Approach

The main goals of treatment for an isolated ACL tear are the following:

  • alleviate symptoms

  • restore function

  • minimise complications.

Initial treatment consists of protected weight bearing, rest, ice, compression, elevation, and bracing. Non-steroidal anti-inflammatory drugs (NSAIDs) or analgesics may help control pain and swelling, but do not alter the course of the injury. Treatment should be tailored to individual preference, along with the exact nature of the injury. The PRICEM acronym defines the initial treatment of all patients.

  • P = Protected weight-bearing exercise with crutches or crutch assisted with a knee immobiliser or similar brace. Avoid prolonged immobiliser use, as severe stiffness and discomfort can develop

  • R = Relative rest

  • I = Ice: useful for initial few days as helps minimise pain and swelling

  • C = Compression

  • E = Elevation

  • M = Medicines (analgesics, NSAIDs as needed).

Patients can be broadly divided into the following three groups:

  • sedentary

  • moderate intensity demands

  • intense dynamic demands

Physiotherapy goals

Gentle (pain-free) active range-of-motion exercises can be instituted within the first few days of injury. Physiotherapy (home or formal) can then proceed with treatment frequency based on the patient's specific situation.

Initial therapy goals include relieving pain and swelling, and re-establishing full range of motion. Subsequent goals include regaining strength, proprioception, and dynamic stability. No methodologically sound evidence has shown superiority of any one particular rehabilitation programme.[68][69]

Note that if the patient experiences recurrent tibiofemoral subluxation episodes, this can lead to meniscal tears and articular cartilage damage.

Sedentary individuals

The first group consists of sedentary people who have low physical demands, are poor surgical candidates, and/or are not interested in pursuing high-level treatment. Such patients may be best treated with home physiotherapy exercises, knee bracing, and activity modification to minimise risk of instability episodes.

Moderate intensity demands

This group includes individuals whose lifestyles feature low to moderate physical activity, with relatively low demands for dynamic knee stability. These people may enjoy recreational golf, swimming, cycling, jogging, doubles tennis, and similar activities in which mild to moderate knee instability may not cause them significant trouble.

Depending upon the severity of the injury and the specific lifestyle demands, formal physiotherapy and customised ACL bracing may work best for this group. Activity modification may also be necessary if they continue to have instability episodes despite this approach.[70][71]

Intense dynamic demands

At the other end of the spectrum are patients with high activity levels and intense physical demands (such as professional athletes) requiring dynamic knee stability. Examples include high-level athletes in sports that require frequent cutting, pivoting, jumping, and deceleration (such as soccer, basketball, rugby, competitive skiing, gymnastics), and people who perform heavy manual labour or who work in a setting where knee instability could prove dangerous (e.g., roofers, construction workers, police, or military personnel). These patients are usually best served by surgical reconstruction of the ACL.

There is evidence to suggest that non-surgical management may be an appropriate choice for some patients with moderate to high activity levels, and that rehabilitation should be considered as a primary treatment option in these patients.[72][73] Studies comparing rehabilitation plus early ACL reconstruction with rehabilitation plus optional delayed ACL reconstruction found no difference in outcomes between these two approaches in young active adults with an acute ACL tear.[72][73][74]

Some individuals, regardless of severity of injury or activity level, tend not to tolerate a conservative approach and may benefit from a surgical approach. This may relate to personality traits or coping style. The decision to choose reconstruction or non-operative treatment should be individualised.

ACL reconstruction

Tears of the ACL should be treated with reconstruction in preference to repair due to the lower risk of revision surgery with reconstruction.[42]

ACL reconstruction is performed primarily to restore the functional stability of the knee, but may also be considered to lower the risk of future meniscus pathology or procedures, particularly for younger and/or more active patients.[42]​ The surgery can be performed soon after the injury, generally as soon as the swelling has resolved and good range of motion has been restored (usually within the first 1-2 weeks after injury in motivated patients who receive proper initial treatment as above). Early reconstruction is recommended as the risk of cartilage and meniscal injury begins to increase within 3 months.[42]​  

Although ACL injuries are most common in people between the ages of 15 and 45 years, older age alone does not necessarily preclude an aggressive surgical approach.[75] Even pre-existing arthrosis does not rule out ACL reconstruction.

Surgeries are usually performed as out-patient procedures under general or spinal anaesthesia, with or without an intra-articular anaesthetic. The surgical time ranges from 1 to 3 hours. Risks of the surgery include infection, deep vein thrombosis/venous thrombo-embolism, neurovascular injury, loss of motion, patellofemoral pain, harvest site pain, patellar fracture, tendon rupture, and pain from hardware.

Specific surgical procedure

In general, there is no definitive superiority of one specific ACL reconstruction procedure over another.[76][77][78][79]​ The choice of graft type should be individualised. Available data and expert opinion suggest that the proficiency and experience of the patient's surgeon should determine which procedure should be done. The American Academy of Orthopaedic Surgeons recommends an autograft, in preference to an allograft, based on improved patient outcomes and decreased ACL graft failure, especially in young and/or active patients.[42]​ In cases where an increased risk of patellofemoral pain would be unacceptable, a hamstring graft to reduce the risk of anterior or kneeling pain, or a bone-patellar tendon-bone graft to reduce the risk of graft failure or infection, may be considered.[42]​ 

Primary ACL repair is rarely performed any more due to generally poor outcomes. ACL bony avulsion injuries may be treated with closed, open, or arthroscopic reduction.[80] Revision of ruptured grafts and bilateral ACL injury requires more complex decision making and often involves the use of allografts. Detailed discussion of these issues is outside the scope of this topic.

Post-operative course

The initial post-operative course depends upon procedure, patient characteristics, and surgeon's preference.

The patient can expect to be up on crutches and wearing a brace that day. Cold, elevation, and other modalities are commonly employed. Physiotherapy begins within the first few days post-operatively. Immobiliser use, bracing, and specific physiotherapy regimens vary.[81][82][83] Ongoing care using braces, rest, non-weight-bearing exercise, and non-steroidal anti-inflammatory drugs can be considered after surgical intervention. Reconstruction frequently allows return to high-demand activities, but does not definitively decrease the risk for post-traumatic arthrosis.[84][85]

Post-operative activity recommendations

These recommendations vary by the exact type and severity of injury, presence or absence of associated injuries, specific surgical technique, rehabilitation protocol, patient's motivation and fitness level, and type and/or intensity of preferred athletic activity. Return to non-contact or low-contact sport (e.g., gymnastics, basketball) may be faster than return to contact sport (e.g., rugby). Return to full activity in under 3 months has been documented, but generally ranges from 6 to 12 months.[86] Running is usually achieved by 4 months, moderate sporting activity by 6 months, and strenuous activity by 8 months postoperatively.[87][88]

Safe return to activity depends upon a dedicated, sequentially phased physiotherapy routine. Appropriate orthopaedic follow-up and physiotherapy assessments are required to ensure that the pace of recuperation is appropriate for the individual patient. A systematic review and evidence statement recommends prehabilitation, followed by 9 to 12 months of post-operative rehabilitation after ACL reconstruction. Progression during rehabilitation, readiness to return to sport and risk for reinjury is measured by strength tests, hop tests, quality of movement and psychological tests.[89]

Psychological monitoring may be particularly relevant for those wishing to return to competitive sport. Results of a systematic review found a relatively low rate of post-operative return to competitive sport following ACL surgery despite a high success rate in terms of knee impairment-based function, thus suggesting that factors other than normalisation of knee function may contribute to return-to-sport outcomes (e.g., psychological factors).[90] Over-zealous return schedules or inadequate physiotherapy can each lead to injury and/or graft failure.[91]

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