Oncological Margins | Enneking Staging | Reconstruction Options | Functional Outcomes
SURGICAL MARGIN TYPES (ENNEKING)
Critical Must-Knows
- Wide margin = minimum 2cm bone, cuff of normal tissue (fascia/muscle) for sarcoma
- Enneking staging: Stage I = low grade, II = high grade, III = metastatic
- Endoprosthesis = gold standard for periarticular reconstruction after tumour resection
- Growing prostheses essential in paediatrics to address limb length inequality
- Rotationplasty = biological alternative providing excellent function for distal femur tumours
Clinical Pearls
- "Local recurrence with intralesional/marginal margins approaches 50-100% for high-grade sarcoma
- "Skip metastases occur in 1-5% - whole bone MRI essential before resection
- "Allograft-prosthetic composite combines biological fixation with prosthetic joint
- "Infection rate 10-15% for endoprostheses - higher than primary arthroplasty
Clinical Imaging
Imaging Gallery
Critical Limb Salvage Exam Points
Surgical Margins
Wide margin is minimum for sarcoma. Intralesional = curettage through tumour (contamination). Marginal = through reactive zone (microscopic disease). Wide = through normal tissue cuff (acceptable). Radical = entire compartment (rarely needed). Local recurrence correlates directly with margin adequacy.
Enneking Staging
Stage determines prognosis and treatment. Stage I = low grade (A intra, B extracompartmental). Stage II = high grade (A intra, B extracompartmental). Stage III = any grade with metastases. Surgical margins and adjuvant therapy guided by staging. Know benign staging too (1-3 latent to aggressive).
Reconstruction Options
Endoprosthesis is workhorse for periarticular reconstruction. Allograft provides biological stock but high complication rates. Autograft (vascularized fibula) for intercalary defects. Allograft-prosthetic composite combines benefits. Rotationplasty excellent function in young patients with distal femur tumours.
Complications
Infection 10-15% - higher than primary arthroplasty due to large dead space, adjuvant therapy effects. Aseptic loosening 5-10% at 10 years. Periprosthetic fracture 5-7%. Soft tissue failure (extensor mechanism, dislocation). Know Henderson classification for failure modes.
Reconstruction Option Selection Guide
| Clinical Scenario | Preferred Reconstruction | Alternative | Key Considerations |
|---|---|---|---|
| Distal femur osteosarcoma in adult | Modular endoprosthesis | Allograft-prosthetic composite | Most common tumour site, reliable outcomes |
| Proximal tibia tumour in adolescent | Extendible endoprosthesis | Rotationplasty | Must address growth potential and extensor mechanism |
| Diaphyseal femur tumour (intercalary) | Intercalary prosthesis or vascularized fibula | Allograft with plate | Preserve joints if possible, biological healing better |
| Distal femur in young child (under 8) | Rotationplasty | Expandable prosthesis | Multiple lengthening procedures vs single rotationplasty |
| Pelvis tumour (periacetabular) | Custom hemipelvic prosthesis | Flail hip (excision only) | High complication rate, consider function vs survival |
| Failed limb salvage with infection | Amputation | Two-stage revision if bone stock allows | Patient safety paramount, functional amputation better than non-functional salvage |
MARGIN - SMARGIN - Surgical Margin Principles
| M | Measure preoperatively MRI for tumour extent, CT for cortical involvement |
| A | Avoid reactive zone Marginal margin goes through reactive zone - inadequate |
| R | Radical rarely needed Whole compartment excision now uncommon |
| G | Goal is wide margin 2cm bone, cuff of normal tissue minimum |
| I | Intralesional is contamination Curettage spreads tumour - only for benign lesions |
| N | Neurovascular bundle Tumour encasement may preclude limb salvage |
| M | Measure preoperatively MRI for tumour extent, CT for cortical involvement | R | Radical rarely needed Whole compartment excision now uncommon | I | Intralesional is contamination Curettage spreads tumour - only for benign lesions |
| A | Avoid reactive zone Marginal margin goes through reactive zone - inadequate | G | Goal is wide margin 2cm bone, cuff of normal tissue minimum | N | Neurovascular bundle Tumour encasement may preclude limb salvage |
Hook:The MARGIN you achieve determines local recurrence and survival
SALVAGE - LSALVAGE - Limb Salvage Prerequisites
| S | Staging complete Local imaging plus chest CT for metastases |
| A | Adequate margin achievable Can achieve wide margin without neurovascular sacrifice |
| L | Limb function preserved Functional outcome must exceed amputation |
| V | Vascular supply intact Major vessel reconstruction possible if needed |
| A | Adjuvant therapy planned Neoadjuvant chemo for osteosarcoma, radiation for soft tissue |
| G | Growth potential addressed Growing prosthesis or rotationplasty in children |
| E | Expectations realistic Patient understands risks, complications, functional outcomes |
| S | Staging complete Local imaging plus chest CT for metastases | V | Vascular supply intact Major vessel reconstruction possible if needed | E | Expectations realistic Patient understands risks, complications, functional outcomes |
| A | Adequate margin achievable Can achieve wide margin without neurovascular sacrifice | A | Adjuvant therapy planned Neoadjuvant chemo for osteosarcoma, radiation for soft tissue | ||
| L | Limb function preserved Functional outcome must exceed amputation | G | Growth potential addressed Growing prosthesis or rotationplasty in children |
Hook:Check all SALVAGE criteria before proceeding - if any missing, consider amputation
ENDO - EENDO - Endoprosthesis Complications
| E | Extensor mechanism failure Proximal tibia - patellar tendon reattachment critical |
| N | Neurovascular injury Peroneal nerve at risk in proximal tibia resection |
| D | Deep infection 10-15% rate, two-stage revision or amputation |
| O | Osseous loosening Aseptic loosening 5-10% at 10 years |
| E | Extensor mechanism failure Proximal tibia - patellar tendon reattachment critical | D | Deep infection 10-15% rate, two-stage revision or amputation |
| N | Neurovascular injury Peroneal nerve at risk in proximal tibia resection | O | Osseous loosening Aseptic loosening 5-10% at 10 years |
Hook:ENDO complications are common - counsel patients about 30% reoperation rate at 10 years
Overview and Epidemiology
Definition
Limb salvage surgery is the surgical resection of a malignant bone or soft tissue tumour with reconstruction of the resultant defect, preserving a functional limb. The fundamental principle is achieving oncologically adequate surgical margins while maintaining limb function superior to amputation.
Evolution of Limb Salvage
Historically, amputation was the standard treatment for extremity sarcomas. The development of effective chemotherapy in the 1970s-80s, combined with advances in imaging (MRI) and reconstructive techniques (modular endoprostheses), revolutionized treatment. Limb salvage is now performed in 85-90% of bone sarcoma patients, with survival rates equivalent to amputation when adequate margins are achieved.
Epidemiology
Primary Bone Sarcomas:
- Osteosarcoma: Most common primary bone malignancy, peak incidence 10-25 years
- Ewing sarcoma: Second most common, peak 5-15 years
- Chondrosarcoma: Third most common, peak 40-60 years
- Combined incidence: 8-10 per million population annually
Common Sites Requiring Limb Salvage:
- Distal femur (35-40% of osteosarcoma)
- Proximal tibia (15-20%)
- Proximal humerus (10-15%)
- Proximal femur (10%)
Survival Equivalence
Limb salvage provides equivalent survival to amputation when adequate surgical margins are achieved. Multiple studies including the landmark Rougraff et al. series demonstrate no difference in overall survival or metastasis-free survival between limb salvage and amputation. The decision is therefore based on achieving adequate margins and functional outcome.
Indications for Limb Salvage
Absolute Requirements:
- Adequate surgical margin achievable (wide or radical)
- Reconstruction technically feasible
- Preserved or reconstructible neurovascular structures
- Expected function superior to amputation
Relative Contraindications:
- Tumour encasing major neurovascular bundle
- Pathological fracture with haematoma contamination
- Extensive soft tissue extension precluding reconstruction
- Skip metastases (may still salvage if all resectable)
- Patient factors (age, comorbidities, expectations)
Pathophysiology and Tumour Biology
Tumour Growth and Spread
Understanding tumour behaviour is essential for surgical planning. Bone sarcomas exhibit characteristic patterns that inform margin requirements.
Local Extension:
- Intramedullary spread: Osteosarcoma extends along medullary canal - MRI essential
- Cortical breakthrough: Creates reactive zone and soft tissue mass
- Skip metastases: Discontinuous intramedullary lesions in 1-5% of osteosarcoma
- Joint involvement: Rare but occurs through cruciate ligament insertion, direct extension
Reactive Zone: The reactive zone surrounds the tumour pseudocapsule. It contains:
- Compressed normal tissue
- Inflammatory cells
- Oedematous tissue
- Microscopic tumour extension
Marginal margins go through the reactive zone and leave microscopic disease in 40-50% of cases for high-grade sarcoma. This results in local recurrence rates of 50-100%. Wide margin through normal tissue is the minimum acceptable standard.
Chemotherapy Effects
Neoadjuvant Chemotherapy for Osteosarcoma:
- Standard of care - improves survival from 20% to 60-70%
- Reduces tumour size, facilitates limb salvage
- Creates necrosis - assessed at resection (Huvos grading)
- Good response (greater than 90% necrosis): Better prognosis
- Poor response: Consider adjuvant modification
Histological Response (Huvos Grading):
| Grade | Necrosis | Description | Prognosis |
|---|---|---|---|
| I | 0-50% | Little effect | Poor |
| II | 51-89% | Partial response | Intermediate |
| III | 90-99% | Good response | Good |
| IV | 100% | Complete response | Excellent |
Wound Healing Considerations
Tumour surgery creates unique wound healing challenges:
- Large dead space after resection
- Chemotherapy impairs healing and immunity
- Radiotherapy (soft tissue sarcoma) causes fibrosis
- Metalwork and allografts are foreign bodies
- Higher infection risk than routine arthroplasty
Classification and Staging
Enneking Surgical Staging System
The Enneking staging system is the most widely used classification for musculoskeletal tumours, guiding treatment and prognosis.
Enneking Staging for Malignant Tumours
| Stage | Grade | Site | Metastases | Treatment Approach |
|---|---|---|---|---|
| IA | Low (G1) | Intracompartmental (T1) | None (M0) | Wide excision, consider adjuvants |
| IB | Low (G1) | Extracompartmental (T2) | None (M0) | Wide excision, margins critical |
| IIA | High (G2) | Intracompartmental (T1) | None (M0) | Neoadjuvant chemo, wide excision |
| IIB | High (G2) | Extracompartmental (T2) | None (M0) | Neoadjuvant chemo, wide excision |
| III | Any grade | Any site | Present (M1) | Palliative or aggressive if isolated mets |
Compartmental Definition:
- Intracompartmental (T1): Confined within anatomical compartment (bone cortex intact)
- Extracompartmental (T2): Extends beyond compartment (cortical breach, soft tissue extension)
Know the Benign Staging Too
Enneking Benign Tumour Staging:
- Stage 1 (Latent): Static, asymptomatic (e.g., fibrous cortical defect)
- Stage 2 (Active): Symptomatic, growing (e.g., aneurysmal bone cyst)
- Stage 3 (Aggressive): Locally destructive (e.g., giant cell tumour)
Stage 3 benign may require margins similar to low-grade malignancy.
Clinical Presentation and Assessment
Presentation Patterns
Bone Sarcomas:
- Pain: Progressive, worse at night, not relieved by rest
- Swelling: Palpable mass in 50%
- Pathological fracture: 5-10% present with fracture
- Duration: Weeks to months
Red Flags for Malignancy:
- Night pain
- Progressive pain not responsive to simple analgesia
- Mass increasing in size
- Constitutional symptoms (weight loss, fatigue)
- Age-size mismatch (large lesion in young patient)
Do not attribute bone pain in a young person to "growing pains" or sports injury without appropriate investigation. Delayed diagnosis of osteosarcoma remains common - average delay 3-4 months from symptom onset.
Clinical Examination
Inspection:
- Mass location, size, skin changes
- Muscle wasting
- Limb length discrepancy
- Angular deformity
Palpation:
- Mass characteristics: Size, consistency, mobility, tenderness
- Relation to underlying bone
- Neurovascular status distally
Special Assessments:
- Joint range of motion (adjacent joints)
- Neurovascular examination (tumour may compress/invade)
- Lymph node examination (unusual for bone sarcoma but check)
Investigations
Investigation Protocol for Limb Salvage Planning
Initial assessment:
- AP and lateral of affected bone
- Assess lesion location, size, matrix
- Cortical involvement, periosteal reaction
- Pathological fracture assessment
Classic Features:
- Osteosarcoma: Sunburst periosteal reaction, Codman triangle
- Ewing: Permeative "moth-eaten" destruction, onion-skin periosteal reaction
- Chondrosarcoma: Rings-and-arcs calcification, endosteal scalloping
Whole bone with contrast:
- T1, T2, STIR sequences
- Gadolinium enhancement for soft tissue extent
- Measure intramedullary extent for margin planning
- Identify skip metastases (1-5%)
- Assess joint involvement, neurovascular proximity
Key Measurements:
- Distance from tumour to joint line
- Intramedullary extent (for bone cut level)
- Soft tissue mass dimensions
- Proximity to neurovascular bundle
Complementary to MRI:
- Cortical detail and matrix characterization
- Staging CT chest (essential)
- CT-guided biopsy if required
- 3D reconstruction for complex anatomy (pelvis)
Whole body assessment:
- Bone scan: Skeletal metastases
- PET-CT: Increasingly used for staging and response assessment
- PET may identify occult metastases
Biopsy principles:
- Core needle preferred over open (less contamination)
- Biopsy track excised with specimen
- Longitudinal approach, not transverse
- Experienced pathologist essential
- Frozen section at surgery to confirm diagnosis and margins
Biopsy Placement
The biopsy track is contaminated with tumour cells. Place the biopsy in line with the planned surgical incision so the track can be excised en bloc. Incorrectly placed biopsy may compromise limb salvage or require wider excision. In complex cases, perform biopsy at the treating centre.
Imaging Gallery
Management Principles
Preoperative Planning
Margin Determination:
- Review MRI with radiologist
- Measure intramedullary extent on MRI
- Add 2cm minimum to planned bone cut level
- Plan soft tissue cuff based on fascial planes
- Assess neurovascular involvement
Reconstruction Selection Factors:
- Patient age and growth potential
- Tumour location and resection extent
- Expected functional demands
- Available bone stock
- Soft tissue coverage
- Surgeon experience and resources
Prosthesis Planning:
- Custom vs modular prosthesis
- Sizing from imaging measurements
- Stem length and fixation type
- Joint constraint requirements
Bone Cut Level
Plan bone cut 2cm proximal to MRI-defined tumour extent. Add the distance from tumour edge to joint line to determine whether joint can be preserved (intercalary resection) or must be resected (articular resection). Joint preservation improves function when oncologically safe.
Surgical Technique - Reconstruction Options
Modular Endoprosthetic Reconstruction
Indications:
- Periarticular tumours (most common reconstruction)
- Distal femur, proximal tibia, proximal femur, proximal humerus
- Immediate stability and early mobilization required
Advantages:
- Immediate stability and weight bearing
- No donor site morbidity
- Predictable outcomes
- Modular systems allow customization
Disadvantages:
- Mechanical complications (loosening, breakage)
- Infection rate 10-15%
- Limited lifespan (70-80% survival at 10 years)
- Multiple revisions likely in young patients
Surgical Technique - Distal Femur
Steps:
- Incision: Extensile anterior or medial approach, excise biopsy track
- Tumour resection: Wide margin including cuff of normal muscle
- Bone cut: 2cm proximal to MRI-defined tumour extent
- Canal preparation: Ream to accept cemented or press-fit stem
- Prosthesis assembly: Modular system allows length adjustment
- Soft tissue reconstruction: Medial gastrocnemius flap for coverage
- Extensor mechanism: Suture quadriceps to prosthesis if needed
- Closure: Layered closure over drain
Technical Pearls:
- Avoid stripping soft tissue beyond resection margins
- Gastrocnemius flap essential for proximal tibia coverage
- Constrained hinge for most tumour prostheses
- Hydroxyapatite collars may improve soft tissue attachment
Complications
Henderson Classification of Endoprosthetic Failure
Type 1 - Soft Tissue Failure:
- 1A: Wound dehiscence, flap necrosis
- 1B: Aseptic instability (dislocation, tendon rupture)
- Most common: Extensor mechanism failure (proximal tibia)
Type 2 - Aseptic Loosening:
- Progressive loosening at bone-prosthesis interface
- 5-10% at 10 years
- Presents with pain, radiographic lucency
- May require stem revision
Type 3 - Structural Failure:
- 3A: Periprosthetic fracture
- 3B: Implant fracture (stem, body, hinge)
- Risk increases with time and activity level
Type 4 - Infection:
- Deep periprosthetic infection
- 10-15% overall (much higher than primary arthroplasty)
- Often requires two-stage revision or amputation
Type 5 - Tumour Progression:
- Local recurrence at resection margins
- Requires re-resection or amputation
Henderson Classification Summary
| Type | Category | Incidence | Management |
|---|---|---|---|
| Type 1A | Wound dehiscence/flap failure | 5-10% | Soft tissue coverage, flap reconstruction |
| Type 1B | Instability/tendon failure | 10-15% (prox tibia) | Constraint revision, tendon reconstruction |
| Type 2 | Aseptic loosening | 5-10% at 10 years | Stem revision |
| Type 3 | Structural failure | 5-7% | Fracture fixation or component exchange |
| Type 4 | Infection | 10-15% | Two-stage revision or amputation |
| Type 5 | Tumour progression | 5-10% | Re-resection or amputation |
Evidence Base
Limb Salvage vs Amputation Survival (Rougraff Landmark Series)
- 227 patients with non-metastatic high-grade distal femoral osteosarcoma across 26 institutions
- No significant difference in survival or disease-free interval between limb salvage, above-knee amputation, and hip disarticulation
- Local recurrence: 8/73 limb-salvage vs 9/115 amputation vs 0/39 disarticulation
- Limb-salvage patients required additional limb operations more often, but had higher MSTS functional scores
Endoprosthesis Long-term Survival (Jeys/Royal Orthopaedic Series)
- 661 endoprosthetic reconstructions with minimum 10-year follow-up (mean 15 years)
- Implant survival 75% at 10 years with mechanical failure as endpoint; 58% with failure from any cause
- 227 patients (34%) required revision: mechanical failure (116), infection (75), local recurrence (36)
- Limb salvage maintained in 84% at 20 years despite the high revision burden
Rotationplasty Functional Outcomes (Hillmann Gait Analysis)
- 43 patients after rotationplasty for femoral or tibial bone tumour, mean follow-up 6.7 years
- Good functional result: mean MSTS score 23.9/30 (approximately 80%)
- Gait analysis showed a near-normal walking pattern with only a slight limp and lateral trunk lean
- Younger age at operation correlated with better total functional score and walking ability
Paediatric Reconstruction & Growing Prostheses (Groundland Review)
- Endoprosthesis, massive allograft, allograft-prosthesis composite and expandable prostheses are all viable options in the growing child
- Expandable prostheses extend limb salvage even to patients far from skeletal maturity
- Reported high complication and revision burden across the paediatric literature, driven by infection, mechanical failure and loosening
- Authors stress the literature needs outcome reporting stratified by age, anatomical site and reconstruction type
Endoprosthetic Failure Modes (Henderson Classification)
- 2174 patients across five institutions; 534 endoprosthetic failures analysed
- Five failure modes defined: Type 1 soft-tissue, Type 2 aseptic loosening, Type 3 structural, Type 4 infection, Type 5 tumour progression
- Infection was the commonest failure mode in this series; aseptic loosening commonest in the pooled literature
- Failure mode and timing depend significantly on anatomical location - cumulative reporting is misleading
Lifetime Burden of First-Generation Endoprostheses (Grimer)
- 230 patients followed more than 25 years (mean 29.4 years) after endoprosthetic replacement
- Mean 2.7 further operations per patient; only 18% still had the original prosthesis
- Risk of amputation 16% at 30 years; limb salvage maintained in the majority
- Infection risk persisted at roughly 1% per year for the life of the implant (highest at the proximal tibia, 43%)
Surgical Staging of Musculoskeletal Sarcoma (Enneking System)
- Stratifies sarcomas by grade (G), anatomical compartment (T) and metastasis (M)
- Three stages: I low-grade, II high-grade, III any grade with metastases; subdivided A intracompartmental / B extracompartmental
- Defines the four operative margins: intralesional, marginal, wide and radical, relative to tumour and reactive zone
- Remains the foundational surgical staging framework for bone sarcoma decision-making
Clinical Decision Scenarios
Use these scenarios to practise clinical reasoning and management decisions
Distal Femur Osteosarcoma - Planning
"A 16-year-old male presents with a 3-month history of progressive right knee pain. X-rays show a destructive lesion in the distal femur with periosteal reaction. MRI confirms a 10cm lesion extending to within 4cm of the joint line with soft tissue mass but no joint involvement. Chest CT is clear. Biopsy confirms high-grade osteosarcoma."
Proximal Tibia Tumour in Child
"An 8-year-old girl has been diagnosed with osteosarcoma of the proximal tibia. She has completed neoadjuvant chemotherapy with good response. MRI shows the tumour 3cm from the joint with good response to chemotherapy. Chest CT is clear."
Infected Tumour Prosthesis
"A 25-year-old woman had a distal femoral replacement for osteosarcoma 3 years ago. She presents with a 6-week history of increasing knee pain, swelling, and a discharging sinus. Inflammatory markers are elevated. Aspiration grows Staphylococcus aureus."
Guidelines, Registries & Global Practice
Global Epidemiology
Primary bone sarcomas are rare worldwide, with osteosarcoma the commonest primary bone malignancy. According to PubMed, large registry analyses (SEER) historically described a bimodal age distribution, but contemporary US data (Kar et al., J Bone Oncol 2024) show the incidence is now unimodal, with a single consistent peak in the second decade of life and no reproducible second peak in older adults (DOI). In an Australian context, approximately 200 new bone sarcomas are diagnosed annually, with osteosarcoma accounting for roughly one-third; the distal femur remains the single commonest site requiring limb salvage globally.
| Metric | Figure | Source |
|---|---|---|
| Commonest primary bone malignancy | Osteosarcoma | SEER / global registries |
| Modal age distribution (osteosarcoma) | Unimodal, peak 2nd decade | Kar et al. 2024 |
| Commonest limb-salvage site | Distal femur | Multi-series |
| Limb salvage rate (bone sarcoma) | 85-90% | International series |
Guideline Comparison
International guidelines are highly concordant: centralised care in a specialist sarcoma centre, multidisciplinary team (MDT) decision-making, image-guided core biopsy with track excision, and limb salvage with wide margins whenever oncologically safe.
Guideline & Registry Comparison - Bone Sarcoma / Limb Salvage
| Body / Region | Key Position | Evidence Basis |
|---|---|---|
| ESMO-EURACAN-PaedCan (Europe) | Mandatory referral to a reference sarcoma centre before biopsy; MAP chemotherapy then wide excision for high-grade osteosarcoma | Clinical Practice Guideline (Strauss et al. 2021) |
| NICE / BSG (UK) | Diagnosis and surgery only in designated bone-cancer centres; whole-bone MRI and MDT before definitive surgery | National service specification, consensus |
| AOA / Australian Sarcoma Group (Australia) | Centralised metropolitan sarcoma services; telehealth and shared care for regional patients; PBS-subsidised MAP agents | Consensus / service model |
| AAOS / MSTS (USA) | Surgical staging (Enneking) and MSTS functional scoring as standard outcome metrics; endoprosthesis the workhorse reconstruction | Classification / consensus |
According to PubMed, the ESMO-EURACAN-GENTURIS-PaedCan bone sarcoma guideline (Strauss et al., Ann Oncol 2021) is the most comprehensive international standard, recommending referral to a reference centre before biopsy, neoadjuvant MAP chemotherapy for high-grade osteosarcoma, and wide surgical margins (DOI).
Registry & Access Considerations
The Australian Orthopaedic Association National Joint Replacement Registry (AOANJRR) primarily captures primary and revision arthroplasty; tumour endoprostheses are a distinct subset whose higher revision rates reflect salvage surgery in young patients facing life-threatening disease. Long-term implant data are therefore drawn mainly from high-volume sarcoma-centre series (e.g. the Royal Orthopaedic Hospital cohorts) rather than national arthroplasty registries.
Treatment protocols are globally aligned around neoadjuvant MAP chemotherapy and wide resection. In Australia the Pharmaceutical Benefits Scheme (PBS) subsidises methotrexate, doxorubicin and cisplatin, and prosthetic/limb services for amputees and rotationplasty patients are funded through state limb schemes and, for eligible patients, the National Disability Insurance Scheme (NDIS). Regional and remote patients face substantial travel burdens, which strengthens the case for single-procedure options such as rotationplasty where appropriate.
Differential Diagnosis
Key Differentials for an Aggressive Bone Lesion
| Diagnosis | Typical Age / Site | Discriminating Features | Implication for Salvage |
|---|---|---|---|
| Osteosarcoma | 2nd decade, metaphysis (distal femur) | Sunburst reaction, Codman triangle, raised ALP/LDH | Neoadjuvant MAP then wide resection + reconstruction |
| Ewing sarcoma | 5-15 years, diaphysis / flat bones | Permeative 'moth-eaten' lysis, onion-skin reaction, EWSR1 translocation | Chemo + surgery and/or radiotherapy (radiosensitive) |
| Chondrosarcoma | 40-60 years, pelvis / proximal femur | Rings-and-arcs calcification, endosteal scalloping; chemo/radio resistant | Wide surgical resection is the mainstay - margins critical |
| Giant cell tumour of bone | 20-40 years, epiphysis/metaphysis | Eccentric lytic lesion abutting subchondral bone, locally aggressive (Enneking benign stage 3) | Often curettage with adjuvant; salvage resection if extensive |
| Metastasis / myeloma | Over 40 years, axial / proximal long bones | Multiple lesions, known primary or paraprotein; commonest malignant bone lesion in adults | Biopsy and stage before any sarcoma-type resection |
| Osteomyelitis (Brodie abscess) | Any age, metaphysis | Periosteal reaction with lucent nidus, raised inflammatory markers, may mimic Ewing | Biopsy and culture before resection - not a tumour |
Limb Salvage Surgery Principles
Clinical summary
Enneking Staging
- •Stage I = Low grade (IA intracompartmental, IB extracompartmental)
- •Stage II = High grade (IIA intracompartmental, IIB extracompartmental)
- •Stage III = Any grade with metastases
- •Benign: 1 latent, 2 active, 3 aggressive
Surgical Margins
- •Intralesional = through tumour (contamination) - 90% recurrence
- •Marginal = through reactive zone - 50% microscopic disease
- •Wide = through normal tissue cuff - MINIMUM for sarcoma
- •Radical = entire compartment - rarely performed now
- •Wide margin: 2cm bone + cuff of normal tissue
Reconstruction Options
- •Endoprosthesis = workhorse for periarticular tumours (70-80% 10-yr survival)
- •Allograft = biological but high complication (nonunion 20%, fracture 20%)
- •APC = allograft-prosthesis composite (soft tissue attachment + joint)
- •Vascularized fibula = intercalary defects, paediatric
- •Growing prosthesis = paediatric, 15-20 lengthenings needed
- •Rotationplasty = excellent function, single procedure, cosmetic concerns
Key Numbers
- •Limb salvage rate: 85-90% for bone sarcoma
- •Survival equivalent to amputation if margins adequate
- •Endoprosthesis infection: 10-15% (vs 1-2% primary TKR)
- •10-year prosthesis survival: 70-80%
- •30% reoperation rate at 10 years (any cause)
- •Growing prosthesis complication rate: 50-70% during childhood
Henderson Classification
- •Type 1 = Soft tissue (1A wound, 1B instability/tendon)
- •Type 2 = Aseptic loosening
- •Type 3 = Structural (3A periprosthetic fracture, 3B implant fracture)
- •Type 4 = Infection
- •Type 5 = Tumour progression
Exam Day Essentials
- •Whole bone MRI essential - skip metastases in 1-5%
- •Biopsy track must be excised with specimen
- •MDT essential for all sarcomas
- •Neoadjuvant chemo standard for osteosarcoma
- •Rotationplasty underutilized - excellent function in children
- •Amputation is NOT failure if margins cannot be achieved
References
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Enneking WF, Spanier SS, Goodman MA. A system for the surgical staging of musculoskeletal sarcoma. Clin Orthop Relat Res. 1980;(153):106-120.
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Rougraff BT, Simon MA, Kneisl JS, et al. Limb salvage compared with amputation for osteosarcoma of the distal end of the femur. A long-term oncological, functional, and quality-of-life study. J Bone Joint Surg Am. 1994;76(5):649-656.
-
Jeys LM, Kulkarni A, Grimer RJ, et al. Endoprosthetic reconstruction for the treatment of musculoskeletal tumors of the appendicular skeleton and pelvis. J Bone Joint Surg Am. 2008;90(6):1265-1271.
-
Henderson ER, Groundland JS, Pala E, et al. Failure mode classification for tumor endoprostheses: retrospective review of five institutions and a literature review. J Bone Joint Surg Am. 2011;93(5):418-429.
-
Hillmann A, Rosenbaum D, Schröter J, et al. Electromyographic and gait analysis of forty-three patients after rotationplasty. J Bone Joint Surg Am. 2000;82(2):187-196.
-
Groundland JS, Binitie O. Reconstruction after tumor resection in the growing child. Orthop Clin North Am. 2016;47(1):265-281.
-
Strauss SJ, Frezza AM, Abecassis N, et al. Bone sarcomas: ESMO-EURACAN-GENTURIS-ERN PaedCan Clinical Practice Guideline for diagnosis, treatment and follow-up. Ann Oncol. 2021;32(12):1520-1536.
-
Kar E, Ammanamanchi A, Yousif M, et al. From bimodal to unimodal: the transformed incidence of osteosarcoma in the United States. J Bone Oncol. 2024;47:100613.
-
Grimer RJ, Aydin BK, Wafa H, et al. Very long-term outcomes after endoprosthetic replacement for malignant tumours of bone. Bone Joint J. 2016;98-B(6):857-864.
-
Mavrogenis AF, Ruggieri P, Mercuri M, et al. Allograft-prosthesis composite for reconstruction of proximal femur bone tumors. Orthopedics. 2010;33(12):888.
-
Benevenia J, Kirchner R, Patterson F, et al. Outcomes of a modular intercalary endoprosthesis as treatment for segmental defects of the femur, tibia, and humerus. Clin Orthop Relat Res. 2016;474(2):539-548.
-
Gosheger G, Gebert C, Ahrens H, et al. Endoprosthetic reconstruction in 250 patients with sarcoma. Clin Orthop Relat Res. 2006;450:164-171.