Current Issues in Sports Medicine: The Knee Rob Naber, P.T., O.C.S., A.T.,C. Copyright © 2006 Physical Therapy of Los Gatos. All rights reserved.

The Knee in Sports Medicine

The Knee in Sports Medicine

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

Anterior Knee pain

Anterior cruciate ligament tears in female athletes

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

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

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

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.

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.

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

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

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.

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

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.

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.

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.

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.

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 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

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 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.

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

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

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

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.

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.

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.

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.

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.

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.

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.

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.

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