Hip and Knee

ANTERIOR CRUCIATE LIGAMENT REPAIR (ACL)

The anterior cruciate ligament (ACL) is one of the most commonly injured ligaments of the knee. Injury of the ACL is more common in people who are active in sport.

There are four main ligaments which stabilise the knee, the ACL lies in the centre of the knee and connects the front of the tibia (shin bone) to the back of the femur (thigh bone). The ACL provides anteroposteiror stability. In the case of an ACL tear, the knee will feel unstable and ‘give out’. This is due to the knee having a rotational instability. When weight is borne on the ACL-deficient knee, the femur has a tendency to rotate on the tibia causing pain. As a consequence of this the muscles cannot control the motion of the knee and it gives way. If an unstable knee is not repaired, the constant rotation will cause other structures to be damaged. The most common is a meniscal tear which causes pain and swelling.

COMMON SIGNS AND SYMPTOMS

  • Pop or tear heard or felt at the time of injury
  • An inability to continue the same level of activity eg playing sport or skiing, following the injury
  • Large knee swelling noticed within 6 to 8 hours after the injury (often within 3 hours)
  • Inability to straighten knee
  • Knee giving way or buckling, particularly when trying to pivot, cut (rapidly change direction), or jump
  • Swelling with repeated giving way
  • Occasionally, locking when there is concurrent injury to the meniscus cartilage

THE PROCEDURE

An arthroscopy of the knee joint is performed to assess and deal with any other damage within the knee such as meniscus tears and also to clear the ACL stump from the knee if necessary.

A graft is made using hamstring tendons or sometimes using the quadriceps tendon. The surgery is usually carried out as a day case operation under general anaesthetic, but can also be performed with a local anaesthetic block.

Progress varies from patient to patient and depends on several factors e.g. the severity of the knee injury, the amount of pain and swelling and the speed with which the muscle control returns.

AFTER THE OPERATION

Progress varies from patient to patient and depends on several factors, eg. The severity of your knee injury, the amount of pain and swelling and the speed with which your muscle control returns.

Full recovery takes from 4 to 8 months from the date of the operation. At times you may feel that your progress is not as rapid as you would like or that your exercises are a bit boring. After your operation you will require physiotherapy before and after your discharge home. Rehabilitation is essential to the success of your operation.

POST OPERATIVE ROUTINE

There will be some discomfort from the operation and you will need to take painkillers for the first few days. Ice will also help to reduce swelling and pain. Exercises should start immediately after your operation in order to prevent the knee getting stiff and weaker.

The following exercises will be started from the day of your operation:
  • Tighten the muscles at the front of the thigh with the knee straight. Hold for 5 seconds, then relax.
  • Lie on the floor/bed with a rolled towel propped under the heel and allow the knee to relax into a fully straightened position.
  • Sitting over the edge of the bed, bend and straighten the knee between 90º and 45º only.
  • Lie on your stomach on the floor/bed and gently bend your knee to 90º if possible. Use the other leg to help achieve this passively if necessary.
  • ¼ knee dips supporting 50% body weight by leaning forwards on a table.
Week 2 - 4
  • Continue with the previous exercises and add the following:
  • Increase weight bearing in walking to 75% of body weight.
  • Static bike at week 3, minimal resistance and work up to 20 mins per day.
  • ½ knee dips
  • Increase knee bending to 120º flexion
  • Balance work (using wobbleboard).
Week 4 – 6
  • Discontinue brace at 6 weeks, if muscle control (your physio/consultant will decide this).
  • Progress to full weight bearing.
  • Small step-ups on a low step.
  • Single knee dips to ½ range
  • Swimming – flutter kick only and jogging in pool
  • If you have access to a gym, you can use the following:
  • Bike
  • Stair climber
  • Leg press
  • Hamstring curl
  • Balance work – single leg small knee bend
  • Eyes closed - Throwing ball against a wall
  • Low impact trampoline (light jogging)
Week 6 – 12
  • Continue as for week 4 – 6 plus
  • Controlled step downs from a low step
Week 12 – 16
  • Start straight line jogging at week 12
  • Begin jump activities and increase speed of balance reactions
  • Start cutting and turning activities, eg side running, backward running, short distance speed running.
Week 24
  • Quads and hamstring strength 90% on operated leg. Able to hop on operated leg.
  • May start golf at 6 months
  • Tennis/squash 9 months
  • Football/rugby Training 9 – 12 month

Completion 12 months

This is a rough guideline only and progression depends on your condition, your consultant, your physiotherapist.

The time at which you return to work depends on the nature of the job, the journey to work and the number of stairs. Patients involved in jobs with physical/manual activity may need to take up to two months off work. You should be able to drive after approximately 4 weeks.