Chapter 21 The Knee

Copyright 2005 Lippincott Williams & Wilkins

Chapter 21The Knee


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 Flexion0–90 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 EvaluationComponents 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 techniquesPatellar mobilizationQuadriceps, hamstring stretchesAbdominal 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 diseaseMSParkinson’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.

Chapter 21 The Knee

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