Hip Flashcards
Hip dislocations should be reduced within what time frame and why
within 6 h to decrease risk of AVN of the femoral head
Hip precautions following dislocation
no extreme hip flexion, adduction, internal or external rotation for 6 weeks post-reduction
Concurrence of hip dislocations and fractures
up to 50% of patients with hip dislocations suffer fractures elsewhere at the time of injury
Anterior hip dislocation mechanism
posteriorly directed blow to knee with hip widely abducted
Anterior hip dislocation clinical features
shortened, abducted, externally rotated limb
Anterior hip dislocation treatment
■ closed reduction under conscious sedation/GA
■ post- reduction CT to assess joint congruity
Posterior hip dislocation mechanism
severe force to knee with hip flexed and adducted
■ e.g. knee into dashboard in MVC
Posterior hip dislocation clinical features
shortened, adducted, internally rotated limb
Posterior hip dislocation treatment
■ closed reduction under conscious sedation/GA only if no associated femoral neck fracture or ipsilateral displacement
■ ORIF if unstable, intra-articular fragments, or posterior wall fracture
■ post-reduction CT to assess joint congruity and fractures
■ if reduction is unstable, put in traction x 4-6 wk
Rochester method to reduce posterior dislocations
- Patient lying supine with hip and knee flexed on injured side
- Surgeon stands on patient’s injured side
- Surgeon passes one arm under patient’s flexed knee, reaching to place that hand on patient’s other knee (thus supporting patient’s injured leg)
- With other hand, surgeon grasps patient’s ankle on injured side, applying traction, while assistant stabilizes pelvis
- Reduction via traction, internal rotation, then external rotation once femoral head clears acetabular rim
Complications for all hip dislocations
- post-traumatic OA
- AVN of femoral head
- fracture of femoral head, neck, or shaft
- sciatic nerve palsy in 25% (10% permanent)
- HO
- thromboembolism – DVT/PE
Hip fracture clinical features
- acute onset of hip pain
- unable to weight-bear
- shortened and externally-rotated leg
- painful ROM
Xray features of subcapital hip fractures
- Disruption of Shenton’s line (a radiographic line drawn along the upper margin of the obturator foramen, extending along the inferomedial side of the femoral neck)
- Altered neck-shaft angle (normal is 120-130°)
DVT prophylaxis in hip fractures
LMWH (i.e. enoxaparin 40 mg SC bid), fondaparinux, low dose heparin on admission, do not give <12 h before surgery
Femoral neck (subcapital) fracture definition
Intracapsular
Femoral neck (subcapital) fracture mechanism
Young: MVC, fall from height
Elderly: fall from standing, rotational force
Femoral neck (subcapital) fracture special clinical features
Same as general
Femoral neck (subcapital) fracture investigations
Xray
AP hip
AP pelvis
Cross table lateral hip
Femoral neck (subcapital) fracture complications
DVT
Non-union
AVN
dislocation
AVN of femoral head
- Distal to proximal blood supply along femoral neck to head (medial and lateral femoral circumflex arteries)
- Susceptible to AVN if blood supply disrupted
Etiology: femoral neck fracture, chronic systemic steroid use, SCFE, Legg-CalvéPerthes, SLE, RA
Intertrochanteric fracture stable vs unstable
Stable: intact posteromedial cortex
Unstable: non-intact posteromedial cortex
Intertrochanteric fracture definition
Extracapsular fracture including the greater and lesser trochanters and transitional bone between the neck and shaft
Intertrochanteric fracture mechanism
Same as femoral neck fracture Direct or indirect force transmitted to the intertrochanteric area
Intertrochanteric fracture special clinical features
Ecchymosis at back of upper thigh
Intertrochanteric fracture investigations
X-Ray: AP pelvis, AP/lateral hip
Intertrochanteric fracture treatment
Closed reduction under fluoroscopy then dynamic hip screw or IM nail
Intertrochanteric fracture complications
DVT,
varus displacement of proxim l fragment,
malrotation,
nonunion,
failure of fixation device
Subtrochanteric hip fracture definition
Fracture begins at or below the lesser trochanter and involves the proximal femoral shaft
Subtrochanteric hip fracture mechanism
Young: high energy trauma Elderly: osteopenic bone + fall, pathological fracture
Subtrochanteric hip fracture special clinical features
Ecchymosis at back of upper thigh
Subtrochanteric hip fracture investigations
X-Ray: AP pelvis, AP/lateral hip and femur
Subtrochanteric hip fracture treatment
Closed/open under fluoroscopy, then plate fixation or IM nail
Subtrochanteric hip fracture complications
Malalignment
non-union
wound infection
Garden classification of femoral neck fractures
Type I Displacement none Extent incomplete Alignment valgus or neutral Trabeculae malaligned Tx internal fixation to prevent displacement (valgus impacted fracture)
Type II Displacement None Extent Complete Alignment Neutral Trabeculae aligned Tx interal fixation to prevent displacement
Type III Displacement some Extent complete Alignment varus Trabeculae malaligned Tx young - ORIF, elderly hemi/total hip arthroplasty
Type IV Displacement complete Extent complete Alignment varus Trabeculae aligned Treatment young ORIF, elderly hemi/total hip arthroplasty
Arthritis of the hip etiology
OA, inflammatory arthritis, post-traumatic arthritis, late effects of congenital hip disorders, or septic arthritis
Arthritis of the hip clinical features
pain (groin, medial thigh) and stiffness aggravated by activity better with rest in OA
- RA: morning stiffness >1 h, multiple joint swelling, hand nodules
- decreased ROM (internal rotation is lost first)
- crepitus
- effusion
- ± fixed flexion contracture leading to apparent limb shortening (Thomas test)
- ± Trendelenburg sign
Arthritis of the hip investigations
X-ray: weight-bearing views of affected joint
■ OA: joint space narrowing, subchondral sclerosis, subchondral cysts, osteophytes
- RA: osteopenia, erosion, joint space narrowing, subchondral cysts
- blood work: ANA, RF
Arthritis of the hip treatment
• non-operative
■ weight reduction, activity modification, physiotherapy, analgesics, walking aids
• operative
■ indication advanced disease
■ realign = osteotomy; replace = arthroplasty; fuse = arthrodesis
• arthroplasty is standard of care in most patients with hip arthritis
• complications with hip arthroplasty:
component loosening
dislocation,
HO,
thromboembolism,
infection,
neurovascular injury,
limb length discrepancy
Hip dislocation post-total hip arthroplasty occurrence
occurs in 1-4% of primary THA and 10-16% of revision THAs
Hip dislocation post-total hip arthroplasty risk factors
neurological impairment
post-traumatic arthritis
revision surgery
substance abuse
Hip dislocation post-total hip arthroplasty mechanism
THA that is unstable when hip is flexed, adducted, and internally rotated, or extended and externally rotated (avoid flexing hip >90° or crossing legs for ~6 wk after surgery)
Hip dislocation post-total hip arthroplasty investigations
X-ray: AP pelvis, AP and lateral hip
Hip dislocation post-total hip arthroplasty treatment
• non-operative
■ closed reduction: external abduction splint to prevent hip adduction (most often)
• operative
■ indication: 2 or more dislocations with evidence of polyethylene wear, malalignment, hardware failure
■ revision THA
■ conversion to hemiarthroplasty with a larger femoral head
■ resection arthroplasty is a last resort
Hip dislocation post-total hip arthroplasty complications
- sciatic nerve palsy in 25% (10% permanent)
- HO
- infection
DVT prophylaxis in elective THA
(continue 10-35 d post-operative) Fondaparinux, low molecular weight heparin, or warfarin
