Retrospective, multicenter, observational study of 112 surgically treated cases of humerus metastasis.

Introduction: The humerus is the second most common site for metastasis in the peripheral skeleton. These humeral metastases (HM) occur in the midshaft in 42% to 61% of cases and theproximal humerus in 32% to 45% of cases. They are often secondary to primary breast (17-31%), kidney (13-15%) or lung (11-24%) cancer. The optimal surgical treatment between intramedullary (IM) procedures, fixation or arthroplasty is still being debated.
Hypothesis: We hypothesized that fixation and/or arthroplasty are safe and effective options for controlling pain and improving the patients' function.
Materials and Methods: Between 2004 and 2016, 11 French hospitals included 112 continuous cases of HM in 54 men (49%) and 57 women (51%). The average age was 63.7±13.4 years (30-94). The HM occurred in the context of primary breast (30%), lung (23%) or kidney (21%) cancers. The HM was proximal in 35% of cases, midshaft in 59% and distal in 7% of cases. Surgery was required in 69% of patients because of a pathological fracture. The surgical procedure consisted of bundle pinning, plate fixation, arthroplasty or locked IM nailing in 6%, 11%, 14% and 69% of patients, respectively.
Results: Seven patients (6%) had to be reoperated due to surgical site complications including two infections and four fractures (periprosthetic or away from implant). Twelve patients (11%) experienced a general complication. The overall survival was 16.7 months, which was negatively and significantly impacted by the occurrence of a fracture, a diaphyseal location and the type of primary cancer. At the final assessment, 75% had normal or subnormal function and more than 90% were pain-free or had less pain. The final function was not related to the occurrence of a fracture or etiology of the metastasis. In epiphyseal and metaphyseal HM, there was a trend to better function after shoulder arthroplasty than after plate fixation or IM nailing.
Conclusions: Our initial hypothesis was confirmed. Our findings were consistent with those of other published studies. Based on our findings, we recommend using static locked IM nailing with cementoplasty for mid-shaft lesions and modular arthroplasty for destructive epiphyseal or metaphyso-epiphyseal lesions. The criteria for assessing humeral fracture risk should be updated to allow the introduction of a preventative procedure, which contributes to better survival.
Level of Evidence: IV, retrospective study.
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