Magnetic Resonance Imaging of Osteochondritis Dissecans: Validation Study for the ICRS Classification System

Osteochondritis Dissecans of the Medial Femoral Condyle: MRI Findings of Instability

BACKGROUND: Osteochondritis dissecans (OCD) of the medial femoral condyle (MFC), a common cause of pediatric chronic knee pain, is often found to be stable at arthroscopy. OBJECTIVE: To investigate the performance of MRI for identifying instability of MFC OCD in children. METHODS: This retrospective study included 59 children (37 boys, 22 girls; mean age, 12.5±2.2 years) with 69 MFC OCD lesions, who underwent knee MRI from January 2016 to October 2023. Two radiologists independently reviewed examinations to determine regional findings (effusion, skeletal maturity, secondary physis visibility, progeny composition), as well as direct (osteochondral defect, intraarticular body, cartilage alteration, bone plate disruption, receded ossification front) and indirect (progeny-parent bone interface, radius of curvature, parent-bone low-signal intensity (SI) marginal rim, perilesional marrow edema) findings of instability; disagreements were resolved through consensus. Two investigators assessed an additional indirect finding, cyst(s), in consensus. Demographic characteristics, and lesion volume were collected. The reference standard for lesion stability was arthroscopy (n=52) or follow-up evaluation (based on symptoms and imaging findings) in patients managed conservatively (n=17). Stable and unstable lesions were compared. RESULTS: Forty-nine lesions were stable, and 20 were unstable. Sensitivity and specificity for instability, among features showing significant associations with instability, were 70.0% and 100.0% for skeletal maturity, 75.0% and 75.5% for osteochondral progeny composition, 100.0% and 85.7% for cartilage alteration, 85.0% and 81.6% for presence of progeny-parent bone interface, 30.0% and 100.0% for extensive interface, 90.0% and 34.7% for cyst(s), 45.0% and 91.8% for altered radius of curvature, 80.0% and 89.8% for parent-bone low-SI rim, and 50.0% and 81.6% for extensive perilesional marrow edema. In multivariable analysis, factors independently associated with instability included larger lesion volume and indirect signs (presence of interface, cyst(s), altered radius of curvature, parent-bone low-SI rim, and extensive perilesional marrow edema). Frequency of instability was 0.0%, 7.4%, 16.7%, 75.0%, 83.3%, and 100.0% for lesions with 0, 1, 2, 3, 4, and 5 indirect signs. CONCLUSION: Lesion instability was associated with an increasing number of indirect MRI signs. CLINICAL IMPACT: Assessment of lesion stability by MRI can help guide decisions between arthroscopy and conservative management for MFC OCD in children.

The efficacy and safety of leucine-enriched essential amino acids in knee osteoarthritis patients: A randomized controlled trial

BACKGROUND

Supplementation with leucine-enriched essential amino acids (LEAAs) has shown efficacy in the recovery of muscle injury and activation of muscle synthesis. Muscle function in knee osteoarthritis is a crucial factor for managing pain and preserving ambulatory function. However, the efficacy and safety of LEAAs supplementation in patients with knee osteoarthritis have not been evaluated.

METHODS

In this prospective analysis, we evaluated the efficacy and safety of supplementation with 12 g of LEAAs daily for 8 weeks in knee-symptomatic osteoarthritis patients. For assessing the efficacy, clinical pain, calf circumference, and disability were assessed using questionnaires (visual analog scale, Knee Society Score, and 36-item short form survey [SF-36]), laboratory analyses (total protein and albumin), and radiologic study (dual-energy X-ray absorptiometry [DEXA]) for muscle and bone density. To evaluate safety, generalized or localized protein allergic reactions, complete blood count, liver and kidney function, and serum glucose were measured.

RESULTS

Sixty-five participants, categorized into the experimental (n = 32) and control (n = 33) groups, were included in this 8-week trial from March 2022 to July 2022. A significantly higher efficacy was observed in the experimental group than in the control group, as indicated by muscle density in the DEXA scan (P = .001) and SF-36 (P < .001). The safety evaluation revealed no related generalized or local protein allergy. Hematological findings, serum glucose, and kidney and liver toxicity were not significantly different between the groups.

CONCLUSION

Supplementation with leucine-enriched proteins is safe and efficacious in the improvement of muscle density and quality of life.

Arthroscopic Repair of Acetabular Cartilage Delamination Using Chondral Nail Fixation in Patients With Femoroacetabular Impingement

Acetabular cartilage delamination is commonly seen in patients with femoroacetabular impingement (FAI), especially ones with the cam deformity. However, the definition and classification of acetabular cartilage injuries caused by FAI to guide clinical treatment remain controversial. Moreover, treatment of acetabular cartilage damage always causes a dilemma for surgeon during surgery. We believe a reliable repair of the acetabular cartilage delamination will lead to a better long-term outcome for patients with FAI. In this Technical Note, we introduce the chondral nail fixation under hip arthroscopy for treating acetabular cartilage delamination in patients with FAI. This technique contributes to eliminating intra-articular unstable factors, preserving native cartilage as much as possible, and restoring cartilage surface intact at best.

Osteochondritis Dissecans of the Knee Associated With Mechanical Overload

BACKGROUND

Osteochondritis dissecans (OCD) of the knee is a rare but potentially incapacitating disorder in which subchondral bone detaches, leading to an osteochondral fragment that can become unstable and progress into a loose body. The exact cause is unknown, although several biological and mechanical factors have been described.

PURPOSE

To provide insight into epidemiological data of a large cohort of patients affected by OCD of the knee and to identify potential factors contributing to the cause of this disorder.

STUDY DESIGN

Cross-sectional study; Level of evidence, 3.

METHODS

A total of 236 patients (259 knees) affected by OCD were included in our Knee Registry (2005-2022) and retrospectively analyzed. Patient characteristics were extracted from the medical records. Location and International Cartilage Regeneration & Joint Preservation Society grade (1-4) of OCD were assessed using magnetic resonance imaging. If available, a full-leg standing radiograph was used to assess alignment. Additionally, a statistical scoring system for instability risk was created.

RESULTS

A total of 263 OCD lesions were identified in 259 knees, 66.2% on the medial femoral condyle (MFC), 26.6% on the lateral femoral condyle (LFC), 3.8% on the trochlea, 2.7% on the patella, and 0.8% on the lateral tibia plateau. Male patients made up 57.6% of the sample, which had a mean age of 21.8 years. A very high percentage of patients (77.1%; n = 182) practiced sports, of whom 67.6% (n = 123) were engaged in high-impact sports. The location of the OCD lesions and the leg alignment (n = 110) were significantly correlated: MFC lesions were associated with more varus than valgus alignment (47.5% vs 11.3%) and patients with LFC lesions had more valgus than varus alignment (46.7% vs 20.0%; P = .002). Based on age, smoking, sports activity, and preceding trauma, a multivariable scoring system (0-11 points) was created. An increased risk of lesion instability was associated with an increased score: 29.0% at 0 points and 97.0% at 11 points.

CONCLUSION

This study provides detailed epidemiological data for 236 patients affected by OCD of the knee. Older age, smoking, inactivity, and preceding trauma were predictive for instability of OCD lesions. There was an association between OCD of the MFC and varus malalignment and between OCD of the LFC and valgus malalignment. This finding, in combination with the high percentage of patients practicing high-impact sports, suggests an important role for mechanical overload in the pathogenesis of OCD.

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.

The "hump" a new arthroscopic phenomenon guiding for reliable therapy of osteochondritis dissecans of variable stability status

INTRODUCTION

Despite 150 years of research, there are currently no reliable morphological characteristics that can be used to differentiate between stable and unstable juvenile osteochondritis dissecans (JOCD) lesions in the knee joint. Arthroscopic probing is still the gold standard. In arthroscopic evaluation, a previously undescribed pattern of a cartilaginous convex elevation ("hump") was identified as a new feature and potential sign of JOCD in transition to instability. The aim of the study was to evaluate the clinical outcomes after surgical intervention (drilling) on the "hump".

MATERIALS AND METHODS

In a retrospective case series of sixteen patients with an arthroscopically detectable "hump", the analysis of clinical function scores (Lysholm, Tegner) and morphological MRI monitoring of radiological healing were performed. The assessment of lesion healing was based on pre- and postoperative MRI examinations. The "hump" was defined as an arthroscopically impressive protrusion of the femoral articular surface with a minimally softened, discolored, but intact cartilage margin that, is not mobile upon in the arthroscopic palpation hook test. The primary therapy of choice was drilling of all "humps".

RESULTS

The "hump" could be detected arthroscopically in 16 of 59 JOCD lesions. Specific MRI correlations with the "hump" or arthroscopic unstable lesions could not be detected. Not all "humps" showed signs of MRI-based healing after the drilling, and in some a dissection of the osteochondral flap occurred within the first postoperative year. As a result, secondary refixation became necessary.

CONCLUSION

In the present study, the "hump" was identified as an important differential diagnostic arthroscopic feature of an arthroscopically primarily stable JOCD lesion, potentially placing the lesion at risk of secondary loosening over time. Therefore, drilling alone may not be appropriate in the event of arthroscopic "hump" discovery, but additional fixation may be required to achieve the healing of the lesion.

LEVEL OF EVIDENCE

III.

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.

Classification Systems for Knee Osteochondritis Dissecans: A Systematic Review

OBJECTIVE

Aim of this systematic review was to describe all classification systems for knee osteochondritis dissecans (OCD) lesions, evaluating their accuracy and reliability, as well as their use in the literature on knee OCD.

DESIGN

A systematic review of the literature was performed in July 2021 on PubMed, WebOfScience, and Cochrane Collaboration (library) to describe all published classification systems for knee OCD lesions and quantify the use of these classifications in the literature.

RESULTS

Out of 1,664 records, 30 studies on 33 OCD classifications systems were identified, describing 11 radiographic, 13 MRI, and 9 arthroscopic classifications. The search included 193 clinical studies applying at least one OCD classification, for a total of 7,299 knee OCD cases. Radiographic classifications were applied to 35.8%, MRI to 35.2%, and arthroscopic classifications to 64.2% of the included studies. Among these, in the last two decades, the International Cartilage Repair Society's (ICRS) arthroscopic classification was the most described approach in studies on knee OCD. Overall, there is a lack of data on accuracy and reliability of the available systems.

CONCLUSIONS

Several classifications are available, with ICRS being the most used system over the time period studied. Arthroscopy allows to confirm lesion stability, but noninvasive imaging approaches are the first line to guide patient management. Among these, radiographic classifications are still widely used, despite being partially superseded by MRI, because of its capability to detect the earliest disease stages and to distinguish stable from unstable lesions, and thus to define the most suitable conservative or surgical approach to manage patients affected by knee OCD.

LEVEL OF EVIDENCE

Systematic review, level IV.

Good medium-term functional results in reconstruction of lateral femoral condyle osteochondral lesions

INTRODUCTION

Results of autologous osteochondral graft (mosaicplasty) are well-reported for the medial femoral condyle but much less for the lateral femoral condyle. The main aim of the present study was to assess results specifically for lateral condyle reconstruction. The secondary objective was to compare results according to the two main etiologies: osteochondritis dissecans (OCD) and osteochondral fracture (OCF).

HYPOTHESIS

The study hypothesis was that medium-term functional and radiological results of lateral femoral condyle autologous osteochondral graft are good.

MATERIAL AND METHODS

A single-center retrospective continuous study included 24 patients with symptomatic focal lateral femoral condyle osteochondral lesion treated by osteochondral autograft, at a minimum 24 months' follow-up. Mosaicplasty was performed for lesions <200 mm², with associated fixation for lesions >200 mm² with viable osteochondral fragments. IKDC, Lysholm and KOOS functional scores and pain on visual analog scale (VAS) were collected at last follow-up. Progression toward osteoarthritis was assessed on comparative X-ray.

RESULTS

Twenty patients were analyzed (11 OCD, 9 OCF) at a mean of 66.4±44 months. Mean pain on VAS was 1.8±2 out of 10. Mean subjective IKDC, Lysholm and global KOOS scores were respectively 68.1±26, 76.5±22 and 73.9±21. Two patients showed Ahlbäck grade 2 lateral femorotibial osteoarthritis. Functional results were comparable between OCD and OCF.

CONCLUSION

Reconstruction of lateral femoral condyle osteochondral lesion by osteochondral autograft gave good medium-term functional results, whatever the etiology. Longer-term studies are needed to assess progression toward osteoarthritis and functional deterioration over time.

LEVEL OF EVIDENCE

IV; retrospective study.

Osteochondral lesions of the talar dome: an up-to-date approach to multimodality imaging and surgical techniques

Osteochondral lesions (OCLs) of the talar dome consist of a multifactorial pathology of the articular cartilage and subchondral bone and can result in persistent ankle pain and osteoarthritis (OA). Along with a physical examination and clinical history, an imaging evaluation plays a pivotal role in the diagnosis of these lesions and is fundamental for making treatment decisions and determining prognosis by providing information regarding the size, location, and cartilage and subchondral bone statuses as well as associated lesions and degenerative changes. Multiple surgical techniques for OCLs of the talar dome have been developed in recent decades, including cartilage repair, regeneration, and replacement strategies, and radiologists should be acquainted with their specific expected and abnormal postoperative imaging findings to better monitor the results and predict poor outcomes. The present article proposes a thorough review of the ankle joint anatomy and biomechanics, physiopathology, diagnosis, and treatment of OCLs of the talar dome, highlighting the radiological approach and imaging findings in both pre- and postoperative scenarios.

Osteochondritis Dissecans: Current Understanding of Epidemiology, Etiology, Management, and Outcomes

➤

Osteochondritis dissecans occurs most frequently in the active pediatric and young adult populations, commonly affecting the knee, elbow, or ankle, and may lead to premature osteoarthritis.

➤

While generally considered an idiopathic phenomenon, various etiopathogenetic theories are being investigated, including local ischemia, aberrant endochondral ossification of the secondary subarticular physis, repetitive microtrauma, and genetic predisposition.

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Diagnosis is based on the history, physical examination, radiography, and advanced imaging, with elbow ultrasonography and novel magnetic resonance imaging protocols potentially enabling early detection and in-depth staging.

➤

Treatment largely depends on skeletal maturity and lesion stability, defined by the presence or absence of articular cartilage fracture and subchondral bone separation, as determined by imaging and arthroscopy, and is typically nonoperative for stable lesions in skeletally immature patients and operative for those who have had failure of conservative management or have unstable lesions.

➤

Clinical practice guidelines have been limited by a paucity of high-level evidence, but a multicenter effort is ongoing to develop accurate and reliable classification systems and multimodal decision-making algorithms with prognostic value.

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.

Interobserver reliability of the classification of capitellar osteochondritis dissecans using magnetic resonance imaging

AIM

(1) To determine the interobserver reliability of magnetic resonance classifications and lesion instability criteria for capitellar osteochondritis dissecans lesions and (2) to assess differences in reliability between subgroups.

METHODS

Magnetic resonance images of 20 patients with capitellar osteochondritis dissecans were reviewed by 33 observers, 18 orthopaedic surgeons and 15 musculoskeletal radiologists. Observers were asked to classify the osteochondritis dissecans according to classifications developed by Hepple, Dipaola/Nelson, Itsubo, as well as to apply the lesion instability criteria of DeSmet/Kijowski and Satake. Interobserver agreement was calculated using the multirater kappa (k) coefficient.

RESULTS

Interobserver agreement ranged from slight to fair: Hepple (k = 0.23); Dipaola/Nelson (k = 0.19); Itsubo (k = 0.18); DeSmet/Kijowksi (k = 0.16); Satake (k = 0.12). When classifications/instability criteria were dichotomized into either a stable or unstable osteochondritis dissecans, there was more agreement for Hepple (k = 0.52; p = .002), Dipaola/Nelson (k = 0.38; p = .015), DeSmet/Kijowski (k = 0.42; p = .001) and Satake (k = 0.41; p < .001). Overall, agreement was not associated with the number of years in practice or the number of osteochondritis dissecans cases encountered per year (p > .05).

CONCLUSION

One should be cautious when assigning grades using magnetic resonance classifications for capitellar osteochondritis dissecans. When making treatment decisions, one should rather use relatively simple distinctions (e.g. stable versus unstable osteochondritis dissecans; lateral wall intact versus not intact), as these are more reliable.

Osteochondritis Dissecans in the Knee of Skeletally Immature Patients: Rates of Persistent Pain, Osteoarthritis, and Arthroplasty at Mean 14-Years' Follow-Up

OBJECTIVE

Osteochondritis dissecans (OCD) is a knee disorder of predominately pediatric populations. Because of low incidence, it has traditionally been difficult to study OCD. The purpose of this study was to report long-term outcomes of skeletally immature OCD lesions and determine risk factors for persistent knee pain at final follow-up.

DESIGN

A geographic database of more than 500,000 patients was reviewed to identify patients with knee OCD. Clinical course including operative management, persistent knee pain, and total knee arthroplasty (TKA) were analyzed through review of radiographs, magnetic resonance images, and physician notes.

RESULTS

A total of 95 skeletally immature patients (70 male, 25 female, mean age 12.5 ± 2.0 years) were followed for a mean of 14 years (range, 2-40 years). Fifty-three patients were treated operatively and 42 were treated nonoperatively. At final follow-up, 13 patients noted persistent knee pain, 8 treated operatively versus 5 treated nonoperatively. Risk factors for knee pain were female gender, patellar lesions, and unstable lesions. Four patients (8%) treated operatively and 2 patients (5%) treated nonoperatively developed symptomatic osteoarthritis at a mean of 28.6 years following diagnosis. Three patients underwent TKA at a mean age of 52 years, significantly younger than that observed for primary TKA at our institution (P = 0.004).

CONCLUSIONS

Skeletally immature OCD patients have promising histories, with an estimated 14% risk of persistent knee pain, 6% symptomatic osteoarthritis, and 3% conversion to TKA at 14 years' mean follow-up. Females, patellar lesions, and unstable lesions demonstrated increased persistent knee pain risk. Patients with OCD undergo TKA at a significantly younger age than the general population.

Three-Dimensional Quantitative Magnetic Resonance Imaging of Epiphyseal Cartilage Vascularity Using Vessel Image Features: New Insights into Juvenile Osteochondritis Dissecans

We introduce a quantitative measure of epiphyseal cartilage vascularity and examine vessel networks during human skeletal maturation. Understanding early morphological changes in the distal femoral condyle is expected to provide information on the pathogenesis of developmental diseases such as juvenile osteochondritis dissecans.

Methods

Twenty-two cadaveric knees from donors ranging from 1 month to 10 years of age were included in the study. Images of bone, cartilage, and vascularity were acquired simultaneously with a 3-dimensional gradient-recalled-echo magnetic resonance imaging (MRI) sequence. The secondary ossification center volume and total epiphysis cartilage volume ratio and articular-epiphyseal cartilage complex and epiphyseal cartilage widths were measured. Epiphyseal cartilage vascularity was visualized for 9 data sets with quantitative susceptibility mapping and vessel filtering, resulting in 3-dimensional data to inform vessel network segmentation and to calculate vascular density.

Results

Three distinct, non-anastomosing vascular networks (2 peripheral and 1 central) supply the distal femoral epiphyseal cartilage. The central network begins regression as early as 3 months and is absent by 4 years. From 1 month to 3 years, the ratio of central to peripheral vascular area density decreased from 1.0 to 0.5, and the ratio of central to peripheral vascular skeletal density decreased from 0.9 to 0.6. A narrow, peripheral vascular rim was present at 8 years but had disappeared by 10 years. The secondary ossification center progressively acquires the shape of the articular-epiphyseal cartilage complex by 8 years of age, and the central areas of the medial and lateral femoral condyles are the last to ossify.

Conclusions

Using cadaveric pediatric knees, we provide quantitative, 3-dimensional measures of epiphyseal cartilage vascular regression during skeletal development using vessel image features. Central areas with both early vascular regression and delayed ossification correspond to predilection sites of juvenile osteochondritis dissecans in this limited case series. Our findings highlight specific vascular vulnerabilities that may lead to improved understanding of the pathogenesis and better-informed clinical management decisions in developmental skeletal diseases.

Clinical Relevance

This paradigm shift in understanding of juvenile osteochondritis dissecans etiology and disease progression may critically impact future patient management. Our findings highlight specific vascular vulnerabilities during skeletal maturation in a group of active young patients seen primarily by orthopaedic surgeons and sports medicine professionals.

Intra-articular administration of peripheral blood stem cells with platelet-rich plasma regenerated articular cartilage and improved clinical outcomes for knee chondral lesions

PURPOSE

To determine whether intra-articular injections of peripheral blood stem cells improved the regeneration of articular cartilage in patients with osteochondral knee injuries.

METHODS

This prospective study included 20 patients with grade 3b knee osteochondral lesions who underwent knee arthroscopies. All were white, and all had performed physical activity at least five times a week. International Knee Documentation Committee (IKDC) and visual analog scale scores were recorded before surgery, six months and one year after surgery, and then yearly until five years after surgery. Magnetic resonance imaging scans were obtained six months preoperatively and then yearly and were evaluated by musculoskeletal radiologists blinded to the patient data. Tissue repair was quantified using the International Cartilage Repair Society morphologic score system. Unpaired t-tests were used for comparisons between the time points.

RESULTS

The mean preoperative IKDC score was 50.5 (42-61). At the six-month follow-up, the mean values were 60.79 (P = 0.32) and 90.97. At the six-month follow-up, the mean values were 70.8 (P = 0.043). At the end of the five-year follow-up, the IKDC was 82.2 (P = 0.024). At five-year follow-up, the visual analog scale score was 1.1 (P = 0.0018). The main morphologic score system score was 3.2 preoperatively and 9.7 ± 1.6 at five-year follow-up (P = 0.0021). No infection, tumors, or synovitis were reported at the end of the follow-up.

CONCLUSIONS

Intra-articular peripheral blood stem cells with platelet-rich plasma regenerated articular cartilage and improved clinical outcomes for knee chondral lesions at five years of follow-up.

Acetabular Delamination: Epidemiology, Histological Features, and Treatment

OBJECTIVE

The International Cartilage Repair Society classification is the one mainly used to define chondral defects. However, this classification does not include delamination. The objective of the study is to describe the characteristics of this lesion to better explain its classification in the context of chondral lesions of the hip.

DESIGN

We performed a retrospective analysis of 613 patients who underwent hip arthroscopy. In this group, the incidence, localization, histological characteristics, and association to femoroacetabular impingement as well as to other intraarticular lesions of acetabular delamination (AD) were analyzed. Preoperative magnetic resonance imaging accuracy and the different treatment options were also evaluated.

RESULTS

In our series, the incidence of the AD was 37% (226 patients over 613). The average age of this group was significantly lower (39.3 years) than the entire group of patients. Isolated cam (P < 0.01) and pincer morphologies (P < 0.05) had a significant statistical association with the AD. This lesion was primarily localized at the acetabular chondrolabral junction, mainly on the anterosuperior quadrant. The intraarticular lesions more frequently associated to AD were labral lesions (94.25%, P < 0.01), ligamentum teres lesions (28.32%, P < 0.05), and femoral head chondral lesions (19.9%, P < 0.01). The histological examination of the AD was characterized by hypocellularity and structural disorder of the matrix, with fissures. Treatment remains controversial.

CONCLUSION

AD represents an intermediate stage in chondral damage and can be classified as a "2a" grade lesion. Histological examination confirms the intermediate and progressive character of this injury.

Treatment of unstable knee osteochondritis dissecans in the young adult: results and limitations of surgical strategies-The advantages of allografts to address an osteochondral challenge

Joint surface incongruence resulting from osteochondritis dissecans (OCD) alters the articular physiologic congruence, increasing the contact stress on adjacent joint surfaces and accelerating wear and the cascade of joint degeneration. Accordingly, the restoration of articular surface integrity is of major importance, especially in young adults where, in lesions left untreated or following simple fragment excision, early osteoarthritis can be anticipated. Therefore, the treatment algorithm in unstable knee OCD of the young adult foresees surgical options to restore the articular surface. Several procedures have been proposed, including refixation of the detached fragment bone marrow stimulation, osteochondral autograft implantation, fresh osteochondral allograft transplantation, and cell-based or cell-free regenerative techniques. The aim of this review was to summarize the evidence for these surgical strategies, reporting their results and limitations. The overall evidence documents positive results for each of the assorted surgical procedures applied to treat unstable OCD, thus indicating support for their selected use to treat osteochondral defects paying particular attention to their specific indications for the lesion characteristics. The fixation of a good quality fragment should be pursued as a first option, while unfixable small lesions may benefit from autografts. For large lesions, available cell-based or cell-free osteochondral scaffold are a feasible solution but with limitation in terms of regenerated tissue quality. In this light, fresh allografts may offer articular surface restoration with viable physiologic osteochondral tissue providing a predictably successful outcome, and therefore they may currently represent the most suitable option to treat unstable irreparable OCD lesion in young adults. LEVEL OF EVIDENCE: V.

Limitation of in-situ arthroscopic fixation for stable juvenile osteochondritis dissecans in the knee

Current treatment algorithms for stable juvenile osteochondritis dissecans (JOCD) of the knee have not been established. For arthroscopically stable lesion, in-situ arthroscopic fixation with bioabsorbable pins was introduced as a more desirable approach because of less surgical morbidity and faster recovery. However, there is a paucity of literature that concludes on its efficacy. The aim of this study is to determine the efficacy and limitation of in-situ arthroscopic fixation on stable JOCD lesion in the knee. Ninety-six patients with 110 affected knees were reviewed. Subsequently, patients who underwent in-situ arthroscopic fixation for arthroscopically stable JOCD lesions were grouped for further analysis. Arthroscopic lesion stability was graded according to the Guhl's grading system from the surgical description of each lesion. The grade I and II were defined as 'stable' lesions. The lesion status was also evaluated with the MRI grading system described by Dipaola in preoperative images retrospectively. The grade I and II lesions were also defined as 'stable' and more than III as 'unstable'. Clinical outcomes were evaluated by the Lysholm score at the final office visit. If the patient had a revision surgery, the case was classified as a complete failure. There were 13 lesions in 13 patients with open physis treated with in-situ arthroscopic fixation using bioabsorbable pins. In this population, radiographical lesion status and the Lysholm score were significantly improved in 10 cases (preoperative: 77.5±11.2, postoperative: 98.9±3.1, P=0.002); however, we found three revision cases (failure rate, 23%). Of these revision cases, all lesions were graded as 'unstable' in MRI. In this series, the failure rate was 23% for in-situ arthroscopic fixation for arthroscopically stable JOCD lesion of the knee. Because of the potential risk for underestimation of lesion instability, we strongly suggest that this less invasive approach should be chosen with great care for the lesion that presents arthroscopically stable, but as unstable status on MRI.

LEVEL OF EVIDENCE

Level IV, case series.

Sustained Results in Long-Term Follow-Up of Autologous Chondrocyte Implantation (ACI) for Distal Femur Juvenile Osteochondritis Dissecans (JOCD)

INTRODUCTION

Concern regarding ability of autologous chondrocyte implantation (ACI) to correct for the bone and cartilage pathology of knee juvenile osteochondritis dissecans (JOCD) exists. The purpose of this study was to determine long-term, patient-based outcomes of ACI treatment of JOCD in young patients. Authors hypothesized long-term outcomes are comparable to reported mid-term outcomes.

METHODS

A single institution, longitudinal cohort study design combining medical record review and outcome surveys was used. Inclusion criteria included isolated JOCD diagnosis, failed primary healing of operatively treated JOCD, ACI surgery > 5 years ago, and ≤20 years of age at time of ACI.

RESULTS

10/26 eligible patients (38.5%) participated (M: F = 5:5, age at ACI: 18.3 ± 2.5 y, current age: 30.8 ± 5.1 y, and current BMI: 24.6 ± 2.1). Follow-up was 12.0 ± 4.5 y. Lesion size at ACI was 9.1 ± 1.9 cm². Femoral condyle location was medial = 6 and lateral = 4. All required treatment at some point for knee symptoms after ACI. During the past one year, four patients required treatment. Patient reported outcome scores at 12 years following ACI were IKDC score: 73.0 ± 3.6, KOOS scores including pain [88.7 ± 2.3], symptoms [78.2 ± 4.6], activity of daily living [94.7 ± 1.9], function, sports, and recreational activities [73.0 ± 5.3], and quality of life [57.5 ± 5.8], and Modified Cincinnati Knee Rating score was 77.9 ± 4.1. A moderate to good relationship was found between KOOS symptoms and BMI and lesion size. Function, sports, and recreational activities of the KOOS were greater in participants who had ≤1 lesion prior to ACI procedures (p = 0.044).

CONCLUSION

This study of ACI treatment of knee JOCD patients confirms sustained, long-term results. Number of lesions prior to ACI procedure influenced status of function, sports, and recreational activities.

Incidence of Coexisting Talar and Tibial Osteochondral Lesions Correlates With Patient Age and Lesion Location

Background:

The incidence of coexisting osteochondral lesions (OCLs) of the tibia and talus has been negatively correlated with successful clinical outcomes, yet these lesions have not been extensively characterized.

Purpose:

To determine the incidence of coexisting tibial and talar OCLs, assess the morphologic characteristics of these lesions, and evaluate whether these characteristics are predictive of outcome.

Study Design:

Case series; Level of evidence, 4.

Methods:

A total of 83 patients who underwent surgery for a talar OCL were evaluated for coexisting OCLs of the distal tibia with preoperative magnetic resonance images. Size, location, containment, International Cartilage Repair Society (ICRS) grade, patient age, and patient sex were analyzed for predictors of coexisting lesions or patient outcome. The talar and tibial surfaces were each divided into 9 zones, with 1 corresponding to the most anteromedial region and proceeding laterally and then posteriorly. The Foot and Ankle Outcome Score (FAOS) was evaluated pre- and postoperatively.

Results:

Twenty-six patients (31%) had coexisting tibial and talar OCLs, with 9 (35%) identified as kissing lesions. Age correlated with coexisting lesion incidence, as older patients were more likely to have a coexisting tibial OCL (P = .038). More than half of talar OCLs were found in zone 4 (61%), whereas the majority of tibial OCLs were located in zones 2, 4, and 5 (19% each). Patients with coexisting lesions were more likely to have a lateral talar OCL (P = .028), while those without a coexisting tibial lesion were more likely to have a talar OCL in zone 4 (P = .016). There was no difference in FAOS result or lesion size between patients with and without coexisting OCLs, but patients with coexisting lesions were more likely to have an ICRS grade 4 talar OCL (P = .034). For patients with coexisting lesions, kissing lesions were more likely to be located in zone 6 (P = .043). There was no difference in OCL size or containment between kissing and nonkissing coexisting OCLs.

Conclusion:

The incidence of coexisting talar and tibial OCLs may be more prevalent than what previous reports have suggested, with older patients being more likely to present with this pathology. The location of a talar OCL correlates with the incidence of a coexisting tibial OCL.

Insights into the Epiphyseal Cartilage Origin and Subsequent Osseous Manifestation of Juvenile Osteochondritis Dissecans with a Modified Clinical MR Imaging Protocol: A Pilot Study

Purpose To retrospectively determine if a modified clinical magnetic resonance (MR) imaging protocol provides information on the origin of juvenile osteochondritis dissecans (JOCD) lesions and allows for staging on the basis of the proposed natural history of JOCD to better guide clinical management of the disease. Materials and Methods This institutional review board-approved, HIPAA-compliant, retrospective study was performed in 13 consecutive patients (mean age, 14.9 years; age range, 10-22 years; nine male and four female patients) and one additional comparative patient (a 44-year-old man), in which 19 knees with 20 JOCD lesions were imaged. Seventeen lesions occurred in the medial femoral condyle, two occurred in the lateral femoral condyle, and one occurred in the medial trochlea. The clinical 3-T MR imaging protocol was supplemented with a routinely available multiecho gradient-recalled-echo sequence with the shortest attainable echo time of approximately 4 msec (T2* mapping). Results At the earliest manifestation, the lesion was entirely cartilaginous (n = 1). Subsequently, primary cartilaginous lesions within the epiphyseal cartilage developed a rim calcification that originated from normal subjacent bone, which defined a clear cleft between the lesion progeny and the parent bone (n = 9). Secondarily, progeny lesions became ossified (n = 7) while at the same time forming varying degrees of osseous bridging and/or clefting with the parent bone. Two healed lesions with a linear bony scar and one detached lesion were identified. Conclusion The modified MR imaging protocol allowed for identification of the epiphyseal cartilage origin and subsequent stages of ossification in JOCD. The approach allows further elucidation of the natural history of the disease and may better guide clinical management. ^© RSNA, 2016.