Background: Newer generation intramedullary (IM) tibial nails provide several distal interlocking screw options. The objectives were to determine: 1) if the new oblique interlocking option provides superior stability,...Background: Newer generation intramedullary (IM) tibial nails provide several distal interlocking screw options. The objectives were to determine: 1) if the new oblique interlocking option provides superior stability, 2) which screw orientation/ configuration is the most biomechanically stable, and 3) if three distal interlocking screws provide better stability. Methods: A preliminary experiment was performed in torsion, compression, and bending tests with four different screw configurations: (I) one medial-to-lateral and one oblique, (II) two me-dial-to-lateral, (III) one medial-to-lateral and one anterior-to-posterior, and (IV) one medial-to-lateral, one anterior-to-posterior and one oblique in simu-lated distal metaphyseal fracture tibiae. Twenty- four Synthes EXPERT tibial IM nails were used for six specimens of each screw configuration. Parts I and II, tibial IM nails were locked with 5.0 mm in-terlocking screws into simulated distal tibiae (PVC and composite analogue tibia). Part III, the two most stable configurations were tested using five pairs of simulated cadaveric distal tibiae metaphy-seal fractures. Results: Significant differences were attributable to distal screw orientation for intrame- dullary nailing of distal tibia fractures. Configura-tions II and IV were found to be more stable than the other two configurations. No significant differ-ence was detected in construct stability in all modes of testing between Configurations II and IV. Dis-cussion: Configuration I did not provide superior stability for the distal tibia fracture fixation. Con-figurations II and IV provided equivalent stability. When choosing IM fixation for treatment of distal tibia metaphyseal fractures two medial-to-lateral screws provide the necessary stability for satisfac-tory fixation. Clinical Relevance: This study indi-cated an option for operative treatment of distal metaphyseal tibia fracture fixation where preserva-tion of soft tissue and rigid stabilization are needed.展开更多
Background: Stress fractures are fatigue-induced, very small cracks in the bone caused by repetitive application of force and most often seen in the weight-bearing bones of the lower extremities of athletes or militar...Background: Stress fractures are fatigue-induced, very small cracks in the bone caused by repetitive application of force and most often seen in the weight-bearing bones of the lower extremities of athletes or military recruits. Case Report: A 47-year-old postmenopausal and heavy smoker woman complained of localized sensitivity on the distal-anterior and medial surfaces of both tibiae, which had been ongoing for 1 month. She moved to a flat at 5th-floor without an elevator a year ago. Bilateral stress fractures were diagnosed by radiographs and confirmed by Magnetic Resonance Imaging (MRI). She was suggested to restrict activities and to use crutches until the symptoms subsided. Bilateral ankle joint pneumatic brace with full heel support was applied. The patient was followed one year after diagnosis. At the 2-month follow-up examination, the patient was pain free and planning to move to a new house. Conclusions: Several risk factors have been defined in the pathogenesis of stress fracture. In the present case, the acute phase had passed and diagnosis could be made from the direct radiographs. Although extremely rarely seen, tibia distal stress fracture should be kept in mind in the differential diagnosis of patients with the relevant risk factors who present with tibia distal localized pain.展开更多
文摘Background: Newer generation intramedullary (IM) tibial nails provide several distal interlocking screw options. The objectives were to determine: 1) if the new oblique interlocking option provides superior stability, 2) which screw orientation/ configuration is the most biomechanically stable, and 3) if three distal interlocking screws provide better stability. Methods: A preliminary experiment was performed in torsion, compression, and bending tests with four different screw configurations: (I) one medial-to-lateral and one oblique, (II) two me-dial-to-lateral, (III) one medial-to-lateral and one anterior-to-posterior, and (IV) one medial-to-lateral, one anterior-to-posterior and one oblique in simu-lated distal metaphyseal fracture tibiae. Twenty- four Synthes EXPERT tibial IM nails were used for six specimens of each screw configuration. Parts I and II, tibial IM nails were locked with 5.0 mm in-terlocking screws into simulated distal tibiae (PVC and composite analogue tibia). Part III, the two most stable configurations were tested using five pairs of simulated cadaveric distal tibiae metaphy-seal fractures. Results: Significant differences were attributable to distal screw orientation for intrame- dullary nailing of distal tibia fractures. Configura-tions II and IV were found to be more stable than the other two configurations. No significant differ-ence was detected in construct stability in all modes of testing between Configurations II and IV. Dis-cussion: Configuration I did not provide superior stability for the distal tibia fracture fixation. Con-figurations II and IV provided equivalent stability. When choosing IM fixation for treatment of distal tibia metaphyseal fractures two medial-to-lateral screws provide the necessary stability for satisfac-tory fixation. Clinical Relevance: This study indi-cated an option for operative treatment of distal metaphyseal tibia fracture fixation where preserva-tion of soft tissue and rigid stabilization are needed.
文摘Background: Stress fractures are fatigue-induced, very small cracks in the bone caused by repetitive application of force and most often seen in the weight-bearing bones of the lower extremities of athletes or military recruits. Case Report: A 47-year-old postmenopausal and heavy smoker woman complained of localized sensitivity on the distal-anterior and medial surfaces of both tibiae, which had been ongoing for 1 month. She moved to a flat at 5th-floor without an elevator a year ago. Bilateral stress fractures were diagnosed by radiographs and confirmed by Magnetic Resonance Imaging (MRI). She was suggested to restrict activities and to use crutches until the symptoms subsided. Bilateral ankle joint pneumatic brace with full heel support was applied. The patient was followed one year after diagnosis. At the 2-month follow-up examination, the patient was pain free and planning to move to a new house. Conclusions: Several risk factors have been defined in the pathogenesis of stress fracture. In the present case, the acute phase had passed and diagnosis could be made from the direct radiographs. Although extremely rarely seen, tibia distal stress fracture should be kept in mind in the differential diagnosis of patients with the relevant risk factors who present with tibia distal localized pain.
