The association between patella alignment and morphology and knee osteoarthritis.

Objective: This study aims to quantitatively assess the relationship between the patella alignment and morphology and knee osteoarthritis (KOA), as well as the kinematics and kinetics of the knee, using gait analysis.

Methods: Eighty age-matched patients with KOA and control subjects were evaluated. Incident radiographic osteoarthritis (iROA) was identified using a Kellgren-Lawrence (KL) grade of ≥ 2. The modified Insall-Salvati ratio (Mod-ISR), patellar tilt angle (PTA), and patella index (PI) were utilized to evaluate the sagittal and transverse alignment of the patella and its morphology, respectively. Regression analyses were conducted to explore associations between patellar measurements and KOA, iROA, kinematics, and kinetics.

Results: Significant differences were observed between the control and KOA groups in terms of KL grade, patella alta, abduction angle, and reaction force to the ground (P < 0.05, respectively). Following adjustment for covariates, a significant positive association was found between patella alta and KOA (OR = 0.307, 95%CI: 0.103 to 0.918, P = 0.035). Additionally, a significant negative association was observed between PTA and abduction angle (B = -0.376, 95%CI: -0.751 to -0.002; P = 0.049). The PI exhibited a statistically significant association with log-transformed vertical ground reaction force (B = 0.002, 95%CI: 0.001 to 0.003, P = 0.002). Furthermore, adjustment for covariates did not reveal any significant correlations with other indicators (P > 0.05, respectively).

Conclusion: This study provides further evidence that proper alignment and morphology of the patella might be associated with maintaining normal biomechanical function. In addition, intervention measures targeting relevant patellar parameters, such as Mod-ISR, PTA, and PI, may positively impact KOA treatment outcomes.