RESUMO
Background: To evaluate if Hounsfield units (HU) measured on preoperative computed tomography (CT) scans at the anatomic neck of the proximal humerus correlates with intraoperative findings of the "thumb test" in assessment of bone quality in shoulder arthroplasty patients. Methods: Primary anatomic total shoulder and reverse total shoulder arthroplasty patients from 2019-2022 with an available preoperative CT scan of the operative shoulder were prospectively enrolled at a single center with 3 surgeons who perform shoulder arthroplasty. The "thumb test" was performed intraoperatively; a positive test signified "good bone." Demographic information, including prior dual x-ray absorptiometry scans, was extracted from the medical record. HU at the cut surface of the proximal humerus were calculated, as was cortical bone thickness on preoperative CT. Fracture risk assessment tool (FRAX) scores were calculated for 10-year risk of osteoporotic fracture. Results: A total of 149 patients were enrolled. Mean age was 67.6 ± 8.5 years with 69 (46.3%) being males. Patients with a negative thumb test were significantly older (72.3 ± 6.6 vs. 66.5 ± 8.6 years; P < .001) than those with a positive thumb test. Males were more likely to have a positive thumb test than females (P = .014). Patients with a negative thumb test had significantly lower HUs on preoperative CT (16.3 ± 29.7 vs. 51.9 ± 35.2; P < .001). Patients with a negative thumb test had a higher mean FRAX score (14.1 ± 7.9 vs. 8.0 ± 4.8; P < .001). Receiver operator curve analysis was performed to identify a cut-off value for CT HU of 36.67, above which the thumb test is likely to be positive. Furthermore, receiver operator curve analysis also identified optimal cut-off values for 10-year risk of fracture by FRAX score of 7.75 HU, below which the thumb test is likely to be positive. Fifty patients were at high risk based on FRAX and HU; surgeons classified 21 (42%) as having "poor bone" quality through a negative thumb test. High-risk patients had a negative thumb test 33.8% (23/68) and 37.1% (26/71) of the time for HU and FRAX, respectively. Conclusions: Surgeons are poor at identifying suboptimal bone quality at the anatomic neck of the proximal humerus based on intraoperative thumb test when referencing against CT HU and FRAX scores. The objective measures of CT HU and FRAX scoring may be useful metrics to incorporate into surgeons' preoperative plans for humeral stem fixation using readily available imaging and demographic data.
RESUMO
Background: Acquired hemophilia A (AHA) is a disease caused by antibody formation inhibiting the function of factor VIII, causing bleeding. Recombinant porcine factor VIII (rpFVIII) escapes human FVIII antibody recognition and can provide life-saving hemostasis. However, the development of antibodies against pFVIII can limit its use. We report two cases in which loss of response to rpFVIII occurred, likely because of inhibiting antibodies. In case 1, the patient achieved hemostasis but lost response to rpFVIII within a few days. In the second case, rpFVIII controlled bleeding but the patient experienced diminishing half-life of rpFVIII infusions over time, necessitating a switch to emicizumab which provided lasting hemostasis. Key Clinical Question: Based on our experience with these cases, we reviewed the available literature regarding the use of rpFVIII in AHA. The Key Clinical Question was to determine how often inhibitors were associated with rpFVIII treatment failure. Clinical approach and conclusions: We identified 43 AHA patients across five studies who were treated with rpFVIII. Twenty-two patients (51%) developed pFVIII inhibitors and seven cases (16%) reported loss of efficacy associated with an inhibitor. In conclusion, rpFVIII can be a life-saving therapy in AHA. However, clinicians should be aware that pFVIII antibody development can reduce the efficacy and duration of response. Recombinant pFVIII's limitations support the utility of further investigation of alternative therapies such as emicizumab in early AHA management.