Orthopedic Management of the Knee Flashcards
References
Kisner and Colby, Chapter 21
Shankman, Chapter 18
fyi
The knee joint is designed for mobility and stability
What are some other things?
- It lengthens and shortens the LEs to raise and lower the body or to move the foot in space
- Supports body when Wbing
- Primary functional unit in walking, climbing and sitting activities
- The rotation that occurs between the femoral condyles and the tibia during the final degrees of extension is called ?
- When tibia is fixed, terminal ext results in the femur rotating internally
- As the knee is unlocked, the femur rotates laterally
locking
or
screw home mechanism.
If a patient lacks full hip extension (as with a hip flexion contracture), the patient cannot stand upright and lock the knee, thus lacking this passive stabilizing function?
the screw-home mechanism
- The primary function of the this is to increase the moment arm of the quadriceps muscle in its function to extend the knee.
- It also redirects the forces
the patella
The alignment of the patella in the frontal plane is influenced by what two things?
- line of pull of the quadriceps muscles group
- attachment to the tibial turbercle via the patella tendon.
the line of pull of the quadriceps muscles group and by its attachment to the tibial turbercle via the patella tendon.
The result of these two forces is a bowstring effect of the patella, causing it to track in which direction?
laterally
Increased Q angle occurs from ?
- wide pelvis
- Femoral anteversion
- Coxa vara
- Genu valgum
- Laterally displaced tibial tuberosity
Motions in transverse plane that may increase Q angle:
- External tibial rotation,
- Internal femoral rotation
- pronated subtalar joint
Functional knee valgus that occurs during dynamic activities can also?
increase Q angle
IT band and lateral retinaculum prevent ?
medial gliding of the patella
Tight ankle PF causes?
lateral displacement of the tibial tuberosity in relation to the patella
Do Tight HS muscles affect mechanics of the knee?
yes
what is VMO stand for ?
vastus medialis obliquus
Weakness or poor timing of VMO contractions increases?
the lateral drifting of the patella
Weak hip Abductors and External Rotators may result in ?
adduction of the femur and valgus at the knee under loaded weight bearing
During the normal gait cycle, the knee goes through a range of?
60 degrees (0 degrees extension at initial contact and 60 degrees at the end of the initial swing.
Muscles involved in knee control during gait:
- quadriceps
- hamstrings
- soleus
- gastroc
Because the knee is the joint between the hip and the foot, problems in these areas (hip/foot) can interfere with knee function. What are some problems?
- Hip flexion contractures
- Length and strength imbalances
- Foot impairments
Name the knee ligaments
- ACL
- PCL
- LCL
- MCL
- meniscus
If needed, review ligament healing in Shankman (Chapter 8)
fyi
- Injury often results in joint effusion
- Often referred to as “water on the knee” or “fluid in the knee”
ACL Tear-An intracapsular ligament
- Often non-contact
- Rotation of the tibia on a planted foot
- Can occur from forceful hyperextension
- Lateral blow to the knee (valgus force)
- Often occurs “terrible triad” or “unhappy triad”
ACL Tear’s MOI (Mechanism of Injury):
ACL Tear-S & S (signs and symptoms)
- Swelling
- Pain
- Instability (+ Lachman + anterior drawer)
Pg 293, Shankman
What test
- Patient supine
- Knee flexed to 25-30 degrees
- Stabilization of the femur with one hand and anterior/posterior translation of the proximal tibia with other hand
- Translation of the tibia should be less than 5 mm
- A 5mm-10mm translation is a (+) sign for ligament instability
Lachman
What test?
- Less reliable because ligament is relatively relaxed at 80-90 degrees of knee flexion
- Testing position
- Patient supine; knee flexed to 90 degrees
- Stabilization of affected limb by therapist sitting on foot
- Proximal tibia grasped with both hands with thumbs at the anterior joint line
- Anterior/posterior translation of proximal tibia
- Translation should be less than 5 mm
- A 5mm-10mm translation is a (+) sign for ligament instability
Anterior drawer test
ACL Tear-Conservative treatment
- Joint protection
- Activity modification
- Treat inflammation
- Exercise
If conservative treatment fails, patient typically requires?
surgical repair
- Tissue used from the body of the patient.
- Gracilis tendon, fascia lata, Semi-T tendon, and the quadriceps muscle tendon.
- The bone-patellar tendon-bone autograft is the strongest one used for ACL reconstructions
Autograft
- Biologic tissue taken from another human body
- Risk of disease transmission and problems with effective sterilization techniques
Allograft
talk through Graft healing
- First 6-8 weeks, a gradual process of avascular necrosis occurs
- Graft typically quite fragile during the first 2 months after surgery
- Following 8 weeks, revascularization begins
- At 3 months (12 weeks), graft is typically less than 50% of its original strength
ACL Repair- Exercise precautions/considerations
- No open chain extension from 40 degrees of knee flexion to 0 degrees b/c of tensile forces on the ACL (passive terminal knee extension is permitted)
- Note: Text states that active flexion-extension motion of the knee from 35 degrees to full flexion as part of a research based protocol
Greatest amount of stress on graft occurs between?
20 degrees of knee flexion and full extension
how long is Maximum Protection Phase for the knee?
(Day 1 through week 6)
for ~2 weeks,-Generally locked in ext or 10 degrees of flex and WB 25-50%
after 2 weeks-0-90 degrees
3-4 weeks-FWB
Maximum Protection Phase (Day 1 through week 6)
WHAT PHASE?
- Emphasize control of swelling
- How?
- Encourage quad control and HS strength
- Begin strengthening and ROM within precautions
- Get extension ROM
- Quad sets, HS sets, hip strengthening, calf muscle strengthening, patellar mob, gait training
- Closed chain exercises with brace on
- Within ROM limits
Maximum Protection Phase
To transition to moderate protection phase activities, the following criteria should be achieved:
- PROM 0-120 degrees of flexion
- Full to close to FWB
- Quad and HS control
- Controlled pain and swelling
- Minimum of 6 weeks from day of surgery
- 6-8 weeks, graft is weakest. Use caution!
- Short arc leg press (in brace)
- CKC (Closed Kinetic Chain) exercises within precautions
Moderate Protection Phase (week 7-12)
- 3 months post op, if muscles are strong and ROM is full, pertubation training
- More functional exercises
Minimum Protection Phase (beyond week 12)
MOI:
Forceful blow to the anterior tibia when the knee is flexed
Dashboard, fall
PCL Tear
S & S
- Godfrey tibial sag test
- Pain
- Swelling
PCL Tear
Patient is supine
Hip and knee of the affected limb is held at 90 degrees
Hold the heel of the affected limb and allow tibia to translate, sublux or sag posteriorly by gravity
See fig 19-17, Shankman (pg 302)
Godfrey tibial sag test
No open chain HS curls (posterior translation of tibia)
Patient may need to be braced to prevent too much knee flexion
PCL Exercise Precautions
Conservative treatment for what ?
- Joint protection
- Activity modification
- Treat inflammation
- Exercise
- If this fails, patient will have surgery
PCL tear
Rehab following surgery
- WB progressed very slowly
- Some sources advocate limited FWB for 4-6 weeks or longer
- Some sources advocate initial Wbing with no greater than 50-60 degrees of knee flexion
PCL TEAR
PCL Repair-Max protection phase (post op-12th week) EXERCISES?
- Early isometrics
- CKC for quadriceps
PCL repair-Moderate protection phase (13-24th week)- where ya at?
Progression of CKC exercises
PCL tear- Minimum protection phase (beyond 24th week)
where ya at?
Returning patient to pre-injury functional state
MOI:
Valgus force against the medial joint line
what ligament is injured?
MCL
Treatment: for what ligament if injured?
RICE
Physical Therapy
Strengthen and gain compensatory stability with muscles
MCL
MOI
Traumatic varus force across knee
Can occur with joint capsule and lateral meniscus
Treatment
RICE
Physical therapy
Strengthen and gain compensatory stability with muscles
?
What ligament is injured?
MOI:
- Fixed tibia, rotation of femur
- Degeneration plus relatively normal force, squatting, getting out of the car
- Medial torn more often than lateral
Meniscus Tear
S & S
“Locking” of the knee
Pain with Wbing
Swelling
Meniscus Tear
Meniscus Tear-Surgery
- Partial or total meniscectomy
- Typically arthroscopic
- Indicated if avascular part of meniscus is torn
- Most vascular portion of meniscus is peripheral 10-30%
- OP surgery unless person has complex medical status
Meniscus Tear-Post-op PT
- WB precautions vary
- TTWB at first, full by 6-8 weeks
- Initial brace locked in extension
- Ice and elevate
- ROM and strengthening within precautions
- Gait training
Meniscus Tear-After 3 months
- Protection of surgery significantly decreases
- CKC exercises progress
- Balance
- Return to activity/functional training
S & S
Often reports of anterior knee pain
Anterior knee pain often caused by mechanical deviations of patellar tracking
Patellofemoral Pathological Conditions
What causes mechanical deviations of patellar tracking?
- Tight IT band & HS
- Weak quad
- LE bony alignment
- Large Q angle
- Chondromalacia
PT Treatment for what?
Stretch and/or strengthen to overcome impairments
Consider how each exercise will benefit the patient
PT should assess what is going on at the ankle/foot as well
Patellofemoral Pathological Conditions
- Often referred to as DJD
- Most common disease affecting Wbing joints
- 1/3 of individuals over 65 years of age have radiographic evidence of OA
- Deformities commonly develop
OA
Treatment for what?
Joint protection
Increase ROM
Increase strength
OA
- Widely performed procedure for advanced arthritis of the knee
- Usually performed on older patients with OA
- However, TKA performed on younger patients has increased
Total Knee Replacement (TKR) Total Knee Arthroscopy (TKA)
Two types of implants are used:for TKA
- Constrained
- Nonconstrained
- Also known as conforming implants
- Significant congruency of the components
- Offers most stability, but considerable limitations of motion
Constrained
- Also known as resurfacing implants
- No inherent stability in the implant design
- Used primarily with unicompartmental arthroplasty
Nonconstrained
Max protection phase-TKA
- Reducing stresses that may loosen the prosthesis
- Stimulate muscle strength
- Increase ROM
- Reduce pain
- Reduce inflammation
- Gait training
- Transfer training
- Education
Moderate protection phase-TKA
- Progress gait training
- Patella mobs
- Scar mobilizations
Minimum Protection Phase-TKA
- Progress to isotonic knee extension exercises
- Isokinetic knee flexion and extension
- Stationary cycling for improved knee ROM
- Various CKC functional activities
- Walking, stair climbing
- Balance training
