Hip And Femur Flashcards
Radiographic evaluation of femoral head fxs: 2 views
AP and Judet-45 degree oblique
Classification name and system for femoral head fxs
Pipkin
Type 1: hip dislocation with fracture of the fem head INFERIOR to the fovea capitis femoris
Type 2: “….” SUPERIOR to the fovea capitis femoris
Type 3: type 1 or 2 injury with fx of femoral neck
Type 4: type 1 or 2 injury with fx of acetabular rim
Tx for Pipkin type 3 fx
Young pt: emergent ORIF for fem neck followed by internal fixation for fem head. Anterolateral approach (Watson-Jones)
Old pt with displaced femoral neck: prosthesis
- Poor prognosis, 50% AVN
Tx for Pipkin type 4
Acetabular fx dictates approach. Femoral head should be internally fixed for early motion of hip
3 ligaments of the hip capsule:
1: Ileofemoral (Y ligament of Bigelow) - anterior
2: Pubofemoral - anterior
3: Ischiofemoral - posterior
2 classification systems used for femoral neck fxs
1: Pauwel
2: Garden
Radiographic views for femoral neck fx (3)
AP pelvis, AP hip and cross table lateral
Garden classification system for femoral neck fxs:
Based on the degree of valgus displacement
Type 1: incomplete/valgus impaction
Type 2: complete and nondisplaced on AP and lateral views
Type 3: complete with partial displacement; trabecular pattern of the femoral head does not line up with that of the acetabulum
Type 4: completely displaced
Tx of fatigue/stress femoral neck fractures: tension sided vs compression sided
Tension: superior-lateral portion of neck - at significant risk for displacement. In situ screw fixation recommended
Compression: inferior neck (haze of callus at inferior neck) - protective crutch ambulation 2/2 minimal risk for displacement
Tx of impacted/nondisplaced femoral neck fractures
In situ fixation with 3 cancellous screws to prevent displacement (up to 40% will displace w/o internal stabilization); exception = pathologic fxs, severe OA/RA, Paget may require prosthesis
Tx of displaced femoral neck fractures in elderly and young pts
Elderly: high functioning - THA; low demand/poor bone quality - hemi with unipolar prosthesis
Young: ORIF with multiple screw fixation (3 in inverting triangle; avoid being distal to lesser) or sliding screw sideplate device with second pin/screw to control rotation (consider DHHS if basicervical)
Unlike femoral neck fxs, intertroch fxs do not have as many problems with nonunion and osteonecrosis. Why?
Extracapsular - occur in cancellous bone and good blood supply
What are the 3 deforming muscular forces with intertroch fxs - produce shortening, ER, and varus position
Abductors: displace greater troch laterally and proximally
Iliopsoas: lesser troch medially and prox
Hip flexors, extensors, adductors: distal frag prox
Surgical tx options for intertroch fxs?
1: sling hip screw
2: IM hip screw nail (cephalomedullary)
Mechanism and Tx of isolated greater troch fxs
Mechanism: eccentric muscle contraction or direct blow; Nonop in elderly. Young active pt: ORIF with tension band wiring or plate and screw fixation with a hookplate
Why are basicervical fxs treated like intertroch fxs?
Extracapsular, lack of cancellous interdigitation seen in intertroch region makes them more susceptible to rotation
Classification system used for intertrochanteric fractures
Evans - based on prereduction and postreduction stability –> convertibility of an unstable fx config to a stable reduction
Unstable intertrochanteric fx pattern
Greater comminution of Posteromedial cortex; subtroch extension or reverse obliquity pattern
Most important technical aspects of screw insertion with intertroch fxs
1: placement within 1 cm of subchondral bone for secure fixation.
2: central position in the femoral head
Russel-Taylor subtroch fx classification: (may be obsolete now)
Importance: guide to implant choice between first and second generation cephalomedullary nails
Type 1: fractures with an intact piriformis fossa:
Type 1A: lesser troch attached to prox frag
Type 1B: lesser is DETACHED from prox frag
Type 2: fractures that extend into the piriformis fossa
Type 2A: stable medial construct (Posteromedial cortex)
Type 2B: comminution of the piriformis fossa and lesser troch
Tx of subtroch fx:
IM nail or 95 degree fixed angle plate; proximal femur precontoured locking plates are a new alternative to traditional fixed angle plates and screws
Tx of isolated greater troch fxs:
Nonop in elderly. Young active pt: ORIF with tension band wiring or plate and screw fixation with a hookplate
Standard of care surgically for femoral shaft fxs: Should take place within 24 hours!
IM nail - should be statically locked to maintain femoral length and control rotation
Indications for use of external fixation for femoral shaft fxs: 3
1: temporary bridge to IM nailing (up to 2 weeks)
2: ipsilateral artery damage that requires repair
3: severe soft tissue contamination in whom a second debridement would be limited by other devices
Average angulation and direction of anatomic axis (shaft of femur and knee joint)
Valgus angulation of 9 degrees (7-11 degrees)
Stable fx pattern for intertrochanteric
Posteromedial cortex remains intact and has little comminution
Tx of stable, nondisplaced fxs of the distal femur:
Nonop tx of displaced fxs:
Mobilization of the extremity in a hinged knee brace, with partial weight bearing.
Non op: 6-12 week period of casting with acceptance of resultant deformity followed by bracing. Objective is restoration of knee joint axis to a normal relationship with the hip and ankle
3 classification systems for subtroch fxs
1: Fielding
2: Seinsheimer
3: Russell-Taylor
Two types of injury that are present in roughly 50% of femoral shaft fractures:
Ligamentous and meniscal injuries
Blood supply to the cortex of the femur:
Outer 1/3 supplied by periosteal vessels. Inner 2/3 supplied by endosteal
Following most femoral shaft fxs, _____ vessels are disrupted and _____ vessels proliferate to act as the primary source of healing
Endosteal vessels are disrupted, periosteal vessels proliferate
Classification system for femoral shaft fxs based on fx comminution
Winquist and Hansen
Winquist and Hansen classification system for femoral shaft fxs:
Type 1: minimal or no displacement
Type 2: cortices of both fragments at least 50% intact
Type 3: 50-100% cortical comminution
Type 4: circumferential comminution with no cortical contact
General rule of thumb for skeletal traction of femoral shaft fxs
1/9 or 15% body weight of traction (usually 20-40 pounds)
Potentially negative effects of reaming before IM nail placement in femoral fxs: (4)
1: elevated IM pressures
2: elevated pulmonary artery pressures
3: increased fat emboli
4: increased pulmonary dysfxn
Potential advantages of reaming before IM nail placement in femur fxs (3)
1: ability to place larger nail
2: increased Union
3: decreased hardware failure
Site and mechanism of vascular injury in femoral shaft fxs
Tethering of the femoral artery at the adductor hiatus
Radiographic eval for distal femur fxs:
AP, lateral, two 45 degree oblique. Should include the entire femur. Consider traction views to view alignment
Classification system used for distal femur fractures
Neer - based on direction of displacement of distal fragments
Operative treatment option for distal femur fractures (5):
1: young adults with good bone stock in unicondylar fxs = INTERFRAG SCREWS
2: to control alignment one of these 3 methods = 95 degree condylar blade plate, dynamic condylar screw (DCS), locking plates with fixed angled screws
3: IM nails: anterograde for supracondylar, retrograde for distal fixation
Classic appearance of patient with posterior hip dislocation vs anterior dislocation:
Post: flexion, internal rotation, adduction
Ant: marked external rotation, mild flexion, abduction
Radiographic images ordered with hip dislocation
AP pelvis and cross table lateral
What should you look for on the AP view of the pelvis when evaluating hip dislocations (5)
1: Femoral heads should appear similar in size
2: Joint spaces should be symmetric throughout
3: Shenton’s line should be smooth and continuous
4: Appearance of greater and lesser trochs for pathologic rotation; adduction vs abduction
5: femoral neck to rule out fracture
AP radiograph findings in posterior hip dislocation:
AP radiograph findings in anterior hip dislocation:
1: Affected femoral head appears smaller
2: Affected femoral head appears slightly larger
Thompson and Epstein Classification of Posterior Hip Dislocations:
Type 1: Dislocation w/ or w/o insignificant post wall frag
Type 2: Dislocation w/ single large post wall frag
Type 3: Dislocation w/ a comminuted post wall frag
Type 4: Dislocation w/ fx of acetabular floor
Type 5: Dislocation w/ fx of femoral head (Pipkin)
Epstein Classification of Ant. Hip Dislocations
Type 1: Superior dislocations, including pubic and subspinous
1A: No associated fx; 1B: Associated fx/impaction of femoral head; 1C: Associated fx of acetabulum
Type 2: Inferior dislocation, including obturator and perineal
2A: No assoc. fractures; 2B: assoc. fx/impaction of femoral head; 2C: assoc. fracture of acetabulum
Long-term prognosis worsens if reduction (open or closed) of a hip takes longer than ____?
12 hours
General reduction technique for hip dislocation?
Allis method?
General: in-line traction
Allis: traction applied in line, pt supine, dr standing above pt, assistant provides countertraction at pelvis. Increase traction force, increase flexion to 70 degrees, gentle rotational motions –> clunk
Indications for open reduction of hip dislocation (4)
1: irreducible by closed means; 2: nonconcentric reduction; 3: fx of acetabulum or femoral head requiring ORIF; 4: ipsilateral femoral neck fx
Management after closed or open reduction:
If reduction is concentric and stable: short period of bed rest followed by protective weight bearing for 4-6 weeks
Concentric and unstable: skeletal traction for 4-6 weeks followed by protective weight bearing
Most frequent long-term complication of hip dislocations; incidence much higher with acetabular and femoral head fxs
Posttraumatic Osteoarthritis
This injury occurs in 10-20% of hip dislocations, more common with posterior dislocations or post. displaced fracture frag
Sciatic nerve injury
This injury occurs in 25-75% of anterior hip dislocations
Femoral head fractures - impaction fractures usually on superior aspect of femoral head
Describe the set up for a cross-table lateral hip Xray
Patient supine, unaffected hip and knee flexed to 90, aim beam at groin so it is perpendicular to the femoral neck (not shaft)
What is the most common anatomic location for a femoral neck fracture?
Subcapital
Fraction reduction maneuver for Femoral Neck fxs
Hip flexion, gentle traction, external rotation to disengage the fragments; then slow extension and IR to achieve reduction. Confirm on AP and Lat XR
Guidelines for acceptable reduction of Fem Neck fx
AP view: valgus or anatomic alignment; Lat view: maintain anteversion while avoiding post translation
Radiographic eval for intertroch fxs
AP pelvis, AP and cross-table lateral hip; physician assisted internal rotation view possibly
Imaging study of choice to delineate nondisplaced or occult fxs (intertroch fxs)
MRI
Fracture characterized by line from medial cortex proximally to lateral cortex distally near intertroch region
Reverse Obliquity - tx like subtroch hip fractures
When would you use nonop tx in intertroch fxs
Pts with extreme medical comorbidities or demented nonambulators in mild pain
Describe the tip-apex distance used to determine lag screw position within the femoral head during intertroch repair
Expressed in mm, is the sum of the distance from the tip of the lag screw to the apex of the femoral head on both the AP and lat XR; the sum should be
% incidence of loss of fixation, most commonly in unstable fracture patterns, with fixation of intertroch fxs
4-12%
Advantages of an IM Hip screw nail vs Sling Hip screw (5)
Inserted in a closed manner with limited fracture exposure, decreased blood loss, less tissue damage; subjected to lower bending moment; limited fracture collapse
Most effective treatment in intertroch fxs with subtroch extension and reverse obliquity fxs
IM/cephalomedullary nail
When would you use a prosthetic replacement for intertroch fractures and what type would be used?
Failed initial ORIF and pts unsuitable for repeat internal fixation; a calcar replacement hemiarthroplasty
Best treatment for reverse obliquity intertroch fxs
Treated as subtroch fractures - either a 95 degree fixed angle implant or an IM nail device
Special consideration when treating basicervical fractures with an SHS or IMN
Use of supplemental antirotation screw or pin
Most common complication after fixing intertroch fx
Loss of fixation - up to 20% of unstable fx patterns; mots common cause is eccentric placement of the lag screw within the femoral head; others include severe osteopenia, improper reaming, inability to obtain stable reduction, excessive fx collapse, inadequate screw barrel engagement
What causes a malrotation deformity in intertroch fixation?
Internal rotation of the distal fragment at the time of internal fixation; consider plate removal and rotational osteotomy
Area of femur that classifies a subtroch fracture
From the lesser troch to 5 cm distal to lesser troch
% of subtroch fractures 2/2 pathologic fxs
17-35%
Initial management of subtroch fractures to limit further soft tissue damage and hemorrhage
Provisional splinting with traction pin until definitive fixation
Deforming muscle forces observed in subtroch fractures
Proximal frag: abduction by gluteus, external rotation by short rotators, flexion by psoa; Distal frag: pulled proximally and into varus by adductors
Radiographic eval of subtroch fxs
AP pelvis, AP and lat hip and femur; possibly contralateral femur to assess shortening in comminuted fxs
Considerations in tx of subtroch fxs with Interlocking nail (first gen vs second gen)
First gen (centromedullary) nail - subtroch fxs with intact trochs; 2nd gen - indicated for all fxs, especially with loss of posteromedial cortex, may be troch or piriformis starting types
Mechanism for loss of fixation with subtroch fxs:
1) Plate and screw devices:
2) Interlocked nails:
3) Cephalomed nails:
1) Plate: screw cutout in osteopenic pts
2) Interlocked: failure to lock the device statically, comminution of the entry portal, use of smaller diameter nails
3) CM nails: fatiguing through lag screw hole
Potential sites of vascular injury after femoral shaft fx (2)
Adductor hiatus and perforating vessels of profunda femoris
Muscular deforming forces of the femoral shaft (5)
Glute med and min: abduction
Iliopsoas: flexes and externally rotates
Adductors: axial and varus load via traction of distal frag
Gastroc: flexes distal frag
Fascia lata: acts as a tension band by resisting medial angulating forces of the adductors
Location of most pathologic femur fractures
Metaphyseal - diaphyseal junction (consider when fx is inconsistent with the degree of trauma)
Descriptive classification of femur fxs (pretty much what you should use to describe any fracture)
Open vs Closed Location: prox, mid, distal or isthmal, infraisthmal, supracondylar Pattern: transverse, spiral, oblique Comminuted, segmental, butterfly Angulation and rotational deformity Displacement: shortening or translation
Goals of skeletal traction (4)
Restore femoral length, limit rotational and angular deformities, reduce painful spasms, minimize blood loss into thigh
Locations of pinning for skeletal traction in femur fxs:
Direction of safe pin placement:
Distal femoral pins in extracapsular location, Prox tib pins at Tibial tubercle in bicortical location.
Safe pin placement from medial to lateral at distal femur (away from fem artery), from lateral to medial at prox tib (away from peroneal nerve)
Benefits of IM nailing femur fractures vs plate fixation (4ish)
IM location results in lower tensile and shear stresses on the implant than plate fixation. Less extensive exposure, lower infection rate, less quad scarring
General advantages of IM nailing femur fxs (4)
Early functional use, restoration of length and alignment with comminuted fxs, rapid and high union (>95%), low refracture rates
Advantage of a piriformis starting point in antegrade IM femur nail; if you use a troch starting point, what must be special about the nail
In line with the medullary canal of the femur.
Troch starting point: nail has to have valgus proximal bow to negotiate the off starting point axis
Relative indications for retrograde IM femur nailing (6)
Ipsilateral injuries (femoral neck, pertroch, acetabular, patellar, tibial shaft), bilateral femoral shaft fxs, morbidly obese pts, pregnant women, periprosthetic fx above TKA, ipsilateral through knee amputation
Indications for plate fixation of femur fractures (5)
Extremely narrow medullary canal, fxs adjacent to or through a previous malunion, obliteration of canal (infection or previously closed mgmt), fxs with proximal or distal extension, rapid femoral stabilization in a pt with an associated vascular injury (since there will be large exposure to fix vasculature)
When using plate fixation, how many screw holes do you want on each side of the fracture (femurs)
4-5 screw holes
Mgmt of femur fx in multiply injured pt
Early external fixation of long bone fxs followed by delayed IM nailing (limits inflammatory state post trauma)
Time frame for delayed union of a fx:
> 6 months
Define the supracondylar area of the femur
Zone between the femoral condyles and the junction of the metaphysis with the femoral shaft; distal 10-15 cm of the femur
Describe the anatomy of the distal femur from an axial view:
Distal femur is trapezoidal (condyles are wider posteriorly), anterior surface slopes downward from lateral to medial, the lateral wall inclines 10 degrees and the medial wall inclines 25 degrees
Characteristic displacement patterns from deforming forces from muscular attachments:
Gastroc: flexes the distal fragment, causing posterior displacement and angulation; Quad and hami: proximal traction causing shortening of lower extremity
Neer periprosthetic TKA classification system:
Type 1: Nondisplaced = 1 cm with lateral femoral shift displacement
Type 2b: Displaced > 1 cm with medial femoral shift displacement
Type 3: Displacement and comminuted
DiGioia and Rubash classification TKA periprosthetic
Group I: Extra-articular, nondisplaced = less than 5 mm displacement and/or less than 5 degrees angulation
Group II: Extra-articular, displaced (greater than 5 mm displacement and/or greater than 5 degrees angulation)
Group III: Loss of cortical contact or angulated (10 degrees); may have intercondylar or T-shaped component
What should you do when a distal femur fx is associated with an overlying laceration or puncture wound (2)
Inject >120 cc into the knee from a remote location to determine continuity with the wound. CT scan to observe for free air if the wound communicates
Radiographic eval of distal femur fxs
AP, lateral, and two 45 degree oblique radiographs; include the entire femur
What radiographic study should you consider in distal femur fractures with dislocation of the knee?
Arteriography - 40% of dislocations are associated with vascular disruption
Descriptive classification of distal femur fractures:
Open vs closed Location: supracondylar, intercondylar, condylar Pattern: transverse, spiral, oblique Articular involvement Comminuted, segmental, butterfly Angulation and rotational deformity Displacement: shortening or translation
Surgical options of Supracondylar fxs following TKA (3)
Retrograde IM nailing, Plate fixation, Revision arthroplasty
Post op mgmt following distal femur fixation
CPM device, PT with active ROM exercises and non-weight bearing with crutches 2-3 days after stable fixation, weight bearing around 6-12 weeks with radiographic evidence of healing
Most common post op complication seen in distal femur fxs
Loss of knee motion - results from scarring, quad damage, articular disruption; best prevented by anatomic reduction, early ROM, adequate pain control
Tx of Pipkin type 1 (non-weight bearing side)
If reduction is adequate (
Tx of Pipkin type 2 (involve the weight bearing surface)
Same recommendations as type 1 for non-op except only anatomic reduction as seen on CT and repeat radiographs can be accepted. ORIF with countersunk mini-frag implants or headless screws through anterior approach (smith-peterson)
Pauwel Classification of Femoral neck fractures
Based on angle of fx from horizontal: type one is less than thirty degrees, type two is from thirty to seventy degrees, type three is greater than seventy degrees. Increasing shear forces with increasing angle lead to more fracture instability
Seinsheimer classification of subtroch fxs
Type One: nondisplaced/less than two mm displacement
Type Two A: Two part transverse fx
Type Two B: two part spiral with lesser attached to prox frag; Type Two C: two part spiral with lesser attached to distal frag (reverse obliquity fx)
Type Three A: Three part spiral fx with less being part of third frag; Three B: three part spiral fx with third part a butterfly frag
Type four: comminuted fx of four or more parts
Type five: Subtroch - intertroch fx, any subtroch fx w/ extension through the greater troch
Fielding classification of subtroch fxs
Type one: at the level of the lesser troch; type two: less than two and a half cm below the lesser; type three: two and a half to five cm below the lesser
Contraindications to retrograde IM nailing femur fxs
Restricted ROM knee less than sixty degrees, patella baja
Classification system used for periprosthetic hip fxs (THA)
Vancouver Classification system
Vancouver Classification system and treatment
Type A: fx at the troch region; ORIF in displaced fxs
Type B1: fx around the stem or just below with a well fixed stem; ORIF with cerclage cables and locking plate
B2: fx around stem or just below it with stem loosening but good prox bone stock; revision to longer stem
B3: fx around the stem or just below it with stem loosening and poor bone quality or comminution; femoral component revision or prox femoral replacement
Type C: fx well below prosthesis; ORIF with plate
Distal Femur Periprosthetic TKA fx classification
Neer and Associates; also DiGioia and Rubash
