reconstruction.1-4 Single-bundle ACL reconstructions have provided excellent success rates of over 80%, but some authors have noted residual instability and patient dissatisfaction after surgery.5-7 Several anatomic studies have shown that the ACL consists of 2 major functional bundles: anteromedial (AM) and posterolateral (PL).8,9 Each bundle has distinct and complementary roles. In knee extension the PL bundle is tight and the AM bundle is loose. As the knee flexes, the AM bundle becomes tight and the PL bundle becomes lax. In addition, the PL bundle is more responsible for rotational stability.10 Several biomechanical studies suggest that double-bundle ACL reconstruction has advantages in terms of both anterior knee stability and rotational stability in the ACL-deficient knee compared with single-bundle ACL reconstruction.11-14 So, currently, there is more focus on double-bundle ACL reconstruction than single-bundle reconstruction. Even though such anatomic studies and biomechanical studies support the basis of double-bundle ACL reconstruction, there are still disputes about the results of single-bundle versus double-bundle reconstruction of the ACL. Furthermore, several meta-analysis studies have shown that double-bundle ACL reconstruction does not result in significant differences compared with single-bundle reconstruction.15-17 The purpose of this study was to evaluate the clinical outcome of arthroscopic double-bundle ACL reconstruction compared with that of single-bundle ACL reconstruction in a prospective, randomized clinical study. We hypothesized that double-bundle ACL reconstruction with hamstring tendon autograft using 2 tibial tunnels and 2 femoral tunnels would be advantageous in restoring anterior and rotational stability, as well as providing better objective clinical results, compared with single-bundle reconstruction. METHODS From April 2004 to February 2007, 147 consecutive ACL reconstruction surgeries were performed by the senior surgeon according to a prospective study design. Inclusion criteria were primary ACL reconstruction with no combined posterior cruciate ligament injury, lateral collateral ligament injury, PL rotatory instability, or fracture around knee; no previous knee
631
ligament surgery; no arthritic changes; no subtotal or total meniscectomy; no malalignment; and a normal contralateral knee. In cases of combined acute medial collateral injuries, ACL reconstruction was done after appropriate conservative treatment for 2 weeks with a long leg splint and then another 4 weeks with a brace and confirmation of good stability of the medial collateral ligament by physical examination. None of the participants had undergone reconstruction of the medial collateral ligament. Patients were excluded from the study when the examination under anesthesia or intraoperative findings did not meet the previously mentioned inclusion criteria. Patients were sequentially selected to undergo either single-bundle or double-bundle reconstruction based on order of admittance to our hospital. Of the 147 cases, 121 were found to have met our inclusion criteria. However, 7 cases did not undergo follow-up within 2 years after surgery, and 1 case was omitted because revision ACL surgery was performed after postoperative infection developed. Of the 113 patients, 50 comprised the single-bundle reconstruction group (group S) and 63 comprised the double-bundle reconstruction group (group D). Group S patients (34 males and 16 females) were aged between 16 and 54 years, with a mean of 28.3 years, and group D patients (48 males and 15 females) were aged between 17 and 57 years, with a mean of 29.6 years. Regarding corresponding injuries to the ACL, there were 12 patients with medial meniscus tear, 10 with lateral meniscus tear, 5 with medial collateral ligament injury, and 4 with osteochondral defect in group S. In group D there were 15 patients with medial meniscus tear, 13 with lateral meniscus tear, 9 with medial collateral ligament injury, and 8 with osteochondral defect. The patient’s condition was investigated during physician’s office visits preoperatively and at 3, 6, 12, and 24 months postoperatively, and we used preoperative data and data at 2 years postoperatively to analyze and compare surgical results. Objective assessment of anteroposterior (AP) stability was performed by use of radiographs with the telos device (telos, Marburg, Germany) and KT-2000 arthrometer (MEDmetric, San Diego, CA), and rotational instability was assessed by lateral pivot-shift test and clinical results by International Knee Documentation Committee (IKDC) score, Orthopadische Arbeitsgruppe Knie score, and Tegner activity scale. The postoperative physical examination was performed by a specially trained physician assistant in our orthopaedic department. Stress radiographs obtained with the telos device were taken with knee flexion at 90°. We also measured active range of
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motion with a goniometer. In addition, postoperative thigh circumference was measured at 10 cm above the upper pole of the patella with full extension of the knee. The hamstring tendon was harvested from the patient’s normal-functioning limb on the opposite side of injury because of the possibility of tendon extraction affecting rotational instability. Wilcoxon rank sum test and Mann-Whitney U test were used for statistical analysis, and P ⬍ .05 was determined to be statistically significant. The telos stress test and KT-2000 arthrometer test, which were evaluated at 2 years postoperatively, were defined as primary parameters. To detect the minimal clinically meaningful difference of 1.0 in the primary parameters between the 2 groups, this study has a power of 86% given the study sample size and the SDs of the data under a significance level of .05. So, the reason for no significance was not that the study was underpowered; rather, the reason was the small difference between the 2 groups. Surgical Technique of Single-Bundle ACL Reconstruction In a single-bundle reconstruction of the ACL, traditional AM bundle reconstruction with arthroscopy was done with both semitendinosus tendon and gracilis tendon, with each segment folded in half to form a quadruple-thickness replacement graft. First, the tibial tunnel was drilled at a 50° angle in the horizontal plane and approximately 2 cm medial from tibial tuberosity in the sagittal plane. The femoral tunnel was made in the femoral notch positioned at 10 o’clock (right knee) or 2 o’clock (left knee) through a transtibial technique. After insertion of an offset guide through the tibial tunnel at knee flexion of 70° to 80°, a guide pin was inserted into the lateral femoral condyle to a depth of approximately 30 mm. Then, with the knee flexed 90°, a guide pin was inserted completely. Notchplasty was not used. We used the RigidFix system (DePuy Mitek, Raynham, MA) for femoral fixation and bioabsorbable interference screws with an Intrafix technique (DePuy Mitek) for tibial fixation. Surgical Technique of Double-Bundle ACL Reconstruction After extracting the hamstring tendon autografts on the AM side of the uninjured proximal tibia, we assembled the extracted autografts from the semitendinosus tendon into a 3-stranded graft used for AM bundle reconstruction and from the gracilis tendon
FIGURE 1.
Hamstring tendon autograft.
into a 3-stranded graft used for PL bundle reconstruction (Fig 1). We used the 2–femoral tunnel and 2–tibial tunnel technique to reconstruct the double-bundle ACL. After confirmation of the ACL attachment site, a tibial tunnel for the PL bundle, a tibial tunnel for the AM bundle, a femoral tunnel for the PL bundle, and a femoral tunnel for the AM bundle were made one by one. Tunnel placement for ACL reconstruction of both bundles was done according to Yasuda et al.18 The femoral tunnel for the AM bundle was located at the 10:30 (right knee) or 1:30 (left knee) position with respect to the intercondylar area. We used caution to avoid impingement of the roof and posterior cruciate ligament with the reconstructed ACL by trying to direct the tibial tunnel into the axis of the normal ACL, ensuring that the graft was not positioned vertically. In addition, we attempted to prevent friction in the anterior intercondylar area of the inner joint when the knee joint was fully extended by inserting the AM guide pin 2 to 3 mm posterior to the anterior margin of the intercondylar notch. To fix the grafts in the femoral tunnel, the RigidFix system was used for the AM bundle and an EndoButton (Smith & Nephew Endoscopy, Andover, MA) was used for the PL bundle. Because a cortical suspensory fixation with the EndoButton can cause some complications such as bone tunnel widening, and both tunnels for the AM and PL bundles might be put together, we prefer the RigidFix system to the EndoButton for AM bundle fixation.19 The 3-stranded autografts from the semitendinosus tendon were long and thick enough for use with the RigidFix system. During this process, the direction of the RigidFix system must be checked so that it does not transit through the PL bundle.
SINGLE- AND DOUBLE-BUNDLE ACL RECONSTRUCTION No. 5 Ethibond (Ethicon, Somerville, NJ) used at the end of each tendon for suturing of each graft was connected to the measuring device to determine the tension level; the measuring device was pulled with a 10- to 15-lb force as the knee joint underwent cyclic loading at 0° to 90° for 20 cycles. Then, a bioabsorbable screw was inserted through the AM tibial tunnel with a 15-lb tension at 30° of flexion of the knee joint. The PL bundle was also fixed with a bioabsorbable screw under a 10-lb tension at a 5° to 10° flexion angle. During this process, if the length of the graft was too short to use the bioabsorbable screw, a screw with a thickness of 6.5 mm and a washer were used to perform the post tie. During fixation of the PL bundle, there was excursion of the PL bundle graft measuring a few millimeters in most of the patients. After confirmation of full extension of the knee joint and no friction in the anterior intercondylar area, the tension of each graft tendon was assessed with an arthroscopic probe. Rehabilitation With respect to postoperative rehabilitation, the protocol was identical for both groups. For the first 6 weeks, walking with crutches with partial weight bearing was allowed without any brace or splint. Patients were encouraged to restore full extension of the knee joint and strengthen the quadriceps muscle power. Six weeks after surgery, patients returned to performing activities of daily living. Noncontact sports were permitted after 3 months, and contact sports were permitted 1 year after surgery. RESULTS In group S preoperative AP instability as determined with the telos device and maximal manual test with the KT-2000 arthrometer was 5.98mm ⫾ 2.27mm and 5.60mm ⫾ 1.32mm, respectively. In group D, it was 7.00mm ⫾ 2.20mm and 6.13mm ⫾ 1.74mm, respectively. Residual AP laxity assessed at 2 years after surgery was 1.74mm ⫾ 1.67mm and 1.79mm ⫾ 1.56mm, respectively, in group S and 1.63mm ⫾ 1.50mm and 1.61mm ⫾ 1.22mm, respectively, in group D. There were no statistically significant differences. In group S the lateral pivot-shift test was available in 38 participants. Two years after surgery, it was negative in 33 and positive in 5. In 12 cases it was not useful because of guarding by patients during examination. In group D it was available in 60 participants: 57 had negative results and 3 had positive
TABLE 1.
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Evaluation of AP and Rotational Instability at 2 Years After Surgery in Both Groups Group S
Telos stress view Preoperatively (mm) 2 yr postoperatively (mm) KT-2000 Preoperatively (mm) 2 yr postoperatively (mm) Lateral pivot-shift test 2 yr postoperatively Negative Positive
Group D
P Value
5.98 ⫾ 2.27 7.00 ⫾ 2.20 1.74 ⫾ 1.67 1.63 ⫾ 1.50
.011 .746
5.60 ⫾ 1.32 6.13 ⫾ 1.74 1.79 ⫾ 1.56 1.61 ⫾ 1.22
.153 .743 .281
33 patients 5 patients
57 patients 3 patients
results. In addition, in 3 cases it was not useful because of guarding by patients. Results of a 2 test showed no difference (Table 1). In group S the objective IKDC score preoperatively was A in 0 patients (0%), B in 3 (6.0%), C in 23 (46.0%), and D in 24 (48.0%). At 2 years postoperatively, the scores had improved, with A in 30 patients (60.0%), B in 18 (36.0%), and C in 2 (4.0%). No patients had a score of D. Group D had preoperative scores of A in 0 patients (0%), B in 5 (7.9%), C in 30 (47.6%), and D in 28 (44.4%). At 2 years after surgery, the scores had improved, with A in 47 patients (74.6%), B in 15 (23.8%), and C in 1 (1.6%). No patients had a score of D. There was no statistically significant difference between the postoperative scores in group S and group D. Although the subjective IKDC scores had increased from 56.7 ⫾ 15.5 preoperatively to 69.8 ⫾ 19.8 postoperatively in group S and from 55.5 ⫾ 18.0 to 76.8 ⫾ 15.3 in group D, the difference was not statistically significant. The Orthopadische Arbeitsgruppe Knie score had increased from 74.4 ⫾ 9.9 preoperatively to 89.4 ⫾ 7.7 postoperatively in group S and from 73.7 ⫾ 10.2 to 89.5 ⫾ 6.0 in group D, but again, the difference in this increase was not statistically significant. The Tegner activity scale at 2 years postoperatively measured 5.6 ⫾ 2.2 in group S and 5.4 ⫾ 2.0 in group D, but the difference was not statistically significant. There was no significant difference in postoperative side-to-side difference in midthigh circumference between the 2 groups, with 1.2 ⫾ 1.2 cm in group S and 1.4 ⫾ 1.1 cm in group D. For postoperative range of joint motion, a mean of 138.5° ⫾ 5.5° was observed in group S and 139.9° ⫾ 0.8° in group D, without a statistically noteworthy difference in comparison (Table 2). Superficial or intra-articular bacterial infections developed in 2 patients in group S and 2 patients in
634 TABLE 2.
S-J. PARK ET AL. Evaluation of Clinical Outcomes at 2 Years After Surgery in Both Groups Group S
Subjective IKDC score Preoperatively 56.7 ⫾ 15.5 2 yr postoperatively 69.8 ⫾ 19.8 OAK score Preoperatively 74.4 ⫾ 9.9 2 yr postoperatively 89.4 ⫾ 7.7 Tegner activity scale 2 yr postoperatively 5.6 ⫾ 2.2 Range of motion (°) Preoperatively 130.1 ⫾ 18.9 2 yr postoperatively 138.5 ⫾ 5.5 Side-to-side difference in thigh circumference (cm) Preoperatively 1.7 ⫾ 1.1 2 yr postoperatively 1.2 ⫾ 1.3
Group D
P Value
55.5 ⫾ 18.0 76.8 ⫾ 15.3
.614 .141
73.7 ⫾ 10.2 89.5 ⫾ 6.0
.943 .699
5.4 ⫾ 2.0
.679
134.9 ⫾ 13.5 139.9 ⫾ 0.8
.162 .278
1.6 ⫾ 1.1 1.4 ⫾ 1.2
.670 .393
Abbreviation: OAK, Orthopadische Arbeitsgruppe Knie.
group D, and they were treated with arthroscopic debridement and irrigation and healed without further complications. In addition, 1 patient in group D underwent arthroscopic debridement and irrigation 3 times because of infection and had revision ACL surgery at another hospital 2 years after the index operation. DISCUSSION For a more successful reconstruction of the ACL, the ideal outcome would be restoration of the original function of the ACL. However, it is already known that the ACL is composed of several bundles, each with its own characteristics. So, many surgeons try to reconstruct each bundle of the ACL separately. Several biomechanical studies have measured the ACL’s level of tension according to the range of motion of the knee joint and reported that the PL bundle carries more load in a position of terminal extension.20,21 Therefore single-bundle reconstruction of the ACL may result in AP instability in the knee position of terminal extension. In addition, the ACL is known to contribute to rotational stability; it has been reported that single-bundle reconstruction does not completely correct the rotational instability,1,6,8,22 and according to Hogervorst et al.,23 who performed a long-term observational study, single-bundle reconstruction is unable to avert degenerative alteration of the knee joint. Hence, in theory, double-bundle ACL reconstruction—the surgical procedure whose outcome more closely approximates the anatomy of the normal
ACL—is thought to yield better results than singlebundle reconstruction. However, there are still arguments about whether single-bundle or double-bundle reconstruction is better for the ACL-deficient knee. Moreover, single-bundle reconstruction of the ACL shows good clinical results over a long period of time. According to current data, some authors have reported no difference between single-bundle and double-bundle reconstruction24-26 whereas others have commented on the superiority of double-bundle reconstruction.12,27-31 For example, Yagi et al.12 stated in a comparative study of single-bundle and double-bundle reconstruction using cadavers that double-bundle reconstruction produces a better result with respect to biomechanics and shows not only AP stability but also an outstanding rotational capability. A prospective, randomized clinical study conducted by Siebold et al.29 to compare the outcome of 70 patients undergoing either 4-tunnel double-bundle or single-bundle ACL reconstruction with autogenous semitendinosus and gracilis tendon showed that anterior stability assessed by KT-1000, pivot-shift test, and objective IKDC score were significantly better in the doublebundle reconstruction group than in the single-bundle reconstruction group, but the subjective Cincinnati knee score, Lysholm score, and subjective IKDC score did not show any statistical difference between the groups. Yasuda et al.28 and Muneta et al.27 also reported significantly better anterior stability in their double-bundle ACL reconstruction groups, as well as a higher number of negative Lachman and pivot-shift tests. In a prospective, randomized clinical study, Jarvela32 reported that rotational stability evaluated by pivotshift test is better in the double-bundle reconstruction group. However, for anterior stability of the knee evaluated by KT-1000 arthrometer, there was no significant difference between groups. In contrast, a prospective, randomized study presented by Adachi et al.24 did not find any advantage of double-bundle reconstruction over single-bundle reconstruction in terms of stability or proprioception. Furthermore, Wang et al.26 reported in a prospective, randomized, controlled study that double-bundle ACL reconstruction has no obvious clinical advantage over single-bundle ACL reconstruction and the operative time for double-bundle ACL reconstruction was longer than that for single-bundle ACL reconstruction. Moreover, several meta-analyses proposed that there were no effective and valid data to support that the outcome of double-bundle reconstruction is better
SINGLE- AND DOUBLE-BUNDLE ACL RECONSTRUCTION than that of single-bundle reconstruction with respect to rotational stability.15-17 Several studies investigating the double-bundle reconstruction method have also been reported or are currently being performed. Among these methodologic studies, one controversy has been about the number of tunnels in the femur and the tibia, and Edwards et al.33 stated that the total of 2 tunnels in both the femur and the tibia was the most efficient method. Until recently, to compensate for the disadvantage of single-bundle reconstruction, the graft has been inclined so that it would be located more horizontally. In this study we also placed the graft more horizontally (10-o’clock position) during single-bundle reconstruction. To compensate for the difference in quality of allograft, this study only used autogenous hamstring tendon, and we found no fault in either the thickness or the length of the autograft, which we have constructed using semitendinosus tendon and gracilis tendon extracted from the uninjured knee and folding them into 3 layers. The hamstring tendon was harvested from the patient’s normal-functioning limb on the opposite side of injury because of the possibility of tendon extraction affecting rotational instability. In this study we preferred the RigidFix system for AM bundle fixation at the femoral side over the EndoButton to escape tunnel widening. Comparison of the preoperative and postoperative results of groups S and D showed that there were no significant differences in the results. The AP stability test measured with the telos device and KT-2000 2 years after surgery indicated that group D had remaining instability of 1.63mm ⫾ 1.50mm and 1.61mm ⫾ 1.22mm, respectively, whereas group S showed 1.74mm ⫾ 1.67mm and 1.79mm ⫾ 1.56mm, respectively. Although stability in group D was better than in group S, there was no statistical difference. In addition, we were unable to confirm a statistically significant difference in any of the other test results such as the lateral pivot-shift test. In our opinion, there are several reasons why the double-bundle ACL reconstruction does not produce a better clinical outcome. First, there is the lack of an isometric point of the PL bundle of the ACL. So, the PL bundle showed more excursion when cyclic loading was performed during surgery. Second, mistakes are common regarding tunnel position with the double-bundle technique. Especially with the transtibial tunnel technique, there is some difficulty in obtaining the correct femoral anatomic position for the PL bundle.34,35 As a result, Giron et al.36 insisted on improve-
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ment in femoral-side tunnel positioning for doublebundle ACL reconstruction with the transtibial technique. Recently, we have been using an accessory low AM portal instead of the transtibial tunnel technique to obtain a more horizontal position of the femoral tunnel. In addition, postoperative rehabilitation may have played a role in the results. Because there are no specific rehabilitation protocols for the PL bundle, it is impossible to accelerate rehabilitation like the single-bundle reconstruction group. This study has some limitations. We currently lack an adequate method to quantitatively measure rotational instability using anatomic or radiologic tests. In this study a lateral pivot-shift test was used, but this is a subjective test and it requires the patient’s cooperation. Another limitation is that we failed to evaluate the characteristic proprioceptive function thought to be one of the merits of double-bundle reconstruction. In addition, there is the lack of a power analysis because of the small number of cases. Therefore a more successful ACL reconstruction demands more research regarding surgical technique and assessment procedures regarding postoperative results and would entail more cases, confirmation, and long-term observational studies. CONCLUSIONS We found that double-bundle reconstruction of the ACL using 2 tibial tunnels and 2 femoral tunnels showed no differences in stability results or any other clinical aspects or in terms of patient satisfaction. So, our study does not support the hypothesis that doublebundle ACL reconstruction would be advantageous in restoring anterior and rotational stability, as well as providing better objective clinical results, compared with single-bundle reconstruction. REFERENCES 1. Freedman KB, D’Amato MJ, Nedeff DD, Kaz A, Bach BR Jr. Arthroscopic anterior cruciate ligament reconstruction: A metaanalysis comparing patellar tendon and hamstring tendon autografts. Am J Sports Med 2003;31:2-11. 2. Gobbi A, Mahajan S, Zanazzo M, Tuy B. Patellar tendon versus quadrupled bone-semitendinosus anterior cruciate ligament reconstruction: A prospective clinical investigation in athletes. Arthroscopy 2003;19:592-601. 3. Chen CH, Chuang TY, Wang KC, Chen WJ, Shih CH. Arthroscopic anterior cruciate ligament reconstruction with quadriceps tendon autograft: Clinical outcome in 4-7 years. Knee Surg Sports Traumatol Arthrosc 2006;14:1077-1085. 4. Siebold R, Webster KE, Feller JA, Sutherland AG, Elliott J. Anterior cruciate ligament reconstruction in females: A com-
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parison of hamstring tendon and patellar tendon autografts. Knee Surg Sports Traumatol Arthrosc 2006;14:1070-1076. Harner CD, Giffin JR, Dunteman RC, Annunziata CC, Friedman MJ. Evaluation and treatment of recurrent instability after anterior cruciate ligament reconstruction. Instr Course Lect 2001;50:463-474. Aglietti P, Giron F, Buzzi R, Biddau F, Sasso F. Anterior cruciate ligament reconstruction: Bone-patellar tendon-bone compared with double semitendinosus and gracilis tendon grafts. A prospective, randomized clinical trial. J Bone Joint Surg Am 2004;86:2143-2155. Zelle BA, Vidal AF, Brucker PU, Fu FH. Double-bundle reconstruction of the anterior cruciate ligament: Anatomic and biomechanical rationale. J Am Acad Orthop Surg 2007;15:87-96. Girgis FG, Marshall JL, Monajem A. The cruciate ligaments of the knee joint. Anatomical, functional and experimental analysis. Clin Orthop Relat Res 1975:216-231. Amis AA, Dawkins GP. Functional anatomy of the anterior cruciate ligament. Fibre bundle actions related to ligament replacements and injuries. J Bone Joint Surg Br 1991;73:260267. Mochizuki T, Muneta T, Nagase T, Shirasawa S, Akita KI, Sekiya I. Cadaveric knee observation study for describing anatomic femoral tunnel placement for two-bundle anterior cruciate ligament reconstruction. Arthroscopy 2006;22:356361. Mae T, Shino K, Miyama T, et al. Single- versus two-femoral socket anterior cruciate ligament reconstruction technique: Biomechanical analysis using a robotic simulator. Arthroscopy 2001;17:708-716. Yagi M, Wong EK, Kanamori A, Debski RE, Fu FH, Woo SL. Biomechanical analysis of an anatomic anterior cruciate ligament reconstruction. Am J Sports Med 2002;30:660-666. Shen W, Jordan S, Fu F. Review article: Anatomic double bundle anterior cruciate ligament reconstruction. J Orthop Surg (Hong Kong) 2007;15:216-221. Gadikota HR, Seon JK, Kozanek M, et al. Biomechanical comparison of single-tunnel-double-bundle and single-bundle anterior cruciate ligament reconstructions. Am J Sports Med 2009;37:962-969. Lewis PB, Parameswaran AD, Rue JP, Bach BR Jr. Systematic review of single-bundle anterior cruciate ligament reconstruction outcomes: A baseline assessment for consideration of double-bundle techniques. Am J Sports Med 2008;36:20282036. Longo UG, King JB, Denaro V, Maffulli N. Double-bundle arthroscopic reconstruction of the anterior cruciate ligament: Does the evidence add up? J Bone Joint Surg Br 2008;90:995999. Meredick RB, Vance KJ, Appleby D, Lubowitz JH. Outcome of single-bundle versus double-bundle reconstruction of the anterior cruciate ligament: A meta-analysis. Am J Sports Med 2008;36:1414-1421. Yasuda K, Kondo E, Ichiyama H, et al. Anatomic reconstruction of the anteromedial and posterolateral bundles of the anterior cruciate ligament using hamstring tendon grafts. Arthroscopy 2004;20:1015-1025. Baumfeld JA, Diduch DR, Rubino LJ, et al. Tunnel widening following anterior cruciate ligament reconstruction using hamstring autograft: A comparison between double cross-pin and suspensory graft fixation. Knee Surg Sports Traumatol Arthrosc 2008;16:1108-1113. Sakane M, Fox RJ, Woo SL, Livesay GA, Li G, Fu FH. In situ forces in the anterior cruciate ligament and its bundles in response to anterior tibial loads. J Orthop Res 1997;15:285293.
21. Zantop T, Herbort M, Raschke MJ, Fu FH, Petersen W. The role of the anteromedial and posterolateral bundles of the anterior cruciate ligament in anterior tibial translation and internal rotation. Am J Sports Med 2007;35:223-227. 22. Chhabra A, Starman JS, Ferretti M, Vidal AF, Zantop T, Fu FH. Anatomic, radiographic, biomechanical, and kinematic evaluation of the anterior cruciate ligament and its two functional bundles. J Bone Joint Surg Am 2006;88:2-10 (Suppl 4). 23. Hogervorst T, Pels Rijcken TH, Rucker D, van der Hart CP, Taconis WK. Changes in bone scans after anterior cruciate ligament reconstruction: A prospective study. Am J Sports Med 2002;30:823-833. 24. Adachi N, Ochi M, Uchio Y, Iwasa J, Kuriwaka M, Ito Y. Reconstruction of the anterior cruciate ligament. Single- versus double-bundle multistranded hamstring tendons. J Bone Joint Surg Br 2004;86:515-520. 25. Markolf KL, Park S, Jackson SR, McAllister DR. Simulated pivot-shift testing with single and double-bundle anterior cruciate ligament reconstructions. J Bone Joint Surg Am 2008;90: 1681-1689. 26. Wang JQ, Ao YF, Yu CL, Liu P, Xu Y, Chen LX. Clinical evaluation of double-bundle anterior cruciate ligament reconstruction procedure using hamstring tendon grafts: A prospective, randomized and controlled study. Chin Med J (Engl) 2009;122:706-711. 27. Muneta T, Koga H, Morito T, Yagishita K, Sekiya I. A retrospective study of the midterm outcome of two-bundle anterior cruciate ligament reconstruction using quadrupled semitendinosus tendon in comparison with one-bundle reconstruction. Arthroscopy 2006;22:252-258. 28. Yasuda K, Kondo E, Ichiyama H, Tanabe Y, Tohyama H. Clinical evaluation of anatomic double-bundle anterior cruciate ligament reconstruction procedure using hamstring tendon grafts: Comparisons among 3 different procedures. Arthroscopy 2006;22:240-251. 29. Siebold R, Dehler C, Ellert T. Prospective randomized comparison of double-bundle versus single-bundle anterior cruciate ligament reconstruction. Arthroscopy 2008;24:137-145. 30. Fu FH, Shen W, Starman JS, Okeke N, Irrgang JJ. Primary anatomic double-bundle anterior cruciate ligament reconstruction: A preliminary 2-year prospective study. Am J Sports Med 2008;36:1263-1274. 31. Kim SJ, Jo SB, Kumar P, Oh KS. Comparison of single- and double-bundle anterior cruciate ligament reconstruction using quadriceps tendon-bone autografts. Arthroscopy 2009;25:70-77. 32. Jarvela T. Double-bundle versus single-bundle anterior cruciate ligament reconstruction: A prospective, randomize clinical study. Knee Surg Sports Traumatol Arthrosc 2007;15:500507. 33. Edwards TB, Guanche CA, Petrie SG, Thomas KA. In vitro comparison of elongation of the anterior cruciate ligament and single- and dual-tunnel anterior cruciate ligament reconstructions. Orthopedics 1999;22:577-584. 34. Lubowitz JH. Anteromedial portal technique for the anterior cruciate ligament femoral socket: Pitfalls and solutions. Arthroscopy 2009;25:95-101. 35. Dargel J, Schmidt-Wiethoff R, Fischer S, Mader K, Koebke J, Schneider T. Femoral bone tunnel placement using the transtibial tunnel or the anteromedial portal in ACL reconstruction: A radiographic evaluation. Knee Surg Sports Traumatol Arthrosc 2009;17:220-227. 36. Giron F, Cuomo P, Edwards A, Bull AM, Amis AA, Aglietti P. Double-bundle “anatomic” anterior cruciate ligament reconstruction: A cadaveric study of tunnel positioning with a transtibial technique. Arthroscopy 2007;23:7-13.
Purpose: The purpose of this study was to compare the clinical results of arthroscopic single-bundle and double-bundle anterior cruciate ligament (ACL) reconstruction. Methods: We designed a prospective study that included patients with an isolated ACL injury. From April 2004 to February 2007, of 147 patients who underwent ACL reconstruction, 113 were included in this study. We serially obtained clinical and radiologic data preoperatively and postoperatively. We compared preoperative data and data at 2 years postoperatively in patients who had undergone single-bundle ACL reconstruction versus patients who had undergone double-bundle ACL reconstruction. There were 50 single-bundle reconstructions and 63 double-bundle reconstructions. Anteroposterior stability was assessed objectively by anterior stress radiographs with the telos device (telos, Marburg, Germany) and the maximal manual test with the KT-2000 arthrometer (MEDmetric, San Diego, CA). Rotational stability was determined by lateral pivot-shift test. The clinical results were assessed by International Knee Documentation Committee and Orthopadische Arbeitsgruppe Knie scores and Tegner activity scale. In addition, we evaluated postoperative thigh circumference and range of motion. Results: Residual anteroposterior laxity determined at 2 years postoperatively by telos and KT-2000 was 1.74mm ⫾ 1.67mm and 1.79mm ⫾ 1.56mm, respectively, in the single-bundle reconstruction group and 1.63mm ⫾ 1.50mm and 1.61mm ⫾ 1.22mm, respectively, in the doublebundle reconstruction group. There were no statistically significant differences. For the lateral pivot-shift test done at 2 years postoperatively, there was no statistically significant difference. In addition, clinical results such as International Knee Documentation Committee score, Orthopadische Arbeitsgruppe Knie score, Tegner activity scale, thigh circumference, and range of motion showed no significant differences between the 2 groups. Conclusions: Double-bundle reconstruction of the ACL by a method using 2 femoral tunnel and 2 tibial tunnels showed no differences in stability results or any other clinical aspects or in terms of patient satisfaction. Level of Evidence: Level II, prospective comparative study.
From the Department of Orthopedic Surgery, School of Medicine, Kangbuk Samsung Hospital, Sungkyunkwan University (S-J.P., H-J.J., H.K.S., E.K., G-S.K.); Knee Center, Department of Orthopedic Surgery, Chung-Ang University Hospital (Y-B.J., H-J.J., K-S.S., H-Y.C.); and Biostatistics Team, Samsung Biomechanical Research Institute (S.K.), Seoul, South Korea. The authors report no conflict of interest. Received December 29, 2008; accepted September 9, 2009. Address correspondence and reprint requests to Young-Bok Jung, M.D., Knee Center, Department of Orthopaedic Surgery, Chung-Ang University Hospital, 224-1, Heukseok-dong, Dongjak-gu, 156-755, Seoul, South Korea. E-mail: [email protected] © 2010 by the Arthroscopy Association of North America 0749-8063/10/2605-8724$36.00/0 doi:10.1016/j.arthro.2009.09.006
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Arthroscopy: The Journal of Arthroscopic and Related Surgery, Vol 26, No 5 (May), 2010: pp 630-636
SINGLE- AND DOUBLE-BUNDLE ACL RECONSTRUCTION
R
econstruction of the anterior cruciate ligament (ACL) is the most frequently performed reconstructive surgery in the knee. To date, the most widely attempted technique, and thus the gold standard for ACL reconstruction, has been arthroscopic singlebundle reconstruction.1-4 Single-bundle ACL reconstructions have provided excellent success rates of over 80%, but some authors have noted residual instability and patient dissatisfaction after surgery.5-7 Several anatomic studies have shown that the ACL consists of 2 major functional bundles: anteromedial (AM) and posterolateral (PL).8,9 Each bundle has distinct and complementary roles. In knee extension the PL bundle is tight and the AM bundle is loose. As the knee flexes, the AM bundle becomes tight and the PL bundle becomes lax. In addition, the PL bundle is more responsible for rotational stability.10 Several biomechanical studies suggest that double-bundle ACL reconstruction has advantages in terms of both anterior knee stability and rotational stability in the ACL-deficient knee compared with single-bundle ACL reconstruction.11-14 So, currently, there is more focus on double-bundle ACL reconstruction than single-bundle reconstruction. Even though such anatomic studies and biomechanical studies support the basis of double-bundle ACL reconstruction, there are still disputes about the results of single-bundle versus double-bundle reconstruction of the ACL. Furthermore, several meta-analysis studies have shown that double-bundle ACL reconstruction does not result in significant differences compared with single-bundle reconstruction.15-17 The purpose of this study was to evaluate the clinical outcome of arthroscopic double-bundle ACL reconstruction compared with that of single-bundle ACL reconstruction in a prospective, randomized clinical study. We hypothesized that double-bundle ACL reconstruction with hamstring tendon autograft using 2 tibial tunnels and 2 femoral tunnels would be advantageous in restoring anterior and rotational stability, as well as providing better objective clinical results, compared with single-bundle reconstruction. METHODS From April 2004 to February 2007, 147 consecutive ACL reconstruction surgeries were performed by the senior surgeon according to a prospective study design. Inclusion criteria were primary ACL reconstruction with no combined posterior cruciate ligament injury, lateral collateral ligament injury, PL rotatory instability, or fracture around knee; no previous knee
631
ligament surgery; no arthritic changes; no subtotal or total meniscectomy; no malalignment; and a normal contralateral knee. In cases of combined acute medial collateral injuries, ACL reconstruction was done after appropriate conservative treatment for 2 weeks with a long leg splint and then another 4 weeks with a brace and confirmation of good stability of the medial collateral ligament by physical examination. None of the participants had undergone reconstruction of the medial collateral ligament. Patients were excluded from the study when the examination under anesthesia or intraoperative findings did not meet the previously mentioned inclusion criteria. Patients were sequentially selected to undergo either single-bundle or double-bundle reconstruction based on order of admittance to our hospital. Of the 147 cases, 121 were found to have met our inclusion criteria. However, 7 cases did not undergo follow-up within 2 years after surgery, and 1 case was omitted because revision ACL surgery was performed after postoperative infection developed. Of the 113 patients, 50 comprised the single-bundle reconstruction group (group S) and 63 comprised the double-bundle reconstruction group (group D). Group S patients (34 males and 16 females) were aged between 16 and 54 years, with a mean of 28.3 years, and group D patients (48 males and 15 females) were aged between 17 and 57 years, with a mean of 29.6 years. Regarding corresponding injuries to the ACL, there were 12 patients with medial meniscus tear, 10 with lateral meniscus tear, 5 with medial collateral ligament injury, and 4 with osteochondral defect in group S. In group D there were 15 patients with medial meniscus tear, 13 with lateral meniscus tear, 9 with medial collateral ligament injury, and 8 with osteochondral defect. The patient’s condition was investigated during physician’s office visits preoperatively and at 3, 6, 12, and 24 months postoperatively, and we used preoperative data and data at 2 years postoperatively to analyze and compare surgical results. Objective assessment of anteroposterior (AP) stability was performed by use of radiographs with the telos device (telos, Marburg, Germany) and KT-2000 arthrometer (MEDmetric, San Diego, CA), and rotational instability was assessed by lateral pivot-shift test and clinical results by International Knee Documentation Committee (IKDC) score, Orthopadische Arbeitsgruppe Knie score, and Tegner activity scale. The postoperative physical examination was performed by a specially trained physician assistant in our orthopaedic department. Stress radiographs obtained with the telos device were taken with knee flexion at 90°. We also measured active range of
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motion with a goniometer. In addition, postoperative thigh circumference was measured at 10 cm above the upper pole of the patella with full extension of the knee. The hamstring tendon was harvested from the patient’s normal-functioning limb on the opposite side of injury because of the possibility of tendon extraction affecting rotational instability. Wilcoxon rank sum test and Mann-Whitney U test were used for statistical analysis, and P ⬍ .05 was determined to be statistically significant. The telos stress test and KT-2000 arthrometer test, which were evaluated at 2 years postoperatively, were defined as primary parameters. To detect the minimal clinically meaningful difference of 1.0 in the primary parameters between the 2 groups, this study has a power of 86% given the study sample size and the SDs of the data under a significance level of .05. So, the reason for no significance was not that the study was underpowered; rather, the reason was the small difference between the 2 groups. Surgical Technique of Single-Bundle ACL Reconstruction In a single-bundle reconstruction of the ACL, traditional AM bundle reconstruction with arthroscopy was done with both semitendinosus tendon and gracilis tendon, with each segment folded in half to form a quadruple-thickness replacement graft. First, the tibial tunnel was drilled at a 50° angle in the horizontal plane and approximately 2 cm medial from tibial tuberosity in the sagittal plane. The femoral tunnel was made in the femoral notch positioned at 10 o’clock (right knee) or 2 o’clock (left knee) through a transtibial technique. After insertion of an offset guide through the tibial tunnel at knee flexion of 70° to 80°, a guide pin was inserted into the lateral femoral condyle to a depth of approximately 30 mm. Then, with the knee flexed 90°, a guide pin was inserted completely. Notchplasty was not used. We used the RigidFix system (DePuy Mitek, Raynham, MA) for femoral fixation and bioabsorbable interference screws with an Intrafix technique (DePuy Mitek) for tibial fixation. Surgical Technique of Double-Bundle ACL Reconstruction After extracting the hamstring tendon autografts on the AM side of the uninjured proximal tibia, we assembled the extracted autografts from the semitendinosus tendon into a 3-stranded graft used for AM bundle reconstruction and from the gracilis tendon
FIGURE 1.
Hamstring tendon autograft.
into a 3-stranded graft used for PL bundle reconstruction (Fig 1). We used the 2–femoral tunnel and 2–tibial tunnel technique to reconstruct the double-bundle ACL. After confirmation of the ACL attachment site, a tibial tunnel for the PL bundle, a tibial tunnel for the AM bundle, a femoral tunnel for the PL bundle, and a femoral tunnel for the AM bundle were made one by one. Tunnel placement for ACL reconstruction of both bundles was done according to Yasuda et al.18 The femoral tunnel for the AM bundle was located at the 10:30 (right knee) or 1:30 (left knee) position with respect to the intercondylar area. We used caution to avoid impingement of the roof and posterior cruciate ligament with the reconstructed ACL by trying to direct the tibial tunnel into the axis of the normal ACL, ensuring that the graft was not positioned vertically. In addition, we attempted to prevent friction in the anterior intercondylar area of the inner joint when the knee joint was fully extended by inserting the AM guide pin 2 to 3 mm posterior to the anterior margin of the intercondylar notch. To fix the grafts in the femoral tunnel, the RigidFix system was used for the AM bundle and an EndoButton (Smith & Nephew Endoscopy, Andover, MA) was used for the PL bundle. Because a cortical suspensory fixation with the EndoButton can cause some complications such as bone tunnel widening, and both tunnels for the AM and PL bundles might be put together, we prefer the RigidFix system to the EndoButton for AM bundle fixation.19 The 3-stranded autografts from the semitendinosus tendon were long and thick enough for use with the RigidFix system. During this process, the direction of the RigidFix system must be checked so that it does not transit through the PL bundle.
SINGLE- AND DOUBLE-BUNDLE ACL RECONSTRUCTION No. 5 Ethibond (Ethicon, Somerville, NJ) used at the end of each tendon for suturing of each graft was connected to the measuring device to determine the tension level; the measuring device was pulled with a 10- to 15-lb force as the knee joint underwent cyclic loading at 0° to 90° for 20 cycles. Then, a bioabsorbable screw was inserted through the AM tibial tunnel with a 15-lb tension at 30° of flexion of the knee joint. The PL bundle was also fixed with a bioabsorbable screw under a 10-lb tension at a 5° to 10° flexion angle. During this process, if the length of the graft was too short to use the bioabsorbable screw, a screw with a thickness of 6.5 mm and a washer were used to perform the post tie. During fixation of the PL bundle, there was excursion of the PL bundle graft measuring a few millimeters in most of the patients. After confirmation of full extension of the knee joint and no friction in the anterior intercondylar area, the tension of each graft tendon was assessed with an arthroscopic probe. Rehabilitation With respect to postoperative rehabilitation, the protocol was identical for both groups. For the first 6 weeks, walking with crutches with partial weight bearing was allowed without any brace or splint. Patients were encouraged to restore full extension of the knee joint and strengthen the quadriceps muscle power. Six weeks after surgery, patients returned to performing activities of daily living. Noncontact sports were permitted after 3 months, and contact sports were permitted 1 year after surgery. RESULTS In group S preoperative AP instability as determined with the telos device and maximal manual test with the KT-2000 arthrometer was 5.98mm ⫾ 2.27mm and 5.60mm ⫾ 1.32mm, respectively. In group D, it was 7.00mm ⫾ 2.20mm and 6.13mm ⫾ 1.74mm, respectively. Residual AP laxity assessed at 2 years after surgery was 1.74mm ⫾ 1.67mm and 1.79mm ⫾ 1.56mm, respectively, in group S and 1.63mm ⫾ 1.50mm and 1.61mm ⫾ 1.22mm, respectively, in group D. There were no statistically significant differences. In group S the lateral pivot-shift test was available in 38 participants. Two years after surgery, it was negative in 33 and positive in 5. In 12 cases it was not useful because of guarding by patients during examination. In group D it was available in 60 participants: 57 had negative results and 3 had positive
TABLE 1.
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Evaluation of AP and Rotational Instability at 2 Years After Surgery in Both Groups Group S
Telos stress view Preoperatively (mm) 2 yr postoperatively (mm) KT-2000 Preoperatively (mm) 2 yr postoperatively (mm) Lateral pivot-shift test 2 yr postoperatively Negative Positive
Group D
P Value
5.98 ⫾ 2.27 7.00 ⫾ 2.20 1.74 ⫾ 1.67 1.63 ⫾ 1.50
.011 .746
5.60 ⫾ 1.32 6.13 ⫾ 1.74 1.79 ⫾ 1.56 1.61 ⫾ 1.22
.153 .743 .281
33 patients 5 patients
57 patients 3 patients
results. In addition, in 3 cases it was not useful because of guarding by patients. Results of a 2 test showed no difference (Table 1). In group S the objective IKDC score preoperatively was A in 0 patients (0%), B in 3 (6.0%), C in 23 (46.0%), and D in 24 (48.0%). At 2 years postoperatively, the scores had improved, with A in 30 patients (60.0%), B in 18 (36.0%), and C in 2 (4.0%). No patients had a score of D. Group D had preoperative scores of A in 0 patients (0%), B in 5 (7.9%), C in 30 (47.6%), and D in 28 (44.4%). At 2 years after surgery, the scores had improved, with A in 47 patients (74.6%), B in 15 (23.8%), and C in 1 (1.6%). No patients had a score of D. There was no statistically significant difference between the postoperative scores in group S and group D. Although the subjective IKDC scores had increased from 56.7 ⫾ 15.5 preoperatively to 69.8 ⫾ 19.8 postoperatively in group S and from 55.5 ⫾ 18.0 to 76.8 ⫾ 15.3 in group D, the difference was not statistically significant. The Orthopadische Arbeitsgruppe Knie score had increased from 74.4 ⫾ 9.9 preoperatively to 89.4 ⫾ 7.7 postoperatively in group S and from 73.7 ⫾ 10.2 to 89.5 ⫾ 6.0 in group D, but again, the difference in this increase was not statistically significant. The Tegner activity scale at 2 years postoperatively measured 5.6 ⫾ 2.2 in group S and 5.4 ⫾ 2.0 in group D, but the difference was not statistically significant. There was no significant difference in postoperative side-to-side difference in midthigh circumference between the 2 groups, with 1.2 ⫾ 1.2 cm in group S and 1.4 ⫾ 1.1 cm in group D. For postoperative range of joint motion, a mean of 138.5° ⫾ 5.5° was observed in group S and 139.9° ⫾ 0.8° in group D, without a statistically noteworthy difference in comparison (Table 2). Superficial or intra-articular bacterial infections developed in 2 patients in group S and 2 patients in
634 TABLE 2.
S-J. PARK ET AL. Evaluation of Clinical Outcomes at 2 Years After Surgery in Both Groups Group S
Subjective IKDC score Preoperatively 56.7 ⫾ 15.5 2 yr postoperatively 69.8 ⫾ 19.8 OAK score Preoperatively 74.4 ⫾ 9.9 2 yr postoperatively 89.4 ⫾ 7.7 Tegner activity scale 2 yr postoperatively 5.6 ⫾ 2.2 Range of motion (°) Preoperatively 130.1 ⫾ 18.9 2 yr postoperatively 138.5 ⫾ 5.5 Side-to-side difference in thigh circumference (cm) Preoperatively 1.7 ⫾ 1.1 2 yr postoperatively 1.2 ⫾ 1.3
Group D
P Value
55.5 ⫾ 18.0 76.8 ⫾ 15.3
.614 .141
73.7 ⫾ 10.2 89.5 ⫾ 6.0
.943 .699
5.4 ⫾ 2.0
.679
134.9 ⫾ 13.5 139.9 ⫾ 0.8
.162 .278
1.6 ⫾ 1.1 1.4 ⫾ 1.2
.670 .393
Abbreviation: OAK, Orthopadische Arbeitsgruppe Knie.
group D, and they were treated with arthroscopic debridement and irrigation and healed without further complications. In addition, 1 patient in group D underwent arthroscopic debridement and irrigation 3 times because of infection and had revision ACL surgery at another hospital 2 years after the index operation. DISCUSSION For a more successful reconstruction of the ACL, the ideal outcome would be restoration of the original function of the ACL. However, it is already known that the ACL is composed of several bundles, each with its own characteristics. So, many surgeons try to reconstruct each bundle of the ACL separately. Several biomechanical studies have measured the ACL’s level of tension according to the range of motion of the knee joint and reported that the PL bundle carries more load in a position of terminal extension.20,21 Therefore single-bundle reconstruction of the ACL may result in AP instability in the knee position of terminal extension. In addition, the ACL is known to contribute to rotational stability; it has been reported that single-bundle reconstruction does not completely correct the rotational instability,1,6,8,22 and according to Hogervorst et al.,23 who performed a long-term observational study, single-bundle reconstruction is unable to avert degenerative alteration of the knee joint. Hence, in theory, double-bundle ACL reconstruction—the surgical procedure whose outcome more closely approximates the anatomy of the normal
ACL—is thought to yield better results than singlebundle reconstruction. However, there are still arguments about whether single-bundle or double-bundle reconstruction is better for the ACL-deficient knee. Moreover, single-bundle reconstruction of the ACL shows good clinical results over a long period of time. According to current data, some authors have reported no difference between single-bundle and double-bundle reconstruction24-26 whereas others have commented on the superiority of double-bundle reconstruction.12,27-31 For example, Yagi et al.12 stated in a comparative study of single-bundle and double-bundle reconstruction using cadavers that double-bundle reconstruction produces a better result with respect to biomechanics and shows not only AP stability but also an outstanding rotational capability. A prospective, randomized clinical study conducted by Siebold et al.29 to compare the outcome of 70 patients undergoing either 4-tunnel double-bundle or single-bundle ACL reconstruction with autogenous semitendinosus and gracilis tendon showed that anterior stability assessed by KT-1000, pivot-shift test, and objective IKDC score were significantly better in the doublebundle reconstruction group than in the single-bundle reconstruction group, but the subjective Cincinnati knee score, Lysholm score, and subjective IKDC score did not show any statistical difference between the groups. Yasuda et al.28 and Muneta et al.27 also reported significantly better anterior stability in their double-bundle ACL reconstruction groups, as well as a higher number of negative Lachman and pivot-shift tests. In a prospective, randomized clinical study, Jarvela32 reported that rotational stability evaluated by pivotshift test is better in the double-bundle reconstruction group. However, for anterior stability of the knee evaluated by KT-1000 arthrometer, there was no significant difference between groups. In contrast, a prospective, randomized study presented by Adachi et al.24 did not find any advantage of double-bundle reconstruction over single-bundle reconstruction in terms of stability or proprioception. Furthermore, Wang et al.26 reported in a prospective, randomized, controlled study that double-bundle ACL reconstruction has no obvious clinical advantage over single-bundle ACL reconstruction and the operative time for double-bundle ACL reconstruction was longer than that for single-bundle ACL reconstruction. Moreover, several meta-analyses proposed that there were no effective and valid data to support that the outcome of double-bundle reconstruction is better
SINGLE- AND DOUBLE-BUNDLE ACL RECONSTRUCTION than that of single-bundle reconstruction with respect to rotational stability.15-17 Several studies investigating the double-bundle reconstruction method have also been reported or are currently being performed. Among these methodologic studies, one controversy has been about the number of tunnels in the femur and the tibia, and Edwards et al.33 stated that the total of 2 tunnels in both the femur and the tibia was the most efficient method. Until recently, to compensate for the disadvantage of single-bundle reconstruction, the graft has been inclined so that it would be located more horizontally. In this study we also placed the graft more horizontally (10-o’clock position) during single-bundle reconstruction. To compensate for the difference in quality of allograft, this study only used autogenous hamstring tendon, and we found no fault in either the thickness or the length of the autograft, which we have constructed using semitendinosus tendon and gracilis tendon extracted from the uninjured knee and folding them into 3 layers. The hamstring tendon was harvested from the patient’s normal-functioning limb on the opposite side of injury because of the possibility of tendon extraction affecting rotational instability. In this study we preferred the RigidFix system for AM bundle fixation at the femoral side over the EndoButton to escape tunnel widening. Comparison of the preoperative and postoperative results of groups S and D showed that there were no significant differences in the results. The AP stability test measured with the telos device and KT-2000 2 years after surgery indicated that group D had remaining instability of 1.63mm ⫾ 1.50mm and 1.61mm ⫾ 1.22mm, respectively, whereas group S showed 1.74mm ⫾ 1.67mm and 1.79mm ⫾ 1.56mm, respectively. Although stability in group D was better than in group S, there was no statistical difference. In addition, we were unable to confirm a statistically significant difference in any of the other test results such as the lateral pivot-shift test. In our opinion, there are several reasons why the double-bundle ACL reconstruction does not produce a better clinical outcome. First, there is the lack of an isometric point of the PL bundle of the ACL. So, the PL bundle showed more excursion when cyclic loading was performed during surgery. Second, mistakes are common regarding tunnel position with the double-bundle technique. Especially with the transtibial tunnel technique, there is some difficulty in obtaining the correct femoral anatomic position for the PL bundle.34,35 As a result, Giron et al.36 insisted on improve-
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ment in femoral-side tunnel positioning for doublebundle ACL reconstruction with the transtibial technique. Recently, we have been using an accessory low AM portal instead of the transtibial tunnel technique to obtain a more horizontal position of the femoral tunnel. In addition, postoperative rehabilitation may have played a role in the results. Because there are no specific rehabilitation protocols for the PL bundle, it is impossible to accelerate rehabilitation like the single-bundle reconstruction group. This study has some limitations. We currently lack an adequate method to quantitatively measure rotational instability using anatomic or radiologic tests. In this study a lateral pivot-shift test was used, but this is a subjective test and it requires the patient’s cooperation. Another limitation is that we failed to evaluate the characteristic proprioceptive function thought to be one of the merits of double-bundle reconstruction. In addition, there is the lack of a power analysis because of the small number of cases. Therefore a more successful ACL reconstruction demands more research regarding surgical technique and assessment procedures regarding postoperative results and would entail more cases, confirmation, and long-term observational studies. CONCLUSIONS We found that double-bundle reconstruction of the ACL using 2 tibial tunnels and 2 femoral tunnels showed no differences in stability results or any other clinical aspects or in terms of patient satisfaction. So, our study does not support the hypothesis that doublebundle ACL reconstruction would be advantageous in restoring anterior and rotational stability, as well as providing better objective clinical results, compared with single-bundle reconstruction. REFERENCES 1. Freedman KB, D’Amato MJ, Nedeff DD, Kaz A, Bach BR Jr. Arthroscopic anterior cruciate ligament reconstruction: A metaanalysis comparing patellar tendon and hamstring tendon autografts. Am J Sports Med 2003;31:2-11. 2. Gobbi A, Mahajan S, Zanazzo M, Tuy B. Patellar tendon versus quadrupled bone-semitendinosus anterior cruciate ligament reconstruction: A prospective clinical investigation in athletes. Arthroscopy 2003;19:592-601. 3. Chen CH, Chuang TY, Wang KC, Chen WJ, Shih CH. Arthroscopic anterior cruciate ligament reconstruction with quadriceps tendon autograft: Clinical outcome in 4-7 years. Knee Surg Sports Traumatol Arthrosc 2006;14:1077-1085. 4. Siebold R, Webster KE, Feller JA, Sutherland AG, Elliott J. Anterior cruciate ligament reconstruction in females: A com-
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