Osteoarthritis prevalence following anterior cruciate ligament reconstruction: a systematic review and numbers-needed-to-treat analysis

Bone Marrow Aspirate Concentrate Augmentation May Accelerate Allograft Ligamentization in Anterior Cruciate Ligament Reconstruction: A Double-Blinded Randomized Controlled Trial

PURPOSE

To assess the effect of bone marrow aspiration concentrate (BMAC) augmentation on clinical outcomes and magnetic resonance imaging (MRI) findings in anterior cruciate ligament (ACL) reconstruction (ACLR) with bone-patellar tendon-bone (BTB) allografts.

METHODS

A double-blinded, randomized controlled trial was conducted on 80 patients undergoing ACL reconstruction using BTB allografts. Patients were randomized to 2 groups: (1) bone marrow aspirate was collected from the iliac crest, concentrated, and approximately 2.5 mL was injected into the BTB allograft, or (2) a small sham incision was made at the iliac crest (control). MRI was performed at 3 months and 9 months postoperatively to determine the signal intensity ratio of the ACL graft.

RESULTS

Seventy-three patients were available for follow-up at 1-year postoperatively (36 BMAC, 37 control). International Knee Documentation Committee (IKDC) scores were significantly greater in the BMAC group versus the control at the 9-month postoperative period (81.6 ± 10.5 vs 74.6 ± 14.2, P = .048). There was no significant difference in the proportion of patients who met the minimal clinically important difference for IKDC between the BMAC and control groups at 9 months (89% vs 85%; P = .7). Three months postoperatively, signal intensity ratio of the inferior third of the ACL graft was significantly greater in the BMAC group versus the control group (3.2 ± 2.2 vs 2.1 ± 1.5; P = .02).

CONCLUSIONS

Patients who received BMAC augmentation of the BTB allograft during ACL reconstruction demonstrated greater signal intensity scores on MRI at 3 months, suggesting increased metabolic activity and remodeling, and potentially accelerated ligamentization. Additionally, patients in the BMAC group had greater patient-reported outcomes (IKDC) at 9 months postoperatively when compared with those who underwent a standard surgical procedure. There was no significant difference in the proportion of patients who met the minimal clinically important difference for IKDC between the BMAC and control groups at 9 months, suggesting limited clinical significance at this time point.

LEVEL OF EVIDENCE

I, randomized control trial.

Shear strain and inflammation-induced fixed charge density loss in the knee joint cartilage following ACL injury and reconstruction: A computational study

Excessive tissue deformation near cartilage lesions and acute inflammation within the knee joint after anterior cruciate ligament (ACL) rupture and reconstruction surgery accelerate the loss of fixed charge density (FCD) and subsequent cartilage tissue degeneration. Here, we show how biomechanical and biochemical degradation pathways can predict FCD loss using a patient-specific finite element model of an ACL reconstructed knee joint exhibiting a chondral lesion. Biomechanical degradation was based on the excessive maximum shear strains that may result in cell apoptosis, while biochemical degradation was driven by the diffusion of pro-inflammatory cytokines. We found that the biomechanical model was able to predict substantial localized FCD loss near the lesion and on the medial areas of the lateral tibial cartilage. In turn, the biochemical model predicted FCD loss all around the lesion and at intact areas; the highest FCD loss was at the cartilage-synovial fluid-interface and decreased toward the deeper zones. Interestingly, simulating a downturn of an acute inflammatory response by reducing the cytokine concentration exponentially over time in synovial fluid led to a partial recovery of FCD content in the cartilage. Our novel numerical approach suggests that in vivo FCD loss can be estimated in injured cartilage following ACL injury and reconstruction. Our novel modeling platform can benefit the prediction of PTOA progression and the development of treatment interventions such as disease-modifying drug testing and rehabilitation strategies.

Changes in Bone Mineral Density of the Femur and Tibia Before Injury to 2 Years After Anterior Cruciate Ligament Reconstruction in Division I Collegiate Athletes

BACKGROUND

Osteoarthritis (OA) is a significant long term concern after anterior cruciate ligament (ACL) reconstruction (ACLR). A low bone mineral density (BMD), particularly in the subchondral region, has been associated with the development of OA and is evident at the knee in patients long after ACLR. It is unknown if persistent BMD deficits are present in high level collegiate athletes.

PURPOSE/HYPOTHESIS

The purpose of this study was to evaluate bilateral changes in the BMD of the femur and tibia from before the injury to 24 months after ACLR in collegiate athletes. We hypothesized that the BMD of both the distal femur and the proximal tibia would be significantly reduced within the surgical limb initially postoperatively but return to preinjury levels by 24 months after ACLR.

STUDY DESIGN

Cohort study; Level of evidence, 2.

METHODS

A total of 33 Division I collegiate athletes were identified between 2010 and 2021 (13 female) who underwent total body dual-energy X-ray absorptiometry (DXA) before sustaining an ACL injury. DXA was repeated at 6, 12, and 24 months after ACLR. Linear mixed effects models assessed differences in the BMD at 5%, 15%, and 50% of the femur's length (F₅, F₁₅, F₅₀) and at 5%, 15%, and 50% of the tibia's length (T₅, T₁₅, T₅₀) within each limb from before the injury to 24 months after ACLR, reported as Tukey-adjusted P values.

RESULTS

Compared with before the injury, the BMD at F₅ of the surgical limb was reduced by 0.15 g/cm² (SE, 0.02 g/cm²) at 6 months (P < .001). The BMD at F₁₅ of the surgical limb was reduced by 0.06 g/cm² (SE, 0.01 g/cm²), 0.09 g/cm² (SE, 0.01 g/cm²), and 0.09 g/cm² (SE, 0.01 g/cm²) at 6, 12, and 24 months, respectively (all P < .001). The BMD at T₅ of the nonsurgical limb was reduced by 0.07 g/cm² (SE, 0.02 g/cm²) at 12 months (P = .02) and 0.10 g/cm² (SE, 0.02 g/cm²) at 24 months (P = .001). The BMD at T₁₅ of the surgical limb was reduced by 0.07 g/cm² (SE, 0.01 g/cm²) at 6 months and 0.08 g/cm² (SE, 0.02 g/cm²) at 12 months (P < .001).

CONCLUSION

BMD deficits at F₁₅ of the surgical limb persisted out to 24 months (-7.1%) after ACLR compared with before the injury in collegiate athletes. The BMD at F₅ and T₁₅ of the surgical limb was reduced at 6 and 12 months but not at 24 months compared with preinjury levels. For the nonsurgical limb, no significant differences were detected, except for the T₅ region at 12 months (-5.1%) and 24 months (-7.2%). The BMD at F₅₀ and T₅₀ of both limbs was not significantly different than preinjury levels at any time after ACLR.

Correlation of Cruciate Ligament Histological Findings with Coronal Plane Deformities and Characteristics of Patients Undergoing Total Knee Arthroplasty

Introduction:Osteoarthritis (OA) is a leading cause of disability in older adults. The majority of cruciate ligament injuries progress to OA through numerous mechanisms. The aim of this study was to identify the histological changes of cruciate ligaments in OA knees from patients undergoing total knee arthroplasty (TKA) as well as possible correlations with coronal plate deformities and patients' characteristics. Methods:A total of 50 consecutive patients with knee OA undergoing TKA with posterior stabilized prosthesis were included in the study. Demographics, preoperative range of flexion, the flexion contracture, Visual Analogue Scale (VAS) score, coronal plane deformity, Kellgren and Lawrence radiological degree of OA and Beguin-Locker classification of intraoperative degree of OA were recorded. The histopathological changes evaluated in specimens from both cruciate ligaments included myxoid and mucoid degeneration, chondroid metaplasia and orientation of collagen fibers. Results:A total of 24 males (48%) and 26 females (52%) with a mean age of 71 years (SD 5.93) participated in our study. The mean preoperative duration of pain was 3.62 years (SD 2.2). The K-L scale mean score was 2.60 (SD 0.64) and the mean VAS score 6.38 (SD 1.1). The mean varus deformity was 10.14 degrees (SD 3.7). Knee flexion/flexion contracture were recorded at 95.76±6.183 and 16.14±4.914 degrees, respectively. Intraoperatively, the B-L scale mean score was 2.02 (SD 0.77). Mucoid degeneration in ACL was the most common histopathological feature (15.7%) (SD 12.9), followed by chondroid metaplasia in both ACL and PCL [14.3% (SD12.5) and 14.3% (SD 13.2), respectively]. A negative correlation between BMI and myxoid ACL (p=0.01) as well as between varus deformity and mucoid ACL (p=0.05) was found, while a negative correlation between height and myxoid ACL (p=0.05) has been also revealed. Conclusion:Degeneration of cruciate ligaments is associated with degenerative joint disease and OA should be considered a disease involving the whole joint including ligaments, menisci, synovium and joint capsule. However, the correlation between degeneration of cruciate ligaments and OA is not yet fully understood and more research is needed.

Comparison of the knee joint reaction force between individuals with and without acute anterior cruciate ligament rupture during walking

Background

Anterior cruciate ligament plays a significant role in knee joint stability. It is claimed that the incidence of knee osteoarthritis increases in individuals with anterior cruciate ligament (ACL) rupture. The aim of this study was to evaluate the knee joints reaction force in ACL rupture group compared to normal subjects.

Method

Fifteen patients with acute ACL rupture and 15 healthy subjects participated in this study. The ground reaction force (GRF) and kinematic data were collected at a sampling rate of 120 Hz during level-ground walking. Spatiotemporal parameters, joint angles, muscle forces and moments, and joint reaction force (JRF) of lower extremity were analyzed by OpenSIM software.

Results

The hip, knee and ankle joints reaction force at loading response and push-off intervals of the stance phase during walking was significantly higher in individuals with ACL rupture compared to healthy controls (p value < 0.05). Walking velocity (p value < 0.001), knee (p value = 0.065) and ankle (p value = 0.001) range of motion in the sagittal plane were significantly lower in the patients with ACL rupture compared to healthy subjects. The mean value of vertical GRF in the mid-stance, the peak of the hip adduction moment in loading response and push-off phases, the hip abductor, knee flexor and vastus intermedius part of quadriceps muscle forces were significantly higher compared to healthy subjects (p < 0.05) while vastus medialis and vastus lateralis produced significantly lower force (p < 0.001).

Conclusions

Based on results of this study, lower limb JRF was higher in those with ACL rupture compared to healthy subjects may be due to the compensatory mechanisms used by this group of subjects. An increase in knee JRF in patients with ACL rupture may be the reason for the high incidence of knee OA.

Validating a Semi-Automated Technique for Segmenting Femoral Articular Cartilage on Ultrasound Images

OBJECTIVE

To validate a semi-automated technique to segment ultrasound-assessed femoral cartilage without compromising segmentation accuracy to a traditional manual segmentation technique in participants with an anterior cruciate ligament injury (ACL).

DESIGN

We recruited 27 participants with a primary unilateral ACL injury at a pre-operative clinic visit. One investigator performed a transverse suprapatellar ultrasound scan with the participant's ACL injured knee in maximum flexion. Three femoral cartilage ultrasound images were recorded. A single expert reader manually segmented the femoral cartilage cross-sectional area in each image. In addition, we created a semi-automatic program to segment the cartilage using a random walker-based method. We quantified the average cartilage thickness and echo-intensity for the manual and semi-automated segmentations. Intraclass correlation coefficients (ICC_2,k) and Bland-Altman plots were used to validate the semi-automated technique to the manual segmentation for assessing average cartilage thickness and echo-intensity. A dice correlation coefficient was used to quantify the overlap between the segmentations created with the semi-automated and manual techniques.

RESULTS

For average cartilage thickness, there was excellent reliability (ICC_2,k = 0.99) and a small mean difference (+0.8%) between the manual and semi-automated segmentations. For average echo-intensity, there was excellent reliability (ICC_2,k = 0.97) and a small mean difference (-2.5%) between the manual and semi-automated segmentations. The average dice correlation coefficient between the manual segmentation and semi-automated segmentation was 0.90, indicating high overlap between techniques.

CONCLUSIONS

Our novel semi-automated segmentation technique is a valid method that requires less technical expertise and time than manual segmentation in patients after ACL injury.

Prevalence of Early Knee Osteoarthritis Illness Among Various Patient-Reported Classification Criteria After Anterior Cruciate Ligament Reconstruction

OBJECTIVE

To compare the prevalence of participants meeting different patient-reported criteria for early osteoarthritis (OA) illness after anterior cruciate ligament reconstruction (ACLR).

METHODS

Participants completed the Knee Injury and Osteoarthritis Outcomes Score (KOOS) at a single time point 5.0-7.9 months post-ACLR. We used established KOOS subscale criteria (i.e., Luyten original and Englund original) to define patient-reported early OA illness. A two-by-two contingency table and McNemar's test were used to compare the prevalence of participants who met the Luyten original versus Englund original KOOS criteria for early OA illness. These analyses were repeated using KOOS subscale thresholds based on established population-specific patient acceptable symptom state (PASS) within the Luyten and Englund KOOS criteria (i.e., Luyten PASS and Englund PASS).

RESULTS

A greater prevalence of participants with ACLR met the Luyten original criteria (n = 165 [54%]) compared to those who met the Englund original criteria (n = 128 [42%]; χ2  = 19.3, P < 0.001). When using the KOOS subscale PASS as thresholds, a significantly greater prevalence of participants with ACLR met the Luyten PASS criteria (n = 133 [43%]) compared to those who met the Englund PASS criteria (n = 85 [28%]; χ2  = 48.0, P < 0.001). When combining the Luyten and Englund KOOS criteria and using the original/PASS subscale thresholds, respectively, 40%/57% of participants met neither, 24%/15% met only 1, and 36%/28% met both KOOS criteria.

CONCLUSION

Regardless of the classification criteria used to define early OA illness, it is concerning that 28-54% of patients report considerable symptoms ~6 months post-ACLR. Our findings will improve the classification criteria to define early OA illness, which may raise awareness for the need of population-specific criteria.

Anterior Cruciate Ligament Injury and Knee Osteoarthritis: An Umbrella Systematic Review and Meta-analysis

OBJECTIVE

To conduct a systematic review of reviews to summarize the (1) risk for development and (2) prevalence of knee osteoarthritis (OA) after anterior cruciate ligament (ACL) injury and surgical treatment and (3) compare prevalence rates between surgical and nonsurgical treatment of ACL injury.

DATE SOURCES

Five electronic databases were searched using medical subject heading and text words up to February 2020 to identify English language reviews.

STUDY SELECTION

Studies were included if they were a systematic review or meta-analysis.

DATA EXTRACTION

Thirteen eligible reviews were included, and the main outcome extracted was knee OA prevalence or risk data and any meta-analysis results.

DATA SYNTHESIS

Results from reviews were combined with a summary meta-analysis based on odds ratios (ORs) or proportions. There was a near 7-fold and 8-fold increase in the odds for the development of knee OA post ACL injury [OR = 6.81 (5.70-8.13)] and ACL reconstruction [OR = 7.7, (6.05-9.79)]. Data were too heterogenous to specify a point estimate prevalence for OA after ACL injury, but OA prevalence was estimated at 36% (19.70-53.01) at near 10 years after reconstruction surgery. A significantly higher prevalence of OA was found for those who received surgical treatment at a minimum 10-year follow-up [OR = 1.40 (1.17-1.68)].

CONCLUSIONS

This study combines all data from previous systematic reviews into a single source to show that ACL injury markedly increases the risk for development of knee OA, which is likely to be present in the long term in approximately a third of patients who have reconstruction surgery. Surgical treatment does not reduce OA prevalence in the longer term compared with nonsurgical treatment.

Comparison of Anterior Cruciate Ligament Tears Treated Nonoperatively Versus With Reconstruction: Risk of Subsequent Surgery

BACKGROUND

Anterior cruciate ligament (ACL) tears can be devastating injuries, leading to joint instability, meniscal tears, and subsequent arthritis. It is unknown whether ACL reconstruction (ACLR) alters the natural history of joint degeneration in the ACL-deficient knee compared with nonoperative treatment, and few studies have examined outcomes in middle-aged patients.

PURPOSE

The objective of this study was to compare the midterm risk of subsequent ipsilateral knee surgery in middle-aged patients after an ACL injury treated with initial conservative (nonoperative) management (CM) versus ACLR (operative management [OM]) within 6 months of the diagnosis.

STUDY DESIGN

Cohort study; Level of evidence, 3.

METHODS

We performed an electronic database search from 2011 to 2012 for all patients aged 35 to 55 years with an initial diagnosis of magnetic resonance imaging-confirmed ACL tear. Patients who elected CM and those who underwent ACLR within 6 months of the diagnosis (OM) were identified. Index patient and clinical characteristics were collected from the health record. All patients were longitudinally observed until August 31, 2017. The primary outcome was subsequent ipsilateral knee surgeries, and secondary outcomes included contralateral knee surgeries, deep surgical-site infections, and venous thrombotic events.

RESULTS

The mean follow-up was 4.8 ± 0.6 years. The CM group included 463 patients (40.2%) and the OM group included 690 patients (59.8%). The mean ages were 43.9 ± 5.7 years and 42.7 ± 5.3 years for patients in the CM and OM groups, respectively (P < .001). Obesity and smoking were significantly more common in the CM group. During the follow-up, 180 patients (38.9%) in the CM group underwent subsequent ipsilateral knee surgery compared with 73 (10.6%) patients in the OM group (P < .001). The mean time to the first ipsilateral procedure was 0.9 ± 1.1 years in the CM and 2 ± 1.5 years in the OM group (P < .001). Delayed ipsilateral ACLRs were performed in 81 patients in the CM group (17.5%); non-ACLR ipsilateral knee surgeries were performed in 156 patients in the CM group (33.7%). Contralateral knee surgery rates were similar. In a regression model, after controlling for age, sex, the Charlson Comorbidity Index score, and smoking status, it was found that normal body mass index and CM group were risk factors for undergoing subsequent knee surgery or ipsilateral non-ACLR surgery.

CONCLUSION

Excluding delayed ACLR, subsequent ipsilateral knee surgeries were more common and occurred earlier in middle-aged patients with nonoperatively managed ACL tears compared with patients managed with reconstruction.

Serum Cartilage Oligomeric Matrix Protein Detects Early Osteoarthritis in Patients With Anterior Cruciate Ligament Deficiency

PURPOSE

To investigate the ability of serum cartilage oligomeric matrix protein (COMP) to detect early osteoarthritis (OA) (International Cartilage Research Society [ICRS] grade 1 or 2 cartilage lesions) in patients with anterior cruciate ligament (ACL)-deficient patients.

METHODS

Patients with an ACL injury of Kellgren-Lawrence grade 0 or 1 were enrolled. Serum samples for COMP measurement were obtained before surgery. The cartilage surfaces of 6 compartments were classified using the ICRS grading system. The patients were divided into groups with and without early OA according to the cartilage findings and diagnostic criteria for early OA.

RESULTS

In total, 98 patients (mean age 23.7 years; range 12 to 49) were included, with 30 patients (30.6%) in the early OA group and 68 (69.4%) in the no early OA group. The 2 groups significantly differed in age, body mass index, preoperative Tegner activity scale, and serum COMP level. The cutoff value of serum COMP for the presence of early OA arthroscopic cartilage lesions was 152.0 ng/mL. Multiple logistic regression analysis revealed age (odds ratio 1.09; 95% confidence interval [CI] 1.02 to 1.16; P = .01) and serum COMP (odds ratio 1.02; 95% CI 1.01 to 1.04; P < .001) to be independent factors for the presence of early OA arthroscopic cartilage findings.

CONCLUSIONS

The incidence of early OA arthroscopic cartilage findings was ∼30% in patients with ACL deficiency, and serum COMP levels were significantly higher in the early OA group than in the no early OA group. The optimum cutoff value for serum COMP was 152 ng/mL. Serum COMP can be used to detect early cartilage change in patients with ACL deficiency.

LEVEL OF EVIDENCE

Ⅲ, retrospective comparative study.

Aberrant gait biomechanics in individuals with ACL reconstruction are magnified during treadmill walking

Aberrant gait biomechanics following anterior cruciate ligament reconstruction (ACLR) likely contribute to post-traumatic osteoarthritis (PTOA) development. Gait biomechanics are typically assessed overground, but the use of instrumented/force-measuring treadmills is increasingly common. The purpose of this study was to compare gait biomechanics overground and on an instrumented treadmill in individuals with ACLR and healthy controls. Twenty-four individuals with ACLR and 24 healthy controls completed overground and gait biomechanics assessments. Biomechanical outcomes included peak vertical ground reaction force (vGRF), internal knee extension (KEM) and abduction (KAM) moments, and knee flexion (KFA) and adduction angles; KFA at heel strike; knee flexion displacement; and inter-limb symmetry for each outcome. Peak KEM (P < 0.001, 95%CI [-0.016, -0.007 xBW*Ht]) and vGRF (P < 0.001, 95%CI [-0.09. -0.03 xBW]) were significantly less symmetrical in the ACLR group compared to the control group on the treadmill but not overground. Additionally, peak KEM was smaller in the ACLR limb compared to the contralateral limb both overground (P = 0.005, 95%CI [-0.010, -0.001 xBW*Ht]) and on the treadmill (P < 0.001, 95%CI [-0.015, -0.007 xBW*Ht]), but this difference was 1.8x larger on the treadmill compared to overground. Peak KFA (P = 0.001, 95%CI [-4.2, -1.2°]) and vGRF (P < 0.001, 95%CI [-0.07, -0.03 xBW]) were smaller in the ACLR limb on the treadmill but not overground. These findings suggest aberrant gait biomechanics are exacerbated during treadmill walking post-ACLR and that evaluating kinematics and kinetics on instrumented treadmills may be valuable for assessing risk factors of PTOA development.

Skeletal muscle cellular contractile dysfunction after anterior cruciate ligament reconstruction contributes to quadriceps weakness at 6-month follow-up

Muscle dysfunction following anterior cruciate ligament reconstruction (ACLR) may evolve from alterations in muscle contractility at the myofilament protein level. Using a prospective, within-subject case-control design, we evaluated cellular-level contractility, cross-sectional area (CSA), and myosin heavy chain (MHC) isoform expression on single muscle fibers 3 weeks post ACLR, and evaluated their relationship to whole muscle strength and patient-oriented outcomes 6 months post operation. Biopsies of the vastus lateralis were performed 3 weeks post ACLR in 11 subjects (5 females, mean age ± SD = 24.7 ± 6.5 years, height = 172.7 ± 8.2 cm, mass = 75.7 ± 12.5 kg) following first-time ACL rupture and whole muscle strength and self-reported pain, function, and quality of life assessed 6 months post ACLR. At 3 weeks post ACLR, force production was reduced (p < 0.01) in MHC I (-36%) and IIA (-48%) fibers compared with the non-injured leg. When force production was expressed relative to CSA to account for fiber atrophy, reductions remained in MHC IIA fibers (-40%; p < 0.001), but MHC I fibers showed only a trend toward being lower (-13%; p = 0.09). Finally, skeletal muscle fiber functional deficits at 3 weeks post ACLR were associated with whole muscle weakness and less favorable patient-reported outcomes at 6-month follow-up. Thus, ACLR promotes early cellular contractile dysfunction that may contribute to decreased whole muscle strength and patient function, and increased patient-reported symptoms, at 6-month follow-up.

Adolescents Are Less Physically Active Than Adults After Anterior Cruciate Ligament Reconstruction

Background:

Sources of physical activity (PA) and motivation for return to sport after anterior cruciate ligament reconstruction (ACLR) differ between adolescents and adults. It is unclear whether these differences influence participation in PA during the first year after ACLR when individuals are transitioning from rehabilitative care to unrestricted activity.

Purpose:

To compare device-assessed measures of PA between adolescents and adults at 6 to 12 months after ACLR.

Study Design:

Cross-sectional study; Level of evidence, 3.

Methods:

Included were 22 adolescents (age, 15.9 ± 1.2 years; time since surgery = 8.0 ± 2.1 months) and 23 adults (age, 22.5 ± 5.0 years; time since surgery = 8.2 ± 2.1 months) who were cleared for unrestricted PA after primary unilateral ACLR. Participants were considered physically active if they met their age-specific United States Department of Health and Human Services PA guidelines. Participants wore an accelerometer-based PA monitor for at least 7 days. Daily minutes of moderate to vigorous–PA (MVPA) and daily step counts were reported and compared between age groups using analysis of covariance, with monitor wear time and sex included as covariates. The association between age group and meeting age-specific PA guidelines was assessed using binary logistic regression and reported as an odds ratio.

Results:

Adults with ACLR participated in 16 minutes more MVPA per day (49 ± 22 vs 33 ± 16 minutes per day; P < .001) and took 2212 more steps per day (8365 ± 2294 vs 6153 ± 1765 steps per day; P < .001) when compared with adolescent participants. In addition, 83% of adults were physically active, compared with 9% of adolescents (odds ratio = 60.2; 95% CI, 7.6-493.4).

Conclusion:

Adolescents with ACLR were less physically active than adults with ACLR, and only 9% of adolescents met aerobic PA guidelines. This is concerning because PA patterns adopted early in life are predictive of PA patterns in adulthood. Our findings indicate a need to better understand underlying causes of reduced PA among adolescents with ACLR and to develop intervention strategies that promote engagement in adequate PA after rehabilitation.

Arthrogenic Muscle Inhibition Following Anterior Cruciate Ligament Injury

Arthrogenic muscle inhibition (AMI) is a common impairment in individuals who sustain an anterior cruciate ligament (ACL) injury. The AMI causes decreased muscle activation, which impairs muscle strength, leading to aberrant movement biomechanics. The AMI is often resistant to traditional rehabilitation techniques, which leads to persistent neuromuscular deficits following ACL reconstruction. To better treat AMI following ACL injury and ACL reconstruction, it is important to understand the specific neural pathways involved in AMI pathogenesis, as well as the changes in muscle function that may impact movement biomechanics and long-term structural alterations to joint tissue. Overall, AMI is a critical factor that limits optimal rehabilitation outcomes following ACL injury and ACL reconstruction. This review discusses the current understanding of the: (1) neural pathways involved in the AMI pathogenesis following ACL injury; (2) consequence of AMI on muscle function, joint biomechanics, and patient function; and (3) development of posttraumatic osteoarthritis. Finally, the authors review the evidence for interventions specifically used to target AMI following ACL injury.

Is Lever Test Superior to Lachman, Pivot Shift, Drawer Tests in Diagnosing Anterior Cruciate Ligament Injuries?

Introduction: The physical examination in anterior cruciate ligament (ACL) injuries is extremely important, and the Lever test is commonly utilized on ACL evaluation. However, the number and scope of studies on the Lever test is limited. In this prospective cross-sectional study, we aimed to evaluate the effectiveness of the diagnostic values of Lachman, Pivot Shift, Lever, and Anterior Drawer tests in terms of quadriceps atrophy and case phase in ACL injuries.

Methods: In this prospective study, diagnostic values of Lachman, Pivot Shift, Lever, and Anterior Drawer tests were examined on 189 patients with positive MRI results as the gold standard.

Results: Lever test positivity was significantly more frequent in the group with quadriceps atrophy preoperative and after sedation (p<0.05). Anterior Drawer test positivity was significantly more frequent in the group with positive quadriceps atrophy preoperatively, after sedation and after spinal anesthesia (p<0.05). Lever and Anterior Drawer tests were positively correlated with quadriceps atrophy preop and after sedation (p<0.05). Lever test before surgery, after sedation and after spinal anesthesia in the chronic patient group was more positive than in the acute and subacute groups (p<0.05). Lever test was positively correlated with phase preoperatively, after sedation and after spinal anesthesia (p<0.01).

Conclusion: The presence or absence of quadriceps atrophy in patients with acute, sub-acute, or chronic ACL injury has a significant effect on the predictive value of the Lever test. We think that univariate analyzes may give incorrect results when demonstrating predictive value, and it would be more correct to perform multivariate analyzes.

Concurrent Validity and Reliability of Two-dimensional Frontal Plane Knee Measurements during Multi-directional Cutting Maneuvers

BACKGROUND

Excessive knee valgus has been strongly suggested as a contributing key factor for anterior cruciate ligament (ACL) injuries. Three-dimensional (3D) motion analysis is considered the "gold standard" to assess joint kinematics, however, this is difficult for on-field assessments and for clinical setting.

PURPOSE

To investigate the concurrent validity of 2D measurements of knee valgus angle during cutting in different directions and to explore intra-rater and inter-rater reliability of the 2D measurements.

STUDY DESIGN

Descriptive laboratory study.

METHOD

Seven recreational soccer players participated in this study. Participants performed three trials of cutting maneuvers in three different directions (30º, 60º, and 90º) with the dominant leg. Cutting maneuvers were recorded simultaneously with a video camera and a ViconTM motion capture system. Knee valgus angle from 2D and 3D measurements at initial contact and at peak vertical ground reaction force (vGRF) were extracted. The Pearson's correlation was used to explore the relationship between the 2D and 3D measurements, and reliability of the 2D measurements were performed using intraclass correlation coefficients (ICC).

RESULT

Significant correlations between 2D and 3D knee valgus measurements were noted for 60º (r = 0.45) and 90º (r = 0.77) cutting maneuvers at initial contact. At peak vGRF, significant correlations between 2D and 3D knee valgus measurements were noted for 30º, 60º, and 90º cutting maneuvers (r=0.45, r=0.74, r=0.78), respectively. Good-to-excellent intra-rater and inter-rater reliability of the 2D knee valgus measurements was observed during cutting in all directions (ICCs: 0.821-0.997).

CONCLUSION

Moderate-to-strong correlation between 2D and 3D knee valgus measurements during 60°-90° cutting maneuvers, and good-to-excellent intra-rater and excellent inter-rater reliability for the 2D measurements in the present study supports the use of 2D knee valgus measurements in the evaluation of targeted interventions, although the limitations of examining cutting maneuvers using 2D measurement in complex movement still need to be considered.

LEVEL OF EVIDENCE

3.

Prior Anterior Cruciate Ligament Reconstruction Does Not Compromise the Functional Outcomes of Medial Unicompartmental Knee Arthroplasty Although Revision for Progressive Arthritis May Occur Earlier

BACKGROUND

Anterior cruciate ligament (ACL) deficiency is commonly considered a contraindication for unicompartmental knee arthroplasty (UKA). The purpose of this study is to compare the outcomes of UKA after prior ACL reconstruction (rACL cohort) to UKA with an intact native ACL (nACL cohort).

METHODS

Forty-five patients from 3 institutions who underwent medial UKA after prior rACL were matched by age, gender, preoperative function scores, and body mass index to 90 patients who underwent UKA with an intact nACL. Primary outcomes were Knee Injury and Osteoarthritis Outcome Score for Joint Replacement, Oxford Knee Scores, Knee Society Functional Scores, and Kellgren-Lawrence scores in the unresurfaced, lateral tibiofemoral compartment. Secondary outcomes were postoperative complications and the need for revision to TKA.

RESULTS

At a mean of 3.6 years, all PROMs improved significantly with no differences identified between groups. The incidence of revision TKA was similar between cohorts (P = 1.00); however, the mean time to revision for progressive osteoarthritis was 4.0 years in the nACL group and 2.2 years in the rACL group. Twenty percent of rACL patients had a postoperative complication compared to 8% in the nACL group. Despite presenting with a similar degree of lateral arthritis, a greater percentage of patients developed Kellgren-Lawrence scores of ≥3 in the rACL cohort (9%) than in the nACL cohort (0%).

CONCLUSION

A previously reconstructed ACL does not appear to compromise the short-term functional outcomes of UKA; however, there is a higher rate of minor complications and progression of lateral compartment arthritis, which should be considered with patients in the shared decision process.

Osteoarthritis Progression after ACL Reconstruction Was Significantly Higher Than That of the Healthy Contralateral Knees: Long-Term Follow Up Study of Mean 16.4 Years

Background: This study aimed to assess long-term progression of osteoarthritis (OA) after isolated anterior cruciate ligament (ACL) reconstruction in athletes compared to the healthy contralateral side. Methods: The study included 15 patients and 30 knees with a mean age of 40 years (range, 35–46) years, none of whom had had revision surgery or an injury to the contralateral side. The mean follow-up period was 16.4 years (range, 13–22). Clinical and radiographic assessment included the Tegner activity scale (TAS), International Knee Documentation Committee (IKDC) score, Knee injury and Osteoarthritis Outcome Score (KOOS), and Kellgren and Lawrence (KL) grade. The long-term results of the injured knees were compared with the status of the healthy contralateral side and compared with previously published mid-term results of the same cohort of patients. Results: Patients generally remained clinically asymptomatic or mildly symptomatic at final follow-up, which is reflected by a KOOS pain score of 33 points (maximum 36 points) and an IKDC total subjective score of 87% (maximum 100%). There was a significant difference between mid-term and final follow-up in terms of the function score of the IKDC subjective questionnaire (p = 0.031), compartment findings and donor site morbidity of the IKDC functional examination (both p = 0.034), and the total KOOS score (p = 0.047). The KL score indicated significant progression of OA from mid-term to final follow-up in the injured knees (p = 0.004) and healthy contralateral knees (p = 0.014). Mean OA grades of the injured knees were significantly higher compared with the healthy contralateral side (p = 0.006) at final follow-up, and two patients showed moderate to severe signs of OA in the injured knee. Conclusions: Although most patients remained clinically asymptomatic or mildly symptomatic, long-term progression of OA after isolated ACL reconstruction in athletes was significantly higher compared with the healthy contralateral knee.

Vertical ground reaction force 2 years after anterior cruciate ligament reconstruction predicts 10-year patient-reported outcomes

Disruptions in knee biomechanics during walking following anterior cruciate ligament (ACL) injury have been suggested to lead to the development of premature knee osteoarthritis (OA) and to be potential markers of OA risk and targets for intervention. This study investigated if side-to-side differences in early stance peak vertical ground reaction force (vGRF) during walking 2 years after ACL reconstruction are associated with longer-term (10 years post-reconstruction) changes in patient-reported outcomes. Twenty-eight participants (mean age: 28.7 ± 6.4 years) with primary unilateral ACL reconstruction underwent gait analysis for assessment of peak vGRF and completed Knee Injury and Osteoarthritis Outcome Score (KOOS) and International Knee Documentation Committee (IKDC) surveys at 2 years post-surgery (2.2 ± 0.3 years) and completed surveys at follow-up 10 years post-surgery (10.5 ± 0.9 years). Associations between changes (10-2 years) in patient-reported outcomes and between limb-differences in vGRF were assessed with Pearson or Spearman's ρ correlation coefficients and exploratory backwards elimination multiple linear regression analyses. Differences in vGRF between symptomatic progressors and non-progressors were also assessed. The side-to-side difference in vGRF was related to the variability in longer-term changes in patient-reported outcome metrics and distinguished symptomatic progressors from non-progressors. Participants with higher vGRF in the reconstructed (ACLR) limb versus the contralateral limb had worsening of IKDC (R = -0.391, p = 0.040), KOOS pain (ρ = -0.396, p = 0.037), KOOS symptoms (ρ = -0.572, p = 0.001), and KOOS quality of life (R = -0.458, p = 0.014) scores at follow-up. Symptomatic progressors had greater vGRF in the ACLR limb as compared to the contralateral limb at baseline than non-progressors (p = 0.023). These data highlight associations between a simple-to-measure gait metric and the development of long-term clinical symptoms after an ACL injury.

Temporal disruption of neuromuscular communication and muscle atrophy following noninvasive ACL injury in rats

Many patients with anterior cruciate ligament (ACL) injuries have persistent quadriceps muscle atrophy, even after considerable time in rehabilitation. Understanding the factors that regulate muscle mass, and the time course of atrophic events, is important for identifying therapeutic interventions. With a noninvasive animal model of ACL injury, a longitudinal study was performed to elucidate key parameters underlying quadriceps muscle atrophy. Male Long-Evans rats were euthanized at 6, 12, 24, or 48 h or 1, 2, or 4 wk after ACL injury that was induced via tibial compression overload; controls were not injured. Vastus lateralis muscle size was determined by wet weight and fiber cross-sectional area (CSA). Evidence of disrupted neuromuscular communication was assessed via the expression of neural cell adhesion molecule (NCAM) and genes associated with denervation and neuromuscular junction instability. Abundance of muscle RING-finger protein-1 (MuRF-1), muscle atrophy F-box (MAFbx), and 45 s pre-rRNA along with 20S proteasome activity were determined to investigate mechanisms related to muscle atrophy. Finally, muscle damage-related parameters were assessed by measuring IgG permeability, centronucleation, CD68 mRNA, and satellite cell abundance. When compared with controls, we observed a greater percentage of NCAM-positive fibers at 6 h postinjury, followed by higher MAFbx abundance 48 h postinjury, and higher 20S proteasome activity at 1 wk postinjury. A loss of muscle wet weight, smaller fiber CSA, and the elevated expression of run-related transcription factor 1 (Runx1) were also observed at the 1 wk postinjury timepoint relative to controls. There also were no differences observed in any damage markers. These results indicate that alterations in neuromuscular communication precede the upregulation of atrophic factors that regulate quadriceps muscle mass early after noninvasive ACL injury.NEW & NOTEWORTHY A novel preclinical model of ACL injury was used to establish that acute disruptions in neuromuscular communication precede atrophic events. These data help to establish the time course of muscle atrophy after ACL injury, suggesting that clinical care may benefit from the application of acute neurogenic interventions and early gait reloading strategies.

Altered lower extremity biomechanics following anterior cruciate ligament reconstruction during single-leg and double-leg stop-jump tasks: A bilateral total support moment analysis

BACKGROUND

Injury to the anterior cruciate ligament (ACL) can lead to long-lasting biomechanical alterations that put individuals at risk of a second ACL injury. Examining the total support moment may reveal between- and within-limb compensatory strategies.

METHODS

Twenty-six participants who were cleared to return to sport following ACL reconstruction were recruited. Each participant completed the single-leg and double-leg stop jump tasks. These tasks were analyzed using force plates and a 3D motion analysis system. The total support moment was calculated by summing the internal moments of the hip, knee and ankle at peak vertical ground reaction force.

FINDINGS

Internal knee extensor moment was lower in the involved limb compared to the uninvolved for both tasks (17.6%, P = 0.022; 18.4%, P = 0.008). No significant between-limb differences were found for the total support moment. The involved limb exhibited an 18.2% decrease in knee joint contribution (P = 0.01) and a 21.6% increase in ankle joint contribution (P = 0.016) to the total support moment compared to the uninvolved limb in the single-leg stop jump task.

INTERPRETATION

Compensation for the involved knee is likely due to altered biomechanics that redistributes load to the uninvolved knee or to adjacent joints of the same limb. A partial shift in joint contribution from the knee to the ankle during the single-leg stop jump task demonstrates a tendency to decrease load to the knee. Further studies are needed to investigate how these adaptations impact the prevalence of subsequent injury and poor joint health.

Relationship between altered knee kinematics and subchondral bone remodeling in a clinically translational model of ACL injury

Abnormal joint kinematics are commonly reported in the acute and chronic stages of recovery after anterior cruciate ligament (ACL) injury and have long been mechanistically implicated as a primary driver in the development of posttraumatic osteoarthritis (PTOA). Though strongly theorized, it is unclear to what extent biomechanical adaptations after ACL injury culminate in the development of PTOA, as data that directly connects these factors does not exist. Using a preclinical, noninvasive ACL injury rodent model, our objective was to explore the direct effect of an isolated ACL injury on joint kinematics and the pathogenetic mechanisms involved in the development of PTOA. A total of 32, 16-week-old Long-Evans rats were exposed to a noninvasive ACL injury. Marker-less deep learning software (DeepLabCut) was used to track animal movement for sagittal-plane kinematic analyses and micro computed tomography was used to evaluate subchondral bone architecture at days 7, 14, 28, and 56 following injury. There was a significant decrease in peak knee flexion during walking (p < .05), which had a moderate-to-strong negative correlation (r = -.59 to -.71; p < .001) with subchondral bone plate porosity in all load bearing regions of the femur and tibia. Additional comprehensive analyses of knee flexion profiles revealed dramatic alterations throughout the step cycle. This occurred alongside considerable loss of epiphyseal trabecular bone and substantial changes in anatomical orientation. Knee flexion angle and subchondral bone microarchitecture are severely impacted after ACL injury. Reductions in peak knee flexion angle after ACL injury are directly associated with subchondral bone plate remodeling.

Quadriceps muscle volume positively contributes to ACL volume

Females have smaller anterior cruciate ligaments (ACLs) than males and smaller ACLs have been associated with a greater risk of ACL injury. Overall body dimensions do not adequately explain these sex differences. This study examined the extent to which quadriceps muscle volume (VOL_QUAD ) positively predicts ACL volume (VOL_ACL ) once sex and other body dimensions were accounted for. Physically active males (N = 10) and females (N = 10) were measured for height, weight, and body mass index (BMI). Three-Tesla magnetic resonance images of their dominant and nondominant thigh and knee were then obtained to measure VOL_ACL , quadriceps, and hamstring muscle volumes, femoral notch width, and femoral notch width index. Separate three-step regressions estimated associations between VOL_QUAD and VOL_ACL (third step), after controlling for sex (first step) and one body dimension (second step). When controlling for sex and sex plus BMI, VOL_HAM , notch width, or notch width index, VOL_QUAD consistently exhibited a positive association with VOL_ACL in the dominant leg, nondominant leg, and leg-averaged models (p < 0.05). Findings were inconsistent when controlling for sex and height (p = 0.038-0.102). Once VOL_QUAD was included, only notch width and notch width index retained a statistically significant individual association with VOL_ACL (p < 0.01). Statement of Clinical Significance: The positive association between VOL_QUAD and VOL_ACL suggests ACL size may in part be modifiable. Future studies are needed to determine the extent to which an appropriate training stimulus (focused on optimizing overall lower extremity muscle mass development) can positively impact ACL size and structure in young females.

Anterior Cruciate Ligament Reconstruction versus Nonoperative Treatment: Better Function and Less Secondary Meniscectomies But No Difference in Knee Osteoarthritis-A Meta-Analysis

OBJECTIVES

The impact of anterior cruciate ligament (ACL) reconstruction on knee osteoarthritis (OA) is still unclear. The aim of the current meta-analysis was to compare surgical treatment versus nonoperative management of ACL tears to assess the impact of these approaches on knee OA development at a 5 and 10 years of follow-up.

DESIGN

A meta-analysis was performed after a systematic literature search (May 2021) was conducted following the Preferred Reporting Items for Systematic Reviews and Meta-analysis (PRISMA) guidelines. Both randomized and nonrandomized comparative studies with more than 5 years of follow-up were selected. Influence of the treatment was assessed in terms of knee OA development, subjective and objective clinical results, activity level, and risk of further surgeries. Risk of bias and quality of evidence were assessed following the Cochrane guidelines.

RESULTS

Twelve studies matched the inclusion criteria, for a total of 1,004 patients. Level of evidence was rated low to very low. No difference was documented in terms of knee OA development, Tegner score, subjective International Knee Documentation Committee (IKDC), and Lysholm scores. A significant difference favoring the surgical treatment in comparison with a nonsurgical approach was observed in terms of objective IKDC score (P = 0.03) and risk of secondary meniscectomy (P < 0.0001). The level of evidence was considered very low for subjective IKDC, low for knee OA development, objective IKDC, number of secondary meniscectomies, and Lysholm score, and moderate for post-op Tegner score.

CONCLUSIONS

The meta-analysis did not support an advantage of ACL reconstruction in terms of OA prevention in comparison with a nonoperative treatment. Moreover, no differences were reported for subjective results and activity level at 5 and 10 years of follow-up. On the contrary, patients who underwent surgical treatment of their ACL tear presented important clinical findings in terms of better objective knee function and a lower rate of secondary meniscectomies when compared with conservatively managed patents.Protocol Registration: CRD420191156483 (PROSPERO).

Longitudinal Changes in Ultrasound-Assessed Femoral Cartilage Thickness in Individuals from 4 to 6 Months Following Anterior Cruciate Ligament Reconstruction

OBJECTIVE

Diagnostic ultrasound provides a valid assessment of cartilage health that has been used to observe cross-sectional cartilage thickness differences post-ACLR (anterior cruciate ligament reconstruction), but has not been used longitudinally during early recovery post-ACLR.

DESIGN

The purpose of this study was to assess longitudinal changes in femoral cartilage thickness via ultrasound in individuals at 4 to 6 months post-ACLR and compared to healthy controls. Twenty participants (50% female, age = 21.1 ± 5.7 years) completed testing sessions 4 and 6 months post-ACLR. Thirty healthy controls (57% female, age = 20.8 ± 3.8 years) without knee injury history completed 2 testing sessions (>72 hours apart). Femoral cartilage ultrasound images were captured bilaterally in ACLR participants and in the dominant limb of healthy controls during all sessions. Average cartilage thicknesses in the medial, intercondylar, and lateral femoral regions were determined using a semi-automated processing technique.

RESULTS

When comparing cartilage thickness mean differences or changes over time, individuals post-ACLR did not demonstrate between limb differences (P-range = 0.50-0.92), limb differences compared to healthy controls (P-range = 0.19-0.94), or changes over time (P-range = 0.22-0.72) for any femoral cartilage thickness region. However, participants demonstrated cartilage thickening (45%) or thinning (35%) that exceeded minimal detectable change (MDC) from 4 to 6 months post-ACLR, respectively.

CONCLUSIONS

Using MDC scores may help better identify within-subject femoral cartilage thickness changes longitudinally post-ACLR due to bidirectional cartilage thickness changes.

Tibiofemoral articular cartilage composition differs based on serum biochemical profiles following anterior cruciate ligament reconstruction

OBJECTIVE

Biochemical joint changes contribute to posttraumatic osteoarthritis (PTOA) development following anterior cruciate ligament reconstruction (ACLR). The purpose of this longitudinal cohort study was to compare tibiofemoral cartilage composition between ACLR patients with different serum biochemical profiles. We hypothesized that profiles of increased inflammation (monocyte chemoattractant protein-1 [MCP-1]), type-II collagen turnover (type-II collagen breakdown [C2C]:synthesis [CPII]), matrix degradation (matrix metalloproteinase-3 [MMP-3] and cartilage oligomeric matrix protein [COMP]) preoperatively to 6-months post-ACLR would be associated with greater tibiofemoral cartilage T1ρ relaxation times 12-months post-ACLR.

DESIGN

Serum was collected from 24 patients (46% female, 22.1 ± 4.2 years old, 24.0 ± 2.6 kg/m2 body mass index [BMI]) preoperatively (6.4 ± 3.6 days post injury) and 6-months post-ACLR. T1ρ Magnetic Resonance Imaging (MRI) was collected for medial and lateral tibiofemoral articular cartilage at 12-months post-ACLR. A k-means cluster analysis was used to identify profiles based on biomarker changes over time and T1ρ relaxation times were compared between cluster groups controlling for sex, age, BMI, concomitant injury (either meniscal or chondral pathology), and Marx Score.

RESULTS

One cluster exhibited increases in MCP-1 and COMP while the other demonstrated decreases in MCP-1 and COMP preoperatively to 6-months post-ACLR. The cluster group with increases in MCP-1 and COMP demonstrated greater lateral tibial (adjusted mean difference = 3.88, 95% confidence intervals [1.97-5.78]) and femoral (adjusted mean difference = 12.71, 95% confidence intervals [0.41-23.81]) T1ρ relaxation times.

CONCLUSION

Profiles of increased serum levels of inflammation and matrix degradation markers preoperatively to 6-months post-ACLR are associated with MRI changes consistent with lesser lateral tibiofemoral cartilage proteoglycan density 12-months post-ACLR.

Influence of Patient Demographics and Surgical Characteristics on Pass Rates of Return-to-Activity Tests in Anterior Cruciate Ligament-Reconstructed Patients Before Physician Clearance

OBJECTIVE

To identify the frequency of passing return-to-activity tests after anterior cruciate ligament reconstruction (ACLR) and to investigate the influence of patient-specific factors on pass rates. We hypothesized that isolated strength tests would be most difficult to pass and that graft type would be the most influential factor.

DESIGN

Cross-sectional.

SETTING

Laboratory.

PARTICIPANTS

Eighty patients with a history of primary, unilateral ACLR, and 80 healthy controls participated.

INTERVENTIONS

Bilateral isokinetic strength, isometric strength, and single-leg hop tests were recorded during a single visit. The International Knee Documentation Committee (IKDC) Subjective Knee Evaluation measured subjective knee function, and the Tegner Activity Scale measured physical activity level.

MAIN OUTCOME MEASURES

Pass rates were calculated for 3 thresholds of absolute between-limb asymmetry: 0% to 10%, 11% to 15%, and 16% to 20%. Pass rates were compared by sex (male and female), graft type (patellar and hamstrings), meniscal procedure (yes and no), physical activity level (</≥ median Tegner), and time from surgery (</≥ 6 months).

RESULTS

Isokinetic quadriceps strength was consistently most difficult to pass, whereas the 6-meter timed hop and crossover hop tests were easiest. Graft type had the greatest influence on pass rates (isometric quadriceps and hamstring strength, hamstrings-to-quadriceps ratio), followed by time from surgery (6-meter timed hop and crossover hop), physical activity (IKDC), and meniscal procedure (6-meter timed hop).

CONCLUSIONS

Isokinetic quadriceps strength was the most difficult test to pass, and single-leg hop tests were the easiest. Patient-specific factors including graft type, time from surgery, physical activity level, and meniscal procedure may influence the ability to meet return-to-activity criterion after ACLR.

Changes in Infrapatellar Fat Pad Volume 6 to 12 Months After Anterior Cruciate Ligament Reconstruction and Associations With Patient-Reported Knee Function

CONTEXT

Hypertrophy of the infrapatellar fat pad (IFP) in idiopathic knee osteoarthritis has been linked to deleterious synovial changes and joint pain related to mechanical tissue impingement. Yet little is known regarding the IFP's volumetric changes after anterior cruciate ligament reconstruction (ACLR).

OBJECTIVES

To examine changes in IFP volume between 6 and 12 months after ACLR and determine associations between patient-reported outcomes and IFP volume at each time point as well as the volume change over time. In a subset of individuals, we examined interlimb IFP volume differences 12 months post-ACLR.

STUDY DESIGN

Prospective cohort study.

SETTING

Laboratory.

PATIENTS OR OTHER PARTICIPANTS

We studied 26 participants (13 women, 13 men, age = 21.88 ± 3.58 years, body mass index = 23.82 ± 2.21 kg/m2) for our primary aims and 13 of those participants (8 women, 5 men, age = 21.15 ± 3.85 years, body mass index = 23.01 ± 2.01 kg/m2) for our exploratory aim.

MAIN OUTCOME MEASURE(S)

Using magnetic resonance imaging, we evaluated the IFP volume change between 6 and 12 months post-ACLR in the ACLR limb and between-limbs differences at 12 months in a subset of participants. International Knee Documentation Committee subjective knee evaluation (IKDC) scores were collected at 6-month and 12-month follow-ups, and associations between IFP volume and patient-reported outcomes were determined.

RESULTS

The IFP volume in the ACLR limb increased from 6 months (19.67 ± 6.30 cm3) to 12 months (21.26 ± 6.91 cm3) post-ACLR. Greater increases of IFP volume between 6 and 12 months were significantly associated with better 6-month IKDC scores (r = .44, P = .03). The IFP volume was greater in the uninjured limb (22.71 ± 7.87 cm3) than in the ACLR limb (20.75 ± 9.03 cm3) 12 months post-ACLR.

CONCLUSIONS

The IFP volume increased between 6 and 12 months post-ACLR; however, the IFP volume of the ACLR limb remained smaller than that of the uninjured limb at 12 months. In addition, those with better knee function 6 months post-ACLR demonstrated greater increases in IFP volume between 6 and 12 months post-ACLR. This suggests that greater IFP volumes may play a role in long-term joint health after ACLR.

Joint effusion at 6 months is a significant predictor of joint effusion 1 year after anterior cruciate ligament reconstruction

PURPOSE

This study aimed to assess the risk factors for prolonged joint effusion in patients undergoing double-bundle anterior cruciate ligament reconstruction (ACLR).

METHODS

In total, 160 patients who underwent primary ACLR using autograft hamstring between 2015 and 2018 were retrospectively reviewed. Joint effusion was defined as any grade ≥ 2 (range, 0-3) according to the MRI Osteoarthritis Knee Score (MOAKS). Univariate and multivariate logistic regression analyses were performed.

RESULTS

The median age of the patients was 25 years (range 14-68 years) at the time of the surgery; there were 89 women and 71 men. At 1 year, 46 (28.8%) patients experienced knee joint effusion, as defined by the MOAKS. Univariate analysis revealed that age, preoperative Kellgren-Lawrence (K-L) grade, and joint effusion at 6 months were significantly associated with joint effusion at 1 year. In the multivariate analysis, joint effusion at 6 months was significantly associated with joint effusion at 1 year (odds ratio, 68.0; 95% confidence interval, 22.1-209.4). No significant difference in the Lysholm scores was observed between patients with and without joint effusion at 1 year (n.s.).

CONCLUSIONS

Joint effusion at 6 months was significantly associated with joint effusion 1 year after ACLR.

LEVEL OF EVIDENCE

III.

Coronal subluxation of the tibiofemoral joint before and after anterior cruciate ligament reconstruction

Background

Studies have shown that medial subluxation of the tibia occurs after anterior cruciate ligament (ACL) rupture. However, it is unclear whether anterior cruciate ligament reconstruction (ACLR) can correct tibial coronal subluxation.

Purpose

To determine whether the tibia is medially subluxated after ACL rupture, and whether ACLR can correct medial subluxation of the tibia.

Study design

Case series; Level of evidence, 4, Retrospective clinical study.

Methods

The distance of tibial coronal subluxation before and after ACLR surgery was measured in 48 patients with ACL rupture and meniscus injury. Tibiofemoral subluxation was defined as the perpendicular distance between the long axis of the tibia and a second parallel line originating at the most proximal aspect of the femoral intercondylar notch. To determine the long axis of the tibia, two circles separated by 5 cm were centered on the proximal tibia. The proximal circle is 5 cm from the tibial plateau, and the distal circle is 5 cm from the proximal circle. The line passing through the center of the two circles was considered the long axis of the proximal tibia. Care was taken to ensure that each patient lied on the back with their patellae facing upward, to minimize rotational variation among the radiographs. At the same time, 30 patients with simple meniscus injury who underwent arthroscopy during the same period were selected to determine the degree of tibiofemoral coronal subluxation as the baseline value. The changes before and after operation were compared, as well as the differences with the baseline data.

Result

The average follow-up period was 21.2 ± 5.8 months. The average distance of tibial coronal subluxation before ACLR was 5.5 ± 2.1 mm, which was significantly different from that of baseline group (7.3 ± 2.1 mm) (P < 0.001). The tibial subluxation after ACLR was 7.7 ± 2.6 mm, which was significantly different from that before operation (P < 0.001). There was no significant difference in the distance between postoperative tibial subluxation and baseline group (P = 0.472).

Conclusion

The tibia was coronally medially subluxated after ACL rupture. ACLR can correct the medial subluxation of tibia. This finding is helpful in the diagnosis of ACL rupture, and can be used to assess the imaging status of the tibiofemoral joint on the coronal plane during or after ACLR.

[Consequences of anterior cruciate ligament rupture: a systematic umbrella review]

INTRODUCTION

 The treatment of an anterior cruciate ligament rupture is still controversial. In particular, this applies to the question of conservative versus surgical treatment. The answer to this question is often based on consequential damage such as the development of posttraumatic osteoarthritis, secondary damage to the meniscus or cartilage, and participation in sports. If there are significant differences in these parameters between the individual treatment options, the results will be of great importance for the development of evidence-based treatment pathways. Therefore, the aim of this work was to evaluate the development of knee osteoarthritis after rupture of the anterior cruciate ligament and the corresponding treatment (conservative or surgical).

MATERIAL AND METHODS

 To answer the above question, a systematic literature search was conducted in Medline via Pubmed, the Cochrane Library and in CINAHL. Only systematic reviews with a minimum follow-up period of 10 years were included. The search was conducted in January 2020 and updated in January 2021. Investigated cohorts included patients with a rupture of the anterior cruciate ligament who had undergone either conservative or surgical treatment. Osteoarthritis was diagnosed either radiologically (recognized scores) or clinically (pain and impaired function). Appropriate reviews were qualitatively evaluated using the AMSTAR-2 questionnaire.

RESULTS

 The literature research initially identified n = 42 reviews from which 14 reviews were included. After full-text review and qualitative evaluation, only n = 2 systematic reviews remained for evaluation. The results of both papers show imprecise data with a high variability. However, it can be assumed with high probability that the development of osteoarthritis of the knee is increased after a rupture of the anterior cruciate ligament. There is no evidence that the incidence of joint degeneration may be reduced by reconstruction of the anterior cruciate ligament, nor is there a difference when comparing conservative and surgical treatment directly.

CONCLUSION

 Patients with an anterior cruciate ligament rupture are likely to be at a greater risk of developing progressive joint degeneration. A protective effect of cruciate ligament surgery has not been found in the evaluated studies. A general argument in favour of cruciate ligament surgery aiming to achieve a protective effect on hyaline articular cartilage seems obsolete based on the results and should therefore not be used in patient education in the future.

Traumatic joint injury induces acute catabolic bone turnover concurrent with articular cartilage damage in a rat model of posttraumatic osteoarthritis

Assess acute alterations in bone turnover, microstructure, and histomorphometry following noninvasive anterior cruciate ligament rupture (ACLR). Twelve female Lewis rats were randomized to receive noninvasive ACLR or Sham loading (n = 6/group). In vivo μCT was performed at 3, 7, 10, and 14 days postinjury to quantify compartment-dependent subchondral (SCB) and epiphyseal trabecular bone remodeling. Near-infrared (NIR) molecular imaging was used to measure in vivo bone anabolism (800 CW BoneTag) and catabolism (Cat K 680 FAST). Metaphyseal bone remodeling and articular cartilage morphology was quantified using ex vivo μCT and contrast-enhanced µCT, respectively. Calcein-based dynamic histomorphometry was used to quantify bone formation. OARSI scoring was used to assess joint degeneration, and osteoclast number was quantified on TRAP stained-sections. ACLR induced acute catabolic bone remodeling in subchondral, epiphyseal, and metaphyseal compartments. Thinning of medial femoral condyle (MFC) SCB was observed as early as 7 days postinjury, while lateral femoral condyles (LFCs) exhibited SCB gains. Trabecular thinning was observed in MFC epiphyseal bone, with minimal changes to LFC. NIR imaging demonstrated immediate and sustained reduction of bone anabolism (~15%-20%), and a ~32% increase in bone catabolism at 14 days, compared to contralateral limbs. These findings were corroborated by reduced bone formation rate and increased osteoclast numbers, observed histologically. ACLR-injured femora had significantly elevated OARSI score, cartilage thickness, and cartilage surface deviation. ACL rupture induces immediate and sustained reduction of bone anabolism and overactivation of bone catabolism, with mild-to-moderate articular cartilage damage at 14 days postinjury.

Feasibility of a Wearable-Based Physical Activity Goal-Setting Intervention Among Individuals With Anterior Cruciate Ligament Reconstruction

CONTEXT

Individuals with a history of anterior cruciate ligament reconstruction (ACLR) demonstrate persistent reductions in physical activity (PA) volume that are not being addressed during rehabilitation. Currently, it is challenging for clinicians to prescribe exercise interventions that extend beyond in-person rehabilitative care in a manner that is responsive and acceptable to patients.

OBJECTIVE

To investigate the feasibility of using a novel, technology-driven, personalized goal-setting intervention over a 2-month period among young individuals with a history of primary unilateral ACLR.

DESIGN

Single-blinded feasibility study.

SETTING

University community.

PATIENTS OR OTHER PARTICIPANTS

Ten women and 2 men (age = 22.0 ± 3.0 years, time since surgery = 56.0 ± 36.3 months) with a history of primary unilateral ACLR.

INTERVENTION(S)

All participants completed a 28-day PA observation period immediately followed by a 28-day individualized PA goal-setting intervention period delivered via a commercially available PA monitor.

MAIN OUTCOME MEASURE(S)

Primary feasibility outcomes were days of PA monitor wear compliance and days of goal achievement during the intervention period. Participants also completed the Knee Osteoarthritis Outcome Score (KOOS) at study enrollment and after the intervention period, and the individual change in the KOOS Quality of Life subscale was compared with the minimal detectable change (7.2 points).

RESULTS

Average PA monitor wear compliance was 95.5% ± 7.3% during the observation period and 97.7% ± 2.9% during the intervention period. Median goal achievement was 31.5% ± 6.8% during the intervention period. Five participants demonstrated meaningful improvements in the KOOS Quality of Life subscale during the study period.

CONCLUSIONS

Individualized goal setting via mobile technology appears to be a feasible approach to PA promotion. However, based on the low rate of daily goal attainment during the intervention period, continued refinement of this intervention aproach would be beneficial before broad clinical implementation.

Changes in anterior femoral articular cartilage structure in collegiate rugby athletes with and without a history of traumatic knee joint injury following a five-month competitive season

This study aimed to examine anterior femoral cartilage morphology before (pre-season) and after (post-season) a 5-month competitive season in collegiate ruby players with and without a previous history of traumatic injury to ligamentous, meniscus, and/or cartilage structures at the knee joint. Using a prospective cohort design, 42 male collegiate rugby players with a previous history of traumatic intracapsular knee joint injury and 124 players without knee injury history were included in this study. Ultrasonography assessments of anterior femoral cartilage were performed before (pre-season) and following a 5-month athletic season (post-season). Rugby players with a history of traumatic knee joint injury had greater lateral condylar thickness (2.37 ± 0.35 mm, p = 0.03), intercondylar thickness (2.51 ± 0.47 mm, p = 0.03), and partial area (44.67 ± 7.28mm², p = 0.02) compared to control players (lateral = 2.23 ± 0.35 mm, intercondylar = 2.32 ± 0.47 mm, partial area = 41.60 ± 7.26 mm²), regardless of pre-and post-season assessment time points. Pre-season ultrasonography assessment of lateral condylar thickness (2.34 ± 0.47 mm, p = 0.02), medial condylar thickness (2.05 ± 0.43 mm, p = 0.03), and partial area (44.10 ± 9.23 mm², p = 0.001) were significantly greater than the post-season ultrasonography assessment time point (lateral = 2.26 ± 0.43 mm, medial = 1.98 ± 0.43 mm, partial area = 42.17 ± 8.82 mm²), regardless of group membership. Rugby players with a history of intracapsular knee joint injury displayed altered anterior femoral cartilage size via ultrasonography assessments. Regardless of a presence of injury history, collegiate rugby players showed a decrease in cartilage thickness and partial area following a 5-month competitive season.

Pre-Operative Femoral Cartilage Ultrasound Characteristics Are Altered in People Who Report Symptoms at 1 year After Anterior Cruciate Ligament Reconstruction

We assessed whether pre-operative femoral cartilage thickness and echo intensity on ultrasound are different between individuals who are symptomatic (n = 6) and asymptomatic (n = 7) at 1 year after a primary unilateral anterior cruciate ligament (ACL) reconstruction (age, 23 ± 4 y; 31% women, 69% men; body mass index, 24.9 ± 3.7 kg/m²). A pre-operative, bilateral ultrasound assessment was used to quantify average thickness and echo intensity in the medial, middle and lateral femoral trochlear regions. An inter-limb ratio (ACL/contralateral limb) was calculated for average thickness and echo intensity. At 1 y after ACL reconstruction, we operationally defined the presence of symptoms as scoring ≤85% on at least two Knee Injury and Osteoarthritis Outcome Score subscales. Independent-sample t-tests and Cohen's d effect sizes were used to compare ultrasound pre-operative inter-limb ratios between participants with and without symptoms at 1 y after ACL reconstruction. For medial femoral cartilage, symptomatic participants had significantly greater average cartilage thickness inter-limb ratios (p = 0.01, d = -1.65) and significantly lower echo intensity inter-limb ratios (p = 0.01, d = 1.72) compared with asymptomatic participants. Middle and lateral femoral cartilage average thickness and echo intensity were not different between symptomatic and asymptomatic participants. These findings provide preliminary evidence that a clinically feasible ultrasound assessment of the femoral trochlear cartilage may be prognostic of self-reported symptoms at 1 y after ACL reconstruction.

Synovial fluid concentrations of matrix Metalloproteinase-3 and Interluekin-6 following anterior cruciate ligament injury associate with gait biomechanics 6 months following reconstruction

OBJECTIVE

To compare gait biomechanics 6 months following anterior cruciate ligament (ACL) reconstruction (ACLR) between patients with the highest and lowest concentrations of synovial fluid (SF) interleukin-6 (IL-6) and matrix metalloproteinase-3 (MMP-3), as well as compared to uninjured controls.

DESIGN

SF concentrations of IL-6 and MMP-3 were collected 7 ± 4 days post injury in 38 ACL injured patients (55% female, 21±4yrs, 25.3 ± 5.2BMI). ACL injured individuals were stratified into the lowest and highest quartiles based on IL-6 (IL-6_Lowest and IL-6_Highest) and MMP-3 (MMP-3_Lowest and MMP-3_Highest) concentrations. Gait biomechanics were collected on the injured limb 6 months post-ACLR and in 38 uninjured controls (50% female, 21±3yrs, 23.8 ± 2.8BMI). Functional analyses of variance were used to compare vertical ground reaction force (vGRF), knee flexion angle (KFA), and internal knee extension moment (KEM) waveforms throughout stance phase of gait to determine the proportions of stance differing between limbs and groups.

RESULTS

Compared to uninjured controls, IL-6_High and MMP-3_High ACL subgroups demonstrated lesser vGRF (largest differences: IL-6, 7.88%BW; MMP-3, 11.05%BW) during early-stance and greater vGRF (largest differences: IL-6, 6.21%BW; MMP-3, 5.85%BW) in mid-stance, lesser KFA (largest differences: IL-6, 3.11°; MMP-3, 3.72°) and lesser KEM (largest differences: IL-6, 0.96%BW•m; MMP-3, 1.07%BW•m) in early-stance, as well as greater KFA in mid-stance (largest differences: IL-6, 1.5°; MMP-3, 2.95°).

CONCLUSIONS

High SF concentrations of a proinflammatory cytokine and a degradative enzyme early post-ACL injury are associated with aberrant gait biomechanics in the injured limb at 6 months post-ACLR (i.e., lesser vGRF, KFA and KEM) linked to posttraumatic osteoarthritis development.

A Systematic Review of Basic Science and Animal Studies on the Use of Doxycycline to Reduce the Risk of Posttraumatic Osteoarthritis After Anterior Cruciate Ligament Rupture/Transection

BACKGROUND

Posttraumatic osteoarthritis (PTOA) after injury to the anterior cruciate ligament (ACL) is common.

PURPOSE

To perform a systematic review of basic science and animal studies to determine the effect of doxycycline treatment on the prevention of PTOA after ACL rupture/transection.

STUDY DESIGN

Systematic review.

METHODS

A systematic review was performed by searching the PubMed, Cochrane Library, and Embase databases to identify basic science and animal studies evaluating the effect of doxycycline treatment on the prevention of PTOA of the knee joint after ACL/cranial cruciate ligament (CCL) injury. The search phrase used was "doxycycline cruciate ligament." Inclusion criteria were basic science and animal studies evaluating the effect of oral administration of doxycycline in ACL/CCL-deficient animals with or without a control group.

RESULTS

Seven studies met inclusion criteria and were included in this systematic review. Five studies were performed in dogs, 1 in rabbits, and 1 in mice. Overall, the effects of doxycycline treatment on the prevention of PTOA after ACL/CCL rupture/transection were mixed. In dogs, no significant effects of doxycycline treatment were found in terms of matrix metalloproteinase (MMP) activity, while a mouse study found significantly lower MMP-13 expression on the tibia in doxycycline-treated animals, suggesting that doxycycline may protect against proteoglycan loss and decrease osteoarthritis progression. Cartilage nitric oxide concentrations were lower in doxycycline-treated dogs compared with untreated dogs, suggesting decreased cartilage degradation among doxycycline-treated dogs, although there were no significant effects on cartilage stromelysin levels with no significant effects in terms of physiological remodeling or catabolism of cartilage. Bone formation or resorption was not found to be affected by doxycycline treatment. One study demonstrated a substantial beneficial effect of doxycycline on gross morphology of the medial femoral condyle. Doxycycline was found to conserve bone strain energy density and appeared to limit subchondral bone loss in 1 study.

CONCLUSION

Based on the limited available animal studies, doxycycline appears to demonstrate some benefits in the prevention of PTOA after ACL/CCL rupture/transection. Additional studies are needed to further characterize the potential benefits, side effects, dosage, and duration of this treatment after ACL injury in human patients.

Association of Jump-Landing Biomechanics With Tibiofemoral Articular Cartilage Composition 12 Months After ACL Reconstruction

BACKGROUND

Excessively high joint loading during dynamic movements may negatively influence articular cartilage health and contribute to the development of posttraumatic osteoarthritis after anterior cruciate ligament reconstruction (ACLR). Little is known regarding the link between aberrant jump-landing biomechanics and articular cartilage health after ACLR.

PURPOSE/HYPOTHESIS

The purpose of this study was to determine the associations between jump-landing biomechanics and tibiofemoral articular cartilage composition measured using T1ρ magnetic resonance imaging (MRI) relaxation times 12 months postoperatively. We hypothesized that individuals who demonstrate alterations in jump-landing biomechanics, commonly observed after ACLR, would have longer T1ρ MRI relaxation times (longer T1ρ relaxation times associated with less proteoglycan density).

STUDY DESIGN

Cross-sectional study; Level of evidence, 3.

METHODS

A total of 27 individuals with unilateral ACLR participated in this cross-sectional study. Jump-landing biomechanics (peak vertical ground-reaction force [vGRF], peak internal knee extension moment [KEM], peak internal knee adduction moment [KAM]) and T1ρ MRI were collected 12 months postoperatively. Mean T1ρ relaxation times for the entire weightbearing medial femoral condyle, lateral femoral condyle (global LFC), medial tibial condyle, and lateral tibial condyle (global LTC) were calculated bilaterally. Global regions of interest were further subsectioned into posterior, central, and anterior regions of interest. All T1ρ relaxation times in the ACLR limb were normalized to the uninjured contralateral limb. Linear regressions were used to determine associations between T1ρ relaxation times and biomechanics after accounting for meniscal/chondral injury.

RESULTS

Lower ACLR limb KEM was associated with longer T1ρ relaxation times for the global LTC (ΔR 2 = 0.24; P = .02), posterior LTC (ΔR 2 = 0.21; P = .03), and anterior LTC (ΔR 2 = 0.18; P = .04). Greater ACLR limb peak vGRF was associated with longer T1ρ relaxation times for the global LFC (ΔR 2 = 0.20; P = .02) and central LFC (ΔR 2 = 0.15; P = .05). Peak KAM was not associated with T1ρ outcomes.

CONCLUSION

At 12 months postoperatively, lower peak KEM and greater peak vGRF during jump landing were related to longer T1ρ relaxation times, suggesting worse articular cartilage composition.

Serum cartilage oligomeric matrix protein is correlated with quantitative magnetic resonance imaging and arthroscopic cartilage findings in anterior cruciate ligament deficient knees without osteoarthritic changes

INTRODUCTION/OBJECTIVES

To investigate the association between serum biomarker [cartilage oligomeric matrix protein (COMP) and matrix metalloproteinase-3 (MMP-3)] levels and clinical, magnetic resonance imaging (MRI), and arthroscopic findings in anterior cruciate ligament (ACL)-deficient knees without osteoarthritic changes on radiographs.

METHOD

Patients with ACL injury of Kellgren-Lawrence grade 0 or 1 were enrolled. Serum COMP and MMP-3 levels were measured preoperatively. Correlations of serum biomarker levels with age, body mass index (BMI), duration from time of injury, Tegner activity scale (TAS) score, Lysholm knee score, International Knee Documentation Committee score, KT-1000 arthrometer measurements, whole-organ MRI score (WORMS), MRI T2 relaxation time, and arthroscopic International Cartilage Research Society (ICRS) grade were assessed by calculating Spearman correlation coefficients. Associations between intraoperative findings (cartilage, meniscus) and serum biomarker levels were determined using the Mann-Whitney U test. Multiple regression analysis was performed to investigate the correlations between serum biomarker levels and MRI and arthroscopic findings.

RESULTS

Ninety-eight patients with a mean age of 23.7 years were enrolled. Higher serum COMP level was correlated with older age and higher BMI, TAS score, serum MMP-3 level, WORMS, and T2 relaxation times (medial femur, medial tibia). Multivariate analysis showed that the serum COMP level was independently associated with WORMS and ICRS grade.

CONCLUSIONS

The serum COMP level was correlated with age, BMI, TAS score, and MMP-3 level in ACL-deficient knees and was independently correlated with WORMS and ICRS grade. Thus, the serum COMP level can help detect cartilage degeneration even in patients without radiographic osteoarthritic changes. Key Points • Serum COMP correlated with WORMS and ICRS grade in ACL deficient knee. • The serum COMP level could help in detecting cartilage degeneration, even in patients with no radiographic osteoarthritic changes.

Ankle Dorsiflexion Affects Hip and Knee Biomechanics During Landing

BACKGROUND

Restricted ankle dorsiflexion range of motion (DFROM) has been linked to lower extremity biomechanics that place an athlete at higher risk for injury. Whether reduced DFROM during dynamic movements is due to restrictions in joint motion or underutilization of available ankle DFROM motion is unclear.

HYPOTHESIS

We hypothesized that both lesser total ankle DFROM and underutilization of available motion would lead to high-risk biomechanics (ie, greater knee abduction, reduced knee flexion).

STUDY DESIGN

Cross-sectional study.

LEVEL OF EVIDENCE

Level 3.

METHODS

Nineteen active female athletes (age, 20.0 ± 1.3 years; height, 1.61 ± 0.06 m; mass, 67.0 ± 10.7 kg) participated. Maximal ankle DFROM (clinical measure of ankle DFROM [DF-CLIN]) was measured in a weightbearing position with the knee flexed. Lower extremity biomechanics were measured during a drop vertical jump with 3-dimensional motion and force plate analysis. The percent of available DFROM used during landing (DF-%USED) was calculated as the peak DFROM observed during landing divided by DF-CLIN. Univariate linear regressions were performed to identify whether DF-CLIN or DF-%USED predicted knee and hip biomechanics commonly associated with injury risk.

RESULTS

For every 1.0° less of DF-CLIN, there was a 1.0° decrease in hip flexion excursion (r² = 0.21, P = 0.05), 1.2° decrease in peak knee flexion angles (r² = 0.37, P = 0.01), 0.9° decrease in knee flexion excursion (r² = 0.40, P = 0.004), 0.002 N·m·N^-1·cm^-1 decrease in hip extensor work (r² = 0.28, P = 0.02), and 0.001 N·m·N^-1·cm^-1 decrease in knee extensor work (r² = 0.21, P = 0.05). For every 10% less of DF-%USED, there was a 3.2° increase in peak knee abduction angles (r² = 0.26, P = 0.03) and 0.01 N·m·N^-1·cm^-1 lesser knee extensor work (r² = 0.25, P = 0.03).

CONCLUSION

Lower levels of both ankle DFROM and DF-%USED are associated with biomechanics that are considered to be associated with a higher risk of sustaining injury.

CLINICAL RELEVANCE

While total ankle DFROM can predict some aberrant movement patterns, underutilization of available ankle DFROM can also lead to higher risk movement strategies. In addition to joint specific mobility training, clinicians should incorporate biomechanical interventions and technique feedback to promote the utilization of available motion.

Conversion rates and timing to total knee arthroplasty following anterior cruciate ligament reconstruction: a US population-based study

PURPOSE

To define the rate of subsequent TKA following ACLR in a large US cohort and to identify factors that influence the risk of later undergoing TKA after ACLR.

METHODS

The California's Office of Statewide Health Planning and Development (OSHPD) database was queried from 2000 to 2014 to identify patients who underwent primary ACLR (ACL group). An age-and gender-matched cohort that underwent appendectomy was selected as the control group. The cumulative incidence of TKA was calculated and ten-year survival was investigated using Kaplan-Meier analysis with failure defined as conversion to arthroplasty. Univariate and multivariate analyses were performed to explore the risk factors for conversion to TKA following ACLR.

RESULTS

A total of 100,580 ACLR patients (mean age 34.48 years, 66.1%male) were matched to 100,545 patients from the general population. The ACL cohort had 1374 knee arthroplasty events; conversion rate was 0.71% at 2-year follow-up, 2.04% at 5-year follow-up, and 4.86% at 10-year follow-up. This conversion rate was higher than that of the control group at all time points, with an odds ratio of 3.44 (p<0.001) at 10-year follow-up. Decreasing survivorship following ACLR was observed with increasing age, female gender, and worker's compensation insurance, while increased survivorship was found in patients of Hispanic and Asian Pacific Islander racial heritage and those who underwent concomitant meniscal repair.

CONCLUSIONS

In this US statewide study, the rate of TKA after ACLR is higher than reported elsewhere, with significantly increased odds when compared to a control group. Age, gender, concomitant knee procedures and other socioeconomic factors influence the rate of conversion to TKA following ACLR.

Incorporating Internal and External Training Load Measurements in Clinical Decision Making After ACL Reconstruction: A Clinical Commentary

BACKGROUND AND PURPOSE

Poor outcomes after anterior cruciate ligament reconstruction (ACLr), including the relatively high risk of suffering a subsequent ACL injury, suggest the need to optimize rehabilitation and return-to-sport testing. The purpose of this commentary is to introduce clinicians to the concept of monitoring training load during rehabilitation, to review methods of quantifying internal and external loads, and to suggest ways that these technologies can be incorporated into rehabilitation progressions and return-to-sport decisions after anterior ACLr.

DESCRIPTION OF TOPIC WITH RELATED EVIDENCE

Quantifying and identifying the effects of training load variables, external (distance, impacts, decelerations) and internal (heart rate, heart rate variability) workload, during rehabilitation can indicate both positive (improved physical, physiological, or psychological capacity) or negative (heightened risk for injury or illness) adaptations and allow for the ideal progression of exercise prescription. When used during return-to-sport testing, wearable technology can provide robust measures of movement quality, readiness, and asymmetry not identified during performance-based testing.

DISCUSSION / RELATION TO CLINICAL PRACTICE

Researchers have reported the actual in-game demands of men and women of various ages and competition levels during multi-directional sport. Wearable technology can provide similar variables during rehabilitation, home exercise programs, and during on-field transition back to sport to ensure patients have met the expected fitness capacity of their sport. Additionally, clinicians can use internal load measures to objectively monitor patient's physiological responses to rehabilitation progressions and recovery rather than relying on subjective patient-reported data.

LEVEL OF EVIDENCE

5.

Long-term gait biomechanics in level, uphill, and downhill conditions following anterior cruciate ligament reconstruction

BACKGROUND

Altered gait biomechanics have been linked to post-traumatic knee osteoarthritis development following anterior cruciate ligament reconstruction surgery, but the persistence of aberrant gait biomechanics after the first year post-surgery is inconsistent in the literature. Gait biomechanics are typically evaluated on a level surface, but this task may not elucidate discrepancies in individuals further removed from surgery due to the simplicity of the task. Graded surfaces are common in real-world ambulation and may exacerbate aberrant gait biomechanics due to greater mechanical demands.

METHODS

Forty-seven individuals post-anterior cruciate ligament reconstruction (4 ± 3 years post-surgery) and forty-seven uninjured controls completed gait analysis under level, uphill, and downhill conditions on an instrumented treadmill. Outcomes included knee flexion displacement and peak knee flexion angle, vertical ground reaction force, and knee extension and abduction moments.

FINDINGS

Knee extension moment and knee flexion displacement were lesser in the surgical limb compared to the contralateral during the downhill condition, with lesser knee flexion displacement also observed during the level condition. Additionally, knee extension moment was less symmetrical in the surgical group during both uphill and downhill conditions compared to controls. Knee flexion displacement was less symmetrical in the surgical group during both level and downhill conditions compared to controls.

INTERPRETATION

Graded surfaces elucidate aberrant gait biomechanics in individuals more than 1 year post-anterior cruciate ligament reconstruction that are not apparent during level walking. These findings suggest that gait assessment on level surfaces may mask existing deficiencies, and warrant emphasizing ambulation of graded surfaces during anterior cruciate ligament rehabilitation.

Association between Kinesiophobia and Gait Asymmetry after ACL Reconstruction: Implications for Prevention of Reinjury

Gait asymmetries have been documented in individuals after anterior cruciate ligament (ACL) reconstruction (ACLR). The relationship between gait asymmetry and associated psychological factors, however, is not yet known. This study aimed to examine the relationship between kinesiophobia (fear of reinjury) and asymmetry of vertical ground reaction force (vGRF) and lower-extremity muscular activity in individuals after ACLR during gait. Twenty-eight males with a history of ACLR participated in the study. Force plate and surface electromyography was used to record peak vGRF and muscular activity. The Tampa Scale of Kinesiophobia (TSK-11) was used to measure kinesiophobia. Spearman’s rank correlations analysis was used to examine the relationship between TSK-11 scores and both gait asymmetry variables. There was a significant positive relationship between TSK-11 and asymmetry of the second peak of vGRF (r_s = 0.531, p = 0.002). In addition, there was a significant positive association between asymmetry of rectus femoris activity (r_s = 0.460, p = 0.007) and biceps femoris activity (r_s = 0.429, p = 0.011) in the contact phase. Results revealed a significant relationship between kinesiophobia and asymmetry in muscle activity and vGRF in different phases of the gait cycle. Interventions addressing kinesiophobia early in the rehabilitation after ACLR may support the restoration of gait symmetry, facilitate a more rapid return to sport, and reduce the risk of ACL reinjury.

Lower medial hamstring activity after ACL reconstruction during running: a cross-sectional study

Objective

Anterior cruciate ligament reconstruction (ACLR) predisposes footballers for subsequent ACL and hamstring (HS) injury. This case series examines HS muscle activation patterns during the running in ACLR patients (bone-patellar tendon-bone (BTB) and (HS) graft) after completion of functional criteria allowing return to training.

Methods

Electromyography (EMG) recorded from medial and lateral HS bilaterally during treadmill running (12, 14 and 16 km/hour) from 21 male ACLR patients on average 7 months from surgery (5-9) that underwent (HS) (n=12) or BTB reconstruction (n=9) were compared with 19 healthy runners. Main outcome measures: EMG signal was normalised to peak during the running. Pairwise comparisons were made for each muscle group examining stance and swing activation for mean and peak EMG for each patient group and leg.

Results

Significantly lower relative peak activation in stance (not swing) phase for medial HS was seen for all conditions with effect sizes ranging from −0.63 (controls, BTB non-injured leg) to −1.09 (HS injured). For lateral HS only BTB injured were significantly lower in stance phase (−1.05)

Conclusion

ACLR patients show neuromuscular alterations during different phases of running. The finding of reduced medial HS activity in stance phase might have implications for knee instability and HS muscle injury on resumption of sport.

Hamstrings Neuromuscular Function After Anterior Cruciate Ligament Reconstruction: A Systematic Review and Meta-Analysis

BACKGROUND

Hamstrings neuromuscular function is a crucial component of functional movement, and changes after anterior cruciate ligament (ACL) injury contribute to risk factors for secondary injury and long-term sequelae. To effectively treat muscular impairments, an accurate understanding of hamstrings neuromuscular function in patients with ACL reconstruction (ACLR) is needed.

OBJECTIVE

A systematic review and meta-analysis were undertaken to describe and quantify hamstrings neuromuscular function in individuals with ACLR compared to controls.

METHODS

We searched PubMed, Web of Science, SPORTDiscus, CINAHL, and EBSCOhost databases in October of 2020 for studies evaluating the difference between hamstrings electromyography (EMG) between individuals with ACLR and controls. Two independent reviewers assessed each paper for inclusion and quality. Means and standard deviations were extracted from each included study to allow random-effect size (ES) meta-analysis calculations for comparison of results.

RESULTS

Thirty-four studies were included for final review. From these, 5 categories of neuromuscular outcomes were identified, and studies were grouped accordingly: (1) muscle activation levels (EMG amplitude), (2) co-activation, (3) onset timing, (4) electromechanical delay, and (5) time-to-peak activity. Moderate to strong evidence indicates that individuals with ACLR demonstrate higher hamstrings EMG amplitude (normalized to % maximum voluntary isometric contraction) and hamstrings-to-quadriceps co-activation during gait and stair ambulation compared to controls. In addition, there was moderate evidence of longer electromechanical delay during knee flexion and greater hamstrings-to-quadriceps co-activation during knee extension compared to controls.

CONCLUSIONS

Greater hamstrings EMG amplitude and co-activation during gait and ambulation tasks and longer electromechanical delay of the hamstrings in individuals with ACLR align with clinical impairments following ACLR and have implications for re-injury risk and long-term joint health, thus warranting attention in rehabilitation.

Mid-term outcomes of anterior cruciate ligament reconstruction across age groups: A national database study

Background

The purpose of this study was to examine the impact of age on complication risk after anterior cruciate ligament reconstruction.

Methods

The TriNetX research database was retrospectively queried for patients undergoing primary arthroscopic ACL reconstruction. Univariate logistic regression was performed to evaluate the risk of complication by age group.

Results

A total of 21,449 patients were included in the study. Patients ≥61 years old demonstrated significantly higher rates of repeat reconstruction. Rates of postoperative opioid related disorders and surgical site infection varied by age.

Conclusion

For patients undergoing ACL reconstruction, increasing age is associated with increased risk of developing opioid related disorders, and repeat reconstruction.

Fibrin-Based Biomaterial Systems to Enhance Anterior Cruciate Ligament Healing

Anterior cruciate ligament (ACL) tears are a common and potentially career-ending injury, particularly for athletes and soldiers. Partial and complete ruptures of this ligament cause instability in the knee, and the ACL does not have the capacity for healing due, in part, to its position within the highly thrombolytic synovial fluid environment of the knee joint. Traditional methods of ACL reconstruction, such as graft replacement with attached bone anchors for bone integration, restore stability, but do not prevent the development of post-traumatic osteoarthritis. To enhance therapeutic treatment options, novel fibrin-based technologies and repair techniques have been recently explored and show promise for improved patient outcomes. Through modification of existing surgical methods, such as the use of fibrin glues incorporating growth factors and cells and the implementation of scaffolds containing platelet-rich plasma, platelet-rich fibrin, and other blood derivatives, surgeons are attempting to overcome the shortcomings of traditional treatments. This mini-review will detail current efforts using fibrin-based treatments and discuss opportunities to further enhance ACL healing.

Neuromuscular Function of the Knee Joint Following Knee Injuries: Does It Ever Get Back to Normal? A Systematic Review with Meta-Analyses

BACKGROUND

Neuromuscular deficits are common following knee injuries and may contribute to early-onset post-traumatic osteoarthritis, likely mediated through quadriceps dysfunction.

OBJECTIVE

To identify how peri-articular neuromuscular function changes over time after knee injury and surgery.

DESIGN

Systematic review with meta-analyses.

DATA SOURCES

PubMed, Web of Science, Embase, Scopus, CENTRAL (Trials).

ELIGIBILITY CRITERIA FOR SELECTING STUDIES

Moderate and high-quality studies comparing neuromuscular function of muscles crossing the knee joint between a knee-injured population (ligamentous, meniscal, osteochondral lesions) and healthy controls. Outcomes included normalized isokinetic strength, muscle size, voluntary activation, cortical and spinal-reflex excitability, and other torque related outcomes.

RESULTS

A total of 46 studies of anterior cruciate ligament (ACL) and five of meniscal injury were included. For ACL injury, strength and voluntary activation deficits were evident (moderate to strong evidence). Cortical excitability was not affected at < 6 months (moderate evidence) but decreased at 24+ months (moderate evidence). Spinal-reflex excitability did not change at < 6 months (moderate evidence) but increased at 24+ months (strong evidence). We also found deficits in torque variability, rate of torque development, and electromechanical delay (very limited to moderate evidence). For meniscus injury, strength deficits were evident only in the short-term. No studies reported gastrocnemius, soleus or popliteus muscle outcomes for either injury. No studies were found for other ligamentous or chondral injuries.

CONCLUSIONS

Neuromuscular deficits persist for years post-injury/surgery, though the majority of evidence is from ACL injured populations. Muscle strength deficits are accompanied by neural alterations and changes in control and timing of muscle force, but more studies are needed to fill the evidence gaps we have identified. Better characterisation and therapeutic strategies addressing these deficits could improve rehabilitation outcomes, and potentially prevent PTOA.

TRIAL REGISTRATION NUMBER

PROSPERO CRD42019141850.

Influence of Anticipation and Motor-Motor Task Performance on Cutting Biomechanics in Healthy Men

CONTEXT

Biomechanical analyses of cutting tasks have demonstrated kinematic differences associated with the noncontact knee-injury risk when the movement direction is unanticipated. Motor-motor dual tasks occur within dynamic environments and change the demand for attentional resources needed to complete athletic maneuvers, which may contribute to injury risk.

OBJECTIVE

To investigate the influence of anticipation and motor-motor task performance on cutting biomechanics.

DESIGN

Cross-sectional study.

SETTING

Laboratory.

PATIENTS OR OTHER PARTICIPANTS

A total of 32 healthy, recreationally active men (age = 23.1 ± 3.6 years, height = 180.0 ± 7.0 cm, mass = 81.3 ± 17.3 kg) who self-reported regular participation in cutting sports.

INTERVENTION(S)

Participants performed a 45° side-step cut on the dominant limb in a random order of conditions: anticipation (anticipated, unanticipated) and task (no ball throw, ball fake, ball throw).

MAIN OUTCOME MEASURE(S)

Triplanar trunk, hip, and knee angles were assessed throughout the stance phase using 3-dimensional motion capture. Data were analyzed using a time series of means calculated from initial contact to toe-off (0%-100%) with 90% confidence intervals. Mean differences between conditions were identified as regions of nonoverlapping confidence intervals, and those that occurred during the region of peak vertical ground reaction force (0%-25%) are presented.

RESULTS

Regardless of anticipation, attending to a ball (ball throw) resulted in more trunk extension (range = 2.9°-3.7°) and less lateral trunk flexion toward the cutting direction (range = 5.2°-5.9°). Planning to attend to a ball (ball fake) resulted in less lateral trunk flexion toward the cutting direction (4.7°). During unanticipated cutting, more trunk rotation away from the cutting direction was observed when attending to a ball (range = 5.3°-7.1°). The interaction of anticipation and task had a similar influence on sagittal- and frontal-plane trunk position.

CONCLUSIONS

Motor-motor task performance and its interaction with anticipation induced an upright, neutral trunk position during side-step cutting, which has been associated with the risk for noncontact knee injury. Promoting task complexity during rehabilitation and injury-prevention programs may better prepare individuals to succeed when performing high-risk athletic maneuvers.