Knee Pathology

Question 1

Ligament Injuries

Answer 1

Collaterals (MCL, LCL

In general the collaterals (MCL and LCL) have better blood supply and heal without injury.

Question 2

Medial Collateral Ligament

Answer 2

Mechanism of Injury ia valgus stress typically to a flexed knee.

2. ACL may also be torn
3. Lateral meniscus may be torn as a result of valgus stress (increase compressive force in lateral compartment.)

Question 3

MCL examination findings

Answer 3

Tender over entire ligament
pain at the end range extension and flexion with grade 1 sprains
may have significantly restricted ROM in both directions with grade II or III sprains

Question 4

MCL Rehab notes

Answer 4

Grade II and III will require immobilization to protect the healing ligament
Encourage early WBAT to encourage quad activity
Avoif frontal and transverse plane stresses initially with grade II and III sprainds

Question 5

Return to Activities with MCL

Answer 5

Return to activities –
•Grade I 1-2 weeks
•Grade II 4-6 weeks
•Grade III 6-10 weeks

Question 6

ACL Injuries

Answer 6

•Individuals typically reports hearing or feeling a “pop”
•Various MOI
–Contact vs. Non-contact
•Gender Issue
–Females 2-8x’s as likely to tear ACL
•Generally requires reconstructive surgery for athletes and active patients or those with instability (“pivot shift”) with ADLs

Question 7

ACL - Mechanisms of Injury: Non-contact Injury Mechanisms

Answer 7

Most ACL injuries occur secondary to non-contact mechanism
–Valgus collapse
–Internal rotation of the tibia on the femur
–Pivoting laterally on fixed foot
–Deceleration (quad active mechanism)
–Hyperextension (or more extended position)

Question 8

6

ACL - Mechanisms of Injury: Contact Injury Mechanisms

Answer 8

•Contact
–Valgus stress to flexed knee with foot fixed
–Forced hyperextension (may tear PCL and even popliteal artery if severe)
–Posterior blow to tibia causing excessive anterior tibia translation

Question 9

ACL: Gender Issue

Answer 9

•Researchers have pointed to several factors to why female athletes are more prone to ACL injury.
–Environmental
–Anatomical
–Hormonal
–Biomechanical
•neuromuscular

Question 10

ACL Reconstruction

Answer 10

Bone-patellar tendon-bone (BTB) autograft is still gold standard, but other graft sources (eg, hamstrings and allografts) are becoming much more common.
•Rehab depends on which procedure was performed.

Question 11

PCL Injuries

Answer 11

Silent group – diagnosis is often overlooked because they are functionally stable
•Various mechanisms of injury
–Posteriorly directed blow to anterior tibia (dashboard injury, soccer, baseball slide)
–Fall onto a flexed knee with planterflexed foot
–Hyperextension
–Hyperflexion

Question 12

PCL Injuries

Answer 12

•Isolated PCL injuries do well treated nonoperatively (conservatively).
–Significant percentage (85%) do well.
•PCL has excellent blood supply, generous synovial envelope, and meniscofemoral ligaments
•PCL reconstruction is generally only considered when gross knee instability is present.

Question 13

LCL Injuries

Answer 13

•Less common
•Grade III – may require surgery
•May also involve posterolateral instability – excessive external rotation of the tibia on the femur producing functional instability
– arcuate ligament/posterolateral capsule
– popliteal complex (popliteus and popliteal fibular ligament)
– Cruciate ligaments

Question 14

Meniscal Injuries

Answer 14

MOI
Forced rotation on flexed knee
Deep flexion occupations
Twisting while WB
2. Medial meniscus more succeptible to injury secondary to being less mobile
3. Patient usually describes a “giving Feeling” and “deep “ pain

Question 15

Meniscal Injuries

Answer 15

•Clinical tests have either poor specificity or sensitivity, and therefore a number of symptoms and positive clinical signs (ie, a cluster) should be present to indicate a probable meniscal tear.
–MOI
–Complaints of intermittent “locking, catching, clicking or buckling” in chronic tears
–Acute or chronic effusion
–Joint line tenderness
–Unable to fully extend the knee (+ bounce home test)
–Positive clinical testing (McMurray’s/Apley’s/Thessalys)

Question 16

Meniscal Injuries

Answer 16

1. Arthroscopic surgery treatment of choice to remove or repair torn meniscus.
2. Location of tear will indicate whether it is repaired or removed

a. Peripheral, good blood supply, repaired
b. Body, poor blood supply, partial menisectomy

Question 17

Knee Dislocation

Answer 17

3 of 4 major ligaments are torn

PCL, MCL, LCL, ACL

Question 18

Osteoarthritis

Answer 18

• primary or secondary
• knee is most common site
• Medial or lateral compartment
• eventual fixed flexion contracture
• Patient c/o morning stiffness
• worse with prolonged standing/ walking positioning

Question 19

OA Interventions

Answer 19

•Modalities
–cryotherapy
•Flexibility ex’s
–Focus on quadriceps, hamstrings, and gastrocnemius
•Strengthening ex’s
–open and closed chain
–may require unloading and/or aquatic therapy in acute phases
•Balance exercises
–Tai chi
•Shoe assessment
–More later
•Orthotics
–Lateral wedge for medial knee OA
•Activity modification
–Minimize weightbearing exposure if applicable

Question 20

Osteochondritis Dissecans

osteochondral lesions

Answer 20

Osteochondral lesion
•Can occur on hyaline cartilage of the patella and femoral condyles.
•Conservative treatment consists of flexibility, quad strengthening, and activity modifications.
•May require surgery (marrow stimulation, OATS, ACI)