Chapter 20: The Knee and Related Structures

Anatomy

Complex joint that endures great amounts of trauma due to extreme amounts of stress that are regularly applied

Hinge joint w/ a rotational component

Functional Anatomy

Capsular ligaments are taut during full extension and relaxed w/ flexion

ACL characteristics

Range of motion includes 140 degrees of motion

Kinetic Chain

Directly affected by motions and forces occurring at the foot, ankle, lower leg, thigh, hip, pelvis, and spine

Determining the mechanism of injury is critical

Observation

Walking, half squatting, going up and down stairs

Swelling, ecchymosis,

Leg alignment

Genu valgum and genu varum

Hyperextension and hyperflexion

Patella rotated inward or outward

Tibial torsion

An angle that measures less than 15 degrees is an indication of tibial torsion

Knee Symmetry or Asymmetry

Leg Length Discrepancy

Palpation - Bony

Palpation - Soft Tissue

Palpation of Swelling

Special Tests for Knee Instability

Valgus and Varus Stress Tests

Used to assess the integrity of the MCL and LCL respectively

Testing at 0 degrees incorporates capsular testing while testing at 30 degrees of flexion isolates the ligaments

Anterior Cruciate Ligament Tests

Drawer test at 90 degrees of flexion

Tibia sliding forward from under the femur is considered a positive sign (ACL)

Should be performed w/ knee internally and externally to test integrity of joint capsule

NOTE: the ACL injury is considered the most serious knee injury.

ACL Ligament tear

Lachman Drawer Test

Pivot Shift Test

Jerk Test

Flexion-Rotation Drawer Test

Posterior Cruciate Ligament Tests

Positive sign indicates a PCL deficient knee

Posterior Sag Test (Godfreyπs test)

Meniscal Tests

McMurrayπs Meniscal Test

Apleyπs Compression Test

Girth Measurements

Subjective Rating

Must assess walking, running, turning and cutting

Co-contraction test, vertical jump, single leg hop tests and the duck walk

Resistive strength testing

Q-Angle

The A - Angle

Patellar orientation to the tibial tubercle

Quantitative measure of the patellar realignment after rehabilitation

An angle greater than 35 degrees is often correlated w/ patellofemoral pathomechanics

Palpation of the Patella

Patella Grinding, Compression and Apprehension Tests

Prevention of Knee Injuries

ACL Prevention Programs

Focus on strength, neuromuscular control, balance

Series of different programs which address balance board training, landing strategies, plyometric training, and single leg performance

Can be implemented in rehabilitation and preventative training programs

Shoe Type

Change in football footwear has drastically reduced the incidence of knee injuries

Shoes w/ more short cleats does not allow foot to become fixed - still allows for control w/ running and cutting

Functional and Prophylactic Knee Braces

Medial Collateral Ligament Sprain

Etiology

Result of severe blow or outward twist forcing the tibia into external rotation

Signs and Symptoms - Grade I

Signs and Symptoms (Grade II)

Signs and Symptoms (Grade III)

Conservative non-operative versus surgical approach

Limited immobilization (w/ a brace); progressive weight bearing and increased ROM over 4-6 week period

Rehab would be similar to Grade I & II injuries

Lateral Collateral Ligament Sprain

Anterior Cruciate Ligament Sprain

Posterior Cruciate Ligament Sprain

Meniscal Lesions

Etiology

Medial meniscus is more commonly injured due to ligamentous attachments and decreased mobility

Also more prone to disruption through torsional and valgus forces

Most common MOI is rotary force w/ knee flexed or extended

Tears may be longitudinal, oblique or transverse

Note: the medial meniscus is attached by the coronary ligaments to the tibia.

Knee Plica (Synovial fold)

Osteochondral Knee Fractures

Osteochondritis Dissecans

Loose Bodies w/in the Knee

Knee Hyperextension

Knee Dislocation?

Doug Ziegler

Bursitis

Patellar Fracture

Injury to the Infrapatellar Fat Pad

Chondromalacia patella

Osgood-Schlatter Disease and Larsen-Johansson Disease

Fracture/Osgood Schlatter Possible

Patellar Tendinitis (Jumperπs or Kickerπs Knee)

Patellar Tendon Rupture

Runnerπs Knee (Cyclistπs Knee)

Runners and cyclists

The Collapsing Knee

Giving way of knee

Knee Joint Rehabilitation

General Body Conditioning

Must be maintained with non-weight bearing activities

Weight Bearing

Initial crutch use, non-weight bearing

Gradual progression to weight bearing while wearing rehabilitative brace

Knee Joint Mobilization

Used to reduce arthrofibrosis

Patellar mobilization is key following surgery

Open versus closed kinetic chain exercises

Closed chain is best, it eliminates the shearing force that open chain would have.

Neuromuscular Control

Loss of control is generally the result of pain and swelling

Bracing

Gradual return to sports specific skills

Progress w/ weight bearing, move into walking and running, and then onto sprinting, change of direction, backing up, & stopping.

Return to Activity

Based on healing process - sufficient time for healing must be allowed

Objective criteria should include strength and ROM measures as well as functional performance tests