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Functional Outcome Following Modular Endoprosthesis Reconstruction Surgery in

Primary Bone Tumor of the Lower Limb

by

DR SHARIL BIN ABDUL RAHIM M.D. (U.S.M.)

Dissertation Submitted In Partial Fulfillment Of The Requirement For The Degree Of Master Of Medicine

(ORTHOPAEDICS)

UNIVERSITI SAINS MALAYSIA SCHOOL OF MEDICAL SCIENCES

2008

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DISCLAIMER

I hereby certify that the work in this dissertation is my own except for the quotations and summaries which have been duly acknowledged.

Dated: 27th May 2008

Dr. Sharil Abdul Rahim PUM1370

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ACKNOWLEDGEMENT

My sincere thanks to my supervisor, Associate Professor Dr. Wan Faisham Nu'man and co-supervisor Professor Dr Zulmi Wan, Orthopaedics Oncology Reconstructive Unit (OORU) in Department of Orthopaedics , Hospital Universiti Sains Malaysia, Kubang Kerian for his support, guidance and invaluable advice in the preparation of this dissertation and throughout the completion of my study.

Also my special thanks and appreciation to Associate Professor Dr Mohd Imran Yusuf, Head of Department of Orthopaedic , HUSM, all consultants, lecturers, colleagues and all the staff at the Department of Orthopaedic, HUSM.

My sincere gratitude to Dato' Dr Suresh Chopra, Head of Department of Orthopaedic, Hospital Alor Star, his encouragement and being the role model for me. Also my sincere gratitude to all consultants, specialists, colleagues and all the staffs at the Department of Orthopaedic, Hospital Alor Star.

Special thanks to Dr Sarimah and Dr Kamarul lmran who had never failed to guide me on the statistical analysis ofthis_study.

For both of my parents, Abdul Rahim b Md Shariff and Wan Enshah bt Wan Abdullah, thank you so much for believing in me and praying for my success in the program.

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To my beloved wife, Dr Hanina Idris, thank you for the constant support, understanding and sacrifices and last but not least, to all my children, Nabilah Hanim, Nazril Hisham, Nairn Hafiz and Nureen Husna, far away in Sg.Petani, Kedah, forgive me for the valuable time loss seeing all of you growing up and without whom I could never completed my study.

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LIST OF ABBREVIATION

HUSM - Hospital Universiti Sains Malaysia MSTS - Musculoskeletal Tumor Society LSS -Limb Salvage Surgery

OS - Osteosarcoma GCT- Giant Cell Tumor

DF endo - Distal femur endoproosthesis PT endo - Proximal Tibia endoprosthesis ROM- Range of movement

ISOLS- International Symposium on Limb Salvage TESS - Toronto Extremity Salvage Score

GMRS - Global Modular Replacement System

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TABLE OF CONTENTS

Page

TITLE PAGE 1

DISCLAIMER 11

ACKNOWLEDGEMENT lll

LIST OF ABBREVATION v

TABLE OF CONTENTS Vl

APPENDICES Xl

LIST OF TABLES Xll

LIST OF FIGURES XlV

ABSTRACT XVl

ABSTRAK XVlll

CHAPTER 1: INTRODUCTION 1

CHAPTER 2: LITERATURE REVIEW 4

2.1 Overview of Bone Tumor 5

2.1.1 Biology Behavior of Tumor 5

2.1.2 Classification of Bone Tumor 8

2.1.3 Etioiogy of Bone Tumor 9

2.2 Evaluation 10

2.2.1 Clinical Presentation 10

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2.2.2 Physical Examination 10

2.2.3 Radiography 11

2.2.3.1 Plain Radiograph 11

2.2.3.2 C.T. Scan 11

2.2.3.3 M.R.I. 11

2.2.4 Biopsy 12

2.3 Staging of Bone Tumor 13

2.4 Overview Management of Bone Tumor 17

2.4.1 History 17

2.4.2 Role of Chemotherapy 18

2.4.3 Surgery 19

2.4.3.1 Amputation 19

2.4.3.2 L.S.S. 20

2.4.4 Overview L.S.S 21

2.4.4.1 Types of Resection 23

2.4.4.2 Osseous Reconstruction 26

2.4.4.2.1 Autograft 27

2.4.4.2.2 Allograft 28

2.4.4.2.3 Endoprosthesis 30

2.4.4.2.4 Alloprosthesis 40

2.5 Outcome of Surgery 41

2.5.1 LSS versus Amputation 42

2.6 Functional Evaluation of Reconstructive Procedures 43

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2.6.1 M.S.T.S system

2.6.2 Toronto extremity score

CHAPTER 3: OBJECTIVES 3.1 General Objectives 3.2 Specific Objectives

CHAPTER4:METHODOLOGY 4.1 Research Strategy

4.2 Subject Selection 4.3 Period Of Study 4.4 Place Of Study

4.5 Ethical Board Approval

4.6 Sampling Size And Sampling Procedure 4.7 Selection Criteria

4.7.1 Inclusion Criteria 4.7.2 Exclusion Criteria 4.8 Details of Methodology 4.9 Data Collections

4.9.1 Socio-demographic data 4.9.2 MSTS system data 4.9.3 Others data

43 49

51 52 52

53 54 54 54 54 55 55 57 57 57 58 59 59 59 61

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4.9.4 Wound Infection 61

CHAPTER5:RESULTS 64

5.1 Demographic characteristics 65

5.1.1 Age distribution of study population 66

5.1.2 Race Distribution of study population 67

5.1.3 Gender distribution of the study population 68

5.1.4 Distribution of bone tumors 69

5.1.5 Distribution of patients has lung metastasis in primary bone tumors 70 5.1.6 Distribution of patient undergone type of reconstruction 71 5.1.7 Distribution of endoprosthesis system used in study 72

5.2 Clinical Characteristics 73

5.2.1 ROM of knee in PT endoprosthesis and DF endoprosthesis 73

5.2.2 MSTS functional score 75

5.2.3 MSTS functional score of PT endoprosthesis 76

5.2.4 MSTS functional score ofDF endoprosthesis 77

5.2.5 Percentage of MSTS score for PT and DF endoprosthesis 78 5.2.6 Description of Pain in MSTS functional score 79 5.2.7 Description of Function in MSTS functional score 80 5.2.8 Description of Emotional in MSTS functional score 81 5.2.9 Description -of Support in MSTS functional score 82 5.2.10 Description of Walking in MSTS functional score 83 5.2.11 Description of Gait

in

MSTS functional score 84
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5.2.12 Infection ofEndoprosthesis surgery in HUSM 85 5.2.13 Rate Infection ofPT and DF endoprosthesis surgery HUSM 86

5.2.14 Infection with MSTS score 87

5.2.15 Revision surgery in Endoprosthesis surgery in HUSM 5.3 Case Illustration (Case Sample no.22)

5.3.1 Picture of the patient (case no 22) during assessment 5.3.2 Picture of the patient (case no 31) during assessment 5.3.3 Picture of the patient (case no 18) with an infection

CHAPTER 6: DISCUSSION

6.1 Socio-Demographic Characteristics 6.2 Clinical Characteristics

CHAPTER 7: CONCLUSION

CHAPTER 8: LIMITATION

CHAPTER 9: RECOMMENDATION

REFERENCES

88 91 91 93 94

95 96 98

103

105

108

109

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APPENDICES Page

Appendix A: References 109

Appendix B: Demographic data sheet 115

Appendix C: MSTS data form 116

Appendix D: Flow chart 117

Appendix E: Certificate of Ethical Approval

Appendix F: Consent form 118

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LIST OF TABLES

Table 2.1:

Table 2.2:

Table 2.3:

Table 2.4:

Table 2.5:

Table 2.6:

Table2.7:

Table 2.8:

Table 5.1:

Table 5.2

Classification of primary tumors of bone

Enneking System for the Surgical Staging of Malignant Bone and Soft Tissue Tumors

MSTS pain description MSTS function description MSTS emotional description MSTS support description MSTS walking description MSTS gait description

Demographic characteristic of the study Type of Bone Tumor for the 54 patients

Page

8

15

44 45 46 47 48 49 65 69 Table 5.3: Number of patients with has Lung Metastasis in Primary Bone Tumor 70 Table 5.4: System of prosthesis used in Endoprosthesis surgery 72 Table 5.5: Comparison of Flexion of knee joint between PT endoprosthesis and

DF endoprosthesis 73

Table 5.6 MSTS functional scores 7~

Table 5.7: Description of Pain in MSTS score 79

Table 5.8: Description of Function in MSTS score 80

Table 5.9: Description of Emotional in MSTS score 81

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Table 5.10: Description of Support in MSTS score 82

Table 5.11: Description of Walking in MSTS score 83

Table 5.12: Description of Gait in MSTS score 84

Table 5.13: Percentage of Infection in Endoprosthesis surgery in HUSM 85 Table 5.14: Nwnber of patient getting infection in PT endoprosthesis compare to

DF Endoprosthesis 86

Table 5.15: Revision of surgery with other factors. 89

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LIST OF FIGURES Page

Figure 2.1: Various excision types for soft-tissue and tumors sarcoma 25 Figure 2.2: Custom distal femoral prostheses used between 1982 and 2000 31 Figure2.3: Modular replacement system (Howmedica, Inc.). 32 Figure 5.1: Distribution of patients according to age 66

Figure 5.2 Race Distribution of study population 67

Figure 5.3 Gender distribution of the study population 68 Figure 5.4 Distribution patients according to bone tumors 69 Figure 5.5: Distribution of patients has lung metastasis in primary bone tumors. 70 Figure 5.6 Distribution of type of reconstruction in primary bone tumors 71

Figure 5. 7 Distribution endoprosthesis system 72

Figure 5.8: Distribution ROM of knee joint in endoprosthesis surgery 74 Figure 5.9 Distribution ofMSTS score in both PT and DF endoprosthesis 75 Figure 5.10 Distribution ofMSTS functional score in PT endoprothesis 76 Figure 5.11 Distribution ofMSTS functional score in DF endoprosthesis 77 Figure 5.12 Distribution of% ofMSTS score for PT and DF endoprosthesis 78 Figure 5.13: Distribution of Pain in PT and DF endoprosthesis 79 Figure 5.14: Distribution of Function in PT and DF endoprosthesis 80 Figure 5.15: Distribution of Emotional in PT and DF endoprosthesis 81 Figure 5.16: Distribution of Support in PT and DF endoprosthesis 82 Figure 5.17: Distribution of Walking in PT and DF endoprosthesis 83

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Figure 5.18: Distribution of Gait in PT and DF endoprosthesis 84 Figure 5.19: Percentage of Infection in Endoprosthesis surgery in HUSM 85 Figure 5.20: Distribution of Infection in PT and DF endoprosthesis 86 Figure 5.21: Distribution of patient had infection and the MSTS score 87 Figure 5.22: Rate of Revision Surgery following Endoprosthesis 88

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ABSTRACT

Introduction: Wide resection in Limb Salvage Surgery for primary bone tumors results in segmental osseous defect. The optimum method for reconstruction distal femur and proximal tibia remained controversial. Options include the use of autografts, allografts, custom-made megaprostheses and modular endoprostheses. Endoprosthesis allows early rehabilitation with a good long term functional outcome result. . The aim of this study is to evaluate the functional outcome of patient in modular endoprosthetic reconstructions surgery in the treatment of primary bone tumors of distal femur and proximal tibia of the lower limb, by using Musculoskeletal Tumor Society scoring system.

Methods: Fifty four consecutive patients with primary bone tumor of distal femur and proximal tibia were selected and reviewed to determine the functional outcome after wide resection endoprosthesis reconstruction surgery by using Musculoskeletal Tumor Society scoring system.

Results: There were 34 (63%) cases of distal femur and 20 (37%) cases of proximal tibia bone tumor. The Primary osteosarcoma are 33 (61.1%) and stage III GCT are 20 (37%).

The mean age is 26.6±10.61. There were 12 (22.2%) patients who had met~tasis to the lung. The mean MSTS score for both DF and PT endoprosthesis was 21.13 (70.43%), MSTS score for DF was 21.94 (73.13%) and PT was 19.75 (65.83%) group into good to excellent result. The infection rate was 13% (7 cases) and high in PT endoprosthesis

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group. The early revision rate of endoprosthesis replacement was 11.1% (6 cases) mainly due to infection (3 cases). Infection and at site of endoprosthesis were the cause of early failure.

Conclusion: Endoprosthesis replacement for primary bone tumors had good to excellence MSTS score. There were no different in functional outcome after distal femur endoprosthesis and proximal tibia endoprosthesis. The cause of early failure in our center following endoprosthesis surgery is infection and the location of endoprosthesis replacement which is a proximal tibia.

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ABSTRAK

Pengenalan: Pembedahan Penyelamatan Anggota dalam pembuangan tisu luas di dalam kanser tulang primer akan menyebabkan kehilangan pada segmen tulang. Cara optima untuk membentuk semula pada tulang hujung femur dan pangkal tibia masih lagi kontroversi. Terdapat beberapa cara untuk membentuk semula tulang yang dipotong iaitu

"auto grafts", "allografts", "custom-made megaprosthesis" dan "modular endoprosthesis". Penggunaan "encloprosthesis" ini dapat membolehkan pesakit menjalani proses rehabilitasi dengan. cepat dan memberi keputusan fungsi yang terbaik kepada pesakit kanser tulang. Tujuan kajian ini di jalankan adalah untuk menilaikan semula kebolehan pesakit selepas pembedahan "endoprosthesis" dalam kanser tulang ptimer di hujung tulang femur dan pangkal tulang tibia dengan menggunakan sistem markah MSTS.

Metodology: Lima puluh empat pesakit berturut-turut dalam kanser hujung tulang femur dan pangkal tulang tibia telah dipilih untuk dinilai semula dalam kebolehan fungsi selepas pembedahan "endoprosthesis" dengan menggunakan sistem markah MSTS.

Keputusan: Didapati 34 pesakit (63%) mengalami kanser hujung tulang femur dan 20 pesakit (37%) men,galami kanser pada pangkal tulang tibia. Kanser tulang osteosarkoma primer adalah 33 kes (61.1 %) dan peringkat III OCT adalah 20 kes (37%). Purata umur pesakit adalah 26.6±1 0.61. Dua belas pesakit mengalami pembiakan kanser ke paru-paru.

Pemjumlahan purata MSTS pada kedua-dua hujung femur dan pangkal tibia adalah 21.13 (70.43%), markah MSTS pada hujung femur adalah 21.94(73.13%), markah MSTS pada

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pangkal tibia adalah 19.75(65.83%). Ini menunjukkan keputusan yang baik ke terbaik di dalam pembedahan "endoprosthesis" ini. Paras jangkitan kuman adalah 13%(7 kes) dan jangkitan adalah tinggi pada tulang pangkal tibia. Paras pembedahan "endoprosthesis"

semula pada peringkat awal adalah 11.1% (6kes). Majoriti pembedahan semula ini adalah disebabkan oleh infeksi.

Kesimpulan: Pembedahan "endoprosthesis" dalam kanser tulang primer adalah baik ke sangat baik pada markah MSTS. Didapati tiada perbezaan yang signifikan dalam markah MSTS pada hujung tulang femur dan pangkal tulang tibia. Punca utama kegagalan pada pembedahan "endoprosthesis" ini adalah infeksi dan kedudukan "endoprosthesis"

tersebut..

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Chapter 1:

Introduction

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Chapter 1: Introduction

The distal femur and the proximal tibia is the most common location for bony tumor lesions. In the 1970s, the primary treatment for these lesions was amputation. With advances in radiation treatment, chemotherapy and endoprosthesis, limb salvage became an option in the early 1980s. Although there appears to be a higher incidence of local recurrence with limb salvage, the overall patient survival is similar to that for amputation.

The development of new operative techniques, better patient selection and improved prosthetic design have improved the functional outcome ofL.S.S.

The optimum method for reconstruction of the lower limb after resection of the femur or tibia is controversial. Options include the use of autografts, allografts, custom-made megaprostheses and modular endoprostheses. Endoprosthesis allows early ambulation rehabilitation with a good long term functional outcome result.(Zeegen, Aponte-Tinao et al. 2004)

Improvements in the treatment of primary bone neoplasms have led to an increase in the long-term survival of the patients. Many of them are young and are expected to lead active lives, placing greater demands on their implants, whilst those with metastatic . disease are anticipated to have poor bone quality, possibly placing a greater load on the . endoprosthesis. Accordingly, durability of the implant is . important in reducing the

likelihood of revision.

The aim of this study is to evaluate the functional outcome of patient in modular endoprosthetic reconstructions surgery in the treatment of primary bone tumors of distal

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femur and proximal tibia of the lower limb, by using Musculoskeletal Tumor Society scoring system. We also will determine the cause of early failure following wide resection endoprosthesis reconstruction surgery.

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Chapter 2:

Literature Review

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Chapter 2: Literature Review

2.1 Overview of Bone Tumor

Surgical procedures for limb salvage have been performed for more than a century for primary bone sarcomas of low or moderate grade. In the past decade, advances in adjuvant and neoadjuvant treatment, in diagnostic imaging, and in the surgical techniques for reconstruction of limbs have led to serious consideration of limb-salvage surgery for most patients who have osteosarcoma, the most common high-grade sarcoma of bone.

Bone tumors are a rare and heterogeneous group of tumors. Although bone comprise 75% of the average body weight, these neoplasms represent less than 1% of all adult and 15% of pediatric malignancies. The annual incidence in the United States, which remains relatively constant, is approximately 2500 bone tumors.(Malewar 2001) Because these lesions are so rare, few pathologists have sufficient experience to deal comfortably with their diagnosis. This is further compounded by the steady evolution in the classification of bone tumors, which is based on their biological behavior, ultrastructure, and results of immunohistochemical and cytogenetic studies.

2.1.1 Biology Behavior of Tumor

Tumors arising in bone and soft tissues have characteristic patterns of biological behavior because of their common mesenchymal origin and anatomical environment. Those unique patterns form the basis of the staging system and current treatment strategies. Histologically, sarcomas

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are graded as low, intermediate, or high grade. The grade is based on tumor morphology, extent of pleomorphism, atypia, mitosis, and necrosis.

It represents its biological aggressiveness and correlates with the likelihood of metastases. Sarcomas form a solid mass that grows centrifugally with the periphery of the lesion being the least mature. In contradistinction to the true capsule that surrounds benign lesions, which is composed of compressed normal cells, sarcomas are generally enclosed by a reactive zone, or pseudocapsule. This consists of compressed tumor cells and a fibrovascular zone of reactive tissue with a variable inflammatory component that interacts with the surrounding normal tissues. The thickness of the reactive zone varies with the histogenic type and grade of malignancy. Highgrade sarcomas have a poorly defined reactive zone that may be locally invaded by the tumor.

In addition, they may break through the pseudocapsule to form metastases, termed "skip metastases", within the same anatomic compartment in which the lesion is located. By definition, these are locoregional micrometastases that have not passed through the circulation. This phenomenon may be responsible for local recurrences that develop in spite of apparently negative margins after a resection. Although low-grade sarcomas regularly interdigitate into the reactive zone, they rarely form tumor skip nodules beyond that area. Sarcomas respect anatomical borders. Local anatomy influences tumor growth by setting natural barriers to extension. In general, sarcomas take the path of least resistance

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and initially grow within the anatomical compartment in which they arose.

In a later stage the walls of that compartment are violated (either the cortex of a bone or aponeurosis of a muscle), and the tumor breaks into a surrounding compartment. Most bone sarcomas are bicompartmental at the time of presentation; they destroy the overlying cortex and extend directly into the adjacent soft tissues.

Direct tumor extension through the articular cartilage is rare and usually occurs as the result of a pathological fracture with seeding of the joint cavity or by pericapsular extension. Occasionally, structures that pass through the joint (e.g., the cruciate ligaments) act as a conduit for tumor growth. Transcapsular skip nodules are demonstrated in 1% of all osteosarcomas. (Enneking 197 5)

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2.1.2 Classification of primary tumors ofbone(Frassica et al. 2004):

Table 2.1: Classification of primary tumors of bone

Histology Type Benign Malignant

Hematopoietic Myeloma

Lyphoma

Chondrogenic Osteochondroma Primary Chondrosarcoma

Chondroma Secondary Chondrosarcoma

Chondroblastoma Dedifferentiated Chondromyxoid fibroma Chondrosarcoma

Mesenchymal Chondrosarcoma Clear Cell Chondrosarcoma Osteogenic Osteoid Osteoma Parosteal Osteosarcoma

Osteoblastoma Periosteal Osteosarcoma Unknown Origin Giant Cell Tumor Ewing's tumor

Fibrous Histiocytoma Malignant Giant Cell Tumor Adamantinoma

Fibrogenic Fibroma Fibrosarcoma

Desmoplastic fibroma Malignant fibrous histiocytoma

Notochordal Chordoma

Vascular Hemangioma ·Hemangioendothelioma

Hemangiopericytoma

Lipogenic Lipoma

Neurogenic Neurilemoma

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2.1.3 Etiology of Bone Tumor

The cause of bone tumors is unknown. They often arise in areas of rapid growth. Possible causes include inherited mutations, trauma, and radiation, but in most cases no specific cause is found.

Risk factors for bone tumors include previous radiation therapy, exposure to chemicals (e.g., vinyl chloride, arsenic), immunodeficiency, prior injury (scars, burns), chronic tissue irritation (foreign-body implants, lymphedema), neurofibromatosis, Paget's disease, bone infarcts, and genetic cancer syndromes (hereditary retinoblastoma, Li- Fraumeni syndrome, Gardner's syndrome). In most patients, however, no specific etiology can be identified.

Malignant bone tumors include osteosarcomas, Ewing's sarcoma, fibrosarcoma, and chondrosarcoma The most common cancers that spread to the bone are cancer of the breast, lung, prostate, kidney, and thyroid. These forms of cancer usually affect older people.

Bone cancer was once prevalent among individuals who painted radium on watch faces (to produce glow-in-the-dark dials). The painter would 'tip' the brush with their tongue (in order to produce fine work) and absorb minute amounts of radium, which deposited in the bone and caused cancer. The practice of using radiuni paint was abandoned in the middle of the 20th century.

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The incidence of bone cancer is also increased in families with familial cancer syndromes. The incidence of bone cancer in children is approximately 5 cases per million children each year.

2.2 Evaluation of Bone Tumor

2.2.1 Clinical Presentation

The main presentation of bone tumor is a bone pain, may be worse at night. Occasionally a mass and swelling can be felt at the tumor site which is slightly tender or non tender. Bone fracture, especially fracture from slight trauma (injury) can be happened as coincidence finding.

Note: Some benign tumors have no symptoms.

2.2.2 Physical Examination

Patients with suspected bone tumors should be examined carefully. The affected site is suspected for soft tissue mass, overlying skin changes, adenopathy, and general musculoskeletal condition. When metastatic disease is suspected the thyroid gland, ab<lomen, prostate and breast should be examined as appropriate.

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2.2.3 Radiology

2.2.3 .1 Plain Radiograph - is an important modality in evaluation of bone tumor. It is an accurate diagnosis of bone tumors can be made in more than 80% of cases.

2.2.3.2 C.T. scan- is the imaging modality of choice to evaluate the extent ofbone destruction. The slice thickness should be done at least 10-

15 slices through the tumor(Barry Shmookler, Malawer et al.

2001 ). Intravenous contrast dye should be employed in the evaluation of soft-tissue tumors unless a clear contraindication for its use exists.

2.2.3.3 MRI- has been proven to be superior to CT in the evaluation of the intramedullary and extraosseous, soft-tissue extent of bone tumors.

The signal intensity of a tumor is assessed by comparing it with that of the adjacent soft tissues, specifically skeletal muscle and subcutaneous fat. MRI also enables one to view a lesion in all three planes (axial, sagittal, and coronal). MRI is useful in evaluating the relationship of a tumor to the adjacent blood vessels and in characterizing cystic lesions.

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2.2.4 Biopsy

Biopsy is a key step in the diagnosis of bone tumors. An inadequately performed biopsy may fail to allow proper diagnosis, have a negative impact on survival, and ultimately necessitate an amputation to accomplish adequate margins of resection. Poorly performed biopsy remains a common finding in patients with musculoskeletal tumors who are referred to orthopedic oncology centers. The principles by which an adequate and safe biopsy of musculoskeletal tumors should be planned and executed are reviewed and a surgi~al approach to different anatomic locations is emphasized. The biopsy is the final step in the staging process and should be performed at the institution where the definitive procedure will ultimately take place.(Mankin HJ 1996) Regardless of whether an open or core needle biopsy is performed, strict principles need to be adhered to for limb salvage surgery. The biopsy should be placed in line with the anticipated surgical excision to allow for complete resection of the biopsy tract. Also, the biopsy should traverse one compartment only, and postoperative hematomas should be carefully avoided.

An

incorrectly performed biopsy can render limb salvage impossible.
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2.3 Staging of Bone Tumor

Staging is the process of classifying a tumor, especially a malignant tumor, with respect to its degree of differentiation, as well its local and distant extent, in order to plan the treatment and estimate the prognosis. Staging allows the surgeon to determine the type and the extent of the operation that is necessary for a specific type of tumor in a particular anatomic location, as well as the indication for neoadjuvant treatment modalities. Staging of a musculoskeletal tumor is based on the findings of the physical examination and the results of imaging studies. The most popular and useful staging is Enneking system. Biopsy and histopathological evaluation is an essential component of staging, but should always be the final step(Barry Shmookler, Malawer et al. 2001 ).

The Enneking system for the surgical staging of bone and soft-tissue tumors is based on grade (G), site (T), and metastasis (M) and uses histologic, radiologic, and clinical criteria. It is the most widely used staging system and has been adopted by the Musculoskeletal Tumor Society.(Enneking, Dunham et al. 1990) The system should be reserved for staging mesenchymal lesions rather than nonmesenchymal ones (such as the lesions of Ewing sarcoma, lymphoma, and leukemia), because the biologic behavior of nonmesenchymal tumors diff~rs from that of mesenchymal lesions. For example, studies have shown that the site of occurrence of Ewing sarcoma is not a significant factor when tumor size is considered.

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In the Enneking system, bone tumors are graded as follows:

• GO - Benign lesion

• G I - Low-grade malignant lesion

• 02 - High-grade malignant lesion

Surgical grade generally follows histologic grade; however, a higher surgical grade may be applied if the radiographic features and clinical behavior of a lesion indicate an aggressiveness that is incompatible with its benign histologic features.

In the Enneking system, the site and local extent of bone tumors are classified as follows:

• TO - A benign tumor that is confined within a true capsule and the lesion's anatomic compartment of origin (ie, a benign intracapsular, intracompartmental lesion)

• Tl- An aggressive benign or malignant tumor that is still confined within its anatomic compartment (ie, an intracompartmentallesion)

• T2 - A lesion that has spread beyond its anatomic compartment of origin ( eg, an extracompartmentallesion)

Metastatic classification in the Enneking system is as follows:

• MO - No regional or distant metastasis

• Ml- Regional or distant metastasis

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Staging

Under the Enneking system, malignant tumors are classified into stages I-III, with further subdivisions into A and B. Grade 1 and grade 2 tumors are stage I and stage II, respectively. T1 and T2 tumors are stage A and stage B, respectively. Tumors with distant metastasis are stage III (see table 2.2 below).

Table 2.2: Enneking System for the Surgical Staging of Malignant Bone and Soft- Tissue Tumors

I

Stage

I

Grade

I

Site

I

Metastasis

I

lA -~-··ai---~--

Tl

I

MO

I

IB

I

02

I

T2

I

MO

I

IIA

I

02

I

Tl

I

MO

I

liB

I

02

I

T2

I

MO

I

III

I

Gl orG2

I

Tl orT2

I

M1

The Enneking classification correlates the tumor stage with the excision margins as follows:

• Benign tumors

o Stage 1 tumors - Intracapsular excision (or curettage) is adequate.

o Stage 2 tumors - Extracapsular excision passing through the reactive zone is needed.

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o Stage 3 tumors - Wide margins of resection are required in stage 3 lesions (aggressive benign tumors). In areas that are not amenable to wide excision, marginal excision together with adjuvant treatment ( eg, radiation therapy) may be acceptable.

• Malignant tumors

o Stage lA - These tumors are treated with wide excision and are usually amenable to limb salvage procedures.

o Stage

m -

Such tumors may be treated with wide excision, but the choice between amputation and limb salvage depends on the estimated amount of residual tumor left behind after a limb salvage procedure.

o Stage II - These tumors are high grade, are usually extracompartmental, and have a significant risk for skip metastases. They usually are not amenable to limb salvage operations and require radical amputation or disarticulation in most patients. However, bone tumors responsive to chemotherapy may be treated successfully using wide excision and adjuvant therapy.

o Stage III - Tumors at this stage are responsive to chemotherapy and may be treated with aggressive resection. Those that are not responsive to adjuvant therapy should be treated with palliative resection.

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2.4 Overview Management of Bone Tumor

2.4.1 History

Limb salvage surgery includes all of the surgical procedures designed to accomplish removal of a malignant tumor and reconstruction of the limb with an acceptable oncologic, functional, and cosmetic result. In the recent past, most sarcomas were treated by amputation.(J.S.M. and B.J.S.A.

1988:70-A:307-10. 1988) Tumor recurrence, metastasis, and a generally dismal prognosis were a powerful deterrent to progress in treatment. Limb salvage surgery has all but replaced amputation as the treatment of choice for sarcomas of the extremities.(Postma A, et al1992:51:47-51. 1992) This dramatic change came about as the result of two important developments:

effective chemotherapy and precision imaging techniques. In the early 1970's, new antineoplastic drugs such as adriamycin and methotrexate were introduced, and remarkable improvements in the prognosis for some sarcomas were seen. In the late 1970's, the development of CT and MRI allowed doctors to more precisely define the anatomic extent of the tumor, making it easier to remove the sarcoma without resorting to amputation.

Today, up to 85% of sarcoma.S in the extremities are treated with limb salvage surgery.

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2.4.2 Role of Chemotherapy

Chemotherapy was used initially to treat metastatic disease and, more recently, in an attempt to increase survival after local treatment and to also maximize the number of candidates for limb-sparing surgery(Malawer 2001). Neoadjuvant therapy has primarily been utilized for patients with large primary or recurrent sarcomas, usually with the goal of permitting a limb-sparing operation in patients in whom amputation may otherwise have been necessary or for converting a marginally respectable tumor to one that can be adequately resected with preservation of extremity function.

One of the goals of treatment before limb-sparing surgery is to shrink the tumor, allowing for a more successful surgical outcome. Chemotherapy drugs have been developed to kill malignant (cancerous) cells, while hopefully shrinking the tumor. Specific chemotherapy drugs are part of the treatment plan before and after surgery for the patient with primary bone cancer. Neoadjuvant chemotherapy is used in an effort to increase the number of patients who are considered candidates for limb-sparing surgery and to provide a more positive outcome for surgery.

Chemotherapy usually is a~stered for approximately three or four months before the limb-sparing .surgery.

The best regimen, in terms of specific drugs, drug/dose sequence, and route is not known at this time; also unknown is whether radiation therapy is necessary for all patients. However, neoadjuvant chemotherapy should

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be considered for patients who have traditionally been thought to be at high risk for local recurrence (i.e., patients with large, deep-seated, high grade, extremity sarcomas)(Malawer 2001). Neoadjuvant therapy help downstage a tumor by reducing the size of an accompanying soft tissue mass and forming a surrounding reactive rim that would confine the tumor within a calcified periosteum. This could lead to better tumor demarcation and permit successful tumor removal with a limb sparing resection.

2.4.3 Surgery

2.4.3.1 Amputation

Amputation is to remove all or part of an arm or leg when the tumor is large and/or nerves and blood vessels are involved. Barriers to limb salvage include poorly placed biopsy incisions, major vascular involvement, incasement of a major motor nerve, pathological fracture of the involved bone, and others. These adverse factors should not be viewed as absolute contraindications.(Nichter LS 1993)

The so-called "three strikes rule" is a simple but helpful method of assessing the feasibility of limb salvage in any particular case. Each

. .

"strike" represents involvement of one of the four key components needed for a viable limb: the bone, the nerves, the vessels, and the soft tissue envelope. If just one or two of these key components must be resected in

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order to obtain an adequate margin around the tumor, then the limb may be salvageable. If three of these key components are involved, limb salvage is probably not worth considering.(B. J. Hurson and Saint Vincent's Hospital1995)

For high grade tumors, limb salvage might be technically possible and seem like a tempting prospect, but the results are often inferior to amputation.

2.4.3.2 LSS.

This surgery removes the cancerous section of bone but keeps nearby muscles, tendons, nerves, and blood vessels. If possible, the surgeon will take out the tumor and a margin of healthy tissue around it. The excised bone is replaced with a metallic implant (prosthesis) or bone transplants.

The goals of surgeons who treat primary bone tumor of the anns and the legs are the survival of the patient and the salvage of a functional limb.

Various methods of limb salvage have been used for more than a century for benign and low-grade malignant tumors. Since the early 1980s advances in neo-adjuvant chemotherapy have led to an extension of methods to high grade sarcomas of bone. Reconstructive operations include the use of autografts, allograft, prosthetic implants and modified amputations.

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The most frequent method is the use of an endoprosthesis which may be modular or custom-built. When considering whether surgery for limb salvage is justified, it is usual to consider long term oncological results and compare them with the historical results after amputation.(Cannon May 1997) ·

Comparisons can be made in four broad areas:

2.4.4 Overview LSS

a) The overall survival of patients

b) The early and late morbidity for each type of reconstruction

c) The function of the salvaged limb and it maintenance over a prolonged period of follow-up.

d) The quality of life in patients having limb salvage and those having an amputation.

A limb-sparing (otherwise known as limb-salvage) surgery involves removing a malignant (cancerous) bone or soft tissue tumor without amputation, and replacing the bone and/or joint with an allograft (bone graft), endoprostheses (artificial devices), or composite (combining allograft and endoprothesis). Soft tissue and

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muscle transfers to cover and close the site and restore motor power also are part of this procedure.

The aims of limb salvage surgery are to cure disease and to preserve limb function.

The aims are usually achieved by using a combination of limb salvage surgery and adjuvant therapy.

Limb salvage operations are indicated if the following conditions are satisfied:

• The tumor is situated in the extremities and/or the axial skeleton.

• The tumor margins are amenable to surgery.

• Only moderate soft-tissue extension is present.

• The neurovascular bundles are intact.

• Metastases are absent or amenable to curative treatment.

• The patient is in good general health.

Regarding resection margins, optimal surgical margins are 6 em of healthy bone around the bone margins and 2 em of healthy soft tissue around the soft-tissue extent of the tumor. If a malignant tumor is responsive to chemotherapy, smaller resection margins may be acceptable.

In the past, amputation of the affected arm or leg was the most common treatment for many types of primary bone cancers. Primary bone cancer describes cancer cells that originate from the bone and may locally invade the soft tissues. Due to improvements in chemotherapy, imaging studies, and surgical techniques, limb-sparing surgeries are performed more commonly today.(Nancy K. Smith 1999)

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A patient may be a candidate for limb-sparing surgery depending on the tumor size, location, and whether the cancer has spread to other areas of the body, such as other bones or the lungs. The patient's age and skeletal development also are part of the decision that determines the appropriateness of this surgery. Other considerations for limb-sparing surgery include the response to chemotherapy, the extent of bone and soft tissue involvement, and how functional the limb may be after the procedure.

2.4.4.1 Types of Resection

There are four basic types of excisions; each is based on the relationship of the dissection plane to the tumor and its pseudocapsule. An intralesional excision is performed within the tumor mass and results in removal of only a portion of it; the pseudocapsule and macroscopic tumor are left behind. In a marginal excision, the dissection plane passes through the pseudocapsule of the tumor. Such a resection may leave microscopic disease. Wide (en-bloc) excision entails removal of the tumor, its pseudocapsule, and a cuff of normal tissue peripheral to the tumor in all directions.

This is the desired margin for sarcoma resection; however, the adequate thickness of the normal tissue cuff is a matter of controversy. For both soft-tissue and bone sarcomas, it is generally believed to be a few centimeters. The tumor, its psudo-capsule and a cuff of normal tissue peripheral to the tumor are removed en-bloc in all direction. This will have adequate margin for all sarcoma except skip lesions. Skip lesions are

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actually nodules of tumor separated from the primary tumor outside the reactive zone and more often found proximal to the primary lesion but within the region. It wound have the same prognosis as distant metastases, increased incidence of local recurrence and subsequent pulmonary metastases.(Enneking 1975) A margin of 4cm from the reactive zone is defined by Japanese Orthopaedics Association as wide margin.(Guo, Ji et al. 2006)

Radical excision involves removal of the tumor and the entire anatomical compartment within which it is located. Although traditionally mentioned as the fourth excision type, it does not define the component of the tumor that is left behind. In other words, a radical excision can achieve a marginal or a wide margin, depending on how close the tumor is to the border of the compartment. However, radical excision · excludes the possibility of skip metastases. In general, benign bone tumors are adequately treated by either an intralesional procedure (curettage and burr drilling, cryosurgery) or by marginal excision. Primary bone sarcomas are treated with wide excision. Metastatic tumors are treated according to the general Intent of the surgery. When a palliative surgery is performed, metastatic lesions . are treated by an intralesional procedure. If a curative procedure is performed, as in the case of solitary breast metastasis, for example, the lesion is treated as if it was a primary bone sarcoma (i.e., wide excision). It is importa.tlt to emphasize that any of these excision types may be accomplished by a limb-sparing procedure or by amputation.

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An amputation is not necessarily an adequate cancer operation, but it is a method of achieving a specific margin. It may entail a marginal, wide, or radical excision, depending upon the plane in which it passes. Staging studies are used to assess local tumor extent and relevant local anatomy, and thereby determine how a desired surgical margin may be achieved.

SOFT TISSUE _.,.--..

SARCOMA f ,

Marginal excision

excision

\\ ~~

Radical excision

Marginal excision

Radical excision

Figure 2.1: Various excision types for soft-tissue and tumors sarcoma (Copy from Malewar Book, Chapther 1)

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2.4.4.2.1

Resection-arthrodesis is aimed at restoring a stable skeletal continuity. It is particularly preferred after resection of an aggressive benign lesion around the knee in overweight patients.(FH 1991)

The limb salvage surgical procedure is a multistage protocol requiring tumour staging investigations: plain radiographs, :MRI, CT -scans of the thorax and bone scanning prior to a diagnostic bone biopsy. The patient is then subjected to pre-operative neo-adjuvant chemotherapy following early available histological diagnosis. All these steps should not delay the treatment.

Autograft

Of the 300,000 procedures performed in 1998, 9 of 10 involved the use of either autograft or allograft tissue. The current standard is for autograft tissue bone grafts, in which tissue is harvested from the patient, usually from the iliac crest, but possibly from the distal femur or the proximal tibia. The graft is then placed at the injury site. This tissue is ideal

as

a bone graft because it possesses all of the characteristics necessary for new bone growth-namely, osteoconductivity, osteogenicity, and osteoinductivity.

Osteoconductivity refers to the situation in which the graft supports the attachment of new osteoblasts and osteoprogenitor cells, providing an interconnected structure through which new cells can migrate and new

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2.4.4.2 Osseous Reconstruction

Reconstruction is the procedure to rebuild the bone and soft tissue defects created by wide resection of tumor. The procedures include the use of segmental allograft, allograft-prothesis composites, segment of bone autograft (such as vascularized fibular graft), prosthetic joint replacement prosthesis or arthodesis. The choice of the procedure must be individualized to tailor individualized to tailor individual requirement of each patient.

The aim of surgery is to provide the simplest reconstructive technique which may allow primary wound closure. Methods of closing soft tissue defect created by resection of tumour mass include primary closure if possible or by using muscle flap, which is either free or pedicled. Soft tissue reconstruction is equally important in completing the LSS. Its advantage outweighs the disadvantage of cosmetic appearance of slight deformity. In most instances, it is performed in conjunction with plastic reconstructive surgeons. Technique of wound closure is considerably important as it hasten healing process by bringing in blood supply and thus, helps to prevent infection. The bulk of tissues used for soft tissue reconstruction helps to protect the allograft or endoprosthesis and giving form to the limb.

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2.4.4.2.2

vessels can form. Osteogenicity refers to the situation when the osteoblasts that are at the site of new bone formation are able to produce minerals to calcify the collagen matrix that forms the substrate for new bone.

Osteoinductivity refers to the ability of a graft to induce nondifferentiated stem cells or osteoprogenitor cells to differentiate into osteoblasts.

Harvesting the autograft requires an additional surgery at the donor site that can result in its own complications, such as inflammation, infection, and chronic pain that occasionally outlasts the pain of the original surgical procedure. Quantities of bone tissue that can be harvested are also limited, thus creating a supply problem.

The vascularised fibular graft is the most common autograft successfully used in the reconstruction of the large skeletal defect following tumor resection with union achieved at an average 7.6 months in 90% of the patient.(R.H. 1997) It has advantage of having ability to become hypertrophy once subjected to stress during weight-bearing mobilization.

Allograft

Allograft is defined as tissue transferred between two genetically different individuals of same species. It is first used in early 20th century. Lexer, 1907 is first person to performed allograft for whole joint transplantation.

Now it is widely used in tumour, arthroplasty, joints reconstruction and

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spine surgery. More than 150,000 musculoskeletal allografts used by orthopaedic surgeon in US annually. Types of bone allogarfts are Fresh allograft, Deep freeze allograft, Freeze-dried allograft, Morcellized cancellous allograft and bone chip demineralized bone matrix. Allograft is used as, fill big defect, as structural support, for reconstruction the joint and to fill up the cavity defect. The advantages of bone allograft are, reconstruction of ligament, reconstruction of tendinous structures, reconstruction of joint capsules, we able to resize and reshape and biological incotporation. Osteoarticular allograft loses more than 50% of its living chondrocytes during the process of preservation when glycerol or dimenthyl sulfoxide is used in freezing technique. At the time of surgery during thawing process, only 10% to 35% of these cryopreserved chondrocytes remained viable. The advantage of osteoarticular allograft reconstruction is a biologic replacement of only the involved portion of the joint. It has a location for reattachment of tendons, ligaments and capsule to the allograft. While graft incotporation progresses after the initial bony healing has occurred, the subchondral and metaphyseal areas weaken significantly to an extent that fracture and collapse of the bone with subsequent graft failure may occur.(RM 1993) The knee, being · highly stressed onn weight-bearing, has a high complication . rate

· approaching 50% - 60%. The resurfacing prosthesis obviates the problems of resotption and osteoarticular collapse.

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2.4.4.2.3

Mankin et al, in their series had observed that susceptibility to infection was 10% after the first year and the risk of fracture increased to 19% by the third year before the grafts become stable and maintained for more than 20 years in about 75% of the cases.(Mankin HJ 1996)

Endoprosthesis

The earliest published example of an endoprosthetic reconstruction following treatment of a bone tumor dates to 1940, when Austin Moore and Harold Bohlman implanted a vitallium proximal femur in a patient with a giant-cell tumor. In the early 1970s Kenneth Francis and Ralph Marcove ushered in the current age of endoprosthetic reconstruction following radical resection of osteosarcomas by developing a distal femoral and a total femoral replacement, respectively. This new concept of limb-sparing surgery for sarcoma patients was based on the hope that Adriamycin and methotrexate, newly introduced for osteosarcoma in the early 1970s, would permit a safe limb-sparing resection in lieu of primary amputation. However, it was soon recognized that the 6-8 week lag time between diagnosis and the creation of a custom endoprosthesis for a given patient could have a negative impact on survival. As a result, Gerry Rosen and Ralph Marcove invented the concept of induction (i.e. preoperative or neoadjuvant) chemotherapy, according to which patients with osteosarcomas received chemotherapy during the interval from time of diagnosis of the tumor to the delivery of that patient's custom implant.

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Induction chemotherapy 1s now administered to patients with a wide variety of cancers.

A B

c

Figure 2.2: Custom distal femoral prostheses used between 1982 and 2000. (Knee component not shown) (Courtesy Howmedica Inc., Rutherford, NJ).

(A) Original custom prosthesis (1982).

(B) Custom prosthesis (1984-1988) with porous collar (solid arrow) to permit extracortical bone fixation and soft tissue attachments (1984-1988).

(C) Modular segmental prosthesis. This was the original segmental design (1988) which is currently in use today with some modifications

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Figure2.3: Modular replacement system (Howmedica, Inc.). A distal femoral Modular Replacement System showing the stem, body, and condyles with the tibial insert (polyethylene) in which a tibial bearing plug (metal) is inserted. ((Courtesy Malewar Book)

Endoprosthetic replacement of segmental skeletal defects is the preferred technique of reconstruction after resection of bone sarcomas. Today, all of the major anatomic joints with their adjacent segmental bone can be reconstructed safely and reliably with a modular endoprosthetic replacement. Prosthetic reconstruction is routinely performed for the proximal femur, distal femur, total femur, proximal tibia, proximal

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humerus, and scapula. Allografts are rarely used. A major advantage of a modular endoprosthetic system is intraoperative flexibility; it enables the surgeon to reconstruct defects of any size with minimal preoperative planning. Instead of performing a resection to match a prosthesis customized on the basis of imaging studies that are 4-8 weeks old, the surgeon can concentrate on performing the best possible resection indicated for the patient at the time of surgery. Overall survival analysis of large segmental replacements is approximately 90% at 10 years (reported at 98% for the proximal humerus and 90% for the distal femur).(Malawer 2001)

Before the development of endoprostheses in the 1970s, the primary treatment for these lesions was amputation. With advances in radiation treatment and chemotherapy, limb salvage became an option in the early 1980s. Although there appears to be a higher incidence of local recurrence with limb salvage, the overall patient survival is similar to that for amputation(Ahlmann et al. 2006). The development of new operative techniques, better patient selection and improved prosthetic design have been instrumental in improving the options for treatment.

The optimum method for reconstruction of the lower limb after resection of the femur or tibia is controversial. Options include the use of autografts, allografts, custom-made megaprostheses and modular endoprostheses. The first reconstructive procedures were performed using allograft or allograft-

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prosthetic composites.(Donati, Giacomini et al. 2002) Nonunion, fracture and infection often complicate the use of allografts. Custom-made endoprostheses were then developed which, while associated with fewer complications, were costly to manufacture.(Kabukcuoglu Y 1999) More recently modular endoprostheses have become available. These allow reconstruction of a wide variety of skeletal defects using off-the-shelf components without the expense or time required to manufacture a custom-made implant.(Ahlmann, Menendez et al. 2006)

Currently, a high percentage of these patients can be treated with limb- salvage surgery with no adverse effect on patient survival. The principles of oncologic surgery remain the same regardless of the type of reconstruction that is ultimately chosen. A wide margin must be obtained at the time of surgery. Major neurovascular structures ideally should not be involved, although in select cases a major nerve can be resected if the resultant extremity still would prove to be more functional than an amputation and external prosthesis.

The ideal reconstruction technique allows early mobilization and rehabilitation, does not interfere with ongoing chemotherapy and radiation, provides excellent function, is durable, and has an acceptably low complication rate(Christopher P. Cannon 2005). Options include an endoprosthesis, osteoarticular allograft, allograft-prosthesis composite, arthrodesis, and rotationplasty. Lastly, an amputation must always be

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considered if wide margins cannot be obtained with a limb-salvage procedure or if the resultant limb function would be worse with limb salvage and reconstruction than with amputation and prosthesis.

In comparison with amputation, endoprosthetic replacement of the knee joint has been reported to be associated with good functional and cosmetic results and with psychological benefits. Gait analysis has shown that patients who have had an endoprosthetic replacement consume less oxygen than those who have had an amputation. Patients who have had a rotationplasty walk more efficiently and at a faster rate than those who have had an arthrodesis of the knee. (Hillmann, Hoffinann et al. 1999)

Custom-made prostheses allow early return of function but are liable to undergo loosening, wear and breakage. There is discussion as to whether skeletal reconstruction is best undertaken by endoprostheses or allografts.

The decision as to which reconstructive technique should be used depends on the location and extent of the tumour spread and the preference of surgeon and patient.(Abudu, Carteret al. 1996)

When limb salvage or amputation is considered for a patient who has osteosarcoma, these concerns should be discussed with the patient and the family. Limb salvage results in a small increase in the rate of local recurrence, and patients who have a local recurrence most often die.

However, the incidence of local recurrence after limb salvage performed by experienced surgeons, using wide surgical margins and adjuvant or

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neoadjuvant chemotherapy, is sufficiently low (5 to 10 per cent) not to have a biologically significant impact on the rate of long-term survival.

After limb salvage, the incidence of morbidity increases, with a few patients occasionally requiring prolonged or repeated hospitalization and additional surgical procedures, even amputation. The durability of the reconstructions is variable, and many of the mobile knee reconstructions will need to be revised if the patients become long-term survivors. The function of salvaged limbs is better than that after amputation, but none of the reconstructions will give normal function.(Simon 1988)

Endoprostheses have revolutionized the field of limb salvage. Prostheses used for reconstruction of tumors must replace both the joint surface and a large segment of bone adjacent to the joint. Ten years ago, most of these endoprostheses were custom-made and required four to six weeks' preparation, precluding their use in urgent situations. Today, we have almost immediate access to these prostheses. Prostheses can be implanted with or without bone cement.

An endoprosthesis has a lower risk of early complications, but the likelihood of needing additional surgery is higher. The life span of these prostheses is limited to an average of 15 years, sometimes less. This means that a young person having a reconstruction of this type is almost certain need a revision in the future. Revisions can usually be done without compromising the functional result, but are costly and preferably

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avoided. Endoprostheses offer immediate postoperative stability, rapid rehabilitation, off-the-shelf availability, and a lower infection rate. The current modular prosthetic systems also offer tremendous intraoperative flexibility. The increasing use of endoprostheses in limb-salvage and increasing demands on reconstruction longevity dictate that factors affecting survival of these reconstructions be investigated.(Jesse T.

Torbert and Christian M. Ogilvie 2005)

A major advantage of a modular endoprosthetic system is intraoperative flexibility; it enables the surgeon to reconstruct defects of any size with minimal preoperative planning. Instead of performing a resection to match a prosthesis customized on the basis of imaging studies that are 4-8 weeks old, the surgeon can concentrate on performing the best possible resection indicated for the patient at the time of surgery. Overall survival analyss of large segmental replacements is approximately 90% at 10 years (reported at 98% for the proximal humerus and 90% for the distal femur).(Malawer 2001)

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Picture of Limb Salvage Surgery in Distal femur and Proximal tibia bone tumors done in HUSM by using modular endoprosthesis system.

Limb salvage surgery using endoprosthesis as osseous reconstruction in distal femur in HUSM.

Wide resection was done in distal femur bone tumor.

Distal femur bone was resected

Howmedica-Stryker endoprosthesis system was used to reconstruct the bone defect.

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Limb salvage surgery in proximal tibia bone tumor in HUSM

Wide resection of proximal tibia bone tumor.

Proximal tibia bone tumor was resected

HowmediCa-Stryker endoprosthesis system was used to reconstruct the bone defect.

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2.4.4.2.4 Alloprosthesis

Alloprosthesis can be viewed as a transitional step between allografts and endoprostheses. This procedure became popular when surgeons began to abandon pure osteoarticular allografts. Alloprosthesis were thought to provide the benefits of a biologic reconstruction along with the immediate stability achieved by a cemented endoprosthesis. Experience has shown that this method has the same high rate of early complications (i.e.

infection and nonunion) as does standard allograft reconstruction.

Accordingly, this method is better suited for a patient undergoing revision of a failed allograft, rather than a patient undergoing chemotherapy for a sarcoma.(Hejna MJ 1997)

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2.5 Outcome of Surgery

The goals of amputation in tumor surgery are to achieve local control by wide resection margin of the tumor bearing bone and soft tissue, and to reconstruct the residual limb to be as functional outcome is obtained when the amputation is performed at the lowest level possible. Therefore, transtibial amputations fare better than knee disarticulations, and low transtibial amputations and knee disarticulations have better functional outcomes than high transfemoral amputation.(Persson 2001)

Similarly, the primary goals of LSS are to provide local control of the tumor by wide resection margins, reconstruction of the defect to restore, as much as possible, function of the involved limb without compromising survival or prognosis.

Amputation for distal femur osteosarcoma did not improve the survival rate compared to LSS.(Simon, Aschliman et al. 1986) Long term survival was not influenced by limb preserving surgery or amputation or rotationplasty, provided adjuvant chemotherapy was efficiently given.(Kotz RK)

With regards to the rate of recurrence, both limb salvage surgery and above the knee amputation and similar incidence of 10% compared . to 0% for hip disarticulation. Therefore a local recurrent is probably due to skip lesion or skip metastasis. Though LSS increases the local recurrence rate of 10%, it does not

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adversely affect disease-free interval and long term survival. There is no risk of increased mortality.(Simon, Aschliman et al. 1986)

2.5.1 Limb Salvage versus Amputation

LSS has became more commonly performed as indicated by more than 80%

patients with extremity osteosarcoma were currently treated with LSS in many centres. The survival of the patients with either limb salvage or amputation was similar, even though higher rates of local recurrence in patients with LSS have been reported.(Rougraff BT 1994) It is generally accepted that, provided the surgery is carried out in an appropriate oncological manner, there is no detriment to the survival of the patients treated with LSS in a variety of techniques.

In addition to the issue of equivalent survival rates between amputation and LSS, there were concerns that would be higher local recurrence rates following limb salvage, since local recurrence of OS has been associated with poor outcome.(BM 2002) Consensus has emerged that limb salvage procedures produce equivalent rates of disease free survival when compared with amputations, as seen in a number of studies.(Simon, Aschliman et al. 1986) Multiple studies have also shown that the incidence of local relapses in those with amputations and LSS are not significantly different, with rates between 1% and 11 %.(Sluga M 1999) Major predictors of local recurrence in these studies included surgical margin and tumor responsiveness (necrosis) to chemotherapy. Overall, the availability of improved imaging techniques and the resultant improved surgical margins along with adjuvant chemotherapy have made LSS an acceptable method of local control.

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2.6 Functional Evaluation of Reconstructive Procedures

The need for a standardized system of end result reporting of various surgical alternatives after limb salvaging and ablative procedures for musculoskeletal tumors was clearly recognized during the first International Symposium on Limb Salvage (ISOLS) in 1981.

During the ensuing four biannual symposia, there has been an ongoing developmental experience with a system extensively field tested in 1989 by the Musculoskeletal Tumor Society (MSTS). This system of functional evaluation has been adopted by the MSTS and ISOLS for their joint studies and program presentation. In brief, the system assigns numerical values (0-5) for each of six categories: pain, and function and emotional acceptance in upper and lower extremities; supports, and walking and gait in the lower extremity; and hand positioning, and dexterity and lifting ability in the upper extremity.

Demographic information and a patient satisfaction component is included. A numerical score and percent rating is calculated to allow for comparison of results. The system has been field tested in 220 patients with low (+/-) interobserver variability. It was well accepted by the participants, and its usage is recommended by the MSTS to facilitate valid comparative end result studies of musculoskeletal tumor reconstructions.(Enneking, Dunham et al. 1993)

2.6.1 M.S.T.S. functional evaluation

The system of functional evaluation was assessed with the scoring system developed by the Musculoskeletal Tumor Society, as described by Enneking et al.(Enneking 1993) This score is based on an analysis of factors pertinent to the patient as a whole

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(pain, emotional acceptance, and restriction in activities of daily living and work) and factors specific to the affected extremity (use of external supports, walking ability, and gait). Each of these six factors was assigned a value of 0 to 5 points (maximum overall score, 30 points) on the basis of established criteria. This scoring system is an observer score.

Below are the criteria for evaluation in MSTS system:

a) Pain

The value for pain is determined by the amount and effect of the pain on the patients function. The required information is the medication or equivalent measures currently used by the patient for pain relief.

Table 2.3: MSTS pain description

NO. Description Data

5 No pain No medication

4 Intermediate

3 Modest/Non disabling Non-Narcotic analgesics

2 Intermediate

1 Moderate/ Intermittently disabling Intermittent narcotics 0 · Severe/ Continuously disabling Continuous narcotics

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b) Function

The value for function is determined by the restrictions in activities actual or prohibited and the effect of these restrictions on the patient's lifestyle. The required data are pretreatment occupation and the degree of occupational disability caused by the restriction.

Table 2.4: MSTS functions description

NO Description Data

5 No restriction No disability

4 Intermediate

3 Recreation restriction Minor disability

2 Intermediate

1 Partial Occupational restriction Major disability 0 Total Occupational restriction Complete disability

c) Emotional Acceptance

The value for emotional acceptance is determined by the patients' emotional reaction to or perception of the functional result.

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Table 2.5: MSTS emotional description

NO Description Data

5 Enthused Would recommend to others

4 Intermediate

3 Satisfied Would do again

2 Intermediate

1 Accepts Would repeat reluctantly

0 Disl

Rujukan

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