Hop Distance Symmetry Moderately Reflects Knee Biomechanics Symmetry During Landing But Not For Controlled Propulsions.

Background: Landing with poor knee sagittal plane biomechanics has been identified as a risk factor for Anterior Cruciate Ligament (ACL) injury. However, it is unclear if the horizontal hop test battery reflects knee function and biomechanics. Hypothesis/Purpose: To investigate the correlation between clinical limb symmetry index (LSI) and landing and propulsion knee biomechanics during the hop test battery using markerless motion capture. Study Design: Cross-sectional biomechanics laboratory study. Methods: Forty-two participants with and without knee surgery (age 28.0 ± 8.0 years) performed the hop test battery which consisted of a single hop for distance, crossover hop, triple hop, and 6-m timed hop in the order listed. Eight high speed cameras were used to collect simultaneous 3D motion data and Theia 3D (Theia Markerless Inc.) was used to generate 3D body model files. Lower limb joint kinematics were calculated in Visual3D. Correlation (Spearman's ρ) was computed between clinical LSI and symmetry in peak and initial contact (IC) knee flexion angle during propulsion and landing phases of each movement. Results: In the single hop, clinical LSI showed positive correlation with kinematic LSI at peak landing (ρ= 0.39, p=0.011), but no correlation at peak propulsion (ρ= -0.03, p=0.851). In the crossover hop, non-significant correlations were found in both propulsion and landing. In the triple hop, positive correlation was found at peak propulsion (ρ= 0.38, p=0.027), peak landing (ρ= 0.48 - 0.66, p<0.001), and last landing IC (ρ= 0.45, p=0.009). In the timed hop, peak propulsion showed positive correlation (ρ= 0.51, p=0.003). Conclusions: Single hop and triple hop distance symmetry reflected landing biomechanical symmetry better than propulsion symmetry. Poor scores on the hop test battery reflect asymmetrical knee landing biomechanics, emphasizing the importance of continuing to use the hop test battery as part of clinical decision making. Level of Evidence: 3b.

Regional healing trajectory of the patellar tendon after bone-patellar tendon-bone autograft harvest for anterior cruciate ligament reconstruction.

Graft site morbidities after bone-patellar tendon-bone (BPTB) autograft harvest for anterior cruciate ligament reconstruction (ACLR) negatively impacts rehabilitation. The purpose of this study was to establish tendon structural properties 1-month after BPTB autograft harvest compared to the uninvolved patellar tendon, and subsequently to quantify the healing trajectory of the patellar tendon over the course of rehabilitation. Patellar tendon morphology (ultrasound) and mechanical properties (continuous shear wave elastography) from 3 regions of the tendon (medial, lateral, central) were measured in 34 participants at 1 month, 3-4 months, and 6-9 months after ACLR. Mixed models were used to compare tendon structure between limbs at 1 month, and quantify healing over 3 timepoints. The involved patellar tendon had increased cross-sectional area and thickness in all regions 1-month after ACLR. Thickness reduced uniformly over time. Possible tendon elongation was observed and remained stable over time. Tendon viscosity was uniform across the three regions in the involved limb while the medial region had higher viscosity in the uninvolved limb, and shear modulus was elevated in all three regions at 1 month. Viscosity and shear modulus in only the central region reduced over time. Statement of Clinical Significance: The entire patellar tendon, and not just the central third, is altered after graft harvest. Tendon structure starts to normalize over time, but alterations remain especially in the central third at the time athletes are returning to sport. Early rehabilitation consisting of tendon loading protocols may be necessary to optimize biologic healing at the graft site tendon.

The Delaware-Oslo ACL Cohort treatment algorithm yields superior outcomes to usual care 9-12 years after anterior cruciate ligament reconstruction.

PURPOSE: Patient-reported outcomes were compared between participants who followed the treatment algorithm of the Delaware-Oslo ACL Cohort, consisting of progressive preoperative and postoperative rehabilitation, patient education, clinical testing and shared decision-making about treatment choice, and those who followed usual care 9-12 years after anterior cruciate ligament reconstruction (ACLR). METHODS: Participants with primary ACLR were included from the Norwegian arm of the Delaware-Oslo ACL Cohort and the Norwegian Knee Ligament Registry (usual care). The Knee Injury and Osteoarthritis Outcome Score (KOOS) subscale scores and the International Knee Documentation Committee-Subjective Knee Form (IKDC-SKF) scores were compared. KOOS scores for the usual care group were converted to IKDC-SKF scores with recently published validated crosswalk. The percentages of participants with scores above predefined thresholds for patient acceptable symptom state (PASS) were also calculated. RESULTS: Eighty of 100 (80%) participants from the Delaware-Oslo ACL Cohort and 1588 of 3248 (49%) from the usual care group participated in the follow-up. Participants from the Delaware-Oslo ACL Cohort had higher KOOS subscale (p < 0.001) and IKDC-SKF scores (p < 0.001), and a higher percentage reached PASS (84%-96% vs. 62%-76%, p ≤ 0.002) for KOOS Pain, symptoms, activities of daily living and sports compared to the usual care group. No significant differences were found for KOOS quality of life scores (not significant [n.s.]) or PASS percentages (80% vs. 74%, n.s.). CONCLUSION: Participants with ACLR who followed the Delaware-Oslo ACL Cohort treatment algorithm had reduced knee symptoms, superior function and higher percentages of satisfactory outcomes than participants who followed usual care. LEVEL OF EVIDENCE: Level II.

Unbalanced Medial-to-Lateral Knee Muscle Co-Contractions are Associated with Medial Tibiofemoral Underloading during Gait Three Months after Anterior Cruciate Ligament Reconstruction.

Altered medial/lateral knee muscle co-contraction (measure by co-contraction indices, CCI) occurs during gait early after anterior cruciate ligament reconstruction (ACLR). Changes in peak medial compartment forces (pMCF) are also observed early after ACLR and are linked to the development of knee osteoarthritis. We do not know if imbalanced co-contraction is associated with these alterations in knee load. The purpose of this study was to evaluate the association between pMCF and the CCIs of medial/lateral knee muscle pairs during walking three months after ACLR. Bilateral knee gait mechanics and electromyography (EMG) data were collected from 44 participants 3 months following surgery. CCIs of six muscle pairs and medial-to-lateral (M:L) CCIs ratios were calculated during the weight acceptance interval. Bilateral pMCFs were calculated using a subject-based neuromusculoskeletal model. Based on interlimb pMCF symmetry, participants were divided into three groups: symmetric loaders, underloaders, and overloaders. A 2 × 3 (limb × group) ANOVA was used to compare CCIs between limbs in all groups. A partial Spearman's test was performed to examine the association between CCIs ratios and pMCF. The CCIs of the vastus lateralis-lateral gastrocnemius muscle pair was higher in the involved limb of underloaders (vs. the uninvolved limb and vs. the involved limb of symmetric loaders). The ratio of M:L CCIs was significantly lower (more lateral CCIs) in the involved limb, which was associated with lower pMCF. These results suggest that individuals early after ACLR who walk with higher CCIs of lateral knee musculature (vs. medial), have medial tibiofemoral underloading.

Time to treat the tendon rupture induced by surgery: early hypertrophy of the patellar tendon graft site predicts strong quadriceps after ACLR with bone-patellar tendon-bone autograft.

PURPOSE: Quadriceps dysfunction is ubiquitous after anterior cruciate ligament reconstruction, especially when using bone-patellar tendon-bone (BPTB) autografts. The role of patellar tendon hypertrophy after graft harvest on knee extensor strength is unknown. The purpose of this study was to determine the predictive ability of patellar tendon (PT) and quadriceps muscle (Quad) cross-sectional area (CSA) on knee extensor strength 1-2 months after ACLR using BPTB autografts. METHODS: This is a cross-sectional analysis of a cohort 1-2 months after ACLR using BPTB autograft. Peak knee extensor torque, and PT and Quad CSA measured using ultrasound imaging, were collected in 13 males and 14 females. Simple linear regressions compared quadriceps strength index (QI) against limb symmetry index (LSI) in PT and Quad CSA. Multiple linear regressions with sequential model comparisons predicting peak knee extensor torque were performed for each limb. The base model included demographics. Quad CSA was added in the first model, then PT CSA was added in the second model. RESULTS: Both PT (p < 0.001, R2 = 0.693) and Quadriceps CSA (p = 0.013, R2 = 0.223) LSI had a positive linear relationship with QI. In the involved limb, addition of PT CSA significantly improved the model (R2 = 0.781, ΔR2 = 0.211, p for ΔR2 < 0.001). In the uninvolved limb, the addition of Quad CSA improved the model, but the addition of PT CSA did not. CONCLUSION: PT LSI was more predictive of QI than Quad CSA LSI. Involved limb PT CSA mattered more in predicting peak knee extensor torque than did Quad CSA, but in the uninvolved limb, Quad CSA was the most important predictor of peak knee extensor torque. Graft site patellar tendon hypertrophy is key for strong quadriceps early after ACLR. Early targeted loading via exercise to promote healing of the graft site patellar tendon may bring patients a step closer to winning their battle against quadriceps dysfunction. LEVEL OF EVIDENCE: Level I.

Bone-Patellar Tendon-Bone Autograft Harvest Prolongs Extensor Latency during Gait 2 yr after ACLR.

PURPOSE: Bone-patellar tendon-bone (BPTB) graft harvest for anterior cruciate ligament reconstruction alters patellar tendon properties, which inflict poor quadriceps neuromuscular function. BPTB autografts are associated with higher rates of posttraumatic osteoarthritis, which in turn is associated with pathological gait. The purpose of this study was to investigate the latency between the time of peak quadriceps activity and the peak knee flexion moment during gait, between those with BPTB grafts ( n = 23) and other graft types (hamstring autograft or allografts, n = 54), 5 ± 2 months and 2 yr (25 ± 3 months) after anterior cruciate ligament reconstruction. We hypothesized that longer latencies would be observed in the BPTB graft group in the involved limb. We expected latencies to shorten over time. METHODS: Knee moments and quadriceps EMG were collected during gait, and vastus medialis, vastus lateralis, rectus femoris (RF), and quadriceps latencies were calculated. Linear mixed-effects models were used to compare latencies between graft types and over the two time points. RESULTS: The main effects of graft type were observed for vastus medialis ( P = 0.005) and quadriceps ( P = 0.033) latencies with the BPTB graft group demonstrating longer latencies. No main effects of graft type were observed for vastus lateralis ( P = 0.051) and RF ( P = 0.080) latencies. Main effects of time were observed for RF latency ( P = 0.022). CONCLUSIONS: Our hypothesis that the BPTB graft group would demonstrate longer extensor latency was supported. Contrary to our second hypothesis, however, latency only improved in RF and regardless of graft type, indicating that neuromuscular deficits associated with BPTB grafts may persist 2 yr after surgery. Persistent deficits may be mediated by changes in the patellar tendon's mechanical properties. Graft-specific rehabilitation may be warranted to address the long-term neuromechanical deficits that are present after BPTB graft harvest.

Creating Crosswalks for Knee Outcomes After ACL Reconstruction Between the KOOS and the IKDC-SKF.

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 Documentation Committee-Subjective Knee Form (IKDC-SKF) scores and vice versa to allow these comparisons. METHODS: Data from 3 ACL registries were pooled (n = 14,412) and were separated into a training data set (70% of the sample) or a validation data set (30% of the sample). The KOOS and the IKDC-SKF scores were available prior to the operation and at 1, 2, and 5 or 6 years postoperatively. We used equipercentile equating methods to create crosswalks in the training data set and examined accuracy in the validation data set as well as bootstrapping analyses to assess the impact of sample size on accuracy. RESULTS: Preliminary analyses suggested that crosswalks could be attempted: large correlations between scores on the 2 measures (r = 0.84 to 0.94), unidimensionality of scores, and subpopulation invariance were deemed sufficient. When comparing actual scores with crosswalked scores in the validation data set, negligible bias was observed at the group level; however, individual score deviations were variable. The crosswalks are successful for the group level only. CONCLUSIONS: Our crosswalks successfully convert between the KOOS and the IKDC-SKF scores to allow for a group-level comparison of registry and other cohort data. CLINICAL RELEVANCE: These crosswalks allow comparisons among different national ligament registries as well as other research cohorts and studies; they also allow data from different patient-reported outcome measures to be pooled for meta-analysis. These crosswalks have great potential to improve our understanding of recovery after ACL reconstruction and aid in our ongoing efforts to improve outcomes and patient satisfaction, as well as to allow the continued analysis of historical data.

Knee joint biomechanics during gait improve from 3 to 6 months after anterior cruciate ligament reconstruction.

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 much known about how they differ over the entire stance phase of gait. The purpose of this study was to examine knee gait biomechanical variables over their entire movement pattern through stance at both 3 and 6 months after ACLR and to study the progression of interlimb asymmetry between the two postoperative time points. Thirty-five individuals underwent motion analysis during overground walking 3 (3.2 ± 0.5) and 6 (6.4 ± 0.7) months after ACLR. Knee biomechanical variables were compared between limbs and across time points through 100% of stance using statistical parametric mapping; this included a 2 × 2 (Limb × Time) repeated measures analysis of variance and two-tailed t-tests. Smaller knee joint angles, moments, extensor forces, and medial compartment forces were present in the involved versus uninvolved limb. Interlimb asymmetries were present at both time points but were less prevalent at 6 months. The uninvolved limb's biomechanical variables stayed relatively consistent over time, while the involved limb's trended toward that of the uninvolved limb. Statement of Clinical Significance: Interventions to correct asymmetrical gait patterns after ACLR may need to occur early after surgery and may need to focus on multiple parts of stance phase.

Knee biomechanics and contralateral knee osteoarthritis progression after total knee arthroplasty.

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 progression in the contralateral (non-surgical) knee after unilateral (primary/initial) TKA. In addition, this study quantified for patients who had contralateral OA progression. METHODS: Biomechanical outcomes were collected 6-24 months after unilateral primary TKA and were used to predict changes in contralateral OA severity at follow-up. Participants were divided into "Progressor" and "Non-Progressor" groups based on changes in Kellgren-Lawrence (KL) OA grade and Joint Space Width (JSW) between baseline and follow-up testing sessions. Biomechanical factors during walking were peak knee adduction moment, knee flexion/extension excursions, knee angle at initial foot contact, and peak knee flexion/extension. Multiple independent t-tests were used to examine the magnitude of differences in biomechanical variables between the groups. Logistic regression was used to examine the association between the biomechanical predictors and change in KL scores and JSW. RESULTS: The mean time between surgery and follow-up x-rays was 8.8 (2.4) years. Of 40 participants, 62.5-78% had contralateral radiographic knee OA progression by follow-up. There were no significant differences in the biomechanical variables between groups. For the regression analysis, none of the biomechanical variables were found to be predictors for contralateral OA progression. SIGNIFICANCE: Although abnormal biomechanics are known risk factors for primary knee OA, it is possible that the mechanisms that result in OA progression of the contralateral limb are different than primary knee OA progression. Future work should evaluate other objective measures of OA progression and determine if cumulative measures of joint loading are related to OA worsening.

Knee cartilage T2 relaxation times 3 months after ACL reconstruction are associated with knee gait variables linked to knee osteoarthritis.

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, 45 individuals (age, 23 ± 7 years) underwent motion analysis during walking and qMRI 3 months after ACLR. For each limb, peak knee adduction moment (pKAM) and peak knee flexion moment (pKFM) were determined using inverse dynamics and peak medial compartment force was calculated using a neuromusculoskeletal model. T2 relaxation times in the medial compartment and linear regressions were used to determine the associations between gait variables and deep and superficial cartilage T2 relaxation times in six regions. pKAM was positively associated with deep layer T2 relaxation times within the femoral central and posterior regions when examined in the involved limb and from an interlimb difference perspective (involved limb - uninvolved limb). After adjusting for age, the association between interlimb difference of pKAM and interlimb difference of deep layer T2 relaxation times in the tibial central region became significant (p = .043). Interlimb difference of pKFM was negatively associated with interlimb difference of deep layer T2 relaxation times within the femoral central and posterior regions. These associations suggest that degenerative pathways leading to osteoarthritis may be detectable as early as 3 months after reconstruction. Preventative therapeutic techniques may need to be employed early in the rehabilitation process to prevent cartilage degradation.

Clinical, Functional, and Physical Activity Outcomes 5 Years Following the Treatment Algorithm of the Delaware-Oslo ACL Cohort Study.

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 followed our decision-making and treatment algorithm and chose (1) early ACLR with preoperative and postoperative rehabilitation, (2) delayed ACLR with preoperative and postoperative rehabilitation, or (3) progressive rehabilitation alone. Early ACLR was defined as that performed ≤6 months after the preoperative rehabilitation program, and late ACLR was defined as that performed >6 months after the preoperative rehabilitation program. METHODS: We included 276 patients from a prospective cohort study. The patients had been active in jumping, pivoting, and cutting sports before the injury and sustained a unilateral ACL injury without substantial concomitant knee injuries. The patients chose their treatment through a shared decision-making process. At 5 years, we assessed the International Knee Documentation Committee Subjective Knee Form (IKDC-SKF), Knee injury and Osteoarthritis Outcome Score (KOOS), Marx Activity Rating Scale, sports participation, quadriceps muscle strength, single-legged hop performance, and new ipsilateral and contralateral knee injuries. RESULTS: The 5-year follow-up rate was 80%. At 5 years, 64% of the patients had undergone early ACLR, 11% had undergone delayed ACLR, and 25% had had progressive rehabilitation alone. Understandably, the choices that participants made differed by age, concomitant injuries, symptoms, and predominantly level-I versus level-II preinjury activity level. There were no significant differences in any clinical, functional, or physical activity outcomes among the treatment groups. Across treatment groups, 95% to 100% of patients were still active in some kind of sports and 65% to 88% had IKDC-SKF and KOOS scores above the threshold for a patient acceptable symptom state. CONCLUSIONS: Patients with ACL injury who were active in jumping, pivoting, and cutting sports prior to injury; who had no substantial concomitant knee injuries; and who followed our decision-making and treatment algorithm had good 5-year knee function and high sport participation rates. Three of 4 patients had undergone ACLR within 5 years. There were no significant differences in any outcomes among patients treated with early ACLR, delayed ACLR, or progressive rehabilitation alone. LEVEL OF EVIDENCE: Therapeutic Level II. See Instructions for Authors for a complete description of levels of evidence.

Rehabilitation duration and time of starting sport-related activities associated with return to the previous level of sports after anterior cruciate ligament reconstruction.

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 levels, injury profile, rehabilitation duration, and time to start sport-related activities (running, cutting-pivoting) after ACLR. Athletes answered whether they returned to the same previous level of frequency, duration, and intensity of sports. MAIN OUTCOME MEASURES: Athletes' characteristics, injury and surgical factors, duration of post-operative rehabilitation program, and time to start sport-related activities after ACLR were evaluated by univariate logistic regression to determine predictors for return to previous level of sports. RESULTS: Nine athletes (10%) returned to their self-described previous level of sports. Predictors for returning to previous level of sports were rehabilitation duration >4 months (OR:6.78; p = .011), time to start running ≤4 months (OR:8.62; p = .047) and cutting-pivoting <6 months after surgery (OR:5.02; p = .030). CONCLUSION: Longer post-operative rehabilitation duration and time to start sport-related activities after ACLR predicted return to previous level of sports. Spending adequate time in post-operative rehabilitation program and time-based resumption of sports-related activities after ACLR might be key factors for returning to previous sports level.

Athletes after anterior cruciate ligament reconstruction demonstrate asymmetric intracortical facilitation early after surgery.

Quadriceps dysfunction persists after anterior cruciate ligament reconstruction (ACLR), yet the etiology remains elusive. Inhibitory and facilitatory intracortical networks (ie, 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 to examine (a) changes in intracortical excitability in athletes after ACLR compared to uninjured athletes during the course of postoperative rehabilitation, (b) the association between intracortical excitability and quadriceps strength in athletes after ACLR. Eighteen level I/II athletes after ACLR between the ages of 18 to 30 years and eighteen healthy sex, age, and activity matched athletes were tested at three-time points: (a) 2 weeks after surgery, (b) achievement of a "quiet knee" defined as full range of motion and minimal effusion, (c) return to running time point defined as achievement of a quadriceps index ≥80% and at least 12 weeks post-ACLR. Short-interval intracortical inhibition (SICI) and intracortical facilitation (ICF), measured via transcranial magnetic stimulation and isometric quadriceps strength were examined bilaterally at each time point. There was a significant group × limb interaction (P = .017) for ICF. The ACLR group demonstrated asymmetric ICF (greater in the nonsurgical limb) compared to controls and a significant relationship between SICI and quadriceps strength of the surgical limb at the quiet knee time point (P = .018). ACLR individuals demonstrate differential effects on ICF between limbs. Also, SICI is associated with isometric quadriceps strength after ACLR, suggesting increased inhibition of the motor cortex may contribute to impaired quadriceps strength following ACLR.

Meniscus or Cartilage Injury at the Time of Anterior Cruciate Ligament Tear Is Associated With Worse Prognosis for Patient-Reported Outcome 2 to 10 Years After Anterior Cruciate Ligament Injury: A Systematic Review.

OBJECTIVES: (1) To assess prognostic factors for patient-reported outcome measures (PROMs) and physical activity 2 to 10 years after anterior cruciate ligament reconstruction (ACLR) or anterior cruciate ligament (ACL) injury, and (2) to assess differences in prognostic factors between patients treated with ACLR and with rehabilitation alone. DESIGN: Prognosis systematic review. LITERATURE SEARCH: Systematic searches were performed in PubMed, Web of Science, and SPORTDiscus. STUDY SELECTION CRITERIA: We selected prospective cohort studies and randomized clinical trials that included adults or adolescents undergoing either ACLR or rehabilitation alone after ACL rupture. Studies had to assess the statistical association between potential prognostic factors (factors related to patient characteristics, injury, or knee symptoms/function measured at baseline or within 1 year) and outcomes (PROMs and physical activity). DATA SYNTHESIS: Our search yielded 997 references. Twenty studies met the inclusion criteria. Seven studies with low or moderate risk of bias remained for data synthesis. RESULTS: Moderate-certainty evidence indicated that concomitant meniscus and cartilage injuries were prognostic factors for worse PROMs 2 to 10 years after ACLR. Very low-certainty evidence suggested that body mass index, smoking, and baseline PROMs were prognostic factors for worse outcome. Very low-certainty evidence suggested that female sex and a worse baseline Marx Activity Rating Scale score were prognostic factors for a worse Marx Activity Rating Scale score 2 to 10 years after ACLR. There was a lack of studies on prognostic factors after rehabilitation alone. CONCLUSION: Concomitant meniscus and cartilage injuries were prognostic factors for worse long-term PROMs after ACLR. The certainty was very low for other prognostic factors. J Orthop Sports Phys Ther 2020;50(9):490-502. Epub 1 Aug 2020. doi:10.2519/jospt.2020.9451.

Examination of Corticospinal and Spinal Reflexive Excitability During the Course of Postoperative Rehabilitation After Anterior Cruciate Ligament Reconstruction.

OBJECTIVE: To investigate corticospinal and spinal reflexive excitability and quadriceps strength in healthy athletes and athletes after anterior cruciate ligament reconstruction (ACLR) over the course of rehabilitation. DESIGN: Prospective cohort study. METHODS: Eighteen athletes with ACLR and 18 healthy athletes, matched by sex, age, and activity, were tested at (1) 2 weeks after surgery, (2) the "quiet knee" time point, defined as full range of motion and minimal effusion, and (3) return to running, defined as achieving a quadriceps index of 80% or greater. We measured (1) corticospinal excitability, using resting motor threshold (RMT) and motor-evoked potential amplitude at a stimulator intensity of 120% of RMT (MEP120) to the vastus medialis, (2) spinal reflexive excitability, calculating the ratio of the maximal Hoffmann reflex to the maximal M-wave to the vastus medialis, and (3) isometric quadriceps strength. RESULTS: The ACLR group had higher RMTs in the nonsurgical limb and higher MEP120 in the surgical limb at all time points. The healthy-athlete group did not have interlimb differences. The RMT was positively associated with quadriceps strength 2 weeks after surgery; MEP120 was associated with quadriceps strength at all time points. CONCLUSION: Compared to healthy athletes, athletes after ACLR had altered corticospinal excitability that did not change from 2 weeks after surgery to the time of return to running. J Orthop Sports Phys Ther 2020;50(9):516-522. Epub 1 Aug 2020. doi:10.2519/jospt.2020.9329.

Treatment After Anterior Cruciate Ligament Injury: Panther Symposium ACL Treatment Consensus Group.

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 the best available evidence on operative versus nonoperative treatment for ACL injury. The purpose of this study was to report the consensus statements on operative versus nonoperative treatment of ACL injuries developed at the ACL Consensus Meeting Panther Symposium 2019. There were 66 international experts on the management of ACL injuries, representing 18 countries, who were convened and participated in a process based on the Delphi method of achieving consensus. Proposed consensus statements were drafted by the scientific organizing committee and session chairs for the 3 working groups. Panel participants reviewed preliminary statements before the meeting and provided initial agreement and comments on the statement via online survey. During the meeting, discussion and debate occurred for each statement, after which a final vote was then held. Ultimately, 80% agreement was defined a priori as consensus. A total of 11 of 13 statements on operative versus nonoperative treatment of ACL injury reached consensus during the symposium. Overall, 9 statements achieved unanimous support, 2 reached strong consensus, 1 did not achieve consensus, and 1 was removed because of redundancy in the information provided. In highly active patients engaged in jumping, cutting, and pivoting sports, early anatomic ACL reconstruction is recommended because of the high risk of secondary meniscal and cartilage injuries with delayed surgery, although a period of progressive rehabilitation to resolve impairments and improve neuromuscular function is recommended. For patients who seek to return to straight-plane activities, nonoperative treatment with structured, progressive rehabilitation is an acceptable treatment option. However, with persistent functional instability, or when episodes of giving way occur, anatomic ACL reconstruction is indicated. The consensus statements derived from international leaders in the field will assist clinicians in deciding between operative and nonoperative treatment with patients after an ACL injury.

Comparing the Responsiveness of the Global Rating Scale With Legacy Knee Outcome Scores: A Delaware-Oslo Cohort Study.

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 compare data across providers and studies. HYPOTHESIS/PURPOSE: The purpose was to determine the responsiveness of 4 PROMs via effect size and the presence of a ceiling effect in the 5 years after anterior cruciate ligament reconstruction (ACLR). We hypothesized that the single-item Global Rating Scale (GRS) would have an effect size and ceiling effect similar to the commonly used legacy PROMs. STUDY DESIGN: Cohort study (diagnosis); Level of evidence, 2. METHODS: Of the 300 participants, 218 had ACLR, completed postoperative progressive criterion-based rehabilitation early after surgery, and were followed for 5 years. We collected data based on the GRS, the Knee Outcome Survey-Activities of Daily Living Scale (KOS-ADLS), the International Knee Documentation Committee-Subjective Knee Form (IKDC-SKF), and the KOOS (Knee injury and Osteoarthritis Outcome Score) before and after training and at 6, 12, 24, and 60 months after ACLR. RESULTS: The IKDC-SKF had the largest effect sizes and lowest ceiling effects. The GRS had a similar size and change in both effect size and ceiling effect when compared with the longer PROMs. The GRS and IKDC-SKF had a correlation of 0.72, and the GRS had a minimal detectable change of 2.9 or 4.8, depending on methodology. CONCLUSION: The GRS responded similarly to the IKDC-SKF, KOS-ADLS, and KOOS and was responsive to patient change. The ease of use and patient-specific nature of the question means that it may be appropriate to use the GRS in clinical care as a consistent measure throughout the course of rehabilitation.

ACL injury and reconstruction affect control of ground reaction forces produced during a novel task that simulates cutting movements.

After anterior cruciate ligament (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 first 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. Nonlinear analysis metrics, such as the largest Lyapunov exponent (LyE) can provide new biomechanical insight in this population by identifying how movement patterns evolve over time. The purpose of this study was to determine how ACL injury, ACL reconstruction (ACLR), and participation in high-performance athletics affect control strategies, evaluated through nonlinear analysis, produced during a novel task that simulates forces generated during cutting movements. Uninjured recreational athletes, those with ACL injury who have not undergone reconstruction (ACLD [ACL deficient]), those who have undergone ACL reconstruction, and high-performance athletes completed a task that simulates cutting forces. The LyE calculated from forces generated during this novel task was greater (ie, force control was diminished) in the involved limb of ACLD and ACLR groups when compared with healthy uninjured controls and high-performance athletes. These data suggest that those who have experienced an ACL injury and subsequent reconstructive surgery exhibit poor force control when compared with both uninjured controls and high-performance athletes. Clinical significance: significantly larger LyE values after ACL injury and reconstruction when compared with healthy athletes suggest a continuing deficit in force control not addressed by current rehabilitation protocols and evaluation metrics that could contribute to secondary ACL rupture.

Athletes With Bone-Patellar Tendon-Bone Autograft for Anterior Cruciate Ligament Reconstruction Were Slower to Meet Rehabilitation Milestones and Return-to-Sport Criteria Than Athletes With Hamstring Tendon Autograft or Soft Tissue Allograft : Secondary Analysis From the ACL-SPORTS Trial.

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. The objective was to assess time to meet clinical milestones by graft type in athletes who completed a return-to-sport (RTS) program after ACLR. DESIGN: Retrospective cohort study. METHODS: Seventy-nine athletes enrolled after ACLR (allograft, n = 18; BPTB, n = 24; HT, n = 37). Time from surgery to meet (1) enrollment criteria (12 or more weeks post surgery, 80% or greater isometric quadriceps strength index, minimal effusion, and full knee range of motion), and (2) RTS criteria (90% or greater quadriceps strength index, hop testing limb symmetry, and patient-reported outcomes) was calculated. Quadriceps strength, hop performance, and patient-reported outcomes were measured before and after training, and at 1 year post surgery. Descriptive statistics, chi-square tests, and 1-way analyses of variance (α = .05) were used to analyze differences among graft types. RESULTS: On average, the BPTB group (28.5 ± 7.6 weeks) took longer to meet enrollment milestones than the HT (22.5 ± 7.6 weeks, P = .007) and allograft (18.9 ± 5.8 weeks, P<.001) groups. The BPTB group (44.7 ± 15.8 weeks) took longer from surgery to meet RTS criteria than the HT (32.5 ± 9.9 weeks, P = .001) and allograft (29.3 ± 9.0 weeks, P<.001) groups. After training, the quadriceps strength index was lower in the BPTB group (86.1% ± 11.4%) than it was in the HT (96.1% ± 12.9%, P = .004) and allograft (96.9% ± 5.9%, P = .009) groups. CONCLUSION: Athletes with a BPTB autograft may take longer than athletes with an HT autograft or a soft tissue allograft to complete postoperative rehabilitation, recover quadriceps strength, and meet RTS criteria. J Orthop Sports Phys Ther 2020;50(5):259-266. Epub 27 Nov 2019. doi:10.2519/jospt.2020.9111.

Partial medial meniscectomy leads to altered walking mechanics two years after anterior cruciate ligament reconstruction: Meniscal repair does not.

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 influence walking biomechanics two years after ACLR is unknown. RESEARCH QUESTION: Does medial meniscus treatment at the time of ACLR influence walking biomechanics two years after surgery? METHODS: This is a secondary analysis of prospectively collected data from a clinical trial (NCT01773317). Fifty-six athletes (age 24 ±â€¯8 years) with operative reports, two-year biomechanical analyses, and no second injury prior to two-year testing participated after primary ACLR. Participants were classified by concomitant medial meniscal status: no medial meniscus involvement (n = 36), partial medial meniscectomy (n = 9), and medial meniscus repair (n = 11). Participants underwent biomechanical analyses during over-ground walking including surface electromyography; a validated musculoskeletal model estimated medial compartment tibiofemoral contact forces. Gait variables were analyzed using 3 × 2 ANOVAs with group (medial meniscus treatment) and limb (involved versus uninvolved) comparisons. RESULTS: There was a main effect of group (p = .039) for peak knee flexion angle (PKFA). Participants after partial medial meniscectomy walked with clinically meaningfully smaller PKFAs in both the involved and uninvolved limbs compared to the no medial meniscus involvement group (group mean difference [95%CI]; involved: -4.9°[-8.7°, -1.0°], p = .015; uninvolved: -3.9°[-7.6°, -0.3°], p = .035) and medial meniscus repair group (involved: -5.2°[-9.9°, -0.6°], p = .029; uninvolved: -4.7°[-9.0°, -0.3°], p = .038). The partial medial meniscectomy group walked with higher involved versus uninvolved limb medial tibiofemoral contact forces (0.45 body weights, 95% CI: -0.01, 0.91 BW, p = 0.053) and truncated sagittal plane knee excursions, which were not present in the other two groups. SIGNIFICANCE: Aberrant gait biomechanics may concentrate high forces in the antero-medial tibiofemoral cartilage among patients two years after ACLR plus partial medial meniscectomy, perhaps explaining the higher osteoarthritis rates and offering an opportunity for targeted interventions. LEVEL OF EVIDENCE: Level III.