Fractures in bone tumour prosthesis

Revision surgery for periprosthetic fracture of distal femur after endoprosthetic replacement of knee joint following resection of osteosarcoma

Purpose

Periprosthetic fracture (PPF) is one of the severe complications in patients with osteosarcoma and carries the risk of limb loss. This study describes the characteristics, treatment strategies, and outcomes of this complication.

Methods

Patients were consecutively included who were treated at our institution between 2016 and 2020 with a PPF of distal femur. The treatment strategies included two types: 1) open reduction and internal fixation with plates and screws and 2) replacement with long-stem endoprosthesis and reinforcement with wire rope if necessary.

Results

A total of 11 patients (mean age 12.2 years (9-14)) were included, and the mean follow-up period was 36.5 (21-54) months. Most fractures were caused by direct or indirect trauma (n = 8), and others (n = 3) underwent PPF without obvious cause. The first type of treatment was performed on four patients, and the second type was performed on seven patients. The mean Musculoskeletal Tumor Society (MSTS) score was 20 (17-23). All patients recovered from the complication, and limb preservation could be achieved.

Conclusion

PPF is a big challenge for musculoskeletal oncologists, particularly in younger patients. Additionally, PPF poses a challenge for orthopedic surgeons, as limb preservation should be an important goal. Hence, internal fixation with plates and endoprosthetic replacement are optional treatment strategies based on fracture type and patient needs.

Proximal femoral replacement for non-neoplastic conditions: a systematic review on current outcomes

Proximal femoral replacement (PFR) is a well-established treatment for neoplasia of the proximal femur. The use of this surgical technique for non-neoplastic conditions has increased over the years. We carried out a systematic review of the literature to study the indications, complications, and functional results when PFR is used for non-neoplastic conditions. Twenty-seven studies were included in the review with a total of 828 PFRs with a mean follow-up of 50 months (range 1-225 months). The main indications were infection (28%), periprosthetic fracture (27%), aseptic loosening (22%), and fracture (16%). The rate of reoperation was 20.3% overall. The overall revision rate was 15.4%. The main complications were dislocation (10.2%) and infection (7.3%). After 2010, the rates of reoperation (25.5% versus 18.2%), loosening (9.4% versus 3.2%), and dislocation (15.7% versus 7.9%) were lower than before 2010. The 30-day mortality ranged from 0% to 9%. The hip function scores improved post-surgery. In conclusion, the use of PFR in non-neoplastic conditions remains a marginal tool, associated with low direct mortality and high complication rates, but we expect its use to increase in the near future.

Histone demethylase LSD1 is critical for endochondral ossification during bone fracture healing

Bone fracture is repaired predominantly through endochondral ossification. However, the regulation of endochondral ossification by key factors during fracture healing remains largely enigmatic. Here, we identify histone modification enzyme LSD1 as a critical factor regulating endochondral ossification during bone regeneration. Loss of LSD1 in Prx1 lineage cells severely impaired bone fracture healing. Mechanistically, LSD1 tightly controls retinoic acid signaling through regulation of Aldh1a2 expression level. The increased retinoic acid signaling in LSD1-deficient mice suppressed SOX9 expression and impeded the cartilaginous callus formation during fracture repair. The discovery that LSD1 can regulate endochondral ossification during fracture healing will benefit the understanding of bone regeneration and have implications for regenerative medicine.

Long-Term Risk of Venous Thromboembolism in Survivors of Childhood Cancer: A Report From the Childhood Cancer Survivor Study

Purpose To estimate the incidence of late-occurring venous thromboembolism (VTE) among survivors of childhood cancer and to identify risk factors for VTE to facilitate diagnosis and prevention. Methods The Childhood Cancer Survivor Study is a multi-institutional cohort of 24,355 5-year childhood cancer survivors (diagnosed between 1970 and 1999; median age at last follow-up, 28.7 years [range, 5.6 to 58.9 years]; median follow-up since diagnosis, 21.3 years [range, 5.0 to 39.2 years]) and 5,051 sibling participants. The primary end point was self-reported late (≥ 5 years after cancer diagnosis) VTE. Rate ratios (RRs) were estimated with multivariable piecewise exponential models. Results Late VTE incidence among survivors and siblings was 1.1 and 0.5 events per 1,000 person-years, respectively (RR, 2.2; 95% CI, 1.7 to 2.8), with 2.5 excess events per 100 survivors over 35 years. Among survivors, risk factors for VTE were female sex (RR, 1.3; 95% CI, 1.1 to 1.6), cisplatin (reference none; 1 to 199 mg/m2: RR, 3.0 [95% CI, 1.4 to 6.5]; 200 to 399 mg/m2: RR, 1.9 [95% CI, 1.0 to 3.6]; ≥ 400 mg/m2: RR, 2.0 [95% CI, 1.2 to 3.3]), l-asparaginase (RR, 1.3; 95% CI, 1.0 to 1.7), obesity or underweight (reference body mass index [BMI] 18.5 to 24.9 kg/m2; BMI ≥ 30.0 kg/m2: RR, 1.6 [95% CI, 1.2 to 2.0]; BMI < 18.5 kg/m2: RR, 2.4 [95% CI, 1.7 to 3.4]), and late cancer recurrence or subsequent malignant neoplasm (RR, 4.6; 95% CI, 3.6 to 5.8). Among lower-extremity osteosarcoma survivors, limb salvage (reference amputation; RR, 3.1; 95% CI, 1.2 to 7.5) and cisplatin 200 to 399 or ≥ 400 mg/m2 (reference none; RR, 4.0 [95% CI, 1.1 to 14.6] and 2.9 [95% CI, 1.1 to 8.0], respectively) were independently associated with late VTE. VTE was associated with increased risk for nonexternal cause late mortality (RR, 1.9; 95% CI, 1.6 to 2.3). Conclusion Childhood cancer survivors are at increased risk for VTE across their lifespan and a diagnosis of VTE increases mortality risk. Interventions that target potentially modifiable comorbidities, such as obesity, warrant consideration, with prophylaxis for high-risk survivors, including those treated with cisplatin and limb-sparing approaches.