Anterior Cruciate Ligaments | Physio4Life

Anterior Cruciate Ligaments

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Anterior Cruciate Ligaments injuries are common in sports people. The annual incidence of ACL ruptures is estimated at 1 of 3,000 in the general population. The incidence rate of ACL tears is between 2.4 and 9.7 times higher in female athletes competing in similar activities.


What is ACL

The ACL’s role is to protect the menisci and bony surfaces of tibia and femur anterior translation and limiting internal and external rotation between the two. The ligament has two separate bundles which have different functions. The anteromedial bundle is tight in flexion as well as rotation in both directions. The posterolateral bundle is tighter in external rotation, limits translation, rotation and hyperextension.


Mechanism of Injury

The common mechanism of injury involves a non-contact situation, when the athlete lands from a jump, pivoting or decelerating suddenly. Video analysis has shown that a trivial contact with another body part such as a touch to shoulder or hand can precede the injury.




Figure 1: ACL Mechanism of Injury

The patient’s subjective history will include:


  • Audible ‘pop’ or ‘crack’
  • Complete tears extremely painful in first few minutes of injury
  • Large immediate swelling (hemarthrosis) develops in the first few minutes following injury
  • Giving way
  • Instability
  • Patella femoral pain


Management options


  • Operative
  • Conservative


Operation process


  • Surgical reconstruction remains the treatment of choice.
  • Advanced techniques of ACL reconstructions are now performed ‘athroscopically’. The aim of ACL reconstruction is to replace ACL with a graft that reproduces the normal functions of the ligament.
  • There are two options of using the hamstring tendons or central third bone patella tendon bone (BPTB). BPTB grafts should be avoided in patients who have kneeling profession or participate in jumping sports with eccentric loading. Hamstring grafts should be avoided in profession or sports that run backwards.


Figure 2 shows the surgery procedure.


acl surgery


Figure 2: ACL Surgery

ACL reconstruction surgery should not be undertaken for at least 3 weeks after injury. As it is thought that earlier surgery had an unacceptable high incidence of joint stiffness (due to scarring in the joint  ‘arhrofibrosis’) It is sensible to delay surgery until the knee has full extension, bends freely, and has little swelling


Conservative Management

Some people whose activity or sport does not involve a large amount of twisting, turning, pivoting maybe able to function without an intact ACL. The patient might have repeated episodes of giving way and increase prevalence of OA.
If the patient has unwillingness to undertake appropriate rehabilitation then surgery may not be successful.


Knee Braces

There are several different types of braces, prophylactic (prevent and minimise severity of knee injury), functional (support), rehabilitation (limit unwanted joint motion and protect tissue healing) and patellofemoral (control patella tracking and alleviate PF symptoms). A brace can be worn with an ACL that has not had surgery, as it is important to help whilst return to sport and playing sport involving rotational forces around the knee.  If the patients decides not to have surgery they must be prepared to work hard on specific rehabilitation, including stretching, strengthening, proprioception and plyometric exercises.


Principles of Rehabilitation

  • Motor learning
  • Agility drills
  • Flexibility
  • Muscle Conditioning
  • Proprioception




Each surgeon has specific guideline and protocol to adhere to in the early stages and will have impact on what can be achieved such as whether exercise prescription, gait re-education will have to factor in limitations and restrictions to ROM through bracing or limiting weight bearing.


Outcomes after ACL reconstruction


  • The majority of ACL reconstruction have good function (65-88%) and able to return to sport in the first year
  • The conservative approach non operative return to sport 19-82% It has been reported that previously injured athletes retire at higher rate than athletes without an ACL injury.
  • The incidence of re injury is 3-6%. Re injury appears to be more significant in the first 12 months of surgery.




Indications for surgery are giving way, repeated episodes of swelling and instability.


Both hamstring and BTBP provide good subjective outcomes and objective stability at 5 years. No significant differences in the rate of graft failure were identified.


Early Management Pre Surgery

24 hours-3 Weeks– Restore full pain free movement in knee, especially extension. Reduce swelling.

(Please note that all post surgical management is under the discretion of the surgeon)

1-2 post surgery
– Restore full movement, relative rest (+/- crutches and knee brace depending on consultant preference)
2-6 Weeks – Restore full knee movement and strength in knee, hip and core stability
6 weeks- 3months– Proprioceptive training, increase CV work (cycling/ rowing/swimming)
3 months- 6 months– Start light jogging
6-9 months– Sport specific Drills/ agility work
9 months– 1 year- Return to Sport


Whether you are being managed conservatively, or surgically, the physiotherapists at Physio4Life are able to take you through your full rehabilitation programme, using our extensive gym facilities to ensure your safe and successful return to sport.


“I am now finally on the road to recovery. I would highly recommend them to anyone.

Clare Fiore

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