Medial Metaphyseal Beak Angle as a Predictor for Langenskiöld Stage II of Blount's Disease.

OBJECTIVE: To determine the medial metaphyseal beak (MMB) cut-off angle predicting Langenskiöld stage II of Blount's disease and to study the intra-observer and inter-observer reliabilities of angle measurements and the influence of the experience level of observers. METHODS: A retrospective study was conducted on children aged 2-4 years from January 2000 to December 2017. Children were identified through a computer-based search. Children with Langenskiöld stage II of Blount's disease who had been initially evaluated at our institution were categorized into Blount group and children who were diagnosed with physiologic bowing were categorized into control group. Data on the patients' ages, genders, and affected sides were collected. The MMB angles were measured on standing anteroposterior radiographs of the knees. The angle was formed between one line drawn parallel to the medial cortex of the proximal tibia, and a second line running from the intersection of the first line with the proximal tibial metaphysis through to the most distal point of the MMB. Measurements were independently performed by six observers. All observers repeated the measurements 2 weeks after they were first done. RESULTS: There were 148 legs from 79 children (48 males and 31 females) with an average age of 28.6 months. The average MMB angle of the Blount group was 128.52° ± 5.38° (P-value <0.001) and of the control group was 114.45° ± 4.89°. The average femorotibial angle of the Blount group was 15.48° ± 6.81° (P-value <0.001) and of the control group was 7.71° ± 7.94°. The receiver operating characteristic curve showed that an MMB angle >122° (sensitivity 92.7%; specificity 97.0%) was associated with Langenskiöld stage II. The intraclass correlation coefficient of the intra-observer reliability ranged from 0.93-0.97, and the inter-observer reliability was 0.93. CONCLUSIONS: By using anteroposterior (AP) radiographs of the knee, the MMB angle is a potential radiographic parameter to distinguish between Langenskiöld stage II of Blount's disease and physiologic bowed legs, with an MMB angle >122° predicting Langenskiöld stage II.

Assessment of the reliability and reproducibility of the Langenskiöld classification in Blount's disease.

The Langenskiöld classification is the most commonly utilized classification system for the radiological features of Blount's disease. Although there is only a single study found on the interobserver variability and none found on the intraobserver variability, it is commonly used for prognostication and guiding management decisions. The aim of this study was to determine the reliability and reproducibility of the Langenskiöld classification. A retrospective review of radiographs was done of patients treated for infantile and juvenile Blount's disease at Chris Hani Baragwanath Academic Hospital from 2006 to 2016. There were 70 radiographs of acceptable quality, which were reviewed and staged on two occasions according to the Langenskiöld classification by three orthopaedic consultants and three orthopaedic surgery senior residents. Pearson correlation coefficients, percentage agreements, and κ statistics were used to evaluate both the reliability and reproducibility. Of the 70 images staged, only two (2.9%) were staged the same by all six observers, and 20 (28.6%) images differed by a single stage. The consultants had 17 (24.3%) images staged the same whereas the residents had 12 (17.1%) images staged the same. The overall κ for all six observers showed a fair agreement of 0.24. Again, the consultants had a higher κ-value compared to residents of 0.25 and 0.24, respectively. The reproducibility amongst all observers was fair with a κ-value of 0.38. The consultants had a higher mean score of 0.48 compared to 0.26 for the residents. There was only a fair overall reliability and reproducibility amongst the six observers. We recommend the Langenskiöld classification be used with caution when being used for prognostication and management planning as well as when interpreting any research relying on this classification. Level of evidence: Level III, diagnostic study.

Recurrence After Surgical Intervention for Infantile Tibia Vara: Assessment of a New Modified Classification.

BACKGROUND: To propose a modified classification of infantile tibia vara based on the morphology of the metaphyseal/epiphyseal tibial slope that better correlates with treatment outcomes than the traditional Langenskiold classification. METHODS: We performed a retrospective review of 82 patients and 115 limbs that underwent surgery for infantile tibia vara over a 22-year period (1990 to 2012) at a single institution. A modified Langenskiold classification was applied to all patients preoperatively and the outcomes were assessed. The modified system created a 3-stage classification (types A, B, and C): type A has a partially lucent medial metaphyseal defect, with or without "beaking"; type B deformity has downward-sloping curvature of the lateral and inferior rim of a completely lucent metaphyseal defect, which then has an upslope at the medial rim, resembling a ski-jump, with no epiphyseal downward slope; type C has vertical, downsloping deformity of both the epiphysis and metaphysis, with no upward curvature projecting medially at the inferior extent, while the epiphysis slopes downward into the metaphyseal defect. RESULTS: Sixty-seven limbs did not develop recurrence following corrective osteotomy, whereas 48 limbs required at least 1 repeat surgery for recurrent deformity. Preoperative mechanical axis deviation, medial proximal tibial angle, lateral distal tibial angle, and body mass index did not differ significantly between those with recurrence and those with without. Mean age at surgery was significantly different for those who developed recurrence compared with those who did not. Patients without recurrence were 4.3 years of age (range, 2.4 to 10.3 y) compared with 6.2 years of age (range, 2.9 to 10.1 y) for those who recurred (P<0.01). Of patients who developed recurrent deformity, there were significantly more patients with type C changes (71.7%, P<0.01) then either type A (22.5%) or type B (20.7%). High rates of recurrence were seen for both Langenskiold stage III (50%) and stage IV (69.6%). CONCLUSIONS: Consistent with prior studies, age 5 seems to be a critical transition in the risk for recurrent deformity after tibial osteotomy. Extreme vertical sloping of the medial metaphyseal defect, as in some classic Langenskiold III lesions and more precisely described by type C in a newer, modified classification, carries a poor prognosis for successful correction by high tibial osteotomy alone or in combination with epiphysiolysis. LEVEL OF EVIDENCE: Level II.

Blount disease.

Blount disease is an asymmetrical disorder of proximal tibial growth that produces a three-dimensional deformity. Tibia vara is the main component of the deformity. Blount disease exists as two clinical variants, infantile or early-onset, and adolescent or late-onset, defined based on whether the first manifestations develop before or after 10 years of age. The pathophysiological mechanisms are unclear. In the Americas and Caribbean, Blount disease chiefly affects black obese children. Without treatment, the prognosis is often severe, particularly in the infantile form due to the development of medial tibial epiphysiodesis at about 6 to 8 years of age. In other parts of the world, the associations with black ethnicity and obesity are less obvious and the prognosis is often less severe. A consensus exists about the optimal treatment in two situations: before 4 years of age, progressive Blount disease should be corrected, preferably by a simple osteotomy; and once medial tibial epiphysiodesis has developed, both a complementary epiphysiodesis and gradual external fixator correction of the other alignment abnormalities, rotational deformity, and limb length are required. After 4 years of age, the outcome in the individual patient is difficult to predict. Magnetic resonance imaging supplies information on the morphology and vascularisation of the growth regions, thereby helping to guide treatment decisions. In the adolescent form, morbid obesity limits the treatment options. Untreated Blount disease in adults is rarely encountered. A more common occurrence is the presence of residual abnormalities at skeletal maturity in patients treated for Blount disease in childhood. Premature osteoarthritis may develop. In this situation, osteotomy may delay the need for total knee arthroplasty.

Problems and pointers in osteochondrosis: Twenty years on.

Twenty years ago a supplement of Equine Veterinary Journal was devoted to equine osteochondrosis (OC) and recognised the importance of this developmental disease to the equine industry. In the accompanying editorial several controversial issues were identified and a number of areas for further research were highlighted. Today, equine OC is still a major clinical problem, but the on-going research has resulted in much improved knowledge and understanding of this highly complicated disease. There is still conflicting evidence on the prevalence of OC due to the dynamic character of the condition, widely varying definitions in the literature, and the range of joints affected. Nevertheless there is now convincing evidence that early vascular damage, leading to chondronecrosis, is the major mechanism of onset. The aetiological factors that determine whether a horse will develop clinical signs of OC remain obscure and the complex nature of OC and its multi-factorial character has been clearly demonstrated by genetic studies. These have shown a multitude of loci on a variety of chromosomes linked to osteochondrotic phenotypes, depending on the type of manifestation of OC, the joint involved and the breed. The controversy surrounding the possible key role of copper in the pathogenesis of OC in the early 1990s has evolved into a more limited contribution to repair thus making it just one of the many environmental factors that may have an effect on the occurrence of OC, but not a decisive one. The semantic debate concerning the most appropriate nomenclature seems to have crystallised into a consensus on terminology at three levels: OC or osteochondritis dissecans (OCD) for the disturbance in the process of endochondral ossification, juvenile ostechondral conditions (JOCC) for all joint and growth plate related disorders, and developmental orthopaedic diseases (DOD) for the full range of skeletal conditions in young horses. Future progress in improved management of OC can be expected from more research on cellular and molecular processes and the influences that determine the process of endochondral ossification, the process of articular cartilage maturation, and from epidemiological studies quantifying the long-term effects of OC on health and performance.

A review of terminology for equine juvenile osteochondral conditions (JOCC) based on anatomical and functional considerations.

This manuscript describes a new classification of the various joint-related lesions that can be seen in the young, growing horse based on their anatomical and functional aetiopathogenesis. Juvenile osteochondral conditions (JOCC) is a term that brings together specific disorders according to their location in the joint and their biomechanical origin. When a biomechanical insult affects the process of endochondral ossification different types of osteochondrosis (OC) lesions may occur, including osteochondral fragmentation of the articular surface or of the periarticular margins, or the formation of juvenile subchondral bone cysts. In severe cases, osteochondral collapse of the articular surface or the epiphysis or even an entire small bone may occur. Tension on ligament attachments may cause avulsion fractures of epiphyseal (or metaphyseal) ossifying bone, which are classified as JOCC, but do not result from a disturbance of the process of endochondral ossification and are not therefore classified as a form of OC. The same applies to 'physitis' which can result from damage to the physeal growth plate.

Relationship between arthroscopic joint evaluation and the levels of Coll2-1, Coll2-1NO(2), and myeloperoxidase in the blood and synovial fluid of horses affected with osteochondrosis of the tarsocrural joint.

OBJECTIVE: To evaluate the levels of plasmatic and synovial Coll2-1, Coll2-1NO(2) and myeloperoxidase (MPO) in horses with osteochondral lesions of the tarsocrural joint and to investigate how these levels relate to arthroscopic findings of inflammation and degeneration. MATERIALS AND METHODS: Venous blood and synovial fluid samples were collected from 63 horses presented for arthroscopic removal of osteochondral fragments in the tarsocrural joint. Prior to removal of the osteochondral fragment, an exploration of the joint was performed and an inflammatory and degenerative score was determined. The blood and synovial levels of Coll2-1, Coll2-1NO(2) and MPO were also measured. The effects of the arthroscopic evaluation (inflammatory and degenerative classes) on the blood and synovial markers were evaluated using a linear model (GLM procedure), and correlations between biochemical markers in the blood and synovial fluid and the arthroscopic evaluation (inflammatory and degenerative classes) were established (Pearson's correlations). RESULTS: Significantly higher levels of Coll2-1 were detected in synovial fluid of higher degenerative classes. There was a significant correlation between the degenerative score and the synovial levels of Coll2-1 (r=0.27). According to the logistic regression model, there was a significant effect of the degenerative class on synovial levels of Coll2-1. CONCLUSIONS: Coll2-1 correlates well with the degenerative state of tarsocrural joints as evaluated by arthroscopy. This marker can therefore be classified as a burden-of-disease marker in the assessment of joint disease in horses.

Can Blount's disease heal spontaneously?

INTRODUCTION: In stage 1 of all currently accepted classifications for infantile tibia vara, the diagnosis is difficult between physiological bowing and true Blount's disease. There is no evidence of prognosis criteria for surgical treatment at this stage. PATIENT AND METHODS: We retrospectively studied a series of 26 patients born in the Indian Ocean area, presenting at stage 1 of the disease, in order to determine whether any of them were likely to heal without treatment. RESULTS: It was found that children seen at stage 1 of infantile tibia vara have a one-in-three chance of healing spontaneously. DISCUSSION: An alternative classification in three stages could then provide more suitable therapeutic indications: stage 0: possible Blount's disease (patient older than 2.5 years); stage 1: certain Blount's disease, active physis (+) (progressive varus, age >3 years, typical image with no epiphysiodesis bridging); stage 2: certain Blount's disease, inactive physis (-) (superomedial tibial bony bridge). LEVEL OF EVIDENCE: Level IV. Retrospective study.

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