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Intraoperative femoral fracture is a rare but growing complication of primary total hip arthroplasty. We aimed to present an uncommon related case, assessing also the role of malnutrition and osteoporosis. We discuss the case of a 49 years old male patient, malnourished and osteoporotic, with an intertrochanteric, multifragmentary, inveterate fracture, that happened three months before. During the prosthetic surgery, a supracondylar fracture occurred. We synthesized it with a 13 holes LISS plate, 7 distal screws and 3 proximal cerclage wires. The leg was immobilized to 0° for 3 weeks and the load forbidden for 3 months. Calcium, Albumine, Total Proteins, Osteocalcin and Vitamin-D levels were below the normal range. Teriparatide was administered for 6 months. Global investigation of the patient's nutritional status is recommended before joint replacement and preoperative planning is mandatory to choose the adequate implant. Osteoanabolic therapy could be advisable to favor fracture healing.

Background and Aim: Bone metastases are a significant prognostic factor in the history of cancer and often involve pain and a great impairment of the quality of life. The complete resection of tumor tissue is increasingly performed in patients with solitary bone metastases, to improve the survival of patients and their functional outcomes Methods: We report the case of a 65-year-old man with a painful, massive, highly perfused osteolytic lesion localized at the proximal third of the humerus, associated with extensive lesions of the rotator cuff tendons was diagnosed with keratoblastic squamous cell lung cancer metastasis., Results: The patient underwent shoulder and proximal humerus reconstruction with inverse tumor megaprosthesis after embolization of the lesion. At 3 and 6 months FU, a nearly complete resolution of painful symptoms, a significant improvement in functional skills, and better execution of most of the activities of daily life have been reported., Conclusions: Accordingly with the literature the inverse shoulder megaprosthesis seems able to restore a satisfactory function and the silver-coated modular tumor system appears as a safe and viable treatment option in metastases tumor of proximal humerus.

Purpose: Which total knee arthroplasty (TKA) design represents the better solution to restore a correct knee biomechanics is still debated. The aim of this study was to compare posterior stabilized (PS) and cruciate retaining (CR) version of the same TKA design (femoral component with an anatomic sagittal radius-J-curve design) by the use of dynamic Roentgen stereophotogrammetric analysis (RSA). The hypothesis was that the two models influence differently in vivo knee kinematic., Methods: A cohort of 16 randomly selected patients was evaluated 9 months after surgery: Zimmer PERSONA® was implanted, eight with CR design and eight with PS design. The kinematic evaluations were performed using a Dynamic RSA (BI-STAND DRX 2) developed in our Institute, during the execution of the sit-to-stand motor task. The motion parameters were obtained using the Grood and Suntay decomposition and the low-point kinematics methods., Results: PS TKA lateral femoral compartment had a wider anterior translation (17 ± 2 mm) than the medial one (11 ± 2 mm), while the two compartments of CR TKA showed a similar anterior translation (medial: 9 ± 2 mm/lateral: 11 ± 2 mm). T test for comparison between CR and PS TKA of antero-posterior translation showed a statistically significant difference (p < 0.05) in the flexion range between 15° and 40°. The CR prosthesis did not anteriorly translate during flexion. The PS design translated anteriorly showing a roll-forward mechanism during extension from 80° to 18° of flexion and a posterior translation from 18° to 0°. The same significant differences (p < 0.05) between the PS and CR groups were found comparing the low-point positions of the femoral condyles in the range of flexion between 25° and 40° for the medial compartment and between 15° and 25° for the lateral compartment., Conclusions: Dynamic RSA was able to investigate for the first time in vivo the kinematic behaviour of PS and CR version of the same TKA J-curve design. PS type showed a medial pivot during sit-to-stand motion task, while the CR type showed a cylindrical movement. Further studies are needed to evaluate the impact of different TKA designs on clinical results., Level of Evidence: IV.

Purpose: This work presents a kinematic evaluation of a cruciate retaining highly congruent mobile bearing total knee arthroplasty design using dynamic Roentgen sterephotogrammetric analysis. The aim was to understand the effect of this implant design on the kinematics of prosthetic knees during dynamic activities., Methods: A cohort of 15 patients was evaluated at nine month follow-up after surgery. The mean age was 74.8 (range 66-85) years. The kinematics was evaluated using the Grood and Suntay decomposition and the Low-Point (LP) methods., Results: ?tlsb=-0.15pt?>From sitting to standing up position, the femoral component internally rotated (from -11.3 ± 0.2° to -7.0 ± 0.2°). Varus-valgus rotations were very close to 0° during the whole motor task. LP of medial condyle moved from an anterior position of 12.0 ± 0.2 mm to a posterior position of -12.4 ± 0.2 mm; LP of the lateral condyle moved from an anterior position of 8.1 ± 0.2 mm to a posterior position of -12.4 ± 0.2 mm, showing a bi-condylar rollback where both condyles moved parallel backward. Moreover, the femoral component showed anterior translation with respect to the tibia from 80° to 20° (from -4.9 ± 0.2 mm to 3.3 ± 0.2 mm), then a posterior translation from 20° to full extension was identified (from 3.3 ± 0.2 mm to 0.5 ± 0.2 mm)., Conclusions: Paradoxical anterior femoral translation and absence of medial-pivoting motion were recorded, highlighting the role of the symmetric deep dishes insert as main driver of the kinematic of this TKA design., Competing Interests: Declaration of competing interest The authors declare that they have no competing interests., (Copyright © 2019 Elsevier B.V. All rights reserved.)

Purpose: To assess, using model-based dynamic radiostereometric analysis (RSA), the biomechanical behaviour of a new design posterior-stabilized (PS) fixed-bearing (FB) total knee arthroplasty (TKA) in vivo while patients performing two common motor tasks. The hypothesis was that model-based dynamic RSA is able to detect different behaviour of the implant under weight-bearing and non-weight-bearing conditions., Methods: A cohort of 15 non-consecutive patients was evaluated by dynamic RSA 9 months after TKA implantation. The mean age of patients was 73.4 (65-72) years. The kinematic evaluations were performed using an RSA device (BI-STAND DRX 2) developed in our Institute. The patients were asked to perform two active motor tasks: sit-to-stand in weight-bearing condition; range of motion (ROM) while sitting on the chair. The motion parameters were evaluated using the Grood and Suntay decomposition and the low-point kinematics methods., Results: The dynamic RSA evaluation showed a significant difference (p < 0.05) between the biomechanical behaviour of the prosthesis during the two motor tasks. When subjected to the patient weight (in the sit-to-stand) the low point of the medial compartment had a shorter motion (5.7 ± 0.2 mm) than the lateral (11.0 ± 0.2 mm). This realizes a medial pivot motion as in the normal knee. In the ROM task, where the patient had no weight on the prosthesis, this difference was not present: the medial compartment had a displacement of 12.7 ± 0.2 mm, while the lateral had 17.3 ± 0.2 mm., Conclusions: Model-based RSA proved to be an effective tool for the evaluation of TKA biomechanics. In particular, it was able to determine that the fixed-bearing posterior-stabilized TKA design evaluated in this study showed a medial pivoting movement under weight-bearing conditions that was not present when load was not applied. Under loading conditions what drives the pattern of movement is the prosthetic design itself. By the systematic use of this study protocol future comparisons among different implants could be performed, thus contributing significantly to the improvement of TKA design., Level of Evidence: IV.