The anterior cruciate ligament (ACL) is one of two main stabilizing ligaments in the knee. It joins the upper leg bone with the lower leg bone. When the ACL gets torn the patient often hears a pop, and the tear will be visible on a later MRI. Surgical reconstruction of the ligament is a common treatment choice, although 2014 study in The Journal of Bone and Joint Surgery reported high rates of re-injury after knee surgery, and many athletes never were able to return to their previous level of play.

Athletes who choose surgery often are told that they will lose a year of participation in sports. Many surgeons recently have begun telling knee patients that they will be able to return to sports six to eight months after surgery. A  study in the May 2015 issue of Knee Surgery, Sports Traumatology, Arthroscopy questions the wisdom of such recommendations.

Sixty-nine patients with ACL reconstruction were asked to perform a standardized battery of one- and two-legged stability tests, counter-movement jumps, speedy jumps, plyometric jumps, and a quick-feet test. The first test battery was given just shy of six months post-surgery, and the second test battery was given about eight months post-surgery. After these tests, only 15.9 percent and 17.4 percent of the patients respectively met the criteria to “return to non-competitive sports.” The most limiting factor was an inability to hop symmetrically with the operated leg performing like the normal one.

Fewer than one in five patients in this study were ready to return to even non-competitive sports six or eight months after surgery. Why is it taking so long for patients’ safe return to sports? After ACL surgery, there’s significant atrophy in the leg, and patients are unable to sense where their knee is oriented in space (proprioception). While this is bad news for athletes who have chosen to undergo this invasive surgery—these problems also are alarming for non-athletes.

Regenerative medicine offers an alternative option to surgical reconstruction. Patients who have chosen to treat a torn knee ligament using an injection of their own stem cells experienced good results—less down time after surgery, decreased atrophy, and no loss of proprioception. In addition, they avoided the risks associated with invasive surgery.

“ACL Surgery Return to Sports: Few Ready to Play by 8 Months!” first appeared as a post on the Regenexx blog.