Can an ACL tear be diagnosed without scans?
The dreaded anterior cruciate ligament (ACL) tear.
Anterior cruciate ligament ruptures/tears are one of the most common, painful and infamous injuries in sport.
Your ACL is a band of dense connective tissue that is attached to the femur and tibia. The ACL is one of the main ligaments of the knee, lying behind the knee cap inside your knee and adding stability to your knee.
ACL tears most frequently occur in those who play sports involving pivoting, rapid stopping, jumping and cutting movements like football, basketball, netball and soccer.[1] ACL tears can range from mild (small tears/sprains) to severe (when the ligament is completely torn).
Between 2000 and 2015 nearly 200,000 ACL reconstructions were performed in Australia with men aged 20 to 24 years and women aged 15 to 19 years the most commonly affected.[2]
How do ACL tears happen?
Up to 75% of ACL tears happen when there has been little to no physical contact made with the knee or surrounding area.[3] Based on video analysis of injury mechanisms, the typical ACL injury happens when the knee is externally rotated, while launching off the planted foot, suddenly changing direction, decelerating or landing manoeuvres.[4]
How do I know if I’ve injured my ACL?
Most ACL tears are accompanied by hearing and feeling a sudden “pop” and feel that the knee has given out from under you at the time of injury. This is usually followed by tenderness along the joint line, pain, and swelling, decreased or loss of range of motion, and difficulty walking.
Because early detection is the key to achieving the best clinical outcome, physical examination tests should be performed during the acute phase of an injury if possible .If you’re an AFL, NRL, Soccer or Netball fan, chances are you’ve seen a sports physio conduct a hands on assessment of a player’s knee after an injury. Diagnosing an ACL rupture based on a physical examination alone has been a challenge for sports physiotherapists, but there are highly studied and replicable ways of testing whether an ACL tear has occurred on the field.
The Lachman test
Named after John Lachman, the inventing orthopedic surgeon at Temple University in Philadelphia. The Lachman test is designed to identify the integrity of the anterior cruciate ligament by assessing single and sagittal plane instability and is considered one of the most reliable ways to diagnose an ACL injury.[5]
While lying face upwards, a physio places the injured leg in a position of about 20-30 degrees of flexion, one hand on your lower thigh and one hand on your lower leg just below where your leg bends. Gently but firmly pulling your lower leg forward, keeping your thigh stable with their other hand, they test the translation between the tibia in relation to the femur because the ACL should stop a slipping movement if it is intact.
Anterior drawer test
The anterior drawer test (ADT) is commonly done at the same time as the Lachman test to help confirm the diagnosis of an ACL injury. While the pivot shift and Lachman tests are more likely to give an accurate result individually, doing the ADT and Lachman tests together has been shown to give more accurate results than either test by itself.[6]
Sitting on both of your feet, your physio will place their hands around the upper tibia of the injured leg and pull forward. If your shin bone slides forward significantly more on your injured knee as compared to your uninjured knee, then you may have an ACL injury.
The pivot shift test
The pivot shift test is the most specific test to establish an ACL insufficiency.[7] The Pivot Shift Test is also very accurate when performed correctly, but it can be difficult for the person being examined to relax as much needed. Performed on a patient lying flat on their back and knee extended, the sports physio pushes in on the outside of your knee and slowly bends it while holding your shin bone. A positive test for an ACL tear occurs when your tibial plateau moves out of place and then into place when your knee is bent around 30 degrees.[8]
How long does recovery from an ACL tear take?
The recovery period after ACL reconstruction surgery varies from one person to the next and there are many factors that determine how quickly and adequately you will recover and how long it will take until you can get back into the full swing of things.
One of the biggest factors influencing how long ACL surgery recovery takes is whether you have an orthopaedic prehabilitation and rehabilitation plan and you stick to it. A well designed pre ACL surgery body strengthening regime can shave weeks and pain off your post-surgical recovery. The physical shape your affected area is in is one of the strongest predictors of the chances of a fully successful recovery.
It is likely that you have pain and weakness operating in tandem leading up to surgery, but you’re going to need every ounce of strength you’ve got to recover fully. In prehab your local physio will help you build strength and stability where you need it most to ensure you get the most out of your rehabilitation.
Although ACL injury can be diagnosed with hands on physical examinations, imaging with magnetic resonance (MRI) is often required confirm the diagnosis and any other localised injury to the knee. If you think you have an ACL injury, the Lachman and several other tests can be used reliably to confirm the injury and help you figure out what to do next.
[1] Haim A. et al. Anterior cruciate ligament injuries. Harefuah 2006;145(3): 208-14, 244-5.
[2] Increasing rates of anterior cruciate ligament reconstruction in young Australians, 2000–2015 David Zbrojkiewicz, Christopher Vertullo and Jane E Grayson Med J Aust 2018; 208 (8): 354-358. || doi: 10.5694/mja17.00974
[3] Wetters N, Weber AE, Wuerz TH, Schub DL, Mandelbaum BR. Mechanism of Injury and Risk Factors for Anterior Cruciate Ligament Injury. Operative Techniques in Sports Medicine. 2015 Oct 17.
[4] Teitz CC.video analysis of ACL injuries. In:Griffin LY, ed. Prevention of Non contact ACL injuries. Rosemont,IL: American Academy Orthopaedic Surgeons,2001
[5] Dejour D, Ntagiopoulos PG, Saggin PR, Panisset JC. The diagnostic value of clinical tests, magnetic resonance imaging, and instrumented laxity in the differentiation of complete versus partial anterior cruciate ligament tears. Arthroscopy. 2013;29(3 ):491–9.
[6] OSTROWSKI JA, Accuracy of 3 diagnostic tests for anterior cruciate ligament tears, Journal of Athletic Training, 2006, 41(1): 120-122
[7] Benjaminse A, Gokeler A, van der Schans CP (2006) Clinical diagnosis of an anterior cruciate ligament rupture: a meta-analysis. J Orthop Sports Phys Ther 36(5):267–288
[8] Evans J, Nielson Jl. Anterior Cruciate Ligament (ACL) Knee Injuries. [Updated 2019 Mar 8]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2020 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK499848/
