下骨

jié lùn bìn gǔ wài cè guān jié miàn ruǎn gǔ xià gǔ gǔ zhì zuì wéi jiān gù

结论：髌骨外侧关节面软骨下骨骨质最为坚固。

Conclusion: The optimum level of patella of the retropatellar articular surface is lateral facet.