Journal of the American Academy of Orthopaedic Surgeons 56 Metastatic disease is the leading cause of death in cancer patients. Bone is the third most common site of metastatic disease, after lung and liver. Tumors of breast, thyroid, lung, prostate, and kidney origin are the most likely to metastasize to bone. Of the estimated 1.2 million new cases of cancer diagnosed, more than one half will be osteo- philic tumors (i.e., breast, lung and prostate cancer). 1 Furthermore, by the time of death, more than 50% of patients with these tumors will have had metastases to bone. Im- provements in oncologic manage- ment of patients with metastatic disease have resulted in increased duration of survival. As a result, orthopaedic surgeons are being asked more frequently to evaluate and treat the skeletal manifestations of metastatic disease. Virtually any primary malignant tumor can metastasize to bone, and any bone may be involved. How- ever, metastatic lesions most typi- cally occur in the spine, pelvis, femur, ribs and skull. In most cases, there are multiple sites of involve- ment. Large impending lesions or actual pathologic fractures often result in forced immobilization due to severe pain and account for as many as 60% of orthopaedic proce- dures performed on patients with metastatic disease. 2 Most femoral lesions involve the proximal third. However, this review will discuss the evaluation and treatment of metastatic disease in any portion of the femur. Clinical Presentation Pain is the most common present- ing symptom of metastatic disease (both solid tumors and hematologic malignant conditions). In a study of 87 patients with breast cancer, 32 of the 33 patients who had osseous metastases had bone pain. 3 In a study of 536 patients with multiple myeloma, bone pain was reported in more than two thirds. 4 Al- though the mechanism responsible for causing bone pain remains incompletely understood, it is thought to be the result of stretch- ing of the periosteum by increasing tumor size or stimulation of nerve endings in endosteal bone. The symptoms of metastases in the lower extremity range from a dull ache to a deep-seated, intense pain. Dr. Swanson is Resident, Department of Orthopaedic Surgery, Mayo Clinic, Rochester, Minn. Dr. Pritchard is Professor of Ortho- paedic Surgery and Consultant, Mayo Clinic, Rochester. Dr. Sim is Professor of Orthopaedic Surgery and Consultant, Mayo Clinic, Rochester. Reprint requests: Dr. Pritchard, Mayo Clinic, 200 First Street SW, Rochester, MN 55905. Copyright 2000 by the American Academy of Orthopaedic Surgeons. Abstract Nearly every malignant neoplasm has been described as having the capability to metastasize to bone. Of the estimated 1.2 million new cases of cancer diagnosed annually, more than 50% will eventually demonstrate skeletal metastasis. Advances in systemic and radiation therapy have led to a considerable improve- ment in the prognosis of patients with metastatic disease. As a result, orthopaedic surgeons are being asked with increasing frequency to evaluate and treat the manifestations of skeletal metastases. The femur is commonly the site of large impending lesions and complete pathologic fractures. Although the health status of some patients may preclude operative intervention, established pathologic fractures of the femur and metastatic lesions deemed likely to progress to imminent fracture generally should be treated surgically. A ratio- nal approach to selection of the proper treatment for these problems includes consideration of the patientÕs overall medical condition and the type, location, size, and extent of the tumor. Treatment principles are the same regardless of location. A construct should ideally provide enough stability to allow immedi- ate full weight bearing with enough durability to last the patientÕs expected life- time. All areas of weakened bone should be addressed at the time of surgery in anticipation of disease progression. To minimize disease progression and possi- ble implant or internal fixation failure, postoperative external-beam irradiation should be considered. J Am Acad Orthop Surg 2000;8:56-65 Surgical Treatment of Metastatic Disease of the Femur Kyle C. Swanson, MD, Douglas J. Pritchard, MD, and Franklin H. Sim, MD Kyle C. Swanson, MD, et al Vol 8, No 1, January/February 2000 57 Weight bearing may precipitate severe discomfort as a result of microscopic buckling. 5 Night pain and pain at rest are also cardinal features at presentation. A pathologic fracture, most com- monly of the femur, 6 may be the first presenting sign of metastatic disease. Approximately two thirds of all long-bone pathologic frac- tures occur in the femur. 7 Most (50%) involve the proximal femur, with 20% involving the intertro- chanteric region, and the remainder occurring in the subtrochanteric, diaphyseal, and supracondylar re- gions. The incidence of pathologic frac- ture of the femur is quite variable, depending on tumor type, location, and histologic characteristics. Breast cancer accounts for most pathologic fractures, but a large percentage of renal cell carcinomas and thyroid cancers cause pathologic fracture as well, due to the lytic nature of the bone involvement. In one study of 180 pathologic fractures in 157 patients, 130 fractures were sec- ondary to breast, lung, or prostate carcinoma. 8 Habermann et al 9 eval- uated 283 pathologic fractures and 23 impending fractures of the femur. Metastatic disease from four types of primary tumors accounted for 85% of the fractures (breast, 56%; kidney, 11%; multiple myeloma, 9.5%; lung, 8.5%). 9 Only 11 (3.6%) of the 306 pathologic and impend- ing fractures were due to prostate cancer. Although the incidence of prostate cancer is relatively high and its metastatic spread is almost universally to bone, it infrequently causes pathologic fracture. This may be related to its blastic, rather than lytic, nature. Clinical Evaluation Proper evaluation of a patient with metastatic disease begins with a thorough history and physical examination. For patients present- ing with no prior history of malig- nancy, salient historical points include characterization of pain, weight loss, and decline in activity level. Prior history of malignancy should heighten clinical suspicion. The location of the pain usually directs the physical examination, although metastases that involve joints or periarticular bone may pro- duce symptoms (referred pain) sim- ilar to those of arthritis. With in- volvement of the femur in the hip and thigh region, swelling and soft- tissue masses are rarely detectable. Laboratory evaluation is seldom diagnostic in the workup of meta- static disease because there is no single specific marker of bone metastasis. However, disturbances in normal metabolic and hemato- logic variables can aid in the diag- nosis of a primary or secondary disorder associated with a patho- logic process. Hypercalcemia is a common met- abolic complication of metastatic disease. In a study of 498 patients with breast cancer, hypercalcemia was noted in 86 patients (17%) on first recurrence in bone. Unrecognized, it can be the source of significant mor- bidity. Serum calcium levels be- tween 2.9 and 3.1 mmol/L (11.5 to 12 mg/dL) may cause unpleasant side effects related to dysfunction of the gastrointestinal tract, kidneys, and central nervous system. When calcium levels exceed 3.2 mmol/L (13 mg/dL), renal insufficiency and calcification in kidneys, skin, blood vessels, lungs, heart, and stomach may occur, particularly if blood phosphate levels are normal or ele- vated due to impaired renal func- tion. Severe hypercalcemia, usually defined as a calcium level of 3.7 mmol/L (15 mg/dL) or above, is a medical emergency. Death may ensue as a result of cardiac arrhyth- mias and renal failure. 10,11 When there is evidence of meta- static disease and no primary tu- mor has been identified, the patient should undergo biochemical screen- ing for multiple myeloma. This in- cludes a complete blood cell count, erythrocyte sedimentation rate, and serum protein electrophoresis. Approximately 70% of patients with multiple myeloma are anemic, and approximately 65% have an ele- vated sedimentation rate. 12 When adenocarcinoma is suspected, it may be reasonable to evaluate tu- mor markers, such as α-fetoprotein, β-human chorionic gonadotropin, carcinoembryonic antigen (associ- ated with ovarian and breast can- cer), and prostate-specific antigen. However, because of the lack of specificity, the value of these mark- ers generally resides in assessment of response to therapy, rather than identification of the primary site, in a patient with metastatic disease. Rougraff et al 13 have outlined a successful diagnostic strategy aimed at identification of the pri- mary malignant tumor in patients who have skeletal metastases of unknown origin. Evaluation con- sists of a history, physical examina- tion, routine laboratory analysis, plain radiography of the involved bone and the chest, whole-body technetium-99m bone scintigraphy, and computed tomography (CT) of the chest, abdomen, and pelvis. In 34 of their 40 patients (85%), the primary site was identified. Labo- ratory values were found to be nonspecific in all cases. The history and physical examination revealed the occult primary site of the malignant tumor in 3 patients (8%). Plain radiographs of the chest were diagnostic of lung carcinoma in 17 patients (43%). An additional 6 (15%) primary lung carcinomas were identified with CT of the chest. Computed tomography of the abdomen and pelvis estab- lished the diagnosis in 5 patients (13%). Although tissue biopsy alone was diagnostic in 3 patients (8%), it was not useful in identify- Surgical Treatment of Metastatic Disease of the Femur Journal of the American Academy of Orthopaedic Surgeons 58 ing the primary site of malignancy in 26 (65%) patients. Evaluation of skeletal metastases is usually accomplished with one or more of four clinical imaging meth- ods: plain-film radiography, radio- isotope scanning, CT, and magnetic resonance (MR) imaging. Radio- graphic evaluation should involve not only spot orthogonal views of the affected region but also a sur- vey with anteroposterior and lateral radiographs of the entire femur. Care must be taken to avoid miss- ing metachronous lesions, which may influence the choice of treat- ment and may ultimately compro- mise outcome. Metastatic lesions originating from the lung (Fig. 1), kidney, and thyroid are commonly lytic in ap- pearance. Lesions of prostatic ori- gin are usually blastic. Breast carci- nomas are commonly mixed in appearance. Most metastatic lesions arise from within the intramedullary canal. In rare instances, aggressive vascular tumors are intracortical, whereas squamous cell carcinoma of the lung may be juxtacortical. Bone lesions in patients more than 40 years old are more likely to be sec- ondary to metastatic lesions and myeloma, but bone lesions in patients less than 40 years old are more likely to be related to infection and primary tumors of bone. 14 Lod- wick 15 described three patterns of bone destruction: geographic le- sions (solitary, well-defined lesions with sharply demarcated borders, seen in the most slowly developing metastases), Òmoth-eatenÓ lesions (multiple small lytic areas in spongy and cortical bone with ill-defined margins), and permeative lesions (multiple tiny lytic areas in princi- pally cortical bone, found in the most aggressive lesions). Patients presenting for ortho- paedic evaluation of impending or pathologic fracture of the femur usually have a prior history of a malignant condition. If a patient has a history of skeletal or visceral metastasis and a lesion of the fe- mur consistent with metastatic dis- ease, rarely is a study other than high-quality orthogonal radiogra- phy of the entire femur necessary. However, in the case of lesions in either of the femoral condyles, the femoral head, or the acetabulum, CT may be necessary to assess the degree of bone destruction. Fur- thermore, if there is reason to eval- uate the amount of involvement of the femur or if it is suspected that a large soft-tissue mass may be asso- ciated with a bone lesion (as may occur in renal cell carcinoma or squamous cell carcinoma), MR im- aging may be helpful. One must be cautious about plain-film radiographic evaluation of a solitary osseous lesion consis- tent with metastatic disease in a pa- tient with a remote history of a prior malignant condition (>5 years) but without prior evidence of distant metastases. The possibility of a sec- ond primary tumor or even a sar- coma of bone or soft tissue should always be considered, especially if Figure 1 Anteroposterior (A) and lateral (B) radiographs of the knee reveal large destructive lesion of the distal femur due to metastatic disease originating in the lung. C and D, Radiographs obtained after prophylactic stabilization with a dynamic compression screwÐplate device augmented with methylmethacrylate. A B C D Kyle C. Swanson, MD, et al Vol 8, No 1, January/February 2000 59 the radiologic characteristics are not consistent with metastases from the primary tumor. Obtaining a biopsy prior to or at the time of surgery should be considered to confirm the diagnosis. Further imaging is warranted if there is a prior history of malignancy coupled with symptoms suggestive of metastatic disease, even when radiographs appear normal. Edel- styn et al 16 demonstrated that more than 50% of the medullary canal must be destroyed before a meta- static lesion is visualized on plain films. Radionuclide scanning with technetium-99m methylene diphos- phonate is an extremely sensitive modality for detecting skeletal lesions. A period of 2 to 18 months may be necessary before a lesion initially evident on radionuclide scanning becomes apparent on plain-film radiography. 17 The main disadvantage of bone scintig- raphy is its lack of specificity; find- ings must always be correlated with further imaging. Treatment Strategy General Considerations The management goals of treat- ment of metastatic disease of the femur are relief of pain and resto- ration of premorbid ambulatory function. Recognition of the full therapeutic potential for each patient requires a multidisciplinary team approach. The decision between operative and nonoperative management is determined on the basis of the loca- tion, tumor type, and extent of the tumor and the patientÕs general med- ical condition (Fig. 2). The initial step in a rational approach to im- pending or established pathologic fractures of the femur is to carefully examine the patient and to deter- mine the overall health status. If there is no reasonable expectation that the patient can survive a major operative procedure, nonsurgical measures may be the only viable alternative for palliation. If the patient can reasonably be expected to survive the procedure but will have an extremely limited potential for survival beyond a few weeks, it may not be prudent to proceed with an operative procedure. Patients who are not expected to survive long enough to recover and truly benefit from surgical treatment may decide against committing to the time, dis- comfort, and expense of proceeding with an operation and may instead prefer palliative measures, such as analgesic medications or splinting. Although the latter approach would probably restrict the patient to bed and chair, it might be appealing to someone who is aware of his or her short life expectancy. Pathologic Fracture If the patient is deemed to be healthy enough and the life expec- tancy is such that there will be suf- ficient benefit (e.g., pain relief, ease of mobility, ease of care) to justify the procedure, an operative ap- proach might be appropriate. After assessment of the general health status, the next step is to evaluate local tumor factors. If the patient has a pathologic fracture secondary to metastatic disease, local factors must be addressed when planning treatment. In most cases, the surgeon should concentrate on achieving stable fixa- tion (Figs. 1 and 3), with the expec- tation that local control of the metastatic disease can be obtained without resection of the tumor. This is true of most metastatic lesions, especially those due to primary tumors in the breast or prostate. However, some metastatic lesions are relatively resistant to adjunctive treatments, such as radiation therapy, chemotherapy, and hormonal ma- nipulation. For example, there are few chemotherapy options for hypernephromas, which are also particularly unresponsive to radia- tion therapy. In instances in which there is considerable bone destruc- tion, fracture fixation and postoper- ative radiation therapy do not ade- quately control the tumor, and Not a surgical candidate Palliative treatment Possible surgical candidate Impending fracture Low risk of fracture Palliative treatment High risk of fracture Established fracture General health status Resection or fixation ± adjuvant treatment Resection or fixation ± adjuvant treatment Figure 2 Treatment strategy for patients with metastatic disease of the femur. Surgical Treatment of Metastatic Disease of the Femur Journal of the American Academy of Orthopaedic Surgeons 60 tumor progression leads to ultimate failure of the fixation (Fig. 4). Be- cause patients with hypernephroma may have a relatively prolonged survival, particularly if there is only one site of metastatic disease, it may be better to resect the involved area of bone and perform a prosthetic reconstruction, rather than relying on internal fixation and adjuvant radiation treatment. In addition to dealing with the fracture, resection of a solitary metastasis may im- prove the patientÕs chances of sur- vival. This strategy is applicable to other tumors that are resistant to radiation therapy or are prone to recurrence. Preoperative emboliza- A B C D Figure 3 Anteroposterior radiographs of the femur demonstrate pathologic subtrochanteric fracture (A) and impending distal femur fracture (B). C and D, Anteroposterior radiographs obtained after stabilization with an intramedullary nail. A B C Figure 4 A, Anteroposterior radiograph of the proximal femur 2 years after intramedullary fixation of an impending pathologic fracture due to metastatic renal cell carcinoma. Despite radiation therapy, there was progression of the lesion with extensive cortical bone loss. B, Extensive vascularity of the lesion necessitated preoperative embolization. C, Anteroposterior radiograph obtained after proximal femoral replacement arthroplasty. Kyle C. Swanson, MD, et al Vol 8, No 1, January/February 2000 61 tion of highly vascular lesions may minimize the risk of massive hem- orrhage during surgery. The size and extent of the tumor are also important factors that must be carefully assessed when plan- ning an operative procedure. In ad- dition to plain radiography, MR imaging may provide helpful infor- mation regarding intramedullary involvement, as well as any soft- tissue extension of the tumor. A CT scan may reveal the extent of corti- cal disruption. Technetium scan- ning or MR imaging may suggest the possibility of additional lesions in the same bone. However, in the case of highly aggressive lesions or multiple myeloma, the Tc-99m bone scan may not be positive. Impending Pathologic Fracture If the patient is known to have metastasis to the femur but there is no actual fracture, the surgeon needs to assess the relative risk of fracture. The type, extent, size, and location of the tumor are all factors in determining the risk of fracture. Lytic lesions are more likely to frac- ture than blastic lesions. Large tumors, those that have soft-tissue extension, and those that occur in the region of the lesser trochanter of the femur are particularly prone to fracture. There have been several attempts to provide guidelines for assessing the risk of fracture in the presence of metastasis. 18-21 Although it must be borne in mind that estimating the risk of pathologic fracture is very subjective and is dependent on many variables (e.g., location of lesion, quality of host bone, and anticipated load), the Mirels scoring system has proved useful (Table 1). The location of the lesion, the degree of pain, the type of bone destruction, and the size of the defect are the variables considered in this 12-point scoring system. A score of 9 or above indicates a high likelihood of subsequent fracture. In addition to the Mirels system, several general rules regarding involvement of the femur may be helpful. Even small lesions in the region of the lesser trochanter are particularly at risk for fracture. Most lesions in the subtrochanteric area are also at high risk, especially when the metastasis is on the medial aspect of the bone. In diaphyseal lesions, destruction of 50% of the diameter or one cortex, as evi- denced radiographically, is proba- bly a valid predictor of subsequent fracture. Pain, particularly with weight bearing, in a lytic focus fol- lowing radiation therapy is a solid indication for prophylactic stabi- lization despite the radiographic appearance. Although there are guidelines and methods of systematic assess- ment, there is really no accurate way to predict the risk of fracture. Even experienced orthopaedic sur- geons will occasionally underesti- mate the risk of pathologic fracture. If there is a high risk of fracture and the patientÕs general condition warrants an operative approach, an appropriate procedure can be select- ed and planned. Preoperatively, the patient will need to protect the femur with ambulation aids to mini- mize the chance of a fracture occur- ring before the procedure. Preoperative Planning Metastatic lesions to the femur present unique challenges, but the treatment principles are the same regardless of location. A construct should ideally provide enough stability to allow immediate full weight bearing with enough durability to last the patientÕs expected lifetime. In addition, all areas of weakened bone should be ad- dressed at the time of the operation in anticipation of disease progres- sion. To minimize disease progres- sion and possible failure of the im- plant or internal fixation, radiation should be administered postopera- tively, preferably to the entire femur. Operative Procedures by Site Femoral Head and Neck Fractures Both impending lesions and complete pathologic fractures of the femoral head and neck should be managed with replacement ar- throplasty (Fig. 5). The high stresses across the proximal femur, com- bined with the limited potential for healing, even in low-demand pa- tients, has resulted in a high rate of failure for internal fixation devices. Moreover, fractures in tumor- destroyed bone in the femoral neck Table 1 Mirels Scoring System for Assesing Risk of Pathologic Fracture in Long Bones * Score Variable 1 2 3 Site Upper limb Lower limb Peritrochanteric Pain Mild Moderate Functional Lesion type Blastic Mixed Lytic Size (as a proportion <1/3 1/3 - 2/3 >2/3 of shaft diameter) * Reproduced with permission from Mirels H: Metastatic disease in long bones: A pro- posed scoring system for diagnosing impending pathologic fractures. Clin Orthop 1989;249:256-264. Surgical Treatment of Metastatic Disease of the Femur Journal of the American Academy of Orthopaedic Surgeons 62 (even nondisplaced fractures) will rarely heal within the patientÕs remaining life span. There have been several reports of favorable results with prosthetic replacement. 22,23 Lane et al 24 re- ported the results in 167 patients treated by endoprosthetic replace- ment for impending or complete pathologic fractures of the hip. All patients reported dramatic relief of pain. Use of a long-stemmed fe- moral endoprosthesis or a total prosthetic hip resulted in significant enhancement of the ambulatory sta- tus in three fourths of those who were able to walk before the frac- ture. Nonwalkers improved in their ability to transfer. The patients who had little benefit from the procedure were those who were bedridden, usually with severe metastatic in- volvement of the spine. Patients with proximal femoral lesions may have concurrent ace- tabular lesions. Harrington 25 has classified acetabular metastatic lesions into four groups on the basis of location, extent of involve- ment, and surgical technique re- quired to accomplish acetabular reconstruction. Unless tumor in- volvement is extensive, creating structural weakness in the acetabu- lum, a standard cemented bipolar hemiarthroplasty or hip replace- ment may be utilized. The choice of hemiarthroplasty versus total hip arthroplasty is dependent on the condition of the acetabular cartilage and the extent of involvement. Harrington 26 has reported a compli- cation rate of less than 1% for endo- prosthetic migration due to weak- ened periacetabular bone. In lesions that extend distally into the region of the lesser trochanter, a calcar-replacing prosthesis may be utilized. Multiple lesions in the peritrochanteric and diaphyseal regions of the femur, as well as rela- tively radiation therapyÐresistant lesions, are often best addressed with a long-stemmed prosthesis to prophylactically reinforce the fe- mur and avoid stress risers, espe- cially in patients with potentially long survival who are prone to multiple lesions, such as myeloma. Additionally, if there is thought to be significant risk that distal lesions will develop in the patientÕs re- maining life span despite radiation therapy, use of a long-stemmed prosthesis may be indicated. Intertrochanteric Fractures The surgical treatment of patho- logic intertrochanteric fractures remains controversial. Lesions con- fined to the intertrochanteric region, with minimal medial cortical-bone destruction, have traditionally been treated with a compression screw or nail plate. However, prolonged sur- vival, local disease progression, poor initial fixation, delayed union or nonunion, and lack of load shar- ing between the implant device and residual bone have all contributed to a high failure rate with this form of treatment (Fig. 6). Proponents of the use of open reduction and internal fixation with a compression screw or nail- plate device stress the importance of adjunctive stabilization with methylmethacrylate. A cortical window is created in the lateral cortex, and all devitalized tumor- laden tissue is removed. Whether the compression screw should be inserted before or after injection of methylmethacrylate into the bone is controversial. Some surgeons have chosen to hollow out the femoral head and neck by drilling to the subchondral bone. Cement of liquid consistency is then placed in the defect, and the compression screw is placed in the cement. Advocates argue that the screw is thus embedded in cement rather than in bone of questionable in- tegrity. The combination of screw threads and cement gives a greater Figure 5 A, Anteroposterior radiograph of the proximal femur shows a pathologic frac- ture of the femoral neck. B, Anteroposterior radiograph obtained after bipolar hemiarthro- plasty. A B Kyle C. Swanson, MD, et al Vol 8, No 1, January/February 2000 63 surface area of contact for the fixa- tion device in the femoral head and thus reduces the risk of the screw cutting out of the femoral head. Critics state that drilling of the femoral head may result in osteo- necrosis or release of microemboli of cement into the rich vascular plexus in the head of the femur. Adjunctive stabilization by inject- ing methylmethacrylate distally into the medullary canal can also add stability to the cortical screws along the side plate. The cortical screws are then inserted by drilling and tapping both the bone and the methylmethacrylate. Intramedullary hip screws have recently been used for pathologic intertrochanteric fractures. These devices have the biomechanical advantage of more medial place- ment closer to the compression side of the femur and away from the lateral-tension side. However, short intramedullary hip screws have been problematic because of fractures occurring at the tip of the nail in the diaphyseal region. Long intramedullary hip screws have the advantage of protecting the entire bone, but there have been few reports on their use. Another suc- cessful alternative includes the use of an intramedullary rod with proximal fixation screws that ex- tend into the femoral neck and head, with distal interlocking. Extensive involvement of the femoral head and neck with exten- sion into the trochanteric and sub- trochanteric regions is seldom managed successfully with internal fixation devices. Prosthetic replace- ment with either calcar or proximal femoral devices is the procedure of choice for large destructive areas not amenable to internal fixation, for salvage of failed internal fixa- tion, and for lesions not amenable to radiation therapy. Ease of appli- cation and improvements in im- plant design and availability have contributed to more frequent use of these devices. Potential disadvan- tages include increased rates of postoperative infection and disloca- tion. With use of proximal femurÐ replacing prostheses, loss of hip flexor and abductor strength re- sults in permanent gait distur- bance. Despite the high complica- tion rate, patients may be allowed immediate weight bearing with predictable relief of pain. Use of the bipolar femoral component and modular design has helped reduce the incidence of complications due to improper soft-tissue tension and dislocation. Subtrochanteric Fractures Subtrochanteric fractures are pri- marily treated with intramedullary devices. The region extending 5 cm distally from the lesser trochanter receives tremendous torque and shear stress, resulting in high rates of failure with screw and side-plate devices. The Zickel nail was previ- ously used to treat complete and impending pathologic fractures in the subtrochanteric region (Fig. 7). Its design allowed stable fixation between the proximal and distal fragments. Zickel and Mouradian 27 reported successful results in the treatment of 35 pathologic impend- ing and complete fractures in the subtrochanteric region. Early mobi- lization or ambulation was achieved in nearly all cases. Insertional difficulty, proximal fragment fracture, femoral shorten- ing, varus migration, and rotational instability associated with the Zickel nail have been addressed by the current use of reconstruction A B Figure 6 A, Anteroposterior radiograph of the proximal femur demonstrates a large destructive lesion of the peritrochanteric region stabilized with a compression screwÐplate device. B, Anteroposterior radiograph obtained 1 year after internal fixation shows pro- gressive collapse and failure of the internal fixation. Surgical Treatment of Metastatic Disease of the Femur Journal of the American Academy of Orthopaedic Surgeons 64 intramedullary nails (Fig. 3). Se- cure fixation may be obtained with two screws directed proximally into the femoral head. Likewise, the nail should be statically locked with two distal screws. Methyl- methacrylate can be used as an adjunct to fixation, but is not neces- sary in most cases, due to the in- trinsic strength of the device. Recently, so-called third-genera- tion variations of the reconstruc- tion nail have become available. A feature of these devices in common with early reconstruction-nail de- signs is the capability for proximal and distal interlocking. However, these devices differ primarily in the proximal interlocking device. The spiral-blade nail uses a single low- profile spiral-blade device to secure proximal fixation while conserving bone loss in the femoral neck. In many cases, these nails have been placed without reaming, thus di- minishing blood loss. The use of modular proximal femoral replacement prostheses should be reserved for radiation therapyÐresistant lesions with extensive involvement of the head, neck, and peritrochanteric femur for which stable proximal screw fixation is unattainable (Fig. 4). In selected patients with a solitary metastasis and overall favorable prognosis, reconstruction with an allograft-prosthetic composite may also be a consideration. There is no role for condylocephalic or Ender nails because of the high rate of mechanical failure. Diaphyseal Fractures Impending pathologic fractures of the femoral shaft can usually be treated by conventional closed in- tramedullary rodding techniques. The use of reconstruction nails, locked proximally and distally, has served to reduce the common com- plication of progressive femoral collapse with telescoping of the fracture fragments and proximal migration of the rod. With tumor progression, proximal placement of screws into the femoral head offers more secure fixation than conven- tional transverse or antegrade screw placement and may protect the femoral head from subsequent fracture. Open rodding techniques may be necessary for large defects with extensive cortical destruction. Exposure of the lesion, curettage, and augmentation of the lesion with methylmethacrylate may be necessary to prevent collapse. Distal Femur Fractures Pathologic fractures in the supra- condylar and condylar regions of the femur are unusual and difficult to treat. If there is sufficient bone stock, use of conventional internal fixation devices augmented with methylmethacrylate will usually achieve stability. Satisfactory pain relief and restoration of ambulatory function have been achieved with nail-plate and dynamic compression screwÐplate devices (Fig. 1). Use of the Zickel supracondylar nail has reportedly been a successful treat- ment option for fractures in the supracondylar region. 28 Treatment with internal fixation devices is gen- erally not recommended or possible for patients with poor bone stock or with massive destruction of the femoral condyles. Modular-type distal femoral knee arthroplasty has also been successful in achieving immediate stability and full weight- bearing status. Summary In recent years, there have been marked improvements in tech- niques for achieving secure fixation of pathologic fractures of the femur or prosthetic reconstruction, even in cases of severe tumor destruc- tion. Careful preoperative plan- ning is essential to determine the extent of tumor involvement and to select appropriate reconstruction and implant type. Achievement of stable, durable fixation or prosthet- ic replacement will improve the quality of life for patients with these fractures. 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Anteroposterior (A) and lateral (B) radiographs of the knee reveal large destructive lesion of the distal femur due to metastatic disease originating in the lung. C and D, Radiographs obtained after prophylactic