Objectives. Intramedullary fixation is considered the most stable treatment for pertrochanteric fractures of the proximal femur and cut-out is one of the most frequent mechanical complications. In order to determine the role of clinical variables and radiological parameters in predicting the risk of this complication, we analysed the data pertaining to a group of patients recruited over the course of six years. Methods. A total of 571 patients were included in this study, which analysed the incidence of cut-out in relation to several clinical variables: age; gender; the AO Foundation and Orthopaedic Trauma Association classification system (AO/OTA); type of nail; cervical-diaphyseal angle; surgical wait times; anti-osteoporotic medication; complete post-operative weight bearing; and radiological parameters (namely the lag-screw position with respect to the femoral head, the Cleveland system, the tip-apex distance (TAD), and the calcar-referenced tip-apex distance (CalTAD)). Results. The incidence of cut-out across the sample was 5.6%, with a higher incidence in female patients. A significantly higher risk of this complication was correlated with lag-screw tip positioning in the upper part of the femoral head in the anteroposterior radiological view, posterior in the latero-lateral radiological view, and in the Cleveland peripheral zones. The tip-apex distance and the calcar-referenced tip-apex distance were found to be highly significant predictors of the risk of cut-out at cut-offs of 30.7 mm and 37.3 mm, respectively, but the former appeared more reliable than the latter in predicting the occurrence of this complication. Conclusion. The tip-apex distance remains the most accurate predictor of cut-out, which is significantly greater above a cut-off of 30.7 mm. Cite this article: G. Caruso, M. Bonomo, G. Valpiani, G. Salvatori, A. Gildone, V. Lorusso, L. Massari. A six-year retrospective analysis of cut-out risk predictors in cephalomedullary nailing for pertrochanteric fractures: Can the tip-apex distance (TAD) still be considered the best parameter?. Bone Joint Res 2017;6:481–488. DOI: 10.1302/2046-3758.68.BJR-2016-0299.R1

Introduction and Objective. Trochanteric fractures are associated with increasing incidence and represent serious adverse effect of osteoporosis. Their cephalomedullary nailing in poor bone stock can be challenging and associated with insufficient implant fixation in the femoral head. Despite ongoing implant improvements, the rate of mechanical complications in the treatment of unstable trochanteric fractures is high. Recently, two novel concepts for nailing with use of a helical blade – with or without bone cement augmentation – or an interlocking screw have demonstrated advantages as compared with single screw systems regarding rotational stability and cut-out resistance. However, these two concepts have not been subjected to direct biomechanical comparison so far. The aims of this study were to investigate in a human cadaveric model with low bone density (1) the biomechanical competence of cephalomedullary nailing with use of a helical blade versus an interlocking screw, and (2) the effect of cement augmentation on the fixation strength of the helical blade. Materials and Methods. Twelve osteoporotic and osteopenic femoral pairs were assigned for pairwise implantation using either short TFN-ADVANCED Proximal Femoral Nailing System (TFNA) with a helical blade head element, offering the option for cement augmentation, or short TRIGEN INTERTAN Intertrochanteric Antegrade Nail (InterTAN) with an interlocking screw. Six osteoporotic femora, implanted with TFNA, were augmented with 3 ml cement. Four study groups were created – group 1 (TFNA) paired with group 2 (InterTAN), and group 3 (TFNA augmented) paired with group 4 (InterTAN). An unstable pertrochanteric OTA/AO 31-A2.2 fracture was simulated. All specimens were biomechanically tested until failure under progressively increasing cyclic loading featuring physiologic loading trajectory, with monitoring via motion tracking. Results. T-score in groups 3 and 4 was significantly lower compared with groups 1 and 2, p=0.03. Stiffness (N/mm) in groups 1 to 4 was 335.7+/−65.3, 326.9+/−62.2, 371.5+/−63.8 and 301.6+/−85.9, being significantly different between groups 3 and 4, p=0.03. Varus (°) and femoral head rotation around neck axis (°) after 10,000 cycles were 1.9+/−0.9 and 0.3+/−0.2 in group 1, 2.2+/−0.7 and 0.7+/−0.4 in group 2, 1.5+/−1.3 and 0.3+/−0.2 in group 3, and 3.5+/−2.8 and 0.9+/−0.6 in group 4, both with significant difference between groups 3 and 4, p<=0.04. Cycles to failure and failure load (N) at 5° varus in groups 1 to 4 were 21428+/−6020 and 1571.4+/−301.0, 20611+/−7453 and 1530.6+/−372.7,21739+/−4248 and 1587.0+/−212.4, and 18622+/−6733 and 1431.1+/−336.7, both significantly different between groups 3 and 4, p=0.04. Conclusions. From a biomechanical perspective, cephalomedullary nailing of trochanteric fractures with use of helical blades is comparable to interlocking screw fixation in femoral head fragments with low bone density. Moreover, bone cement augmentation of helical blades considerably improves their fixation strength in poor bone quality

There has been evidence of association between femoral shaft fractures and prolonged bisphosphonate therapy. We present a case series of bisphosphonate-associated fractures and invaluable lessons we have learnt. Over the last three years at our unit we have collected a case series of eight patients who have had atypical femoral fractures whilst on bisphosphonate therapy. We present illustrative cases, a summary of key findings, and invaluable lessons we have learnt. There was a long period of prodromal pain for two years before incomplete fractures developed. We speculate this is a warning sign of impending fracture. This may have been prevented with screening. Between incomplete fracture and complete fracture there was a short window of one month. Five patients presented with complete fracture, and three with thigh pain +/- evidence of incomplete fracture. Of the latter group all but one went on to develop complete fractures. The one patient who did not progress died six years after diagnosis. Of those five patients who presented with initial complete fracture, three patients recall thigh pain before fracture on further questioning. Despite being diaphyseal femoral fractures, there is a higher risk of neck of femur fractures in this patient cohort (both patients with initial interlocked nails subsequently developed neck of femur fractures soon after and were revised to cephalomedullary nails). Excluding one death from unrelated cause, only one patient has signs of complete fracture healing. All other patients are still receiving follow-up (mean 490 days). Three patients reported bilateral symptoms (pain). Two had had bilateral symptoms for one year. Both had visible incomplete fractures on further radiographic scrutiny; one underwent prophylactic cephalomedullary nailing, one was managed with active surveillance. We suggest that improved pain and radiographic changes of cortical healing may be misleading and should not be relied upon. Cephalomedullary nailing is the treatment of choice in these fractures due to higher risk of neck of femur fractures in this cohort. We suggest prompt prophylactic cephalomedullary nailing when radiographic incomplete fractures are identified due to a short window before progression to complete fracture, and the need to consider contralateral prophylactic nailing in patients describing bilateral symptoms. We speculate that thigh pain is a warning sign of impending fracture and fracture-progression can be prevented with appropriate screening

Abstract. Background. Schwannomas are slow-growing, benign tumours normally originating from the Schwann cells of the nerve sheath. Intraosseous schwannoma accounts for 0.175% of primary bone tumours and extremely rare especially outside the axial skeleton. Monoclonal gammopathy has been associated with soft tissue schwannomas but never with the intraosseous variety. Presenting problem. A 55-year-old woman with a background of monoclonal gammopathy of undetermined significance (MGUS) presented with a 2-year history of right thigh pain. CT scan showed a well defined, lytic lesion with a thin peripheral rim of sclerosis in the midshaft of the femur. MRI displayed a hyperintense, well marginated and homogenous lesion. Definitive diagnosis was made based on the classical histopathological appearance of schwannoma. Clinical management. We managed our patient with local curettage and prophylactic cephalomedullary nailing on the basis of a high mirel score. Discussion. Intraosseous schwannomas are poorly understood but most commonly reported in middle-aged women. Radiologically, their differential diagnosis includes malignant bone tumours, solitary bone cysts, aneurysmal bone cysts and giant cell tumours. As a result, they are usually diagnosed incidentally on histology. Although malignant transformation is possible in soft tissue schwannomas, all intraosseous schwannomas reported to date have been benign. This case demonstrates the importance of suspecting intraosseous schwannoma as a differential diagnosis for lytic bone lesions to avoid the overtreatment of patients. We also highlight monoclonal gammopathy of undetermined significance as a potential risk factor for a poorly understood disease and make recommendations about the appropriate management of these lesions. Declaration of Interest. (b) declare that there is no conflict of interest that could be perceived as prejudicing the impartiality of the research reported:I declare that there is no conflict of interest that could be perceived as prejudicing the impartiality of the research project