Disorders of the Knee Flashcards
Anatomy of the knee
A synovial hinge joint - three compartment
Intra-articular cruciate ligaments and extra-articular collateral ligaments + Intra-articular menisci
Function of the Knee
Principally a hinge joint with some limited rotation - minimal inherent bony stability - stability is mainly ligamentous + muscular
Cruciate ligaments
ACL –> anteriomedial tibia to posteriolateral on the femur
PCL –> Posteriolateral tibia to anterimedial on the femur
Resist translational forces of the tibia on the femur and rotational forces
Collateral ligaments
Protect the knee from Valgus or varus forces
The ‘pes anserinus’ inserts into the top of the MCL joining it to the tendons of the sartorius, gracillus and semitendonosis
The LCL is more flexible than MCL so less vulnerable to injury
Knee sprain
Occurs mainly in response to valgus or varus strain
A traumatic effusion of the joint
I - Bruising, II - Partial Rupture, III - Complete Rupture (can be less painful than partial)
O’Donoghue’s triad
A common injury among footballers –>
MCL rupture
ACL rupture
Medial mensical tear
Examination of a Knee sprain
Look –> bruised, swollen and unable to weight bear
Feel –> effusions and local tenderness
Move –> Pain on movement or on stressing the joint/ligament. There may be instability in the joint as well
Investigations for a Knee sprain
X -rays –> will see effusions and increased joint space if the ligaments ruptured
Aspiration –> Clear indicates traumatic synovitis, Blood indicates internal derangement, blood and fat indicates intra-articular fracture
Treatment of an acute knee sprain
Grade I or II treat with rehabilitation and RICE (rest, ice, compression, elevation)
Grade III treat with plaster cast for up to 6 weeks and rehabilitation. In rare cases an operation may be required
Treatment of a chronic knee sprain
Rehabilitation as with acute but may require an operation to fix chronic instability - EUA and arthroscopy with possible ligament advancement with auto- or allo- grafting
Causes of Meniscal Injuries
Acute - twisting or deforming injuries which may cause a ‘snap’ or ‘pop’, may still be able to weight bear but with gradual swelling
Degenerative - from repeated squatting or kneeling leading to pain, discomfort and swelling
Symptoms of chronic Meniscal injures (5)
Patient may report locking, giving way, swelling or clicking
There may be general instability or an ‘unsafe’ sensation
Examination of Meniscal Injuries
Look - Limping/not weight bearing, swollen/Bruised, poss locked
Feel –> Effusions and tenderness (specific or general)
Move –> painful, restricted, may be locked
Special tests –> +ve Mcmurray’s, Squt/ duck walk test, +ve grind test
Investigations in Meniscal injuries
X-rays - effusion and increased joint space if bucket handle tear
MRI - more useful if chronic injury
Aspiration - Blood indicates internal derangement, blood and fat indicates intra-articular fracture
Treatment of meniscal injury
Acute - Rehabilitation (RICE) and arthroscopy for menisectomy/repair
Chronic - physiotherapy/arthroscopy and menisectomy
ACL injuries
Acute - Twisting injury with pop/snap heard and rapid swelling (1-2hrs) + unable to weight bear
Chronic - Knee feels unstable/unsafe and may give way
Examination of acute ACL injuries
Look - limping/not weight bearing, swollen/bruised, poss other injury
Feel - Effusion and tenderness (general or specific)
Move - Painful with RoM limited by pain or effusion, may be unstable
Examination of chronic ACL injuries
Look - Quads wasting (VMO)
Feel - Effusion
Move - Lachman, anterior draw and pivot shift positive
Investigations for ACL injuries
X-rays - effusion, poss avulsion #, joint laxity or subluxation
MRI - only used for chronic injury
Aspirate - Blood indicates internal derangement, blood and fat indicates intra-articular fracture
Treatment for acute ACL injuries
Aspiration or arthroscopy
RICE
Treatment for chronic ACL injuries
Physiotherapy and arthroscopy + reconstruction surgery
Use of prosthetics has fallen into disuse, autografts from hamstring or patellar tendons more common
Who gets Anterior Knee pain?
Young women
Athletes
Middle aged and older women
Greater risk after trauma or dislocation
History in anterior knee pain
Usually retro-patellar pain when squatting, kneeling, going up/down stairs - pain is related to activity
In older patients there is more stiffness on rising which eases with use
Examination in Anterior Knee pain
Look - Wasting
Feel - PFJ irritability and tenderness, may have a positive apprehension test
Move - Retro-patellar creptius and possible tight lateral quadriceps expansion
Investigations in Anterior Knee pain
X-rays - skyline view to assess patella tilt and any maltracking
- Degenerative changes in the PFJ or knee itself
MRI is rarely used but is useful to assess cartilage damage
Treatment in Anterior Knee pain
Physiotherapy and if needed arthroscopy - assess tracking of the patella, Lateral release or assessment/trimming of the articular cartilage
Patella Dislocation
Can be acute or chronic: Recurrent - frequent episodes Habitual - dislocates at will Invariable - always dislocates Constant - never in joint
Investigations in Patella Dislocation
X-rays - AP and Lateral to assess displacement
- skyline to look for tilt, maltracking and dislocation/subluxation
MRI if query cartilage damage
Treatment in Patella Dislocation
Physiotherapy and if needed arthroscopy to assess tracking and perform a lateral release
Can perform a realignment procedure using a tibial tubercle transfer or VMO advancement
History in Patella Dislocation
Acute - nature of injury, severity of pain, Extent of deformity
Chronic - Time since first dislocation, Frequency, nature and cause of dislocation
Examination in Patella Dislocation
Look - Deformity if acute or muscle wasting if chronic
Feel - Positive apprehension test
Move - Tight lateral quadraiceps expansion and retro-patella crepitus
VMO
Vastus medialis oblique - important in maintaining proper patella tracking
History to take when assessing a sports injury
How did it happen? What were the direction and extent of the forces?
Were you able to continue playing? when did symptoms/swelling start?
Is there any: instability (linear or rotatory), swelling, locking, pain,
Extensor mechanism rupture
Occurs when there is a forced flexion of the leg
Osgood-schlatter’s disease (10-15yrs) –> Patella tendon rupture (20-40yrs) –>Patella fracture (40-60yrs) –> Quadriceps tendon rupture (60+yrs)
Pes Anserine Bursitis
Inferiomedial knee pain – generally self limiting with exercise and stretching
More common in older people and women
Sports, diabetes and obesity increase the risk
Patellar tendinitis
A common cause of inferior patella pain in people who repeated jump (sports) and is associated with stiff or injured ankles
Varies from pain only after activity (stage 1) to complete tear (stage 4)
Prepatella burisits
Inflammation of the anterior knee due to inflammation of the bursa due to acute or chronic injury (housemaid’s knee) –> painless but tender significant effusion but no restriction of movement (may be discomfort and crepitus). RICE is usually sufficient to treat but aspiration may be needed if severe
Osteochondritis dissecans
15-20yrs, a small piece of bone breaks from the condyle
This loose body in the joint leads to pain (after exercise), locking, giving way and swelling
Osgood schlatter disease
Occurs in athletics adolescents and presents with pain, swelling and tenderness over the medial tubercle – may swell
Risk factor for tendon rupture but rare
Hypermobility
Common and starts in childhood – family history likely to be positive
Recurrent transient knee pain (can also have back pain)
Will have hyperflexible joints, stretchy skin and easy to test for
Growing pain
Nocturnal pain in children – most commonly leg pain (can be arms) - rubbing and stretching will ease the pain within a few minutes
Chondromalacia patellae
softening of the patella cartilage - commonest in teenage girls. presents as anterior knee pain on using stairs or prolonged sitting. Usually responds to physiotherapy.
Patella subluxation
Medial knee pain due to lateral subluxation of the patella. Knee may also give way.
Patellar tendonitis
More common in athletic teenage boys - chronic anterior knee pain that worsens after running. Will be tender below the patella on examination.
