The acutely injured knee can often be challenging to assess when there is no associated fracture. Identifying the possible non-bony acute pathology is important to help discern the most appropriate approach to treatment for the patient. 

Assessment

History

  • Mechanism of action 
      • Contact
      • Twist/Pivot 
  • Onset of symptoms:
      • Immediate vs delayed symptoms
      • Able to finish their activity?
  • Symptoms
      • Where the pain is felt
      • Mechanical symptoms; catching, clicking, locking
      • Giving out/unstable
  • Past Medical History for Risk Factors:
      • Medications (steroids, fluroquinolones), diabetes, connective tissue disease
      • What is their baseline function? i.e.: young athlete vs injury during bed to wheelchair transfer 

Exam

  • Position:
      • Supine
      • Bilateral leg exposure
      • Most comfortable position for patients
      • Support leg as much as possible throughout exam (provide towel under knee for comfort)
      • Limit movement
  • Observe:
    • Can they ambulate?
  • Analgesia:
      • Prior to exam
      • +/- Procedural sedation for patella reduction 
  • PoCUS:
      • Helpful to identify fractures, tendon injury, effusions
  • Arthrocentesis: 
      • Should be considered in patients with acute knee injury with a large effusion, decreased ROM and normal X-Ray
      • Arthrocentesis performed in the ED for ACL injury causing effusion, pain and decreased ROM showed improvement in pain, range of motion and accuracy of exam maneuvers at follow-up visit (Wang et al. 2016).
  • Traumatic Hemarthrosis (Potpally et al 2021)
      • 70% of ACL tears
      • 10% of patella subluxation/dislocation 
      • 10% of meniscal tears
      • 5% of osteochondral fractures
      • 5% other (i.e.: PCL tears) 
  • Movements to check:
      • Check Extensor mechanism while supine, not sitting as ITB is a knee extensor at 30 degrees of knee flexion when it moves from posterior to anterior over the lateral femoral condyle
      • Stability (ligaments) 
      • Intra-articular (meniscal)

Ottawa Knee Rules

Patients presenting with acute knee injury require X-ray if:

Pathologies

 

Occult Knee Dislocation

  • Mechanism of injury:
      • Dashboard/MVC
      • Ground level falls in elderly or obese patients
      • 20-50% of knee dislocations will spontaneously reduce prior to ED arrival
  • Exam:
      • Ligamentous instability in at least 3 of the 4 ligatments
  • ED investigations:
      • X-Ray to rollout fracture
      • Ankle-Brachial index
      • CT-A
  • ED Management:
      • If hard signs of vascular injury; STAT vascular consult +/- vascular injury
      • If abnormal ABI –> CT-A (consult ortho +/- vascular)
      • If normal ABI –> consult ortho
  • Referral:
      • Consultation in the ED for admission/management 

knee

 

Patella Dislocation

  • Mechanism of Injury:
      • Planted foot with internal rotation/twisting on a valgus flexed knee
      • Dancing, baseball swing, quick lateral change 
      • Lateral dislocation most common 
  • Exam:
      • Laterally displaced patella for lateral dislocation
      • Subluxation: positive patella apprehension test
  • Investigations:
      • X-Ray with skyline views to rollout acute fracture (osteochondral fractures commonly missed)
      • X-Ray not required prior to reduction (Krause et al, 2013)
  • ED Management
      • Reduce by straightening leg and gently tip & tilt patellar laterally then medially
      • Immobilize
      • Counsel
          • Brief immobilization for comfort (3-4 days)
          • Ice and elevate
          • Weight bearing as tolerated
          • Limit walking, standing, repetitive bending
          • Use a patella restraining brace
          • Physiotherapy for retraining/strengthening quads
          • Athletes return to play in 4-6 weeks
    • Referral:
        • Plater clinic if: associated fracture, recurrent dislocations, associated injury (eg: ACL, MCL tears)
        • All reduced dislocations can be referred to plaster clinic/orthopedics, or if there are absolutely no concerns for other injuries they can be sent to their family physician or sports medicine specialist. 
        • Physiotherapy 

 

Patella Tendon Rupture

  • Mechanism of injury:
      • Jumping sports
      • Sudden quadriceps contraction with flexed knee (patellar tendon injury)
      • Sudden quadriceps contraction when landing from a jump with a flexed knee (Quads tendon injury)
  • Exam:
      • Extensor mechanism will not be intact, therefore unable to complete straight leg raise
      • Defect distal to the patella (defect proximal to patella suggests quads tendon rupture) 
  • ED Investigations:
      • X-Ray to rule out fracture – patella alta (patella tendon rupture), patella baja (quad tendon rupture)
      • PoCUS: identify the tendon defect
knee

Patelle Baja

  •  ED Management:
      • Immobilize in zimmer
      • Consult ortho in ED to book for surgery
  •  Referral:
      • Surgical intervention required  

 

Ligamentous Injury

 

Anterior Cruciate Ligament:

  • Mechanism of injury:
      • Non contact: pivot
      • Contact: blow to lateral aspect of knee
  • Exam:
  • ED Investigations:
      • X-Ray to look for Segond or tibial spine fracture
  • ED Management:
      • Crutches, WBAT, RICE
  • Referral:
      • In young athletes that you are confident have an ACL tear -> outpatient MRI + ortho referral
      • If you are not confident that there is a significant injury, they need to be re-examined in ~1wk -> family physician or sports medicine referral
      • Minor injury or poor baseline -> family physician

 

Medial Collateral Ligament

  • Mechanism of injury:
      • Contact: blow to lateral aspect of knee
  • Exam:
      • Laxity/soft end feel with valgus stress test at 30 degrees of knee flexion for isolated MCL injury
  • ED Investigations:
      • X-Ray to rule out fracture
  • ED Management:
      • Crutches, WBAT, RICE
  • Referral:
      • In young athletes that you are confident have at least a MCL tear -> outpatient MRI + ortho referral
      • If you are not confident that there is a significant injury, they need to be re-examined in ~1wk -> family doctor or sports medicine referral

 

Lateral Collateral Ligament

  • Mechanism of injury:
      • Contact: blow to medial aspect of knee
  • Exam:
      • Laxity/soft end feel with varus stress test at 30 degrees of knee flexion for isolated LCL injury
  • ED Investigations:
      • X-Ray to rule out fracture
  • ED Management:
      • Crutches, WBAT, RICE
  • Referral:
      • Family physician or sports medicine specialist for re-examination +/- imaging
      • Isolated LCL injuries are rare

 

Posterior Cruciate Ligament

  • Mechanism of injury:
      • Dashboard
      • Hyperflexion with plantar flexion of foot
  • Exam:
      • Posterior Sag Sign
      • Posterior Drawer
      • Could have valgus/varus laxity at 0 degrees of knee flexion
      • Dial test to differentiate isolated PCL vs associated injuries (PLC)knee
      • ED Investigations:
          • X-Ray to rule out fracture
      • ED Management:
          • Crutches, WBAT, RICE
      • Referral:
          • Family physician or sports medicine specialist for re-examination +/- imaging.
          • In young athletes that you are confident have at least a high grade PCL tear -> outpatient MRI + ortho referral

 

Posterolateral Corner

  • Mechanism of injury:
      • Non contact: external rotatory/twisting
      • Contact: blow to anteromedial aspect, hyperextension, MVC (knee dislocation)
  • Exam:
      • Varus and Valgus stress at 0 degrees of knee flexion
      • Dial test
      • Reverse pivot shift test (not accurate in the ED)
  • ED Investigations:
      • X-Ray to rule out fracture
  • ED Management:
      • Unstable knee (at least 3 ligaments torn) -> ortho in the ED
      • Crutches, WBAT, RICE
  • Referral:
      • Sports medicine specialist or family physician for re-examination +/- imaging

 

Meniscus

  • Mechanism of injury:
      • Non contact: sudden change in direction – commonly seen in soccer, basketball, football and rugby
  • Exam:
    • ED Investigations:
        • X-Ray to rule out fracture
    • ED Management:
        • Crutches, WBAT, RICE
    • Referral:
        • If mechanical symptoms (locking) -> Outpatient MRI + ortho referral
        • If no mechanical symptoms -> family physician or sports medicine specialist for re-examination +/- imaging

References

Cardone, D. A., & Jacobs, B. C. (2022). Meniscal injury of the knee. UpToDate. http://aplicacionesbiblioteca.udea.edu.co:4560/contents/meniscal-injury-of-the-knee?source=search_result&search=lesión+de+meniscos&selectedTitle=1~45

Chahla, J., Moatshe, G., Dean, C. S., & Laprade, R. F. (2016). Posterolateral Corner of the Knee: Current Concepts. The Archives of Bone and Joint Surgery, 97(9), 97–103.

Guillodo, Y., Rannou, N., Dubrana, F., Lefèvre, C., & Saraux, A. (2008). Diagnosis of anterior cruciate ligament rupture in an emergency department. Journal of Trauma – Injury, Infection and Critical Care, 65(5), 1078–1082. https://doi.org/10.1097/TA.0b013e3181469b7d

Guiraud, K., Silvestre, G., Bastin, C., Lecouvet, F. E., Benitez Masip, A., Boyadzhiev, D., Meert, P., & Thienpont, E. (2022). Higher sensitivity with the lever sign test for diagnosis of anterior cruciate ligament rupture in the emergency department. Archives of Orthopaedic and Trauma Surgery, 142(8), 1979–1983. https://doi.org/10.1007/s00402-021-04154-x

Koster, C. H., Harmsen, A. M. K., Lichtenberg, M. C., & Bloemers, F. W. (2018). ACL injury: How do the physical examination tests compare? Journal of Family Practice, 67(3), 130–134.

Krause, E. A., Lin, C. W., Ortega, H. W., & Reid, S. R. (2013). Pediatric lateral patellar dislocation: Is there a role for plain radiography in the emergency department? Journal of Emergency Medicine, 44(6), 1126–1131. https://doi.org/10.1016/j.jemermed.2012.11.014

Lelli, A., Di Turi, R. P., Spenciner, D. B., & Dòmini, M. (2016). The “Lever Sign”: a new clinical test for the diagnosis of anterior cruciate ligament rupture. Knee Surgery, Sports Traumatology, Arthroscopy, 24(9), 2794–2797. https://doi.org/10.1007/s00167-014-3490-7

Maffulli, N., Binfield, P. M., King, J. B., & Good, C. J. (1993). Acute haemarthrosis of the knee in athletes. A prospective study of 106 cases. Journal of Bone and Joint Surgery – Series B, 75(6), 945–949. https://doi.org/10.1302/0301-620x.75b6.8245089

McQuivey, K. S., Christopher, Z. K., Chung, A. S., Makovicka, J., Guettler, J., & Levasseur, K. (2019). Implementing The Lever Sign in the Emergency Department: Does It Assist In Acute Anterior Cruciate Ligament Rupture Diagnosis? A Pilot Study. 57(6), 805–811.

Meserve, B. B., Cleland, J. A., & Boucher, T. R. (2008). A meta-analysis examining clinical test utilities for assessing meniscal injury. Clinical Rehabilitation, 22(2), 143–161. https://doi.org/10.1177/0269215507080130

Orlando Júnior, N., de Souza Leão, M. G., & de Oliveira, N. H. C. (2015). Diagnosis of knee injuries: comparison of the physical examination and magnetic resonance imaging with the findings from arthroscopy. Revista Brasileira de Ortopedia (English Edition), 50(6), 712–719. https://doi.org/10.1016/j.rboe.2015.10.007

Parwaiz, H., Teo, A. Q. A., & Servant, C. (2016). Anterior cruciate ligament injury: A persistently difficult diagnosis. Knee, 23(1), 116–120. https://doi.org/10.1016/j.knee.2015.09.016

Potpally, N., Rodeo, S., So, P., Mautner, K., Baria, M., & Malanga, G. A. (2021). A Review of Current Management of Knee Hemarthrosis in the Non-Hemophilic Population. Cartilage, 13(1_suppl), 116S-121S. https://doi.org/10.1177/1947603520942937

Rossi, R., Dettoni, F., Bruzzone, M., Cottino, U., D’Elicio, D. G., & Bonasia, D. E. (2011). Clinical examination of the knee: Know your tools for diagnosis of knee injuries. Sports Medicine, Arthroscopy, Rehabilitation, Therapy and Technology, 3(1), 1–10. https://doi.org/10.1186/1758-2555-3-25

Sharareh, B., Skaggs, D., & Taylor, B. (n.d.). Knee & Sports High-yield topics. Orthobullets. Retrieved September 10, 2022, from https://www.orthobullets.com/topic/dashboard?id=225&specialty=225&expandLeftMenu=true

Strudwick, K., McPhee, M., Bell, A., Martin-Khan, M., & Russell, T. (2018). Review article: Best practice management of common knee injuries in the emergency department (part 3 of the musculoskeletal injuries rapid review series). EMA – Emergency Medicine Australasia, 30(3), 327–352. https://doi.org/10.1111/1742-6723.12870

van Eck, C. F., van den Bekerom, M. P. J., Fu, F. H., Poolman, R. W., & Kerkhoffs, G. M. M. J. (2013). Methods to diagnose acute anterior cruciate ligament rupture: A meta-analysis of physical examinations with and without anaesthesia. Knee Surgery, Sports Traumatology, Arthroscopy, 21(8), 1895–1903. https://doi.org/10.1007/s00167-012-2250-9

Wang, J. H., Lee, J. H., Cho, Y., Shin, J. M., & Lee, B. H. (2016). Efficacy of knee joint aspiration in patients with acute ACL injury in the emergency department. Injury, 47(8), 1744–1749. https://doi.org/10.1016/j.injury.2016.05.025