Knee Injuries

Idan Ilsar, MDArthroscopy and Sport Injury Unit

Department of Orthopaedic SurgeryHadassah – Hebrew University Medical Center

Today’s Menu

• Meniscal tears

• Anterior Cruciate Ligament (ACL) tears

• Stress fractures

Meniscal injuries

• Prevalence …… (under-reported)

• Surgical incidence is 60-70/100,000/y

Meniscal anatomy

Meniscal anatomy

Meniscal fibers orientation

• Most of the collagen fibers aligned longitudinally

• Some fibers aligned radially - to hold the longitudinal fibers together

• These longitudinally oriented fibers allow for dissipation of compressive forces via hoop stresses

Meniscus

In the past:

“vestigial remnants of a muscle within the knee”

Meniscal tear “Cut it out”

Meniscus - functions

In the present: • Load sharers• Shock absorber• Secondary knee stabilizers• Proprioception• Joint lubrication• Nutrition of articular cartilage

Meniscal motion in ROM

LM>MMTears of medial meniscus > lateral meniscus

Meniscal blood supply

Periphery

RedWhite

• Peripheral 20-30% of MM• Peripheral 10-25% of LM

Meniscal tears

Patient’s history (traumatic)

• Twisting injury• Swelling – after several hours-days (synovitis)

• Pain

• Limp

• Locking

Physical examination

• Swelling

• Intra-articular fluid

• Joint-line tenderness

• Locked knee

• (Quadriceps atrophy if prolonged)

McMurry Test

Apley’s Test

Imaging

• X-Ray

• Ultrasound

• CT

• Bone scan SPECT

• MRI

Knee x-ray

• AP (standing)

• Tunnel

• Lat

Standing vs. ProneRt Knee, 41y male

X- ray

• Knee alignment

• Osteoarthritis

• Osteonecrosis (AVN)

• Chondrocalcinosis

• LBs

• (fracture)

Ultrasound

• Effusion

• Baker’s cyst

• Meniscal excursion

But:• Operator – dependent• Can’t visualize interior aspects

CT scan

• Fractures

• Dislocations

MRI

Treatment

• Analgesics

• NSAIDS

• Rest, Ice, Compression, Elevation

• Elastic bandage

• Physical therapy

Arthroscopy

Outside-In repair

Suture meniscus

PHLM tear

PHMM tear

Future Options

Meniscus implant

ACL tear

• ACL = two-bundle ligament– small anteromedial

– large posterolateral

ACL Anatomy

The anteromedial band is tight in flexion, providing the primary restraint, whereas the posterolateral portion of this ligament is tight in extension.

ACL Mechanics

• Incidence: 30 cases /100 000 people/ year• Noncontact deceleration, jumping, or cutting action• Valgus-external rotation• (hyperextension)• A “pop” is frequently heard or felt• Rapid swelling = hemarthrosis

ACL History and PE

Physical examination

Test LACHMAN

Anterior drawer

PIVOT SHIFT

X-Ray

SEGOND fracture • avulsion fracture of the

lateral capsule

• pathognomonic of ACL tear

MRINormal ACL

MRIACL Tear

• Non operative– If a nonoperative approach is chosen, it should

include an aggressive rehabilitation program and counseling about activity level

– Early Rehab:• Reduce swelling• ROM• Quad/Hamstrings

Treatment

• Non operative– The use of a functional knee brace is controversial

and has not been shown to reduce the incidence of re-injury significantly if a patient returns to high-level sports

Treatment

Operative◦ Primary repair Primary repair was advocated by some authors in the

1950s◦ Although the short-term results were encouraging,

long-term retrospective and prospective reviews showed that as many as 40% to 50% failed within 5 years.

Treatment

Operative◦ ACL Reconstruction

Extraarticular Intraarticular

Autografts : Patellar tendon Hamstring ligament double loop

Allograft

Treatment:

ACL reconstruction

Normal ACL Complete ACL tear=“empty notch”

ACL reconstruction

surgery

Stress fracture

Overload injury Stress fracture

Etiology:

• More load

• More repeats

• Combination

The emphasis is CHANGE

X Ray

Bone Scan

Pathophysiology

• Wolff’s Law: change in external stress leads to change in shape and strength of bone– bone re-models in response to stress

• ABRUPT Increase in duration, intensity, frequency without adequate rest (re-modeling)

• Stress fracture: imbalance between bone resorption and formation

• Microfracture -> continued load -> stress fracture

Anatomic Location

• Tibia - 39.5%

• Metatarsals - 21.6%

• Fibula - 12.2%

• Navicular - 8.0%

• Femur - 6.4%

• Pelvis - 1.9%

Tibial stress fracture

• Local tenderness over middle – distal 1/3rd

• No swelling/redness

Treatment

Treatment

• "Rest"

“Rest” = relative rest

• Stationary cycling

• Elyptical

• Swimming

• Avoid running/jumping

Return to sports

סרגל מאמצים

Shin Splints

Medial tibial stress syndrome (MTSS) / tibial periostitis

• Runners, flat feet• Tibia• Diffuse tenderness

“Cousin” of stress fractures

Similar treatment

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