The healing potential of stable juvenile osteochondritis dissecans knee lesions

Abstract

Background: The purpose of the present study was to determine if patient age, lesion size, lesion location, presenting knee symptoms, and sex predict the healing status after six months of a standard protocol of nonoperative treatment for stable juvenile osteochondritis dissecans of the knee.

Methods: Forty-two skeletally immature patients (forty-seven knees) who presented with a stable osteochondritis dissecans lesion were included in the present study. All patients were managed with temporary immobilization followed by knee bracing and activity restriction. The primary outcome measure of progressive lesion reossification was determined from serial radiographs every six weeks, for up to six months of nonoperative treatment. A multivariable logistic regression model was used to determine potential predictors of healing status from the listed independent variables.

Results: After six months of nonoperative treatment, sixteen (34%) of forty-seven stable lesions had failed to progress toward healing. The mean surface area (and standard deviation) of the lesions that showed progression toward healing (208.7 +/- 135.4 mm(2)) was significantly smaller than that of the lesions that failed to show progression toward healing (288.0 +/- 102.6 mm(2)) (p = 0.05). A logistic regression model that included patient age, normalized lesion size (relative to the femoral condyle), and presenting symptoms (giving-way, swelling, locking, or clicking) was predictive of healing status. Age was not a significant contributor to the predictive model (p = 0.25).

Conclusions: In two-thirds of immature patients, six months of nonoperative treatment that includes activity modification and immobilization results in progressive healing of stable osteochondritis dissecans lesions. Lesions with an increased size and associated swelling and/or mechanical symptoms at presentation are less likely to heal.

Fig. 1

A through D: Magnetic resonance images showing a “small” juvenile osteochondritis dissecans lesion. After six months of nonoperative treatment, this lesion demonstrated progression toward healing (a “healed” outcome). A and C: Sagittal proton-density images showing the length measurement of the lesion (A) and the length measurement of the condyle (C). B and D: Coronal T1-weighted images showing the width measurement of the lesion (B) and the width measurement of the condyle (D).

Fig. 2

A through D: Magnetic resonance images showing a “large” juvenile osteochondritis dissecans lesion. After six months of nonoperative treatment, this lesion showed no signs of healing (a “failed” outcome). A and C: Sagittal proton-density images with fat saturation showing the length measurement of the lesion (A) and the length measurement of the condyle (C). B and D: Coronal T1-weighted images showing the width measurement of the lesion (B) and the width measurement of the condyle (D).

Fig. 3

A nomogram developed from the regression analysis can be used to predict outcome on the basis of normalized width, normalized length, and symptoms. To use the nomogram, one should place a straight edge vertically so that it touches the designated variable on the axis for each predictor and then should record the value that each of the three predictors provides on the “points” axis at the top of the diagram. All of the recorded “points” are then summed, and this value is located on the “total points” line with a straight edge. A vertical line drawn down from the “total points” line to the “probability of healed” line will identify the probability that the patient will demonstrate healing or progression toward healing after six months of conservative treatment based on the utilized predictive variables.

Fig. 4

Example of a representative patient's calculated probability of achieving healed status with use of our nomogram, which is based on the normalized length of the lesion, the normalized width of the lesion, and reported symptoms. The patient did not achieve healed status after six weeks of nonoperative treatment.