Can mucoid degeneration cause an mcl sprain just from walking up stairs? no twisting, just stepped up and felt knee lock. diagnosed with grade 01-02 mcl sprain with some mucoid degeneration.

Sprains: torn ligaments and tendons- are usually trauma related.

MCL is not the prob!: Mucoid degeneration of the MCL sounds like a incorrect radiologic diagnosis that is often seen on radiology MRI reports. MCL sprain is overdiagnosed on most MRIs. If you have a locking knee it may be chondral surface damage or meniscus problems. See an orthopedist.