The Knee Flashcards
Describe MCL prognosis and treatment
- The MCL has a good supply and can heal
- Main considerations are to avoid further injury, increase muscle strength and joint movement
- Provide adequate stress to the healing ligament
- In higher grade or combined injuries braces may be used
Describe MOI of LCL injury and special considerations
- Varus force/ external rotational force
- Hyperextension/ varus force
- Infrequent - 1.1 % of athletic knee injuries (Majewski et al, 2006)
- Other structures in the same area may also be injured (posterolateral complex)
- Common peroneal nerve injured in conjunction in 15% of cases
- Peroneal nerve assessment = Sensation in first webspace + Ankle dorsiflexion
What are the special tests for the knee?
Effusion testing - Patellar Tap and Sweep sign
Ligaments:
ACL - Anterior Draw/ Lachman’s (30o)
PCL - Posterior sag sign/ Posterior Draw
MCL - Valgus Stress Test (0 and 30o)
LCL - Varus Stress Test (0 and 30o)
Meniscus:
- Joint line tenderness
- McMurrays (consider if appropriate may cause further injury)
- Thessaly (twist at 5 and 20o)
Patellar Instability - Apprehension test
Describe LCL prognosis and treatment
- Low grade injuries may heal
- Bracing may be used to help
- Grade 3 injuries (ruptures) may require surgery
What are the major ligaments of the knee?
ACL - Anterior Cruciate Ligament
PCL - Posterior Cruciate Ligament
LCL - Lateral Collateral Ligament (or fibular)
MCL - Medial Collateral Ligament (or tibial)
Describe MOI of PCL injury
- Posterior force onto the tibia (eg RTA dashboard injury or fall onto flexed knee)
- Direct contact onto tibia with foot fixed leg in rugby
- Hyperextension injury
rare in sport
What is the prognosis and treatment for ACL injury?
- The ACL does not heal spontaneously
- Surgery considered when desire to return to sports involving pivoting/jumping/change of direction or giving way on daily functional activity
- Rehabilitation is extensive whether or not surgery is performed (lasts 9-12 months)
Describe PCL prognosis and Treatment
- PCL injuries may heal if lower grade
* Bracing can be used to assist healing by putting pressure on the posterior tibia
Name the knee flexor muscles and their attachments
Bicep Femoris
(O) The long head of biceps femoris arises from the ischial tuberosity.
(O) The short head arises from the lateral lip of the linea aspera and lateral supracondylar line of femur.
(I) head of fibula.
Semitendinosus
(O) ischial tuberosity
(I) pes anserinus (proximal end of tibia below medial condyle)
Semimembranosus
(O) ischial tuberosity
(I) medial condyle of tibia
Sartorius (weak flexor)
(O) Anterior Superior Iliac Spine (ASIS)
(I) Pes Anserinus
Gracilis (weak flexor)
(O) Pubic ramus/ ischial ramus
(I) Pes Anserinus
Summarise ligament injuries (prognosis/treatment/rehab goals)
- Ligament injuries occur with trauma!
- The injured structures depends upon the mechanism of injury
- The MCL has the capacity to heal
- General principles of treatment include restoration of ROM, reduce swelling and muscle strengthening
- Bracing may be used to assist healing
- Surgery is required where multiple ligaments are injured or in some cases of higher grade injury
What is the MOI of Meniscus injury?
- Sudden acceleration/ deceleration
- Twisting on the knee especially when weight bearing
- May be very trivial injury if degenerative tear
- Older patients more likely to have degenerative tears
Name the knee extensor muscles and their attachments
Rectus Femoris
(O) Anterior inferior iliac spine (AIIS), supraacetabular groove
(I) Tibial tuberosity (via patellar ligament), patella
Vastus Lateralis
(O) Intertrochanteric line, greater trochanter, gluteal tuberosity, linea aspera of femur
(I) Tibial tuberosity (via patellar ligament), patella, (lateral condyle of tibia)
Vastus Medialis
(O) Intertrochanteric line, pectineal line of femur, linea aspera, medial supracondylar line of femur
(I) Tibial tuberosity (via patellar ligament), patella, (medial condyle of tibia)
Vastus Intermedius
(O) Anterior surface of femoral shaft
(I) Tibial tuberosity (via patellar ligament), patella
assisted by tensor fasciae latae
(O) outer lip of anterior iliac crest, Anterior superior iliac spine (ASIS)
(I) Iliotibial tract/ band
What are the subjective signs of meniscus injury?
MOI Clicking Catching Locking Swelling (delayed)
What are subjective clues for ACL injury?
Swelling immediately following injury- 70% of haemarthroses in the knee result from ACL injury
Giving way on twisting/ turning activities
Diffuse pain within the joint- not easily localised
ACL injury should be suspected in cases where a block to knee extension exists
95.8% of injuries exhibited at least 2 of 4 ‘LIMP’ index features (Ayre et al, 2017) Leg give way Inability to continue activity Marked effusion Pop (heard or felt)
What are the contraindications/cautions of meniscus testing?
- Acutely locked knee
- Associated fracture
- Unstable knee
- Active inflammatory arthritis
Cautions–Osteoarthritis
What blood vessels supply the knee?
Femoral artery
Popliteal artery and vein
Saphenous vein
List the meniscus tests and considerations for use
- Forced block to flexion or extension may indicate a meniscal tear
- Joint line palpation
- McMurray’s test- care required when testing
- Thessaly test (weight bearing rotation)
•Tests for meniscal pathology are not very accurate and have potential to cause futher injury
What are the key subjective clues to look for in knee assessment?
Traumatic MOI? Pop heard/felt? Rapid onset of swelling? Weight bearing ability Locking Giving way
Describe meniscus injury treatment strategies
- Conservative–Reduce swelling and pain–Restore ROM –Restore muscle strength
- Surgical–Menisectomy/ partial menisectomy–Repair (preferred if possible)
What bones does the knee consist of?
Tibia
Fibula
Femur
Patella
Describe quadricep/patellar tendon pathology
- In young patient’s (early teenage years most common) consider traction apophysitis
- Osgood-Schlatters/ Sinding-Larsen-Johannson
- Specific tenderness with palpation of inferior aspect of patella/ tibial tuberosity
- Characterised by localised inflammation
- Tendinopathy typical in patients aged 15+
Treatment
Decrease load–Restore strength and progressively increase load
Describe MOI of MCL injury
- Sufficient valgus force to the knee
- Blow to the lateral aspect of the leg whilst the foot is fixed
- Indirect- twisting injury when foot caught (eg studs in turf)
•Total ruptures rarely occur without some degree of associated injury (often ACL)/ meniscal injury
Describe MOI for Quadricep/patella tendinopathy
- Diagnosis based on history, palpation and pain on specific use of involved tendon
- Often overuse (excessive running/ jumping/ overtraining etc.)
- Consider biomechanical factors
What nerves supply the knee?
Femoral via Saphenous (central anterior)
Tibial (central posterior)
Common fibular/peroneal (lateral)
Posterior Obturator
What tests can be used to diagnose Quad/Patella tendon rupture?
Active straight leg raise
palpate/visual assessment - gap in tendon/ patellar migration (superior if PT/ inferior if QT)
X ray/USS/MRI imaging
What movements occur at the knee?
Hinge joint = flexion and extension
limited medial rotation in flexion
lateral rotation when ‘unlocking’
What is Infrapatella fat pad/ Hoffa’s syndrome?
Swelling/Pain/Inflammation of fat pad (anterior - below patella)
- May result from injury or insidious
- Repeated microtrauma (e.g kneeling occupations)
- Pain towards full extension/ hyperextension
- Highly innervated = pain
Treatment
Rest/Ice/ Anti inflammatories
What are the subjective clues for MCL injury?
Localised pain
Medial knee effusion
mechanism of injury
Decribe the MOI and signs of Pes Anserinus injury
Often overuse (rarely traumatic) although direct blow also possible
Pain in/close to attachment and on use of sartorius, gracilis, semitendinosis
Tender on palpation
What structures should we be able to palpate during knee assessment?
Medial/lateral joint lines Patella tendon/ligament Infrapatellar fat pad Patella margins (med/lat/inf/sup) Fibular head Gerdy's tubercle Pes anserinus Hamstring tendons Popliteal fossa Tibial tuberosity Quad tendon IT band Medial/Lateral retinaculum
What is Patellofemoral pain syndrome? Dicsuss impact and diagnosis
Pain where patella contacts femoral groove
limits activities of daily living that load a flexed knee - stairs, squatting, sitting
Diagnosis largely based on exlcusion of other pathologies
What is the MOI for an ACL injury?
More often non contact valgus collapse
Often in cutting/landing/pivoting
also seen in hyperextension, varus internal rotation
Describe PCL prognosis and Treatment
- PCL injuries may heal if lower grade
* Bracing can be used to assist healing by putting pressure on the posterior tibia
Describe MOI of PCL injury
- Posterior force onto the tibia (eg RTA dashboard injury or fall onto flexed knee)
- Direct contact onto tibia with foot fixed leg in rugby
- Hyperextension injury
rare in sport
