Knee joint

Chapter 21

The Knee

Copyright 2005 Lippincott Williams & Wilkins

Anatomy


Subdivisions of Synovial Cavity


Myology

Anterior

 Rectus femoris

 Vastus lateralis

 Vastus intermedius

 Vastus medialis

Medially

 Gracilis

 Adductor longus, brevis, magnus

Posterior

 Biceps femoris

 Semitendinosus

 Semimembranosus

Laterally

 TFL/ITB (affected by gluteus maximus, etc.)


Kinematics – Tibiofemoral Joint

ROM

Flexion/extension 0-140 degrees

Extension – Limited by ACL and PCL, posterior capsule, anterior horns of menisci.

Flexion – Limited by cruciate ligaments and posterior horns of menisci.


Kinematics – Patellofemoral Joint

During Flexion

0 –90 degrees – Contact area is more central portion of patella.

135 degrees – Medial facet contacts medial femoral condyle.

Ideal static – Patella positioned slightly laterally–Remains in trochlear groove until 90 degrees.

Extension – Patella moves superiorly along line of femur if VMO and VL are in balance.


Rolling with Anterior,

Anterior/Posterior Glide


Anatomic Impairments

Genu Valgum

– Femur descends obliquely in a medial direction (normal 5–10 degrees).

– Greater load on lateral compartment.

– Associated with coxa varum at hip.

Genu Varum

– Angulation of femur and tibia is 0 or laterally orientated.

– Increases load on medial compartment.

– Associated with coxa valgum.


Genu Valgum/Varum


Examination and Evaluation

Components of Knee Assessment

Pelvis/hip – Muscle length, alignment, performance, capsule mobility

Knee – ROM, ligament stability, meniscal tests, extension overpressure response, palpation

Patella – Orientation, VMO/VL relationship, lateral retinacular tightness

Tibia – Torsion, tibial varum/valgum, rotation

Foot – Pronation/supination, rear/forefoot alignment


Muscle Performance

Muscles commonly tested

 Medial and lateral hamstrings

 Quadriceps

 Gluteal muscles

 Iliopsoas

 Gastroc-soleus

 Hip rotators

 Posterior tibialis


Therapeutic Exercise Intervention for

Physiologic Impairments

Mobility Impairment – Hypomobility

 Glide and joint distraction techniques

 Patellar mobilization

 Quadriceps, hamstring stretches

 Abdominal support


Quadriceps Stretch for Hypermobility


Hypermobility

 Associated with patellar instability

 At risk for ACL injury

 Clinical signs – Knee recurvatum and subtalar pronation

Treatment

 Postural retraining of lower extremity and lumbopelvic region

 Co-contraction of lower extremities (high reps-low resistance)


Impaired Muscle Performance

Treatment – Strength, endurance, and power training activities.

Neurologic Causes :

 Lumbar spine injury or disease

 MS

 Parkinson’s disease


Muscular Strain

 Hamstrings and quads most commonly injured.

Treatment:

 Bleeding control followed by progressive mobility and strengthening.

 Plyometrics if within patient’s functional abilities and goals.


Disuse and Deconditioning

 Occurs primarily at quadriceps.

Treatment:

 Strengthening activities for the quadriceps.

 Focus on primary cause of disuse.


Therapeutic Exercise for Common

Diagnoses – Ligament Injuries

ACL

 Usually occurs due to hyperextension, deceleration, rotational injury.

 Frequently associated with injuries to MCL.

Treatment:

 Avoid resisted open chain (OC) exercises.

 Closed chain (CC) exercises including deceleration, cutting maneuvers, lateral movements, resisted rotational movements, and activities on unstable surfaces.


PCL

 Most often a blow to anterior aspect of tibia.

 Occasionally, hyperflexion/extension or varus/valgus injury.

Treatment:

 Avoid open chain exercises.

 Closed chain exercises are used.


MCL

 Usually torn as a result of valgus stress by a lateral blow or forced abduction of the tibia (skiing).

LCL

 Much less common than MCL injuries.

 Commonly results from hyperextension varus stress.

Treatment:

 Loading must occur in frontal and transverse planes.


MCL Exercises


Treatment of Ligament Injuries

 Pain can be managed with physical agents, mechanical and electrotherapeutic modalities.

 Therapeutic exercise (AROM, PROM).

 Joint mobilization may be necessary.

 Home program may include exercises to increase ROM and neuromuscular re-education.


Treatment of Ligament Injuries (cont.)

 Acute

 Aquatics is excellent for:

 Mobility, gait, initiating balance, walking, physiologic stretching, leg kicks, toe raises, single leg balance, and squats.


Progression

 Continuation training and progressing to non-device-assisted exercises.

 Land-based CC exercises.


Late Stage

 Resisted OC exercises.

 Functional specific drills.


Fractures

1.

Patellar fracture

2.

Distal femur fracture

3.

Tibial plateau fracture

4.

Treatment

 Surgically fixated – AROM/PROM exercises for flexion and extension.

 Quadriceps and hamstring setting exercises.

 Weight-bearing CC exercises – Based on healing and

NM control.


Menisci Injuries

 Partial meniscectomy

 Most often injured traumatically

 Degenerative tears

Treatment:

 Weight-bearing through large ROM should be avoided.

 Partial weight-bearing as tolerated is permitted.

 Progression is dictated by procedure.


Self-Management Techniques


Surgical Procedures

1.

Osteotomy – Treatment is guided by requirements of a healthy joint. Restoring ROM is crucial to ensure proper distribution of loads.

2.

Total knee arthroplasty – Patellar instability can be an issue in 5 –30% of TKAs. Limitations at hip and ankle can profoundly affect post-op function.


Tendinopathies

Patellar Tendinopathy Treatment

 Focuses on patellar tendon’s role in decelerating knee flexion during functional activities.

 Stretching exercises are combined with eccentric quadriceps contractions progressing in velocity to match that of daily activities.

 OC or CC can be used; however, CC is preferred.


Iliotibial Band Syndrome

Treatment:

 Postural education

 Exercises for underlying impairments

(e.g., hip rotator weakness)

 Stretching of hip and knee musculature


Patellofemoral Pain Syndrome (PFPS)

 Aggravated by knee extension activities.

 For example, ascending/descending stairs, squatting, rising from chair, jumping.

 Can be caused by frank dislocation, commonly associated with hypermobility of patella, tenderness of patellar borders and femoral condyles, shallow intercondylar groove.


PFPS (cont.)

 Overuse.

 Poor tracking of patella (shape of osseus surfaces or muscle imbalance).

 Q-angle greater in those with PFPS (excessive pronation of foot?)

 Greater degree of lateral patellar tilt.

 Muscle imbalance (VMO:VL).


PFPS Treatment

 General quadriceps strengthening.

 All exercises to be performed in pain-free ROM.

 Exercises can be CC or OC.

 Exercise difficulty is dictated by total target

ROM.

 Eccentric control exercises are commonly prescribed.

 Patellar taping can be helpful.


Summary

 Relationships among lumbopelvic, hip, knee, ankle, foot requires thorough evaluation and treatment.

 Anatomic impairments can predispose the patellofemoral joint to poor tracking and excessive loads.

 Physiologic impairments (mobility, muscle performance, etc.) of neighboring regions can be manifested as symptoms at the knee.


Summary (cont.)

 Examination of patellofemoral joint must include muscle length, joint mobility, etc. at neighboring regions and assessment of patellar position and motion.

 Improvements in impairments and general quadriceps strengthening within the entire lower kinetic chain associated within PFPS may result in positive outcomes.


Summary (cont.)

 Major anatomic impairments at the knee are genu valgum/varum. These postures predispose lateral and medial compartments to excessive loads.

 Physiologic impairments at the knee can be compensated by motion at other joints.


Knee joint

Chapter 21

The Knee

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Chapter 21

The Knee

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