Bone Sarcoma in the Upper Extremity: Treatment Options Using Limb Salvage or Amputation
Extremity bone sarcomas are rare and pose a challenging problem for patients and their physicians. Physicians who treat bone cancer are called orthopaedic oncologists.
Osteosarcoma is the most common primary bone malignancy that is considered for limb salvage, although there are other types of bone cancer. The National Cancer Institute provides comprehensive information on bone cancer. There are approximately 500 and 1,000 osteosarcomas diagnosed in the United States per year. The majority of these bone cancers occur in the adolescent age group. A smaller number are present in children under the age of 10, and some develop in older people secondary to a pre-existing condition such as Paget's disease.
In the past, extremity bone cancers were treated by amputation with relatively poor functional outcomes. Over the last 30 years, limb salvage (operations to save the limb rather than amputate) has evolved. This technique has been proven safe and effective in most cases.
There have been developments in several areas to improve the outcomes with limb preservation. Adjuvant or "assisted" chemotherapy is now used for most bone sarcomas. Chemotherapy causes tumor necrosis, which allows for safer removal. In addition, chemotherapy causes the tumor to develop a rind or margin and in some cases shrink, helping the surgeon to completely resect the tumor and minimize the removal of normal tissue.
Imaging also plays a major role in limb salvage. With the development of radiographic studies such as magnetic resonance imaging (MRI), the surgeon can better see the extent of the cancer and plan the resection more precisely. The American Cancer Society provides more information on use of imaging tests to detect bone cancer.
Finally, there have been major developments in limb reconstruction. Surgeons now have available implants that can be matched to the patient's size, stronger metals, bone and soft tissue allografts (transplants), microvascular and muscle transfer procedures, and bone graft substitutes. These techniques allow the limb to be restored with good function.
There are even devices that can be expanded or "grown" for children to account for normal skeletal growth lost with limb preservation.
Despite all of these improvements and the enthusiasm for limb salvage, it is not for everyone. There are contraindications and complications that need to be considered. The decision needs to be made by the patient after a detailed and lengthy discussion with their cancer surgeon. The patient needs to have a thorough understanding of the advantages and disadvantages of limb salvage before pursuing this technique.
Anatomy and Pathophysiology
Although they are seen in all parts of the skeleton, most osteosarcomas are located near the knee joint and involve the lower femur and upper tibia. The tumor usually occurs in the metaphysis or diaphysis of long bones.
The tumor can invade and cross the growth plate. Osteosarcoma is an invasive cancer that usually extends out of the bone into the soft tissues. The tumor can involve the joint, muscles, nerves, and arteries near the bone of origin. As the tumor progresses, it destroys bone and may lead to fracture.
Hematogenous (through the blood) spreading of this cancer is a significant risk. Patients need to be staged for distant disease. The greatest risk is spread to the lungs. The cause of this malignancy is not known. There is no hereditary link for a standard osteosarcoma. Known environmental risk factors include radiation.
Progression of the Disease
Untreated osteosarcoma is rare. If left untreated, it will grow to an enormous size, destroying bone as it progresses. Pathologic fracture will inevitably occur, especially in weight-bearing bones. Osteosarcoma has a great propensity to spread to the lungs.
The presence of micro-metastatic disease at presentation is common and is one reason for chemotherapy. End-stage patients will develop extensive pulmonary disease, and osteosarcoma will metastasize to other skeletal and nonskeletal sites.
Nonoperative treatment for osteosarcoma is not reasonable, except for tumors located in anatomically inaccessible sites. An example is a large tumor of the spine. In this case, palliative (non-curative) radiation and chemotherapy can be given.
Even patients with demonstrated pulmonary metastatic disease are treated aggressively with chemotherapy and surgery. Some of these advanced-stage patients can be cured.
The optimal treatment of osteosarcoma requires some form of surgery. Radiation can be used for inoperable tumors, but is only palliative and generally not curative.
Current treatment for osteosarcoma uses neoadjuvant (preoperative) chemotherapy for approximately three months. The chemotherapy is given either through a vein (intravenous) or an artery (intra-arterial). Then, the patient is restaged both locally and systemically to see if the tumor has metastasized or changed in size. A decision regarding the type of surgery (limb salvage or amputation) is made.
The resected tumor is evaluated by a pathologist for the amount of necrosis. There is a direct relationship between necrosis (the percentage of dead tumor) and survival. Tumors that are 90 percent necrotic or better after chemotherapy have an excellent prognosis.
Chemotherapy alone is not enough to control the tumor in bone. Surgery is needed to remove the residual viable tumor cells. After surgery, patients are placed back on chemotherapy for up to one year. If pulmonary disease develops, the nodules can be removed surgically.
The first surgical decision concerns the feasibility of limb salvage. Most osteosarcomas (approximately 85 percent) are candidates for limb preservation.
There are some relative contraindications.
Large growing tumors that are poor responders to chemotherapy are often best managed by amputation.
Patients with tumors that infiltrate the skin around the bone are poor candidates to save the limb
Cancers that surround important nerves and arteries may need to be amputated.
Sarcomas in very young children are best managed by amputation. In these young patients, the limb length inequality after limb preservation will be excessive and de-functionalizing.
Any patient who must decide between amputation and limb salvage must understand everything involved with both options. A consultation with a prosthetist is invaluable in understanding life with amputation. They can usually show the patient and their family an example of the prosthesis they would have, and videos showing the activities that the patient could perform. Also, most cancer surgeons can arrange meetings for a patient deciding about surgery with another patient who has already had that type of surgery.
There are considerations in deciding between limb salvage and amputations.
- Emotional. Amputations can be both emotionally and physically devastating to patients.
- Technical. Unlike limb salvage, amputations tend to be technically less complicated operations for the surgeon, resulting in few complications.
- Ongoing surgery. Patients with amputations usually need no further surgery, while limb salvage patients may need multiple surgeries throughout their lives to fix problems that occur with the initial reconstruction.
- Return to Function. Amputation patients often have a faster return to function and may even have better function than limb salvage patients.
- Prosthetics. Artificial limbs have been improved in appearance and function. These limbs have endoskeletons (shells) that can be covered with a more natural appearing material to make them look more like a normal limb.
The joint mechanisms are also very sophisticated and can return the patient to a more normal gait. A patient with a below-the-knee amputation usually walks without a limp and can play most sports. Most observers would not even know the patient, in long pants, had an amputation.
Patients with above-the-knee amputations can also function very well. Although they often have a minimal limp and can play many sports, they tend not to function as well as below-the-knee patients because of the need for an artificial knee joint as part of the prosthesis.
Limb-girdle amputations such as a hind-quarter (through the hip joint) can be fitted, but function is limited. Amputations closer to the hip require more energy from the patient to walk than distal amputations.
Amputation patients in general require more energy to walk compared to limb salvage patients.
A unique amputation procedure, called the Van Ness procedure, is useful in very young children. The tibia, foot, and ankle can be preserved and fixed to the remaining femur after rotating it so the foot points backwards. The ankle joint then acts as the knee joint. These patients can be fitted as a below-knee amputee with better function than a standard above knee amputation. While this reconstruction always upsets the patient and their family when they initially hear about it, it is an excellent option, allowing these children to participate in almost all normal childhood activities.
Amputations of the shoulder, arm, or forearm have a poorer functional outcome than amputations of the thigh or lower leg. This is especially true for the shoulder girdle. The terminal device (artificial hand) of the prosthesis has only a limited ability to return manual strength and dexterity. Myo-electric prostheses may improve some of these deficiencies.
After a decision is made for limb salvage, there are two basic types of reconstruction in adults. Most osteosarcomas involve the knee joint, which needs to be removed during the resection.
The surgical reconstruction options include arthrodesis or arthroplasty.
Arthrodesis, or fusion, is a procedure that makes the joint permanently stiff. The knee joint will not bend. This can be accomplished with bone allografts, vascularized autografts, or a combination. Once the knee is fused solidly, it is a stable, durable reconstruction. It can withstand physical stress. Follow-up surgery is less likely with arthrodesis.
The disadvantages include:
- Loss of functions requiring the knee to bend, such as climbing or stooping.
- Arising from a chair is difficult, as is sitting anywhere that you need a bent knee, such as a movie theater or an airplane.
- Knee arthrodesis also places abnormal stresses on the joints above and below the knee, and can lead to future hip or back problems.
- Arthrodesis also increases the energy needed for the patient to walk.
Arthroplasty provides for a bendable knee. The procedure replaces the resected bone and joint. Arthroplasty can be accomplished with an allograft or a metallic implant. Allograft arthroplasty replaces the resected bone and joint with a bone transplant. These grafts are obtained from human donors and are frozen to diminish rejection problems. Freezing renders the bone dead and the cartilage can be kept minimally alive. The graft needs to heal to the host bone like a fracture. This healing can be impeded by the postoperative chemotherapy. Allografts can break or become arthritic, and the joint can be unstable. In the recent past, these arthroplasties were done with allografts alone, referred to as osteoarticular allografts (transplanted bone with its cartilage). These allograft reconstructions are now usually done by replacing the bone with an allograft, then replacing the cartilage with a total knee arthroplasty. This has an advantage of replacing the resected bone with bone rather than metal. This bone can be used for later reconstruction if the initial reconstruction breaks down, which happens often. The main disadvantage is problems with healing of the allograft to the patient bone.
Metallic arthroplasty is done with a modular oncology prosthesis. The modularity allows the surgeon to assemble the necessary bone replacement in the operating room to match the patient's size and the amount of bone resected. The device can be fixed to the bone with bone cement (methylmethacrylate) or the surgeon may use a press-fit porous stem that allows the bone to grow into the prosthesis to anchor it into the patient's body. The joint bearing is a rotating hinge. While the bearing has some freedom of movement, it is more constrained or hinged than a normal knee. This can lead to more problems than a standard total knee arthroplasty used in older adult patients. Problems can include loosening from the bone, wearing out of the parts, breakage of the parts, and stiffness. There is also some experience with a form of limb salvage for children using a "growing" or expandable prosthesis. The device can be lengthened as the child grows to keep up with growth of the opposite limb. These prostheses vary in their method of expansion from open surgical lengthening to magnetic expansion.
Limb salvage for tumors about the knee has two major steps: removal of the cancer and reconstruction.
Removal of the cancer
The first part of the procedure is the complete removal of the cancer with an adequate margin. The surgeon must be certain that the knee joint is not contaminated with tumor cells. If there is joint penetration, the joint is removed as one unit. The most reasonable reconstruction following this is a knee fusion. Most of the time, the joint can be opened and the distal femur or proximal tibia resected. Muscle covering the soft-tissue component of the tumor will be taken out to improve the margin. The nerves and arteries behind the bone are often identified and protected.
Before the procedure, the bone cut is determined based on the MRI. Once the cancer has been adequately removed, the specimen is opened to be certain the margins are adequate.
The next part of the procedure is reconstruction. If a modular oncology prosthesis is the desired reconstruction (most common), the femur bone is prepared by reaming the canal of the bone with a power instrument. The desired femoral stem diameter is selected.
The tibia is next prepared by removal of its cartilage surface and preparing the canal. The trial modular device is assembled and placed in the bone to check length, stability, and patellar tracking. The patella can be resurfaced as desired. The final modular oncology device can be inserted cemented or cementless. Cementless devices are porous-coated and bone ingrowth is necessary for success. This can be a problem in the presence of chemotherapy. The wound is closed in multiple layers. The ligaments do not need to be repaired because the rotating hinge bearing provides for joint stability. For tibial tumors, muscle flaps are necessary for closure and to repair the patellar ligament.
Allograft arthroplasty requires fixing the bone to the femur with a plate or rod. Rigid internal fixation is needed to promote healing. The allograft needs to be properly sized to match the bone and joint removed. All of the ligaments need to be sutured to the allograft to stabilize the joint. Instability is a significant problem with allograft arthroplasty.
Potential Operative Complications
In general there are more potential complications with limb salvage than with amputation.
- Recurrence. There is less risk of local recurrence with amputation. Survival for osteosarcoma, however, is the about the same whether the patient chooses limb salvage or amputation.
- Phantom pain after amputation
- Neuroma after amputation
- Wound necrosis
- Bone prominence
- Bone overgrowth in children. This results from the bone growth potential still present in children, and may require re-amputation to shorten the growing bone.
While troubling, phantom pain and neuroma usually can be managed with medication, and in some cases, a small surgical procedure.
The complications with modular oncology prosthetic arthroplasty are numerous but usually manageable.
- Infection. Infection is a serious problem that usually requires removal of the device before the infection can be cured.
- Wound necrosis. Wound necrosis can occur because of the extensive soft tissue dissection needed to remove the cancer. This problem can be minimized by the use of muscle flaps.
- Nerve palsy. Most of these operations require delicately separating the nerves from the tumor, which may lead to nerve palsy. The complication will usually resolve with time.
- Mechanical complications related to the prosthesis. The device can loosen or break, or the bearing (hinge) can fail. Wear of the bearing surfaces can lead to tissue reactions. Most mechanical complications can be minimized if the metallic device is used wisely. These implants are not made for functions such as running or impact athletics. Walking, biking, low impact dancing, and swimming are reasonable activities. Patients who are long-term cancer survivors will likely experience implant failure at some point in their futures.
After a lower limb amputation, the surgeon can place either a temporary prosthesis or a soft dressing. The temporary prosthesis allows earlier functional rehabilitation and is suited for an amputation at an above-the-knee level or distal. A prosthetist may be asked to place the cast pylon device on the limb in the operating room.
Physical therapy is started early for functional and psychological reasons. Therapy consists of gait training, joint mobilization, and muscle strengthening.
If a soft dressing is applied, patients are also taught how to wrap the limb to diminish swelling.
Prosthetic fabrication is usually held for about three months to allow the limb to regain its normal shape. After the leg is ready, the patient is taught how to use it. The higher the level of amputation, the more training is necessary. Patients with high level amputations may benefit from an inpatient stay at a rehabilitation center. Upper limb amputations need extensive rehabilitation by occupational and physical therapy. Prosthetic use is taught and the patient is instructed on how to use the opposite limb for activities of daily living.
Limb salvage with a modular oncology device also requires significant rehabilitation. Shortly after surgery, the patient will go to physical therapy for gait training, knee range of motion, and muscle strengthening.
If the device is placed without cement, partial weight-bearing ambulation is necessary for six weeks.
The soft tissue repair after limb salvage has a significant effect on rehabilitation. If a quadriceps reconstruction is performed, especially for proximal tibial tumors, this repair needs to heal before active exercise is started. This is usually at six weeks. Range of motion exercises are influenced by the patellar tracking and tightness of the knee.
Limb salvage with an allograft requires somewhat different rehabilitation. The allograft needs to be protected with a walking aid until healing occurs at the junction of the allograft and host bone.
Children especially need to be encouraged during the rehabilitation process. While they continue on chemotherapy, they have a diminished energy level and lack motivation to exercise. There is a strong tendency for children to develop a knee flexion contracture, and this needs to be avoided.
In general, patients with cemented modular oncology devices recover quicker than all other forms of limb salvage and amputation.
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