Complications Following ACL Reconstruction


While ACL reconstruction techniques have improved, complications still occur during the preoperative, intraoperative, and postoperative periods. Diligent attention to detail and prompt treatment when warranted can minimize complications after ACL surgery.

Preoperative Complications

Performing ACL reconstruction too early after injury increases arthrofibrosis risk. Most evidence suggests delaying until inflammation subsides and range of motion improves.1 Concurrent grade 3 MCL tears may also warrant staged treatment to optimize motion and outcomes.2

Intraoperative Complications

Intraoperative complications include fluid extravasation, compartment syndrome, nerve injury, and graft malpositioning. Avoiding capsular injury, limiting tourniquet time, and careful positioning reduce risks. Nonanatomic graft placement frequently causes loss of motion postoperatively.

Postoperative Complications

Infection, although rare, is the most devastating postoperative complication. Presenting symptoms include persistent pain, swelling and fever. Treatment involves prompt irrigation and debridement, culture-specific antibiotics, and possible graft removal.

Venous thromboembolism occurs in ~3% of ACL reconstructions. Routine prophylaxis is controversial, but should be considered in high-risk patients.5 Tunnel enlargement is common, especially with hamstring grafts. While usually asymptomatic, this complicates revision surgeries.

Loss of motion postoperatively can result from poor rehabilitation compliance, arthrofibrosis, infrapatellar contracture, and cyclops lesions. Early manipulation or surgical release may be required.


Complications after ACL reconstruction require vigilance to mitigate. Surgeons should counsel patients on potential risks and closely monitor the postoperative course. Early intervention maximizes outcomes when complications occur.


1. Shelbourne KD, Wilckens JH, Mollabashy A, DeCarlo M. Arthrofibrosis in acute anterior cruciate ligament reconstruction: the effect of timing of reconstruction and rehabilitation. Am J Sports Med. 1991;19(4):332-336.

2. Petersen W, Laprell H. Combined injuries of the medial collateral ligament and the anterior cruciate ligament. Early ACL reconstruction versus late ACL reconstruction. Arch Orthop Trauma Surg. 1999;119(5-6):258-262.

3. Phelan DT, Cohen AB, Fithian DC. Complications of anterior cruciate ligament reconstruction. Instr Course Lect. 2006;55:465-474.

4. Burks RT, Friederichs MG, Fink B, Luker MG, West HS, Greis PE. Treatment of postoperative anterior cruciate ligament infections with graft removal and early reimplantation. Am J Sports Med. 2003;31(3):414-418.

5. Wirth T, Schneider B, Misselwitz F, et al. Prevention of venous thromboembolism after knee arthroscopy with low-molecular weight heparin (reviparin): results of a randomized controlled trial. Arthroscopy. 2001;17(4):393-399.

6. Wilson TC, Kantaras A, Atay A, Johnson DL. Tunnel enlargement after anterior cruciate ligament surgery. Am J Sports Med. 2004;32(2):543-549.

7. Cosgarea AJ, DeHaven KE, Lovelock JE. The surgical treatment of arthrofibrosis of the knee. Am J Sports Med. 1994;22(2):184-191.

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