The contralateral pain-related behavioral and immunohistochemical changes after hemilateral spinal nerve injury in rats were investigated. We evaluated the longitudinal changes in contralateral mechanical allodynia, expression of tumor necrosis factor (TNF)-alpha and glial fibrillary acidic protein (GFAP)-positive satellite cells in the contralateral dorsal root ganglion (DRG), and expression of astrocytes and microglia in the contralateral spinal dorsal horn after hemilateral spinal nerve injury in rats. In previous studies, hemilateral nerve injury has sometimes induced contralateral neuropathic pain. TNF-alpha expression and glial cell reactions in the DRG and spinal cord play an important role in the neuropathic pain state, and TNF-alpha is released from glial cells in the nervous system. Adult male Sprague-Dawley rats were used. The spinal L5 nerve distal to the DRG was crushed once for 3 seconds. At days 2, 7, 14, and 21 after surgery, mechanical allodynia was determined in bilateral hind paws by the von Frey test. Expression of TNF-alpha and GFAP in bilateral L5 DRGs and expression of GFAP and ionized calcium-binding adaptor molecule-1 (Iba-1) in bilateral L5 spinal dorsal horns were studied using immunohistochemistry and immunoblotting. Mechanical withdrawal threshold of the ipsilateral hind paw was significantly decreased for 21 days. Conversely, mechanical withdrawal threshold of the contralateral hind paw was significantly decreased from 5 to 10 g for 7 days, and was <5 g at days 14 and 21. TNF-alpha expression and GFAP-positive satellite cells in the contralateral DRG significantly increased from day 7 to day 21. In the contralateral spinal dorsal horn, GFAP-positive astrocytes significantly increased for 21 days, but Iba-1 was not significant. These results suggest that contralateral mechanical allodynia induced by hemilateral spinal nerve injury is associated with upregulation of satellite cells and TNF-alpha in the contralateral DRG. In addition, our results suggest that spinal astrocytes play an important role in these contralateral changes.

Background: Peri-implant femoral fractures are increasingly prevalent among the elderly, often leading to re-fractures due to osteoporosis and implant stress. Whole span plating (WSP) has been proposed as a surgical approach to mitigate this risk. Methods: A retrospective study was conducted on 10 patients (mean age: 79.5 years) who underwent WSP for peri-implant femoral fractures between April 2020 and March 2023. Fractures were classified using the Vancouver, NPPIF, and Lewis and Rorabeck systems. Surgical indication required meeting at least two of the following criteria: age ≥ 70 years, history of fragility fracture(s), high fall risk, severe osteoporosis, extensive fracture pattern, or no implant loosening. Results: No re-fractures were observed during a mean follow-up period of 14.5 months. Although 90% of patients required red blood cell transfusions (mean volume: 3.8 units), early weight-bearing was achieved in most cases. Four patients had received osteoporosis treatment, highlighting the need for integrated bone health management. Conclusions: WSP appears to be a feasible and safe surgical option for high-risk patients with peri-implant femoral fractures, potentially reducing the incidence of subsequent fractures. Further studies with larger cohorts and longer follow-up are warranted.

BACKGROUND Periprosthetic tibial fractures following total knee arthroplasty (TKA) are increasingly encountered in very elderly patients, where multiple comorbidities and osteoporosis compromise early mobilization and elevate the risk of complications. Maintaining pre-injury activities of daily living (ADL) while ensuring safe surgical management is challenging. We present a case of a 95-year-old woman with a periprosthetic tibial shaft fracture managed with open reduction, additional plate fixation, and Ilizarov external fixation, enabling immediate postoperative weight-bearing. CASE REPORT A 95-year-old woman who sustained a periprosthetic tibial shaft fracture after a fall had been independently ambulatory indoors and used a cane outdoors. On admission, radiographs showed a Felix Type III tibial fracture. Six days after the injury, the fracture was stabilized using Ilizarov external fixator with additional internal fixation using a small locking plate. This combined approach allowed immediate full weight-bearing from the day after surgery. She had no major complications; a minor pin-site infection was managed conservatively. Bone union was confirmed on computed tomography (CT) at 4 months, and the external fixator was removed. At 1 year, radiographs showed good alignment, and she walked independently without a cane. CONCLUSIONS This case demonstrates that combining Ilizarov external fixation with internal plate fixation can enable immediate postoperative weight-bearing and functional recovery, even in very elderly patients with periprosthetic tibial shaft fractures and severe osteoporosis.

Limb-length discrepancy following lower-extremity trauma significantly affects patients' functioning and quality of life and is generally avoided by anatomical reconstruction. When lower-extremity trauma is accompanied by tibial-nerve injury, standard treatment protocols may require modifications. We describe a 38-year-old Japanese man with a Gustilo type IIIB open tibial-shaft fracture and complete tibial-nerve rupture, which we treated with acute shortening and gradual lengthening (ASGL). The tibia was shortened by 40 mm to facilitate the tibial nerve's direct end-to-end neurorrhaphy at a healthy site. Initial stabilization was achieved using an external fixator, followed by staged internal fixation and soft-tissue reconstruction with a free latissimus dorsi flap. Once flap integration was confirmed, gradual lengthening with an Ilizarov external fixator restored the limb length, with no length discrepancy. Two years post-injury, the patient regained protective plantar sensation and full weight-bearing ability. He achieved advanced functional milestones: a single-leg stance and hopping. Electromyography (EMG) confirmed the intrinsic foot-muscle reinnervation, including the abductor hallucis and interosseous muscles. The patient resumed snowboarding. This case demonstrates that ASGL has advantages for skeletal and soft-tissue reconstruction and nerve recovery optimization. Although nerve grafting can restore sensation, motor recovery is often limited. In young patients with a complete tibial nerve rupture, tibial shortening to allow direct primary repair may provide superior functional outcomes in both sensory and motor domains. This appears to be the first documentation by EMG of the functional recovery of intrinsic foot muscles following tibial-nerve repair.