The Comparison of Knee Joint Muscles Flexibility between Women with and without Radiographic Knee Osteoarthritis

Background Approximately 60% of individuals above 50 years are affected by knee osteoarthritis (KOA). KOA is mostly assessed through radiographic evaluation, by the Kellgren and Lawrence (KL) classification system with KL Grade 0 (KLG0) indicating a definite absence of radiographic KOA (RKOA) and KLG2 presenting a definite presence of RKOA. To compare the knee joint muscles flexibility between three groups of knees with KLG0, KLG2, and KLG3 RKOA. Methods This is a descriptive cross-sectional study. Ninety-four knees with KLG0, KLG2, and KLG3 of 57 women ≥40 years were examined in the study. The flexibility of the quadriceps, hamstring, iliotibial band, adductor, and gastrocnemius muscles was compared. Result The iliotibial band flexibility in the subjects with KLG3 RKOA was lower than those with KLG2 (p <0.05), and KLG0 (P≤0.001) RKOA, with the latter two groups being statistically equivalent (P=0.075). In addition, the quadriceps muscles flexibility in the subjects with KLG3 RKOA was lower than those with KLG2 (P≤0.001), and KLG0 (P≤0.001) RKOA, with the latter two groups being statistically different (P≤0.001). No significant differences were found between groups regarding other muscles (P>0.05). Conclusion In patients with RKOA, the flexibility of the iliotibial band and quadriceps muscles may decrease as the disease progress from KLG2 to KLG3. Also, the quadriceps and iliotibial band flexibility may be lower in KLG3 compared to KLG0, with the lower likelihood of the quadriceps flexibility in KLG2 compared to KLG0. These results suggest that quadriceps and iliotibial band stretching may be potentially important components of treatment.