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Purpose A large percentage of anterior cruciate ligament (ACL) surgical reconstructions experience sub-optimal outcomes within 2 years. A potential factor contributing to poor outcomes is an incomplete understanding of micro-level, regional ACL biomechanics. This research aimed to demonstrate a minimally invasive method that uses micro-CT imaging to quantify regional ACL strains under clinically relevant joint loading. Methods A pattern of 0.8 mm diameter zirconium dioxide beads were arthroscopically inserted into four regions of the ACL of four cadaveric knee specimens (mean [SD] age = 59 [9] years). A custom micro-CT compatible joint motion simulator then applied clinically relevant joint loading conditions, while an image was acquired at each condition. From the resulting images, strains within each region were calculated using the centroid coordinates of each tissue-embedded bead. Strain repeatability was assessed using the mean intra-specimen standard deviation across repeated load applications. A one-way repeated measures ANOVA (α = 0.05) was used to determine regional strain variations. Results The mean intra-specimen standard deviation across repeated load application was ±0.003 strain for all specimens. No statistically significant differences were found between tissue regions, although medium and large effect sizes (0.095–0.450) suggest that these differences may be clinically relevant. Conclusions The method presented here demonstrates a minimally invasive measurement of regional ACL strain under clinically relevant joint loads using micro-CT imaging. The strain measurements demonstrated excellent reliability across the five repeated load applications and suggest a non-homogenous distribution of strain through the ACL.

The purpose of this work was to assess the resolution to which micro-CT and intra-operative CT systems can quantify distances between radiopaque fiducial markers. Twenty-two markers were cast in a silicone phantom, then imaged at ten random rotations and translations within the field of view of a micro-CT and an intraoperative CT. A bounding box method and a mask-based weighted binary method were used to calculate the location of all markers in an image, then the Euclidian distance between neighbouring marker coordinates was calculated. The standard deviation in the inter-marker distance measurements from each of the marker position methods across the ten repeated trials was calculated for each marker identification method to provide a measure of the precision of the strain measurement with each scanner. The imaging systems measured 3D distances between markers to within 0.007 mm and 0.028 mm in the micro-CT and intra-operative CT, respectively, using the bounding box method, and to within 0.011 mm and 0.040 mm in the micro-CT and intra-operative systems, respectively, using the weighted-mask method. The bounding box method was found to be the most precise and is highly promising for applications in high resolution regional soft-tissue strain measurements.

Background: Several techniques for hip capsular reconstruction have been described to address gross instability or microinstability due to capsular deficiency. However, objective biomechanical data to support their use are lacking. Purpose: To compare the kinematic effect of 2 capsular reconstruction techniques (iliotibial band [ITB] graft and Achilles tendon graft). Kinematic effect encompassed rotational range of motion (ROM) as well as joint translation in the coronal, sagittal, and axial planes. Study Design: Controlled laboratory study. Methods: 8 paired, fresh-frozen hemi-pelvises (16 hips) were tested on a custom-designed joint motion simulator in the intact state and after capsulectomy. Pairs were randomly allocated to either ITB or Achilles reconstruction and retested. Testing was performed at 0°, 45°, and 90° of flexion. Internal-external rotation (IR-ER) torques and abduction-adduction torques of 3 N·m were applied to the femur via a load cell at each position, and rotational ROM and joint translation in the coronal, sagittal, and axial planes were recorded. Results: At 45° and 90°, there was a significant effect of the condition of the hip on the total IR-ER ( P = .004, effect size [ES] = 0.305; and P < .001, ES = 0.497; respectively). At 45°, mean ± SD total rotation was significantly greater for the capsulectomy (59.7°± 15.9°) state compared with intact (53.3°± 13.2°; P = .007). At 90°, reconstruction significantly decreased total rotation to 49.0°± 18.9° compared with a mean total rotation of 52.8°± 18.7° after capsulectomy ( P = .02). No difference was seen in the total abduction-adduction of the hip between conditions. Comparisons of the 2 different reconstruction techniques showed no significant differences in total IR-ER or abduction-adduction ROM or joint translation in the coronal, sagittal, or axial planes. For translation, at both 0° and 45° there was a statistically significant effect of the condition on the medial-lateral translation ( P = .033; ES = 0.204). Reconstruction, independent of technique, was successful in significantly decreasing ( P = .030; P = .014) the mean medial-lateral translation at 0° and 45° of hip flexion from 5.2 ± 3.8 mm and 5.6 ± 4.0 mm to 2.8 ± 1.9 mm and 3.9 ± 3.2 mm, respectively. Conclusion: The integrity of the native hip capsule played a significant role in rotational stability, where capsulectomy significantly increased rotational ROM. Both ITB and Achilles reconstruction techniques restored normal rotational ROM of the hip at 90° of flexion as well as coronal plane stability at 0° and 45° of hip flexion. No differences were seen between ITB and Achilles reconstruction techniques. Clinical Relevance: Both capsular reconstruction techniques provide comparable joint kinematics, restoring rotation and translation to normal values with the exception of rotational ROM at 45°, which remained significantly greater than the intact state. The most significant results were the rotational stability at 90° of hip flexion and coronal plane stability at 0° and 45° of hip flexion, which were significantly improved compared with the capsulectomy state.

© 2020 Arthroscopy Association of North America Purpose: To compare the biomechanical differences between quadriceps tendon (QT) repair with high-strength suture (HSS) versus suture tape (ST) with varying number of suture passes. Methods: In total, 28 fresh-frozen QTs were randomized into 2 groups: (1) HSS; or (2) ST; specimens were then further randomized into subgroups of either 4 or 6 suture passes. Specimens were secured within a materials testing system and a 150-N preload was applied for 10 seconds followed by a cyclic loading protocol between 50 N and 250 N for 1000 cycles. Video was used to follow tracking markers used to calculate the magnitude of tendon displacement. Two-way univariate analysis of variance was used to determine the effect of suture type and passes on the displacement after preloading and mixed repeated-measures analysis of variance was used to determine the effect of suture type and passes on displacement following cyclic loading. Results: There were large increases in displacement following the preload across all conditions (7.82 ± 3.64 mm), with no statistically significant differences between groups. There was a significant difference in the mean (± standard deviation) displacement between the ST (5.24 ± 2.82 mm) and HSS (7.93 ± 2.91 mm) starting at 200 cycles, which became more pronounced with successive testing out to 1000 cycles (P = .021). There were no significant difference with respect to the number of suture or tape passes. Conclusions: Following preloading at 150 N, significant displacement occurred in both QT repair groups. ST demonstrated significantly less displacement than HSS under cyclic loading and had greater ultimate failure loads. Clinical Relevance: When performing QT repair, emphasis should be placed on appropriate pretensioning of sutures to at least 150 N before knot-tying. In addition, where available, ST should be used over HSS to reduce further cyclic elongation and improve ultimate failure loads.

Background: Muscle activations (MA) during maximum voluntary contractions (MVC) are commonly utilized to normalize muscle contributions. Isometric MVC protocols may not activate muscles to the same extent as during dynamic activities, such as falls on outstretched hands (FOOSH), that can occur during sport or recreational activities. Objective: The purpose of this study was to compare the peak MA of upper extremity muscles during isometric and dynamic MVC protocols. Methods: Twenty-four (12 M, 12 F) university-aged participants executed wrist and elbow flexion and extension actions during five-second MVC protocols targeting six upper extremity muscles (three flexors and three extensors). Each protocol [isometric (ISO); dynamic (eccentric (ECC), concentric (CON), elastic band (ELAS), un-resisted (UNRES)] consisted of three contractions (with one-minute rest periods between) during two sessions separated by one week. Muscle activation levels were collected using standard electromyography (EMG) preparations, electrode placements and equipment reported previously. Results: Overall, the ECC and CON dynamic protocols consistently elicited higher peak muscle activation levels than the ISO protocol for both males and females during both sessions. Over 95% of the CON trials resulted in mean and peak muscle activation ratios greater than ISO, with 56.3% being significantly greater than ISO (p < 0.05). Conclusion: Higher activation levels can be elicited in upper extremity muscles when resistance is applied dynamically through a full range of motion during MVC protocols.

© The Author(s) 2019. Background: Distal radius fracture reduction by internal fixation is most commonly achieved using volar locking plates (VLPs). Many standard VLP designs make little point contact with radius anatomy, and most postsurgical complications following fixation are attributed to poor implant fit. Sex differences may require consideration in implant design, as females more commonly require VLP removal. Therefore, the purpose of this research was to determine whether the relationships between measures of radius shape are proportional between the sexes. Methods: Three-dimensional radius bone geometries were created from 40 male and 34 female (mean age = 72.04 years) forearm computed tomographic scans in Mimics (Materialise NV, Leuven, Belgium). Eleven measures of radius shape were collected from each scan. Principal components analysis was performed on these measures to determine which shape variables account for the greatest differences in radius shape among individuals and between the sexes. Results: Principal component scores representing isometric radius size separated the sexes. Six anthropometric measures significantly correlated with isometric radius size for all specimens, whereas 3 and 1 measures significantly correlated with isometric radius size in males and females, respectively. Conclusions: Anthropometrics of male and female radii vary by different proportions. Using anthropometrics from both sexes to create a single implant system may not result in optimal patient fit for either sex.

Background Hip capsulotomies, performed routinely during hip arthroscopy, can contribute to adverse joint kinematics. Direct repair is not always feasible. Therefore, the aim of this study was to evaluate the biomechanics of a conventional all-suture repair versus a hybrid suture and anchor-based capsular repair. Methods Nine paired (n = 18) hips were tested on a joint-motion simulator, utilizing optical trackers to capture kinematic data. Pairs were randomly allocated to capsular repair type and tested as (1) intact, (2) after T-capsulotomy, and (3) repair each at 0°, 45°, and 90° flexion. Internal and external rotation torques and abduction/adduction torques of 3 N·m were applied and rotational range of motion and joint translations recorded. Findings At 0°, following repair there were no significant differences in joint rotation or translations between repairs (p > 0.134). At 45°, both repair types restored motion to near intact values, with no significant differences between groups. Similarly, there were no significant differences in joint translations between repairs. At 90°, both types of capsular repair failed to restore rotational range of motion, with persistent increases in motion (47.0 ± 16.7°) compared to the intact condition (44.1 ± 15.8°, p = 0.006); however, there were no significant differences between repair groups. There were no significant differences in joint translations between repairs. Interpretation Use of a hybrid repair produced comparable joint rotation and translation under all testing conditions as an all-suture repair. As such, this technique represents a viable option for capsular repair where proximal capsular tissue is deficient.

© 2020, Biomedical Engineering Society. The characterization of ligamentous soft tissue properties is limited by a lack of measurement methods capable of minimally-invasively quantifying regional strain. Previous implementations of radiographic imaging and tissue-embedded radiopaque markers demonstrated promising regional strain measurements, but found error associated with non-repeatable bead positions within the tissue after load application. No study has investigated the effects of cyclic loading on the strains measured within the tissue. The purpose of this study was to quantify the effect of joint loading on strain measurement using radiopaque markers and micro-computed tomography imaging. Six cadaveric porcine femur-anterior cruciate ligament-tibia complexes were instrumented with small diameter (0.8 mm) zirconium dioxide marker beads. The compound was imaged at 10 N then at 100 N of anterior force using micro-computed tomography. The bead positions in the images were used to calculate tissue strain between the 10 and 100 N anterior joint load conditions. Up to 100 intermediate joint cycles were applied, then images were acquired again at 10 and 100 N anterior force. No statistically significant difference was found between the strains measured before and after intermediate cycling (p > 0.05). This indicates that tissue loading did not introduce statistically significant changes to strains measured in tissue tested following this methodology.

© 2020, European Society of Sports Traumatology, Knee Surgery, Arthroscopy (ESSKA). Purpose: To noninvasively characterize the ligament strain in the hip capsule using a novel CT-based imaging technique. Methods: The superior iliofemoral ligament (SIFL), inferior iliofemoral ligament (IIFL), ischiofemoral ligament (IFL) and pubofemoral ligament (PFL) were identified and beaded in seven cadavers. Specimens were mounted on a joint motion simulator within an O-arm CT scanner in − 15°, 0°, 30°, 60°, and 90° of flexion. 3 Nm of internal rotation (IR) and external rotation (ER) were applied and CT scans obtained. Strains were calculated by comparing bead separation in loaded and unloaded conditions. Repeated-measures ANOVA was used to evaluate differences in strain within ligaments between hip positions. Results: For the SIFL, strain significantly decreased in IR at 30° (p = 0.045) and 60° (p = 0.043) versus 0°. For ER, there were no significant position-specific changes in strain (n.s.). For the IIFL, strain decreased in IR and increased in ER with no significant position-specific differences. For the IFL, strain increased with IR and decreased with ER with no significant position-specific differences. Finally, in the PFL there was a significant flexion angle-by-load interaction (p ' 0.001; ES = 0.566), with peak strains noted at 60˚, however pair-wise comparisons failed to identify significant differences between positions (n.s.). Strain decreased in ER, with no significant position-specific differences. Conclusion: The SIFL and IIFL limit hip external rotation with greater effect in higher flexion angles, while the IFL and PFL limit hip internal rotation. Following hip arthroscopy, consideration should be given to restricting external rotation as traditional capsulotomies cause injury to the SIFL and IIFL.

Background: The ligamentum mucosum is composed of dense regular connective tissue and traverses from the distal femur to the infrapatellar fat pad. While the gross and histologic morphology has been studied, there is currently no evidence concerning the biomechanical properties of the ligamentum mucosum and the potential of anterior knee pain. The purpose of this study was to determine the anatomical, mechanical and histological properties of the ligamentum mucosum. Methods: Dissections were performed on cadaveric knee specimens (N = 18) and histological analysis (n = 6) was performed to define the anatomical characteristics of the ligamentum mucosum using standard hematoxylin and eosin (H&E), Masson's trichrome, and immunohistochemical methods. Biomechanical testing (n = 5) was conducted to determine the tensile properties of the ligamentum mucosum. The peak load at failure, stiffness, and strain were analyzed. Results: Sixty-four percent of the knees had a ligamentum mucosum and the histological analysis confirmed it to be composed of dense regular connective tissue. Small peripheral nerves were identified in the junction between the ligamentum mucosum and the fat pad. The average (SD) peak force of failure, stiffness, and strain were 31.9 N (19.0), 5.1 N/mm (3.59), and 0.83 (0.14), respectively. Conclusions: The tensile strength and stiffness of the ligamentum mucosum is considerably less than the primary stabilizers of the knee joint. Based on these findings, it is improbable that the ligamentum mucosum has a meaningful effect on the kinematics of the extensor mechanism; perturbations of the tissue and the connected infrapatellar fat pad could potentially play a role in the pathogenesis of anterior knee pain. (C) 2018 Elsevier B.V. All rights reserved.

Background: Previous research demonstrated that the attachment of the anterolateral ligament (ALL) to the lateral meniscus is stiffer and stronger in its tibial attachment than its femoral attachment. How this relates to anterolateral knee stability and lateral meniscal function is unknown. Hypothesis/Purpose: The hypothesis was that the ALL acts as a peripheral anchor to the lateral meniscus, aiding in anterolateral rotatory stability, and that the inframeniscal fibers of the ALL will provide greater anterolateral rotatory stability because of their greater tensile properties. The purpose was therefore to compare the difference in kinematics of the anterior cruciate ligament (ACL)–deficient knee between the infra- and suprameniscal ALL-sectioned states. Study Design: Controlled laboratory study. Methods: Eight paired fresh-frozen cadaveric knees were tested in a 5–degree of freedom loading jig under the following loading conditions: 5-N·m internal rotation at 15° incremental angles of flexion and combined 5-N·m internal rotation moment, 10-N·m valgus moment, and 88-N anterior translation force representing a pivot shift test at 0°, 15°, and 30° of flexion. The knees were tested under intact, ACL-deficient, and ACL-/ALL-deficient conditions, with the pairs of knees being randomized to either supra- or inframeniscal ALL sectioning. Resultant joint kinematics and tibiofemoral translations were measured and compared with a 2-way mixed repeated measures analysis of variance. Results: Internal rotation increased by 3° after sectioning of the ACL at 0° of knee flexion ( P = .035). At 45° of knee flexion, internal rotation increased significantly by 2° between the ACL-deficient and the ACL-/ALL-deficient conditions ( P = .049). Secondary kinematics of valgus and anterior translation were observed in response to the 5-N·m load after ACL and ALL sectioning. Analysis of the pivot shift showed increases in tibiofemoral translation after sectioning of the ACL, with further translations after sectioning of the ALL. No differences were observed between supra- and inframeniscal ALL sectioning under any of the loading conditions. Conclusion: An injury to the ALL, coexisting with ACL deficiency, results in only minor increases in knee joint patholaxity. No differences in pivot-shift kinematics or tibiofemoral rotations were observed between the supra- and inframeniscal sectioning of the ALL in the ACL-deficient knee Clinical Relevance: Tears of the midbody and/or posterior root attachment of the lateral meniscus are often observed at the time of ACL reconstruction. Increased anterolateral rotatory laxity has been observed in both lateral meniscus– and ALL-deficient states in combination with an ACL injury. While no significant functional relationship was found between the ALL and lateral meniscus, ALL sectioning did result in increased knee joint patholaxity, as demonstrated by composite tibiofemoral rotations.

IntroductionThe direct anterior approach for total hip replacements has reported advantages of improved early function and muscle preservation. In an effort to improve healing and cosmesis, a change in the orientation of the incision has been proposed. Traditionally, the skin incision is in-line with the tensor fasciae latae muscle belly. The bikini incision is orthogonal to this orientation. The hypothesis was that muscle damage would be increased by using the bikini incision.MethodsA traditional or bikini incision was performed on 18 cadaveric hips. On each of the 9 specimens, the traditional incision was performed on 1 side, and a bikini incision on the contralateral hip, with an even distribution of right or left side. Blinded anatomists performed the hip dissections, and assessed for muscle damage as well as for damage to the lateral femoral cutaneous nerve.ResultsNo difference in muscle damage was identified in the tensor fasciae latae between muscle groups. Muscle damage was very minimal to the gluteus medius and minimus. Damage to the lateral femoral cutaneous nerve occurred equally for both the bikini and traditional skin incisions.ConclusionsThe bikini incision for the direct anterior approach to the hip can be performed safely, with no increase in muscle damage or damage to the lateral femoral cutaneous nerve compared to the traditional incision.

© 2019 American Society for Surgery of the Hand Purpose: Anthropometric assessment of bony structures in the body is important for preoperative computer-aided surgery, implant design, finite element modeling, and biomechanical studies investigating joint structure and function. The use of the contralateral limb in surgery and clinical practice relies on the assumption that the right and left limbs of an individual are symmetric. Therefore, the purpose of this study was to quantify the bilateral symmetry of the bony structures of the distal radius using 3-dimensional (3D) computed tomography. Methods: We collected computed tomography images of 37 paired, fresh-frozen, healthy cadaveric male upper limbs (aged 75.4 ± 8.3 years). Three-dimensional reconstructed models were created using semiautomatic segmentation. Using the 3D models, we measured 3D radial inclination, 3D volar tilt, 3D radial height, medial volar cortical angle, middle volar cortical angle, and lateral volar cortical angle and compared them between sides. Results: There were no statistically significant differences measured between right and left distal radius in 37 paired wrists. Mean radial height was 12.81 mm (SD, 1.74 mm) on the left and 12.88 mm (SD, 1.72 mm) on the right. Mean volar tilt was 10.74° (SD, 3.74°) and 10.77° (SD, 3.19°) and radial inclination was 24.05° (SD, 2.63°) and 24.18° (SD, 3.41°) on the left and right, respectively. Mean volar cortical angle across the radius was 140.9° (SD, 7.9°) on the left and 140.1° (SD, 7.9°) on the right. Conclusions: Direct bilateral comparison of the distal radius and wrist joints is useful to predict normal anatomy of the injured radius, because bilateral similarities exist. Clinical relevance: This article provides a comprehensive list of measurements of the distal radius compared bilaterally using a 3D model. From this study, we found that the contralateral radius can be used as a benchmark with which to compare fracture reduction and to manage malunions during the preoperative planning of corrective osteotomies. It can also be used to define normal anatomy.

When used in combination with decompression, spinal fusion is a successful procedure for treating patients with spinal stenosis and degenerative spondylolisthesis. While a number of auxiliary devices have been proposed to enhance the fixation of the screw within the pedicle and vertebral body, there is conflicting information regarding the efficacy of their use. Therefore, the aim of this study was to determine the ability of a novel expandable pedicle screw to improve the fixation of the pedicle screw within the pedicle and vertebral body. A three-dimensional (3D) printed, screw sleeve was designed that expanded within the pedicle and vertebral body when a standard pedicle screw was inserted into it. The left and right pedicle of ten (N = 10) cadaveric lumbar spine specimens (L3–L5) were randomly assigned to be instrumented with either a pedicle screw and the sleeve or a pedicle screw only. Following instrumentation, the screws were exposed to tensile load at 5 mm/min until failure. The failure force, failure deformation, and area under the force–deformation curve were determined and compared between screw conditions. There were no significant differences between the screws and sleeve, and the screw only conditions for the failure force (p = 0.24), failure displacement (p = 0.10), and area under the curve (p = 0.38). While the novel screw sleeve presented here performed as well as a screw without a sleeve, it was better than other screw augmentation devices reported previously. In addition, it is likely that this device would prove useful as an enhancement to revision.

Background: Although the use of hip arthroscopy continues to increase, capsular management remains a controversial topic. Purpose: To investigate the biomechanical effect of capsulotomy and capsular repair techniques on hip joint kinematics in varying combinations of sagittal and coronal joint positions. Study Design: Controlled laboratory study. Methods: Eight fresh-frozen hemi-pelvises (78.3 ± 6.0 years of age; 4 left, 6 male) were dissected of all overlying soft tissue, with the exception of the hip joint capsule. The femur was potted and attached to a load cell, while the pelvis was secured to a custom-designed fixture allowing static alteration of the flexion-extension arc. Optotrak markers were rigidly attached to the femur and pelvis to track motion of the femoral head with respect to the acetabulum. After specimen preparation, 7 conditions were tested: (1) intact, (2) after portal placement (anterolateral and midanterior), (3) interportal capsulotomy (IPC) (35 mm in length), (4) IPC repair, (5) T-capsulotomy (IPC +15-mm longitudinal incision), (6) partial T-repair (repair of longitudinal incision with IPC left open), (7) full T-repair. All conditions were tested in 15° of extension (–15°), 0°, 30°, 60°, and 90° of flexion. Additionally, all flexion angles were tested in neutral, as well as in specimen-specific maximum abduction and adduction, resulting in 15 testing positions. Internal rotation (IR) and external rotation (ER) moments of 3 N·m were manually applied to the femur via the load cell at each position. Rotational range of motion and joint kinematics were recorded. Results: In the neutral coronal plane, T-capsulotomy significantly increased IR/ER rotational range of motion compared with intact state at −15° (55.96°± 6.11° vs 44.92°± 7.35°, P < .001), while IPC significantly increased rotation compared with the portal state at 0° (60.09°± 6.82° vs 51.68°± 10.35°, P = .004). No statistically significant increases were found in mediolateral joint translation after IPC or T-capsulotomy. Similarly, no statistically significant increases were noted in anteroposterior translation after IPC or T-capsulotomy. Complete capsular repair restored near native joint kinematics, with no significant differences in rotation or translation between any complete capsular repair groups and the intact state, regardless of joint position. Conclusion: Universally, across all conditions, complete capsular repair after interportal or T-capsulotomy restored rotational range of motion and joint translation to values observed in the native joint. Clinical Relevance: Where feasible, complete capsular closure should be performed, especially after T-capsulotomy. However, further clinical evaluation is required to determine whether adverse kinematic parameters of an unrepaired capsule are associated with reduced patient-reported outcomes.

Medial opening wedge high tibial osteotomy (MOWHTO) is a surgical procedure intended to alter the coronal and sagittal plane alignment of the lower limb to primarily relieve the symptoms of osteoarthritis in the medial compartment of the knee. The purpose of this work was to develop and validate a finite element model to simulate the opening of a high tibial osteotomy and determine whether a pilot hole at the cortical hinge reduces the risk of lateral cortical fracture. Fifteen models were reconstructed from CT images of eight cadaveric specimens. The validated models indicated that the addition of the pilot hole increased the stresses and likelihood of a type-I and type-II fractures during the opening of a medial open wedge high tibial osteotomy compared to the no-hole condition.

© 2019, European Society of Sports Traumatology, Knee Surgery, Arthroscopy (ESSKA). Purpose: To determine the effectiveness of a synthetic bone insert on improving medial opening wedge high tibial osteotomy integrity in response to post-surgical cyclical loading. Materials and methods: A medial opening wedge high tibial osteotomy, secured with a compression fixation plate, was performed on 12 cadaveric knee specimens that were randomised to either: (1) a synthetic insert condition (n = 6), in which a 9 mm bio-absorbable wedge was inserted into the gap space; or (2) a plate-only condition (n = 6). Uniaxial strain gauges, placed on the lateral cortex and fixation plate, measured the strain response as the specimens were subjected to a staircase cyclical loading protocol; a sinusoidal waveform between 100 and 800 N was applied and increased by increments of 200 N every 5000 cycles until failure. Peak strains at failure were compared between conditions using a one-tailed independent samples t test. Results: The strains from the fixation plate were significantly different between the insert and plate only conditions (p = 0.02), transitioning from a compressive strain with the wedge (mean [SD] = − 8.6 [− 3.6] µε) to a tensile strain without the wedge (mean [SD] = 12.9 [23] µε). The strains measured at the lateral cortex were also significantly affected by the inclusion of a synthetic bone insert (p = 0.016), increasing from − 55.6 (− 54.3) µε when the insert was utilised to 23.7 (55.7) µε when only the plate was used. Conclusions: The addition of a synthetic insert limited the tensile strains at the plate and lateral cortex, suggesting that this may protect these regions from fracture during prolonged loading.

Background: As our understanding of anterior cruciate ligament (ACL) anatomy has evolved, surgical techniques to better replicate the native anatomy have been developed. It has been proposed that the introduction of a rectangular socket ACL reconstruction to replace a ribbon-shaped ACL has the potential to improve knee kinematics after ACL reconstruction. Purpose: To compare a rectangular femoral tunnel (RFT) with a cylindrical femoral tunnel (CFT) in terms of replicating native ACL strain and knee kinematics in a time-zero biomechanical anatomic ACL reconstruction model using a bone–patellar tendon–bone (BTB) graft. Study Design: Controlled laboratory study. Methods: In total, 16 fresh-frozen, human cadaveric knees were tested in a 5 degrees of freedom, computed tomography–compatible joint motion simulator. Knees were tested with the ACL intact before randomization to RFT or CFT ACL reconstruction using a BTB graft. An anterior translation load and an internal rotation moment were each applied at 0°, 30°, 60°, and 90° of knee flexion. A simulated pivot shift was performed at 0° and 30° of knee flexion. Ligament strain and knee kinematics were assessed using computed tomography facilitated by insertion of zirconium dioxide beads placed within the substance of the native ACL and BTB grafts. Results: For the ACL-intact state, there were no differences between groups in terms of ACL strain or knee kinematics. After ACL reconstruction, there were no differences in ACL graft strain when comparing the RFT and CFT groups. At 60° of knee flexion with anterior translation load, there was significantly reduced strain in the reconstructed state ([mean ±standard deviation] CFT native, 2.82 ± 3.54 vs CFT reconstructed, 0.95 ± 2.69; RFT native, 2.77 ± 1.71 vs RFT reconstructed, 1.40 ± 1.76) independent of the femoral tunnel type. In terms of knee kinematics, there were no differences when comparing the RFT and CFT groups. Both reconstructive techniques were mostly effective in restoring native knee kinematics and ligament strain patterns as compared with the native ACL. Conclusion: In the time-zero biomechanical environment, similar graft strains and knee kinematics were achieved using RFT and CFT BTB ACL reconstructions. Both techniques appeared to be equally effective in restoring kinematics associated with the native ACL state. Clinical Relevance: These data suggest that in terms of knee kinematics and graft strain, there is no benefit in performing the more technically challenging RFT as compared with a CFT BTB ACL reconstruction.

Background The purpose of this study was to determine the gap achieved to the medial and lateral compartments following sectioning and release of the relevant soft tissues in preparation for a total knee arthroplasty. Methods A custom-designed knee tensioner allowed the application of forces to the medial and lateral compartments of 12 cadaveric knee specimens. Loads of 100 N and 200 N were applied to each compartment, and the resulting displacement was measured in the following conditions: (1) All soft tissues intact, (2) an arthrotomy, (3) anterior cruciate ligament (ACL) sectioned, (4) posterior cruciate ligament (PCL) sectioned, and (5) release of the anterior aspect of the deep medial collateral ligament (MCL) fibers. Tensions were applied for all conditions from 90° to 0° of knee flexion in 30° increments. Results No differences were found in medial or lateral displacement after the arthrotomy or releasing the ACL or PCL at either 100 N or 200 N. At the 100 N load application, there was a significant increase in gap width when the anterior portion of the deep MCL was released (7.49 mm) compared to the intact (5.28 mm) and arthrotomy (5.75 mm) conditions. With respect to the 200 N load application, there were statistically significant differences detected between the deep MCL fiber release (11.09 mm) and intact conditions (8.05 mm) and release of the deep MCL and arthrotomy conditions (8.77 mm). Conclusion The medial parapetellar arthrotomy, ACL and PCL sectioning did not result in medial or lateral displacement changes. The release of the anterior fibers of the deep MCL as part of the surgical exposure increased the medial gap magnitude.

© 2019, European Society of Sports Traumatology, Knee Surgery, Arthroscopy (ESSKA). Purpose: Previous studies have implicated the iliotibial band and its deeper capsulo-osseous layer as key restraints against internal rotation. However, the kinematic properties of the capsulo-osseous layer, throughout knee range of motion, are not currently known. Therefore, the purpose of this research was to quantify the length changes of this structure through various degrees of knee flexion. Methods: Ten cadaveric knee specimens were dissected to expose the capsulo-osseous layer of the iliotibial band. Radiopaque beads were embedded, at standardized increments, into the tissue and fluoroscopic images were taken from 0° to 105° of knee flexion in 15° increments. The positions of the beads were identified in each image and the length, width, and area changes of the capsulo-osseous layer were calculated. The data were analyzed as a percent change from 0° and compared across flexion angles using a repeated-measures analysis of variance (α = 0.05). Results: There was a significant increase in the length of the capsulo-osseous layer at flexion angles greater than 30°, with changes occurring primarily at the level of the femoral insertion. Meanwhile, non-homogenous decreases in width and area were found with increasing flexion angle. The distance between the capsulo-osseous layer insertion on the distal femur and proximal tibia significantly increased from 60° to 105°; maximal changes occurred at 105° [9.64 (4.12) %, p = 0.003]. Conclusions: The capsulo-osseous layer of the iliotibial band behaves in a non-isometric fashion and this work suggests that tensioning and fixation should occur between 75° and 105° of flexion, if repair or reconstruction is indicated.

Aim It has been suggested that the use of a pilot-hole may reduce the risk of fracture to the lateral cortex. Therefore the purpose of this study was to determine the effect of a pilot hole on the strains and occurrence of fractures at the lateral cortex during the opening of a high tibial osteotomy (HTO) and post-surgery loading. Materials and Methods A total of 14 cadaveric tibias were randomized to either a pilot hole (n = 7) or a no-hole (n = 7) condition. Lateral cortex strains were measured while the osteotomy was opened 9 mm and secured in place with a locking plate. The tibias were then subjected to an initial 800 N load that increased by 200 N every 5000 cycles, until failure or a maximum load of 2500 N. Results There was no significant difference in the strains on the lateral cortex during HTO opening between the pilot hole and no-hole conditions. Similarly, the lateral cortex and fixation plate strains were not significantly different during cyclic loading between the two conditions. Using a pilot hole did not significantly decrease the strains experienced at the lateral cortex, nor did it reduce the risk of fracture. Conclusions The nonsignificant differences found here most likely occurred because the pilot hole merely translated the stress concentration laterally to a parallel point on the surface of the hole. Cite this article: K. Bujnowski, A. Getgood, K. Leitch, J. Farr, C. Dunning, T. A. Burkhart. A pilot hole does not reduce the strains or risk of fracture to the lateral cortex during and following a medial opening wedge high tibial osteotomy in cadaveric specimens. Bone Joint Res 2018;7:166–172. DOI: 10.1302/2046-3758.72.BJR-2017-0337.R1.

Currently available knee joint kinematic tracking systems fail to nondestructively capture the subtle variation in joint and soft tissue kinematics that occur in native, injured, and reconstructed joint states. Microcomputed tomography (CT) imaging has the potential as a noninvasive, high-resolution kinematic tracking system, but no dynamic simulators exist to take advantage of this. The purpose of this work was to develop and assess a novel micro-CT compatible knee joint simulator to quantify the knee joint's kinematic and kinetic response to clinically (e.g., pivot shift test) and functionally (e.g., gait) relevant loading. The simulator applies closed-loop, load control over four degrees-of-freedom (DOF) (internal/external rotation, varus/valgus rotation, anterior/posterior translation, and compression/distraction), and static control over a fifth degree-of-freedom (flexion/extension). Simulator accuracy (e.g., load error) and repeatability (e.g., coefficient of variation) were assessed with a cylindrical rubber tubing structure and a human cadaveric knee joint by applying clinically and functionally relevant loads along all active axes. Micro-CT images acquired of the joint at a loaded state were then used to calculate joint kinematics. The simulator loaded both the rubber tubing and the cadaveric specimen to within 0.1% of the load target, with an intertrial coefficient of variation below 0.1% for all clinically relevant loading protocols. The resultant kinematics calculated from the acquired images agreed with previously published values, and produced errors of 1.66 mm, 0.90 mm, 4.41 deg, and 1.60 deg with respect to anterior translation, compression, internal rotation, and valgus rotation, respectively. All images were free of artifacts and showed knee joint displacements in response to clinically and functionally loading with isotropic CT image voxel spacing of 0.15 mm. The results of this study demonstrate that the joint-motion simulator is capable of applying accurate, clinically and functionally relevant loads to cadaveric knee joints, concurrent with micro-CT imaging. Nondestructive tracking of bony landmarks allows for the precise calculation of joint kinematics with less error than traditional optical tracking systems.

Background Total knee arthroplasty is an effective treatment for osteoarthritis. Restoration of physiologic varus alignment may restore the native soft tissue tension and improve outcomes. Methods Six paired fresh-frozen knee specimens were used to perform total knee arthroplastys. The left and right sides of were randomly assigned to have either a physiologic alignment cut or a standard of care neutral alignment bony cut prior to the implantation. Loads of 100 and 200 N were applied at 0, 30, 60, and 90° of flexion and the magnitude of the medial and lateral compartment distraction was measured. The loads were applied with the knee specimen intact and post arthroplasty. Findings The physiologic alignment had no difference between medial and lateral gaps at either load. With 100 N of load the physiologic alignment had a greater gap at 90° than at full extension while the standard alignment had significantly more gap at 60° of flexion than full extension. The physiologic alignment had a significantly greater gap with the implant compared to the intact condition at both loads. The standard alignment had no significant difference in overall gap between the implant and intact condition with any load. Interpretation Although performing a physiologic aligned TKA resulted in medial-lateral soft tissue balance, the flexion gap was found to have greater magnitude than the intact knee. Notably, a neutral aligned TKA was found to be balanced, but also was found to recreate the intact knee flexion gaps. These results suggest that coronal plane stability can be achieved with physiologic alignment objectives, but the clinician needs to be aware of the potential to have greater laxity than the intact and neutral alignment surgical objectives.

Injury to the anterolateral ligament (ALL) has been reported to contribute to high-grade anterolateral laxity after anterior cruciate ligament (ACL) injury. Failure to address ALL injury has been suggested as a cause of persistent rotational laxity after ACL reconstruction. Lateral meniscus posterior root (LMPR) tears have also been shown to cause increased internal rotation of the knee.The purpose of this study was to determine the functional relationship between the ALL and LMPR in the control of internal rotation of the ACL-deficient knee. Specifically: (1) We asked if there was a difference in internal rotation among: the intact knee; the ACL-deficient knee; the ACL/ALL-deficient knee; the ACL/LMPR-deficient knee; and the ACL/ALL/LMPR-deficient knee. (2) We also asked if there was a difference in anterior translation among these conditions.Sixteen fresh frozen cadaveric knee specimens (eight men, mean age 79 years) were potted into a hip simulator (femur) and a 6 degree-of-freedom load cell (tibia). Rigid optical trackers were inserted into the proximal femur and distal tibia, allowing for the motion of the tibia with respect to the femur to be tracked during biomechanical tests. A series of points on the femur and tibia were digitized to create bone coordinate systems that were used to calculate internal rotation and anterior translation. Biomechanical testing involved applying a 5-Nm internal rotation moment to the tibia from full extension to 90° of flexion. Anterior translation was performed by applying a 90-N anterior load using a tensiometer. Both tests were performed in 15° increments tested sequentially in the following conditions: (1) intact; and (2) ACL injury (ACL-). The specimens were then randomized to either have the ALL sectioned (3) first (M+/ALL-); or (4) the LMPR sectioned first (M-/ALL+) followed by the other structure (M-/ALL-). A one-way analysis of variance was performed for each sectioning condition at each angle of knee flexion (α = 0.05).At 0° of flexion there was an effect of tissue sectioning such that internal rotation of the M-/ALL- condition was greater than ACL- by 1.24° (p = 0.03; 95% confidence interval [CI], 0.16-2.70) and the intact condition by 2.5° (p = 0.01; 95% CI, 0.69-3.91). In addition, the mean (SD) internal rotations for the M+/ALL- (9.99° [5.39°]) and M-/ALL+ (12.05° [5.34°]) were greater by 0.87° (p = 0.04; 95% CI, 0.13-3.83) and by 2.15°, respectively, compared with the intact knee. At 45° the internal rotation for the ACL- (19.15° [9.49°]), M+/ALL- (23.70° [7.00°]), and M-/ALL- (18.80° [8.27°]) conditions was different than the intact (12.78° [9.23°]) condition by 6.37° (p = 0.02; 95% CI, 1.37-11.41), 8.47° (p 0.01; 95% CI, 3.94-13.00), and 6.02° (p = 0.01; 95% CI, 1.73-10.31), respectively. At 75° there was a 10.11° difference (p 0.01; 95% CI, 5.20-15.01) in internal rotation between the intact (13.96° [5.34°]) and the M+/ALL- (23.22° [4.46°]) conditions. There was also a 4.08° difference (p = 0.01; 95% CI, 1.14-7.01) between the intact and M-/ALL- (18.05° [7.31°]) conditions. Internal rotation differences of 6.17° and 5.43° were observed between ACL- (16.28° [6.44°]) and M+/ALL- (p 0.01; 95% CI, 2.45-9.89) as well as between M+/ALL- and M-/ALL- (p = 0.01; 95% CI, -8.17 to -1.63). Throughout the range of flexion, there was no difference in anterior translation with progressive section of the ACL, meniscus, or ALL.The ALL and LMPR both play a role in aiding the ACL in controlling internal rotation laxity in vitro; however, these effects seem to be dependent on flexion angle. The ALL has a greater role in controlling internal rotation at flexion angles 30Injury to the ALL and/or LMPR may contribute to high-grade anterolateral laxity after ACL injury. The LMPR and the ALL, along with the iliotibial tract, appear to act in concert as secondary stabilizers of anterolateral rotation and could be considered as the "anterolateral corner" of the knee.

Soft and rigid tissue mass prediction equations have been previously developed and validated for the segments of the upper and lower extremities in living humans using simple anthropometric measurements. The reliability of these measurements has been found to be good to excellent for all measurement types (segment lengths, circumferences, breadths, skinfolds). However, the reliability of the measurements needed to develop corresponding equations for the head, neck, and trunk has yet to be determined. The purpose of this study was to quantify the inter- and intrameasurer reliability of 34 surface anthropometric measurements of the head, neck, and trunk segments. Measurements (11 lengths, 7 circumferences, 11 breadths, 5 skinfolds) were taken twice separately on 50 healthy, university-age individuals using standard anthropometric tools. The mean inter- and intrameasurer measurement differences were fairly small overall, with 64.7% and 67.6% of the relative differences less than 5%, respectively. All measurements, except for the right lateral trunk, had intraclass correlation coefficients (ICCs) greater than 0.75, and coefficients of variation (CVs) less than 10%, indicating good reliability overall. These results are consistent with previous work for the extremities and provide support for the use of the defined surface measurements for future tissue mass prediction equation development.

© 2017, European Society of Sports Traumatology, Knee Surgery, Arthroscopy (ESSKA). Purpose: The purpose of the current investigation was to characterize biomechanical differences between the supra- and infra-meniscal sections of the anterolateral ligament (ALL). We hypothesized that the supra-meniscal fibers of the ALL would be stronger and stiffer than the infra-meniscal fiber. Methods: Nine cadaveric knee specimens [mean (SD) age = 79 (14.6) years] were dissected to identify the borders of the ALL while maintaining the anatomy of the lateral meniscus. The specimens were randomly assigned to either a supra-meniscal (the ALL below the meniscus was sectioned leaving only the supra-meniscal ALL intact) or an infra-meniscal (the ALL above the meniscus was sectioned leaving only the infra-meniscal attachment intact) group. The specimens were potted into dental cement such that the ALL was pulling laterally on the meniscus when the specimens were secured within an Instron materials testing machine. The specimens were subjected to a tensile failure test at 1 mm/s. The load at failure and stiffness were calculated from the force–displacement curves, while peak stress was calculated by normalizing the peak force to the cross-sectional area of the ALL. Furthermore, one intact knee specimen was used to perform a histological analysis on the two ALL sections using Masson’s Trichome staining. Results: The infra-meniscal ALL had a significantly (p = 0.03) higher load to failure (195.0 vs. 132.1 N) and was significantly (p = 0.03) stiffer than the supra-meniscal fibers (24.8 vs. 12.3 N/mm). The relatively similar cross-section areas also resulted in the infra-meniscal sections having a greater peak stress (p = 0.04) (11.1 vs. 5.4 MPa). Histological analysis showed relatively consistent fiber orientation with similar organization noted throughout the fibers. Conclusions: The ALL-meniscal construct that includes the infra-meniscal fibers was significantly stronger and stiffer than the construct that includes the supra-meniscal fibers. The infra-meniscal ALL is another important component of the anterolateral complex of the knee, and should be considered when presented with an ACL and/or meniscal injury.

A result of below-knee amputations (BKAs) is abnormal motion that occurs about the proximal tibiofibular joint (PTFJ). While it is known that joint morphology may play a role in joint kinematics, this is not well understood with respect to the PTFJ. Therefore, the purposes of this study were: (i) to characterize the anatomy of the PTFJ and statistically analyze the relationships within the joint; and (ii) to determine the relationships between the PTFJ characteristics and the degree of movement of the fibula in BKAs. The PTFJ was characterized in 40 embalmed specimens disarticulated at the knee, and amputated through the mid-tibia and fibula. Four metrics were measured: inclination angle (angle at which the fibula articulates with the tibia); tibial and fibular articular surface areas; articular surface concavity and shape. The specimens were mechanically tested by applying a load through the biceps femoris tendon, and the degree of motion about the tibiofibular joint was measured. Regression analyses were performed to determine the relationships between the different PTFJ characteristics and the magnitude of fibular abduction. Finally, Pearson correlation analyses were performed on inclination angle and surface area vs. fibular kinematics. The inclination angle measured on the fibula was significantly greater than that measured on the tibia. This difference may be attributed to differences in concavity of the tibial and fibular surfaces. Surface area measured on the tibia and fibula was not statistically different. The inclination angle was not statistically correlated to surface area. However, when correlating fibular kinematics in BKAs, inclination angle was positively correlated to the degree of fibular abduction, whereas surface area was negatively correlated. The characteristics of the PTFJ dictate the amount of fibular movement, specifically, fibular abduction in BKAs. Predicting BKA complications based on PTFJ characteristics can lead to recommendations in treatment.

The use of finite element models as research tools in biomechanics and orthopedics has grown exponentially over the last 20 years. However, the attention to mesh quality, model validation and appropriate energy balance methods and the reporting of these metrics has not kept pace with the general use of finite element modeling. Therefore, the purpose of this review was to summarize the current state of finite element modeling validation practices from the literature in biomechanics and orthopedics and to present specific methods and criteria limits that can be used as guidelines to assess mesh quality, validate simulation results and address energy balance issues. Of the finite element models reviewed from the literature, approximately 42% of them were not adequately validated, while 95% and 98% of the models did not assess the quality of the mesh or energy balance, respectively. A review of the methods that can be used to assess the quality of a mesh (e.g., aspect ratios, angle idealization and element Jacobians), measure the balance of energies (e.g., hour glass energy and mass scaling), and quantify the accuracy of the simulations (e.g., validation metrics, corridors, statistical techniques) are presented.

The purpose of this study was to develop a multivariate distal radius injury risk prediction model that incorporates dynamic loading variables in multiple directions, and interpret the distal radius failure data in order to establish injury probability thresholds. Repeated impacts with increasing intensity were applied to the distal third of eight human cadaveric radius specimens (mean (SD) age=61.9 (9.7)) until injury occurred. Crack (non-propagating damage) and fracture (specimen separated into at least two fragments) injury events were recorded. Best subsets analysis was performed to find the best multivariate injury risk model. Force-only risk models were also determined for comparison. Cumulative distribution functions were developed from the parameters of a Weibull analysis and the forces and risk scores (i.e., values calculated from the injury risk models) from 10% to 90% probability were calculated. According to the adjusted R(2), variance inflation factor and p-values, the model that best predicted the crack event included medial/lateral impulse, Fz load rate, impact velocity and the natural logarithm of Fz (Adj. R(2)=0.698), while the best predictive model of the fracture event included medial/lateral impulse, impact velocity and peak Fz (Adj. R(2)=0.845). The multivariate models predicted injury risk better than both the Fz-only crack (Adj. R(2)=0.551) and fracture (Adj. R(2)=0.293) models. Risk scores of 0.5 and 0.6 corresponded to 10% failure probability for the crack and fracture events, respectively. The inclusion of medial/lateral impulse and impact velocity in both crack and fracture models, and Fz load rate in the crack model, underscores the dynamic nature of these events. This study presents a method capable of developing a set of distal radius fracture prediction models that can be used in the assessment and development of distal radius injury prevention interventions.

The occurrence of distal upper extremity injuries resulting from forward falls (approximately 165,000 per year) has remained relatively constant for over 20 years. Previous work has provided valuable insight into fall arrest strategies, but only symmetric falls in body postures that do not represent actual fall scenarios closely have been evaluated. This study quantified the effect of asymmetric loading and body postures on distal upper extremity response to simulated forward falls. Twenty participants were suspended from the Propelled Upper Limb fall ARest Impact System (PULARIS) in different torso and leg postures relative to the ground and to the sagittal plane (0°, 30° and 45°). When released from PULARIS (hands 10 cm above surface, velocity 1 m/s), participants landed on two force platforms, one for each hand. Right forearm impact response was measured with distal (radial styloid) and proximal (olecranon) tri-axial accelerometers and bipolar EMG from seven muscles. Overall, the relative height of the torso and legs had little effect on the forces, or forearm response variables. Muscle activation patterns consistently increased from the start to the peak activation levels after impact for all muscles, followed by a rapid decline after peak. The impact forces and accelerations suggest that the distal upper extremity is loaded more medial-laterally during asymmetric falls than symmetric falls. Altering the direction of the impact force in this way (volar-dorsal to medial-lateral) may help reduce distal extremity injuries caused when landing occurs symmetrically in the sagittal plane as it has been shown that volar-dorsal forces increase the risk of injury.

This study sought to compare a new head impact-monitoring device, which is not limited to specific helmet styles, against reference accelerometer measurements. Laboratory controlled impacts were delivered using a linear pneumatic impactor to a Hybrid III headform (HIII) fitted with a football helmet and the impact monitoring device (gForce Tracker-GFT) affixed to the inside of the helmet. Linear regression analyses and absolute mean percent error (MAPE) were used to compare the head impact kinematics measured by the GFT to a reference accelerometer located at the HIII's center of mass. The coefficients of determination were strong for the peak linear acceleration, peak rotational velocity, and HIC15 across all impact testing locations (r(2) = 0.82, 0.94, and 0.70, respectively), but there were large MAPE for the peak linear acceleration and HIC15 (MAPE = 49 ± 21% and 108 ± 58%). The raw GFT was accurate at measuring the peak rotational velocity at the center of mass of the HIII (MAPE = 9%). Results from the impact testing were used to develop a correction algorithm. The coefficients of determination for all impact parameters improved using the correction algorithm for the GFT (r(2) > 0.97), and the MAPE were less than 14%. The GFT appears to be a suitable impact-monitoring device that is not limited to specific styles of football helmets, however, correction algorithms will need to be developed for each helmet style.

Background: Anatomic anterolateral ligament (ALL) reconstruction has been proposed to assist anterior cruciate ligament (ACL) reconstruction in controlling anterolateral rotational laxity of the knee. However, the biomechanical effects have not been reported. Purpose: (1) To investigate the effect of ALL transection on rotational knee kinematics and (2) to determine the effect on knee biomechanics of ALL reconstruction procedures compared with lateral extra-articular tenodesis (LET). Study Design: Controlled laboratory study. Methods: A total of 12 cadaveric knee specimens were tested in the following sequence: (1) ACLintact, (2) anteromedial bundle of ACL sectioned (ACLamb), (3) complete ACL sectioned (ACLfull), (4) ALL sectioned (ALLsec), (5) anatomic ALL reconstruction (ALLanat), and (6) LET. Biomechanical anterior drawer and Lachman tests were performed in which a 90-N load was applied to the posterior tibia, and anterior translation was measured. A combined load to simulate the early phase of the pivot-shift test was executed in which a 5-N·m internal rotation moment was applied to a fully extended knee; anterior translation and internal rotation were measured. Results: Anterior translation increased across conditions for the biomechanical tests. Internal rotation during the simulated early-phase pivot-shift test was significantly different between ACLfull and ALLsec. Anatomic ALL reconstruction did not significantly reduce internal rotation or anterior translation during the simulated early-phase pivot-shift test. After LET, a significant decrease in anterior translation was found. There was no evidence of overconstraint of the knee with either anatomic ALL reconstruction or LET. Conclusion: The ALL demonstrated a role in controlling anterolateral laxity. LET had a composite effect in governing both anterior and rotational laxity. Anatomic ALL reconstruction did not reduce anterolateral rotational laxity. Clinical Relevance: Profiling the biomechanical characteristics of anterolateral reconstruction is integral to understanding the implications and potential benefit of such an additional procedure to ACL reconstruction.