Coronal view right knee
Anterior Cruciate Ligament (ACL) Injury
Knee anatomy
Axial view right knee
ACL injury mechanism
Non-contact injury mechanism:
Valgus knee with Tibia internally rotated while femur externally rotated
ACL injury: isolated or combination of knee ligamentous injury. O’Donoghue described the unhappy knee injury triad, comprising injuries to: ACL, medial collateral ligament & the medial meniscus
Contact injury mechanism:
Mild knee flexion with anterior tibia translation
ACL injury symptoms & signs
- Usually non-contact twisting injury
- A “pop or snap” may be experienced at the time of injury
- The injured individual is usually unable to continue with the activity
- Swelling within the 1st hour
- Instability symptoms will manifest with the feeling of the knee giving way, this is especially noticeable when changing direction while running
- Concomitant symptoms & signs of meniscal injury may be present if additional associated injury present
ACL Injury classification
- Isolated ACL injury: partial or complete tear
- Combination of another knee ligamentous or soft tissue injury
- May be associated with knee dislocation injury
ACL injury: isolated or combination of knee ligamentous injury. O’Donoghue described the unhappy knee injury triad, comprising injuries to: ACL, medial collateral ligament & the medial meniscus
ACL injury may be combined with other related knee ligament injuries
ACL injury may be related to knee dislocation
Investigations
Knee X-rays
- Fractures including avulsion cruciate ligament injury can be excluded with knee X-rays
- Associated X-ray radiological avulsion fractures include Segond fracture
MRI scan:
- Gold standard investigation for soft tissue knee injury
- Preoperative planning include associated identification of meniscus tear characteristics
ACL and Meniscus tears
- ACL can be associated with a meniscus tear
- Variation in meniscus tear pattern
Common meniscus tear patterns
Management ACL injury
Non-surgical treatment
- Isolated Grd 1-2
Strengthening with ROM knee exercises.
Progressive return to sport after 6-8 weeks.
Surgery
- Failed conservative treatment for low-grade ACL tear
- Functional instability in an ACL deficient knee
- Multiligamentous knee injury
ACL reconstruction surgery principles
Download ASSIC Performance Fingerprint or Strength & Conditioning apps for guideline ACL rehab routines
References
- Markolf KL, Feeley BT, Jackson SR, McAllister DR: Where should the femoral tunnel of a posterior cruciate ligament reconstruction be placed to best restore anteroposterior laxity and ligament forces? Am J Sports Med 2006; 34:604-611.
- Matava M J, Ellis E, Gruber B. Surgical Treatment of Posterior Cruciate Ligament Tears: An Evolving Technique. J Am Acad Orthop Surg 2009;17: 435-446.
- Mannor DA, Shearn JT, Grood ES, Noyes FR, Levy MS: Two-bundle posterior cruciate ligament reconstruction: An in vitro analysis of graft placement and tension. Am J Sports Med 2000;28:833-845.
- Eakin CL, Cannon WDJ. Arthrometric evaluation of posterior cruciate ligament injuries. Am J Sports Med. 1998;26:96-102.
- Petrie RS, Harner CD. Evaluation and management of the posterior cruciate injured knee. Oper Tech Sports Med. 1999;7:93-103.
- Harner CD, Baek GH, Vogrin TM, Carlin GJ, Kashwaguchi S, Woo SL: Quantitative analysis of human cruciate ligament insertions. Arthroscopy 1999; 15:741-749.
- Takahashi M, Matsubara T, Doi M, Suzuki D, Nagano A: Anatomical study of the femoral and tibial insertions of the anterolateral and posteromedial bundles of the human posterior cruciate ligament. Knee Surg Sports Traumatol Arthrosc 2006;14:1055-1059.
- Edwards A, Bull AM, Amis AA: The attachments of the fiber bundles of the posterior cruciate ligament: An anatomic study. Arthroscopy 2007;23:284-290.
