Exercise with Blood Flow Restriction to Improve Quadriceps Function Long After ACL Reconstruction.

Objectives: Blood flow restriction training (BFRT) involves obstruction of venous outflow of working muscles during exercise and may lead to more substantial recovery of quadriceps strength after anterior cruciate ligament (ACL) reconstruction. The purpose of this study is to examine the effects of BFRT in ACL reconstruction patients before and after exposure to BFRT. Methods: This study was a randomized controlled trial in which 36 patients who had torn their ACL and were scheduled to undergo ACL reconstructive surgery (ACLR) with an autograft were randomized to receive exercise with BFRT (N=18) or exercise without BFRT (N=18). Participants in both groups performed the same exercise, but either did or did not have blood flow restricted. The exercise component of the intervention consisted of all subjects performing a single-leg isokinetic leg press, at an intensity of 70% of the subjects’ one-repetition maximum, for four sets of ten repetitions two times per week for 8 weeks beginning at 8 weeks post-operatively. Patients randomized to the BFRT group performed the leg-press exercise with a blood flow restriction cuff applied to the thigh and set to a limb occlusion pressure of 80 percent. All participants were concurrently undergoing standard ACL rehabilitation at the same physical therapy clinic. Bilateral isometric (recorded at a knee angle of 90°) and isokinetic (60°/second) quadriceps strength were recorded using a Biodex dynamometer (System 4, Shirley, NY) prior to ACLR and after the conclusion of the 8-week intervention. Peak isometric and isokinetic quadriceps strength were utilized to generate isometric and isokinetic quadriceps symmetry indices ((ACLR limb strength/Healthy limb strength) x100). Change from baseline symmetry scores were then generated using the following equation: (post-intervention symmetry - pre-intervention symmetry)/pre-intervention symmetry in order to account for possible differences in strength between groups prior to intervention delivery. Change from baseline isometric and isokinetic quadriceps symmetry scores were then compared between groups (exercise with BFRT, exercise without BFRT) using one-way analysis of variance tests with an a priori α set to P≤ 0.05. Effect sizes (Cohen’s d) and 95% confidence intervals were also computed. Results: No significant differences were found for change from baseline isokinetic quadriceps symmetry index (P=0.39, BFRT mean=-0.05, Control mean=-0.19) or change from baseline isometric quadriceps symmetry index (P=0.62, BFRT mean=-0.04, control mean=-0.10). The effect sizes for isokinetic quadriceps symmetry index (d=0.28, 95% CI= -0.37, 0.93) and isometric quadriceps symmetry (d=0.16, 95% CI= -0.49, 0.80) were small with confidence intervals that crossed zero. Conclusion: An 8-week blood flow resistance training + exercise intervention did not increase quadriceps muscle strength in patients who had undergone ACL reconstruction. Based on our findings, application of blood flow restriction training in ACL reconstruction patients to improve quadriceps strength may not be warranted. Future studies may benefit from a longer follow-up and larger sample size.

Clinical Scenario: Quadriceps atrophy and weakness are common after anterior cruciate ligament reconstruction (ACLR). Blood flow restriction (BFR) therapy, alone or in combination with exercise, has shown some promise in promoting muscular hypertrophy. This review was conducted to ascertain the extent to which current evidence supports the use of BFR for reducing quadriceps atrophy following ACLR in comparison with standard care. Clinical Question: Is BFR more effective than standard care for reducing quadriceps atrophy after ACLR? Summary of Key Findings: The literature was searched for studies that directly compared BFR treatment to standard care in patients with ACLR. Three level I randomized control trial studies retrieved from the literature search met the inclusion criteria. Clinical Bottom Line: Reviewed data suggest that a short duration (13d) of moderate-pressure BFR combined with low-resistance muscular training does not appear to measurably affect quadriceps cross-sectional area. However, a relatively long duration (15wk) of moderate-pressure BFR combined with low-resistance muscular training may increase quadriceps cross-sectional area to a greater extent than low-resistance muscular training alone. The results of the third randomized control trial suggest that employing BFR while immobilized in the early postoperative period may reduce quadriceps atrophy following ACLR. Additional data are needed to establish if the benefits of BFR on quadriceps atrophy after ACLR outweigh the inherent risks and costs. Strength of Recommendation: All evidence for this review was level 1 (randomized control trial) based on the Centre for Evidence-Based Medicine criteria. However, the findings were inconsistent across the 3 studies regarding the effects of BFR on quadriceps atrophy resulting in a grade "B" strength of recommendation.

Background: The optimal timing of anterior cruciate ligament (ACL) reconstruction (ACLR) remains a controversial topic. Previous reviews have demonstrated that there are no differences between early and delayed ACLR; however, these studies have been limited by heterogeneous definitions of acute ACL injury. Purpose: To evaluate postoperative patient functional outcomes and risk for arthrofibrosis after acute arthroscopic ACLR performed ≤10 days after injury. Study Design: Systematic review; Level of evidence, 4. Methods: A systematic review was performed according to PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines using multiple medical databases. Inclusion criteria were studies that evaluated postoperative range of motion outcomes for patients undergoing ACLR ≤10 days after initial ACL injury. For included comparative studies comparing patient groups undergoing ACLR ≤10 days and patients undergoing “delayed” ACLR after ≥3 weeks of initial injury, quantitative analysis was performed to assess for differences in postoperative arthrofibrosis, reoperation rates, and patient-reported outcomes between groups. DerSimonian-Laird binary random-effects models were constructed to quantitatively describe the association between the ACLR time period and patient outcomes by generating effect estimates in the form of odds ratios with 95% CIs. Qualitative analysis was performed to describe variably reported patient outcomes and the risk of arthrofibrosis after ACLR for noncomparative studies. Results: Screening yielded 6 full-text articles with 448 patients who underwent ACLR (296 ACLR <10 days, 152 ACLR >3 weeks), with a pooled mean age of 28.1 years. For studies amenable to quantitative analysis, there were no significant differences between ACLR performed ≤10 days and ACLR performed at the 3-week point or after in terms of postoperative stiffness (3 studies; odds ratio, 1.27; P = .508), Tegner scores (2 studies; mean difference, –0.056; P = .155), or reoperation for stiffness (3 studies; odds ratio, 0.869; P = .462). The overall incidence of postoperative arthrofibrosis after 12 months of follow-up was 11 of 296 (3.7%) for ACLRs performed ≤10 days versus 6 of 152 (3.9%) for those performed at the 3-week point or after. Conclusion: ACLR performed ≤10 days after the inciting injury does not increase the risk of postoperative arthrofibrosis and demonstrates similar patient-reported outcomes compared with ACLR performed at the 3-week point or after.

After anterior cruciate ligament reconstruction (ACLR), chronic changes in knee joint biomechanics during higher level tasks, such as running, may negatively impact long-term knee joint health. Among the factors that contribute to these chronic changes, the influence of quadriceps strength on knee joint biomechanics during running is not well understood. Higher involved limb quadriceps strength (peak torque and rate of torque development [RTD]) and limb symmetry index (LSI) will be positively associated with greater peak knee flexion angle and peak knee extensor moment during running. Cross-sectional study. Level 3. Peak knee extensor moment and peak knee flexion angle were analyzed during the stance phase of running, 6 months following ACLR (n = 26; 18 female participants; age, 19 ± 5.0 years). Involved limb quadriceps strength and LSI were calculated for peak torque and RTD. Linear regression models were used to analyze the relationship between involved limb and LSI values of quadriceps peak torque and RTD to peak knee flexion angle and peak knee extensor moment. Quadriceps peak torque (R2 = 0.37; P < .01) and RTD (R2 = 0.31, P < .01) each had a positive relationship to peak knee extensor moment, but not peak knee flexion angle. Quadriceps peak torque and RTD LSI were not associated with peak knee flexion angle or peak knee extensor moment (P > .20). Quadriceps peak torque and RTD are positively associated with running kinetics 6 months after ACLR. Peak torque and RTD LSI were not associated with running mechanics after ACLR. Quadriceps peak torque and rate of torque development are positively associated with running mechanics after ACLR. Clinicians should consider objective assessments of quadriceps strength before initiating running after ACLR.

TEMPORAL NEUROMUSCULAR ALTERATIONS OF THE QUADRICEPS AFTER UNILATERAL ANTERIOR CRUCIATE LIGAMENT RECONSTRUCTION Objective: The primary aim of this research was to examine the temporal pattern of neuromuscular quadriceps deficits in both the involved and uninvolved limbs of patients assigned to the control group after anterior cruciate ligament reconstruction (ACLr), by assessing quadriceps strength, voluntary activation, and corticomotor excitability prior to surgery (baseline), three months after ACLr, and six months after ACLr. A secondary aim of this research was to determine whether quadriceps strength, voluntary activation, and/or corticomotor excitability assessed in patients prior to ACLr and/or at three months after surgery, is predictive of lower extremity postural control and/or self-reported function at six months after ACLr. Lastly, a tertiary aim of this research was to determine if a 12week home-based neuromuscular electrical stimulation (Home-NMES) program elicits greater bilateral improvements in quadriceps strength, voluntary activation, and corticomotor excitability of patients at three and six months after ACLr compared to a 12-week standard home-exercise program (control group). Participants: Fifty patients scheduled to undergo unilateral ACLr were randomly allocated to the home-NMES group (19 Female, 6 Male; age: 18.9 ± 5.4 years; height: 170.8 ± 9.7 cm; weight: 74.6 ± 18.5 kg; 28.0±20.0 days-post-injury) or control group (14 Female, 11 Male; age: 19.4 ± 4.5 years; height: 171.1 ± 11.5 cm; weight: 70.7 ± 11.9 kg). Methods: A randomized clinical trial design was used in this study. Prior to ACLr, isometric quadriceps strength and voluntary quadriceps activation were assessed in both limbs of patients, and corticomotor excitability was assessed in the involved limb. Three days after ACLr, both groups were instructed to begin their allocated interventions. The Home-NMES group administered NMES to their involved limb’s quadriceps three sessions a day for 15 minutes, and five days a week for 12 weeks using a portable NMES device. The control group was treated according to the current standard-of-care, but they were also instructed to perform volitional isometric quadriceps contractions for the same duration and frequency as the Home-Based NMES protocol. The outcomes measures were reassessed in both groups at three and six months post-ACLr. Main Outcome Measures: Quadriceps strength and voluntary activation were assessed using maximal voluntary isometric contractions and the superimposed burst technique, respectively. Normalized

Therapeutic approaches to treat joint contracture after anterior cruciate ligament (ACL) reconstruction have not been established. Arthrofibrosis accompanied by joint inflammation following ACL reconstruction is a major cause of arthrogenic contracture. In this study, we examined whether anti-inflammatory treatment using low-level laser therapy (LLLT) can prevent ACL reconstruction-induced arthrogenic contracture. Rats underwent ACL transection and reconstruction surgery in their right knees. Unoperated left knees were used as controls. After surgery, rats were reared with or without daily LLLT (wavelength: 830 nm; power output: 150 mW; power density: 5 W/cm2; for 120 s/day). We assessed the passive extension range of motion (ROM) after myotomy at one and two weeks post-surgery; the reduction in ROM represents the severity of arthrogenic contracture. ROM was markedly decreased by ACL reconstruction at both time points; however, LLLT partially attenuated the decrease in ROM. One week after ACL reconstruction, the gene expression of the proinflammatory cytokine interleukin-1beta in the joint capsule was significantly upregulated, and this upregulation was significantly attenuated by LLLT. Fibrotic changes in the joint capsule, including upregulation of collagen type I and III genes, shortening of the synovium, and thickening were caused by ACL reconstruction and seen at both time points. LLLT attenuated these fibrotic changes as well. Our results indicate that LLLT after ACL reconstruction could attenuate the formation of arthrogenic contracture through inhibition of inflammation and fibrosis in the joint capsule. Thus, LLLT may become a novel therapeutic approach for ACL reconstruction-induced joint contracture.

Objectives:The incidence of anterior cruciate ligament (ACL) injuries continues to rise,and meniscal injuries are commonly associated with these tears. Treatment ofmeniscal injuries can impart delayed weightbearing range-of-motionrestrictions, which can affect the post-operative rehabilitation protocol.These limitations after a meniscal repair could change how patients aremanaged and progressed through rehab. The effect of the meniscal treatmentand subsequent restrictions on strength recovery after ACL reconstruction(ACLR) is unclear and may affect return-to-play assessments. The purpose ofthis study was to compare strength, jumping performance and patient reportedoutcomes between isolated ACLR patients and those undergoing surgicalintervention for meniscal pathology at the time of ACLR surgery at ascheduled functional testing assessment an average of 6 months aftersurgery. Our hypothesis is that those undergoing meniscal repair will havelower strength recovery due to post-operative restrictions.Methods:In this retrospective cohort study, ACLR patients and healthy controlscompleted patient-reported outcomes (IKDC and KOOS), underwent bilateralisokinetic and isometric strength tests of the knee extensor and flexorgroups, as well as functional hop testing as part of a return-to-sport testbattery at 5-7 months post-operatively. ACLR patients were stratified asisolated ACLR, ACLR+Meniscectomy (ACLR-MS), ACLR+Meniscal Repair (ACLR-MR)and compared to healthy controls. Patients treated with meniscus repair wererestricted to partial weight bearing and to 90 degrees of knee flexion forthe first 6 weeks post-surgery. Comparisons were performed between meniscaltreatment groups with regard to demographics, patient reported outcomesscales, knee extensor and flexor strength, while stratifying by grafttype.Results:305 participants, including 165 ACLR patients (50 isolated ACLR, 71 ACLR +Meniscal Repair, 44 ACLR + Meniscectomy) and 140 healthy controls wereincluded with an average time post-operatively to functional testing of5.96±0.47 months. Heathy controls demonstrated higher subjective kneefunction, unilateral peak extensor torque, and limb symmetry than allmeniscal subgroups (p<.001). There were no differences between the IKDC,KOOS subscales, or in unilateral or limb symmetry measures of peak kneeextensor or flexor torque between ACLR, ACLR+MS, and ACLR+MR patients (allp-values>.05).Conclusions:Persistent weakness, asymmetry and reduced subjective outcome scores measuredat approximately 6 months post index surgery were not influenced by meniscustreatment. Knee flexor and extensor strength, limb symmetry, and patientreported outcomes did not significantly differ across patients undergoingisolated ACLR, ACL + Meniscus Repair, and ACL + meniscectomy. These findingssuggest that the weightbearing and range-of-motion restrictions associatedwith meniscus repair recovery do not result in loss of early strength orpatient reported outcomes, and they can be progressed through therapyaccordingly.

Performance symmetry between limbs (limb symmetry index [LSI] ≥ 90%) on a battery of single-leg hop tests is recommended to inform return-to-sport (RTS) decisions after anterior cruciate ligament (ACL) reconstruction (ACLR). Achieving current hop test symmetry values has not been associated with future clinical outcomes. The identification of age-relevant and activity-relevant target values to benchmark the hop test performance of young athletes post-ACLR may provide greater specificity and clinical relevance for interpretation of hop test data. To identify single-leg hop test-target values for individual-limb performance and symmetry between limbs for athletes without a history of ACL injury and evaluate the proportion of young athletes post-ACLR who met the newly derived target values at the time of RTS clearance. The secondary objective was to test the hypothesis that better function and strength would be associated with achieving the newly derived hop test target values. Cross-sectional study. Pediatric medical center and academic medical center. A total of 159 young athletes (age = 16.9 ± 2.2 years) at the time of RTS clearance after primary, unilateral ACLR and 47 uninjured control athletes (age = 17.0 ± 2.3 years). All participants completed a single-leg hop test battery (single hop, triple hop, and crossover hop for distance [cm], and 6-m timed hop [seconds]). Raw distance values were normalized by body height, and LSI (%) was calculated for each hop test. Target values were defined as the lower bound of the 95% CI for each hop test, using control group data. Participants with ACLR also completed the Knee injury and Osteoarthritis Outcome Score subscales and a quadriceps femoris strength (newton meters/kilogram) assessment. Logistic regression determined predictors of achieving hop test target values in the ACLR group among injury, function, and strength data (P < .05). In the ACLR group, 79% to 84% of participants met the 90% LSI threshold on each hop test. They achieved the target values for surgical-limb performance in the following proportions (% participants): single hop = 29%, triple hop = 24%, crossover hop = 30%, 6-m timed hop = 18%, all hops= 12%. Also, they met the target values for LSI in the following proportions: single hop = 43%, triple hop = 48%, crossover hop = 50%, 6-m timed hop = 69%, all hops = 25%. The only predictor of achieving all hop test targets for surgical-limb performance was greater surgical-limb quadriceps femoris strength (odds ratio = 4.10, P = .007). We noted a trend toward quadriceps femoris strength LSI ≥ 90% (odds ratio = 2.44, P = .058) as a predictor for meeting all hop test symmetry targets. At the time of RTS post-ACLR, only a small proportion of young athletes achieved the age-relevant and activity-relevant single-leg hop test targets for surgical-limb performance or symmetry between limbs, even though a majority met the traditionally recommended 90% LSI threshold on hop tests.

Preoperative and Intraoperative Predictors of Long-Term Acceptable Knee Function and Osteoarthritis After Anterior Cruciate Ligament Reconstruction: An Analysis Based on 2 Randomized Controlled Trials

Rehabilitation is one of the most critical points after anterior cruciate ligament (ACL) reconstruction. However, the recent trend of low-cost, short-term hospitalization makes sufficient rehabilitation after ACL reconstruction difficult. 34 patients who underwent non-anatomical single bundle ACL reconstruction using a hamstring auto graft were evaluated. Twenty patients (12 males and 8 females) were transferred to a special rehabilitation hospital (RH hospital group) after operation and concentrated rehabilitation was performed up to 4 h per day. Fourteen (9 males and 5 females) patients performed clinic-based rehabilitation at a university hospital three times per week (clinic group). Strength of quadriceps and knee flexion muscles was assessed at 60 degrees /s using a Cybex II dynamometer (Lumex, Ronkonkoma, NY, USA) at 3, 6 and 9 months after ACL reconstruction. Anterior tibial translation (ATT) and pivot shift test were also evaluated. No significant difference in muscle recovery in the lower extremity was observed at any time point after ACL reconstruction between the clinic group and the RH hospital group. However, 3 months after operation, the average muscle strength of the RH hospital group tended to be higher than that of the clinic group. There was no significant difference in ATT or pivot shift (each group included 4 positive pivot shift subjects) in the patients who were tested between the clinic group and the RH hospital group. Concentrated rehabilitation at a rehabilitation hospital after ACL reconstruction has the potential to improve muscle strength in the lower extremities more dramatically in the early stages of post operation. However, the initial benefits of intensive physiotherapy disappear after 6 months.

The relationship between quadriceps strength asymmetry and knee biomechanics asymmetry during walking in individuals with anterior cruciate ligament reconstruction

Background: Surgeons and health care systems have received a call to action in an effort to curtail the current opioid epidemic. Purpose: To (1) define the natural history of opioid demand after anterior cruciate ligament reconstruction (ACLR), (2) consider how filling preoperative opioid prescriptions affects opioid demand after ACLR, and (3) evaluate the effect of additional procedures during ACLR and patient age on postoperative opioid demand. Study Design: Cohort study; Level of evidence, 3. Methods: ACLRs performed in the Humana database between 2007 and 2014 were identified using Current Procedural Terminology code 29888. Patients were considered preoperative opioid users if they had filled an opioid prescription in the 3 months preceding surgery. Patients were defined as “chronic” opioid users if they had filled a prescription preoperatively at 1 to 3 months from surgery. Further categorization was performed by identifying patients who only underwent ACLR with no other procedures, those who underwent ACLR with meniscus repair, those who underwent ACLR with meniscectomy, and those who underwent ACLR with microfracture. Categorization by age was also performed. The relative risk (RR) of postoperative opioid use was calculated, and 95% CIs were determined. Results: Over the course of the study period, 4946 ACLRs were performed. At 3 months after their procedure, 7.24% of patients were still filling opioid prescriptions. At 9 and 12 months postoperatively, 4.97% and 4.71% of patients, respectively, were still filling opioid prescriptions. Nearly 35% of patients (1716/4946) were filling opioid pain prescriptions in the 3 months before ACLR. Those filling preoperative opioid prescriptions were 5.35 (95% CI, 4.15-6.90) times more likely to be filling opioid prescriptions at 3 months after ACLR than nonusers (15.38% vs 2.88%, respectively). Those filling opioid prescriptions chronically before surgery were at a 10.50 (95% CI, 7.53-14.64) times increased risk of filling postoperative opioid prescriptions at 5 months. At 5 months postoperatively, patients undergoing ACLR with microfracture had a 1.96 (95% CI, 1.34-2.87) increased risk of filling opioid prescriptions compared with ACLR alone, 2.38 (95% CI, 1.48-3.82) increased risk compared with ACLR with meniscus repair, and 1.51 (95% CI, 1.04-2.19) increased risk compared with ACLR with meniscectomy. Patients younger than 25 years of age had an increased risk of filling opioid prescriptions after ACLR at all time points of the study. Conclusion: Opioid demand after ACLR dropped significantly in the vast majority of patients by the third postoperative month. Surprisingly, 35% of patients undergoing ACLR were observed to be using opioid medication preoperatively, and this study found preoperative opioid use to be a strong predictor of postoperative opioid demand with a 5- to 7-fold increased risk in this patient population. Patients who were filling opioid prescriptions 1 to 3 months from their surgical date were at the highest risk for postoperative opioid utilization. Patients undergoing ACLR with microfracture were at an increased risk of filling opioid prescriptions. Patients less than 25 years of age were at an elevated risk of filling opioid prescriptions at all time points postoperatively.

There has been increased interest in lateral extra-articular procedures, such as anterolateral ligament reconstruction (ALLR) or lateral extra-articular tenodesis (LET), to reduce anterolateral rotation instability of the knee after anterior cruciate ligament reconstruction (ACLR). Despite promising surgical outcomes with these techniques, their impact on knee strength recovery is unknown. Patients undergoing lateral extra-articular procedures at the time of ACLR would have impaired thigh muscle strength at 6 to 9 months after surgery. Cohort study; Level of evidence, 3. Adolescent patients who had undergone primary unilateral ACLR with lateral extra-articular augmentation between 2017 and 2023 were identified. Patients were included if they were aged between 12 and 20 years at the time of surgery and had completed an isokinetic strength assessment at 6 to 9 months after surgery. A total of 104 participants (mean age, 16.5 ± 1.7 years; 63 female) were included in this analysis: 25 who underwent ACLR+ALLR, 17 who underwent ACLR+LET, and 62 who underwent isolated ACLR. Isokinetic knee extension and flexion strength normalized to body weight, as well as the bilateral limb symmetry index (LSI), were assessed. One-way analysis of variance and analysis of covariance were used to compare differences between surgical techniques. After adjusting for age, graft type, and time since surgery, the ACLR+LET (1.36 ± 0.52 N·m/kg) and ACLR+ALLR (1.61 ± 0.53 N·m/kg) groups had significantly less involved limb knee extension strength (P = .025), uninvolved limb knee extension strength (P = .046), and LSI for knee extension strength (P = .040) compared to the isolated ACLR group. There were no differences between the 3 groups regarding involved limb knee flexion strength (P = .222) or uninvolved limb knee flexion strength (P = .984), but the isolated ACLR group displayed a greater LSI for knee flexion strength (96.6% ± 17.8%; P = .012). The addition of lateral extra-articular procedures at the time of ACLR was associated with decreased quadriceps strength at 6 to 9 months after ACLR. While lateral extra-articular procedures may enhance knee rotary stability after ACLR, prolonged rehabilitation may be needed to re-establish adequate quadriceps strength before return to sports.

Background: Loss of motion (LOM) remains a common complication after anterior cruciate ligament (ACL) reconstruction and can be detrimental to patient outcomes after surgery. LOM is multifactorial, but nonsurgical and surgical solutions to this complex problem are available. A paucity of quality data exists evaluating clinical outcomes after the surgical treatment of patients with LOM after ACL reconstruction. Hypothesis: Patients undergoing surgical lysis of adhesions and manipulation under anesthesia for LOM after ACL reconstruction will exhibit decreased function, lower outcome scores, and delayed time of release to play when compared with matched controls without LOM. Study Design: Cohort study; Level of evidence, 3 Methods: A database of 1572 patients undergoing ACL reconstruction was sampled from 2013 to 2017 to identify a total of 58 patients (LOM group [n = 29] vs matched control group [n = 29]). Group comparisons were examined for patients requiring a second surgical procedure for LOM versus matched controls after ACL reconstruction for differences in surgical timing, self-reported International Knee Disability Committee scores, objective function at release to play, and subjective knee function at 2 years with the Single Assessment Numeric Evaluation. The risk of a type I error was set at α = .05 for all statistical analyses. Results: Patients who underwent lysis of adhesions and manipulation under anesthesia for LOM after ACL reconstruction exhibited no differences in Single Assessment Numeric Evaluation knee function at 2 years when compared with matched controls (85.8 ± 14.9 vs 88.0 ± 10.8, P = .606). All patients met release-to-play criteria. Only International Knee Disability Committee scores (P = .046) and single-legged hop testing (P = .050) reached statistically significant differences, with higher scores in the control group. There was no difference in the time to release to play (P = .034) or level of participation (P = .180) between the control and surgical groups. Subjective function scores at 2 years were not significantly different between groups. Tourniquet time during the index ACL reconstruction was shorter in the control group (P = .034). Conclusion: The findings of this study suggest that patients who undergo surgical treatment for LOM after ACL reconstruction can release to play at similar times but display relative deficits in single-legged-hop symmetry and lower self-reported function when compared with matched controls. Longer surgical times may increase the risk for LOM after ACL reconstruction. Registration: NCT03704376 (ClinicalTrials.gov identifier)

Lateral extra-articular tenodesis (LET) may confer improved rotational stability after anterior cruciate ligament reconstruction (ACLR). Little is known about how LET affects in vivo cartilage contact after ACLR. The aim of this study was to investigate the effect of LET in combination with ACLR (ACLR + LET) on in vivo cartilage contact kinematics compared to isolated ACLR (ACLR) during downhill running. It was hypothesised that cartilage contact area in the lateral compartment would be larger in ACLR + LET compared with ACLR, and that the anterior-posterior (A-P) position of the contact center on the lateral tibia would be more anterior after ACLR + LET than after ACLR. Twenty patients were randomly assigned into ACLR + LET or ACLR during surgery (ClinicalTrials.gov:NCT02913404). At 6months and 12months after surgery, participants were imaged during downhill running using biplane radiography. Tibiofemoral motion was tracked using a validated registration process. Patient-specific cartilage models, obtained from 3T MRI, were registered to track bone models and used to calculate the dynamic cartilage contact area and center of cartilage contact in both the medial and lateral tibiofemoral compartments, respectively. The side-to-side differences (SSD) were compared between groups using a Mann-Whitney U test. At 6months after surgery, the SSD in A-P cartilage contact center in ACLR + LET (3.9 ± 2.6mm, 4.4 ± 3.1mm) was larger than in ACLR (1.2 ± 1.6mm, 1.5 ± 2.0mm) at 10% and 20% of the gait cycle, respectively (p < 0.01, p < 0.05). There was no difference in the SSD in cartilage contact center at 12months after surgery. There was no difference in SSD of cartilage contact area in the medial and lateral compartments at both 6 and 12months after surgery. There were no adverse events during the trial. LET in combination with ACLR may affect the cartilage contact center during downhill running in the early post-operation phase, but this effect is lost in the longer term. This suggests that healing and neuromuscular adaptation occur over time and may also indicate a dampening of the effect of LET over time. (337 /350 words) LEVEL OF EVIDENCE: Level II.