An ACL injury can sound like an automatic ticket to surgery. For many people, especially recreational athletes with a first-time and relatively uncomplicated ACL injury, that may not be the case. Research suggests that a structured rehabilitation program can produce very good outcomes for some patients, and starting physical therapy early may improve the chances of success.
The anterior cruciate ligament, or ACL, is one of the major stabilizing ligaments of the knee. ACL injuries are common in sports that involve cutting, pivoting or sudden changes of direction, but they can also happen during everyday accidents. Because an unstable knee can be vulnerable to additional injury, early evaluation and an appropriate treatment plan are important.
What Happens If You Try Rehabilitation First?
A prospective study published in Knee Surgery & Related Research followed 85 people with MRI-confirmed, first-time acute ACL injuries.[1] The injuries came from a variety of situations. About 35% occurred during soccer, another 39% occurred during other sports, and 22% resulted from non-sporting accidents. Rather than proceeding directly to ACL reconstruction, the patients began conservative treatment. They were given a limited hinged knee brace and started progressive exercise therapy as soon as possible. Researchers then followed them for one year.
At the end of that year, 91% of the patients met the study’s criteria for successful non-surgical treatment. They demonstrated little or no abnormal knee movement on two common clinical tests used to evaluate ACL stability, the Lachman test and pivot shift test.[1] Patients were also able to return to amateur sports at the same or a slightly reduced level of activity. Even among patients who initially showed more substantial knee instability, many improved. Of those who began the study with a higher-grade positive pivot shift test, 79% improved to grade 1 or less by the one-year mark.[1]
A few patients continued to show enough instability that surgery was recommended. Interestingly, one-quarter of those patients declined surgery because they did not feel that their knees were functionally unstable.
Starting Physical Therapy Early May Matter
One of the most interesting findings involved the timing of rehabilitation. Patients who began physical therapy within two weeks of their ACL injury had the highest treatment success rate. Among those who began rehabilitation in less than two weeks, 98% achieved successful outcomes according to the study’s stability criteria.[1]
Success rates were lower when rehabilitation started later:
Less than 2 weeks: 98%
2 to 3 weeks: 82%
3 to 4 weeks: 80%
Overall, beginning rehabilitation within two weeks was associated with about a 21% greater likelihood of treatment success.[1]
That finding supports a practical message for patients. An ACL injury should be evaluated promptly, and rehabilitation may be worth beginning early when a physician or physical therapist determines that conservative treatment is appropriate.
What Does ACL Rehabilitation Involve?
ACL rehabilitation usually focuses on restoring several things the knee loses after injury.
Early treatment may address swelling, pain, range of motion and the ability to fully straighten the knee. Rehabilitation then progresses toward restoring quadriceps strength, hamstring strength, balance, coordination and control of the knee during increasingly demanding movements.
For an athlete, later rehabilitation may include running, jumping, landing, cutting and sport-specific activities.
The goal is not simply to make the knee feel better. A good rehabilitation program works toward restoring the strength and neuromuscular control needed to keep the knee stable during real-life activity.
What About Long-Term Results?
The encouraging findings are not limited to short-term studies. Ageberg and colleagues followed patients with ACL injuries who had initially been treated with rehabilitation and activity modification. At 15 years, many continued to demonstrate satisfactory neuromuscular function.[2] Another long-term study by Neuman and colleagues found that 88% of patients initially treated without ACL reconstruction had still not elected surgery 15 years later.[3]
These studies do not mean that every ACL injury should be treated without surgery. The type and severity of the tear, associated injuries, knee stability, age, activity level and athletic goals all matter. Competitive athletes in sports requiring frequent cutting and pivoting may have very different demands from someone whose primary goals are walking, working, exercising and participating in recreational sports.
Physical Therapy Can Be Part of the Decision
For many people with a first-time ACL injury, rehabilitation can serve two purposes. It can be treatment, and it can also provide useful information. As strength, swelling, motion and coordination improve, patients and their healthcare providers get a much clearer picture of how stable and functional the knee really is. Surgery can still be considered later when instability continues or when an individual’s activity demands make reconstruction appropriate.
The researchers in the 2021 study concluded that non-professional athletes with acute ACL injuries may benefit from beginning physical therapy as early as possible and evaluating the need for surgical reconstruction afterward.[1] For someone facing a new ACL injury, that can be encouraging news. There may be time to rehabilitate the knee, see how it responds and make a more informed decision about what comes next.
Sources
Park YG, Ha CW, Park YB, Na SE, Kim M, Kim TS, Chu YY. Is it worth to perform initial non-operative treatment for patients with acute ACL injury?: a prospective cohort prognostic study. Knee Surg Relat Res. 2021;33(1):11.
Ageberg E, Pettersson A, Fridén T. 15-year follow-up of neuromuscular function in patients with unilateral nonreconstructed anterior cruciate ligament injury initially treated with rehabilitation and activity modification: a longitudinal prospective study. Am J Sports Med. 2007;35(12):2109-2117.
Neuman P, Englund M, Kostogiannis I, Fridén T, Roos H, Dahlberg LE. Prevalence of tibiofemoral osteoarthritis 15 years after nonoperative treatment of anterior cruciate ligament injury: a prospective cohort study. Am J Sports Med. 2008;36(9):1717-1725.
