ACL Injuries- Surgical vs Conservative Management?

In recent years, non-operative management of ACL injuries has gained a tremendous amount of traction in the rehabilitation sphere, as several high quality studies have demonstrated the possibility of ACL injured athletes (both elite and non-elite) successfully returning to pre-injury level of sport without an ACL reconstruction (ACLR).

Additionally, our understanding of ACLs in general has evolved: where previously we thought ACLR was a means to minimise OA and further meniscal damage post ACL injury, there has been little to no difference found when comparing these outcomes between ACLR and nonsurgical management. What’s more, contrary to prior belief, several studies have shown the ACL can heal without surgical repair.

In 2003, Myklebust and colleagues followed a group of 79 elite handball players with ACL injury. 22 of these players attempted to return to pre-injury sporting level without a reconstruction, of which 82% were successful. On average, these players went on to participate in a further 4 years of competitive sport. Interestingly, of the remaining 57 players who elected to undergo an ACLR, only 58% returned to their pre-injury level of sport, and this was for an average of 3.8 years. Furthermore, 22% of this ACLR group sustained an ACL graft rupture once returned to sport. What’s more, the study found no significant difference between groups when looking at pain, episodes of instability, osteoarthritic changes, function and quality of life at 7 years post-injury.

Then, in 2010, Frobell and colleagues published the first (and, to date, only) paper of its kind comparing the outcomes of early ACLR to those of a structured rehabilitation program with the option of later ACLR if needed. Known as the KANON (Knee Anterior Cruciate Ligament Nonsurgical versus Surgical Treatment), this RCT followed 121 young, active adults with acute ACL injury. 62 subjects were assigned to the early ACLR group, and 59 to the rehabilitation plus optional delayed ACLR group. Of these 59, 36 underwent rehabilitation alone, and 23 opted to have a delayed ACLR. At 2 and 5 years post injury, the study found no significant differences between groups in regards to function, quality of life and physical activity levels. It was concluded, therefore, that in young, active adults with acute ACL tears, a strategy of rehabilitation plus early ACLR is not superior to a strategy of rehabilitation plus optional delayed ACLR.

So, the option for players to manage an ACL injury without surgical reconstruction is clearly a viable one. What are some factors that may influence the suitability of an athlete for a nonoperative management of their ACL injury?

Firstly, when looking at Frobell’s study, it’s important to acknowledge that all data was collected only on athletes who had injured their ACLs for the first time. As patients with previous ACL injury were excluded, these nonoperative pathway outcomes can’t reliably be applied to athletes on their second (or third, or fourth) ACL injury.

Secondly, age is an important consideration. In the Frobell study, only ACL injured patients between the ages of 18 and 35 were included.

Thirdly, concurrent knee injuries are an impacting factor. While the Frobell study included patients with minor to mild meniscus tears, grade 1-2 MCL/LCL/PCL injuries, and/or mild OA changes or cartilage damage, it did not include patients with complex meniscus tears, grade 3 MCL/LCL injuries, or full thickness cartilage injuries.

Finally, based on the KANON trial, psychological factors such as pre-existing preferences, beliefs, and lack of motivation towards rehabilitation were the main reasons patients elected to have an ACLR. In all groups, physical performance of quadriceps strength and hop tests were key factors of success.
In summary, nonoperative management of ACL injuries is a suitable option for some ACL injured patients. Generally speaking, patients aged over 18, who have injured their ACL for the first time, who may also have minor to moderate injuries to other parts of the knee, can be offered nonoperative ACL management with the knowledge that long term outcomes (2-5 years down the track) will likely be similar to those who have an early or delayed ACL reconstruction.

When deciding whether to undergo an ACLR, it’s important to recognise surgery is not a quick or perfect fix. In fact, further analysis of the KANON trial showed patients who received early ACLR were prognostically worse across several domains compared to those who opted for nonsurgical management or delayed surgery. Whether a patient opts for a reconstruction or a trial of conservative management, recovery will involve a graded, comprehensive, long-standing rehabilitation that involves prevention exercises maintained once returned to sport. A commitment and adherence to this process is a key predictor of recovery outcomes.

So, what does the rehab process look like for someone undergoing nonsurgical management of their ACL injury? Well, it’s very similar to that of an ACLR, with the key difference of timeframes: given there is no need to recover from surgery, these are expected to be decidedly faster in the case of conservative management. Aside from that, both rehabilitation processes follow a similar structure, with comparable criteria for progression. Management initially involves managing pain and swelling, restoring range of motion, and promoting early muscle activation. As the patient progresses from a functional perspective, so too does their exercises: the therapist should target strength, balance and proprioception, stability, and global movement patterns. Late stage rehabilitation involves power and plyometric/impact work, as well as agility, change of direction, reactionary, and acceleration/deceleration drills, all in a sport-specific context. Overall, full return to sports generally occurs within 6-12 months.

As with anything, sound clinical reasoning and shared decision-making between therapist, patient and/or surgeon needs to be applied to each ACL case, and ACL rehabilitation should never be a ‘one-size-fits-all’ approach.

References
Myklebust, G., et al., Clinical, Functional, and Radiologic Outcome in Team Handball Players 6 to 11 Years after Anterior Cruciate Ligament Injury. The American Journal of Sports Medicine, 2003. 31(6):p.981-989

Frobell et al (2013) – Treatment for acute anterior cruciate ligament tear: five year outcome of a randomised trial. BMJ. 2013 Jan 24;346:f232

Hurd et al (2008) – A 10-year prospective trial of a patient management algorithm and screening examination for highly active individuals with anterior cruciate ligament injury: Part 1, Am J Sports Med. 2008 Jan;36(1):40-7.