KNEE

OSTEOARTHRITIS
 DEFINITION
Knee osteoarthritis (OA), also known as degenerative joint
disease, is typically the result of wear and tear and
progressive loss of articular cartilage.
 Osteoarthritis predominantly involves the weight- bearing
joints, including the knees, hips, cervical and lumbosacral
spine, and feet. More correctly called osteoarthrosis
because it is not inflammatory condition.
It is a degenerative joint disease involving the different
structures of the joint. The degradation of joints, including
articular cartilage and subchondral bone. But also ligaments,
the capsule and the synovial membrane degenerate.
It never be reversed.
OSTEOARTHRITIS VS RHEUMATOID ARTHRITIS
Osteoarthritis Rheumatoid
- Asymmetrical Arthritis

- Joint pain, stiffness - Autoimmune

- Pain is worse with use - Symmetrical

- Boney enlargement - Joint pain, swelling,

stiffness, fatigue
- Weight bearing joints
- Joint space narrowing
Risk Factors
1-Obesity Increases pressure on the knees. Every pound of weight you gain adds 3 to 4
pounds of extra weight on your knees. Obesity also increases circulating level of chemical
substances such as leptin, C-reactive protein, and other pro-inflammatory cytokine that may
promote cartilage matrix degeneration.
2-Weak muscle, poor knee Stability and abnormal mobility: due to ligamentous
laxity or poor mobility and proprioception.
3-Gender: Females are more affected.
4-Repetitive stress injuries: usually a result of the type of occupation and athletics: as in
soccer, tennis, or long-distance running.
5-Overuse and underuses: As both cause improper nutrition to the hyaline cartilage.
Pathogenesis of OA
The pathogenesis of knee OA have been linked to biomechanical and biochemical changes in
the cartilage of the knee joint.
In OA, the cartilage decreases in thickness and quality, it becomes thinner and softer,
cracks may occur and it will eventually crumble off. Cartilage that has been damaged, cannot
recover. Finally the cartilage will disappear. The cartilaginous tissue is not the only one
involved.
Given its lack of vasculature and innervation, the cartilage, by itself is not capable of
producing inflammation or pain at least on early stages of the disease.
Hence, the source of pain is mainly derived from changes to the non- cartilaginous
components of the joint, like the joint capsule (degenerated and inflamed), synovium
(synovial effusion), subchondral bone (the bone will expand and spurs (osteophytes),
ligaments (laxity of the ligaments), and peri-articular muscles (muscle atrophy).
Common sources of pain near the knee are anserine bursitis and iliotibial band syndrome.
Most of these are not visualized by the x-ray, and the severity of x-ray changes in OA
correlates poorly with pain severity..
CLINICAL FEATURES
• Pain
• Muscle spasm Stiffness
• Inflammation
• Loss of ROM
• Capsular pattern
• Muscular inhibition & atrophy
• Joint instability
• Crepitus Deformities
• Reduce function
1.PAIN
It is often most immediate importance to the patient
Worsen at night - due to raised pressure in subchondral bone (Often raised
with movement & relive with rest)
Many structure may give rise to pain in OA
• Periarticular soft tissue- capsular/ligament strain
• Muscular pain & weakness
• Inflamed & overstretched synovium
• Refer pain from spine
• Inability to cope
2. MUSCLE SPASM
It is a protective mechanism
Movement cause pain so the body attempts to stop
Movement But prolong spasm cause pain due to metabolic
accumulation & fatigue.
Adaptive shortening may also occur in muscles.

3. STIFFNESS
Probably deprivation of normal movement
Subchondral micro-fractures heal & callus forms, this cause loss of
joint mobility & stiffness
5. INFLAMMATION & EFFUSION
It is not always present unless the joint is underwent over activity
Sign & symptoms includes are -
• Heat
• Erythema
• Tenderness
• Effusion
• Discomfort &Pain.

6. LOSS OF RANGE OF MOTION

Combination of joint pain, stiffness & possible effusion will often cause
limitation of end ROM
Certain joint may develop capsular pattern with restriction in certain ROM
7. MUSCLE INHIBITION & ATROPHY
Effusion will inhibit surrounding muscle of joint. Chronic muscle inhibition is
often linked to chronic pain & will lead to atrophy & ensuring weakness.

8. CREPITUS
The flaked cartilage & eburnated bone end grate against each other
characterized sound.
Mild cracking - indicate synovitis
Loud cracking - indicate advance disease
9. JOINT INSTABILITY
Surrounding muscle weaken & imbalance
Pain episodes are unpredictable causing joint to give away.
These process together with chronic stretch of soft tissue will alter joint alignment.
These will lead to instability & possibly subluxation

10. DEFORMITIES
Osteophyte development reduce joint instability by increasing the peripheral articular
surface area.
Such deformities are more profound in established OA but may not developed equally on
medial & lateral.
This may contribute to varus & valgus deformities Together with the soft tissue laxity, it
will alter normal joint biomechanics.
MUSCLE
IMBALANCE IN
BOW LEG
(GENU-VARUS)
MUSCLE
IMBALANCE IN
KNOCK-KNEE
(GENU-VALGUS)
REDUCE FUNCTION
All the clinical features described above can result in functional
difficulty.
Often described problems are - walking a distance, climbing
stairs, getting out of chair, writing, opening jars etc.
But most patients compensate by alternative ways of achieving the
task.
RADIOGRAPHIC FINDING
X-ray changes -
• Loss of joint space
• Sclerosis
• Altered bone end shape
• Osteophytes
ROLE OF KNEE LOADING IN OA
Knee loading plays a major role in OA knee development and progression.
During the stance phase of gait, high loads are applied to knee in both sagittal and frontal
planes.
The most relevant load is the external knee adduction moment (AM) in the frontal
plane generated because the ground reaction force vector (GRFV) passes medial to the
joint center.
This moment forces the knee laterally into varus & is resisted by an internal abduction
moment, resulting in compression of the medial joint compartment & stretching of the
lateral structures.

The AM influences the load distribution between the medial & lateral plateaus.
The higher the AM the greater the load on the medial plateau relative to the lateral
plateau. Importantly, the AM during gait is a factors known to predict OA progression in
humans.
Management Of Knee OA
It has been found that the optimal management of OA requires a combination of non-
pharmacological and pharmacological modalities.
1-Medical treatment:
• NSAIDS: Used to relieve pain and inflammation for more advanced cases,
however, it has side effects.
• Intra-articular injections of corticosteroids.
• Topical and injectable medications.
• Glucosamine and hyaluronic acids: Acts as a lubricant and shock absorbing,
helps rebuild cartilage.
2-Surgical Treatment (when conservative treatment failed):
• Osteotomy: Performed to change bone alignment and alter load on joint surface and
correct deformities.
• Arthroplasty: Joint replacement can relieve pain and restore loss of function for patients
with advanced disease.
- Uni-Condylar/Compartmental Arthroplasty -Total Knee Arthroplasty
 Physical Therapy Management
Assessment:
➢ ROM.
➢ Muscle Strength.
➢ Joint stability.
➢ Proprioception
➢ Posture.
➢ Gait and Function.
➢ Psychological status.
Aims Of Physical Therapy Treatment:
• Decrease load on the joint.
• Decrease pain, inflammation and swelling.
• Increase mobility and ROM.
• Improve muscle strength and endurance.
• Improve joint stability and proprioception.
• Prevent or minimize deformity formation.
• improve function and independence in ADL.
• Improve Gait.
➢ To decrease the load
1-Weight reduction
Weight increases load on joints. Losing weight directly decrease the load on joint by
decrease the joint reaction force during weight bearing and activities. During ambulation, 3
to 5 times the body weight passes through the knee joint, small changes in weight result in
large increase in force across the joint.
Weight reduction could be achieved either by exercises and/or diet.
2-Walking aids
Assistive devices like canes, crutch and walkers to increase the base of support and decrease
load. Provide effective unloading of the knee and hip when held contra lateral side.
Increase joint stability Frames or wheeled walkers are preferable for those with bilateral OA.
Walking aids is highly recommended. (The cane is held in the hand contralateral to the
affected limb and moves together with the affected limb).
➢ To decrease pain
1-TENS, Interferential.
TENS as it has some evidence to show it can help with pain reduction, so it is recommended.
2-Ultrasonic: It has an anti-inflammatory effects and also serves to improve the extensibility
of the capsule. Usually used in pulsed mode.
3-Electromagnetic field and laser
4-Cryo and thermotherapy: The use of cold therapy is recommended to some extent
during acute flare with minor inflammation.
The use of heat therapy is not recommended as there is no scientific evidence that heat
therapy improve patient symptoms.
5-Massage therapy: Massage temporary relieve pain, reduce tension and
improve circulation, Massage therapy is not recommended as standard treatment.
➢ EXERCISE
(In painful episodes ) :-
Isometric exercise
 Non-weight-bearing exercise
(OCK) e.g., biking, rowing with
adapted tools
 Partial weight-bearing exercises
(CKC) e.g., aquatic exercises
should be recommended.
In painless (or less painful)
periods -
The exercise program may include
progressive muscle performance
exercises.
STRENGTHENING SPECIFIC MUSCLES
Quadriceps Muscle Strengthening –
Muscle weakness (particularly quadriceps) is a well- recognized impairment in people with
knee OA. It has been associated with increased pain & a greater deterioration in function
over time.

Hamstring Muscle Strengthening –

Weakness of the hamstring muscles has been found in patients with knee OA.
Control of varus-valgus laxity is largely produced by co-contraction of the quadriceps &
hamstring muscles. An increase in hamstring strength was associated with less deterioration
in function in people with knee OA.
Hip Abductor Strengthening (Frontal plane mover):-
Strengthening the hip Abd muscles controlling pelvic position in frontal plane may
reduce knee loads and slow disease progression.
Weakness of hip abductor :-
• Drop in the level of the pelvis,
• Shifting the center of mass (COM)
• Increasing the knee AM.
Strengthening abductor muscles could reduce knee load by increasing toe-out during gait
Strengthening of hip extensor (Sagittal plane mover)
Hip extensor muscle play an important role in dynamically stabilizing hip & pelvic in
sagittal plane.
The gluteus maximus act as a restraint for forward progression during gait.
It also helps to minimize deformity in sagittal plane.
■ E.g. hip & knee flexion deformity
Strengthening should consider both short & long lever
➢Joint Mobilization (grade I, II):
• Knee mobilization (anterior-posterior)
• Patients with symptomatic knee OA may
benefit from hip mobilizations (caudal glides-
anterior-posterior glides-posterior-anterior
glides- posterior-anterior glides in the FABER
position),
if they have two or more of the following criteria:
(1)hip or groin pain or paresthesia
(2) anterior thigh pain
(3)passive knee flexion less than 122 degrees
(4)passive hip internal rotation less than 17
degrees
(5) pain with hip distraction.
➢To improve mobility and ROM:
1-Active free ROM exercise within painless ROM
Help in joint nutrition and washing out of pain metabolites by enhancing the
synovial fluid circulation.
2-Joint Mobilization grade III , IV and distraction (anterior, posterior glide).
3-Stretching exercise for tight muscles: (Hip adductors, Hip Flexors,
Hamstring, Quadriceps, Calf, Iliotibial band).
➢ To improve Proprioception,
Functional and gait training:
1-Proprioceptive exercise:
Reduced proprioception in older adults may be
responsible for the initiation or advancement of
knee degeneration.
2-Balance exercise.
3-Under water walking and closed
kinematic chain exercises
➢ Aerobic exercises (low impact):
e.g. tolerate stationary bike.
Aerobic and cardiovascular exercises such as aerobic walking has been shown
to increase strength, improve pain, and cardiovascular condition as well as the
overall function.
These types of exercises are effective in OA treatment though it is less cost-
effective compared to other methods.
➢ Aquatic exercise
is preferable due to low impact and decreased weight bearing on the joints.
It may readily tolerated and less likely to flare symptoms.
Is a non-invasive therapeutic intervention that is recommended in international
guidelines.
Many consider water-based exercises as a good preparation of exercise ashore.
Gait retraining
During acute episodes of pain, patients could be taught simple
biomechanical strategies to reduce knee joint loading. However,
these are temporal procedure, prolonged usage of some of these
methods may cause muscle tightness, increase energy expenditure
during walking and abnormal walking pattern as well as other
problem such as low back pain or scoliosis. Thus, these methods
are not recommended as treatment procedures except in
acute episodes. They mostly reduce ground reaction force on the
medial knee and hence reduce pain.
Among these strategies

A-Increase toe out by voluntarily rotate the feet externally. Out-

toeing during walking shifts the ground reaction force vector closer
to the knee joint center and thus reduces the GRF moment arm to
the knee joint center and knee adduction moment.
B-Reducing walking velocity is also expected to reduce the GRF
and hence joint loading. Thus walking slowly could be an appropriate
life style modification.
 Lose weight to reduce load on the joints.
Advices Modification of lifestyle and daily routine.
to the Not to put the joint in extremes of range.
patient Not to stand, sit or lie in a fixed position for long periods.
Use walkers, crutches or canes during outdoors walking.
Drinking enough amount of water.
Eat healthy food rich in fibers.
Not to be exposed to extreme weather or temperature changes.
Avoid high impact sports & activities as jumping &stair climbing.