Louise M. Thoma

Hamstring Strength Asymmetry at 3 Years After Anterior Cruciate Ligament Reconstruction Alters Knee Mechanics During Gait and Jogging

Background: Anterior cruciate ligament reconstruction (ACLR) using a hamstring tendon autograft often results in hamstring muscle strength asymmetry. However, the effect of hamstring muscle strength asymmetry on knee mechanics has not been reported. Hypothesis: Participants with hamstring strength asymmetry would demonstrate altered involved limb knee mechanics during walking and jogging compared with those with more symmetric hamstring strength at least 2 years after ACLR with a hamstring tendon autograft. Study Design: Controlled laboratory study. Methods: There were a total of 45 participants at least 2 years after ACLR (22 male, 23 female; mean time after ACLR, 34.6 months). A limb symmetry index (LSI) was calculated for isometric hamstring strength to subdivide the sample into symmetric hamstring (SH) (LSI ≥90%; n = 18) and asymmetric hamstring (AH) (LSI <85%; n = 18) groups. Involved knee kinematic and kinetic data were collected using 3-dimensional motion analysis during gait and jogging. Peak sagittal-, frontal-, and transverse-plane knee angles and sagittal-plane knee moments and knee powers were calculated. Independent-samples t tests and analyses of covariance were used to compare involved knee kinematic and kinetic variables between the groups. Results: There were no differences in sagittal- and frontal-plane knee angles between the groups (P > .05 for all). The AH group demonstrated decreased tibial internal rotation during weight acceptance during gait (P = .01) and increased tibial external rotation during jogging at initial contact (P = .03) and during weight acceptance (P = .02) compared with the SH group. In addition, the AH group demonstrated decreased peak negative knee power during midstance (P = .01) during gait compared with the SH group, after controlling for gait speed, which differed between groups. Conclusion: Participants with hamstring strength asymmetry showed altered involved knee mechanics in the sagittal plane during gait and in the transverse plane during gait and jogging compared with those with more symmetric hamstring strength. Clinical Relevance: Hamstring strength asymmetry is common at 3 years after ACLR with a hamstring tendon autograft and affects involved knee mechanics during gait and jogging. Additional research is warranted to further investigate the longitudinal effect of these alterations on knee function and joint health after ACLR.

Quadriceps Femoris Strength and Sagittal-Plane Knee Biomechanics During Stair Ascent in Individuals With Articular Cartilage Defects in the Knee

CONTEXT Few objective data are available regarding strength and movement patterns in individuals with articular cartilage defects (ACDs) of the knee. OBJECTIVES To test the following hypotheses: (1) The involved limb of individuals with ACDs would demonstrate lower peak knee-flexion angle, peak internal knee-extension moment, and peak vertical ground-reaction force (vGRF) than the contralateral limb and healthy controls. (2) On the involved limb of individuals with ACDs, quadriceps femoris strength would positively correlate with peak knee-flexion angle, peak internal knee-extension moment, and peak vGRF. DESIGN Cross-sectional. SETTING Biomechanics research laboratory. PARTICIPANTS 11 individuals with ACDs in the knee who were eligible for surgical cartilage restoration and 10 healthy controls. METHODS Quadriceps femoris strength was quantified as peak isometric knee-extension torque via an isokinetic dynamometer. Sagittal-plane knee kinematics and kinetics were measured during the stance phase of stair ascent with 3-dimensional motion analysis. MAIN OUTCOME MEASURES Quadriceps strength and knee biomechanics during stair ascent were compared between the involved and contralateral limbs of participants with ACD (paired t tests) and with a control group (independent-samples t tests). Pearson correlations evaluated relationships between strength and stair-ascent biomechanics. RESULTS Lower quadriceps strength and peak internal knee-extension moments were observed in the involved limb than in the contralateral limb (P < .01) and the control group (P < .01). For the involved limb of the ACD group, quadriceps femoris strength was strongly correlated (r = .847) with involved-limb peak internal knee-extension moment and inversely correlated (r = -.635) with contralateral peak vGRF. CONCLUSIONS Individuals with ACDs demonstrated deficits in quadriceps femoris strength with associated alterations in movement patterns during stair ascent. The results of this study are not comprehensive; further research is needed to understand the physiological characteristics, activity performance, and movement quality in this population.

Are Older Adults With Symptomatic Knee Osteoarthritis Less Active Than the General Population? Analysis From the Osteoarthritis Initiative and the National Health and Nutrition Examination Survey

To compare objectively measured physical activity in older adults with symptomatic knee osteoarthritis (OA) with similarly aged adults without osteoarthritis (OA) or knee symptoms from the general population.

Muscle co-contraction during gait in individuals with articular cartilage defects in the knee

Increased muscle co-contraction during gait is common in individuals with knee pathology, and worrisome as it is known to amplify tibiofemoral compressive forces. While knees with articular cartilage defects (ACD) are more vulnerable to compressive forces, muscle co-contraction has never been reported in this population. The purpose of this study was to evaluate the extent to which individuals with ACDs in the knee demonstrate elevated quadriceps to hamstrings muscle co-contraction on the involved limb during gait compared to the uninvolved limb and to healthy controls. We also explored the impact of participant characteristics and knee impairments on co-contraction. Twenty-nine individuals with full-thickness knee ACDs (ACD group) and 19 healthy adults (control group) participated in this study. Participants performed five gait trials at self-selected speed, during which activity of the quadriceps and hamstrings muscles were collected with surface electromyography. Three-dimensional motion capture was used to define phases of gait. Quadriceps strength and self-reported outcomes were also assessed in the same session. There were no differences in quadriceps: hamstrings co-contraction between the ACD and control groups, or between the involved and uninvolved limb for the ACD group. For both ACD and control groups, co-contraction was highest in early stance and lowest in late stance. Quadriceps strength was consistently the strongest predictor of muscle co-contraction in both the ACD and the control groups, with individuals with lower strength demonstrating greater co-contraction. Further study is needed to understand the effect of increased muscle co-contraction on joint compressive forces in the presence of varied quadriceps strength.

Psychological Predictors of Anterior Cruciate Ligament Recovery Outcomes

Despite advancements in surgical techniques and rehabilitation, fewer than half of patients return to their prior level of activity after anterior cruciate ligament (ACL) injury. A growing body of evidence indicates that psychological factors contribute to success or failure in returning to sport. We describe three key psychosocial elements – kinesiophobia, social considerations, and individual personality traits – that can be predictive of return to sport. We review the current literature on each topic and describe how each has been shown to be predictive of return to sport (or lack of return to sport) after ACL reconstruction. Finally, we will discuss the possibility that addressing psychological factors in ACL reconstruction may potentially improve return to sport rates.

A Physical Therapist–Administered Physical Activity Intervention After Total Knee Replacement: Protocol for a Randomized Controlled Trial

Background. The definitive treatment for knee osteoarthritis is a total knee replacement, which results in a clinically meaningful improvement in pain and physical function. However, evidence suggests that physical activity (PA) remains unchanged after total knee replacement (TKR). Objective. The objective of this study is to investigate the efficacy, fidelity, and safety of a physical therapist‐administered PA intervention for people after TKR. Design. This study will be a randomized controlled trial. Setting. The setting is an outpatient physical therapy clinic. Participants. The participants are 125 individuals who are over the age of 45 and are seeking outpatient physical therapy following a unilateral TKR. Intervention. In addition to standardized physical therapy after TKR, the intervention group will receive, during physical therapy, a weekly PA intervention that includes a wearable activity tracking device, individualized step goals, and face‐to‐face feedback provided by a physical therapist. Control. The control group will receive standardized physical therapy alone after TKR. Measurements. The efficacy of the intervention will be measured as minutes per week spent in moderate to vigorous PA at enrollment, at discharge, and at 6 months and 12 months after discharge from physical therapy. The fidelity and safety of the intervention will be assessed throughout the study. Limitations. Participants will not be masked, PA data will be collected after randomization, and the trial will be conducted at a single site. Conclusions. The goal of this randomized controlled trial is to increase PA after TKR. A protocol for investigating the efficacy, fidelity, and safety of a physical therapist‐administered PA intervention for people after TKR is presented. The findings will be used to support a large multisite clinical trial to test the effectiveness, implementation, and cost of this intervention.

Minimum performance on clinical tests of physical function to predict walking 6000 steps/day in knee osteoarthritis: An observational study

Evidence of physical function difficulties, such as difficulty rising from a chair, may limit daily walking for people with knee osteoarthritis (OA). The purpose of this study was to identify minimum performance thresholds on clinical tests of physical function predictive to walking ≥6,000 steps/day. This benchmark is known to discriminate people with knee OA who develop functional limitation over time from those who do not.

High Kinesiophobia and Pain Catastrophizing in People with Articular Cartilage Defects in the Knee

Objectives: Psychosocial factors, including kinesiophobia and pain catastrophizing, are increasingly recognized for the role they play in knee function and quality of life for people with anterior cruciate ligament reconstruction (ACLR), knee osteoarthritis (OA), and total knee arthroplasties (TKA). People with articular cartilage defects in the knee have impaired function and poor quality of life, however the extent to which they present with kinesiophobia and pain catastrophizing is not known. The purpose of this study is to compare kinesiophobia, i.e. fear of movement-related pain/reinjury, and pain catastrophizing of people with articular cartilage defects (ACD) in the knee to healthy controls. Methods: Thirty-five individuals (19M:16F, Age mean ± 95%CI 29.8 ± 2.8 years old, BMI 28.1 ± 1.44) seeking surgical consultation for an ACD in the knee confirmed with 3.0T MRI and 18 controls (9M:9F, Age 29.8 ± 3.0 years old, BMI 24.9 ± 1.3) without history of knee injury participated in the study. Exclusion criteria included; age >55 years, BMI >35kg/m2, recent surgery, current low back pain or unrelated lower extremity pain, and history of spine surgery or neurological injury and pathology. Kinesiophobia for all 53 subjects was measured with the Tampa Scale of Kinesiophobia (TSK). The TSK was scored using the original 17-item (TSK-17, Min 17 - Max 68) and modified 11-item (TSK-11, Min 11 - Max 44) scoring systems as both have been commonly used in the literature. Pain catastrophizing was measured with the Pain Catastrophizing Scale (PCS, Min 0 - Max 52). Higher scores on these measures indicate greater kinesiophobia and pain catastrophizing. Independent t-tests were used to compare the ACD group to the healthy controls (α=0.05). Mean TSK and PCS scores (± 95% CI) were plotted alongside values published in samples with other knee pathologies for reference. Results: Participants with ACDs reported higher kinesiophobia (TSK-17 mean score ± 95%CI [range]: ACD 40.9 ± 1.7 [29-53], Healthy Control 29.9 ± 1.3 [26-35], p<0.001; TSK-11 score: ACD 27.0 ± 1.2[16-34], Healthy Control 15.8 ± 1.2 [11-20], p<0.001) and higher pain catastrophizing (PCS score: ACD 12.7 ± 3.5 [0-42], Healthy Control 4.0 ± 2.6 [0-14], p<0.001) than age-matched healthy controls. Greater kinesiophobia and pain catastrophizing were also observed in people with ACDs compared to values published in people after ACLR, people with knee OA, and similar to people with severe OA preparing for TKA (Figure 1). Conclusion: This is the first study to our knowledge to evaluate psychosocial factors in people with ACDs of the knee. Kinesiophobia and pain catastrophizing in people with knee ACDs were similar to people with severe knee OA preparing for TKA, and higher than healthy controls and people before and after ACLR. While higher kinesiophobia and pain catastrophizing are consistently associated with worse function and quality of life in these populations, understanding the relationship to outcomes and prognosis in people with knee ACDs remains unknown and is a target of our ongoing work.