5-Year Survival of Pediatric Anterior Cruciate Ligament Reconstruction With Living Donor Hamstring Tendon Grafts

Classifiers of anterior cruciate ligament status in female and male adolescents using return-to-activity criteria

PURPOSE

A lack of standardization exists for functional tasks in return-to-activity (RTA) guidelines for adolescents with anterior cruciate ligament injury (ACLi). Identifying the variables that discern ACLi status among adolescents is a first step in the creation of such guidelines following surgical reconstruction. This study investigated the use of classification models to discern ACLi status of adolescents with and without injury using spatiotemporal variables from functional tasks typically used in RTA guidelines for adults.

METHODS

Sixty-four adolescents with ACLi and 70 uninjured adolescents completed single-limb hops, lunges, squats, countermovement jumps and drop-vertical jumps. Jumping distances, heights, and depths were collected. Decision trees (DTs) were used to classify ACLi status and were evaluated using the F-measure (F1), kappa statistic (ĸ) and area under the precision-recall curve (PRC). Independent t tests and effect sizes were calculated for each important classifier of the DT models.

RESULTS

A five-variable model classified ACLi status with an accuracy of 67.5% (F1 = 0.6842; ĸ = 0.350; PRC = 0.491) with sex as a classifier. Significant differences were found in three of the four spatiotemporal variables (p ≤ 0.002). Separate models then classified ACLi status in males and females with an accuracy of 53.3% (F1 = 0.5882; ĸ = 0.0541; PRC = 0.476) and 76.9% (F1 = 0.7692; ĸ = 0.541; PRC = 0.528), respectively, with significant differences for all variables (p ≤ 0.013).

CONCLUSIONS

Among the DT models, females were better able to classify ACLi status compared to males, highlighting the importance of sex-specific rehabilitation guidelines for adolescents.

LEVEL OF EVIDENCE

Level III.

Sex Specific Considerations in Anterior Cruciate Ligament (ACL) Injuries in the Female Athlete: State of the Art

The increased participation of females in sports has been accompanied by an increase in the rate of anterior cruciate ligament (ACL) injuries. The literature has identified risk factors for non-contact ACL injuries in female athletes including anatomic, hormonal, biomechanical, neuromuscular, and environmental factors. This review will provide an overview of sex-specific considerations when managing female athletes with ACL injuries. A discussion of sex-specific surgical and rehabilitative treatment strategies with the goal of optimizing return to sport after ACL reconstruction will be emphasized.

Revision Anterior Cruciate Ligament Reconstruction in Pediatric and Adolescent Patients Yields Low Rates of Graft Failure and Good Functional Scores, but Low Rates of Return to Sport: A Systematic Review

PURPOSE

To evaluate outcomes after revision anterior cruciate ligament reconstruction (ACLR) in pediatric and adolescent patients in terms of graft failure rate and functional patient outcomes.

METHODS

A systematic review of Cochrane, Embase, Scopus, Ovid, and PubMed databases was performed for all original clinical studies that reported outcomes of pediatric and adolescent patients undergoing revision ACLR. Non-English studies and studies not reporting both graft failure rates and an additional outcome measure were excluded. We evaluated patient demographics, injury mechanisms, surgical technique characteristics, concomitant injuries, failure rates, patient-reported outcome measures (PROMs), complications, and return to sports rates. Risk of bias (ROB) was assessed with the methodological index for nonrandomized studies (MINORS).

RESULTS

Five studies with a total of 239 knees in 234 patients were included. Failure of the revision ACLR ranged from 9% to 21%. Return to previous level of activity ranged between 27% and 68%. PROMs were variable, with good Lysholm Knee Scoring Scale score (range 84.5-93.7), moderate Tegner Activity Score (range 5.5-9.0), and good International Knee Documentation Committee knee scores (range 79.9-80.0). Allograft was used in 48% of revisions, followed by bone patellar tendon bone autograft in 34%, and hamstrings (HS) autograft in 14%. Meniscus injury and cartilage injury was present in 53.1% to 92.5% and 5.5% to 59.4% of knees, respectively. Gwet's AC1 coefficient was 0.89, indicating a high degree of interrater reliability. The average MINORS score was 6, and heterogeneity was low (I2 = 9%). The included studies did not present with sufficient detail to disaggregate clinical outcomes by patient sex.

CONCLUSIONS

Revision ACLR yields a graft failure ranging from 9 to 20%. Revision patients experience good PROMs but low rates of return to preinjury level of sport. Further, revision ACLR was associated with high rates of intra-articular damage and relatively low rates of meniscal repair at the time of second surgery.

LEVEL OF EVIDENCE

Level IV, systematic review of level IV evidence.

Transphyseal arthroscopic anterior cruciate ligament reconstruction in children under 12 years

BACKGROUND

The incidence of anterior cruciate ligament (ACL) injuries in children is on the rise. Despite this trend, the optimal management of these injuries remains a matter of ongoing debate. In this light, our study seeks to assess the clinical, radiological, and functional outcomes of transphyseal ACL reconstruction in preadolescent patients in the medium-term.

METHODS

This prospective study included preadolescent patients aged up to 12 years who underwent ACL transphyseal reconstruction between 2010 and 2020 and had a minimum follow-up of 2 years. Clinical assessments encompassed joint stability and range of motion. Furthermore, leg length discrepancy (LLD) and femorotibial alignment were evaluated both clinically and radiologically using full-length lower limb standing radiographs. Pre- and postoperative functional outcomes were assessed using the International Knee Documentation Committee (IKDC) and Lysholm scales, and the return to normal sports activity was evaluated using the ACL-Return to Sport after Injury (ACL-RSI) scale. Complications and relevant follow-up data were also recorded. Statistical analyses were conducted to evaluate these outcomes.

RESULTS

A total of 35 preadolescent patients, consisting of 24 males and 11 females, with a mean age at surgery of 11.2 ± 0.7 years (8.7-12), were included in the study. The mean follow-up was 52.3 ± 20.7 months (24.1-95.9). No significant growth disturbances or clinically relevant LLD were evidenced. All patients demonstrated clinically stable knees with full range of motion at the 2-year follow-up. There were statistically significant improvements in pre- and postoperative IKDC (39.3 ± 13.5 vs. 99.7 ± 0.8, p < 0.005) and Lysholm scores (48.2 ± 15.1 vs. 99.6 ± 1.4, p < 0.005). All but two patients were able to return to their pre-injury level of sports activity, with a mean ACL-RSI score of 93.5 ± 1.3. The analysis revealed an 8.6% rerupture rate and an 11.4% rate of contralateral ACL injuries, with 5-year survival rates of 92.3% and 88.8%, respectively. Subgroup analyses based on age, gender, surgical delay, or associated meniscal lesions did not reveal any significant differences in functional outcomes. Additionally, there was no discernible relationship between age or timing of ACL reconstruction and the risk of meniscal injuries.

CONCLUSIONS

Our study reinforces the value of ACL reconstruction in skeletally immature preadolescent patients, with transphyseal technique proven to be a safe, effective, and technically simpler option, even for children under the age of 12. The findings indicate excellent functional outcomes, a high rate of successful return to sporting activities, and minimal to no incidence of growth-related complications in the medium-term.

LEVEL OF EVIDENCE

Level II, prospective comparative cohort study, before and after intervention.

Impact of Surgical Timing on Functional Outcomes after Anterior Cruciate Ligament Reconstruction

Objectives: Although acute anterior cruciate ligament reconstruction (ACLR) is often avoided because of postoperative joint stiffness, delayed ACLR can lead to a longer recovery time and can have a negative impact on physical function due to detraining. This study aimed to determine the effects of acute ACLR on postoperative outcomes, including muscle strength, performance, and return to sports. Methods: A total of 110 patients who underwent anatomical ACLR using hamstring autografts were included in this study and were divided into three groups: acute (ACLR performed within 2 weeks after ACL injury), 2-6 weeks (ACLR performed between 2 and 6 weeks after injury), and 6-12 weeks (ACLR performed between 6 and 12 weeks after injury). Several parameters were evaluated, including range of motion, knee joint stability, isokinetic knee strength, performance, and return to sports. Results: No significant differences were found in the range of motion or knee joint stability between the groups. The acute group exhibited significantly greater quadriceps strength at 3 months postoperatively than the other groups (p < 0.05). The single-leg hop test showed that 66.7%, 38.7%, and 33.3% of the patients in the acute, 2-6 weeks, and 6-12 weeks groups, respectively, recovered to an LSI of 90% or greater (p = 0.09, Cramer's V = 0.27). All patients in the acute group were able to return to sports (p = 0.14; Cramer's V = 0.28). Conclusions: Acute ACLR is advantageous for the early recovery of strength and performance without adverse events. Acute ACLR may shorten the time spent away from sports activities.

Risk Factors for Ipsilateral Versus Contralateral Reinjury After ACL Reconstruction in Athletes: A Systematic Review and Meta-analysis

Background

Anterior cruciate ligament (ACL) reinjury after ACL reconstruction (ACLR) can occur on the ipsilateral or contralateral side. Limited evidence exists regarding the difference between the incidence of reinjury to either knee, which is important in developing interventions to prevent ACL reinjury.

Purpose

To compare the reinjury rate of the ACL on the ipsilateral side versus the contralateral side in athletes after ACLR and investigate the risk factors that may cause different reinjury rates between the sides.

Study Design

Systematic review; Level of evidence, 4.

Methods

A systematic review was performed based on the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines. Studies that involved ACL reinjury in athletes after ACLR were reviewed. Considering several risk factors, including age and sex, a comparison of ACL reinjury incidence on the ipsilateral and contralateral sides was performed using a meta-analysis.

Results

Of the 17 selected studies, 3 were found to be at high risk of bias, and thus, 14 (n = 3424 participants) studies were included in the meta-analysis. In this athletic population, the contralateral ACL had a significantly higher rupture rate than the ipsilateral graft (risk ratio [RR], 1.41; P < .0001). Female athletes were found to have a greater risk of ACL reinjury on the contralateral versus the ipsilateral side (RR, 1.65; P = .0005), but different results were found in male athletes. (RR, 0.81; P = .21). There was no statistical difference in the incidence rate of ACL reinjury to either side in adolescent athletes (RR, 1.15; P = .28).

Conclusion

The contralateral ACL was more vulnerable to reinjury than the ipsilateral side in athletes after ACLR. Female athletes were more likely to reinjure their contralateral native ACL, while the same trend was not found in their male counterparts. The reinjury rate was comparable in both knees in adolescent athletes.

Reconsideration of Return-to-Sport Decision-Making After Pediatric ACL Injury: A Scoping Review

CONTEXT

Up to 90% of pediatric athletes return to sport (RTS) after anterior cruciate ligament reconstruction (ACL-R); however, <50% RTS at the same level and second ACL injury rates are up to 32%.

OBJECTIVES

(1) Determine which physical and patient-reported outcome measures guide clinical decision-making on RTS in pediatric athletes after ACL-R and (2) present a framework with insights from cognitive and neurophysiological domains to enhance rehabilitation outcomes.

DATA SOURCES

PubMed, CINAHL, Embrase, and Cochrane library databases and gray literature.

STUDY SELECTION

Data on pediatric (<18 years) ACL-R patients, RTS, tests, and decision-making were reported in 1214 studies. Two authors independently reviewed titles and abstract, excluding 962 studies. Gray literature and cross-reference checking resulted in 7 extra studies for full-text screening of 259 studies. Final data extraction was from 63 eligible studies.

STUDY DESIGN

Scoping review.

LEVEL OF EVIDENCE

Level 4.

DATA EXTRACTION

Details on study population, aims, methodology, intervention, outcome measures, and important results were collected in a data chart.

RESULTS

Studies included 4456 patients (mean age, 14 years). Quadriceps and hamstring strength (n = 25), knee ligament arthrometer (n = 24), and hop tests (n = 22) were the most-reported physical outcome measures guiding RTS in <30% of studies with cutoff scores of limb symmetry index (LSI) ≥85% or arthrometer difference <3 mm. There were 19 different patient-reported outcome measures, most often reporting the International Knee Documentation Committee (IKDC) (n = 24), Lysholm (n = 23), and Tegner (n = 15) scales. Only for the IKDC was a cutoff value of 85% reported.

CONCLUSION

RTS clearance in pediatric ACL-R patients is not based on clear criteria. If RTS tests were performed, outcomes did not influence time of RTS. Postoperative LSI thresholds likely overestimate knee function since biomechanics are impaired despite achieving RTS criteria. RTS should be considered a continuum, and biomechanical parameters and contextual rehab should be pursued with attention to the individual, task, and environment. There is a need for psychological monitoring of the ACL-R pediatric population.

Growth Disturbances Following Paediatric Anterior Cruciate Ligament Reconstruction: A Systematic Review

Growth disturbances after transphyseal paediatric anterior cruciate ligament (ACL) reconstruction have led to the development of physeal-sparing techniques. The aim of this study is to investigate growth disturbances following paediatric ACL reconstruction and identify associated risk factors. A systematic search on PubMed, Scopus and Web of Science databases was conducted using Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines to identify case series reporting paediatric ACL reconstructions. Of 518 articles, 78 met the inclusion criteria, and data related to growth disturbances and graft failures were extracted. A total of 2,693 paediatric ACL reconstructions resulted in 70 growth disturbances (2.6%): 17 were varus, 26 were valgus, 13 were shortening, 14 were lengthening and five patients had reduced tibial slope. Some patients showed deformities in more than one plane. Coronal plane deformities were seen more frequently with eccentric physeal arrest and lengthening with intraepiphyseal tunnelling. Shortening and reduced tibial slope were related to large central physeal arrest and anterior tibial physeal arrest, respectively. Sixty-two studies documented 166 graft failures in 2,120 reconstructions (7.8%). The extraphyseal technique was least likely to result in growth disturbances and graft failure. Paediatric ACL reconstruction is a safe and effective treatment of rupture. Growth disturbances are least likely following extraphyseal tunnelling, and those resulting from transphyseal techniques can be minimised by reducing drill size, drilling steep and avoiding the physeal periphery. The insertion of hardware, synthetic material, or a bone plug through the drilled physis should be avoided. There is a greater need for robust long-term data collection, such as national ligament registries, to standardise practice and evaluate the risk of growth disturbance and re-ruptures in this treatment.

Physeal-sparing ACL reconstruction provides better knee laxity restoration but similar clinical outcomes to partial transphyseal and complete transphyseal approaches in the pediatric population: a systematic review and meta-analysis

PURPOSE

The aim of this meta-analysis was to evaluate complete transphyseal (CTP), partial transphyseal (PTP), and physeal-sparing (PS) techniques for anterior cruciate ligament (ACL) reconstruction.

METHODS

A systematic literature search of the PubMed, Web of Science, Cochrane Library, and Scopus literature databases was performed on 10.05.2021. All human studies evaluating the outcomes of CTP, PTP, and PS techniques were included. The influence of the selected approach was evaluated in terms of rates of retears, return to previous level of sport competition, IKDC subjective and objective scores, Lysholm score, rate of normal Lachman and pivot-shift tests, limb length discrepancy, and hip-knee angle (HKA) deviation. Risk of bias and quality of evidence were assessed following the Downs and Black checklist.

RESULTS

Forty-nine out of 425 retrieved studies (3260 patients) met the inclusion criteria. The results of the meta-analysis comparing CTP, PTP, and PS approaches for ACL reconstruction in the under 20-year-old population showed a significant difference in terms of differential laxity (CTP 1.98 mm, PTP 1.69 mm, PS 0.22 mm, p < 0.001). No significant differences were seen in terms of growth malalignment, rate of normal Lachman and pivot-shift tests, and rate of normal/quasi-normal IKDC objective score.

CONCLUSIONS

The present meta-analysis found overall similar results with the three ACL reconstruction approaches. The PS technique showed better results in terms of knee laxity than the PTP and CTP approaches, but this did not lead to a significant difference in terms of subjective and objective scores. No clear superiority of one technique over the others was found with respect to re-ruptures, growth disturbances, and axial deviations. While the argument for avoiding growth malalignment does not seem to be a crucial point, the PS technique should be the preferred approach in a young population to ensure knee laxity restoration.

LEVEL OF EVIDENCE

Level III.

Return to Sports: A Risky Business? A Systematic Review with Meta-Analysis of Risk Factors for Graft Rupture Following ACL Reconstruction

BACKGROUND

The risk of sustaining a graft rupture after anterior cruciate ligament reconstruction (ACLR) is high. Contributing risk factors are, however, still not clearly identified.

OBJECTIVE

The aim of this systematic review was to identify and quantify risk factors for graft rupture after ACLR.

METHODS

A systematic review with meta-analysis (PROSPERO CRD42020140129) based on PRISMA guidelines was performed. MEDLINE, CINAHL and EMBASE were searched from inception to September 2021. Prospective and retrospective studies addressing risk factors for graft rupture after ACLR in males/females of all ages were considered. Meta-analyses using a random effect model (effect measure: odds ratio [OR] with 95% confidence interval [CI]) were performed. The GRADE tool was used to assess evidence quality.

RESULTS

Following full-text screening of 310 relevant papers, 117 were eventually included, incorporating up to 133,000 individuals in each meta-analysis. Higher Tegner activity level (≥ 7 vs < 7) at primary injury (OR 3.91, 95% CI 1.69-9.04), increased tibial slope (degrees) (OR 2.21, 95% CI 1.26-3.86), lower psychological readiness to return to sport (RTS) (OR 2.18, 95% CI 1.32-3.61), early surgery (< 12 vs ≥ 12 months) (OR 1.87, 95% CI 1.58-2.22), RTS (pre-injury level) (OR 1.87, 95% CI 1.21-2.91) and family history of ACL injury (OR 1.76, 95% CI 1.34-2.31) were all associated with increased odds of graft rupture. Higher age (OR 0.47, 95% CI 0.39-0.59), female sex (OR 0.88, 95% CI 0.79-0.98), fewer self-reported knee symptoms pre-reconstruction (OR 0.81, 95% CI 0.69-0.95) and concomitant cartilage injuries (OR 0.70, 95% CI 0.62-0.79) instead decreased the odds. Meta-analysis revealed no association between body mass index, smoking, joint laxity, RTS time, knee kinematics, muscle strength or hop performance and graft rupture.

CONCLUSION

Conspicuous risk factors for graft rupture were mainly sports and hereditary related. Few studies investigated function-related modifiable factors or included sports exposure data.

Risk of reoperation after primary anterior cruciate ligament reconstruction in children and adolescents

OBJECTIVE

To examine the incidence and risk factors of any-cause reoperation after primary ACLR in children and adolescents.

DESIGN

Retrospective Cohort.

SETTING

Electronic medical records from a large tertiary care, single institution integrated healthcare delivery system.

PATIENTS

Patients were under the age of 18 years and had anterior cruciate ligament reconstruction. They were excluded if they had a multi-ligamentous knee injury or <1 year follow-up.

INTERVENTIONS

Patients were further identified to have undergone a subsequent knee operation ipsilaterally or contralateral ACLR.

MAIN OUTCOME MEASURES

The rate of any-cause reoperation was our primary outcome measure.

RESULTS

The median age was 16. There were 208 females (53.9%) and 178 males (46.1%) included. The median follow-up was 25 months with a minimum of 12 months (interquartile range: 16.0, 46.0). The rate of any-cause reoperation was 34.7%. There was no statistically significant difference between those who underwent reoperation versus those who did not undergo reoperation relative to age, sex, BMI, graft type, or the presence of concomitant meniscal injury. The rates of ipsilateral ACLR and contralateral ACLR at any time during the study period was 8.0% and 10.9% respectively. There was no statistically significant difference for rate of reoperation between graft types, between various concomitant injuries, between those who underwent meniscus repair or no repair.

CONCLUSIONS

This study reflects a 34.7% rate of a subsequent knee operation after ACLR in patients younger than 18 years. These findings can be used to inform pediatric patients undergoing primary ACLR on their risk of returning to the operating room.

Anterior Cruciate Ligament Rupture in Skeletally Immature Patients

In the past 20 years, sports injuries in pediatric and adolescent athletes have increased dramatically, with anterior cruciate ligament (ACL) injuries accounting for more than 25% of all knee injuries at this age. Diagnosis is based on detailed clinical history, physical examination, and imaging assessment, where magnetic resonance imaging plays a central role. The growing immature skeleton presents specific characteristics, which require unique methods for surgical reconstruction, ideally avoiding the physes or minimizing the risk of damaging them. Specific rehabilitation protocols are needed, and these patients face a higher risk of recurrent and contralateral ACL injury. Nonsurgical treatment or delayed reconstruction has been associated with persistent instability, activity modifications, worst functional outcomes, and increased risk of irreparable injuries to menisci and articular cartilage. Consequently, surgical stabilization is the preferred treatment for most patients, despite the eventual risk of angular deformities or limb-length discrepancies due to iatrogenic physeal injury. A variety of surgical techniques have been described, depending on the skeletal maturity and growth remaining. Targeted prevention programs play a key role in reducing the risk of ACL injury, are easy to implement, and require no additional equipment. High-quality evidence supports its use in all pediatric athletes.

Suture Tape Augmentation Improves the Biomechanical Performance of Bone-Patellar Tendon-Bone Grafts Used for Anterior Cruciate Ligament Reconstruction

PURPOSE

The purpose of this study was to investigate the time-zero biomechanical properties (stiffness, displacement, and load at failure) of bone-patellar tendon-bone (BTB) grafts used for anterior cruciate ligament (ACL) reconstruction with and without suture tape augmentation as a means to determine the potential clinical benefit of this technique.

METHODS

Eight juvenile porcine knees underwent ACL reconstruction with a human cadaveric BTB graft (control). These were compared to 8 juvenile porcine knees that underwent ACL reconstruction with a BTB graft augmented with suture tape. All knees underwent biomechanical testing utilizing a dynamic tensile testing machine. Cyclic loading between 50-250N was performed for 500 cycles at 1 Hz to simulate in vivo ACL loads during the early rehabilitation phase. The grafts were displaced during load-at-failure tensile testing at 20 mm/min. Differences in graft displacement, stiffness, and load at failure for the control and suture tape augmented groups were compared with the Student t-test with a significance level of P < .05.

RESULTS

There was no difference in graft displacement between the 2 groups. A 104% higher postcyclic stiffness was noted in the augmented group compared to the controls (augmentation: 261 ± 76 N/mm versus control 128 ± 28 N/mm, P = .002). The mean ultimate load at failure was 57% higher in the augmented group compared to controls (744 ± 219 N vs postcyclic 473 ± 169 N, respectively [P = .015]). There was no difference in mode of failure between the control knees and those augmented with suture tape, with approximately half failing from pull off of the tendon from the bone plug and half with pull out of the bone plug from the tunnel.

CONCLUSION

Independent suture tape augmentation of a BTB ACL reconstruction grafts was associated with a 104% increase in graft stiffness and a 57% increase in load at failure compared to nonaugmented BTB grafts.

CLINICAL RELEVANCE

In vivo suture tape augmentation of a BTB ACL reconstruction increases graft construct strength and stiffness, which may reduce graft failure in the clinical setting.

Does sex affect second ACL injury risk? A systematic review with meta-analysis

OBJECTIVE

To determine sex-based differences in risk of a second ACL injury (overall and by laterality) following primary ACL reconstruction in athletes who are attempting to return to sport.

DESIGN

Systematic review with meta-analysis.

DATA SOURCES

Systematic search of five databases conducted in August 2019.

ELIGIBILITY CRITERIA FOR SELECTING STUDIES

Studies reporting sex-based differences in the incidence of second ACL injury in athletes attempting to return-to-sports and who were followed for at least 1 year following primary ACL reconstruction.

RESULTS

Nineteen studies were included in this review, with seven studies excluded from the primary meta-analysis due to high risk of bias. The remaining 12 studies (n=1431 females, n=1513 males) underwent meta-analysis, with all 19 studies included in a sensitivity analysis. Total second ACL injury risk was 21.9% (females: 22.8%, males: 20.3%). Females were found to have 10.7% risk of an ipsilateral ACL injury and 11.8% risk of a contralateral ACL injury. Males were found to have 12.0% risk of an ipsilateral ACL injury and 8.7% risk of a contralateral ACL injury. No statistically significant differences were observed for total second ACL injury risk (risk difference=-0.6%, 95% CI -4.9 to 3.7, p=0.783, I²=41%) or contralateral ACL injury risk (risk difference=1.9%, 95% CI -0.5% to 4.4%, p=0.113, I²=15%) between sexes. Females were found to have a 3.4% absolute risk reduction in subsequent ipsilateral ACL injury risk compared with males (risk difference=-3.4%, 95% CI -6.7% to -0.02%, p=0.037, I²=35%).

CONCLUSION

Both sexes have >20% increased risk of experiencing a second ACL injury. Any difference in the absolute risk of either a subsequent ipsilateral or contralateral ACL injury between sexes appears to be small.

REGISTRATION

PROSPERO (CRD42020148369).

Risk Factors for Contra-Lateral Secondary Anterior Cruciate Ligament Injury: A Systematic Review with Meta-Analysis

Background

The risk of sustaining a contra-lateral anterior cruciate ligament (C-ACL) injury after primary unilateral ACL injury is high. C-ACL injury often contributes to a further decline in function and quality of life, including failure to return to sport. There is, however, very limited knowledge about which risk factors that contribute to C-ACL injury.

Objective

To systematically review instrinsic risk factors for sustaining a C-ACL injury.

Methods

A systematic review with meta-analysis was performed according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Four databases (MEDLINE, CINAHL, EMBASE, Sport Discus) were searched from inception to January 2020. Inclusion criteria were prospective or retrospective studies investigating any intrinsic risk factor for future C-ACL injury. Meta-analysis was performed and expressed as odds ratios (OR) if two or more articles assessed the same risk factor.

Results

44 moderate-to-high quality studies were eventually included in this review, whereof 35 studies were eligible for meta-analysis, including up to 59 000 individuals. We identified seven factors independently increasing the odds of sustaining a C-ACL injury (in order of highest to lowest OR): (1) returning to a high activity level (OR 3.26, 95% CI 2.10–5.06); (2) Body Mass Index < 25 (OR 2.73, 95% CI 1.73–4.36); (3) age ≤ 18 years (OR 2.42, 95% CI 1.51–3.88); (4) family history of ACL injury (OR 2.07, 95% CI 1.54–2.80); (5) primary ACL reconstruction performed ≤ 3 months post injury (OR 1.65, 95% CI: 1.32–2.06); (6) female sex (OR 1.35, 95% CI 1.14–1.61); and (7) concomitant meniscal injury (OR 1.21, 95% CI 1.03–1.42). The following two factors were associated with decreased odds of a subsequent C-ACL injury: 1) decreased intercondylar notch width/width of the distal femur ratio (OR 0.43, 95% CI 0.25–0.69) and 2) concomitant cartilage injury (OR 0.83, 95% CI 0.69–1.00). There were no associations between the odds of sustaining a C-ACL injury and smoking status, pre-injury activity level, playing soccer compared to other sports or timing of return to sport. No studies of neuromuscular function in relation to risk of C-ACL injury were eligible for meta-analysis according to our criteria.

Conclusion

This review provides evidence that demographic factors such as female sex, young age (≤ 18 years) and family history of ACL injury, as well as early reconstruction and returning to a high activity level increase the risk of C-ACL injury. Given the lack of studies related to neuromuscular factors that may be modifiable by training, future studies are warranted that investigate the possible role of factors such as dynamic knee stability and alignment, muscle activation and/or strength and proprioception as well as sport-specific training prior to return-to-sport for C-ACL injuries.

PROSPERO: CRD42020140129.

Supplementary Information

The online version contains supplementary material available at 10.1007/s40279-020-01424-3.

Transphyseal anterior cruciate ligament reconstruction using living parental donor hamstring graft: excellent clinical results at 2 years in a cohort of 100 patients

PURPOSE

To determine outcomes of transphyseal ACL reconstruction using a living parental hamstring tendon allograft in a consecutive series of 100 children.

METHODS

One hundred consecutive juveniles undergoing ACL reconstruction with a living parental hamstring allograft were recruited prospectively and reviewed 2 years after ACL reconstruction with IKDC Knee Ligament Evaluation, and KT1000 instrumented laxity testing. Skeletally immature participants obtained annual radiographs until skeletal maturity, and long leg alignment radiographs at 2 years. Radiographic Posterior tibial slope was recorded.

RESULTS

Of 100 juveniles, the median age was 14 years (range 8-16) and 68% male. At surgery, 30 juveniles were graded Tanner 1 or 2, 21 were Tanner 3 and 49 were Tanner 4 or 5. There were no cases of iatrogenic physeal injury or leg length discrepancy on long leg radiographs at 2 years, despite a median increase in height of 8 cm. Twelve patients had an ACL graft rupture and 9 had a contralateral ACL injury. Of those without further ACL injury, 82% returned to competitive sports, IKDC ligament evaluation was normal in 52% and nearly normal in 48%. The median side to side difference on manual maximum testing with the KT1000 was 2 mm (range - 1 to 5). A radiographic PTS of 12° or more was observed in 49%.

CONCLUSIONS

ACL reconstruction in the juvenile with living parental hamstring tendon allograft is a viable procedure associated with excellent clinical stability, patient-reported outcomes and return to sport over 2 years. Further ACL injury to the reconstructed and the contralateral knee remains a significant risk, with identical prevalence observed between the reconstructed and contralateral ACL between 12 and 24 months after surgery.

LEVEL OF EVIDENCE

III (Cohort Study).

Postural stability and regulation before and after anterior cruciate ligament reconstruction - A two years longitudinal study

OBJECTIVES

To evaluate postural regulation and stability among patients who underwent anterior cruciate ligament reconstruction (ACLR) and rehabilitation over a two-year follow-up period.

DESIGN

Longitudinal; SETTING: Biomechanics laboratory; PARTICIPANTS: 30 ACLR patients (32.0 ± 12.2 years, 14 males) with isolated ACL rupture.

MAIN OUTCOME MEASURES

Postural regulation was tested before ACLR, as well as at six-weeks, twelve-weeks, six-months, one-year and two-years post-ACLR and standardized rehabilitation. Postural regulation was measured for stability indicator (ST), weight distribution index (WDI), synchronization (foot coordination) and sway intensities (postural subsystems).

RESULTS

Significant time effects (pre-vs. two-years postoperative) were found for WDI (η_p² = 0.466), synchronization (η_p² = 0.368), mediolateral weight distribution (η_p² = 0.349), ST (η_p² = 0.205), visual/nigrostriatal systems (η_p² = 0.179) and peripheral-vestibular system (η_p² = 0.102). The largest difference (preoperative: η_p² = 0.180) to the matched sample was calculated for WDI. The most significant differences to the matched sample were observed for ST (preoperative: η_p² = 0.126; six-weeks postoperative: η_p² = 0.103) and WDI (preoperative: η_p² = 0.180; six-weeks postoperative: η_p² = 0.174).

CONCLUSION

ACLR and rehabilitation influence postural subsystems, postural stability, weight distribution and foot synchronization. Normalization of mediolateral weight distribution requires one year following ACLR. The ACLR leads to a suppression of the somatosensory and cerebellar system which was compensated by a higher activity of the visual and nigrostriatal systems.