Updated: 2/12/2019

MCL Knee Injuries

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https://upload.orthobullets.com/topic/3010/images/MRI - MCL injury_moved.jpg
https://upload.orthobullets.com/topic/3010/images/MRI - MCL injury_moved.jpg
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https://upload.orthobullets.com/topic/3010/images/valgus stress.jpg
https://upload.orthobullets.com/topic/3010/images/pellegrini stieda.jpg
Introduction
  • Overview
    • medial collateral ligament (MCL) injury results from excessive valgus stress on the knee, is often an isolated injury and can be managed nonoperatively in the majority of patients 
  • Epidemiology
    • most common ligamentous injury of the knee
      • 40% of knee ligament injuries
    • incidence is likely higher than reported
      • low grade injuries can be missed
    • males > females
    • commonly occur in athletes
      • account of 8% of all athletic knee injuries
      • highest risk in skiing, rugby, football, soccer and ice hockey
  • Pathophysiology
    • valgus stress is the most common mechanism of injury
      • usually with the knee held in slight flexion and external rotation
    • contact injury 
      • more common than noncontact
      • direct blow to the lateral knee with valgus force
      • more often result in high grade / complete ligament disruption than noncontact injury
        • rupture usually occurs at the femoral insertion of the MCL
          • proximal MCL tears have greater healing rates  
          • distal MCL tears have inferior healing and residual valgus laxity
    • noncontact injury
      • less common than contact but more common in skiing
      • pivoting or cutting activities with valgus and external rotation force 
      • more often result in low grade / incomplete ligament injury
  • Associated conditions
    • anterior cruciate ligament (ACL) tear
      • most common associated injury
        • make up ~95% of injuries associated with nonisolated MCL injury
        • combined ACL-MCL is the most common multiligamentous knee injury 
      • presence of hemarthrosis is highly suggestive
      • often associated with high grade MCL injuries
        • grade III > grade II > grade I
    • meniscus tear
      • medial > lateral
      • up to 5% of isolated MCL injuries are associated with meniscus tears
    • Pellegrini-Stieda syndrome  
      • calcification at the medial femoral insertion site 
      • results from chronic MCL deficiency
Anatomy
  • Ligaments of the knee  
  • Anatomy 
    • superficial MCL
      • located in layer II of the medial knee
        • with posteromedial corner ligaments and medial patellofemoral ligament
      • femoral attachment
        • medial epicondyle
        • 1cm anterior and distal to the adductor tubercle
      • tibial attachment
        • proximal tibia periosteum
        • 4.5cm distal to the joint line
        • deep and posterior to the pes anserinus
    • deep MCL
      • located in layer III of the medial knee 
        • with the joint capsule
      • composed of meniscofemoral and meniscotibial ligaments
  • Vascular supply
    • superior medial and inferior medial geniculate arteries 
  • Function
    • superficial MCL 
      • primary stabilizer to valgus stress
        • at all angles of knee flexion
        • greatest stability contribution at 25 degrees knee flexion (78%) 
      • secondary stabilizer to tibial external rotation and anterior/posterior tibial translation
    • deep MCL
      • secondary stabilizer to valgus stress
        • greatest stability contribution at full knee extension
    • other stabilizers of the medial knee
      • static stabilizers
        • posterior oblique ligament
          • resists tibial internal rotation at full knee extension
          • secondary restraint to valgus stress
        • oblique popliteal ligament
        • posterior capsule
      • dynamic stabilizers
        • semimembranosus complex
          • consists of 5 attachments
            • vastus medialis 
            • medial retinaculum
            • pes anserine muscle group
              • sartorius 
              • semitendinosus 
              • gracilis 
Classification
  • American Medical Association (AMA) Classification
    • based on joint laxity alone
      • valgus stress applied with the knee in 30 degrees of flexion
      • graded by amount of medial joint line opening
        • < 3 mm considered physiologic laxity 
    • described in 1966
    • caused confusion and difficulty comparing treatment results
    • Grade I injury
      • 3-5 mm 
    • Grade II injury
      • 6-10 mm
    • Grade III injury
      • > 10 mm
  • Hughston Modification of the AMA Classification
    • based on joint laxity and injury severity
      • severity graded by extent of tenderness and quality of the endpoint with valgus stress at 30 degrees of knee flexion
        • often referred to as "degree" of injury
    • revised in 1994
    • Grade I -- First-degree injury
      • mild
      • localized tenderness
      • firm endpoint
      • no joint laxity
      • stretch injury or few MCL fibers torn
        • no significant loss of ligamentous integrity 
    • Grade II -- Second-degree injury
      • moderate
      • more generalized tenderness
      • firm endpoint
      • +/- mild increase in joint laxity
      • incomplete / partial MCL tear
        • some MCL fibers remain intact, generating the firm end point 
    • Grade III -- Third-degree injury
      • severe
      • generalized tendernesss
      • no endpoint with valgus stress 
      • increased joint laxity
        • third-degree injuries are further subdivided by joint laxity, described by the original AMA system
        • Grade 1+: 3-5 mm
        • Grade 2+: 6-10 mm
        • Grade 3+: > 10 mm
      • complete MCL tear
Presentation
  • History
    • "pop" reported at time of injury
  • Symptoms
    • medial joint line pain
    • difficulty ambulating due to pain or instability
  • Physical exam
    • inspection and palpation
      • tenderness along medial aspect of knee
      • ecchymosis 
      • knee effusion 
    • ROM and stability
      • valgus stress testing at 30° knee flexion
        • isolates the superficial MCL
        • medial gapping as compared to opposite knee indicates grade of injury
          • 1- 4 mm = grade I
          • 5-9 mm = grade II
          • > or equal to 10 mm = grade III
      • valgus stressing at 0° knee extension
        • medial laxity with valgus stress indicates posteromedial capsule or cruciate ligament injury
    • neurovascular exam
      • saphenous nerve exam
    • evaluate for additional injuries
      • ACL
      • PCL
      • patellar dislocation
      • medial meniscal tear
Imaging
  • Radiographs
    • recommended
      • AP and lateral
    • optional view
      • stress radiographs in skeletally immature patient  
        • may indicate gapping through physeal fracture 
    • findings
      • usually normal
      • calcification at the medial femoral insertion site (Pellegrini-Stieda Syndrome)    
  • MRI
    • modality of choice for MCL injuries 
    • identifies location and extent of injury
    • useful for evaluating other injuries  
Treatment
  • Nonoperative
    • NSAIDs, rest, therapy
      • indications
        • grade I 
      • therapy
        • quad sets, SLRs, and hip adduction above the knee to begin immediately
        • cycling and progressive resistance exercises as tolerated
      • return to play
        • grade I may return to play at 5-7 days
    • bracing, NSAIDs, rest, therapy
      • indications
        • grades II
        • grade III  
          • if stable to valgus stress in full extension
          • no associated cruciate injury
      • technique
        • immobilizer for comfort 
        • hinged knee brace for ambulation
      • return to play
        • grade II return to play at 2-4 weeks
        • grade III return to play at 4-8 weeks
      • outcomes
        • distal MCL injuries have less healing potential than proximal injuries
  • Operative
    • ligament repair vs. reconstruction
      • relative indications
        • acute repair in grade III injuries 
          • in the setting of multi-ligament knee injury
          • displaced distal avulsions with "stener-type" lesion
          • entrapment of the torn end in the medial compartment
        • sub-acute repair in grade III injuries
          • continued instability despite nonoperative treatment
            • >10 mm medial sided opening in full extension
        • reconstruction
          • chronic injury
          • loss of adequate tissue for repair
      • technique
        • diagnostic arthroscopy recommended for all surgical candidates to rule out associated injuries
  • Prevention
    • knee bracing
      • functional bracing may reduce MCL injury in football players, particularly interior linemen 
Techniques
  • MCL repair 
    • approach
      • medial approach to the knee 
    • indications
      • acute injuries
    • techniques
      • ligament avulsions
        • should be reattached with suture anchors in 30 degrees of flexion
      • interstitial disruption
        •  anterior advancement of the MCL to femoral and tibial origins
      • internal brace
        • thought to minimize tension on repair during healing process
  • MCL reconstruction
    • approach
      • medial approach to the knee 
    • indications
      • chronic instability  
      • insufficient tissue for repair
    • graft type
      • can use semitendinosus autograft or hamstring, tibialis anterior or Achilles tendon allograft
Complications
  • Loss of motion
  • Neurological injury
    • saphenous nerve 
  • Laxity
    • associated with distal MCL injuries
 

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(SBQ07SM.17) Prophylactic hinged knee bracing for contact athletes has shown a trend towards decreased rates for which types of injuries? Review Topic

QID: 1402
1

ACL tears

5%

(143/2976)

2

ACL and MCL tears

17%

(509/2976)

3

ACL, MCL and ankle ligament tears

1%

(25/2976)

4

MCL and ankle ligament tears

3%

(102/2976)

5

MCL tears

73%

(2183/2976)

ML 2

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PREFERRED RESPONSE 5

(OBQ06.68) All of the following are true regarding grade III medial collateral ligament (MCL) tears of the knee EXCEPT: Review Topic

QID: 179
1

Proximal ruptures have decreased residual valgus laxity following nonoperative treatment than distal ruptures

16%

(573/3495)

2

They result in greater than 10 mm of valgus opening

5%

(181/3495)

3

They can result in a Stener-type lesion

13%

(443/3495)

4

They require operative repair when there is a concomitant anterior cruciate ligament tear

52%

(1819/3495)

5

Proximal ruptures have better healing potential with nonoperative treatment than distal ruptures

13%

(465/3495)

ML 4

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PREFERRED RESPONSE 4
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