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BENIGN BONE TUMORS()

Kocher92 have reported in a average 10.9 years study that reconstruction of the distal aspect of radius with use of an Osteoarticular Allograft was associated with low rate of recurrence of the tumor, a moderately high rate of revision, little pain, good function and a moderate range of motion. Dean42 have reported in an average study of 7.5 years that the procedure of elbow Allograft for reconstruction of the elbow with massive bone loss due to tumor resection is appropriate and have recommended it for routine use. Bohm23 have reported the formation of massive callus in the central part of a massive Allograft implanted in the proximal femur of patient 22 years back. Mankin98 have reported a 24 years study involving 870 massive frozen Allograft and showed the long term results of Allograft replacement in the management of bone tumors with a positive result of 75 %.

Classification: The World health Organization (WHO) has published a classification of bone tumors that represents one of the most accepted system (Table 2).

1. Bone Forming Tumors
  • Osteoma
  • Osteoid Osteoma
  • Osteoblastoma

 

2. Cartilage forming Tumors
  • Chondroma
  • Osteochondroma
  • Chondroblastoma
  • Chondromyxoid fibroma
3. Giant Cell Tumor 6. Tumor like conditions
  • Solitary bone cyst
  • Aneurysmal bone cyst
  • Metaphyseal fibrous defect
  • Fibrous dysphasia
  • Osteofibrous Dysplasia
  • Myositis ossificans
  • Brown tumor of hyperparathyrodisim
  • Intraosseous epidermis cyst
  • Giant cell ( reparative ) granuloma
4. Benign vascular tumors
  • Hemangioma
  • Lymphangioma
  • Glomus tumor
  • Eosinophilic granuloma
5. Other benign connective tissue tumors
  • Desmoplastic fibroma  
  • Fibrous histiocytoma
  • Lipoma
  • Neurilemoma
  • Neurofibroma

Table 2. WHO’s classification of Benign Tumors.

 

Staging : Enneking has developed a useful staging system for benign and malignant tumors based on their pathologic observations see ( Table 3).

Stage        Description

1                 latent

2                 Active

3                 Aggressive

Table 3. Enneking’s Staging System

 

Surgical Margins: The margins of resection in the surgery on bone tumors can be (a) intralesional (b) marginal (c) wide (d) Radical.

Curettage : Over the past 20 years, incremental advances occurred that has improved the curettage through the use of burrs, adjuvant agents to extend the tumor kill and filling agents especially Allograft to fill large cavities instead of or in addition to Autograft

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Fig 1a: Tumor resection Margin                                 Fig 1b: Curetting of the tumor site

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Fig 1c: Burring of the resected tumor site                    Fig 1d: Lavaging with Adjuvants & curetting

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Fig 1e: Insertion of Allograft or bone substitute

and bone cements. Before carrying out the process of curettage, four things should be made clear 1) The stage of tumor. 2) Location of tumor 3) The need for adjuvant treatment and 4) The need for filling the defect and internal fixation. The important steps to curettage are a) Creating bone window as large as the lesion. Small windows in the bone often lead to poor visualization and mechanical instability to remove the tumors from around the corners. Use of b) The burr should go the subchondral bone in epiphyseal lesions such as a giant cell tumor, across to the opposite cortex and must remove 1 to 2 cm of cancellous bone in all directions c) Protection of the soft tissue from mechanical damage and tumor contamination during the operation d) Thorugh Irrigation of the cavity and repeat burring e) Use of adjuvants. A number of other adjuvants are available that produce either chemical or thermal injury to cells like hydrogen peroxide and alcohol. The most commonly used adjuvant is phenol. It should be applied to the curreted defects with cotton tipped applicators. The cavity should be then washed with alcohol, which helps dissolve the phenol and perhaps also may have an adverse chemical effect on tumor cells. It is generally thought that the use of phenol combined with aggressive curettage lowers the recurrence rate in the treatment of benign lesions, particularly giant cell tumors28,146 Allografting. (Fig 1a-1e)

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Fig 2a: Gaint cell tumor distal femur                Fig 2b: Operative field with tumore resected

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Fig 2c: Osteoarticular allograft fixed with IM Nail.                             Fig 2d: Post Operative 1 year

 

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Fig 3a: Anseumeral Bone Cyst Distal Femur     Fig 3b:ABC lesion specimen               Fig 3c: Osteoarticulating Allograft plated.

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Fig 4a: Pre-op X-ray shoulder of shoulder with Gaint Cell Tumor     Fig 4b: View of lesion                                     

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Fig 4c: Lesion resected                              Fig 4d: Osteoarticular allograft plated                   Fig 4e: Post-Op after 1 year

We have recently reviewed our study of Benign tumor of bone. The study consisted of 1) 108 patients from 1987 - 1997 of giant cell tumor as the most common of the benign tumor, consisted of Humorous, elbow, radius, metacarpal, proximal phalanx, pelvic, femur and tibia. All the Giant cell tumor were of stage 2 or 3. The maximum incidence of this tumor was in the condylar region of femurwith 41 % followed by above the knee 28 %. The protocol for the surgery in addition to the details as above, consisted of resection + deep frozen bone Allograft + internal fixation in 93 cases and resection + freeze dried Allograft in 15 cases. The study showed satisfactory function (good or excellent) in 87% of cases. Joint instability in 95 %, infection in 5 % , non-union in 3 % and fractures in 5 %. The failure rate in this series as judged by the need to remove the Allograft was 7 %. Our series did not get much opportunity to study the suitability of Allograft-prosthesis composite replacement combination in the proximal femur as the cases were very limited in number. It was interesting to note that the joint space remained well preserved radiologically in all but 5 Patients. This suggested that fresh articular cartilage remained viable and functional after allotransplantation. 2 ) The other forms of benign tumors as encountered and treated in our study series were totaling 59 in numbers. The most common of them was Fibrous Dysplasia composing 24 % followed by Aneurysmal Bone Cyst (ABC) composing 10 % of the total rest of tumors. High incidence of Fibrous Dysplasia was found in femur and tibia both 36 % each followed by ABC in the femur with 86 %. All the cases of fibrous Dysplasia were of stage 3. Radiation was avoided in all the cases of Fibrous Dysplasia as it is believed to be associated with development of malignant transformation. The method of treatment consisted of Curettage + freeze dried bone Allograft + internal fixation in 64 % cases and curettage + deep frozen + internal fixation in 36 % cases. In the ABC 86 % cases were of femur with 14 % case in Humorous. All the cases of ABC were of stage 3. Radiation therapy was employed at the range of 3000 and 4000 cGy29. The method of treatment employed in this type of tumor was curettage + Deep frozen bone Allograft + internal fixation in 72 % cases and curettage + Freeze dried bone Allograft + internal fixation in 28 % cases. The study in the 2nd series showed an overall satisfactory function ( good or excellent ) of in 85 % of cases. Joint instability in 3.4 %, infection in 5 % , non-union in 1.7 % and fractures in 3.4 %. The failure rate in this series as judged by the need to remove the Allograft was 7.3 %. Thus the overall conclusion from these study suggest that use of Allograft has a long way to go and it needs more and more practice to precise the desired results. (fig 2a-2d, 3a-3c, 4a-4e)

 

MALIGNANT BONE TUMORS

Common Malignant Bone tumors are as below:

1. Osteosarcoma: Osteosarcoma is a primary tumor of mesenchymal origin in which the proliferating cellular stroma directly produces an immature neoplastic bone matrix. Osteosarcoma compromises 20 % to 22 % of all primary malignancies of the bone and is the most common primary malignancies of bone in children, approx. 70 % to 75 % of cases occur between the age of 10 and 25 years Mirra102. They demonstrate an overall male predominance in gender predilection with the male female ratio varying from : 1.3 : 1 to 1.7 : 1 147. Osteosarcoma have been reported in virtually every site of the skeleton but the long tubular bones of the extremities are the most common anatomic location.

2. Chondrosarcoma : The term Chondrosarcoma is used to describe a heterogeneous group of neoplasms of mesenchymal origin that consist of well developed cartilage as the basic of neoplastic tissue. They usually occur in bone but sometimes are found in the soft tissues also. Chondrosarcoma account for about 10 % of all primary tumors of the bone. The age distribution for Chondrosarcoma is broad and varies from 16 months to 81 years and have a slight male predominance. They have a male to female ratio of 1.4 to 1 on average95,100. Chondrosarcoma occur more in bone performed in cartilage, the predominant number of cases occur about the trunk, hip girdle and shoulder girdle. The most frequent location is the femur 20 % 100.

3. Ewing's Sarcoma: Ewing's Sarcoma is a high grade malignant round cell neoplasm for uncertain histogenesis that originates primary in the bone and perhaps less commonly in soft tissue. It is a rare tumor and is the second most common primary malignancies of bone in children and adolescents, next to Osteosarcoma and is most common in the first decade of life57. Ewing’s Sarcoma comprises of 10 % of primary malignant bone tumor 108. It occurs in the first three decades of life with approximately 75 % to 80 % cases occurring between the ages of 5 and 25 years and has male predominance. Ewing's sarcoma occurs in almost every skeletal site, with the most favored location being the long tubular bones ( 50 % to 55 % ).

Application of Allograft in Malignant Bone Tumor

Proximal Humorus: Sarcomas of the proximal humerus are most likely to involve the axillary nerve as it passes adjacent to the inferior aspect of the humeral neck just distal to the joint. The auxiliary nerve has to be almost always sacrificed when the proximal Humorous is resected. Because the auxiliary nerve supplies the deltoid muscle and when the axillary nerve is sacrificed there is little advantage in retaining the deltoid and they should be resected together unless there is no oncologic advantage of doing so. A type 1 resection of the system suggested by Malwer101 is used for the removal of the proximal humerus with or without the deltoid. This is resection of choice for all the sarcomas of the proximal humerus that have not invaded the shoulder joint. Anterior resection of the proximal humerus is performed. The pectoralis is transected leaving a cuff of muscle on the humerus. The brachial vessels, median nerve and ulnar nerve are retracted medially. If the deltoid is resected with the specimen, a skin flap is developed over the deltoid. If the deltoid is saved, it is released from the clavicle, acromion and retracted from the proximal humerus and shoulder. An appropriate size proximal humerus Allograft which was chosen before with the side of a radiograph of the uninvolved side. However it should be taken care that the dia of the humeral head to be placed should correspond to a maximum 1cm tolerance with the dia of the head of humerus to be replaced. This will allow for smooth and pain free articulation without any locking effect. After the tumor has been removed, the Osteoarticular Allograft is opened from the sterile packing inside the operating room. It is dipped into a warm saline or Ringer's solution and 500mg/l of first generation of cephalosporin is added to it101. The soft tissues except the insertion of the rotator and shoulder capsule are removed and the Allograft cut to the required length. The fatty marrow is removed. A trial is done and if everything goes all right then the internal fixation is carried out. Otherwise the necessary adjustments in the length of the Allograft is made so as to accommodate it fitting. Once this is achieved a Broad Dynamic Compression plate for adults or a Narrow Dynamic Compression plate in a range of 6 to 8 holes for children and 8 to 10 holes for adults is placed across the Osteosynthesis site on the lateral aspect of the humerus. The plate is then fixed with screws accordingly on the Allograft portion only. Only one screw is put under compression at the junction of the bone with the Allograft and is subsequently removed once the Glenoid repair takes place so that the free Allograft will provide with a better mechanical leverage to work inside the depths of the Glenoid without much difficulty. The shoulder capsule, rotator cuff and subcapularis are repaired. The Allograft is held in position of maximal abduction. The rotator cuff is repaired tightly with interrupted nonabsorable zero sutures. The subcapularis is repaired anteriorly and the remainder of the joint capsule on the Allograft is attached to the patients capsule. Once this has been accomplished the Allograft is supposed to stay located within the Glenoid in a fully abducted position without held by the surgeon. Now the Allograft is brought into contact with the intact part of the resected Humorous and the single dynamic screw is once again inserted to its place. This guides the direction of the reduction and the remaining screws are easily put into the remaining holes of the plate. The wound is closed with proper drainage usually two (fig 5a-5f).

In our series of tumor study 3 patients (Osteosarcoma) had undergone Osteoarticular reconstruction of the proximal humerus with the technique as mentioned above and 2 patients (Chondrosarcoma) had Intercallary Allograft reconstruction with the protocol of the surgery as already described in the previous chapters. All the resections were of type 1101 type. All the Allograft were deep frozen. The average follow up had been 5 years. All the Allograft were fixed with internal fixation of Dynamic Compression plates and screws. All the patients are doing fine with only one developed minor complications which were taken care of. The results were very good to excellent. However we would caution that it is too early to arrive at the conclusion that it is the golden standard. We would suggest more studies on this subject to achieve better comparison of Allograft with other substitutes in this area of the skeleton.

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Fig 5a: Malawar’s classification for Humeral resection                      Fig 5b: Pre-op Osteosarcoma of humerus

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Fig 5c: Surgical margin       Fig 5d: Lesion Resected from site.           Fig 5e: Osteoarticular allograft plated

 

PELVIS

Bone tumors arising in the pelvis present particular difficulties in both Diagnosis and treatment156. The large internal capacity of the pelvis often permits tumors to grow to substantial size prior to Diagnosis and all too frequently the early symptoms of a deep seated pelvic tumor are misinterpreted as sciatic or degenerative lumbar spine pain and by the time a primary or secondary tumor is eventually diagnosed in the pelvis, a variety of factors make the appropriate treatment more difficult. Before the 1970's, most tumors arising from the bony pelvis were surgically treated with a hindquarter amputation ( Hemipelvectomy ) 83. After assessing the history , physical examination and simple laboratory & radiographic investigations of the patient, the surgeon should be able to make out the etiology of the pelvic lesion. If there is a history of primary tumor or if it is identified during initial examination, then there is no need for a diagnostic biopsy. If however no primary carcinoma is identified in the radiographic changes in the pelvis are similar to a primary bone tumor, then biopsy should be carried out, but first local systematic radiographic staging and CT or MRI should be carried out. To carry on with the biopsy the surgeon should first divide the bony pelvis into safe and unsafe zones for an open biopsy. Lesions of the Ilium, supra-acetabular region, sacrum or the medial portions of the superior/inferior ramification can be biopsied through a straight forward open procedure. Many of the biopsies of pelvic lesions can be done through the subperiosteal iliac wing approach. Sacral lesions should always be biopsied through a posterior approach. The anterior pelvis can be reached through the transverse incision that can be later shaped to an ilionguinal excision. Pelvic resections of the Enneking's system have been adopted by the Musculoskeletal Tumor Society which is described as type I( iliac), type II (Periacetabular), type III (obutrator)52 (fig 6a). Tumors that require acetabular resection (Enneking type II) present one of the most difficult reconstruction challenges in oncologic orthopedic. Bell8 have reported a success rate of 87 % with local recurrence in 17 % and have suggested that preservation of the limb and reconstruction with an Allograft may be considered as an alternative to hindquarter amputations in carefully selected patients who have bone sarcoma involving the Acetabulam. However patients who have high grade bone sarcomas must be warned that there is a substantial risk of local recurrence or infections. The standard incision for osseous pelvic resection is the extended ilionguinal incision which extends from the pubic tubernacle along the Inguinal ligament to the anterior superior spine and along the iliac crest to the posterior superior iliac spine. The posterior iliac resection (type I) needs more dissection and exposure posteriorly and may require extension of the posterior incision to the midline of the spine with or without a perpendicular midline extension. The posterior osteotomy is usually made through or adjacent to the sacroiliac joint. Adequate exposure of the external aspect of the Ilium is made by dissecting the gluteal musculature off of the external cortex of the Ilium by extensive detachment and retraction process. A large osteotome is used for the bony cut by either inside out or outside in depending on the size of the tumor. The type I resection leaves a bony iliac defect from the sacroiliac joint to the supra-acetabular Ilium and therefore a hip Arthoplasty reconstruction is not required. The bone defect is reconstructed with a pelvic Ilium Allograft and internal fixation with 4.5mm dia reconstruction plates and 4.5mm dia cancellous screws. We had come across one case of pelvic tumor ( Chondrosarcoma of the Ilium ) type I of Enneking classification which was treated with resection and reconstruction with pelvic Ilium Allograft and internal fixation with plates and screws. We had experienced only one patient in this category. The follow up has been for 4 years. Except for some minor infection (which was locally treated) no other complication has arised till now. (fig 6b-6d)

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Fig 6a: Enneking’s classification for pelvic resection                Fig 6b: Pre-op Osteosarcoma of the Pelvis                        

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Fig 6c: Lesion Specimen removed                Fig 6d: Sizing of lesion with allograft                Fig 6e: Po-op after 2 years.

FEMUR :

The distal femur is the single most common location for all bone tumors and is also the most commonly resected major bone where most experience has been gained in the study of limb salvage. Simon and associates reported the combined experience of members of the Musculoskeletal Tumor Society in their management of Osteosarcoma in the distal femur112. Over the last 15 years the trend has been to do more limb salvaging resections for Osteosarcoma and other bone tumors. The use of CT Scan, MRI and preoperative chemotherapy has reduced to a great extent the temptation of amputation for this problem. Tumors that arise from the distal femur and extends into the extraosseous tissues usually do not involve the politeal vessels or sciatic nerve unless they are exceptionally large. The biopsy incision should be anterior just medial or lateral to the rectus femoris muscle and proximal to the suprapatellar pouch. The joint must not be entered. The dissection should be direct to the lesion and perpendicular to the skin. When the incision is more on the lateral side the biopsy incision should be more lateral to the rectus femoralis and when the incision is more to the medial side the biopsy incision should be medial. If there is no anterior compartment to the tumor, still the biopsy should be done from the anterior approach an exception of this is when the tumor is a juxtacortical or surface tumor off the posterior surface148. Distal femur that require a resection of the articular surface can be safely removed with a resection through the joint. This is called an intra articular resection of the distal femur. The incision is made perpendicular to the skin and goes deep into the rectus femoris. The rectus femoralis is spared. The knee joint is opened and the joint fluid is inspected and if blood or hemosiderin is found there then it indicates that the tumor is in the joint and an extra-articular resection should be done otherwise carry out with the intra-articular procedure. The lateral tensor fascia and fascial attachment posterior to the vastus medialis is released from the femur. The knee is flexed to 90? and the medial head of gastrocnemius is identified and transected, leaving its origin attached to the femur. The popliteal artery and vein are dissected proximally to the adductor canal and the adductor magnus is released from the adductor canal. The peroneal nerve is retracted with the long head of the biceps. The knee ligaments are transected and the medial & lateral collateral's are divided perpendicular to the line of the meniscus. The posterior capsule is divided and the finally the distal femur is osteotomized. Curetting the medullary canal is very important at this stage to ensure that no tumor is left over there. The defect created by the distal femur is reconstructed using a distal femoral Osteoarticular Allograft, the side and size of which is already predetermined radiologically. The key to success here is in maintaining the limb length. The sterile Allograft is opened and it goes through the process of culture as described before. All the soft tissues and the fatty marrow in the medullary canal is removed. The surgical margins are determined and the Allograft is brought for the first trial. If any shortening to the Allograft is to be done it is done here keeping in mind to keep a bit of more length always in hand. Osteosynthesis site is trimmed. The Allograft is seated in the normal position and a 10 holes broad Dynamic Compression plate is taken, contoured and placed over the Allograft ensuring that it is equally distributed over the host bone and the Allograft. The holes on the side of the Allograft are fixed. Only one hole on the side of the host bone is drilled and tapped without inserting the screw into it. The capsule and ligaments are repaired keeping in mind that the knee can be extended to within 5? of full extension. Once the knee capsule and ligaments are repaired, the Osteosynthesis site is reduced and the previously drilled hole in the host bone is fixed with a screw. This will ensure the alignment of the Allograft with the host femur. The remaining screws are also now tightened to the host bone. The wound is irrigated and sutured with 2 drains.(fig a-fig 7f)

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Fig 7a: Pre-op Chondrosarcoma Femur          Fig 7b: Exposure of lesion        Fig 7c: Operative field after resection of lesion

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Fig 7d: Whole femur Osteocondylar bone allograft           Fig 7e: Allograft trail          Fig 7f: Post-op after 1year

The second type of Allograft reconstruction application in the femur is Intercallary Allograft in the diaphysis region of the femur. The Staging, Biopsy and other clinical evaluation procedures are the same as described before. It is important to determine per-operatively that the tumor has not affected the joint surface. The key to success here also is maintaining the limb length. The size of the Allograft to be used must be pre-determined with the help of the radiographs and it is always better to have a slight bigger Allograft in hand so that you can trim it afterwards. Once the tumor has been removed and the lavaging has been done the Allograft is cultured in the same manner as stated above. The Allograft is now placed in situ and the reduction is noted if everything is all right, we proceed with the fixation of the Allograft with the host bone. Here two techniques can be employed, the first and the most preferred one, being intramedullary interlocking nailing as it has superior stability in addition to maintaining the Allograft segment integrity. The second technique is internal fixation with the help of plates and screws. The type of fixation is the surgeons choice as to which he is at more ease and can accomplish the job easily and perfectly. We routinely use plates & screws both proximally and distally at the host Allograft junction .

The third Allograft application in femur is Osteoarticular proximal femur Allograft to reconstruct the proximal femur. The staging, radiographic and other clinical considerations should be thoroughly studied and biopsy be done through the lateral approach. The resection process starts with the patient in the lateral position. The incision is 6 inches proximally and distally lateral from the tip of the greater Trochanter. The incision is made deep and the capsule is released circumfrentially. At this stage, before the hip is dislocated, femur is osteotomized, so that it is easy to manipulate the proximal femur. The soft tissue need to removed as per the need that arises on physical evaluation. The superficial femoral vessels and the profound vessels are spared and the specimen is removed from the operative field. The site is completely lavaged as per the protocol mentioned earlier. The head dia of the resected host femoral head is measured and a same size Proximal femoral Osteoarticular Allograft is opened from the sterile pack. it is always advisable to enter into the operating room with atleast 3 sizes of Proximal femoral Allograft ( i.e. one size up and one size down so that there is no problem with the size of the femoral head after physical evaluation since a small size will easily dislocate and a bigger size will not fit at all or will get locked ). The selected Allograft is now cultured following the same protocol as described above. Once this is done the Allograft is brought and put in for a trial reduction inside the Acetabulam. If everything is all right then we go for the fixation of the Allograft otherwise we adjust the length discrepancy till the time that the reduction is perfect. All the soft tissue is removed from the Allograft except the abductor tendon and capsule of the hip joint. The host bone is cut to the same length so as to have the reduction smooth. A long Broad Dynamic Compression Plate is which can have atleast 6 holes on each side of the Osteosynthesis margin is taken, contoured and fixed on the Allograft side first with the same technique as stated before. The abductor tendon and the capsule is sutured, the site is thoroughly irrigated, sutured and drained with two tubes.

Our series of study over a period of 13 years involving bone tumors in femur consisted of 33 patients. All the Allograft used were deep frozen. The average period of follow up was 8 years. The maximum incidence of tumor was found in the distal femur with 78 % (male 69 %, female 31 %) followed by proximal femur 13% (male 75%, female 25 %) and lastly the diaphysis with 9% ( male 66.66%, female 33.33% ). Out of the total tumor types, Osteosarcoma was the highest with incidence rate of 94 % followed by Chondrosarcoma 3 % and Malignant fibrous histiocytoma 3 %. The results were as follows: infection 10 % ( which was controlled easily ), recurrence 6 %. The study showed satisfactory function of the joint (good or excellent) in 91 % of cases. Joint instability in 9 % and fractures in 15 %. The failure rate in this series as judged by the need to remove the Allograft was 6 %. Our series did not get much opportunity to study the suitability of Allograft-prosthesis composite replacement combination in the proximal femur as we did not get any case. We conclude that our results with the Osteoarticular Allograft had been gratifying. The results of the study showed lower complication and it is clear that this procedure, one of the many modalities available for reconstruction at this anatomic site. Although the current results are satisfactory but we intend to carry on the research at improving and seeing their viability in a long series of cases.

TIBIA

Approximately 10 % of primary sarcomas of bone occur in the tibia and the site is next to femur43. The most common malignant neoplasm in this site is Osteosarcoma. Limb salvage surgery in tibia is more difficult than any other anatomical site. To go ahead with the Allograft reconstruction surgery in tibia, the anatomic consideration of this region should be thoroughly kept in mind. We will go ahead with the process of reconstruction surgery in the proximal tibia. The same general principles of biopsy of any potential sarcoma apply to the lesions of the proximal tibia also. Assessment of staging studies i.e. plain radiographs, radionuclide bone scan and MRI should be done to determine the location and extent of destruction with respect to the joint surface. The biopsy incision is small, longitudinal, below the tibial tuberosity on the anteromedial side of the tibia or below the medial flare. We continue with the intra-articular Proximal resection only when confirmed that the joint has not been invaded by the tumor. The incision is started from the site of the biopsy incision and is extended proximal until the joint capsule has been opened from just proximal to the superior pole of the patella to the infrapatelar fat pad just medial to the patellar tendon. This inferior skin incision is extended down to 5 cm below where the osteotomy is planned. The patella length is measured and then the patella tendon and the medial & lateral collateral's are transected. Depending on site of the tumor's extraosseous component, the proximal fibula may or may not be resected. If the proximal fibula is saved the lateral collateral is retained otherwise the whole of proximal fibula be resected and the lateral collateral is transected. Flexing the knee the soleus muscle is released from its origin on the proximal tibia just distal to the lower border of the popliteus. At this point the posterior neurovascular bundles are visualized and the proximal tibia is osteotomized. The bone is transacted 1 cm below the tumor level and the distal tibial medullary canal is curetted. The Osteoarticular proximal tibial Allograft is opened and after following the previously described protocol of culture is inserted into the site for the first trial. If any length has to be reduced is done at this point. Once the trial reduction is over the Allograft is reduced and a 8 to 12 hole broad Dynamic Compression Plate is fixed laterally. The screws are first fixed on the Allograft with one screw only in dynamic position at the juncture of the host bone and Allograft. This screw is then removed and the free end of the Allograft is proceeded for ligament reconstruction. with the knee and the Allograft in a flexed position reduction , zero nonabsorable sutures are used for to reconstruct the capsule and the ligaments . Once the soft tissue reconstruction is over the remaining hole of the plate are fixed with screws on the host bone. Long term results of proximal tibial Osteoarticular Allograft have been reported33.

In our series of study of tumor in the last 10 years we had 22 cases of tumors of tibia. of these 21 cases were of Proximal tibial Osteosarcoma and 1 case of malignant fibrous histiocytoma. All the patients were treated with Osteoarticular proximal tibial Allograft. The results were are follows: infection 9 % ( which was controlled easily ), recurrence 4.5 %. The study showed satisfactory function of the joint ( good or excellent ) in 91 % of cases. Joint instability in 9 % and fractures in 13.6 %. The failure rate in this series as judged by the need to remove the Allograft was 4.5 %. The high fracture rate is related to the long term follow-up time and shows that these massive Allograft remain susceptible to fractures like the normal bone. It was noted that the joint space remained well preserved in all the patient thus showing that fresh articular cartilage remains viable and functional after allotransplantation. The study encourage us to incorporate this method of treatment in our routine treatment of malignant bone tumors in the proximal tibia.

Conclusion : Our series of malignant tumor study over the past 13 years encountering a total of 67 cases has shown that the occurrence of tumor was the most in Femur 49 %, followed by tibia 35 %, Humorous 8%, Radius 3 % and pelvis 5 %. The most common type of bone tumor was Osteosarcoma with 86 % followed by Chondrosarcoma 6 %, Malignant Fibrous histiocytoma 6% and fibrosarcoma 2 %. The study showed an overall satisfactory function of the joint ( good or excellent ) in 91 % of cases. Joint instability in 9 % and fractures in 14 %. Complications were infection 7.5%, Lung metastasis 12 % in which 6 patients died and two are doing fine, overall reoccurrence of tumor 7.5 %. The failure rate in this series as judged by the need to remove the Allograft was 6 %. We therefore conclude with the results of this study that osetoarticular Allograft can be used routinely in the treatment of malignant tumors . (Fig 8a-8d, 9a-9c)

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Fig 8a: Pre-op Osteosarcoma of tibia      Fig 8b: Lesion Specimen after resection      Fig 8c: Lesion being replaced with allograft

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Fig 8d: Plating of allograft to tibia

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Fig 9a: Fibrous Dysplasia of Tibia Fig         Fig 9b: Allograft being plated       9c: After 1.5 years

 

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