Despite numerous available treatment strategies, the management of complex proximal humeral fractures remains demanding. Impaired bone quality and considerable comorbidities pose special challenges in the growing aging population. Complications after operative treatment are frequent, in particular loss of reduction with varus malalignment and subsequent screw cutout. Locking plate fixation has become a standard in stabilizing these fractures, but surgical revision rates of up to 25% stagnate at high levels. Therefore, it seems of utmost importance to select the right treatment for the right patient. This article provides an overview of available classification systems, indications for operative treatment, important pathoanatomic principles, and latest surgical strategies in locking plate fixation. The importance of correct reduction of the medial cortices, the use of calcar screws, augmentation with bone cement, double-plate fixation, and auxiliary intramedullary bone graft stabilization are discussed in detail.

BackgroundRadiation therapy is an important therapeutic element in musculoskeletal tumours, especially when encountering multiple or painful lesions. In osteolytic lesions, a surgical stabilization with implants is often required. However, metallic implants not only complicate the CT-based planning of a subsequent radiation therapy, but also have an uncontrollable dose-modulating effect in adjuvant radiotherapy. In addition, follow-up imaging and the diagnosis of local recurrences are often obscured by metallic artefacts. Radiolucent implants consisting of carbon/polyether ether ketone (CF/PEEK) therefore facilitate adjuvant radiation therapy and follow-up imaging of bone lesions. We hereby present clinical cases with application of CF/PEEK implants in orthopaedic tumour surgery.MethodsWe report a single-centre experience of three selected patients with surgical stabilization of osteolytic bone lesions using CF/PEEK implants. Detailed information about the clinical presentation, preoperative considerations, surgical procedures and postoperative results is provided for each case.ResultsOne spinal lesion (T12 vertebral body), one lesion of the upper extremity (humerus) and one of the lower extremities (tibia) were surgically stabilized with use of CF/PEEK implants. With a mean follow-up of 12 months (range 6–25 months), no adverse events were observed. Two patients received adjuvant radiotherapy. Follow-up imaging was obtained in all patients.ConclusionThe applicability of CF/PEEK implants in orthopaedic tumour surgery is good with respect to postoperative follow-up imaging, application of adjuvant radiotherapy and intraoperative handling. As a result of the unique material properties, oncological patients might particularly benefit from CF/PEEK implants.

• Cross-sectional area was used to estimate QFM size in patients with ACL-reconstruction • A high correlation coefficient exists between quadriceps CSA and volume • Best correlation was seen 25 cm above the knee joint line • A relatively large standard error of the estimate limits CSA application.

Purpose The purpose of this study was to investigate (a) whether pre-operative serum CRP is a predictor of survival in patients with high-grade osteosarcoma, (b) whether postoperative infection is a predictor of survival in these patients and (c) whether CRP is a predictor of postoperative infection, and especially deep prosthetic infection. Methods In this retrospective single-centre study, preoperative serum CRP levels in 79 patients (37 females, 42 males; average age, 18 years; mean follow-up, 46 months) undergoing resection of an osteosarcoma were correlated with clinical data and survival. Results The mean pre-operative serum CRP level of all 79 patients was 0.53 mg/dl (SD, 1.27 mg/dl). Patients dying of their underlying disease had significantly higher CRP levels compared to patients surviving throughout the follow-up period (1.09 mg/dl ± 2.02 mg/dl versus 0.32 mg/dl ± 0.75 mg/dl, respectively; p=0.015). CRP levels were significantly correlated with survival (Pearson's correlation coefficient= −0.25; p =0.026) and histological subtype (Pearson's correlation coefficient=−0.42; p<0.001), but not with sex, age, histological response, tumour size or metastatic disease. In uni-and multivariate survival analysis, age, response to chemotherapy and serum CRP were associated with disease-specific survival. Patients with a CRP level over 1 mg/dl had a significantly lower diseasespecific five-year survival of 36.7% compared to 73.8% in patients with normal CRP values (p=0.020). Infection was not correlated with disease-specific survival. Pre-operative serum CRP levels were not correlated with post-operative infection or deep prosthetic infection. Conclusions Pre-operative serum CRP seems to be an independent predictor of survival in patients with highgrade osteosarcoma. Further studies are needed to confirm these results on a large-scale basis.