Osteochondritis dissecans of the knee in children and adolescents

Osteochondrosis in horses: An overview of genetic and other factors

Osteochondrosis (OC) is a frequent manifestation of developmental orthopaedic disease, and its severe clinical presentation is known as OC dissecans (OCD). OC is defined as a disruption of the endochondral ossification process in the epiphyseal cartilage, and this disease has been reported in different mammalian species, including humans, dogs, pigs, and horses. OCD is an important cause of lameness in sport horses and is a common cause of impaired orthopaedic potential, whose clinical signs may be of minimal magnitude or manifest as severe joint effusion or clinically noticeable lameness. The aetiology of OCD is unknown, although it has traditionally been considered to be multifactorial. In addition to genetic factors, associated factors include both non-genetic elements such as rapid growth, nutrition, trauma, anatomical conformation, and biomechanics. Since the prevalence of the disease varies greatly depending on the horse breed, from 13% in Swedish Warmblood to 53% in Lusitano breed, genetic factors have a great relevance in the appearance and development of OCD in horses. Many genetic modifications have been related, and the genes involved can be grouped into five clusters, related to fundamental functions for the correct development and regeneration of cartilage, such as collagen, laminin, cell signalling, matrix turnover, and transcriptional regulation. Changes in genes such as COL3A1, COL5A1, COL5A2, COL24A1, COL27A1 (collagen cluster), LAMB1 (laminin cluster), PTH, PHT receptors, and IHH (cell signalling), and genes encoding matrix metalloproteinases have been related to the occurrence and severity of diseases in different equine breeds. This review summarises the main factors associated with OC in horses, with particular emphasis on genetic factors.

Juvenile Osteochondritis Dissecans: Current Concepts

Osteochondritis dissecans (OCD) primarily damages the subchondral bone, leading to damage to the articular cartilage. Juvenile OCD (JOCD) of the knee is limited to skeletally immature and young patients with open growth plates on radiographs. We conducted a review of PubMed articles up until March 16, 2024, using a combination of the following keywords: knee, juvenile, and osteochondritis dissecans. This narrative review included a total of 56 relevant articles that investigated the etiology, incidence, clinical presentation, imaging, classification, and treatment of JOCD of the knee in patients less than 20 years of age. The exact etiology is controversial. Most authors believe that the disease involves multiple theories, such as ischemia, recurrent trauma, and genetic predisposition. Radiographs, the first imaging study in this patient group, cannot determine the stability or instability of the surface cartilage of the OCD lesion. As a result, MRI has become a recommended diagnostic method for determining OCD stability and providing important information for determining a treatment plan. For stable JOCD lesions, nonsurgical treatment is often advised. For unstable and stable lesions that do not respond to nonsurgical treatment, several surgical techniques with good healing rates are available.

S.P.O.R.R.T.-A Comprehensive Approach to the Assessment and Non-Operative Management of Overuse Knee Conditions in Youth Athletes

PURPOSE OF REVIEW

The evaluation of a young athlete with an overuse injury to the knee involves a comprehensive approach. There are a number of elements to consider including assessments of skeletal maturity (biologic maturation), workload (training load + competition load), sport specialization status, and biomechanics. The type of injury and treatment, as well as future prognosis, may be influenced by these and other factors.

RECENT FINDINGS

Calculating the percentage of predicted adult height (PPAH) is a valuable tool in assessing overuse injury patterns and diagnoses in youth athletes. Modifiable and non-modifiable overuse injury risk factors require monitoring from clinicians as young athletes mature and develop over time. Training and rehabilitation programs should be adapted to account for these. In this manuscript, we seek to introduce a novel, comprehensive approach: S.P.O.R.R.T. (Skeletal Maturity, Prior Injury Risk, One Sport Specialization, Rehabilitation, Return to Play, Training Recommendations) (Fig. 1). Overuse, non-traumatic injuries to the knee in youth athletes will be presented in a case-based and evidence-based model to provide a framework for a comprehensive approach to the assessment and treatment of youth athletes with overuse injuries.

Juvenile Osteochondritis Dissecans of the Knee Joint: Midterm Clinical and MRI Outcomes of Arthroscopic Retrograde Drilling and Internal Fixation with Bioabsorbable Pins

OBJECTIVE

This study aimed to assess the clinical and radiographic outcomes of juvenile patients who suffered from stage II or III osteochondritis dissecans (OCD) of the knee and underwent arthroscopic retrograde drilling and internal fixation with bioabsorbable pins.

DESIGN

Medical and radiological records from patients aged 11 to 16 years, who underwent arthroscopic treatment for OCD lesions of the knee in 2 tertiary hospitals, were retrospectively reviewed. The procedure was indicated by persistent pain and by magnetic resonance imaging (MRI). All patients underwent retrograde drilling and arthroscopic fixation of the lesion with bioabsorbable pins. MRI was conducted at least 1 year postoperative in all patients to evaluate healing. Functional outcomes were evaluated through the Visual Analogue Scale (VAS) for pain, Lysholm, and IKDC (International Knee Documentation Committee) scores.

RESULTS

A total of 40 patients, with an average age of 13.1 years (range = 11-16 years) and an average follow-up of 6.6 years (range = 3-13 years) were reviewed. MRI findings confirmed the healing of the lesion in 36 out of the 40 (90%) patients. In particular, the healing rate was 95% (20/21) and 84% (16/19) for stage II and stage III, respectively. Lysholm, IKDC, and VAS scores revealed a statistically significant improvement (P < 0.05) at final follow-up in comparison to preoperative status. No infection, knee stiffness, or other complication was recorded.

CONCLUSIONS

Retrograde drilling combined with internal fixation with bioabsorbable pins, of stages II and III OCD lesions of the knee provides good to excellent outcomes to juvenile patients, with a high healing rate.

Bioabsorbable Unsintered Hydroxyapatite/Poly-l-Lactic Acid Pin Fixation of Osteochondritis Dissecans in Adolescents: Initial Experiences

BACKGROUND

This study sought to retrospectively evaluate the clinical and magnetic resonance imaging (MRI) outcomes of u-HA/PLLA pin (u-HA/PLLA: hydroxyapatite/poly-L-lactic acid) pin fixation of unstable osteochondritis dissecans (OCD) lesions of the knee.

METHODS

Seven adolescent patients (four females and three males) with arthroscopically unstable OCD lesions of the knee were included. The mean age at diagnosis was 13.1 years. Clinical results were evaluated preoperatively and during follow-up using the Ogilvie-Harris score (0 - 15 points). MRI scans were performed preoperatively and during follow-up, with results evaluated using the Dipaola classification (grades 1 - 4). Mean follow-up time was 29 months.

RESULTS

The median Ogilvie-Harris score improved from 13 points (range: 10 - 14 points) to 15 points (range: 13 - 15 points). Separately, the median Dipaola score improved from 3 points (range: 2 - 4 points) to 1 point (range: 1 - 4 points). No complications such as infection, synovitis, or intra-articular adhesion were observed.

CONCLUSIONS

Initial experiences using bioabsorbable u-HA/PLLA pins for the refixation of unstable OCD lesions in adolescents in the knee are promising, and MRI provides excellent monitoring of healing.

Ipsilateral Osteochondritis Dissecans-like Distal Femoral Lesions in Children with Blount Disease: Prevalence and Associated Findings

Purpose

Our goal was to assess the prevalence of ipsilateral distal femoral osteochondritis dissecans (OCD)-like lesions in children with Blount disease, including factors associated with this finding.

Materials and methods

Characteristics of patients with an OCD-like lesion on an imaging study [(X-ray and/or magnetic resonance imaging (MRI)] were compared with those without such a finding.

Results

Over a 12-year period, 6/63 (10%) skeletally immature patients (9/87 limbs) with Blount disease had an OCD-like lesion visible on plain radiographs. Based on available MRI, 7/37 (19%) patients or 10/53 (19%) limbs had an OCD-like distal femoral lesion. All lesions were noted in the posterior third of the weight-bearing portion of the medial femoral condyle with intact overlying articular cartilage. All patients with OCD-like lesions were followed for an average of 1.9 years (range: 1–2.6 years), and complete radiographic resolution of lesion was noted in 7/9 limbs (78%). There was no association of the presence of OCD-like lesion with early- vs late-onset disease, gender, age at imaging, laterality, magnitude of deformity [mean mechanical axis deviation (MAD) 63.3 vs 71.9 mm], mean mechanical lateral distal femoral angle (mLDFA; 91.3 vs 89.7°), and mean medial proximal tibial angle (MPTA; 71.7 vs 71.8°). Children with an OCD-like lesion tended to have a lower mean body mass index (BMI; 21 vs 36, p = 0.003).

Conclusion

The overall prevalence of OCD-like lesions in the medial femoral condyle in children with Blount disease lesions is 10% using plain radiographs and at least 19% on MRI. Based on the numbers available, we were unable to demonstrate any associations between the presence of such lesions and the patient’s age, gender, or magnitude of varus deformity. Further research is needed to fully ascertain the aetiology and natural history of these benign appearing osteochondral imaging findings in children with Blount disease. Our current data support that these lesions do resolve with time and that no surgical intervention targeted at the femoral OCD-like lesion is warranted.

Level of evidence

Diagnostic study Level III.

How to cite this article

Edobor-Osula F, Wenokor C, Bloom T, et al. Ipsilateral Osteochondritis Dissecans-like Distal Femoral Lesions in Children with Blount Disease: Prevalence and Associated Findings. Strategies Trauma Limb Reconstr 2019;14(3):121–125.

The Influence of Physeal Status on Rate of Reoperation After Arthroscopic Screw Fixation for Symptomatic Osteochondritis Dissecans of the Knee

PURPOSE

To determine if physeal status or other preoperative or intraoperative variables influence the failure rate after arthroscopic reduction and internal fixation of osteochondritis dissecans (OCD) lesions in the knee.

METHODS

Consecutive patients undergoing screw fixation of osteochondral fragments from OCD by a single surgeon from 2005 to 2015 with a minimum 2-year follow-up were included. Demographic, preoperative imaging, and intraoperative data were analyzed to determine risk factors associated with failure, which was defined as the need for a revision reoperation or arthroplasty after initial OCD fixation.

RESULTS

A total of 45 knees met the inclusion criteria, including 26 skeletally mature patients and 19 patients with incompletely closed physes on preoperative imaging. The mean ages of the skeletally mature and immature groups were 18.3 ± 2.5 years and 14.9 ± 2.2 years, respectively (P < .001), and the mean body mass index values were 24.3 ± 3.6 and 23.2 ± 4.0, respectively (P = .432). We excluded 10 patients from the survivorship analysis because they had less than 2 years' follow-up. No statistically significant difference in failure rates was found between skeletally mature and immature individuals (30% and 40%, respectively; P = .721). The only factor significantly associated with fixation failure was undergoing a prior surgical procedure to address the OCD lesion (P = .038). Kaplan-Meier analysis showed rates of overall survivorship from revision reoperations of 88.6% at 1 year and 68.8% at 5 years.

CONCLUSIONS

Outcomes after internal fixation of OCD fragments are guarded, with a fragment survival rate of 65.7% at a mean of 4.1 years' follow-up. No difference in fragment survival was noted in skeletally mature versus immature patients. The only independent risk factor identified for fixation failure was the number of previous operations. LEVEL OF EVIDENCE: Level IV, case series with subgroup analysis.

Internal Fixation of Osteochondritis Dissecans of the Knee Leads to Good Long-Term Outcomes and High Degree of Healing without Differences between Fixation Devices

The aim of the present study is to describe results at long-term follow-up of internal fixation of unstable Osteochondritis Dissecans (OCD) achieved with three different fixation devices in skeletally mature knees. A retrospective cohort study was performed at 5 to 19 years follow-up. Patient-reported questionnaires were collected at the final follow-up. Postoperative X-rays and MRIs were evaluated for healing of the lesion and articular degeneration. An arthroscopic second look was performed in 74.3% of the cases. Failures were reported as reintervention to address the osteochondral lesion or poor functional outcomes at the last follow-up. A total of 39 subjects with a median follow-up of 10.7 years were included. Herbert screws were used in 51.2% of the cases, bioabsorbable nails in 25.7% of the cases and cannulated screws in 23.1% of the cases. No differences were observed in terms of the clinical score (International Knee Documentation Committee (IKDC) p = 0.211; Lysholm p = 0.197), radiographic union (p = 0.102) or radiographic degeneration (p = 0.238) between the three different fixation devices. Arthroscopic second look found complete stability of the lesions in all 29 cases evaluated. The mean postoperative Lysholm score was 83 (range = 33-100) and IKDC score was 79 (range = 39-100). Radiographic union was seen in 74% of the cases. Lack of radiographic union was correlated with worst functional scores. A failure rate of 20.5% was found: four reinterventions were performed, and four patients had poor scores at last follow up. This study shows that internal fixation of condylar OCD in skeletally mature patients provides good long-term clinical results and a high degree of healing regardless of the dimensions of the lesion and type of fixation.

Neglected Pediatric Osteochondral Fracture Dislocation of the Patella

Pediatric osteochondral fracture dislocation of the patella is sometimes difficult to diagnose on the basis of physical examination or plain film radiography. Magnetic resonance imaging plays an important role in its early diagnosis, and early treatment can prevent damage to the articular cartilage as well as decrease the dislocation rate. Currently, many treatment choices have been reported with good results, but there is no consensus on which treatment option may lead to the best outcome. Herein, we describe the case of a 14-year-old girl with neglected osteochondral fracture dislocation of the patella. The outcome was optimal on the basis of a 2-year postoperative follow-up; thus, we believe that fixation with headless screws is a simple and effective method if the fracture fragment is large enough.

Allogenic umbilical cord blood-derived mesenchymal stem cells implantation for the treatment of juvenile osteochondritis dissecans of the knee

BACKGROUND

Osteochondritis dissecans (OCD) is a pathologic condition accompanied by the gradual destruction of subchondral bone and defects in the overlying articular cartilage.This case series reports the results of allogenic human umbilical cord blood-derived mesenchymal stem cell (hUCB-MSC) implantation for the treatment of osteochondral defect in two cases of juvenile osteochondritis dissecans.

CASE PRESENTATION

Two patients with osteochondral defect of the knee recovered from the disease enough to begin major exercise 1 year after hUCB-MSCs implantation. The IKDC, VAS, and Tegner score of the two patients showed an excellent improvement and concurrent arthroscopy was performed; cartilage regeneration of ICRS grade 1 similar to normal was observed. The modified two-dimensional MOCART scores increased in both cases over time.

CONCLUSION

This is the first case series detailing the results of treating juvenile OCD lesions using hUCB-MSCs. This could be an option for treating juvenile OCD.

[Magnetic resonance imaging following cartilage repair of focal chondral lesions]

BACKGROUND

Focal cartilage lesions are common pathologies of weight-bearing joints. Clinical presentation ranges from asymptomatic patients to severe, pain-related movement deficits. Moreover, focal chondral lesions are risk factors for the development of osteoarthritis. There are various treatment options involving both surgical and nonsurgical treatments. Musculoskeletal radiologists should be aware of the various surgical options as well as the postsurgical imaging characteristics to depict whether the encountered imaging findings reflect the normal postoperative course or are indicative of a treatment failure.

OBJECTIVES

We aim to describe the most common surgical procedures for the repair of focal cartilage lesions and their typical postsurgical appearance on MRI studies.

MATERIALS AND METHODS

The literature in PubMed was searched with the terms "focal articular cartilage lesions", "chondral lesions", "MOCART", "Microfracture", "Osteochondral Autograft Transfer", "mosaicplasty", "Osteochondral Allograft Transplantation", "OATS", "OCT", "Autologous Chondrocyte Implantation", "ACI", "Matrix-Assisted Chondrocyte Implantation", "Autologous Matrix-induced Chondrogenesis".

RESULTS

Surgical methods for the treatment of focal cartilage lesions as well as the MR imaging features are explained.

Overuse injuries in sport: a comprehensive overview

BACKGROUND

The absence of a single, identifiable traumatic cause has been traditionally used as a definition for a causative factor of overuse injury. Excessive loading, insufficient recovery, and underpreparedness can increase injury risk by exposing athletes to relatively large changes in load. The musculoskeletal system, if subjected to excessive stress, can suffer from various types of overuse injuries which may affect the bone, muscles, tendons, and ligaments.

METHODS

We performed a search (up to March 2018) in the PubMed and Scopus electronic databases to identify the available scientific articles about the pathophysiology and the incidence of overuse sport injuries. For the purposes of our review, we used several combinations of the following keywords: overuse, injury, tendon, tendinopathy, stress fracture, stress reaction, and juvenile osteochondritis dissecans.

RESULTS

Overuse tendinopathy induces in the tendon pain and swelling with associated decreased tolerance to exercise and various types of tendon degeneration. Poor training technique and a variety of risk factors may predispose athletes to stress reactions that may be interpreted as possible precursors of stress fractures. A frequent cause of pain in adolescents is juvenile osteochondritis dissecans (JOCD), which is characterized by delamination and localized necrosis of the subchondral bone, with or without the involvement of articular cartilage. The purpose of this compressive review is to give an overview of overuse injuries in sport by describing the theoretical foundations of these conditions that may predispose to the development of tendinopathy, stress fractures, stress reactions, and juvenile osteochondritis dissecans and the implication that these pathologies may have in their management.

CONCLUSIONS

Further research is required to improve our knowledge on tendon and bone healing, enabling specific treatment strategies to be developed for the management of overuse injuries.

Evaluation and management of knee pain in young athletes: overuse injuries of the knee

Recurrent or chronic activity related knee pain is common in young athletes. Numerous intrinsic conditions affecting the knee can cause such pain. In addition, knee pain can be referred pain from low back, hip or pelvic pathology. The most common cause of knee pain in young athletes is patellofemoral pain syndrome, or more appropriately termed idiopathic anterior knee pain. Although, numerous anatomical and biomechanical factors have been postulated to contribute the knee pain in young athletes, the most common underlying reason is overuse injury. In this paper, we have reviewed selected conditions that case knee pain in athletes, including anterior knee pain syndrome, Osgood-Schlatter disease, Sinding-Larsen-Johanssen syndrome, juvenile osteochondritis dissecans (JOCD), bipartite patella, plica syndrome, and tendonitis around the knee.

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.

Reliability of predictive models for non-operative healing potential of stable juvenile osteochondritis dissecans knee lesions

BACKGROUND

While juvenile osteochondritis dissecans (JOCD) lesions have greater healing potential than equivalent lesions in adults, only 50% of JOCD lesions demonstrate radiographic healing after six months of non-operative treatment. Two previous studies have produced nomograms to predict a patient's probability of healing with non-operative treatment based on patient and lesion characteristics. The purpose of this study was to determine inter- and intra-observer reliability of the predictive nomograms.

METHODS

A consecutive series of 34 skeletally immature patients (40 knees), who underwent non-operative treatment for stable JOCD lesions was retrospectively reviewed. At two time points at least one week apart, two medical students, two orthopaedic surgeons, and a radiologist made measurements of the JOCD lesions. These measurements, along with patient ages and pain type, were used to generate a point value for each lesion based on both nomograms. Intra-class correlations (ICCs) were calculated to determine inter- and intra-rater reliability.

RESULTS

We found near perfect intra-rater correlation (ICC) for all raters' individual OCD measurements, as well as total point score for the two nomograms (ICC range, 0.780-0.929). Additionally, there was near perfect inter-rater reliability among raters for total scores and individual components of each nomogram (ICC range, 0.721-0.974).

CONCLUSIONS

There is high inter- and intra-rater reliability for both point systems for predicting healing of JOCD lesions. Clinicians should be aware of these as tools to help guide decision making in patients with JOCD lesions.

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

RATIONALE AND OBJECTIVES

In this retrospective case series, we utilize arthroscopy as the gold standard to determine if magnetic resonance imaging (MRI) of the knee can predict osteochondritis dissecans (OCD) lesion stability, the most important information to guide patient treatment decisions. It is hypothesized that the classification system of the International Cartilage Repair Society (ICRS) will allow for improved assessment of lesion grade and stability in OCD.

MATERIALS AND METHODS

Routine MRI studies of 46 consecutive patients with arthroscopically proven OCD lesions (mean age: 23.7 years; 26 male, 16 female) were assessed by three radiologists who were blinded to arthroscopic results. Arthroscopic images were evaluated by two orthopedic surgeons in consensus. The OCD criteria of the ICRS were applied to arthroscopy and imaging interpretations. Inter-rater correlation statistics and accuracy of magnetic resonance (MR) grading with respect to arthroscopy were determined.

RESULTS

Only 56% of the available MR reports assigned a label of stable or unstable to the lesion description. Of these, 58% of the lesions were deemed unstable and 42% were stable. Accuracy was 53% when reports addressed stability. Utilizing the ICRS classification system, for all three readers combined, the respective sensitivity, specificity, and accuracy of MR imaging to determine lesion stability were 70%, 81%, and 76%. When compared to the original MRI report, the overall accuracy increased from 53% to 76% when readers were given the specific criteria of the OCD ICRS classification. However, inter-reader variability remained high, with Krippendorf's alpha ranging from 0.48 to 0.57.

CONCLUSIONS

In this paper, we utilize arthroscopy as the gold standard to determine if MRI can predict OCD lesion stability, the most important information to guide patient treatment decisions. To our surprise, the analysis of the existing radiology reports that addressed stability revealed an overall accuracy in defining OCD lesion stability of about 53%. The classification system of the ICRS, created by an international multidisciplinary, multi-expert consortium, did markedly improve the accuracy, but consistency among different readers was lacking. This retrospective study on OCD reporting and classification highlights the inadequacy of existing classification schemes, and emphasizes the critical need for improved diagnostic MRI protocols in musculoskeletal radiology in order to propel it toward evidence-based medicine.

Discrepancy between morphological findings in juvenile osteochondritis dissecans (OCD): a comparison of magnetic resonance imaging (MRI) and arthroscopy

PURPOSE

The aim of this study was to assess the reliability of preoperative MRI for the staging of osteochondritis dissecans (OCD) lesions of the knee and the talus in juvenile patients, using arthroscopy as the gold standard of diagnosis.

METHODS

Sixty-three juvenile patients (range 8-16 years) with an OCD of the knee or the talus underwent arthroscopy after MRI. In 54/9 out of 63 cases, 1.5/3 T MR scanners were used. The OCD stage was classified according the staging criteria of Dipaola et al. Arthroscopic findings were compared with MRI reports in each patient.

RESULTS

From the 63 juvenile patients, MRI/arthroscopy revealed a stage I OCD in 4/19 patients, stage II in 31/22 patients, stage III in 22/9 patients and stage IV in 6/6 patients. No osteochondral pathology was evident in arthroscopy in seven out of 63 patients. The overall accuracy of preoperative MRI in staging an OCD lesion of the knee or the talus was 41.3%. In 33 out of 63 patients (52.4%), arthroscopy revealed a lower OCD stage than in the preoperative MRI grading, and in four out of 63 cases (6.4%), the intraoperative arthroscopic grading was worse than in preoperative MRI prior to surgery. The utilization of the 3 T MRI provided a correct diagnosis with 44.4%.

CONCLUSIONS

Even with today's modern MRI scanners, it is not possible to predict an accurate OCD stage in children. The children's orthopaedist should not solely rely on the MRI when it comes to the decision to further conservative or surgical treatment of a juvenile OCD, but rather should take surgical therapy in consideration within persisting symptoms despite a low OCD stage provided by MRI.

LEVEL OF EVIDENCE

III.

Quantitative susceptibility mapping detects abnormalities in cartilage canals in a goat model of preclinical osteochondritis dissecans

PURPOSE

To use quantitative susceptibility mapping (QSM) to investigate changes in cartilage canals in the distal femur of juvenile goats after their surgical transection.

METHODS

Chondronecrosis was surgically induced in the right medial femoral condyles of four 4-day-old goats. Both the operated and control knees were harvested at 2, 3, 5, and 10 weeks after the surgeries. Ex vivo MRI scans were conducted at 9.4 Tesla using T_RAFF (relaxation time along a fictitious field)-weighted fast spin echo imaging and QSM to detect areas of chondronecrosis and investigate cartilage canal abnormalities. Histological sections from these same areas stained with hematoxylin and eosin and safranin O were evaluated to assess the affected tissues.

RESULTS

Both the histological sections and the T_RAFF -weighted images of the femoral condyles demonstrated focal areas of chondronecrosis, evidenced by pyknotic chondrocyte nuclei, loss of matrix staining, and altered MR image contrast. At increasing time points after surgery, progressive changes and eventual disappearance of abnormal cartilage canals were observed in areas of chondronecrosis by using QSM.

CONCLUSION

Abnormal cartilage canals were directly visualized in areas of surgically induced chondronecrosis. Quantitative susceptibility mapping enabled investigation of the vascular changes accompanying chondronecrosis in juvenile goats. Magn Reson Med 77:1276-1283, 2017. © 2016 International Society for Magnetic Resonance in Medicine.

Proximal tibial morphology and its correlation with osteochondritis dissecans of the knee

PURPOSE

The relationship of proximal tibial morphology to the presence of femoral osteochondritis dissecans (OCD) lesions is unknown. This radiographic study tested the null hypothesis that knees with unilateral medial or lateral OCD lesions would have no difference in the slope of their medial, lateral, or posterior tibial plateau compared with unaffected knees.

METHODS

There were 72 patients with unilateral OCD lesions of the medial or lateral femoral condyle seen at our institution from 2005 to 2011. On AP and lateral radiographs of the knee, three examiners conducted independent measurements of the tibial plateau posterior slope, as well as medial and lateral slope as measured from the peak of the tibial spine to the edge of the plateau on the side of the corresponding OCD lesion. Measurements were repeated on normal contralateral and matched control knees.

RESULTS

Knees with medial femoral condyle OCD lesions had greater medial tibial slope compared with normal contralateral knees (p = 0.007) and normal controls (p < 0.04). Knees with lateral femoral condyle OCD lesions had no significant difference in lateral tibial slope compared with the contralateral knee or matched controls. Posterior slope was greater in knees with medial OCD lesions than matched controls (p = 0.007). Intraclass correlation coefficients demonstrated consistency between observers for all measurements.

CONCLUSION

An assessment of proximal tibial morphology demonstrated greater medial and posterior tibial slope in knees with medial OCD lesions compared with normal knees. The technique for measuring medial and lateral tibial slope was reliable among evaluators. The clinical relevance is that proximal tibial morphology may have a relationship with OCD lesions.

LEVEL OF EVIDENCE

III.

Long-term athletic development, part 2: barriers to success and potential solutions

The first installment of this two-part commentary reviewed existing models of long-term athletic development. However, irrespective of the model that is adopted by practitioners, existing structures within competitive youth sports in addition to the prevalence of physical inactivity in a growing number of modern-day youth may serve as potential barriers to the success of any developmental pathway. The second part of this commentary will initially highlight common issues that are likely to impede the success of long-term athletic development programs and then propose solutions that will address the negative impact of such issues.

Multiparametric MRI of Epiphyseal Cartilage Necrosis (Osteochondrosis) with Histological Validation in a Goat Model

PURPOSE

To evaluate multiple MRI parameters in a surgical model of osteochondrosis (OC) in goats.

METHODS

Focal ischemic lesions of two different sizes were induced in the epiphyseal cartilage of the medial femoral condyles of goats at 4 days of age by surgical transection of cartilage canal blood vessels. Goats were euthanized and specimens harvested 3, 4, 5, 6, 9 and 10 weeks post-op. Ex vivo MRI scans were conducted at 9.4 Tesla for mapping the T1, T2, T1ρ, adiabatic T1ρ and TRAFF relaxation times of articular cartilage, unaffected epiphyseal cartilage, and epiphyseal cartilage within the area of the induced lesion. After MRI scans, safranin O staining was conducted to validate areas of ischemic necrosis induced in the medial femoral condyles of six goats, and to allow comparison of MRI findings with the semi-quantitative proteoglycan assessment in corresponding safranin O-stained histological sections.

RESULTS

All relaxation time constants differentiated normal epiphyseal cartilage from lesions of ischemic cartilage necrosis, and the histological staining results confirmed the proteoglycan (PG) loss in the areas of ischemia. In the scanned specimens, all of the measured relaxation time constants were higher in the articular than in the normal epiphyseal cartilage, consistently allowing differentiation between these two tissues.

CONCLUSIONS

Multiparametric MRI provided a sensitive approach to discriminate between necrotic and viable epiphyseal cartilage and between articular and epiphyseal cartilage, which may be useful for diagnosing and monitoring OC lesions and, potentially, for assessing effectiveness of treatment interventions.

Osteochondritis dissecans with a large osteochondral free body in the posterolateral compartment of the knee: a case report

A large osteochondral fragment trapped in the posterolateral compartment of a knee was removed from a posteromedial portal through the trans-septal portal and fixed on an osteochondral defect of the lateral femoral condyle in a 16 year-old boy. When a free body in the posterolateral compartment is so large that enlargement of the portal site is required for removal, doing so from a posteromedial portal is safer and easier than from a posterolateral portal.