Fracture Risk of Long Bone Metastases: A Review of Current and New Decision-Making Tools for Prophylactic Surgery.

Long bone pathological fractures very much reflect bone metastases morbidity in many types of cancer. Bearing in mind that they not only compromise patient function but also survival, identifying impending fractures before the actual event is one of the main concerns for tumor boards. Indeed, timely prophylactic surgery has been demonstrated to increase patient quality of life as well as survival. However, early surgery for long bone metastases remains controversial as the current fracture risk assessment tools lack accuracy. This review first focuses on the gold standard Mirels rating system. It then explores other unique imaging thresholds such as axial or circumferential cortical involvement and the merits of nuclear imaging tools. To overcome the lack of specificity, other fracture prediction strategies have focused on biomechanical models based on quantitative computed tomography (CT): computed tomography rigidity analysis (CT-RA) and finite element analysis (CT-FEA). Despite their higher specificities in impending fracture assessment, their limited availability, along with a need for standardization, have limited their use in everyday practice. Currently, the prediction of long bone pathologic fractures is a multifactorial process. In this regard, machine learning could potentially be of value by taking into account clinical survival prediction as well as clinical and improved CT-RA/FEA data.

High rate of fracture in long-bone metastasis: Proposal for an improved Mirels predictive score.

INTRODUCTION: Pathologic fracture is the most feared complication in long-bone metastasis. Various radiographic tools are available for identifying at-risk patients and guide preventive treatment. The Mirels score is the most frequently studied and widely used, but has been criticized, many patients not being operated on until the actual fracture stage. We therefore conducted a French national multicenter prospective study: (1) to determine the proportion of patients operated on at fracture stage versus preventively; (2) to compare Mirels score between the two; and (3) to identify factors for operation at fracture stage according to Mirels score and other epidemiological, clinical and biological criteria. HYPOTHESIS: Simple discriminatory items can be identified to as to complete the Mirels score and enhance its predictive capacity. MATERIAL AND METHODS: A non-controlled multicenter prospective study included 245 patients operated on for non-revelatory long-bone metastasis, comparing patients operated on for fracture versus preventively according to body-mass index (BMI), ASA score, Katagiri score items and the 4 Mirels items. RESULTS: One hundred and twenty-six patients (51.4%) were operated on at fracture stage: 106 (84.1%) showed high risk on Mirels score (score>8), and 15 (11.9%) moderate risk (score=8). On multivariate analysis, 4 independent factors emerged: in increasing order, advanced age (OR=1.03; 95%CI 1.01-1.06), VAS pain score>6 (OR=1.47; 95%CI 1.02-2.11), WHO grade>2 (OR=2.74; 95%CI 1.22-6.15), and upper-limb location (OR=5.26; 95%CI 2.13-12.84). DISCUSSION: The present study confirmed that more than half of patients with long-bone metastasis are operated on at actual fracture stage, in agreement with the literature. Several studies highlighted the weakness of the Mirels score as a predictive instrument. Comparison between preventive and fracture-stage surgery showed that upper-limb location, intense pain, advanced age and impaired functional status were associated with fracture-stage surgery, and should be taken into account alongside the original Mirels criteria. This improved scoring instrument remains to be validated in a prospective study. LEVEL OF EVIDENCE: IV, prospective cohort study without control group.

Surgical treatment of peri-acetabular metastatic disease: Retrospective, multicentre study of 91 THA cases.

INTRODUCTION: The occurrence of peri-acetabular metastasis (PAM) is a turning point in the progression of cancer because the disabling pain prevents the patient from walking or makes it difficult. Recent progress in controlling cancers that spread to the bone and controlling local bone destruction justify this national study. Since the data in France is incomplete or based on small studies, we analysed a multicentre retrospective cohort of patients with PAM who underwent total hip arthroplasty (THA) to evaluate 1) the clinical and radiological outcomes and 2) the factors impacting patient survival. HYPOTHESIS: The clinical outcomes, complication rate and survivorship are comparable to that of recent published studies. METHODS: Ninety-one patients (27 men, 64 women) with a mean age of 62.7±10.5 years (extremes 38 and 88) with PAM secondary to breast cancer [42 patients (46%)] or lung cancer [20 patients (22%)] underwent THA. The metastasis was the first sign of cancer in 33 cases (36%). Concurrent visceral metastases were present in 30 patients (33%), multiple peripheral bone metastasis in 48 patients (53%) and synchronous spine metastasis in 39 patients (43%). The most common construct was a cemented stem with metal reinforcement cage and cemented dual mobility cup [71 times (78%), while 85/91 had a dual mobility cup (93%)]. RESULTS: Elimination or reduction of pain was reported in 81 patients (91%). Overall walking ability was deemed normal or acceptable in 74 patients (83%). Six patients died (7%) before the end of the 3rd month. There were seven general complications (8%) including five thromboembolic events. There were 22 complications related to the surgical procedure in 20 patients (22%) that required surgical revision, including 10 surgical site infections (11%) and 3 dislocations (3%) (one concerning a dual mobility cup and 2 after single mobility cup). The median survivorship all causes combined was 19.5 months; it was 23.7 months for patients with breast cancer and 8.9 months for those with lung cancer. CONCLUSION: Despite different endpoints being used, the clinical outcomes in our study are like those in other published studies, as were the incidence of surgery-related complications and the survivorship. The recommended surgical technique is the implantation of an acetabular reinforcement cage, curettage with cement filling of osteolytic areas, dual mobility cup and cemented stem followed by radiation therapy. The role of THA versus interventional radiology procedures must still be determined. LEVEL OF EVIDENCE: IV, retrospective study without control group.