Clinical and radiological results of locking plate fixation for periprosthetic femoral fractures around hip arthroplasties: a retrospective multi-center study.

BACKGROUND: Osteosynthesis of periprosthetic femoral fractures around hip arthroplasties is challenging, and locking plate fixation has been found to be a reasonable treatment. However, there is a paucity of evidence of the extent to which patients recover their activities of daily living (ADL). The purpose of this study was to study the clinical results, particularly recovery of ADL, radiological results, and potential complications arising from the use of locking plate fixation for periprosthetic femoral fractures around hip arthroplasties. METHODS: We conducted a retrospective, multi-center study. Patients with periprosthetic femoral fractures around hip arthroplasties who were treated by osteosynthesis with use of locking plates and who underwent follow-up for at least 6 months postoperatively were enrolled in the study. For each patient, recovery of ADL, in terms of social and ambulatory recovery and Parker mobility score, were compared before fracture and at last follow-up. Postoperative complications were investigated. Bony union, loss of reduction, and malunion were assessed radiologically. RESULTS: Thirty-two patients were enrolled in this study. Mean follow-up was 25.1 months. For 84.4, 68.8, and 53.1% of patients, respectively, social status, ambulation, and Parker mobility score at last follow-up were determined to be equal to that before the fracture. Bony union was observed for 30 patients within the follow-up period. Four patients had not achieved bony union 6 months postoperatively. There was no loss of reduction, malunion, or implant breakage, and no infection. For one patient each, partial pullout of the locking screws and a supracondylar fracture at the plate end were observed, and additional surgery was required. CONCLUSIONS: Our results reveal that locking plate fixation provided sufficient stability for satisfactory recovery of ADL for most elderly patients with periprosthetic femoral fractures around hip arthroplasties.

Multicenter study on atypical femoral fractures in patients with bone metastases taking bone- modifying agents.

Bone-modifying agents (BMAs), with bone-resorptive inhibitory effects, such as zoledronic acid and denosumab, are widely used at higher doses for bone-related events caused by bone metastasis of malignant tumors. These drugs have been suggested to be associated with atypical femoral fractures (AFFs), and the relationship between BMAs and AFFs has attracted attention. To investigate the clinical features including bone union time of AFFs in patients administered BMA for bone metastasis, we conducted a retrospective multicenter study. Thirty AFFs from 19 patients were enrolled in this study. Thirteen patients had bilateral AFFs, and nineteen AFFs had prodromal symptoms. Eighteen AFFs underwent surgery after complete fracture, three failed to achieve bone union and required nonunion surgery, and 11 AFFs that achieved bone union had an average period until bone union of 16.2 months, which was much longer than that previously reported for ordinary AFFs. Seven patients discontinued the BMAs, but not due to AFFs. Stopping BMAs in patients with bone metastasis would make it difficult to secure their performance of activities of daily living, and AFF with BMA administration might require a longer time for union. Therefore, it would be important to prevent incomplete AFF from becoming complete AFF via prophylactic internal fixation.

Nongenetic control of receptor signaling dynamics using a DNA-based optochemical tool.

Optochemical tools that can modulate the activity of the target protein provide an opportunity for studying and regulating the related biological processes. Here we present a DNA-based nongenetic optochemical tool that can control the dynamics of growth factor signaling. This photo-caged mimicry of growth factor can be a promising tool for elucidating a linkage between the dynamics of signaling and the resulting biological outcomes, as well as for manipulating cellular functions and the fate of living cells.

Numerical Investigation of the Flow Past a Rotating Golf Ball and Its Comparison with a Rotating Smooth Sphere.

Large-eddy simulations are conducted for a rotating golf ball and a rotating smooth sphere at a constant rotational speed at the subcritical, critical and supercritical Reynolds numbers. A negative lift force is generated in the critical regime for both models, whereas positive lift forces are generated in the subcritical and supercritical regimes. Detailed analysis on the flow separations on different sides of the models reveals the mechanism of the negative Magnus effect. Further investigation of the unsteady aerodynamics reveals the effect of rotating motion on the development of lateral forces and wake flow structures. It is found that the rotating motion helps to stabilize the resultant lateral forces for both models especially in the supercritical regime.

A surgical approach for an avulsion fracture of the ischial tuberosity: a case report.

We report a case of an avulsion fracture of the ischial tuberosity treated with a new surgical approach early after injury. Although surgical treatment of this fracture is usually avoided because of the difficulty of the procedure and the risk of sciatic nerve complication, we believe our subgluteal approach is simple and safe. We therefore recommend it for treating avulsion fractures of the ischial tuberosity, especially when the fragment is displaced by >2 cm and the sciatic nerve is not involved. If there is clinical evidence of sciatic nerve disturbance, it is likewise an indication for surgery. However, the incision needs to be deepened to approach the nerve, along the lines of the incisions advocated by both Miller and Spinner.

Traumatic dislocation of the hamate and pisiform: a case report and review of the literature.

Isolated dislocation of the hamate bone and pisiform bone is rare. We describe the simultaneous complete dislocation of both the hamate and pisiform bones in a 27-year-old man who crushed his right hand in a rolling press. An open reduction and internal fixation with Kirschner wires was performed. Four weeks later, the Kirschner wires were removed and rehabilitation was started. At 6 months follow-up, the patient had minimal pain and full range of motion in the affected wrist joint and fingers. However, grip strength was 50% compared to his unaffected left hand, and sensation of the ulnar nerve area was reduced to almost 30% of that of his left hand. It appears that the ulnar nerve injury was the largest contributing factor to the poor outcome of our patient. Evaluation of soft-tissue injuries, especially nerve injury, is important in the treatment of complex carpal dislocations.

[Treatment of non-union and delayed-union by low intennsity pulsed ultrasound].

Low intensity pulsed ultrasound (LIPUS) has been used for non-union and delayed-union since 1998 in Japan. The LIPUS signal is 200 microsecond sine wave of 1.5 MHz repeating at a frequency of 1 KHz. The intensity is 30 mW/cm(2) spatial and temporal average. Application of LIPUS to healing fractures has been shown to increase the mechanical strength of the callus, including torque and stiffness, and reduce the time to bone union in animal models and clinical trials. The mechanism of LIPUS for acceleration of fracture healing is still unclear, but we speculate that micro mechanical stress transferred by the ultrasound signal stimulates enchondral ossification. Success rates for non-union and delayed-union are 80% in Japan.

[Healing process of fracture].

Fracture healing consists of a sequence of events beginning with inflammation, followed by repair of the damaged tissue and then remodeling of the newly formed tissue, ultimately restoring the injured bone to its original state. Bone induction is also a sequential cascade of cellular and molecular events that includes chemotaxis, mitosis and differentiation. Several signaling molecules, such as inflammatory cytokines, morphogens and growth factors, are produced during fracture healing and initiate the cascade of critical cellular events of fracture healing. If the fracture healing cascade is disturbed, the fracture does not heal normally, resulting in nonunion.

Low-intensity pulsed ultrasound enhances early healing of medial collateral ligament injuries in rats.

OBJECTIVE: To investigate the effect of low-intensity pulsed ultrasound exposure on the healing of injured medial collateral ligaments. METHODS: Thirteen male Sprague Dawley rats were used in the study. After surgical transection of the bilateral medial collateral ligaments, the ligament of 1 knee received low-intensity pulsed ultrasound exposure (30 mW/cm2 for 20 minutes daily), whereas no ultrasound was applied to the contralateral knee (control side). Eight rats were killed at 12 days after surgery, and 5 rats were killed at 21 days. The bilateral knees of 5 rats were used for mechanical testing at each of the 2 periods, and 12-day specimens of the remaining 3 rats were prepared for the electron microscopic examination. The knees of 5 additional rats were used to obtain mechanical data of the normal uninjured medial collateral ligament. RESULTS: On the 12th day, the low-intensity pulsed ultrasound-treated side exhibited significantly superior mechanical properties when compared with the control side in ultimate load, stiffness, and energy absorption (P < .05). However, the treatment did not afford any mechanical advantage when tested on the 21st day. The mean diameter of the fibril was significantly larger on the treatment side than on the control side (P < .05). CONCLUSIONS: Low-intensity pulsed ultrasound exposure is effective for enhancing the early healing of medial collateral ligament injuries.

Ultrasound treatment of nonunion of the hook of the hamate in sports activities.

Two cases of nonunion of the hook of the hamate were treated with low-intensity pulsed ultrasound. The patients were baseball players and had been injured as a result of hitting repeatedly. Nonunion was detected on computed tomography (CT) and was exposed to ultrasound for 20 min a day for 4 months. In both cases pain at the hypothenar eminence disappeared, and bone union was confirmed on CT at the end of the ultrasound treatment.