· disabling hip pain
· functional impairment
· significant arthritis on radiographs
Degenerative
· primary
· childhood
· SUFE
· CDH
· Perthes
· trauma
· fracture
· dislocation
· metabolic
· Paget’s
· AVN
Inflammatory
· RA
· ankylosing spondylitis
Other
· infective
· septic arthritis
· osteomyelitis
· tuberculosis
· old fusion or pseudarthrosis
· failed reconstruction
· tumour
· proximal femur
· acetabulum
· elderly
· thin
· relatively inactive
· low functional demands
· no major medical illnesses
· failed nonoperative treatments
· active sepsis
· hip joint
· remote
· neuropathic joint
· insufficiency of abductors
· massive bone loss
· past history of osteomyelitis
· medical condition that precludes anaesthesia or rehabilitation
· young patient
· high-demand activities
General
· general health
· mobility
· life expectancy
· fitness for anaesthetic
· cardiopulmonary
· urinary status
· eradicate UTI
· perform TURP before THR
· drugs
· cease NSAIDs and aspirin
Hip
· examine hip
· abductor strength
· leg length
· contractures
· examine other joints
· knee
· foot
· check peripheral vascular status
· check skin
· eliminate open lesions and sepsis
· eliminate other causes of pain
· spine
· trochanteric bursitis
· intra-abdominal problem
Education and advice
· informed consent
· autologous blood
· rehabilitation
· home modifications
Requirements
· AP pelvis and lateral of hip
· AP and lateral of proximal femoral shaft
Assessment
· acetabular bone defects
· femoral canal size
· other deformities
· templating
· choose prosthesis
· choose tentative sizes
· ensure equipment available
· personal preference
· common options are
· posterior (Southern)
· lateral (Hardinge)
· transtrochanteric (Charnley)
Cup
· define true floor
· may need to remove curtain osteophytes
· depth of reaming variable
· trade-off between medialisation and preservation of subchondral bone
Stem
· leave some cancellous bone
· shock absorber
· allows cement interdigitation
Stem
· anatomical anteversion
· in neutral or slight valgus
Cup
· anatomical anteversion
· completely covered by bone
· accept more vertical orientation
Preoperative
· cease NSAIDs
Intraoperative
· prepping and draping difficulties from contracture
· may require adductor tenotomy first
· must remove acetabular osteophytes before dislocation
· need to remove curtain osteophytes from fovea to expose true floor
· reaming sclerotic floor may be difficult
· must medialise cup to allow lateral coverage
Postoperative
· often large and heavy with difficulty mobilising
Preoperative
· cease NSAIDs
· perioperative IV hydrocortisone if steroid dependent
Intraoperative
· anaesthetic problems with mouth opening and neck involvement
· care with skin during prepping and manipulation because of fragility
· gentle dislocation with increased risk of fracture
· problems of acetabular protrusio
· gentle acetabular retraction and reaming to prevent damage or penetration
· careful femoral preparation to prevent perforation
Postoperative
· difficulty mobilising with multiple joint involvement
· increased risk of infection
Postoperative
· increased failure rate (40% at 10 yrs)
· due to cause of AVN
· alcohol
· corticosteroids
Intraoperative
· sharp reamers and broaches for hard bone
· excessive bleeding
· large bowed femoral shaft that requires large component, large distal occluder and multiple packages of cement
· problems of acetabular protrusio
Postoperative
· no increased heterotopic bone formation
· no increased loosening
Preoperative
· fused hip may exacerbate LBP or ipsilateral knee pain
· fused hip does not compromise THR on other side
· conversion should not be undertaken lightly
Intraoperative
· difficulty prepping and draping
· should perform trochanteric osteotomy
· may require adductor and psoas tenotomy
· identify sciatic nerve
· avoid excessive tension on nerve with lengthening
Preoperative
· ensure no infection
· no drainage
· no sequestrum on x-ray
· normal ESR and CRP
Intraoperative
· abandon procedure if infection identified
Preoperative
· do not embark lightly
· technically very difficult
· only perform if degenerative disease causing significant functional impairment
Intraoperative
· adductor tenotomy required
· sciatic nerve liable to injury
· approach
· stretching with leg lengthening
· may need to abandon if
· insufficient pelvic bone stock
· abductors insufficient
· acetabulum
· must identify true acetabulum
· may need bone graft for superior defect
· femur
· orientation difficult because of marked anteversion
· difficulty reaming because of canal narrowness and anterolateral bowing
· small components required
Preoperative
· if performed for infection, ensure no infection
· no drainage
· no sequestrum on x-ray
· normal ESR and CRP
· traction may pull proximal femur level with acetabulum
Intraoperative
· adductor tenotomy required
· sciatic nerve may be encased in scar
· significant soft tissue release required
· femur may have to be shortened to allow reduction
Postoperative
· do not expect restoration of ROM or leg legnth
· risk of recurrence of infection (if performed for infection)
Types
Primary
· Otto pelvis (arthokatadysis)
Secondary
· existing prosthesis
· septic arthritis
· central fracture-dislocation
· Paget’s disease
· inflammatory arthritis
· osteomalacia
Principles
· place hip centre in anatomic location to restore biomechanics
· use intact peripheral rim for component fixation
· reconstruct defects with bone graft
Preoperative
· define acetabular defect with appropriate imaging
Intraoperative
· sciatic nerve should be identified as closer to joint
· trochanteric osteotomy may be required for exposure
· dislocation may be very difficult
· first try removing portion of posterior acetabulum
· may have to ostoeomise neck in situ
· significant soft tissue release from femur needed
· do not ream medially or use centering hole
· remove cartilage and soft tissue with curette
· enlarge rim only with reamer
· use one or more techniques to prevent medial migration
· take care not to create peripheral defect
· use wire mesh in floor
· graft floor with morsellised bone or bone wafers
· cement metal ring to margins of acetabulum
· use large cup with flange
· 90% 10 year survival rate
· most common problem is loosening
· goal is incidence of < 1%
· decreased with
· prophylactic antibiotics
· ultra-clean air
· without prophylaxis
· DVT occurs in 40-70%
· fatal PE occurs in 2%
· most significant and common complication
· due to particle disease
· common (60%)but not usually problematic (1-5%)
· increased risk with
· previous HO
· hypertrophic arthritis
· ankylosing spondylitis
· prophylaxis wtih
· indocid
· low-dose radiation
· occurs in 2-3% of cases
Mechanism
· two positions
1. flexion, adduction and internal rotation
· causes posterior dislocation
· more common (80%)
· occurs when rising from low chair
2. extension, adduction and external rotation
· causes anterior dislocation
Predisposing factors
Preoperative
· prior hip surgery
· revision THR
Intraoperative
· approach
· posterior approach (affects cup orientation)
· head size
· no evidence
· theory - 22 mm head has higher dislocation rate because impinges earlier and stretches capsule less
· leg length inequality
· no evidence
· theory - short limb decreases abductor tension
· component orientation
· cup out of acetabular safe zone
· is 15+/-10o anteversion and 40+/-10o abduction (from horizontal)
· excessive femoral anteversion
Postoperative
· range of motion
· increased mobility (with capsular stretching and component levering)
Aetiology
1. compromised soft tissue envelope with muscle imbalance
· nonunion of trochanteric osteotomy
· effective shortening of limb
· neuromuscular disorders with abductor weakness
2. malposition of components
· acetabular retroversion
· posterior approach
3. impingement of components or bone
· cement
· osteophytes
4. extremes of position
· trauma
· confusion
Prevention
Imbalance
· preoperative planning with templating to maintain leg length and offset
· recreation of leg length equality with avoidance of effective shortening
· excessive deepening of femoral neck
· excessive bone resection from femoral neck
· varus position of femoral component
· avoidance of or careful reattachment of trochanteric osteotomy
Malposition
· careful patient positioning
· adequate exposure
· care with posterior approach
· careful anterior retraction of femur
· anterior capsule release to assist anterior femoral displacement
· repair of posterior structures
· removal of osteophytes from acetabulum to aid in orientation
· use of anatomical landmarks rather than cup holder only
· careful orientation with
· cup anteverted 10-15o
· cup inclined 45-55o from vertical
· stem in slight anteversion
· can assess degree of cup version on x-ray
· superimposition of wire in cup means neutral
· ellipse means version
· angling of tube until wires supermiposed indicates amount and direction of version
· orientation of liner lip into position of maximal benefit
· usually posterosuperior
· cementing of femoral component in same position as trial reduction
· inadvertent shortening with varus or distal migration
· removal of loose bodies from acetabulum
Impingement
· removal of osteophytes and cement
· removal of excess bone when acetabulum deepened
· osteotomy and lateralisation of trochanter when posteriorly displaced
· eg. CDH
· avoidance of excessively horizontal cup which impinges in flexion
· correct orientation of liner lip to prevent impingement
· assess on trial reduction
Extremes of position
· preoperative education
· abduction pillow
· knee immobiliser with confused patients
· postoperative education
Timing
Early
· within 6 weeks
· represents majority of dislocations
· usually due to malposition of hip before adequate
· muscle control
· soft tissue healing
· minimal chance of recurrence
Late
· after 6 weeks
· represents majority of recurrent dislocations
· usually due to increase in ROM and activity that manifests unrecognised
· impingement
· component malposition
· usually recurrent
· 40% require revision surgery
Treatment
Early
· reduction under analgesia and muscle relaxation or GA
Late
· first episode treated with reduction
· recurrence treated with abduction brace or cast
· 20o flexion, abduction and ER
· for 6 weeks
· repeated dislocations treated with revision
· procedure depends on cause
· impingement
· removal of osteophytes or cement
· effective shortening
· longer neck if modular
· revision of stem if not modular
· malposition
· augmentation of polyethylene lining
· revision of malpositioned component
· abductor insufficiency
· no obvious cause
· trochanteric osteotomy and advancement
· revision to bipolar component
· constrained socket design (if can accept increased loosening)
· failure or unreliable patients (noncompliant, alcoholic, drug abusers)
· removal of components
Extrapelvic nerves
Sciatic nerve
· incidence is
· 1% in primary THR
· 3% in revision THR
· 5% in CDH and other leg lengthening procedures
· mechanisms of injury
· direct injury during exposure
· injudicious retraction
· stretching during extremes of positioning of leg
· damage from reamers, diathermy
· damage from wires, sutures
· thermal damage from cement
· stretching with leg lengthening
· compression by haematoma, esp. if anticoagulated
· postoperative dislocation
· prevented by exposure of nerve with
· revision surgery
· external rotation deformity
· protrusio acetabulae
· CDH
· recovery
· majority of palsies are partial
· most recover significantly or completely (80%)
· main persistent symptom is causalgia (30%)
· prevention
· warn patient
· care during difficult cases
· treatment
· immediate exploration in complete lesion or painful lesion for obvious cause
· exploration after 6 weeks in incomplete lesion
· foot drop splint
Peroneal nerve
· peroneal branch of sciatic nerve may be damaged as above
· more vulnerable than tibial branch
· more fixed, more exposed and less connective tissue
· may occur postoperatively
· straps from abduction pillow
· pressure with external rotation of extremity
Femoral nerve
· mechanisms of injury
· stretching from manipulation and leg lengthening
· retractors over anteroinferior lip of acetabulum
· cement extrusion anteromedially
· transacetabular screws in anterior quadrants
· compression by haematoma
Intrapelvic neurovascular structures
· damage occurs with
· positioning of retractors
· screws to fix uncemented cup to acetabulum
· intrapelvic intrusion or removal of cement
Quadrants
· floor may be divided into quadrants by 2 lines
· line A from ASIS to posterior fovea
· line B perpendicular to linea A
· forms 4 quadrants
· anterosuperior
· anteroinferior
· posterosuperior
· posteroinferior
Screws
· screws may penetrate neurovascular structures
· may not be immediately appreciated
· significant intrapelvic bleeding may occur before diagnosis made
· should avoid certain quadrants with screws
1. PS and PI
· contain best bone stock
· relatively safe
· long screws may endanger superior and inferior gluteal neurovascular structures and sciatic nerve
2. AS and AI
· screws endanger external iliac (esp. AS) and obturator (esp. AI) neurovascular structures
· little protective interposition of soft tissue
· poor bone stock
3. pole of acetulum
· endangers obturator NV bundle
Cement
· damage may be due to
· thrombi from heat of polymerisation
· kinking or occlusion from bolus
· erosion with false aneurysm from spicule
· avulsion due to adhesions at removal
· should avoid cement intrusion into pelvis
· wire mesh cement restrictor with Charnley approach
· wire mesh in floor with acetabular defect
· care must be taken during intrapelvic cement removal
· required in revision for infection
· define vascular relationships with angiography, CT or MRI
· may require separate intrapelvic exposure
External iliac vessels
· injury occurs during all phases
· injury to EIA more common
· anatomy
· EIA is anterior division of bifurcation of common iliac artery at L5-S1 disc
· runs down medial border of psoas
· some psoas interposed between itself and intrapelvic surface of anterior column
· EIV accompanies artery
· mechanisms of injury
· positioning with preexisting atherosclerosis with thrombosis or plaque embolism
· retractors over anterior lip of acetabulum over rather than under protective psoas
· damage during reaming or drilling of anchoring holes (esp. to EIV)
· cement extrusion into pelvis with heat damage or direct compression
· laceration with transacetebular screws due to drill, depth gauge or screw in anterior quadrants
· delayed injury due to socket migration
· delayed injury from cement from spicules or vessel erosion
· tearing of vessels with removal of cement during revision
Femoral vessels
· most commonly injured
· anatomy
· CFA is continuation of EIA as passes under inguinal ligament
· passes anterior to hip joint capsule
· separated from it by psoas
· CFV is medial to artery
· mechanisms of injury (similar to above)
Obturator vessels
· anatomy
· artery, vein and nerve traverse lateral wall together
· separated from quadrilateral plate by obturator internus
· lie at superolateral aspect of obturator foramen
· exit pelvis via obturator canal
· mechanisms of injury
· laceration with screws in anterior inferior quadrant
· retractor under transverse acetabular ligament
Superior gluteal vessels
· anatomy
· SGA is branch of posterior division of internal iliac artery
· vein and nerve travel with artery
· close to posterior column as exit superior sciatic notch
· pass above piriformis
· mechanisms of injury
· laceration with screw near sciatic notch
Inferior gluteal and internal pudendal vessels
· anatomy
· terminal branches of anterior division of internal iliac artery
· exit pelvis between piriformis and coccygeus
· close to posterior column near ischial spine
· internal pudendal artery re-enters pelvis through lesser sciatic notch
· inferior gluteal vessels pass under piriformis
· mechanism of injury
· excessively long screws through posterior column
Treatment
1. intraoperative
· vascular surgeon
· retroperitoneal approach
· clamping of internal iliac vessels
2. postoperative
· angiography
· transcatheter embolisation
Intraoperative
· increased incidence with press-fit components
· depend on intimate apposition of bone and metal
· act like splitting wedge
· fractures may occur during
· dislocation
· reaming or broaching
· impaction of component
· removal of cement or ingrown components during revision
Prevention
· during dislocation
· adequate exposure
· only one person manipulating femur
· if difficulty, complete soft tissue release and removal of marginal acetabular osteophytes
· if stiff joint or intrapelvic protrusion, division of neck in situ and piecemeal removal of femoral head
· during femoral preparation
· preoperative templating of component size
· use of reamers before broaching to remove endosteal bone
· gentle broaching with pause if failing to advance
· sufficient broaching for easy prosthesis insertion
· during component insertion
· gentle impaction with pause if failing to advance
Treatment
· vertical split not beyond lesser trochanter
· protected weight bearing
· cerclage wire
· vertical split beyond lesser trochanter
· cerclage wires
· longer-stemmed femoral component
· perforation of shaft
· repeated preparation of medullary canal
· longer-stemmed femoral component to bypass defect
· plug lesion with wire or strut graft if cemented
· bone graft lesion if uncemented
· internal fixation
· cementless
· complete exposure with broach or component in place
· removal of implant and insertion of one size smaller
· application of cerclage wire
· cemented
· anatomic reduction of fracture held with bone holding forceps or cerclage wire to prevent extrusion of cement between fracture fragments
Postoperative
· occur due to
· bone damage at time of surgery (eccentric reaming, perforation, fracture)
· osteolysis
· trauma
Classification
· type I
· proximal to tip with no distal extension
· type II
· from proximal portion to distal to tip
· type III
· entirely distal to tip
Treatment
· type I
· treat conservatively if prosthesis intact
· revision with long-stemmed component with cerclage wires if prosthesis loosens once fracture heals
· type II
· usually treat as type I but assume loosening will occur
· can treat as type III if noncemented or predominantly distal
· type III
· traction or cast brace if can maintain reduction
· internal fixation with Ogden plate or long plate for most fractures
Problem
· ideal is to have equal leg lengths
· patient can tolerate up to 5 mm
· likely to be symptomatic if > 10 mm
· but should be last priority after
· pain relief
· stability
· mobility
· average discrepancy is 1 cm
· lengthening occurs because of
· correction of contracture
· correction of protrusio
· inadequate neck resection
· excessively long or valgus neck
· excessive lengthening may cause
· sciatic nerve palsy
· impaired abductor function with abductor lurch
· short-leg limp
· low back pain
· theoretical decreased prosthesis longevity
· disgruntled patient
Solution
Explanation
· warn patient of risk of discrepancy
· explain that
· minor differences of little consequence
· may need to sacrifice leg length equality for stability
Preoperative assessment
· measure leg length preoperatively
· distinguish true from apparent discrepancy
· assess patient’s perception of leg lengths
Preoperative planning
· perform AP pelvis with magnification marker
· measure leg length difference by distance from lesser tuberosity to ischium
· mark current centre of hip joint
· template socket and mark new centre of hip joint
· template stem and assess effect on leg length and offset
· choose prosthesis and level of resection to recreate leg length
Intraoperative
· check for pistoning at trial reduction
· place pin superior to acetabulum after exposure
· measure distance from pin to point on lateral proximal femur
· place leg in same position for subsequent measurements
· recreate leg length with any desired correction at trial reduction
Postoperative assessment
· assess leg length
· discuss discrepancy with patient
· reassure that perceived difference will often fade with time
· suggest shoe raise if discrepancy poorly tolerated
· consider revision if
· recurrent dislocation
· profound functional impairment
Haematoma
· problem is
· dehiscence
· wound infection
· prevented with
· cease NSAIDs and aspirin 1 week preop
· careful haemostasis
· drains
· careful monitoring of warfarin if used
· treated with
· prophylactic antibiotics
· drainage in theatre if excessive pain or dehiscence
· advantages of trochanteric osteotomy
· better exposure
· easier orientation of components
· improved abductor power with advancement
· disadvantages of trochanteric osteotomy
· increased operative trauma
· bursitis
· nonunion
· proximal migration of trochanter
· high incidence of nonunion (5%)
· nonunion causes problems
· weak abductors with Trendelenburg gait
· increased risk of dislocation
· pain from bursa over broken ends
· greater incidence if migration > 2 cm
· no ideal solution
· numerous proposed techniques
· chevron osteotomy
· trochanteric slide with continous abductor, bone and vastus
· different configurations of multiple wire reattachments
· cable-clamp system
· osteotomy usually reserved for
· traditional Charnley technique
· difficult revision
· femoral shortening where distal advancement required
· protrusio acetabulae
· CDH
· conversion of arthrodesis
· activity related anterior thigh pain
· occurs in 15% of patients
· usually does not interfere with activity
· much more common with noncemented compnents
· may be due to
· inadequate fixation of uncemented femoral component
· modulus mismatch with large rigid femoral component
· problems of
· UTI and haematogenous seeding of prosthesis
· postop retention
· prevented by
· screen for history of recurrent UTI or prostatism
· routine MSU
· delay surgery until UTI eliminated
· TURP before THR
· prophylactic gentamicin with history of recurrent UTI
· IDC on induction with history of hesitancy or retention and spinal or epidural anaesthetic
· low threshold for IDC insertion postop (unable to void after 8 hrs)
· prophylactic gentamicin with postoperative IDC insertion
· loosening
· infection
· wide exposure
· removal of all pseudocapsule
· exposure of entire proximal femur
· exposure of entire circumference of acetabulum
· trochanteric osteotomy often used to aid exposure
Acetabulum
· often removed intact with curved gouge
· may need to be split and removed in pieces
· cement removed piecemeal with curved gouges
Femur
· stem often easily removed
· problems with
· retained distal stem
· cement
Stem
· drill with high-speed drill
· insert extraction device
Cement
· light and irrigation device
· special osteotomes, chisels and grabbers
· cement split radially and then removed
· can use high-speed burr
· may require distal window
· unclear whether cemented or cementless prosthesis
Classification
Cavitatory (contained)
· loss of bone from acetabular cavity
· eg. protrusio
Segmental (uncontained)
· complete loss of bone in supporting rim
· may be
· peripheral or medial
· superior, inferior, anterior or posterior
· eg. CDH
Combined
· both segmental and cavitatory
Pelvic discontinuity
· fracture of anterior and posterior columns
General
Planning
· AP, lateral and Judet views
· may require CT scan, incl. 3-D reconstruction
· stereolithographic model very helpful
· paul is a very nice person, and a great **** as well
Templating
· choose appropriate size
· estimate location of centre of rotation
Cavitatory
· large defects filled with wafers of femoral head or allograft
· small and remaining defects filled with morsellised graft
· tightly impacted by using last sized reamer in reverse
· intact peripheral rim used for support
Segmental
Central
· managed as cavitatory defects
· floor may need to be reinforced with wire mesh
· may require protrusio ring if insufficient peripheral rim for support
Peripheral
· can be disregarded if
· small
· anterior
· superior or posterior rim
· graft fashioned from femoral head
· fixed with lag screws
· may need to be reinforced with reconstrction plate
· another option is to recreate defect with wire mesh
· posterosuperior rim
· need larger graft
· can use distal femur
Classification of defects
Intraluminal
· canal widened but cortex intact
· eg. osteolysis
Cortical
· isolated cortical defects
· eg. perforation
Circumferential
· complete defect
· calcar (< 3 cm)
· proximal femur (> 3 cm)
Structural allograft
Cortical strut allograft
· strut cerclage wired over cortical defect
Large fragment proximal femoral allograft
· proximal host femur split to good bone
· distal host femur reamed to determine diameter
· proximal femoral allograft then prepared
· matching step cuts made in host femur and allograft
· desired stem cemented into allograft
· allograft-stem inserted into distal host femur
· proximal host bone wrapped around allograft
· cortical strut grafts wrapped around junction
· held with cerclage wire
Morsellised allograft
Planning
· identify sites of femoral bone loss
Templating
· choose approximate component
· determine position of distal plug
· 2 cm distal to most distal lytic area
Exposure
· full exposure of proximal femur
· removal of prosthesis and all cement
· can leave distal plug if
· not infected
· more than 2 cm past planned plug location
Repair of defects
· reconstitute femoral tube
· with wire mesh and cerclage wire
· may need to use reconstruction plate proximally
· may prophylactically cerclage wire shaft if diaphysis flimsy
Packing
· allografts from frozen femoral heads
· morsellised in bone mill
· should not be slurry
· should not be washed
Distal occlusion
· threaded intramedullary plug inserted on guide rod
· if bone plug left, drilled and guide rod screwed in
Distal impaction
· impacters tested to see maximum depth of insertion before abutment on canal
· morsellised allograft inserted
· impactor and slap hammer slid over guide wire
· graft vigorously impacted to predetermined depth
· continued by introducing more chips and using progressively larger impacters
· stopped when level is 10 cm from tip of greater trochanter
Proximal impaction
· appropriate proximal impactor equivalent to selected stem used
· used to force chips against walls of canal
· then larger distal impactor used
· alternated until canal filled
· should be firm neocanal
Trial reduction
· guide rod withdrawn
· trial stem inserted
· depth of insertion marked
· guide wire reinserted
· proximal impactor driven in another 5 mm
· to allow room for centraliser and cement
Cementing
· low-viscosity cement used
· cement pressurised into graft
· stem inserted earlier than normal
Postoperative
· touch weight-bearing for 3 weeks
· then gradual increase over next 3 months
· higher complication rate
· infection
· dislocation
· intraoperative fracture
· early failure