Dynamic Magnetic Resonance Imaging Protocol: An Effective and Useful Tool to Assess Discoid Lateral Meniscus Instability in Children.

OBJECTIVES: One of the most common symptoms in cases of discoid lateral meniscus (DLM) in children is a "snapping" knee. The clock in extension, followed by a pop in flexion, perceived by the clinician, reflects the meniscal displacement caused by the peripheral meniscocapsular detachment. Standard magnetic resonance imaging (MRI) results in a 40% false-negative rate for detecting this instability. The hypothesis was that a dynamic MRI protocol could reduce the false negative rate and improve the efficiency of the MRI in detecting the direction of instability. METHODS: Eight DLM knees (8 patients) with snapping knees (grade 2 of Lyon's classification) were included in this monocentric prospective preliminary study in a referral center of pediatric orthopaedic surgery. Every patient underwent a dynamic MRI protocol with both T2-Fat-Sat sagittal and coronal slices, performed "after the clock" and again "after the pop" in a knee with standard 20 degrees of flexion during acquisition. All the MRI data were correlated with an arthroscopic description of the peripheral tear of the DLM according to Ahn's classification to assess for diagnostic accuracy. RESULTS: The standard MRI protocol resulted in a false-negative rate of 50% for detecting the direction of instability. The dynamic MRI protocol allowed the identification of, and classification of the meniscal instability, meniscal shift, and meniscocapsular tear in 8 of 8 patients (0% false-negative rate), perfectly correlated with arthroscopic findings. CONCLUSION: This preliminary series, although short, allowed us to understand all the types of movements and lesions associated with the child's discoid meniscus. The detailed case analysis showed a strong benefit of such a protocol for planning the surgical suture procedure. The functionality and reliability of the dynamic MRI protocol is a good and method relatively simple method which does not require specific equipment, minimizing any additional cost compared with standard MRI. LEVEL OF EVIDENCE: Level IV.

Reconstruction with antibiotic loaded single-side gore-tex "Tartine" methyl-methacrylate cementoplasty for pediatric chest wall reconstruction: A 10-case series.

INTRODUCTION: Chest wall reconstruction in children after large resection of tumors may be performed with rigid or soft materials. Cementoplasty is commonly used with the "Sandwich" method i.e. gore-tex meshes surrounding both faces of the cement. HYPOTHESIS: Is antibiotic loaded single-side gore-tex "Tartine" methyl-methacrylate cementoplasty an interesting alternative to the double-side "sandwich" method for chest wall reconstruction? MATERIAL AND METHODS: Consecutive patients who were treated from 2011 to 2023 in our hospital were included. RESULTS: Among the ten children treated with a median 5.6 years follow-up, there were no surgical complications related to the reconstruction, loss of function, infections, post operative complications (versus 22.7% in meta-analysis encompassing the 50 rigid reconstructions reported worldwide) nor scoliosis (versus 25%). Three patients have an asymmetric chest wall appearance. DISCUSSION: "Tartine" cementoplasty is a simple, low-cost technique for pediatric chest wall reconstruction. It is well tolerated and checks key demands for chest wall reconstructions. LEVEL OF EVIDENCE: IV; retrospective case series.

Absorbable Sutures Repair Without Meniscopexy, Results in Superior Outcomes for Discoid Lateral Meniscus With Meniscocapsular Anterior Detachment in Children.

BACKGROUND: Despite the fact that meniscocapsular anterior detachment is the most common location of instability in children with a Discoid Lateral Meniscus (DLM), there is a lack of consensus about the type of repair that should be utilized for stabilization. The aim of this study was to determine the best fixation method for anterior detachment of DLM in children. Our hypothesis was that excessive rigidity with fixation would restrict meniscal mobility and increase the rate of failure or prevent full knee flexion. METHODS: This study was a retrospective single-center study consisting of 51 consecutive knees (45 children) with menico-capsular anterior detachment that underwent stabilization and minimal saucerization of the meniscus between 2007 and 2018. We aimed to compare the need for revision surgery and knee flexion between the different types of fixations utilized; namely we compared meniscopexy using anchors on the tibia (n=30) with outside-in arthroscopic soft tissue fixation (n=21), and absorbable (n=18) and nonabsorbable sutures (n=33) were compared. RESULTS: The mean age at surgery was 10.4 years (3 to 17) with a mean follow-up of 52 months (18 to 148). The group of knees treated with absorbable sutures had a significantly better rate of full knee flexion (15/18) compared with the nonabsorbable group (17/33) ( P =0.03). Despite the absence of significance ( P =007), there was a lower rate of revision surgery due to suture failure in the soft tissue fixation group (0 revision operations) compared with the meniscopexy group (5 revision operations). CONCLUSIONS: For anterior meniscocapsular detachment of DLM, it is recommended to perform soft tissue fixation with absorbable sutures, as this technique resulted in better knee flexion and a lower rate of revision surgery when compared with meniscopexy and nonabsorbable suture fixation. LEVEL OF EVIDENCE: Level III-retrospective case studies.

Asymmetric Deficit of Knee Flexion: An Occasional Symptom of Discoid Lateral Meniscus in Children.

PURPOSE: A knee flexion deficit can be the unique symptom and sign of discoid lateral meniscus (DLM) in children. The aim of this study was to investigate the accuracy of this clinical sign. The hypothesis was that deficit of knee flexion was associated with anterior rim disinsertion and posteriorly fixed DLM. METHODS: A retrospective, single-center study was conducted in a larger series of 114 operated knees for symptomatic DLM from 2007 to 2018. A focus was done on 9 knees with a deficit of knee flexion without snapping. History and clinical examination with grading of instability, preoperative magnetic resonance imaging, and arthroscopic findings were studied. RESULTS: Among 35 knees with DLM grade 3 of instability, 26 had an isolated extension deficit. Nine knees in 5 boys and 4 girls with a mean age of 9 years (range 6 to 12) had a flexion deficit. It was the only symptom of DLM in 6, and it was associated to extension deficit in 3. In the history, 8 knees were grade 2 (snapping knee) before evolving toward a flexion deficit. All had a complete DLM with posterocentral (n=7) or central (n=2) shift at magnetic resonance imaging analysis. All had DLM with posterior shift fixed during arthroscopic evaluation. Moreover, looking at the entire series, 1 knee was a false negative and had a full flexion despite a posterior and fixed DLM during arthroscopic evaluation. The sensitivity of asymmetrical knee flexion to predict posterior fixed DLM was 90%. CONCLUSIONS: An asymmetric deficit in knee flexion is highly suggestive of DLM with anterior detachment and fixed posterior meniscal shift (specificity and positive predictive value of 100%). Given this could be the only clinical sign of DLM, specific attention therefore must be paid in the assessment of knee flexion by measuring the distance between heel and bottom on both sides, especially in a knee without snapping currently but with a history of snapping (grade 3). LEVEL OF EVIDENCE: Level III.

Arthroscopic Suture-Saucerization of Discoid Meniscus Allows Volume Conservation but Does Not Fully Restore Coverage.

Purpose: The purpose of this study was to quantify the effect of meniscoplasty suture-saucerization on volume and surface coverage of lateral discoid menisci. Methods: This retrospective study included all consecutive 10 patients treated between 2014 and 2019 who had magnetic resonance imaging before and after surgery and 15 controls. The MITK 3M3 semiautomatic software was used to segment the meniscus and cartilage before and after surgery to measure the percentage of meniscus coverage on the tibial cartilage. Results are compared to control patients without knee pathology matched on sex and age with Student t test. Results: Discoid meniscus surface and volume before surgery were respectively 597 mm2 (range, 550-887 mm2) and 2,822 mm³ (1,571-3,407 mm³), representing 74.5% (56%-89%) of the tibial cartilage surface. After surgery, it decreased to 422 mm2 (229-569 mm2) and 1,235 mm³ (680-1,738 mm³), leading to 45.7% (22.5%-68.6%) coverage. In the control group, median surface was 457 mm2 (314-641 mm2), volume was 1,321 mm3 (641-2,240 mm3), and tibial coverage was 55% (41%-77%). Altogether, meniscus volume after surgery was similar to normal, while coverage was significantly lower than controls (P = .04). Conclusions: Meniscoplasty suture-saucerization procedure may allow meniscus sparing and restauration of a similar to normal meniscus volume. Meniscus surface and coverage are diminished compared to controls. Both surface and volume normalization is usually not achievable without decreasing the thickness of the rather thick discoid meniscus. Clinical Relevance: Both surface and volume normalization is usually not achievable without decreasing the thickness of thick discoid menisci.

Discoid lateral meniscus instability in children: part II.: Repair first to minimise the saucerisation.

PURPOSE: Despite an improved understanding of discoid lateral meniscus (DLM), the treatment of symptomatic discoid lateral meniscus remains controversial. METHODS: The aim of this retrospective, single-centred, consecutive-case study was to evaluate the clinical outcome of 60 DLM treated arthroscopically by the "meniscoplasty or saucerisation-suture" technique in children and adolescents [median (range) age 11 (4-17) years], and to investigate surgical failures. The instability was assessed before any saucerisation. The hypotheses were that: (i) the management of instability with suture first was effective and that (ii) a combined classification with clinical and MRI data had a prognostic value. RESULTS: In 57 knees (95%), the DLM was unstable, and a suture fixation was performed. After a median follow-up of 41.5 months, the median (range) IKDC score was improved from 55 (10-70) preoperatively to 90 (37.5-100) postoperatively. The median (range) Lysholm score at last follow-up was 93.5 (45-100). The procedure was effective in 49 knees (81.6%) after a single procedure. Eleven patients had a failure with a new meniscal tear after a median (range) delay of 42 months (24-60) after the initial procedure. The patterns of discoid lateral meniscus instability were not found to have a prognostic value for surgical failure since they mainly occurred after sport-related injuries. All the patients with initial repair failures but one achieved a good clinical outcome after revision repair without any further meniscectomy. CONCLUSION: In contrast to adult knees, symptomatic discoid lateral meniscus is rarely stable in children (5%). Meniscal repair is effective to preserve the meniscus tissue, but revision repair became necessary in 18% of the cases and was finally successful. Level of evidence Level III.

Growth progression of anterior cruciate ligament bone grafts in a pediatric population: magnetic resonance imaging analysis.

BACKGROUND: In children, the incidence of anterior cruciate ligament (ACL) ruptures and reconstructions has significantly risen. Unfortunately, re-rupture rates following surgery are substantially higher in children than adults. Previous research suggests that smaller graft diameters are predictive of re-rupture. OBJECTIVE: This study aimed to investigate the growth progression of the ACL bone graft, specifically in terms of width and length, within the intra-articular portion and tunnels, using successive magnetic resonance imaging (MRI) scans. The hypothesis was that the ACL grafts would undergo thinning during growth. MATERIALS AND METHODS: The cohort comprised 100 patients who underwent ACL reconstruction. Among them, 37 patients with significant residual growth were selected for analysis. Of these, 4 patients experienced graft rupture, 5 had "over-the-top" techniques, 12 had missing MRI scans and 5 were lost to follow-up. Each included patient underwent two MRI scans; the analyses of which were conducted in a double-masked manner. RESULTS: A total of 13 knees (and patients) were analyzed, with a mean ± SD (range) delay of residual growth between the two MRI scans of 3.3 + / - 1.4 (1.2-5.2) years. The graft exhibited elongation, thinning and eventual integration with the surrounding bone in the tunnels. Within the intra-articular portion, the mean [95% CI] increase in graft size between the two MRI scans was 30.8% in length and 14.8% in width. The width/length ratio in the intra-articular part was 20.4% on the first MRI and 20.8% on the second MRI. Since this difference in the ratio (+ 0.4%) was not statistically significant (P=0.425), our results indicate that the grafts remained stable in terms of proportions without thinning or thickening. Therefore, the initial hypothesis was validated for the tunnel portion but not the intra-articular portion of the grafts. CONCLUSION: In children with open physes, ACL grafts demonstrate smooth growth progression in all dimensions. However, this finding does not fully explain the high rate of re-rupture observed in children. Further research is needed to elucidate the underlying factors contributing to re-rupture in this population.

Epiphyseal-sparing biological reconstruction of bone sarcoma in children: Focus on articular function and growth.

INTRODUCTION: Epiphyseal preservation surgery and biological reconstruction after resection of metaphyseal bone sarcoma in children is a surgical challenge which can only be justified if future joint function is maintained. HYPOTHESIS: The main hypothesis of this work was that long-term function was maintained. The secondary hypotheses were that local control of the disease and growth restoration were achieved, at the cost of an acceptable number of complications. MATERIAL AND METHOD: This was a retrospective study of 14 children with a median age of 8 years [2-14] at the time of surgery. The tumors (Ewing's sarcoma or osteosarcoma) were mostly situated at the knee (n=9) and hip (n=3). The reconstruction used an induced membrane (n=7) or an allograft (n=7). We studied joint function, mechanisms contributing to loss of growth, surgical complications and survival at the last follow-up. RESULTS: At the median follow-up of 76 months [24-130], 9 out of 14 patients required revision for non-union, and 4 of them required a second revision. At the last follow-up, 82% of the length had been restored, due to 3 bone lengthenings and 7 contralateral epiphysiodeses. Preserved joint function was excellent with an average modified MSTS score of 28.3/30 [24-30]. No local recurrence was reported. DISCUSSION: Our experience of epiphyseal preservation allows local control of the disease and very good function but at the cost of a cumbersome surgical program (12 out of 14 patients were reoperated on, with an average of 1.2 interventions per patient). The main difficulty is the growth management, most often by complex programs of alternating bone lengthening and shortening. LEVEL OF EVIDENCE: IV, retrospective study.

Isolated MPFL reconstruction with soft tissue femoral fixation technique in 54 skeletally immature patients: Clinical outcomes at 2 years follow-up. A French multicenter retrospective study.

BACKGROUND: Medial patello-femoral ligament (MPFL) reconstruction is one of the therapeutic options to treat patellofemoral instability. Classically, a à la carte treatment of skeletal and ligament abnormalities is described. This option is difficult to achieve in children because bony procedures can damage the femoral and/or tibial growth plate. The objective was to evaluate a strategy for isolated reconstruction of the MPFL in the treatment of objective patellar instabilities in children, in a large cohort. The return to sport, knee function and pain or discomfort were studied as secondary endpoints. METHODS: This French multicenter retrospective study included 54 pediatric patients with objective patellofemoral instability. Patients were included if they had presented at least 2 episodes of objective patella dislocation. A Deie-like technique with gracilis tendon graft, soft tissue femoral fixation and patellar bone tunnels for patellar fixation was used. Recurrence of dislocation was studied as the primary endpoint, and the recurrence rate was compared with the literature. A comparison of functional scores (Kujala, Lille femoro-patellar instability score or LFPI Score and Tegner activity score) and NRS between pre- and postoperative was studied as a secondary objective. RESULTS: A recurrence of femoro-patellar instability was observed for five patients within 2 years follow up (9%). A significant improvement of the Kujala, LFPI score, Tegner and NRS scores was observed (p<0.001). CONCLUSION: Isolated reconstruction of the MPFL presents a risk of recurrence of 9% at 2years follow-up. This technique significantly improves the functional scores of the knee. This modified Deie technique provides good clinical and functional results, allowing return to sports with an acceptable risk of recurrence of patellar dislocation, similar to those observed in the literature. Isolated MPFL reconstruction as a first-line treatment appears to be a reliable and effective technique in terms of recurrence of dislocation and functional scores. It allows early recovery and rehabilitation and has lower morbidity than procedures requiring bone gestures. LEVEL OF EVIDENCE: III, retrospective comparative study.

Identification of a novel translocation producing an in-frame fusion of TAF15 and ETV4 in a case of extraosseous Ewing sarcoma revealed in the prenatal period.

Ewing sarcoma (ES) is a highly malignant round cell sarcoma, characterized by gene fusion involving FET (FUS, EWSR1, TAF15) and ETS family genes, respectively. The involvement of the EWSR1 gene has been reported in approximately 90% of cases of ES, with the EWSR1::FLI1 fusion being the most frequent. We report the case of a newborn with a localized soft tissue paravertebral neoplasm diagnosed prenatally. Histopathology and immunophenotype were consistent with a CD99 + , NKX2.2 + undifferentiated round cell sarcoma (URSC); whole-exome RNA-sequencing demonstrated an undescribed in-frame TAF15::ETV4 fusion transcript, while consensus clustering analysis showed high transcriptomic proximity to the ES group. Given clinical context, high tumor chemosensitivity to ES conventional drugs, morphological characteristics, nature of the fusion partners involved, and high transcriptomic proximity to bona fide ESs, this case may represent a new genetic variant of ES.

Locally aggressive rarely metastazing tumors and low-grade sarcoma in children, adolescents and young adults: The benefits of a national network.

INTRODUCTION: Complete surgical resection constitutes the mainstay of treatment for locally aggressive, rarely metastazing tumor and low-grade soft tissue sarcomas (LAS). Local relapse is the most common tumor event, especially in the presence of positive margins (R1 margins). The aims of this study are to assess the impact of the national network on patient care and to evaluate the role of immediate re-excision in children, adolescents and young adults with incompletely resected LAS. METHODS: National retrospective multicenter study of all young patients (≤25 years) included in the Sarcoma "ConticaBase" treated for LAS between 2005 and 2017 for whom pathology/biology review was available via the national NETSARC + network. RESULTS: A total of 96 patients were identified (median age: 16 years). Tumors were localized in 99% of cases (1 N+ tumor). With a median follow-up of 4.7 years (range: 0.1-11.9), eight local relapses and two distant metastases were observed. No patient died. Overall 5-year event-free survival (EFS) was 90.4% [95%CI, 84.3-97]. Five year EFS for R1 patients (n = 51) with (n = 24) and without (n = 27) immediate re-excision was 90.5% [95%CI, 78.8-100.0] and 80.3% [95%CI, 64.7-99.9], respectively (p = 0.34). The 37 patients directly treated in a reference center more commonly had a diagnostic biopsy (78% vs. 21%; p < 0.001), more complete surgery (R0: 65% vs. 14%; p < 0.001) and less commonly underwent re-excision (16% vs. 54%; p < 0.001). CONCLUSIONS: This large series indicates that LAS are rare in young patients and have a favorable prognosis. Immediate management in reference centers is associated with better standard of care. The main tumor events are local relapses.

Misdiagnosed cartilaginous PCL avulsion in young children.

Posterior Cruciate Ligaments injuries are rare in children and usually due to bony avulsion fractures or midsubstance tears. This study focused on cartilaginous avulsions initially misdiagnosed despite of MRI assessment. Two 6-year-old boys had cartilaginous avulsion fracture injury at the femoral attachment of the PCL. One had associated medial meniscal lesion and was reinserted. The other conducted to non-union. MRI second lecture reveals an original description with nail-biting sign on cartilage surface of anterior notch, and a close PCL angle without anterior tibial translation. No bone bruise was associated. Similarly, to ACL cartilaginous tibial avulsions, PCL cartilaginous femoral avulsions are underdiagnosed. When knee hemarthrosis occurs under the age of nine, clinician and radiologist should be aware that cartilaginous avulsion of ACL and PCL also could be the main pattern of lesion.

Pleuropneumonectomy as Salvage Therapy in Children Suffering from Primary or Metastatic Sarcomas with Pleural Localizations.

Pediatric sarcoma patients with pleuropulmonary lesions have a dismal prognosis because the impossibility to obtain local control. The aim of this study was to determine if pleuropneumonectomy (PP) could be a therapeutic option. We retrospectively reviewed nine patients who underwent salvage PP for pleuropulmonary localization of primary localized sarcoma or metastatic recurrence. Surgery and complications were analyzed, pulmonary function tests were conducted, and quality of life was determined with EORTC-QLQ-C30 questionnaire. At the time of PP age was between 9-17 years. Underlying disease included metastatic osteosarcoma (n = 5), Ewing sarcoma (two metastatic, one primary), and one primary undifferentiated sarcoma. Early complications occurred in three patients. Mean postoperative hospitalization stay was 14.5 days. Pulmonary function test showed 19-66% reduction of total lung capacity which led to mild exercise intolerance but did not affect daily life. Four patients died of multi-metastatic relapse <14 months after PP, one patient had a local recurrence, and four patients are in complete remission between 1.5 and 12 years after PP. In conclusion, in this small patient group treated with a pleuropneumonectomy for primary or metastatic lesions, outcome is variable; however, this extended surgical technique was generally quite well tolerated. Postoperative lung function seems well preserved, and it seems to lead to at least an extension of life with good quality and therefor can be considered as salvage therapy.

Axial patellar engagement index and patellar tilt after medial patello-femoral ligament reconstruction in children and adolescents.

BACKGROUND: The medial patello-femoral ligament (MPFL) is a major patellar stabiliser whose reconstruction in adults involves graft fixation within a femoral tunnel. In skeletally immature patients, in contrast, the graft is fixed to the soft tissues to allow normal growth. The primary objective of this prospective study was to perform computed tomography (CT) and magnetic resonance imaging (MRI) assessments of medium-term correction of patellar tilt and of the axial patellar engagement index (AEI) after a paediatric variant of MPFL reconstruction in skeletally immature patients. HYPOTHESIS: MPFL reconstruction, performed alone or combined with other procedures in skeletally immature patients, decreases patellar tilt and improves the AEI. MATERIAL AND METHODS: Eighteen children and adolescents with a median age of 14.6 years (range, 8-17 years) who underwent MPFL reconstruction on 20 knees were included in this prospective observational study. A double-strand gracilis tendon graft passed through the medial collateral ligament was used. MPFL reconstruction was performed alone in 13 knees and was combined with lateral retinaculum release, tibial tuberosity translation, and/or trochleoplasty in 7 knees. Patellar tilt and AEI values determined on preoperative and post-operative imaging studies with the quadriceps relaxed and contracted were compared. A physical examination was also performed. RESULTS: From baseline to last follow-up after a mean of 43 months (range, 24-63 months), patellar tilt decreased from 20° preoperatively to 9° with the quadriceps relaxed and from 33° to 15.4° with the quadriceps contracted. The AEI increased from 0.78 at baseline to 0.93 at last follow-up. No dislocation or subluxation recurrences were recorded during follow-up. DISCUSSION: The patellar tilt and AEI improvements seen after paediatric MPFL reconstruction confirm the study hypothesis. This is the first prospective study of patellar position in the axial plane as assessed by CT and MRI after paediatric MPFL reconstruction. In everyday clinical practice, 3D assessments of patellar tilt and the AEI should be performed to evaluate correction of the abnormalities. LEVEL OF EVIDENCE: II, non-randomised prospective observational study.

MRI assessment of growth disturbances after ACL reconstruction in children with open growth plates-Prospective multicenter study of 100 patients.

INTRODUCTION: We were interested in the consequences of anterior cruciate ligament (ACL) reconstruction on the growth plates and the impact on growth in children with open growth plates. The primary objective was related to growth disturbances with the null hypothesis being that ACL reconstruction in open growth plates does not cause any. The secondary objective related to the presence of physis lesions on MRI, with the null hypothesis being that ACL reconstruction in open growth plates does not induce any. MATERIAL AND METHODS: In the context of a 2017 SFA symposium on ACL reconstruction with open growth plates, we conducted a prospective multicenter study with 2 years' follow-up. The study enrolled 100 patients; 71 were available for analysis. Four reconstruction techniques were used: semitendinosus-gracilis (STG), short graft (SG), quadriceps tendon (QT) and fascia lata (FL). MRI was used to look for growth disturbances as evidenced by deviation of the Harris lines or modification of the physis and diaphysis angles. Physis lesions were determined on MRI based on the presence of physeal bone bridges (PBB). RESULTS: No growth disturbances were found. However, PBBs were found in 14 patients (20%). At the femur, the relative risk (RR) was higher when a STG graft was used (RR=2.1) and the tunnel diameter was≥9mm (RR=1.7). Epiphyseal fixation had a higher risk than transphyseal fixation (RR=1.6 vs. 1.2). At the tibia, the RR was higher when a QT graft was used (RR=3.6), when screw fixation was performed (RR=3.7) or when the graft did not fill the tunnel sufficiently (RR=1.5). DISCUSSION: The absence of growth disturbances after 2 years' follow-up validates the possibility of ACL reconstruction with open growth plates, including with transphyseal techniques. The presence of small growth plate lesions such as bone bridges means that precautions should be taken with respect to tunnel trajectory, tunnel diameter, graft and tunnel diameter matching and graft fixation. LEVEL OF EVIDENCE: III, prospective cohort study.

MRI study of the ligamentization of ACL grafts in children with open growth plates.

INTRODUCTION: There is little published information on the ligamentization of pediatric anterior cruciate ligament (ACL) grafts. The aims of our study were to compare the MRI appearance of ACL grafts performed in a population with open growth plates to normal ACLs in adolescents and to determine whether the MRI signal in the grafts at 6 months could predict a retear. We hypothesized that ligamentization was a slow, gradual process. MATERIAL AND METHODS: This was a prospective multicenter study of 100 ACL grafts (quadriceps tendon, hamstring tendon, fascia lata) in children 7 to 16 years of age. Of these, 65 intact grafts underwent one or more MRI examinations between 6 months and 2 years postoperative. MRI images were also analyzed in 7 patients who suffered a retear and in the intact ACL of 20 adolescents (15 to 18 years of age). The other 28 patients did not undergo an MRI during the postoperative phase. For each MRI, the signal-to-noise quotient (SNQ) was calculated in three different areas in the ACL (proximal, middle, distal) along with the Howell intra-articular and intra-tibial grades from I to IV. The Mantel-Haenszel Chi-square, Wilcoxon signed-rank test and Student's t-test were used to compare groups. The Lin concordance correlation coefficients were calculated for inter-rater consistency. RESULTS: There was a difference in the SNQ between the three zones of a normal ACL. Most were Howell grade III (55% Howell III, 25% Howell II and 20% Howell I). For intact grafts, the SNQ improved significantly between 6 and 12 months and between 6 and 24 months. There was no difference in the SNQ between the three zones independent of the postoperative time point. The intra-articular Howell grade improved significantly between 6 and 24 months and between 12 and 24 months. The intra-tibial Howell grade improved significantly between 12 and 24 months. There were no significant differences between patients with intact grafts and those who suffered a retear. There were no differences between the various types of grafts used. CONCLUSION: Normal ACLs in adolescents have inhomogeneous SNQ and Howell grades. The SNQ and Howell grades in ACL grafts are more homogeneous and continue to improve out to 2 years, but do not reach that of a normal ACL. The signal and appearance of an ACL graft and normal ACL are very different, and the MRI signal at 6 months postoperative is not predictive of retear. LEVEL OF EVIDENCE: III, prospective study.

Return to sport and re-tears after anterior cruciate ligament reconstruction in children and adolescents.

BACKGROUND: The primary objective of this study was to determine the time to and level of return to sports after anterior cruciate ligament (ACL) reconstruction in children and adolescents. The secondary objectives were to evaluate the risk of early ACL re-tear after return to sports and the risk of ACL tear in the contralateral knee. HYPOTHESIS: The time to return to sports in young patients is considerably longer than in adults. METHODS: A prospective multicentre study was conducted at 12 centres specialised in knee ligament surgery, in children and adolescents younger than 18 years, between 1 January 2015 and 31 October 2015. The patients were divided into a paediatric group with open physes and a skeletally mature group with closed physes. We recorded the time to return to sport, the type of sport resumed, and the occurrence of early re-tears on the same side. A poor outcome was defined as a re-tear or an objective IKDC score of C or D. A contralateral ACL tear was not considered a poor outcome. RESULTS: Of 278 included patients, 100 had open physes and 178 closed physes. In the open physes group, return to running occurred after 10.4±4.7 months, return to pivoting/contact sport training after 13.1±3.9 months, and return to pivoting/contact sport competitions after 13.8±3.8 months. Of the 100 patients, 80% returned to the same sport and 63.5% to pivoting/contact sport competitions. Re-tears occurred in 9% of patients, after 11.8±4.1 months, and contralateral tears in 6% of patients, after 17.2±4.4 months. In all, 19.4% of patients had a poor outcome, including 10.4% with an IKDC score of C or D and 9% with re-tears. In the group with closed physes, return to running occurred after 8.8±5.1 months, return to pivoting/contact sport training after 11.7±4.7 months, and return to pivoting/contact sport competitions after 12.3±4.2 months. Of the 178 patients, 76.9% returned to the same sport and 55.6% to pivoting/contact sport competitions. The re-tear rate was only 2.8% and the contralateral tear rate 5%. In all, 14.7% of patients had poor outcome, including 11.9% with an IKDC score of C or D and 2.8% with re-tears. No risk factors for re-tears were identified; the quadruple-bundle semitendinosus technique showed a non-significant association with re-tears. CONCLUSION: In young children, the return to sport time after ACL reconstruction is considerably longer than 1 year and the return to competitions occurs later and is more difficult. The results of this study indicate that reservations are in order when informing the family about return to sports prospects after ACL reconstruction. The return to pivoting/contact sport competitions should not be allowed until 14 months after surgery in young skeletally immature patients, and the risk of re-injury is high within the first 2 years. LEVEL OF EVIDENCE: IV, retrospective study.

Conservative management of anterior cruciate ligament injury in paediatric population: About 53 patients.

INTRODUCTION: The last symposium held by the French Arthroscopy Society was on anterior cruciate ligament (ACL) reconstruction on children. The first aim of this study was to analyse the tolerance of conservative management of ACL rupture in children. We also tried to find predictive factors of ACL reconstruction. MATERIAL AND METHODS: We conducted an observational, retrospective study in an academic department of paediatric orthopaedic surgery. All patients under the age of eighteen, who were treated conservatively for an acute intra-ligamentous ACL rupture confirmed by magnetic resonance imaging (MRI) between 2007 and 2017, were included. Two groups were analysed: operated patients and conservative treatment. We also analysed population according Tanner stage. RESULTS: Fifty-three patients were included in this study. The median length of follow-up was 31.5 months [interquartile range (IQR): 22.3-49.3]. The median age at the last follow-up was 14.4 years [IQR: 12.6-15.5]. All patients were allowed to practice activities without restrictions, including pivoting sports. Tegner activity level scale remains identical before injury and at last follow-up (p: n.s.). Nineteen patients (36%) described knee instability at last follow-up. On the last MRI, 9 (17%) patients had meniscal tears but only one patient (2%) needed a menisectomy. Twenty-one patients (40%) underwent ACL reconstruction. The 4-years successful conservative treatment rate was 92% (95% CI: 85-98%). Clinical instability at first examination was the only significant predictive factors of bad tolerance of conservative management (p=0.047). DISCUSSION: Conservative management of ACL rupture in paediatric population is a valuable treatment which permits return to a normal life with sports activities without major increasing of meniscal tears. The rehabilitation protocol must restore full knee stability to permit a successful conservative treatment. We must study the impact of pubertal status on larger group. LEVEL OF EVIDENCE: IV, retrospective study.