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No Difference in Functional Outcomes When Lateral Extra-Articular Tenodesis Is Added to Anterior Cruciate Ligament Reconstruction in Young Active Patients: The Stability Study

      Purpose

      To assess the functional outcomes of patients included in the Stability Study randomized controlled trial comparing anterior cruciate ligament reconstruction (ACLR) alone with ACLR with lateral extra-articular tenodesis (LET) at 6, 12, and 24 months postoperatively.

      Methods

      Six hundred eighteen patients undergoing ACLR, all under the age of 25 years either returning to contact pivoting sport or displaying signs of high-grade rotatory laxity or generalized ligamentous laxity, were randomly assigned to receive ACLR alone or ACLR plus LET. A total of 356 of these patients were randomized at centers participating in the functional assessments. Our primary outcome was Limb Symmetry Index, calculated using a series of 4-hop tests at 6, 12, and 24 months postoperatively. Secondary outcome measures included pain, patient-reported function, and isokinetic strength testing.

      Results

      We found no statistically significant difference in the proportion of patients either unwilling or unfit to complete the hop testing in the ACLR alone or ACLR with LET group at 6 months (40 vs 40 respectively; P = 1.00), 12 months (25 vs 27; P = .76), and 24 months (21 vs 23; P = .87). Of those who completed hop testing, there were no statistically significant differences between groups in Limb Symmetry Index at 6, 12, or 24 months. Self-reported function (Lower Extremity Functional Score) significantly favored the ACLR alone group at 3 (P = .01) and 6 months (P = .02) postoperative but was similar by 12 months postoperative. Pain scores (P4) also showed a statistically significant difference in favor of the ACL alone group, but this also resolved by 6 months. Quadriceps peak torque (P = .03) and average power (P = .01) were also significantly different in favor of the ACLR alone group at 6 months postoperative; however, these were similar between groups by 12 months postoperative (P = .11 and P = .32, respectively).

      Conclusions

      The addition of a LET to ACLR results in slightly increased pain, a mild reduction in quadriceps strength, and reduced subjective functional recovery up to 6 months postoperatively. However, these differences do not have any impact on objective function as measured by hop test limb symmetry index.

      Level of Evidence

      I, Randomized Controlled Trial.
      Anterior cruciate ligament (ACL) injuries are one of the most common knee injuries,
      • Brukner P.
      • Khan K.
      Clinical Sports Medicine.
      with anterior cruciate ligament reconstruction (ACLR) being the sixth most common procedure performed in orthopaedics, incurring costs that exceed half a billion dollars annually.
      • Prodromos C.
      • Brown C.
      • Fu F.H.
      • et al.
      The Anterior Cruciate Ligament: Reconstruction And Basic Science.
      The aim of ACLR is to regain functional stability of the knee, allowing patients to return to their preinjury level of activity.
      • Bach B.R.
      ACL Surgery: How to Get It Right the First Time and What to Do if It Fails.
      Although conventional ACLR techniques have been shown to perform well subjectively, rotational control is often lacking. Numerous clinical studies have demonstrated persistent anterolateral rotatory laxity, as shown by a residual positive pivot shift.
      • Yunes M.
      • Richmond J.C.
      • Engels E.A.
      • Pinczewski L.A.
      Patellar versus hamstring tendons in anterior cruciate ligament reconstruction: A meta-analysis.
      • Prodromos C.C.
      • Joyce B.T.
      • Shi K.
      • Keller B.L.
      A meta-analysis of stability after anterior cruciate ligament reconstruction as a function of hamstring versus patellar tendon graft and fixation type.
      • Mohtadi N.
      • Chan D.
      • Barber R.
      • Oddone Paolucci E.
      A randomized clinical trial comparing patellar tendon, hamstring tendon, and double-bundle ACL reconstructions: Patient-reported and clinical outcomes at a minimal 2-year follow-up.
      • Mohtadi N.G.
      • Chan D.S.
      • Dainty K.N.
      • Whelan D.B.
      Patellar tendon versus hamstring tendon autograft for anterior cruciate ligament rupture in adults.
      Biomechanical assessments have further demonstrated an inability to restore normal tibial rotation.
      • Ristanis S.
      • Giakas G.
      • Papageorgiou C.D.
      • Moraiti T.
      • Stergiou N.
      • Georgoulis A.D.
      The effects of anterior cruciate ligament reconstruction on tibial rotation during pivoting after descending stairs.
      ,
      • Tashman S.
      • Collon D.
      • Anderson K.
      • Kolowich P.
      • Anderst W.
      Abnormal rotational knee motion during running after anterior cruciate ligament reconstruction.
      Furthermore, high graft failure rates in young individuals, particularly female patients, have been reported in those returning to contact pivoting sports.
      • Mohtadi N.
      • Chan D.
      • Barber R.
      • Oddone Paolucci E.
      A randomized clinical trial comparing patellar tendon, hamstring tendon, and double-bundle ACL reconstructions: Patient-reported and clinical outcomes at a minimal 2-year follow-up.
      ,
      • Lind M.
      • Menhert F.
      • Pedersen A.B.
      Incidence and outcome after revision anterior cruciate ligament reconstruction results from the Danish Registry for Knee Ligament Reconstructions.
      • Kaeding C.C.
      • Pedroza A.D.
      • Reinke E.K.
      • et al.
      Risk factors and predictors of subsequent ACL injury in either knee after ACL reconstruction prospective analysis of 2488 primary ACL reconstructions from the MOON cohort.
      • Kaeding C.C.
      • Aros B.
      • Pedroza A.
      • et al.
      Allograft versus autograft anterior cruciate ligament reconstruction predictors of failure from a MOON prospective longitudinal cohort.
      • Magnussen R.A.
      • Lawrence J.T.R.
      • West R.L.
      • Toth A.P.
      • Taylor D.C.
      • Garrett W.E.
      Graft size and patient age are predictors of early revision after anterior cruciate ligament reconstruction with hamstring autograft.
      The combination of patients exhibiting poor rotational stability and greater failure rates in young patients is suggestive that further investigational work is required to re-establish normal knee joint kinematics following ACLR.
      The recent interest in the anterolateral complex (ALC) has led to a greater focus on the anterolateral extra-articular secondary stabilizers of the knee.
      • Getgood A.
      • Brown C.
      • Lording T.
      • et al.
      The anterolateral complex of the knee: results from the International ALC Consensus Group Meeting.
      Numerous biomechanical studies have demonstrated the important role that the structures of the ALC have in controlling tibial internal rotation. These include the deep and superficial tract of the iliotibial band and its Kaplan fiber attachment to the distal femur, the anterolateral ligament, and the lateral meniscus.
      • Musahl V.
      • Rahnemai-Azar A.A.
      • Costello J.
      • et al.
      The influence of meniscal and anterolateral capsular injury on knee laxity in patients with anterior cruciate ligament injuries.
      This work has led to a renewed interest in ALC reconstructions as a method to regain control of persistent anterolateral rotatory laxity following ACLR; however, definitive evidence as to the clinical efficacy of these reconstructions is lacking.
      Several systematic reviews have been published clearly showing that the addition of an ALC procedure, such as a lateral extra-articular tenodesis (LET), has a significant effect on controlling the pivot shift when combined with an ACLR.
      • Devitt B.M.
      • Bell S.W.
      • Ardern C.L.
      • et al.
      The role of lateral extra-articular tenodesis in primary anterior cruciate ligament reconstruction: A systematic review with meta-analysis and best-evidence synthesis.
      • Hewison C.E.
      • Tran M.N.
      • Kaniki N.
      • Remtulla A.
      • Bryant D.
      • Getgood A.M.
      Lateral Extra-articular tenodesis reduces rotational laxity when combined with anterior cruciate ligament reconstruction: A systematic review of the literature.
      • Song G.Y.
      • Hong L.
      • Zhang H.
      • Zhang J.
      • Li Y.
      • Feng H.
      Clinical outcomes of combined lateral extra-articular tenodesis and intra-articular anterior cruciate ligament reconstruction in addressing high-grade pivot-shift phenomenon.
      However, the studies that have been included in these reviews are subject to selection bias and confounded by a heterogenous selection of surgical techniques with varying outcome.
      To determine whether the addition of LET to ACLR would reduce ACL graft failure rates and improve anterolateral rotatory laxity, we designed a pragmatic, methodically rigorous trial to compare outcomes between ACLR augmented with a LET to ACLR alone in patients who were deemed at high risk of graft failure (Stability Study). A clinically and statistically significant reduction in clinical ACLR failure, defined as graft rupture or persistent asymmetric rotatory laxity (40% relative risk reduction) or graft rupture alone (66% relative risk reduction) was observed.
      • Getgood A.M.J.
      • Bryant D.M.
      • Litchfield R.
      • et al.
      Lateral extra-articular tenodesis reduces failure of hamstring tendon autograft anterior cruciate ligament reconstruction: 2-Year outcomes from the STABILITY study randomized clinical trial.
      However, because of past studies reporting increased pain and potential over constraint of the lateral compartment,
      • Anderson A.F.
      • Snyder R.B.
      • Lipscomb Jr., A.B.
      Anterior cruciate ligament reconstruction. A prospective randomized study of three surgical methods.
      ,
      • O'Brien S.J.
      • Warren R.F.
      • Wickiewicz T.L.
      • et al.
      The iliotibial band lateral sling procedure and its effect on the results of anterior cruciate ligament reconstruction.
      there remains a concern that the LET could have a detrimental effect to recovery and subsequent functional performance. The purpose of this study was to assess the functional outcomes of patients included in the Stability Study randomized controlled trial comparing ACLR alone with ACLR and LET at 6, 12, and 24 months postoperatively. We hypothesized that there would be no difference in Limb Symmetry Index (LSI) between patients undergoing ACLR with an LET compared with those undergoing ACLR alone at 6 months but that patients in the ACL plus LET group would perform better on the hop test at 12 months postoperative due to increased rotational control.

      Methods

      The Stability Study (Clinical Trials.gov: NCT02018354) is a pragmatic multicenter, randomized clinical trial involving 7 centers in Canada and 2 centers in Europe. Local ethics approval was obtained from all participating centers following full board review for the use of human participants (IRB: Western University IRB #104524). A full description of the study methods was previously published.
      • Getgood A.
      • Bryant D.
      • Firth A.
      • Stability G.
      The Stability study: A protocol for a multicenter randomized clinical trial comparing anterior cruciate ligament reconstruction with and without Lateral Extra-articular Tenodesis in individuals who are at high risk of graft failure.
      To summarize, patients were eligible to participate in the study if they (1) had an ACL-deficient knee requiring surgical reconstruction; (2) were skeletally mature; (3) were no more than 25 years of age at the time of surgery; and (4) had 2 or more of the following: (a) participated in a competitive pivoting sport; (b) had a positive pivot shift of grade 2 or higher; or (c) had generalized ligamentous laxity (Beighton score
      • Beighton P.H.
      • Horan F.
      Orthopaedic aspects of the Ehlers-Danlos syndrome.
      of 4 or greater) or had genu recurvatum greater than 10°. Patients were excluded if they (1) had undergone previous ACL reconstruction on either knee; (2) required bilateral ACL reconstruction; (3) required surgical repair or reconstruction of the posterior cruciate ligament, medial collateral ligament, lateral collateral ligament, or posterolateral corner; (4) had a symptomatic articular cartilage defect requiring treatment other than debridement; or (5) had greater than 3 degrees of asymmetric varus alignment.
      Randomization occurred in the operating theater following confirmation of eligibility by the surgeon through diagnostic arthroscopy of the knee joint. Patients were randomized in permuted block sizes of 2 and 4 in a one-to-one ratio by a computer (Empower Health Research, London, Ontario, Canada; www.empowerhealthresearch.ca) into 1 of 2 groups: (1) ACL reconstruction with lateral extra-articular tenodesis (experimental) or (2) ACL reconstruction alone (control). Randomization was stratified by surgeon, sex, and whether a meniscal repair (including root repair) requiring a change in postoperative rehabilitation was performed.

      Surgical Procedures

      All patients received a traditional anatomic ACL reconstruction using an autologous hamstring graft (semitendinosus and gracilis) in a standardized fashion across all sites. Semitendinosus was tripled to increase the graft diameter if a 4-strand graft was less than 8 mm. Femoral tunnels were drilled using an anteromedial portal technique, with femoral suspensory graft fixation. Tibial fixation was provided by an interference screw and/or tibial screw post.
      The LET procedure used was a modification of the Lemaire technique
      • Lemaire M.
      • Combelles F.
      Technique actuelle de plastie ligamentaire pour rupture ancienne du ligament croisé antérieur.
      and the procedure was standardized across all centers (Fig 1). An oblique skin incision between the lateral epicondyle and Gerdy’s tubercle measuring approximately 5 cm was made. A 1-cm by 8-cm strip of the posterior half of the iliotibial band was fashioned, preserving the distal Gerdy’s tubercle attachment. A No. 1 VICRYL whip suture was applied to the free end. The graft was then tunneled under the lateral collateral ligament and attached to the femur on the metaphyseal flare of the lateral femoral condyle just anterior to the distal Kaplan fiber attachment with a Richards Staple (Smith & Nephew, Andover, MA). Fixation was performed with the knee between 60° and 70° flexion and neutral rotation. Minimal tension was applied to the graft. The free end of the graft was then looped back onto itself and sutured using the No. 1 VICRYL suture.
      Figure thumbnail gr1
      Fig 1Lateral extra-articular tenodesis procedure. (A) Right knee at 90° of flexion demonstrating the position of a 5- to 6-cm incision placed just posterior to the lateral femoral epicondyle. (B) A 1-cm wide × 8-cm long strip of the posterior half of the iliotibial band is fashioned leaving the attachment at Gerdy’s tubercle intact. (C) The whip stitched free end of the graft is passed deep to the LCL close to its femoral attachment. (D) The graft is attached to the metaphyseal flare of the lateral femoral condyle in close proximity to the distal Kaplan fiber attachment. The graft is fixated with a Richards staple (Smith & Nephew, Andover, MA) with the knee held at 60 to 70° of flexion, neutral rotation, with minimal tension applied to the graft. The graft is then folded back on itself and sutured. (LCL, lateral collateral ligament.)
      All patients followed a similar postoperative rehabilitation protocol with a focus placed on early range of motion and weight bearing as tolerated. Postoperative rehabilitation braces were not routinely used unless provided to restrict range of motion following meniscus repair. Functional bracing was not used.

      Outcome Measures

      Functional testing was completed by 3 of the 7 participating centers according to the availability of infrastructure and personnel. The primary outcome of LSI was calculated using the combination of 4-hop tests as described by Noyes et al.
      • Noyes F.R.
      • Barber S.D.
      • Mangine R.E.
      Abnormal lower limb symmetry determined by function hop tests after anterior cruciate ligament rupture.
      The LSI expresses the test performance of the operative limb as a percentage of the nonoperative limb. A higher LSI indicates a greater level of function for the operative limb. The hop test has demonstrated validity and excellent test–retest reliability.
      • Reid A.
      • Birmingham T.B.
      • Stratford P.W.
      • Alcock G.K.
      • Giffin J.R.
      Hop testing provides a reliable and valid outcome measure during rehabilitation after anterior cruciate ligament reconstruction.
      All hops were performed twice on the noninjured limb and twice on the postoperative limb, and the average of the 2 trials was used in the analysis. The hop test was administered at 6, 12, and 24 months postoperatively by a trained kinesiologist at each center who was blinded to the operative procedure via a tubigrip worn over the operative limb.
      Secondary functional outcome measures included the Four-Item Pain Intensity Measure (P4), a patient-reported 4-item questionnaire,
      • Spadoni G.F.
      • Stratford P.W.
      • Solomon P.E.
      • Wishart L.R.
      Development and cross-validation of the P4: a self-report pain intensity measure.
      and the Lower Extremity Functional Scale (LEFS).
      • Binkley J.M.
      • Stratford P.W.
      • Lott S.A.
      • Riddle D.L.
      The Lower Extremity Functional Scale (LEFS): Scale development, measurement properties, and clinical application.
      The P4 queries pain intensity in the morning, afternoon, evening, and with activity over the past 2 days. Each item is measured using an ordinal scale ranging from 0 (no pain) to 10 (pain as bad as it can be). Scores are calculated by adding the individual scores from each item, to give a maximum score of 40. The P4 has shown a test–retest reliability of 0.78 and good longitudinal validity (0.63).
      • Spadoni G.F.
      • Stratford P.W.
      • Solomon P.E.
      • Wishart L.R.
      The evaluation of change in pain intensity: a comparison of the P4 and single-item numeric pain rating scales.
      Patients completed the P4 questionnaire before surgery (baseline) and at 3, 6, 12, and 24 months postoperatively.
      The LEFS is a self-report functional measure for patients with lower-extremity orthopaedic conditions. This scale consists of 20 functional items with 5 response options for each item. Response options range from 0 (extreme difficulty or unable to perform activity) to 4 (no difficulty). The patient’s score is tallied out of a maximum of 80 points, where a high score indicates a high level of function. The LEFS is a valid measure of function, is responsive to change, and is highly reliable.
      • Yeung T.S.M.
      • Wessel J.
      • Stratford P.
      • MacDermid J.
      Reliability, validity, and responsiveness of the lower extremity functional scale for inpatients of an orthopaedic rehabilitation ward.
      Patients completed the LEFS before surgery (baseline) and at 6, 12, and 24 months postoperatively.
      Quadriceps and hamstrings strength were measured before surgery (baseline) and at 6, 12, and 24 months postoperatively using the Biodex System 3 PRO computerized isokinetic dynamometer (Biodex Medical Inc., Shirley, NY). Strength measurements were performed in a standardized fashion across all sites. The patient wore a tubigrip on the operative limb to conceal group allocation (LET vs no LET). The patient was seated with his/her back against a backrest oriented at 80° above the horizontal and his/her hips in approximately 80° of flexion. Two seatbelts securing the patient’s pelvis were oriented diagonally from the dynamometer seat, across the anterior superior iliac spines and over the shoulders to the backrest. The axis of rotation of the dynamometer lever arm was positioned coaxial to the lateral femoral epicondyle. Patients performed the test first with the noninjured limb then again with the injured limb. On each side, they performed four practice contractions to familiarize themselves with the testing apparatus. Patients were given a 30-second rest period between the practice contractions and the actual test. Each test consisted of 6 consecutive alternating knee flexion (3 repetitions) and extension (3 repetitions) movements and was assessed using the maximal concentric muscle actions at an angular velocity of 90°/s. If the variance of the quadriceps or hamstrings contractions were greater than 10%, the test was repeated following a 60-second rest period. Peak torque (Newton meters) and average power (Watts) measurements were recorded and strength scores were calculated by dividing the affected limb by the unaffected limb to get a percentage of function for both flexion and extension. Hamstrings to quadriceps ratios (percentage) were also presented for the affected limb. For all measurements a higher score indicates a higher level of function. The Biodex System 3 has been shown to perform with acceptable mechanical reliability and validity.
      • Drouin J.M.
      • Valovich-mcLeod T.C.
      • Shultz S.J.
      • Gansneder B.M.
      • Perrin D.H.
      Reliability and validity of the Biodex system 3 pro isokinetic dynamometer velocity, torque and position measurements.

      Sample Size

      The patients in this current study represent a subset of patients from the Stability Study,
      • Getgood A.M.J.
      • Bryant D.M.
      • Litchfield R.
      • et al.
      Lateral extra-articular tenodesis reduces failure of hamstring tendon autograft anterior cruciate ligament reconstruction: 2-Year outcomes from the STABILITY study randomized clinical trial.
      where the primary outcome, and thus the sample size calculation, focused on the dichotomous outcome of failure (yes/no). Since dichotomous outcomes require exponentially larger samples than outcomes measured using a continuous metric (LSI, strength, patient-reported outcomes), we were well-powered to evaluate functional outcomes at 6 months (power = 99.6%), 12 months (power = 99.5%), and 24 months (power = 99.1%).

      Statistical Analysis

      All data analyses were performed using IBM SPSS Statistics, version 24 (IBM Corp., Armonk, NY).
      Descriptive statistics were used to present the demographic characteristics of the patients by group using means and standard deviations for continuous variables (age, height, weight, time from injury to surgery) and proportions for nominal variables (sex, operative limb, limb dominance, mechanism of injury, sport participation at the time of injury and associated injuries). All continuous data (LSI from the hop test, P4, strength, and LEFS) are presented as a mean ± standard deviation. Since a large number of patients were unable or not permitted to perform the hop test at 6 months postoperatively, we also presented the proportion of patients in each group who could not complete the test and used a χ2 test to determine whether there was a statistically significant difference between the 2 groups. For any outcome where we were able to collect a preoperative measure (P4, strength, and LEFS), we conducted an analysis of covariance where the preoperative score served as the covariate, the postoperative score served as the dependent variable and the study group served as the independent variable. For A P < .05 was considered to be statistically significant. To compare the approaches over time, we presented a boxplot of the median scores with interquartile range, minimum and maximum scores, and outliers for each outcome over time.

      Results

      A CONSORT (Consolidated Standards of Reporting Trials) flowchart detailing patient eligibility and recruitment is outlined in Figure 2. Of the 618 patients randomized from Stability, a total of 356 patients were included in the study because they were from a center with sufficient infrastructure to collect functional data (180 ACL and 176 ACL plus LET). Hop testing was performed at The Fowler Kennedy Sport Medicine Clinic and Banff Sport Medicine Clinic (n = 336), whereas isokinetic strength testing was performed only at the Fowler Kennedy Sport Medicine Clinic and Pan Am Clinic (n = 215). Patient demographics, graft characteristics, and meniscal and articular cartilage findings were similar between the 2 groups (Table 1).
      Figure thumbnail gr2
      Fig 2CONSORT (Consolidated Standards of Reporting Trials) flow chart indicating participant inclusion through the trial. (ACLR, anterior cruciate ligament reconstruction; LEFS, Lower Extremity Functional Scale; LET, lateral extra-articular tenodesis.)
      Table 1Baseline Demographics for Patients Undergoing ACLR Alone or With an LET
      CharacteristicACLR AloneACLR + LETP Value
      Sex, male, n (%)79 (45.9)75 (44.4).77
      Age, y, mean ± SD18.7 ± 3.219.0 ± 3.1.35
      Height, cm, mean ± SD167.1 ± 33.1170.1± 20.7.33
      Weight, kg, mean ± SD71.9 ± 15.471.8 ± 14.7.98
      BMI, kg/m2, mean ± SD22.9 ± 5.723.8 ± 4.7.10
      Beighton score, 0–9, %, mean ± SD3.2 ± 2.63.0 ± 2.80.57
      Months between injury and surgery, mean ± SD8.1 ± 18.99.3 ± 16.7.41
      Operative limb, dominant, n (%)95 (55.2)81 (47.9).18
      Mechanism of injury, contact, n (%)22 (17.6)24 (19.8).65
      Sport played at time of injury, n (%)
       Soccer47 (28.1)78 (47.6).38
       Football12 (7.2)17 (10.4)
       Gymnastics34 (20.4)17 (10.4)
       Squash14 (8.4)12 (7.3)
       Other60 (35.9)40 (24.4)
      Smoking status, n (%).57
       Current smoker4 (2.3)2 (1.2)
       Ex-smoker11 (6.4)8 (4.7)
       Nonsmoker157 (91.3)159 (94.1)
      Graft source, n (%).54
       Semitendinosis and gracilis166 (96.5)165 (97.6)
       Semitendinosis6 (3.5)4 (2.4)
      Graft diameter, mm, median (min, max)8.0 (6, 10)8.0 (6, 10).32
      Meniscal pathology, n (%)
       Medial76 (44.2)86 (50.9).22
       Lateral82 (47.7)72 (42.6).35
       Both33 (19.2)39 (23.1).38
      Change in rehab due to meniscus repair, n (%)14 (18.4)19 (22.1).84
      Chondral defect, n (%)30 (17.4)24 (14.2).41
      ACL, anterior cruciate ligament; CI, confidence interval; LET, lateral extra-articular tenodesis; SD, standard deviation.
      At 6 months, 40 patients in the ACL alone group (31.5%) and 40 patients in the ACL plus LET group (31.5%) were unable to perform the hop test (P = 1.00) (Table 2). At 12 months postoperatively, 25 patients in the ACL alone group (16.2%) and 27 patients in the ACL plus LET group (17.6%) were unable or not permitted to perform the hop test (P = .76). At 24 months, 21 patients in the ACL alone group (13.7%) and 23 patients in the ACL plus LET group (14.6%) were unable to perform the hop test (P = .87).
      Table 2Reasons That Patients Were Unable to Complete Functional Hop Testing
      Reason6 Months12 Months24 Months
      ACL n = 40LET n = 40ACL n = 25LET n = 27ACL n = 21LET n = 23
      Graft failure015373
      Contralateral ACL rupture002133
      Other adverse event (knee)122231
      Discouraged by clinician
      Kinesiologist, physical therapist, or surgeon.
      853220
      Valgus collapse first attempt682314
      Patient fear/apprehension5112220
      Pain and/or stiffness141141129
      Fatigue100201
      Inappropriate footwear200000
      No kinesiologist available212011
      Other health condition203101
      ACL, anterior cruciate ligament; LET, lateral extra-articular tenodesis.
      Kinesiologist, physical therapist, or surgeon.
      Of the patients who were able to complete the test at 6 months postoperatively (n = 255), 12 months postoperatively (n = 265), and 24 months postoperatively (n = 263), there was no statistical difference in LSI between groups (Fig 3).
      Figure thumbnail gr3
      Fig 3Limb Symmetry Index (LSI) hop test scores at 6, 12, and 24 months for patients undergoing ACLR with or without a LET. Box plots represent unadjusted group medians (solid black line) with interquartile range (colored box), min, max values (whiskers). Outliers are plotted as solid dots (known) or asterisks (unknown). (ACLR, anterior cruciate ligament reconstruction; LET, lateral extra-articular tenodesis.)
      There was a statistically significant difference between groups in the LEFS score at 3 (P = .01) and 6 months (P = .02) postoperative, but these differences were not observed by 12 months postoperative (Fig 4). Both groups reported improvements in pain and self-reported functional ability at each time point postoperatively.
      Figure thumbnail gr4
      Fig 4LEFS scores for patients undergoing ACLR with or without an LET. Box plots represent unadjusted group medians (solid black line) with interquartile range (colored box), min, max values (whiskers). Outliers are plotted as solid dots (known) or asterisks (unknown). Patients who suffered an adverse event, including those with graft failure and/or contralateral failure, are included in this analysis, which explains the greater proportion of outliers at the later visit time points after patients are exposed to sport and more susceptible to ACL rupture. (ACL, anterior cruciate ligament; ACLR, anterior cruciate ligament reconstruction; LEFS, Lower Extremity Functional Scale; LET, lateral extra-articular tenodesis.)
      A statistically significant increase was observed in the P4 pain score at 3 months postoperatively in the ACL plus LET group (Fig 5), although its clinical significance is questionable. These differences resolved at 12 and 24 months.
      Figure thumbnail gr5
      Fig 5P4 pain scores for patients undergoing ACLR with or without an LET. Box plots represent unadjusted group medians (solid black line) with interquartile (colored box), min, max values (whiskers). Outliers are plotted as solid dots (known) or asterisks (unknown). Patients who suffered an adverse event, including those with graft failure and/or contralateral failure, are included in this analysis, which explains the greater proportion of outliers at the later visit time points after patients are exposed to sport and more susceptible to ACL rupture. (ACL, anterior cruciate ligament; ACLR, anterior cruciate ligament reconstruction; LET, lateral extra-articular tenodesis; P4, Four-Item Pain Intensity Measure.)
      The ACL alone group had improved quadriceps strength postoperatively but had reduced hamstring strength and hamstrings to quadriceps ratio compared to their baseline scores (Table 3).
      Table 3Quadriceps and Hamstrings Measurements for Patients Undergoing ACL Reconstruction With and Without an LET (Adjusted for Preoperative Scores on the Noninjured Side)
      Strength Measure, %ACLR Alone, mean ± SEACLR + LET, mean ± SEMean Difference (95% CI)P Value
      QI peak torque
       Preoperative74.9 ± 2.275.2 ± 1.8–0.3 (–5.8 to 5.3).93
       6 mo79.4 ± 1.674.3 ± 1.45.1 (0.5 to 9.6).03
       12 mo90.2 ± 1.486.9 ± 1.43.3 (–0.7 to 7.4).11
       24 mo90.5 ± 1.690.9 ± 1.5–0.4 (–4.8 to 4.0).87
      QI average power
       Preoperative76.9 ± 1.877.1 ± 1.9-0.2 (–6.3 to 5.8).94
       6 mo81.0 ± 1.575.6 ± 1.55.4 (1.2 to 9.6).01
       12 mo89.9 ± 1.487.9 ± 1.42.0 (–2.0 to 6.0).32
       24 mo91.0 ± 1.690.1 ± 1.60.9 (–3.5 to 5.4).60
      HTI peak torque
       Preoperative85.6 ± 2.182.9 ± 2.12.6 (–6.1 to 11.4).55
       6 mo85.2 ± 1.782.5 ± 1.73.2 (–1.4 to 7.9).17
       12 mo88.1 ± 1.686.8 ± 1.61.3 (–3.3 to 5.8).59
       24 mo92.0 ± 1.690.0 ± 1.52.1 (–2.3 to 6.5).35
      HTI average power
       Preoperative88.4 ± 7.981.3 ± 2.37.1 (–9.1 to 23.3).39
       6 mo78.9 ± 1.674.4 ± 1.64.5 (0.1 to 9.0).05
       12 mo82.5 ± 1.581.6 ± 1.50.9 (–3.3 to 5.1).68
       24 mo86.8 ± 1.685.1 ± 1.61.7 (–2.8 to 6.2).45
      HTI/QI ratio (involved)
       Preoperative56.8 ± 2.055.7 ± 1.21.2 (–3.4 to 5.8).62
       6 mo55.6 ± 1.456.9 ± 1.4–1.3 (–5.3 to 2.7).53
       12 mo51.1 ± 1.253.2 ± 1.2–2.1 (–5.5 to 1.3).22
       24 mo52.2 ± 1.252.0 ± 1.20.2 (–3.1 to 3.6).90
      NOTE. Bold values are statistically significant.
      ACL, anterior cruciate ligament; CI, confidence interval; LET, lateral extra-articular tenodesis; QI, quadriceps index; SE, standard error.
      The ACL plus LET group scored lower on all variables postoperatively at 6 months compared with their baseline scores except for the hamstrings to quadriceps ratio, which remained similar. By 12 months these scores increased past baseline. At 6 months postoperative, the adjusted mean difference between the 2 groups for both peak torque and average power in the quadriceps muscles was statistically significant in favor of the ACL alone group. These changes resolved at 12 months, with no differences remaining at 24 months.

      Discussion

      The most important finding of this study is that patients undergoing ACLR augmented with LET do not result in an inferior functional outcome compared with those treated with ACLR alone. Although a greater amount of pain in the early postoperative phase (3 months) was observed, as well as a delay to quadriceps strength recovery and reduction in LEFS, these differences were small and transient, resolving by 6 months and 12 months respectively.
      The decrease in quadriceps strength may be a direct result of the LET procedure. To attach the LET to the femur, the vastus lateralis muscle is retracted, which may damage the muscle. Interestingly, Strum et al.
      • Strum G.M.
      • Fox J.M.
      • Ferkel R.D.
      • et al.
      Intraarticular versus intraarticular and extraarticular reconstruction for chronic anterior cruciate ligament instability.
      reported significantly greater thigh atrophy in the ACLR plus LET compared to ACLR alone.
      Further differences between the groups were observed for pain determined by the P4, and subjective function as determined by the LEFS at 3 months. Both of these measures normalized from 6 months onwards. Three previous studies comparing ACLR plus LET with ACLR alone, assessed pain. Vadalà et al.
      • Vadalà A.P.
      • Iorio R.
      • De Carli A.
      • et al.
      An extra-articular procedure improves the clinical outcome in anterior cruciate ligament reconstruction with hamstrings in female athletes.
      found no differences between the groups using a visual analog scale, whereas Noyes et al.
      • Noyes F.R.
      • Barber S.D.
      The effect of an extra-articular procedure on allograft reconstructions for chronic ruptures of the anterior cruciate ligament.
      found no differences using a 10-point scale. Dejour et al.
      • Dejour D.
      • Vanconcelos W.
      • Bonin N.
      • Saggin P.R.F.
      Comparative study between mono-bundle bone-patellar tendon-bone, double-bundle hamstring and mono-bundle bone-patellar tendon-bone combined with a modified Lemaire extra-articular procedure in anterior cruciate ligament reconstruction.
      also found no difference between the 2 groups in regards to anterior knee pain when classified as present or absent. None of these other studies used the P4 pain scale, which may be a more sensitive method to pick up between group differences, as it documents presence of pain at a variety of times throughout the day and over the previous 2 days of activity. Similarly, no other studies comparing ACLR plus LET to ACLR alone have used the LEFS. Noyes et al.
      • Noyes F.R.
      • Barber S.D.
      The effect of an extra-articular procedure on allograft reconstructions for chronic ruptures of the anterior cruciate ligament.
      used their own subjective assessment of function and found no differences between the 2 groups. The results of both the P4 and the LEFS suggest that the LET procedure results in a greater degree of pain and subsequent reduction in subjective function at 3 months, which may be expected based on the extra incision, harvest-site morbidity, and surgical procedure involved.
      It should be noted however, that although these differences reached statistical significance, their clinical relevance is questioned. Previous studies have found LSI to be directly correlated with quadriceps strength symmetry, with patients with lower quadriceps strength symmetries performing worse on functional tests such as the hop test.
      • Palmieri-Smith R.M.
      • Lepley L.K.
      Quadriceps strength asymmetry after anterior cruciate ligament reconstruction alters knee joint biomechanics and functional performance at time of return to activity.
      ,
      • English R.
      • Brannock M.
      • Chik W.T.
      • Eastwood L.S.
      • Uhl T.
      The relationship between lower extremity isokinetic work and single-leg functional hop-work test.
      Contrary to this, we found that patients who underwent ACLR alone had a mean total LSI of 91.0%, 97.0%, and 98.7% at 6, 12, and 24 months, respectively, compared with 89.3%, 96.2%, and 99.3% in the LET group, which was not statistically significantly between groups at any time point. Importantly, previously published studies consider a LSI of 85% or greater to be normal following ACLR,
      • Barber S.D.
      • Noyes F.R.
      • Mangine R.E.
      • McCloskey J.W.
      • Hartman W.
      Quantitative assessment of functional limitations in normal and anterior cruciate ligament-deficient knees.
      although some authors advocate for a LSI greater than 90% for patients to successfully return to sport.
      • Munro A.G.
      • Herrington L.C.
      Between-session reliability of four hop tests and the agility T-test.
      In our study, patients who received ACLR alone surpassed these recommendations at all time points, whereas the ACLR plus LET reached this threshold by the 12-month time point.
      This current study is unique for its methodologic rigor and focus on functional outcomes. Numerous studies have compared ACLR plus LET with ACLR alone; however, only 3 studies to date have included functional outcomes.
      • Noyes F.R.
      • Barber S.D.
      The effect of an extra-articular procedure on allograft reconstructions for chronic ruptures of the anterior cruciate ligament.
      ,
      • Roth J.H.
      • Kennedy J.C.
      • Lockstadt H.
      • McCallum C.L.
      • Cunning L.A.
      Intra-articular reconstruction of the anterior cruciate ligament with and without extra-articular supplementation by transfer of the biceps femoris tendon.
      ,
      • Oni O.O.A.
      • Crowder E.
      A comparison of isokinetics and muscle strength ratios following intra-articular and extra-articular reconstructions of the anterior cruciate ligament.
      In 1987, Roth et al.
      • Roth J.H.
      • Kennedy J.C.
      • Lockstadt H.
      • McCallum C.L.
      • Cunning L.A.
      Intra-articular reconstruction of the anterior cruciate ligament with and without extra-articular supplementation by transfer of the biceps femoris tendon.
      retrospectively compared a cohort of patients who underwent ACLR combined with a transfer of the superficial portion of the biceps femoris tendon (n = 43), an extra-articular procedure advocated as a dynamic back up to ACLR, to a cohort of those who had undergone ACLR alone (n = 50). Although the biceps tendon transfer differs greatly from the iliotibial band tenodesis used in this study, both are extra-articular procedures advocated to augment intra-articular reconstructions of the ACL to address rotational deficiency. At a minimum of 2 years postoperatively, they reported no differences between the 2 groups in LSI for the single leg hop for distance. The ACLR plus biceps tendon advancement group had a mean index of 89.7%, whereas the ACLR alone group had a mean index of 89.6%. These scores are similar to the indices we calculated for the single leg hop test at 6 months postoperatively. Roth et al.
      • Roth J.H.
      • Kennedy J.C.
      • Lockstadt H.
      • McCallum C.L.
      • Cunning L.A.
      Intra-articular reconstruction of the anterior cruciate ligament with and without extra-articular supplementation by transfer of the biceps femoris tendon.
      also reported isokinetic strength measurements at 180°/second; however, they reported power and work measurements for the operative limb only. They found no statistically significant differences between the groups. In our study, we chose to report the measurements of the operative limb as a percentage of the measurements of the non-operative limb rather than mean scores for the operative limb alone. Strength asymmetry following ACLR has been shown to correlate with poor subjective outcomes, poor functional performance, and altered lower limb mechanics during gait
      • Palmieri-Smith R.M.
      • Lepley L.K.
      Quadriceps strength asymmetry after anterior cruciate ligament reconstruction alters knee joint biomechanics and functional performance at time of return to activity.
      ; therefore, symmetry provides more information than group mean power and mean work measurements alone.
      Anderson et al.
      • Anderson A.F.
      • Snyder R.B.
      • Lipscomb Jr., A.B.
      Anterior cruciate ligament reconstruction. A prospective randomized study of three surgical methods.
      also found similar results when comparing patients who were randomized to 1 of 3 groups: ACLR with patellar tendon graft (n = 35), ACLR with hamstring graft (n = 35), and ACLR with hamstring graft plus a Losee LET (n = 35). However, they used speeds of 60 and 180°/seconds and reported results at an average of 4.8 years postoperatively. They found a similar trend, with patients in the ACLR plus LET group having lower quadriceps symmetry than the other 2 groups; however, these differences were not statistically significant.
      In 1991, Noyes and Barber
      • Noyes F.R.
      • Barber S.D.
      The effect of an extra-articular procedure on allograft reconstructions for chronic ruptures of the anterior cruciate ligament.
      compared a cohort of patients undergoing ACLR with a patellar tendon allograft plus an iliotibial band LET (n = 40) with a group of patients undergoing ACLR with a patellar tendon allograft alone (n = 64). Isokinetic strength measurements at 450°/second were performed on 30 patients from the ACLR plus LET group (75%) and 39 patients from the ACLR alone group (61%). They found that 83% of patients in the ACLR plus LET group and 79% of patients in the ACLR alone had mild to no deficits in both quadriceps and hamstrings measurements (defined as zero to 20% deficit). These differences were not statistically significant. These results differ from our results as the majority of patients in this study had greater than 20% deficits. This is likely because of the difference in the time points of the two analyses, which was an average of 35 months postoperative in the Noyes and Barber study compared to 6 months postoperative in this analysis.
      Functional measurements including LSI, muscle strength symmetry, and hamstring to quadriceps ratio are useful tools that can be used to help determine when a patient is ready to return to sport.
      • Palmieri-Smith R.M.
      • Lepley L.K.
      Quadriceps strength asymmetry after anterior cruciate ligament reconstruction alters knee joint biomechanics and functional performance at time of return to activity.
      ,
      • Munro A.G.
      • Herrington L.C.
      Between-session reliability of four hop tests and the agility T-test.
      ,
      • Rosene J.M.
      • Fogarty T.D.
      • Mahaffey B.L.
      Isokinetic hamstrings: Quadriceps ratios in intercollegiate athletes.
      ,
      • Salmon L.
      • Russell V.
      • Musgrove T.
      • Pinczewski L.
      • Refshauge K.
      Incidence and risk factors for graft rupture and contralateral rupture after anterior cruciate ligament reconstruction.
      Therefore, these measurements are useful when comparing different techniques of ACLR and can provide surgeons with the information needed to make an informed decision when treating the ACL deficient knee, particularly in young and athletic individuals intending to return to sport. What this study does not address is whether the same functional outcomes would be expected for any type of anterolateral reconstruction, such as the recently published ALL reconstructions.
      • Sonnery-Cottet B.
      • Saithna A.
      • Cavalier M.
      • et al.
      Anterolateral ligament reconstruction is associated with significantly reduced acl graft rupture rates at a minimum follow-up of 2 years.
      • Wagih A.M.
      • Elguindy A.M.
      Percutaneous reconstruction of the anterolateral ligament of the knee with a polyester tape.
      • Chahla J.
      • Menge T.J.
      • Mitchell J.J.
      • Dean C.S.
      • LaPrade R.F.
      Anterolateral ligament reconstruction technique: An anatomic-based approach.
      These techniques have used different grafts and surgical techniques; therefore, it is not clear as to whether the same delay in recovery would be observed.

      Limitations

      The use of the hop test as a primary outcome is a limitation of this study. Although the hop test is often used as a tool to determine when a patient is ready to return to activity, it is a surrogate measure and no study has evaluated the magnitude of the association between a patient’s score on the hop test and subsequent adverse outcomes; likely because it is not feasible to do so (low event rate). Also, patients only completed hop tests if both the surgeon and the kinesiologist felt the patient was fit to complete the test, which may have biased the results. However, no differences in number of patients able to do the test was observed between groups. Furthermore, comparing the hop test with the contralateral limb (LSI) may also create an artificially good score, due to potential deconditioning of the “normal” side.
      • Hiemstra L.A.
      • Webber S.
      • MacDonald P.B.
      • Kriellaars D.J.
      Contralateral limb strength deficits after anterior cruciate ligament reconstruction using a hamstring tendon graft.
      ,
      • Pairot de Fontenay B.
      • Argaud S.
      • Blache Y.
      • Monteil K.
      Contralateral limb deficit seven months after ACL-reconstruction: an analysis of single-leg hop tests.
      The strength testing protocol is another limitation to this study. Most studies examining isokinetic strength measurements following ACLR perform the test at multiple speeds and increasing repetitions. This would have allowed us to examine quadriceps and hamstrings endurance and fatigability rather than only peak torque production. Another limitation is that all centers included in the trial are specialized sport medicine clinics and all surgeons are well experienced in performing ACLRs. Therefore, the results of this study may not be directly translatable to smaller centers with less-experienced surgeons. Lastly, another limitation is the postoperative rehabilitation. Although a standardized protocol was given to all patients, we did not monitor compliance with the protocol.

      Conclusions

      The addition of a LET to ACLR results in slightly increased pain, a mild reduction in quadriceps strength, and reduced subjective functional recovery up to 6 months postoperatively. However, these differences do not have any impact on objective function as measured by hop test LSI.

      Acknowledgments

      Stability Study Group members: London Health Science Centre, Western University, Fowler Kennedy Sport Medicine Clinic, London, Ontario: Alan Getgood, Dianne Bryant, Robert Litchfield, Kevin Willits, Trevor Birmingham, Chris Hewison, Stacey Wanlin, Andrew Firth, Ryan Pinto, Ashley Martindale, Lindsey O’Neill, Morgan Jennings, Michal Daniluk. Fraser Orthopaedic Institute, New Westminster, British Columbia: Dory Boyer, Bob McCormack, Mauri Zomar, Karyn Moon, Raely Moon, Brenda Fan, Bindu Mohan. Banff Sport Medicine, Banff, Alberta: S. Mark Heard, Gregory M. Buchko, Laurie A. Hiemstra, Sarah Kerslake, Jeremy Tynedal. Pan Am Clinic, Winnipeg, Manitoba: Peter MacDonald, Greg Stranges, Sheila Mcrae, LeeAnne Gullett, Holly Brown, Alexandra Legary, Alison Longo, Mat Christian, Celeste Ferguson. University of Calgary, Sport Medicine Centre, Calgary, Alberta: Alex Rezansoff, Nick Mohtadi, Rhamona Barber, Denise Chan, Caitlin Campbell, Alexandra Garven, Karen Pulsifer, Michelle Mayer. McMaster University, Hamilton, Ontario: Devin Peterson, Nicole Simunovic, Andrew Duong, David Robinson, David Levy, Matt Skelly and Ajaykumar Shanmugaraj. Queens University, Kingston, Ontario: Davide Bardana, Fiona Howells, Murray Tough. University Hospitals Coventry Warwickshire NHS Trust, Coventry, United Kingdom: Tim Spalding, Pete Thompson, Andrew Metcalfe, Laura Asplin, Debra Dunne. Antwerp Orthopaedic Center, Ghent, Belgium: Peter Verdonk, Geert Declerq, Kristien Vuylsteke, Mieke Van Have.

      Supplementary Data

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