scholarly journals Conditioning Brain Responses to Improve Quadriceps Function in an Individual With Anterior Cruciate Ligament Reconstruction

2019 ◽  
Vol 11 (4) ◽  
pp. 306-315 ◽  
Author(s):  
Chandramouli Krishnan ◽  
Edward P. Washabaugh ◽  
Aviroop Dutt-Mazumder ◽  
Scott R. Brown ◽  
Edward M. Wojtys ◽  
...  
Keyword(s):  
Acl Reconstruction ◽  
Operant Conditioning ◽  
Muscle Activation ◽  
Cruciate Ligament ◽  
Knee Extensor ◽  
Quadriceps Muscle ◽  
Corticospinal Excitability ◽  
Knee Extensor Strength ◽  
Anterior Cruciate ◽  
Quadriceps Function

Background: Persistent quadriceps weakness and activation failure are common in individuals with anterior cruciate ligament (ACL) reconstruction. A growing body of evidence indicates that this chronic quadriceps dysfunction could be partly mediated due to reduced corticospinal excitability. However, current rehabilitation approaches do not directly target corticospinal deficits, which may be critical for restoring optimal clinical outcomes after the surgery. This case study tested the feasibility of operant conditioning of torque responses evoked by transcranial magnetic stimulation (TMS) to improve quadriceps function after ACL reconstruction. Hypothesis: Operant conditioning of motor evoked torque responses would improve quadriceps strength, voluntary activation, and corticospinal excitability. Study Design: Case study and research report. Level of Evidence: Level 5. Methods: A 24-year-old male with an ACL reconstruction (6 months postsurgery) trained for 20 sessions (2-3 times per week for 8 weeks) to increase his TMS-induced motor evoked torque response (MEP torque) of the quadriceps muscles using operant conditioning principles. Knee extensor strength, voluntary quadriceps muscle activation, and quadriceps corticospinal excitability were evaluated at 3 time points: preintervention (pre), 4 weeks (mid), and immediately after the intervention (post). Results: The participant was able to successfully condition (ie, increase) the quadriceps MEP torque after 1 training session, and the conditioned MEP torque gradually increased over the course of 20 training sessions to reach about 500% of the initial value at the end of training. The participant’s control MEP torque values and corticospinal excitability, which were measured outside of the conditioning paradigm, also increased with training. These changes were paralleled by improvements in knee extensor strength and voluntary quadriceps muscle activation. Conclusion: This study shows that operant conditioning of MEP torque is a feasible approach to improving quadriceps corticospinal excitability and quadriceps function after ACL reconstruction and encourages further testing in a larger cohort of ACL-reconstructed individuals. Clinical Relevance: Operant conditioning may serve as a potential therapeutic adjuvant for ACL rehabilitation.

Single-Leg Squat Performance and Its Relationship to Extensor Mechanism Strength After Anterior Cruciate Ligament Reconstruction

2019 ◽  
Vol 47 (14) ◽  
pp. 3423-3428 ◽  
Author(s):  
Lachlan M. Batty ◽  
Julian A. Feller ◽  
Taylor Hartwig ◽  
Brian M. Devitt ◽  
Kate E. Webster
Keyword(s):  
Acl Reconstruction ◽  
Cruciate Ligament ◽  
Knee Extensor ◽  
Extensor Mechanism ◽  
Flexion Angle ◽  
Maximum Flexion ◽  
Knee Extensor Strength ◽  
Maximum Flexion Angle ◽  
Anterior Cruciate ◽  
Primary Acl Reconstruction

Background: Performance in strength and functional testing is important when considering return to sport after anterior cruciate ligament (ACL) reconstruction. Both knee extensor strength and the single-leg squat (SLS) have been used in this context. Purpose: To evaluate the relationship between knee extensor strength and SLS performance after primary ACL reconstruction. Study Design: Cohort study (Diagnosis); Level of evidence, 3. Methods: A prospective cohort of 100 patients was assessed 6 and 12 months after primary ACL reconstruction with a hamstring tendon autograft. Knee extensor peak torque was measured. Three sequential SLSs were performed, and the maximum flexion angle identified from frame-by-frame video analysis was used as the measure of squat performance. A limb symmetry index (LSI) was calculated and satisfactory performance defined as ≥90%. Results: Extensor mechanism strength deficits were seen in 75% of patients at 6 months and 57% at 12 months postoperatively. Mean extensor mechanism strength showed a large improvement between 6 and 12 months (123.6 vs 147.8 N·m, respectively; P < .001; Cohen d = 1.10), and while there was also a statistically significant improvement in the mean maximum flexion angle, the change was small (66.1° vs 68.1°, respectively; P = .011; Cohen d = 0.26). There was a weak positive correlation between knee extensor strength and the SLS maximum flexion angle at 6 months ( r = 0.342; P < .001) and 12 months ( r = 0.245; P = .014). An SLS LSI <90% was 80% specific and 35% sensitive for extensor mechanism weakness at 6 months and 79% specific and 18% sensitive at 12 months. Conclusion: Extensor mechanism strength deficits are common after ACL reconstruction but reduce between 6 and 12 months. The SLS maximum flexion angle has a weak linear relationship to knee extensor strength. SLS performance has high specificity but low sensitivity in identifying extensor mechanism strength deficits. The SLS maximum flexion angle is therefore a suboptimal surrogate test to identify extensor mechanism strength deficits as diagnosed by isokinetic dynamometric testing. However, unsatisfactory SLS performance indicates a very high chance of underlying extensor mechanism weakness.

Knee Extensor Mechanism Strength and Its Relationship to Patellofemoral Kinematics in Individuals With Arthrofibrosis Within 6 Months After Anterior Cruciate Ligament Reconstruction

2021 ◽  
pp. 1-6
Author(s):  
Ling Zhang ◽  
Shao-bai Wang ◽  
Shuai Fan ◽  
Jiling Ye ◽  
Bin Cai
Keyword(s):  
Anterior Cruciate Ligament ◽  
Acl Reconstruction ◽  
Cruciate Ligament ◽  
Knee Extensor ◽  
Extensor Mechanism ◽  
Knee Extensor Strength ◽  
Anterior Cruciate ◽  
Patellofemoral Kinematics ◽  
Patellar Mobility ◽  
Knee Extensor Mechanism

Context: Performance in strength and assessment of patellar tracking is important for patients with arthrofibrosis after anterior cruciate ligament (ACL) reconstruction. Objective: The study was to examine the difference of patellofemoral kinematics between the affected and the contralateral limb and to evaluate the relationship between knee extensor strength and patellofemoral kinematics in patients with arthrofibrosis after ACL reconstruction. Design: Cohort study (diagnosis); level of evidence, 3. Setting: Laboratory. Patients: A prospective cohort of 20 patients with arthrofibrosis after ACL reconstruction was recruited. Interventions: A total of 20 patients who underwent arthroscopic reconstruction of the double-bundle ACL with a hamstring tendon autograft received standardized patellofemoral kinematics testing and knee extensor strength testing within 6 months after primary ACL reconstruction. Computed tomography and dual fluoroscopic imaging were used to evaluate in vivo patellofemoral kinematics of affected and contralateral knees during a lunge task. Knee extensor mechanism strength was measured using a handheld dynamometer. Main Outcome Measures: A limb symmetry index of knee strength and patellar mobility was calculated and satisfactory performance defined as ≥90%. Results: There was a statistically significant decrease in the range of patellar inferior shift (P = .020; d = 0.81), flexion (P = .026; d = 0.95), lateral tilt (P = .001; d = 1.04), and lateral rotation (P < .001; d = 0.89) in the affected knee compared with the contralateral knee from 15° to 75° of knee flexion. There was a strong positive linear correlation between knee extensor strength and patellar inferior shift (r = .747; P = .008). A knee extensor strength limb symmetry index <90% was 89% sensitive and 9% specific for limited patellar inferior shift. Conclusions: Patients with arthrofibrosis after ACL reconstruction presented decreased patellar mobility in the arthrofibrotic knee compared with the contralateral knee. The strong correlation between knee extensor strength and patellar inferior shift of the arthrofibrotic knee demonstrates the importance of knee extensor strength in the diagnosis and treatment of patients with knee arthrofibrosis. The knee extensor mechanism strength has high sensitivity but low specificity in identifying a decrease in patellar inferior shift in patients with arthrofibrosis after ACL reconstruction.

scholarly journals No Relationship Between Preoperative and Early Postoperative Strength After ACL Reconstruction

2020 ◽  
Vol 29 (5) ◽  
pp. 583-587
Author(s):  
Pier Paolo Mariani ◽  
Luca Laudani ◽  
Jacopo E. Rocchi ◽  
Arrigo Giombini ◽  
Andrea Macaluso
Keyword(s):  
Acl Reconstruction ◽  
Cruciate Ligament ◽  
Knee Extensor ◽  
Quadriceps Strength ◽  
Maximal Voluntary Isometric Contraction ◽  
Extensor Muscles ◽  
Flexor Muscles ◽  
Anterior Cruciate ◽  
Tendon Autograft ◽  
Knee Extensor Muscles

Context: All rehabilitative programs before anterior cruciate ligament (ACL) reconstructive surgery, which are focused on recovery of proprioception and muscular strength, are defined as prehabilitation. While it has shown that prehabilitation positively affects the overall outcome after ACL reconstruction, it is still controversial whether preoperatively enhancing quadriceps strength has some beneficial effect on postoperative strength, mainly during the first period. Objective: To determine whether there is any relationship between preoperative and early postoperative quadriceps strength. Design: Case control. Setting: University research laboratory. Participants: Fifty-nine males (18–33 y; age: 23.69 [0.71] y) who underwent ACL reconstruction with patellar-tendon autograft were examined the day before surgery, and at 60 and 90 days after surgery. Main Outcome Measures: The limb symmetry index (LSI) was quantified for maximal voluntary isometric contraction of the knee extensor muscles and of the knee flexor muscles at 90° joint angle. A k-means analysis was performed on either quadriceps or hamstrings LSI before surgery to classify the patients in high and low preoperative LSI clusters. Differences in postoperative LSI were then evaluated between the high and low preoperative LSI clusters. Results: Following surgery, there were no differences in the quadriceps LSI between patients with high and low preoperative quadriceps LSI. Sixty days after surgery, the hamstrings LSI was higher in patients with high than low preoperative hamstrings LSI (84.0 [13.0]% vs 75.4 [15.9]%; P < .05). Conclusions: Findings suggest that quadriceps strength deficit is related to the ACL injury and increases further after the reconstruction without any correlation between the preoperative and postoperative values. Therefore, it appears that there is no need to delay surgery in order to increase the preoperative quadriceps strength before surgery.

scholarly journals Quadriceps Recovery After Anterior Cruciate Ligament Reconstruction With Quadriceps Tendon Versus Patellar Tendon Autografts

2019 ◽  
Vol 7 (4) ◽  
pp. 232596711983978 ◽  
Author(s):  
Jennifer L. Hunnicutt ◽  
Chris M. Gregory ◽  
Michelle M. McLeod ◽  
Shane K. Woolf ◽  
Russell W. Chapin ◽  
...  
Keyword(s):  
Functional Outcomes ◽  
Ligament Reconstruction ◽  
Cruciate Ligament ◽  
Knee Extensor ◽  
Quadriceps Tendon ◽  
Step Length ◽  
Quadriceps Muscle ◽  
Muscle Size ◽  
Cross Sectional ◽  
Anterior Cruciate

Background: Quadriceps tendon (QT) autografts are being increasingly used for anterior cruciate ligament reconstruction (ACLR). A paucity of studies exist that compare QT autografts with alternative graft options. Additionally, concerns exist regarding quadriceps recovery after graft harvest insult to the quadriceps muscle-tendon unit. Purpose/Hypothesis: The purpose of this study was to compare quadriceps recovery and functional outcomes in patients with QT versus bone–patellar tendon–bone (BPTB) autografts. The hypothesis was that those with QT autografts would demonstrate superior outcomes. Study Design: Cohort study; Level of evidence, 3. Methods: Active patients with a history of primary, unilateral ACLR with soft tissue QT or BPTB autografts participated. Quadriceps recovery was quantified using variables of strength, muscle size, and activation. Knee extensor isometric and isokinetic strength was measured bilaterally with an isokinetic dynamometer and normalized to body weight. Quadriceps activation was measured with the superimposed burst technique. The maximal cross-sectional area of each quadriceps muscle was measured bilaterally using magnetic resonance imaging. Assessors of muscle size were blinded to the graft type and side of ACLR. Functional tests included hop tests and step length symmetry during walking, measured via spatiotemporal gait analysis. Self-reported function was determined with the International Knee Documentation Committee (IKDC) questionnaire. Neuromuscular and functional outcomes were expressed as limb symmetry indices (LSIs: [surgical limb/nonsurgical limb]*100%). Wilcoxon rank-sum tests were used to compare the LSIs and IKDC scores between groups. Results: There were 30 study participants (19 male, 11 female; median age, 22 years [range, 14-41 years]; median time since surgery, 8 months [range, 6-23 months]), with 15 patients in each group. There were no significant between-group differences in demographic variables or outcomes. LSIs were not significantly different between the QT versus BPTB group, respectively: knee extensor isokinetic strength at 60 deg/s (median, 70 [range, 41-120] vs 68 [range, 37-83]; P = .285), activation (median, 95 [range, 85-111] vs 92 [range, 82-105]; P = .148), cross-sectional area of the vastus medialis (median, 79 [range, 62-104] vs 77 [range, 62-95]; P = .425), single-leg hop test (median, 88 [range, 35-114] vs 77 [range, 49-100]; P = .156), and step length symmetry (median, 99 [range, 93-104] vs 98 [range, 92-103]; P = .653). The median IKDC scores between the QT and BPTB groups were also not significantly different: 82 (range, 67-94) versus 83 (range, 54-94); respectively ( P = .683). Conclusion: Patients with QT autografts demonstrated similar short-term quadriceps recovery and postsurgical outcomes compared with patients with BPTB autografts.

scholarly journals Quadriceps Function and Patient-Reported Outcomes After Anterior Cruciate Ligament Reconstruction in Patients With or Without Knee Osteoarthritis

2018 ◽  
Vol 53 (10) ◽  
pp. 965-975 ◽  
Author(s):  
Grant E. Norte ◽  
Jay Hertel ◽  
Susan A Saliba ◽  
David R. Diduch ◽  
Joseph M. Hart
Keyword(s):  
Knee Osteoarthritis ◽  
Patient Reported Outcomes ◽  
Cruciate Ligament ◽  
Knee Extensor ◽  
Activity Level ◽  
Koos Score ◽  
Patient Reported ◽  
Active Motor ◽  
Anterior Cruciate ◽  
Quadriceps Function

Context Relationships between quadriceps function and patient-reported outcomes after anterior cruciate ligament reconstruction (ACLR) are variable and may be confounded by including patients at widely different time points after surgery. Understanding these relationships during the clinically relevant phases of recovery may improve our knowledge of specific factors that influence clinical outcomes. Objective To identify the relationships between quadriceps function and patient-reported outcomes in patients &lt;2 years (early) and &gt;2 years (late) after ACLR, including those with posttraumatic knee osteoarthritis. Design Cross-sectional study. Setting Laboratory. Patients or Other Participants A total of 72 patients after ACLR: early (n = 34, time from surgery = 9.0 ± 4.3 months), late (n = 30, time from surgery = 70.5 ± 41.6 months), or osteoarthritis (n = 8, time from surgery = 115.9 ± 110.0 months). Main Outcome Measure(s) The total Knee Injury and Osteoarthritis Outcome Score (KOOS) and Veterans RAND 12-Item Health Survey (VR-12) were used to quantify knee function and global health. Predictors of patient-reported outcomes were involved-limb and symmetry indices of quadriceps function (isokinetic strength [peak torque, total work, average power], maximum voluntary isometric contraction torque, fatigue index, central activation ratio, Hoffmann reflex, active motor threshold) and demographics (age, activity level, pain, kinesiophobia, time since surgery). Multiple linear regression analyses were used to predict KOOS and VR-12 scores in each group. Results In the early patients, knee-extensor work, active motor threshold symmetry, pain, and activity level explained 67.8% of the variance in the KOOS score (P &lt; .001); knee-extensor work, activity level, and pain explained 53.0% of the variance in the VR-12 score (P &lt; .001). In the late patients, age and isokinetic torque symmetry explained 28.9% of the variance in the KOOS score (P = .004). In the osteoarthritis patients, kinesiophobia and isokinetic torque explained 77.8% of the variance in the KOOS score (P = .010); activity level explained 86.4% of the variance in the VR-12 score (P = .001). Conclusions Factors of muscle function and demographics that explain patient-reported outcomes were different in patients early and late after ACLR and in those with knee osteoarthritis.

scholarly journals Quadriceps Function After Exercise in Patients with Anterior Cruciate Ligament–Reconstructed Knees Wearing Knee Braces

2011 ◽  
Vol 46 (6) ◽  
pp. 615-620 ◽  
Author(s):  
Alexis G. Davis ◽  
Brian G. Pietrosimone ◽  
Christopher D. Ingersoll ◽  
Kelli Pugh ◽  
Joseph M. Hart
Keyword(s):  
Anterior Cruciate Ligament ◽  
Aerobic Exercise ◽  
Muscle Activation ◽  
Cruciate Ligament ◽  
Knee Brace ◽  
Maximal Voluntary Isometric Contraction ◽  
Before And After ◽  
Knee Braces ◽  
Anterior Cruciate ◽  
Quadriceps Function

Context: Knee braces and neoprene sleeves are commonly worn by people with anterior cruciate ligament reconstructions (ACLRs) during athletic activity. How knee braces and sleeves affect muscle activation in people with ACLRs is unclear.Purpose: To determine the effects of knee braces and neoprene knee sleeves on the quadriceps central activation ratio (CAR) before and after aerobic exercise in people with ACLRs.Design: Crossover study.Patients or Other Participants: Fourteen people with a history of ACLR (9 women, 5 men: age = 23.61 ± 4.44 years, height = 174.09 ± 9.82 cm, mass = 75.35 ± 17.48 kg, months since ACLR = 40.62 ± 20.41).Intervention(s): During each of 3 sessions, participants performed a standardized aerobic exercise protocol on a treadmill. The independent variables were condition (brace, sleeve, or control) and time (baseline, pre-exercise with brace, postexercise with brace, postexercise without brace).Main Outcome Measure(s): Normalized torque measured during a maximal voluntary isometric contraction (TMVIC) and CAR were measured by a blinded assessor using the superimposed burst technique. The CAR was expressed as a percentage of full muscle activation. The quadriceps CAR and TMVIC were measured 4 times during each session: baseline, pre-exercise with brace, postexercise with brace, and postexercise without brace.Results: Immediately after the application of the knee brace, TMVIC decreased (P = .01), but no differences between bracing conditions were observed. We noted reduced TMVIC and CAR (P &lt; .001) after exercise, both with and without the brace. No differences were seen between bracing conditions after aerobic exercise.Conclusions: The decrease in TMVIC immediately after brace application was not accompanied by differences between bracing conditions. Wearing a knee brace or neoprene sleeve did not seem to affect the deterioration of quadriceps function after aerobic exercise.

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