Image navigation assisted joint-saving surgery for treatment of bone sarcoma around knee in skeletally immature patients

Joint-Sparing Resection around the Knee for Osteosarcoma: Long-Term Outcomes of Biologic Reconstruction with Vascularized Fibula Graft Combined with Massive Allograft

(1) Background: We aim to address the following questions. What was the complication rate of vascularized fibula graft (VFG) combined with massive allograft in patients treated with joint-sparing resection around the knee for a high-grade osteosarcoma? What was the long-term survivorship of VFG free from revision and graft removal? What were the functional results as assessed by the Musculoskeletal Tumor Society (MSTS) score? (2) Methods: 39 patients treated in our unit for osteosarcoma around the knee with intercalary resection and reconstruction with VFG combined with massive allograft were included; 26 patients underwent intercalary tibial resection, while 13 underwent intercalary femoral resection. (3) Results: Mean Follow-Up was 205 months (28 to 424). Complications that required surgery were assessed in requiring surgical revision in 19 patients (49%) after a mean of 31 months (0 to 107), while VFG removal was necessary in three patients (8%). The revision-free survival of the reconstructions was 59% at 5 years and 50% at 10 to 30 years. The overall survival of the reconstructions was 95% at 5 to 15 years and 89% at 20 to 30 years. The mean MSTS score was 29.3 (23 to 30). (4) Conclusions: VFG represents an effective reconstructive option after joint-sparing intercalary resection around the knee for osteosarcoma.

The role of imaging in extremity sarcoma surgery

The surgical management of extremity bone and soft tissue sarcomas has evolved significantly over the last 50 years. The introduction and refinement of high-resolution cross-sectional imaging has allowed accurate assessment of anatomy and tumor extent, and in the current era more than 90% of patients can successfully undergo limb-salvage surgery. Advances in imaging have also revolutionized the clinician's ability to assess treatment response, detect metastatic disease, and perform intraoperative surgical navigation. This review summarizes the broad and essential role radiology plays in caring for sarcoma patients from diagnosis to post-treatment surveillance. Present evidence-based imaging paradigms are highlighted along with key future directions.

What to choose in bone tumour resections? Patient specific instrumentation versus surgical navigation: a systematic review

Patient specific instrumentation (PSI) and intraoperative surgical navigation (SN) can significantly help in achieving wide oncological margins while sparing bone stock in bone tumour resections. This is a systematic review aimed to compare the two techniques on oncological and functional results, preoperative time for surgical planning, surgical intraoperative time, intraoperative technical complications and learning curve. The protocol was registered in PROSPERO database (CRD42023422065). 1613 papers were identified and 81 matched criteria for PRISMA inclusion and eligibility. PSI and SN showed similar results in margins (0-19% positive margins rate), bone cut accuracy (0.3-4 mm of error from the planned), local recurrence and functional reconstruction scores (MSTS 81-97%) for both long bones and pelvis, achieving better results compared to free hand resections. A planned bone margin from tumour of at least 5 mm was safe for bone resections, but soft tissue margin couldn't be planned when the tumour invaded soft tissues. Moreover, long osteotomies, homogenous bone topology and restricted working spaces reduced accuracy of both techniques, but SN can provide a second check. In urgent cases, SN is more indicated to avoid PSI planning and production time (2-4 weeks), while PSI has the advantage of less intraoperative using time (1-5 min vs 15-65 min). Finally, they deemed similar technical intraoperative complications rate and demanding learning curve. Overall, both techniques present advantages and drawbacks. They must be considered for the optimal choice based on the specific case. In the future, robotic-assisted resections and augmented reality might solve the downsides of PSI and SN becoming the main actors of bone tumour surgery.

A classification system of joint-salvage tumor resection in osteosarcoma of the knee: A retrospective cohort study

BACKGROUND

Joint-preserving surgery is possible for patients with juxta-articular osteosarcoma of the knee, even when the tumor invades the epiphysis. Oncologic and functional outcomes may vary due to the extent of tumor invasion, the amount of epiphysis preservation, and reconstruction methods. We aimed to introduce a novel classification facilitating clinical evaluation of different surgical treatments.

METHODS

We identified 52 patients with osteosarcoma of the knee undergoing joint-preserving tumor resection and intercalary reconstruction. We classified procedures into two types and six subtypes based on the tumor location and adjuvant treatment employed. Oncologic outcomes, limb function and complications were compared among different types.

RESULTS

None of the patients had a local recurrence in the preserved epiphysis apart from three (5.7 %) who had local recurrence in soft tissue. Overall survival rate of the patients was 82.7 % at 5 and 10 years. There was no difference in survival rate (P = 0.909), local recurrence (P = 0.642) between type I (tumor not invading epiphysis) and type II (tumor invading epiphysis). In addition to one skin necrosis in the 3D-printed prosthesis reconstruction and one infection in Capanna reconstruction, all complications necessitating additional surgery occurred in allograft. The Musculoskeletal Tumor Society (MSTS) scores ranged from 21 to 30 with a median of 26. There were differences in the MSTS scores among six subgroups (P = 0.015), with the highest in type Ia and the lowest in type IIc. The less of the viable epiphysis retained, the worse the knee function was at long-term follow up.

CONCLUSIONS

The suggested classification can guide surgical strategy and is convenient for comparison of the functional results.

Automatic Registration and Error Color Maps to Improve Accuracy for Navigated Bone Tumor Surgery Using Intraoperative Cone-Beam CT

Computer-assisted surgery (CAS) can improve surgical precision in orthopaedic oncology. Accurate alignment of the patient’s imaging coordinates with the anatomy, known as registration, is one of the most challenging aspects of CAS and can be associated with substantial error. Using intraoperative, on-the-table, cone-beam computed tomography (CBCT), we performed a pilot clinical study to validate a method for automatic intraoperative registration.

Oncological and Functional Outcomes in Joint-sparing Resections of the Proximal Femur for Malignant Primary Bone Tumors

BACKGROUND

Joint-sparing resections (JSR) of the proximal femur allow for preservation of the proximal femoral growth plate and native hip joint, but whether this offers fewer complications or better function and longevity of the reconstruction remains unknown. In this study, we compared the functional outcomes of pediatric patients with bone sarcomas undergoing JSR of the proximal femur with intercalary allograft (ICA) reconstruction to those undergoing proximal femoral resections (PFR) with allograft-prosthetic composite (APC) reconstructions.

METHODS

We retrospectively reviewed all patients undergoing JSR with ICA reconstruction and PFR with APC reconstructions between 1995 and 2013 at a tertiary pediatric referral center. Primary outcomes included major and minor complications and secondary outcomes included the need for a secondary procedure, presence of local or distant relapse, survival status, and the presence of pain and ambulatory status (limp, assistive device, highest level of function). We assessed differences in outcomes using the Fisher exact and Wilcoxon rank-sum tests.

RESULTS

Eight patients underwent a JSR and ICA reconstruction, while 7 patients underwent a PFR with APC reconstruction. Median patient follow-up was 60.4 months (interquartile range: 36.8 to 112.9) Patients undergoing JSR and ICA reconstruction were younger than patients undergoing PFR with APC reconstruction (7.7 vs. 11.7 y, P=0.043); however, we found no other statistically significant differences in patient demographics. There were no statistically significant differences in primary or secondary outcomes between the study groups; however, patients who underwent JSR with ICA had more major complications (62.5% vs. 42.9%, P=0.29) and a lower rate of minor complications (25% vs. 28.6%, P=0.22).

CONCLUSION

Treatment of proximal femoral bone sarcomas in pediatric and adolescent patients remains a challenging enterprise. JSR with ICA reconstruction in the proximal femur, when feasible, may provide a similar function and risk of intermediate-term major and minor complications when compared with PFR with APC reconstruction. Further long-term studies are required to determine the impact of the native femoral head retention with respect to revision rates.

LEVEL OF EVIDENCE

Level III, retrospective comparative study.

Cryoablation-aided joint retention surgery for epiphysis involvement in osteosarcoma compared with endoprosthetic replacement

AIMS

We have previously reported cryoablation-assisted joint-sparing surgery for osteosarcoma with epiphyseal involvement. However, it is not clear whether this is a comparable alternative to conventional joint arthroplasty in terms of oncological and functional outcomes.

METHODS

A total of 22 patients who had localized osteosarcoma with epiphyseal involvement around the knee and underwent limb salvage surgery were allocated to joint preservation (JP) group and joint arthroplasty (JA) group. Subjects were followed with radiographs, Musculoskeletal Tumor Society (MSTS) score, and clinical evaluations at one, three, and five years postoperatively.

RESULTS

Patients in both groups (ten in JP and 12 in JA) did not differ in local recurrence (p ≥ 0.999) and occurrence of metastases (p ≥ 0.999). Overall survival was similar in both groups (p = 0.858). Patients in the JP group had less range of motion (ROM) of the knee (p < 0.001) and lower MSTS scores (p = 0.010) compared with those of the JA group only at one year postoperatively. There was no difference between groups either at three years for ROM (p = 0.185) and MSTS score (p = 0.678) or at five years for ROM (p = 0.687) and MSTS score (p = 0.536), postoperatively. Patients in the JA group tended to have more complications (p = 0.074). Survival of primary reconstruction in the JP group was better than that of the JA group (p = 0.030).

CONCLUSION

Cryoablation-aided joint-sparing surgery offers native joint preservation with comparable functional recovery and more durable reconstruction without jeopardizing oncological outcomes compared with conventional limb salvage surgery. Cite this article: Bone Joint J 2021;103-B(8):1421-1427.

Epiphysis Salvage Reconstruction and Associated Complications Following Tumor Resections in Skeletally Immature Patients

The purpose of this study was to discuss the epiphysis salvage reconstruction procedure outcomes and complications in skeletally immature patients. The study included 12 patients with pediatric malignant tumors (osteosarcoma, Ewing's sarcoma) located close to the epiphysis, who underwent epiphyseal-preservation surgery with vascularized fibula in the plastic surgery and orthopedics and traumatology clinic between January 2008 and November 2018. The study was designed retrospectively. Neoadjuvant and adjuvant chemotherapy was administered to all patients. None of the patients received radiotherapy. Functional evaluation was assessed using the Musculoskeletal Tumor Society (MSTS) scoring system. The patients were followed up for a mean period of 51 (21‑115) months. The mean age of patients was 10.4 (range, 5 to 15) years. Union times in the target region (epiphyseal region) and diaphyseal region were reported separately. Accordingly, the mean total union time in the target region of all patients was 7.9 months (5‑11), and the mean total union time in the diaphyseal region was 6.5 months (5‑9). According to the MSTS grading system, the mean score of the patients was 27.50 (range, 21‑30). The mean operative time was 480 (390‑540) min, the mean intraoperative blood loss was 790 (580‑1100) cc, and the mean length of hospital stay was 6 (4‑17) days. Six patients had shortness, 5 patients had delayed union, 3 patients had angular deformity, and 2 patients had infection. Epiphyseal-preservation surgery may be an alternative to other techniques used for malignant tumors located close to the growth line in skeletally immature patients. Despite the fact that this technique has plenty of complications, many of them can be successfully treated with secondary operations without leaving sequelae.

Surgical Technique and Outcome of Custom Joint-Sparing Endoprosthesis as a Reconstructive Modality in Juxta-Articular Bone Sarcoma

Background

Joint-sparing limb salvage surgery (JSLSS) is an advancement in the techniques and concepts of limb salvage surgery, which makes it possible to save not only the limb affected by malignancy but also the adjacent joint and the epiphyseal plate. In the growing child, this procedure is technically demanding due to the availability of small length of bone for implant purchase. Reconstruction options can be biological reconstruction or endoprosthesis; however, the outcome of endoprosthetic reconstruction after joint-sparing resection is not well described in the literature.

Purposes

(1) To determine the prosthesis survival rates when using customized Joint-Sparing Endoprosthesis (JSE) after juxta-articular resection of bone tumors, (2) to investigate the rates of local recurrence, (3) to evaluate the need for revision surgery, and (4) to compare the outcome of customized JSE with that of joint-sacrificing techniques.

Methods

In our study, joint sparing is defined as any procedure where a custom-made JSE is used in lieu of sacrificing the adjacent joint whenever the length of the remaining bone segment is not enough to accommodate the stem of a modular implant. Twenty-eight patients received JSE, and 31 joints were spared. Their age ranged from 4 to 55 years with a median age of 13 years. Twenty-one patients received surgery for primary reconstruction and 7 patients for revision of failed bone allograft or modular implant. Twenty-four joints are spared in the lower limbs and 7 in the upper limbs. Osteosarcoma was the most common pathological diagnosis (n = 13). Flat surface HA-coated custom JSE was used to spare 15 joints, and short-stemmed custom JSE was used to spare 16 joints. The length of the remaining bone epiphysis for JSE anchorage from the knee and ankle joints was 25-75 mm, median = 45 mm, and the length of the cortical bone remaining for the proximal femur and distal humerus was 5-70 mm, median = 10 mm.

Results

Operative time was 2.5 to 4 hours (avg. 3 hr.) The bone resection surface fitted the prosthesis surface with <2 mm difference. Histological examination of all resected specimens shows clear bone resection margins; 2 patients had positive soft tissue margins. At mean follow-up period of 3 years (6 months-10 years), 6 patients developed local and systemic recurrences, three of them had a pathological fracture at the time of diagnosis (P=0.139), and 4 showed a poor response to chemotherapy (P=0.139), and 4 showed a poor response to chemotherapy (.

Conclusions

Whenever this kind of implant is affordable and can be utilized, particularly in younger age groups, JSE may be a good reconstruction option to avoid the use of expandable implants and to avoid the potentially higher revision and complication rates associated with biological reconstruction, as well as the complications of conventional joint-sacrificing implant, mainly dislocations and polyethylene wear and tear.

The evolution of three-dimensional technology in musculoskeletal oncology

Musculoskeletal tumours pose considerable challenges for the orthopaedic surgeon during pre-operative planning, resection and reconstruction. Improvements in imaging technology have improved the diagnostic process of these tumours. Despite this, studies have highlighted the difficulties in achieving consistent resection free margins especially in tumours of the pelvis and spine when using conventional methods. Three-dimensional technology - three-dimensional printing and navigation technology - while relatively new, may have the potential to prove useful in the musculoskeletal tumour surgeon's arsenal. Three-dimensional printing (3DP) allows the production of objects by adding material layer by layer rather than subtraction from raw materials as performed conventionally. High resolution imaging, computer tomography (CT) and magnetic resonance imaging (MRI), are used to print highly complex and accurate items. Powder-based printing, vat polymerization-based printing and droplet-based printing are the common 3DP technologies applied. 3DP has been utilized pre-operatively in surgical planning and intra-operatively for patient specific instruments and custom made prosthesis. Pre-operative 3DP models transfer information to the surgeon in a concise yet exhaustive manner. Patient specific instruments are customized 3DP instruments utilized with the intention to easily replicate surgical plans. Complex musculoskeletal tumours pose reconstructive challenges and standard implants are often unable to reconstruct defects satisfactorily. The ability to use custom materials and tailor the pore size, elastic modulus and porosity of the 3DP prosthesis to be comparable to the patient's bone allows for a potential patient-specific prosthesis with unique incorporation and longevity properties. Similarly, navigation technology utilizes CT or MRI images to provides surgeons with real time intraoperative three-dimensional calibration of instruments. It has been shown to potentially allow surgeons to perform more accurate resections. These technological advancements have the potential to greatly impact the management of musculoskeletal tumours. 3D planning models, patient-specific instruments and customized 3DP implants and navigation should not be thought of as separate, but rather, patient-specific adaptation of relevant modes of application should be selected on a case-by-case basis when taking all unique factors of each case into consideration.

Navigation in Musculoskeletal Oncology: An Overview

Navigation in surgery has increasingly become more commonplace. The use of this technological advancement has enabled ever more complex and detailed surgery to be performed to the benefit of surgeons and patients alike. This is particularly so when applying the use of navigation within the field of orthopedic oncology. The developments in computer processing power coupled with the improvements in scanning technologies have permitted the incorporation of navigational procedures into day-to-day practice. A comprehensive search of PubMed using the search terms "navigation", "orthopaedic" and "oncology" yielded 97 results. After filtering for English language papers, excluding spinal surgery and review articles, this resulted in 38 clinical studies and case reports. These were analyzed in detail by the authors (GM and JS) and the most relevant papers reviewed. We have sought to provide an overview of the main types of navigation systems currently available within orthopedic oncology and to assess some of the evidence behind its use.

RECONSTRUCTION OF BONE DEFECTS AFTER TUMOR RESECTION BY AUTOAND ALLOGRAFTS (review of literature)

The problem of replacement of large bone defects resulting from segmental bone resections in patients with bone tumors is still actual in modern orthopedics. Segmental defects cause the main difficulty especially in cases of disturbance of normal biomechanics while the “gold standard” of reconstruction with bone autograft is not always possible. The reason is that the defect can be so extensive that would make it impossible to harvest necessary autobone stock. Therefore, allografts based on demineralized bone with optimal properties for osteoregeneration are used as an alternative for autograft. For certain composite materials it is possible to program the properties of future graft by changing its compound. Literature analysis revealed that the effectiveness of the allograft in combination with additional components is comparable to autograft effectiveness. Mesenchymal stem cells of both bone marrow and adipose tissue can be used as an additional component to improve osteoregeneration. It is noteworthy that the analyzed studies did not reveal the influence of stem cells on the tumor recurrence. Nevertheless, the authors support the need of further researches in this area to confirm gained results. Some authors still prefer traditional methods of bone traction despite obtaining own satisfactory results of defects reconstruction with allografts. Such opinion is based on proven effectiveness of the method, structural stability of construction during treatment period and ability to adjust the process of bone regeneration at any stage. The authors goal was to analyze publications over the recent 5 years with the results of experiments and clinical studies on the replacement of large bone defects after bone tumor resection with autoand allografts. Based on the literature analysis the authors propose a general algorithm for graft selection in replacement of large bone defects after segmental bone resections. 

What are the Oncologic and Functional Outcomes After Joint Salvage Resections for Juxtaarticular Osteosarcoma About the Knee?

BACKGROUND

Joint salvage surgery for patients with juxtaarticular osteosarcoma remains challenging, especially when the tumor invades the epiphysis. Because patients are surviving longer with current chemotherapy regimens, it is advantageous to retain native joints if possible, especially in young patients. However, the results using joint-preserving tumor resections in this context have not been well characterized.

QUESTIONS/PURPOSES

(1) What are the functional outcomes after limb salvage surgery at a minimum of 3 years? (2) What are the oncologic outcomes? (3) Is joint salvage surgery for epiphyseal tumors associated with an increased risk of local recurrence compared with metaphyseal tumors not invading the epiphysis? (4) What are the complications associated with joint salvage surgery?

METHODS

Between 2004 and 2013, we treated 117 patients with juxtaarticular osteosarcoma; of those, 43 (38%) were treated with joint salvage surgery, and 41 (95%) of the 43 patients are included in our study. The other two (5%) were lost to followup before 3 years (mean, 4.4 years; range, 3-11 years,). During the period in question, we generally performed joint salvage surgery in these patients when they had a favorable response to chemotherapy, did not have a pathologic fracture or extrusion of the tumor into the joint, and did not have a whole-epiphyseal osteolytic lesion, a large mass, or obvious neurovascular involvement. This report is a followup of an earlier study; the current study includes an additional nine patients, and additional followup of a mean of 19 months for the patients included in the earlier report. We ascertained overall survival and survival free from local recurrence which was estimated using the Kaplan-Meier method, functional status of the limb which was evaluated using the Musculoskeletal Tumor Society (MSTS)-93 scoring system, and recorded reconstructive complications including infection, fracture, skin necrosis, and nonunion. We compared oncologic and functional outcomes between patients with (n = 28) and without tumor extension to epiphysis (n =13). We also compared oncologic and functional outcomes among patients with different adjuvant treatments including microwave ablation (n = 11), cryoablation (n = 12), and navigation-assisted osteotomy (n = 5). Complications were tallied using records from our institutional database.

RESULTS

The overall Kaplan-Mayer survival rate was 82% (95% CI, 104-128 months) at 5 years. The overall Kaplan-Meier survivorship from local recurrence was 91% at 5 years (95% CI, 115-133 months). Three patients had a local recurrence, but none had local recurrence in or close to the remaining epiphysis. The MSTS scores ranged from 22 to 30 points, with a median of 28. There were no differences in survival rate, local recurrence, or MSTS scores between patients with a tumor that did not invade the epiphysis and those in whom the tumor did invade the epiphysis. There were differences in MSTS scores among patients with epiphyseal tumor extension in which different adjuvant techniques, including microwave ablation, cryoablation, and navigation-assisted osteotomy, were used. Additional surgical procedures were recorded for 10 patients (24%). Osteonecrosis of the residual epiphysis was detected 13 patients (31%).

CONCLUSIONS

Our findings suggest it is possible to salvage joints in selected patients with juxtaarticular osteosarcoma around the knee. The patients who have a favorable response to chemotherapy are the best candidates for this approach. Future studies might explore the role of adjuvant techniques of microwave ablation and cryoablation, particularly when the tumor invades the epiphysis, and whether resections can be facilitated with navigation.

LEVEL OF EVIDENCE

Level IV, therapeutic study.

Is computer navigation when used in the surgery of iliosacral pelvic bone tumours safer for the patient?

Aims

Due to the complex anatomy of the pelvis, limb-sparing resections of pelvic tumours achieving adequate surgical margins, can often be difficult. The advent of computer navigation has improved the precision of resection of these lesions, though there is little evidence comparing resection with or without the assistance of navigation. Our aim was to evaluate the efficacy of navigation-assisted surgery for the resection of pelvic bone tumours involving the posterior ilium and sacrum.

Patients and Methods

Using our prospectively updated institutional database, we conducted a retrospective case control study of 21 patients who underwent resection of the posterior ilium and sacrum, for the treatment of a primary sarcoma of bone, between 1987 and 2015. The resection was performed with the assistance of navigation in nine patients and without navigation in 12. We assessed the accuracy of navigation-assisted surgery, as defined by the surgical margin and how this affects the rate of local recurrence, the disease-free survival and the effects on peri-and post-operative morbidity.

Results

The mean age of the patients was 36.4 years (15 to 66). The mean size of the tumour was 10.9 cm. In the navigation-assisted group, the margin was wide in two patients (16.7%), marginal in six (66.7%) and wide-contaminated in one (11.1%) with no intralesional margin. In the non-navigated-assisted group; the margin was wide in two patients (16.7%), marginal in five (41.7%), intralesional in three (25.0%) and wide-contaminated in two (16.7%). Local recurrence occurred in two patients in the navigation-assisted group (22.2%) and six in the non-navigation-assisted group (50.0%). The disease-free survival was significantly better when operated with navigation-assistance (p = 0.048). The blood loss and operating time were less in the navigated-assisted group, as was the risk of a foot drop post-operatively.

Conclusion

The introduction of navigation-assisted surgery for the resection of tumours of the posterior ilium and sacrum has increased the safety for the patients and allows for a better oncological outcome. Cite this article: Bone Joint J 2017;99-B:261–6.

Does Microwave Ablation of the Tumor Edge Allow for Joint-sparing Surgery in Patients With Osteosarcoma of the Proximal Tibia?

BACKGROUND

Joint-sparing surgery of a patient's native joint for osteosarcoma likely affords better function and comparable survival. However, it sometimes is challenging to resect a juxtaarticular osteosarcoma in a way that preserves the affected epiphysis because wide margins are necessary to minimize the risk of local recurrence. If there was a method to resect a tumor close to the joint and treat a potentially positive margin to prevent recurrence, it might allow salvage of a joint that otherwise might be lost.

QUESTIONS/PURPOSES

We therefore asked (1) whether joint-preserving tumor resection could be performed for juxtaarticular osteosarcoma after microwave ablation of the tumor edge under navigation without leading to local recurrences, (2) what is the resulting function, and (3) what are the complications associated with this procedure.

METHODS

Between 2009 and 2011, we treated 11 patients who had juxtaarticular osteosarcoma of the proximal tibia (mean age, 12 years; range, 9-16 years) with joint-preserving surgery by transepiphysis tumor resection after navigation-assisted microwave ablation of the tumor edge; they were followed a minimum of 37 months (mean, 48 months; range 37-62 months), and none was lost to followup. Patients were considered eligible for this procedure if they had a distance from the tumor edge to the articular surface between 10 to 15 mm, good chemotherapy responses, no pathologic fracture and no tumor involvement of major neurovascular structures. Allograft in combination with a vascularized fibula flap was used for segmental reconstruction. We recorded local tumor control, complications, and functional outcomes using the Musculoskeletal Tumor Society score, which ranges from 0 to 30, with higher scores indicating better function.

RESULTS

There were no local recurrences. Major complications included osteonecrosis of part of the epiphysis in two patients and deep infection in one. The Musculoskeletal Tumor Society score ranged from 26 to 30 with a mean of 29.

CONCLUSIONS

In selected patients with osteosarcoma invading the epiphysis, navigated resection facilitates performing joint-sparing surgery, and in our small series, the adjuvant microwave ablation seemed to provide adequate local tumor control. Although more experience and longer followup are needed, this approach may make it possible to salvage more native joints when performing limb salvage for osteosarcoma.

LEVEL OF EVIDENCE

Level IV, therapeutic study.