The Effect of Lateral Extra-articular Tenodesis in an ACL-Reconstructed Knee With Partial Medial Meniscectomy: A Biomechanical Study.

Background: Knee laxity increases with medial meniscectomy in anterior cruciate ligament (ACL)-reconstructed knees; however, the biomechanical effect of an additional lateral extra-articular tenodesis (LET) is unknown.

Purpose/hypothesis: The purpose of this study was to determine the kinematic effect of a LET in knees that underwent combined ACL reconstruction (ACL-R) and partial medial meniscus posterior horn (MMPH) meniscectomy. It was hypothesized that the addition of LET would reduce laxity in the ACL-reconstructed knee.

Relative contributions of the supraspinatus cord and strap tendons to shoulder abduction and translation.

Background: The supraspinatus (SS) is formed by a larger anterior bipennate muscle with a cord-like tendon and a posterior unipennate muscle with a strap-like tendon. There is a tendinous connection between the 2 SS subunits. Yet, the relative mechanical contribution of the SS cord and SS strap musculotendinous units to load transmission and subsequent shoulder abduction force is unknown.

The pathoanatomy of atraumatic partial distal biceps tears: a cadaveric study.

Background: Partial distal biceps tears can occur in the short and/or long heads, leading to forearm pain and weakness. Yet, the pathoanatomy of atraumatic and traumatic partial tears are not understood. The goals of this study are to determine the distal biceps partial tear frequency and tear pattern in a cohort of cadaveric specimens.

Augmenting ACL Repair With Suture Tape Improves Knee Laxity: A Biomechanical Study.

Background: Anterior cruciate ligament (ACL) repair is an alternative to reconstruction; however, suture tape support may be necessary to achieve adequate outcomes.

Purposes: To investigate the influence of suture tape augmentation (STA) of proximal ACL repair on knee kinematics and to evaluate the effect of the 2 flexion angles of suture tape fixation.

Study Design: Controlled laboratory study.

No Difference in Knee Kinematics Between Anterior Cruciate Ligament-First and Posterior Cruciate Ligament-First Fixation During Single-Stage Multiligament Knee Reconstruction: A Biomechanical Study.

Background: For combined reconstruction of both the anterior cruciate ligament (ACL) and the posterior cruciate ligament (PCL), there is no consensus regarding which graft should be tensioned and fixed first.

Purpose: The purpose of this study was to determine which sequence of graft tensioning and fixation better restores normal knee kinematics. The hypothesis was that ACL-first fixation would more closely restore normal knee kinematics, graft force, and the tibiofemoral orientation in the neutral (resting) position compared with PCL-first fixation.

Arthroscopic centralization reduces extrusion of the medial meniscus with posterior root defect in the ACL reconstructed knee.

Purpose: The purpose of this study was to evaluate the effects of arthroscopic meniscal centralization reinforcement for a medial meniscus (MM) posterior root defect on knee kinematics and meniscal extrusion in the anterior cruciate ligament reconstructed (ACLR) knee. The hypothesis was that the medial meniscus centralization would reduce extrusion and anterior laxity in ACLR knee with a medical meniscal defect.

Methods: Fourteen fresh-frozen human cadaveric knees were tested using a six-degrees-of-freedom robotic system under the following loading conditions: (a) an 89.

The Rotator Cable Does Not Stress Shield the Crescent Area During Shoulder Abduction.

Background: It is accepted by the orthopaedic community that the rotator cable (RCa) acts as a suspension bridge that stress shields the crescent area (CA). The goal of this study was to determine if the RCa does stress shield the CA during shoulder abduction.

Methods: The principal strain magnitude and direction in the RCa and CA and shoulder abduction force were measured in 20 cadaveric specimens.

Arthroscopic Centralization for Lateral Meniscal Injuries Reduces Laxity in the Anterior Cruciate Ligament-Reconstructed Knee.

Background: A lateral meniscal (LM) disorder is one factor that causes rotational laxity after anterior cruciate ligament (ACL) reconstruction (ACLR). There are different types of irreparable meniscal disorders, one of which is a massive meniscal defect.

Hypothesis/purpose: The purpose of this study was to evaluate the kinematic effects of arthroscopic centralization on an irreparable LM defect.

ACL graft with extra-cortical fixation rotates around the femoral tunnel aperture during knee flexion.

Purpose: An understanding of the behavior of a new ACL graft in the femoral tunnel during knee motion and external loading can provide information pertinent to graft healing, tunnel enlargement, and graft failure. The purpose of the study was to measure the percentage of the tunnel filled by the graft and determine the amount and location of the graft-tunnel contact with knee motion and under external knee loads.

Methods: Single bundle anatomical ACL reconstruction was performed on six cadaveric knees.

Low to moderate risk of nerve damage during peroneus longus tendon autograft harvest.

Purpose: This study aims to evaluate the proximity of the tendon stripper to both the peroneal and sural nerves during peroneus longus tendon (PLT) autograft harvesting.

Methods: Ten fresh-frozen human cadaveric lower extremities were used to harvest a full-thickness PLT autograft using a standard closed blunt-ended tendon stripper. The distance to the sural nerve from the PLT (at 0, 1, 2 and 3 cm proximal to lateral malleolus (LM), and the distance to the peroneal nerve and its branches from the end of the tendon stripper were measured by two separate observers using ImageJ software.

Locating the rotator cable during subacromial arthroscopy: bursal- and articular-sided anatomy.

Background: The rotator cable (RCa) is an important articular-sided structure of the cuff capsular complex that helps prevent suture pull out during rotator cuff repairs (RCRs) and plays a role in force transmission. Yet, the RCa cannot be located during bursal-sided RCRs. The purpose of this study is to develop a method to locate the RCa in the subacromial space and compare its bursal- and articular-sided dimensions.

Effect of Percentage of Femoral Anterior Cruciate Ligament Insertion Site Reconstructed With Hamstring Tendon on Knee Kinematics and Graft Force.

Background: Previous studies have stated that closely matching the size of the anterior cruciate ligament (ACL) insertion site footprint is important for biomechanical function and clinical stability after ACL reconstruction. However, the ACL varies widely regarding the area of femoral insertion, tibial insertion, and midsubstance of ACL, and reconstructing the insertion site area with a uniform diameter graft can result in a cross-sectional area that is greater than that of the midsubstance of the native ACL. Therefore, understanding the effect of relative graft size in ACL reconstruction on knee biomechanics is important for surgical planning.

Partial Distal Biceps Avulsion Results in a Significant Loss of Supination Force.

Background: Partial avulsions of the short and/or long head of the distal biceps tendon cause pain and loss of strength. The goal of the present study was to quantify the loss of supination and flexion strength following a series of surgical releases designed to simulate partial and complete short and long head traumatic avulsions.

Methods: Mechanical testing was performed to measure supination moment arms and flexion force efficiency on 18 adult fresh-frozen specimens in pronation, neutral, and supination.

Suture tape augmentation improves laxity of MCL repair in the ACL reconstructed knee.

Purpose: Medial collateral ligament (MCL) injury is very common and surgical repair is sometimes necessary. Especially in the setting of simultaneous anterior cruciate ligament reconstruction (ACLR) as the ACL is the secondary restraint against valgus stress. The goal of this study was to evaluate knee biomechanics after suture repair of the MCL augmented with suture tape, as compared to MCL repair alone, in the setting of concomitant ACL reconstruction (ACLR).

Peroneus longus tendon autograft has functional outcomes comparable to hamstring tendon autograft for anterior cruciate ligament reconstruction: a systematic review and meta-analysis.

Purpose: This review aimed to assess whether peroneus longus tendon (PLT) autograft would have comparable functional outcomes and graft survival rates when compared to hamstring tendon (HT) autograft for anterior cruciate ligament (ACL) reconstruction.

Methods: PubMed, Web of Science, Cochrane Library, Ovid (MEDICINE), and EMBASE databases were queried for original articles from clinical studies including the keywords: ACL reconstruction and PLT autograft. Studies comparing PLT autograft versus HT autograft were included in this analysis and the following data were extracted from studies meeting the inclusion criteria: graft diameter, functional outcomes (Tegner activity scale, Lysholm score, and International Knee Documentation Committee (IKDC) subjective score), knee laxity (Lachman test), and complications (donor site pain or paresthesia, graft failure).

Partial meniscectomy does not affect the biomechanics of anterior cruciate ligament reconstructed knee with a lateral posterior meniscal root tear.

Purpose: The purpose of this study was to determine the effects of a lateral meniscus posterior root tear, partial meniscectomy, and total meniscectomy on knee biomechanics in the setting of anterior cruciate ligament (ACL) reconstruction.

Methods: Thirteen fresh-frozen cadaver knees were tested with a robotic testing system under an 89.0-N anterior tibial load at full extension (FE), 15°, 30°, 60° and 90° of knee flexion and a simulated pivot-shift loading (7.

Single-bundle MCL reconstruction with anatomic single-bundle ACL reconstruction does not restore knee kinematics.

Purpose: The purpose of this study was to evaluate and compare knee kinematics and kinetics following either single bundle, modified triangular or double-bundle reconstruction of the superficial medial collateral ligament (sMCL) with single bundle anatomic ACL reconstruction.

Methods: Using a cadaveric model (n = 10), the knee kinematics and kinetics following three MCL reconstructions (single-bundle (SB), double-bundle (DB), modified triangular) with single bundle anatomic ACL reconstruction were compared with the intact and deficient knee state. The knees were tested under (1) an 89-N anterior tibial load, (2) 5 N-m internal and external rotational tibial torques, and (3) a 7 N-m valgus torque.

The effect of tendon rotation on distal biceps repair.

Background: The distal biceps tendon externally rotates from proximal to distal before inserting onto the radius. Our hypothesis is that an externally rotated (anatomic) repair would re-create native supination moment arm and flexion force, whereas an internally rotated (nonanatomic) repair would result in reduced force transmission.

Methods: The mechanical tests performed in this study measured isometric moment arms and elbow flexion force using a validated elbow simulator as previously published.

Notchplasty alters knee biomechanics after anatomic ACL reconstruction.

Purpose: The aims of this study were (1) to study the biomechanics of single-bundle anatomic ACL reconstructed knees with and without notchplasty using a robotic testing system and (2) to determine if there would be a difference between performing a small or large notchplasty.

Methods: Fifteen fresh-frozen specimens were used in this study. The ACL reconstruction (ACL-R) was performed using an anatomic single-bundle technique with the 8 mm soft tissue graft fixed at 30° with suspensory fixation on the femoral side and a screw and washer on the tibial side.

The femoral posterior fan-like extension of the ACL insertion increases the failure load.

Purpose: To examine the role of the posterior fan-like extension of the ACL's femoral footprint on the ACL failure load.

Methods: Sixteen (n = 16) fresh frozen, mature porcine knees were used in this study and randomized into two groups (n = 8): intact femoral ACL insertion (ACL intact group) and cut posterior fan-like extension of the ACL (ACL cut group). In the ACL cut group, flexing the knees to 90°, created a folded border between the posterior fan-like extension and the midsubstance insertion of the femoral ACL footprint and the posterior fan-like extension was dissected and both areas were measured.

Arthroscopic centralization restores residual knee laxity in ACL-reconstructed knee with a lateral meniscus defect.

Purpose: The aim of this study was to evaluate the effects of knee biomechanics with an irreparable lateral meniscus defect using the centralization capsular meniscus support procedure in the setting of the ACL-reconstructed knee in a porcine model. The hypothesis is the arthroscopic centralization will decrease the laxity and rotation of the ACL-reconstructed knee.

Methods: Twelve fresh-frozen porcine knees were tested using a robotic testing system under the following loading conditions: (a) an 89.

Clinical and functional impairment after nonoperative treatment of distal biceps ruptures.

Background: Clinical and functional impairment after nonoperative treatment of distal biceps ruptures is not well understood. The goal of this study was to measure patients' perceived disability, kinematic adjustment, and forearm supination power after nonoperative treatment of distal biceps ruptures.

Methods: Fourteen individuals after nonoperative treatment of distal biceps ruptures were matched to a control group of 18 uninjured volunteers.

Lateral Meniscal Posterior Root Repair With Anterior Cruciate Ligament Reconstruction Better Restores Knee Stability.

Background: The effect of lateral meniscal posterior root tear and repair-commonly seen in clinical practice in the setting of anterior cruciate ligament (ACL) reconstruction-is not known.

Purpose/hypothesis: This study evaluated the effect of tear and repair of the lateral meniscal posterior root on the biomechanics of the ACL-reconstructed knee. It was hypothesized that anterior tibial translation would increase under anterior loading and simulated pivot-shift loading with the root tear of the posterior lateral meniscus, while repair of the root tear would reduce it close to the noninjured state.

Coronal tibial anteromedial tunnel location has minimal effect on knee biomechanics.

Purpose: Studies have found anatomic variation in the coronal position of the insertion site of anteromedial (AM) bundle of the anterior cruciate ligament (ACL) on the tibia, which can lead to questions about tunnel placement during ACL reconstruction. The purpose of this study was to determine how mediolateral placement of the tibial AM graft tunnel in double-bundle ACL reconstructions affects knee biomechanics.

Methods: Two different types of double-bundle ACL reconstructions were performed.