Physeal-sparing technique for femoral tunnel drilling in pediatric anterior cruciate ligament reconstruction using a posteromedial portal

Assessment of Skeletal Maturity and Postoperative Growth Disturbance After Anterior Cruciate Ligament Reconstruction in Skeletally Immature Patients: A Systematic Review

BACKGROUND

Growth disturbance is an uncommon but potentially serious complication after anterior cruciate ligament (ACL) reconstruction in skeletally immature patients.

PURPOSE

To describe how the pediatric ACL literature has assessed preoperative skeletal maturity and the amount of growth remaining and to comprehensively review the incidence, reporting, and monitoring of postoperative growth disturbance.

STUDY DESIGN

Systematic review; Level of evidence, 4.

METHODS

This review included studies reporting original research of clinical outcomes of skeletally immature patients after ACL reconstruction. Patient characteristics, surgical techniques, preoperative assessments of skeletal maturity or growth remaining, and postoperative assessments of growth disturbances were extracted.

RESULTS

A total of 100 studies met inclusion criteria. All studies reported chronological age, and 28 studies (28%) assessed skeletal age. A total of 44 studies (44%) used Tanner staging, and 12 studies (12%) obtained standing hip-to-ankle radiographs preoperatively. In total, 42 patients (2.1%) demonstrated a leg length discrepancy (LLD) >10 mm postoperatively, including 9 patients (0.5%) with LLD >20 mm; furthermore, 11 patients (0.6%) with LLD underwent growth modulation. Shortening was the most common deformity overall, but overgrowth was reported more frequently in patients who had undergone all-epiphyseal techniques. Most LLDs involved the femur (83%). A total of 26 patients (1.3%) demonstrated a postoperative angular deformity ≥5°, and 9 of these patients underwent growth modulation. The most common deformities were femoral valgus (41%), tibial recurvatum (33%), and tibial varus (22%). Although standing hip-to-ankle radiographs were the most common radiographic assessment of growth disturbance, most studies inadequately reported the clinical and radiographic methods of assessment for growth disturbance. Additionally, only 35% of studies explicitly followed patients to skeletal maturity.

CONCLUSION

This systematic review described significant variability in the reporting and monitoring of growth-related complications after ACL reconstruction in skeletally immature patients. The incidence of LLD and angular deformity appeared to be low, but the quality of research was not comprehensive enough for accurate assessment.

REGISTRATION

CRD42019136059 (PROSPERO).

Physeal-sparing posteromedial portal approach reduced distance between guide pin and neurovascular structures

PURPOSE

To compare a femoral physeal sparing anterior cruciate ligament (ACL) reconstruction technique utilizing a posteromedial portal to traditional transphyseal techniques with regards to anatomic tunnel positioning and proximity to important neurovascular structures.

METHODS

Eight cadaveric knees were obtained for the study. Femoral tunnel guide pins were placed utilizing four different techniques: accessory anterior medial portal, posteromedial portal, trans-tibial, and figure-4 methods. The knees were then dissected and the following measurements taken: distance of each pin to the saphenous and peroneal nerve, popliteus tendon, neurovascular bundle, femoral ACL footprint and articular cartilage, and the angle of the guide pin entering the lateral femoral condyle. Fluoroscopic imaging was taken to determine the disruption of the physeal scar.

RESULTS

Posteromedial portal guide pin was significantly closer to the neurovascular bundle, popliteal tendon and saphenous nerve when compared to the other 3 techniques, but was further from the peroneal nerve. It also had the smallest distance from the anatomic footprint of the ACL, and the largest angle to the lateral femoral condyle. The posteromedial portal guide pin had similar distance from the articular cartilage as the accessory anterior medial portal and figure-4 guide pin, with the trans-tibial guide pin being the farthest. The posteromedial portal guide pin failed to disrupt the physeal scar in all specimens, while the other three techniques consistently violated the physeal scar.

CONCLUSION

The posteromedial portal technique offers an appropriate method for anatomic ACL reconstruction while protecting the distal femoral physis from injury. Care needs to be taken with this technique as it comes in closer proximity to some of the important neurovascular structures. This study indicates that posteromedial portal technique is a less technically challenging approach for physeal-sparing ACL repair with special attention required for the protection of neurovascular bundle from potential injury.

Primary Anterior Cruciate Ligament Repair With Hyaluronic Scaffold and Autogenous Bone Marrow Aspirate Augmentation in Adolescents With Open Physes

It is well known that the anterior cruciate ligament (ACL) is the main stabilizer to the anterior tibial translation in the knee. The current gold standard of treatment for such lesions is ACL reconstruction. However, there are notable disadvantages to ACL reconstruction that include loss of proprioception, donor site morbidity, incomplete return to high-demand sports, and the inability to restore normal kinematics of the knee joint. Additionally, in adolescents who have open physes, there is a risk of potential iatrogenic growth plate injury. Tibial-sided soft-tissue avulsion is a rare subtype of ACL injuries. This Technical Note presents a method for primary anatomic ACL repair with a bioabsorbable scaffold and bone marrow concentrate augmentation for an acute distal ACL injury. Our technique is an alternative to reconstruction as it allows the preservation of the native insertion site and has the potential to reduce the risk of posttraumatic osteoarthritis.

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

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.

Regenerative Medicine Approaches for the Treatment of Pediatric Physeal Injuries

The physis, or growth plate, is a cartilaginous region at the end of children's long bones that serves as the primary center for longitudinal growth and characterizes the immature skeleton. Musculoskeletal injury, including fracture, infection, malignancy, or iatrogenic damage, has risk of physeal damage. Physeal injuries account for 30% of pediatric fractures and may result in impaired bone growth. Once damaged, cartilage tissue within the physis is often replaced by unwanted bony tissue, forming a "bony bar" that can lead to complications such as complete growth arrest, angular or rotational deformities, and altered joint mechanics. Children with a bony bar occupying <50% of the physis usually undergo bony bar resection and insertion of an interpositional material, such as a fat graft, to prevent recurrence and allow the surrounding uninjured physeal tissue to restore longitudinal bone growth. Clinical success for this procedure is <35% and often the bony bar and associated growth impairments return. Children who are not candidates for bony bar resection due to a physeal bar occupying >50% of their physis undergo corrective osteotomy or bone lengthening procedures. These approaches are complex and have variable success rates. As such, there is a critical need for regenerative approaches to not only prevent initial bony bar formation but also regenerate healthy physeal cartilage following injury. This review describes physeal anatomy, mechanisms of physeal injury, and current treatment options with associated limitations. Furthermore, we provide an overview of the current research using cell-based therapies, growth factors, and biomaterials in the different animal models of injury along with strategic directions for modulating intrinsic injury pathways to inhibit bony bar formation and/or promote physeal tissue formation. Pediatric physeal injuries constitute a unique niche within regenerative medicine for which there is a critical need for research to decrease child morbidity related to this injurious process.

Proximity of Lateral Critical Structures to the All-Epiphyseal Outside-In Femoral Tunnels in Pediatric Anterior Cruciate Ligament Reconstruction

PURPOSE

To describe the proximity of the lateral critical structures (peroneal nerve [PN], popliteus tendon [PT], lateral collateral ligament [LCL], and articular cartilage [AC]) to the femoral tunnel for outside-in all-epiphyseal anterior cruciate ligament (ACL) reconstruction in reference to knee flexion angle.

METHODS

All-epiphyseal ACL reconstructions were performed in 12 human cadaveric knees using arthroscopy and outside-in drilling for anatomic femoral tunnel placement that was ensured by identifying the center of the total ACL footprint. Fluoroscopy was used to confirm tunnel position and reconstructions were performed with quadrupled semitendinosus and gracilis autograft with Xtendobutton (Smith & Nephew, Andover, MA) fixation on the femoral side. After reconstruction, the lateral side of the knee was dissected and the LCL, PT, distal and posterior AC, and the PN were identified. The distances of these structures from the center of the exiting femoral tunnel were then measured using a digital caliper at 0°, 30°, 60°, 90°, and 120° of knee flexion. Any gross damage to these structures caused by the femoral drilling was also noted. Data were compiled and the mean and standard deviations (SD) of the distances from the pin to the structures of interest were calculated. The normality of the data at each flexion angle was assessed using Shapiro-Wilk tests (P > .05), and the relationship between flexion angle and average distance was evaluated using repeated measures analysis of variance (P < .05). Any significant relationships were then evaluated using paired t-tests (P < .05) with a Benjamini-Hochberg adjustment for each possible pair of flexion angles. Averages, SD, and P values are reported. A post hoc power analysis was performed.

RESULTS

The violation of the LCL was noted in 3 specimens and that of the PT in 1 specimen as a result of femoral tunnel drilling at flexion angles ranging from 90° to 120°. The distance between the PT and the femoral tunnel also decreased significantly (P < .001) with knee flexion with average distances to the center of 8.07 mm at 0°, 7.75 mm at 30°, 6.33 mm at 60°, 4.12 mm at 90°, and 1.89 mm at 120°. The mean ± SD for distances from the femoral tunnel to the center of the PT at 0° was 8.07 ± 7.15, at 30° 7.75 ± 6.66, at 60° 6.33 ± 6.79, at 90° 4.12 ± 5.71, and at 120° 1.89 ± 5.56. As the knee was progressively flexed, the distance between the LCL and the femoral tunnel decreased significantly (P < .001) with an average distance of 6.52 mm at 0°, 6.26 mm at 30°, 4.23 mm at 60°, 2.38 mm at 90°, and 0.4 mm at 120°. The mean ± SD for distances from the femoral tunnel to the center of the LCL at 0° was 6.52 ± 5.93, at 30° 6.26 ± 7.32, at 60° 4.23 ± 7.82, 90° 2.38 ± 7.31, and at 120° 0.4 ± 7.01. The PN was remote from the femoral tunnel at all flexion angles with a mean distance of 42.83 to 59.22 mm. The PN to guide pin distance increased significantly with progressive knee flexion (P < .001). The AC was not damaged in all specimens.

CONCLUSIONS

The LCL and PT are at significant risk during percutaneous femoral drilling for all-epiphyseal anatomic ACL reconstruction using an outside-in technique. This risk was maximized at 120° flexion and minimized in full extension. These findings suggest that the optimal position for femoral drilling in all-epiphyseal ACL reconstruction is full or near-full extension of the knee that can be accomplished by placing the knee in 30° of flexion (after using fluoroscopic guidance to pass the guide pin past the lateral critical structures) to visualize the footprint of the ACL.

CLINICAL RELEVANCE

Information garnered from this study may help clinicians better understand the risk to the lateral critical structures when an outside-in femoral tunnel is not drilled in the appropriate degree of knee flexion.

Temperature Change When Drilling Near the Distal Femoral Physis in a Skeletally Immature Ovine Model

BACKGROUND

The possibility of physeal injury during anterior cruciate ligament reconstruction in the pediatric population is a concern. The purpose of this study was to determine whether drilling at or near the physis could cause a temperature increase that could trigger chondrolysis.

METHODS

Skeletally immature cadaveric lamb distal femurs were used for this study and randomly placed in 1 of 6 groups (n=10 in each group). We examined the 8 and 10 mm Flipcutter at a distance of 0.5 mm from the physis and an 8 and 10 mm acorn-tipped reamer at a distance of 0.5 and 3.0 mm from the physis. During drilling, temperature change at the distal femoral physis was continuously measured until the temperature decreased to the original value.

RESULTS

An interreamer comparison yielded a significant difference when drilling 0.5 mm from the physis (P=0.001). Pair-wise Mann-Whitney post hoc tests were performed to further evaluate the differences among the groups. The 8 mm FlipCutter had a significantly higher maximum temperature (39.8±1.4°C) compared with the 10 mm FlipCutter (38.0±0.6°C, P=0.001), 8 mm acorn-tipped reamer (38.1±0.9°C, P=0.007), and 10 mm acorn-tipped reamer (37.5±0.3°C, P<0.001).

CONCLUSIONS

The risk of thermal-induced injury to the physis is low with an all epiphyseal drilling technique, when a traditional acorn-tipped reamer over a guidepin is utilized, even if the drilling occurs very close to the physis. In addition, the risk of drilling with a FlipCutter is low, but may be greater than a traditional reamer.

CLINICAL RELEVANCE

Thermal-induced necrosis is a realistic concern, due to the characteristics of the distal femoral physis, and the propensity for this physis to respond poorly to injury. Our study supports that drilling near the physis can be done safely, although smaller reamers and nontraditional designs may generate higher heat.

LEVEL OF EVIDENCE

Level I-basic science.

All-Inside, All-Epiphyseal Anterior Cruciate Ligament Reconstruction in Skeletally Immature Athletes: Return to Sport, Incidence of Second Surgery, and 2-Year Clinical Outcomes

BACKGROUND

Anterior cruciate ligament (ACL) injuries in skeletally immature athletes are increasing.

PURPOSE

To evaluate the 2-year clinical outcomes of all-inside, all-epiphyseal ACL reconstruction in skeletally immature athletes with 3 to 6 years of remaining growth, with a focus on return to sport and the incidence of second surgery.

STUDY DESIGN

Case series; Level of evidence, 4.

METHODS

Twenty-three skeletally immature athletes were prospectively evaluated after all-epiphyseal ACL reconstruction utilizing a hamstring autograft. The athletes' age, sex, sport, mechanism of injury, radiographs, and magnetic resonance imaging (MRI) findings were noted. The evaluation included a physical examination, KT-1000 arthrometer measurements, isokinetic testing, and validated outcome scores. Standing radiographs and spoiled gradient recalled echo MRI scans were obtained at 6, 12, and 24 months postoperatively. A quality of movement assessment and return-to-sport performance analysis were also performed.

RESULTS

Of the 23 athletes, 6 were female (mean age, 11.3 years), and 17 were male (mean age, 12.6 years). At a minimum follow-up of 2 years (range, 24-45 months), the mean International Knee Documentation Committee score was 94.6 ± 4.9, the mean Lysholm score was 97.9 ± 4.0, the mean Marx activity rating scale score was 13.4 ± 3.6, and the mean Hospital for Special Surgery Pediatric Functional Activity Brief Scale score was 23.9 ± 7.0. Lachman and pivot-shift test results were negative in all patients. The mean side-to-side difference on the KT-1000 arthrometer was 0.9 ± 0.5 mm and less tight on the operated side. No significant growth disturbances were noted; however, 6 athletes had a leg-length discrepancy of more than 5 mm (range, 6-18 mm). Two patients had overgrowth in the femur of more than 15 mm (16 mm and 18 mm). Two athletes (8.7%) required second surgery. The mean time to return to unrestricted activity was 13.5 months (range, 8-22 months).

CONCLUSION

The all-inside, all-epiphyseal ACL reconstruction technique using a hamstring autograft demonstrates excellent subjective and objective clinical outcomes in skeletally immature athletes without physeal arrest.

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.

Anterior Cruciate Ligament Reconstruction Using the Transphyseal Technique in Prepubescent Athletes: Midterm, Prospective Evaluation of Results

PURPOSE

To evaluate the efficacy, results, and complications of transphyseal technique of anterior cruciate ligament (ACL) reconstruction in prepubertal patients and to assess a possible influence of children's growth on the outcome.

METHODS

Between 2005 and 2009, 22 (16 boys and 6 girls) prepubescent patients, Tanner stage 1 and 2, underwent ACL reconstruction and the follow-up 6, 12, and 24 months after surgery and after growth plate closure. The average age of the girls was 11.2 years, and of the boys, 12.3 years. The average follow-up period was 77.2 months. Clinical outcome was evaluated by Lysholm, Tegner, and International Knee Documentation Committee (IKDC) objective and subjective knee scores. Standard radiograms were performed for potential axial growing disturbance.

RESULTS

The average follow-up period was 77.2 months (range, 54 to 102 months), and IKDC subjective scores changed from 58 (range, 44 to 69) before surgery to 87 (range, 86 to 87; P = .00) at 6 months, 93 (range, 88 to 97; P = .00) at 12 months, and 95 (range, 92 to -98; P = .5) at final examination. Lysholm score increased from 58 (range, 53 to 64) before surgery to 89 (range, 85 to 92; P = .00) at 6 months and 96 (range, 94 to 100; P = .00) at 12 months, 24 months (P = .9), and final examination (P = .8). Before injury, all patients were graded 7 on the Tegner scale. Nineteen athletes reached at least grade 7 and returned to the level of activity a mean of 9 months after the surgery. No patient had deformity or growth disturbances observed clinically.

CONCLUSIONS

Arthroscopic-assisted transphyseal ACL reconstruction in prepubescent patient is a promising technique, provided that all technical details are respected. It gives excellent subjective and objective knee scores and provides a very good function of the knee joint in the midterm period with no or only minor effect on the leg length. The rate of growth after surgery did not influence the results.

LEVEL OF EVIDENCE

Level IV, therapeutic case series.