Here is an abstract of a journal article that provides information regarding the susceptibility of a partial tear to progress to a complete deficiency. I received permission to provide the below abstract but not the full article. The abstract covers all the important highlights.
Noyes FR, Mooar LA, Moorman III CT, McGinniss GH. Partial tears of the anterior cruciate ligament: Progression to complete ligament deficiency. Journal Of Bone and Joint Surgery [Br] 1989; 71-B:825-33.
ABSTRACT: In a prospective seven-year study, we treated 32 patients with partial ruptures of the anterior cruciate ligament (ACL)verified by arthroscopy. Twelve knees (38%) progressed to complete ACL deficiency with positive pivot shift tests and increased anteroposterior translation on tests with the KT-1000 arthrometer. Patients with partial ACL tears frequently had limitation for strenuous sports, while those
developing ACL deficiency had additional functional limitations involving recreational activities.
Three factors were statistically significant in predicting which partial tears would develop complete ACL deficiency: the amount of ligament tearing - one-fourth tears infrequently progressed, one-half tears progressed in 50% and three-fourth tears in 86%; a subtle increase in initial anterior translation; and the occurrence of a subsequent re-injury with giving-way.
