Lecture 2 - The Knee Flashcards
What are the two articulations in the knee joint?
Patello-femoral joint - articulation between the posterior surface of the patella (sesamoid bone) and the trochlear surface of the femur
Tibiofemoral joint - articulation between the condyles of the femur and the tibial plateau forming a modified synovial hinge joint
List the intra-articular components of the knee (excluding bones) and identify which are extra-synovial
PCL
ACL - extra-synovial
Menisci
Fat pads - extra-synovial
Suprapatellar bursa
Identify 5 reasons why glutes are important to knee pathology
- Reduce iliotibial band loading and irritation which causes lateral knee pain, this is because if the glutes are weak, smaller muscles which attach into ITB overwork and this leads to inflammation and irritation over the tibial tubercle
- Reduces force on knee joint
- Stabilises pelvis to maintain proper leg and knee alignment
- Stability in the hip prevents femoral medial rotation which would cause lateral tracking of kneecap
- Prevents knee from entering too much of a valgus position when squatting, running or landing from a jump
What are the three muscles that insert into the pes anserine?
Gracilis
Semitendinosus
Sartorious
Describe the general properties of a synovial effusion in the knee
Onsets over 3-6 hours
Slight to moderate tension
Smaller volume therefore often missed
Occurs in slight to moderate injuries
Describe the general properties for a haemarthrosis
Onset is immediate
High tension
Large in volume and obvious
Occurs in significant and severe injuries
What is the milk test and explain as you go along?
Milk test - finger and thumb on distal hand come up onto joint line and gently milk the suprapatella bursa
The suprapatella bursa is intra-capsular and therefore swelling in the knee joint moves into the bursa
If the finger and thumb separate on the distal hand this indicates an effusion as the swelling separates your fingers
What is the patella tap test
Pressure on proximal side of the knee squeezes fluid under the patella
Tap patella down, if it drops and clicks onto the femur this is positive as it indicates that the patella is moving through the fluid to hit the femur, if it doesn’t move that’s because the patellar was already on the femur and therefore swelling isn’t indicated
How can you treat a knee effusion
Medication (refer to GP)
Gentle closed chain exercises that mobilise the knee i.e. cycling
RICE
Potential aspiration if severe
How do you clear the hip and why should you do so (name specific conditions)
You should clear the hip to eliminate hip conditions that refer pain to the knee. This includes conditions such as osteoarthritis, ITB syndrome, nerve compression, tight hip muscles and tendonitis
- AROM at the hip - Hip pathology indicated depends on results i.e. tight hip flexors can impact knee
- PROM at the hip - look for capsular pattern, if articular capsule of hip is indicated there will be limited internal rotation, flexion and abduction
Why do tight hip flexors cause knee pains?
Tight hip flexors pull the pelvic bone into anterior tilt reducing movement of the femur
The reduced movement of the femur leads to internal rotation at the knees, this causes tendons, ligaments and muscles to tighten to protect the knee leading to pain and increase likelihood of injury
What specific movement indicates an arthritic knee?
Lack of passive hyper extension following passive flexion and extension
What is the first thing you would do if you suspected an ACL or PCL injury and why?
These are intracapsular ligaments and therefore injury can cause an effusion so during assessment, effusion testing must be performed
What might you feel on palpation of someone with an affected ACL? Is it a relevant or effective palpation?
Tenderness, however it is not a consistent or effective marker for picking up ACL injuries
How do you perform the anterior draw test for an ACL injury and what should you do first?
First - test the integrity of the PCL using the posterior drawer test as laxity picked up in the ACL test could actually be due to initial sagging of the tibia due to an injured PCL
- Flex patient’s knee to 90 degrees and sit on their foot
- Place hands round the proximal portion of the leg with thumbs in the joint line
- Draw the tibia forward
Positive = marked laxity and/or pain compared to the other side
Why is the anterior drawer test not effective in a lot of ACL tears?
The anterior drawer test only tests the antero-medial band of the ACL therefore only picking up 15-20% of all ACL tears as the majority of the ligament is made up of the postero-lateral band.
So a complete tear will be picked up but incomplete tears will not
How would you perform a modified anterior drawer test to test for an MCL rupture alongside an ACL rupture?
- Externally rotate the knee to tighten the medial ligament
- If the anterior drawer was previously lax, this should be eradicated when the test is repeated in this position
- If it is not eradicated, this could indicate an issue with the MCL no longer acting as a secondary restraint
How do you perform the Lachmann’s test and what do you have to do first?
Test the PCL first - posterior sagging of the tibia can lead to a false positive in ACL tests
- Have the patient in supine and have your knee or a towel under the patient’s knee to bring it to 20-30 degrees flexion
- Place your proximal hand on the distal femur and your distal hand behind the proximal tibia with fingers in the joint line
- Have your thumb on the tibial tuberosity and then perform an anterior draw
- A positive is if there is a squishy end feel and/or laxity
How do you perform the pivot shift test and what does it do?
Patient in supine
Bring knee into full extension, apply internal rotation at the foot and apply a valgus force at the knee (if ACL is torn the tibia will sublux forward on the femur)
Gently flex to around 30 degrees
Positive = hearing or feeling a clunk which is the lateral tibial plateau reducing
How would you treat an ACL tear in the acute phase?
Treat effusion and/or haemarthrosis if relevant
NSAIDs and painkillers
RICE
Refer for an MRI which is the gold standard imaging for a suspected ACL tear
Refer for an x-ray to eliminate a fracture
Arthroscopy is an alternative to an MRI but is more invasive and expensive (however arthroscopy can be used for treatment as well and sometimes MRIs don’t pick up on partial or chronic tears)
What does the ACL do?
Prevents anterior tibial translation on the femur
What are the common movement causes of an ACL tear?
Pivoting with your foot firmly planted
Experiencing a strong valgus force i.e. during a football tackle from the lateral side
Overextension of the knee due to a sudden directional or speed change
What symptoms will patients with an ACL tear likely report
Experiencing a sudden and severely painful ‘pop’ in the knee during injury
Giving way during twisting or rising
Persistent deep aching pain
What are some methods of treatment for non-acute ACL injuries
Surgery followed by post-surgical rehab
Non-surgical rehab
Local measures to decrease inflammation i.e. NSAIDs
Splinting/taping - minimal evidence to indicate it’s effectiveness in improving long term patient outcomes but can reduce rate of subsequent re-injury due to sensory feedback from the splinting
What are key aims during the 1st week of post-surgery for an ACL tear?
Reduce swelling
Walk without crutches
Prevent deep vein thrombosis through foot and ankle exercises
Mobilise kneecap
Isometric contraction of quads and hamstrings with knee bent over a pillow/towel (no open chain quad movements)
What are key aims during weeks 2-6 of post-surgery for an ACL tear?
Increasing knee flexion range to 130
Mobilising scar by mobilising the kneecap
Proprioception work
Strengthening of quads and hamstrings (no open chain quad movements, don’t do resisted hamstring work if a hamstring graft has been used)
What are key aims during weeks 6-12 of post-surgery for an ACL tear?
Achieve full range of movement in the knee
Progress strengthening quads and hamstrings (no open chain quad movements)
Avoid varus and valgus strains
Propioception work
General fitness
What are key aims during week 12 - 5 months of post-surgery for an ACL tear?
Introduce open-chain quad exercises
Work on strength and confidence by incorporating non-contact sport specific exercises
Increased proprioception and balance exercises
What are key aims from 5 months onward of post-surgery for an ACL tear and what are the conditions for returning to sport
Perform sport-specific exercises
Begin a return to sport after the following conditions are met:
Laxity in ligaments
Fully cardiovascularly fit
No swelling
Full strength in quads, hamstrings and calves Equal balance between the two legs
What occurs between 0-2 weeks on a non-surgical rehab pathway for an acl tear?
- Aiming to restore full extension and re-gain quad control gradually working on flexion
- Knee should be kept straight and elevated when sitting or laying and locked into extension in a brace when standing and walking (crutches should be used)
- Brace is unlocked and removed at advice of the doctor and occurs 6 weeks or later when adequate quad control is achieved
- Pain or activities that result in locking or giving way should be avoided
- RICE, ankle pumps and patellar mobilisations
- Seated assisted knee flexions
- Gastroc and soleus stretches, hamstring stretches in supine
- Calf and quad strengthening (gentle, no open chain, no pain)
What occurs between 2-6 weeks on a non-surgical rehab pathway for an acl tear?
- Improve ROM for flexion
- Stretch muscle groups
- Strengthen of muscle groups
- Proprioception
- Restoring normal gait
- Eliminating instability
What occurs between 6-8 weeks on a non-surgical rehab pathway for an acl tear?
- Progressive strengthening
- Maintain ROM
- Advanced proprioceptive exercise
- Running
- Lateral shuffle and cone drills
What occurs between 8 - 12 weeks and onward on a non-surgical rehab pathway for an acl tear?
- Progressive strengthening
- Safe return to work or sports
- Quadriceps and hamstring strength should be nearly equal
- Patient education re sports bracing, healthy BMI and activity modification
- Stretch regularly
- Control pain and swelling
- Equal balance and single leg hop tests
What symptoms do people with a PCL tear complain of and why do they get pain in any mentioned positions?
Instability
Pain going downstairs
Pain crouching down and removing shoes
Pain = due to tibia posteriorly translating in these positions and therefore being afforded more rotation causing pain
Why does quad weakness increase risk of a PCL injury:
Quads are the first resistance to anterior translation of the femur i.e. when walking down a hill
If quads are weak, more strain is put on the PCL
What movements cause PCL injuries?
When you are going forward and then your foot isn’t:
- Going down a hill and your foot gets stuck
- Direct force to tibia in opposite direction to your forward motion i.e. low rugby tackle
How would you treat a PCL injury in the acute stage?
- RICE
- NSAIDs/pain relief
- Reduce/treat effusion and/or haemarthrosis if applicable
- Surgery for severe tears (arthroscopy)
- Braces and crutches to assist with stability until quadricep strength is regained
- Gold standard imaging = MRI
What occurs in phase 1 (0-4 weeks) of rehab for a PCL injury
- PWB and WBAT on crutches
- Brace overnight fixed in extension to protect the ligament
- Quadricep activation
- Gastroc and hamstring stretching
- Aim to restore some ROM
- Patellar mobilisation
- Hamstring contraction avoided to avoid posterior tibial translation
- Can have NMES if unable to achieve quadricep stimulation
What occurs in phase 2 (4-8 weeks) of rehab for a PCL injury
- Achieve full ROM
- Glutes activated
- Weaned off crutches
- Proprioception and balance progression
- Patellar mobilisations
- Still avoid hamstring contractions
What occurs in phase 3 (8-12 weeks) of rehab for a PCL injury
- Maintain range
- Advanced proprioception and balance
- Strengthening and emphasise use of glutes for hip and pelvis stability
- Progress to a functional return to work/activity
- At end of phase remove brace and begin hamstring contractions between 0-55 degrees progressing from there
How do you perform a posterior drawer test for a PCL tear?
- Patient in supine
- Flex knee to 90 degrees and sit on foot to stabilise femur
- Hold the tibia with thumbs in joint line
- Translate tibia backward
- Positive = marked laxity/lack of end feel
How do you perform reverse lachmann’s test to test for PCL tear
- Patient in supine
- Flex knee 20-30 degrees over your knee or a towel
- Proximal hand stabilises femur, distal hand round back of tibia in joint line
- Thumb on tibial tuberosity
- Draw tibia backward
- Springy end feel/laxity = positive
Why would you palpate from femur onto tibia, what should you feel and what do differing results indicate?
- To test for PCL tear (causing posterior laxity)
- Tibia should be anterior
- If the tibia is anterior but other tests indicate PCL test, indicates grade 1
- If the tibia and femur are in line then this indicates a grade 2 tear
- If you drop backward onto the tibia it indicates a significant tear at grade 3
How do you perform a sag sign test?
- Patient in supine
- Knee in 90 flexion
- Hip in 45 flexion
- Sit on patient’s foot
- Tibia should be 10mm anterior to femur in this position, if it sags backward, this is a positive sag sign and indicates PCL damage
How is a dial test performed and what do the results indicate?
Test:
- Patient in prone
- Bend knee to 30 degrees and externally rotate foot and measure angle
- Repeat at 90 degrees
Results:
- If 10 degrees more external rotation on injured side compared to uninjured side at 30 but not 90, indicates posterolateral complex instability
- If 10 degrees more external rotation on injured side compared to uninjured side at 90 and not 30, a PCL instability is indicated
- If at 90 and 30, PCL injury and PLC instability indicated
What is the posterolateral complex composed of?
LCL
Popliteus tendon
Popliteofibular ligament
What is the clinical presentation of an LCL injury
- Varus force
- Nearly always traumatic and often alongside ACL or PCL injury
- Pain, swelling and tenderness on outside of knee
- Feels like it may give way
What test do you perform to assess for an LCL injury?
Varus stress test:
- Patient in supine
- Knee flexed to 20 degrees over towel or over your knee
- Proximal hand on distal femur with thumb in lateral joint line
- Distal hand holds heel with forearm along medial border of foot and internally rotate tibia
- Apply a varus strain
- Feel for gapping under your thumb, laxity and pain
How would you treat an acute LCL injury?
NSAIDs and pain relief
Refer for an MRI which is the gold-standard for ligament injuries and for an x-ray to rule out fractures
Modify activities that cause pain
If severe, surgery, but uncommon
How do you treat LCL injury in the non-acute stage?
- If activities are causing pain this is a clear indicator that they are stressing the ligament and therefore should be modified during the recovery period
- Restore strength in the quadriceps, glutes, hamstrings (immobilise hamstrings if surgery to protect the reconstruction) and calves, you can utilise isometrics for strengthening
- NWB for first week or if surgery, NWB/PWB with crutches for up to 6 weeks based on ortho advice
- Maximise ROM with pain-free passive exercises
What is the clinical presentation of an MCL injury?
- Can be traumatic due to valgus force
- Can be caused by repetitive valgus strain (skiing, regularly crouching down, breaststroke)
- Tenderness on medial border of knee
- Swelling
- Instability
- Bruising
- Co-occurs commonly with other injuries such as ACL tears and medial meniscal tears
Why does the ACL being injured lead to strain being put on the MCL
MCL is secondary resistance to anterior translation (ACL is primary) so ACL issues can lead to increased strain on the MCL
How do you test for an MCL injury?
Valgus stress test:
- Patient in supine
- Leg flexed to 20 degrees over a towel or your knee
- Proximal hand on distal femur with thumb in medial joint line
- Distal hand under heel with the border of patient’s foot along your forearm and apply external rotation
- Apply a valgus force
- Positive if laxity, pain or gapping under thumb on medial side at joint line
How do you treat an MCL injury?
- NSAIDs and pain relief
- Refer for MRI (gold-standard for ligaments) and for x-ray to check for fractures
- May need crutches and brace as per doctor advice
- Restore ROM
- Strengthening (only to be progressed when current movements are pain free)
- Severe injuries alongside other ligamentous injuries may require surgery
Where are the menisci situated and what is their purpose?
Menisci sit on the tibial plateau supporting and cushioning the condyles of the femur to enable smooth movement of femoral condyles over the tibial plateau
What is true and pseudo locking and true and pseudo giving way?
True locking = knee has to be rotated to unlock
Pseudo-locking = Feeling a hard end feel when ‘lock’ing into extension/hyper-extension
True giving way = falling to the ground
Pseudo giving way = lightly flexing
Identify 6 different types of meniscal tears
Bucket handles
Longitudinal tears
Flap tear
Horizontal tears
Transverse/radial tears
Oblique tears
What is the role of a physio regarding a meniscal tear?
Diagnose, refer and treat symptoms
What is the difference between red and white areas of the menisci regarding healing?
Red areas may heal or can be repaired by surgery (on the outside of the menisci)
White areas won’t heal and either need to be surgically removed or patient has to tolerate problem
What would you expect from palpation for the 2 different sides of meniscal injury
Lateral - tenderness 2cm posteriorly from mid line
Medial - tenderness over mid joint line and 1cm either side
What are the two special tests for the menisci
Thessaly’s - The patient stands on injured leg leaning on shoulder of the practitioner, practitioner stabilises the patient’s hips and then the patient rotates to the left and right. If pain is caused on rotation to the ipsilateral side to the injury, lateral meniscus is indicated and if contralateral side then medial meniscus indicated
Mcmurray’s medial - patient lies in supine, hip and knee flexed to 90, tibia externally rotated, valgus strain applied, knee brought into extension, clunking or symptoms reproduced is positive
Mcmurray’s lateral - patient lies in supine, hip and knee flexed to 90, tibia internally rotated, varus strain applied, knee brought into extension, clunking or symptoms reproduced = positive
How would you treat a meniscal tear excluding rehab
- Refer on for further investigation, they need to have an MRI to see if the tear is in the white or red zone and therefore whether surgery may be indicated and to determine rest of management
- NSAIDs and RICE for acute injury
How would you rehab a torn meniscus?
Weight loss - reduces load going through knee and femur to reduce the rate of erosion of menisci and reduce inflammatory chemicals in the body that can quicken cartilage and meniscal breakdown
Exercises and strengthening - needs to follow orthopaedic decisions made following meniscal rehab surgery
Strengthening: Quads, hamstrings, soleus/gastroc, hip ab and adductors, hip flexors etc to reduce amount of energy/force passed to the meniscus
Flexibility and ROM - Reduces degeneration, keeps joints healthy and creates more movement putting less strain on the knee during twisting and stopping movements
Discuss some of the thoughts and literature around degenerative mensical tears
- No benefit of surgery + physio over just physio in non-arthritic, non-traumatic tears
- General lack of consensus on signs or symptoms of degenerative meniscal tear
- Surgery should only be considered if significant risk to articular processes i.e. repeated effusion, persistent pain and true locking otherwise rehab should always be first attempt/consideration
How would you treat degenerative meniscal tears
Injections
Selective activity
Rehab and conservative management in line with a traumatic meniscal tear
What age are degenerative meniscal tears most common?
Over 45
What is housemaid’s knee and what causes it?
Prepatellar bursitis
Positional overuse trauma from being on all fours
Where is the prepatella bursa?
Sits between the skin and the patella bone
Where is suprapatellar bursa and what does bursitis of this bursa also usually indicate in the knee?
Between the quadriceps and the distal femur, communicates with joint so is usually indicative of swelling in the knee
What is vicar’s knee and what is it caused by?
Superficial infrapatellar bursitis
Kneeling on just your knees rather than all fours
Where is the superficial infrapatella bursa?
Between the patella tendon and skin
Where is the deep infrapatellar bursa and what condition is commonly confused with bursitis of this bursa (and how can you distinguish them)?
Between patella tendon and tibia
Mistaken for patellar tendinopathy
Patellar tendinopathy is felt in the proximal or mid part of patellar tendon
Deep infrapatellar bursa is situated a little lower
Where is the pes anserine bursa?
Deep to the anserine tendons (semitendinosus, gracilis and sartorius)
What is a baker’s cyst?
A defect at the back of the knee capsule
When there is swelling at the knee joint it seeps into a little sac at the back of the joint
Occasionally there is a valve mechanism where it flows into the posterior sac but can’t come out
What is a haem bursitis?
Bleeding into the superficial bursa caused traumatically
What type of bursae (deep or superficial) have greater incidences of infection
Superficial
What is the clinical presentation of most knee bursitis’s
Exquisite tenderness when poked
Gradual, nagging, annoying type of ache
Patient points too a specific area to describe the pain
What objective test would you do if you suspect bursitis?
Diagnosis of bursitis is massively geographic so palpate and feel for exquisite tenderness in a particular place
How do you treat a bursitis/
Ensure no signs of infection
Remove/adjust causative factor
Aspirate if large and uncomfortable
RICE/NSAIDs - Particularly for superficial
Rehab - usually not that relevant as not due to weakness
What positions might put you at more risk of fat pad syndrome
- Standing on one leg i.e. with teenagers, mothers who stand on one side holding their child etc, leaning on one leg forces it into hyper extension
- Genu valgum
- Deep flexion positions i.e. working with plants and children
When might people with fat pad syndrome’s pain be worse and why?
Fat pads are pinched (between femoral condyles and patella) in end range extension so pain is worse going up stairs, standing on one leg or for long periods, cycling with the saddle high so putting the leg forcibly into extension when pushing down on pedal
Fat pads are also pinched in deep flexion so pain is worse in deep squats i.e. when working with children or with plants
What position do people with fat pad syndrome usually rest in?
50 degrees knee flexion as this is the most comfortable position for the fat pads
Where are the infrapatellar fat pads situated?
Below the knee joint, posterior to the patellar tendon
Why do the infrapatellar fat pads have a high potential for pain?
They are very rich in nociceptive nerve endings
Why can infrapatellar fat pad syndrome interfere with mechanics of the joint?
Villi from the fat pad extend into the joint and can interfere with mechanics of the knee joint
What is a potential surgery related cause of infrapatellar fat pad syndrome?
When patients have arthroscopies, the fat pads are the entry site so if people have knee pain post surgery that differs from their original knee pain it is likely because the fat pads have been irritated/injured
What would you expect to see in an objective assessment of someone with fat pad syndrome?
Observation - enlarged fat pads, person stands with hyper-extended knees or one leg
Palpation - enlarged and tender fat pads
Weak eccentric hamstrings: Patient lies in prone and bends to around 10 degrees flexion and then perform resisted extension
Hoffa’s sign: Thumbs on fat pads, 90 degrees hip and knee flexion, hold hands underneath to support the knee, passively bring into full extension, positive sign is pain over the last 20 degrees which is then removed bringing back into flexion
Gentle overpressure into extension causes pain
How would you treat infrapatellar fat pad syndrome?
- Remove/adjust activities that cause the issue
- Strengthen eccentric hamstrings to temper uncontrolled knee extension
- Podiatry referral may be appropriate if there is a biomechanical cause
- Surgery should be an absolute last resort and is often highly unnecessary
What does the timeline look like for muscle strengthening in post ACL surgery rehab
Weeks 0-2: Isometric contractions of quads/hamstrings over a towel, no open-chain quads as this puts too much strain on the ACL
Weeks 2-6: Progress strengthening of quads and hamstrings i.e. sit to stands, but no open-chain quads and no resisted hamstring exercises IF a hamstring graft was used in the surgery
Weeks 6-12: Progress strengthening of quads and hamstrings to include squats, lunges, leg presses etc but still no open chain quad exercises
Weeks 12-5 months: Can incorporate open chain quad exercises and progress strengthening further
5 months onward: Strength should be = in calves, quads and hamstrings between the two legs
What does the timeline look like for range of motion post ACL surgery during rehab
Weeks 0-2: Aim for 90 degrees knee flexion
Weeks 2-6: Aim for 130 degrees knee flexion
Weeks 6-12: Aim for full range of motion
12 weeks onward: maintain full range
What does the timeline look like for reducing symptoms and risks caused by the surgery following ACL surgery
Weeks 0-2: Reduce swelling, come off crutches and prevent deep vein thrombosis by mobilising foot and ankle
Weeks 2-6: Mobilise the scar by mobilising the patella]
Weeks 6-12: When the graft is at its weakest so no twisting or varus and valgus stresses
Week 12-5 months: Strengthen in the varus and valgus directions
5 months onward: Ensure that all necessary conditions are met for a safe return to sport that doesn’t risk the graft tearing. This includes:
- No laxity in ligaments
- Cardiovascularly fit
- Equal strength and balance in both limbs
What does the timeline look like for proprioception post ACL surgery during rehab
0-2 weeks: Not a focus
2-6 weeks: Beginning weight-bearing proprioception work: Single leg stands, wobble boards, bridging on one leg etc
6-12 weeks: Progress proprioception
12 weeks - 5 months: Continue to progress proprioception
5 months onward: Balance and proprioception should be the same on the affected and unaffected leg
What does the timeline look like for general fitness with surgical ACL rehab
0-6 weeks: Not a focus
6-12 weeks: Begin to work on including in the gym and when swimming with straight leg kick
12 weeks - 5 months: Progress cardiovascular fitness toward a return to sport
5 months onward: To return to sport full cardiovascular fitness to be reached
Why does the clunk occur in a positive mcmurray’s and discuss the validity of the test:
The clunk occurs as the torn meniscal fragment is manipulated between the femur and the tibia
The McMurray’s test has been shown to have varying levels of validity, a recent meta-analysis put validity at 70%. This means that it must be combined with other tests to be clinically accurate/relevant.
What is the Ottowa Knee Rule and what are it’s conditions?
The Ottowa knee rule is used to determine whether an x-ray is needed in people over 2 years that have suffered a knee injury to see if it is fractured.
An x-ray referral should be made if any of the following are true:
- Tenderness of the fibula head
- Inability to weight bear both immediately and during the consultation for four steps
- Inability to flex knee to 90 degrees
- Isolated patella tenderness
- Aged 55 years or older
