Medial collateral ligament injury

American Medical Association Committee on the Medical Aspects of Sports standard nomenclature of athletic injuries[2]American Medical Association, Committee on the Medical Aspects of Sports. Standard nomenclature of athletic injuries. Physical Therapy. 1969 Nov;49(11):1323. https://academic.oup.com/ptj/article-abstract/49/11/1323/4595828

MCL injuries are classified based on the amount of medial joint opening when a valgus load is applied at 20 to 30 degrees of knee flexion: [Figure caption and citation for the preceding image starts]: The abduction (valgus) stress testFrom the collection of Sanjeev Bhatia, MD; used with permission [Citation ends].

• Grade I: 0 to 5 mm of opening

• Grade II: 5 to 10 mm of opening

• Grade III: >10 mm of opening

O'Donoghue classification[1]O'Donoghue DH. An analysis of end results of surgical treatment of major injuries to the ligaments of the knee. J Bone Joint Surg. 1955 Jan;37-A(1):1-13. http://www.ncbi.nlm.nih.gov/pubmed/13233264?tool=bestpractice.com

MCL injuries are classified based on the amount of torn fibers:

• Grade I: few torn fibers, ligament is structurally intact

• Grade II: incomplete tear, no pathologic laxity

• Grade III: complete tear, pathologic laxity