Osteoradionecrosis of the Hip, a Troublesome Complication of Radiation Therapy: Case Series and Systematic Review

How Do the Outcomes of Total Hip Arthroplasty for Oncologic Hip Reconstruction Compare With Those Performed for End-Stage Osteoarthritis?-A Propensity-Matched Cohort Study

BACKGROUND

Compared with total hip arthroplasty (THA) for end-stage osteoarthritis, poorer outcomes have been reported in THA for oncologic hip reconstruction because of resection of surrounding stabilizing structures and higher patient comorbidity profile. In a matched cohort, we sought to compare postoperative outcomes between these cohorts.

METHODS

A retrospective study of patients who underwent THA for oncologic (primary tumor or metastatic bone disease) or nononcologic (end-stage osteoarthritis) indications was conducted. The oncologic group was further subdivided into simple and complex; the latter included patients with concurrent proximal femur arthroplasty, Harrington reconstruction, and/or hemipelvectomy. Propensity-score matching based on age, sex, body mass index, and age-adjusted Charlson Comorbidity index was done. Primary outcomes were the cumulative incidence of reoperation, revision, and dislocation.

RESULTS

After propensity-score matching, 150 nononcologic and 50 oncologic THA were included. At 2 years, the oncologic THA group increased rates of reoperation (25.4% vs. 1.8%), revision (25.4% vs. 1.3%), and dislocation (10.2% vs. 0.6%) compared with the nononcologic group. At 5 years, the oncologic THA group similarly showed poorer implant survival for all metrics; differences between the groups were notable at both time points (P < 0.001). We observed no differences in reoperation, revision, and dislocation rates between the simple and complex oncologic THA subgroups (P > 0.05). The oncologic THA group showed a higher rate of 90-day overall complications and readmission, as well as higher rates of 2-year (15.7% vs. 4.8%; P = 0.01) and 5-year (35% vs. 14.1%; P = 0.001) mortality as compared with the nononcologic group.

CONCLUSION

Although oncologic THA displayed poorer outcomes than their nononcologic counterparts, oncologic THA complexity did not play a role in surgical outcomes. These findings allow for improved patient expectations regarding the differing complication profile for different orthopaedic subpopulations. Further studies are needed to determine adequate surgical techniques to mitigate the increased complication profile of oncologic patients.

Dose-Volume Constraints for Thoracic, Abdominal, and Pelvic Carbon Ion Radiotherapy: A Literature Review

BACKGROUND

Applying dose-volume constraints is extremely important in ensuring the safe use of radiotherapy. However, constraints for carbon ion radiotherapy (CIRT) have not been established yet. This review aims to summarize dose-volume constraints for thoracic, abdominal, and pelvic CIRT that have been identified through previous research based on the Japanese models for relative biological effectiveness (RBE).

RESULTS

Constraints are reported for the lungs, liver, stomach, gastrointestinal tract, rectum, sigmoid, bladder, nerves, rib, femoral head, sacrum, and skin. The constraints are classified into hard and soft to aid in determining whether priority should be given to the target coverage or organ-at-risk (OAR) sparing during treatment planning.

CONCLUSIONS

Further research is necessary to verify the applicability of the reported constraints and to identify constraints for the OARs that have not been investigated yet.

Post radiotherapy femoral head avascular necrosis

Osteonecrosis is the death of bone cells due to insufficient blood supply; radiotherapy for various underlying malignancies is one of the uncommon causes. Microvascular damage or underlying tissue fibrosis, which leads to an ischemic environment and cell death, is a proposed mechanism. Factors influencing risk of radiation induced AVN include type of radiation whether external beam radiotherapy or brachytherapy, age of the patient, included body part and concomitant additional steroid or chemotherapy treatment. In this case report we brought a case of 40-year-old male patient with right proximal thigh leiomyosarcoma who underwent surgical resection and adjuvant radiotherapy, about a year later when Pelvic MR was done for evaluation of surgical bed and tumor progress right femoral head AVN was detected, the patient was asymptomatic. The exact cut-off radiation dose that causes AVN is unknown and varies across studies, necessitating a cautious study of joints included in the radiation field even in asymptomatic patients for early diagnosis and to prevent morbidity associated with delayed diagnosis.

Clinical Outcomes Among Patients Treated With Stereotactic Body Radiation Therapy to Femur Metastases for Oligometastatic Disease Control or Reirradiation: Results From a Large Single-Institution Experience

Purpose

There are limited data regarding outcomes after stereotactic body radiation therapy (SBRT) for femur metastases, which was an exclusion criteria for the Stereotactic Ablative Radiotherapy for the Comprehensive Treatment of Oligometastatic Cancers (SABR-COMET) trial. We aimed to characterize clinical outcomes from a large single institution experience.

Methods and Materials

Forty-eight patients with 53 lesions were consecutively treated with femur SBRT from May 2017 to June 2022. The Kaplan-Meier method and Cox proportional hazard models were used to characterize time-to-event endpoints and associations between baseline factors and clinical outcomes, respectively. Local control and locoregional control were defined as the absence of tumor progression within the radiation treatment field or within the treated femur, respectively.

Results

Most patients had Eastern Cooperative Oncology Group performance status 0 to 1 (90%), prostate (52%) or breast/lung (17%) cancer, and 1 to 3 lesions (100%), including 29 proximal and 5 distal. Fifty-seven percent of the lesions were treated with concurrent systemic therapy. Median planning target volume was 49.1 cc (range, 6.6-387 cc). Planning target volume V100 (%) was 99% (range, 90-100). Fractionation included 18 to 20 Gy/1F, 27 to 30 Gy/3F, and 28.5-40 Gy/5F. Forty-two percent had Mirels score ≥7 and most (94%) did not have extraosseous extension. Acute toxicities included grade 1 fatigue (15%), pain flare (7.5%), nausea (3.8%), and decreased blood counts (1.9%). Late toxicities included fracture (1.9%) at 1.5 years and osteonecrosis (4%) from dose of 40 Gy in 5F and 30 Gy in 5F (after prior 30 Gy/10F). One patient (2%) required fixation postradiation for progressive pain. With median follow-up 19.4 months, 1- and 2-year rates of local control were 94% and 89%, locoregional control was 83% and 67%, progression-free survival were 56% and 25%, and overall survival were 91% and 73%. Fifty percent of local regional recurrence events occurred within 5 cm of gross tumor volume.

Conclusions

Femur SBRT for oligometastatic disease control in well-selected patients was associated with good outcomes with minimal rates of acute and late toxicity. Patterns of local regional recurrence warrant consideration of larger elective volume coverage. Additional prospective study is needed.

Dual Mobility for Oncological Hip Reconstruction: Significantly Reduced Dislocation Rates at 5 years

BACKGROUND

Although dual mobility total hip arthroplasty has become increasingly common in recent years, limited remains known on dual mobility in surgical oncology. This university-based investigation compared dislocation and revision rates of DMs, conventional total hip arthroplasty (THA), and hemiarthroplasties (HAs) for oncological hip reconstruction.

METHODS

An institutional tumor registry was used to identify 221 patients undergoing 45 DMs, 67 conventional THAs, and 109 HAs, performed for 17 primary hip tumors and 204 hip metastases between 2010 and 2020. The median age at surgery was 65 years, and 52% were female. The mean follow-up was 2.5 years. Kaplan-Meier survivorship curves and log-rank tests were done to compare dislocation and revision rates among all 221 patients, after a one-to-one propensity match, based on age, sex, tumor type (metastasis, primary tumor), and tumor localization (femur, acetabulum).

RESULTS

The 5-year survivorship free of dislocation was 98% in DMs, 66% in conventional THAs ( P = 0.03; all P values compared with DMs), and 97% among HAs ( P = 0.48). The 5-year survivorship free of revision was 69% in DMs, 62% in conventional THAs ( P = 0.68), and 92% in HAs ( P = 0.06). After propensity matching, the 5-year survivorship free of dislocation was 42% in 45 conventional THAs ( P = 0.027; compared with all 45 DMs) and 89% in 16 matched HAs ( P = 0.19; compared with 16 DMs with femoral involvement only). The 5-year survivorship free of revision was 40% in matched conventional THAs ( P = 0.91) and 100% in matched HAs ( P = 0.19).

CONCLUSIONS

DMs showed markedly lower rates of dislocation than conventional THAs, with overall revision rates remaining comparable among different designs. DMs should be considered the option of choice for oncological hip reconstruction if compared with conventional THAs. HAs are a feasible alternative when encountering femoral disease involvement only.

LEVEL OF EVIDENCE

III.

Application research on reducing radiation-induced lung injury with a trigger operator based on overlap volume histogram (OVH) in breast cancer postoperative radiotherapy

This study aims to develop a trigger operator based on the Overlap Volume Histogram (OVH) and examined its effectiveness in enhancing plan quality to minimize radiation-induced lung injury in postoperative radiotherapy for breast cancer. This trigger operator was applied for plan re-optimization to the previous Volumetric Modulated Arc Therapy (VMAT) plans of 16 left breast conserving surgery cases. These cases were categorized into a Contiguous Group (CG) and a Separated Group (SG) based on the relative position between the target and the Left-Lung (L-Lung). We investigated the changes in Vx, mean dose, and Normal Tissue Complication Probability (NTCP) values of organs-at-risk (OARs) before and after using the trigger operator. The Pairwise Sample T test was employed to evaluate the differences in indices between the two groups before and after optimizations. The trigger operator effectively initiated plan re-optimization. The values of V5, V10, V20, V30, and V40 of the L-Lung, as well as the mean dose of the heart, all decreased after re-optimization. The Pairwise Sample T test results showed statistically significant differences in the V20, V30, and V40 of the L-Lung in the CG (P < 0.01), and in the V5, V10, V20, V30, and V40 of the L-Lung in the SG (P < 0.01). Our findings suggest that the proposed trigger operator can improve plan quality, thereby reducing radiation-induced lung injury in postoperative radiotherapy for breast cancer.

Review of the Pathogenesis, Diagnosis, and Management of Osteoradionecrosis of the Femoral Head

Osteoradionecrosis (ORN) of the femoral head is an important issue for orthopedists and radiologists in clinical practice. With the rapid development of technological advances in radiation therapy and the improvement in cancer survival rates, the incidence of ORN is rising, and there is an unmet need for basic and clinical research. The pathogenesis of ORN is complex, and includes vascular injury, mesenchymal stem cell injury, bone loss, reactive oxygen species, radiation-induced fibrosis, and cell senescence. The diagnosis of ORN is challenging and requires multiple considerations, including exposure to ionizing radiation, clinical manifestations, and findings on physical examination and imaging. Differential diagnosis is essential, as clinical symptoms of ORN of the femoral head can resemble many other hip conditions. Hyperbaric oxygen therapy, total hip arthroplasty, and Girdlestone resection arthroplasty are effective treatments, each with their own advantages and disadvantages. The literature on ORN of the femoral head is incomplete and there is no criterion standard or clear consensus on management. Clinicians should gain a better and more comprehensive understanding on this disease to facilitate its early and better prevention, diagnosis, and treatment. This article aims to review the pathogenesis, diagnosis, and management of osteoradionecrosis of the femoral head.