Anterior cruciate ligament tears:

Tears to the anterior cruciate ligament (ACL) are not uncommon. They can occur in sports players where there is a sudden change in direction (i.e. football). Likewise, they can occur in the general population, specifically when the lower leg extends forward too much or the knee rotates inwards under load.


Image – Anterior cruciate ligament injury

Image – Anterior cruciate ligament injury


Subjective History:

  • At the time of injury the patient will often describe hearing an audible ‘pop’, ‘crack’ or feeling of the knee giving way
  • Acute initial onset of pain and the development of a haemarthrosis within a few hours of the injury
  • Initially, the patient will have difficulty weight bearing

Objective Examination:

  • On examination there will be restriction of movement, especially loss of extension and widespread mild tenderness. Difficulty with walking and turning on the spot.
  • The Lachmann’s test is positive in ACL disruption and is the most useful test for this condition.

Deciding to have Surgery

The decision to refer patients for an orthopaedic review for consideration of knee surgery will depend on the extent of damage to the ACL and whether it is affecting quality of life. If the knee does not feel unstable and the patient does not have an active lifestyle, they may not require surgery. You can refer to Physiotherapy on the acute knee pathway and the patient will be seen within 72 hours (West Suffolk CCG only).


  • Initial management should involve protection, rest, ice, compression and elevation (PRICE), issue of crutches.
  • Painful activities should be avoided 
  • Progressive loading of the knee through active rehabilitation
  • The treatment regimen can be summarised as follows:

0-48 hrs:

  • Active pain-free exercises (gentle range of movement)

After the first 48 hrs:

  • Gradually increase strength:
  • Active knee flexion and extension
  • Knee brace, active single leg raise and inner range quads. 
  • Hamstring and gluteal strengthening
  • Progress loading – Chair/wall squats and stair step-ups
  • Knee stability exercises  (e.g. pulleys with other leg, one-leg squats)
  • Low impact cardio, cycling and swimming, lower limb strengthening exercises if access to a gym

Functional Strengthening:

  • Bike
  • Pool running
  • Jogging
  • Swimming

Sport Specific skills:

  • Jumping and landing
  • Running-straight line
  • Running-figure of eight
  • Rapid changes of direction (cutting drills)
  • Kicking-gradual increase



  • Image from OpenI – Licensed by CC
  • Image from OpenI – Licensed by CC
  • Image from OpenI – Licensed by CC

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