[Non-traumatic osteochondral lesions of the knee joint during growth : Juvenile osteochondritis dissecans (JOCD) of the knee]. / Nichttraumatische osteochondrale Läsionen des Kniegelenkes im Wachstumsalter : Juvenile Osteochondrosis dissecans (JOCD) des Kniegelenkes.

BACKGROUND: Juvenile osteochondritis dissecans of the knee joint is the most common osteochondral lesion during growth, usually occurring between the 10th and 14th year of age. PATHOGENESIS: Repetitive microtraumata lead to a subchondral osseus lesion, which is commonly located at the medial aspect of the femoral condyle. Sport activities are considered to be the main cause, although genetic and hereditary factors as well as vitamin D3 deficiency also play a role. Current classification systems distinguish between stable and unstable osteochondral lesions, which is decisive for further treatment. TREATMENT: Stable lesions may heal through conservative treatment by avoiding weight bearing and sport. Unstable lesions, on the other hand, can lead to a complete defect of the joint surface with the formation of a free joint body. In such cases, various surgical techniques aim at reconstructing the surface of the joint, in order to reduce the risk of secondary arthritis.

Current concepts: pathology in the overhead athlete's lateral elbow.

The lateral elbow is subjected to increasing compressive force in response to repetitive valgus stress. Alterations or deficiencies in overhead mechanics and the kinetic chain may predispose an athlete to injury. Evaluation includes a focused elbow physical examination and imaging, supplemented by a robust screening of core strength, balance, and mechanics of the kinetic chain. Treatment of osteochondritis dissecans, a common lateral elbow pathology, varies based on stability of the lesion, with variable, but often positive outcomes. Proper pitching mechanics, kinetic chain integrity, and workload management provide potential opportunities for prevention.

Physician preferences in diagnostics and treatment of juvenile osteochondritis dissecans are diverse across the knee, ankle and elbow: an ESSKA survey.

PURPOSE: To investigate the current preferences regarding the work-up and treatment choices of juvenile osteochondritis dissecans (JOCD) of the knee, ankle and elbow among orthopaedic surgeons. METHODS: An international survey was set up for all European Society of Sports Traumatology, Knee Surgery and Arthroscopy (ESSKA) members, which assessed various questions on diagnosis and treatment of JOCD of different joints. Respondents answered questions for one or more joints, based on their expertise. Proportions of answers were calculated and compared between joints. Consensus was defined as more than 75% agreement on an item; disagreement was defined as less than 25% agreement. RESULTS: Fifty physicians responded to the survey, of whom forty-two filled out the questions on the knee, fourteen on the ankle and nine on the elbow. Plain radiography and MRI were the most used imaging modalities for the assessment and follow-up of JOCD in the knee and ankle, but not for the elbow. MRI was also the preferred method to assess the stability of a lesion in the knee and ankle. There was universal agreement on activity and/or sports restriction as the non-operative treatment of choice for JOCD. Size, stability and physeal closure were the most important prognostic factors in determining the operative technique for the elbow. For the knee, these factors were size and stability and for the ankle, these were size and location. CONCLUSION: Activity and/or sports restriction was the non-operative treatment of choice. Furthermore, plain radiography and MRI were the preferred imaging modalities for the knee and ankle, but not for the elbow. For determining the operative technique, physicians agreed that the size of the lesion is an important prognostic factor in all joints. These findings help us understand how juvenile osteochondritis dissecans is treated in current practice and may provide opportunities for improvement. LEVEL OF EVIDENCE: Level V.

Patient-Specific iPSC-Derived Models Link Aberrant Endoplasmic Reticulum Stress Sensing and Response to Juvenile Osteochondritis Dissecans Etiology.

Juvenile osteochondritis dissecans (JOCD) is a pediatric disease, which begins with an osteonecrotic lesion in the secondary ossification center which, over time, results in the separation of the necrotic fragment from the parent bone. JOCD predisposes to early-onset osteoarthritis. However, the knowledge gap in JOCD pathomechanisms severely limits current therapeutic strategies. To elucidate its etiology, we conducted a study with induced pluripotent stem cells (iPSCs) from JOCD and control patients. iPSCs from skin biopsies were differentiated to iMSCs (iPSC-derived mesenchymal stromal cells) and subjected to chondrogenic and endochondral ossification, and endoplasmic reticulum (ER)-stress induction assays. Our study, using 3 JOCD donors, showed that JOCD cells have lower chondrogenic capability and their endochondral ossification process differs from control cells; yet, JOCD- and control-cells accomplish osteogenesis of similar quality. Our findings show that endoplasmic reticulum stress sensing and response mechanisms in JOCD cells, which partially regulate chondrocyte and osteoblast differentiation, are related to these differences. We suggest that JOCD cells are more sensitive to ER stress than control cells, and in pathological microenvironments, such as microtrauma and micro-ischemia, JOCD pathogenesis pathways may be initiated. This study is the first, to the best of our knowledge, to realize the important role that resident cells and their differentiating counterparts play in JOCD and to put forth a novel etiological hypothesis that seeks to consolidate and explain previously postulated hypotheses. Furthermore, our results establish well-characterized JOCD-specific iPSC-derived in vitro models and identified potential targets which could be used to improve diagnostic tools and therapeutic strategies in JOCD.

Detection of fragment migration into the biceps tendon sheath originating from a humeral osteochondrosis lesion - A case report and review of the literature.

The purpose of this report is to demonstrate that radiographic evaluation of the canine shoulder joint alone is not sensitive enough to detect migrated osteochondral fragments within the biceps tendon sheath, as a sequela to osteochondrosis dissecans of the caudal humeral head. A 6-months-old, male, 35 kg Hovawart was referred due to chronic intermittent lameness on the left forelimb. Survey radiographs revealed a semilunar radiolucency surrounded by a moderately sclerotic rim at the caudal aspect of the left humeral head, referred to as osteochondrosis dissecans. However, only computed tomography combined with ultrasonography could clearly confirm a dislodged osteochondral fragment within the left biceps tendon sheath and a consequent tenosynovitis. Arthroscopic treatment on the clinically affected left forelimb followed by an additional approach over the left biceps tendon sheath to remove the migrated fragment resulted in a complete remission of the lameness until the last follow-up one year after surgery. In our opinion, computed tomography should be applied in the medical work up of canine shoulder osteochondrosis (OC) as standard. Combined with ultrasonography, it can further aid in complete evaluation of the shoulder joint and reliable exclusion of displaced osteochondral fragments, which might also be missed during arthroscopy when located too far distally.

[Avascular necrosis of the capitellum humeri without any known trauma].

In this case report, a six-year-old boy presented with an extension defect of the elbow. There was no known trauma or sports in the patient's prior history. He was diagnosed with Panner's disease. This disease usually occurs in relation to trauma or repetitive microtrauma as seen in sports. Panner's disease resembles osteochondritis dissecans, and correct differentiation between the two have therapeutical and prognostic values. Conservative regiment and follow-ups are recommended.

Validation of a Novel Magnetic Resonance Imaging Classification for Osteochondritis Dissecans of the Knee.

BACKGROUND: The novel Kocher classification is a 3-group magnetic resonance imaging (MRI) classification system for osteochondritis dissecans (OCD) of the knee that was shown to have comparable reliability to that of the established 5-group Hefti classification. The purpose of this study was to evaluate the validity and clinical utility of this simplified system as an alternative to the Hefti classification. METHODS: Demographic data and arthroscopic findings were retrospectively collected from medical and surgical records of 144 consecutive knees in children with arthroscopically diagnosed knee OCD. OCD lesions on preoperative MRIs and surgical reports (serving as the reference standard) were assessed by independent raters and assigned both a Kocher and Hefti classification. Agreement between MRI classification and arthroscopic findings for both systems was assessed using weighted kappa (kw) coefficients. Validation, accuracy, sensitivity, and specificity were measured by comparing a dichotomized Kocher classification for MRI and arthroscopy, and by estimating Cohen kappa (kc) coefficients. Agreement between arthroscopic findings and treatment type was measured using the Spearman correlation coefficient. RESULTS: Inter-rater reliability between the 2 MRI raters was substantial for the Kocher classification [ka=0.66; 95% confidence interval (CI)=0.56-0.75] and moderate for the Hefti classification (ka=0.57; 95% CI=0.47-0.67). There was no difference detected in the agreement statistics for Kocher versus Hefti classifications (P=0.89). Binary agreement using dichotomized Kocher classifications was worse than the 3-group category classification. When dichotomized, combining Kocher grades 1 and 2 demonstrated moderate agreement (kc=0.41; 95% CI=0.25-0.58), and combining grades 2 and 3 demonstrated fair agreement (kc=0.34; 95% CI=0.21-0.48). There was a strong correlation between arthroscopy-based finding and treatment category for both the Kocher classification (r=0.85; 95% CI=0.80-0.89) and the Hefti classification (r=0.82; 95% CI=0.75-0.86). CONCLUSION: The validity and clinical utility of the newer 3-group Kocher classification for knee OCD is comparable to that of the well-established 5-group Hefti classification. Both systems help determine lesion stability and characteristics on MRI, which correlate closely to arthroscopic findings. This simplified classification system, with less uncertainty, provides a foundation for further outcomes research to develop an evidence-based algorithm for effective surgical management of OCD lesions of the knee. LEVEL OF EVIDENCE: Level II-diagnostic study.

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. ➤: 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.

Internal fixation for osteochondritis dissecans lesions of the knee in patients with physeal closure.

OBJECTIVE: The aim of this study was to present mid-term functional and radiological outcomes of patients with physeal closure who underwent arthroscopic or open internal fixation with headless cannulated compressive screws due to unstable Osteochondritis Dissecans (OCD) lesions of the knee. METHODS: With a diagnosis of unstable OCD of the knee, ten consecutive patients (seven male, three female) with physeal closure (mean age: 23 years; range: 17-40), underwent arthroscopic or open internal fixation with headless cannulated compressive screws. The patients were retrospectively reviewed based on functional and radiological data, with a mean follow-up of 42 months (range: 27-61). The average size of the defects was 4.2 cm2 with a range from 1.7 to 8 cm2 . The study protocol consisted of the Range of Motion (ROM), Tegner-Lysholm Score, Modified Cincinnati Rating System Questionnaire, Short Form-12 (SF-12) in addition to the plain radiograph and Computed Tomography (CT). Any development of arthrosis was assessed at the final follow-up according to the Internation Knee Documention Committee score (IKDC). RESULTS: At the final follow-up, control plain radiographs and CT showed complete union of the fragments in nine patients; however, CT imaging illustrated nonunion of the fragment in one patient. The main Tegner-Lysholm Score increased from 59 (range: 11-63) preoperatively to 97 (range: 88-100) at the final follow-up. Modified Cincinnati Rating System Questionnaire and IKDC score were 97 (range: 93-100) and 96 (range: 92-100), respectively, at the final follow-up. In addition, in terms of SF-12, the mean physical component score was 47.5 (range: 42-49), and the mean mental component score was 57.25 (range: 48-63). CONCLUSION: In patients with physeal closure, internal fixation using cannulated compressive screws may be an influential procedure for the OCD lesions of the knee ranging in size from medium to large. LEVEL OF EVIDENCE: Level IV, Therapeutic Study.

Osteochondritis dissecans of the patella: a case-report in a juvenile football player.

Osteochondritis dissecans (OCD) lesions are a rare cause of joint pain. Most often they occur in the knee, but they can occur in elbow or ankle too. They have a predilection for the immature skeleton and are most commonly seen in male sex, athletically active young children and adolescents.Sport-specific risk factors by anatomic region include sports associated with high frequencies of knee or ankle injuries (e.g., football, basketball) and for the elbow, the overhead throwing athlete (e.g., baseball pitcher) or gymnast.In the knee, they are most commonly seen in the femoral condyles of the knee. OCD of the patella is a rare condition. There are a few reports of it.We present a case of 14-year-old-male patient, football player, with osteochondritis dissecans of the patella (OCP). The clinical presentation, radiographic and MRI findings, treatment and return to player are discussed.