Knee Surgery, Sports Traumatology, Arthroscopy https://doi.org/10.1007/s00167-018-4940-4
KNEE
LARS synthetic ligaments for the acute management of 111 acute knee dislocations: effective surgical treatment for most ligaments Pierre Ranger1,2,3 · Andréa Senay1,3 · Geneviève Rochette Gratton3 · Marc Lacelle2 · Josée Delisle1,2 Received: 23 October 2017 / Accepted: 4 April 2018 © European Society of Sports Traumatology, Knee Surgery, Arthroscopy (ESSKA) 2018
Abstract Purpose The purpose of this study was to describe the longitudinal outcomes of acute repair and augmentation for the reconstruction of dislocated knees, using LARS synthetic ligaments. Methods Patients with a knee dislocation surgically treated using LARS synthetic ligament augmentation, with a minimum follow-up of 24 months, were enrolled between 1996 and 2014. Range of motion, Lachman, pivot shift, posterior drawer, step off sign, valgus, varus, KT-1000 arthrometer, Telos technique, IKDC, Lysholm, Tegner, and Meyers scores were obtained every 2 years up to 10 years. Results Median age was 32.1 years (IQR 23.2–43.3) at time of surgery. Median time from trauma to surgery was 9 days and mean follow-up time was 6.6 years. Median questionnaire scores were: Lysholm 79.5 (IQR 65.0–89.0), Tegner 4.0 (IQR 3.7–6.0), Meyers 3.0 (IQR 3.0–4.0), and mean IKDC was 63.8 (SD 18.9). Median flexion and extension of the injured knee was 124° (IQR 115–129.5) and 0° (IQR − 5 to 0), respectively. Median KT-1000 differential was 0.7 mm (IQR 0.1–3.1) for ACL and 0.9 mm (IQR 0.2–1.4) for PCL. Mean differential for Telos was 2.5 mm (SD 5.8) for ACL, 4 mm (IQR 2–6.3) for PCL 30°, and 8.2 mm (SD 4.4) for PCL 90° (consistent with PCL laxity). More than 90% of patients had good anterior articular stability and > 60% of patients had good posterior articular stability. Conclusions Acute repair and augmentation of knee dislocations with LARS synthetic ligaments resulted in satisfactory outcomes for the ACL and collateral structures. Telos stress radiography showed PCL laxity in more than half of cases despite low laxity results with KT-1000. The perception of patients about knee function was sustained in time. Level of evidence IV. Keywords Knee dislocation · Surgical management · Augmentation · Repair · Synthetic ligament · LARS
Introduction
Electronic supplementary material The online version of this article (https://doi.org/10.1007/s00167-018-4940-4) contains supplementary material, which is available to authorized users. * Josée Delisle
[email protected] 1
Orthopaedic Research Center, Hôpital du Sacré-Coeur de Montréal, 5400, boulevard Gouin Ouest, Montreal, QC H4J 1C5, Canada
2
Hôpital Jean-Talon, 1385 rue Jean‑Talon est, Montreal H2E 1S6, Canada
3
Université de Montréal, 2900 bl. Edouard‑Montpetit, Montreal H3T 1J4, Canada
Knee dislocations are an uncommon orthopaedic injury, involving the rupture of two or more major ligaments and causing the displacement of the tibia relative to the femur [5, 6, 14]. Treatment methods and management of these injuries are subject to debate. Conservative treatment, with immobilization and physiotherapy, is advocated by some as it would allow flexion and stabilize the knee [22]. However, surgical management has demonstrated clear advantages in terms of return to previous activities and functional capacity, compared to the conservative approach [22, 28, 33]. Acute management of this condition, surgery within 21 days following trauma [17], was found to have a superior outcome compared to chronic management, surgery more than 21 days after trauma [17, 22, 28, 33, 38], although the risk of arthrofibrosis is greater with acute management [8].
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Knee Surgery, Sports Traumatology, Arthroscopy
Several studies report good results with reconstruction and repair using allografts and autografts for the early surgical management, but very few have studied repair and augmentation of dislocated knees using synthetic grafts [15, 19, 22]. The first generation of synthetic ligaments was labelled a poor choice for surgical treatment because of failure resulting in instability and synovitis [26]. More recently, the ligament advanced reinforcement system (LARS) (Surgical Implant and Devices, Arc-sur-Tille, France) achieved good outcomes in single-ligament repair and augmentation surgeries [3, 10, 23, 24, 35]. It consists of intertwined fibers made of terephthalic polyethylene woven together to help decrease the risk of rupture. The current study aimed to determine if the early operative management of acute knee dislocations using LARS was an effective treatment choice. It was hypothesized that clinical outcomes would show good knee function, a return to previous work, and activities for most patients, as well as few postoperative complications. To the best of our knowledge, this was the first time that the LARS synthetic ligament effectiveness was studied in a large group of cases with complete knee dislocations (minimum ACL + PCL) over a long postoperative period.
Materials and methods This was an observational case series of 111 knee dislocations with ruptured ligaments, treated with LARS augmentation, between 1996 and 2014. Files of eligible patients were retrospectively reviewed and patients willing to participate were followed over a 10-year period at 24-month intervals. Figure 1 describes the recruitment process.
Study population Inclusion criteria were (1) subjects 18 years or older, (2) who sustained an acute knee dislocation (21 days or less) involving the ACL and the PCL with or without another structure, and (3) referred for treatment of the injured ligaments with LARS synthetic ligaments. Patients were excluded if (1) they were less than 18 years old, (2) presented proximal tibia or distal femur physes, (3) chronic dislocation, (4) infection of surgery site, (5) were unable to undergo surgery, or (6) had bilateral knee dislocations. Collected data included demographic information, type of trauma, body mass index (BMI), type of knee dislocation, associated injuries, surgical adverse events, and complications. Acute knee dislocation was diagnosed following magnetic resonance imaging (MRI) results. The type of dislocation was classified according to Schenck’s criteria; ACL or PCL (KD-I), ACL/PCL only (KDII), ACL/PCL and PMC or PLC (KDIII-M or L), and ACL/PCL/PMC/PLC (KDIV) [14, 33]. However, in this study, for the tibia to be considered displaced relative to the femur, both cruciate ligaments needed to be ruptured, thus excluding KD-I as knee dislocations. Mechanisms of injury were classified as either high-velocity (motor vehicle accident) or low-velocity (sports injury or less) traumas. Tables 1, 2 show baseline patient characteristics and demographic data. The majority of participants were male, median time from trauma to surgery was under 9 days, mean time from surgery to follow-up was 6.6 years and more than 65% of patients sustained their injury through a high-velocity trauma. All the participants had a tear in the central pivot, which was associated with another rupture in more than 90% of cases (KD-III and KD-IV). More than two major structures were affected in most participants and over 85% had an associated injury, most frequently to the meniscus.
Surgical technique
209 acute KD
Ligament repair (realignment) followed by reconstruction (internal brace) was performed within 3 weeks, according
144 reconstructions performed > 24 months ago (68.9%) Bilateral reconstructions (n = 14) Patient revised to TKA (n = 3)
127 patients met inclusion criteria (88.2%)
Refusal (n = 8) Loss to follow-up (n = 8)
111 patients with at least one follow-up visit (87.4%)
Table 1 Patient demographics Number of cases Male gender Age (years)a BMI (kg/m2) BMI < 30 kg/m2 BMI ≥ 30 kg/m2 Results presented either as n (%) or median (IQR)
Fig. 1 Study flow diagram. KD knee dislocation, TKA total knee arthroplasty
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BMI body mass index, IQR interquartile range
a
At the time of surgery
111 86 (77.5) 32.1 (23.2–43.3) 26.5 (24.1–30.5) 80 (72.1) 31 (27.9)
Knee Surgery, Sports Traumatology, Arthroscopy Table 2 Patient characteristics Characteristics Time from trauma to surgery (days) ≤ 14 > 14 and ≤ 21 Time from surgery to follow-up (years)a Mechanism of injury High velocity Low velocity Knee dislocation classification KD-II KD-IIIL KD-IIIM KD-IV Associated injuries Meniscus Peroneal nerve Vascular > 1 associated injury None Single-bundle PCL repair Double-bundle PCL repair Polytrauma
9.0 (6.0–14.0) 84 (75.7) 27 (24.3) 6.7 (1.8–16.9) 74 (66.7) 37 (33.3) 5 (4.5) 42 (37.8) 38 (34.2) 26 (23.4) 92 (83.6) 21 (19.1) 19 (17.3) 35 (31.8) 14 (12.7) 24 (21.6) 87 (78.4) 31 (27.9)
Results presented either as n (%) or median (IQR) KD knee dislocation, IQR interquartile range, PCL posterior cruciate ligament a
Mean (minimum, maximum)
to the open reduction and internal fixation (ORIF) principle. During surgery, the patient was placed in the supine position, under general or regional anaesthesia, and re-examined to confirm the type of instability and plan the reconstruction. A tourniquet and lateral and distal supports were positioned to hold the knee in 90° of flexion, while also allowing full range of motion and access to the posterolateral and posteromedial corners. A midline incision and a medial parapatellar arthrotomy were performed. Meniscal tears were sutured. Remaining stumps of the central pivot were preserved and sutured with heavy non-absorbable suture. For the PCL, our goal was to isolate one bundle (before 2001) or the two bundles (after 2001). Tunnels were made with the LARS guiding system, using a double-bundle technique for the PCL (anterolateral and posteromedial bundle) and a standard single-bundle for the ACL, at 2 o’clock and 10 o’clock for left and right knees, respectively. An anatomical reconstruction of the extra-articular ligaments was then performed, and mid-substance tears were sutured and reinforced with an internal brace system (LARS ligament). Avulsions were fixed with anchors and peel-off was re-attached with staples. The posterolateral corner was reconstructed using the posterolateral approach.
The peroneal nerve was identified and retracted. The popliteus, the LCL, and the popliteofibular ligaments were identified and stitched with heavy non-absorbable Fiberwire 2.0 sutures. Femoral and tibial tunnels were positioned according to the LaPrade1 technique if there was mid-substance rupture, and augmented with internal brace [27, 34]. Repair of the posteromedial corner followed the same principle of anatomical reconstruction as the posterolateral corner: peel-off fixed with staples, mid-substances sutured and augmented with internal brace (LARS ligament), and avulsion fixed with anchors. For the final fixation, synthetic ligaments were inserted through each tunnel. The final reconstruction with augmentation showed the internal braces covered with the original ligaments. Metallic screw fixation was then completed as follows: PCL AM bundle tensioned at 90° of flexion with an anterior force to restore the normal step off and PCL PM in 30°; PLC at 30° of flexion and foot in neutral rotation as well as LCL; ACL was tensioned at 30° as well as the MCL [36].
Rehabilitation The knee was protected with a hinged brace for 12 weeks, to prevent stress to the peripheral ligaments. Indomethacin (25 mg three times daily for 3 weeks) was prescribed to prevent heterotopic ossification. Physiotherapy began on the first postop day. Toe-touch was encouraged and the goal, 6 weeks postoperatively, was 0° of extension and 90° of flexion. When the patient reached 115° of flexion, stationary bicycle was allowed with low resistance. At 6 weeks, most patients had enough strength and control to start weightbearing exercises, to leave crutches progressively, and start a program of closed-chain exercises to protect peripheral structures. At 3 months, proprioception exercises could begin. Return to sports activities was possible with a functional brace at a minimum of 9 months postoperatively. The final objective was to take off the brace for daily activities 1 year after surgery.
Clinical evaluation Participants were seen every 24 months by a trained interviewer (research assistant with a Master’s degree in clinical research and experience with patient interviews for research purposes) to answer questionnaires and by a physiotherapist for clinical assessments, up to 10 years postop. Functional assessment was performed using the following clinical tests: varus/valgus (0°, 30°), Lachman, pivot shift, posterior drawer, step off sign, KT-1000 arthrometer 134N (15 pounds) (Medmetric, San Diego, California), and Telos stress radiography with a pressure of 15 kPa (ACL 30°, PCL 30°, 90°) (Telos, Weterstadt, Germany). The International Knee Documentation Committee (IKDC) subjective knee
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form was used to measure daily living and sports activity levels, symptoms (pain, swelling, stiffness, etc.), and knee function of subjects [4]. The Lysholm knee scoring scale evaluated knee instability [4], while the Tegner activity score measured daily work and sports activities with a score ranging from 0 to 10 [4]. Finally, the Meyers score, commonly used in knee dislocation studies, measured symptoms and instability on a scale of 1–4 [29].
Statistical analysis Outcomes were described using median and interquartile range, since most of the data were not normally distributed. Several subgroup comparisons were performed using nonparametric Mann–Whitney tests; type of injury (KD-II–IV), high vs low velocity, single vs double bundles for PCL and BMI < 30 vs ≥ 30 kg/m2. An intra-patient analysis was conducted, comparing results from the first and last followup for patients seen more than once, and using Wilcoxon signed-rank tests for paired outcomes. Statistical analysis was performed with SPSS Statistics version 19.0 (IBM Corp., Armonyk, NY, USA, 2010). A p value of ≤ 0.05 was considered to be statistically significant.
Knee Surgery, Sports Traumatology, Arthroscopy Table 3 Functional and clinical assessment outcomes at last followup N Questionnaires IKDC Lysholm Tegner Meyers Range of motion (°) Flexion Flexion diff. Extension Extension diff. Laxity measurement (mm)b KT-1000 ACL KT-1000 PCL Telos ACL
Median (IQR)
105 102 98 98
63.8 (18.9)a 79.5 (65.0–89.0) 4.0 (3.7–6.0) 3.0 (3.0–4.0)
109 109 109 109
124.0 (115.0–129.5) 10.0 (5.0–15.0) 0.0 (− 5.0–0.0) 4.0 (0.0–5.0)
111 111 101
3.3 (1.2–5.7) 1.8 (0.8–2.2) 6.5 (4.7)a
ACL anterior cruciate ligament, diff. side-to-side difference between injured and other knee, IKDC International Knee Documentation Committee, IQR interquartile range, PCL posterior cruciate ligament a
Mean (standard deviation)
b
Side-to-side difference for laxity measures with KT-1000 and Telos are presented in Fig. 2
Results
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8.2
8 Mean differenal (mm)
Table 3 shows functional assessment results for questionnaires, range of motion and laxity of the injured knee at last follow-up visit (mean of 6.6 years after surgery). The mean IKDC score corresponded to a fair level of daily sports activities with some symptoms and moderate functional limitation of the knee, while the Lysholm median score indicated fair knee stability. The Tegner median score concurred with return to work for moderate-to-heavy labor (e.g. construction workers). The median Meyers score corresponded to a good return to work with little knee instability. The side-to-side difference for laxity measurement methods is presented in Fig. 2. All the results for differential PCL stability were statistically significantly different (KT-1000, Telos 30°, Telos 90°, p < 0.001). ACL and PCL stability were worse according to Telos, compared with the arthrometer. Figure 3 shows the results for the physical exam functional tests. Between 26 and 31% of patients had a varus/ valgus grade 2 or 3 when measured at 30°. Lachman and pivot shift showed that a majority of patients had a grade 0 or 1, whilst posterior drawer and step off sign measurements found 36–39% of patients with grade 2 or 3. Regarding subgroup comparisons, patients with a BMI < 30 kg/m2 had Lysholm and Tegner scores as well as knee flexion significantly higher than patients with a BMI ≥ 30 kg/m2. However, patients with a BMI < 30 kg/ m2 showed worse anterior translation of the injured ACL
** 9 7
**
6 5
*
4
2.5
3 2 1 0
4
0.9
0.7 KT-1000 ACL
Telos ACL
KT-1000 PCL Telos PCL 30° Telos PCL 90° Laxity tests
Fig. 2 Median side-to-side differences for KT-1000 arthrometer and Telos stress radiography to measure laxity for the anterior cruciate ligament (ACL) and the posterior cruciate ligament (PCL). *p > 0.05 (statistically non-significant), **p < 0.001 (statistically significant)
measured with the KT-1000 and side-to-side difference for the PCL measured with the 90° Telos. KD-IV patients had significantly worse scores on the IKDC and Tegner tests, when compared to KD-II and KD-III cases. They also had a higher side-to-side difference for the ACL on the KT-1000 and knee flexion. When high-velocity traumas were compared to low-velocity traumas, there was a significant difference for the translation of the injured ACL and PCL measured with the KT-1000; low-velocity traumas had worse laxity results than high-velocity traumas.
Knee Surgery, Sports Traumatology, Arthroscopy
Proporon of paents
80% 70% 60%
72.5% 67.0% 61.1%
50%
40% 30%
50.5%
48.3%
48.1%
45.9% 44.0%
39.1%
36.1% 30.6%
27.5%
20% 6.5% 1.9%
0%
Lachman
Pivot Shi
32.1%
30.3%
Grade 3 1.1%
0.9%
Posterior drawer
Grade 1 Grade 2
11.5%
8.3% 1.8%
31.2% 26.6%
19.3%
14.8%
10%
Grade 0
41.3%
Step off sign
0.9%
0.0%0.0%
Valgus 0°
Valgus 30°
0.9%0.0%
Varus 0°
0.0%
Varus 30°
Fig. 3 Proportion of patients with grade 0, 1, 2, or 3 according to varus/valgus stress, step off sign, posterior drawer, pivot shift, and Lachman tests Table 4 Intra-patient analysis comparing the first vs last follow-up in 54 knee dislocation patients that had two or more follow-up assessments First FU vs last FU Median (IQR)
Age (years) Time to FU (years) Lysholm Tegner Meyers IKDCa ROM flexion ROM extension Telos ACL diff.a Telos PCL 30° diff. Telos PCL 90° diff.
p value
First
Last
39.0 (26.7–47.5) 3.7 (2.9–5.0) 84.0 (72.0–94.0) 5.0 (4.0–6.0) 3.0 (3.0–4.0) 72.6 (17.6) 120.0 (113.0– 128.0) − 2.0 (− 4.0 to 0.0) 1.8 (5.2) 4.0 (2.2–7.0)
45.0 (32.2–53.2) < 0.001 8.4 (6.7–11.1) < 0.001 85.0 (71.5–92.0) 0.513 4.0 (4.0–7.0) 0.769 3.0 (3.0–4.0) 0.818 68.3 (20.3) 0.122 124.0 (115.0– 0.038 130.0) − 5.0 (− 5.0 to 0.0) 0.018 1.7 (5.5) 0.837 4.5 (2.0–6.7) 0.342
8.0 (5.5–10.0)
9.5 (5.0–11.0)
0.040
First and last follow-up compared using Wilcoxon signed-rank tests for paired samples, except when stated otherwise Range of motion measured in degrees, laxity measured in millimeters Statistically significant values are in bold ACL anterior cruciate ligament, diff. side-to-side difference between injured and contralateral knee, FU follow-up, IKDC International Knee Documentation Committee, IQR interquartile range, ROM range of motion, PCL posterior cruciate ligament
Table 5 Complications following repair and reconstruction with augmentation using LARS synthetic ligaments of dislocated knees Type of complication
N (%)
Open arthrolysis Heterotopic ossification Compartment syndrome Infection Revisiona LARS rupture
18 (16.2) 24 (21.6) 4 (3.6%) 1 (0.9%) 6 (5.4%) 2 (1.8%)
Recurrent ACL tears were repaired using autograft [bone tendon bone (patellar tendon)]
a
Reasons for revision: screw adjustments (screw consolidation, metal sensitivity), ACL tear following a second knee injury
visit time (3.7 years) and the mean last follow-up visit time (8.4 years). Range of motion was significantly improved in terms of flexion and extension at last follow-up visit. However, a millimeter was added to the side-to-side difference between injured and contralateral knee for the PCL measured at 90°, and this was statistically significant. Other clinical parameters and questionnaire scores remained stable over time. Moderate and severe osteoarthritis was observed in 16 cases (14.4%) at a mean time of 5.8 ± 4.1 years after repair. Osteoarthritis was diagnosed based on a radiological assessment and the Kellgren–Lawrence grading system [18].
a
Mean (standard deviation), Student’s t test for paired samples
Single-bundle patients had a better knee flexion than double-bundle patients. Detailed statistical results of subgroup comparisons can be found in Supplementary materials (Table S1). The intra-patient analysis, comparing the first and last follow-up visits for 54 patients, is shown in Table 4. There was approximately 5 years between the median first follow-up
Complications Complications are shown in Table 5. One patient had a ruptured ACL graft 3 years after repair and augmentation and underwent ACL revision with patellar tendon autograft. Another had a graft for ACL and left medial meniscus rupture as well as an anterior ligament reconstruction with patellar tendon autograft, 6 years after surgery.
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Discussion The results of this study suggest that the use of LARS synthetic ligaments for the augmentation of repair and reconstruction of knee dislocations may be an effective surgical treatment choice for the restoration of most knee ligaments. This study aimed to describe longitudinal clinical- and patient-reported outcomes in a group of patients undergoing acute management for a dislocated knee, and repaired and reconstructed with augmentation using LARS synthetic ligaments. After a mean follow-up time of 6 years, the most significant results were; (1) stress radiography (using Telos) showed important PCL laxity, (2) there was residual laxity of collateral structures in 25–30% of cases in patients who had no augmentation surgery on their collateral ligament, (3) ACL repair was optimal. Patientreported outcomes regarding quality of life, return to previous activities, and knee function were good. To the best of our knowledge, papers on treatment options for multiligament knee injuries published over the last decade have sample sizes ranging from 8 to 85 patients. Reported follow-up periods varied between 1 and 13 years [1, 5, 7, 9, 13, 15, 20, 25, 30, 31]. The most recent studies on knee dislocation with LARS synthetic ligaments were four retrospective case series of 9–31 multiligament injuries or knee dislocations. The average follow-up time ranged between 2.5 and 10 years [11, 16, 19, 39]. One study evaluated posterior stability using stress radiographs, but only the PCL was reconstructed using LARS and some of the cases did not have a concomitant disruption of the PCL and the ACL [11]. Arthrometers, like the KT-1000, allow objective quantifiable measurements of anterior translation. However, stress radiography, like the Telos, is more accurate for the measurement of PCL insufficiency [32]. Nonetheless, an arthrometer is often used to measure PCL laxity in the literature. When comparing laxity differentials obtained by the KT-1000 and the Telos, major differences were recorded for the PCL (Fig. 2). The study of Gliatis et al. on KD reconstruction augmented with LARS reported a mean posterior displacement of 3.6 mm for the injured knee compared to a mean posterior displacement of the contralateral knee of 0.9 mm (mean differential of 2.7 mm) using the Telos stress device [11]. Telos stress radiography was also used in three retrospective case series of 13–68 knee dislocations, and acutely and chronically reconstructed, using autograft and allograft. Results were lower than this study (1.9–4.5 mm differential vs 8.2 mm) [9, 12, 13]. In similar acute and mixed chronic/acute reconstruction studies, posterior laxity measured with the KT-1000 varied from 1.9 to 2.6 mm (0.9 mm for the present study)
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Knee Surgery, Sports Traumatology, Arthroscopy
[9, 13, 15]. These major differences between results illustrate the importance of using valid radiological assessment techniques for the measurement of posterior stability after PCL knee reconstruction, contrary to what is found in most studies. The use of synthetic ligaments for augmented ACL reconstruction showed good results in this case series, with a mean side-to-side difference of 0.7 mm according to the KT-1000 arthrometer. In similar studies, KT-1000 measurements were mostly taken to measure anterior laxity and ranged from 0.1 to 2.9 mm [7, 9, 13, 15, 25]. In a study using synthetic ligaments, the average difference between the injured and contralateral knee, when measured anteriorly with the KT-1000, was 0.1 mm [16]. Regarding the repair of collateral ligaments, the present study’s results showed that primary repair of collateral structures, with 26–31% of patients presenting valgus and varus laxity (30°), might not yield optimal results compared to reconstruction. This is comparable to reported data, where 37–40% of MCL, LCL and PLC repairs failed, whereas only 6–9% of reconstructions failed [21, 37]. Therefore, the surgical technique was adjusted for the MCL and the augmentation technique was used, with much better results. Similar scores were reported in other reconstruction studies for the Lysholm scores (median of 79.5 in this study) ranging between 77 and 91 in the literature [1, 7, 9, 11, 15, 16, 19, 20, 25, 30, 31, 39]; the Tegner activity level (median of 4.0 in this study) ranging between 4 and 5.5 in the literature [1, 7, 9, 16, 20, 25, 30, 31, 39]; the IKDC score (mean of 63.8 in this study) ranging between 64 and 79.3 in the literature [7, 11, 19, 25, 30]; and the side-to-side difference in the loss of flexion and extension (median of 10° and 4°, respectively, in this study) ranging between 5°–15° and 1°–5°, respectively, in the literature [9, 15, 16, 20, 25, 31]. Results for ACL and PCL laxity for the operated knee were better in patients having suffered high-velocity trauma. The lead investigator of this study speculated that the more substantial injuries and soft-tissue ruptures could lead to extensive soft-tissue scarring after reduction and contribute to stability, helping maintain the repaired knee structures intact. Outcomes of the 24 patients initially operated using a single-bundle repair (until 2001) were also compared with those of the 87 patients who underwent a double-bundle repair, but no significant difference was found except for a higher knee flexion for single-bundle patients compared to double-bundle patients, which was still over 120° in both groups. These findings corroborate results from other studies on acute PCL reconstruction [2]. Patients with a BMI higher than 30 kg/m2 perceived themselves as having a weaker knee function compared to other patients. PCL laxity was only different with the 90° Telos, where patients with a BMI ≥ 30 kg/m2 had better outcomes.
Knee Surgery, Sports Traumatology, Arthroscopy
A review by Mascarenhas and McDonald showed that the LARS synthetic ligament offered many benefits for ACL reconstruction, such as promoting tissue growth through its porosity and its resemblance to the innate form of the ACL [26]. However, they reported difficulties when it came to eliminating residual laxity. Therefore, to determine the long-term effects of the LARS synthetic ligament on laxity, we compared the outcomes of the first and last follow-up visits in eligible participants (n = 54). Our results show the persistence of all patient-reported and most clinical outcomes, up to 8 years on average, after surgery. There was a mild improvement in knee flexion, and worse knee extension and side-to-side difference for posterior stability using the 90° Telos. This study has limitations. First, potential bias sources from analyses were not excluded such as single-bundle patients or the high number of comorbidities to the lower limb, which could impact the results. Nonetheless, subgroup analyses showed almost no difference when it came to the type of bundle technique, weight, or the number of days before surgery. In addition, the valgus and varus laxity assessment would have been more accurate with stress radiography. Furthermore, functional outcome questionnaire results could be underestimated, considering the effect of residual pain on perceived quality of life and of comorbidities on total limb function [40]. Indeed, 27.9% of the cohort was polytrauma cases. Due to various reasons such as unavailability, vacations, or relocation, some patients were not seen precisely every 2 years. Thus, the time from surgery to outcomes was variable, creating a heterogeneous group, which can lead to a great variability in data and results. However, the study design was meant to offset the number of patients who missed their 24-month appointments, and the intra-analysis showed that most outcomes are persistent over time. Finally, a comparative study with a control group would have had a higher level of evidence. Nevertheless, this work extends the clinical evidence on surgical management of knee dislocations and multiligament knee injuries. This is clinically relevant as similar studies were done on small groups of cases oftentimes including non-concomitant ACL and PCL tears. Moreover, posterior stability was assessed using stress radiographs instead of an arthrometer. Results show that LARS synthetic ligaments can be an effective surgical treatment for the augmentation of repair and reconstruction of the ACL and collateral structures, but not for the PCL in knee dislocation cases. It can also be considered as an alternative to the use of allograft when unavailable.
functional capacity, and knee function after surgery. This technique was most effective in ACL reconstructions, with no residual laxity of collateral structures in almost 70% of cases. It also resulted in important laxity of the PCL, consistent with PCL tears, in more than half of the cases according to Telos stress radiography for posterior translation. Thus, other reconstruction techniques might yield a better collateral and posterior stability. Future studies on the effect of PCL surgical reconstruction techniques on clinical outcomes, with or without associated injuries, should assess side-to-side stability using a validated radiological assessment such as stress radiography. Acknowledgements We would like to thank Dr. Fernando Rosa for his precious contribution to manuscript redaction, Mr. David Yin for his help with language form, and Dr. Alexandre Renaud for his help in the development of this project. Author contributions PR is the principle investigator of this study, thus contributing to all aspects of it; conception and design, protocol redaction, ethics approval, patient recruitment, data acquisition, interpretation of data, and drafting and revision of manuscript. AS contributed substantially to literature review, data collection by recruiting patients, organising follow-up visits, data entry, performing data analysis, and manuscript redaction. GRG has been in charge of database development, organization of clinics and patients’ follow-up for 2 years, and has contributed to manuscript redaction and revision. ML has contributed to conception of the study in terms of functional assessments, and has proceeded to all functional evaluations of patients during clinics over the study period and to the revision of the manuscript. JD, as the study coordinator, has contributed substantially to conception, design, literature review, protocol redaction, ethics approval, research team schedule, study planning, and manuscript revision. Funding Dr. Pierre Ranger reports grants from Johnson & Johnson, support as a consultant from Smith & Nephew, Corin, Bioventus, Sanofi Canada, and support for development of educational presentations by Horizon Pharma outside of the conducted work. Josée Delisle also reports support for personal fees from Amgen Canada and Eli Lilly outside of the conducted work.
Compliance with ethical standards Conflict of interest All authors declare that they have no conflict of interest. Ethical approval This study was approved by the Hôpital du SacréCoeur de Montréal ethic research committee in Montréal, Québec, Canada (IRB #2008-03-116; 2010 − 285). All procedures performed in this study were in accordance with the ethical standards of the hospital’s ethic research committee and with the 1964 Helsinki declaration and its later amendments or comparable ethical standards. Informed consent All subjects provided informed consent.
Conclusions The use of LARS synthetic ligaments for augmented reconstruction and repair of knee dislocations in a series of 111 cases resulted, overall, in good self-reported quality of life,
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