11e. Knee

Question 1

ddx knee pain

Answer 1

general:
- osteoarthritis

Major injury
- patellar dislocation
- patellar fracture
- fracture

Injury:
- Meniscus tears
- Anterior cruciate ligament injury
- Posterior cruciate ligament injury
- medial / lateral collaternal ligament injury
- Bakers cyst

Paeds:
- osgood schallter
- patellofemoral pain syndome (inc chondomalacia patellae)
- osteochondiritis dissicens
- Patellar tendonitis
- Patellar sublaxation

Question 2

what is a sprain

Answer 2

damage to the ligaments of the joint (tear or stretch)

Question 3

valgus vs varus

Answer 3

“Valgus” is the medical term for a force that pushes in toward the center of your body.

“Varus” is the medical term for pushing out, away from the center of your body.

Question 4

presentation osgood schalatter

Answer 4

gradual onset of symptoms:
Visible or palpable hard and tender lump at the tibial tuberosity
Pain in the anterior aspect of the knee
The pain is exacerbated by physical activity, kneeling and on extension of the knee

typically occurs in patients aged 10 – 15 years, and is more common in males. Osgood-Schlatter disease is usually unilateral, but it can be bilateral.

Question 5

Management osgood schlatter

Answer 5

Reduction in physical activity
Ice
NSAIDS (ibuprofen) for symptomatic relief
Once symptoms settle, stretching and physiotherapy can be used to strengthen the joint and improve function.

Question 6

what is osgood schlatter - pathophysiology

Answer 6

Inflammation on the tibial epiphyseal plate.

There are multiple small avulsion fractures, where the patella ligament pulls away tiny pieces of the bone.

This leads to growth of the tibial tuberosity, causing a visible lump below the knee. Initially this bump is tender due to the inflammation, but has the bone heals and the inflammation settles it becomes hard and non-tender.

Question 7

what is patellofemoral pain syndrome

Answer 7

Patellofemoral pain syndrome (PFPS) is a common condition that affects the knee joint. It is characterised by pain around or behind the patella, which worsens with activities such as running, jumping, or squatting

Chondromalacia patellae is damage to the cartilage at the back of the kneecap (patella). The usual treatment advised is to avoid overuse of the knee and to have physiotherapy, which is effective in most cases.

Question 8

management Patellofemoral pain syndrome including Chondromalacia patellae

Answer 8

avoid overuse of the knee
physiotherapy

Question 9

what is osteochondritis dissecans

Answer 9

a small segment of bone begins to separate from its surrounding region due to a lack of blood supply. As a result, the small piece of bone and the cartilage covering it begin to crack and loosen.

–> oedema, free bodies and mechanical dysfunctions.

common at end of femur

It affects children and adolescents with open growth plates (juvenile OCD) and young adults with closed growth plates (adult OCD). OCD may progress to degenerative changes if untreated.

Question 10

features osteochondiritis dissecans

Answer 10

Knee pain and swelling, typically after exercise
Knee catching, locking and/or giving way - more constant and severe symptoms are associated with the presence of loose bodies
Feeling a painful ‘clunk’ when flexing or extending the knee - indicating the involvement of the lateral femoral condyle

Joint effusion
Full range of movement in the joint without signs of ligamentous instability

Question 11

risk factors osteochondiritis dissecans

Answer 11

Trauma
Male
Genetic

Question 12

invetsigations ?osteochondiritis dissecans

Answer 12

X-ray (anteroposterior, lateral and tunnel views) - may show the subchondral crescent sign or loose bodies

MRI - used to evaluate cartilage, visualise loose bodies, stage and assess the stability of the lesion

CT - may be used in preoperative planning and in cases where MRI is not available or contraindicated

Question 13

complications osteochondiritis dissecans

Answer 13

OCD can result in pain, functional impairment, knee joint effusions, loose body formation and osteoarthritis.

Question 14

management osteochondiritis dissecans

Answer 14

guided by orthopaedic input - may be conseravtive, may be surgical

Surgical approaches include:
Arthroscopic subchondral drilling to promote revascularisation.
Arthroscopic debridement and fragment stabilisation.
Arthroscopic excision, curettage and drilling.
Open removal of loose bodies, reconstruction of the crater base and potential replacement with fixation.
Bone grafting and autologous chondrocyte transplantation

Question 15

what is patellar sublaxation

Answer 15

partial dislocation

Medial knee pain due to lateral subluxation of the patella
Knee may give way

Question 16

what is patellar tendonitis

Answer 16

More common in athletic teenage boys
Chronic anterior knee pain that worsens after running
Tender below the patella on examination

“Jumpers knee” caused by small tears in the patellar tendon that mainly occurs in sports requiring strenuous jumping and results in localized patellar tendon tenderness.

Question 17

what is a meniscal tear?

Answer 17

damage to the meniscus, which is cartilage in the knee joint.

It is sometimes described to patients as damage to the cartilage.

Question 18

Presentation meniscal tears?

Answer 18

PC: twisting injury eg sports, “pop” sound, pain, stiffness, swelling, restricted range of motion, instability, knee giving way, referred pain

o/e: localised tenderness, swelling, restricted ROM, positive mcmurrays test

Question 19

plan ?meniscal tear

Answer 19

Investigation
1. MRI scan is usually the first-line imaging investigation for establishing the diagnosis.
2. Arthroscopy can be used to visualise the meniscus within the joint and is the gold-standard investigation for diagnosing a meniscal tear. Arthroscopy can also be used to repair or remove damaged sections of the meniscus.

Management
Conservative management (RICE)
NSAIDs for analgesia
Physio for rehab after swelling reduced
Surgery - arthroscopy - repair/resection (often results in osteoarthritis)

Question 20

gold-standard investigation for diagnosing a meniscal tear

Answer 20

Arthroscopy can be used to visualise the meniscus within the joint and is the gold-standard investigation for diagnosing a meniscal tear. Arthroscopy can also be used to repair or remove damaged sections of the meniscus.

Question 21

what do the ACL and PCL do?

Answer 21

The ACL stops the tibia from sliding forward in relation to the femur.

The PCL tops the tibia sliding backwards in relation to the femur.

Question 22

presentation ACL tear

Answer 22

PC: twisting injury to knee, pain, swelling, “pop” sound, knee may buckle due to instability

o/e: instability of knee joint whereby the tibia can move anteriorly below the femur therefore anterior drawer test / lachmanns

Question 23

investigation ACL tear

Answer 23

MRI scan is usually the first-line imaging investigation for establishing the diagnosis.

Arthroscopy can be used to visualise the cruciate ligament and is the gold-standard investigation for diagnosing a cruciate ligament tear.

Question 24

gold-standard investigation for ACL tear

Answer 24

Arthroscopy

Question 25

management ACL tear

Answer 25

1. NSAIDs are usually used first-line for analgesia in MSK injuries.
2. Crutches and knee braces may be required to help protect the knee while mobilising.
3. Physiotherapy can be used before and after surgery for rehabilitation.
4. Arthroscopic surgery to reconstruct the ligament is often required, particularly in active and young patients. The type and timing of surgery will be based on individual factors, such as the extent of the ACL injury and the patient’s activities (e.g., are they a young competitive athlete or a sedentary older patient). A new ligament is formed using a graft of tendon from another location. Options for graft tendons used to reconstruct the ACL include:
   Hamstring tendon
   Quadriceps tendon
   Bone-patellar tendon-bone (taking part of the patella tendon as well as the bone it inserts into)

Question 26

Presentation PCL injury

Answer 26

PC: traumatic knee effusion and increased laxity on a posterior drawer test

MoI: force onto a bent knee wither by falling or when the shin hits the dashboard in RTC

o/e: effusion, posterior sag test positive

Question 27

MoI ACL

Answer 27

non-contact
twisting movement with foot on the ground
may feel a pop
unable to play on

Question 28

MoI PCL tear

Answer 28

force onto a bent knee wither by falling or when the shin hits the dashboard in RTC

Question 29

MoI collateral ligament tear

Answer 29

contact sporting injury
blow onto side of the knee

or MCL can be skiing

Question 30

MoI meniscus tear

Answer 30

weight bearing twisting injury
knee locking

Question 31

what kind of exerted stress causes Medial collateral ligament injury

Answer 31

Medial collateral ligament injury occurs when excessive valgus stresses or external rotation forces are placed on the knee joint.

Question 32

what kind of exerted stress causes lateral collateral ligament injury

Answer 32

lateral collateral ligament injury occurs when excessive varus stresses or external rotation forces are placed on the knee joint.

Question 33

presentation medial collateral ligament damage

Answer 33

PC: medial-sided knee pain above or below the joint line. Patients are usually able to walk.

Question 34

Management medial collateral ligament damage

Answer 34

The management of an MCL injury is dependent on the grade of injury:
Grade I Injury: Rest, Ice, Compression, and Elevation (RICE) with analgesia (typically NSAIDs) as the mainstay. Strength training as tolerated should be incorporated, with an aim to return to full exercise within around 6 weeks.

Grade II Injury: Analgesia with a knee brace and weight-bearing/strength training as tolerated. Patients should aim to be able to return to full exercise within around 10 weeks

Grade III Injury: Analgesia with a knee brace and crutches, however any associated distal avulsion then surgery is considered. Patients should aim to be able to return to full exercise within around 12 weeks.

Question 35

if there is a contact trauma, what do you always need to investigate knee pain

Answer 35

Any patient following trauma with significant knee pain and swelling should have a plain film radiograph to exclude any fracture.

Question 36

what are bakers cysts

Answer 36

A Baker’s cyst is a fluid-filled sac in the popliteal fossa, causing a lump.
Synovial fluid is squeezed out of the knee joint and collects in the popliteal fossa. A connection between the synovial fluid in the joint and the Baker’s cyst can remain, allowing the cyst to continue enlarging as more fluid collects there.
Baker’s cysts are contained within the soft tissues. They do not have their own epithelial lining.

Question 37

if you see a bakers cyst, what else should you suspect

Answer 37

In adults, Baker’s cysts are usually secondary to degenerative changes in the knee joint. They can be associated with:
Meniscal tears (an important underlying cause)
Osteoarthritis
Knee injuries
Inflammatory arthritis (e.g., rheumatoid arthritis)

Question 38

Presentation bakers cyst

Answer 38

PC: symptoms localised to popliteal fossa- pain or discomfort, fullness, pressure, palpable lump or swelling, restricted ROM

o/e: the lump will be most apparent when the patient stands with their knees fully extended. The lump will get smaller or disappear when the knee is flexed to 45 degrees (Foucher’s sign).
Oedema may occur if the cyst compresses the venous drainage of the leg

Question 39

ddx lump in popliteal fossa

Answer 39

bakers cyst
Deep vein thrombosis
Abscess
Popliteal artery aneurysm
Ganglion cyst
Lipoma
Varicose veins
Tumour

Question 40

plan ?bakers cyst

Answer 40

Investigations
Ultrasound is usually the first-line investigation to confirm the diagnosis. It is also used to rule out a DVT.
MRI can evaluate the cyst further if required, for example, before surgery. They can also demonstrate underlying knee pathology, such as meniscal tears.

Management
No treatment is required for asymptomatic Baker’s cysts.
Non-surgical management for symptomatic Baker’s cysts include:
Modified activity to avoid exacerbating symptoms
Analgesia (e.g., NSAIDs)
Physiotherapy
Ultrasound-guided aspiration
Steroid injections

Surgical management typically involves arthroscopic procedures to treat underlying knee pathology contributing to the cyst, such as degenerative changes or meniscal tears. Resection of the cyst is difficult, and the cyst is likely to recur, particularly when another knee pathology is present.

Question 41

most common cause of lateral knee pain in athletes

Answer 41

Iliotibial band syndrome is the most common cause of lateral knee pain in athletes, with a reported incidence of 1.6-12%. The exact pathology of ITBS is unknown*, however is thought to be linked to repetitive flexion and extension of the knee, causing impingement of the band against the lateral femoral condyle.

Question 42

management ITB syndrome

Answer 42

In the acute phase, treatment includes activity modification, ice, and non-steroidal anti-inflammatory drugs. Offer a combined local anaesthetic and corticosteroid injection if severe pain or swelling.

During the sub-acute phase, emphasis is on stretching of the iliotibial band and soft-tissue therapy for any myofascial restrictions.

The recovery phase focuses on a series of exercises to improve hip abductor strength and integrated movement patterns. The final return to running phase is begun with an every-other-day programme, starting with easy sprints and avoidance of hill training with a gradual increase in frequency and intensity.

Consider surgery if refractory to conservative treatment.

Question 43

special tests for ITB syndrome

Answer 43

Nobles test – the patient lies in a supine position and the examiner places a finger on the lateral femoral condyle, with the knee slowly extends. A positive test is indicated when pain is felt at 30 degrees, when the ITB passes over the lateral femoral condyle.

Renne test – the examiner stands in front of the affected knee and puts pressure on the lateral epicondyle, with the patient then asked to squat. A positive test is indicated by the presence of pain at 30 degrees of flexion.