Morpho-Functional Characterization and Proposal for Normative Reference Values of Static Lower Limb Alignment in Italian Amateur Basketball Players: An Observational Cross-Sectional Study Using the Knee Rotation Measurer (KRM®)

Basketball involves high-intensity biomechanical loads that induce specific postural adaptations. In order to identify injury risk factors, establishing normative values for static knee alignment is crucial, yet radiographic screening in healthy populations is ethically limited. This observational study aimed to define the reference values for static knee alignment in a large cohort of amateur basketball players using the Knee Rotation Measurer (KRM®) and to investigate the non-linear nature of morpho-functional adaptations. A cross-sectional study was conducted on 1150 amateur basketball players (590 males, 560 females; age 18–45 years), recruited from Italian leagues targeting a balanced geographical distribution. Static alignment was assessed using the KRM® in a closed bipodal stance. Results revealed a universal tendency toward internal knee rotation (~20°), which was statistically independent of foot posture (p > 0.05). Significant sexual dimorphism was found in alignment variance: while mean right and left knee valgus values were similar in both sexes (p = 0.79), males exhibited significantly higher variance compared to female (12.53 vs. 9.36 cm2) and a dominant tendency toward knee varus (p < 0.001). In conclusion, amateur basketball players present a distinct morpho-functional profile characterized by a universal tendency toward internal knee rotation, which is statistically independent of foot posture. Furthermore, significant sexual dimorphism in morphological variance and sagittal alignment highlights distinct gender-specific postural adaptations in this population.