Anterior Cruciate Ligament Injuries

The anterior cruciate ligament (ACL) is one of 4 major structures in the knee responsible for stabilisation. Its primary function is to prevent the knee from bending too far. The anterior cruciate ligament (ACL) also plays a role in keeping the knee joint from bending sideways and maintaining rotational stability.The types of injuries to the anterior cruciate ligament (ACL) may include indirect injuries or direct injuries. Those who at risk of these injuries include athletes that participate in cutting sports like rugby, netball, football, tennis, alpine skiing, action cricket, etc. or extreme sports like motocross, enduro motorbiking, kiteboarding, etc. There is also a genetic link and females are more at risk to anterior cruciate ligament (ACL) injuries than males.

Injuries to the anterior cruciate ligament (ACL) may be categorised according to the grade of failure:

Grade 1: mild sprain, the ligament can recover full function

Grade 2: partial tear to one of the bundles (this form of tear is rare in ACL injuries)

Grade 3: complete tear of the ligament

What are the indications for the reconstruction of the anterior cruciate ligament (ACL)?

  • Complete tear of the ligament in adolescents and high-performance athletes
  • Injury to multiple ligaments in the knee
  • Associated meniscus injuries
  • Participants in cutting sports
  • Recurrent feeling of instability in the knee
  • Prevention of meniscus injuries
  • To decelerate chondral cartilage deterioration
  • To enable a unicompartmental knee replacement

Surgical approaches for ACL reconstruction

The aim of this surgery is to use a graft of tendon from the hamstring, quadriceps or patella which has comparable strength, to add to the damaged ACL to reconstruct it by drilling holes in the bones to secure fixation and tensioning of the graft. This surgery can be done using arthroscopic techniques, making it minimally invasive. Using fibre optic instruments and specially designed precise jigs, Dr Morkel is able to harvest the graft through small puncture-like incisions and place the femoral drill holes accurately, whilst following the procedure on monitors.

There are three approaches to this surgery:

  • Doubling or tripling 2 hamstring tendons (semitendinosus and gracilis) – this method provides a strong and long enough graft that is used and the majority of ACL reconstructions in the world these days.
  • Using the middle 3rd patellar tendon - with 2cm bone blocks on each side was the original graft of choice and still gives excellent results.
  • Using a graft from the quadriceps tendon - with 2cm patellar bone block also provides an excellent graft

The results of ACL reconstructions by modern methods are improving all the time. There are many examples of high-performance athletes that that returned to high demand sports at the highest level after ACL reconstructions. There is also a constant search for improvement in the results of this very common injury. The recurrence rate of ACL reconstruction failures, although less than 20%, is still a field of constant research. Substituting the ACL ligament with the patient's own substitute tendon (hamstrings, quadriceps or patellar tendons) still gives the best results.

The only downside to using the patient's own tendons is the problems that are experienced with the donor site. Each of these particular graft materials has their own set of complications/side effects but are still preferred over allograft (cadaver tendons treated to make it safe for implantation) and synthetic ligaments (LARS ligaments). ACL reconstruction can be augmented with extra-articular reconstruction in specific cases. Dr Morkel prefers Lemaire iliotibial band augmentation procedure.

Recovery after ACL reconstruction surgery

In most cases, a one night stay in the hospital is sufficient as long as the patient can mobilise the knee safely. Partial weight-bearing with crutches is usually required for 4 weeks. A structured rehabilitation program should be followed for the next 6 months until a follow-up with Dr Morkel. It is essential that the athlete/patient recovers fully before he or she can return to the chosen sport. The patient may be able to return to cutting and contact sports from 9-12 months.

Frequently asked questions

Does an ACL rupture require ACL reconstruction surgery?

For some patients, an isolated ACL rupture can be treated conservatively without the need for surgery. It will, however, mean that an adjustment will need to be made in sports participation and diligent conditioning of the stabilisers of the knee. In cases where there is associated injuries such as an MCL, PCL, posterolateral corner and meniscus injury, then the ACL would need to be reconstructed surgically. An untreated ACL injury in a growing child is also associated with long-term problems in the knee joint and should thus be operated on.

Can ACL injuries be prevented?

There is certainly a higher incidence of ACL injuries with female athletes and certain sports, for instance, netball and female soccer. A specific injury prevention program focusing on core stability, prevention of valgus knee movement on jumps and generalised hamstring conditioning/centralisation can prevent ACL injuries. Hamstring fatigue and loss of footing or too much grip of the shoes on the playing surface are all factors that can lead to an ACL injury. Wearing the correct shoe for each surface is also important. All young female athletes that participate in high-risk sports, like netball in female soccer, should follow an ACL injury prevention program.

How is an ACL injury diagnosed?

There is usually a definite injury, forcing the athlete not to finish the match or training session. Often this injury is slipped of the foot or twist of the knee whilst changing direction. The knee swells up acutely in isolated ACL injuries. The swelling can subside quite quickly, but the knee will tend to buckle as soon as athlete returns to running. ACL is injuries also happen during high velocity injuries in extreme sports and motor vehicle accidents. There are 3 clinical tests, anterior drawer, Lachmann and pivot shift tests that helps with the diagnosis. Sometimes these clinical test can be difficult in very muscular patients or when the knee is still too painful. X-rays can have subtle bony injuries that are associated with ACL injuries (avulsion fracture or Second fractures) but the gold standard special investigation to diagnose ACL, and associated injuries, is the MRI scan

How is an ACL injury diagnosed?

Usually an ACL injury will be painful enough for the athlete/person to see a doctor. It is often caused by a slip of the foot or twist of the knee whilst changing direction. An ACL injury will cause the knee to swell significantly and while the swelling can subside quite quickly, the knee will tend to buckle as soon as the person returns to running. ACL injuries can also occur due to high-velocity injuries in extreme sports or motor vehicle accidents. To diagnose an ACL injury, Dr Morkel may use three clinical tests: the anterior drawer, Lachmann and the pivot shift test. When necessary, x-rays can also help diagnose any subtle bony injuries that are associated with ACL injuries (like avulsion fractures or second fractures). In most cases, the gold standard special investigation to diagnose an ACL injury is an MRI scan.

When is the right time for ACL reconstruction?

In most cases an isolated ACL ligament reconstruction can be staged, as long as the mobility of the knee is fine and the quadriceps and hamstring strength is maintained. There are special cases where earlier reconstructions will give better results, but when this is the case, Dr Morkel will discuss this with you. ACL ligament reconstructions, in combination with medial collateral ligament (MCL) reconstructions, also lead to better results. When there is an associated meniscus tear during the injury, the ACL needs to be reconstructed in addition to the repair of the meniscus. Usually, athletes fair better with an early ACL reconstruction, as long as the growth plates are respected. In a very young patient with an ACL ligament injury, special care needs to be taken with bony drill holes to prevent early growth plate closure and stunted growth of the bone.

Which graft option is the best?

Excellent results can be achieved with all 3 different autograft options (hamstrings, patellar tendon and quadriceps tendon). When choosing which of the three to use as a graft, the morbidity of the donor site plays a key role in Dr Morkel's decision. Each graft has its pros and cons. Patellar tendon graft harvesting as a reported a higher incidence of knee pain in the long run. Hamstring tendon harvesting, although strength returns to 100% within a year, has a higher incidence of hamstring spasms. Quadriceps tendon harvesting seems to have fewer complications. The contact sportsman and high demand patient certainly require a lower recurrence rate and low donor site complications incidence. When is extra-articular, augmentation procedures indicated? Extra-articular augmentation procedures are indicated for revision ACL reconstructions, medial meniscus repairs, severe rotational instability and severe anterior drawer tests, smokers and professional contact athletes. Will I wear a brace after the operation? A brace is only indicated when there is an associated injury, for instance, meniscus repair, collateral ligament injuries or PCL reconstruction in addition to the ACL reconstruction. What is the role of physiotherapy and biokinetics in ACL injuries? Physiotherapists play an important role in ensuring a full range of motion with an exercise program to begun prior to surgery to protect the knee, as well as 4 weeks after surgery. Biokinetics is also important from 5 weeks to 1 year after surgery to ensure the athlete can return to his or her chosen sport.