ACL injuries

The classic story of a person stopping all of a sudden, side stepping, landing from a jump incorrectly, and the knee giving away, followed by pain in and around the knee especially when you try to put weight on the injured leg, swelling within six hours of injury, popping sound heard at the time of injury – all these events in the knee joint should alert the subject to the most likely diagnosis of anterior cruciate ligament injury.

Three bones – thigh bone (femur), shin bone (tibia), and knee cap (patella) –meet to form a knee joint. Ligaments are connecting structures in between bones. Anterior cruciate ligament is one of the ligaments located inside the knee joint. It runs in the middle of the knee and restrains anterior translation of tibia. Anterior cruciate ligament is complex, for it provides rotational stability, mechanical stability and proprioceptive feedback to the knee.

In recent times, there has been an increase in participation in sports. As a result, there has been an increase in sports related injuries, particularly lower limbs, and more commonly injuries to the knee. One of the most common knee injuries is an anterior cruciate ligament sprain or tear.

Athletes, who are into high demand sports like soccer, football, and basketball, are more likely to injure their anterior cruciate ligaments. Incidence of anterior cruciate ligament injuries in the general population is because of daily routine activities, traffic accidents and recreational activities.

Sprains: Injuries to the anterior cruciate ligament occur along with injury to other structures in the knee, like articular cartilage, meniscus, and other supporting ligaments. Sprain is the word used to define injured ligament and ligaments are graded basing on severity of injury.

  • Grade 1 sprains: The ligament is slightly stretched, but none of the fibres of the ligament are torn.
  • Grade 2 sprains: Ligament is stretched and some of the fibres of the ligament are torn. This is called as partial tear of the ligament.
  • Grade 3 sprains: There is a complete tear of the ligament. The ligament becomes two pieces.


Treatment for anterior cruciate ligament injuries can be divided into conservative and surgical. Age, functional disability and functional requirements are three main factors which will influence the choice of treatment. ACL reconstruction is the surgical procedure used for torn ligament. Reconstruction is done using a graft and the grafts used are either hamstrings tendon or patellar tendon.


Rehabilitation plays an important role in the management of anterior cruciate ligament injuries. Physiotherapy for non-surgical cases: Most of the patients with anterior cruciate ligament injuries are treated conservatively, especially for the general population with grade one and two sprains. Immediately after the injury, the main line of treatment will be to reduce pain, swelling and immobilizing the injured knee. Cryotherapy will help reduce pain, elevating the injured part will decrease swelling, and knee brace will help immobilize the injured knee.

As the initial symptoms subside, gentle isometric exercises are encouraged for both quadriceps and hamstrings muscles which support the knee joint and mobility exercises to encourage the range of motion. Weight bearing on the affected leg is encouraged with the help of brace and assistive devices.

During the final phase of rehabilitation, hamstrings and quadriceps strengthening exercises are added to the treatment regime, which can compensate for the torn ligament’s function. Hamstrings should be strengthened more than quadriceps muscle.

Physiotherapy following surgery

Rehabilitation following surgery is divided into phases.

  • Phase one is immediately following surgery and the duration lasts for about two weeks. The subject’s knee is placed in a brace which will limit the movement for a certain degree, mainly terminal extension of knee. During this period, gentle isometric exercises for quadriceps and hamstrings, mobility exercises to encourage knee range of motion, and partial weight bearing with walker support are advised.
  • Phase two lasts from second week to sixth week. During this phase mobility is given priority, so that full range of motion is achieved and the subject is encouraged to do full weight bearing.
  • Phase three lasts from six to 12 weeks. This phase emphasizes on strengthening programs. Resistance exercises, proprioceptive neuro muscular facilitation techniques, and multiple angle isometrics for quadriceps and hamstrings are encouraged.
  • Phase four lasts from three to six months. This phase is very important for sports people. Sports specific drills, plyometric exercises, exercises to improve proprioception and vigorous strengthening exercises and balance board exercises for knee joint are encouraged.


Strengthening quadriceps and hamstrings can prevent most of the injuries to knee. Some of the exercises which can improve strength in the knee joint are:

  • Knee extensions
  • Hamstring curls
  • Squats
  • Wall squats
  • Wall ball squats
  • Lunges

Some of the knee injuries can get really complicated, and in such cases, prevention is the only cure.

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