Aim
Tumour removal to gain local control & minimize recurrence while maintaining functional limb
Margins
1. Intralesional
Within lesion
- macroscopic tumour remains
2. Marginal
Within reactive zone
- microscopic tumour remains
3. Wide
Intra-compartment and outside of reactive zone
- tumour & cuff of normal tissue
Beyond reactive zone
- > 7cm level on Te99 scan
- > 5cm level on MRI
- may leave skip lesions behind
- hence MRI
- remove biopsy site
- may mean amputation
4. Radical
Extra-compartmental
- removal of all compartments that contain tumour
Amputation is not necessarily Radical
- radical resection possible with limb salvage
Exceptions
Skin & subcutaneous tissue
- wide margin is < 5 cm
- radical margin is > 5 cm
Extracompartmental lesions
- can't have radical exision of extracompartmental lesions
- no longidudinal barriers to extracompartmental spaces
Two compartments
- both compartments must be removed to achieve radical resection
- sometimes only practical way to achieve this is amputation
Contamination
- when lesion entered, wound contaminated
- if exposed tissues not removed, margin is intracapsular
Surgery & Recurrence rate
| IA | IB | IIA | IIB | |
| Intralesional | 90% | 90% | 100% | 100% |
| Marginal | 70% | 70% | 90% | 90% |
| Wide | 10% | 30% | 50% | 70% |
| Radical | 0% | 0% | 10% | 20% |
Limb Salvage
About 80 - 85% patients with OS, Ewing's, CS amenable to limb salvage
Principles
- must have same survival rates
- must not delay adjuvant treatment
- reconstruction should be enduring with minimal complications
- function should approach that achieved by amputation
Contraindications
PIN LEG
- pathological fracture
- infection
- NV bundle involvement
- LLD > 8 cm
- extensive muscle loss
- Good v poor biopsy
Absolute
1. Can't obtain wide margins
2. Major NV involvement
- vessel grafts are possible
- nerve remains at risk
3. Infection
Relative
1. Pathological fracture
- hematoma spreads tumour beyond accurately defined limits
- may necessitate amputate
2. Inappropriate previous biopsy
- contamination of other compartment
3. Significant skeletal immaturity
- predicted LLD > 8cm
- adjustable / growing joint replacements availiable
4. Extensive muscle involvement
- leave leg non functional
5. Medically unfit
Technique
Radical or wide resection
- extra-articular resection is preferred if a tumour is adjacent to or involves a joint
- prophylactic antibiotics
- no tourniquet if possible
- no eschmarc
- biopsy site excised
- tumour &/or pseudocapsule not visualised during procedure.
- distant flaps should not be developed until the tumour has been removed
- all dead space should be eliminated, & haematoma formation should be prevented
- surgical wound marked with clips for later radiatherapy
- motor reconstruction by regional muscle transfer
- adequate soft tissue cover by flap to avoid skin necrosis
Reconstruction Options
Arthrodesis
Autograft (remove and irradiate)
Allograft arthrodesis
Allograft arthroplasty
Modular Endoprosthesis
Modular Endoprosthesis
Advantage
- early weight bear and rehabilitation
- lower infection rates than allograft
- no risk of non union like allograft
Types
- rotating hinge
- expandable if final LLD > 2cm
- modular
Contraindications
- < 8 years old
Complications
Early complications
- wound infection
- skin necrosis
- DVT
- neuropraxia
- instability
Late complications
- prosthesis breakage
- LLD
- lysis
- instability
- late infection
Expandable Prostheses
Lengthen 2cm every 18 months
- surgical procedure
- excise fibrous tissue to prevent joint stiffness and protect NV bundle
Average lengthening 9 cm
50% complication rate
Massive Allograft
Advantage
- biological reconstruction
Disadvantage
- incorporation is a slow and incomplete process
- 20% will fail within 5 years
Indications
- patient < 20 years old
Complications
- infection 11% (sometimes only salvageable by amputation)
- fracture 16% (up to 3 years later)
- joint instability
- non union (increased by chemo/DXRT)
- OA (15% at 10 years with osteochondral allograft)
Results
Intercalary > osteochondral
Intercalary
- 80% good results
- 30% non union at one osteosynthesis site requiring intervention
Osteochondral
- 73% good results
Allograft - prosthetic
- 77% good results
Rotationplasty
Concept
- creates a functional BKA
- superior to AKA
Advantage
- low complication rate
- very functional
Disadvantage
- high rate cosmetic dissatisfaction
- patients should meet others with same procedure
Indication
- young child in whom endoprosthesis has high rate failure
- wide resection about knee
- sciatic nerve preserved
Technique
- tibia rotated 180o
- fused to femur
Complications
- post operative vascular occlusion
- tibio-femoral pseudoarthrosis
Results
- patients can play sports
Limb lengthening
Usually very large osseous defects
- difficult
- associated with significant complications
- better suited as adjuvant to other procedures or for smaller defects
Vascularised fibula graft
Advantage over allografts
- more rapid incorporation
- stronger initial construct secondary to graft hypertrophy
Disadvantage
- increased surgical time
- surgical site morbidity
- size limitations
- stress fractures
Amputation v Limb Salvage
|
|
Limb Sparing |
Amputation |
|
Local Recurrence |
5 - 10% |
5% |
|
Survival |
70% |
70% |
|
Functional Outcome |
Good |
Good |
|
Initial Cost |
High |
Low |
|
Long term cost |
|
|
Outcome
- limb salvage often functionally better
- complication rate and incidence multiple surgery higher