1. Derbyshire Sports Injuries Clinic presents
The Knee

2. Anatomy- 1st layer

3. The knee joint Made up of two joints: Tibiofemoral joint:
Hinge joint
Collateral ligaments
Cruciate ligaments
Menisci
Patellofemoral joint:
Medial retinaculum
Patellar tendon

4. Anatomy-ligaments ACL PCL MCL LCL Popliteal ligaments
Meniscofemoral ligament
Transverse ligament

5. Anatomy-medial view

6. Anatomy- lateral view

7. Anatomy-posterior view

8. Anatomy- bursae

9. Movements of the knee Flexion Extension
Accessory movements in certain positions can take place with external forces:
Valgus
Varus
External rotation
Internal rotation

10. Patient walks in c/o knee pain
What is the mechanism of injury?
A planted foot with a valgus force and/ or twisting movement is a serious position of danger for the knee
Was there a noise?
Did the knee swell up immediately?
Is there any bruising?
Was the patient able to play on?
Is the patient able to weightbear?
Is there any clicking/ giving way/ locking now?

11. Patient walks in c/o knee pain
Acute, chronic or sub-acute?
Does pain increase or decrease with activity?
Patient’s job and leisure activities and any possible contributing factors?
Gait? Limping or normal walking? Able to cope with stairs?
Does the patient have any hip pain?
Any back pain? Leg pain? Could this be an L3 Nerve root compression?

12. Where is the pain?

13. Causes of haemarthrosis
ACL tear
PCL tear
Patella dislocation
Osteochondral fracture
Peripheral tear of the meniscus (more commonly medial)
Hoffa’s syndrome (acute fat pad impingement)

14. More clinical pearls
There is little effusion with collateral ligament tears
An effusion that develops after a few hours or the next day is a feature of meniscal and chondral injuries
Assume everything with a pop or a snap is an ACL tear
Assume all clicking and locking is meniscal... Especially loss of extension
If the knee locks in extension and flexion is difficult it is likely to be patellofemoral pain
Giving way can be indicative of ACL or meniscal injury, but if this is longstanding with no injury, it may be muscle weakness

15. Ottawa Knee rules Age 55> or <18 Tenderness at head of fibula
Isolated patella tenderness
Inability to flex to 90°
Inability to bear weight both immediately and in the emergency department (4 steps)
High suspicion are:
High speed injuries
Children or adolescents
Clinical suspicion of loose bodies
90% of knee X-rays are normal.

16. Assessment
Observe active range: ability to squat if appropriate, control through the knee.
Observe position of patella in standing
Passive range of movement in supine: loss of particularly extension will cause long term problems
Palpate the patella for differences from side to side

17. ACL assessment Anterior Drawer test: Lachman’s Test
Knee at 90° flexion, foot kept stable
Tibia drawn anteriorly
Assess for degree of movement and end point
Lachman’s Test
Knee at 15° flexion
Draw tibia forward

18. ACL assessment Pivot Shift Test: Loss of ROM, especially extension
Tibia internally rotated
Knee in full extension
Apply a valgus force
In a knee with ACL deficiency the condyles will sublux. The knee is then flexed, looking for the clunk of a reduction, a positive Pivot shift. Extending the knee again, if the knee clicks, this is a positive ‘jerk test’.
Loss of ROM, especially extension
Lateral joint line tenderness due to lateral joint capsule stretching due to subluxation
Medial joint line tenderness if associated meniscal injury

19. ACL injury Relatively common in sport
Over ACL reconstructions performed in the USA every year
Generally sports that involve pivoting... Football, netball, rugby, gymnastics, downhill skiing etc.
2-10 x higher risk in females
Can occur in isolation or with meniscal, articular cartilage and MCL injury

20. ACL injury 75% rupture chance if there was a twist, a pop and a click!
Extremely painful, particularly at first
Athletes are initially unable to continue their activity, and further activity is limited by significant haemarthrosis. Very occasionally this can be delayed.
Some athletes ‘try’ to play again when knee has settled and report incidences of acute instability
Examination of the knee when swollen is very difficult. Diagnosis should be based on subjective report, and appropriate referral made.
MRI is the imaging of choice, but X-ray is needed to check for an avulsion fracture (‘Segond’).
80% of ACL tears have a bone bruise over the lateral femoral condyle.

21. PCL assessment Posterior sag: Reverse Lachman’s Test
Both knees flexed to 90° and patient relaxed
Observe tibia position relative to femur
Reverse Lachman’s Test
Lachman’s prone!
Posterior drawer test
Knee at 90°, push tibia posteriorly
Also assess in internal and external rotation
Assess range and quality of end point
X-ray to ensure no bony avulsion
MRI is the gold standard for PCL tear assessment

22. PCL injury
PCL is a primary restraint to posterior drawer and secondary restraint to external rotation.
Less common than ACL (thicker ligament), usually associated with meniscal and chondral injury as well as lateral meniscus injury.
Usually results from a blow to the anterior tibia with the knee flexed.
Hyperextension may also result in injury to the PCL and posterior capsule.
Pain is poorly defined, posterior pain, sometimes in the calf.

23. Collaterals MCL: Valgus force LCL: Varus force
Test at full extension and also 30° flexion
Grade 1: hurts on testing with no laxity visible
Grade 2: hurts and gaps with laxity but with end point
Grade 3 isn’t that painful on testing, LARGE amount of movement. Feels ‘wobbly’. Frequently associated with ACL injuries, often capsular tearing with this grade, swelling therefore present
Always local tenderness at insertion point

24. Collateral ligament injury
MCL is a result of a valgus force
LCL tear is less common and due to a high-energy direct varus stress on the knee and often associated with PCL tear
Treatment is generally conservative, although bracing is required for more severe injuries.

25. Menisci Pain on palpation of the joint line Positive McMurray’s test:
The knee is flexed and at various stages of flexion the tibia is internally and externally rotated
Pain and a ‘clunk’ make this test positive
Joint effusion
Pain on squatting (especially if posterior horn is involved)
Restricted ROM
MRI is investigation of choice

26. Meniscal injury Generally a twisting injury
Doesn’t have to be a quick injury
Degree of pain associated with an acute injury can vary dramatically.
Sometimes a tearing sensation will be felt
Sometimes pain is of late onset... Up to 24 hours later
Small tears may also occur with minimal trauma in the older athlete as a result of degenerative changes
Surgical indications include:
Inability to continue playing
Locked knee or severe lack of ROM, particularly EOR flexion
Palpable clunk on McMurray’s Test
Associated ACL tear
No change after 3 weeks post-injury

27. Patella and tendon
Assess the patella in 30° knee flexion, push the patella laterally, if the patient has apprehension, consider a dislocating patella
Pain infrapatella is usually the tendon (or can be bursal)
Fractured patella can occur due to direct trauma or through quadriceps avulsion.
In adolescents consider Osgood Schlatter’s Disease, particularly if a prominent tibial tubercle. This is a growth plate osteochondritis

28. Articular cartilage damage
Chondral damage can be a major cause of symptoms in the knee
Can be primary or secondary (ligamentous instability... ACL has high incidence of medial & lateral femoral condyle and tibial plateau chondral damage)

29. Anterior knee pain 20-40% of all MSK consultations in general practice
Generally AKP is due to:
Patellofemoral pain
Patella tendinopathy
Other causes can include:
Synovial plica
Pre-patella/ infrapatella bursitis
Fat pad impingement
Quadriceps tendinopathy
Patellofemoral instability

30. Patellofemoral pain Generally insidious onset, vague pain
Often secondary to an acute incidence
A diffuse ache exacerbated by loading eg stairs or running... Doesnt tend to have to be eccentric loading only.
Prolonged sitting can be painful
Worsening pain while exercising tends to be PFPS, while pain at start of exercise, and ceasing of exercise tends to be Patella tendinopathy
Previous injury to the knee predisposes one to PFPS
Any effusion around the knee >15ml of fluid will switch off VMO (major stabiliser of the knee) increasing the risk of adverse knee mechanics and therefore PFPS
Assess the patella position relative to the painfree side

31. Patella tendinopathy Mostly involves jumping/ multidirectional sports
Significantly more painful with eccentric loading rather than any other type of loading
Pain is inferior pole of the patella, or the tendon
Pain is always bad in the morning
Chronic tendinopathy can take 3-6 months to settle
Surgery is only indicated after a considered and lengthy conservative programme has failed

32. Lateral knee pain
Mostly due to Ilitobial band friction syndrome (ITBFS)
Repeated flexion/ extension at the knee causes ITB to rub on the lateral epicondyle
Training errors and biomechanical problems are the major causes of ITBFS
Occasionally biceps femoris tendon can become inflamed and tender
Superior tib-fib joint can also give lateral knee pain
OA of the lateral compartment
Nerve root irritation/ entrapment

33. Medial knee pain PFPS Medial meniscal injury
OA of the medial compartment
Pes anserinus bursitis
Referred pain

34. Posterior knee pain
Biceps femoris, gastrocnemius or popliteus tendinopathy
Referred pain
Baker’s cyst
Posterolateral corner injury
DVT
Claudication

35. Advice to you as GPs If it’s swollen, refer to orthopaedics
If it’s anterior knee pain, always refer to physio
If it’s giving way, refer to orthopaedics
A painless click is not a problem, as long as no locking or giving way is associated.
Kids with Osgood’s should rest when sore, and try to get strong when condition is stable
Rest will NEVER fix an injury.
Cycling (not standing on the pedals) is generally a knee friendly sport. Running is not.