Thermal evaluation of the injectable liquid metal bone cement in orthopedic treatment

The thermophysical properties of bone cement are important parameters for its application in the orthopedic treatment. This article focused on the thermal evaluation of the low-melting-point metal(Bi In Sn alloy), which has been proved to be an excellent bone cement. Firstly, the basic thermophysical properties of Bi In Sn alloys with different melting points were measured.Secondly, 15 fresh porcine femurs placed in the saline bath, bone cements with different melting points and amounts were injected into the bone cavities, respectively. Thermocouples were used to measure the temperature changes of the bone-cement interface and peripheral bone tissue. The possibility of thermal necrosis was evaluated. Moreover, a three-dimensional human knee model was built to numerically assess the effects of thermal parameters, such as melting point and latent heat on tissue temperature distribution. All the experimental and numerical results implied the heat distribution in the tissue depended on the thermal performances of liquid metal bone cement(LMBC). For LMBC of the same melting point, with increased amounts, the damage to the bone tissue is more severe, while for the same amount of different melting point LMBCs, with the higher melting point, which will lead to more serious damage to the tissue. Also, higher latent heat of LMBC has distinct longer solidification process, which may cause irreversible damage to surrounding tissues. Therefore, in the future, for different clinical surgery needs, the appropriate liquid metal bone cement can be obtained by adjusting the thermal parameters.

Floating Knee with Vascular Compression Treated Non-Operatively in a Context of Limited Resources: A Case Report

Lower limb fractures like floating knees are more common in urban areas of low-income countries. In addition, associated complex lesions are manifestations of polytrauma requiring correct and appropriate management. The treatment is mostly surgical. We present a 19-year-old patient with a floating knee due to ipsilateral femoral and tibial fractures and vascular compression treated with femoral and calcaneus traction followed by a long limb cast. For our patient, the management of the concomitant vascular compression threatening vital and functional prognosis was in focus aiming at avoiding a radical decision such as limb amputation. The non-operative treatment managed to restore the blood supply and save the limb. At the follow-up after 10 months the fractures were clinically healed and radiologically consolidated and the walking capacity was almost restored. Non-surgical treatment accompanied by daily monitoring can prevent the radical solution of amputation in the context of a floating knee with vascular compression. We want to draw attention to the weakness of the existing classifications because they do not take into account vascular lesions as well as the presence of open fractures to define the severity and evaluate the prognosis.

McBride手术治疗外翻疗效分析

目的总结McBride手术治疗外翻术后5年以上长期随访结果,并分析其疗效。方法自1985年1月～1995年12月,对行McBride矫形术的外翻患者进行随访,共随访50例(90足)。随访时间为5年～10年2个月,平均7年1个月。对畸形矫正程度、局部症状及足趾功能改善情况进行比较和分析,同时在术前、术后对部分患者进行足底负重点变化观察。结果第一跖趾角大小与第一、二跖间角大小有显著的相关性,手术前后相关系数分别为0.84和0.71。两者均与外翻程度有关;手术后足部症状改善、畸形基本矫正者共64足,手术优良率为71.1%。并发症主要有趾及前足疼痛、局部麻木、外翻复发、内翻、仰趾畸形等,部分行再次手术。结论McBride手术能有效地减小已经增大的第一跖趾角;外翻矫正后,第一、二跖间角也会相应缩小。McBride矫形术通过足部软组织力量平衡,能有效地改善患者足部症状、改善足部功能、矫正外翻畸型。对轻、中度及50岁以下较年轻外翻患者是一个较好的、可靠的手术方式。并发症的发生与足部先天性畸形、外翻程度较重及手术中过多的副损伤有关。