Predictors of subsequent contralateral total knee arthroplasty in moderate-to-severe bilateral medial knee osteoarthritis per Naohisa Miyatake, Takehiko Sugita, Seiya Miyamoto, Akira Sasaki, Maeda Ikuo, Midori Miyatake, Masayuki Kamimura, Takashi Aki, Toshimi Aizawa