Reconstruction of the elbow with distal humerus endoprosthetic replacement after tumor resection: a systematic review of the literature and institutional case series.

BACKGROUND: Distal humerus replacement (DHR) is a modular endoprosthesis mainly used for bone reconstruction after resection of primary or metastatic bone lesions. Studies on DHR failure rates and postoperative functional outcomes are scarce. We sought to assess implant survival, modes of failure, and functional outcomes in patients undergoing DHR for oncologic indications. METHODS: A systematic review of the PubMed and Embase databases was performed. PRISMA guidelines were followed for this manuscript. Our study was registered on PROSPERO (457,260). Quality appraisal of included studies was conducted using the STROBE checklist. Prosthetic failure was assessed using the Henderson classification for megaprosthetic failures. We additionally performed a retrospective review of patients treated with a DHR for oncologic indications at a large tertiary care academic center. Weighted means were calculated to pool data. RESULTS: Eleven studies with a total of 162 patients met the inclusion criteria. Mean follow-up was 3.7 years (range, 1.66-8 years). Henderson type 2 failures (aseptic loosening) were the most common mode of failure, occurring in 12% of cases (range, 0%-33%). Five-year implant survival was 72% (range, 49%-93.7%). Mean postoperative Musculoskeletal Tumor Society (MSTS) score was 81.1 (range, 74-84.3). In our institutional case series, 2 out of 5 patients had DHR revision for periprosthetic fracture and aseptic loosening at 16 and 27 months after surgery, respectively. CONCLUSIONS: Distal humerus replacement is a successful reconstruction strategy for tumors of the distal humerus, with high implant survival and good to excellent functional outcomes.

What is the diagnostic accuracy of fluorescence-guided surgery for margin assessment in appendicular bone and soft tissue tumors? - A systematic review of clinical studies.

BACKGROUND: Fluorescence-guided surgery (FGS) is a novel technique to successfully assess surgical margins intraoperatively. Investigation and adoption of this technique in orthopaedic oncology remains limited. METHODS: The PRISMA guidelines were followed for this manuscript. Our study was registered on PROSPERO (380520). Studies describing the use of FGS for resection of bone and soft tissue sarcomas (STS) on humans were included. Diagnostic performance metrics (sensitivity, specificity, positive predictive value [PPV], negative predictive value [NPV] and accuracy) and margin positivity rate were the outcomes assessed. RESULTS: Critical appraisal using the Joanna Brigs Institute checklists showed significant concerns for study quality. Sensitivity of FGS ranged from 22.2 % to 100 % in three of the four studies assessing his metrics; one study in appendicular tumors in the pediatric population reported 0 % sensitivity in the three cases included. Specificity ranged from 9.38 % to 100 %. PPV ranged from 14.6 % to 70 % while NPV was between 53.3 % and 100 %. The diagnostic accuracy ranged from 21.62 % to 92.31 %. Margin positivity rate ranged from 2 % to 50 %, with six of the seven studies reporting values between 20 % and 50 %. CONCLUSIONS: FSG is a feasible technique to assess tumor margins in bone and STS. Reported performance metrics and margin positivity rates vary widely between studies due to low study quality and high heterogeneity in dying protocols. LEVEL OF EVIDENCE: Level III, diagnostic study.

Risk factors for local recurrence of upper extremity desmoid tumors.

INTRODUCTION: Upper extremity (UE) desmoid tumors are locally aggressive neoplasms with high recurrence rates. Our study sought to analyze the demographics and treatment strategies of UE desmoid tumors and identify risk factors for recurrence. MATERIALS AND METHODS: A retrospective review of 52 patients with histologically confirmed UE desmoid tumors treated at our institution between 1990 and 2015 was conducted. Survival was assessed using the Kaplan-Meier method and the Cox proportional hazards model was used for risk factor analysis. RESULTS: For the entire cohort, median age was 40 (29-47) years, 75% were female, and 48% had local recurrence. The median tumor size was 45 (15-111) cm3 on imaging. Twenty-two patients had a previous resection. The most common treatments were surgery alone (50%) and surgery with adjuvant radiotherapy (21%). Tumor size ≥5 cm and tumor volume ≥40 cm3 on imaging were associated with increased recurrence (p = 0.006 and p = 0.005, respectively). Age and sex were not associated with local recurrence. Patients with a tumor size ≥5 cm were 2.6 times more likely to present with recurrence. At the 10-year mark, a lower local recurrence-free survival was seen in patients with tumors ≥5 cm (72.2% vs. 36.3%, p = 0.042) or ≥40 cm3 (67.2% vs. 32.7%, p = 0.034). CONCLUSION: In our study, only tumor dimensions appeared to modify recurrence risk.

Outcomes of Long Bones Treated With Carbon-Fiber Nails for Oncologic Indications: International Multi-institutional Study.

BACKGROUND: Intramedullary nail fixation is commonly used for prophylactic stabilization of impending and fixation of complete pathological fractures of the long bones. However, metallic artifacts complicate imaging evaluation for bone healing or tumor progression and postoperative radiation planning. Carbon-fiber implants have gained popularity as an alternative, given their radiolucency and superior axial bending. This study evaluates incidences of mechanical and nonmechanical complications. METHODS: Adult patients (age 18 years and older) treated with carbon-fiber nails for impending/complete pathological long bone fractures secondary to metastases from 2013 to 2020 were analyzed for incidences and risk factors of mechanical and nonmechanical complications. Mechanical complications included aseptic screw loosening and structural failures of host bone and carbon-fiber implants. Deep infection and tumor progression were considered nonmechanical. Other complications/adverse events were also reported. RESULTS: A total of 239 patients were included; 47% were male, and 53% were female, with a median age of 68 (IQR, 59 to 75) years. Most common secondary metastases were related to breast cancer (19%), lung cancer (19%), multiple myeloma (18%), and sarcoma (13%). In total, 17 of 30 patients with metastatic sarcoma received palliative intramedullary nail fixation for impending/complete pathological fractures, and 13 of 30 received prophylactic nail stabilization of bone radiated preoperatively to manage juxta-osseous soft-tissue sarcomas, where partial resection of the periosteum or bone was necessary for negative margin resection. 33 (14%) patients had complications. Mechanical failures included 4 (1.7%) structural host bone failures, 7 (2.9%) implant structural failures, and 1 (0.4%) aseptic loosening of distal locking screws. Nonmechanical failures included 8 (3.3%) peri-implant infections and 15 (6.3%) tumor progressions with implant contamination. The 90-day and 1-year mortalities were 28% (61/239) and 53% (53/102), respectively. The literature reported comparable failure and mortality rates with conventional titanium treatment. CONCLUSIONS: Carbon-fiber implants might be an alternative for treating impending and sustained pathological fractures secondary to metastatic bone disease. The seemingly comparable complication profile warrants further cohort studies comparing carbon-fiber and titanium nail complications.

A PEEK into carbon fiber: A practical guide for high performance composite polymeric implants for orthopaedic oncology.

Introduction: The use of carbon fiber implants in orthopaedic oncology has increased within recent years. The most widely used type of polymer is carbon fiber polyether ether ketone (CF-PEEK). Its radiolucency enables targeted radiotherapy and artifact-free tumor surveillance, which provides major advantages over metallic hardware. We aim to summarize the unique benefits within orthopaedic oncology, clinical pitfalls, and recent advancements. Methods: Four representative patient cases from a single tertiary academic medical center were treated with carbon fiber implants (n = 2 nails, n = 2 plates) from 2021 to 2022. Results: There were no adverse events noted during intraoperative implantation or postoperative follow up. All patients reported improvements in pain and no difficulties in ambulation. There were no instances of catastrophic failure or implant loosening. Conclusion: CF implants offer a diverse array of advantages regarding its radiolucency, low scatter density, and bioinert profile. Nonetheless, further research is required to understand the long-term surgical outcomes and robustness of CF implants. Multi institutional trials could address important aspects of durability and stability over extended periods, feasibility and ease-of-use for different anatomical sites and bone quality, as well as cost-effectiveness in post-operative imaging, healthcare resource utilization, and revision rates. Providing orthopaedic surgeons with valuable insight will enable thorough clinically supported, informed decision making regarding optimal use of implants.

Titanium vs. carbon fiber-reinforced intramedullary nailing for humeral bone tumors.

BACKGROUND: Multiple techniques have been described to treat humeral diaphyseal bone tumors requiring curettage or excision. Recent studies have suggested that carbon fiber-reinforced polyetheretherketone (CFR-PEEK) intramedullary nails (IMNs) may be preferable to titanium IMNs for patients with musculoskeletal tumors due to CFR-PEEK's high tensile strength, radiolucency, a modulus of elasticity closer to native bone, and improved postoperative surveillance/radiation dosing. In this study, we describe the rate of fixation failure for both CFR-PEEK and titanium humeral IMNs when used for humeral diaphyseal bone tumors requiring curettage or excision. METHODS: This was a single-institution retrospective cohort study including 81 patients (27 CFR-PEEK and 54 titanium) treated for a humeral diaphyseal bone tumor using an IMN ± methylmethacrylate between January 2017 and December 2022. Primary outcome was revision surgery due to soft tissue complications, nonunions, structural complications such as periprosthetic fracture or IMN breakage, periprosthetic infection, tumor progression, and implant failure due to rejection or fatigue. RESULTS: No failures were observed in either patients treated with titanium nails or patients treated with CFR-PEEK not requiring curettage. Fixation failure due to implant failure was observed in 2 cases-at 214 days and 469 days after surgery-where CFR-PEEK IMN was used for stabilization after a wide segmental resection for oncologic control with a cement spacer reconstruction. In both cases, the resection was larger than 6 cm, the remaining distal humerus was less than 5 cm, and failures occurred at the interface of the residual bone and spacer. Both patients were revised using a titanium distal posterolateral humeral plate fixed with screws and cables without any subsequent complications. One additional CFR-PEEK IMN required revision surgery after 744 days due to progression of the tumor and subsequent nonunion. One revision surgery was observed after 63 days for the titanium IMN because of nonunion and tumor progression. CONCLUSIONS: Humeral diaphyseal bone tumors requiring large segmental resection with small residual bone and a large cement spacer may fail via tension due to bending forces at the distal portion. In this clinical scenario, the use of larger-diameter CFR-PEEK IMNs may be indicated when available. In the interim, use of intercalary allografts instead of cement spacers, additional fixation with a titanium plate distally, or the use of a titanium nail when using a cement spacer may be considered.

Prognostic and predictive factors in undifferentiated pleomorphic sarcoma: A long-term study from a large tertiary care urban center.

BACKGROUND AND OBJECTIVES: Undifferentiated pleomorphic sarcoma (UPS) is an aggressive type of soft tissue sarcoma (STS) with high rates of metastatic disease and local recurrence. We sought to identify risk factors for local recurrence, metastasis, and overall death, and assess their impact on overall survival (OS), local recurrence-free survival (LRFS), and metastasis-free survival (MFS). METHODS: A total of 386 cases of UPS treated at our institution from 1980 to 2020 were included. Cox proportional hazards regression was used to identifying risk factors for death, local recurrence, and/or metastasis. Using the Kaplan-Meier method, we assessed OS, LRFS, and MFS. RESULTS: Sixty-six (17%) and 121 (30%) patients with UPS developed local recurrence or metastasis, respectively. Lymph node (LN) involvement was present in 13.5% of patients. The most affected organ in patients with metastatic disease was the lungs (76.9%). Age ≥ 60 (hazard ratio [HR] = 2.42) and size ≥7 cm (HR = 1.52) were some of the significant risk factors for overall death. LN involvement was an important risk factor for both LR (HR = 2.79) and distant metastasis (HR = 5.73). CONCLUSIONS: UPS displays high rates of metastatic disease and local recurrence. Using a tumor size cutoff value of 7 cm yields superior prognostic value than the standard STS T-score thresholds. Lymphovascular invasion is an important risk factor for the development of metastasis.

Redefining Trochlear Dysplasia: Normal Thresholds Vary by Measurement Technique, Landmarks, and Sex.

BACKGROUND: Trochlear dysplasia is a known risk factor for patellar instability. Multiple radiographic measurements exist to assess trochlear morphology, but the optimal measurement technique and threshold for instability are unknown. PURPOSE: To describe the optimal measurements and thresholds for trochlear dysplasia on magnetic resonance imaging (MRI) that can identify knees with patellar instability in male and female patients. STUDY DESIGN: Cohort study (diagnosis); Level of evidence, 3. METHODS: Knee MRI scans of patients with patellar instability were compared with those of age- and sex-matched controls. Measurements of the sulcus angle, lateral trochlear inclination (LTI), and trochlear depth were performed on axial images using bony and cartilaginous landmarks. Receiver operating characteristic curve analysis was performed, with the area under the curve (AUC) describing the accuracy of each diagnostic test. Optimal cutoff values were calculated to distinguish between knees with and without patellar instability. AUC and cutoff values were reported for each measurement as well as for male and female subgroups. RESULTS: A total of 238 knee MRI scans were included in this study (138 female, 100 male; age range, 18-39 years). Trochlear depth measurements had the greatest diagnostic value, with AUCs of 0.79 and 0.82 on bone and cartilage, respectively. All measurements (sulcus angle, LTI, trochlear depth) on bone and cartilage had an AUC ≥0.7 (range, 0.70-0.86), with optimal cutoff values of 145° (bone) and 154° (cartilage) for the sulcus angle, 17° (bone) and 13° (cartilage) for LTI, and 4 mm (bone) and 3 mm (cartilage) for trochlear depth. Optimal cutoff values in female patients varied from those in male patients for all measurements except for cartilaginous trochlear depth. CONCLUSION: Normal thresholds for trochlear dysplasia varied based on the use of bony versus cartilaginous landmarks. Cartilaginous trochlear depth measurements had the greatest ability to identify knees with patellar instability. Furthermore, optimal cutoff values for all measurements except for cartilaginous trochlear depth differed between female and male patients. These findings suggest that sex-specific parameters of normal values may be needed in the assessment of risk factors for patellofemoral instability.

What Are the Functional and Surgical Outcomes of Tibial Turnup-plasty for Salvage in Patients With Chronic Lower Extremity Infection?

BACKGROUND: Tibial turnup-plasty is a rarely performed surgical option for large bone defects of the distal or entire femur and can serve as an alternative to hip disarticulation or high above-knee amputation. It entails pedicled transport of the ipsilateral tibia with or without the proximal hindfoot for use as a vascularized autograft. It is rotated 180° in the coronal or sagittal plane to the remaining proximal femur or pelvis, augmenting the functional length of the thigh. Prior reports consist of small case series with heterogeneous surgical techniques. Patient-reported outcome measures after the procedure have not been reported, and ambulatory status after the procedure is also unknown. QUESTIONS/PURPOSES: (1) What proportion of patients underwent reoperation after tibial turnup-plasty? (2) What is the ambulatory status and what proportion of patients used a prosthesis after tibial turnup-plasty? (3) What are the Patient-Reported Outcome Measurement Information System (PROMIS) Global-10 mental and physical function scores after tibial turnup-plasty? METHODS: A retrospective analysis was performed of 11 patients who underwent tibial turnup-plasty between 2003 and 2021 by a single orthopaedic oncology division in collaboration with a reconstructive plastic surgery team. Nine patients were men, with a median age of 55 years (range 34 to 75 years). All had chronic infections after arthroplasty or oncologic reconstructions, with a median number of 13 surgeries before turnup-plasty. All were considered to have no other surgical options other than hip disarticulation or high transfemoral amputation. All patients who were offered this possibility accepted it. Data of interest included patient demographics and comorbidities, surgical history that led to limb compromise, medical and surgical perioperative complications, date of prosthesis fitting, and functional capacity at the most recent follow-up interval based on ambulatory status and PROMIS Global-10 mental and physical function scores. The statistical analysis was descriptive. RESULTS: The median number of reoperations after turnup-plasty was one (range 0 to 11). Of the six patients who underwent at least one reoperation, indications for surgery included wound infection (four patients), nonunion of the osteosynthesis site (two), heterotopic ossification (one), tumor recurrence (one), and flap hypoperfusion treated with local tissue revision (one). One patient underwent conversion to external hemipelvectomy for tumor recurrence. Ten of the 11 patients were ambulatory at the final follow-up interval with standard above-knee amputation prostheses. Two ambulated unassisted, four used a single crutch or cane, and four used two crutches or a walker. Of the nine patients for whom scores were available, the median PROMIS Global-10 physical and mental health scores were 48 (range 30 to 68) and 53 (range 41 to 68), both within the standard deviation of the population mean of 50. CONCLUSION: The tibial turnup-plasty is a complex surgical option for patients with large bone defects of the femur for whom there are no alternative surgeries capable of producing residual extremities with acceptable functional length. This should be viewed as a procedure of last resort to avoid a hip disarticulation or a high transfemoral amputation in patients who have typically undergone numerous prior operations. Although ambulation with a prosthesis within 1 year can be expected, almost all patients will require an assistive device to do so, and reoperations are frequent. LEVEL OF EVIDENCE: Level IV, therapeutic study.