Severity of subchondral insufficiency knee fracture: is it associated with increasing age, femorotibial angle, and severity of meniscus extrusion?

Abstract

Aim: To evaluate the relationship between severity of subchondral insufficiency fracture of the knee (SIFK) and age, gender, knee alingment, meniscus tear, type and location, severity of meniscus extrusion, and degree of knee osteoarthritis.
 Material and Method: This retrospective study included 308 patients with SIFK seen on MRI. SIFK lesions were categorized as grade 1 to 4, with distinction between low grade (1 and 2) and high grade (3 and 4). The relationships between SIFK grade and patients' age, body mass index (BMI), femorotibial angle (FTA), meniscus tear,type and location meniscusextrusiongrade and osteoarthritis (grade 0 to grade 4) evaluated.
 Results: According to the gender, 39.3% were men and 60.7% were women. The distrubutin of the SIFK grades were respectively 42.2% grade 1, 30.8% grade 2, 22.7% grade 3 and 4.2% grade 4. FTAwas positively correlated with SIFK grade (from grade 1 to grade 4, respectively; 4.42±2.57, 5.09±2.26, 5.74±2.78 and 5.95±2.54) (p=0.002). No statistically significant difference was observed between height, weight and BMI and the degree of SIFK.The mean FTA was 4.99±2.57° in SIFK. The FTA angles showed a stastistically significance between low (4.73±2.48°) and high (5.71±2.69°)grade SIFK (p:0.003). Roc analysis showed that the FTA above 3.1° and the age above 52 year old were at risk. The mean extent of meniscal extrusion was larger in high grade SIFK (p=0.001). Multivariable logistic regression analysis showed that compared with low grade SIFK, high grade SIFK was more closely associated with age, FTA, lateral meniscus extrusion and medial meniscus tear type.
 Conclusion: High-grade SIFK lesions are associated with higher FTA and older age. In particular, patients with acute knee pain, older than 52 years of ageanda higher FTA than 3.1°, we recommend to perform knee MRI if possible.