Arthrogenic muscle inhibition after ACL reconstruction: a scoping review of the efficacy of interventions

Objective: To determine whether reported therapeutic interventions for arthrogenic muscle inhibition (AMI) in patients with ACL injuries, following ACL reconstruction, or in laboratory studies of AMI, are effective in improving quadriceps activation failure when compared with standard therapy in control groups. Design: A scoping review of the efficacy of interventions was conducted in accordance with the methodological framework of Arksey and O'Malley and the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Search terms included 'arthrogenic muscle inhibition', 'quadriceps activation following knee injuries', 'anterior cruciate' or 'knee’ combined with 'quadriceps activation', 'quadriceps inhibition', 'corticomotor', 'arthrogenic', 'brain activation' and 'neuroplasticity'. Articles were evaluated for risk of bias using the PEDro (Physiotherapy Evidence Database) criteria. The overall quality of evidence for each intervention was assessed using Grading of Recommendations Assessment, Development and Evaluation (GRADE). Data sources: PubMed, EMBASE and Cumulative Index to Nursing and Allied Health Literature databases. Eligibility criteria for selecting studies: Isolated case reports and articles reporting outcomes in patients with chronic disease or major trauma were excluded. All other original research articles were included. Results: 780 potential articles were identified. 20 met the inclusion criteria. These studies provided a moderate quality of evidence to support the efficacy of cryotherapy and physical exercises in the management of AMI. There was low-quality evidence for efficacy of neuromuscular electrical stimulation and transcutaneous electrical nerve stimulation, and very low-quality evidence for efficacy of ultrasound and vibration. Conclusions: This scoping review demonstrated moderate-quality evidence for the efficacy of cryotherapy and physical exercises in improving quadriceps activation failure after ACL injury and reconstruction. These therapeutic modalities are therefore recommended in the management of AMI

Anterolateral ligament reconstruction protects the repaired medial meniscus: a comparative study of 383 anterior cruciate ligament reconstructions from the SANTI study group with a minimum follow-up of 2 years

Background: The prevalence of osteoarthritis after successful meniscal repair is significantly less than that after failed meniscal repair. Study Design: Cohort study; Level of evidence, 3. Purpose: The aim of this study was to determine whether the addition of anterolateral ligament reconstruction (ALLR) confers a protective effect on medial meniscal repair performed at the time of anterior cruciate ligament reconstruction (ACLR). Methods: Retrospective analysis of prospectively collected data was performed to include all patients who had undergone primary ACLR with concomitant posterior horn medial meniscal repair through a posteromedial portal between January 2013 and August 2015. ACLR autograft choice was bone–patellar tendon–bone, hamstring tendons (or quadrupled hamstring tendons), or quadrupled semitendinosus tendon graft with or without ALLR. At the end of the study period, all patients were contacted to determine if they had undergone reoperation. A Kaplan-Meier survival curve was plotted, and a Cox proportional hazards regression model was used to perform multivariate analysis. Results: 383 patients (mean ± SD age, 27.4 ± 9.2 years) were included with a mean follow-up of 37.4 months (range, 24-54.9 months): 194 patients underwent an isolated ACLR, and 189 underwent a combined ACLR + ALLR. At final follow-up, there was no significant difference between groups in postoperative side-to-side laxity (isolated ACLR group, 0.9 ± 0.9 mm [min to max, –1 to 3]; ACLR + ALLR group, 0.8 ± 1.0 mm [min to max, –2 to 3]; P = .2120) or Lysholm score (isolated ACLR group, 93.0 [95% CI, 91.3-94.7]; ACLR + ALLR group, 93.7 [95% CI, 92.3-95.1]; P = .556). Forty-three patients (11.2%) underwent reoperation for failure of the medial meniscal repair or a new tear. The survival rates of meniscal repair at 36 months were 91.2% (95% CI, 85.4%-94.8) in the ACLR + ALLR group and 83.8% (95% CI, 77.1%-88.7%; P = .033) in the ACLR group. The probability of failure of medial meniscal repair was >2 times lower in patients with ACLR + ALLR as compared with patients with isolated ACLR (hazard ratio, 0.443; 95% CI, 0.218-0.866). No other prognosticators of meniscal repair failure were identified. Conclusion: Combined ACLR and ALLR is associated with a significantly lower rate of failure of medial meniscal repairs when compared with those performed at the time of isolated ACLR

How to rapidly abolish knee extension deficit after injury or surgery: a practice-changing video pearl from the Scientific Anterior Cruciate Ligament Network International (SANTI) Study Group

Knee extension deficit is frequently observed after anterior cruciate ligament reconstruction or rupture and other acute knee injuries. Loss of terminal extension often occurs because of hamstring contracture and quadriceps inactivation rather than mechanical intra-articular pathology. Failure to regain full extension in the first few weeks after anterior cruciate ligament reconstruction is a recognized risk factor for adverse long-term outcomes, and therefore, it is important to try to address it. In this technical note, a simple, rapid, and effective technique to help regain full knee extension and abolish quadriceps activation failure is described

Epidemiological evaluation of meniscal ramp lesions in 3214 anterior cruciate ligament–injured knees from the SANTI study group database: a risk factor analysis and study of secondary meniscectomy rates following 769 ramp repairs

Background: Ramp lesions are characterized by disruption of the peripheral meniscocapsular attachments of the posterior horn of the medial meniscus. Ramp repair performed at the time of ACL reconstruction has been shown to improve knee biomechanics. Hypothesis/Purpose: Primary objectives of this study were to evaluate the incidence and risk factors for ramp lesions in a large series of patients undergoing ACL reconstruction, Secondary objectives were to determine the re-operation rate for failure of ramp repair, defined by subsequent re-operations for partial medial meniscectomy Study Design: Case series Methods: All patients underwent trans-notch posteromedial compartment evaluation of the knee during ACL reconstruction. Ramp repair was performed if a lesion was detected. Potentially important risk factors were analyzed for their association with ramp lesions. A secondary analysis of all patients who underwent ramp repair and had a minimum follow-up of two years was undertaken in order to determine the secondary partial meniscectomy rate for failed ramp repair. Results: The overall incidence of ramp lesions in the study population was 23.9% (769 ramp lesions in 3214 patients). Multivariate analysis demonstrated that the presence of ramp lesions was significantly associated with the following risk factors: male gender, patients aged under 30 years, revision ACLR, chronic injuries, pre-operative side-to-side laxity >6 mm and the presence of concomitant lateral meniscus tears. The secondary meniscectomy rate was 10.8% at a mean follow up of 45.6 months (24.2-66.2). Patients who underwent ACLR + ALLR had a greater than 2-fold reduction in the risk of reoperation for failure of ramp repair as compared with patients who underwent isolated ACLR (hazard ratio, 0.457; 95%CI, 0.226-0.864; P = .021). Conclusion: There is a high incidence of ramp lesions in patients undergoing ACLR. The identification of important risk factors for ramp lesions in this study in an individual patient should help raise an appropriate index of suspicion and prompt posteromedial compartment evaluation. The overall secondary partial meniscectomy rate after ramp repair is 10.8%. Anterolateral ligament reconstruction appears to confer a protective effect on the ramp repair performed at the time of ACLR and results in a significant reduction in secondary meniscectomy rates

Combined ACL and anterolateral ligament reconstruction

Background: Clinical results of combined anterior cruciate ligament (ACL) and anterolateral ligament (ALL) reconstruction demonstrate a significant reduction in ACL graft rupture rates and improved return to sport when compared to isolated ACL reconstruction (ACLR). This is supported by laboratory studies which demonstrate that combined ACLR and lateral extra-articular tenodesis (LET) procedures protect the ACL graft by load sharing with it and also by more reliably restoring normal knee kinematics, when compared to isolated ACLR. Description: The ACL graft is formed from a tripled semitendinosus tendon and a single strand of gracilis. The femoral tunnel is drilled to provide an anatomic location intra-articularly and exit the femur just posterior and proximal to the lateral epicondyle. The additional length of gracilis therefore exits the femoral tunnel at the anatomic origin of the ALL and is then routed (under the iliotibial band) through a tibial tunnel, and back to the femoral origin, to reconstruct the ALL. Alternatives: A large number of different types of non- anatomic LET have been reported. The most frequently performed were the Lemaire and MacIntosh procedures but these, and others, were widely abandoned after reports of poor results in the 1980’s. Rationale: ALL reconstruction differs from other lateral extra-articular tenodesis type procedures by virtue of the fact that the procedure is anatomically based and can be percutaneously performed. Nonanatomical procedures (typically with a strand of ITB passed under the LCL) are associated with reports of overconstraint, early arthritis and an increased risk of infection. In contrast, ALLR has been shown to restore normal knee kinematics and avoid overconstraint, when correctly fixed in full extension and neutral rotation. The main concern with any type of LET is based on historical reports of poor outcomes. However, contemporary study demonstrates that combined ACL and ALLR is associated with a re-operation rate that is comparable to the rate seen after isolated ACLR, and a very low rate of complications. This makes a compelling argument for anatomic ALL+ACLR being considered as the procedure of choice when considering an extra-articular procedure. This is further supported by the fact that even though previous studies have demonstrated a trend to reduced ACL graft rupture with non anatomic LETs they have not shown a statistically significant improvement in outcomes. Combined ACL and ALLR is currently the only type of lateral extra- articular procedure that has been demonstrated to significantly reduce ACL graft rupture risk and improve return to sport

The popliteus tendon provides a safe and reliable location for all-inside meniscal repair device placement

Background: Tears of the posterior horn of the lateral meniscus are challenging to repair because, in contrast to medial meniscal repairs, the capsule and its attachment are thin. Purpose: To evaluate the clinical results of an arthroscopic all-inside repair technique for unstable, vertical, lateral meniscus tears, using a suture anchor device placed directly into the popliteus tendon. Study Design: Case Series; Level of evidence, 4. Methods: A retrospective analysis of prospectively collected data from the ***** database was performed. All patients who had undergone combined ACL reconstruction with lateral meniscus all-inside repair, using sutures placed in the popliteus tendon, between January 2011 and February 2015, were included. At final follow-up, all patients were contacted by telephone to identify if they underwent further surgery or had pain, locking or effusion. Symptomatic patients were recalled for clinical/imaging evaluation. Operative notes for those undergoing further surgery were reviewed and rates and type of re-operation, including for failed lateral meniscal repair were recorded. Results: Two hundred patients (mean age, 28.6 ± 10.2 years) with a mean follow-up of 45.5 ± 12.8 months (range, 24.7-75.2) were included. The mean Subjective International Knee Documentation Committee (IKDC) at final follow-up was 85.0 ± 11.3. The post-operative mean side-to-side laxity measured at one year was 0.6 ± 1.0 mm. Twenty-six patients underwent re-operation (13%) at a mean follow-up of 14.8 ± 7.8 months. The ACL graft rupture rate was 5.0%. Other causes for re-operation included medial meniscus tear (2.5%), cyclops lesion (1.5%) and septic arthritis (0.5%). The lateral meniscus repair failure rate was 3.5%. No specific complications relating to placement of suture anchors in the popliteusn tendon were identified. Conclusion: Arthroscopic all-inside repair of unstable, vertical, lateral meniscal tears using a suture anchor placed in the popliteus tendon is a safe, efficient and reproducible technique. It is associated with a very low failure rate without specific complications

Combined anterior cruciate and anterolateral ligament reconstruction in the professional athlete: clinical outcomes from the SANTI Group in a series of seventy patients with a minimum follow up of two years

Purpose: To evaluate clinical outcomes in professional athletes after combined anterior cruciate ligament (ACL) and anterolateral ligament (ALL) reconstruction, with a minimum follow-up of two years. Methods: All professional athletes who underwent primary combined ACL and ALL reconstruction between January 2011 and March 2016 were included. A retrospective analysis of prospectively collected data from the SANTI Study Group database was performed. Patient assessment included physical examination, pre- and postoperative subjective and objective IKDC, Tegner activity scale (TAS) and Lysholm score. Results: 72 professional athletes underwent primary ACL and ALL reconstruction, 70 (97%) were available with a mean follow-up of 3.9 years (range 2-7). The pre-operative side-to-side anteroposterior laxity difference was 7.1 ± 1.4mm and this decreased significantly after surgery to 0.40.9mm (p<0.0001). Pivot-shift grade evolved from 16 grade I (22.8%) and 54 grade II or III (77.2%) preoperatively, to 66 absent pivot shift (94.3%) and 4 grade I (5.7). By one-year post-operatively, sixty athletes (85.7%) returned to professional sport with a mean time interval of 7.9 months (range 5-12). At final follow up the mean subjective IKDC was 90.5 ± 7.6, Lysholm score 94.4 ± 7.5, Tegner 8.8 ± 1.5. 11 Patients (15,7%) underwent a subsequent ipsilateral re-operation including 4 (5.7%) revision ACL reconstructions. Subgroup analysis of early graft failures (within one year or 3 months of first match post-operatively) in professional soccer players demonstrated a significantly lower rate in the current series (0%) when compared against published rates (7%), chi2 8.457 p=0.0036. Conclusions: Combined ACL and ALL reconstruction is associated with excellent outcomes in professional athletes with respect to graft rupture rates, return to sport, knee stability, and re-operation rates after injury. Subgroup analysis in professional soccer players demonstrates that combined ACL and ALL reconstruction is associated with significantly reduced graft rupture rates when compared to isolated ACL reconstruction. Level of evidence: Level IV case series

Integration of Gravitational Torques in Cerebellar Pathways Allows for the Dynamic Inverse Computation of Vertical Pointing Movements of a Robot Arm

Several authors suggested that gravitational forces are centrally represented in the brain for planning, control and sensorimotor predictions of movements. Furthermore, some studies proposed that the cerebellum computes the inverse dynamics (internal inverse model) whereas others suggested that it computes sensorimotor predictions (internal forward model).This study proposes a model of cerebellar pathways deduced from both biological and physical constraints. The model learns the dynamic inverse computation of the effect of gravitational torques from its sensorimotor predictions without calculating an explicit inverse computation. By using supervised learning, this model learns to control an anthropomorphic robot arm actuated by two antagonists McKibben artificial muscles. This was achieved by using internal parallel feedback loops containing neural networks which anticipate the sensorimotor consequences of the neural commands. The artificial neural networks architecture was similar to the large-scale connectivity of the cerebellar cortex. Movements in the sagittal plane were performed during three sessions combining different initial positions, amplitudes and directions of movements to vary the effects of the gravitational torques applied to the robotic arm. The results show that this model acquired an internal representation of the gravitational effects during vertical arm pointing movements.This is consistent with the proposal that the cerebellar cortex contains an internal representation of gravitational torques which is encoded through a learning process. Furthermore, this model suggests that the cerebellum performs the inverse dynamics computation based on sensorimotor predictions. This highlights the importance of sensorimotor predictions of gravitational torques acting on upper limb movements performed in the gravitational field

A General Approach for Predicting the Filtration of Soft and Permeable Colloids: The Milk Example

Membrane filtration operations (ultra-, microfiltration) are now extensively used for concentrating or separating an ever-growing variety of colloidal dispersions. However, the phenomena that determine the efficiency of these operations are not yet fully understood. This is especially the case when dealing with colloids that are soft, deformable, and permeable. In this paper, we propose a methodology for building a model that is able to predict the performance (flux, concentration profiles) of the filtration of such objects in relation with the operating conditions. This is done by focusing on the case of milk filtration, all experiments being performed with dispersions of milk casein micelles, which are sort of ″natural″ colloidal microgels. Using this example, we develop the general idea that a filtration model can always be built for a given colloidal dispersion as long as this dispersion has been characterized in terms of osmotic pressure Π and hydraulic permeability k. For soft and permeable colloids, the major issue is that the permeability k cannot be assessed in a trivial way like in the case for hard-sphere colloids. To get around this difficulty, we follow two distinct approaches to actually measure k: a direct approach, involving osmotic stress experiments, and a reverse-calculation approach, that consists of estimating k through well-controlled filtration experiments. The resulting filtration model is then validated against experimental measurements obtained from combined milk filtration/SAXS experiments. We also give precise examples of how the model can be used, as well as a brief discussion on the possible universality of the approach presented here