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Background: Biologic agents may prolong survival of patients with certain kidney and lung adenocarcinomas that have metastasized to bone, and patient response to these agents should be considered when choosing between an endoprosthesis and internal fixation for surgical treatment of femoral metastases., Questions/purposes: Among patients undergoing surgery for femoral metastases of lung or renal cell carcinoma, (1) Does survival differ between patients who receive only cytotoxic chemotherapy and those who either respond or do not respond to biologic therapy? (2) Does postsurgical incidence of local disease progression differ between groups stratified by systemic treatment and response? (3) Does implant survival differ among groups stratified by systemic treatment and response?, Methods: From our institutional longitudinally maintained orthopaedic database, patients were identified by a query initially identifying all patients who carried a diagnosis of renal cell carcinoma or lung carcinoma. Patients who underwent internal fixation or prosthetic reconstruction between 2000 and 2016 for pathologic fracture of the femur and who survived ≥ 1 year after surgery were studied. Patients who received either traditional cytotoxic chemotherapy or a biologic agent were included. Patients were classified as responders or nonresponders to biologic agents based on whether they had clinical and imaging evidence of a response recorded on two consecutive office visits over ≥ 6 months. Endpoints were overall survival from the time of diagnosis, survival after the femoral operation, evidence of disease progression in the femoral operative site, and symptomatic local disease progression for which revision surgery was necessary. Our analysis included 148 patients with renal (n = 26) and lung (n = 122) adenocarcinoma. Fifty-one patients received traditional chemotherapy only. Of 97 patients who received a biologic agent, 41 achieved a response (stabilization/regression of visceral metastases), whereas 56 developed disease progression. We analyzed overall patient survival with the Kaplan-Meier method and used the log-rank test to identify significant differences (p < 0.05) between groups., Results: One-year survival after surgery among patients responsive to biologic therapy was 61% compared with 20% among patients nonresponsive to biologics (p < 0.001) and 10% among those who received chemotherapy only (p < 0.009). With the number of patients we had to study, we could not detect any difference in local progression of femoral disease associated with systemic treatment and response. Radiologic evidence of periimplant local disease progression developed in three (7%) of 41 patients who responded to biologic treatment, two (3%) of 56 patients nonresponsive to biologics, and one (2%) of 51 patients treated with traditional chemotherapy. With the numbers of patients we had, we could not detect a difference in patients who underwent revision. All three patients responsive to biologics who developed local recurrence underwent revision, whereas the two without a response to biologics did not., Conclusions: Biologic therapy improves the overall longevity of some patients with lung and renal metastases to the femur in whom a visceral disease response occurred. In our limited cohort, we could not demonstrate an implant survival difference between such patients and those with shorter survival who may have had more aggressive disease. However, an increased life expectancy beyond 1 year among patients responsive to biologics may increase risk of mechanical failure of fixation constructs., Level of Evidence: Level III, therapeutic study.

Background: Objective means of estimating survival can be used to guide surgical decision-making and to risk-stratify patients for clinical trials. Although a free, online tool ( www.pathfx.org ) can estimate 3- and 12-month survival, recent work, including a survey of the Musculoskeletal Tumor Society, indicated that estimates at 1 and 6 months after surgery also would be helpful. Longer estimates help justify the need for more durable and expensive reconstructive options, and very short estimates could help identify those who will not survive 1 month and should not undergo surgery. Thereby, an important use of this tool would be to help avoid unsuccessful and expensive surgery during the last month of life., Questions/purposes: We seek to provide a reliable, objective means of estimating survival in patients with metastatic bone disease. After generating models to derive 1- and 6-month survival estimates, we determined suitability for clinical use by applying receiver operator characteristic (ROC) (area under the curve [AUC] > 0.7) and decision curve analysis (DCA), which determines whether using PATHFx can improve outcomes, but also discerns in which kinds of patients PATHFx should not be used., Methods: We used two, existing, skeletal metastasis registries chosen for their quality and availability. Data from Memorial Sloan-Kettering Cancer Center (training set, n = 189) was used to develop two Bayesian Belief Networks trained to estimate the likelihood of survival at 1 and 6 months after surgery. Next, data from eight major referral centers across Scandinavia (n = 815) served as the external validation set-that is, as a means to test model performance in a different patient population. The diversity of the data between the training set from Memorial Sloan-Kettering Cancer Center and the Scandinavian external validation set is important to help ensure the models are applicable to patients in various settings with differing demographics and treatment philosophies. We considered disease-specific, laboratory, and demographic information, and the surgeon's estimate of survival. For each model, we calculated the area under the ROC curve (AUC) as a metric of discriminatory ability and the Net Benefit using DCA to determine whether the models were suitable for clinical use., Results: On external validation, the AUC for the 1- and 6-month models were 0.76 (95% CI, 0.72-0.80) and 0.76 (95% CI, 0.73-0.79), respectively. The models conferred a positive net benefit on DCA, indicating each could be used rather than assume all patients or no patients would survive greater than 1 or 6 months, respectively., Conclusions: Decision analysis confirms that the 1- and 6-month Bayesian models are suitable for clinical use., Clinical Relevance: These data support upgrading www.pathfx.org with the algorithms described above, which is designed to guide surgical decision-making, and function as a risk stratification method in support of clinical trials. This updating has been done, so now surgeons may use any web browser to generate survival estimates at 1, 3, 6, and 12 months after surgery, at no cost. Just as short estimates of survival help justify palliative therapy or less-invasive approaches to stabilization, more favorable survival estimates at 6 or 12 months are used to justify more durable, complicated, and expensive reconstructive options.

Background: En bloc resection for treatment of sacral tumors is the approach of choice for patients with resectable tumors who are well enough to undergo surgery, and studies describe patient survival, postoperative complications, and recurrence rates associated with this treatment. However, most of these studies do not provide patient-reported functional outcomes other than binary metrics for bowel and bladder function postresection., Questions/purposes: The purpose of this study was to use validated patient-reported outcomes tools to compare quality of life based on level of sacral resection in terms of (1) physical and mental health; (2) pain; (3) mobility; and (4) incontinence and sexual function., Methods: Our analysis included 33 patients (19 men, 14 women) who had a mean age of 53 years (range, 22-72 years) with a quality-of-life survey administered at a mean postoperative followup of 41 months (range, 6-123 months). The majority of patient-reported quality-of-life outcome surveys for this study were taken from the National Institute of Health's Patient Reported Outcome Measurement Information System (PROMIS) system. To assess physical and mental health, the PROMIS Global Items Survey with physical and mental subscores, Anxiety, and Depression scores were used. Pain outcomes were assessed using PROMIS Pain Intensity and Pain Interference surveys. Patient-reported lower extremity function was assessed using the PROMIS Mobility Survey. Patient-reported quality of life for sexual function was assessed using the PROMIS Sex Interest and Orgasm survey, whereas incontinence was measured using the International Continence Society Voiding and Incontinence scores and the Modified Obstruction and Defecation Score. Surveys were collected prospectively during clinic visits in the postoperative period. Patients were grouped by the level of osteotomy as determined by review of postoperative MRI or CT and half levels were grouped with the more cephalad level. This resulted in the inclusion of total sacrectomy (N = 6), S1 (N = 8), S2 (N = 10), S3 (N = 5), and S4 (N = 4). One-way analysis of variance tests on means or ranks were used to conduct statistical analysis between levels., Results: Patients with more caudal resections had higher physical health (95% confidence interval [CI] total sacrectomy 36-42 versus S4 50-64, p < 0.001), less intense pain (95% CI total sacrectomy 47-60 versus S4 28-37, p < 0.001), less interference resulting from pain (95% CI total sacrectomy 58-69 versus S4 36-51, p = 0.004), higher mobility (95% CI total sacrectomy 24-46 versus S4 59-59, p = 0.002), and were more functionally able to achieve orgasm (95% CI S1 1-1 versus S4 2.2-5.3, p = 0.043). No difference was found for PROMIS Global Item Mental Health Subscore, Sex Interest, Sex Satisfaction, modified obstruction and defecation score, and International Continence Society Voiding and Incontinence although this could be the result of an inadequate sample size., Conclusions: Our analysis on patient-reported quality of life based on the level of bony resection in patients who underwent resection for primary sacral tumor indicates that patients with higher resections have more pain and loss of physical function in comparison to patients with lower resections. Additionally, use of the PROMIS outcomes allows for comparisons to normative data., Level of Evidence: Level III, therapeutic study.

Background: Patients with failed distal femoral megaprostheses often have bone loss that limits reconstructive options and contributes to the high failure rate of revision surgery. The Compress(®) Compliant Pre-stress (CPS) implant can reconstruct the femur even when there is little remaining bone. It differs from traditional stemmed prostheses because it requires only 4 to 8 cm of residual bone for fixation. Given the poor long-term results of stemmed revision constructs, we sought to determine the failure rate and functional outcomes of the CPS implant in revision surgery., Questions/purposes: (1) What is the cumulative incidence of mechanical and other types of implant failure when used to revise failed distal femoral arthroplasties placed after oncologic resection? (2) What complications are characteristic of this prosthesis? (3) What function do patients achieve after receiving this prosthesis?, Methods: We retrospectively reviewed 27 patients who experienced failure of a distal femoral prosthesis and were revised to a CPS implant from April 2000 to February 2013. Indications for use included a minimum 2.5 mm cortical thickness of the remaining proximal femur, no prior radiation, life expectancy > 10 years, and compliance with protected weightbearing for 3 months. The cumulative incidence of failure was calculated for both mechanical (loss of compression between the implant anchor plug and spindle) and other failure modes using a competing risk analysis. Failure was defined as removal of the CPS implant. Followup was a minimum of 2 years or until implant removal. Median followup for patients with successful revision arthroplasty was 90 months (range, 24-181 months). Functional outcomes were measured with the Musculoskeletal Tumor Society (MSTS) functional assessment score., Results: The cumulative incidence of mechanical failure was 11% (95% confidence interval [CI], 4%-33%) at both 5 and 10 years. These failures occurred early at a median of 5 months. The cumulative incidence of other failures was 18% (95% CI, 7%-45%) at 5 and 10 years, all of which were deep infection. Three patients required secondary operations for cortical insufficiency proximal to the anchor plug in bone not spanned by the CPS implant and unrelated to the prosthesis. Median MSTS score was 27 (range, 24-30)., Conclusions: Revision distal femoral replacement arthroplasty after a failed megaprosthesis is often difficult as a result of a lack of adequate bone. Reconstruction with the CPS implant has an 11% failure rate at 10 years. Our results are promising and demonstrate the durable fixation provided by the CPS implant. Further studies to compare the CPS prosthesis and other reconstruction options with respect to survival and functional outcomes are warranted., Level of Evidence: Level IV, therapeutic study.

Background: Manual techniques of reproducing a preoperative plan for primary bone tumor resection using rudimentary devices and imprecise localization techniques can result in compromised margins or unnecessary removal of unaffected tissue. We examined whether a novel technique using computer-generated custom jigs more accurately reproduces a preoperative resection plan than a standard manual technique., Description of Technique: Using CT images and advanced imaging, reverse engineering, and computer-assisted design software, custom jigs were designed to precisely conform to a specific location on the surface of partially skeletonized cadaveric femurs. The jigs were used to perform a hemimetaphyseal resection., Methods: We performed CT scans on six matched pairs of cadaveric femurs. Based on a primary bone sarcoma model, a joint-sparing, hemimetaphyseal wide resection was precisely outlined on each femur. For each pair, the resection was performed using the standard manual technique on one specimen and the custom jig-assisted technique on the other. Superimposition of preoperative and postresection images enabled quantitative analysis of resection accuracy., Results: The mean maximum deviation from the preoperative plan was 9.0 mm for the manual group and 2.0 mm for the custom-jig group. The percentages of times the maximum deviation was greater than 3 mm and greater than 4 mm was 100% and 72% for the manual group and 5.6% and 0.0% for the custom-jig group, respectively., Conclusions: Our findings suggest that custom-jig technology substantially improves the accuracy of primary bone tumor resection, enabling a surgeon to reproduce a given preoperative plan reliably and consistently.

Background: Accurate reproduction of the preoperative plan at the time of surgery is critical for wide resection of primary bone tumors. Robotic technology can potentially help the surgeon reproduce a given preoperative plan, but yielding control of cutting instruments to a robot introduces potentially serious complications. We developed a novel passive ("haptics") robot-assisted resection technique for primary bone sarcomas that takes advantage of robotic accuracy while still leaving control of the cutting instrument in the hands of the surgeon., Questions/purposes: We asked whether this technique would enable a preoperative resection plan to be reproduced more accurately than a standard manual technique., Methods: A joint-sparing hemimetaphyseal resection was precisely outlined on the three-dimensionally reconstructed image of a representative Sawbones femur. The indicated resection was performed on 12 Sawbones specimens using the standard manual technique on six specimens and the haptic robotic technique on six specimens. Postresection images were quantitatively analyzed to determine the accuracy of the resections compared to the preoperative plan, which included measuring the maximum linear deviation of the cuts from the preoperative plan and the angular deviation of the resection planes from the target planes., Results: Compared with the manual technique, the robotic technique resulted in a mean improvement of 7.8 mm of maximum linear deviation from the preoperative plan and 7.9° improvement in pitch and 4.6° improvement in roll for the angular deviation from the target planes., Conclusions: The haptic robot-assisted technique improved the accuracy of simulated wide resections of bone tumors compared with manual techniques., Clinical Relevance: Haptic robot-assisted technology has the potential to enhance primary bone tumor resection. Further bench and clinical studies, including comparisons with recently introduced computer navigation technology, are warranted.

Background: Compliant, self-adjusting compression technology is a novel approach for durable prosthetic fixation of the knee. However, the long-term survival of these constructs is unknown., Questions/purposes: We therefore determined the survival of the Compress prosthesis (Biomet Inc, Warsaw, IN, USA) at 5 and 10 actuarial years and identified the failure modes for this form of prosthetic fixation., Methods: We retrospectively reviewed clinical and radiographic records for all 82 patients who underwent Compress knee arthroplasty from 1998 to 2008, as well as one patient who received the device elsewhere but was followed at our institution. Prosthesis survivorship and modes of failure were determined. Followup was for a minimum of 12 months or until implant removal (median, 43 months; range, 6-131 months); 28 patients were followed for more than 5 years., Results: We found a survivorship of 85% at 5 years and 80% at 10 years. Eight patients required prosthetic revision after interface failure due to aseptic loosening alone (n = 3) or aseptic loosening with periprosthetic fracture (n = 5). Additionally, five periprosthetic bone failures occurred that did not require revision: three patients had periprosthetic bone failure without fixation compromise and two exhibited irregular prosthetic osteointegration patterns with concomitant fracture due to mechanical insufficiency., Conclusions: Compress prosthetic fixation after distal femoral tumor resection exhibits long-term survivorship. Implant failure was associated with patient nonadherence to the recommended weightbearing proscription or with bone necrosis and fracture. We conclude this is the most durable FDA-approved fixation method for distal femoral megaprostheses., Level of Evidence: Level IV, therapeutic study. See Instructions for Authors for a complete description of levels of evidence.

Background: Pathologic proximal femur fractures result in substantial morbidity for patients with skeletal metastases. Surgical treatment is widely regarded as effective; however, failure rates associated with the most commonly used operative treatments are not well defined., Questions/purposes: We therefore compared surgical treatment failure rates among intramedullary nailing, endoprosthetic reconstruction, and open reduction-internal fixation when applied to impending or displaced pathologic proximal femur fractures., Patients and Methods: We retrospectively compared the clinical course of 298 patients who underwent intramedullary nailing (n = 82), endoprosthetic reconstruction (n = 197), or open reduction-internal fixation (n = 19) from 1993 to 2008. Primary outcome was treatment failure, which was defined as reoperation for any reason. Treatment groups were compared for differences in demographic and clinical parameters., Results: The number of treatment failures in the endoprosthetic reconstruction group (3.1%) was significantly lower than in the intramedullary nailing (6.1%) and open reduction-internal fixation (42.1%) groups. The number of revisions requiring implant exchange also was significantly lower for endoprosthetic reconstruction (0.5%), compared with intramedullary nailing (6.1%) and open reduction-internal fixation (42.1%)., Conclusions: Endoprosthetic reconstruction is associated with fewer treatment failures and greater implant durability. Prospective studies are needed to determine the impact of operative strategy on function and quality of life., Level of Evidence: Level III, therapeutic study. See Guidelines for Authors for a complete description of levels of evidence.

Background: High-dose radiation retards bone healing, compromising the surgical results of radiation-induced fractures. Prosthetic replacement has traditionally been reserved as a salvage option but may best achieve the clinical goals of eliminating pain, restoring function and avoiding complications., Questions/purposes: We asked whether patients undergoing prosthetic replacement at index surgery for radiation-related subtrochanteric or diaphyseal fractures of the femur had fewer complications than those undergoing open reduction internal fixation at index operation., Methods: We retrospectively reviewed records from 1045 patients with soft tissue sarcomas treated with surgical resection and high-dose radiation therapy between 1982 and 2009 and identified 37 patients with 39 fractures. We recorded patient demographics, diagnosis, type of surgical resection, total radiation dose, fracture location and pattern, years after radiation the fracture occurred, type of surgical fixation, and associated complications., Results: Patients undergoing prosthetic replacement at index surgery had a lower number of major complications and revision surgeries than those undergoing index open reduction internal fixation. Patients undergoing open reduction internal fixation at index surgery had a nonunion rate of 63% (19 of 30). Fractures located in the metaphysis were more likely to heal than those located in the subtrochanteric or diaphyseal regions., Conclusions: Radiation-induced fractures have poor healing potential. Our data suggest an aggressive approach to fracture treatment with a prosthetic replacement can minimize complications and the need for revision surgery.

Unlabelled: Bone ingrowth promises more durable biologic fixation of megaprostheses. The relative performance of different types of fixation is unknown. We compared the fixation of two forms of biologically fixed femoral components: an intramedullary uncemented press-fit stem (UCS; Group 1, 50 patients) and a Compress((R)) uncemented fixation (CPS; Group 2, 41 patients). In Group 1, the overall Kaplan-Meier prosthetic survival rates were 85% at 5 and 71% at 10 years. Most failures were long-term developments. Aseptic loosening was the primary cause of failure. Stem diameters less than 13.5 mm and a diaphyseal/stem coefficient greater than 2.5 mm were associated with decreased prosthetic survival. In Group 2, the overall rate of CPS survival was 88% at 5 years. Failure of femoral fixation or fracture during the first year was the main reason for revision. Five-year survival rates were similar between the groups and we observed no difference in the functional success of the implants. We found no failures after 1-year followup in Group 2 (CPS). Any difference in prosthetic survival can only be proven by longer-term study or a randomized trial., Level of Evidence: Level III, therapeutic study. See Guidelines for Authors for a complete description of levels of evidence.

Unlabelled: Periprosthetic fractures after massive endoprosthetic reconstructions pose a reconstructive challenge and jeopardize limb preservation. Compressive osseointegration technology offers the promise of relative ease of prosthetic revision, since fixation is achieved by means of a short intramedullary device. We retrospectively reviewed the charts of 221 patients who had Compress((R)) devices implanted in two centers between December, 1996 and December, 2008. The mean followup was 50 months (range, 1-123 months). Six patients (2.7%) sustained periprosthetic fractures and eight (3.6%) had nonperiprosthetic ipsilateral limb fractures occurring from 4 to 79 months postoperatively. All periprosthetic fractures occurred in patients with distal femoral implants (6/154, 3.9%). Surgery was performed in all six patients with periprosthetic femur fractures and for one with a nonperiprosthetic patellar fracture. The osseointegrated interface was radiographically stable in all 14 cases. All six patients with periprosthetic fracture underwent limb salvage procedures. Five patients had prosthetic revision; one patient who had internal fixation of the fracture ultimately underwent amputation for persistent infection. Periprosthetic fractures involving Compress((R)) fixation occur infrequently and most can be treated successfully with further surgery. When implant revision is needed, the bone preserved by virtue of using a shorter intramedullary Compress((R)) device as compared to conventional stems, allows for less complex surgery, making limb preservation more likely., Level of Evidence: Level IV, therapeutic study. See Guidelines for Authors for a complete description of levels of evidence.

Unlabelled: We propose a surgical technique for structural allograft reconstitution of the diaphysis of long bones, maximizing surface contact between host and allograft bone. This method, analogous to a telescope, overlaps the graft and host bone, theoretically increasing bone surface contact substantially. We report the outcome of 22 telescoped allograft junction sites in 19 patients who lacked sufficient host bone to accommodate a regular-length stemmed implant. This joint-sparing reconstruction preserved 15 of 16 adjacent joints at risk for replacement. Five patients needed additional surgery, but none for nonunion. The diaphyseal length could be reconstructed enough so that a short prosthesis (less than the critical 40% of total bone length) could be used. This biologic method to reconstruct major segments of the diaphysis is best suited for patients with quantitatively or qualitatively deficient residual bone stock after tumor resection or prosthetic revision. We believe it is an excellent technique for revision knee megaprostheses when there is a short remnant of proximal femur., Level of Evidence: Level IV, therapeutic study.

We assessed our ability to achieve limb length equality (LLE) in children following limb-sparing surgery for distal femur osteogenic sarcoma using coaxial extendible prostheses in 12 children, averaging 11.6 years old at the time of tumor resection (range, 5.9-15.5 years). All but one child achieved clinical limb length equality. There were 23 extensions, averaging 3.8 extensions per patient (range, 1-5), by an average 13 mm per extension and an average total extension of 49.3 mm per patient extended. Eight children underwent revision surgery after an average of 45.1 months (range, 3-115 months). Aseptic loosening occurred more frequently among children with greater femoral diameter growth. The overall prosthetic survival was 60% at 3 years and 35% at 5 years. The survival until aseptic loosening at 3 and 5 years was 85% and 45%, respectively. Press-fit components survived longer than cemented stems. None of the devices loosened. At skeletal maturity the MSTS functional scores averaged 25. Using a coaxial extendible implant, we efficiently achieved LLE in this population. Prosthetic revision was needed frequently. Younger age and longer resection percentages were associated with shorter prosthetic survival and higher revision/aseptic loosening rates. Femoral diameter growth may contribute to loosening. Early experience with this extendible implant is promising.