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 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.

scholarly journals Iliotibial Band Autograft Provides the Fastest Recovery of Knee Extensor Mechanism Function in Pediatric Anterior Cruciate Ligament Reconstruction

2021 ◽  
Vol 18 (14) ◽  
pp. 7492
Author(s):  
Tishya L. Wren ◽  
Veronica Beltran ◽  
Mia J. Katzel ◽  
Adriana S. Conrad-Forrest ◽  
Curtis D. VandenBerg
Keyword(s):  
Knee Flexion ◽  
Ligament Reconstruction ◽  
Cruciate Ligament ◽  
Knee Extensor ◽  
Extensor Mechanism ◽  
Iliotibial Band ◽  
Cruciate Ligament Reconstruction ◽  
Mechanism Function ◽  
Anterior Cruciate ◽  
Knee Extensor Mechanism

Iliotibial band autograft is an increasingly popular option for pediatric anterior cruciate ligament reconstruction (ACLR). The purpose of this study was to compare recovery of knee extensor mechanism function among pediatric patients who underwent ACLR using iliotibial band (IT), hamstring tendon (HT), quadriceps tendon (QT), and patellar tendon (PT) autografts. One hundred forty-five pediatric athletes (76 female; age 15.0, range 7–21 years) with recent (3–18 months) unilateral ACLR performed drop-jump landing and 45° cutting with 3D motion capture. Knee extensor mechanism function (maximum knee flexion angle, maximum internal knee extensor moment, energy absorption at knee) during the loading phase (foot contact to peak knee flexion) was compared among graft types (20 IT, 29 HT, 39 QT, 57 PT) and sides (ACLR or contralateral) using linear mixed models with sex, age, and time since surgery as covariates. Overall, knee flexion was significantly lower on the operated vs. contralateral side for HT, QT, and PT during both tasks (p < 0.03). All graft types exhibited lower knee extensor moments and energy absorption on the operated side during both movements (p ≤ 0.001). Kinetic asymmetry was significantly lower for IT compared with QT and PT during both movements (p ≤ 0.005), and similar patterns were observed for HT vs. QT and PT (p ≤ 0.07). Asymmetry was similar between IT and HT and between QT and PT. This study found that knee extensor mechanism function recovers fastest in pediatric ACLR patients with IT autografts, followed by HT, in comparison to QT and PT, suggesting that IT is a viable option for returning young athletes to play after ACLR.

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 Vancomycin presoaking of hamstring grafts removes the risk of infection in primary anterior cruciate ligament reconstruction

2018 ◽  
Vol 6 (12_suppl5) ◽  
pp. 2325967118S0018
Author(s):  
Francisco Figueroa ◽  
David Figueroa ◽  
Rafael Calvo ◽  
Alex Vaisman ◽  
Mario López ◽  
...  
Keyword(s):  
Anterior Cruciate Ligament ◽  
Septic Arthritis ◽  
Acl Reconstruction ◽  
Cruciate Ligament ◽  
Hamstring Autograft ◽  
Exact Test ◽  
Previous Period ◽  
Anterior Cruciate ◽  
Primary Acl Reconstruction ◽  
Hamstring Grafts

Background: Several strategies have been studied to decrease the rate of infection after hamstring autograft anterior cruciate ligament (ACL) reconstruction. Our group started presoaking grafts with Vancomycin in November 2015 to decrease this risk. Purpose: The objective of the study is to compare the success of this protocol against the immediate previous period in which we did not use the protocol. Study design: Retrospective cohort. Level III. Methods: Consecutive periods were studied: April 2013-October 2015 (pre Vancomycin protocol) and November 2015- May 2018 (Vancomycin protocol). All patients that underwent a hamstring autograft primary ACL reconstruction during the periods studied were included. The final outcome was the presence of postoperative septic arthritis in both groups. Diagnosis of septic arthritis was made using the clinical picture plus cytological analysis of a joint aspiration (cell count > 50.000/uL + > 90% neutrophils) Statistical analysis was made using the Fisher’s exact test. Significance was set in p < 0.05. Results: 490 patients were included in the study, 230 in the pre Vancomycin protocol an 260 in the Vancomycin protocol. 4 postoperative septic arthritis were noted in the pre Vancomycin protocol (1.7%) while no septic arthritis was noted in the post Vancomycin protocol patients during the period studied. (p < 0.05) The 4 postoperative infections were presented at an average 21.7 days (range 16-25). Staphylococcus epidermidis was isolated in 2 of the cases, and in the other 2 no organism was isolated. Conclusion: Vancomycin presoaking of hamstring autografts in primary ACL reconstruction eliminated the risk of postoperative septic arthritis during the studied period compared to the immediate previous period, where no Vancomycin presoaking was used.

scholarly journals Factors Associated With Psychological Readiness to Return to Sports With Cutting, Pivoting, and Jump-Landings After Primary ACL Reconstruction

2020 ◽  
Vol 8 (11) ◽  
pp. 232596712096448
Author(s):  
Junya Aizawa ◽  
Kenji Hirohata ◽  
Shunsuke Ohji ◽  
Takehiro Ohmi ◽  
Hideyuki Koga ◽  
...  
Keyword(s):  
Anterior Cruciate Ligament ◽  
Regression Analysis ◽  
Acl Reconstruction ◽  
Cruciate Ligament ◽  
Return To Play ◽  
Return To Sports ◽  
Factors Associated ◽  
Anterior Cruciate ◽  
Primary Acl Reconstruction ◽  
Jump Landings

Background: High psychological readiness is an important element for returning to sports after anterior cruciate ligament (ACL) reconstruction. Identifying factors that contribute to psychological readiness is essential for planning interventions to return to play. No studies have used multivariate analysis to clarify factors associated with psychological readiness to return to specific sports. Hypothesis: To identify factors that contribute to an athlete’s psychological readiness to return after ACL reconstruction to sports that require cutting, pivoting, and jump-landings. Study Design: Cross-sectional study; Level of evidence, 3. Methods: Study participants were athletes who before injury had participated in sports with limited contact that required cutting, pivoting, and jump-landings (basketball, soccer, futsal, volleyball, badminton, tennis, and frisbee) and hoped to return to the same sport after reconstruction. Psychological readiness was measured using the Anterior Cruciate Ligament–Return to Sport After Injury Scale (ACL-RSI) in athletes more than 6 months after primary ACL reconstruction. To clarify factors associated with the ACL-RSI, univariate regression analysis and multivariate regression analysis were performed using the following independent variables: age, sex, body mass index, time from injury to reconstruction, time from reconstruction to testing, meniscal surgery, modified Tegner activity scale before injury, kinesiophobia, limb symmetry index of knee strength, limb symmetry indices of single-leg hop (SLH) distances, and subjective running ability. Results: Higher subjective running ability, a lower kinesiophobia score, and greater limb symmetry in the lateral SLH were positively associated with psychological readiness. Conclusion: The psychological readiness of athletes aiming to return after ACL reconstruction to limited-contact sports that require cutting, pivoting, and jump-landings was affected by subjective running ability, kinesiophobia, and asymmetry of lateral SLH distance. This information may be useful in planning appropriate interventions and thereby increasing the likelihood of an athlete’s returning to such sports.

Incidence and Risk Factors of Subsequent Meniscal Surgery After Successful Anterior Cruciate Ligament Reconstruction: A Retrospective Study With a Minimum 2-Year Follow-up

2020 ◽  
Vol 48 (14) ◽  
pp. 3525-3533
Author(s):  
Yuka Kimura ◽  
Eiji Sasaki ◽  
Yuji Yamamoto ◽  
Shizuka Sasaki ◽  
Eiichi Tsuda ◽  
...  
Keyword(s):  
Risk Factors ◽  
Anterior Cruciate Ligament ◽  
Acl Reconstruction ◽  
Cruciate Ligament ◽  
Anterior Laxity ◽  
Meniscal Surgery ◽  
Anterior Cruciate ◽  
Femoral Tunnel Drilling ◽  
Primary Acl Reconstruction

Background: One of the goals of anterior cruciate ligament (ACL) reconstruction is a meniscal protective effect on the knee. Despite the advancement of ACL reconstruction techniques, subsequent meniscal tears after ACL reconstruction remain a problem, and the risk factors for recurring lesions are still unclear. Purpose: To investigate the incidence of subsequent meniscal surgery after primary ACL reconstruction without revision ACL surgery and to determine the risk factors associated with this reoperation. Study Design: Case series; Level of evidence, 4. Methods: Overall, 518 patients who underwent primary ACL reconstruction between 2004 and 2012 at one instution participated in this study. Data on body mass index, graft type and femoral tunnel-drilling technique of ACL reconstruction, and location and type of meniscal injury and its treatment at ACL reconstruction were collected from medical records. Clinical outcomes were investigated, including side-to-side difference of anterior laxity, pivot-shift grade, and subsequent meniscal surgery without ACL insufficiency (at minimum 2-year follow-up). Results: The prevalence of tears to the medial meniscus (MM) at the primary ACL reconstruction was 43.6% (226/518), 140 of which were repaired; on the contrary, tears of the lateral meniscus (LM) had a prevalence of 55.8% (289/518), 42 of which were repaired. At a mean 30.3 months (range, 8-124 months) after ACL reconstruction, 20 patients (3.9%; 14 MM tears, 3 LM tears, 3 MM + LM tears) required meniscal surgery without ACL reinjury or recurrence of instability. Of these, 14 MMs and 3 LMs had been repaired at primary ACL reconstruction. The failure rates of repaired MM and LM were 10.0% (14/140) and 7.1% (3/42), respectively. The failure rate of MM repair using the all-inside technique (6/36) was significantly higher compared with no treatment, inside-out repair, or partial resection ( P = .045). In multiple regression analysis, the presence of MM injury at the time of ACL reconstruction (odds ratio [OR], 7.81; P = .003), the side-to-side difference of postoperative anterior tibial translation (OR, 1.91; P = .032), and follow-up period after ACL reconstruction (OR, 1.02; P = .003) were risk factors of subsequent meniscal surgery after ACL reconstruction. Conclusion: Incidence of subsequent meniscal surgery after successful ACL reconstruction was <5%. Presence of MM tear at the time of ACL reconsturuction, small amount of increased anterior laxity, and long-term period after ACL reconstruction were predictive of subsequent meniscal surgery.

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