Femoral diaphyseal endoprosthetic reconstruction after segmental resection of primary bone tumours

Modular intercalary prosthetic reconstruction for malignant and metastatic tumours of the proximal femur

To illustrate the surgical technique and explore clinical outcomes of the reconstruction for the malignant and metastatic bone tumour of proximal femur with metallic modular intercalary prosthesis. Sixteen patients who underwent modular intercalary prosthetic reconstruction after tumour resection were included from April 2012 and October 2020. Prosthesis and screws parameters, resected bone length and residual bone length, clinical outcomes and survivorship were analyzed. All patients were followed up for an average of 19 months (range 1-74). In our series, 12 patients died of the progression of the primary disease at the final follow-up. The cumulative survivorship since the treatment of proximal femoral metastasis was 78.6% (11 patients) at 6 months and 38.5% (5 patients) at 1 year. The mean MSTS score was 22.25 ± 4.55 among all patients. There were no cases of loosening or breakage of the prostheses, plates or screws, despite the various measurements of prostheses and residual bones. Modular intercalary prosthetic reconstruction was an effective method for malignant tumour of the proximal femur, including the advantages of providing early pain relief, quickly restoring postoperative function, required a short operation time, and preserving the adjacent joints.

Tandem Reconstruction of the Femoral Diaphysis Using an Intercalary Prosthesis and a Fibular Free Flap

BACKGROUND

Femoral diaphyseal reconstructions with metal prostheses have mediocre results because of high mechanical forces that result in eventual implant failure. Biological alternatives require prolonged restrictions on weight-bearing and have high rates of infection, nonunion, and fracture. A novel method of utilizing a vascularized fibula in combination with an intercalary prosthesis was developed to complement the immediate stability of the prosthesis with the long-term biological fixation of a vascularized fibular graft.

METHODS

A prospectively maintained database was retrospectively reviewed to identify patients who underwent reconstruction of an oncological intercalary femoral defect using an intercalary prosthesis and an inline fibular free flap (FFF). They were compared with patients who underwent femoral reconstruction using an intercalary allograft and an FFF.

RESULTS

Femoral reconstruction with an intercalary metal prosthesis and an FFF was performed in 8 patients, and reconstruction with an allograft and an FFF was performed in 16 patients. The mean follow-up was 5.3 years and 8.5 years, respectively (p = 0.02). In the bioprosthetic group, radiographic union of the fibula occurred in 7 (88%) of 8 patients, whereas in the allograft group, 13 (81%) of 16 patients had allograft union (p = 1.00) and all 16 patients had fibular union (p = 0.33). The mean time to fibular union in the bioprosthetic group was 9.0 months, whereas in the allograft group, the mean time to allograft union was 15.3 months (p = 0.03) and the mean time to fibular union was 12.5 months (p = 0.42). Unrestricted weight-bearing occurred at a mean of 3.7 months in the prosthesis group and 16.5 months in the allograft group (p < 0.01). Complications were observed in 2 (25%) of 8 patients in the prosthesis group and in 13 (81%) of 16 patients in the allograft group (p = 0.02). Neither chemotherapy nor radiation affected fibular or allograft union rates. Musculoskeletal Tumor Society scores did not differ significantly between the groups (mean, 26 versus 28; p = 0.10).

CONCLUSIONS

Bioprosthetic intercalary femoral reconstruction with a metal prosthesis and an FFF resulted in earlier weight-bearing, a shorter time to union, fewer operations needed for union, and lower complication rates than reconstruction with an allograft and an FFF.

LEVEL OF EVIDENCE

Therapeutic Level III . See Instructions for Authors for a complete description of levels of evidence.

What Is the Prosthetic Survival After Resection and Intercalary Endoprosthetic Reconstruction for Diaphyseal Bone Metastases of the Humerus and Femur?

BACKGROUND

Large metastatic lesions of the diaphysis can cause considerable pain and result in difficult surgical challenges. Resection and cemented intercalary endoprosthetic reconstruction offer one solution to the problem, but it is an extensive operation that might not be tolerated well by a debilitated patient. The risk of aseptic loosening and revision after intercalary endoprosthetic replacement has varied in previous reports, which have not examined the risk of revision in the context of patient survival.

QUESTIONS/PURPOSES

(1) In a small case series from one institution, what is the survivorship of patients after cemented intercalary endoprosthetic replacement for diaphyseal metastasis, and what is the cumulative incidence of revision for any reason? (2) What are the complications associated with cemented intercalary reconstruction? (3) What is the functional outcome after the procedure as assessed by the MSTS93 score?

METHODS

We retrospectively studied 19 patients with diaphyseal long bone metastases who were treated with resection and cemented intercalary endoprosthetic reconstruction by five participating surgeons at one referral center from 2006 to 2017. There were 11 men and eight women with a median age of 59 years (range 46 to 80 years). The minimum follow-up required for this series was 12 months; however, patients who reached an endpoint (death, radiographic loosening, or implant revision) before that time were included. One of these 19 patients was lost to follow-up but was not known to have died. The median follow-up was 24 months (range 0 to 116 months). Eight of the 19 patients presented with pathologic fractures. Ten of 19 lesions involved the femur, and nine of 19 were in the humerus. The most common pathologic finding was renal cell carcinoma (in 10 of 19). Survival estimates of the patients were calculated using the Kaplan-Meier method. A competing risks estimator was used to evaluate implant survival, using death of the patient as the competing risk. We also estimated the cumulative incidence of aseptic loosening in a competing risk analysis. Radiographs were analyzed for radiolucency at the bone-cement-implant interfaces, fracture, integrity of the cement mantle, and component position stability. Complications were assessed using record review that was performed by an individual who was not involved in the initial care of the patients. Functional outcomes were assessed using the MSTS93 scoring system.

RESULTS

Patient survivorship was 68% (95% CI 50% to 93%) at 1 year, 53% (95% CI 34% to 81%) at 2 years, and 14% (95% CI 4% to 49%) at 5 years; the median patient survival time after reconstruction was 25 months (range 0 to 116 months). In the competing risk analysis, using death as the competing risk, the cumulative incidence of implant revision was 11% (95% CI 2% to 29%) at 1 year and 16% (95% CI 4% to 36%) at 5 years after surgery; however, the cumulative incidence of aseptic loosening (with death as a competing risk) was 22% (95% CI 6% to 43%) at 1 year and 33% (95% CI 13% to 55%) at 5 years after surgery. Other complications included one patient who died postoperatively of cardiac arrest, one patient with delayed wound healing, two patients with bone recurrence, and one patient who experienced local soft tissue recurrence that was excised without implant revision. Total MSTS93 scores improved from a mean of 12.6 ± 8.1 (42% ± 27%) preoperatively to 21.5 ± 5.0 (72% ± 17%) at 3 months postoperatively (p < 0.001) and 21.6 ± 8.5 (72% ± 28%) at 2 years postoperatively (p = 0.98; 3 months versus 2 years).

CONCLUSION

Resection of diaphyseal metastases with intercalary reconstruction can provide stability and short-term improvement in function for patients with advanced metastatic disease and extensive cortical destruction. Aseptic loosening is a concern, particularly in the humerus; however, the competing risk analysis suggests the procedure is adequate for most patients, because many in this series died of disease without undergoing revision.

LEVEL OF EVIDENCE

Level IV, therapeutic study .

Endoprosthetic reconstruction for lower extremity soft tissue sarcomas with bone involvement

BACKGROUND AND OBJECTIVES

Bone resection and endoprosthetic reconstruction (EPR) in the setting of soft tissue sarcoma (STS) management is rare and incurs unique challenges. We aim to report on the surgical and oncological outcomes of this relatively previously undocumented cohort.

METHODS

This is a single-center retrospective review of prospectively collected data for patients who required EPRs following resection of STSs of the lower extremity. Following inclusion criteria, we assessed 29 cases of EPR for primary STS of the lower limb.

RESULTS

The mean age was 54 years (range 18-84). Of the 29 patients, there were 6 total femur, 11 proximal femur, 4 intercalary, and 8 distal femur EPRs. Fourteen of 29 patients (48%) underwent re-operations for surgical complications, with 9 relating to infection (31%). When a matched cohort analysis was performed comparing our cohort to STSs that did not necessitate EPR, a reduced rate of overall survival and metastasis-free survival was found in those requiring EPR.

CONCLUSION

This series identifies a high rate of complication from EPRs performed for STS. Patients should be cautioned about the high rate of infection, surgical complications, and lower overall survival in this setting.

Follow-up of biological reconstruction of epiphysis preserving osteosarcoma around the knee in children: A retrospective cohort study

Limb salvage treatment for malignant bone tumors in children includes prosthetic and biological reconstruction. Early function following prosthesis reconstruction is satisfactory; however, there are several complications. Biological reconstruction is another way to treat bone defects. We evaluated the effectiveness of reconstruction of bone defects by liquid nitrogen inactivation of autologous bone with preserving epiphysis in 5 cases of periarticular osteosarcoma of the knee. We retrospectively selected 5 patients with articular osteosarcoma of the knee who underwent epiphyseal-preserving biological reconstruction in our department between January 2019 and January 2020. Femur involvement occurred in 2 cases and tibia involvement occurred in 3 cases, with an average defect of 18 cm (12-30 cm). The 2 patients with femur involvement were treated with inactivated autologous bone by liquid nitrogen with vascularized fibula transplantation. Among the patients with tibia involvement, 2 were treated with inactivated autologous bone with ipsilateral vascularized fibula transplantation and 1 was treated with autologous inactivated bone with contralateral vascularized fibula transplantation. Bone healing was evaluated by regular X-ray examination. At the end of the follow-up, lower limb length, knee flexion, and extension function were evaluated. Patients were followed up for 24 to 36 months. Average bone-healing time was 5.2 months (3-8 months). All patients achieved bone healing with no tumor recurrence and no distant metastasis and all patients survived. The lengths of both lower limbs were equal in 2 cases, with shortening by ≤1 cm in 1 case and shortening by 2 cm in 1 case. Knee flexion was >90° in 4 cases and between 50 and 60° in 1 case. The Muscle and Skeletal Tumor Society score was 24.2 (range 20-26). Inactivation of autogenous bone with the epiphysis preserved by liquid nitrogen combined with vascularized fibula reconstruction for periarticular osteosarcoma of the knee in children is safe and effective. This technique supports bone healing. Postoperative limb length and function, and short-term effects were satisfactory.

Reconstruction of massive bone defects after femoral tumor resection using two new-designed 3D-printed intercalary prostheses: a clinical analytic study with the cooperative utilization of multiple technologies

BACKGROUND

To reconstruct massive bone defects of the femoral diaphysis and proximal end with limited bilateral cortical bone after joint-preserving musculoskeletal tumor resections, two novel 3D-printed customized intercalary femoral prostheses were applied.

METHODS

A series of nine patients with malignancies who received these novel 3D-printed prostheses were retrospectively studied between July 2018 and November 2021. The proximal and diaphyseal femur was divided into three regions of interest (ROIs) according to anatomic landmarks, and anatomic measurements were conducted on 50 computed tomography images showing normal femurs. Based on the individual implant-involved ROIs, osteotomy level, and anatomical and biomechanical features, two alternative 3D-printed prostheses were designed. In each patient, Hounsfield Unit (HU) value thresholding and finite element analysis were conducted to identify the bone trabecula and calcar femorale and to determine the stress distribution, respectively. We described the characteristics of each prosthesis and surgical procedure and recorded the intraoperative data. All patients underwent regular postoperative follow-up, in which the clinical, functional and radiographical outcomes were evaluated.

RESULTS

With the ROI division and radiographic measurements, insufficient bilateral cortical bones for anchoring the traditional stem were verified in the normal proximal femur. Therefore, two 3D-printed intercalary endoprostheses, a Type A prosthesis with a proximal curved stem and a Type B prosthesis with a proximal anchorage-slot and corresponding locking screws, were designed. Based on HU value thresholding and finite element analysis, the 3D-printed proximal stems in all prostheses maximally preserved the trabecular bone and calcar femorale and optimized the biomechanical distribution, as did the proximal screws. With the 3D-printed osteotomy guide plates and reaming guide plates, all patients underwent the operation uneventfully with a satisfactory duration (325.00 ± 62.60 min) and bleeding volume (922.22 ± 222.36 ml). In the follow-up, Harris Hip and Musculoskeletal Tumor Society scores were ameliorated after surgery (P < 0.001 and P < 0.001, respectively), reliable bone ingrowth was observed, and no major complications occurred.

CONCLUSIONS

Two novel 3D-printed femoral intercalary prostheses, which achieved acceptable overall postoperative outcomes, were used as appropriate alternatives for oncologic patients with massive bone defects and limited residual bone and increased the opportunities for joint-preserving tumor resection. Several scientific methodologies utilized in this study may promote the clinical design proposals of 3D-printed implants.

Long-Term Follow-Up of Biological Reconstruction with Free Fibular Graft after Resection of Extremity Diaphyseal Bone Tumors

This study aimed to evaluate the clinical outcomes and complications of reconstruction with a composite free fibula inside other biological grafts. We retrospectively reviewed 26 patients who underwent reconstruction after bone tumor resection of the diaphysis of the long bone. Surgical data, time to bony union, functional outcomes, and complications were evaluated in all cases. The median follow-up was 72.5 months. The limb salvage rate was 100%. Primary osseous union was achieved in 90.4% of the junctions. The union rates at the metaphyseal and diaphyseal junctions were 100% and 85.7%, respectively (p = 0.255). The mean time of bony union in the upper (87.5%) and lower (91.7%) extremity was 4.6 ± 1.6 months and 6.9 ± 2 months, respectively. The mean MSTS score was 27.2 ± 3.2, with a mean MSTS rating of 90.7%. Complications occurred in 15.4% of the cases. The administration of vascularized or non-vascularized grafts did not significantly influence the union time (p = 0.875), functional outcome (p = 0.501), or blood loss (p = 0.189), but showed differences in operation time (p = 0.012) in lower extremity reconstruction. A composite free fibula inside other biological grafts provides a reasonable and durable option for osseous oncologic reconstruction of the long bone diaphysis of the extremities with an acceptable rate of complications. A higher union rate was achieved after secondary bone grafting. In lower-extremity reconstruction, two plates may be considered a better option for internal fixation. Vascularizing the fibula did not significantly affect the union time.

Intercalary frozen autografts for reconstruction of bone defects following meta-/diaphyseal tumor resection at the extremities

Background

For patients with malignant limb tumors, salvage surgery can be achieved using endoprosthesis or biological reconstructions like allograft or autograft. In carefully selected patients, resected bone can be recycled after sterilization using methods like autoclaving, irradiation, pasteurization or freezing with liquid nitrogen. We evaluated the clinical outcome and complications of malignant limb tumors treated with intercalary resection and frozen autograft reconstruction.

Methods

We reviewed 33 patients whose malignant bone tumors were treated by wide resection and reconstruction with recycling liquid nitrogen-treated autografts between 2006 and 2017. Limb function, bone union at the osteotomy site and complications were evaluated. Functional outcome was assessed using the Musculoskeletal Tumor Society (MSTS) scoring system.

Results

The cohort comprised 16 males and 17 females, with a mean age of 35.4 years (14–76 years). The most common tumor was osteosarcoma (7 cases). Tumors were located in the humerus (5), ulna (1), femur (10) and tibia (17). The mean follow-up was 49.9 months (range 12–127 months). Of the 33 patients, 16 remained disease-free, and 3 were alive with disease. The mean size of the defect after tumor resection was 11.6 cm (range 6–25 cm). Bone union was achieved in 32 patients, with a mean union time of 8.8 months (range 4–18 months). Complications included 1 graft nonunion, 2 infections (1 superficial, 1 deep infection), 1 leg length discrepancy, 2 graft fractures and 3 local recurrences. The mean MSTS score was 87.2% (range 70–100%).

Conclusion

Liquid nitrogen-treated tumor-bearing autograft is an effective option for biological reconstruction after meta-/diaphyseal tumor resection of long bones. This method has excellent clinical outcomes and is especially recommended for patients with no severe osteolytic bone tumors.

Hip reconstruction using a customized intercalary prosthesis with the rhino horn-designed uncemented stem for ultrashort proximal femur segments following tumor resection: a combined biomechanical and clinical study

Background

Hip-preserved reconstruction for patients with ultrashort proximal femur segments following extensive femoral diaphyseal tumor resection is a formidable undertaking. A customized intercalary prosthesis with a rhino horn-designed uncemented stem was developed for the reconstruction of these extensive skeletal defects.

Methods

This study was designed to analyze and compare the differences in the biomechanical behavior between the normal femur and the femur with diaphyseal defects reconstructed by an intercalary prosthesis with different stems. The biomechanical behavior under physiological loading conditions is analyzed using the healthy femur as the reference. Five three-dimensional finite element models (healthy, customized intercalary prosthesis with four different stems implemented, respectively) were developed, together with a clinical follow-up of 12 patients who underwent intercalary femoral replacement.

Results

The biomechanical results showed that normal-like stress and displacement distribution patterns were observed in the remaining proximal femur segments after reconstructions with the rhino horn-designed uncemented stems, compared with the straight stem. Stem A showed better biomechanical performance, whereas the fixation system with Stem B was relatively unstable. The clinical results were consistent with the FEA results. After a mean follow-up period of 32.33 ± 9.12 months, osteointegration and satisfactory clinical outcomes were observed in all patients. Aseptic loosening (asymptomatic) occurred in one patient reconstructed by Stem B; there were no other postoperative complications in the remaining 11 patients.

Conclusion

The rhino horn-designed uncemented stem is outstanding in precise shape matching and osseointegration. This novel prosthesis design may be beneficial in decreasing the risk of mechanical failure and aseptic loosening, especially when Stem A is used. Therefore, the customized intercalary prosthesis with this rhino horn-designed uncemented stem might be a reasonable alternative for the reconstruction of SSPF following extensive tumor resection.

Plate configuration for biological reconstructions of femoral intercalary defect - a finite element evaluation

BACKGROUND AND OBJECTIVE

Biological reconstruction was commonly used for femoral intercalary defect. The initial stability by plate fixation was believed to have an effect on bone union and implant failure. Our study was proposed to explore relationship of plate configuration and initial stability for femoral intercalary reconstruction using allo-/autograft.

METHODS

Femoral intercalary defect models were established with four different plate configurations: (1) Single lateral bridging plate, SLP (2) Lateral bridging plate + Orthogonal adjuvant plate, LP+OAP (3) Lateral bridging plate + Medial adjuvant plate, LP+MAP (4) Lateral bridging plate + Medial bridging plate, LP+MP. A diaphysis defect of 12 cm was simulated, and the removed native femoral bone was used as a structural allograft with the osteotomy gap of 2 mm. Models were analyzed by finite element simulations under an axial compression of 2000N and an axial moment of 10 Nm, respectively.

RESULTS

Axial load: (1) The peak von Mises stress of SLP, LP+OAP, LP+MAP, LP+MP were 993.50 MPa, 335.63 MPa, 240.03 MPa, 281.73 MPa, respectively and LP+MAP was the lowest (p < 0.01); (2) The mean displacement of SLP, LP+OAP, LP+MAP, LP+MP was 0.765, 0.130, 0.121, 0.235 mm, respectively. LP+MAP showed the best stability while SLP had a crash in the medial proximal gap; (3) The LP+MAP configuration had the most uniform stress distribution and the lowest maximum von Mises stress of 79.7 MPa within plates. Axial torsional load: (1) The peak von Mises stress of SLP, LP+OAP, LP+MAP, LP+MP were 431.66Mpa, 120.73 MPa, 72.31 MPa, 109.86 MPa, respectively; (2) The rotation angle of SLP, LP+OAP, LP+MAP, LP+MP was 4.30°, 1.35°, 1.20°, 1.57°, respectively. All of LP+OAP, LP+MAP and LP+MP showed an optimal torsional stability.

CONCLUSIONS

For femoral intercalary reconstruction using allo-/autograft fixed by plates, LP+MAP and LP+MP configurations showed superior stability in terms of axial compression and torsion load by FE simulation. A better stability was believed to be associated with higher union rate and lower hardware failure rate.

Endoprosthetic Reconstruction in Ewing's Sarcoma Patients: A Systematic Review of Postoperative Complications and Functional Outcomes

Ewing's sarcoma (ES) is a rare primary bone cancer managed by radiotherapy, chemotherapy and surgical resection. The existing literature on limb salvage surgery with endoprostheses combines data for ES patients with osteosarcoma. This review aimed to evaluate surgical and functional outcomes of endoprosthetic reconstruction in exclusively Ewing's patients. We believe that this is the first comprehensive review to evaluate the outcomes of limb salvage surgery with endoprostheses exclusively in Ewing's sarcoma patients. Clinical data and outcomes were collected from PubMed, Embase, Medline and Scopus. The inclusion criteria were studies on limb salvage surgery in ES patients, where individual patient data was available. Seventeen studies with a total of 57 Ewing's patients were included in this review. Fifty-three of the ES patients preserved the limb after limb salvage with endoprostheses. The average five-year implant survivorship was 85.9% based on four studies in this review. Postoperative complications were categorised by Henderson's failure modes. Soft tissue failure was the most common, occurring in 35.1% of patients, followed by deep infection in 15.7% of patients. There was a suggestion of 'good' functional outcomes with limb salvage surgery. The salient limitation of this review is the variability and rarity of the patient population. Homogenous data in a larger population is necessary to provide more insight into outcomes of limb reconstruction in ES.

Distal Femoral Replacement as a Salvage Treatment After Desmoplastic Fibroma Resection

Desmoplastic fibroma is an extremely rare primary bone tumor that can mimic the presentation of other bone lesions. We describe the case of a middle-aged male with a mass on the left distal femur initially diagnosed as fibrous dysplasia that underwent a wide margin excision followed by a distal femoral replacement to restore anatomy and functionality. Histologic examination of the complete surgical specimen was consistent with a desmoplastic fibroma. This case is the first report of a successful application of endoprosthetic reconstruction after desmoplastic fibroma resection.

Design and Analysis of Biomedical Scaffolds Using TPMS-Based Porous Structures Inspired from Additive Manufacturing

Gyroid (G) and primitive (P) porous structures have multiple application areas, ranging from thermal to mechanical, and fall in the complex triply periodic minimal surface (TPMS) category. Such intricate bioinspired constructs are gaining attention because they meet both biological and mechanical requirements for osseous reconstruction. The study aimed to develop G and P structures with varying porosity levels from 40% to 80% by modulating the strut thickness to proportionally resemble the stiffness of host tissue. The performance characteristics were evaluated using Ti6Al4V and important relationships between feature dimension, strut thickness, porosity, and stiffness were established. Numerical results showed that the studied porous structures could decrease stiffness from 107 GPa (stiffness of Ti6Al4V) to the range between 4.21 GPa to 29.63 GPa of varying porosities, which matches the human bone stiffness range. Furthermore, using this foundation, a subject-specific scaffold (made of P unit cells with an 80% porosity) was developed to reconstruct segmental bone defect (SBD) of the human femur, demonstrating a significant decrease in the stress shielding effect. Stress transfer on the bone surrounded by a P scaffold was compared with a solid implant which showed a net increase of stress transfer of 76% with the use of P scaffold. In the conclusion, future concerns and recommendations are suggested.

Intercalary allograft reconstruction following femoral tumour resection: mid- and long-term results and benefits of adding a vascularised fibula autograft

Purpose

Bone healing in femoral reconstructions using intercalary allografts can be compromised in a tumour context. There is also a high revision rate for non-union, infection, and fractures in this context. The advantages and disadvantages of an associated vascularised fibula graft (VFG) are still a matter of debate.

Methods

In a multicentre study, we retrospectively analysed 46 allograft reconstructions, operated on between 1984 and 2017, of which 18 were associated with a VFG (VFG+) and 28 without (VFG−), with a minimum follow-up of 2 years. We determined the cumulative probability of bone union as well as the mid- and long-term revision risks for both categories by Kaplan-Meier survival analysis and a multivariate Cox model. We also compared the MSTS scores.

Results

Significant differences in favour of VFG+ reconstruction were observed in the survival analyses for the probability of bone union (log-rank, p = 0.017) and in mid- and long-term revisions (log-rank, p = 0.032). No significant difference was observed for the MSTS, with a mean MSTS of 27.6 in our overall cohort (p = 0.060). The multivariate Cox model confirmed that VFG+ was the main positive factor for bone union, and it identified irradiated allografts as a major risk factor for the occurrence of mid- and long-term revisions.

Conclusion

Bone union was achieved earlier in both survival and Cox model analyses for the VFG+ group. It also reduced the mid- and long-term revision risk, except when an irradiated allograft was used. In case of a tumour, we thus recommend using VFG+ from a fresh-frozen allograft, as it appears to be a more reliable long-term option.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12957-022-02650-x.

Outcomes of Intercalary Endoprostheses as a Treatment for Metastases in the Femoral and Humeral Diaphysis

BACKGROUND

The purpose of this study was to evaluate the implant survival, functional score and complications of intercalary endoprostheses implanted for metastatic involvement of the femoral and humeral diaphysis.

METHODS

The selected group covered patients with bone metastasis who were surgically treated with an intercalary endoprosthesis between 2012 and 2021. The functional outcome was evaluated with the Musculoskeletal Tumor Society (MSTS) scoring system, and complications were evaluated by using the failure classification for prosthetics designed by Henderson.

RESULTS

The mean follow-up was 29.8 months. In our group of 25 patients with 27 intercalary endoprostheses (18 femurs, 9 humeri), there were 7 implant-related complications (25.9%), which were more common on the humerus (4 cases, 44.4%) than on the femur (3 cases, 16.7%). Only type II failure-aseptic loosening (5 cases, 18.5%)-and type III failure-structural failure (2 cases, 7.4%)-occurred. There was a significantly higher risk of aseptic loosening of the endoprosthesis in the humerus compared with that in the femur (odds ratio 13.79, 95% confidence interval 1.22-151.05, p = 0.0297). The overall cumulative implant survival was 92% 1 year after surgery and 72% 5 years after surgery. The average MSTS score was 82%. The MSTS score was significantly lower (p = 0.008) in the humerus (75.9%) than in the femur (84.8%).

CONCLUSIONS

The resection of bone metastases and replacement with intercalary endoprosthesis has excellent immediate functional results with an acceptable level of complications in prognostically favourable patients.

Hip-Preserved Reconstruction Using a Customized Cementless Intercalary Endoprosthesis With an Intra-Neck Curved Stem in Patients With an Ultrashort Proximal Femur: Midterm Follow-Up Outcomes

Background: Hemiarthroplasty is widely used for proximal femoral reconstruction after tumor resection. However, complications of hemiarthroplasty include infection, hip dislocation, and acetabular wear. This study aimed to: (1) evaluate the reliability and validity of a customized cementless intercalary endoprosthesis (CCIE) with an intra-neck curved stem (INCS) to reconstruct femoral diaphyseal defects with an ultrashort proximal femur (UPF); (2) assess the lower extremity function after reconstruction with this endoprosthesis; and (3) identify the postoperative complications associated with the use of this endoprosthesis.

Methods: Between October 2015 and May 2019, 13 patients underwent reconstruction with a CCIE with an INCS. The distance from the center of the femoral head to the midline of the body and the apex of the acetabulum was measured preoperatively. Additionally, the distance from the tip of the INCS to the midline of the body and the apex of the acetabulum was measured postoperatively. The femoral neck–shaft angle was also measured pre- and postoperatively. After an average follow-up duration of 46 months, the radiological outcomes of the CCIE with an INCS were analyzed. Function was evaluated with the Musculoskeletal Tumor Society (MSTS) score. Pain was measured using a paper visual analog scale (VAS) pre- and postoperatively, and complications were recorded.

Results: Compared with our preoperative design, we found no significant difference in the postoperative distance from the tip of the INCS to the body midline (p = 0.187) and the apex of the acetabulum (p = 0.159), or in the postoperative femoral neck–shaft angle (p = 0.793). Thus, the INCS positions were deemed accurate. The average MSTS score was 26 (range: 24–28), and the VAS score was significantly decreased postoperatively compared with preoperatively (p < 0.0001). No patients developed aseptic loosening, infection, periprosthetic fracture, or prosthetic fracture as of the last follow-up.

Conclusion: The CCIE with an INCS was a valid and reliable method for reconstructing femoral diaphyseal defects with a UPF following malignant tumor resection. Postoperative lower extremity function was acceptable, with an appropriate individualized rehabilitation program, and the incidence of complications was low.

Lower Limb Reconstruction Using Tibial Strut Autograft after Resection of Primary Malignant Bone Tumors in Skeletally Immature Patients

Background

Reconstruction of large bone defects in skeletally immature patients remains a surgical challenge. We report the long-term clinical outcomes of a novel surgical technique for lower limb reconstruction using the tibia as a strut autograft following resection of primary malignant bone tumors in skeletally immature patients.

Methods

We retrospectively reviewed the medical records of six patients diagnosed with lower limb primary bone sarcoma. All patients underwent tumor resection and reconstruction using tibial strut autograft. The radiological and clinical outcomes including complications at the recipient and donor sites were assessed.

Results

The mean age at presentation was ten years (range 6-15 years). Two cases had osteosarcoma and four had Ewing sarcoma. The mean length of the resected tumor and tibial autografts were 20.83 and 19.33 cm respectively. Union at both ends was achieved in five grafts while one graft achieved union only at the distal end. The mean time for union of the proximal and distal junctions was 4 and 8.8 months respectively. The mean follow-up period was 8.4 years (range 14 months-20 years). One patient developed a foot drop, and three patients underwent subsequent joint arthrodesis (2 knees and 1 ankle). The mean musculoskeletal tumor society functional score was 80.8%. Two patients had clinically significant leg-length discrepancy that needs further lengthening procedure. Four patients survived with no evidence of disease and two patients died due to their primary oncologic disease. All donor sites regenerated, with the earliest signs of new bone formation at (2-4) weeks post-operatively.

Conclusion

Reconstruction using non-vascularized‎ tibia strut autograft after resection of primary malignant lower limb bone tumors can be a viable alternative method for reconstructing large bone defects in the immature skeleton.

Computer navigation-aided joint-preserving resection and custom-made endoprosthesis reconstruction for bone sarcomas: long-term outcomes

BACKGROUND

Computed tomography (CT) and magnetic resonance imaging (MRI) data can be fused to identify the tumor boundaries. This enables surgeons to set close but tumor-free surgical margins and excise the tumor more precisely. This study aimed to report our experience in performing computer navigation-aided joint-preserving resection and custom-made endoprosthesis reconstruction to treat bone sarcoma in the diaphysis and metaphysis of the femur and tibia.

METHODS

Between September 2008 and December 2015, 24 patients with bone sarcomas underwent surgical resection and joint-sparing reconstruction under image-guided computer navigation. The cohort comprised 16 males and eight females with a median age of 19.5 years (range: 12-48 years). The tumor location was the femoral diaphysis in three patients, distal femur in 19, and proximal tibia in two. The tumors were osteosarcoma (n = 15), chondrosarcoma (n = 3), Ewing sarcoma (n = 3), and other sarcomas (n = 3). We created a pre-operative plan for each patient using navigation system software and performed navigation-aided resection before reconstructing the defect with a custom-made prosthesis with extracortical plate fixation.

RESULTS

Pathological examination verified that all resected specimens had appropriate surgical margins. The median distance from the tumor resection margin to the joint was 30 mm (range: 13-80 mm). The median follow-up duration was 62.5 months (range: 24-134 months). Of the 24 patients, 21 remain disease free, one is alive with disease, and two died of the disease. One patient developed local recurrence. Complications requiring additional surgical procedures occurred in six patients, including one with wound hematoma, one with delayed wound healing, one with superficial infection, one with deep infection, and two with mechanical failure of the prosthesis. The mean Musculoskeletal Tumor Society score at the final follow-up was 91% (range: 80%-100%). The 5- and 10-year implant survival rates were 91.3% and 79.9%, respectively.

CONCLUSIONS

Computer navigation-aided joint-preserving resection and custom-made endoprosthesis reconstruction with extracortical plate fixation is a reliable surgical treatment option for bone sarcoma in the diaphysis and metaphysis of the femur and tibia.

Is three-dimensional-printed custom-made ultra-short stem with a porous structure an acceptable reconstructive alternative in peri-knee metaphysis for the tumorous bone defect?

Background

Long-lasting reconstruction after extensive resection involving peri-knee metaphysis is a challenging problem in orthopedic oncology. Various reconstruction methods have been proposed, but they are characterized by a high complication rate. The purposes of this study were to (1) assess osseointegration at the bone implant interface and correlated incidence of aseptic loosening; (2) identify complications including infection, endoprosthesis fracture, periprosthetic fracture, leg length discrepancy, and wound healing problem in this case series; and (3) evaluate the short-term function of the patient who received this personalized reconstruction system.

Methods

Between September 2016 and June 2018, our center treated 15 patients with malignancies arising in the femur or tibia shaft using endoprosthesis with a 3D-printed custom-made stem. Osseointegration and aseptic loosening were assessed with digital tomosynthesis. Complications were recorded by reviewing the patients’ records. The function was evaluated with the 1993 version of the Musculoskeletal Tumor Society (MSTS-93) score at a median of 42 (range, 34 to 54) months after reconstruction.

Results

One patient who experienced early aseptic loosening was managed with immobilization and bisphosphonates infusion. All implants were well osseointegrated at the final follow-up examination. There are two periprosthetic fractures intraoperatively. The wire was applied to assist fixation, and the fracture healed at the latest follow-up. Two patients experienced significant leg length discrepancies. The median MSTS-93 score was 26 (range, 23 to 30).

Conclusions

A 3D-printed custom-made ultra-short stem with a porous structure provides acceptable early outcomes in patients who received peri-knee metaphyseal reconstruction. With detailed preoperative design and precise intraoperative techniques, the reasonable initial stability benefits osseointegration to osteoconductive porous titanium, and therefore ensures short- and possibly long-term durability. Personalized adaptive endoprosthesis, careful intraoperative operation, and strict follow-up management enable effective prevention and treatment of complications. The functional results in our series were acceptable thanks to reliable fixation in the bone-endoprosthesis interface and an individualized rehabilitation program. These positive results indicate this device series can be a feasible alternative for critical bone defect reconstruction. Nevertheless, longer follow-up is required to determine whether this technique is superior to other forms of fixation.

Does the Addition of a Vascularized Fibula Improve the Results of a Massive Bone Allograft Alone for Intercalary Femur Reconstruction of Malignant Bone Tumors in Children?

BACKGROUND

Massive bone allograft with or without a vascularized fibula is a potentially useful approach for femoral intercalary reconstruction after resection of bone sarcomas in children. However, inadequate data exist regarding whether it is preferable to use a massive bone allograft alone or a massive bone allograft combined with a vascularized free fibula for intercalary reconstructions of the femur after intercalary femur resections in children. Because the addition of a vascularized fibula adds to the time and complexity of the procedure, understanding more about whether it reduces complications and improves the function of patients who undergo these resections and reconstructions would be valuable for patients and treating physicians.

QUESTIONS/PURPOSES

In an analysis of children with bone sarcomas of the femur who underwent an intercalary resection and reconstruction with massive bone allograft with or without a vascularized free fibula, we asked: (1) What was the difference in the surgical time of these two different surgical techniques? (2) What are the complications and number of reoperations associated with each procedure? (3) What were the Musculoskeletal Tumor Society scores after these reconstructions? (4) What was the survival rate of these two different reconstructions?

METHODS

Between 1994 and 2016, we treated 285 patients younger than 16 years with a diagnosis of osteosarcoma or Ewing sarcoma of the femur. In all, 179 underwent resection and reconstruction of the distal femur and 36 patients underwent resection and reconstruction of the proximal femur. Additionally, in 70 patients with diaphyseal tumors, we performed total femur reconstruction in four patients, amputation in five, and a rotationplasty in one. The remaining 60 patients with diaphyseal tumors underwent intercalary resection and reconstruction with massive bone allograft with or without vascularized free fibula. The decision to use a massive bone allograft with or without a vascularized free fibula was probably influenced by tumor size, with the indication to use the vascularized free fibula in longer reconstructions. Twenty-seven patients underwent a femur reconstruction with massive bone allograft and vascularized free fibula, and 33 patients received massive bone allograft alone. In the group with massive bone allograft and vascularized fibula, two patients were excluded because they did not have the minimum data for the analysis. In the group with massive bone allograft alone, 12 patients were excluded: one patient was lost to follow-up before 2 years, five patients died before 2 years of follow-up, and six patients did not have the minimum data for the analysis. We analyzed the remaining 46 children with sarcoma of the femur treated with intercalary resection and biological reconstruction. Twenty-five patients underwent femur reconstruction with a massive bone allograft and vascularized free fibula, and 21 patients had reconstruction with a massive bone allograft alone. In the group of children treated with massive bone allograft and vascularized free fibula, there were 17 boys and eight girls, with a mean ± SD age of 11 ± 3 years. The diagnosis was osteosarcoma in 14 patients and Ewing sarcoma in 11. The mean length of resection was 18 ± 5 cm. The mean follow-up was 117 ± 61 months. In the group of children treated with massive bone allograft alone, there were 13 boys and eight girls, with a mean ± SD age of 12 ± 2 years. The diagnosis was osteosarcoma in 17 patients and Ewing sarcoma in four. The mean length of resection was 15 ± 4 cm. The mean follow-up was 130 ± 56 months. Some patients finished clinical and radiological checks as the follow-up exceeded 10 years. In the group with massive bone allograft and vascularized free fibula, four patients had a follow-up of 10, 12, 13, and 18 years, respectively, while in the group with massive bone allograft alone, five patients had a follow-up of 10 years, one patient had a follow-up of 11 years, and another had 13 years of follow-up. In general, there were no important differences between the groups in terms of age (mean difference 0.88 [95% CI -0.6 to 2.3]; p = 0.26), gender (p = 0.66), diagnosis (p = 0.11), and follow up (mean difference 12.9 [95% CI-22.7 to 48.62]; p = 0.46). There was a difference between groups regarding the length of the resection, which was greater in patients treated with a massive bone allograft and vascularized free fibula (18 ± 5 cm) than in those treated with a massive bone allograft alone (15 ± 4 cm) (mean difference -3.09 [95% CI -5.7 to -0.4]; p = 0.02). Complications related to the procedure like infection, neurovascular compromise, and graft-related complication, such as fracture and nonunion of massive bone allograft or vascularized free fibula and implant breakage, were analyzed by chart review of these patients by an orthopaedic surgeon with experience in musculoskeletal oncology. Survival of the reconstructions that had no graft or implant replacement was the endpoint. The Kaplan-Meier test was performed for a survival analysis of the reconstruction. A p value less than 0.05 was considered significant.

RESULTS

The surgery was longer in patients treated with a massive bone allograft and vascularized free fibula than in patients treated with a massive bone allograft alone (10 ± 0.09 and 4 ± 0.77 hours, respectively; mean difference -6.8 [95% CI -7.1 to -6.4]; p = 0.001). Twelve of 25 patients treated with massive bone allograft and vascularized free fibula had one or more complication: allograft fracture (seven), nonunion (four), and infection (four). Twelve of 21 patients treated with massive bone allograft alone had the following complications: allograft fracture (five), nonunion (six), and infection (one). The mean functional results were 26 ± 4 in patients with a massive bone allograft and vascularized free fibula and 27 ± 2 in patients with a massive bone allograft alone (mean difference 0.75 [95% CI -10.6 to 2.57]; p = 0.39). With the numbers we had, we could not detect a difference in survival of the reconstruction between patients with a massive bone allograft and free vascularized fibula and those with a massive bone allograft alone (84% [95% CI 75% to 93%] and 87% [95% CI 80% to 94%], respectively; p = 0.89).

CONCLUSION

We found no difference in the survival of reconstructions between patients treated with a massive bone allograft and vascularized free fibula and patients who underwent reconstruction with a massive bone allograft alone. Based on this experience, our belief is that we should reconstruct these femoral intercalary defects with an allograft alone and use a vascularized fibula to salvage the allograft only if a fracture or nonunion occurs. This approach would have resulted in about half of the patients we treated not undergoing the more invasive, difficult, and risky vascularized procedure.Level of Evidence Level III, therapeutic study.

Intercalary reconstruction following resection of diaphyseal bone tumors: A systematic review

INTRODUCTION

The options for the reconstruction of diaphyseal defects following the resection of bone tumors include biological or prosthetic implants. The purpose of our study was to evaluate different types of intercalary reconstruction techniques, including massive bone allograft, extracorporeal devitalized autograft, vascularized free fibula, and modular prosthesis.

METHODS

We performed a systematic review of articles using the terms diaphyseal bone tumor and intercalary reconstruction. All the studies reporting the non-oncological complications such as infection, nonunion and fracture of the intercalary reconstructions were included. We excluded articles published before 2000 or did not involve humans in the study. Case reports, reviews, technique notes and opinion articles were also excluded based on the abstracts. Thirty-three articles included in this review were then studied to evaluate failure rates, complications and functional outcome of different surgical intercalary reconstruction techniques.

RESULTS

Nonunion rates of allograft ranged 6%-43%, while aseptic loosening rates of modular prosthesis ranged 0%-33%. Nonunion rates of allograft alone and allograft with a vascularized fibula graft ranged 6%-43% and 0%-33%, respectively. Fracture rates of allograft alone and allograft with a vascularized fibula graft ranged 7%-45% and 0%-44%, respectively. Infection rates of allograft alone and allograft with a vascularized fibula graft ranged 0%-28% and 0%-17%, respectively. All of the allograft (range: 67%-92%), extracorporeal devitalized autograft including irradiation (87%), autoclaving (70%), pasteurization (88%), low-heat (90%) or freezing with liquid nitrogen (90%), and modular prosthesis (range: 77%-93%) had similar Musculoskeletal Tumor Society functional scores. Addition of a vascularized fibula graft to allograft did not affect functional outcome [allograft with a vascularized fibula graft (range: 86%-94%) vs. allograft alone (range: 67%-92%)].

CONCLUSION

Aseptic loosening rates of modular prosthesis seem to be less than nonunion rates of allograft. Adding a vascularized fibula graft to allograft seems to increase bone union rate and reduce the risk of fractures and infections, though a vascularized fibula graft needs longer surgical time and has the disadvantage of donor site morbidity. These various intercalary reconstruction techniques with or without a vascularized fibula autograft had similar functional outcome.

Long-Term Clinical Outcomes of Intercalary Allograft Reconstruction for Lower-Extremity Bone Tumors

BACKGROUND

Improved survival rates for patients with primary bone tumors of the extremities have increased the demand for reliable and durable reconstruction techniques. Some authors have stated that, after successful ingrowth, allografts are a durable long-term solution. This hypothesis is largely based on small studies with short-to-midterm follow-up. In order to determine the durability of intercalary allograft reconstructions in the lower extremities, we evaluated the long-term clinical outcomes at a minimum of 10 years.

METHODS

All patients who received an intercalary allograft reconstruction in a lower extremity between 1980 and 2006 were included in this retrospective multicenter cohort study. One hundred and thirty-one patients with a median age of 19 years were included. Eighty-nine (68%) had a femoral reconstruction, and 42 (32%) had a tibial reconstruction. The most prevalent diagnoses were osteosarcoma (55%), Ewing sarcoma (17%), and chondrosarcoma (12%). The median follow-up was 14 years. A competing risk model was employed to estimate the cumulative incidences of mechanical failure and infection. Patient mortality or progression of the disease was used as a competing event.

RESULTS

Nonunion occurred in 21 reconstructions (16%), after a median of 16 months, and was associated with intramedullary nail-only fixation (p < 0.01) and fixation with nonbridging plate(s) (p = 0.03). Allograft fracture occurred in 25 reconstructions (19%) after a median of 42 months (range, 4 days to 21.9 years). Thirteen (52%) of the allograft fractures occurred within 5 years; 8 (32%), between 5 and 10 years; and 4 (16%), at >10 years. With failure for mechanical reasons as the end point, the cumulative incidences of reconstruction failure at 5, 10, and 15 years were 9%, 14%, and 21%, respectively.

CONCLUSIONS

Intercalary allograft reconstruction is an acceptable reconstructive option, mainly because of the absence of superior alternatives with a known track record. However, a considerable and continuing risk of mechanical complications should be taken into account.

LEVEL OF EVIDENCE

Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.

3D Finite Element Analysis of the Modular Prosthesis with Tooth Mechanism of the Femoral Shaft

Objectives

To evaluate the mechanical properties and provide a theoretical basis of a diaphyseal prosthesis with tooth mechanism using the finite element analysis method from the point of view of biomechanics.

Methods

A 3D digital femur model was generated based on a 28‐year‐old healthy man's femoral computed tomography (CT) data in Mimics 17.0 and the customized diaphyseal prostheses with/without tooth mechanism were designed in SolidWorks 2016. The 3D femur model after 8 cm osteotomy in the middle of its shaft and the prostheses with/without tooth mechanism was imported into Abaqus 2016 and the finite element analysis models were established. Three biomechanical tests (compression test, torsion test, and 3P‐bending test) under broken load were simulated in FEA to evaluate the performance of the prostheses.

Results

The stress distributions of the two prostheses were similar and the maximum von Mises stresses placed on them were very close in each test. The maximum von Mises stresses on the prosthesis with tooth mechanism were 31.55, 319.7, and 447.4 MPa, respectively, and those on the prosthesis without tooth mechanism were 26.26, 300.4, and 455.2 MPa, respectively, in the compression, torsion, and 3P‐bending tests. The maximum von Mises stresses on them were far below the ultimate tensile strength or ultimate compressive strength of the titanium alloy.

Conclusions

The diaphyseal prosthesis with tooth mechanism is helpful to adjust the rotation of the long bone during operation. Compared with the conventional diaphyseal prosthesis (without tooth mechanism), the diaphyseal prosthesis with tooth mechanism also has a good biomechanical performance and does not increase the risk of prosthetic failure.

Reconstruction with biological methods following intercalary excision of femoral diaphyseal tumors

AIM

The aim of this study was to assess outcomes of biological (nonvascularized fibula grafts and extracorporeal irradiated autologous bone grafts) methods used for reconstruction of intercalary defects after resection of femoral diaphyseal tumors.

MATERIALS AND METHODS

This study included 28 patients who had undergone intercalary resection in femoral diaphyseal tumors between 2011 and 2016. The mean follow-up period was 24 months (range 12-57 months).

RESULTS

The mean union time for diaphyseo-diaphyseal union was 10.5 and 11 months in nonvascularized fibula group and extracorporeal radiotherapy (ECRT) group, respectively. The mean union time for metaphyseo-diaphyseal union was 6.5 months in both nonvascularized fibula and ECRT groups. Six patients had distant metastasis, and one patient had local recurrence. The mean Musculoskeletal Tumor Society score was 28 at the last follow-up. Two patients had surgical site infection in the nonvascularized fibula group. Implant failure was found in one patient of the ECRT group requiring revision surgery. Three patients had nonunion (two from the nonvascularized fibula group and one from the ECRT group).

CONCLUSION

The present study indicates that the biological reconstruction modalities provide good functional outcomes in diaphyseal tumors of femur. Nonvasularized fibula and ECRT-treated autografts reconstruction provides good results, and union timing is comparable. The outcomes of the current study are promising as compared to the results in the reviewed literature. The reconstruction method depends on the resources available at the oncological center and the conversance with the method of the treating surgeon.

Reconstruction of intercalary bone defect after resection of malignant bone tumor

Due to accurate preoperative imaging techniques, early diagnosis and effective chemotherapy, many tumors arising in the metaphyseo-diaphyseal regions of long bones can be segmentally resected with joint preservation. The intercalary resection of malignant bone tumor results in a bone defect which can represent a challenging reconstructive problem. The most commonly used surgical reconstructive options for these defects include biologic reconstructions such as allografts, vascularized fibular grafts, autogenous extracorporeally devitalized tumor bearing bone graft, combination of allografts or devitalized autografts with vascularized fibular grafts, segmental bone transport, or induced membrane technique. Nonbiologic reconstructions, on the other hand, use intercalary endoprostheses. Every patient should be carefully evaluated and the reconstructive option should be individually selected. The aim of this article is to discuss the surgical options of reconstruction of bone defects after intercalary resection of malignant bone tumors with reviewing of their indications, advantages, disadvantages and complications.

Onlay vascularized fibular grafting as a salvage procedure for the management of nonunion after reconstruction of the femur following tumor resection

PURPOSE

The femur is prone to nonunion after biologic reconstruction following tumor resection, due to high bending forces. Nonunion at the host-graft junction is difficult to treat since the graft is in an avascular state. We aimed to investigate the clinical and radiographic results of an onlay free vascularized fibular grafting (VFG) as a salvage procedure for nonunion management after biologic reconstruction of the femur following bone tumor resection.

METHODS

We retrospectively reviewed 10 patients (8 men and 2 women, median age: 15.5 years, range: 10-47) who underwent an onlay VFG for nonunion after intercalary reconstruction of the femur using an allograft ( n = 7) or pasteurized autograft ( n = 3), following tumor resection. The median follow-up period after VFG was 85.7 (24.6-163.5) months.

RESULTS

The median time to union between the host bone and the VFG osteotomy sites was 3.5 (2.8-4.5) months. The median time to union at the host-graft junctions was 10.6 (6.6-12.7) months. Two postoperative complications requiring revision surgery occurred in two patients: one graft fracture and one deep infection with synchronous graft fracture. Internal fixation was required in the patient with graft fracture. The patient with the infection and synchronous graft fracture was treated using debridement, antibiotics, and an external fixator. The median Musculoskeletal Tumor Society functional score was 88% (60-97%) at the final follow-up.

CONCLUSION

Onlay VFG as a salvage procedure for nonunion of a biologic intercalary reconstruction of the femur after tumor resection is a useful treatment option.

Sarcoma of the Lower Limb: Reconstructive Surgeon's Perspective

Management of sarcomas in the lower extremities have evolved from amputations to limb-preserving surgeries with evidence to support that they have equal overall survival, albeit with better functional outcome. The challenge of reconstruction lies in providing a durable, functional, and aesthetically pleasing limb. However, limb-preserving intention should not delay interventions that provide a survival benefit such as chemotherapy and radiotherapy. The advent of radiotherapy and chemotherapy also has implications on wound healing and should be considered during the reconstructive process. This article reviews the methodical approach, reconstructive strategies, and considerations for the reconstructive surgeon with respect to the lower extremity after sarcoma excision.

Causes and Frequencies of Reoperations After Endoprosthetic Reconstructions for Extremity Tumor Surgery: A Systematic Review

BACKGROUND

Excision of bone tumors and endoprosthetic reconstruction allow patients early weightbearing and a potential functional advantage compared with amputation. These reconstructions do not restore the limb to normal status, however, and patients are subject to complications that may result in revision or loss of the limb. Because better understanding of these complications based on current information might help the patient and surgeon in decision-making, we undertook a systematic review of studies published on this topic.

QUESTIONS/PURPOSES

(1) What are the primary modes and proportion of failure of tumor endoprostheses in patients undergoing reconstruction after excision of primary extremity bone sarcomas?

METHODS

We systematically searched MEDLINE, Embase, and the Cochrane Library for all studies published from April 15, 1998, to April 15, 2018. Three reviewers independently reviewed studies reporting endoprosthetic reconstruction survival and events requiring revision for primary extremity bone tumors treated with endoprosthetic reconstruction for inclusion and performed independent data extraction. We excluded all studies with fewer than five patients, any systematic review/meta-analyses, and any study not reporting on primary extremity bone tumors. All discrepancies were resolved by the study's senior author. Data extracted from included studies were any reoperation event for wound dehiscence, any operative fixation for a pathologic fracture, and any revision of the primary endoprosthesis for implant wear or breakage, deep infection not amenable to prosthesis retention, or for local recurrence. We assessed the overall quality of the evidence with the Methodological Index for Non-Randomized Studies (MINORS) approach with a higher MINORS score representative of a more methodologically rigorous study with a total possible score of 16 points for noncomparative and 24 points for comparative studies. Forty-nine studies met criteria for inclusion from an initial search return of 904 studies, of which no studies were randomized controlled trials. From a total patient population of 2721, there was a mean followup of 93 months (range, 1-516 months) with loss to followup or death occurring in 447 of 2118 (21%) patients with six studies not providing loss to followup data. The mean MINORS score was 14 for prospective studies and 11 for retrospective studies.

RESULTS

Overall, there were 1283 reoperations among the 2721 (47%) patients. Reoperation for mechanical endoprosthetic events (soft tissue dehiscence or periarticular soft tissue instability, aseptic loosening, or implant wear/fracture) occurred in 907 of 2721 (33%) patients. Aseptic loosening occurred at a mean of 75 months (range, 1-376 months) in 212 of 315 patients (67%). Deep infection requiring removal of the initial prosthesis occurred in 247 of 2721 (9%) patients with deep infection occurring at a mean of 24 months (range, 1-372 months) in the 190 infections (77%) with time to infection data available. Local recurrence rates requiring revision or amputation occurred in 129 (5%) of all patients. There was an overall primary endoprosthesis survival rate without any surgical reintervention of 63% among reporting studies at a mean of 79 months followup.

CONCLUSIONS

Failures of endoprosthetic reconstructions after extremity tumor surgery are common, most often resulting from implant wear or fracture, aseptic loosening, and infection. Importantly, the aggregated data are the first to attempt to quantify the time to specific complication types within this patient population. Deep infection not amenable to endoprosthesis retention appears to occur approximately 2 years postoperatively in most patients, with aseptic loosening occurring most commonly at 75 months. Although endoprosthetic reconstruction is one of the most common forms of reconstruction after bone tumor resection, the quality of published evidence regarding this procedure is of low quality with high loss to followup and data quality limiting interstudy analysis. The quality of the evidence is low with high loss to followup and inconsistent reporting of times to reintervention events. Although the most common modes of endoprosthetic failure in this population are well known, creation of quality prospective, collaborative databases would assist in clarifying and informing important elements of the followup process for these patients.

LEVEL OF EVIDENCE

Level IV, therapeutic study.

Failure rates and functional results for intercalary femur reconstructions after tumour resection

PURPOSE

To compare the results for patients treated with intercalary endoprosthetic replacement (EPR) or intercalary allograft reconstruction for diaphyseal tumours of the femur in terms of: (1) reconstruction failure rates; (2) cause of failure; (3) risk of amputation of the limb; and (4) functional result.

METHODS

Patients with bone sarcomas of the femoral diaphysis, treated with en bloc resection and reconstructed with an intercalary EPR or allograft, were reviewed. A total of 107 patients were included in the study (36 EPR and 71 intercalary allograft reconstruction). No differences were found between the two groups in terms of follow-up, age, gender and the use of adjuvant chemotherapy.

RESULTS

The probability of failure for intercalary EPR was 36% at 5 years and 22% for allograft at 5 years (p = 0.26). Mechanical failures were the most prevalent in both types of reconstruction. Aseptic loosening and implant fracture are the main cause in the EPR group. For intercalary allograft reconstructions, fracture followed by nonunion was the most common complication. Ten-year risk of amputation after failure for both reconstructions was 3%. There were no differences between the groups in terms of the mean Musculoskeletal Tumor Society score (27.4, range 16-30 vs. 27.6, range 17-30).

CONCLUSIONS

We have demonstrated similar failure rates for both reconstructions. In both techniques, mechanical failure was the most common complication with a low rate of limb amputation and good functional results.

LEVEL OF EVIDENCE

Level III, therapeutic study.

Solitary Metastatic Lesion of the Tibia from Clear Cell Renal Carcinoma: A Case Report of Segmental Skeletal Resection, Intercalary Allograft Over Reamed Nailing and Soleus Flap Interposition

BACKGROUND Renal cell carcinoma (RCC) is the most common malignancy of the kidney, with clear cell (ccRCC) subtype identified in 85% of the cases; one-third of these patients experience synchronous metastatic disease, while 20-30% of the remaining patients develop metachronous metastatic RCC. The axial skeleton (pelvis and sacrum) is the second most common location (following the lungs), with a reported incidence of 35%. Diaphysis of the long bones is rarely involved, with the tibia being an even rarer site of metastasis. CASE REPORT We present a rare case of solitary diaphyseal tibial metachronous metastasis from RCC in a 54-year-old male that appeared 8 years after nephrectomy without any previous evidence of disease. He underwent segmental skeletal resection, intercalary allograft over locked reamed intramedullary nailing, and soleus flap coverage. Thirty months later he presented with hardware failure and nonunion at the distal part of the allograft site. He was successfully treated with exchange nailing, fibular osteotomy, and bone grafting, showing excellent clinical and radiological outcome without any evidence of recurrence 5 years after the index operation. CONCLUSIONS Wide resection and biological reconstruction using intramedullary nailing and incorporated allograft is a good option for metachronous solitary RCC tumors.

Biomechanical Analysis of a Novel Intercalary Prosthesis for Humeral Diaphyseal Segmental Defect Reconstruction

OBJECTIVE

To study the biomechanical properties of a novel modular intercalary prosthesis for humeral diaphyseal segmental defect reconstruction, to establish valid finite element humerus and prosthesis models, and to analyze the biomechanical differences in modular intercalary prostheses with or without plate fixation.

METHODS

Three groups were set up to compare the performance of the prosthesis: intact humerus, humerus-prosthesis and humerus-prosthesis-plate. The models of the three groups were transferred to finite element software. Boundary conditions, material properties, and mesh generation were set up for both the prosthesis and the humerus. In addition, 100 N or 2 N.m torsion was loaded to the elbow joint surface with the glenohumeral joint surface fixed. Humeral finite element models were established according to CT scans of the cadaveric bone; reverse engineering software Geomagic was used in this procedure. Components of prosthetic models were established using 3-D modeling software Solidworks. To verify the finite element models, the in vitro tests were simulated using a mechanical testing machine (Bionix; MTS Systems Corporation, USA). Starting with a 50 N preload, the specimen was subjected to 5 times tensile (300 N) and torsional (5 N.m) strength; interval time was 30 min to allow full recovery for the next specimen load. Axial tensile and torsional loads were applied to the elbow joint surface to simulate lifting heavy objects or twisting something, with the glenohumeral joint surface fixed.

RESULTS

Stress distribution on the humerus did not change its tendency notably after reconstruction by intercalary prosthesis whether with or without a plate. The special design which included a plate and prosthesis effectively diminished stress on the stem where aseptic loosening often takes place. Stress distribution major concentrate upon two stems without plate addition, maximum stress on proximal and distal stem respectively diminish 27.37% and 13.23% under tension, 10.66% and 11.16% under torsion after plate allied.

CONCLUSION

The novel intercalary prosthesis has excellent ability to reconstruct humeral diaphyseal defects. The accessory fixation system, which included a plate and prosthesis, improved the rigidity of anti-tension and anti-torsion, and diminished the risk of prosthetic loosening and dislocation. A finite element analysis is a kind of convenient and practicable method to be used as the confirmation of experimental biomechanics study.

Reconstruction of Humeral Shaft Defect with an Intercalary Endoprosthesis Following Resection of Tumor

Diaphyseal defects in long bones of extremities following segmental resection are very common in the clinic, and reconstruction remains a great challenge. Although there are many treatments for diaphyseal defects at present, reconstruction with an intercalary endoprosthesis may be an optimal method. We demonstrate a surgical technique for reconstruction of a humeral shaft defect with an intercalary endoprosthesis following tumor resection, and achieve a good clinical outcome. We conclude that in comparison with other methods, reconstruction with an intercalary endoprosthesis is simple, effective, and allows for earlier weight bearing and more rapid restoration of function.

Flexural and torsional properties of a glass fiber-reinforced composite diaphyseal bone model with multidirectional fiber orientation

Although widely used, metallic implants have certain drawbacks in reconstructive bone surgery. Their high stiffness in respect to cortical bone can lead to complications which include periprosthetic fractures and aseptic loosening. In contrast to metallic alloys, fiber-reinforced composites (FRC) composed of a thermoset polymer matrix reinforced with continuous E-glass fibers have elastic properties matching those of bone. We investigated the mechanical properties of straight FRC tubes and FRC bone models representing the diaphysis of rabbit femur prepared from glass fiber/bisphenol A glycidyl methacrylate (BisGMA) - triethylene glycol dimethacrylate (TEGDMA) composite in three-point bending and torsion. Three groups of straight FRC tubes with different fiber orientations were mechanically tested to determine the best design for the FRC bone model. Tube 1 consisted most axially oriented unidirectional fiber roving and fewest bidirectional fiber sleevings. Fiber composition of tube 3 was the opposite. Tube 2 had moderate composition of both fiber types. Tube 2 resisted highest stresses in the mechanical tests and its fiber composition was selected for the FRC bone model. FRC bone model specimens were then prepared and the mechanical properties were compared with those of cadaver rabbit femora. In three-point bending, FRC bone models resisted 39-54% higher maximum load than rabbit femora with similar flexural stiffness. In torsion, FRC bone models resisted 31% higher maximum torque (p < 0.001) and were 38% more rigid (p = 0.001) than rabbit femora. Glass fiber-reinforced composites have good biocompatibility and from a biomechanical perspective, they could be used even in reconstruction of segmental diaphyseal defects. Development of an implant applicable for clinical use requires further studies.

Intercalary reconstruction of femur after tumour resection: is a vascularized fibular autograft plus allograft a long-lasting solution?

Aims

After intercalary resection of a bone tumour from the femur, reconstruction with a vascularized fibular graft (VFG) and massive allograft is considered a reliable method of treatment. However, little is known about the long-term outcome of this procedure. The aims of this study were to determine whether the morbidity of this procedure was comparable to that of other reconstructive techniques, if it was possible to achieve a satisfactory functional result, and whether biological reconstruction with a VFG and massive allograft could achieve a durable, long-lasting reconstruction.

Patients and Methods

A total of 23 patients with a mean age of 16 years (five to 40) who had undergone resection of an intercalary bone tumour of the femur and reconstruction with a VFG and allograft were reviewed clinically and radiologically. The mean follow-up was 141 months (24 to 313). The mean length of the fibular graft was 18 cm (12 to 29). Full weight-bearing without a brace was allowed after a mean of 13 months (seven to 26).

Results

At final follow-up, the mean Musculoskeletal Tumor Society Score of 22 evaluable patients was 94% (73 to 100). Eight major complications, five fractures (21.7%), and three nonunions (13%) were seen in seven patients (30.4%). Revision-free survival was 72.3% at five, ten, and 15 years, with fracture and nonunion needing surgery as failure endpoints. Overall survival, with removal of allograft or amputation as failure endpoints, was 94.4% at five, ten, and 15 years.

Discussion

There were no complications needing surgical revision after five years had elapsed from surgery, suggesting that the mechanical strength of the implant improves with time, thereby decreasing the risk of complications. In young patients with an intercalary bone tumour of the femur, combining a VFG and massive allograft may result in a reconstruction that lasts a lifetime. Cite this article: Bone Joint J 2018;100-B:378-86.

Short-term outcomes of reconstruction subsequent to intercalary resection of femoral diaphyseal metastatic tumor with pathological fracture: Comparison between segmental allograft and intercalary prosthesis

Reconstruction of bone defects following femoral diaphyseal tumor resection is challenging. Segmental allograft (SA) and intercalary prosthesis (IP) are the most common reconstruction methods for femoral diaphyseal metastatic tumors with pathological fracture. However, whether the complications and functional outcomes differ between SA and IP remains unclear. To compare the clinical outcomes and complications for patients treated with SA reconstruction or IP replacement for femoral shaft tumors, 34 patients who had undergone intercalary resection for metastatic tumor with pathological fracture in the femoral diaphysis were evaluated. Of these, 18 had received SA and 16 IP. There were 11 males, and 24 females, with a mean age of 64.5±11.3 years. The most common sites of primary metastases were lung (26.5%), breast (17.6%) and liver (14.7%). The visual analog scale (VAS), implant-related complications and the Musculoskeletal Tumor Society (MSTS) scores for each patient were collected. The follow-up period for patients ranged from 2 to 27 months. At the most recent follow-up, 28 patients had succumbed to mortality, with a mean survival time of 6.9±3.7 months for the IP group and 7.4±3.0 months for the SA group. Patients with IP had a significantly shorter time to full weight bearing and hospitalization time than those who received SA (P=0.003 and P=0.002, respectively). The rates of overall complications and implant-related complications were significantly lower for IP as compared with SA (18.8 vs. 66.7%, P=0.007; 12.5 vs. 55.6%, P=0.013). The reoperation rate of the SA group was higher than that of the IP group (38.9 vs. 12.5%), however the difference between the two groups was statistically insignificant (P=0.125). MSTS scores were significantly higher for the IP group as compared with the SA group at one month after surgery (IP, 26.7±1.6 vs. SA, 20.3±1.5; P<0.05), without a significant difference at the final follow-up. There were no statistically significant differences in age, sex, length of resection, follow-up time, operative time or blood loss between the two groups. In summary, IP reconstruction may provide improved early functional outcomes and fewer early complications, particularly for patients with a shorter life expectancy due to femoral metastatic tumors with pathological fracture.

Long-term Results of Intercalary Endoprosthetic Short Segment Fixation Following Extended Diaphysectomy

Intercalary endoprosthetic reconstruction following diaphyseal resection of osseous tumors offers functional advantages through preservation of native joints adjacent to the resected defect. Use of such implants is restricted by the amount of bone available for stem fixation adjacent to the defect. This study aimed to determine whether short osseous segment fixation with acceptable outcomes and complication rate can be reliably achieved with a customized intercalary endoprosthesis following extended diaphysectomy. A retrospective review of prospectively collected data was performed on 6 patients receiving customized anchor plugs for short segment fixation with a double compressive osseointegration intercalary implant to reconstruct segmental defects. Five of the implants were augmented with cement to support fixation in metaphyseal bone. Patient age at surgery ranged from 12 to 86 years. At mean follow-up of 39 months, mean Musculoskeletal Tumor Society functional score was 26.3, with 5 of 6 patients achieving scores of 27 or greater. Stable fixation was achieved in all patients, with the shortest segment of bone 3.7 cm in length. Three mechanical implant failures requiring revision surgery occurred. No patient required revision of the entire implant, secondary adjacent joint replacement, or secondary amputation. No patient exhibited aseptic loosening, and no case was complicated by infection. Excellent functional outcomes were seen with follow-up out to 9 years. This suggests that cement-augmented double compressive osseointegration intercalary endoprosthetic reconstruction can extend the benefits of intercalary replacement to many patients who otherwise might require adjacent joint or physeal sacrifice. However, patients should be counseled on the high risk of implant failure with subsequent need for revision surgery. [Orthopedics. 2017; 40(6):e964-e970.].

Outcomes of Intercalary Prosthetic Reconstruction for Pathological Diaphyseal Femoral Fractures Secondary to Metastatic Tumors

OBJECTIVE

To evaluate the clinical outcomes and complications of segmental prosthetic reconstruction for pathological diaphyseal femoral fractures secondary to metastatic tumors.

METHODS

Between 2011 and 2015, we retrospectively evaluated 16 patients (6 men and 10 women; 64.5 ± 11.4 years old at diagnosis) who underwent prosthetic reconstruction after segmental resection of diaphyseal femoral fractures due to metastatic lesions. Visual analog scale (VAS), functional outcomes, implant-related complications, and Mean postoperative Musculoskeletal Tumor Society (MSTS) score for each patient were collected.

RESULTS

The mean length of bone defect was 10.2 ± 2.6 cm (range, 8-16 cm); follow-up was 9 ± 6.8 months (range, 2-25 months) for all patients, and 24 months (23 and 25 months) for the 2 patients still alive. At final follow-up, 14 patients were dead, indicating a mean survival of 6.9 ± 3.6 months (range, 2-14 months). Mean preoperative VAS score was 8.5 ± 1.0, which decreased to 2.5 ± 1.3 at day 2 postoperatively, indicating significant pain relief (P < 0.05). The MSTS score for lower extremities was 84.6% (range, 73%-90%). The range of motion and function of adjacent joints was within the normal limits in all cases. Three patients (33%) developed complications, including aseptic loosening because of disease progression (1), infection (1), and peri-prosthesis fracture (1).

CONCLUSION

These findings demonstrated that this approach greatly relieves pain, and yields satisfactory functional outcomes with fewer complications in patients with pathological femoral fractures secondary to metastatic tumors; however, survival was not significantly improved.

Intercalary reconstructions after bone tumor resections: a review of treatments

An intercalary reconstruction is defined as replacement of the diaphyseal portion of a long bone after segmental skeletal resection (diaphysectomy). Intercalary reconstructions typically result in superior function compared to other limb-sparing procedures as the patient's native joints above and below the reconstruction are left undisturbed. The most popular reconstructive options after segmental resection of a bone sarcoma include allografts, vascularized fibula graft, combined allograft and vascularized fibula, segmental endoprostheses, extracorporeal devitalized autograft, and segmental transport using the principles of distraction osteogenesis. This article aims to review the indications, techniques, limitations, pros and cons, and complications of the aforementioned methods of intercalary bone tumor resections and reconstructions in the context of the ever-growing, brave new field of limb-salvage surgery.

Radial Shaft Reconstruction With an Intercalary Endoprosthesis Following Resection of Metastatic Tumor

Improvements in imaging and treatment of musculoskeletal tumors have increased the variety of options for reconstruction following joint-sparing diaphyseal resection. The purpose of this case series was to show that reconstruction of malignant tumors of the radial shaft with an intercalary prosthesis may be an option for patients with segmental bone loss. Three consecutive patients underwent wide resection of the radial diaphysis followed by reconstruction with a custom intercalary prosthesis. A custom intercalary prosthesis with lap joint design was used in all 3 cases. Mean follow-up was 18 months (range, 9-25 months). All patients were weight bearing as tolerated 1 week postoperatively. At the most recent follow-up, patients' mean elbow flexion and extension arc was 137° (range, 130°-140°). At the forearm, mean supination was 60° (range, 30°-90°) and mean pronation was 70° (range, 60°-90°). At the wrist, mean palmar flexion was 80° (range, 70°-90°) and mean dorsiflexion was 80° (range, 70°-90°). All patients reported minimal to no pain and no significant functional limitations. Mean Musculoskeletal Tumor Society score was 26/30 (87%). Reconstruction with an intercalary prosthesis is a viable option for patients with metastatic disease of the radial shaft. All patients had satisfactory results and early return to function; none required return to the operating room. Possible advantages of reconstruction with an intercalary prosthesis compared with reconstruction with a bone graft or polymethylmethacrylate osteosynthesis include early return to function and minimal weight-bearing restrictions postoperatively. [Orthopedics. 2017; 40(2):e242-e247.].

Extracorporeally frozen tumour-bearing bone combined with free vascularised fibula for the intercalary reconstruction of femoral defect after resection of bony sarcoma

BACKGROUND

With the improved survival for patients with bone sarcomas, there is a trend to reconstruct intercalary femur defects using biologic techniques. This study examined whether the results of a frozen femur autograft with vascularised fibula are comparable to other reconstructive options in terms of the functional outcomes and the complications.

MATERIALS AND METHODS

Between 2008 and 2012, eight patients with bony sarcoma of the femur were subjected to reconstruction with a recycled frozen autograft combined with a vascularised fibula flap inside. The oncologic and functional results were analysed retrospectively.

RESULTS

The mean follow-up was 48.7 months (37-71). The oncologic results were continuously disease free in five patients; there was no evidence of disease in one, one patient was alive with disease and another died of the disease. The average length of defect was 13.6 cm (9-21). Bone union was achieved in all cases. The mean time to bone union was 7.9 months (5-19) and to full weight bearing was 7.8 months (6-11). There was no infection or construct fracture in this series. Two complications were observed. One tumour recurrence in soft tissue was treated with reresection. One tibia fracture was successfully managed with cast immobilisation. The average Musculoskeletal Tumor Society functional score was 95% (27-30). The construct was intact in all patients.

CONCLUSIONS

Vascularised fibular flap combined with frozen autografts is a dependable and durable option for the reconstruction of large bony defects after femoral sarcoma resection. It had the merits of reliable bone union and low complications, which compare well with other biological reconstructions. Evidence Rating Scale for Therapeutic Studies Level IV, therapeutic study.

Outcomes of a Modular Intercalary Endoprosthesis as Treatment for Segmental Defects of the Femur, Tibia, and Humerus

BACKGROUND

Resection of diaphyseal bone tumors for local tumor control and stabilization often results in an intercalary skeletal defect and presents a reconstructive challenge for orthopaedic surgeons. Although many options for reconstruction have been described, relatively few studies report on the functional outcomes and complications of patients treated with modular intercalary endoprostheses.

QUESTIONS/PURPOSES

The objectives of this study were to examine clinical outcomes after reconstruction with a modular intercalary endoprosthesis with a specific focus on (1) the rate of complication or failure; (2) differences in complication rates by anatomic site; (3) functional results as assessed by the Musculoskeletal Tumor Society System (MSTS); and (4) differences in complication rate between patients treated with cemented versus noncemented fixation.

METHODS

We conducted a retrospective chart review of patients treated with a modular intercalary endoprosthesis from three musculoskeletal oncology centers from 2008 to 2013. The indication for use of this intercalary endoprosthesis was segmental bone loss from aggressive or malignant tumor with sparing of the joint above and below and deemed unsuitable for biologic reconstruction. No other implant was used for this indication during this period. During this period, 41 patients received a total of 44 intercalary implants, which included 18 (40%) humeri, 5 (11%) tibiae, and 21 (48%) femora. There were 27 (66%) men and 14 (34%) women with a mean age of 63 years (range, 18–91 years). Eight patients (20%) had primary bone tumors and 33 (80%) had metastatic lesions. Thirty-five (85%) patients were being operated on as an initial treatment and six (15%) for revision of a previous reconstruction. Twenty-nine (66%) procedures had cemented stem fixation and 15 (34%) were treated with noncemented fixation. The overall mean followup was 14 months (range, 1–51 months). Patients with primary tumors had a mean followup of 19 months (range, 4–48 months) and patients with metastatic disease had a mean followup of 11 months (range, 1–51 months). Causes of implant failure were categorized according to Henderson et al. [19] into five types as follows: Type I (soft tissue failure), Type II (aseptic loosening), Type III (structural failure), Type IV (infection), and Type V (tumor progression). At 2 years of followup, 38 (93%) of these patients were accounted for with three (7%) lost to followup. MSTS functional assessment was available for 39 of 41 patients (95%).

RESULTS

At latest followup of these 41 patients, 14 (34%) patients were dead of disease, two patients (5%) dead of other causes, seven (17%) are continuously disease-free, one (2%) shows no evidence of disease, and 17 (41%) are alive with disease. There were 12 (27%) nononcologic complications. Five (11%) of these were Type II failures occurring in noncemented implants between the stem and bone, and six (14%) were Type III failures occurring in cemented implants at the clamp-rod implant interface. One patient developed a deep infection (2%, Type IV failure) and underwent removal of the implant. Additionally, one patient (2%, Type V failure) was treated by amputation after local progression of his metastatic disease. Complications were more common in femoral reconstructions than in tibial or humeral reconstructions. Twelve of 21 patients (57%) with femoral reconstructions had complications versus 0% of tibial or humeral reconstructions (0 of 23; odds ratio [OR], 62; 95% confidence interval [CI], 3–1154; p < 0.0001). The mean overall MSTS score was 77%. Implants with cemented fixation (29) had higher mean MSTS scores when compared with implants with noncemented (15) fixation (84% versus 66%, p = 0.0017). The complication rate was 33% in noncemented cases and 21% in cemented cases (p = 0.39); however, Type II failure at the bone-stem interface was associated with noncemented fixation and Type III failure at the clamp-rod interface was associated with cemented fixation (OR, 143; 95% CI, 2.413–8476; p = 0.0022).

CONCLUSIONS

The results of this study indicate that this modular intercalary endoprosthesis yields equivalent results to other studies of intercalary endoprostheses in terms of MSTS scores. We found that patients treated with intercalary endoprostheses in the femur experienced more frequent complications than those treated for lesions in either the humerus or tibia and that the femoral complication rate of this endoprosthesis is higher when compared with other studies of intercalary endoprostheses for femoral reconstruction. Further studies are still needed to determine the long-term outcomes of this endoprosthesis in patients with primary tumors where longevity of the implant is of more importance than in the metastatic setting. We recommend cemented fixation for this intercalary modular endoprostheses because this provides improved MSTS scores and allows immediate return to weightbearing, which is of advantage to metastatic patients with limited lifespans. Level of Evidence: Level III, therapeutic study.

Custom-made intercalary endoprosthetic reconstruction for a parosteal osteosarcoma of the femoral diaphysis: A case report

The present report describes a case of a 44-year-old female patient who presented with a palpable mass of the left thigh. A diagnosis of parosteal osteosarcoma (POS) at the femoral diaphysis was made following a diagnostic workup. Previous reports of long bone diaphyseal POS are rare. A long diaphyseal segment of the femur containing the tumor was resected along with a healthy margin of soft tissues, and the damaged bone was reconstructed with a custom-made intercalary endoprosthesis. Subsequent pathological examination of the surgical sample confirmed the diagnosis of POS. No local recurrence or distant metastasis was observed, and the patient had a positive Musculoskeletal Tumor Society score of 28/30 (93.3%) at the 28-month post-surgery follow-up. The present study describes the clinical, radiological, and pathological features of this rare type of osteosarcoma.

Is the Induced-membrane Technique Successful for Limb Reconstruction After Resecting Large Bone Tumors in Children?

BACKGROUND

Resection of primary malignant tumors often creates large bony defects. In children, this creates reconstructive challenges, and many options have been described for limb salvage in this setting. Studies have supported the use of an induced-membrane technique after placement of a cement spacer to aid in restoration of bone anatomy.

QUESTIONS/PURPOSES

We asked: (1) What complications are associated with the induced-membrane technique? (2) How often is bone healing achieved after resection greater than 15 cm using this technique? (3) What is the functional outcome of patients treated with this technique?

METHODS

We performed a retrospective evaluation of eight patients with a mean age of 13.3 years (range, 11-17 years) treated for a malignant bone tumor between 2002 and 2012 at our centers. The primary malignant tumors involved the proximal humerus, femur, and tibia. All patients were treated using the induced-membrane technique after a resection with mean bone loss of 18 cm (range, 16-23 cm). The general indication for using the induced-membrane technique during this time was a large diaphyseal defect after resection of the tumor. In addition to using cancellous graft as with the original technique, in the current patients an autogenous nonvascularized fibula was used to enhance stability. The patients were assessed at the last followup using the Musculoskeletal Tumor Society (MSTS) scoring system. Mean followup was 47.1 months (range, 24-120 months), and none of the patients were lost to followup before 2 years.

RESULTS

A total of four unplanned reoperations were performed in these eight patients. A fracture of the reconstruction occurred in three patients and all were treated successfully, two with surgery and one with immobilization. Bone fusion was obtained in all patients within 4 to 8 months (mean, 5.6 months) after the reconstruction. The mean healing index was 0.31 month/cm of reconstruction (range, 0.23-0.5 month/cm). At last followup, the mean MSTS score was 74% (range, 67%-80%).

CONCLUSIONS

Our findings suggest that the modified induced-membrane technique is a reasonable alternative to other limb reconstruction techniques for bone tumors in children and has the advantage of not requiring a bone bank or an expensive metal prosthesis. Although more patients will be needed to substantiate our findings, it has become a standard part of our arsenal in the treatment of large bone defects after resection of pediatric primitive bone tumors.

LEVEL OF EVIDENCE

Level IV, therapeutic study.