Managing anterior cruciate ligament deficiency in the skeletally immature individual: a systematic review of the literature

Primary Proximal ACL Repair: A Biomechanical Evaluation of Different Arthroscopic Suture Configurations

Purpose: Several suture techniques have been described in the past for direct ACL repair with poor healing capacity and a high re-rupture rate. Therefore, we investigated a refixation technique for acute primary proximal ACL repair. The purpose of this study is to compare the biomechanical properties of different suture configurations using a knotless anchor. Methods: In this study, 35 fresh-frozen porcine knees underwent proximal ACL refixation. First, in 10 porcine femora, the biomechanical properties of the knotless anchor, without the ligament attached, were tested. Then, three different suture configurations were evaluated to reattach the remaining ACL. Using a material testing machine, the structural properties were evaluated for cyclic loading followed by loading to failure. Results: The ultimate failure load of the knotless anchor was 198, 76 N ± 23, 4 N significantly higher than all of the tested ACL suture configurations. Comparing the different configurations, the modified Kessler–Bunnell suture showed significant superior ultimate failure load, with 81, 2 N ± 15, 6 N compared to the twofold and single sutures (50, 5 N ± 14 N and 37, 5 ± 3, 8 N). In cyclic loading, there was no significant difference noted for the different configurations in terms of stiffness and elongation. Conclusions: The results of this in vitro study show that when performing ACL suture using a knotless anchor, a modified Kessler–Bunnell suture provides superior biomechanical properties than a single and a twofold suture. Within this construct, no failure at the bone–anchor interface was seen. Clinical relevance: Since primary suture repair techniques of ACL tears have been abandoned because of inconsistent results, ACL reconstruction remains the gold standard of treating ACL tears. However, with the latest improvements in surgical techniques, instrumentation, hardware and imaging, primary ACL suture repair might be a treatment option for a select group of patients. By establishing an arthroscopic technique in which proximal ACL avulsion can be reattached, the original ACL can be preserved by using a knotless anchor and a threefold suture configuration. Nevertheless, this technique provides an inferior ultimate failure load compared to graft techniques, so a careful rehabilitation program must be followed if using this technique in vivo.

Combining Anterior Cruciate Ligament Reconstruction With Lateral Extra-Articular Procedures in Skeletally Immature Patients Is Safe and Associated With a Low Failure Rate

Purpose

To analyze the rates of graft ruptures and growth disorders, the level of return to sport, and the clinical results of 2 lateral extra-articular procedures in growing children.

Methods

This study was a retrospective, single-center study of patients undergoing anterior cruciate ligament (ACL) surgery combined with 2 different lateral extra-articular procedures (anatomic reconstruction with a gracilis graft or modified Lemaire technique with a strip of fascia lata). The measurements of side-to-side anterior laxity and pivot shift were performed preoperatively and at the last follow-up. The sports level and the complications rate were assessed. The minimal clinically important differences (MCID) and patient acceptable symptoms state threshold scores were calculated.

Results

Thirty-nine patients (40 ACLs) were included (20 anatomic and 20 modified Lemaire) at an average follow-up of 57 months ± 10 [42-74]. One patient (2.5%) was lost to follow-up. The mean age at surgery was 13.8 ± 1.4 years old [9.8; 16.5]. One graft failure was reported (2.6% [0.06-13.5]) at 35.6 months after surgery. Two cases (5.4%) of femoral overgrowth were observed, and one of them required distal femoral epiphysiodesis. Ninety-two percent of the patients returned to sports. At the final follow-up, side-to-side anterior laxity was significantly improved, and no residual pivot shift was recorded in 95% of patients. Eighty-nine percent of the patients presented a Pedi-International Knee Documentation Committee score greater than the MCID postoperatively, and 77% presented a Lysholm score greater than the MCID.

Conclusions

This series of ACL reconstructions combined with 2 different lateral extra-articular procedures in skeletally immature patients demonstrated promising findings. The low rate of observed complications, including graft rupture and growth disturbance, is encouraging, but the small study population and lack of comparative group precludes reliable conclusions.

Level of Evidence

IV, therapeutic case series.

17-Year Results following Transepiphyseal Anterior Cruciate Ligament Reconstruction in Children and Adolescents

OBJECTIVE

Rupture of the anterior cruciate ligament (ACL) in childhood and adolescence is a serious injury. It is now known that conservative therapy of an unstable knee joint in childhood or adolescence under can lead to poor subjective and objective results. The aim of this study is to record long-term results after transepiphyseal ACL reconstruction using autologous hamstring tendons and extracortical fixation in childhood and adolescence with open physes - at least 15 years after surgery.

METHODS

Our internal registry was used to identify all patients who received surgical treatment of an acl tear during childhood and adolescence by transepiphyseal acl reconstruction more than 15 years previously. In these patients, the International Knee Documentation Committee for Subjective Knee Form (IKDCsubj.), Knee Injury and Osteoarthritis Outcome Score (KOOS), Tegner Activity Score (TAS) and Lysholm Score were collected, and clinical and magnetic resonance imaging (MRI) examinations were performed.

RESULTS

A total of 22 patients were identified, 5 of whom could not be contacted. The mean age at the time of surgery was 13.1 years, and the mean follow-up time was 17.4 years. In 3 patients, a traumatic tear was observed with subsequent reconstruction of the ACL. None of the included patients showed a growth disorder during the course of the study. The IKDC_subj. was 92.4 ± 14.7 (48 - 100), the Lysholm score was 87.9 ± 16.9 (34 - 100), the TAS was 5.7 ± 2.3 (3 - 9) and the pain level based on VAS was 3.5 ± 2.6 (1 - 8) points. The values showed subjective and objective deterioration compared to the 10-year results, with no statistical significance. The following subscores were reported for the KOOS: KOOS_pain 90.9 ± 17.6 (28 - 100); KOOS_symptom 82.9 ± 22.6 (11 - 100); KOOOS_ADL 94.3 ± 13.7 (44 - 100); KOOS_Sport 80.3 ± 26.4 (15 - 100); KOOS_QOL 80.9 ± 25.8 (0 - 100). 13 of the 17 patients could also be clinically and radiologically examined. In 92% of patients, an intact acl reconstruction was found without evidence of cartilage or meniscus damage. The mean lateral difference in the KT-1000 measurement was 1.5 mm.

CONCLUSION

ACL reconstruction in childhood and adolescence provides good functionality and stability of the knee joint over the long term. Secondary signs of osteoarthritis can only be detected in isolated cases by MRI. ACL reconstruction using the transepiphyseal technique can be considered the method of choice for open growth plate knee joints.

Influential Articles on Pediatric and Adolescent Anterior Cruciate Ligament Injuries: A Bibliometric Analysis

BACKGROUND

The understanding of pediatric anterior cruciate ligament (ACL) injuries and optimal treatment has evolved significantly. Influential articles have been previously evaluated using article citations to determine impact.

PURPOSE

To identify and characterize the 50 most cited and recent influential articles relating to pediatric and adolescent ACL injuries, to examine trends in publication characteristics, and to evaluate correlations of study citations with quality of evidence.

STUDY DESIGN

Cross-sectional study.

METHODS

The top 50 most cited articles on pediatric and adolescent ACL injuries were gathered using the Web of Science and Scopus online databases by averaging the number of citations from each database. Articles from recent years were also aggregated and sorted by citation density (citations/year). Publication and study characteristics were recorded. Level of evidence and methodologic quality were assessed where applicable using the modified Coleman Methodology Score (mCMS), modified Jadad scale, and Methodological Index for Non-Randomized Studies (MINORS). Spearman correlation was used to evaluate the association between citation data and level of evidence or methodologic quality scorings.

RESULTS

The top 50 cited papers had a mean of 117.5 ± 58.8 citations (range, 58.5-288.5 citations), with a mean citation density of 9.4 ± 5.4 citations per year (range, 2.9-25.8 citations/year); 80% were published in 2000 or later, and 6% were considered basic science. Articles were mainly level 4 evidence (27/42; 64.3%), and none was level 1. There were moderate, significant associations between publication year and level of evidence (r S = -0.45; P = .0030) and citation density and publication year (r S = 0.59; P < .001). Mean methodologic quality scores were as follows: mCMS, 53 ± 7.2 (range, 39-68); modified Jadad scale, 3.2 ± 1.1 (range, 2-6); and MINORS, 11.2 ± 3.2 (range, 6-20). There was a significant, strong correlation between rank of mean citations and modified Jadad scale (r S = 0.76; P < .0001), suggesting poorer score associated with more mean citations.

CONCLUSION

Influential articles on pediatric and adolescent ACL injuries were relatively recent, with a low proportion of basic science-type articles. Most of the studies had a lower evidence level and poor methodologic quality scores. Higher methodologic quality did not correlate positively with citation data.

Quadriceps Strength Is Influenced by Skeletal Maturity in Adolescents Recovering From Anterior Cruciate Ligament Reconstruction

BACKGROUND

Anterior cruciate ligament injuries and anterior cruciate ligament reconstructions (ACLRs) are common, especially in adolescent patients. Recovery of strength, jumping performance, and perceived/subjective function are often used to make a return to sports decisions after injury. It is unknown how skeletal maturity may influence strength recovery after ACLR. The purpose of this study was to compare the strength and patient-reported outcomes in adolescent ACLR patients with and without open distal femur and proximal tibia physes.

METHODS

One hundred seventeen consecutive patients under the age of 18 were referred for routine strength and subjective outcomes evaluation following ACLR, 100 were included in the final analyses after excluding those with prior injuries, those tested outside for 4 to 12 month postoperative window, and those with incomplete clinical data. All study patients completed patient-reported outcomes, and underwent isometric and isokinetic testing of knee extensor and flexor strength to calculate normalized peak torque and limb symmetry. Statistical analyses were performed on all outcomes data using a 2×2 (physeal status: open, closed; and sex: male, female) with analysis of covariance where age and preoperative activity level were used as covariates.

RESULTS

A significant interaction between sex and physeal status for isokinetic knee extension peak torque and isometric knee extension peak torque, and limb symmetry index was found. This indicated that males with open physes were stronger and more symmetric than males with closed physes and females with open physes at ~6 months post-ACLR. There were no differences between sexes for patients with closed physes. No interactions were observed for flexion strength. Male patients and patients with open physes had higher perceived knee function compared with their corresponding counterparts.

CONCLUSIONS

After ACLR, adolescent patients with open physes had higher quadriceps strength compared with patients with closed physes. Overall, those skeletally less mature patients actually fared better on the functional strength tests, suggesting that functional recovery is not hindered by the presence of an incompletely closed physis.

LEVEL OF EVIDENCE

Level III-retrospective comparative study.

The incidence of paediatric ACL injury is increasing in Finland

PURPOSE

Anterior cruciate ligament (ACL) injury is a common knee injury in paediatric and adolescent patients. The population-based incidence of paediatric ACL injury is, however, unknown. Recent studies suggest increased ACL injury rates among adolescents, especially in active, sports-participating population. The purpose of this study was to investigate the population-based incidence rates of ACL injuries and trends in paediatric ACL reconstruction surgery.

METHOD

All ACL injuries were identified (ICD-10 diagnosis code S83.5) leading to hospitalisation or surgery using validated Finnish National Hospital Discharge Register (NHDR) data from 1997 to 2014. The sample comprised 19,961,205 Finnish residents aged less than 18 years at the time of injury. Hospital admissions with the diagnosis code S83.5 were analysed more thoroughly including, sex, age and the need for surgical interventions.

RESULTS

During the 18-year study period, 4725 subjects of the study population had sustained an ACL injury. The total ACL injury incidence in study population was 23.3 per 100,000 person-years. The median age of the patients at the time of injury was 16 years (range 4-17). The incidence of ACL injury increased with age, and the highest incidence was observed among 17-year old (113.5 per 100,000 person-years). Incidence rate did not differ between genders. From the total ACL injury population of 4725 hospitalisations, 3168 (67.0%) underwent ACL reconstruction, of which 2988 (94.3%) were treated with arthroscopic reconstruction and 180 (5.6%) with open surgery. In addition, 1557 (33.0%) were treated non-operatively without ACL reconstruction. The annual incidence of ACL injuries in the Finnish paediatric population has increased during the past 15 years. The lowest incidence rate was seen in 1999 (incidence of 17.7 per 100,000 person-years, 195 ACL injuries) and the highest in 2011 (incidence of 31.5 per 100,000 person-years, 346 ACL injuries). The highest increase in ACL injuries was seen in girls aged 13-15 years, with an increase of 143%.

CONCLUSION

ACL injury is not a negligible knee injury in the paediatric population. The incidence of paediatric ACL injury has increased during the past 15 years. Moreover, a twofold increase in incidence of paediatric ACL injury was noted during the last 10 years of the study period. Incidence rates among male and female paediatric patients were comparable.

LEVEL OF EVIDENCE

III.

Delayed reconstruction and high BMI z score increase the risk of meniscal tear in paediatric and adolescent anterior cruciate ligament injury

PURPOSE

The purpose of this study was to identify epidemiologic risk factors for secondary meniscal tears in paediatric and adolescent patients who sustain an anterior cruciate ligament (ACL) tear. The hypothesis was that delayed reconstruction and elevated BMI z score, increase the risk for secondary meniscal tears.

METHODS

A prospective, descriptive and analytical study of consecutively accrued children and adolescents with an ACL tear was performed. One hundred and sixty subjects (114 males and 46 females) were identified between 2006 and 2015 at one institution. The age range was between 7 and 19 years. Fifteen parameters were recorded and analysed: age at initial trauma, initial trauma circumstance, sex, BMI z score, affected side, type of sport, Tegner score, athletic level, time to MRI, time to first referral, time to surgery, age at surgery, attempted non-operative treatment, operative report and associated meniscal tear. These meniscal lesions could be diagnosed by an MRI and / or during surgery.

RESULTS

Out of the 160 cases, 143 were treated surgically and 17 cases non-operatively. Median corrected BMI z score was 0.5 (range - 1.8 to 4.7). 41.9% had one or more meniscal lesions. 55 patients were initially treated non-operatively, of which 39 patients were secondarily operated. There was a positive relationship between meniscal lesion and: BMI z score (p = 0.0364), attempted non-operative treatment (p = 0.001) and time to surgery (p = 0.002). The median time to ACL reconstruction was 229 days for patients with secondary meniscal lesions.

CONCLUSIONS

Patients with ACL tears treated non-operatively developed secondary meniscal lesions requiring delayed surgical management. There was a positive correlation between BMI z score and secondary meniscal lesions. Thus, early ACL reconstruction is advocated in young athletes.

LEVEL OF EVIDENCE

Retrospective comparative study, Level III.

Current Strategies and Future Directions to Optimize ACL Reconstruction in Adolescent Patients

The incidence of anterior cruciate ligament (ACL) injuries in the pediatric population has risen in recent years. These injuries have historically presented a management dilemma in skeletally immature patients with open physes and significant growth remaining at time of injury. While those nearing skeletal maturity may be treated with traditional, transphyseal adult techniques, these same procedures risk iatrogenic damage to the growth plates and resultant growth disturbances in younger patients with open physes. Moreover, conservative management is non-optimal as significant instabilities of the knee remain. Despite the development of physeal-sparing reconstructive techniques for younger patients, there remains debate over which procedure may be most suitable on a patient to patient basis. Meanwhile, the drivers behind clinical and functional outcomes following ACL reconstruction remain poorly understood. Therefore, current strategies are not yet capable of optimizing surgical ACL reconstruction on an individualized basis with absolute confidence. Instead, aims to improve surgical treatment of ACL tears in skeletally immature patients will rely on additional approaches in the near future. Namely, finite element models have emerged as a tool to model complex knee joint biomechanics. The inclusion of several individualized variables such as bone age, three dimensional geometries around the knee joint, tunnel positioning, and graft tension collectively present a possible means of better understanding and even predicting how to enhance surgical decision-making. Such a tool would serve surgeons in optimizing ACL reconstruction in the skeletally immature individuals, in order to improve clinical outcomes as well as reduce the rate of post-operative complications.

"I never made it to the pros…" Return to sport and becoming an elite athlete after pediatric and adolescent anterior cruciate ligament injury-Current evidence and future directions

The management of anterior cruciate ligament (ACL) injuries in the skeletally immature and adolescent patient remains an area of controversy in sports medicine. This study, therefore, summarizes and discusses the current evidence related to treating pediatric and adolescent patients who sustain an ACL injury. The current literature identifies a trend towards ACL reconstruction as the preferred treatment option for ACL injuries in the young, largely justified by the risk of further structural damage to the knee joint. Worryingly, a second ACL injury is all too common in the younger population, where almost one in every three to four young patients who sustain an ACL injury and return to high-risk pivoting sport will go on to sustain another ACL injury. The clinical experience of these patients emphasizes the rarity of an athlete who makes it to elite level after a pediatric or adolescent ACL injury, with or without reconstruction. If these patients are unable to make it to an elite level of sport, treatment should possibly be modified to take account of the risks associated with returning to pivoting and strenuous sport. The surveillance of young athletes may be beneficial when it comes to reducing injuries. Further research is crucial to better understand specific risk factors in the young and to establish independent structures to allow for unbiased decision-making for a safe return to sport after ACL injury. Level of evidence V.

Anterior cruciate ligament reconstruction in skeletally immature patients : a systematic review

AIMS

Different methods of anterior cruciate ligament (ACL) reconstruction have been described for skeletally immature patients before closure of the growth plates. However, the outcome and complications following this treatment remain unclear. The aim of this systematic review was to analyse the outcome and complications of different techniques which may be used for reconstruction of the ACL in these patients.

MATERIALS AND METHODS

We performed a systematic review of the literature according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. This involved a comprehensive search of PubMed, Medline, CINAHL, Cochrane, Embase and Google Scholar databases using the following combinations of keywords, "knee", "anterior cruciate ligament", "reconstruction", "injury", "children", "adolescent", "skeletally immature", "open physis" and "surgery".

RESULTS

A total of 53 studies met the inclusion criteria and were included for analysis. The overall rate of disturbance of growth after ACL reconstruction was 2.6%, with no statistical difference between transphyseal and physeal-sparing techniques. Physeal-sparing techniques had a lower rate of post-operative complications compared with transphyseal techniques (p = 0.0045). Outcomes assessed were Lysholm score, International Knee Documentation Committee (IKDC) score, the IKDC grade, the Tegner score and the KT-1000. Both techniques had similar clinical outcomes.

CONCLUSIONS

This review reveals low rates of disturbance of growth after ACL reconstruction in skeletally immature patients. Although limited, the available evidence did not support any particular surgical technique when considering disturbance of growth or clinical outcome. Further randomised controlled trials are needed to investigate the efficacy of differing surgical techniques on outcomes in skeletally immature patients. Cite this article: Bone Joint J 2017;99-B:1053-60.

Pediatric ACL Injuries: A Review of Current Concepts

Background:

The number of anterior cruciate ligament (ACL) injuries reported in skeletally immature athletes has increased over the past 2 decades. The reasons for this increased rate include the growing number of children and adolescents participating in competitive sports vigorous sports training at an earlier age and greater rate of diagnosis because of increased awareness and greater use of advanced medical imaging. There is a growing need for a consensus and evidence based approach for management of these injuries to frame a dedicated age specific treatment strategy.

Methods:

This article does a systematic evidence based literature review of management of Pediatric ACL injuries seen in several forms: tibial eminence avulsion fractures partial ACL tears and full thickness ligament tears and its outcome analysis.

Results:

The mechanism of Safe and effective surgical techniques for children and adolescents with ACL injuries continues to evolve. The numerous age matched techniques are extensively discussed. Neuromuscular training can reduce the risk of ACL injury in adolescent girls.

Conclusion:

This review outlines the current state of knowledge on diagnosis treatment and prevention of ACL injuries in children and adolescents and helps in guiding the treatment through a dedicated algorithm.

ACL Tears in School-Aged Children and Adolescents Over 20 Years

BACKGROUND

Anterior cruciate ligament (ACL) tears are thought to occur with increasing frequency in young patients. No study has shown increased incidence over time. We hypothesized the incidence of ACL tears in young patients has increased over the past 20 years.

METHODS

This descriptive epidemiology study is a retrospective review of insurance billing data of all patients aged 6 to 18 years with Current Procedural Terminology, Fourth Revision codes for ACL tear and reconstruction or International Classification of Diseases, Ninth Revision, Clinical Modification codes from 1994 to 2013. Injuries were normalized to persons per year enrolled in the insurance database based on age and sex. Analysis was performed based on sex and age (6-14, 15-16, and 17-18 years).

RESULTS

The rate of ACL tears per 100 000 person-years averaged 121 ± 19 (range 92-151). All trends increased significantly except for the male 6- to 14-year-old and 17- to 18-year-old age groups. Overall there was an annual increase of 2.3%. Females had significantly higher incidence except in the 17- to 18-year-olds. Females peaked at age 16 years and males at age 17 years, with rates of 392 ACL tears and 422 ACL tears per 100 000 person-years, respectively.

CONCLUSIONS

The incidence of ACL tears in pediatric patients increased over the last 20 years. Females were at higher risk except in the 17- to 18-year -old group. Peak incidence is noted during high school years. These data help target the most at-risk patients for ACL prevention programs.

Tibial tunnel defect size as a risk factor in growth arrest following paediatric transphyseal anterior cruciate ligament reconstruction: an anatomical study

BACKGROUND

There is ongoing controversy regarding growth disturbances in younger patients undergoing anterior cruciate ligament reconstructions. Animal models have shown that an injury of 7-9% of the physeal area is a risk factor for growth disturbances.

METHODS

A total of 39 magnetic resonance imaging studies of the knee were examined. The proximal tibial physeal area was determined using a calibrated 'region of interest' ligature encompassing the tibial physis in the axial plane. The potential defect left by commonly used drill sizes was calculated as a percentage of the physeal area.

RESULTS

A 7-mm drill leaves a mean defect of 1.45% physeal area (range: 1.11-1.89%, SD: 0.28, 95% CI: ±0.09), 8-mm drill leaves a 1.84% mean defect (range: 1.43-2.49%, SD: 0.38, 95% CI: ±0.12) and a 9-mm drill leaves a 2.30% mean defect (range: 1.83-3.19%, SD: 0.58, 95% CI: ±0.17). At 55°, 7-mm drill leaves a mean defect of 1.96% (range: 1.32-2.28%, SD: 0.37, 95% CI: ±0.12), 8-mm drill leaves a mean defect of 2.19% (range: 1.71-2.95%, SD: 0.46, 95% CI: ±0.14) and a 9-mm drill leaves a mean defect of 2.76% (range: 2.16-3.73%, SD: 0.58, 95% CI: ±0.18). There was a statistically significant difference in the tunnel area with a change of drill angle (7-mm drill P = 0.005, 8-mm drill P = 0.001, 9-mm drill P = 0.001).

CONCLUSION

On the basis of this study in the context of animal model and observational evidence, the area of physeal injury using drill tunnels for anterior cruciate ligament reconstruction would not appear to contribute to potential growth disturbances.

ACL reconstruction in 11 children using the Clocheville surgical technique: Objective and subjective evaluation

INTRODUCTION

The over-the-top position of the femoral metaphyseal tunnel during extraphyseal ligament reconstruction of the anterior cruciate ligament (ACL) according to Clocheville may be responsible for negative anisometry. Until now, the follow-up of children operated using this pediatric technique was limited to screening for iatrogenic epiphysiodesis and the search for postoperative clinical instability. The objective of this study was to measure residual laxity using objective tests, to quantify muscle recovery, and to evaluate the quality of life of these patients in terms of the sports activities.

MATERIAL AND METHODS

Eleven patients with a mean age of 13.5years were seen at a mean 2.1years of follow-up. They underwent objective clinical tests (GNRB(®) arthrometer and CON-TREX(®) dynamometer) as well as subjective questionnaires (IKDC and KOOS).

RESULTS

No significant difference was found between the healthy knee and the operated knee for either the GNRB(®) at 134N (P=0.79) or at 200N (P=0.98). The CON-TREX(®) system allowed us to measure a median percentage of quadriceps recovery of 80.7% (range, 52.2-114.5) in terms of muscle power (60°/s) and 81.2% (range, 51.6-109.6) for muscle response (180°/s). The median subjective IKDC score was 94.73/100 (range, 73.68-98.93); 72.7% of the patients resumed competitive sports.

DISCUSSION

This study's lack of statistical power did not show a significant difference in terms of residual laxity at rest of GNRB(®) transplants, while a mean differential of +0.4mm was observed. Although pediatric transphyseal ligament reconstruction techniques are increasingly used, the Clocheville technique remains, in our opinion, an attractive surgical alternative in the youngest subjects, with no major risk of iatrogenic epiphysiodesis even though it is theoretically anisometric.

LEVEL OF EVIDENCE

IV.

Paediatric ACL repair reinforced with temporary internal bracing

PURPOSE

Instability following non-operative treatment of anterior cruciate ligament (ACL) rupture in young children frequently results in secondary chondral and/or meniscal injuries. Therefore, many contemporary surgeons advocate ACL reconstruction in these patients, despite the challenges posed by peri-articular physes and the high early failure rate. We report a novel management approach, comprising direct ACL repair reinforced by a temporary internal brace in three children.

METHODS

Two patients (aged 5 and 6 years) with complete proximal ACL ruptures and a third (aged seven) with an associated tibial spine avulsion underwent direct surgical repair, supplemented with an internal brace that was removed after 3 months.

RESULTS

Second-look arthroscopy, examination and imaging at 3 months confirmed knee stability and complete ACL healing in all cases. Normal activities were resumed at 4 months, and excellent objective measures of function, without limb growth disturbance, were noted beyond 2 years.

CONCLUSION

ACL repair in young children using this technique negates the requirement and potential morbidity of graft harvest and demonstrates the potential for excellent outcome as an attractive alternative to ACL reconstruction, where an adequate ACL remnant permits direct repair.

LEVEL OF EVIDENCE

IV.

A Systematic Summary of Systematic Reviews on the Topic of the Anterior Cruciate Ligament

BACKGROUND

There has been a substantial increase in the amount of systematic reviews and meta-analyses published on the anterior cruciate ligament (ACL).

PURPOSE

To quantify the number of systematic reviews and meta-analyses published on the ACL in the past decade and to provide an overall summary of this literature.

STUDY DESIGN

Systematic review; Level of evidence, 4.

METHODS

A systematic review of all ACL-related systematic reviews and meta-analyses published between January 2004 and September 2014 was performed using PubMed, MEDLINE, and the Cochrane Database. Narrative reviews and non-English articles were excluded.

RESULTS

A total of 1031 articles were found, of which 240 met the inclusion criteria. Included articles were summarized and divided into 17 topics: anatomy, epidemiology, prevention, associated injuries, diagnosis, operative versus nonoperative management, graft choice, surgical technique, fixation methods, computer-assisted surgery, platelet-rich plasma, rehabilitation, return to play, outcomes assessment, arthritis, complications, and miscellaneous.

CONCLUSION

A summary of systematic reviews on the ACL can supply the surgeon with a single source for the most up-to-date synthesis of the literature.

Prevention and rehabilitation of paediatric anterior cruciate ligament injuries

PURPOSE

To review the current knowledge on anterior cruciate ligament (ACL) injury prevention and ACL rehabilitation in individuals who have not yet reached musculoskeletal maturity.

METHODS

This is a narrative review based on a targeted and systematic literature search for paediatric ACL injury risk factors, injury prevention and rehabilitation.

RESULTS

The search strategies resulted in 119 hits on risk factor studies, 57 hits on prevention and 37 hits on rehabilitation. Modifiable risk factors for ACL injury are largely unknown in the paediatric population. ACL injury prevention using neuromuscular training is highly successful in the adolescent population, and existing injury prevention programmes are cost-effective. The efficacy of ACL injury prevention programmes in children is, however, investigated to a markedly lesser degree. Paediatric ACL injury rehabilitation is poorly described, although supervised active rehabilitation progressed through phases with functional milestones is generally encouraged.

CONCLUSION

Although limited, current evidence supports implementation of injury prevention programmes in female football players from the age of 12. Supervised active rehabilitation where progression is guided by functional milestones is also advocated. Future identification of modifiable risk factors is needed to design prevention programmes for younger children. There is a need for international multicentre studies on treatment algorithms and rehabilitation to increase knowledge on the short- and long-term outcomes following existing algorithms.

STUDY DESIGN

Narrative review, level III.

The ESSKA paediatric anterior cruciate ligament monitoring initiative

PURPOSE

To survey and describe the treatment of paediatric anterior cruciate ligament (ACL) injuries performed by orthopaedic surgeons affiliated with the European Society for Sports Traumatology, Knee Surgery and Arthroscopy (ESSKA).

METHODS

A closed e-survey was submitted to all registered members and affiliates of ESSKA in July 2013. All recipients were invited to participate in the survey by answering 34 questions online. The list of potential respondents was extracted from the ESSKA office database.

RESULTS

Invitation was sent to 2236 ESSKA members and affiliates, and received 491 (22%) unique responses. Among the respondents, 445 (91%) were orthopaedic surgeons, with 354 (72%) stating that they were involved in treatment of paediatric ACL injuries. The main findings were that there are substantial differences with regard to preferred treatment algorithms, surgical techniques and long-term follow-up procedures. The summed estimate of skeletally immature children with ACL injury seen by the responders in 2012 was minimum 1923 individuals, and a minimum of 102 clinically relevant post-operative growth disturbances were registered.

CONCLUSION

The present survey documents that the incidences of paediatric ACL injuries and idiopathic growth disturbances may be higher than previously estimated. Treatment algorithms and surgical techniques are highly diverse, and consensus could not be identified. It is worrying that only half the surgeons reported to follow-up children until skeletal maturity after surgical treatment. The results of this survey highlight the importance of international multicentre studies on paediatric ACL treatment and the development of an outcome registry to enable prospective data collections.

LEVEL OF EVIDENCE

IV.

Comparison of Growth Plate Violations for Transtibial and Anteromedial Surgical Techniques in Simulated Adolescent Anterior Cruciate Ligament Reconstruction

BACKGROUND

Increases in the rates and intensity of youth sports participation have led to an elevated incidence of anterior cruciate ligament (ACL) injuries and reconstruction in adolescents. Traditional reconstruction techniques in the skeletally immature patient may violate the growth plates and potentially lead to deformities.

HYPOTHESIS/PURPOSE

The purpose of this study was to compare the volume and location of femoral growth plate violations resulting from anteromedial (AM) and transtibial (TT) techniques in ACL reconstruction. The hypothesis was that the more oblique angle used in femoral tunnels drilled with the AM portal technique would produce larger and more lateral violations compared with those resulting from TT tunnels.

STUDY DESIGN

Controlled laboratory study.

METHODS

Growth plate disturbances were quantified by performing simulated reconstructions in computer models created from magnetic resonance imaging scans of the knees of 17 adolescent participants. Locations of tunnels drilled with simulated AM and TT portal techniques were specified by an orthopaedic surgeon blinded to the locations of the femoral physes in the knee models. Tunnels with lengths of 20, 25, and 30 mm were placed in each model using simulated drill diameters of 7, 8, and 9 mm in addition to a 4.5-mm tunnel breaching the lateral cortex. Normalized measures of the volume and laterality of violations were computed.

RESULTS

Tunnels drilled with the AM portal technique disrupted a significantly larger percentage of the physis (P = .007), but the difference was not substantial. Tunnels drilled with the AM portal technique produced violations that were more lateral in the physis than those drilled with the TT technique (P < .001). Tunnels drilled with the AM portal technique resulted in mean violations that were 5.1% ± 2.1% of the physis as compared with 4.7% ± 2.0% for TT tunnels. The mean value for a normalized measure of the laterality of the violation (L score) was 0.590 ± 0.115 for tunnels drilled with the AM portal technique and 0.290 ± 0.104 for TT tunnels. The AM approach produced 16 of 153 simulated reconstructions with growth plate violations greater than 8% compared with only 10 with the TT approach.

CONCLUSION

Results suggest that the AM approach produces growth plate violations that are larger and more lateral than the violations generated using the TT technique. AM approaches were more likely to remove more than 8% of the physeal volume, a level previously identified as posing a greater risk of growth disturbances. While the difference in the mean physeal volume removed between the approaches was small, the violations for the AM approach were much more lateral, a finding of potentially greater clinical significance.

CLINICAL RELEVANCE

As progressively younger patients are considered candidates for ACL reconstruction, knowledge of how variations in technique affect the developing knee is critical to preventing iatrogenic injuries.

Functional Movement Competency and Dynamic Balance After Anterior Cruciate Ligament Reconstruction in Adolescent Patients

BACKGROUND

Adolescent patients undergoing anterior cruciate ligament (ACL) reconstruction may not adequately recover safe movement patterns before returning to sport participation. The aims of this study were to assess functional movement and dynamic balance 9 months after primary ACL reconstruction in adolescent patients, and to assess for any maturity-specific differences that may guide rehabilitation strategies.

METHODS

A series of 39 adolescent patients who underwent primary, anatomic, transphyseal ACL reconstruction using hamstrings autograft from October 2009 to January 2013 were identified from a research database: 17 skeletally immature (SI) patients (mean age 13.6±1.6 y) and 22 skeletally mature (SM) patients (mean age 16.6±1.2 y). An adult reference population of 16 primary ACL reconstruction patients (mean age 27.4±4.0 y) was also identified. All patients followed a standardized operative and rehabilitation protocol. The 3 patient groups were compared 9 months postoperatively using the Functional Movement Screen (FMS) to assess movement competency and the Lower Quarter Y-Balance Test (LQYBT) to assess single-limb dynamic balance.

RESULTS

Nine months postoperatively, the FMS scores for all 3 groups indicated an increased risk for lower extremity injury (total score ≤14). With respect to specific movement patterns, the SI group displayed inferior active straight leg raise score (P=0.006) despite a lower incidence of pain with this movement. With the LQYBT, there was no significant difference in mean anterior (P=0.987), posterolateral (P=0.349), or posteromedial (P=0.870) reach asymmetry between the 3 groups; however, the adolescent groups demonstrated wider ranges of anterior reach asymmetry than the adult group indicating an increased risk for injury.

CONCLUSIONS

Adolescent patients undergoing primary ACL reconstruction do not consistently recover adequate functional movement patterns by 9 months postoperatively to permit a safe return to sport. We have identified unique functional movement deficits in SI and SM adolescents, which highlight the need for maturity-specific rehabilitation strategies for adolescent patients undergoing ACL reconstruction.

LEVEL OF EVIDENCE

Level IV—retrospective cohort

Inter- and intrarater reliability of four single-legged hop tests and isokinetic muscle torque measurements in children

PURPOSE

Single-legged hop tests and isokinetic muscle torque are common outcome measures in the evaluation of knee function. The reliability of the single-legged hop tests in children has not been documented. The aim was to examine inter- and intrarater reliability of four single-legged hop tests and isokinetic muscle torque measurements in children.

METHODS

Twenty-eight sports-active children (12.4 ± 0.3 years old) were tested three times in two test sessions separated by 1 week. They performed four single-legged hop tests and concentric isokinetic torque measurements during knee extension and flexion. Inter- and intrarater reliability were calculated using the intraclass correlation coefficient (ICC 2,1). Relative terms of the standard error of measurement (SEM %) and smallest real difference(SRD %) were emphasized to allow comparison between the different variables.

RESULTS

Twenty-six children were included for statistical analysis. ICCs for inter- and intrarater reliability were moderate to high for the hop tests (0.62-.91) and isokinetic measurements (0.76-0.87). SEMs % were low for the hop tests (3.9-7.4 %) and the isokinetic measurements (5.2-8.9 %). SRDs % were 20.5 % or less for the hop tests, 15.7 % or less for knee extension, and 24.6 % or less for knee flexion.

CONCLUSION

The single-legged hop tests and isokinetic muscle torque measurements demonstrated moderate-to high reliability with low measurement error in sports-active children. A change above 20.5 % for the single-legged hop tests, 15.7 % for knee extension, and 24.6 % for knee flexion is necessary to represent a real change in knee function. Level of evidence III.

Surgical-experimental principles of anterior cruciate ligament (ACL) reconstruction with open growth plates

Objective

To review surgical and animal experimental studies performed with open growth plates in relation with pediatric anterior cruciate ligament (ACL) reconstruction.

Backround

When it comes to the treatment of ACL injured children, there is a lack of current international guidelines, leaving the treating physicians with a therapeutic dilemma. A variety of surgical and animal experimental studies have been undertaken over the last decades in relation with open growth plates and ACL-reconstruction.

Method

Based on our own previous animal experimental data, we highlighted 15 specific points concerning pediatric ACL-reconstruction and reviewed additional literature concerning these individual items.

Results

Pediatric ACL-reconstruction could be proven to be safe in animal models. Growth abnormalities, risk factors and factors, which were specifically related to biological healing processes in children, were identified. From them surgical principles for safe pediatric ACL replacements can be deducted. Applying these principles through a correct technical execution of surgery may prevent clinically significant growth changes.

Conclusion

Over the last 2 decades it has been shown that a technically correct pediatric ACL reconstruction has little risk in creating clinically significant growth abnormalities. Animal experiments support this hypothesis despite the fact that the gained knowledge cannot be fully generalized to humans. More long time follow-up is needed to fully understand the complete risk factors related to ACL surgery with open growth plates.

Electronic supplementary material

The online version of this article (doi:10.1186/s40634-015-0027-z) contains supplementary material, which is available to authorized users.

Anterior cruciate ligament tears in children and adolescents: a meta-analysis of nonoperative versus operative treatment

BACKGROUND

Debate regarding the optimal initial treatment for anterior cruciate ligament (ACL) injuries in children and adolescents has not resulted in a clear consensus for initial nonoperative treatment or operative reconstruction.

HYPOTHESIS/PURPOSE

The purpose of this meta-analysis was to systematically analyze aggregated data from the literature to determine if a benefit exists for either nonoperative or early operative treatment for ACL injuries in the pediatric patient. The hypothesis was that combined results would favor early operative reconstruction with respect to posttreatment episodes of instability/pathological laxity, symptomatic meniscal tears, clinical outcome scores, and return to activity.

STUDY DESIGN

Meta-analysis.

METHODS

A literature selection process included the extraction of data on the following clinical variables: symptomatic meniscal tears, return to activities, clinical outcome scores, return to the operating room, and posttreatment instability/pathological laxity. A symptomatic meniscal tear was defined as occurring after the initial presentation, limiting activity, and requiring further treatment. Instability/pathological laxity was defined for the sake of this study as having an episode of giving way, a grade ≥2 Lachman/pivot-shift test result, or a side-to-side difference of >4 mm as measured by the KT-1000 arthrometer. All studies were evaluated using a formal study quality analysis. Meta-analysis was conducted for aggregated data in each category.

RESULTS

Six studies (217 patients) comparing operative to nonoperative treatment and 5 studies (353 patients) comparing early to delayed reconstruction were identified. Three studies reported posttreatment instability/pathological laxity; 13.6% of patients after operative treatment experienced instability/pathological laxity compared with 75% of patients after nonoperative treatment (P < .01). Two studies reported symptomatic meniscal tears; patients were over 12 times more likely to have a medial meniscal tear after nonoperative treatment than after operative treatment (35.4% vs 3.9%, respectively; P = .02). A significant difference in scores between groups was noted in 1 of 2 studies reporting International Knee Documentation Committee (IKDC) scores (P = .002) and in 1 of 2 studies reporting Tegner scores (P = .007). Two studies reported return to activity; none of the patients in the nonoperative groups returned to their previous level of play compared with 85.7% of patients in the operative groups (P < .01). Study quality analysis revealed that the majority of the studies were inconsistent in reporting outcomes.

CONCLUSION

Meta-analysis revealed multiple trends that favor early surgical stabilization over nonoperative or delayed treatment. Patients after nonoperative and delayed treatment experienced more instability/pathological laxity and inability to return to previous activity levels than did patients treated with early surgical stabilization.

Strength and functional performance recovery after anterior cruciate ligament reconstruction in preadolescent athletes

Background:

In the skeletally immature population, the incidence of anterior cruciate ligament (ACL) injuries and ACL reconstructions appears to be increasing. Differences in surgical techniques, physiology, and emotional maturity may alter the rehabilitation progression and impact the outcomes when compared with adults. Reports of objective strength recovery and performance-based outcome measures after pediatric ACL reconstruction (ACLR) are limited.

Study Design:

Retrospective case series.

Level of Evidence:

Level 4.

Methods:

All patients that underwent all-epiphyseal ACLR from January 2008 to August 2010 were identified. Isokinetic peak quadriceps/hamstring torque values and functional performance measures in unilateral hopping tasks were extracted and compared with the noninjured limb. A limb symmetry index (LSI) of ≥90% was considered satisfactory.

Results:

Complete data were available for 16 patients (mean age, 12.28 years; range, 8.51-14.88 years). By a mean 7 months (range, 3.02-12.56 years) postoperatively, only 9 of 16 (56%) were able to achieve a satisfactory LSI for quadriceps strength. For hamstring strength, 15 of 16 (94%) were able to achieve satisfactory LSI. By a mean of 12 months (range, 5.39-24.39 months) postoperatively, only 6 of 16 subjects (38%) were able to achieve satisfactory performance on all functional hop tests. At a mean 15.42 months (range, 8.58-24.39 months) postsurgery, only 4 of 16 (25%) subjects were able to achieve an LSI of ≥90% on all testing parameters.

Conclusion:

For some pediatric patients, significant strength and functional deficits may be present at greater than 1 year after ACLR. This population may require more prolonged rehabilitation programs to allow for adequate recovery of strength and function because of unique characteristics of normal growth and development.

Anterior cruciate ligament injuries in adolescents with open physis: effect of recurrent injury and surgical delay on meniscal and cartilage injuries

BACKGROUND

Treatment choices for skeletally immature patients sustaining anterior cruciate ligament (ACL) injuries have been controversial. The main dilemma is whether surgical treatment should be provided before patients reach skeletal maturity or whether nonoperative treatment should be provided until the physis has closed. Surgical reconstruction risks physeal damage, while delaying surgery may increase menisci and cartilage damage.

PURPOSE

To identify patients at the onset of ACL injury and follow them longitudinally to surgery or final follow-up to describe differences between nonoperative and operative patients and to analyze the effect of delayed reconstruction.

STUDY DESIGN

Cohort study; Level of evidence, 3.

METHODS

A retrospective review of patients enrolled at a large integrated health care system (IHS) between January 1, 2005, and December 31, 2008, was performed. The study sample included all females ≤12 years old and males ≤14 years old who were evaluated with an ACL injury. The incidence of ACL injuries in each age group was calculated using the number of covered lives by the IHS system per age category as the denominator. Each patient was longitudinally followed using an electronic health record that captures all patient encounters. Every encounter was reviewed for symptoms associated with the index knee, and encounters were considered significant if new-onset pain or swelling was reported. Patients were instructed to restrict their activities while awaiting skeletal maturity to undergo reconstruction by not participating in activities that included any cutting or pivoting movements that would risk injury to the knee. Cartilage and meniscal injuries were recorded for patients who underwent reconstruction.

RESULTS

A total of 71 patients were identified during the study period (66 males, 4 females). At the completion of this study, 47 (66.2%) patients had undergone ACL reconstruction, and 24 (33.8%) were being treated nonoperatively. While there were no significant associations between time to surgery and meniscal or cartilage injury, there was a positive association between the number of significant encounters and the likelihood of a combined cartilage and meniscal injury (P = .01).

CONCLUSION

This is the first study to measure the incidence of ACL injuries in a skeletally immature population. For patients undergoing ACL reconstruction, an increased number of significant encounters was statistically significantly associated with combined meniscal and cartilage injuries, while increased time from injury to surgery was not significantly associated with additional injuries. In addition, one-third of the patients continued nonoperative treatment without symptoms that warranted surgical interventions during the follow-up period.

Anterior cruciate ligament injuries: diagnosis, treatment, and prevention

The number of anterior cruciate ligament (ACL) injuries reported in athletes younger than 18 years has increased over the past 2 decades. Reasons for the increasing ACL injury rate include the growing number of children and adolescents participating in organized sports, intensive sports training at an earlier age, and greater rate of diagnosis because of increased awareness and greater use of advanced medical imaging. ACL injury rates are low in young children and increase sharply during puberty, especially for girls, who have higher rates of noncontact ACL injuries than boys do in similar sports. Intrinsic risk factors for ACL injury include higher BMI, subtalar joint overpronation, generalized ligamentous laxity, and decreased neuromuscular control of knee motion. ACL injuries often require surgery and/or many months of rehabilitation and substantial time lost from school and sports participation. Unfortunately, regardless of treatment, athletes with ACL injuries are up to 10 times more likely to develop degenerative arthritis of the knee. Safe and effective surgical techniques for children and adolescents continue to evolve. Neuromuscular training can reduce risk of ACL injury in adolescent girls. This report outlines the current state of knowledge on epidemiology, diagnosis, treatment, and prevention of ACL injuries in children and adolescents.

Mid-term results of transphyseal anterior cruciate ligament reconstruction in children and adolescents

BACKGROUND

Optimal therapy for anterior cruciate ligament (ACL) rupture in the paediatric population still provokes controversy. Although conservative and operative treatments are both applied, operative therapy is slightly favored. Among available surgical techniques are physeal-sparing reconstruction and transphyseal graft fixation. The aim of this study was to present our mid-term results after transphyseal ACL reconstruction.

METHODS

Fifteen young patients (mean age=12.8±2.6, range=6.2-15.8 years, Tanner stage=2-4) with open physis and traumatic anterior cruciate rupture who had undergone transphyseal ACL reconstruction with unilateral quadriceps tendon graft were prospectively analyzed. All children were submitted to radiological evaluation to determine the presence of clearly open growth plates in both the distal femur and proximal tibia. Postoperatively, all patients were treated according to a standardized rehabilitation protocol and evaluated by radiographic analysis and the Lysholm-Gillquist and IKDC 2000 scores. Their health-related quality of life was measured using the SF-12 PCS (physical component summary) and MCS (mental component summary) questionnaires.

RESULTS

Mean postoperative follow-up was 4.1 years. Mean Lysholm-Gillquist score was 94.0. Thirteen of the 15 knees were considered nearly normal on the IKDC 2000 score. The mean SF-12 questionnaire score was 54.0±4.8 for SF-12 PCS and 59.1±3.7 for SF-12 MCS. No reruptures were observed. Radiological analysis detected one knee with valgus deformity. All patients had a normal gait pattern without restrictions.

CONCLUSION

Transphyseal reconstruction of the anterior cruciate ligament shows satisfactory mid-term results in the immature patient.

Current concepts of the management of anterior cruciate ligament injuries in children

Recent reports have suggested an increase in the number of anterior cruciate ligament (ACL) injuries in children, although their true incidence is unknown. The prognosis of the ACL-deficient knee in young active individuals is poor because of secondary meniscal tears, persistent instability and early-onset osteoarthritis. The aim of surgical reconstruction is to provide stability while avoiding physeal injury. Techniques of reconstruction include transphyseal, extraphyseal or partial physeal sparing procedures. In this paper we review the management of ACL tears in skeletally immature patients.

Pediatric ACL injuries: evaluation and management

The anterior cruciate ligament (ACL) is a stabilizing structure to both anterior translation of the tibia with respect to the femur as well as rotation of the knee joint. Children and adolescents are susceptible to these injuries, and there are some who believe the incidence of ACL injuries in this population is increasing due to year round single sport participation. Pediatric ACL injuries are typically seen in several forms: tibial avulsion fractures, partial ACL tears, and full thickness ligament tears. There were and still are some who feel that ACL injuries should be treated non-operatively in the pediatric and adolescent population; however, recent literature refutes this notion. Several factors must be considered during pediatric and adolescent ACL reconstruction, each of which will be examined in this manuscript, including: status of the physis, reconstruction technique, and graft source.

Dynamic evaluation of pivot-shift kinematics in physeal-sparing pediatric anterior cruciate ligament reconstruction techniques

BACKGROUND

Conventional transphyseal anterior cruciate ligament (ACL) reconstruction techniques in skeletally immature patients have been questioned because of potential physeal injuries. Consequently, multiple alternative reconstruction options have been described to restore stability while sparing the physes in the skeletally immature patient.

HYPOTHESIS

All pediatric reconstruction techniques will restore knee stability to intact levels, and the knee stability index (KSI) will discriminate stability patterns between reconstruction techniques.

STUDY DESIGN

Controlled laboratory study.

METHODS

A novel mechanical pivot-shift device (MPSD) that consistently applies dynamic loads to cadaveric knees was used to study the effect of different physeal-sparing ACL reconstruction techniques on knee stability. Six adult cadaveric fresh-frozen knees were used. All knees were tested with 3 physeal-sparing reconstruction techniques: all epiphyseal (AE), transtibial over the top (TT), and iliotibial band (ITB). The MPSD was used to consistently perform a simulated pivot-shift maneuver. Tibial anterior displacement (AD), internal rotation (IR), posterior translational velocity (PTV), and external rotational velocity (ERV) were recorded using an Optotrak navigation system. The KSI (score range, 0-100; 0 = intact knee) was quantified using a regression analysis of AD, IR, PTV, and ERV. Repeated-measures analysis of variance and logistic regression were used for comparison of kinematics and derivation of KSI coefficients, respectively.

RESULTS

ACL deficiency resulted in an increase of 20% to 115% in all primary stability measures tested compared with the ACL-intact state. All reconstructions resulted in a decrease in ADmax and IRmax as well as PTVmax and ERVmax to within intact ranges, indicating that all reconstructions do improve stability compared with the ACL-deficient state. The ITB reconstruction overconstrained AD and IR by 38% and 52%, respectively. The mean (±SD) KSI for the ACL-deficient state was 61.7 ± 22.2 (range, 47-100), while the ITB reconstruction had a mean KSI of 0.82 ± 24.0 (range, -24 to 35), the TT reconstruction had a mean KSI of 13.3 ± 8.9 (range, 0.3-23), and the AE reconstruction had a mean KSI of -4.0 ± 15.2 (range, -24 to 14). The KSI was not significantly different between reconstructions, and all were significantly lower than the ACL-deficient state (P < .0001).

CONCLUSION

Although all reconstruction techniques tested were able to partially stabilize an ACL-deficient knee, the AE reconstruction was most effective in restoring native knee kinematics under dynamic loading conditions that mimic the pivot-shift test.

CLINICAL RELEVANCE

This study provides orthopaedic surgeons with objective dynamic rotational data on the ability of physeal-sparing ACL reconstructions to better determine the ideal technique for ACL construction in skeletally immature patients.

Prevention of ACL injury, part I: injury characteristics, risk factors, and loading mechanism

The anterior cruciate ligament (ACL) injury is one of the most common injuries in sports. ACL injuries are not only costly from financial and health services consumption standpoints, but also can have devastating consequences on patients' activity levels and quality of life. Tremendous efforts have been made over the past two decades toward the goal of preventing ACL injuries. A substantial number of studies have been performed to determine the characteristics of ACL injury events, identify risk factors for ACL injury, and develop prevention strategies. The purpose of this review was to objectively summarize the current literature regarding the characteristics of ACL injury, ACL loading mechanisms, and risk factors for injury to provide a comprehensive understanding of the current state of research and how our current level of knowledge may inform clinical practice in this area.

The current evidence for treatment of ACL injuries in children is low: a systematic review

BACKGROUND

There is no consensus on the management of anterior cruciate ligament (ACL) injuries in skeletally immature children, and the methodological quality of published studies is questionable. The transphyseal reconstructions, physeal-sparing reconstructions, and nonoperative treatment algorithms that are advocated have little support in the literature. The purpose of this study was to systematically review the methodological quality of the literature on the management of ACL injuries in skeletally immature children.

METHODS

We performed a literature search with use of PubMed to identify prospective or retrospective studies whose primary aim was to assess the outcome after operative or nonoperative treatment of ACL injuries in skeletally immature children. To be included in the analysis, a study had to have a mean duration of follow-up of at least two years and a minimum of ten children in the study had to be verified to be skeletally immature. The methodological quality of the included studies was evaluated with use of the Coleman Methodology Score.

RESULTS

No randomized controlled trials, two prospective cohort studies, and twenty-nine retrospective studies met the inclusion criteria. The Coleman Methodology Score averaged 44.7 ± 9.2 out of 100 (range, 28 to 62). The methodological deficiencies were most evident with regard to the number of included children, the study design, and the description of rehabilitation protocols, outcome criteria, and outcome assessments.

CONCLUSIONS

Caution is necessary when interpreting the results of studies on the treatment of ACL injuries in skeletally immature children because of widespread methodological deficiencies. There is a need for appropriately sized prospective studies and detailed descriptions of rehabilitation programs.

Management of anterior cruciate ligament injuries in skeletally immature individuals

Anterior cruciate ligament (ACL) injuries in skeletally immature individuals remain a challenge for the child, the parents, orthopaedic surgeons, and physical therapists. The main challenges are the potential risk of recurrent instability, secondary injuries following nonoperative treatment, and the risks involved with surgical treatment due to the vulnerability of the epiphyseal growth plates. We first present the physiological background for considerations that must be made when advising on treatment alternatives for skeletally immature individuals after ACL injury. The implications of continuous musculoskeletal development for treatment decisions are emphasized. No randomized controlled trials have been performed to investigate outcomes of different treatment algorithms. There is no consensus in the literature on clinical treatment decision criteria for whether a skeletally immature child should undergo transphyseal ACL reconstruction, physeal sparing ACL reconstruction, or nonoperative treatment. Additionally, well-described rehabilitation programs designed for either nonoperative treatment or postoperative rehabilitation have not been published. Based on the currently available evidence, we propose a treatment algorithm for the management of ACL injuries in skeletally immature individuals. Finally, we suggest directions for future prospective studies, which should include development of valid and reliable outcome measures and specific rehabilitation programs.

Pediatric anterior cruciate ligament reconstruction

An increasing number of anterior cruciate ligament (ACL) injuries are seen in children now than in the past due to increased sports participation. The natural history of ACL deficient knees in active individuals, particularly in children is poor. Surgical management of ACL deficiency in children is complex due to the potential risk of injury to the physis and growth disturbance. Delaying ACL reconstruction until maturity is possible but risks instability episodes and intra-articular damage. Surgical options include physeal-sparing, partial transphyseal and complete transphyseal procedures. This article reviews the management of ACL injured skeletally immature patients including the functional outcome and complications of contemporary surgical techniques.

Reduced platelet concentration does not harm PRP effectiveness for ACL repair in a porcine in vivo model

Enhanced primary repair of the ACL using a collagen scaffold loaded with platelets has been shown to improve the functional healing of suture repair in animal models. In this study, our objectives were to determine if lowering the platelet concentration would reduce the structural properties of the repaired ACL and increase postoperative knee laxity. Eight Yucatan mini-pigs underwent bilateral suture repair. In one knee, the repair was augmented with a collagen scaffold saturated with platelet-rich plasma (PRP) containing five times the systemic baseline of platelets (5×) while the contralateral knee had a collagen scaffold saturated with PRP containing three times the systemic baseline of platelets (3×). After 13 weeks of healing, knee joint laxity and the structural properties of the ACL were measured. The 3× platelet concentration resulted in a 24.1% decrease in cellular density of the repair tissue (p < 0.05), but did not significantly decrease the structural properties [3× vs. 5×: 362 N vs. 291 N (p = 0.242) and 70 N/mm vs. 53 N/mm (p = 0.189) for the yield load and linear stiffness, respectively]. The 3× platelet concentration also did not significantly change the mean anteroposterior knee laxity at 30° and 90° of flexion [5× vs. 3×: 3.5 mm vs. 5.1 mm (p = 0.140), and 6.1 mm vs. 6.3 mm (p = 0.764)] but did result in a lower AP laxity at 60° [5× vs. 3×: 8.6 mm vs. 7.3 mm (p = 0.012)]. The decrease in platelet concentration from 5× to 3× to enhance suture repair of the ACL did not significantly harm the mechanical outcomes in this animal model.

Physeal-sparing reconstruction of anterior cruciate ligament tears in children: results of 57 cases using patellar tendon

This study evaluated the results of a physeal-sparing technique of intra-articular anterior cruciate ligament (ACL) reconstruction in skeletally immature patients, with particular reference to growth disturbance. Between 1992 and 2007, 57 children with a mean age of 12.2 years (6.8 to 14.5) underwent ACL reconstruction using the same technique. At a mean of 5.5 years (2 to 14) after surgery, 56 patients underwent clinical and radiological evaluation. At that time, 49 patients (87.5%) had reached bony maturity and 53 (95%) achieved A or B according to the IKDC 2000 classification. Four patients had stopped participation in sports because of knee symptoms, and three patients (5.4%) had a subsequent recurrent ACL injury. There was no clinical or radiological evidence of growth disturbance after a mean growth in stature of 20.0 cm (3 to 38). This study demonstrates that ACL reconstruction sparing the physes in children is a safe technique protecting against meniscal tears and giving better results than reconstruction in adults, without causing significant growth disturbance.

Treating anterior cruciate ligament tears in skeletally immature patients

PURPOSE

To systematically review the current evidence for conservative and surgical treatment of anterior cruciate ligament (ACL) tears in skeletally immature patients.

METHODS

A systematic search of PubMed, CINAHL, EMBASE, CCTR, and CDSR was performed for surgical and/or conservative treatment of complete ACL tears in immature individuals. Studies with less than six months of follow-up were excluded. Study quality was assessed and data were collected on clinical outcome, growth disturbance, and secondary joint damage.

RESULTS

We identified 48 studies meeting the inclusion criteria. Conservative treatment was found to result in poor clinical outcomes and a high incidence of secondary defects, including meniscal and cartilage injury. Surgical treatment had only very weak evidence for growth disturbance, yet strong evidence of good postoperative stability and function. No specific surgical treatment showed clearly superior outcomes, yet the studies using physeal-sparing techniques had no reported growth disturbances at all.

CONCLUSIONS

The current best evidence suggests that surgical stabilization should be considered the preferred treatment in immature patients with complete ACL tears. While physeal-sparing techniques are not associated with a risk of growth disturbance, transphyseal reconstruction is an alternative with a beneficial safety profile and a minimal risk of growth disturbance. Conservative treatment commonly leads to meniscal damage and cartilage destruction and should be considered a last resort.

LEVEL OF EVIDENCE

Level IV, systematic review of Level II, III, and IV studies.

Intraarticular stabilization following anterior cruciate ligament injury in children and adolescents

PURPOSE

Significant controversy exists regarding the potential harm to the growth plate following reconstruction of the anterior cruciate ligament in skeletally immature patients. This study was performed to evaluate the results of a transepiphyseal replacement of the anterior cruciate ligament in skeletally immature patients.

METHODS

Ninety-four skeletally immature patients (56 male and 38 female) with median age 13.7 years (range, 11.6-15.9 years) who underwent arthroscopic transphyseal reconstruction of anterior cruciate ligament with four-strand medial hamstring autograft between 1999 and 2006 were reviewed. All patients had been followed up until skeletal maturity was confirmed.

RESULTS

The average follow-up was 38 months (range 24-60 months). Neither leg length discrepancy nor angular deformities were noted on radiological or clinical measurement. Two patients had radiographic evidence of mild arthrosis at final follow-up. New traumatic injuries occurred in 4 patients, in whom surgical revision was performed. Ligament laxity testing with a KT 1000/2000 arthrometer showed no significant difference between the normal and the operated legs. At follow-up, the median Lysholm score was 89 (range 77-100), and the median Tegner activity score was increased from 3 to 6. The International Knee Documentation Committee score was A in 79 patients (84%) and B in 6 patients (6%) and C in 9 patients (9%). Of the 94 patients, 73 (78%) returned to their similar preoperative sport activities and 90% returned to their preoperative level of daily activities.

CONCLUSIONS

ACL reconstruction with medial hamstring autograft via transepiphyseal drilling and grafting yielded satisfactory clinical results with no growth defects in skeletally immature patient. The preliminary results of this series demonstrated that this surgical technique can be performed in prepubescent patients with efficacy and safety.

LEVEL OF EVIDENCE

IV.

Good surgical outcome of transphyseal ACL reconstruction in skeletally immature patients using four-strand hamstring graft

PURPOSE

Our purpose was to evaluate the clinical and radiological outcome at maturity of an « adult-like » transphyseal anterior cruciate ligament (ACL) reconstruction performed in skeletally immature patients using four-strand hamstring graft.

METHODS

The records of all skeletally immature patients who underwent transphyseal ACL reconstruction between 2004 and 2006 at our institution were reviewed. Inclusion criteria were age less than 16 years and radiographic evidence of open physes. Thirty-eight children and prepubescents were identified. All underwent postoperative clinical evaluation with International Knee Documentation Committee scores and long leg radiographs. Each patient was followed up until skeletal maturity was confirmed.

RESULTS

Twenty-eight patients were scored A, four B, and five D according to IKDC. At last follow-up, there was no radiographic evidence of malalignment in any of the patients. Five underwent a reoperation. Three patients suffered traumatic graft disruption and two from post-operative knee instability.

CONCLUSION

Early operative treatment by means of the quadruple hamstring free graft appears to be a safe and relevant procedure for ACL reconstruction even in skeletally immature patients.

The potential for primary repair of the ACL

The objective of this work is to assess the feasibility of successfully repairing the torn anterior cruciate ligament (ACL). Two major motivators for developing a new treatment for ACL injuries are the recently reported high rates of osteoarthritis, after conventional ACL reconstruction, and the problem of how to safely treat skeletally immature patients. A key factor in developing such a technique was the identification of the main inhibitor of intrinsic ACL healing-the lack of clot formation between the 2 torn ends of the ligament. A bioactive and biocompatible scaffold, which could be placed in the wound site to enhance cellular proliferation and biosynthesis, was developed. This biomaterial has shown promising functional outcomes in several large animal models of primary repair of partial and complete ACL transection over 4 to 14 weeks, suggesting potential for a successful, future clinical application.

Fibrin concentration affects ACL fibroblast proliferation and collagen synthesis

Fibrin is a frequently used biomaterial in surgery and tissue engineering. While it has been shown that fibrin supports cellular proliferation and biosynthesis, there is a scarcity of studies focusing on the effects of fibrin concentration. The objective of this study is to assess the effect of fibrin concentrations around the physiological concentration of 3mg/ml on the behavior of ligament fibroblasts. Fibroblasts were obtained from the anterior cruciate ligaments of four pigs and seeded throughout fibrin gels of either 1, 3, or 6 mg/ml fibrin. The gels were collected at 2, 6, and 10 days for measurement of DNA and collagen content. We found that both DNA and collagen content increased significantly over time in gels made with all concentrations of fibrin. However, the increases were significantly lower in gels made with the higher concentrations of fibrin (3 and 6 mg/ml). Microscopic assessment of FITC-labeled gels showed a decrease in pore size at high fibrin concentrations, which might be a reason for the observed effect on bioactivity. To enhance cell behavior and thus clinical results fibrin applications should build on physiologic or sub-physiologic concentrations, and those with higher concentrations, such as currently available sealants, should be used cautiously.

Transphyseal reconstruction of the anterior cruciate ligament in prepubescent athletes

ACL reconstruction in adolescents undergoing or being beyond the final growth spurt can be performed as in adults without major concern of growth disturbance. Whereas for the young athlete with wide-open physis a lot of controversy still exists about the technical aspect of the procedure to minimise the risk of growth disturbance. Between 10/1997 and 10/2002 31 children graded Tanner stage 1 or 2 (median age 11 years) with an intraligamental rupture of the anterior cruciate ligament were enrolled. Seventeen patients with coexisting intraarticular damage (meniscus, osteochondral flake) underwent transphsyeal reconstruction of the ACL with the use of an autogenous semitendinosus tendon graft, whereas 14 patients without coexisting pathologies received a nonoperative regime. Growth disturbance, functional and radiographic outcome could be evaluated in 28 patients at a median of 70 months after initial treatment. No patient had clinical or radiological evidence for varus/valgus malalignment or leg length discrepancy. The mean of subsequent body growth within the study population was 20.3 cm. Patients operated on revealed significant (P < 0.05) better clinical (KT-1000 side-to-side difference, pivot shift) and functional results according to the IKDC (median, 95 vs. 87), Lysholm (median, 93 vs. 84) and the Tegner score. More than half of the conservatively treated patients (58%) had subsequent surgery due to persistent instability. Transphyseal reconstruction of intraligamental ACL ruptures with an autologous ST graft yielded superior clinical results if compared to a nonoperative treatment in immature prepubescent patients being Tanner stage 1 and 2.