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Femoral osteochondritis of the knee: prognostic value of the mechanical axis

View Article: PubMed Central - PubMed

ABSTRACT

Purpose: Femoral osteochondritis dissecans (OCD) is a disorder of unknown aetiology and variable prognosis that causes knee pain. In this paper, the authors study the impact of lower limb malalignment on the development and prognosis of OCD.

Methods: After anteroposterior (AP) and lateral radiograph and MRI of the knee, 53 cases of OCD were diagnosed. All patients were studied by standing full-length AP radiograph of the lower extremities in order to analyse the relationship between the femorotibial and mechanical axis and the location and stability of the osteochondritis.

Results: The OCD lesion was located in the medial condyle (zone 2) in 75.5% of cases (40 cases). The lateral condyle was affected in 24.5% of cases (zone 4 in nine cases and zone 5 in four cases). The femorotibial angle (anatomical axis) was normally aligned in 68% of cases. A valgus deformity was observed in 9.5% of cases and a varus deformity in 22.5%. The mechanical axis of the limb appeared normal in only 32% of cases, with medial deviation in 53%, and lateral deviation in 15% of cases. When the OCD lesion was located in the medial condyle (40 cases), the mechanical axis also crossed the knee through the medial zone in 28 cases. When the OCD lesion was located in the lateral condyle (13 cases), the mechanical axis crossed the knee through zones 1 or 2 in four cases. In stable OCD, the mechanical axis and location of the lesion coincided in 19 of 36 cases (52%), compared with 16 of 17 cases (94%) in unstable OCD.

Conclusions: There is a high correlation between OCD location and lower limb mechanical axis deviation. The convergence of the mechanical axis with the location of the OCD lesion may be considered an associated factor in fragment instability. This convergence is more common in unstable OCD.

No MeSH data available.


Related in: MedlinePlus

(a) Radiograph and MRI of a 16-year-old boy with unstable medial condyle osteochondritis dissecans (OCD) with an intra-articular free body. (b) Anteroposterior stand-up radiograph of lower limbs showing convergence between the OCD lesion and the mechanical axis of the left limb.
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Figure 2: (a) Radiograph and MRI of a 16-year-old boy with unstable medial condyle osteochondritis dissecans (OCD) with an intra-articular free body. (b) Anteroposterior stand-up radiograph of lower limbs showing convergence between the OCD lesion and the mechanical axis of the left limb.

Mentions: This fact may be closely connected to the stability of the lesion, since, in the unstable forms, the mechanical axis converged with the OCD lesion in 94% of cases, while in the stable forms this convergence was present in only 53% of cases (p > 0.01) (Fig. 2). The mean that age of the patients with stable lesions (11.6 years) was significantly lower than for unstable forms (18.4 years) (p < 0.001).


Femoral osteochondritis of the knee: prognostic value of the mechanical axis
(a) Radiograph and MRI of a 16-year-old boy with unstable medial condyle osteochondritis dissecans (OCD) with an intra-articular free body. (b) Anteroposterior stand-up radiograph of lower limbs showing convergence between the OCD lesion and the mechanical axis of the left limb.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC5382330&req=5

Figure 2: (a) Radiograph and MRI of a 16-year-old boy with unstable medial condyle osteochondritis dissecans (OCD) with an intra-articular free body. (b) Anteroposterior stand-up radiograph of lower limbs showing convergence between the OCD lesion and the mechanical axis of the left limb.
Mentions: This fact may be closely connected to the stability of the lesion, since, in the unstable forms, the mechanical axis converged with the OCD lesion in 94% of cases, while in the stable forms this convergence was present in only 53% of cases (p > 0.01) (Fig. 2). The mean that age of the patients with stable lesions (11.6 years) was significantly lower than for unstable forms (18.4 years) (p < 0.001).

View Article: PubMed Central - PubMed

ABSTRACT

Purpose: Femoral osteochondritis dissecans (OCD) is a disorder of unknown aetiology and variable prognosis that causes knee pain. In this paper, the authors study the impact of lower limb malalignment on the development and prognosis of OCD.

Methods: After anteroposterior (AP) and lateral radiograph and MRI of the knee, 53 cases of OCD were diagnosed. All patients were studied by standing full-length AP radiograph of the lower extremities in order to analyse the relationship between the femorotibial and mechanical axis and the location and stability of the osteochondritis.

Results: The OCD lesion was located in the medial condyle (zone 2) in 75.5% of cases (40 cases). The lateral condyle was affected in 24.5% of cases (zone 4 in nine cases and zone 5 in four cases). The femorotibial angle (anatomical axis) was normally aligned in 68% of cases. A valgus deformity was observed in 9.5% of cases and a varus deformity in 22.5%. The mechanical axis of the limb appeared normal in only 32% of cases, with medial deviation in 53%, and lateral deviation in 15% of cases. When the OCD lesion was located in the medial condyle (40 cases), the mechanical axis also crossed the knee through the medial zone in 28 cases. When the OCD lesion was located in the lateral condyle (13 cases), the mechanical axis crossed the knee through zones 1 or 2 in four cases. In stable OCD, the mechanical axis and location of the lesion coincided in 19 of 36 cases (52%), compared with 16 of 17 cases (94%) in unstable OCD.

Conclusions: There is a high correlation between OCD location and lower limb mechanical axis deviation. The convergence of the mechanical axis with the location of the OCD lesion may be considered an associated factor in fragment instability. This convergence is more common in unstable OCD.

No MeSH data available.


Related in: MedlinePlus