Spontaneous Healing in complete ACL ruptures: results at eight-year mean follow-up

OBJECTIVES: The injured anterior cruciate ligament (ACL) has a limited healing capacity leading to persisting instability. Although several studies have reported spontaneous healing of torn ACLs, it is difficult to determine its healing potential and whether patients will be able to return to sports activities. In 2011, we published a series of 14 patients with spontaneous healing following a complete ACL rupture, the mean follow up was 30 months (range 25-36 months). The purpose of this study was to evaluate the long-term results of spontaneous healing in complete ACL ruptures in the same group of patients. METHODS: We retrospectively reviewed a cohort of 14 patients with acute ACL injury established by physical examination and MRI (proximal third in eight patients and the midligament in six). Twelve patients were male and average age at injury was 31 years (range, 23-41 years), All patients were athletically active before the injury and suffered the lesion during a sport activity. Surgery was indicated in all patients, but it was postponed for different reasons, including related labor problems, need to travel, illnesses, planned holidays, and the patient’s personal decision not to undergo surgery. Most of the patients let the injury run its course with no bracing and unspecific rehabilitation protocol. The primary outcomes of this study were rerupture rate and time between injury and surgery. RESULTS: Twelve patients out of 14 were reevaluated (86%), with a mean follow up of 8 years (3-14). Ten were men, with a mean age of 38 years (range, 25-51 years). Five patients had an ACL reconstruction during follow-up, with a mean time between injury and surgery of 5 years (range 3-14). Initial injury was located in the proximal third in two patients and in the midligament in three. CONCLUSION: Although favorable initial evolution at 30 months after a complete ACL lesion, our series show a re-rupture rate or “scar tissue” rupture of 40% at a mean follow-up of 8 years.