RESEARCH WATCH – ACL Repair vs Reconstruction


ACL repair: it may sound ‘attractive’, but is it sensible?!


ACL Repair With Suture Ligament Augmentation Is Associated With
a High Failure Rate Among Adolescent Patients.
Gagliardi AG, Carry PM, Parikh HB, Traver JL, Howell DR, Albright JC

Am Journal Sports Med 2019; 47(3): 560-566



Recently there have been a number of individuals promoting and marketing the concept of ACL repair instead of reconstruction. At first glance, this may sound attractive, conceptually, especially in younger patients. However, to what extent might some surgeons be over-promoting this, and to what degree might some people be ‘being over-clever just for the sake of it’, and doing things ‘because they can’ rather than because they should?…

ACL reconstruction is a well-tried and well-tested procedure with excellent outcomes. About 90% of patients are able to return to sport at their same pre-injury level of competition, about 85% of patients are satisfied with their outcome, and 98% say that they would undergo the surgery again [Nwachukwu et al].

Everyone ‘in the know’ knows that not everyone who tears their ACL necessarily needs to have an ACL reconstruction, and some people are able to achieve a good functionally stable knee through committing to an extensive intensive physio rehab programme, to strengthen up their muscles and to speed up their reflexes in order to compensate for ACL deficiency. Probably the best paper in the literature most clearly demonstrating this is the study by Frobel et al, from 2013. This study showed that 50% of patients were able to avoid surgery by committing to appropriate rehab, and it also showed that there was no difference in outcome between those patients undergoing early ACL reconstruction versus those only undergoing delayed surgical reconstruction after attempted rehab had failed.

But for every Ying there’s a Yang! – and the Frobel paper does need to be tempered with the evidence provided by Aichroth (2002), which shows fairly conclusively that ACL tears in children and adolescents should be reconstructed surgically ASAP (not waiting for the growth plates to fuse first), as conservative treatment leads to very poor long-term outcomes. One also has to carefully consider the work of Pinczewski too [Sri-Ram et al]. Pinczewski is one of the most prolific ACL surgeons in the world, and his review of over 5000 ACL reconstructions showed that if you delay ACL surgery by more than 5 months, then this doubles the risk of the patient developing a meniscal tear, and if ACL surgery is delayed for more than 12 months then the risk of the patient developing a meniscal tear increases by a factor of 6! (i.e. 600%!)

Regardless of the above, if the decision has been made to proceed with surgery, then the new question on the block from some quarters seems to be: should the patient have an ACL repair or an ACL reconstruction?

Interest in ACL repair has been rekindled recently because of great advances in the surgical kit available, which has facilitated newer and better surgical techniques. The latest recommended technique for ACL repair is:

– Two lasso-type sutures are passed through the torn ligament stump.
– 4mm bone tunnels are drilled through the distal femur and the proximal tibia, as per the usual standard ACL tunnel placement
– The ACL sutures + a FibreTape internal brace are fixed at the top of the femoral tunnel with an anchor / suture button.
– The distal end of the FibreTape internal brace is then fixed to the anterior tibial cortex with a bone anchor.

Importantly, ACL repair is targeted specifically at:

1) Younger patients (especially children).
2) Patients with a relatively recent / fresh ACL injury.
3) ACL tears where the ligament has avulsed off its proximal femoral attachment: ideally a Sherman Type 1 tear, or else Type 2 at most (Figure 1).

Figure 1. Sherman Type 1 tears are true soft-tissue avulsions, with minimal ligament tissue left on the femur. Type 2 tears have up to 20% of the tissue left on the femur. With Type 3 tears, up to 33% of the ligament tissue is left on the femur. Type 4 tears are mid-substance tears.

The benefits that are quoted for this technique are that it is:

a) Less invasive than a full ACL reconstruction.
b) You don’t need a graft.
c) You preserve the patient’s own ligament tissue.

Figure 2. Intra-operative view of an ACL repair. (Looks a bit ‘ropey’ to me!)

The really important questions that need to be answered here, however, are:

  • Just how potentially ‘less invasive’ is ACL repair compared to ACL reconstruction?
  • Is the argument of ‘avoiding the need for a graft’ really valid?
  • If you do preserve the patient’s own torn ACL tissue, then is this really good, isn’t it??
  • Most importantly, what are the actual outcomes?

Taking these one at a time:

1) Just how potentially ‘less invasive’ is ACL repair compared to ACL reconstruction?

ACL repair requires bone tunnels to be drilled in the distal femur and the proximal tibia that are 4.5mm-diameter.

Well, most ACL tunnels that I use for an ACL reconstruction are 8, 8.5 or 9mm diameter. So, is a 4mm difference in tunnel diameters really that significant and really that big a deal? (Personally, I’d say no!)

Also, in terms of ‘invasiveness’, if you repair a torn ACL in a child and if this the repair is augmented with a FibreTape internal brace, then it is recommended that the FibreTape should subsequently be removed about 3 months later, to avoid it remaining in the knee as a rigid inelastic tether that might affect bone growth. Therefore, ACL repair in children involves 2operations, not one; whereas no second operation is required if the torn ACL isreconstructedinstead of repaired. So, on this basis, ACL repair in children is actually moreinvasive than reconstruction.

2. Is the argument of ‘avoiding the need for a graft’ really valid?

If you do an ACL repair then you don’t need to harvest a tendon autograft from the patient.

Yes, this is true. However, if you use a non-irradiated chemically sterilised tendon allograft (a donor tendon) (which have been shown to be just as good as an autograft), then there’s also no need to harvest any tendons from the patient. So, that’s this argument blasted out of the water too!

3. If you do preserve the patient’s own torn ACL tissue, then is this really good, isn’t it??

When you tear the ACL, significant damage is caused to the ligament, which ends up a bit like a frayed piece of rope in the knee. It’s almost infeasible for a strong ligament to tear or avulse from its attachment without there being significant intra-substance damage to the remaining ligament tissue.

So, if you preserve the patient’s own remaining ACL tissue, is this actually good? Is this remaining tissue actually ‘healthy’, intact and strong? Probably not!

4. Most importantly, what are the actual outcomes?

This is the crunch. What are the actual outcomes? There’s no point in debating theoretical potential benefits without looking at the latest published evidence for what the actual patient outcomes might be. And this evidence is gradually revealing itself within the recent literature….

The publication by Gagliardi et al. in the February edition of The American Journal of Sports Medicine should act as a significant wake-up call for anyone potentially considering ACL repair surgery; either for their patient, or for themselves or for their child. This was a cohort study that looked at 22 consecutive patients from the age of 7 to 18 undergoing ACL repair, comparing them to a larger cohort of patients undergoing ACL reconstruction with a patellar tendon autograft. Among the individuals whose repair or reconstruction did not fail, no differences were seen in return to sport, range of motion or IKDC or Lysholm Knee Scores between the repair vs reconstruction groups. However, the cumulative incidence of graft failure in the first 3 years after surgery in the repair group was 48.8%(95% C.I. = 28.9% to 73.1%), compared to just 4.7%(95% C.I. = 2.1% to 10.3%) in the reconstruction group…

i.e. there was x 10 higher risk of re-rupture with ACL repair!

Accepted, this is just 1 study, plus also, the surgical techniques for ACL repair are still continuing to evolve. However, evidence is evidence, and it is crucial that a fully balanced view is presented to any patient being counselled about the potential options for their knee. If ACL repair is ‘sold’ as some new great ‘better’ option without presenting the full appropriate counter arguments, then the patient will not be fully or appropriately informed. If a patient is not fully informed, then how can they make the right decision, and how can they give ‘informed consent’ to potential surgery?


So, ACL repair may look ‘sexy’, and some orthopaedic surgeons may be selling (over-selling?) this procedure as being ‘better’ than a reconstruction. However, the evidence suggests otherwise, and shows that ACL reconstructionis still the gold-standard for the treatment of ACL-deficiency in children and also in adults with functional instability.


Figure 3.  ACL reconstruction with stump preservation: still the gold standard!

Torn ACL with guyrope passed up the tibial tunnel and up the femoral tunnel, with the tunnels having been drilled preserving as much of the native torn stump tissue as possible.

ACL graft in situ, with the bottom half of the graft sitting ‘inside’ and being enveloped by the native ACL tissue, which gives a better blood supply for faster graft healing / revascularisation / remodelling.



Aichroth PM, Patel DV, Zorrilla P
The natural history and treatment of rupture of the anterior cruciate ligament in children and adolescents.
J Bone Joint Surg [Br] 2002; 84-B: 38-41.  LINK

Frobell RB, Roos HP, Roos EM, Roemer FW, Ranstam J, Lohmander LS
Treatment for acute anterior cruciate ligament tear: five year outcome of randomised trial.
BMJ2013; 346: f232 doi: 10.1136/bmj.f232 (Published 24 January 2013)  LINK

Gagliardi AG, Carry PM, Parikh HB, Traver JL, Howell DR, Albright JC
ACL Repair With Suture Ligament Augmentation Is Associated With a High Failure Rate Among Adolescent Patients.
Am Journal Sports Med2019; 47(3): 560–566.  LINK

Nwachukwu BU, Voleti PB, Berkanish P, Chang B, Cohn MR, Williams RJ 3rd, Allen AA.
Return to Play and Patient Satisfaction After ACL Reconstruction: Study with Minimum 2-Year Follow-up.
J Bone Joint Surg Am. 2017 May 3; 99(9): 720-725.  LINK

Sri-Ram K,
Salmon LJ, Pinczewski LA, Roe JP
The incidence of secondary pathology after anterior cruciate ligament rupture in 5086 patients requiring ligament reconstruction.
Bone Joint J 2013; 95-B: 59–64.  LINK



Mr Ian McDermott


29 March 2019


Ian McDermott