Limb Salvage Surgery Challenges in Bone Sarcomas

Courtesy: Alex Callan, MD, Assistant Professor, Orthopaedic Oncologist, UT SouthWestern Medical Centre, Dallas, Texas

 

Bone Sarcomas: Limb Salvage Surgery Challenges in Reconstruction and Rehabilitation

Objectives:
1. Describe bone sarcoma etiology and epidemiology
2. Understand treatment algorithms for bone Sarcomas in kids
3. List options for local control surgery (the 4 As!) : Amputation – Allograft – Arthroplasty – APC)
4. Understand rehabilitation challenges in limb salvage

SARCOMAS

• Origin: Greek “sarx” = flesh
• Sarcoma is a Cancer from a mesenchymal Cell line
• These are malignant tumors arising From bone, cartilage, muscle, Fat, nerve or vessels

MALIGNANT BONE TUMORS IN KIDS

Approximately 1200 newly diagnosed bone Sarcomas annually
-Osteosarcoma (most common)
-Ewing Sarcoma

Location

OSTEOSARCOMA
Common location is METAPHYSIS mainly in
-Distal Femur (40%)
– Proximal Tibia (20%)
-Proximal Humerus (10%)

EWING SARCOMA
Common location is diaphysis
Pelvis & scapula are favoured sites

OSTEOSARCOMA

• Metaphyseal or metadiaphyseal
• Locations : Distal femur, proximal tibia, proximal femur and humerus
• Codman’s triangle where new bone forms in response to periosteal elevation
• Sunburst` appearance when the periosteum
• Does not have enough time to lay down a new layer and instead the Sharpey’s fibres stretch Perpendicular to the periosteum
  TYPES
  Conventional Intramedullary Osteosarcoma
  Non-conventional
  — Parosteal Osteosarcoma
  – Periosteal Osteosarcoma
  – Telangectatic Osteosarcoma
  – High Grade Surface OS or Low Grade Intramedullary
  Small Cell Osteosarcoma
  Secondary Osteosarcoma

Conventional Osteosarcoma

– Osteoblastic osteosarcoma
– Chondroblastic osteosarcoma
– Fibroblastic osteosarcoma

Conventional Osteosarcoma
– Overall, if >90% necrosis
75% 5-year survival
70% 10-year survival
If Necrosis is less than 90%, worse survival

EWINGS SARCOMA

• Presenting complaints are Pain, fevers, swelling
• Age: 10-30s
• Radiographs: Sunburst appearance, Onion Skin appearance, Codman triangle
• Common location is diaphyseal or flat bone
• Diagnosis : Biopsy -> Small round blue Cells– FISH -> Translocation (t 11;22) ESW:FLI1
• Staging Work-up:
  Xrays entire Bone, MRI entire Bone, CXR
  Chest CT, PET Scan, Bone Marrow Biopsy
• PATHOLOGY
  Sheets of blue, round cells
  Large nuclei (blue)
  Scant cytoplasm (primitive)
  Glycogen +
  CD99 +
  No extracellular matrix

Treatment:

Diagnosis and Staging
– Biopsy
– MRI extremity, CT Chest, Bone Scan or PET Scan

Chemotherapy (Neoadjuvant) for 10-12 weeks
– Non Weight bearing Extremity to prevent fracture

Surgery (Radical Resection & Reconstruction)

Chemotherapy (Adjuvant)

Surveillance

Secondary goals

• Provide the best reconstruction to restore Function to the limb
• This is complicated with tumors located in Close proximity to joints, muscles and Neurovascular structures.
• To make matters worse many patients are still growing kids.

Limb Salvage Surgery is performed if:

1. Adequate margin for resection of tumor can be obtained with low risk ( 8 cm Extensive muscle or soft-tissue involvement
2. Poor response to preoperative chemotherapy

The various modalities for limb reconstruction used are:

Arthrodesis

Mobile joint reconstruction
– Autoclaved tumor bone
– Allograft bone including osteoarticular allograft
– Bone transfer (ulna and fibula to reconstruct radius and tibia respectively), Huntington’s procedure
– Endoprosthetic reconstruction
–Allograft end prosthetic reconstruction
– Custom-made prosthesis
– Rotationplasty

Amputation

• Above Knee Amputation (AKA)
• Hip Disarticulation
• External Hemipelvectomy

Rotationplasty

Limb-Salvage Treatment versus Amputation for Osteosarcoma Of the Distal End of the Femur:

Challenges with MEGA joint replacement

• Surgically removal all soft tissue Attachments (muscle, tendon, ligaments)
• Attempt to re-attach to metal implant or Cadaver bone
• Quad weakness, extensor lag, hip girdle Dysfunction, cuff atrophy
• Nerve palsies
• Balance between Healing and Motion

Complex, Personalized Rehabilitation Based on Reconstruction Technique

May Need Prolonged Joint Immobilization to allow healing

Keep leg in a functional position
– Knee straight (avoid flexion contracture)
– Foot Plantigrade (avoid equinus contracture)

May need prolonged Non Weight Bearing status to allow healing to implant or allograft

Distal Femur Endoprosthesis:

• Cemented Implants allow for Immediate Weight Bearing
• Usually – Weight bearing as tolerated, no brace, no Restrictions
• If massive quadriceps resection, may use Hinged knee brace for ambulation Until quad strength returns

Proximal Tibia Endoprosthesis

• No Knee ROM! (KneeBrace locked in extension X 6 wks
• 3D walker boot
• Progressive ROM x 6 wks

Proximal Femur Endoprosthesis

Used in Anterior/Posterior Hip dislocation
Precautions :
No flexion over 80
No adduction
+/- Hip abduction Brace
+/- Knee lmmobilizer

Proximal Humerus/Total Humerus Endoprosthesis

Non weight bearing
Use Sling for 6-12 wks
No active motion to shoulder
Repair rotator cuff to metal

Limb Salvage Surgery : Distal femur COMPRESS Endoprosthesis

Need for Bony Ingrowth onto Implant
Work on Quad Strength and Knee ROM

Solutions for the Growing Child :

• Preserve Physis if possible
• Intercallary allograft
• Shut down contralateral physis
• Osteoarticular allograft
• Growing endoprosthesis
  – Minimally invasive expandable
• Non-invasive, magnetic expandable

– Girls reach skeletal maturity 12-14yr
– Boys reach skeletal maturity 14-16yr

Consider involved physis

Physeal Growth: Proximal Femur 3mm/yr, Distal femur 9mm/yr, Proximal tibia 6mm/yr, Distal tibia 5mm/yr

Reconstruction options

• Amputation (AKA or knee disarticulation)
• Osteoarticular allograft
• Arthroplasty: Proximal Tibial Endoprosthesis

Standard
– Minimally Invasive Expandable
– Magnetic, non-invasive expandable APC – allograft prosthetic complex

Proximal tibia allograft, hinged TKA

Management:

• Knee Immobilizer -> Cast
• Crutches or walker
• Non-Weight bearing
• Pain Control

Staging and Diagnosis

• X-ray entire Bone
• MRI Tibia with and without contrast
• Chest Xray
• CT Chest with contrast
• Whole Body Bone Scan
• Biopsy and cast placement

Summary:

• Bone Sarcomas (Osteosarcoma and Ewing Sarcoma are rare! 1200 new cases each year)
• Bone sarcoma treatment: Chemo – Surgery-Chemo
• List options for local control surgery (the 4 As!
  Amputation – Allograft – Arthroplasty – APC)
• Rehabilitation and recovery are challenging in limb salvage