Lynn Snyder-Mackler

Lynn Snyder-Mackler
University of Delaware | UDel UD · Department of Physical Therapy

PT, ScD, FAPTA

About

474
Publications
132,561
Reads
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26,888
Citations
Citations since 2016
124 Research Items
14658 Citations
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201620172018201920202021202205001,0001,5002,0002,500
201620172018201920202021202205001,0001,5002,0002,500

Publications

Publications (474)
Article
Objective: Evaluate patellofemoral cartilage health, as assessed by quantitative magnetic resonance imaging (qMRI) T2 relaxation times, 24-months after ACL reconstruction (ACLR) and determine if they were associated with patellofemoral contact forces and knee mechanics during gait 3 months after surgery. Design: Thirty individuals completed moti...
Article
Kinematic and kinetic changes following anterior cruciate ligament (ACL) rupture and reconstruction (ACLR) have been fundamental to the understanding of mechanical disrupted load as it contributes to the development of posttraumatic osteoarthritis. These analyses overlook the potential contribution of muscle activity as it relates to the joint load...
Article
Markerless motion capture (mocap) could be the future of motion analysis. The purpose of this report was to describe our team of clinicians and scientists’ exploration of markerless mocap (Theia 3D) and share data for others to explore (link: https://osf.io/6vh7z/?view_only=c0e00984e94a48f28c8d987a2127339d). Simultaneous mocap was performed using m...
Article
Full-text available
Background Impairments and dysfunction vary considerably after anterior cruciate ligament (ACL) injury, and distinct subgroups may exist. Purpose (1) To identify subgroups of patients with ACL injury who share common trajectories of patient-reported knee function from initial presentation to 5 years after a treatment algorithm where they chose eit...
Article
Purpose: Bone-patellar tendon-bone (BPTB) graft harvest for anterior cruciate ligament reconstruction (ACLR) alters patellar tendon properties which inflict poor quadriceps neuromuscular function. BPTB autografts are associated with higher rates of post-traumatic osteoarthritis which in turn is associated with pathological gait. The purpose of thi...
Article
Full-text available
Background The 11+ program prevents anterior cruciate ligament (ACL) injuries in athletes through unknown mechanisms. Purpose The aim of the current study was to evaluate the effects of The 11+ intervention program, performed by female soccer players during a single season, on the frequency of Early Peaks during athletic tasks. Methods Three team...
Article
Interlimb and sex-based differences in gait mechanics and neuromuscular control are common after anterior cruciate ligament reconstruction (ACLR). Following ACLR, individuals typically exhibit elevated co-contraction of knee muscles, which may accelerate knee osteoarthritis (OA) onset. While directed (medial/lateral) co-contractions influence tibio...
Article
Objectives Trunk kinematics can contribute to lower extremity biomechanical risk factors for anterior cruciate ligament (ACL) injury. However, normative trunk kinematics during unilateral athletic tasks in a large population of “healthy” (no history of ACL injury and no known future ACL injury) women’s soccer players have not been well-described. T...
Article
Range of motion (ROM) and pain often define successful recovery after total knee arthroplasty (TKA), but these routine clinical outcomes correlate poorly or not at all to functional capacity after TKA. The purpose of this Perspective is to underscore the importance of muscle strength and performance-based functional tests in addition to knee ROM an...
Article
Background: Anterior cruciate ligament (ACL) registries do not all use the same patient-reported outcome measures, limiting comparisons and preventing pooling of data for meta-analysis. Our objective was to create a statistical crosswalk to convert cohort and registry mean Knee Injury and Osteoarthritis Outcome Scores (KOOS) to International Knee...
Article
Purpose: Asymmetrical gait mechanics after anterior cruciate ligament reconstruction (ACLR) are associated with development of post-traumatic knee osteoarthritis. Current measures of gait mechanics have focused heavily on peak magnitudes of knee kinematics, kinetics, and joint contact forces, but have seldom considered the rate of knee loading, cu...
Article
Osteoarthritis (OA) development after ACL reconstruction (ACLR) is common. Patellofemoral OA after ACLR is as prevalent as tibiofemoral OA; however, few have explored the mechanisms leading to disease development in this compartment. Biomechanical alterations may be one mechanism responsible for post-traumatic knee OA. Patellofemoral contact forces...
Article
Gait alterations after anterior cruciate ligament reconstruction (ACLR) are commonly reported and have been linked to posttraumatic osteoarthritis development. While knee gait alterations have been studied at several time points after ACLR, little is known about how these biomechanical variables change earlier than 6 months after surgery, nor is mu...
Article
Context: Anterior cruciate ligament (ACL) reconstruction (ACLR) and postoperative rehabilitation continues to be a multidisciplinary focus in both research and clinical environments. Recent research on ACLR warrants a reexamination of clinicians' current rehabilitation practices to optimize the strikingly variable clinical outcomes after ACLR and...
Article
Human health is affected by lived experiences, both past and present. The environments we encounter throughout our lives, therefore, shape how we respond to new challenges, how we maintain a healthy immune system, and even how we respond to treatment and rehabilitation. Early in life and throughout adulthood, social experiences—such as exposure to...
Conference Paper
Background Many non-contact anterior cruciate ligament (ACL) injuries amongst women’s soccer players occur during a deceleration manoeuvre. Retrospective video analysis of ACL injuries has demonstrated that players are often in knee valgus at the time of injury. Whether the components of valgus collapse: hip adduction, hip internal rotation, and kn...
Article
Background: Psychological readiness to return to sport has emerged as an important factor associated with outcomes after anterior cruciate ligament reconstruction (ACLR). Psychological factors are potentially modifiable during the course of rehabilitation, and improving them may lead to better outcomes. Purpose: To determine whether athletes wit...
Article
Background Despite the success rate of Total Knee Arthroplasty (TKA), many patients undergo contralateral TKA. It is possible that altered gait mechanics after unilateral TKA play a role in the progression of contralateral OA progression. Research question The purpose of this study was to identify biomechanical predictors of radiographic OA progre...
Article
Full-text available
Background Patients and clinicians often struggle to choose the optimal management strategy for posttraumatic knee osteoarthritis (OA) after an anterior cruciate ligament (ACL) injury. An evaluation of radiographic outcomes after a decision-making and treatment algorithm applicable in clinical practice can help to inform future recommendations and...
Article
Full-text available
Background: Valgus collapse and high knee abduction moments have been identified as biomechanical risk factors for ACL injury. It is unknown if participation in the 11+, a previously established, dynamic warm-up that emphasizes biomechanical technique and reduces ACL injury rates, reduces components of valgus collapse during a 90º cut. Hypothesis...
Article
Background: Anterior cruciate ligament (ACL) injuries can be treated with or without ACL reconstruction (ACLR), and more high-quality studies evaluating outcomes after the different treatment courses are needed. The purpose of the present study was to describe and compare 5-year clinical, functional, and physical activity outcomes for patients who...
Article
Osteoarthritis development after ACL reconstruction (ACLR) is not well understood. Investigators have examined associations between knee biomechanical alterations and quantitative MRI (qMRI) variables, reflective of cartilage health, 12‐60 months following ACLR; however, none have done so early after surgery. As part of an exploratory study, forty‐...
Article
Objectives To determine predictors for return to previous level of sports after anterior cruciate ligament reconstruction (ACLR). Design Cross-sectional ; Setting Athletic teams Participants Ninety-one athletes who had ACLR with hamstring-tendon autograft within 1-5 years participated in this study. Athletes indicated their sport participation l...
Article
Full-text available
Background Activity modification is a key component of patellar tendinopathy treatment but there is a lack of evidence guiding activity modification prescription. Use of activity modification in treatment studies has varied widely and the impact of those recommendations has not been directly investigated or compared. The purpose of this study was t...
Article
Full-text available
Background: Gait asymmetries after anterior cruciate ligament reconstruction (ACLR) may lead to radiographic knee osteoarthritis. Slower walking speeds have been associated with biomarkers suggesting cartilage breakdown. The relationship between walking speed and gait symmetry after ACLR is unknown. Hypothesis/purpose: To determine the relations...
Article
Full-text available
Background: After anterior cruciate ligament (ACL) reconstruction (ACLR), biomechanical asymmetries during gait are highly prevalent, persistent, and linked to posttraumatic knee osteoarthritis. Quadriceps strength is an important clinical measure associated with preoperative gait asymmetries and postoperative function and is a primary criterion f...
Article
Full-text available
Cluster analysis of knee abduction moment waveforms may be useful to examine biomechanical data. The aim of this study was to analyze if the knee abduction moment waveform of early peaks, consistent with anterior cruciate ligament injury mechanisms, was associated with foot‐trunk distance, knee kinematics, and heel strike landing posture, all of wh...
Article
Full-text available
Background: Decelerating and cutting are two common movements during which non-contact anterior cruciate ligament (ACL) injuries occur in soccer players. Retrospective video analysis of ACL injuries has demonstrated that players are often in knee valgus at the time of injury. Purpose: To determine whether prospectively measured components of val...
Article
Objective: The objective of this study was to examine the association of quadriceps strength symmetry and surgical status (ACL reconstruction or nonoperative management) with early clinical knee OA 5 years after ACL injury or reconstruction. Methods: 204/300 athletes were analyzed 5 years after ACL injury or reconstruction (ACLR). Quadriceps str...
Article
Full-text available
Background: Anterior cruciate ligament injuries are among the most common knee injuries. Mechanism of injury is classified as contact or non-contact. The majority of anterior cruciate ligament ruptures occur through a non-contact mechanism of injury. Non-contact anterior cruciate ligament ruptures are associated with biomechanical and neuromuscula...
Article
Synopsis: Restoring quadriceps muscle strength is integral to recovery following an anterior cruciate ligament reconstruction. We argue that clinicians should re-evaluate their beliefs about open-chain exercises and measure this important variable to improve outcomes for their patients. J Orthop Sports Phys Ther 2020;50(9):473-475. doi:10.2519/jos...
Article
Full-text available
Objectives Knee injury prevention programs (IPPs) reduce knee and anterior cruciate ligament (ACL) injury rates in female athletes, however, implementation of IPPs is low. The purpose of this study was to identify barriers to implementation of IPPs among collegiate women’s soccer coaches. Design Cross-sectional survey. Methods A custom survey bas...
Preprint
Full-text available
Background: Activity modification is a key component of patellar tendinopathy treatment but there is a lack of evidence guiding activity modification prescription. Use of activity modification in treatment studies has varied widely and the impact of those recommendations has not been directly investigated or compared. The purpose of this study was...
Article
Objectives: (1) To assess prognostic factors for patient-reported outcome measures (PROMs) and physical activity two to ten years after anterior cruciate ligament reconstruction (ACLR) or injury, and (2) to assess differences in prognostic factors between patients treated with ACLR and with rehabilitation alone. Design: Prognosis systematic revi...
Article
Study design: Prospective cohort study. Objectives: Investigate corticospinal, spinal-reflexive excitability and quadriceps strength in athletes after ACL reconstruction (ACLR) and healthy athletes over the course of rehabilitation. Methods: Eighteen athletes with ACLR and eighteen sex, age, and activity matched healthy athletes were tested at...
Article
Objective: To determine if the addition of perturbation training to a secondary injury prevention program reduced the rate of second anterior cruciate ligament (ACL) injuries compared to the prevention program alone. Design: Single-blinded randomized control trial. Methods: Thirty-nine female athletes who intended to return to cutting/pivoting...
Article
Early onset knee osteoarthritis (OA) is associated with gait asymmetries after anterior cruciate ligament reconstruction (ACLR). Women have higher risks of sustaining non‐contact injuries, and are more likely to present with aberrant movement patterns associated with mechanism of injury (MOI). We hypothesized that sex and MOI would influence gait a...
Article
Background The selection of patient-reported outcome measures (PROMs) is essential for obtaining meaningful information to treat a patient, determine a plan of care, and make clinical decisions; however, the process of selecting PROMs for clinical care is difficult, with the need to balance these multiple factors. Variation makes it difficult to co...
Article
Full-text available
Treatment strategies for anterior cruciate ligament (ACL) injuries continue to evolve. Evidence supporting best-practice guidelines for the management of ACL injury is to a large extent based on studies with low-level evidence. An international consensus group of experts was convened to collaboratively advance toward consensus opinions regarding th...
Article
Full-text available
Background A precise and consistent definition of return to sport (RTS) after anterior cruciate ligament (ACL) injury is lacking, and there is controversy surrounding the process of returning patients to sport and their previous activity level. Purpose The aim of the Panther Symposium ACL Injury Return to Sport Consensus Group was to provide a cle...
Presentation
MD Purpose/hypotheses: Patient's satisfaction after anterior cruciate ligament reconstruction (ACLR) is a key component representing the importance of surgical and rehabilitation interventions. 1,2,3,4;5 However, the rate and predictors of patient's satisfaction after ACLR are not well-studied. The purpose of this study was to determine the rate an...
Article
Gait biomechanics after anterior cruciate ligament injury are associated with functional outcomes and the development of post‐traumatic knee osteoarthritis. However, biomechanical outcomes between patients treated non‐operatively compared to operatively are not well understood. The primary purpose of this study was to compare knee joint contact for...
Article
Quadriceps dysfunction persists after anterior cruciate ligament reconstruction (ACLR), yet the etiology remains elusive. Inhibitory and facilitatory intracortical networks (i.e. intracortical excitability) may be involved in quadriceps dysfunction, yet the investigation of these networks early after ACLR is sparse. The purposes of this study were...
Poster
Full-text available
MD Purpose/Hypothesis: The rate of return to pre-injury level of activity and sport (PLAS) after anterior cruciate ligament reconstruction (ACLR) is less than optimal. Reasons that explain the low rate of return to PLAS are not well-determined. Mostly clinical measures related to functional-performance and patient-reported outcomes are used to dete...
Article
Objective To elucidate the relationships between age, return to level I sport (RTS) within the first postoperative year, passing RTS criteria and second anterior cruciate ligament (ACL) injury. Methods In a prospective cohort study, 213 athletes were followed for 2 years after ACL reconstruction to record second ACL injuries. Independent variables...
Article
After ACL injury and reconstruction, biomechanical and neuromuscular control deficits persist and 25% of those who have experienced an ACL injury will experience a second ACL rupture in the 1st year after returning to sports. There remains a need for improved rehabilitation and the ability to detect an individual's risk of secondary ACL rupture. No...
Article
Study design: Retrospective cohort study. Objective: Graft choices for athletes undergoing anterior cruciate ligament reconstruction (ACLR) include bone-patellar tendon-bone (BPTB) and hamstring tendon (HT) autografts, and soft tissue allografts (ALLO). The objective was to assess time to meet clinical milestones by graft type in athletes who co...
Article
Post-traumatic patellofemoral osteoarthritis is prevalent after anterior cruciate ligament reconstruction (ACLR) and early cartilage degradation may be especially common in the femoral trochlear cartilage. Determining the presence of and factors associated with early femoral trochlear cartilage degradation, a precursor to osteoarthritis, is a criti...
Chapter
Preoperative rehabilitation refers to a period of extended rehabilitation prior to surgery that goes beyond basic impairment resolution to improve outcomes after surgery. Successful post-surgical outcomes are influenced by the functional status of the knee joint prior to surgery. Clinicians and researchers from the Delaware-Oslo cohort implement a...
Article
Full-text available
Patellofemoral pain (PFP) is a common musculoskeletal-related condition that is characterized by insidious onset of poorly defined pain, localized to the anterior retropatellar and/or peripatellar region of the knee. The onset of symptoms can be slow or acutely develop with a worsening of pain accompanying lower-limb loading activities (eg, squatti...
Article
Full-text available
Background Outcomes after anterior cruciate ligament reconstruction (ACLR) are not uniformly good and are worse among young female athletes. Developing better rehabilitation and return-to-sport training programs and evaluating their outcomes are essential. Purpose (1) Test the effect of strength, agility, plyometric, and secondary prevention (SAPP...
Article
Background: Partial meniscectomy dramatically increases the risk for post-traumatic, tibiofemoral osteoarthritis after anterior cruciate ligament reconstruction (ACLR). Concomitant medial meniscus surgery influences walking biomechanics (e.g., medial tibiofemoral joint loading) early after ACLR; whether medial meniscus surgery continues to influen...
Article
Objective: To update and expand upon prior Osteoarthritis Research Society International (OARSI) guidelines by developing patient-focused treatment recommendations for individuals with Knee, Hip, and Polyarticular osteoarthritis (OA) that are derived from expert consensus and based on objective review of high-quality meta-analytic data. Methods:...
Article
Full-text available
Objectives Outcomes after anterior cruciate ligament reconstruction (ACLR) are not uniformly acceptable and are worse among young female athletes. Developing better rehabilitation and return-to-sport (RTS) training programs and evaluating their outcomes are essential. The purposes of this study were to: 1) Test the effect of strength, agility, plyo...
Article
Full-text available
Background: Performing physical activities on compliant surfaces alters joints kinematics by decreasing joint motions. However, the effect of administering a training program on a compliant surface on muscle activities after anterior cruciate ligament (ACL) injury is unknown. Hypothesis/purpose: To compare the effects of training on a compliant...
Article
The classification and monitoring of individuals with early knee osteoarthritis (OA) are important considerations for the design and evaluation of therapeutic interventions and require the identification of appropriate outcome measures. Potential outcome domains to assess for early OA include patient-reported outcomes (such as pain, function and qu...
Article
Women after anterior cruciate ligament (ACL) injury and ACL reconstruction (ACLR) are more likely than men to exhibit asymmetric movement patterns, which are associated with post‐traumatic osteoarthritis. We developed the ACL specialized post‐operative return‐to‐sports (ACL‐SPORTS) randomized control trial to test the effect of strength, agility, p...
Article
Background Although unilateral symptoms and unilateral total knee arthroplasty (TKA) are common, many patients have bilateral radiographic osteoarthritis (OA). Because the contralateral (non-operated) limb is often used as a comparison for clinical and biomechanical outcomes, it is important to know if the presence of OA influences movement pattern...
Article
Background:: Some athletes demonstrate excellent dynamic stability after anterior cruciate ligament (ACL) rupture and return to sport without ACL reconstruction (ACLR) (copers). Others demonstrate persistent instability despite rehabilitation (noncopers) and require surgical stabilization. Testing to determine coper classification can identify pot...
Article
Osteoarthritis (OA) progression in the contralateral limb after unilateral total knee arthroplasty (TKA) may be related to altered and asymmetrical movement patterns that overload the contralateral joints. The purpose of this study was to determine if biomechanical factors after unilateral TKA were associated with future contralateral TKA. 158 indi...
Article
Full-text available
Background The risk for knee osteoarthritis (OA) is substantially increased after anterior cruciate ligament (ACL) injury. Tools are needed to identify characteristics of patients after ACL injury who are most at risk for posttraumatic OA. Purpose To determine whether clinical measures of knee function after ACL injury are associated with the deve...