DDH

DDH – Developmental dysplasia of hip
F：M = 5：1
intermediate risk：breech-born boys, not-at-risk girls
highest risk：positive family history, breech-born girls
most coomon：left hip, left occiput anterior position of most vertex-presenting newborn

Condition:
an unstable, subluxated or dislocated hip
malformed acetabulum

PE:
Barlow’s: dislocation
Ortolani’s: relocation
Frequency: QOD initially, then (1, 2, 3, 4 6, 9, 12)

MTOS – Fractures – ORIF for pubis symphysis diastasis

Ligamentous structure
．Sup and inf pubic ligament
．Arcuate ligament

Indication :
．Diastasis > 2.5 cm (Tile B or C)
．Pain relief and stability of anterior pelvic ring
．Tile B: intact posterior pelvic ligament
．Diastasis: associated sacrospinous and anterior sacroiliac ligament rupture

Contraindication
．Critically ill, unstable patient`
．Open fracture with contaminated wound
．Skin compromise
．Suprapubic pouch (catheter)

Pfannenstiel incision
．Slightly curved incision above pubic symphysis
．For OB/GYN surgery
．Bikini line
．Linea alba: longitudinal splitting
．Detach linea alba: if failed reduction

Fixation methods
．reconstruction plate, 2 hole each side
．4.5mm Screw direction: A – P

Complication
．Loss of fixation: physiological motion in pubic symphysis, inadequate posterior fixation
．Impotence: due to initial injury

bisphosphonate for ONFH

published in JBJS Br, Aug 09

Alendronate
有些被用來治療ONFH

progression to collapse in 4 years
80% in control group
30% in intervention group

diagnosis of ONFH
l Predisposing factor of failure of THR or resurfacing

Early stage: better outcome

Stage III (collapse)
l Statistically significant better clinical function compared with control group
l Pain, disability, walking time, standing time

humeral nailing

Humeral nail
l For diaphysis(P/3 – M/3), proximal humerus (SN)
l For pathological fracture

Design concept：
l Spiral blade：increased surface area for load distribution
Small hole for suture anchoring of rotator cuff
l Compression design
l Locking design
l Oblique design

Increased tip – screw hole distance
Avoid stress concentration induced peri-implant fracture

Right and left, antegrade or retrograde
End cap from tissue ingrowth into threads
Proximal end: 5 mm below tip of greater trochanter
Distal end: 2.5 cm above olecranon fossa

Entry point
Proximal: lateral edge of acromion
Cartilage跟bone的交界處

Autologus chondrocyte implantation = from JBJS Br

Autologous chondrocyte implantation

• Micro-fracture
• Fibrous cartilage: poor resistance to shear force

Chondrocyte

• unable to migrate due to surrounded matrix
• could not fill the defect

injury deep into subchondral bone

• Release of potential mesenchymal cell
• Generation of fibrous cartilage
  

debridement, drilling and fixation, abrasion chondroplasty, microfracture and the use of carbon fibre pads,

1994 Britberg

• Chondrocyte harvested during arthroscopy
• Culture in suitable medua
• 5M cells
• injection into defect area and cover with periosteal flap: hyaline cartilage
  

< 2 cm2 condral defect: microfracture & mosaicplasty
1 ~ 12 cm2: ACI ( autologous chondrocyte implantation)

Pre OP evaluation

• correction of malalignment : mechanical axis
• r/o cruciate ligament and meniscus injury
• evaluation of chondrocyte lesion: Arthroscopy or MRI

Technique of ACI

• Harvest: chondrocyte from no-load-bearing area, trochlear groove
• Culture: 4-6 weeks
• Preparation of recipient area: arthrotomy, debrident, exposure of normal cartilage, avoidance of bleeding into defect area (hematoma formation), avoidance in bone defect area ( > 6mm lesion)
• Implantation
• Periosteal flap (proximal tibia) or biomembrane
• Secured with fibrin glue
• Suture: impairment of surrounding tissue and blood supply

MTOS-Ch.18-Arthroplasty for ITF

ITF:

most patient: union uneventfully



Becautious

1. Pathological fx

2. Unstable or comminuted

3. Medical comorbidity

4. Severe osteopenia

5. Previous implant failure



must r/o infection nonunion in previous operation failure

1. ESR & CRP

2. Intra-OP culture or smear



Approach

1. W/O greater trochanter fracture: AL or PL approach

2. W/ greater trochanter fracutre: Trochanter osteotomy aproach



Issue 1: When to remove prosthesis

1. after surgical dislocation

• femoral shaft w/o implant is weak. and his/her hip joint is stiff. iatrogenic shaft may be occured during surgical dislocation if implant was removed


• 先切掉head? eliminate femoral shaft fracture?

Issue 2: choice of Cup

• cementless with screw sugmentation


• press-fit w/o screw fixation is not recommended

Issue 3: choice of stem

calcar replacing prosthesis

• restore length
• reduce lesser or greater tuberosity
• fixation with Wire or cable

Issue 4: preparation of femoral canal

• scleroting tract, callus, deformity: deflecting reamer or broacher → iatrogenic fracture or femora canal peforation
• high speed burr to open femoral canal, then prepare femoral canal with reamer and broacher

Issue 5: stem length in femur with previous implant fixation

• 6 cm distal to previous screw hole ( 2 fold diaphysis diameter)
• avoid stress riser from screw hole

Issue 6: cemented stem

• good choice for severe osteopenic patient
• large cement leakage: cause of late periprosthetic fracture
• Clean and curette extravasation of cement

Issue 7: greater trochanter fracture

• cable or multiple wires
• stable enough for early mobilization
• autogenous bone grafting is recommended (harvested from femoral head)
• avoid abductor muscle strengthening in first 6 weeks

2-hole VS 4-hole DHS in ITF

關於DHS
l Side plate: 2-hole & 4-hole，biomechanical study上顯示一樣的stability
l 有人報過70個case，用2-hole side plate without failure
l 受力：力量順著posteromedial cortex傳導下來，如果有large posteromedial fragment，則受力不順，兩種情況
1. screw cut-out
2. distal screw因為一個varus collapse的力量，延伸過來變成一個pull-out strength。最後造成screw-plate interface fatigue failure

以上：其實large posteromedial cortex

就代表是unstable ITF, DHS should not be used

老年人，建議使用4個洞

因為cortex比較薄，screw的working length較不夠

Nov 2005. Injury

Biomechanics: comparision

FNF:
Cannulated screw in inverted triangle pattern

FNF, Vertical type
1. locking plate
2. DCS
3. DHS
4. Three cannulated screw

Reverse oblique ITF:
w/o gap: no difference in DHS, DCS, IM nail
w/ gap: IM nail > DCS > DHS

distal humerus fx
Orthogonal plating > posterior biplating

calcaneus

surgical repair for calcaneal tuberosity fracture
1. skin (tenting, shoe problem)
2. intraarticular involvement
3. incompetant soleus-gastrocnemius complex

surgical technique


Intra-articular fracture classification
Essex-Lopresti
1. Joint depression fracture: inferior + posterior force
2. tongue fracture: inferior force
後面一大塊tilting