Bone patellar tendon bone autograft versus LARS artificial ligament for anterior cruciate ligament reconstruction

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1 Eur J Orthop Surg Traumatol (2013) 23: DOI /s ORIGINAL ARTICLE Bone patellar tendon bone autograft versus LARS artificial ligament for anterior cruciate ligament reconstruction Xiaoyun Pan Hong Wen Lide Wang Tichi Ge Received: 24 April 2012 / Accepted: 20 August 2012 / Published online: 19 September 2012 Ó Springer-Verlag 2012 Abstract The optimized graft for use in anterior cruciate ligament (ACL) reconstruction is still in controversy. The bone patellar tendon bone (BPTB) autograft has been accepted as the gold standard for ACL reconstruction. However, donor site morbidities cannot be avoided after this treatment. The artificial ligament of ligament advanced reinforcement system (LARS) has been recommended for ACL reconstruction. The purpose of this study is to compare the midterm outcome of ACL reconstruction using BPTB autografts or LARS ligaments. Between July 2004 and March 2006, the ACL reconstruction using BPTB autografts in 30 patients and LARS ligaments in 32 patients was performed. All patients were followed up for at least 4 years and evaluated using the Lysholm knee score, Tegner score, International Knee Documentation Committee (IKDC) score, and KT-1000 arthrometer test. There were no significant differences between the two groups with respect to the data of Lysholm scores, Tegner scores, IKDC scores, and KT-1000 arthrometer test at the latest follow-up. Our study demonstrates that the similarly good clinical results are obtained after ACL reconstruction X. Pan H. Wen Orthopaedic Department, The Second Affiliated Hospital of Wenzhou Medical College, Wenzhou , Zhejiang Province, People s Republic of China L. Wang Orthopaedic Department, The First Affiliated Hospital of Dalian Medical University, Dalian , Liaoning Province, People s Republic of China T. Ge (&) Emergency Department, The Third Affiliated Hospital of Wenzhou Medical College, No.108 Wansong Road, RuiAn , Zhejiang Province, People s Republic of China tichige@126.com using BPTB autografts or LARS ligaments at midterm follow-up. In addition to BPTB autografts, the LARS ligament may be a satisfactory treatment option for ACL rupture. Keywords Anterior cruciate ligament reconstruction Autograft Artificial ligament Ligament advanced reinforcement system Introduction It is accepted that the anterior cruciate ligament (ACL) is the primary restraint to tibial anterior translation. Rupture of ACL leads to altered knee kinematics and instability of the knee. The ACL reconstruction is usually necessary for these patients. However, the optimized tissue graft for use in ACL reconstruction is still the subject of controversy. In the past two decades, ACL reconstructions have been widely performed on patients using the bone patellar tendon bone (BPTB) and hamstring grafts with the arthroscopic technique. Moreover, the BPTB autograft has been accepted as the gold standard for ACL reconstruction because of its high success rates using osseous fixation mode. However, BPTB autograft harvest for ACL reconstruction may lead to donor site morbidities, such as patellar fracture, rupture of the patellar tendon, anterior knee pain, and knee extensor strength deficits, which leads to delayed recovery after ACL reconstruction [1]. In order to avoid the obstacles of autograft harvest, artificial ligament is introduced and become an alternative gradually to treat the ACL dysfunction. The synthetic material for ligament reconstruction was initially used in the 1980s. Unfortunately, the high failure rates and poor results were consentaneously reported by many studies [2, 3], which were mainly attributed to the

2 820 Eur J Orthop Surg Traumatol (2013) 23: Table 1 Details of the patients and the preoperative knee function scores BPTB group (n = 30) LARS group (n = 32) Male/female 19/11 25/7 Mean (±SD) age (years) ± ± Mean (±SD) time to operation (months) ± ± 6.99 Lysholm score (mean ± SD) ± ± Tegner score (mean ± SD) 3.30 ± ± 0.98 IKDC score A = normal 0 0 B = nearly normal 0 0 C = abnormal D = severely abnormal 7 10 artificial ligament rupture and severe reactive synovitis of the knee caused by wear particles. Therefore, the synthetic material for ACL reconstruction was recently replaced by the ligament advanced reinforcement system (LARS) artificial ligament (Surgical Implants and Devices, Arc-sur- Tille, France), and some satisfactory results have been obtained [4, 5]. However, the different effects of BPTB and LARS were not studied in detail yet in ACL reconstruction with midterm or long-term follow-up. Therefore, we compare here the midterm outcome of ACL reconstruction using BPTB autografts and LARS ligaments, respectively, with a minimum of 4-year follow-up. Our institutional review board approved this study. Materials and methods Between July 2004 and March 2006, 62 patients who underwent ACL reconstruction with the arthroscopic technique for isolated ACL rupture were included in this retrospective study. The diagnosis of ACL rupture was proved by history, clinical examination, and magnetic resonance imaging. Patients who had ACL rupture with meniscal and/or cartilaginous injury were also included. The patients who had a combined ligament injury, previous knee surgery history, contralateral knee ligament injury, osteoarthritis, and infection were excluded. The ACL reconstructions using BPTB autografts were performed in 30 patients, and the ACL reconstructions using LARS ligaments were performed in 32 patients. In the BPTB group, there were ten cartilaginous injuries, eleven medial meniscal tears, and six lateral meniscal tears. In the LARS group, there were eight cartilaginous injuries, thirteen medial meniscal tears, and four lateral meniscal tears. There were no significant differences between the two groups in terms of gender, age, time from injury to operation, Lysholm score, Tegner score, and IKDC score preoperatively (p [ 0.05) (Table 1). All patients were carefully informed about the disease detail and the potential risk and benefit of ACL reconstruction using BPTB autograft or LARS artificial ligament. According to the decisions of the patients, ACL reconstructions with BPTB autografts or LARS artificial ligaments were performed. All patients gave informed consent for this study. Surgical technique All surgeries were performed with the arthroscopic technique by the senior surgeon. After adequate anesthesia, the standard anterolateral and anteromedial approaches were taken. The joints were inspected under a 30 arthroscope. Anterior cruciate ligament rupture was confirmed, and any additional pathology of meniscal or cartilaginous injury was identified visually. Firstly, the meniscal injuries were treated by partial menisectomy and the cartilaginous injuries were treated by debridement. If the notch osteophytes or a narrow notch was found, the notchplasty must be performed. In the LARS group, ACL reconstructions were performed according to the isometric reconstruction principle [6]. ACL stumps were routinely preserved as much as possible. The diameters of the tibial and femoral tunnel made by the drill bit were 7.5 mm in all patients. The LARS drill guide passed through an anteromedial approach into the joint for drilling of the tibial tunnel. The intraarticular point of the tibial tunnel was located at the center of the ACL stump in the tibial insertion. The intraarticular point of the femoral tunnel was located at approximately 10:30 11:00 location in the right knee (or 1:00 1:30 in the left knee). After the Kirschner wire was drilled through the femur, the femoral tunnel was made by the drill bit from the anterolateral thigh into the knee joint along the Kirschner wire. Then, a wire loop was passed through the tibial tunnel, the joint, the femoral tunnel, and the lateral thigh sequentially. The LARS artificial ligament was passed in the loop and was pulled through the joint. The both ends of the artificial ligament filled into osseous tunnels with the longitudinal free fibers of the graft entering joint (Fig. 1).

3 Eur J Orthop Surg Traumatol (2013) 23: Noncompetitive sports were allowed after the second month and unrestricted sports were allowed after the sixth month postoperatively. In the BPTB group, quadriceps contraction was encouraged from the first day after surgery. Knee flexion exercises with a range of 0 to 90 were performed within the first 6 weeks. Flexion over 90 was allowed after the sixth week. Partial weight bearing with a hinged brace was introduced after the first week. Full weight bearing was allowed after the tenth week. Activities of daily living were permitted after the fourth month, and the unrestricted sports could be undertaken after the twelfth month postoperatively. Evaluation Fig. 1 The image showed that the portion of the longitudinal free fibers of a LARS ligament was located into a knee joint Both ends of artificial ligament were fixed by the titanium interference fit screws with blunt thread edges, the diameter of which was 8 mm on the femoral side and 9 mm on the tibial side. After the femoral end of the graft was fixed, the tibial end of the graft was pulled and the knee was cycled through full flexion to extension 20 times for graft pretensioning and settling. The knee was then placed at about 30 flexion and the tibial end of the graft was fixed with the screw. In the BPTB group, the BPTB autografts including the middle one-third of the patellar tendon were harvested and trimmed. Both the femoral and tibial tunnels were placed at the same locations as in the LARS group. And the diameters of both tunnels made by the drill bit were based on the diameters of proximal and distal bone blocks of the BPTB autografts. After the autograft was passed through the osseous tunnels, the bone blocks were fixed in the osseous tunnels by the same way as in the LARS group. Rehabilitation The postoperative rehabilitations were carried out according to different schedules in the two groups. In the LARS group, quadriceps contraction was initiated from the first day after surgery. Knee flexion from 0 to 90 was achieved within the first week and increased gradually to 120 within the second week. Patients walked with crutch from the third day and started full weight bearing at the fourth week postoperatively. Activities of daily living were permitted from 4 weeks to 2 months postoperatively. All patients were followed up for months with a mean of 50 months. All patients were evaluated using the Lysholm knee scoring scale [7], Tegner score [7], International Knee Documentation Committee (IKDC) scoring system [8], and KT-1000 arthrometer test. Statistical analysis of the data was performed using SPSS 10.0 software. Continuous variables were analyzed by the unpaired Student s t-test, the nominal data were analyzed by the chisquare test, and Categorical variables were analyzed by the Wilcoxon signed rank test, respectively. A difference was considered to be significant if the P value was less than Results The Lysholm scores, Tegner scores, and The IKDC scores at the latest follow-up were shown in the Table 2. The mean Lysholm score was ± 9.03 in the BPTB group and ± 6.75 in the LARS group (p [ 0.5). The mean Tegner score was 5.83 ± 1.18 in the BPTB group and 6.16 ± 1.17 in the LARS group (p [ 0.1). With regard to IKDC scores, twenty-six patients (86.7 %) were graded as normal or nearly normal and four patients were graded as abnormal in the BPTB group, and twenty-eight patients (87.5 %) were graded as normal or nearly normal and four patients were graded as abnormal in the LARS group (p [ 0.1). There were no significant differences between the two groups with respect to the three types of scores. Knee stability was measured by KT-1000 arthrometer (30 flexion and 134 N) at the latest follow-up. As shown in Table 2, the mean side-to-side difference in anterior translation was 2.62 ± 2.12 mm in the BPTB group and 2.29 ± 2.03 mm in the LARS group (p [ 0.5). The sideto-side difference was \3 mm in 21 patients (70.0 %) in the BPTB group and 24 patients (75.0 %) in the LARS group, 3 5 mm in 7 patients in the BPTB group and 5 patients in the LARS group, and more than 5 mm in 2

4 822 Eur J Orthop Surg Traumatol (2013) 23: Table 2 Scores of the knee function and stability examination postoperatively BPTB group (n = 30) LARS group (n = 32) P value Lysholm score (mean ± SD) ± ± 6.75 [0.5 Tegner score (mean ± SD) 5.83 ± ± 1.17 [0.5 IKDC score [0.5 A = normal B = nearly normal 12 9 C = abnormal 4 4 D = severely abnormal 0 0 KT-1000 (side-to-side difference) [0.5 \3 mm mm 7 5 [5 mm 2 3 Mean (±SD) of difference (mm) 2.62 ± ± 2.03 [0.5 patients in the BPTB group and 3 patients in the LARS group (p [ 0.1). The stability results showed that there was no significant difference between the two groups. In both groups, there was no obvious synovitis of the knees at follow-up. There were no superficial or deep infections in all patients, and wound healing occurred without complications postoperatively. Discussion In this study, we compared the clinical outcomes of ACL reconstruction using BPTB autograft versus LARS artificial ligament with a midterm follow-up. The results show that there are no significant differences between the BPTB autograft and LARS artificial ligament in terms of the knee function through examination of Lysholm scores, Tegner scores and IKDC scores, and the postoperative anterior laxity. It demonstrates similarly good clinical outcomes are obtained in both groups. In our study, good clinical result is obtained in the BPTB autograft group. A study [9] of biomechanical analysis of grafts has shown that the central portion of the BPTB is 168 % of the strength of the ACL, which is the strongest with respect to the semitendinosus and gracilis tendon (70 and 49 % of the strength of the ACL, respectively). The BPTB also has larger stiffness than the semitendinosus and gracilis tendons and fascia lata. In addition, both end segments of the BPTB graft are bone blocks that are pulled into the femoral and tibial osseous tunnels, respectively. The bone bone interface is better healed than the bone ligament interface [10]. Therefore, the BPTB is regarded as the excellent graft for ACL reconstruction. A study [11] has reviewed the results of 97 patients with arthroscopically assisted ACL reconstructions using BPTB autografts at the follow-up of 5 9 years postoperatively, which shows reliable stability, excellent functional testing results, and high level of patient satisfaction. However, the donor site morbidities, especially anterior knee pain, may occur after the ACL reconstruction using BPTB autografts [1]. In our study, patella fractures do not occur, but anterior knee pain occurs in two cases after the surgery and it lasts for 18 months. ACL reconstruction using BPTB allografts can eliminate these obstacles. But the allografts have some disadvantages, such as the risk of disease transmission and delayed incorporation. In order to avoid the obstacles of autograft harvest, ACL reconstruction using artificial ligaments is another alternative treatment. Recently, the new generation of the artificial ligament named LARS has been recommended for ACL reconstruction. It overcomes the shortcoming of previous artificial ligament to some degree. It is made of polyethylene terephthalate polyester. Its elasticity is very low and strength is sufficient for ACL reconstruction, 2,500 or 3,600 N corresponding to 60 gauge or 80 gauge. The intraarticular longitudinal fibers of the LARS ligament can induce the ingrowth of autologous collagen tissue [12]. Dericks [6] has reported that 220 patients undergo ACL reconstruction using LARS ligament, and the good results are obtained after a mean follow-up of 2.5 years. A multicenter study of ACL reconstruction using LARS artificial ligament with 3- to 5-year follow-up has shown a comparable result in comparison with autograft and allograft ACL reconstruction [5]. Lavoie et al. [4] have followed 47 patients who had undergone ACL reconstruction using LARS ligament with 8 45 months postoperatively and have found no synovitis or implant failure. Moreover, Nau et al. [13] have carried out a randomized clinical trial by comparing ACL reconstruction using LARS artificial ligaments in 26 patients and BPTB autografts in 27 patients. The results show the Knee and Osteoarthritis Outcome Score (KOOS) and instrument-tested laxity are better in the

5 Eur J Orthop Surg Traumatol (2013) 23: LARS group than BPTB group at 12-month follow-up; however, there is no difference with regard to IKDC score, Tegner score, the KOOS, and instrumented laxity testing at 24-month follow-up between the two groups without reactive synovitis. That study also suggests that the LARS ligament seems to be a satisfactory treatment, especially for the demand of early return to high levels of activity. We also obtain similar and good clinical result for two types of treatments in our study with a midterm follow-up. Although no significant difference has been observed between the BPTB autograft and LARS artificial ligament in terms of the Lysholm scores, Tegner scores, IKDC scores, and the postoperative anterior laxity, these data show a better tendency in the LARS group compared with the BPTB group. In conclusion, our study demonstrates similarly good clinical results after ACL reconstruction using LARS ligaments or BPTB autografts at midterm follow-up. In addition to BPTB autografts, the LARS ligament may be a satisfactory treatment option for ACL rupture. Acknowledgments This work was supported by the clinical foundation of medical association of Zhejiang province (2011ZYC-A024) and Science and Technology Project of Wenzhou City (Y ). Conflict of interest of interest. References The authors declare that they have no conflict 1. Busam ML, Provencher MT, Bach BR (2008) Complications of anterior cruciate ligament reconstruction with bone-patellar tendon-bone constructs. Care and prevention. Am J Sports Med 36: Klein W, Jensen KU (1992) Synovitis and artificial ligaments. Arthroscopy 8: Paulos LE, Rosenberg TD, Grewe SR, Tearse DS, Beck CL (1992) The GORE-TEX anterior cruciate ligament prosthesis. A long-term followup. Am J Sports Med 20: Lavoie P, Fletcher J, Duval N (2000) Patient satisfaction needs as related to knee stability and objective findings after ACL reconstruction using the LARS artificial ligament. Knee 7: Gao K, Chen S, Wang L, Zhang W, Kang Y, Dong Q, Zhou H, Li L (2010) Anterior cruciate ligament reconstruction with lars artificial ligament: a multicenter study with 3 to 5-year follow-up. Arthroscopy 26: Dericks G (1995) Ligament advanced reinforcement system anterior cruciate ligament reconstruction. Oper Tech Sports Med 3: Tegner Y, Lysholm J (1985) Rating systems in the evaluation of knee ligament injuries. Clin Orthop Relat Res 198: Hefti E, Müller W, Jakob RP, Stäubli HU (1993) Evaluation of knee ligament injuries with the IKDC form. Knee Surg Sports Traumatol Arthrosc 1: Noyes FR, Butler DL, Grood ES, Zernicke RF, Hefzy MS (1984) Biomechanical analysis of human ligament grafts used in kneeligament repairs and reconstructions. J Bone Joint Surg Am 66: Park MJ, Lee MC, Seong SC (2001) A comparative study of the healing of tendon autograft and tendon-bone autograft using patellar tendon in rabbits. J Int Orthop 25: Bach BR, Tradonsky S, Bojchuk J, Levy ME, Bush-Joseph CA, Khan NH (1998) Arthroscopically assisted anterior cruciate ligament reconstruction using patellar tendon autograft. Five to nine-year follow-up evaluation. Am J Sports Med 26: Yu S, Dong Q, Wang Y, Zuo Z, Li D (2008) Histological characteristics and ultrastructure of polyethylene terephthalate LARS ligament following the reconstruction of anterior cruciate ligament in rabbits. J Clin Rehabil Tissue Eng Res 12: Nau T, Lavoie P, Duval N (2002) A new generation of artificial ligaments in reconstruction of the anterior cruciate ligament. Two-year follow-up of a randomised trial. J Bone Joint Surg Br 84: