Outcome Measures After ACL Injury in Pediatric Patients: A Scoping Review

Abstract

Background:

The incidence of anterior cruciate ligament (ACL) injuries in children is increasing. However, no standardized core set of outcome measures exists for evaluating pediatric ACL injuries.

Purpose:

To perform a scoping review of the literature to identify patient-reported outcome measures (PROMs) and objective outcome measures used to evaluate pediatric patients after ACL injury and to classify these in accordance with the International Classification of Functioning, Disability, and Health (ICF) domains.

Study Design:

Systematic review; Level of evidence, 4.

Methods:

The literature was systematically searched with the PubMed, EMBASE, CINAHL, and PEDro databases. The inclusion criteria were Danish, Norwegian, Swedish, German, or English language; publication between 2010 and 2018; pediatric ACL injury (patients ≤15 years old); and outcome measures. The selected papers were screened for title, abstract, and full text in accordance with predefined inclusion and exclusion criteria.

Results:

A total of 68 papers (4286 patients; mean ± SD age, 12.2 ± 2.3 years) were included. Nineteen PROMs and 11 objective outcome measures were identified. The most frequently reported PROMs were the International Knee Documentation Committee (IKDC) Subjective Knee Form (51% of studies), Lysholm scoring scale (46% of studies) and Tegner activity rating scale (37% of studies). Additionally, return to sport was reported in 41% of studies. The most frequent objective measures were knee laxity (76% of studies), growth disturbances (69% of studies), range of motion (41% of studies), and muscle strength (21% of studies). With respect to the ICF domains, the IKDC covered all 3 ICF health domains, the Lysholm score covered the Body Structure and Function and the Activity Limitation domains, while the Tegner score covered the Participation Restriction domain. Objectively measured knee joint laxity, range of motion, and muscle strength covered 1 domain (Body Structure and Function).

Conclusion:

Pediatric patients with ACL injury were mainly evaluated subjectively with the IKDC and objectively by knee joint laxity. No consensus exists in the evaluation of children after ACL injury. The majority of applied outcome measures are developed for adults. To cover the ICF health domains, future research needs to consider reliable and valid outcome measures relevant for pediatric patients with ACL injury.

Keywords

children anterior cruciate ligament clinical outcomes knee function rehabilitation sports medicine

The incidence of anterior cruciate ligament (ACL) injuries in children has been steadily increasing through the past 10 years.^82,96 Thus, pediatric ACL injuries have attracted substantial interest in clinical research, and the need for prospective research on outcomes after surgical and nonsurgical treatment has been highlighted.² However, to provide a scientific basis that can evaluate the consequences of pediatric ACL injuries, it is imperative to have relevant and valid outcome measures. A review of clinical research on adults with ACL injury found high variability in outcome reporting.⁵³ Furthermore, a 2017 review on reporting trends in youth ACL reconstructions found diverse definitions of skeletal maturity, inconsistently reported objective outcome measures, and the use of patient-reported outcome measures (PROMs) that were developed and validated for adults.¹⁰ Inconsistent and nonstandardized outcome reporting reduces the possibility of comparing and interpreting results across different studies. It is unknown if the high variability in outcome measures seen in adults and adolescents is present in the literature on pediatric ACL injuries.

It is well documented that an ACL injury can have a large impact on function and health in both a short- and long-term perspective.⁹⁷ Ideally, outcome assessment should cover every aspect of function and health in pediatric patients with ACL injury. The World Health Organization has formulated the International Classification of Functioning, Disability, and Health (ICF).¹⁰⁰ The ICF is a standardized framework of health and health-related domains (Body Structure and Function, Activity Limitation, and Participation Restriction) that are considered essential for the overall well-being and health of a person. Whether outcome measures used in pediatric patients with ACL injury cover the different ICF domains has yet to be evaluated. Thus, the purpose of this scoping review was to identify outcome measures reported in the literature on pediatric ACL injuries (patients ≤15 years of age) and to examine how the outcome measures were related to the different ICF domains.

Methods

This scoping review was designed according to the methodological framework presented by Arksey and O’Malley.³ This framework was further refined, and 5 stages were proposed to be followed when conducting a scoping review: (1) the identification of a research question; (2) finding the relevant studies; (3) the selection of studies to be included in the review; (4) data extraction from the included studies; and (5) assembling, summarizing, and reporting the results of the review.⁸

Identification of Research Questions

Two research questions were formulated: (1) Which outcome measures are reported in the literature on pediatric ACL injuries (≤15 years of age)? and (2) How do outcome measures reported in the literature on pediatric ACL injuries relate to the different ICF domains? The decision to study participants with an age ≤15 years was a pragmatic solution to focus on children and not adolescents or adults.

Identifying Relevant Studies

The literature was searched in the following databases: PubMed, EMBASE, CINAHL, and PEDro. The end search date for all databases was November 22, 2018. Two members of the research team (M.H.K., M.B.P.) carried out the literature search in the electronic databases. Inclusion criteria were studies (1) reporting results from clinical interventions or treatment of ACL injury including children with a median or mean age ≤15 years; (2) published in the period from 2010 to 2018; and (3) published in Danish, Norwegian, Swedish, German, or English. Exclusion criteria were (1) animal or anatomic studies, (2) reviews/meta-analyses, (3) patients with additional knee injuries (except for meniscal injury), and (4) patients with avulsion fractures. On the basis of the inclusion and exclusion criteria, we constructed a search matrix, which was as follows for PubMed searches: (ACL OR “anterior cruciate ligament” OR “Anterior Cruciate Ligament”[MeSH] OR “Anterior Cruciate Ligament Reconstruction”[MeSH]) AND (“Child”[MeSH] OR “Adolescent”[MeSH] OR “Pediatrics”[MeSH] OR preschool* OR pediatric* OR adolescent* OR child* OR prepubescent*). We customized this matrix for searches in the 3 other databases.

Study Identification

Two members of the research team (M.H.K., M.B.P.) screened all identified studies and removed all duplicates, all studies published earlier than 2010, and those that did not meet the language inclusion criteria. The remaining studies were then screened for eligibility by 5 members of the research team (M.H.K., M.B.P., M.K.Z., S.W., T.A.). Two persons screened the title and abstract of each study independently, and in case of disagreement a third person from the research team was consulted to determine the eligibility. Finally, the full-text of the remaining studies were reviewed for eligibility by 2 persons, and conflicts were resolved by asking a third person. In every case of conflict, it was possible to reach consensus through this procedure. M.H.K. or M.B.P. scrutinized the reference lists of all the included studies to identify studies that did not appear in the searches of the electronic databases. In case new studies were identified, these underwent the same screening procedure as described and were termed “additional records identified through other sources” (Figure 1).

Figure 1.

PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) flow diagram.

Data Extraction

Data extraction for each eligible study was performed independently by 3 reviewers (M.K.Z., T.A., S.W.) with a predefined spreadsheet. The reviewers’ spreadsheets were then merged to create an agreed-upon extraction form. The standardized data extraction form included details such as study focus, study design, evidence level, authors and country, participant details, and outcome measures (patient-reported and objective outcomes).

Data Analysis

All analyses were performed by 2 authors (M.B.P., M.K.Z.) and verified by 2 authors (S.W., T.A.). The analyses performed were assessment of the variability and frequency of outcome measures, division into patient-reported and objective outcome measures, outcome measures reported per study, research groups, level of evidence,⁷¹ and classification of outcome measures according to ICF domains.¹⁰⁰ Data are presented as numbers of studies, percentage of studies, and mean ± SD where relevant.

ICF Domains

Outcome measures were classified according to the following ICF domains¹⁰⁰:

(1) Body Structure and Function: Impairments in body structure are problems with the anatomic feature of the body, whereas impairments in body function are problems with the function of the body system.

(2) Activity Limitation: This domain refers to the difficulties that an individual may have in executing activities.

(3) Participation Restriction: This domain includes normal daily activities, such as working, engaging in social and recreational activities, and obtaining health care and preventive services.

The classification was carried out independently by 2 physical therapists of the research team (S.P.M., M.H.K.) and verified by a third physical therapist who was not a member of the research team.

Results

Included Studies

As Figure 1 demonstrates, 12,689 citations were identified through the search strategy. Sixty-eight papers fulfilled the inclusion criteria^＃ and were included in the review. In total, 4286 patients with a mean age of 12.2 ± 2.3 years were evaluated in the 68 studies included. In 60 studies, surgery/reconstruction was evaluated as treatment; in 3 studies, conservative treatment was evaluated; and in 5 studies, both treatments were evaluated.

In total, 22 scientific journals were represented among the included studies (Table 1). The most frequent journals were Knee Surgery, Sports Traumatology, Arthroscopy (14 studies), Journal of Pediatric Orthopaedics (9 studies), and The American Journal of Sports Medicine (9 studies). The review included 8 studies with an evidence level of 5, 50 level 4 studies, 9 level 3 studies, and 1 level 2 study. On average, 8 ± 3 outcome measures were reported per study, and 85% of the studies used a combination of objective and subjective outcome measures in the evaluation of knee function.

TABLE 1

Journals of the Included Studies

Journal	Articles, n
Knee Surgery, Sports Traumatology, Arthroscopy	14
Journal of Pediatric Orthopaedics	9
The American Journal of Sports Medicine	9
The Orthopaedic Journal of Sports Medicine	5
Orthopaedics & Traumatology, Surgery & Research	4
The Journal of Bone and Joint Surgery	4
The International Journal of Sports Physical Therapy	3
The Journal of Arthroscopic and Related Surgery	2
The Knee	2
Clinical Orthopaedics and Related Research	2
Journal of Orthopaedic Surgery	2
Arthroscopy Techniques	2
BMJ Case Reports	1
Orthopedics	1
The American Journal of Orthopaedics	1
Sports Health	1
Arthroscopy	1
Revista Brasileira de Ortopedia	1
Pediatric Physical Therapy	1
Sports Medicine, Arthroscopy, Rehabilitation, Therapy & Technology	1
British Journal of Sports Medicine	1
Acta Orthopaedica et Traumatologica Turcica	1

Patient-Reported Outcomes

In total, 19 PROMs were identified in this scoping review (Figure 2). The most frequently reported questionnaires were the International Knee Documentation Committee (IKDC) Subjective Knee Form³⁵ (51%), the Lysholm scoring scale⁹⁰ (46%), and the Tegner activity rating scale⁹ (37%), respectively. Knee pain, specifically evaluated as an isolated measure, was assessed and reported in 32% of the studies. The most frequently used outcome for knee pain was a simple yes/no question (9 of 68 studies), followed by visual analog scale score (4 of 68 studies) and numeric rating scale (2 of 68 studies). In 41% of the studies, return to sport was used as a follow-up outcome measure.

Figure 2.

Patient-reported outcome measures. ACL-RSI, ACL–Return to Sport After Injury Scale⁹⁵; EQ-5D, European Quality of Life–5 Dimensions⁸⁶; HSS Pedi-FABS, Hospital for Special Surgery Pediatric Functional Activity Brief Scale²²; IKDC, International Knee Documentation Committee³⁵; KOOS, Knee injury and Osteoarthritis Outcome Score⁷⁹; KOOS-Child, Knee injury and Osteoarthritis Outcome Score for Children⁷⁰; KOS-ADL, Knee Outcome Survey–Activities of Daily Living³⁶; MARS, Marx activity rating scale⁵⁵; OAK, The Orthopädische Arbeitsgruppe Knie Score⁶⁵; Pedi-IKDC, Pediatric International Knee Documentation Committee⁴¹; SANE, Single Assessment Numerical Evaluation⁸⁸; SF-36, 36-Item Short-Form Health Survey.⁹⁴

Three of the identified PROMs were specific measures for pediatric patients—that is, the Pedi-IKDC,⁴¹ Knee injury and Osteoarthritis Outcome Score for Children (KOOS-Child),⁷⁰ and the Hospital for Special Surgery Pediatric Functional Activity Brief Scale (HSS Pedi-FABS).²² These PROMs were used in 5,^{40,61,93,98,99} 1,⁸⁵ and 1¹⁶ of the 68 studies, respectively. Of the 5 studies including the Pedi-IKDC as an outcome measure, 1 was published in 2013,⁶¹ 1 in 2015,⁹⁸ 1 in 2017,⁹³ and 2 in 2018^40,99.

Objective Outcome Reporting

In 76% of the studies reviewed, knee laxity was a reported objective outcome. Knee laxity tests included instrumented assessment in 35 studies (51%), Lachman testing in 32 (47%), pivot-shift testing in 28 (41%), and anterior drawer testing in 6 studies (9%). Of the 35 studies reporting instrumented knee laxity outcomes, the majority used KT arthrometers (29 studies). Range of motion (ROM) was reported in 41% of the studies reviewed. Isokinetic muscle strength was reported in 14 studies (21%); quadriceps muscle strength was reported in all 14 studies and hamstring muscle strength in 11 of the 14 studies. The Limb Symmetry Index was reported in 8 of the 11 studies.

With respect to functional testing, 12 studies (18%) reported hop test outcomes. Of these, 10 studies reported the single-legged hop test for distance, and 6 studies reported the single-legged triple-hop test. Additionally, crossover and vertical hop tests were each reported in 4 studies. The Functional Movement Screen test,⁶⁰ which consists of 7 dynamic tests, was reported in 2 studies. The remaining objective outcomes were found in 1% of the studies reviewed (Figure 3).

Figure 3.

Objective outcome reporting. ROM, range of motion.

Adverse Events

In total, 59 studies reported adverse events as an outcome. In terms of follow-up outcome measures, 69% of the included studies reported growth disturbance, 40% reported reinjury, and 22% reported reoperation.

ICF Domains

The most frequently used outcome measures within the ICF Body Structure and Function domain were laxity testing, ROM, and muscle strength testing (Table 2). The IKDC³⁵ and the Pedi-IKDC⁴¹ address aspects of physical impairment but they also evaluate the domains Activity Limitation and Participation Restriction. The IKDC and Pedi-IKDC questionnaires provide information about symptoms, daily activity, and sports function owing to a variety of conditions affecting the knee, including ligament injuries. Additional outcome measures that can be allocated to the ICF domain Body Function and Structure include the Lysholm scoring scale,⁹⁰ which assesses knee function after knee ligament injury. The scale consists of 8 items: pain, instability, locking, swelling, limp, stair climbing, squatting, and need for support. The Lysholm test also covers the domain Activity Limitation. Functional testing (eg, hop testing) covers the domain Activity Limitation. Information linked to the ICF domain Participation Restriction includes the Tegner activity rating scale.⁹

TABLE 2

ICF Domain Classification for Commonly Used Outcome Measures in Pediatric ACL Injury Rehabilitation ^a

		ICF Domain
Outcome Measure	Articles, n ^b	Body Structure and Function	Activity Limitation	Participation Restriction
Laxity testing	52	×
Instrumented	35	× (b7150)
Lachman test	32	× (b7150)
Pivot shift	28	× (b7100)
Anterior drawer	6	× (b7150)
Range of motion	28	× (b7100)
Functional testing	12		×
Hop test	12		× (d4553)
Adverse events
Growth disturbance	47
Reinjury	27
Reoperation	15
Isokinetic muscle strength	14	× (b7300)
Quadriceps	14	×
Hamstring	11	×
LSI	8	×
PROMs
IKDC	35	×	×	×
Lysholm	31	×	×
Tegner	25			×
Pain score	22	×
Pedi-IKDC	5	×	×	×

^a Parentheses represent ICF codes.¹⁰⁰ ACL, anterior cruciate ligament; ICF, International Classification of Functioning, Disability, and Health; IKDC, International Knee Documentation Committee; LSI, Limb Symmetry Index; PROM, patient-reported outcome measure.

^b Out of 68 total.

Discussion

The aim of this study was to provide an overview of outcome measures utilized after pediatric ACL injury and to examine how these relate to the 3 domains of the ICF. We included 68 studies published in a variety of international peer-reviewed journals, including journals that address orthopaedic surgeons, team physicians, athletic trainers, and physical therapists specializing in sports medicine (eg, The American Journal of Sports Medicine) and journals mainly addressing specialist orthopaedic surgeons (eg, The Journal of Bone and Joint Surgery).

The level of evidence in most of the included studies (58 of 68) was low. We identified 1 level 2 study and no studies of level 1. This concurs with previous observations.^10,62 In contrast, Makhni et al⁵³ found that 50% of the included studies in a review of the adult ACL reconstruction literature were level 1 or 2 studies.

We did not find any standardized outcome measure for pediatric patients with ACL injury consistently utilized across the included studies. The majority of the outcome measures were identical to those used among the adult population with ACL injury,⁵³ which have not been developed and validated for pediatric patients undergoing treatment and rehabilitation after ACL injury.

It is important to stress that we decided to include ACL injury studies with patients of a median or mean age of maximum 15 years. As such, some of these patients may have been skeletally mature. However, the mean age of the 4286 patients was 12.2 ± 2.3 years—thus, it is likely that the majority of the patients were skeletally immature.

This scoping review found the IKDC to be the most commonly used PROM, appearing in 51% of studies, followed by the Lysholm score (46%) and the Tegner score (37%), which demonstrates that the most commonly reported PROMs are not specifically developed for pediatric patients with ACL injury. A similar reporting pattern was found in a review of youth ACL reconstruction studies.¹⁰

Overall, the present review identified only 3 PROMs that were specifically developed for pediatric patients with knee disorders in general—the Pedi-IKDC, KOOS-Child, and HSS Pedi-FABS. The Pedi-IKDC and KOOS-Child questionnaires are adapted from their adult versions, which are PROMs designed to assess self-reported knee function. The Pedi-IKDC has demonstrated overall acceptable psychometric performance for outcome assessment of children and adolescents from 10 to 18 years of age with various disorders of the knee.⁴¹ Likewise, the KOOS-Child has demonstrated good psychometric properties in 7- to 16-year-old children with knee disorders.⁶⁹ In a consensus statement by Ardern et al,² the Pedi-IKDC and KOOS-Child were suggested as appropriate PROMs for children with ACL injury. In our review, only 5 studies used the Pedi-IKDC, and 1 study used the KOOS-Child. This finding is in accordance with the review by Brusalis et al¹⁰ on youth ACL reconstruction studies, who found that the Pedi-IKDC was reported in only 1 of the 17 included studies. The 8-item HSS Pedi-FABS is a reliable and valid metric to assess activity in children and adolescents 10 to 18 years of age.²² This PROM was reported in only 1 of the included studies. Thus, although pediatric-specific PROMs exist, the present review indicates that they are not commonly used in clinical research.

The explanation for the lack of pediatric-specific PROMs in research may be that the Pedi-IKDC was first described by Kocher et al⁴¹ in 2011, the KOOS-Child in 2012 by Örtqvist et al,⁷⁰ and the HSS Pedi-FABS in 2013 by Fabricant et al.²² Hence, the present review may not give an accurate description of the use of these PROMs in clinical practice and research today. In support of this, a survey among European Society for Sports Traumatology, Knee Surgery and Arthroscopy (ESSKA) members revealed that 15% of the respondents reported the use of the Pedi-IKDC and 14% used the KOOS-Child.⁶⁴ Thus, it is reasonable to expect that the use of validated pediatric PROMs may be more common in the clinical setting and research today than our review indicates. Nevertheless, the recent consensus statement highlights the need for standardized, pediatric-specific PROMs to be applied in future studies evaluating the treatment of children and adolescents after ACL injury.² To our knowledge, no studies so far have evaluated the long-term outcomes after pediatric ACL injury, including the risk of developing knee osteoarthritis. Thus, the need for reliable and valid outcome measures that can be applied in both childhood and adulthood seem warranted.

Return to sport has been found to be one of the most important outcomes to adult patients undergoing ACL reconstruction.³⁸ In our review, return to sport following ACL injury treatment in children was reported in 41% of the included studies. In comparison, Makhni et al⁵³ found that return to sport following ACL injury in adults was reported in 24% of the studies included. The authors advocated for increased and enhanced reporting of return to sport from both a patient care perspective and a research perspective. It seems reasonable to advocate for this outcome measure in pediatric patients with ACL injury as well. A frequently used PROM to specifically measure psychological readiness to return to sport after ACL injury and reconstruction surgery is the Anterior Cruciate Ligament Return to Sport After Injury scale (ACL-RSI),⁹⁵ which was developed and published in 2008. In our review, this scale was identified as an outcome measure in 2 of the included studies—both published in 2018.^40,99 The psychological aspect of return to sport is important to include in the evaluation of the pediatric patient; however, to our best knowledge, the current version of the ACL-RSI was not developed for children and has not been validated in pediatric patients, which is why future work should address this issue.

The most commonly used objective measures were knee joint laxity (76%) and ROM (41%). Knee joint laxity was most frequently measured with the Lachman test (32 studies) performed by the clinician and/or by the use of instruments (35 studies). Of the 35 studies reporting instrumented knee joint laxity, 29 studies used the KT instruments. As the KT instruments are not customized for children⁴⁴ and the variety of knee joint laxity testing techniques is substantial, the need for agreement on a reproducible and standardized objective measurement of ACL laxity in pediatric patients is emphasized. Furthermore, muscle strength testing in pediatric patients with ACL injury was reported in only 14 of 68 studies (21%), which seems remarkably low since both quadriceps and hamstring muscle strength is important for dynamic knee joint stabilization⁵ and likely important for future outcome after ACL injury.

It is highlighted in the pediatric ACL injury literature that it is essential when surgical treatment is undertaken to include appropriate measures of skeletal development both pre- and postoperatively.⁶⁴ In our review, the majority of the studies evaluated surgery as one of the applied treatments (65 of 68 studies), but growth disturbances were assessed in only 47 (69%) of these studies. In addition, the surgical techniques are highly diverse, and consensus could not be reached in a recent survey among orthopaedic surgeons in pediatric ACL injuries.⁶⁴ Thus, clinical guidelines on surgical treatment in relation to skeletal development seem difficult to provide.

ICF Domains

The analysis of how the identified outcome measures were related to the ICF model revealed that while the domain Body Function and Structure are well covered, only a few of the measures cover Activity Limitation and Participation Restriction. Table 2 provides insight that may be useful when selecting outcome measures in future studies. The IKDC/Pedi-IKDC captures all 3 ICF domains and is one of the instruments most commonly used to determine results following various knee procedures, including ACL reconstructions.²⁸ Oak et al⁶⁸ found no clinically significant difference between scores on the Pedi-IKDC versus the adult IKDC in adolescents aged 13 to 17 years. The authors concluded that if the adult questionnaire is used in adolescent patients, it can be consistently used during long-term follow-up. In contrast, it has been found that children had difficulties in comprehending several aspects of the adult form of the IKDC.³⁷ Thus, the question stands if the adult form can be used longitudinally or if the pediatric version (specifically validated for this age group⁷³) should be used during childhood and later exchanged with the adult version.

All the outcome measures that we identified in the present scoping review may be useful for describing knee function. However, as long as no standardized core set of outcome measures exists to evaluate pediatric patients with ACL injury, it is difficult to compare results across studies. The consensus statement by Ardern et al² addressed this issue, and it is likely that their recommendations will influence future outcome reporting in pediatric ACL injury research in the direction of more uniformity.

Conclusion

The 68 included studies showed that outcome measures developed for adults—namely, the IKDC Subjective Knee Form, the Lysholm scoring scale, and the Tegner activity rating scale—are the most frequently used PROMs in children with ACL injuries. Knee joint laxity was the most frequent reported objective parameter, with the KT instruments as the most commonly used method of assessing passive knee joint laxity. A mean of 8 outcome measures per study were reported, with no uniformity among studies in how to evaluate children after ACL injury. This highlights the need for establishing consensus over a standardized core set, covering all of the ICF health domains, for pediatric patients with ACL injury.

Footnotes

Acknowledgment

The authors would like to thank Linda Fernandes for verifying the ICF classification carried out by the research team.

The authors declared that there are no conflicts of interest in the authorship and publication of this contribution. AOSSM checks author disclosures against the Open Payments Database (OPD). AOSSM has not conducted an independent investigation on the OPD and disclaims any liability or responsibility relating thereto.

Notes

References

Akinleye

Sewick

Wells

. All-epiphyseal ACL reconstruction: a three-year follow-up. Int J Sports Phys Ther. 2013;8(3):300–310.

Ardern

Ekås

Grindem

et al. 2018 International Olympic Committee consensus statement on prevention, diagnosis and management of paediatric anterior cruciate ligament (ACL) injuries. Knee Surg Sports Traumatol Arthrosc. 2018;26(4):989–1010.

Arksey

O’Malley

. Scoping studies: towards a methodological framework. Int J Soc Res Methodol. 2005;8(1):19–32.

Astur

Castro

Bernardes

Cohen

. Unusual case of a surgically treated ACL tear in a 4-year-old patient. BMJ Case Rep. 2015;2015:bcr2015210817.

Bojsen-Møller

. Bevægeapparatets Anatomi. Vol 11. Udgave 2. Copenhagen, Denmark: Gyldendalske Boghandel, Nordisk Forlag AS; 1996.

Bonnard

Fournier

Babusiaux

Planchenault

Bergerault

de Courtivron

. Physeal-sparing reconstruction of anterior cruciate ligament tears in children: results of 57 cases using patellar tendon. J Bone Joint Surg Br. 2011;93(4):542–547.

Boyle

Butler

Queen

. Functional movement competency and dynamic balance after anterior cruciate ligament reconstruction in adolescent patients. J Pediatr Orthop. 2016;36(1):36–41.

Brien

Lorenzetti

Lewis

Kennedy

Ghali

. Overview of a formal scoping review on health system report cards. Implement Sci. 2010;5:2.

Briggs

Lysholm

Tegner

Rodkey

Kocher

Steadman

. The reliability, validity, and responsiveness of the Lysholm score and Tegner activity scale for anterior cruciate ligament injuries of the knee: 25 years later. Am J Sports Med. 2009;37(5):890–897.

10.

Brusalis

Lakomkin

Suryavanshi

et al. Clinical outcome reporting in youth ACL literature is widely variable. Orthop J Sports Med. 2017;5(8):2325967117724431.

11.

Calvo

Figueroa

Gili

et al. Transphyseal anterior cruciate ligament reconstruction in patients with open physes: 10-year follow-up study. Am J Sports Med. 2015;43(2):289–294.

12.

Cassard

Cavaignac

Maubisson

Bowen

. Anterior cruciate ligament reconstruction in children with a quadrupled semitendinosus graft: preliminary results with minimum 2 years of follow-up. J Pediatr Orthop. 2014;34(1):70–77.

13.

Cho

Jang

Son

. Transphyseal anterior cruciate ligament reconstruction in a skeletally immature knee using anterior tibialis allograft. Orthopedics. 2011;34(5):397.

14.

Chotel

Henry

Seil

Chouteau

Moyen

Bérard

. Growth disturbances without growth arrest after ACL reconstruction in children. Knee Surg Sports Traumatol Arthrosc. 2010;18(11):1496–1500.

15.

Collins

Van Valin

. Anterior cruciate ligament tear in a 7-year-old athlete. Am J Orthop (Belle Mead, NJ). 2013;42(1):33–36.

16.

Cordasco

Mayer

Green

. All-inside, all-epiphyseal anterior cruciate ligament reconstruction in skeletally immature athletes: return to sport, incidence of second surgery, and 2-year clinical outcomes. Am J Sports Med. 2017;45(4):856–863.

17.

Courvoisier

Grimaldi

Plaweski

. Good surgical outcome of transphyseal ACL reconstruction in skeletally immature patients using four-strand hamstring graft. Knee Surg Sports Traumatol Arthrosc. 2011;19(4):588–591.

18.

Cruz

Jr Fabricant

McGraw

Rozell

Ganley

Wells

. All-epiphyseal ACL reconstruction in children: review of safety and early complications. J Pediatr Orthop. 2017;37(3):204–209.

19.

Dei Giudici

Fabbrini

Garro

Arima

Gigante

Tucciarone

. Arthroscopic transphyseal anterior cruciate ligament reconstruction in adolescent athletes. J Orthop Surg (Hong Kong). 2016;24(3):307–311.

20.

Demange

Camanho

. Nonanatomic anterior cruciate ligament reconstruction with double-stranded semitendinosus grafts in children with open physes: minimum 15-year follow-up. Am J Sports Med. 2014;42(12):2926–2932.

21.

Domzalski

Karauda

Grzegorzewski

Lebiedzinski

Zabierek

Synder

. Anterior cruciate ligament reconstruction using the transphyseal technique in prepubescent athletes: midterm, prospective evaluation of results. Arthroscopy. 2016;32(6):1141–1146.

22.

Fabricant

Robles

Downey-Zayas

et al. Development and validation of a pediatric sports activity rating scale: the Hospital for Special Surgery Pediatric Functional Activity Brief Scale (HSS Pedi-FABS). Am J Sports Med. 2013;41(10):2421–2429.

23.

Falciglia

Panni

Giordano

Aulisa

Guzzanti

. Anterior cruciate ligament reconstruction in adolescents (Tanner stages 2 and 3). Knee Surg Sports Traumatol Arthrosc. 2016;24(3):807–814.

24.

Faunø

Rahr-Wagner

Lind

. Risk for revision after anterior cruciate ligament reconstruction is higher among adolescents: results from the Danish Registry of Knee Ligament Reconstruction. Orthop J Sports Med. 2014;2(10):2325967114552405.

25.

Funahashi

Moksnes

Maletis

Csintalan

Inacio

Funahashi

. Anterior cruciate ligament injuries in adolescents with open physis: effect of recurrent injury and surgical delay on meniscal and cartilage injuries. Am J Sports Med. 2014;42(5):1068–1073.

26.

Geffroy

Lefevre

Thevenin-Lemoine

et al. Return to sport and re-tears after anterior cruciate ligament reconstruction in children and adolescents. Orthop Traumatol Surg Res. 2018;104(8):S183–S188.

27.

Goddard

Bowman

Salmon

Waller

Roe

Pinczewski

. Endoscopic anterior cruciate ligament reconstruction in children using living donor hamstring tendon allografts. Am J Sports Med. 2013;41(3):567–574.

28.

Greco

Anderson

Mann

et al. Responsiveness of the International Knee Documentation Committee Subjective Knee Form in comparison to the Western Ontario and McMaster Universities Osteoarthritis Index, modified Cincinnati Knee Rating System, and Short Form 36 in patients with focal articular cartilage defects. Am J Sports Med. 2010;38(5):891–902.

29.

Greenberg

Albaugh

Ganley

Lawrence

JTR

. Rehabilitation considerations for all epiphyseal ACL reconstruction. Int J Sports Phys Ther. 2012;7(2):185–196.

30.

Greenberg

Ganley

Lawrence

JTR

. Strength and functional performance recovery after anterior cruciate ligament reconstruction in preadolescent athletes. Sports Health. 2014;6(4):309–312.

31.

Hazle

Duby

. Anterior cruciate ligament injury diagnosis and management in a pediatric patient: a case report. Int J Sports Phys Ther. 2012;7(6):678–690.

32.

Edmonds

Chambers

Bastrom

Pennock

. Risk factors for early ACL reconstruction failure in pediatric and adolescent patients: a review of 561 cases. J Pediatr Orthop. 2018;38(7):388–392.

33.

Holwein

Hinterwimmer

Mayr

et al. Functional outcome after transphyseal anterior cruciate ligament reconstruction in young patients with open growth plates. Knee. 2016;23(6):1121–1132.

34.

Hui

Roe

Ferguson

Waller

Salmon

Pinczewski

. Outcome of anatomic transphyseal anterior cruciate ligament reconstruction in Tanner stage 1 and 2 patients with open physes. Am J Sports Med. 2012;40(5):1093–1098.

35.

Irrgang

Anderson

Boland

et al. Development and validation of the international knee documentation committee subjective knee form. Am J Sports Med. 2001;29(5):600–613.

36.

Irrgang

Snyder-Mackler

Wainner

Harner

. Development of a patient-reported measure of function of the knee. J Bone Joint Surg Am. 1998;80(8):1132–1145.

37.

Iversen

Lee

Connell

Andersen

Anderson

Kocher

. Validity and comprehensibility of the International Knee Documentation Committee Subjective Knee Evaluation form in Children. Scand J Med Sci Sports. 2010;20(1):e87–e95.

38.

Johnson

Smith

. Outcome measurement in the ACL deficient knee—what’s the score? Knee. 2001;8(1):51–57.

39.

Koch

Fucentese

Blatter

. Complications after epiphyseal reconstruction of the anterior cruciate ligament in prepubescent children. Knee Surg Sports Traumatol Arthrosc. 2016;24(9):2736–2740.

40.

Kocher

Heyworth

Fabricant

Tepolt

Micheli

. Outcomes of physeal-sparing ACL reconstruction with iliotibial band autograft in skeletally immature prepubescent children. J Bone Joint Surg Am. 2018;100(13):1087–1094.

41.

Kocher

Smith

Iversen

et al. Reliability, validity, and responsiveness of a modified International Knee Documentation Committee Subjective Knee Form (Pedi-IKDC) in children with knee disorders. Am J Sports Med. 2011;39(5):933–939.

42.

Kohl

Stutz

Decker

et al. Mid-term results of transphyseal anterior cruciate ligament reconstruction in children and adolescents. Knee. 2014;21(1):80–85.

43.

Koizumi

Kimura

Kamimura

Hagiwara

Takagishi

. The outcomes after anterior cruciate ligament reconstruction in adolescents with open physes. Knee Surg Sports Traumatol Arthrosc. 2013;21(4):950–956.

44.

Kumar

Ahearne

Hunt

. Transphyseal anterior cruciate ligament reconstruction in the skeletally immature: follow-up to a minimum of sixteen years of age. J Bone Joint Surg Am. 2013;95(1):e1.

45.

Larson

Heikes

Ellingson

et al. Allograft and autograft transphyseal anterior cruciate ligament reconstruction in skeletally immature patients: outcomes and complications. Arthroscopy. 2016;32(5):860–867.

46.

Lawrence

JTR

Bowers

Belding

Cody

Ganley

. All-epiphyseal anterior cruciate ligament reconstruction in skeletally immature patients. Clin Orthop Relat Res. 2010;468(7):1971–1977.

47.

Lawrence

JTR

West

Garrett

. Growth disturbance following ACL reconstruction with use of an epiphyseal femoral tunnel: a case report. J Bone Joint Surg Am. 2011;93(8):e39.

48.

Lee

Margalit

Nduaguba

Gunderson

Wells

. Obesity and recovery of muscle strength after anterior cruciate ligament reconstruction in pediatric patients. J Orthop Surg (Hong Kong). 2018;26(3):2309499018806631.

49.

Lemaitre

Salle de Chou

Pineau

et al. ACL reconstruction in children: a transphyseal technique. Orthop Traumatol Surg Res. 2014;100(4):S261–265.

50.

Lemos

Keating

Scott

Siwiec

. Physeal-sparing technique for femoral tunnel drilling in pediatric anterior cruciate ligament reconstruction using a posteromedial portal. Arthrosc Tech. 2013;2(4):e483–e490.

51.

Lopes Junior

Saggin

Matos do Nascimento

Kuhn

Saggin

Inacio

. Reconstruction of the anterior cruciate ligament in skeletally immature patients: an individualized approach. Rev Bras Ortop. 2014;49(3):252–259.

52.

Madelaine

Fournier

Sappey-Marinier

et al. Conservative management of anterior cruciate ligament injury in paediatric population: about 53 patients. Orthop Traumatol Surg Res. 2018;104(8):S169–S173.

53.

Makhni

Padaki

Petridis

et al. High variability in outcome reporting patterns in high-impact ACL literature. J Bone Joint Surg Am. 2015;97(18):1529–1542.

54.

Månsson

Sernert

Rostgard-Christensen

Kartus

. Long-term clinical and radiographic results after delayed anterior cruciate ligament reconstruction in adolescents. Am J Sports Med. 2015;43(1):138–145.

55.

Marx

Stump

Jones

Wickiewicz

Warren

. Development and evaluation of an activity rating scale for disorders of the knee. Am J Sports Med. 2001;29(2):213–218.

56.

Masaracchio

Comet

Godwin

. Management of an anterior cruciate ligament tear in a 5 year-old boy. Pediatr Phys Ther. 2015;27(3):302–310.

57.

Mauch

Arnold

Wirries

Mayer

Friederich

Hirschmann

. Anterior cruciate ligament reconstruction using quadriceps tendon autograft for adolescents with open physes—a technical note. Sports Med Arthrosc Rehabil Ther Technol. 2011;3(1):7.

58.

McCarthy

Graziano

Green

Cordasco

. All-epiphyseal, all-inside anterior cruciate ligament reconstruction technique for skeletally immature patients. Arthrosc Tech. 2012;1(2):e231–e239.

59.

Memeo

Pedretti

Miola

Albisetti

. Anterior cruciate ligament recostruction with bone-patellar tendon-bone autograft in Tanner 3 stage patients with open physes. J Pediatr Orthop B. 2012;21(5):415–420.

60.

Minick

Kiesel

Burton

Taylor

Plisky

Butler

. Interrater reliability of the functional movement screen. J Strength Cond Res. 2010;24(2):479–486.

61.

Moksnes

Engebretsen

Eitzen

Risberg

. Functional outcomes following a non-operative treatment algorithm for anterior cruciate ligament injuries in skeletally immature children 12 years and younger: a prospective cohort with 2 years follow-up. Br J Sports Med. 2013;47(8):488–494.

62.

Moksnes

Engebretsen

Risberg

. The current evidence for treatment of ACL injuries in children is low: a systematic review. J Bone Joint Surg Am. 2012;94(12):1112–1119.

63.

Moksnes

Engebretsen

Risberg

. Prevalence and incidence of new meniscus and cartilage injuries after a nonoperative treatment algorithm for ACL tears in skeletally immature children: a prospective MRI study. Am J Sports Med. 2013;41(8):1771–1779.

64.

Moksnes

Engebretsen

Seil

. The ESSKA paediatric anterior cruciate ligament monitoring initiative. Knee Surg Sports Traumatol Arthrosc. 2016;24(3):680–687.

65.

Müller

Biedert

Hefti

Jakob

Munzinger

Stäubli

. OAK knee evaluation: a new way to assess knee ligament injuries. Clin Orthop Relat Res. 1988;232:37–50.

66.

Nelson

Chen

Love

Davis

Maletis

Funahashi

. A comparison of revision and rerupture rates of ACL reconstruction between autografts and allografts in the skeletally immature. Knee Surg Sports Traumatol Arthrosc. 2016;24(3):773–779.

67.

Nikolaou

Kalliakmanis

Bousgas

Zourntos

. Intraarticular stabilization following anterior cruciate ligament injury in children and adolescents. Knee Surg Sports Traumatol Arthrosc. 2011;19(5):801–805.

68.

Oak

O’Rourke

Strnad

et al. Statistical comparison of the pediatric versus adult IKDC subjective knee evaluation form in adolescents. Am J Sports Med. 2015;43(9):2216–2221.

69.

Örtqvist

Iversen

Janarv

P-M

Broström

Roos

. Psychometric properties of the Knee injury and Osteoarthritis Outcome Score for Children (KOOS-Child) in children with knee disorders. Br J Sports Med. 2014;48(19):1437–1446.

70.

Örtqvist

Roos

Brostrom

Janarv

P-M

Iversen

. Development of the Knee Injury and Osteoarthritis Outcome Score for children (KOOS-Child): comprehensibility and content validity. Acta Orthop. 2012;83(6):666–673.

71.

Oxford Centre for Evidence-Based Medicine. Levels of evidence (March 2009). https://www.cebm.net/2009/06/oxford-centre-evidence-based-medicine-levels-evidence-march-2009/. Published June 11, 2009. Accessed April 1, 2018.

72.

Pennock

Chambers

Turk

Parvanta

Dennis

Edmonds

. Use of a modified all-epiphyseal technique for anterior cruciate ligament reconstruction in the skeletally immature patient. Orthop J Sports Med. 2018;6(7):2325967118781769.

73.

Phillips

Carsen

Vasireddi

Mulpuri

. Use of patient-reported outcome measures in pediatric orthopaedic literature. J Pediatr Orthop. 2018;38(8):393–397.

74.

Placella

Bartoli

Peruzzi

Speziali

Pace

Cerulli

. Return to sport activity after anterior cruciate ligament reconstruction in skeletally immature athletes with manual drilling original all inside reconstruction at 8 years follow-up. Acta Orthop Traumatol Turc. 2016;50(6):635–638.

75.

Raad

Thevenin Lemoine

Berard

Laumonerie

Sales de Gauzy

Accadbled

. Delayed reconstruction and high BMI z score increase the risk of meniscal tear in paediatric and adolescent anterior cruciate ligament injury. Knee Surg Sports Traumatol Arthrosc. 2019;27(3):905–911.

76.

Redler

Brafman

Trentacosta

Ahmad

. Anterior cruciate ligament reconstruction in skeletally immature patients with transphyseal tunnels. Arthroscopy. 2012;28(11):1710–1717.

77.

Robert

Casin

. Valgus and flexion deformity after reconstruction of the anterior cruciate ligament in a skeletally immature patient. Knee Surg Sports Traumatol Arthrosc. 2010;18(10):1369–1373.

78.

Roberti di Sarsina

Macchiarola

Signorelli

et al. Anterior cruciate ligament reconstruction with an all-epiphyseal “over-the-top” technique is safe and shows low rate of failure in skeletally immature athletes. Knee Surg Sports Traumatol Arthrosc. 2019;27(2):498–506.

79.

Roos

Lohmander

Ekdahl

Beynnon

. Knee injury and Osteoarthritis Outcome Score (KOOS)—development of a self-administered outcome measure. J Orthop Sports Phys Ther. 1998;28:88–96.

80.

Schmale

Kweon

Larson

Bompadre

. High satisfaction yet decreased activity 4 years after transphyseal ACL reconstruction. Clin Orthop Relat Res. 2014;472(7):2168–2174.

81.

Severyns

Lucas

Jallageas

et al. ACL reconstruction in 11 children using the Clocheville surgical technique: objective and subjective evaluation. Orthop Traumatol Surg Res. 2016;102(4):S205–S208.

82.

Shaw

Finch

. Trends in pediatric and adolescent anterior cruciate ligament injuries in Victoria, Australia 2005-2015. Int J Environ Res Public Health. 2017;14(6):E599.

83.

Shifflett

Green

Widmann

Marx

. Growth arrest following ACL reconstruction with hamstring autograft in skeletally immature patients: a review of 4 cases. J Pediatr Orthop. 2016;36(4):355–361.

84.

Siebold

Takada

Feil

Dietrich

Stinton

Branch

. Anatomical “C”-shaped double-bundle versus single-bundle anterior cruciate ligament reconstruction in pre-adolescent children with open growth plates. Knee Surg Sports Traumatol Arthrosc. 2016;24(3):796–806.

85.

Smith

Yasen

Palmer

Lord

Britton

Wilson

. Paediatric ACL repair reinforced with temporary internal bracing. Knee Surg Sports Traumatol Arthrosc. 2016;24(6):1845–1851.

86.

Sorensen

Davidsen

Gudex

Pedersen

Bronnum-Hansen

. Danish EQ-5D population norms. Scand J Public Health. 2009;37(5):467–474.

87.

Streich

Barié

Gotterbarm

Keil

Schmitt

. Transphyseal reconstruction of the anterior cruciate ligament in prepubescent athletes. Knee Surg Sports Traumatol Arthrosc. 2010;18(11):1481–1486.

88.

Sueyoshi

Emoto

Yato

. Correlation between Single Assessment Numerical Evaluation score and Lysholm score in primary total knee arthroplasty patients. Arthroplasty Today. 2017;4(1):99–102.

89.

Sugimoto

Heyworth

Collins

Fallon

Kocher

Micheli

. Comparison of lower extremity recovery after anterior cruciate ligament reconstruction with transphyseal hamstring versus extraphyseal iliotibial band techniques in skeletally immature athletes. Orthop J Sports Med. 2018;6(4):2325967118768044.

90.

Tegner

Lysholm

. Rating systems in the evaluation of knee ligament injuries. Clin Orthop Relat Res. 1985;198:43–49.

91.

Vavken

Tepolt

Kocher

. Concurrent meniscal and chondral injuries in pediatric and adolescent patients undergoing ACL reconstruction. J Pediatr Orthop. 2018;38(2):105–109.

92.

Volpi

Cervellin

Bait

et al. Trans-physeal anterior cruciate ligament reconstruction in adolescents. Knee Surg Sports Traumatol Arthrosc. 2016;24(3):707–711.

93.

Wall

Ghattas

Eismann

Myer

Carr

. Outcomes and complications after all-epiphyseal anterior cruciate ligament reconstruction in skeletally immature patients. Orthop J Sports Med. 2017;5(3):2325967117693604.

94.

Ware

Sherbourne

. The MOS 36-Item Short-Form Health Survey (SF-36): I. Conceptual framework and item selection. Med Care. 1992;30(6):473–483.

95.

Webster

Feller

Lambros

. Development and preliminary validation of a scale to measure the psychological impact of returning to sport following anterior cruciate ligament reconstruction surgery. Phys Ther Sport. 2008;9(1):9–15.

96.

Werner

Yang

Looney

Gwathmey

. Trends in pediatric and adolescent anterior cruciate ligament injury and reconstruction. J Pediatr Orthop. 2016;36(5):447–452.

97.

Whittaker

Woodhouse

Nettel-Aguirre

Emery

. Outcomes associated with early post-traumatic osteoarthritis and other negative health consequences 3-10 years following knee joint injury in youth sport. Osteoarthritis Cartilage. 2015;23(7):1122–1129.

98.

Willimon

Jones

Herzog

May

Leake

Busch

. Micheli anterior cruciate ligament reconstruction in skeletally immature youths: a retrospective case series with a mean 3-year follow-up. Am J Sports Med. 2015;43(12):2974–2981.

99.

Willson

Kostyun

Milewski

Nissen

. Anterior cruciate ligament reconstruction in skeletally immature patients: early results using a hybrid physeal-sparing technique. Orthop J Sports Med. 2018;6(2):2325967118755330.

100.

World Health Organization. International Classification of Functioning, Disability and Health (ICF). http://www.who.int/classifications/icf/en/. Accessed November 28, 2017.

101.

Yoo

Kocher

Micheli

. Growth plate disturbance after transphyseal reconstruction of the anterior cruciate ligament in skeletally immature adolescent patients: an MR imaging study. J Pediatr Orthop. 2011;31(6):691–696.

102.

Zimmerman

Jauregui

Riis

Tuten

. Symmetric limb overgrowth following anterior cruciate ligament reconstruction in a skeletally immature patient. J Pediatr Orthop B. 2015;24(6):530–534.