Coper Classification Early After ACL Rupture Changes With Progressive Neuromuscular and Strength Training and Is Associated With 2-Year Success: Letter to the Editor

Dear Editor:

We enjoyed reading the recent article by Thoma et al ¹⁰ : it provides a refreshing picture of a different, yet evidence-based approach for the management of acute anterior cruciate ligament (ACL) tears. We are in full agreement with Thoma et al ¹⁰ and respectfully point out that some features that they focus on were made manifest by our research group over the course of the last 20 years or so.

The authors demonstrate that surgical reconstruction is not required in all patients with torn ACL, and that it is possible to return to sports activities without reconstructive surgery. As we have stated for a long while, Thoma et al posit that the main indication for surgery be the functional instability (ie, a symptom) and not the laxity (ie, a sign) produced by a torn ACL. ¹⁰ Indeed, laxity is not necessarily correlated with instability, ⁷ and the wish of patients to continue to participate in high-level, possibly pivoting sport is not in itself an indication for surgery. ⁸ It is possible to identify copers, and as some individuals who may initially be noncopers may indeed become copers after appropriate intervention, we consider surgery only after failure of a 6- to 12-week period of intensive rehabilitation with hamstring strengthening and proprioception training. We proposed this strategy in 1996, highlighting the critical role of the hamstrings to control the forward motion of the tibia in the flexed knee. ⁶

After a few years, in 2003, we further developed these concepts: we stressed that the effectiveness of early ACL reconstruction to prevent or slow down the onset of degenerative changes and osteoarthritis had not been proven. ⁵ We pointed out that the studies purporting that ACL reconstruction slows down or stops the onset of degenerative joint disease were biased, as the entry criterion was just complete tear of the ACL, not symptomatic instability (ie, what Thoma et al term “dynamic instability”). According to the “rule of thirds,” ⁹ one-third of patients with an ACL tear do badly, one-third do well, and one-third do well if they modify their activities and badly if they continue with potentially injurious activities. Hence, it may well be possible that two-thirds of included patients in studies where the indication for surgery was the tear of the ACL (and not the instability caused by such a tear) would not have needed reconstruction. In essence, this is very much what Thoma et al elegantly report.

At the time, however, other authors were strongly against the facts that we put forward, stating that performing a reconstruction only after failure of rehabilitation and the experience of giving way episodes is associated with a poor result. ⁵ Such a cohort of authors likely believe that ACL reconstruction is able to prevent knee degeneration, and only a small subset of patients, less than one-third, would not need surgery. Thus, patients with an acute ACL tear, particularly those participating in athletics or other activities that require twisting or turning, should undergo surgery as early as possible to prevent further injuries, such as meniscal tears and articular cartilage damage. Finally, they suggested that our management plan may well have been negligent, and stated that we should undertake surgical reconstruction care early after an ACL injury to provide superior results to our patients.

A decade ago, Hurd et al ⁴ reported that 42% of 345 patients with an ACL injury could be managed, in the early postinjury phase, with rehabilitation only: 72% of these “potential copers” successfully returned to preinjury sports activities in the short term. Finally, only 59% of patients who returned to a high level of sports activity decided to have an ACL reconstruction. Frobell et al, ³ in an elegant and controversial randomized controlled trial, demonstrated the effectiveness of nonoperative management comparing structured rehabilitation plus early ACL reconstruction with structured rehabilitation and optional delayed surgery. They found no significant difference in terms of function between the 2 groups at 2 years after injury, and pointed out that 61% of patients in the delayed surgery group avoided an ACL reconstruction. These results were maintained at 5 years. ²

Recently, a systematic review ¹ demonstrated that ACL reconstruction does not prevent knee osteoarthritis, although it should be acknowledged that knee osteoarthritis after an ACL injury could be consequent to the associated lesions following the index injury. Furthermore, as good results are possible with both surgical and nonsurgical management, surgery may well not be critical for return to sport. As we previously described, the improvement of knee stability is the primary goal of ACL reconstruction, and this result can be obtained with correct (neuromuscular) rehabilitation in selected patients.

In conclusion, the main indication for surgery after an ACL tear is the functional rotatory instability of the knee. However, not every patient with a torn ACL needs a reconstruction, and only some of them should be offered an early operation. Predictive factors of instability after an ACL tear should be identified, because these patients are at risk of developing secondary meniscal tears and articular cartilage lesions. In this respect, the battery of tests developed by the Delaware research group is of capital importance.

Thoma et al ¹⁰ have been courageous enough to join the brigade of authors who do not just “believe” but have shown what to believe in: following an acute tear of the ACL, early reconstruction is not the gold standard, but early functional rehabilitation likely is. For this scientifically sound proven recommendation they should be congratulated.