knee pathology and rehabilitation Flashcards
definition: unable to get full terminal knee extension due to delayed firing of the quadriceps muscles
Quad Lag
What patient population commonly presents with quad lag? Why?
a. TKA
b. weakness of the quadriceps and swelling
What is the prime knee extensor muscle?
rectus femoris
What is the only muscle crossing the anterior axis of the knee?
Quadriceps femoris
What improves leverage of extensor force? How does it do this?
a. patella
b. increases the distance of the quadriceps tendon from the knee joint axis
The physiological advantage of the quads rapidly diminish during the last ____ degrees of EXT due to shortened length (decreased mechanical advantage)
15 degrees
What are the primary flexors of the knee?
Hamstrings
What is the prime function of the gastrocnemius?
Supports the posterior capsule of the knee and avoid hyperEXT (CKC support)
What does the popliteus do?
Knee FLX
supports posterior capsule
Acts to unlock the knee (Screwhome mechanism)
What does the pes anserine do?
Provides medial stability to the knee
affects ROT of the tibia in CKC
Normal gait cycle is about ___-___ degrees of knee FLX.
0-60
What controls the amount of knee flexion during initial contact?
Quadriceps
What normally controls the forward swinging leg during terminal swing?
Hamstrings
You need ___-___ degrees of knee FLX with stairs.
80-100 degrees
What can you see with climbing stairs with a knee pathology?
Hip hiking and circumduction
Referred pain to the anterior aspect of the knee can be from the ___ nerve roots.
L3
Referred pain to the posterior aspect of the knee can be from the ______ nerve roots.
S1 and S2
AROM of the knee is (less/more) than the PROM. Why?
a. less
b. due to joint distention, stiffness, pain, weakness, and reflex inhibition
(CKC/OKC) exercises tend to be less stressful in early management of knee pathology.
CKC
OKC exercises provides less resistance and has less discomfort at (lower/higher) velocities
higher velocities
What does an osteotomy of the tibia provide?
- correcting joint deformity
- redistributing WB forces
- reduces pain
When is knee surgery indicated?
When conservative management cannot control pain and effusion with knee arthritis
definition: shaving of the patellar cartilage
arthroscopic chondroplasy
definition: scraping to the posterior of the patella w/ chondromalacia to induce inflammation/bleeding
Abrasion arthroplasty
How long can a TKA be cemented for?
10-15 years
Why would a cementless arthroplasty require longer periods of immobilization?
to allow bone growth
What muscles should you look to strengthen during the maximum-protection phase of rehab for TKA?
quads, hamstrings, and gastrocnemius
Is vigorous passive stretching appropriate during early post-operative periods?
NO
When can you start performing mobilizations to the patella after a TKA?
2-3 days post-op (may be difficult with staples)
What does WB progression depend on after TKA?
Type of prosthesis
Type of Fixation
What type of WB is almost always indicated after a TKA?
WB as tolerated
With patellectomy, there is a lot of strength lost with what motion?
Knee EXT
The peak torque of quadriceps muscles occur between ___-___% of knee FLX
50-70% (usually about 66)
Patellar compression increases with knee FLX at approx. ____ degrees when WB
45 degrees
What is the normal female Q angle?
17-18 degrees
What is the normal male Q angle?
13-14 degrees
There is usually ___ tract with a grater Q angle
Lateral
Lateral fixation of the patella is provided by what?
IT band, lateral retinaculum
Patellar function is opposed by the medial pull of what?
VMO
The ______ fixates the patella inferiorly.
patellar ligament
The ___ fixates the patella superiorly.
Quadriceps tendon
Where in the knee ROM does the apex of the patella have contact?
20 degrees
Where in the knee ROM does the central portion of the patella have contact?
45 degrees
Where in the knee ROM does the base of the patella have contact?
90 degrees
Where in the knee ROM does the odd facet of the patella have contact?
135 degrees
There is no release of synovial fluid until ____ degrees or more of knee FLX.
135 + degrees
definition: Imbalance in the biomechanics of the PF joint causing breakdown or degeneration in the articular cartilage
patellofemoral dysfunction (patellofemoral pain syndrome)
What is the most common type of knee pathology? What population does it affect more?
a. patellofemoral dysfunction
b. females and/or those with larger Q angles
What are possible causes of patellofemoral dysfunction?
- Larger Q-angle
- Poor VMO control
- Strength
- Recruitment
- Tight lateral retinaculum
- Patella position (tilt, rotation)
- Increased femoral anteversion
- Patella alta or baja (Salvati’s technique: patella tendon - length/patella length should equal 1.00)
- Hamstring and extensor mechanism/tightness
- ITB tightness
What are symptoms of patellofemoral pain?
- Anterior knee pain
- Crepitus (grating sensation, may or may not be painful)
- Giving way sensation which is NOT reflective of a locking mechanism but reflexive inhibition of quads
- INSIDIOUS onset of sx
- Usually BILATERAL
- Increased pain with stairs, greater descending
- Pain may be increased following sitting (positive theater sign)
- Possibly increased swelling
definition: A type of PFD with softening and fissuring of the undersurface of the patella
chondromalacia patella
What facet of the patella is most commonly affected with chondromalacia patella?
Medial facet
chondomalacia patella may be asymptomatic until _____ increases
pressure
What are the s/s of synovitis due to patellofemoral dysfunction?
- pain in retropatellar region and possibly peripatellar or medial patellar region
- Condition is worse with squatting, stairs (descending)
- May present with crepitus
- Usually MINIMAL swelling
- Might find lateral tracking patella, tilted, rotated, patella alta, or baja
What is the treatment of PFD?
- decrease effusion
- increase flexibility of tight structures
- possibly orthotics (control of foot PRON and abnormal motion)
- strengthening
- surgery (patellar shaving, patellar chondroplasty, patellar realignment, patellectomy) – RARE
train hip ER/posterolateral hip
(concentric/eccentric) control has been shown to play an important role in PF function
eccentric control
What is another name for patellar tendonitis?
jumper’s knee
What are the s/s of patellar tendonitis?
- Tenderness to palpation of patella tendon
- c/o soreness with jumping and squatting activities
- Usually MINIMAL swelling if present
- Pain with resistance
Where does the ACL attach?
Attaches medially to anterior intercondylar region of tibia and to posteromedial aspect of the lateral femoral condyle
What are the two bundles of the ACL? What motion causes them to be more taut?
smaller anteromedial (taut in FLX)
posterolateral (taut in EXT)
What motions cause the ACL to become taut?
knee EXT and IR
What are the functions of the ACL?
- Restraint to anterior translation of tibia on femur (85%)
- Assists in restraint of ER of tibia with knee flexed and with valgus stress
- Assists in limiting varus stresses and hyperextension of the knee
What is the most common cause of ACL injuries?
Non-contact injuries from sudden deceleration or a cutting maneuver
ACL injuries from contact are commonly from a combination of ___ and ___ forces applied to the knee w/ the foot firmly placed on the ground.
Valgus and ER forces
*excessive IR forces or a combination of IR and hyperEXT can also cause damage to the ACL
What is the typical presentation of an ACL injury?
- Athlete usually feels or hears a pop at time of injury
- Followed by swelling within one hour
- Acute hemarthrosis within 12 hours
What tests are most reliable for ACL injury Dx? What is the issue with these tests?
Lachman test
Pivot Shift test
–> can produce false negatives due to swelling, muscle guarding, and pain
When does ACL rehab start?
IMMEDIATELY following surgery (in recovery room)
When are patients with ACL injuries allowed to start WB?
day after surgery (WBAT) –> crutches
What type of ROM is encouraged immediately post-op?
PROM (full EXT)
A person with an ACL injury will be in a knee immobilizer after surgery until when?
Until adequate quadriceps contraction
–> will then be put into a ROM brace
When are patellar mobilizations started after an ACL surgery?
First week
Quad strengthening starts during the first week of ACL post-op but only with (CKC/OKC) exercises
CKC
OKC exercises with heavy resistance are held off until weeks __-__ after an ACL repair
6-8 weeks
What is the most important consideration for the first 2+ months after an ACL surgery?
Graft protection
When are grafts the weakest after ACL repairs?
first 4-8 weeks
Isokinetic testing is deferred from ACL repair rehab until week ____.
week 12
Active Total Knee EXT w/ heavy resistance should be avoided for __-__ weeks after an ACL repair.
4-6 weeks
A patellar tendon graft after an ACL repair has ____% the strength of the original ACL at the time of implantation. What causes a decrease in strength of the graft over time?
168%
3 months: 53%
6 months: 52%
1 year: 81%
–> necrosis of the graft and subsequent revascularization
Where does the PCL connect?
Arises from the posterior intercondylar region of the tibia and attaches to the lateral aspect of the medial femoral condyle
What are the bundles of the PCL? When are they taut?
posterolateral (taut with EXT)
anteromedial (taut with FLX)
What are the functions of the PCL?
- limit posterior translation of tibia on femur
- Some control of varus and valgus stresses at knee
- Minimal rotational control
What ligament is referred to as the “key stabilizer” of the knee?
PCL
PCL deficient knees tend to have greater ___ forces and ___ compartment compression.
greater PF forces
Medial compartment compression
What are the typical causes of a PCL injury?
anteromedial force to a flexed knee “dashboard injury”
Posterior force to the anterior/proximal aspect of tibia
slide tackling
PCL injury rehab mimics ACL rehab EXCEPT the_______ are avoided acutely and ___ are pushed early.
Hamstrings avoided acutely
Quads pushed early
What is stronger… autograft or allograft?
autograft
What causes an increased morbidity (patellar tendonitis, exc)… autograft or allograft?
autograft
Allografts can be rejected due to what?
AIDS and HIV
Why are allografts not as strong?
Need to be sterilized and preserved
What is another name for the MCL?
tibial collateral ligament
What are the bundles of the MCL?
Superficial and deep
What are the attachment sites of the MCL?
Proximal attachment: medial femoral condyle, just distal to the adductor tubercle
Distal attachment: medial margin of the tibia, deep to pes ans
The ____ portion of the MCL is firmly attached to the medial meniscus and blends with the medial joint capsule
deep
When is the MCL taut?
Full EXT w/ ER
Avoid ___ and ___ AROM/PROM with an MCL tear.
Full EXT and ER
What are the functions of the MCL?
- Resists valgus stress at the knee
- assists in resisting rotation and anterior-posterior excursion at the knee
What is the common cause of a MCL injury?
a valgus force, with knee in full extension (or < 90° flexion)
What is the unhappy triad?
MCL, ACL, and Medial meniscus
(true/false) Surgical intervention for MCL injuries are rare.
true
What motion should you avoid during acute rehab of a MCL injury?
full knee FLX
What is another name of the LCL?
fibular collateral ligament
What are the attachment sites of the LCL?
From the lateral femoral epicondyle to the head of the fibula
Superior attachment is fused with lateral capsule
What portions of the LCL do not attach to the capsule?
Middle and distal portions
What are the functions of the LCL?
- Resists varus stress at the knee
- assists in controlling ER of tibia
What ligament of the knee is injured less frequently? Why?
LCL because of its location and the rarity of varus forces.
What causes an LCL injury?
Varus stress applied to a fully or partially flexed knee
LCL repair is (less/more) common than an MCL repair.
more common
What motions should you avoid with LCL rehab?
Varus stress and ABD with forces distal to the knee
Autografts and allograft have a (poor/good) success rate.
poor success rate
What are the functions of the menisci?
- Increase joint congruency
- Shock absorption
- Stability
- Lubrication and nutrition of joint
What are s/s of meniscal tears?
- VMO atrophy
- Pain with or without swelling
- “Giving way”
- Locking & unlocking
(+) diagnostic special tests - Joint effusion
- Joint line tenderness
- Blocking at end ranges
What special tests are used for menisci injuries?
McMurray
Apley’s
Bounce Home
Anderson medial-lateral grind
Thessley
Meniscal repair rehab is (less/more) aggressive with strengthening due to tendon and ligament attachments.
less aggressive
After knee surgery the ROM of knee flx is ____ degrees and __-__ degrees of EXT.
80 degrees of FLX
10-15 degrees of EXT
Describe the grading of valgus laxity when evaluating the knee.
Grade I: 5 mm
Grade II: up to 10 mm
Grade III: > 10 mm
Describe the grading of varus laxity when evaluating the knee.
Grade I: 5mm
Grade II: 8mm
Grade III: > 8mm
What is the OPP of the tibiofemoral joint?
20-30 degrees of EXT
___ glide of the tibia assists with EXT of the knee (prone)
Anterior glide (EXT)
____ glide of the tibia assists with FLX of the knee (supine)
Posterior glide (FLX)
___ glide of the patella assists with FLX of the patellofemoral joint
caudal/inferior (FLX)
___ glide of the patella assists with EXT of the patellofemoral joint.
superior/cephalic (EXT)
(true/false) PROM is ok (and necessary) immediately following ACL repair/tear, both extension and flexion
true
(true/false) Full passive extension to zero degrees is ok and encouraged after ACL repair/tear (joint is moved into full extension in surgery room)
true
Active terminal knee extension with moderate to heavy wts. (last 20-30°) should be avoided for the first __-__ weeks after an ACL repair/tear
4-6 weeks
Brace is usually at full ____ acutely following ACL reconstruction
EXT (closed chain)
Avoid terminal ____ both passively and actively to avoid stretching of healing MCL
EXT (last ~10-20 degrees)
–> also avoid full knee FLX acutely
If anterior horn of the menisci is involved: might need to avoid terminal knee _____ acutely and resisted knee _____
terminal and resisted knee EXT
If posterior horn of the menisci is involved: avoid full knee ____
FLX
(and resisted knee flexion if repaired)
Patellofemoral syndrome should acutely avoid excessive _______ to avoid compressive forces of the articular surface of the patella.
Resisted knee FLX
What are the 4 stages of cartilage wear?
- minimal fraying
- 1/4-1/2 tear
- Cartilage almost worn down to the bone and significant crepitus
- bone on bone
At what stage of cartilage wear is there no pain but crepitus is present? Why?
Stage 3
Cartilage is avascular/aneural at that stage
What type of joint is the tibiofemoral joint?
modified hinge
Avoid (FLX/EXT) if the anterior portion of the menisci is damaged
EXT
Avoid (FLX/EXT) if the posterior portion of the menisci is damaged
FLX
Anterior-posterior stability of the tibiofemoral joint is provided by what ligaments?
ACL and PCL
Medial-lateral stability of the tibiofemoral joint is provided by what ligaments?
MCL and LCL
Where is the femoral condyle longer? Why?
medial
contributes to locking mechanism of the knee
What tibial plateau is larger?
medial
What structures does the medial meniscus attach to?
joint capsule (coronary ligaments)
semimembranosus
ACL
MCL
The patella engaged in motion between __-___ degrees.
60-90 degrees