Juvenile Osteochondritis Dissecans of the Knee: Does Magnetic Resonance Imaging Instability Correlate With the Need for Surgical Intervention?

Longitudinal 3T MRI T2 * mapping of Juvenile osteochondritis dissecans (JOCD) lesions differentiates operative from non-operative patients-Pilot study

Juvenile osteochondritis dissecans (JOCD) is an orthopedic joint disorder of children and adolescents that can lead to premature osteoarthritis. Thirteen patients (mean age: 12.3 years, 4 females), 15 JOCD-affected and five contralateral healthy knees, that had a baseline and a follow-up magnetic resonance imaging (MRI) (mean interval of 8.9 months) and were treated nonoperatively during this interval were included. Retrospectively, patients were assigned to operative or nonoperative groups based on their electronic medical records. Volumetric mean T2 * values were calculated within regions of interest (progeny lesion, interface, parent bone) and region matched control bone in healthy contralateral knees and condyles. The normalized percentage difference of T2 * between baseline and follow up MRI in nonoperative patients significantly increased in progeny lesion (-47.8%, p < 0.001), parent bone (-13.9%, p < 0.001), and interface (-32.3%, p = 0.011), whereas the differences in operative patients were nonsignificant and below 11%. In nonoperative patients, the progeny lesion (p < 0.001) and interface T2 * values (p = 0.012) were significantly higher than control bone T2 * at baseline, but not at follow-up (p = 0.219, p = 1.000, respectively). In operative patients, the progeny lesion and interface T2 * values remained significantly elevated compared to the control bone both at baseline (p < 0.001, p < 0.001) and follow-up (p < 0.001, p < 0.001), respectively. Clinical Significance: Longitudinal T2 * mapping differentiated nonhealing from healing JOCD lesions following initial nonoperative treatment, which may assist in prognosis and improve the ability of surgeons to make recommendations regarding operative versus nonoperative treatment.

An update on osteochondritis dissecans of the knee

Osteochondritis dissecans of the knee (OCD) is a multifactorial pathology in where repetitive microtrauma plays a central role in the etiopathogenesis. Knee MRI is indicated in young, active patients who have knee pain and/or effusion, to make an early diagnosis and decide about treatment, according essentially to the MRI stability signs. The choice of treatment should be also tailored, based on the patient's skeletal maturity, as well as the size and location of the lesion. Conservative treatment with restricting sports activities is the first line treatment and often sufficient to ensure healing in patients with open physes. Surgical treatment depends on the persistence of symptoms after 6 months of conservative treatment and/or based on the development of signs of instability of the lesion. Stable lesions with intact articular cartilage may be treated by drilling of the subchondral bone aiming to stimulate vascular ingrowth and subchondral bone healing. Every attempt should be made to retain the osteochondral fragment when possible. Instable lesions should be fixed or "replaced" with salvage procedures to prevent the onset of early osteoarthritis in this young population. Furthers studies are needed to improve the knowledge and optimizing non-operative and surgical treatment and to develop noninvasive diagnostic tools to predict with more accuracy the fragment's stability.

Evaluation of lesion and overlying articular cartilage in patients with juvenile osteochondritis dissecans of the knee using quantitative diffusion MRI

Current clinical MRI of patients with juvenile osteochondritis dissecans (JOCD) is limited by the low reproducibility of lesion instability evaluation and inability to predict which lesions will heal after nonoperative treatment and which will later require surgery. The aim of this study is to verify the ability of apparent diffusion coefficient (ADC) to detect differences in lesion microstructure between different JOCD stages, treatment groups, and healthy, unaffected contralateral knees. Pediatric patients with JOCD received quantitative diffusion MRI between January 2016 and September 2020 in this prospective research study. A disease stage (I-IV) and stability of each JOCD lesion was evaluated. ADCs were calculated in progeny lesion, interface, parent bone, cartilage overlying lesion, control bone, and control cartilage regions. ADC differences were evaluated using linear mixed models with Bonferroni correction. Evaluated were 30 patients (mean age, 13 years; 21 males), with 40 JOCD-affected and 12 healthy knees. Nine patients received surgical treatment after MRI. Negative Spearman rank correlations were found between ADCs and JOCD stage in the progeny lesion (ρ = -0.572; p < 0.001), interface (ρ = -0.324; p = 0.041), and parent bone (ρ = -0.610; p < 0.001), demonstrating the sensitivity of ADC to microstructural differences in lesions at different JOCD stages. We observed a significant increase in the interface ADCs (p = 0.007) between operative (mean [95% CI] = 1.79 [1.56-2.01] × 10^-3  mm² /s) and nonoperative group (1.27 [0.98-1.57] × 10^-3  mm² /s). Quantitative diffusion MRI detects microstructural differences in lesions at different stages of JOCD progression towards healing and reveals differences between patients assigned for operative versus nonoperative treatment.

Compositional evaluation of lesion and parent bone in patients with juvenile osteochondritis dissecans of the knee using T2 * mapping

Juvenile osteochondritis dissecans (JOCD) lesions contain cartilaginous, fibrous and osseous tissues which are difficult to distinguish with clinical, morphological magnetic resonance imaging (MRI). Quantitative T₂ * mapping has earlier been used to evaluate microstructure and composition of all aforementioned tissues as well as bone mineral density. However, the ability of T₂ * mapping to detect changes in tissue composition between different JOCD lesion regions, different disease stages, and between stable and unstable lesions has not been demonstrated. This study analyzed morphological and T₂ * MRI data from 25 patients (median age, 12.1 years) with 34 JOCD-affected and 13 healthy knees. Each lesion was assigned a stage reflecting the natural history of JOCD, with stages I and IV representing early and healed lesion, respectively. T₂ * values were evaluated within the progeny lesion, interface and parent bone of each lesion and in the control bone region. T₂ * was negatively correlated with JOCD stage in progeny lesion (ρ = -0.871; p < 0.001) and interface regions (ρ = -0.649; p < 0.001). Stage IV progeny showed significantly lower T₂ * than control bone (p = 0.028). T₂ * was significantly lower in parent bone than in control bone of patients with stable lesions (p = 0.009), but not in patients with unstable lesions (p = 0.14). Clinical significance: T₂ * mapping enables differentiation between different stages of JOCD and quantitative measurement of the ossification degree in progeny lesion and interface. The observed T₂ * decrease in healed and stable lesions may indicate increased bone density as a result of the active repair process. T₂ * mapping provides quantitative information about JOCD lesion composition.

The nonoperative treatment of osteochondritis dissecans of the knee

PURPOSE OF REVIEW

The purpose of this review is to update the reader on the controversial subject of osteochondritis dissecans (OCD) with a focus on nonoperative treatment indications, methods, and success rate.

RECENT FINDINGS

Work by an international multicenter study group ROCK (Research in OsteoChondritis of the Knee) will be reviewed including new classifications systems of healing, arthroscopy, radiographs, and MRI, along with new evidence on off-loading bracing compared to restricted weight bearing.

SUMMARY

The paucity of evidence behind OCD treatment of the knee can lead to confusion for doctors, patients, and parents. The present review will bring more clarity to the subject.

MRI evaluation of articular cartilage in patients with juvenile osteochondritis dissecans (JOCD) using T2∗ mapping at 3T

OBJECTIVE

Evaluate articular cartilage by magnetic resonance imaging (MRI) T2∗ mapping within the distal femur and proximal tibia in adolescents with juvenile osteochondritis dissecans (JOCD).

DESIGN

JOCD imaging studies acquired between August 2011 and February 2019 with clinical and T2∗ mapping MRI knee images were retrospectively collected and analyzed for 31 participants (9F/22M, 15.0 ± 3.8 years old) with JOCD lesions in the medial femoral condyle (MFC). In total, N = 32 knees with JOCD lesions and N = 14 control knees were assessed. Mean T2∗ values in four articular cartilage regions-of-interest (MFC, lateral femoral condyle (LFC), medial tibia (MT), and lateral tibia (LT)) and lesion volume were measured and analyzed using Wilcoxon-rank-sum tests and Spearman correlation coefficients (R).

RESULTS

Mean ± standard error T2∗ differences observed between the lesion-sided MFC and the LFC in JOCD-affected knees (28.5 ± 0.9 95% confidence interval [26.8, 30.3] vs 26.3 ± 0.7 [24.8, 27.7] ms, P = 0.088) and between the affected- and control-knee MFC (28.5 ± 0.9 [26.8, 30.3] vs 28.5 ± 0.6 [27.1, 29.9] ms, P = 0.719) were nonsignificant. T2∗ was significantly increased in the lesion-sided MT vs the LT for the JOCD-affected knees (21.5 ± 0.7 [20.1, 22.9] vs 18.0 ± 0.7 [16.5, 19.5] ms, P = 0.002), but this same difference was also observed between the MT and LT in control knees (21.0 ± 0.6 [19.7, 22.3] vs 18.1 ± 1.1 [15.8, 20.4] ms, P = 0.037). There was no significant T2∗ difference between the affected- and control-knee MT (21.5 ± 0.7 [20.1, 22.9] vs 21.0 ± 0.6 [19.7, 22.3] ms, P = 0.905). T2∗ within the lesion-sided MFC was not correlated with patient age (R = 0.20, P = 0.28) or lesion volume (R = 0.06, P = 0.75). T2∗ values were slightly increased near lesions in later-stage JOCD subjects but without statistical significance.

CONCLUSIONS

T2∗ relaxations times were not significantly different from control sites in the articular cartilage overlying JOCD lesions in the MFC or adjacent MT cartilage in early-stage JOCD.

Retroarticular Core Decompression with Biologic Augmentation for Juvenile Osteochondritis Dissecans of the Knee

Juvenile osteochondritis dissecans (OCD) of the knee is a rare condition of subchondral bone that has secondary effects on articular cartilage as the condition advances. Traditional treatment for early-stage OCD involves different types of drilling procedures that work to stimulate healthy bone formation via creeping substitution. This article describes a technique that involves a complete removal, or decompression of an early-stage OCD, while preserving the overlying articular cartilage that is augmented with bone grafting and bone marrow aspirate concentrate. This allows for quicker and more reliable healing of early-stage OCD and can minimize the chance for reoperation.