What is the recommended treatment for a patient with a complete anterior cruciate ligament (ACL) injury?

Management of Complete ACL Injury

For a complete ACL tear, ACL reconstruction is recommended for younger and more active patients to reduce future meniscal pathology and improve long-term function, with surgery ideally performed within 3 months of injury using either bone-patellar tendon-bone (BPTB) or hamstring autograft. 1, 2

Initial Decision: Surgery vs Conservative Management

The treatment choice depends critically on patient activity level and goals:

• Younger, active patients who wish to return to jumping, cutting, or pivoting sports should undergo ACL reconstruction 1, 2
• Less active, sedentary patients may be managed conservatively with physical therapy, bracing, and activity modification 3
• ACL reconstruction specifically lowers the risk of future meniscus pathology or procedures, particularly in younger and more active individuals 1

Common pitfall: Delaying the surgical decision beyond 3 months in active patients increases the risk of secondary meniscal and cartilage damage 2, 4

Surgical Timing

When surgery is indicated, early reconstruction within 3 months is strongly preferred because the risk of additional cartilage and meniscal injury begins to increase after this timeframe. 1, 2

This represents a shift toward more aggressive early intervention compared to older practices. 2

Graft Selection Algorithm

The choice between BPTB and hamstring autograft should follow this decision tree:

Choose BPTB Autograft When:

• Minimizing graft failure risk is the highest priority 1, 2, 4
• The patient is young and highly active 2, 4
• Reducing infection risk is important 1, 2, 4
• The patient can tolerate anterior/kneeling pain 1

Choose Hamstring Autograft When:

• Avoiding anterior knee pain is critical 1, 2
• The patient has concerns about kneeling pain 1, 2, 4
• Consider adding lateral extra-articular augmentation (ALL reconstruction or LET) to reduce graft failure risk with hamstring grafts 2, 5, 4

Key trade-off: BPTB reduces graft failure and infection risk but increases anterior/kneeling pain, while hamstring reduces donor site morbidity but may have higher re-rupture rates without augmentation. 1, 2, 4

Surgical Technique

Either single-bundle or double-bundle reconstruction can be used, as outcomes are equivalent between the two approaches. 1, 2 This allows surgeon preference and experience to guide technique selection. 2

Reconstruction vs Repair

ACL tears requiring surgery should be treated with reconstruction rather than repair due to lower risk of revision surgery. 1

Concomitant Injuries

For combined ACL/MCL tears:

• Reconstruct the ACL surgically 1
• Treat the MCL non-surgically in most cases, as this yields good outcomes 1, 2
• Surgical treatment of the MCL may be considered only in select cases 1

Post-Operative Management

Do not use functional knee braces routinely after isolated primary ACL reconstruction, as they provide no clinical benefit. 1, 4

Return to Sport Criteria

Use criterion-based rather than purely time-based progression for return to sport decisions:

• Functional evaluation such as hop testing should be considered as one factor in determining clearance 1, 2, 4
• Aim for goal-based rehabilitation with functional criteria rather than rigid time-based protocols 5
• Most patients require 9-12 months of rehabilitation depending on return-to-work or return-to-play goals 5

Critical caveat: Return to running should not occur before 12 weeks minimum to allow adequate graft remodeling. 5

Conservative Management Details (When Applicable)

For less active patients choosing non-operative management:

• Progressive physical therapy focusing on voluntary muscle activation 5
• Education on preventing instability episodes 6
• Activity modification to avoid pivoting and cutting movements 3
• Consider hinged knee bracing during activities 6

Important consideration: Recent evidence shows minimal differences in overall knee function scores between conservative and surgical groups at long-term follow-up, though surgical patients demonstrate significantly higher stability. 6 However, surgical patients experience longer recovery periods before returning to sports activities. 6