ACL tears – do they all need reconstruction?

June 1, 2018, Dr Chee L Khoo

Yikes, I must have torn my ACL!

For patients with anterior cruciate ligament (ACL) tears, it used to be that conservative treatment is tried first and if the knee joint is symptomatic and/or unstable, then surgery can be considered. But have you noticed that patients are now routinely heading for surgery without a trial of conservative treatment and irrespective of what future demands on their joints may be? As a nation, we seem to have relatively high rates of ACL injuries as well as high rates of knee reconstructions. Is it because we are more active in sports or we are better at diagnosis or is there another sinister reason for the high rates of surgical reconstructions?

Following an ACL tear, what are we and our patients hoping to achieve? We hope to:

  1. Relieve the symptoms of pain and instability,
  2. Return to sporting activities and
  3. Avoid knee reconstruction because of end stage knee osteoarthritis
  4. Prevent re-injury
  5. Prevent injury to other structures in the knee

Most, but not all patients with ACL tears are younger patients participating in competitive sports. Most will opt for ACL reconstruction because that is what is offered by the surgeon especially when they are still very symptomatic in the first few weeks of the injury. Naturally, they all want to return to their competitive sports as soon as possible. They are in pain and the knee is both swollen and unstable.

Yes, ACL reconstruction will improve stability of the knee joint. With intensive rehabilitation post op, most will be able to return to their usual physical and sporting activities even at a very high levels. There is no question that if your patient wants to return to a high level of sporting activities, ACL reconstruction is probably a reasonable option. But what if your patient is a casual jogger, weekend walker or a social soccer player or even a social skier? Does he or she need an ACL reconstruction?

The $64,000 question is “Can non-operative treatment return patients to their pre-injury activities?” Well, obviously, it depends on what those pre-injury activities are. Activities that involve a lot of pivoting and cutting such as football, basketball, soccer, skiing will require a high level of dynamic stability. These patients are unlikely to return to their pre-injury activity without surgical intervention. This is particularly the case if there are other ligament or cartilage injuries.

With systematic rehabilitation concentrating on balance/stability training and strengthening hamstrings, hip and core muscles and ensuring appropriate hamstring to quadriceps ratio (with the hamstrings being dominant), a subset of patients can function without instability or “giving way”. Noyce et al suggested that 1/3 of patients could function this way, while 1/3 can function with modifications of ADL and sporting activities. 1/3 will fail and will require surgical intervention.

Does ACL reconstruction reduce the risk of future osteoarthritis? The risk of osteoarthritis (OA) is significantly increased in the presence of meniscal tears. There are actually very limited studies analysing radiographic or MRI results at medium to long term follow up after knee reconstruction for isolated ACL tears. The results as usual, are conflicting. Some papers report no degenerative evolution without meniscal tears. Others found OA in 39-42% of patients after ACL reconstruction. A recent systematic review concluded that “when reconstructed, isolated ACL-deficient knees have a low risk of osteoarthritic evolution, but mild signs of joint degeneration are reported by the current literature.”

What about non-operative treatment?

Poor muscle function is implicated in the development of OA, exercise, and rehabilitation after an ACL tear may be advanta­geous for preventing the development of OA. A recent systematic review evaluating exercise for ACL injury in reducing OA was inconclusive. However, recent research suggests initial conservative treatment with optional late reconstruction may reduce risk of OA.

In summary, not all ACL injury need operative treatment. Surgical reconstruction may improve stability in some patients but may not reduce the risk of future OA. Some patients may do well with non-operative treatment and may avoid OA with rehabilitation.


Janssen KW, Orchard JW, Driscoll TR, et al. High incidence and costs for anterior cruciate ligament reconstructions performed in Australia from 2003–2004 to 2007–2008: time for an anterior cruciate ligament register by Scandinavian model? Scand J Med Sci Sports 2012; 22: 495-501

Noyes FR, Butler DL, Paulos LE, Grood ES. Intra-articular cruciate reconstruction. I: Perspectives on graft strength, vascularization, and immediate motion after replacement. Clin Orthop Relat Res.


Jones M H, Spindler K P, Fleming B C et al. Meniscus treatment and age associated with narrower radiographic joint space width 2-3 years after ACL reconstruction: data from the MOON onsite cohort. Osteoarthritis Cartilage. 2015;23(04):581–588

Lidén M, Sernert N, Rostgård-Christensen L, Kartus C, Ejerhed L. Osteoarthritic changes after anterior cruciate ligament reconstruction using bone-patellar tendon-bone or hamstring tendon autografts: a retrospective, 7-year radiographic and clinical follow-up study. Arthroscopy. 2008;24(08):899–908.

High prevalence of knee osteoarthritis, pain, and functional limitations in female soccer players twelve years after anterior cruciate ligament injury. Lohmander LS, Ostenberg A, Englund M, Roos H. Arthritis Rheum. 2004 Oct; 50(10):3145-52

Duncan K, et al. A systematic review to evaluate exercise for anterior cruciate ligament injuries: does this approach reduce the incidence of knee osteoarthritis? Open Access Rheumatology: Research and Reviews 2016:8 1–16