Knee injuries Flashcards
What is the pes anserinus?
The conjoined tendons of three muscles that insert onto the anteromedial surface of the proximal tibia:
- sartorius
- gracilis
- semitendinosus
What is used as a graft for ACL repair?
Patella tendon (can use hamstring for younger athletes)
What is the name of the point of insertion for the IT band on the lateral thigh?
Gerdy’s tubercle
Smooth facet on the lateral aspect of the tibia
adjacent to tibio-fibular joint and just below knee
Name the main lateral structures of the knee from superficial to deep layers
- LAYER 1: IT tract, biceps femoris
- LAYER 2: Patellar retinaculum
- LAYER 3:
- SUPERFICIAL: Anterolateral ligament, LCL + fabellofibular ligament
- DEEP: Arcuate ligament, coronary ligment, popliteus tendon, popliteofibular ligament, capsule
Superficial lateral structures of the knee
IT tract, biceps femoris
Layer 2 of lateral structure of knee
Patellar retinaculum
Layer 3 of lateral structure of knee
SUPERFICIAL:
- LCL
- Fabellofibular ligament
- Anterolateral ligament
DEEP:
- arcuate ligament
- coronary ligament
- popliteus tendon
- popliteofibular ligament
- capsule
Layer 1 of medial knee structures
LAYER 1
- sartorius and fascia (patellar retinaculum)
LAYER 2
- semimembranosus
- superficial MCL
- posterior oblique ligament
LAYER 3
- Deep MCL
- capsule
- coronary ligament
Origin and insertion of the MCL
Originates posterior to the medial epicondyle
Inserts 1-6cm along medial aspect of tibia
ACL rupture is likely to be associated with which other injury?
lateral meniscus tear
Ddx traumatic/atraumatic knee pain
What questions do you ask about the knee symptoms? (and common ddx)
- Pain (VAS, upstairs PFP, twisting menisci)
- Instability (ACL, PCL)
- Mechanical Sx (meniscus bucket handle – goes into the notch in the middle/loose body)
- Stiffness
- Swelling
How can different types of instability suggest different ddx?
- Pivoting, twisting, cutting = ACL
- Linear instability - quad weakness
- Side-to-side = PCL
Mechanical knee symptoms and common ddx
locking, clicking, snapping
- menisci
- loose body
relevant questions to ask in Hx
- Treatment received pitch-side –> date
- Benefits of previous Tx
- Athletic Hx, level of play/hours, skill level, goals
- Type of sport
- PMHx/review of Sx
- Occupational Hx
Sequence of knee examination
1- inspection
2- palpation
3- ROM, strength
4- Patella- tilt, apprehension, translation, crepitus, J-sign, Q-angle
5- Meniscal tests
6- Ligamentous stability- drawer, lachman’s, varus/valgus
7- Gait
Causes of anterior knee pain
- PFP
- Hypertrophic fat pad syndrome
- Patellar instability
- Quadriceps tendonitis
- Patellar tendonitis
- Arthritis
Causes of medial knee pain
- Meniscus tear
- MCL injury
- Pes anserinus bursitis
- medial plica syndrome
- hypertrophic fat pad syndrome
Causes of lateral knee pain
- Meniscus tear
- Biceps tendonitis
- hypertrophic fat pad syndrome
- ITB syndrome
Causes of diffuse knee pain
- Osteoarthritis
- Inflammatory arthritis
- Septic arthritis
- trauma –> haemarthrosis
- PVNS
- neoplastic
which meniscal tear is more common
medial (lateral more common in ACL tear)
common meniscal tear in older patients
degenerative- posterior horn of medial meniscus
describe the meniscal zones and their management
Red zone (outer third, vascularized therefore try to repair as increased chance of healing)
Red white (middle third)
White zone (inner third, avascular – will not heal, need debridement)
Sx meniscus tear
- pain (joint line tenderness)- can be intermittent
- locking/clicking (mech Sx)
- delayed or intermittent swelling/effusion
Indications for non-operative Mx meniscal tear
- <5mm stable peripheral tear
- Stable vertical longitudinal tears (peripheral)
- Infrequent and minimal mechanical Sx
- Associated ligamentous instabilities
- Medically unfit
O/E meniscus tear
joint line tenderness, effusion, McMurray’s
Ix for meniscal tears + what you would see
- Radiographs, MRI
- Double PCL sign = bucket handle tear (vertical tear which may displace into the notch), fluid where meniscus should be
Mx meniscal tears
Operative = partial meniscectomy or arthroscopic meniscal repair (FasT-Fix)
Non-operative = if <5mm, in red (peripheral) zone, no Sx, unfit
What is the common Hx/Sx of an articular cartilage lesion?
- usually follows trauma
- joint line tenderness/localised pain
- catching sensation
- incidental/accompanies another injury
- effusion
partial vs full thickness chondral lesions
partial = avascular full = potential to fill with fibrocartilage (type 1 collagen)
problem with articular cartilage defects?
gives rise to loose bodies, painful and accelerates OA
Grading of cartilage defects
Imaging for articular cartilage tears
- x-ray
- CT- tibial tubercle to trochlear groove distance, Q angle
- MRI with gadolinium
Surgical Tx for AC lesions- indications/contraindications
- Surgery grade 3/4 lesions
- Avoid in: obesity, inflammatory, degeneration
What is OAT?
OAT replaces chondral defects with normal hyaline articular cartilage, a distinct advantage over microfracture.
A plug of the patient’s own healthy cartilage and bone is harvested from a non-weight bearing portion of the joint.
One or multiple strategically arranged plugs can be transferred to fill the defect.
Surgical Tx of chondral lesions
- microfracture
- OATS
- ACI and osteochondral allografft
The last 2 work best
What is ACI?
Autologous chondrocyte implantation (ACI)
Effective for treating small areas of cartilage damage
Describe the proces of microfracture for chondral lesions
Multiple small holes in the surface of the joint, which stimulates a healing response
Microfracture for AC lesions- benefits
- immediate post-op ROM on passive movement
- Weight bearing 6-8 weeks
- RTP after 4-9 months
OATS- recovery period
NWBing 3 weeks
immediate full ROM
4 months return to sport
ACI- recovery period
- Immediate CP
- NWBing till ROM/quads strength fully restored
- FWB 10-12 weeks
- offloading brace may be used
- 12-18 months before high impact
Classic Hx ACL tear
- ‘pop’, collapse
- immediate swelling
- couldn’t continue to WB
- Lack of confidence
- episodes of giving way
ACL tear O/E
- positive anterior drawer
- positive Lachman’s
- effusion
- quadricep avoidance gait (don’t fully extend knee)
O/E, what severity ACL tear requires surgery
Grade II/III pivot shift
classic injury that causes and ACL tear
non-contact pivoting
Epidemiology of ACL tears
F5>M1 – landing biomechanics and NM activation patterns (quad dominant)
Ix ACL tear
radiograph
MRI
Preferred Mx ACL injury for jumpers vs footballers and the negatives of both
JUMPING ATHLETES
- hamstring graft
- RTP delayed 6 months
FOOTBALLERS
- bone patellar tendon bone (BTB) autograft
- bone-on-bone healing
- reduced laxity in graft
- 30% incidence anterior knee pain
Post-op ACL
- early ROM emphasized
- extension + flexion
- Closed chain exercises emphasised early
- running 3-4 months
- RTP 6-9 months
Causes of PCL injuries
Dashboard injury
Hyperflexion of the knee with plantar-flexed foot
Sx PCL injury
Posterior knee pain but often subtle Swelling. Stiffness. Difficulty bearing weight. Knee instability.
O/E for PCL injury
- positive posterior drawer
- posterior sag
- quadriceps active test
- positive dial at 90deg +/- 30
Mx isolated PCL tears
Brace for 4 weeks & rehab
No surgery
RTP 4-6 months when quads strength equal both sides
Mx combined PCL and MCL/ACL/knee dislocation
Surgical reconstruction < 2 weeks
non- operative Tx PCL injury first 6/52 Rehab
- PWB
- Hamstring/gastroc stretching
- quad strengthening
- Use of PCL that provides dynamic anterior drawer
non- operative Tx PCL injury first 6-12/52
- Increasing quad/gastroc strength + ROM
non- operative Tx PCL injury 13-18/52
- Running and sport-specific exercise
- RTP 4-6 month when quad strength equal
post-op management ACL injury
2-3/52- Brace locked in full extension, passive ROM on2-3, quads isometric
6/52- WB as tolerated, quads isometric, closed chain, open kinetic chain extension (60-0)
> 6/52- WB as tolerated, 0-125 ROM, isotonic quads, leg press, rowing
Functional activity phase 6-9/12
MCL injuries grade 1+2 rehab
- grade 1+2 = hinged brace, NSAIDs
- closed chain exercises
- jogging once quad strength 80% contralateral
- RTP once 80% max speed achieved
Grade 1 & 2 will heal – good blood supply (sup medial & inf medial geniculate arteries)
Grde 1 vs grade 2/3 MCL injury RTP time
grade 1: 10-14 days
grade 2/3: 3-4 months
grade 3- operative – repair or reconstruction
Grade 3 MCL Mx/rehab
- 80% are combined injuries
- Tibial sided tears require acute surgical repairs
- PWB 4-6 weeks
- Closed chain 6 weeks
Squatting, jogging, light agility, slow RTP
MCL Sx
- mostly combo with ACL
- pop
- pain medially
- bruising and effusion
Sx of LCL injuries
- instability near full extension
- Difficulty pivoting/climbing stairs
- Lateral joint line pain and swelling
- often with PCL/ACL
may be accompanies with common peroneal nerve injury
LCL Mx/rehab
Patellar tendonitis- who is affected
- jumping athletes
- repetitive, forceful eccentric contraction of extensor mechanism
Sx patellar tendinitis
insidious onset of anterior knee pain at inferior border of patella – pain after or during activity
O/E patellar tendinitis
- Swelling over tendon
- tenderness inf border of patella
- Basset’s sign (tenderness to palpation at distal pole of patella in full extension but none in full flexion)
Ix for patellar tendonitis- what would you see?
X-ray
- enthesophyte in chronic cases
USS
- thickening of tendon
- hypoechoic areas
MRI
- tendon thickening
- increased signal
- loss of posterior border of fat pad
Mx of patellar tendinitis
- Eccentric exercise programme and stretching of quadriceps and hamstrings
- US therapy
- Chopat’s strap or taping
- NO cortisone injections ⇒ risk of rupture
Indications non-operative knee dislocation Mx
- first time
- no fracture/habitual dislocator
Indications operative knee dislocation Mx
- displaced osteochondral fragments/loose bodies
- MPFL repair
- recurrent instability
- malalignment (osteotomy)
Non-operative Mx knee dislocation
- 6/52 controlled motion
- closed chain, short arc, quads strengthening
- core/hip strengthening
- j-brace
Method of narrowing TG and TT distance (reducing chance of knee displacement)
Tibial tubercle osteotomy
Most common knee ligament injury
MCL – excessive valgus stress e.g. skiing, rugby, football
MCL Mx
Posterolateral corner injury
LCL, popliteus tendon, popliteofibular ligament
