Association of the COVID-19 Pandemic With Outcomes After Anterior Cruciate Ligament Reconstruction: A Retrospective Comparative Study Examining Changes in Health Care Access, Delivery, and Functional Outcomes.

Background: Structured rehabilitation optimizes outcomes and reduces reinjury risk after anterior cruciate ligament reconstruction (ACLR). The coronavirus 2019 (COVID-19) pandemic interrupted standard rehabilitation, possibly affecting ACLR outcomes.

Purpose: To characterize changes to ACLR functional outcomes related to the COVID-19 pandemic.

Effects of General Anesthesia Plus Multimodal Analgesia on Immediate Perioperative Outcomes of Hamstring Tendon Autograft ACL Reconstruction: A Randomized, Double-Blinded, Placebo-Controlled Trial.

Unlabelled: Anterior cruciate ligament reconstruction with hamstring tendon autograft (H-ACLR) is a standard ambulatory procedure with the potential for considerable postoperative pain. We hypothesized that general anesthesia combined with a multimodal analgesia regimen would reduce postoperative opioid use associated with H-ACLR.

Methods: This study was a single-center, surgeon-stratified, double-blinded, placebo-controlled, randomized clinical trial.

Periostin modulates extracellular matrix behavior in tendons.

Periostin, originally named osteoblast-specific factor 2 (OSF-2) has been identified primarily in collagen rich, biomechanically active tissues where its role has been implicated in mechanisms to maintain the extracellular matrix (ECM), including collagen fibrillogenesis and crosslinking. It is well documented that periostin plays a role in wound healing and scar formation after injury, in part, by promoting cell proliferation, myofibroblast differentiation, and/or collagen fibrillogenesis. Given the significance of periostin in other scar forming models, we hypothesized that periostin will influence Achilles tendon healing by modulating ECM production.

Risk Factors for Athletic Pubalgia in Collegiate Football Student-Athletes: A Retrospective Cohort Study.

Background: Athletic pubalgia (AP) is an increasingly recognized injury among young athletes. This study aimed to evaluate the characteristics associated with AP in college football players.

Hypothesis: Repetitive explosive movements that require aggressive core muscle activation results in AP in collegiate football players.

Pitching Behaviors in Youth Fast-Pitched Softball: High Pitching Volumes With Unequal Pitch Counts Among Pitchers are Common.

Background: Softball is a popular sport among youth female athletes. While youth baseball has well-established, evidence-based pitching guidelines, youth softball pitching guidelines lack both evidence and enforcement. Adherence to pitch count limits in youth softball is infrequent and results in pitchers with exceedingly high pitching volumes.

Quantifying the differential functional behavior between the medial and lateral meniscus after posterior meniscus root tears.

Meniscus tears of the knee are among the most common orthopedic knee injury. Specifically, tears of the posterior root can result in abnormal meniscal extrusion leading to decreased function and progressive osteoarthritis. Despite contemporary surgical treatments of posterior meniscus root tears, there is a low rate of healing and an incidence of residual meniscus extrusion approaching 30%, illustrating an inability to recapitulate native meniscus function.

Running Biomechanics Before Injury and 1 Year After Anterior Cruciate Ligament Reconstruction in Division I Collegiate Athletes.

Background: Preinjury running biomechanics are an ideal comparator for quantifying recovery after anterior cruciate ligament (ACL) reconstruction (ACLR), allowing for assessments within the surgical and nonsurgical limbs. However, availability of preinjury running biomechanics is rare and has been reported in case studies only.

Purpose/hypothesis: The purpose of this study was to determine if running biomechanics return to preinjury levels within the first year after ACLR among collegiate athletes.

Anterior Cruciate Ligament Graft Tunnel Placement and Graft Angle Are Primary Determinants of Internal Knee Mechanics After Reconstructive Surgery.

Background: Graft placement is a modifiable and often discussed surgical factor in anterior cruciate ligament (ACL) reconstruction (ACLR). However, the sensitivity of functional knee mechanics to variability in graft placement is not well understood.

Purpose: To (1) investigate the relationship of ACL graft tunnel location and graft angle with tibiofemoral kinematics in patients with ACLR, (2) compare experimentally measured relationships with those observed with a computational model to assess the predictive capabilities of the model, and (3) use the computational model to determine the effect of varying ACL graft tunnel placement on tibiofemoral joint mechanics during walking.

Intraoperative Conversion to Five-Strand Hamstring Autograft Configuration Significantly Increases Anterior Cruciate Ligament Graft Diameter Independent of Patient Characteristics.

Intraoperative conversion of a four-strand hamstring autograft to a five-strand configuration during an anterior cruciate ligament (ACL) reconstruction has been reported. However, the expected change in graft size and the dependence on patient characteristics are currently not well described. The purpose of this study was to determine the effective change in hamstring graft diameter and reliance on patient characteristics when intraoperatively converting a four-strand hamstring autograft into a five-strand configuration during an ACL reconstruction.

Extracellular Vesicle-Educated Macrophages Promote Early Achilles Tendon Healing.

Tendon healing follows a complex series of coordinated events, which ultimately produces a mechanically inferior tissue more scar-like than native tendon. More regenerative healing occurs when anti-inflammatory M2 macrophages play a more dominant role. Mesenchymal stromal/stem cells (MSCs) are able to polarize macrophages to an M2 immunophenotype via paracrine mechanisms.

American Society of Biomechanics Clinical Biomechanics Award 2017: Non-anatomic graft geometry is linked with asymmetric tibiofemoral kinematics and cartilage contact following anterior cruciate ligament reconstruction.

Background: Abnormal knee mechanics may contribute to early cartilage degeneration following anterior cruciate ligament reconstruction. Anterior cruciate ligament graft geometry has previously been linked to abnormal tibiofemoral kinematics, suggesting this parameter may be important in restoring normative cartilage loading. However, the relationship between graft geometry and cartilage contact is unknown.

Osteochondral Graft Size Is Significantly Associated With Increased Force and Decreased Chondrocyte Viability.

Background: Insertion force has been shown to significantly reduce chondrocyte viability during osteochondral allograft transplantation. How graft size influences the required insertion force and chondrocyte viability has yet to be determined. Hypothesis/Purpose: The purpose was to characterize how graft size influences insertion force requirements and chondrocyte viability during osteochondral transplantation.

Level-specific amputations and resulting regenerative outcomes in the mouse distal phalanx.

Mouse digit tip regeneration involves an intricate coordinated regrowth of the terminal phalanx, nail, dermis and epidermis. During this time, regenerating digits undergo wound healing, blastema formation, and differentiation. However, the regenerative response of the digit is dependent on the level of the amputation.

Intratendinous injections of platelet-rich plasma: feasibility and effect on tendon morphology and mechanics.

Background: Intratendinous injections may have important effects on the properties of collagen microarchitecture, morphology, and subsequent mechanical properties of the injected tendon. The purpose of this study was to examine the effects of intratendinous PRP injections; the injectant retention within tendons, the distribution of intratendinous injectant, and whether intratendinous injection or needle fenestration alters tendon morphology or mechanics.

Design: Controlled Laboratory Study.

Influence of tendon tears on ultrasound echo intensity in response to loading.

Acoustoelastic (AE) ultrasound image analysis is a promising non-invasive approach that uses load-dependent echo intensity changes to characterize stiffness of tendinous tissue. The purpose of this study was to investigate whether AE can detect localized changes in tendon stiffness due to partial and full-thickness tendon tears. Ovine infraspinatus tendons with different levels of damage (Intact, 33%, 66% and full thickness cuts initiated on the articular and bursal sides) were cyclically loaded in a mechanical testing system while cine ultrasound images were recorded.

Effects of BMP-12-releasing sutures on Achilles tendon healing.

Tendon healing is a complex coordinated event orchestrated by numerous biologically active proteins. Unfortunately, tendons have limited regenerative potential and as a result, repair may be protracted months to years. Current treatment strategies do not offer localized delivery of biologically active proteins, which may result in reduced therapeutic efficacy.

Interleukin-1 receptor antagonist modulates inflammation and scarring after ligament injury.

Ligaments have limited regenerative potential and as a consequence, repair is protracted and results in a mechanically inferior tissue more scar-like than native ligament. We previously reported that a single injection of interleukin-1 receptor antagonist (IL-1Ra) delivered at the time of injury, decreased the number of M2 macrophage-associated inflammatory cytokines. Based on these results, we hypothesized that IL-1Ra administered after injury and closer to peak inflammation (as would occur clinically), would more effectively decrease inflammation and thereby improve healing.

The influence of partial and full thickness tears on infraspinatus tendon strain patterns.

Tears on the bursal and articular sides of the rotator cuff tendons are known to behave differently and strain is thought to play a role in this difference. This study investigates the effect of tear location on the changes in three strain measurements (grip-to-grip, insertion, and mid-substance tissue) in a sheep infraspinatus tendon model during axial loading. We introduced a 14 mm wide defect near the insertion from either the articular or bursal side of the tendon to three depths (3 mm, 7 mm & full) progressively.

Interleukin expression after injury and the effects of interleukin-1 receptor antagonist.

Ligament healing follows a series of complex coordinated events involving various cell types, cytokines, as well as other factors, producing a mechanically inferior tissue more scar-like than native tissue. Macrophages provide an ongoing source of cytokines to modulate inflammatory cell adhesion and migration as well as fibroblast proliferation. Studying interleukins inherent to ligament healing during peak macrophage activation and angiogenesis may elucidate inflammatory mediators involved in subsequent scar formation.

Evaluation of the articular cartilage of the knee joint: value of adding a T2 mapping sequence to a routine MR imaging protocol.

Purpose: To determine whether the addition of a T2 mapping sequence to a routine magnetic resonance (MR) imaging protocol could improve diagnostic performance in the detection of surgically confirmed cartilage lesions within the knee joint at 3.0 T.

Materials And Methods: This prospective study was approved by the institutional review board, and the requirement to obtain informed consent was waived.

Temporal healing in rat achilles tendon: ultrasound correlations.

The purpose of this study was to explore whether a new ultrasound-based technique correlates with mechanical and biological metrics that describe the tendon healing. Achilles tendons in 32 rats were unilaterally transected and allowed to heal without repair. At 7, 9, 14, or 29 days post-injury, tendons were collected and examined for healing via ultrasound image analysis, mechanical testing, and immunohistochemistry.

Sublabral clefts and recesses in the anterior, inferior, and posterior glenoid labrum at MR arthrography.

Purpose: To determine the prevalence of a normal variant cleft/recess at the labral-chondral junction in the anterior, inferior, and posterior portions of the shoulder joint.

Materials And Methods: One hundred and three consecutive patients (106 shoulders) who had a direct MR arthrogram followed by arthroscopic surgery were enrolled in this IRB-approved study. Scans were carried out on a 1.

Short-term clinical importance of osseous injuries diagnosed at MR imaging in patients with anterior cruciate ligament tear.

Purpose: To determine the association between osseous injuries and short-term clinical outcome in patients with anterior cruciate ligament (ACL) tear.

Materials And Methods: The retrospective study was performed with institutional review board approval, and the requirement to obtain informed consent was waived. The study group consisted of 114 patients (57 male and 57 female patients with a mean age of 26.