1. Mary Thurtle, SPT
University of Washington
Knee Osteoarthritis (OA): Muscle Performance
Impairment: Poormuscle performance can worsen symptoms and hasten the progression of knee OA. Mechanical
stresses and/or immobilization result in a lackof synovialfluid nutrients, cartilage deterioration, faulty joint
architecture, and osteocyteformation1. These changes can cause postural impairments, functionalADL limitations,
diminished physical fitness, and constant joint pain in advanced stages, resulting in limited participation and poor
quality of life1.
TreatmentGoals:
1. Improve LE strength, endurance, and power1,2
2. Reduce pain2
3. Reduce disability1
ExerciseApproach:Progressiveresistance exercises, functional exercise, aerobic exercise
Rationale/Theory:Improvingstrength, power, and endurance of hip, knee, and ankle musculature willprotect the
knee by attenuating joint impact, increasing stability, and improving joint alignment thus slowing, stopping, or
reversing the progression of mechanical deformation at the joint margins1,3.
Precautions:
 Increased pain
 Form failure
 Valsalva maneuver1
Contraindications:
 Baker cyst rupture/hemorrhage (severe pain and distal swelling)2
 Max resistance through painful arc1
 Kneel, half-kneel without cushion/padding4
EXERCISES5: Increaserepetitions at the given resistance level before increasing resistance.1
ResistanceExercise:Targethip
stabilizers (gluteus maximus, gluteus
medius, rotators) and knee stabilizers
(quadriceps, hamstrings)1
Functional Exercise:Activities1 and 2 can be
done withan assistive deviceor in a pool if
weight bearing is painful1
AerobicExercise1,6
1. Multiple-angle isometrics in 7 pain-
free positions using free weights1:
50% 1RM, 8 sec per position, 2 sec
rest in between positions, 2 sets, 2
min rest between sets, 3x/wk
2. Straight leg raises in all planes with
minimal stress on knee joint
structures: 10 reps, 3 sets, 2 min
rest between sets, 3x/wk
3. PRE program: 60-80% 10 RM, 10
reps, 3 sets, 2 min rest between
sets, 3x/wk3
1. Sit  stand progressing from wallslides to
mini wall sit to high chair with armrests to
standard height chair: 6 reps, 2 sets, 5 min
rest between sets, 1x/d
2. Step-up/downs in a relatively pain-free
range; progress step from short  tall, using
arm support to offloadforces: 10 reps, 2 sets,
2 min rest between sets, 1x/d
3. Partial lunge in a relatively pain-free range,
progress to lifting items off the floor:10 reps,
2 sets, 2 min rest between sets, 1x/d
1. Walk or bike at
low resistance3:
60% max HR, 20
min, 4x/wk
2. Aquatic therapy:
walk,jog, or swim
in the pool if
weight bearing is
not tolerated on
land: 60% max HR,
20 min, 4x/wk
Considerations3:
 Early morning therapy including strenuous activity or weight bearing1
 Patient’s functionalstatus: age, general mobility, OA stage, comorbidities1,2
 Patient’s mental health, self-efficacy,and social support1
 Individualized to patient’s functionalgoals, pain tolerance, and existing radiologically damaged structures to
promote optimum adherence to HEP after discharge1
References:
1. Kisner C, Colby LA. In: TherapeuticExercise: Foundations andTechniques. 6th ed. Philadelphia, PA: F.A. Davis Company; 2012.
2. Goodman CC, Fuller KS. In: Pathology: Implications forthePhysicalTherapist. 3rd ed. St Louis, MO: SaundersElsevier;2013.
3. Roddy AE, ZhangW, Doherty M, et al. Evidence-based recommendations fortheroleof exercisein themanagement of osteoarthritis of thehip or knee—the
MOVE consensus. Rheumatology. 2005;44(1):67-73.
4. O'Sullivan SB, Schmitz TJ. In: ImprovingFunctional Outcomes in Physical Rehabilitation. Philadelphia, PA: F.A. Davis; 2013.
5. ZhangW, Moskowitz RW, Juki G, et al. OARSI recommendationsfor themanagement of hip and kneeosteoarthritis, Part I: Critical appraisal of existing
treatment guidelines and systematic reviewof current research evidence. Osteoarthritis and Cartilage. 2007;15(9): 981-1000.
6. Rowdy E, Zhang W, Doherty M. Aerobic walkingor strengtheningexercisefor OA of theknee? A systematic review. Ann RheumDis. 2005;64(4): 544-8.

2. Mary Thurtle, SPT
University of Washington