Current Issues in Sports Medicine: The Knee

The Knee in Sports Medicine

Current challenges in Sports Medicine
Anterior Knee pain
Anterior cruciate ligament tears in female athletes

Etiology
Unknown
Debated Frequently
Two theories:
Chondromalacia
Malalignment of patella and femur

Optimal Knee Mechanics
Patellofemoral articular cartilage thickest in the body
Allows almost friction free motion between patella and femur

Chondromalacia
Softening and degradation of retropatellar cartilage
Degraded cartilage results in increased friction and shear forces
Physical Therapy is directed at improving strength of the quadriceps in positions that minimize compression of patellofemoral joint

Chondromalacia Evidence
Rehabilitation has not been shown to provide long term relief.
Scott Dye, MD, probed his own knee without anesthesia, and discovered no sensation in the cartilage of his diseased articular cartilage.
Presence or absence of chondromalacia does not predict knee pain.

Malalignment
The patella is somehow skewed or is located too far to one side within the femoral trochlea, causing excessive compression and pain.

Treatment for Malalignment
Tape applied to the skin to hold the patella in a corrected position.
Braces to correct patellar position

Treatment for Malalignment
Specific and selective muscle training exercises aimed at changing the position of the patella.
Specific muscle training exercises aimed at changing the position of the femur.
The Track and the Train Theory

Malalignment Evidence
Malalignment does not predict whether an individual will experience anterior knee pain.
Evidence to support long-term benefits of non-surgical treatments for patellar alignment is limited and inconclusive.

Therefore:
Neither Chondromalacia nor Malalignment are sufficient to cause anterior knee pain alone.
Suggest a plurality of causes
Chondromalacia
Malalignment
Quadriceps eccentric strength deficits

Quadriceps Function
Primary function according to the anatomy texts is extension of the knee.
In standing and walking, the quadriceps work eccentrically to control knee flexion.

Evidence for Eccentric Training
Bennet and Stauber 1986.
Observed the ratio of eccentric quadriceps torque to concentric torque was not normal in group with anterior knee pain.
Expected eccentric torque 130%-300% of concentric torque, but those in study were deficient.
Most patients’ pain was relieved with eccentric training of the quadriceps within 2- 4 weeks.

Eccentric Training
KIN-COM Training
Decreased motor unit recruitment with eccentric contraction.

Eccentric Torque Curve Pre-treatment Post-treatment

Eccentric Training in the Clinic
Easily accomplished without expensive computer dynamometers.
The resistance needed can be generated through the use of gravity and therapist’s resistance.

Eccentric Training in the Clinic

Patellofemoral Contact
Patellofemoral contact area changes
Increases in area with flexion
Moves from distal to proximal with flexion

Patellofemoral Contact

Patellofemoral Contact Moves Proximal with Flexion

Patellofemoral Compression as Provocation Test

When Compression is Painful
Consider the specific location of athletes pain: Patella or Femur
Protect the patellar contact during strengthening phase
Use appropriate open vs. closed chain strengthening exercises

Conclusion
Anterior knee pain arises from multiple causes
Multi-pronged rehabilitation strategies offer the greatest likelihood of returning patients and athletes to their pre-symptom state.

Anterior Cruciate Ligament Tears in Female Athletes

Anterior Cruciate Ligament Tears- The Problem
One of 10 female athletes will suffer an ACL injury
10,000 knee injuries per year
Rate of knee injury in female athletes is 3.7 times greater than males.

ACL Anatomy
One of four of major ligaments in the knee.
ACL intersects all three planes and provides stability in all three planes.
Controls femoral roll and slide on tibia

ACL anatomy

Hypotheses to Gender Differences of ACL Tears
Hormones cause ligament laxity
Smaller intercondylar notch size
Differences in lower extremity strength and neuromuscular control

Differences in Lower Extremity Strength and Neuromuscular Control
Hewett, et al. showed female athletes with greater valgus alignment during jumping and landing are more likely to suffer an ACL injury.
Noyes demonstrated male and female athletes had similar excessive valgus alignment.
Female athletes have weaker hamstrings
A 6-week training program could correct the valgus alignment.
Hewett TE, et al. Am J Sports Medicine 2005;33(4):492-501 Noyes, et al. Am J Sports Medicine 2005; 33(2):197-207

Implication for Rehabilitation
Muscular strength stabilizes knee
Muscular attachments to ligament, tightens ligament upon contraction.
Include training to avoid valgus loading.
It is no longer acceptable to reconstruct the ACL but leave neuromuscular control deficient.

Creating Rehabilitation Program
Consider mechanism of injury
Reactivity of patient’s symptoms
Stage of healing
Match appropriate treatment and dosage.

Ligament Healing
Inflammatory Phase- Day 0-3 hematoma and inflammation seen; macrophages clear necrotic tissue
Reparative Phase- Day 3 fibroblasts lie down scar tissue; Day 14 fibroblasts predominant and vascular network forming.
Remodeling Phase- 12 months or more, ligament strength 50-75% of control.

Jump Strength Training Program
Based on Hewett’s successful program.
Element of ACL reconstruction rehabilitation
Stand alone performance improvement module
Includes jump analysis, education, strength training and neuromuscular training.

Neuromuscular Training
Includes visual, auditory and proprioceptive facilitation to give the athlete the tools to correct faulty lower extremity alignment during jumping, landing and pivoting and use their muscles to absorb impact.

Conclusion
ACL tears are significant in all athletes
Lack of neuromuscular control is a risk factor for injuries to the ACL, especially in female athletes
Male and Female athletes demonstrate excessive valgus alignment
Young athletes can learn to gain this control.

www.PTofLosGatos.com (408) 358-6505

http://www.webicina.com	25
http://www.cafemedicine.com	19
http://www.slideshare.net	8
http://tofw-bookclub-sanantonio6.blogspot.com	1
http://localhost	1
http://www.peharec.com	1
http://learn.valenciacollege.edu	1

Current Issues in Sports Medicine: The Knee

by cyclicamp on Feb 11, 2007

Accessibility

Categories

Tags

Upload Details

Usage Rights

7 Embeds 56

Statistics

Current Issues in Sports Medicine: The Knee — Presentation Transcript