A radiographic analysis of alignment in 966 lower extremities with knee pain and its association with osteoarthritis in Indian population

Purpose

This study aimed to investigate the alignment based on deformity in knees affected by osteoarthritis (OA) at different stages and evaluate its association with OA.

Material and methods

The following radiological parameters were measured from weight bearing long leg radiographs of 966 legs in the Indian subjects via a morphometric software (Matlab R2009a) (1)Hip-Knee-Ankle angle (HKAA), (2) Femoral bowing, (3) Tibial Bowing, (4) Condylar Plateau angle (CPA). The knees were classified according to the Kellegren and Lawrence grading and these parameters were evaluated with OA for its association using appropriate statistical tests.

Results

The mean HKAA angle was 174.5° ±6.5°, 65.8% of the limbs were in found to be in varus (<177°) and 3.8% in valgus (>183°). The mean femoral and tibial bowing was −1.19 ± 4.95° and −1.54 ± 3.58° respectively. 55.8% of femorae and 41.4% of the tibia were observed to have varus bowing while 24.12% of femorae and 12.11% the tibia were observed to have valgus bowing. An increase in odds of disease severity was observed with femoral and tibial bowing >2°. With an increase in the grades of OA a significant increase in the lateral bow of both femur and tibia was observed. The mean condylar plateau angle was observed to be −2.53° ±7.9°. Positive association was seen between the varus CPA, HKA and OA (p < 0.01).

Conclusion

This study describes the various radiological parameters in Indian patients at different grades of OA and might elucidate the role of these factors in OA initiation and progression.