Prevention and management of external fixator pin track sepsis

Pin track-associated complications are almost universal findings with the use of external fixation. These complications are catastrophic if it leads to the failure of the bone-pin interface and could lead to pin loosening, fracture non-union and chronic osteomyelitis. Strategies proposed for the prevention and management of pin track complications are diverse and constantly changing. Prevention of external fixation pin track infection is a complex and ongoing task that requires attention to detail, meticulous surgical technique and constant vigilance.     

The influence of hydroxyapatite coating of external fixator pins on pin loosening and pin track infection: A systematic review

Objective

The primary objective of this systematic review of published randomised controlled trials was to evaluate whether there was a clinical benefit in terms of pin loosening and pin track infection, or deep infection, associated with hydroxyapatite coating of external fixator pins. The secondary objective was to evaluate whether there was a clinical benefit in terms of loss of alignment or malunion associated with hydroxyapatite coating of external fixator pins.

Methods

Studies included were identified by a PubMed search for relevant randomised controlled trials on the 20th of December 2007. A systematic review was performed.

Results

All of the studies concluded that there was significantly less pin loosening in the HA-coated groups although the definition of loosening was based on different criteria. However, there was insufficient evidence to properly evaluate the clinical benefit in terms of the numbers needed to treat to avoid premature pin removal. There was also insufficient evidence to evaluate whether any clinical benefit is gained by using HA-coated pins with respect to deep infection and malunion.

Conclusion

A well designed large randomised controlled trial is required to determine the numbers needed to treat with HA-coated pins to reduce the incidence of clinically relevant pin loosening, axial deformity and pin track or deep infection.     

螺纹外露对外固定架钉道感染的影响

目的 观察螺纹外露对外固定钉道感染的影响。方法 回顾性分析2003年12月至2017年1月我院骨科收治的332例胫腓骨开放性骨折病人的临床资料,均采用单边外固定架临时固定。其中男220例,女112例;左侧177例,右侧155例;年龄为（33.4±2.6）岁（27~51岁）。按Gustilo分型：Ⅱ型79例,Ⅲ型253例。外固定架固定时间为（76.3±9.2） d（66~93 d）。按螺纹是否外露,分为皮外组与皮内组,其中皮外组164例,皮内组168例。取出Schanz螺钉时,采集钉道浅表和深部的分泌物样本,并送细菌培养。记录钉道愈合情况、浅表和深部细菌培养结果及其类型。结果 皮内组钉道愈合等级（甲级：66例;乙级：99例;丙级：3例）优于皮外组（甲级：50例;乙级：90例;丙级：24例）,差异有统计学意义（χ²=19.456,P=0.001）。皮外组浅表感染96例,皮内组浅表感染101例,差异无统计学意义（χ²=0.086,P=0.769）。皮外组深部感染21例,皮内组2例,两组比较差异有统计学意义（χ²=17.362,P=0.001）。皮外组与皮内组钉道感染均以金黄色葡萄球菌为主要菌种,两组间的细菌构成比比较,差异无统计学意义（Z=-0.135,P＞0.05）。结论 螺纹外露会增加单边外固定深部感染概率,应尽量将螺纹置入皮下或选择短螺纹螺钉。     

Spread of infection, in an animal model, after intramedullary nailing of an infected external fixator pin track.

Implant sepsis. due to previous external fixator pin track infection, is the most common complication of secondary intramedullary (IM) nailing of the tibia. We have developed an animal model, which allows different treatment methods to be studied. Using an established ovine model of a pin track infection, Staphylococcus aureus was used to infect the external fixator pins, two weeks prior to reamed IM nailing. In the control group, the animals were killed at a mean of 10.5 days following nailing, when widespread infection was evident, with septic arthritis, abscess formation, and infection of the entire length of the tibia in all six animals. In the treatment group, before IM nailing, the pin sites were debrided, and both local and systemic antibiotics were administered. All surgical wounds healed without evidence of infection, 4 of the 6 animals survived for 28 days, and bacteria were only isolated from 1 of the 6 implants. Treatment was successful at reducing, but not eliminating, infection after secondary nailing.     

The effect of HIV infection on the incidence and severity of circular external fixator pin track sepsis: a retrospective comparative study of 229 patients

Pin track sepsis is a common complication of circular external fixation. HIV status has been implicated as an independent risk factor for the development of pin track infection and has been cited as a reason not to attempt complex limb reconstruction in HIV-positive patients. This retrospective review of patients treated with circular external fixators looked at the incidence of pin track sepsis in HIV-positive, HIV-negative and patients whose HIV status was unknown. The records of 229 patients, 40 of whom were HIV-positive, were reviewed. The overall incidence of pin track sepsis was 22.7 %. HIV infection did not affect the incidence of pin track sepsis (p = 0.9). The severity of pin track sepsis was not influenced by HIV status (p = 0.9) or CD₄ count (p = 0.2). With the employment of meticulous pin insertion techniques and an effective postoperative pin track care protocol, circular external fixation can be used safely in HIV-positive individuals.     

Does external fixator pin site distance from definitive implant affect infection rate in pilon fractures?

Introduction

Tibial pilon fractures are often treated with initial external fixation followed by delayed definitive fixation. It has been postulated that the external fixator pin site may correlate with infection risk. The purpose of this study was to determine whether external fixator pin-site distance from definitive implants impacts the risk of deep infection in pilon fractures.

Experimental analysis of effects of pin pretensioning on external fixator rigidity

The effects of same-fragment pin pretensioning on the rigidity of a simple fixator system were investigated. An external fixator device constructed to apply same-fragment pin pretensioning of a defined amount was applied to a bone model made of pedilen cylinders. System rigidity was tested for varying degrees of pin pretensioning in axial compression and AP bending. Pin pretensioning, bringing transfixing pins together, tended to weaken the system in both modalities tested. Tensioning by bringing the pins apart increased the rigidity of the system in AP bending and axial compression.     

Experimental analysis of effects of pin pretensioning on external fixator rigidity

Summary The effects of same-fragment pin pretensioning on the rigidity of a simple fixator system were investigated. An external fixator device constructed to apply same-fragment pin pretensioning of a defined amount was applied to a bone model made of pedilen cylinders. System rigidity was tested for varying degrees of pin pretensioning in axial compression and AP bending. Pin pretensioning, bringing transfixing pins together, tended to weaken the system in both modalities tested. Tensioning by bringing the pins apart increased the rigidity of the system in AP bending and axial compression.     

经皮斯氏针撬拨复位外固定架治疗粉碎性跟骨骨折

目的探讨经皮斯氏针撬拨复位外固定架治疗粉碎性跟骨骨折的疗效。方法采用经皮斯氏针撬拨复位外固定架治疗32例（37足）粉碎性跟骨骨折患者。结果骨折均获解剖复位。32例均获随访,时间2～12个月。Btihler角术前为-22°～26°（8、5°±12．3°）,拆除外固定架后为24°～35°（28．4°±6．2°）;Gissane角术前为136°～168°（155．2°±9．4°）,拆除外固定架后为108°～142°（127．6°±17．7°）;差异均有统计学意义（P〈0．05）。根据美国足踝骨科协会（AOFAS）踝-后足评分系统进行评分：优27足,良6足,可4足,优良率为89．20％。无伤口感染,斯氏针及外固定针无断裂、松动、滑脱。3例发生创伤性关节炎,经药物治疗后症状缓解。结论经皮斯氏针撬拨复位外固定架治疗粉碎性跟骨骨折能够达到解剖复位,术后并发症少,疗效确切。     

Ilizarov fixator pin site care: The role of crusts in the prevention of infection

Pin site infection is one of the most common local complications after procedures using the Ilizarov fine wire fixator. In this study, the rate of infection was investigated in two groups of patients, representing two consecutive case series, undergoing fracture stabilisation or lower limb reconstruction using an Ilizarov fine wire fixator. Both groups received identical Russian-style pin site care, except in the first Group A where the crusts of dried exudate were removed at the time of pin site cleaning; while in the subsequent Group B, the adherent crusts were retained during cleaning. Pin site infection was diagnosed if the site was painful and inflamed or discharging. The first infected pin site while the fixator remained in situ was considered the outcome of interest. Group A consisted of 59 patients and Group B of 33 patients. A lower proportion of patients in Group B (12/33 – 36%) developed a pin site infection compared to Group A (36/59 – 61%) (p = 0.023). However, once infection had developed, a greater proportion of patients in Group B required more than one course of antibiotics to treat the infection when compared to patients in Group A (p = 0.005). No patient required hospitalisation for intravenous antibiotics or wire change in Group B (0/33), whereas 3/59 patients required hospitalisation in Group A; but this did not reach statistical significance (Chi-squared test, p = 0.18). Retention of adherent crusts during Ilizarov fixator pin site care significantly protects against the development of pin site infection, but renders subsequently infected pin sites more refractory to treatment. This study therefore suggests that crusts should be retained as long as a pin site remains uninfected. Retained crusts may act as a physical barrier to bacterial contamination (‘biological dressing’).     

外固定支架联合骨片钉在桡骨远端严重粉碎性骨折中的应用

目的研究外固定支架联合骨片钉治疗桡骨远端粉碎性骨折的长期疗效。方法对2010年1月-2011年12月,采用外固定支架联合骨片钉治疗的24例桡骨远端粉碎性骨折患者进行随访研究。按照AO／ASIF分型：C1型7例,c2型6例,C3型11例。随访内容：腕关节活动度（屈曲、背伸、尺偏、桡偏）,前臂旋前、旋后活动范围,握力、捏力及影像学资料（掌倾角、尺偏角、桡骨高度）。按上肢功能评定标准（Disabilities of the Arm、Shoulderand Hand,DASH）和Gartland—Werley腕关节评分标准进行综合评估。结果术后随访12-24个月,平均为15．8个月。X线片示所有骨折均愈合。按Gartland—Wefley腕关节评定,本组优11例,良9例,可4例,优良率为83．3％。结论外固定支架联合骨片钉治疗桡骨远端粉碎性骨折可以达到满意疗效。     

Antimicrobial efficacy of external fixator pins coated with a lipid stabilized hydroxyapatite/chlorhexidine complex to prevent pin tract infection in a goat model.

BACKGROUND: Pin tract infection is a common complication of external fixation. An antiinfective external fixator pin might help to reduce the incidence of pin tract infection and improve pin fixation. METHODS: Stainless steel and titanium external fixator pins, with and without a lipid stabilized hydroxyapatite/chlorhexidine coating, were evaluated in a goat model. Two pins contaminated with an identifiable Staphylococcus aureus strain were inserted into each tibia of 12 goats. The pin sites were examined daily. On day 14, the animals were killed, and the pin tips cultured. Insertion and extraction torques were measured. RESULTS: Infection developed in 100% of uncoated pins, whereas coated pins demonstrated 4.2% infected, 12.5% colonized, and the remainder, 83.3%, had no growth (p < 0.01). Pin coating decreased the percent loss of fixation torque over uncoated pins (p = 0.04). CONCLUSION: These results demonstrate that the lipid stabilized hydroxyapatite/chlorhexidine coating was successful in decreasing infection and improving fixation of external fixator pins.     

针道加压护理在外固定器治疗骨折不愈合中的应用

目的 减轻股骨干骨折不愈合行外固定支架固定术后患者针道并发症症状.方法 将30例股骨干骨折不愈合患者随机分为两组各15例,外固定支架固定术后第2天,对照组行常规针道护理,观察组在此基础上予无菌敷料加压包扎.结果 外固定支架固定期间,观察组针道并发症症状显著轻于对照组(P＜0.01).结论 股骨干骨折不愈合行支架外固定术后患者,实施针道加压包扎护理干预,可有效减轻针道并发症症状.     

Biomechanics of the Ilizarov external fixator.

The Ilizarov external fixator exhibits more isotropic mechanical properties in bending and nonlinear axial stiffness than do unilateral and bilateral external fixators. Each frame element--wire size, tension, and orientation, as well as ring type--contributes to overall frame rigidity and stability. These factors and the specific clinical situation must be considered for the successful application of the Ilizarov fixator.     

外固定架在足下垂治疗中的应用

[目的] 探讨外固定架在足下垂畸形治疗中的作用.[方法] 足下垂患者9例,平均足下垂畸形时间15.5个月,将外固定架螺纹杆连接于胫骨与下垂足之间,对足下垂进行缓慢牵拉,每日螺纹旋转3次.[结果] 所有患者均获得随访,平均随访时间11.2个月(6～19个月);足下垂矫形时间3～6周(平均4.2周),足下垂均矫正到中立位,带架时间7～11周(平均8周),所有患者均未发现有神经、肌腱和血管的损伤;6例胫骨骨折、骨不连患者矫形后经过锻炼踝关节功能恢复良好,活动范围约30°～50°;小腿前外侧和后侧肌群挫灭伤患者经过锻炼,踝关节活动范围约12°.[结论] 通过外固定架的缓慢牵拉,可以有效治疗足下垂畸形.     

Frame external fixator. A rapid and simple method of length fixation of distal radius fractures]

In our clinic we used a frame fixator to immobilize a distal radius fracture in 7 cases. The results obtained with regard to length preservation and fracture apposition suggest that this may be a very useful, quick and easy mode of treatment.