Cell-based versus corticosteroid injections for knee pain in osteoarthritis: a randomized phase 3 trial.

Various types of cellular injection have become a popular and costly treatment option for patients with knee osteoarthritis despite a paucity of literature establishing relative efficacy to each other or corticosteroid injections. Here we aimed to identify the safety and efficacy of cell injections from autologous bone marrow aspirate concentrate, autologous adipose stromal vascular fraction and allogeneic human umbilical cord tissue-derived mesenchymal stromal cells, in comparison to corticosteroid injection (CSI). The study was a phase 2/3, four-arm parallel, multicenter, single-blind, randomized, controlled clinical trial with 480 patients with a diagnosis of knee osteoarthritis (Kellgren-Lawrence II-IV). Participants were randomized to the three different arms with a 3:1 distribution. Arm 1: autologous bone marrow aspirate concentrate (n = 120), CSI (n = 40); arm 2: umbilical cord tissue-derived mesenchymal stromal cells (n = 120), CSI (n = 40); arm 3: stromal vascular fraction (n = 120), CSI (n = 40). The co-primary endpoints were the visual analog scale pain score and Knee injury and Osteoarthritis Outcome Score pain score at 12 months versus baseline. Analyses of our primary endpoints, with 440 patients, revealed that at 1 year post injection, none of the three orthobiologic injections was superior to another, or to the CSI control. In addition, none of the four groups showed a significant change in magnetic resonance imaging osteoarthritis score compared to baseline. No procedure-related serious adverse events were reported during the study period. In summary, this study shows that at 1 year post injection, there was no superior orthobiologic as compared to CSI for knee osteoarthritis. ClinicalTrials.gov Identifier: NCT03818737.

THE EFFECT OF TIME AND SEX ON POST-ANTERIOR CRUCIATE LIGAMENT RECONSTRUCTION PSYCHOLOGICAL PATIENT REPORTED OUTCOME MEASURE SCORES.

CONTEXT: Low scores on psychological patient reported outcomes measures (PROMs), including the anterior cruciate ligament-return to sport after injury (ACL-RSI) and injury-psychological readiness to return to sport (I-PRRS), after anterior cruciate ligament (ACL) reconstruction (ACLR) have been associated with a maladaptive psychological response to injury and poor prognosis. OBJECTIVE: The purpose of this study was to assess the effect of time post-ACLR and sex on ACL-RSI and I-PRRS scores and generate normative reference curves. It was hypothesized that males would demonstrate higher ACL-RSI and I-PRRS scores than females in the first 1-year post-ACLR. DESIGN: Case series. SETTING: Outpatient sports medicine and orthopedic clinic. PATIENTS: 507 patients post-primary ACLR 12-to-30-years-old with 796 ACL-RSI or I-PRRS scores one or more times between 0- and 1-year post-ACLR (age at ACLR: 17.9 ± 3.0 y). MAIN OUTCOME MEASURES: An honest broker provided anonymous data from our institution's knee injury clinical database. Generalized additive models for location, scale, and shape and generalized least squares analyses were used to assess the effect of time post-ACLR and sex on ACL-RSI and I-PRRS scores. RESULTS: ACL-RSI and I-PRRS scores increased over time post-ACLR, and males had higher scores compared to females up until approximately five months post-ACLR with scores converging thereafter. CONCLUSIONS: Males report higher ACL-RSI and I-PRRS scores compared to females in the initial stages of rehabilitation, but scores converge between sexes at times associated with return to play following ACLR. Normative reference curves can be used to objectively appraise patients' ACL-RSI and I-PRRS scores at any time point post-ACLR. This may lead to timely identification of patients with scores or changes in scores over time post-ACLR associated with a maladaptive psychological response to injury and a poor prognosis and optimized ACLR outcomes.

Arthroscopic Repair of the Acetabular Labrum Using an Anchor-First Modified Toggle Suture Technique.

The goal of acetabular labral repair is to restore stable contact between the labrum and acetabular rim while maintaining the anatomic suction seal. One of the challenges of labral repair is achieving proper in-round repair, so that the labrum contacts the femoral head in the native position. This technique article presents a repair method that allows for enhanced inversion of the labrum to assist with anatomic repair. Our modified toggle suture technique utilizes an anchor-first method and has various distinct technical advantages. We present an efficient and vendor-agnostic technique that allows for straight or curved guides. Similarly, the anchors may be all-suture or hard-anchor designs that accommodate suture sliding. This technique also utilizes a self-retaining hand-tied knot construct to facilitate preventing knots from migrating toward the femoral head or joint space.

Rotational Osteotomy for Femoral Version/Tibial Torsion.

PURPOSE OF REVIEW: The purpose of this review is to discuss the current state of knowledge regarding axial plane deformities in patellofemoral instability, indications and techniques for treatment of those deformities, and outcomes following treatment. RECENT FINDINGS: There is opportunity for more information in the literature on all aspects of axial plane deformities in patellofemoral instability. This includes how to assess axial plane deformities on imaging, what is normal and what is an appropriate goal for correction, what techniques are best used depending on the deformity or concomitant pathology, and larger and more discriminating studies on outcomes. Rotational deformity of both the tibia and femur is an important risk factor to consider as a cause of patellar instability. Recent research has shown that surgical correction of these deformities on either the femoral or tibial side can have a positive effect on outcome in terms of patellar instability and knee pain. Further research, however, is warranted to determine what are normal values for femoral version and tibial torsion, and at what values surgical intervention is warranted.

Retrospective Longitudinal Evaluation of Male Firefighter's Body Composition and Cardiovascular Health.

OBJECTIVE: Describe firefighter body composition and cardiovascular health as a function of age. METHODS: 217 male firefighters with 1922 distinct evaluations over 23-years were included in this retrospective analysis. The firefighters had their height, mass, six-site skin-fold, blood pressure, and resting heart rate measured annually. Linear mixed models were used to analyze the effect of age. Significance was set to P < 0.05. RESULTS: With each 1-year increase in age, mass (0.42 kg, P < 0.001), body mass index (0.13 kg m-2, P < 0.001), body fat percentage (0.18%, P < 0.001), fat mass (0.25 kg, P < 0.001), and fat free mass (0.15 kg, P < 0.001) increased. Systolic blood pressure (-0.09 mm Hg, P = 0.263), diastolic blood pressure (0.05 mm Hg, P = 0.308), and resting heart rate (0.07 beats min-1, P = 0.291) did not change. CONCLUSIONS: Interventions to maintain healthy body composition are critical to reduce sudden cardiovascular related death risk.

Rotational Deformity-When and How to Address Femoral Anteversion and Tibial Torsion.

Rotational deformity is a less common cause of patellar instability than trochlear dysplasia and patella alta. In some cases, rotational deformity is the primary bony factor producing the instability and should be corrected surgically. More research is needed on what are normal values for femoral version and tibial torsion, as well as when the axial plane alignment needs to be corrected. Many tools can be used to evaluate the axial plane and surgeons should be familiar with each of them. Understanding the advantages and disadvantages of each site for osteotomy will help the surgeon choose the most appropriate osteotomy.

Return-to-Sport Review for Current Cartilage Treatments.

The return to play outcome is an important measure for orthopaedic sports medicine treatments. This variable is especially important when discussing cartilage treatments because there are many different cartilage options available to athletes with articular injuries and this population is particularly interested in the ability to return to activities. Although many outcome variables are considered in any surgical procedure, the return-to-sport variable is focused on an active population and can be tailored to that patient's sport-specific goals. In this article, we will review some of the most recent and up-to-date articles describing return-to-sport outcomes for various knee cartilage treatments. This article will focus on the most common current knee cartilage treatments including microfracture, autologous chondrocyte implantation, osteochondral autograft transplant, and osteochondral allograft transplantation.

Limb occlusion pressure for blood flow restricted exercise: Variability and relations with participant characteristics.

OBJECTIVE: Assess lower-extremity blood flow restricted exercise (BFR) limb occlusion pressure (LOP) variability and identify related intrinsic characteristics using a portable Delphi BFR system. DESIGN: Repeated measures. SETTING: Laboratory. PARTICIPANTS: Forty-two healthy males (n = 25) and females (n = 17) (25.8 ± 5.2 y, 1.76 ±0 .09 m, 78.9 ± 14.9 kg) completed two visits. Brachial artery blood pressure, thigh circumferences (TC), and LOP were measured supine. MAIN OUTCOME MEASURES: Linear mixed-effects models (LMM) and generalizability theory were used to evaluate LOP between legs and days, determine intrinsic characteristic relations, and assess random variance components. RESULTS: LOP was not different between legs (p = .730) or days (p = .916; grand mean = 183.7 mmHg [178.4, 189.1]). LOP varied significantly between participants (p = .011, standard error = 47.3 mmHg). 47% of LOP variance was between participants, 18% and 6% was within participants between days and legs, respectively, and 28% was associated with random error. The relative error variance was 14.4 mmHg. Pulse pressure (PP) (p = .005) and TC (p = .040) were positively associated with LOP. A LMM including PP and TC predicted LOP with a mean absolute difference of 11.1 mmHg [9.7, 12.6] compared to measured LOP. CONCLUSIONS: The relative error variance suggests that clinicians should measure LOP consistently for each patient to ensure BFR safety and effectiveness.

Is Plain Anterior-Posterior Radiograph of the Pelvis Adequate for Assessment of Radiographic Implant Migration Evaluation in Total Hip Arthroplasty?

Introduction: A commonly utilized method of measuring femoral stem migration in total hip arthroplasty (THA) on plain anteroposterior (AP) pelvis radiograph with referenced image magnification has not been rigorously evaluated. This study aims to validate the reproducibility of the methods used in this technique. Methods: A retrospective study of the standardized AP pelvis radiographs of patients who had undergone THA utilizing a Corail® femoral stem was performed from June 2012 through December 2017. Radiological evaluation (head diameter, stem length, and stem seating length) were undertaken at three clinical follow-up times. Each radiographic measurement of each radiograph was repeated five times. Outcomes investigated included inter- and intra-radiograph reproducibility evaluation and radiographic image magnification. The stem length error and stem subsidence were also evaluated. Results: Two hundred THA patients met the inclusion/ exclusion criteria. The intra-radiograph reproducibility of the stem length and head diameter measurements have at least "good" reproducibility with repeated measurements falling within 0.5 mm for both measurements. The reliability for femoral stem seating length measurements has "questionable/poor" reproducibility. The inter-radiograph reproducibility was, however, substantially lower. High level of unreliable measurements with values less than 0.0 mm for both femoral stem length errors (55%) and femoral stem subsidence (32%) measurements. Less than 45% accuracy (femoral stem length error: 33%; femoral stem subsidence: 44%) to within 3 mm error. Conclusions: This study demonstrates that the assessment of radiographic implant migration after THA made on a sequence of plain AP pelvis radiograph have poor reproducibility.Level of Evidence: III.

Biomechanical Evaluation of the Accuracy in Radiographic Assessment of Femoral Component Migration Measurement after Total Hip Arthroplasty.

INTRODUCTION: Implant subsidence is one criteria utilized to monitor for prosthesis loosening after total hip arthroplasty (THA) with initial implant subsidence assessment often done utilizing plain radiographs. The specific aim of this study was to identify the most reliable references when using plain radiographs to establish an image magnification with the goals being easy to use, inexpensive, reliable, and accurate. METHODS: Two femoral stem implants (stem lengths: 127 mm, 207 mm) were utilized to simulate hemiarthroplasty of the hip with composite femurs. Different combinations of femoral stem distances from the radiographic film (ODD), source-detector differences (SDD), hip rotation, and hip flexion were elected. Standardized anterior-posterior pelvis for each parameter combination setup were taken. Radiographic measurements (head diameter, stem length, stem seating length) were undertaken five times by three examiners. Radiographic image magnification factors were generated from two references (head diameter and stem length). Radiograph measurement reproducibility and stem seating length errors using these magnification factors were evaluated. RESULTS: High level of repeated measurements reliability was found for head diameter (99 ± 0%) and stem length (90 ± 7%) measurements, whereas seating length measurements were less reliable (76 ± 6%). Stem length error using the femoral head magnification factor yielded 11% accuracy. Stem seating length error using both magnification factors were not reliable (< 7% accuracy). All parameters, except SDD, showed significant effect on calibrated measurement error. CONCLUSION: Current methods of assessing the implant subsidence after THA are inaccurate and unreliable. Clinicians should recognize these limitations and be cautious when diagnosing implant stability using plain radiographs alone.

Effect of Jump Direction and External Load on Single-Legged Jump-Landing Biomechanics.

External load may increase an individual's risk of non-contact anterior cruciate ligament (ACL) injury during single-legged jump-landing (SLJL). This study evaluated the effects of jump direction and external load on hip and knee joint motion and time to stabilization (TTS) during SLJL. Seventeen active males (n = 8) and females (22.2 ± 3.0 y, 1.75 ± 0.08 m, 73.4 ± 12.0 kg) participated in this randomized, crossover designed study. Single-legged jump-landings performed in two conditions, including without external load (BW) and with a torso-worn weight vest equal to 10% of the participant's body weight (BW+10%), from backward, forward, medial, and lateral SLJL directions. Two-way repeated measures ANOVA did not identify any significant interactions (P > .01, η2: < .001 - .037), but some main effects for condition with small effect sizes were identified (P < .01, η2: .009 - .039). Several main effects for SLJL direction were identified with larger effect sizes (P < .01, η2: .010 - .574). This suggests SLJL direction may challenge different components of SLJL biomechanics, and that recreationally active, college-aged individuals may possess effective compensatory mechanisms that can mitigate the effect of BW+10%.

Independent Suture Tape Reinforcement of Tripled Smaller-Diameter and Quadrupled Grafts for Anterior Cruciate Ligament Reconstruction With Tibial Screw Fixation: A Biomechanical Full Construct Model.

PURPOSE: To compare the effect of independent suture tape reinforcement on the dynamic elongation and stiffness behavior as well as ultimate strength of tripled smaller-diameter and quadrupled soft-tissue grafts for anterior cruciate ligament reconstruction (ACLR) with tibial screw fixation in a biomechanical in vitro study. METHODS: Tripled smaller-diameter (8 mm) and quadrupled (9 mm) bovine tendon grafts with and without suture tape reinforcement (n = 8 in each group) were tested using femoral suspensory and tibial interference screw fixation. The suture tape was femoral sided and fixed independent from the graft by passing it through the suspensory button and securing the 2 open tibial strands with a secondary interference screw. Dynamic testing was performed in position and force control at 250 N and 400 N, followed by pull to failure with the mode of failure noted. Dynamic elongation, stiffness, and ultimate strength were analyzed. RESULTS: Tripled constructs showed a significantly worse structural performance than quadrupled constructs at higher loads. Reinforcement of tripled and quadrupled grafts substantially decreased total elongation by 56% (4.54 ± 0.75 mm vs 2.01 ± 0.50 mm, P < .001) and 39% (3.25 ± 0.49 mm vs 1.98 ± 0.51 mm, P < .001), respectively, by significantly increasing dynamic stiffness. No statistical significance was found between the reinforced groups. Failure loads of reinforced tripled (1,074 ± 148 N vs 829 ± 100 N, P = .003) and quadrupled (1,125 ± 157 N vs 939 ± 76 N, P = .023) grafts were also significantly improved. CONCLUSIONS: Independent reinforcement of soft-tissue grafts with suture tape strengthened the performance especially of tripled smaller-diameter grafts for ACLR with tibial screw fixation by significantly improving dynamic elongation at increased stiffness and ultimate strength. Quadrupled reinforced grafts showed no over-constraining and structurally behaved similarly to tripled grafts with reinforcement. CLINICAL RELEVANCE: Independent reinforcement for ACLR may provide an option for protecting autografts or allografts against irreversible lengthening during the maturation and remodeling phases of healing.

Comparing the Influence of Different Overhand/Underhand Stacking Combinations of Reversing Half-Hitches on Alternating Posts on Arthroscopic Knot Security.

INTRODUCTION: Previous literature demonstrated the importance of stacking at least three reversing half-hitches on alternating posts (RHAPs) following arthroscopic knot placement. However, RHAPs construction involves looping the suture in either an "overhand" or an "underhand" manner as it relates to the post, which may affect knot security. This study investigated the presently unidentified influence of different stacking combinations of three RHAPs and suture material on arthroscopic knot security. METHODS: Four different RHAPs stacking combinations were tied with three different suture materials. Ten knots of each configuration were tied using each suture material, resulting in 120 evaluated knots. A single load-to-failure test was performed. The mode of failure and mean ultimate clinical failure load were recorded. RESULTS: Different overhand/underhand stacking combinations of three RHAPs had a statistically significant effect on arthroscopic knot strength and security; however, all combinations surpassed the minimum ultimate clinical failure threshold. Knots constructed with either Force Fiber® or braided fishing line had mean ultimate clinical failure loads of greater than 200 N and most commonly failed due to suture material breakage (100%, 60 - 80% respectively). Conversely, FiberWire® demonstrated lower mean ultimate clinical failure loads and had a higher incidence of elongated but intact failure (60 - 90%). CONCLUSION: Different overhand/underhand stacking combinations of three RHAPs yielded an arthroscopic knot capable of secure tissue fixation. A significant effect was observed for suture materials on the knot strength. This study increases our understanding of suitable RHAPs construction following arthroscopic knot placement that can lead to improving the ultimate clinical failure loads of constructed arthroscopic knots observed between orthopedic surgeons.

A Biomechanical Comparison of Varying Base Knot Configurations with Different Overhand/Underhand Combinations of Reversing Half-Hitches on Alternating Posts After Basic Instructional Training.

Background: Constructing a durable arthroscopic knot is critical for secure tissue fixation. The effect of various arthroscopic base knot configurations paired with various overhand/underhand stacking combinations of three reversing half-hitches on alternating posts (RHAPs) on knot strength and integrity remains unanswered. Methods: Three common base knots (Surgeon's, Weston and, Tennessee Slider) followed by different overhand/underhand stacking combinations of three RHAPs were evaluated. Ten knots of each combination were tied by four subjects with varying levels of experience, resulting in the analysis of 480 total knots. A single load-to-failure test was performed to evaluate knot strength and integrity. The ultimate clinical failure load and mode of failure were recorded. Results: All knots created surpassed the estimated minimum required load per suture. There was, however, statistically large inter-subject variability for each base knot configuration. The Surgeon's base knot was found to vary the least in knot strength, while the Tennessee base knot was found to vary the most. Knot security was mostly influenced by the base knot configuration than the different overhand/underhand RHAP stacking combinations. Knot slippage failure mode was higher with knots tied with the Weston base knot compared to the other two configurations. Conclusions: Arthroscopic base knot configurations paired with different overhand/underhand stacking combinations of RHAPs yielded knot capable of secure tissue fixation. A short instructional training period appears to be sufficient for inexperienced individuals to learn easier base knot configurations, more challenging and complicated knots, however, may require training in a more gradual fashion. Clinical Relevance: The findings of this study provide information that the importance of hands-on experience for inexperienced individuals, such as residents, in performing arthroscopic knot tying, and that can lead to improving the securely constructed arthroscopic knots, which increase positive outcomes related to strengthened soft tissue to bone fixation of post-operative patients.Level of Evidence: V.

Blood Flow Restriction Resistance Exercise as a Rehabilitation Modality Following Orthopaedic Surgery: A Review of Venous Thromboembolism Risk.

Synopsis Restoration of skeletal muscle mass and strength is critical to successful outcomes following orthopaedic surgery. Blood flow restriction (BFR) resistance exercise has emerged as a promising means of augmenting traditional low-intensity physical rehabilitation exercise and has yielded successful outcomes in a wide range of applications. Though BFR is well tolerated and safe for most individuals, patients who have undergone orthopaedic surgery may be an exception, due to their heightened risk for venous thromboembolism (VTE). While the pathogenesis of VTE is multifactorial and specific to the individual, it is commonly described as a combination of blood stasis, endothelial injury, and alterations in the constituents of the blood leading to hypercoagulability. The collective literature suggests that, given the pathogenic mechanisms of VTE, limited use of a wide, partially occluding cuff during resistance exercise should be low risk, and the likelihood that BFR would directly cause a VTE event is remote. Alternatively, it is plausible that BFR may enhance blood flow and promote fibrinolysis. Of greater concern is the individual with pre-existing asymptomatic VTE, which could be dislodged during BFR. However, it is unknown whether the direct risk associated with BFR is greater than the risk accompanying traditional exercise alone. Presently, there are no universally agreed-upon standards indicating which postsurgical orthopaedic patients may perform BFR safely. While excluding all these patients from BFR may be overly cautious, clinicians need to thoroughly screen for VTE signs and symptoms, be cognizant of each patient's risk factors, and use proper equipment and prescription methods prior to initiating BFR. J Orthop Sports Phys Ther 2019;49(1):17-27. Epub 12 Sep 2018. doi:10.2519/jospt.2019.8375.

Characterization and Correction of Symptomatic Hip Impingement in American Football Linemen.

BACKGROUND: Femoroacetabular impingement (FAI) morphology can lead to range-of-motion deficits in football players. It is therefore important for physicians treating these players to be aware of the location and implications of FAI morphology. PURPOSE/QUESTIONS: We sought to characterize the radiographic deformity and dynamic impingement observed in a consecutive series of American football linemen with symptomatic, mechanical hip pain who underwent surgical treatment for FAI and to use software analysis to identify the location of impingement and terminal range of motion and the effects of simulated correction. METHODS: A retrospective analysis was conducted of 17 hips in 13 football linemen who underwent arthroscopic correction for symptomatic FAI. Computed tomography (CT) scans were used to generate preoperative three-dimensional models of the hips. Femoral and acetabular measurements, maximum hip flexion, abduction, internal rotation at 90° flexion (IR90), and flexion/adduction/internal rotation (FADIR) were determined, and areas of bony collision were defined. Simulated femoral correction was performed and motion analysis was repeated. RESULTS: Mean femoral version was 13.1° (range, 0 to 26°), while mean femoral neck-shaft angle was 132.1° (range, 123 to 145°). Mean maximum alpha angle on the radial reformatted CT was 69.2° (range, 48 to 95°) and was located at the 12:45 clock-face position (range, 11:30 to 2:15). Mean acetabular version values at 1:30 and 3:00 were 1.1° (range, - 11 to 11°) and 12.7° (range, 2 to 20°), respectively. Fifty-three percent of hips showed a "crossover" sign. Mean lateral center-edge angle was 31.7° (range, 25 to 44°). CT-derived motion analysis demonstrated a mean preoperative flexion of 108.2° (range, 73 to 127°), IR90 of 20.5° (range, 0 to 52°), and FADIR of 12.3° (range, 0 to 39°). Simulated correction resulted in significant improvements in flexion (6.6°), IR90 (11.3°), and FADIR (10.6°). CONCLUSIONS: While cephalad retroversion was observed in approximately half of the hips, a significant cam deformity was seen maximally at 12:45, a more posterior cam location than that of the general population. Managing this pathology required obtaining preoperative and intraoperative images to characterize lesions and allow for their complete correction. With complete correction of the deformity, simulated range of motion demonstrated significant improvement in flexion, IR90, and FADIR maneuvers.

Arthroscopic Management and Radiographic Interpretation of an Everted Bony Bankart Lesion.

Soft tissue injuries are prevalent after traumatic anterior shoulder dislocation. However, bony fractures, often referred to as bony Bankart injuries, are less common. The authors describe the case of a 16-year-old male who displayed a bony Bankart with a unique, everted presentation. The patient presented with left shoulder pain, restricted range of motion, and crepitus. Two weeks prior to physical examination, he sustained a traumatic anterior glenohumeral dislocation after a bicycle accident, which reduced spontaneously. Plain film imaging revealed a bony fragment off the anterior glenoid. Upon critical examination of magnetic resonance imaging axial cuts, the bony fragment was found to be flipped. Intraoperatively, this orientation was confirmed. The fragment was reduced and stabilized in an anatomic position using a double row technique with the capsule then advanced over the top of the fragment using three additional anchors. Imaging four months postoperatively revealed an anatomical reduction of the fragment. To the authors' knowledge, this is the first reported case of bony fragment eversion following traumatic anterior shoulder dislocation. Although the incidence of everted bony fragments following traumatic dislocation is unknown, such a situation presents unique challenges to the orthopedic surgeon. The authors discuss potential eversion mechanisms, fragment identification by imaging, surgical indications, and operative techniques.

Intraoperative Preconditioning of Fixed and Adjustable Loop Suspensory Anterior Cruciate Ligament Reconstruction With Tibial Screw Fixation-An In Vitro Biomechanical Evaluation Using a Porcine Model.

PURPOSE: To evaluate the effect of preconditioning according to intraoperative workflow on initial tension and elongation behavior for femoral adjustable loop devices (ALDs) and closed loop devices (CLDs) in suspensory anterior cruciate ligament reconstruction (ACLR) with tibial screw fixation in a biomechanical in vitro study. METHODS: Three ACLR groups with tibial screw fixation were biomechanically tested in a full-construct setup using porcine tibias. Groups (n = 8 per group) varied by femoral fixation method and consisted of a CLD (group 3) and ALD fixation with (group 2) and without simulated intraoperative preconditioning (group 1). The change in tension after screw insertion and the displacement to restore the initial loading situation were measured. Grafts underwent dynamic cycling (1,000 cycles at 0.75 Hz) using both a position and a force control mode. RESULTS: Data are presented as mean [standard deviation]. Placement of an interference screw induced a graft tension loss of 62% (49.4 [0.4] N vs 19.0 [10.0] N, P < .001) by introducing a laxity of 0.53 [0.26] mm. Intraoperative preconditioning led to a higher initial load level (228.3 [19.8] N) compared with unconditioned ALD (156.1 [25.5] N, P < .001) and CLD groups (156.6 [12.8] N, P < .001) with less force decrease over position-controlled cyclic loading. Furthermore, initial (-0.22 [0.16] mm) and dynamic elongation (0.88 [0.23] mm) were reduced compared with the unconditioned ALD (0.65 [0.35] mm, P < .001; and 1.56 [0.19] mm, P < .001) and CLD groups (0.16 [0.26] mm, P < .001; and 1.64 [0.24] mm, P < .001). CONCLUSIONS: ACLR with femoral ALD fixation and intraoperative preconditioning allows for restoration of time-zero screw-imparted slack and leads to significantly reduced cyclic elongation in accordance with native ACL function. Both ALD and CLD control groups behaved similarly, with total elongation less than 3 mm including time-zero slack. CLINICAL RELEVANCE: Although the clinical relevance of time-zero graft tension loss is uncertain, the use of an ALD in concert with tibial screw fixation may be favorable to allow for tension optimization.