Case report: Osteochondritis dissecans in twins: treatment with fresh osteochondral grafts

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

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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.

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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.

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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.

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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.

Osteochondritis Dissecans of the Knee: Etiology and Pathogenetic Mechanisms. A Systematic Review

OBJECTIVE

The purpose of this manuscript is to analyze the evidence regarding etiopathogenesis of knee osteochondritis dissecans (OCD) lesions through a systematic review, so to summate the current understanding of the origin and progression of this pathologic articular processes.

DESIGN

A systematic review of the literature was performed on the PubMed and Cochrane databases on October 2017 by 2 independent authors and included all levels of evidence. This included all English language literature, pertaining specifically to etiopathology of knee OCD with exclusions for review articles and expert opinion. Of 965 identified records, 154 full-text articles were assessed for eligibility and 86 studies met the inclusion criteria.

RESULTS

According to these studies, the etiology of OCD can be of a biological or mechanical origin: 40 articles proposed a biological hypothesis, including genetic causes (27), ossification center deficit (12), and endocrine disorders (9); conversely, 52 articles supported a mechanical hypothesis, including injury/overuse (18), tibial spine impingement (5), discoid meniscus (16), and biomechanical alterations (20) as the cause of the onset of OCD. The pathogenic processes were investigated by 36 of these articles, with a focus on subchondral bone fracture and ischemia as the ultimate events leading to OCD.

CONCLUSIONS

Biological and mechanical factors are found to result in subchondral bone remodeling alterations, acting independently or more likely synergically in the progression of knee OCD. The former includes genetic causes, deficit of ossification centers and endocrine disorders; the latter, tibial spine impingement, discoid meniscus, and biomechanical alterations, together with injuries and overuse. The resultant subchondral bone ischemia and/or fracturing appears to determine the onset and progression of OCD.

LEVEL OF EVIDENCE

Systematic review of level II-IV studies, level IV.

Osteochondritis Dissecans Lesions in Family Members: Does a Positive Family History Impact Phenotypic Potency?

BACKGROUND

Although repetitive microtrauma and athletic overuse patterns are most commonly associated with osteochondritis dissecans (OCD), recent studies have identified a potential genetic predisposition for OCD. Several case series have documented family pedigrees that support autosomal-dominant inheritance, but the families in these studies were all selected as a result of unique histories that may not accurately represent OCD inheritance patterns at large. Because there has been little investigation beyond these case reports, we aimed to describe a broader, more representative pattern of OCD inheritance applicable to all affected patients.

QUESTIONS/PURPOSES

(1) What proportion of patients treated for OCD of the knee have one or more immediate and/or extended family members with a history of OCD lesions? (2) Do patients with more phenotypically potent lesions, which we defined as patients with bilateral OCD lesions or patients who have undergone multiple procedures for OCD, have a higher frequency of affected relatives than those with less potent lesions?

METHODS

This retrospective study queried patient databases, diagnosis codes (International Classification of Diseases, 9th Revision), and surgical logs at a regional, tertiary care children's hospital to identify all patients treated over a 10-year period (March 2004-March 2014) by the senior author for OCD of the knee. All patients aged 0-18 years at the time of diagnosis were included. At our institution, patients with intact lesions are treated with a trial of conservative therapy; conversely, patients with a break in the articular cartilage and/or loose fragments of bone/cartilage are treated surgically. There were no OCD-specific contraindications to surgery. This search identified 543 patients. After patient identification, a questionnaire was designed that asked for the number, age, and gender of all immediate family members and the history of OCD lesions in any family member (immediate or extended). For all positive family members, patients were further queried regarding relevant clinical details to affirm a history of OCD. Patients were contacted by mailed questionnaires and phone calls for survey completion. All 543 patients received the survey, of which 103 (19%) responded to it and were included here. Responders were approximately 1 year younger than nonresponders; there was no difference in gender distribution. A retrospective chart review was then conducted to collect demographic information, phenotypic disease severity, and treatment details. Of the 103 included patients, 20 patients (19%) with unilateral lesions were managed nonoperatively ("conservative" group), 50 patients (49%) had unilateral lesions advanced to surgery ("unilateral" group), 21 patients (20%) had bilateral lesions managed either conservatively or surgically ("bilateral" group), and 12 patients (12%) underwent multiple procedures for the same lesion ("multiple" group). Of those included, 75 patients (73%) were treated surgically. With the numbers available, there were no baseline differences among the groups in terms of gender, lesion laterality, lesion location, or number of secondary procedures at the time of the initial surgical intervention.

RESULTS

In total, 14 of 103 (14%) patients treated for OCD in this study had an immediate and/or extended family member with a history of OCD lesions. This included four of 20 (20%) patients in the conservative group, five of 50 (10%) in the unilateral group, four of 21 (19%) in the bilateral group, and one of 12 (8%) in the multiple group. With the numbers available, we did not identify a higher proportion of immediate and/or extended family members with a positive history of OCD in those patients with phenotypically potent lesions (bilateral and multiple) as compared with those with patients phenotypically less potent lesions (conservative and unilateral; five of 33 [15%] versus nine of 70 [13%]; odds ratio, 1.2; 95% confidence interval, 0.4-3.9; p = 0.751).

CONCLUSIONS

In this broad, heterogeneous cohort of pediatric patients with OCD, the proportion of patients with a positive family history of OCD was 14%, which appeared to be much higher than the reported prevalence of OCD in the general population according to prior research. Therefore, our data provide preliminary support for a familial inheritance pattern for OCD, suggesting that further clinical, biologic, and genomic investigation might help to improve our understanding of who is at highest risk for OCD and what moderating factors might influence their disease severity and risk of progression. Furthermore, our data suggest that expanded patient education and screening regarding inheritance patterns might enhance identification of potential familial disease burden and improve access to timely and appropriate treatment.

LEVEL OF EVIDENCE

Level IV, prognostic study.

Candidate Loci are Revealed by an Initial Genome-wide Association Study of Juvenile Osteochondritis Dissecans

BACKGROUND

Osteochondritis dissecans (OCD) is a condition that oftentimes causes significant knee pain in pediatric patient populations. If left untreated, OCD significantly increases the risk of developing degenerative osteoarthritis along with its associated consequences and costs. Although a genetic component has been suggested to play a role in this disorder, few studies have been carried out in order to determine the underlying genetic etiology of this relatively common complex trait. The goal of our study was to perform an initial genome-wide association study (GWAS) to uncover candidate loci associated with the pathogenesis of OCD.

METHODS

Blood samples were acquired from 2 cohorts, aged 0 to 18 years old, consisting of 209 OCD cases and 1855 population-matched controls. Agencourt Genfind DNA isolation technology was used to isolate high-quality DNA from each sample. Genotype data was then generated utilizing the Illumina Infinium BeadChip array to examine single-nucleotide polymorphisms (SNPs).

RESULTS

In an initial GWAS analysis of our cohort, where a SNP was excluded if the Hardy-Weinberg Equilibrium test P<0.0001, the minor allele frequency<5%, and the genotyping call rate<90%, we obtained our first results for OCD. Although there was no SNP strictly reaching the threshold for genome-wide significance at this early stage, multiple SNPs (35) at several loci revealed evidence of suggestive association with OCD (P<5.0×10).

CONCLUSIONS

The results from our preliminary study are encouraging. Herein we not only discuss the relevance and applicability of GWAS in studying a genetic basis for OCD, but have also identified top signals that may suggest loci involved in coordinated expression as well as a transcription factor involved in development that may be highly relevant to this trait.

CLINICAL RELEVANCE

If genetic predispositions for OCD are detected early enough in life, attempts at activity modification, counseling, and orthopaedic monitoring may successfully reduce progression of this condition, which may lead to progressive osteoarthritis in the third to fourth decade in at-risk patients.

Pediatric Knee Osteochondritis Dissecans Lesions

Osteochondritis dissecans (OCD) can cause knee pain and dysfunction in children. The etiology of OCD remains unclear; theories on causes include inflammation, ischemia, ossification abnormalities, genetic factors, and repetitive microtrauma. Most OCD lesions in skeletally immature patients will heal with nonoperative treatment. The success of nonoperative treatment decreases once patients reach skeletal maturity. The goals of surgical treatment include maintenance of articular cartilage congruity, rigid fixation of unstable fragments, and repair of osteochondral defects with cells or tissues that can adequately replace lost or deficient cartilage. Unsalvageable OCD lesions can be treated with various surgical techniques.

Bilateral osteochondrosis of the distal tibial epiphysis: a case report

Osteochondrosis is a developmental disease characterized by an alteration of endochondral ossification. Genetic causes, repetitive mechanical stresses, vascular abnormalities, hormonal imbalances, and interruption of the blood supply to the epiphyseal cartilage are all described causes of osteochondrosis and the etiology is probably multifactorial. Osteochondrosis can occur in different apophysis and epiphysis in all immature skeletons. Distal tibial epiphysis is rarely involved and most of the time unilaterally. We report on an 11-year-old female with bilateral osteochondrosis on distal tibial epiphysis. Only one other similar case has been described in the literature to date.

Identical osteochondritis dissecans lesions of the knee in sets of monozygotic twins

Osteochondritis dissecans (OCD) is a focal, idiopathic alteration of subchondral bone structure with the risk for secondary damage to adjacent articular cartilage and the development of premature osteoarthritis. The exact etiology of OCD is unknown, although repetitive microtrauma and vascular insufficiency have been previously described. A genetic predisposition has been suggested, but the existing evidence is sparse. There are multiple case reports of twins and siblings with OCD and a few large family series in the literature, promoting the theory that OCD may have a genetic component to its etiology. This article describes 2 sets of monozygotic twins presenting concurrently with OCD of their dominant knees, offering further support for a genetic component to the etiology of OCD. Interestingly, in both sets of twins, 1 was left-handed and 1 was right-handed. Both sets of twins had simultaneous presentations and clinical courses, lending support to a genetic element to OCD. The development of the OCD lesion in the dominant knee of each patient suggests an environmental influence, perhaps due to repetitive microtrauma and overuse. Recently, a genome-wide linkage study identified a prime candidate locus for OCD. However, despite the suggested association, genetic and developmental factors in the development of OCD remain relatively unstudied. The authors believe monozygotic twins provide an excellent clinical opportunity for future examination of the role of familial inheritance in the etiology of OCD.

Articular osteochondrosis: a comparison of naturally-occurring human and animal disease

BACKGROUND

Osteochondrosis (OC) is a common developmental orthopedic disease affecting both humans and animals. Despite increasing recognition of this disease among children and adolescents, its pathogenesis is incompletely understood because clinical signs are often not apparent until lesions have progressed to end-stage, and examination of cadaveric early lesions is not feasible. In contrast, both naturally-occurring and surgically-induced animal models of disease have been extensively studied, most notably in horses and swine, species in which OC is recognized to have profound health and economic implications. The potential for a translational model of human OC has not been recognized in the existing human literature.

OBJECTIVE

The purpose of this review is to highlight the similarities in signalment, predilection sites and clinical presentation of naturally-occurring OC in humans and animals and to propose a common pathogenesis for this condition across species.

STUDY DESIGN

Review.

METHODS

The published human and veterinary literature for the various manifestations of OC was reviewed. Peer-reviewed original scientific articles and species-specific review articles accessible in PubMed (US National Library of Medicine) were eligible for inclusion.

RESULTS

A broad range of similarities exists between OC affecting humans and animals, including predilection sites, clinical presentation, radiographic/MRI changes, and histological appearance of the end-stage lesion, suggesting a shared pathogenesis across species.

CONCLUSION

This proposed shared pathogenesis for OC between species implies that naturally-occurring and surgically-induced models of OC in animals may be useful in determining risk factors and for testing new diagnostic and therapeutic interventions that can be used in humans.

Three osteochondritis dissecans lesions in one knee: a case report

BACKGROUND

Osteochondritis dissecans (OCD) has been defined as a localized process in which a focus of subchondral bone and adjacent articular cartilage separates from the surrounding bone. With the knee being the most common location for OCD development and the propensity for this lesion to be found in those who participate in sports, a repetitive microtrauma hypothesis for its cause has gained favor. However, the cause of OCD remains controversial, as does the most appropriate treatment for the varying degrees of OCD lesions.

CASE DESCRIPTION

We present a unique case of three OCD lesions in one knee. The patient was a young, athletic boy who developed three separate OCD lesions in his right knee over the course of 4 years. Temporally, the OCD lesions developed first in the lateral femoral condyle, then in the medial femoral condyle, and finally in the trochlea.

LITERATURE REVIEW

Our literature review yielded a few reports of bicondylar OCD lesions. We identified no previous reports of three separate OCD lesions found in a single joint.

PURPOSES AND CLINICAL RELEVANCE

This report illustrates how a uniquely affected knee with three OCD lesions was treated in three different ways with resolution of symptoms. Each of the OCD lesions was evaluated individually and treatment for each based on the severity of the lesion from the physical examination, imaging studies, and arthroscopic findings.

Surgical management of juvenile osteochondritis dissecans of the knee

PURPOSE

Operative management of osteochondritis dissecans (OCD) in the juvenile knee is generally indicated upon failure of conservative treatment, in unstable lesions, and in lesions nearing physeal closure. We hypothesized that juvenile OCD lesions have improved clinical and radiographic outcomes with surgical treatment following failed non-surgical management, in unstable lesions, and in lesions nearing physeal closure.

METHODS

Multiple medical databases were searched for Levels I-IV evidence with specific study inclusion and exclusion criteria. Length of mean follow-up was minimum 2 years. Studies were included if an analysis of clinical outcomes following surgical treatment of juvenile OCD was performed. All surgical techniques and defect classifications were potentially inclusive.

RESULTS

Thirty studies (29 Level IV evidence) were included for analysis (783 subjects, 862 knees). Mean post-operative follow-up was 77 months. Nearly all studies within this review demonstrated significant clinical and radiographic improvements in outcomes in surgically treated juvenile OCD at short-, mid-, and long-term follow-up. Isolated excision of weight-bearing OCD lesions led to poorer clinical and radiographic results than other surgical techniques. Outcomes were significantly better with juvenile OCD versus adult OCD.

CONCLUSIONS

Surgical treatment of juvenile OCD has significantly improved clinical and radiographic outcomes at short-, mid-, and long-term follow-up. No difference in clinical or radiographic outcome was demonstrated in comparing different surgical techniques, with the exception of poorer results with isolated fragment excision.

LEVEL OF EVIDENCE

IV.

Osteochondritis dissecans of the humeral capitellum in identical twins

Osteochondritis dissecans (OCD) of the humeral capitellum is a disorder affecting mainly boys between the ages of 12 and 15 years. The exact etiology of OCD is not clear, but it is believed that repetitive trauma is the primary cause. Genetic factors are thought to play a secondary role in the pathogenesis. We present 17-year-old identical twins with similar MRI and arthroscopic findings, suggesting that genetic components are involved in the etiology of OCD of the humeral capitellum.