Qualitative and quantitative assessments of radiographic healing of osteochondritis dissecans of the humeral capitellum

Osteochondritis dissecans of the elbow: recent evolution of pathogenesis, imaging, and treatment modalities

Background

The etiology and pathogenesis of osteochondritis dissecans (OCDs) lesions remain controversial.

Methods

This review presents the recent evolution about the healing, imaging, pathogenesis, and how to treat OCD of the capitellum in overhead athletes.

Results

Compressive and shear forces to the growing capitellum can cause subchondral separation, leading to OCD, composed of 3 layers: articular fragment, gap, and underlying bone. Subchondral separation can cause ossification arrest (stage IA), followed by cartilage degeneration (stage IB) or delayed ossification (stage IIA), occasionally leading to osteonecrosis (stage IIB) in the articular fragment. Articular cartilage fracture and gap reseparation make the articular fragment unstable. The mean tilting angle of capitellar OCD is 57.6 degrees in throwers. Anteroposterior radiography of the elbow at 45 degrees of flexion (APR45) can increase the diagnostic reliability, showing OCD healing stages, as follows: I) radiolucency, II) delayed ossification, and III) union. Coronal computed tomography and magnetic resonance imaging with an appropriate tilting angle can also increase the reliability. MRI is most useful to show the instability, although it occasionally underestimates. Sonography contributes to detection of early OCD in adolescent throwers on the field. OCD lesions in the central aspect of the capitellum can be more unstable and may not heal. Cast immobilization has a positive effect on healing for stable lesions. Arthroscopic removal provides early return to sports, although a large osteochondral defect is associated with a poor prognosis. Fragment fixation, osteochondral autograft transplantation, and their hybrid technique have provided better results.

Discussion

Further studies are needed to prevent problematic complications of capitellar OCD, such as osteoarthritis and chondrolysis.

Conservative treatment for stable osteochondritis dissecans of the elbow before epiphyseal closure: effectiveness of elbow immobilization for healing

BACKGROUND AND HYPOTHESIS

Stable lesions of osteochondritis dissecans (OCD) of the capitellum have been treated with activity restriction (AR), and the complete healing requires 1 or 2 years. Little is known about the effectiveness of elbow immobilization. We hypothesized that elbow immobilization would have positive effects on healing of stable OCD.

METHODS

The study subjects were 43 patients (mean age: 12.2 years) with 43 stable OCD lesions of the prematured elbow (mean skeletal age score: 17.1 points of 0-27 points system). The subjects were divided into 3 groups: group A, AR without elbow immobilization, 22 cases; group B, splint (mean: 8.8 weeks) followed by AR, 9 cases; and group C, cast (mean: 3.7 weeks) followed by splint (mean: 7.3 weeks) and AR, 12 cases. The mean nonoperative observation period was 17.5 months (minimum three months). On anteroposterior radiographs of the elbow at 45 degrees of flexion, 5 observers independently assessed the healing of the capitellum, and the interobserver and intraobserver reliabilities were examined. The differences in outcomes among 3 groups were also examined.

RESULTS

The interobserver and intraobserver reliabilities of the radiographic assessment were almost perfect (Cohen kappa value: 0.82 and 0.91, respectively). There were no significant differences in age, sports played, or stage of the lesion before the treatment. The proportion of patients returning to sports and the mean period required were 77% and 8.2 months in group A, 78% and 5.7 months in group B, and 83% and 4.4 months in group C, respectively. The proportion of patients showing ossification in the central aspect of the capitellum and the mean period required were 67% and 8.2 months in group A, 63% and 4.9 months in group B, and 91% and 1.9 months in group C, respectively. The proportion of patients showing complete healing and the mean period required were 41% and 16.4 months in group A, 67% and 7.0 months in group B, and 92% and 5.5 months in group C, respectively. Compared to group A, group C showed a significantly earlier return to sports (P = .034), a significantly shorter period required for ossification (P < .001), and significantly higher proportion of patients with complete healing (P = .012) within a significantly shorter period (P = .009).

CONCLUSION

Elbow immobilization had positive effects on healing and enabled both an early return to sports and complete healing. Cast immobilization is recommended as a first choice of nonoperative treatment for stable OCD lesions of the elbow before epiphyseal closure.

Staging of osteochondritis dissecans of the elbow based on pathologic progression in the partially detached articular fragment

BACKGROUND

Osteochondritis dissecans (OCD) is considered to show the following stages of pathologic progression: IA, nearly normal-cartilaginous; IB, deteriorated-cartilaginous; IIA, cartilage-ossifying; and IIB, cartilage-osteonecrotic. However, the validity of this pathologic staging for OCD has yet to be confirmed in a large number of cases.

PURPOSE

The aim of the present study was to confirm the clinical validity of the proposed pathologic staging of OCD.

METHODS

The subjects were 74 patients (mean age, 14.2 years; mean skeletal age score, 25.6 points) with capitellar OCD. Partially detached articular fragments were surgically removed and were examined histologically. The articular fragments were independently assessed by 5 observers, and the reliability of assessment was examined. The correlation between the pathologic stages and the clinical data was analyzed.

RESULTS

The reliability of the assessment among 5 observers was almost perfect. OCD stages of IA, IB, IIA, and IIB were evident in 8, 36, 10, and 20 patients, respectively. OCD-I (cartilaginous) and OCD-II (osteochondral) corresponded significantly to radiographic stage I (radiolucency) and stage II (delayed ossification), respectively. The pathologic OCD stages were significantly correlated with the clinical data, including the period from symptom onset to surgery, patient age, and the skeletal age score (P < .01).

CONCLUSION

Our results confirmed that the proposed pathologic staging of OCD corresponds to the observed clinical progression of OCD, thus validating the staging system. Our findings revealed that OCD begins with separation beneath the epiphyseal cartilage, which is programmed to be replaced with bone. When a stage IA articular fragment has remained partially detached for a prolonged period, the epiphyseal cartilage may be deteriorated and become degenerated, and subsequent ossification may not occur, as is evident in OCD-IB. In contrast, stage IA with a vascular supply through the fibrocartilaginous connection can progress to stage IIA. During the prolonged period in which the osteochondral articular fragment remains ununited, microtrauma can cause to disturb the blood supply to the bony fragment, resulting in osteonecrosis (stage IIB).