Bone Tumor Resection Research Articles

Differences in Kinematic and Kinetic Patterns According to the Bone Tumor Location after Endoprosthetic Knee Replacement Following Bone Tumor Resection: A Comparative Gait Analysis between Distal Femur and Proximal Tibia.

Modular endoprostheses are frequently used to reconstruct skeletal and knee defects from bone tumor resection and preserve joint function in patients with bone tumors around the knee. Depending on the tumor location, the muscles and extent of the tumor can vary, which can affect gait function. This study aimed to analyze kinetic and kinematic characteristics according to tumor location in patients with endoprosthetic knee replacements after bone tumor resection. Gait analyses were performed in 16 patients who underwent knee endoprosthesis due to tumors around the knee. We divided the patients into distal femur (n = 7) and proximal tibia (n = 9) groups and conducted between-group comparisons and comparisons with healthy participants. Compared with the control group, the distal femur group showed a tendency for knee extension, and the proximal tibia group showed increased maximal dorsiflexion during stance. The proximal tibia group maintained a flexed hip during the entire gait cycle, compared with the distal femur group. In summary, our results suggest a difference in gait between the distal femur and proximal tibia groups. Patients who have undergone knee prosthesis after knee tumor resection may require different rehabilitation strategies according to the tumor location.

Megaprosthesis Reconstruction of the Proximal Femur following Bone Tumour Resection: When Do We Need the Cup?

PurposeReconstruction of the proximal femur after tumour resection can be performed with proximal femoral endopros-theses (PFE). Many studies have reported that bipolar hemiarthroplasty (BHA) reduce the risk of dislocation after oncological resections. However, progressive cotyloiditis which might require acetabular resurfacing (total hip arthroplasty [THA]) has been reported. The aim of this study is to compare the results of BHA and THA after proximal femur resection.Materials and MethodsA total of 104 consecutive patients affected by primary (n=52) and metastatic (n=52) bone tumours were included. Ninety patients underwent BHA and 14 patients underwent THA. Complications were recorded and classified according to the Henderson classification. At final follow-up, patients with the implant in site were functionally evaluated with modified Harris hip score (HHS).ResultsThe mean follow-up was 50 months (range, 2–171 months). Twenty-four (23.1%) patients developed major complications. Eleven (12.2%) BHA required acetabular resurfacing. Patients affected by primary bone tumours showed an increased risk of THA conversion (P=0.042). A reduced risk was observed in patients younger than 35 years (P=0.043) and in those older than 65 years (P=0.033). Dislocation occurred in four case (3.8%), in particular after THA (P=0.021). At final follow-up, 93 patients had the prosthesis in site (80 BHA and 13 THA). Mean postoperative HHS was 70 (range, 30–90).ConclusionThe risk of dislocation is lower for bipolar endoprosthesis compared to THA. However cotyloiditis and acetabular resurfacing might occurred.

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

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. 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. 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. 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.

Outcome of Surgical Resection of Primary Malignant and Aggressive Benign Metacarpal Bone Tumors.

Primary bone tumors of the hand are relatively rare. Different treatment options have been described in case reports. In this study, the authors present the diagnostic methods and treatment strategies that they used. The goal of this study is to present the oncologic and functional outcomes of surgical resection of primary malignant and aggressive benign metacarpal bone tumors. This retrospective study included 7 patients with primary malignant and aggressive benign bone tumors of the metacarpals who underwent surgical resection with or without metacarpal reconstruction between 2000 and 2017, with a minimum follow-up of 2 years. Clinical and radiologic evaluations were reviewed, and functional evaluation was performed with the Musculoskeletal Tumor Society scoring system. Seven patients (6 female; 1 male), with a mean age of 30.9±11.3 years, were included in the study. Six tumors were de novo, whereas 1 was recurrent. After resection, 5 patients had metacarpal reconstruction. Nonvascularized fibula was used for 3 patients, extracorporeal freezing of the metacarpal using liquid nitrogen was used for 1 patient, and metacarpal shift was used for 1 patient. Mean follow-up was 52.6±26.7 months. At the final follow-up, mean Musculoskeletal Tumor Society score was 27.4±1.6, and no local recurrence was documented. One patient had chest metastasis after 8 years of follow-up. The results show that surgical resection of primary malignant and aggressive benign tumors of the metacarpal bones can achieve satisfactory functional and oncologic outcomes. [Orthopedics. 2021;44(5):e633-e638.].

Technique and results after immediate orthotopic replantation of extracorporeally irradiated tumor bone autografts with and without fibular augmentation in extremity tumors

BackgroundReconstruction of the skeletal defects resulting from the resection of bone tumors remains a considerable challenge and one of the possibilities is the orthotopic replantation of the irradiated bone autograft. One technical option with this technique is the addition of a vital autologous fibular graft, with or without microvascular anastomosis. The aim of our study was to evaluate the clinical results of the treatment of our patient cohort with a specific view to the role of fibular augmentation.MethodsTwenty-one patients with 22 reconstructions were included. In all cases, the bone tumor was resected with wide margins and in 21 of them irradiated with 300 Gy. In the first case, thermal sterilization in an autoclave was used. The autograft was orthotopically replanted and stabilized with plates and screws. Fifteen patients underwent an additional fibular augmentation, 8 of which received microvascular anastomoses or, alternatively, a locally pedicled fibular interposition.Resultsthe most common diagnosis was a Ewing sarcoma (8 cases) and the most common location was the femur (12 cases). The mean follow-up time was 70 months (16–154 months). For our statistical analysis, the one case with autoclave sterilization and 3 patients with tumors in small bones were excluded. During follow-up of 18 cases, 55.6% of patients underwent an average of 1.56 revision surgeries. Complete bony integration of the irradiated autografts was achieved in 88.9% of cases after 13.6 months on average. In those cases with successful reintegration, the autograft was shorter (n.s.). Microvascular anastomosis in vascularized fibular strut grafts did not significantly influence the rate of pseudarthrosis.Conclusionsthe replantation of extracorporeally irradiated bone autografts is an established method for the reconstruction of bone defects after tumor resection. Our rate of complications is comparable to those of other studies and with other methods of bone reconstruction (e.g. prosthesis). In our opinion, this method is especially well suited for younger patients with extraarticular bone tumors that allow for joint preservation. However, these patients should be ready to accept longer treatment periods.

Implantation of Human-Induced Pluripotent Stem Cell-Derived Cartilage in Bone Defects of Mice.

Although bone has an innate capacity for repair, clinical situations such as comminuted fracture, open fracture, or the surgical resection of bone tumors produce critical-sized bone defects that exceed the capacity and require external intervention. Initiating endochondral ossification (EO) by the implantation of a cartilaginous template into the bone defect is a relatively new approach to cure critical-sized bone defects. The combination of chondrogenically primed mesenchymal stromal/stem cells and artificial scaffolds has been the most extensively studied approach for inducing endochondral bone formation in bone defects. In this study, we prepared cartilage (human-induced pluripotent stem [hiPS]-Cart) from hiPS cells (hiPSCs) in a scaffoldless manner and implanted hiPS-Cart into 3.5 mm large defects created in the femurs of immunodeficient mice to examine the repair capacity. For the control, nothing was implanted into the defects. The implantation of hiPS-Cart significantly induced more new bone in the defect compared with the control. Culture periods for the chondrogenic differentiation of hiPSCs significantly affected the speed of bone induction, with less time resulting in faster bone formation. Histological analysis revealed that hiPS-Cart induced new bone formation in a manner resembling EO of the secondary ossification center, with the cartilage canal, which extended from the periphery to the center of hiPS-Cart, initially forming in unmineralized cartilage, followed by chondrocyte hypertrophy at the center. In the newly formed bone, the majority of osteocytes, osteoblasts, and adipocytes expressed human nuclear antigen (HNA), suggesting that these types of cells mainly derived from the perichondrium of hiPS-Cart. Osteoclasts and blood vessel cells did not express HNA and thus were mouse. Finally, integration between the newly formed bone and mouse femur was attained substantially. Although hiPS-Cart induced new bone that filled bone defects, the newly formed bone, which is a hybrid of human and mouse, had not remodeled to mature bone within the observation period of this study (28 weeks). Impact statement Although bone has an innate capacity for repair, critical-sized bone defects that exceed the capacity require external intervention. We prepared cartilage (human-induced pluripotent stem [hiPS]-Cart) from hiPS cells (hiPSCs) in a scaffoldless manner and examined whether implantation of hiPS-Cart heals critical-sized defects created in the femurs of immunodeficient mice. The implantation of hiPS-Cart induced new bone in the defect in a manner resembling endochondral bone formation of the secondary ossification center. Although hiPS-Cart induced new bone that filled bone defects, the newly formed bone, which is a hybrid of human and mouse, had not remodeled to mature bone within the observation period of this study (28 weeks).

Iliosacral Bone Tumor Resection Using Cannulated Screw-Guided Gigli Saw - A Novel Technique

BackgroundAdequate margins are technically difficult to achieve for malignant tumors involving the sacroiliac joint due to limited accessibility and viewing window. In order to address the technical difficulties faced in iliosacral tumor resection, we proposed a technique for precise osteotomy, which involved the use of canulated screws and Gigli saw (CSGS) that facilitated directional control, anteroposterior linkage of resection points and adequate surgical margins. The purpose of the current study was to evaluate whether CSGS technique facilitated sagittal osteotomy at sacral side, and were adequate surgical margins achieved? Also functional and oncological outcomes was determined along with the noteworthy complications.MethodsFrom April 2018 to November 2019, we retrospectively reviewed 15 patients who underwent resections for primary tumors of pelvis or sacrum necessitating iliosacral joint removal using the proposed CSGS technique. Chondrosarcoma was the most common diagnosis. The osteotomy site within sacrum was at ipsilateral ventral sacral foramina in 8 cases, midline of sacrum in 5 cases, and contralateral ventral sacral foramina and sacral ala with 1 case each. The average intraoperative blood loss was 3640 mL (range, 1200 and 6000 mL) with a mean operation duration of 7.4 hours (range, 5 to 12 hours). The mean follow-up was 23.0 months (range, 18 and 39 months) for alive patients.ResultsSurgical margins were wide in 12 patients (80%), wide-contaminated in 1 patient (6.7%), and marginal in 2 patients (13.3%). R0 resection was achieved in 12 (80%) patients and R1 resection in 3 patients. There were three local recurrences (20%) occurred at a mean time of 11 months postoperatively. No local recurrence was observed at sacral osteotomy. The overall one-year and three-year survival rate was 86.7% and 72.7% respectively.Complications occurred in three patients.ConclusionsThe current study demonstrated that CSGS technique for tumor resection within the sacrum and pelvis was feasible and can achieve ideal resection accuracies. The use of CSGS was associated with high likelihood of negative margin resections in the current series. Intraoperative use of CSGS appeared to be technically straightforward and allowed achievement of planned surgical margins. It is worthwhile to consider the use of CSGS technique in resection of pelvic tumors with sacral invasion and iliosacral tumors, however further follow-up at mid to long-term is warranted to observe local recurrence rate.

Free Vascularized Fibular Graft

Background: Free Vascularized Fibular Grafts (FVFGs) are currently a mainstay for extreme case reconstruction mainly due to their anatomical characteristics, reliability, and versatility in managing all bone defects cases. Method: This paper is a review article of the journal found by the author suitable for our reference in search engines with the keywords "Free Vascularized Fibular Graft" "surgery" "postoperative" and "complications". Results: FVFG can be used as management of bone defects such as post-trauma, infection or tumor, treatment of congenital abnormalities, avascular necrosis (AVN), arthrodesis, and pediatric pathology. Position Placement, Intercalary Resection, Bone Tumor Resection, Fibula Flap Retrieval, Allograft Preparation, Reconstruction at Recipient Site, and Intra-articular Resection need to be considered in the surgical procedure. Postoperative Monitoring in the ICU is necessary to evaluate Vital signs, flap viability, axle well as complications in patients. Conclusion: FVFG is a choice of bone defect reconstruction techniques with good results to be considered by orthopedic surgeons. Keywords: Free Vascularized Fibular Grafts, FVFG, Surgery post-operative, complication.

The Bateman-Type Soft Tissue Reconstruction around Proximal or Total Humeral Megaprostheses in Patients with Primary Malignant Bone Tumors-Functional Outcome and Endoprosthetic Complications.

Simple SummaryThe soft tissue reconstruction around proximal or total humeral megaprostheses following limb-sparing resection of a primary malignant bone tumor can be a challenge. A surgical technique to overcome these challenges is the Bateman-type soft tissue reconstruction, which is performed as a lateral acromion and trapezoid transfer aiming to improve soft tissue coverage and postoperative function. However, the functional outcome and the endoprosthetic complications of this procedure have hardly been evaluated. Our study shows that the Bateman-type reconstruction is a feasible treatment option, but the postoperative functional outcome is overall limited although good to excellent functional results can be achieved in individual patients. The risk for revision surgery is high within the first year, but remains low thereafter.We aimed to evaluate the functional outcome and endoprosthetic complications following the Bateman-type soft tissue reconstruction around proximal or total humeral replacements in patients undergoing resection of a primary malignant bone tumor. Between September 2001 and December 2018, a total of 102 patients underwent resection of a primary malignant bone tumor and subsequent reconstruction with a modular humeral megaprosthesis in our department. Fifteen (15%) of these patients underwent a Bateman-type soft tissue reconstruction and were included in this retrospective study. The median Musculoskeletal Tumor Society (MSTS) score was 21, the median Toronto Extremity Salvage Score (TESS) was 70, and the median American Shoulder and Elbow Surgeons (ASES) score was 72. Fifty-three percent (8/15) of all patients required a revision surgery after a median time of 6 months. There were 2 soft tissue failures, 3 infections and 3 tumor recurrences. The revision-free implant survivorship amounted to 53% (95% confidence interval (CI) 28–81) after 1 year and 47% (95% CI 22–73) at last follow-up. The Bateman-type reconstruction is a feasible option for soft tissue reconstruction but functional outcome is overall limited and the risk for revision surgery within the first postoperative year is high.

Biology and technology in the surgical treatment of malignant bone tumours in children and adolescents, with a special note on the very young.

PurposeThe main challenge in reconstruction after malignant bone tumour resection in young children remains how and when growth-plates can be preserved and which options remain if impossible.MethodsWe describe different strategies to assure best possible long-term function for young children undergoing resection of malignant bone tumours.ResultsDifferent resources are available to treat children with malignant bones tumours: a) preoperative planning simulates scenarios for tumour resection and limb reconstruction, facilitating decision-making for surgical and reconstructive techniques in individual patients; b) allograft reconstruction offers bone-stock preservation for future needs. Most allografts are intact at long-term follow-up, but limb-length inequalities and corrective/revision surgery are common in young patients; c) free vascularized fibula can be used as stand-alone reconstruction, vascularized augmentation of structural allograft or devitalized autograft. Longitudinal growth and joint remodelling potential can be preserved, if transferred with vascularized proximal physis; d) epiphysiolysis before resection with continuous physeal distraction provides safe resection margins and maintains growth-plate and epiphysis; e) 3D printing may facilitate joint salvage by reconstruction with patient-specific instruments. Very short stems can be created for fixation in (epi-)metaphysis, preserving native joints; f) growing endoprosthesis can provide for remaining growth after resection of epi-metaphyseal tumours. At ten-year follow-up, limb survival was 89%, but multiple surgeries are often required; g) rotationplasty and amputation should be considered if limb salvage is impossible and/or would result in decreased function and quality of life.ConclusionSeveral biological and technological reconstruction options must be merged and used to yield best outcomes when treating young children with malignant bone tumours.Level of EvidenceLevel V Expert opinion

Periprosthetic Stress Shielding of the Humerus after Reconstruction with Modular Shoulder Megaprostheses in Patients with Sarcoma.

(1) Background: Modular megaprosthetic reconstruction using a proximal humerus replacement has emerged as a commonly chosen approach after bone tumor resection. However, the long-term risk for revision surgery is relatively high. One factor that might be associated with mechanical failures is periprosthetic osteolysis around the stem, also known as stress shielding. The frequency, potential risk factors, and the effect on implant survival are unknown. (2) Methods: A retrospective single-center study of 65 patients with sarcoma who underwent resection of the proximal humerus and subsequent reconstruction with a modular endoprosthesis. Stress shielding was defined as the development of bone resorption around the prosthesis stem beginning at the bone/prosthesis interface. The extent of stress shielding was measured with a new method quantifying bone resorption in relation to the intramedullary stem length. All patients had a minimum follow-up of 12 months with conventional radiographs available and the median follow-up amounted to 36 months. (3) Results: Stress shielding was observed in 92% of patients (60/65). The median longitudinal extent of stress shielding amounted to 14% at last follow-up. Fifteen percent (10/65) showed bone resorption of greater than 50%. The median time to the first radiographic signs of stress shielding was 6 months (IQR 3–9). Patients who underwent chemotherapy (43/65) showed a greater extent of stress shielding compared to those without chemotherapy. Three percent (2/65) of patients were revised for aseptic loosening, and one patient had a periprosthetic fracture (1/65, 1.5%). All these cases had >20% extent of stress shielding (23–57%). (4) Conclusions: Stress shielding of the proximal humerus after shoulder reconstruction with modular megaprosthesis is common. It occurs within the first year of follow-up and might be self-limiting in many patients; however, about one third of patients shows progression beyond the first year. Still, mechanical complications were rare, but stress shielding might be clinically relevant in individual cases. The extent of stress shielding was increased in patients who underwent perioperative chemotherapy. Stress shielding can be quantified with an easy method using the stem length as a reference.

Computer-Assisted Surgical Navigation for Primary and Metastatic Bone Malignancy of the Pelvis: Current Evidence and Future Directions.

Computer-assisted navigation and robotic surgery have gained popularity in the treatment of pelvic bone malignancies, given the complexity of the bony pelvis, the proximity of numerous vital structures, and the historical challenges of pelvic bone tumor surgery. Initial interest was on enhancing the accuracy in sarcoma resection by improving the quality of surgical margins and decreasing the incidence of local recurrences. Several studies have shown an association between intraoperative navigation and increased incidence of negative margin bone resection, but long-term outcomes of navigation in pelvic bone tumor resection have yet to be established. Historically, mechanical stabilization of pelvic bone metastases has been limited to Harrington-type total hip arthroplasty for disabling periacetabular disease, but more recently, computer-assisted surgery has been employed for minimally invasive percutaneous fixation and stabilization; although still in its incipient stages, this procedure is potentially appealing for treating patients with bone metastases to the pelvis. The authors review the literature on navigation for the treatment of primary and metastatic tumors of the pelvic bone and discuss the best practices and limitations of these techniques.

2021 Canadian Spine Society Abstracts.

# Abstract 45. Determining clinically important improvement following surgery for degenerative conditions of the spine: analysis of the Canadian Spine Outcomes and Research Network (CSORN) Registry {#article-title-2} There is significant variability in clinically important improvement (CII)

A Short-Course Antibiotic Prophylaxis Is Associated with Limited Antibiotic Resistance Emergence in Post-Operative Infection of Pelvic Primary Bone Tumor Resection.

Resections of primary pelvic bone tumors are frequently complicated by surgical site infections (SSIs), thereby impairing the functional prognosis of patients, especially in case of implant removal. Although prophylactic antibiotics play an essential role in preventing SSIs, there are presently no recommendations that support their appropriate use. This study aimed to assess the impact of a 24 h prophylactic protocol on the bacterial ecology, the resistance pattern, and the SSI healing rate. We hypothesized that this protocol not only limits the emergence of resistance but also results in a good cure rate with implant retention in case of SSI. A retrospective study was performed that included all patients with an SSI following a pelvic bone tumoral resection between 2005 and 2017 who received a 24 h antibiotic prophylaxis protocol. Twenty-nine patients with an SSI were included. We observed a 75.9% rate of polymicrobial infection, with a high prevalence of digestive flora microorganisms and a majority of wild-type phenotypes. We confirmed that there was no significant emergence of resistant flora. After first-line debridement, antibiotics (DA) if any implant was used, or debridement, antibiotics, and implant retention (DAIR) whenever possible, we obtained a 79.3% cure rate, with implant removal in 20% of cases. The absence of an implant was significantly associated with SSI healing. Early infection management and low resistance profiles may also have a positive effect, but this needs to be confirmed in a larger cohort. In light of this, the use of a 24 h prophylactic protocol in primary pelvic bone tumor resections is associated with a favorable infection cure rate and implant retention in case of SSI, and minimal selection of resistant microorganisms.

Resection arthrodesis and osteoarticular allografts reconstruction after resection of primary bone tumors around the knee: Long-term clinical outcomes and prognostic factors for failure of biological reconstruction.

The biological reconstruction of the knee with osteoarticular allografts and resection arthrodesis have been reported but there has not yet been a direct comparison between both these procedures. This study aimed to identify the prognostic factors that influence failure of biological reconstruction and compared the results between both procedures. Between 1994 and 2017, we performed 92 limb-sparing procedures using resection arthrodesis (n=53) and osteoarticular allograft reconstruction (n=39) for the management of primary bone tumors around the knee. The minimum follow-up time was 2 years in both groups. The failure rate of reconstruction in the osteoarticular allograft and resection arthrodesis group was 48.7% and 39.6%, respectively (p=0.75). The mean MSTS score in the osteoarticular allograft and resection arthrodesis group was 23.7 and 21.8, respectively (p=0.01). The significant risk factor for failure after biological reconstruction was the administration of chemotherapy (p=0.001; HR=3.39; 95% CI,1.60-7.17). Patients who underwent osteoarticular allograft had a better functional outcome than those who underwent resection arthrodesis reconstruction, but clinical outcomes between the groups were comparable. Chemotherapy is a significant adverse prognostic factor for failure of biological reconstruction.

Complex Bone Tumors of the Trunk-The Role of 3D Printing and Navigation in Tumor Orthopedics: A Case Series and Review of the Literature.

The combination of 3D printing and navigation promises improvements in surgical procedures and outcomes for complex bone tumor resection of the trunk, but its features have rarely been described in the literature. Five patients with trunk tumors were surgically treated in our institution using a combination of 3D printing and navigation. The main process includes segmentation, virtual modeling and build preparation, as well as quality assessment. Tumor resection was performed with navigated instruments. Preoperative planning supported clear margin multiplanar resections with intraoperatively adaptable real-time visualization of navigated instruments. The follow-up ranged from 2–15 months with a good functional result. The present results and the review of the current literature reflect the trend and the diverse applications of 3D printing in the medical field. 3D printing at hospital sites is often not standardized, but regulatory aspects may serve as disincentives. However, 3D printing has an increasing impact on precision medicine, and we are convinced that our process represents a valuable contribution in the context of patient-centered individual care.

PTH1-34 improves devitalized allogenic bone graft healing in a murine femoral critical size defect

The treatment of large segmental defects of long bones resulting from trauma, infection, or bone tumor resections is a major challenge for orthopedic surgeons. The reconstruction of bone defects with acellular allografts can be used as an osteoconductive approach. However, devitalized allografts are associated with high rates of clinical failure as a result of poor intrinsic osteoinduction properties and a lack of further remodeling. Nevertheless, evidence suggests that due to its anabolic properties, teriparatide (PTH1-34) could be effective as an adjuvant therapy for massive allograft healing. Therefore, our goal was to investigate in a murine critical-sized defect model whether the intermittent administration of PTH1-34 improves the incorporation and revitalization of acellular structural bone allografts. Thus, a 2.5-mm critical-sized defect was established in the right femur of C57BL/6 mice, followed by the reconstruction with a devitalized cortical structural allograft. A titanium micro locking plate was applied to the anterior femoral surface and secured in place with self-tapping locking screws. Subsequently, daily doses of PTH1–34 (30, and 40 µg/kg) or saline were administered to the mice for 14 days after surgery. The mice were maintained without PTH1–34 therapy for an additional 7 days before being euthanized at 3 weeks post-surgery. Bone graft consolidation was assessed on radiographic images and by histomorphometric analysis. Additionally, to determine the frequency of osteoprogenitor cells in the bone marrow and their in vitro osteogenic capacity, stromal cells were isolated from the bone marrow of animals treated with 30 or 40 µg/kg/day of PTH1-34 following the same protocol used for the experimental animals. Our results suggest that intermittent PTH1-34 treatment at 30 µg/kg/day after femoral allograft reconstruction surgery accelerated the healing process as evidenced by new bone formation induced on endosteal and periosteal surfaces, enhanced revitalization of allogeneic graft, and increased frequency and osteogenic capacity of bone marrow stromal cells (BMSC). These findings should encourage further studies aimed at investigating the potential therapeutic use of intermittent PTH1-34, specifically with regards to the optimal dosing regimen in clinically challenging orthopedic scenarios.

The Orthopedic-Vascular Multidisciplinary Approach Improves Patient Safety in Surgery for Musculoskeletal Tumors: A Large-Volume Center Experience.

Objective: Wide-margin resection is mandatory for malignant bone and soft tissue tumors. However, this increases the complexity of resections, especially when vessels are involved. Patients in this high-risk clinical setting could be surgically treated using the multidisciplinary orthopedic-vascular approach. This study was carried out in this healthcare organization to evaluate patient safety in term of oncologic outcomes and reduction of the complication rate. Materials and Methods: We retrospectively reviewed 74 patients (37 males, 37 females; mean age 46 years, range 9–88) who underwent surgical excision for bone/soft tissue malignant tumors closely attached to vascular structures from October 2015 to February 2019. Vascular surgery consisted of isolation of at least one vessel (64 patients), bypass reconstruction (9 patients), and end-to-end anastomosis (1 patient). Mean follow-up was 27 months. Patients’ demographics, tumor characteristics, adjuvant treatments, type of orthopedic and vascular procedures, and oncologic and functional outcomes and complications were recorded. Results: Overall survival was 85% at 3 years follow-up. In total, 22 patients experienced at least one major complication requiring further surgery and 13 patients experienced at least one minor complication, whereas 17 reported deviations from the normal postoperative course without the need for pharmacological or interventional treatment. Major complications were higher in pelvic resections compared to limb-salvage procedures (p = 0.0564) and when surgical time was more than 4 h (p = 0.0364) at univariate analysis, whereas the most important multivariate independent predictors for major complications were pelvic resection (p = 0.0196) and preoperative radiotherapy (p = 0.0426). Conclusions: A multidisciplinary ortho-vascular approach for resection of malignant bone and soft tissue tumors tightly attached to important vascular structures should be considered a good clinical practice for patient safety.

Resurfaced allograft-prosthetic composite for distal femur reconstruction in children with bone tumor.

Reconstruction of the distal femur in children following resection of bone sarcoma is challenging. The main problem in children is the small size of bone and a possible limb-length discrepancy at the end of skeletal growth secondary to the loss of the physes. We reported the results of a new surgical technique for distal femur reconstruction after bone tumor resection in children. We analyzed 5 patients with distal femoral sarcomas who underwent intra-articular resection and reconstruction with resurfaced allograft-prosthetic composite at a mean follow-up of 70 months. There were 2 males and 3 females, with a mean age of 10 years (range 8-12) at the time of the diagnosis. All patients were affected by high-grade osteosarcoma. The patients' medical records were reviewed for clinical and functional outcomes as well as post-operative complications. The functional evaluation of the patients was done at the end of the follow-up using Musculoskeletal Tumor Society scoring system. The minimal follow-up was 24 months. At the last follow-up, 4 patients were continuously disease-free. We excluded one patient who died of disease secondary to lung metastases 16 months after the surgery. Complications occurred in 2 of 4 patients at 17 months and 24 months, respectively. One patient developed deep infection who required the removal of the original reconstruction and, once the infection was treated, the patient underwent reconstruction with an expandable prosthesis. An allograft fracture occurred in another of the 4 patients at 24 months after the first surgery, thus the original reconstruction was removed and the patient underwent reconstruction with modular prosthesis. In the two patients who retained the original reconstruction at the time of their latest follow-up, the mean implant survival time was 70 months. These patients had an excellent MSTS score (29.5 points) and walked without support or limitations with an active knee range of motion of > 90° and complete active extension of the knee. No degenerative changes of the articular surface of the proximal tibia and the patella were observed at the time of the last follow-up. Growth of the physis of the proximal tibia was observed in all the patients during follow-up and no angular deformity of the joint was observed. The limb discrepancy was 4 cm and 2 cm, respectively. Resurfaced allograft-prosthetic composite may represent an alternative surgical technique for distal femur reconstruction in children with bone sarcomas. Although its success is limited by high risk of complications, resurfaced allograft-prosthetic composite seems to be a viable option to preserve the bone stock and the physis of the proximal tibia in selected young patients, minimizing a potential limb-length discrepancy at the end of the skeletal growth.

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

IntroductionThe 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. MethodsWe 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. ResultsNonunion 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%)]. ConclusionAseptic 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.