Early Clinical and Radiological Experience with a Ceramic Bone Graft Substitute in the Treatment of Benign and Borderline Bone Lesions

Abstract Substitutes for bone grafts experience increasing popularity, but the need for defect-filling following simple curettage of benign bone lesions is controversial. In this study, we wish to objectively report the radiological changes following bone defect-filling using a composite ceramic bone graft substitute, as well as the clinical results and complications. We evaluated 35 surgically treated benign bone lesions with subsequent defect-filling using two variants of a composite ceramic bone graft substitute (CERAMENT|BONE VOID FILLER or CERAMENT|G, BONESUPPORT AB, SWEDEN). After one year, a normal cortical thickness surrounding the defect was seen in approximately 80% of patients. Inside the defect-cavity, an almost complete product-resorption was seen after one year. The most common complication was a post-operative inflammatory soft-tissue reaction, seen in 7 patients (20%), which resolved without further treatment, although short-term antibiotic treatment was initiated at a local hospital in 6 patients, due to suspected wound infection. In summary, cortical thickness most commonly normalizes after bone tumor removal and filling of the bone defect using this particular composite ceramic bone graft substitute. The ceramic substitute undergoes resorption, which causes progressive changes in the radiological appearance inside the bone defect

Oxygen conserving mitochondrial adaptations in the skeletal muscles of breath hold divers

BackgroundThe performance of elite breath hold divers (BHD) includes static breath hold for more than 11 minutes, swimming as far as 300 m, or going below 250 m in depth, all on a single breath of air. Diving mammals are adapted to sustain oxidative metabolism in hypoxic conditions through several metabolic adaptations, including improved capacity for oxygen transport and mitochondrial oxidative phosphorylation in skeletal muscle. It was hypothesized that similar adaptations characterized human BHD. Hence, the purpose of this study was to examine the capacity for oxidative metabolism in skeletal muscle of BHD compared to matched controls.MethodsBiopsies were obtained from the lateral vastus of the femoral muscle from 8 Danish BHD and 8 non-diving controls (Judo athletes) matched for morphometry and whole body VO2max. High resolution respirometry was used to determine mitochondrial respiratory capacity and leak respiration with simultaneous measurement of mitochondrial H2O2 emission. Maximal citrate synthase (CS) and 3-hydroxyacyl CoA dehydrogenase (HAD) activity were measured in muscle tissue homogenates. Western Blotting was used to determine protein contents of respiratory complex I-V subunits and myoglobin in muscle tissue lysates.ResultsMuscle biopsies of BHD revealed lower mitochondrial leak respiration and electron transfer system (ETS) capacity and higher H2O2 emission during leak respiration than controls, with no differences in enzyme activities (CS and HAD) or protein content of mitochondrial complex subunits myoglobin, myosin heavy chain isoforms, markers of glucose metabolism and antioxidant enzymes.ConclusionWe demonstrated for the first time in humans, that the skeletal muscles of BHD are characterized by lower mitochondrial oxygen consumption both during low leak and high (ETS) respiration than matched controls. This supports previous observations of diving mammals demonstrating a lower aerobic mitochondrial capacity of the skeletal muscles as an oxygen conserving adaptation during prolonged dives.</div

Low infection rate after tumor hip arthroplasty for metastatic bone disease in a cohort treated with extended antibiotic prophylaxis

Background. Compared to conventional hip arthroplasty, endoprosthetic reconstruction after tumor resection is associated with a substantially increased risk of periprosthetic joint infection (PJI), with reported rates of around 10% in a recent systematic review. The optimal duration of antibiotic prophylaxis for this patient population remains unknown. Material and Methods. To establish the infection rate associated with prolonged antibiotic prophylaxis in our department, we performed a retrospective review of all adult patients who underwent endoprosthetic reconstruction of the proximal femur after tumor resection for metastatic bone disease during a 4-year period from 2010 to 2013 (n=105 patients). Results. Intravenous antibiotic prophylaxis was administrated for an extended duration of a mean of 7.4 days. The overall infection rate was 3.6% (4/111 implants), infection free survival was 96% at 2 years, and the risk of amputation associated with infection was 25% (1/4 patients). Discussion. Preemptive eradication of bacterial contamination may be of value in certain clinical situations, where the risk level and consequences of implant-associated infection are unacceptable. Our findings suggest that extended postoperative antibiotic prophylaxis may reduce the risk of PJI in patients undergoing tumor resection and endoprosthetic replacement for metastatic bone disease associated impending or de facto pathologic fractures of the proximal femur