MSK: Hip & Knee Flashcards
What are the hip adductors?
GAASP
Gracilis Adductor longus Adductor magnus Sartorius Pectineus
What are some of the extra-articular manifestations of RhA?
Ocular: keratoconjunctivitis sicca (most common), episcleritis, scleritis, corneal ulceration, keratitis, steroid-induced cataracts, chloroquine retinopathy
Respiratory: pulmonary fibrosis, pleural effusion, pulmonary nodules, bronchiolitis obliterans, methotrexate pneumonitis, pleurisy
IHD: RA carries a similar risk to T2DM
Systemic:
osteoporosis, infections (e.g. septic arthritis), depression
Less common:
Felty’s syndrome (RA + splenomegaly + low white cell count), Amyloidosis
What can cause a positive trendelenburg test and what does it test for?
Tests for hip abductor strength
Muscle weakness:
Weakness of gluteus medius minimus or Tensor Fascia Lata (TFL)
Joint issues: Hip OA Initially post Total Hip Replacement Hip instability and subluxation Lower back pain
Nerve issues:
Superior Gluteal Nerve Palsy
Chronic childhood conditions:
Legg-Calvé-Perthes Disease
Congenital hip dislocation
X-Ray changes for OA
Loss of joint space
Subchondral cysts
Subchondral sclerosis
Osteophyte formation at the joint margin
Clinical features of femoral nerve damage
Supplies the quadriceps and so you get weakness in knee extension
Loss of the patella reflex
Numbness of the thigh
Features of Ankylosing Spondylosis
Anterior uveitis Apical fibrosis AV node block Aortic regurgitation Amyloidosis Achilles tendonitis
What are the four main types of knee replacement?
Total knee replacement (bicompartmental)
Unicompartmental (partial) knee replacement
Kneecap replacement (patellofemoral arthroplasty)
Complex/revision knee replacement
What are some causes of apparent shortening of the leg and true shortening of leg length?
True Shortening
e.g. NOF Hip dislocation Growth disturbance of tibia/fibula Osteomyelitis, #s Surgery: e.g. THR SUFE Perthes’ disease
Apparent (problem above the hip)
Scoliosis
What are the features of OA in the hip?
± Trendelenberg gait or +ve Test Pain Stiffness ↓ ROM: esp. internal rotation Fixed flexion deformity
What are some of the surgical options for knee OA?
Arthroscopic Washout Realignment Osteotomy Arthroplasty Arthrodesis Microfracture
What are the types of hip arthroplasty?
THR: Replace femoral head, neck and acetabulum
Hemi-arthroplasty: Replace femoral head and neck only (can be unipolar or bipolar)
Resurfacing: replacement of the femoral head
What techniques are used for Hip arthroplasty?
Posterior approach:
Access joint and capsule posteriorly, reflecting of the short external rotators.
Gives good access
May have higher dislocation rate
Sciatic N. may be injured → foot drop
Anterolateral Approach
Incision over greater trochanter, dividing fascia lata.
Abductors are reflected to access joint capsule.
May have lower dislocation risk
Sup. Gluteal N. may be injured → Trendelenberg gait
Benefits and disadvantages of hip resurfacing
Advantages
Metal-on-metal bearings wear less
Larger head → ↓ dislocation / ↑ stability
Preserve bone stock making revision easier
Disadvantages
Cobalt and chromium metal ion release may cause pathology (e.g. leukaemia)
Risk of NOF # if mal-positioned
Indications for a hip resurfacing procedure
May be used in young (<65), active people who are expected to outlive the replacement.
Surgical management of RA in the knee
Indicated in failed medical Mx Synovectomy and debridement (can be done arthroscopically) Removal of pannus and cartilage Supracondylar osteotomy Total knee arthroplasty
Causes of fixed flexion deformity in the hip
Osteoarthritis
#NOF
Causes of knee effusion
Synovial fluid: synovitis (inflammatory arthritis)
Blood:
90% = ACL rupture
PCL rupture, intra-articular #, meniscal tear
Bleeding diathesis
Pus: septic arthritis
Definition of osteoarthritis
Degenerative joint disorder in which there is a progressive loss of hyaline cartilage and new bone formation at the joint surface and its margin.
X-Ray changes of RA
- Soft tissue swelling
- Periarticular osteopenia
- Periarticular erosions
- Severe deformity
- Joint space narrowing
Complications of Hip Arthroplasty
Immediate
Nerve injury
Fracture
Cement reaction
Early
DVT: up to 50% w/o prophylaxis
Deep infection: 0.5-1.5%
Must remove metalwork before revision.
Dislocation (3%): squatting and adduction
Late Loosening: septic or aseptic Leg length discrepancy Metalosis Revision: most replacements last 10-15yrs Peri prosthetic fracture
Complications of Knee arthroplasty
Immediate
Fracture
Cement reaction
Vascular injury (superficial femoral artery + (Popliteal and genicular vessels)
Nerve injury (peroneal nerve → foot drop (1%))
Early
DVT
Deep infection: 0.5-15%
Late
Loosening: septic or aseptic
Periprosthetic #s
↓ ROM and instability (due to loss of ACL)
What are some ddx of knee locking?
Meniscal tear
Cruciate ligament injury
Osteochondritis dissecans: adolescents
Loose body
Describe the ACL repair
Gold-standard is autograft repair
Usually semitendinosus ± gracilis (can use patella)
Tendon threaded through heads of tibia and femur and
held using screws.
What is meant by charcots joints?
Progressive destructive joint arthropathy
Secondary to disturbance of sensory innervation to the joint
Painless deformed joint resulting from repetitive minor
trauma.
What are the four phases of gait?
- Initial contact / heel strike
- Stance
- Toe off
- Swing
What are the three compartments of the knee?
Medial
Lateral
Patello femoral
Indications for total knee replacement
Traumatic injury
OA (refractory to medical Mx)
RA (refractory to medical Mx)
Hip examination: When doing active flexion which hip do you stabilise?
Ipsilateral: flexion, extension, internal and external rotation
Contralateral: hip abduction and adduction
Which patients should you not perform Thomas’s test in?
Hip replacement patients
What would you expect in a positive patellar tap?
Empty the suprapatellar pouch
If there is an effusion the patellar will float up and when you press down there would be a knock
How do you test meniscal damage?
McMurrays
Medial rotation: lateral meniscus
Lateral rotation: medial meniscus
Classification of fractures
1) Traumatic
- direct
- indirect (fall on out stretched hand)
- avulsion (ligament pulling off bone)
2) Stress
3) Pathological
Describing an X-Ray
Patient details
Location
Soft tissue: open/ closed?
Displacement:
- translation (horizontal movement)
- angulation (movement of the fracture from its normal
angle)
- dislocation (distally, proximally etc)
Pieces: comminuted
Pattern: Incomplete, transverse, oblique, spiral, impacted
When would you do an ORIF?
- Comminuted fractures
- Open fractures
- Intra-articular fracture (because synovial fluid contains collagenase enzymes that stop bone healing)
- Failure
Complications of fractures
Early:
- compartment syndrome
- visceral damage
- neurovascular damage
Late:
- avascular necrosis
- malunion
- OA of the joint
- reduced mobility
RF for OA
Genetics
Unmodifiable: female, bone density, age
Modifiable: obesity
Biomechanical: repetitive use of a joint
Surgical Management of OA
Arthroscopic washouts Arthroplasty Microfractures Osteotomy Athrodesis
X-ray you would request for the knee
AP
Lateral
Skyline (dislocated patellar)
What are the muscles used for hip abduction?
Gluteus minimus
Gluteus medius
Tensor Fascia Lata
How would a hip dislocation present?
Posterior dislocation: Accounts for 90% of hip dislocations. The affected leg is shortened, adducted, and internally rotated.
Anterior dislocation: The affected leg is usually abducted and externally rotated.
What is a Baker’s cyst?
Baker’s cysts are not true cysts but distension of the gastrocnemius-semimembranosus bursa.
Primary: no underlying pathology, typically seen in children
Secondary: underlying condition such as osteoarthritis, typically seen in adults
Surgery in RA
Debridement
Removal of pannus and cartilage
Supracondylar osteotomy
TKA
How would L3 nerve root compression present?
Sensory loss over anterior thigh
Weak quadriceps
Reduced knee reflex
Positive femoral stretch test
How would L4 nerve root compression present?
Sensory loss anterior aspect of knee
Weak quadriceps
Reduced knee reflex
Positive femoral stretch test
How would L5 nerve root compression present?
Sensory loss dorsum of foot
Weakness in foot and big toe dorsiflexion
Reflexes intact
Positive sciatic nerve stretch test
How would S1 nerve root compression present?
Sensory loss posterolateral aspect of leg and lateral aspect of foot
Weakness in plantar flexion of foot
Reduced ankle reflex
Positive sciatic nerve stretch test
What are you looking for from the front in a hip exam?
Scars
Pelvic tilt
Quadriceps wasting
What are you looking for from the side in a hip exam?
Lumbar lordosis
Knee flexion
Foot arches
What are you looking for from behind in a hip exam?
Scoliosis
Iliac crest alignment
Gluteal muscle bulk
What are you looking for from the front in a knee exam?
Quadriceps bulk
Knee swelling and deformity
Foot deformity
What are you looking for from the side in a knee exam?
Knee flexion
Foot arches
Toe deformity
What are you looking for from behind in a knee exam?
Iliac crest alignment
Gluteal muscle bulk
Popliteal swelling
Hindfoot abnormality
What does posterior sag indicate?
Rupture of the PCL
Surgical mx of a displaced subcapital NOF?
Hemiarthroplasty or THR
Surgical mx of a non-displaced intracapsular NOF?
Cannulated hip screws
Can consider hemi or THR
Surgical mx of an intertrochanteric or basocervical NOF?
Dynamic Hip Screw (or short IM nail)
Surgical mx of a sub-trochanteric NOF?
Anterograde Intramedullary Femoral Nail
Tool to classify OA Progression?
WOMAC score
What is the Unhappy Triad of O’Donoghue
- ACL
- MCL
- Medial Meniscus
Usually occurs at the same time
What is the normal angle of hip flexion?
120 (acute angle 60)
What is the normal angle of hip internal and external rotation?
45 degrees
What is the normal angle of hip abduction?
45 degrees
What is the normal angle of hip adduction?
25 degrees
What is the normal angle of hip extension?
20 degrees
What are the hip flexors?
Psoas Iliacus Sartorius Pectineus Adductor longus and brevis Rectus femoris
What are the hip extensors?
Gluteus maximus Hamstrings: - semitendinosis - semimembranosus - biceps femoris
What are the hip abductors?
Gluteus medius
Gluteus minimus
Tensor fascia lata
What are you looking for in the front for the knee exam?
Varus deformity
Valgus deformity
Hyperextension
Fixed flexion deformity
What is the normal angle of flexion of the knee?
40 degrees acute
What is the normal angle of extension of the knee?
<10 degrees
What are the knee flexors?
- semitendinosis
- semimembranosus
- biceps femoris
What are the knee extensors?
Rectus femoris
Vastus lateralis
Vastus intermedius
Vastus medialis
3 compartments of the knee?
Medial
Lateral
Patellofemoral
Indications for a cemented hip replacement?
Irradiated bone
Osteopenic/osteoporotic bone
Abnormally wide femoral canal
Kocher criteria for septic arthritis?
Non weight-bearing
Temp > 38.5°C
ESR >40mm/hr
WBC >12,000 cells/mm3