Orthopaedic Knee Conditions

Question 1

Meniscal tear: prognosis

Answer 1

• UNLIKELY to HEAL = as GENERALLY OLDER PT. AFFECTED & they have POORER BLOOD SUPPLY

	○ BLOOD SUPPLY to the MENISCUS RETREATS as WE AGE (> 19yrs = AVASCULAR)
	○ IF IN RED ZONE = MAY HEAL

Question 2

Meniscal tear: presentation

Answer 2

• PAIN = due to PULLING SENSATION - NOT CARTILAGE ITSELF
  
  • CLICKING = NOT SPECIFIC
  • LOCKING = CANNOT STRAIGHTEN by ITSELF, MORE SPECIFIC
  • INTERMITTENT SWELLING = LOTS of FLUID to try & HEAL it, V. OBVIOUS as SO SUPERFICIAL - IF LOTS of FLUID, IT MAY NOT be a TEAR

Question 3

Meniscal tear: aetiology

Answer 3

• ACUTE = TWISTING esp. in DEEP FLEXION
  
  • DEGENERATIVE = OA
  • MEDIAL MENISCI TEARS MORE COMMON = as it’s a MORE FIXED STRUCTURE

Question 4

Meniscal tear: pathophysiology

Answer 4

• ACUTE = more a SINGLE TEAR
  
  • DEGENERATIVE = as CARTILAGE starts to DEGENERATE = LESS SMOOTH SURFACE, FRONDS of CARTILAGE appear, WEAR & TEARS occurs, LITTLE FLAPS & PIECES COME OFF = BONE GRINDS ON BONE (ARTHRITIC CHANGES)

Question 5

Meniscal tear: investigations/diagnosis

Answer 5

ON/E:
LOOK - effusion, patellar tap
FEEL - tender joint line at point of tear esp. in medial tear
MOVE - mechanical block to movement

○ OA = SLOW MOVEMENT + poss. LIMITED ROM
○ MENISCAL TEAR = NORMAL VELOCITY, CANNOT GO FURTHER BEYOND SPECIFIC POINT (JAMMING)

• MCMURRAY’S TEST +VE = DEEP FLEX KNEE, ROTATION, AXIAL PRESSURE, then EXTEND KNEE = will CLICK IF TEAR PRESENT
• FAIL DEEP SQUAT = TEAR if OFTEN in POSTERIOR MEDIAL THIRD - FLAP FLIPS INTO JOINT; DEEP FLEXION DIFFICULT so pt. UNABLE TO SQUAT ON AFFECTED SIDE

• THASSALY’S TEST +VE = HAND ON CHAIR, get pt. to BEND KNEE to 120°, TWIST - try to RECREATE MOVEMENTS that CAUSED TEAR

IMAGING:

* X-RAY = ARTHRITIS, #
* MRI = MOST SENSITIVE TEXT, HIGH FALSE +VE RATE

• USE TESTS in CONJUCTION w/ CLINICAL Hx to determine LVL of INTERVENTION

Question 6

OA: pathophysiology

Answer 6

• DEGENERATIVE CHANGE of SYNOVIAL JOINTS

	○ PROGRESSIVE LOSS of ARTICULAR CARTILAGE
	○ 2ndary BONY CHANGES

* PRIMARY = DEGENERATIVE CHANGES w/ NO PREDISPOSING FACTORS
* SECONDARY = PREDISPOSING FACTORS e.g. POST-TRAUMATIC, POST-OPERATIVE, POST-INFECTIVE, MALPOSITION, MECHANICAL INSTABILITY, OSTEOCHONDRITIS DISSECANS

	○ OA ASS. W/: INCREASED BMI, GENETIC FACTORS, AGE, OCCUPATION

Question 7

OA: epidemiology

Answer 7

• WOMEN esp. if > 55yrs are at GREATER RISK

Question 8

OA: presentation

Answer 8

• WORSENING PAIN + STIFFNESS of AFFECTED JOINT

	○ PAIN = on INITIATING MOVEMENT
	○ STIFFNESS = FOLLOWS INACTIVITY, OFTEN RESOLVES < 30mins
	○ LIMITING EVERYDAY LIFE

* SWELLING
* VARUS DEFORMITY

Question 9

OA: investigations/diagnosis

Answer 9

ON/E:

* REDUCED ROM w/ CREPITUS during both ACTIVE & PASSIVE MOVEMENTS
* JOINT DEFORMITY & BONY OVERGROWTH from OSTEOPHYTES

IMAGING: X-RAY

Question 10

OA: management

Answer 10

• NSAIDs
  
  • PHYSIOTHERAPY = QUADRICEPS STRENGTHENING EXERCISES
  • WGT. LOSS
  • LOCAL STEROID INJECTIONS for SHORT-TERM USE

OSTEOTOMY esp. in YOUNG ACTIVE PT. as it can delay TOTAL KNEE REPLACEMENT for up to 10yrs

Question 11

ACL injury: key anatomy

Answer 11

• COURSE = runs from BWTN TIBIAL EMINENCES to LATERAL WALL of INTERCONDYLAR NOTCH of FEMUR
  
  • BLOOD SUPPLY = MIDDLE GENICULATE ARTERY
  • INNERVATION = POSTERIOR ARTICULATE NN. (branch of TIBIAL NN.) for JOINT PROPRIOCEPTION - STABILITY

Question 12

ACL injury: function

Answer 12

to = ANTERIOR TRANSLATION of TIBIA RELATIVE to FEMUR

• SECONDARY RESTRAINT to = TIBIAL ROTATION & VARUS/VALGUS STRESS

Question 13

ACL injury: aetiology

Answer 13

• NON-CONTACT PIVOT INJURY = BAD LANDING MECHANICS

* ACUTE TEAR - VALGUS MOVEMENT causes ACL TEAR, LATERAL MENISCUS LIKELY to TEAR
* May have MENISCAL TEAR - due to STRESSES PLACES on it due to INSTABILITY of KNEE & AMOUNT of SHEAR & MOVEMENT it has to DEAL w/

Question 14

ACL injury: epidemiology

Answer 14

• F > M = 4.5 : 1

* LANDING MECHANICS causes NEUROMUSCULAR ACTIVATION PATTERNS

Question 15

ACL injury: presentation

Answer 15

• Heard POP/CRACK = when landing badly + COLLAPSE
  
  • IMMEDIATE SWELLING = 70%○ HAEMARTHROSIS = SNAPPED ACL BLOOD SUPPLY - ACL has a rlly good blood supply
  • UNABLE to CONTINUE PLAYING

    ○ CAN WALK in STRAIGHT LINE; KNEE TOO WOBBLY - as everything is in the wrong place, & so CANNOT TWIST & TURN

  • DEEP PAIN
  • FEELS ODD = KNEE in WRONG PLACE

Question 16

ACL injury: investigations/diagnosis

Answer 16

ON/E:
LOOK - effusion if recent injury

MOVE - ANTERIOR DRAW, LACHMANN’S TEST, PIVOT SHIFT (not in clinic)

IMAGING:

* X-RAY = SEGOND # (AVULSION # of ANTEROLATERAL LIGAMENT), PATHOGNOMIC for ACL TEAR
* MRI = ACL, MCL, MENISCII (LATERAL - SIMULTANEOUS w/ ACL TEAR in 48%; MEDIAL - 2ndary to SHEAR FORCE from CHRONIC INSTABILITY)

Question 17

ACL injury: management

Answer 17

Non-operative - FOCUSED QUADRICEP PROGRAMME

OPERATIVE - ACL RECONSTRUCTION +/- partial menisectomy +/- ligament repair/augmentation, can use hamstring graft/quadriceps tendons/patellar tendons/donor tendons

Question 18

MCL injury: management

Answer 18

Non-operative - majority

• REST
• NSAIDs
• PHYSIOTHERAPY e.g. QUADRICEPS STRENGTHENING
• BRACE for COMFORT

Operative

• For SEVERE TEARS, FAILED NON-OPERATIVE MANAGEMENT
• REPAIR/RECONSTRUCTION○ REPAIR = AVULSIONS - midsubstance tear w/ good tissue, an INTERNAL BRACE holds MCL TOGETHER○ RECONSTRUCTION = DAMAGED TISSUE, usually w/ semitendinosus

Question 19

MCL injury: key anatomy

Answer 19

SUPERFICIAL - PRIMARY RESTRAINT to VALGUS STRESS

DEEP - contributes in FULL KNEE EXTENSION (attaches to medial meniscus + continuous w/ joint capsule)

Question 20

MCL injury: aetiology + ass. injuries

Answer 20

• SEVERE VALGUS STRESS - usually CONTACT-RELATED (HIT at MEDIAL SIDE of KNEE)

ass. w/: ACL TEAR, MENISCAL TEAR

Question 21

MCL injury: presentation

Answer 21

• Heard POP/CRACK
  
  • PAIN ++ = MEDIAL SIDE
  • UNABLE to CONTINUE PLAYING
  • BRUISING = MEDIAL KNEE
  • LOCALISED SWELLING

Question 22

MCL injury: investigations/diagnosis

Answer 22

ON/E:

LOOK - medial swelling, bruising
FEEL - tender medial joint line, tender femoral insertion of MCL
MOVE - pain in full extension, opening on valgus stress

IMAGING:

* X-RAY = may be NORMAL, CALCIFICATION at FEMORAL INSERTION (PELLEGRINI-STIEDA) - CHRONIC INJURY
* MRI = MODALITY of CHOICE, ASSESS LOCATION & SEVERITY of INJURY, IDENTIFY OTHER PATHOLOGIES e.g. CARTILAGE DAMAGE, CONDYLES, MENISCUS

	○ MOST COMMON SITE = FEMORAL INSERTION

Question 23

Osteochondritis dissecans: pathophysiology

Answer 23

• PATHOLOGICAL LESION affecting ARTICULAR CARTILAGE & SUBCHONDRAL BONE
  
  • SIMILAR to AVN

Question 24

Osteochondritis dissecans: aetiology

Answer 24

• HEREDITARY
  
  • TRAUMATIC
  • VASCULAR = ADULT FORM

Question 25

Osteochondritis dissecans: location

Answer 25

• KNEE = MOST COMMON, POSTEROLATERAL ASPECT of MEDIAL FEMORAL CONDYLE (70%)

Question 26

Osteochondritis dissecans: presentation

Answer 26

• ACTIVITY-RELATED PAIN (usually TEENAGERS) = POORLY LOCALISED
  
  • RECURRENT EFFUSIONS = SWELLS UP ALL THE TIME (intermittent swelling is poss. meniscal tear)
  • MECHANICAL SYMPTOMS = LOCKING, BLOCK to FULL MOVEMENT
  • SIMILAR TO MENISCAL TEAR PRESENTATION = MENISCAL TEAR NOT V. PAINFUL & CAN MOVE ~; this is V. PAINFUL

Question 27

Osteochondritis dissecans: investigations/diagnosis

Answer 27

ON/E:
LOOK - effusion
FEEL - localised tenderness
MOVE - stiffness, block to movement, Wilson’s test

IMAGING:
• X-RAY = ADD in TUNNEL VIEW (FLEXED 30 - 50°) - for POSTERIOR PART of CONDYLE

• MRI = LESION SIZE, STATUS of CARTILAGE & SUBCHONDRAL BONE, SIGNAL INTENSITY (OEDEMA suggests INSTABILITY of FRAGMENT)

Question 28

Osteochondritis dissecans: management

Answer 28

Non-operative:
• RESTRICTED WGT.-BEARING = gives TIME FOR FAULT to HEAL by RESTRICTING DEEP FLEXION
• ROM BRACE

Operative:
• ARTHROSCOPY = SUBCHONDRAL DRILLING, FIXATION of LOOSE FRAGMENT

• OPEN FIXATION