Frommer Adrien, Roedl Robert, Gosheger Georg, Niemann Maike, Turkowski Dominik, Toporowski Gregor, Theil Christoph, Laufer Andrea, Vogt Bjoern
Pediatric Orthopaedics, Deformity Reconstruction and Foot Surgery, University Hospital Muenster, Muenster, Germany.
General Orthopaedics and Tumor Orthopaedics, University Hospital Muenster, Muenster, Germany.
Clin Orthop Relat Res. 2022 Apr 1;480(4):790-803. doi: 10.1097/CORR.0000000000002036.
Limb lengthening with magnetically driven intramedullary lengthening nails is a fast-developing field and represents an alternative to external fixators. Although previous studies have assessed the application of magnetically driven intramedullary lengthening nails, these studies have been heterogenous regarding the nailing approach, the bone treated, and the implant type; they also have analyzed relatively small patient groups at short follow-up durations.
QUESTIONS/PURPOSES: (1) Is femoral lengthening with magnetically driven antegrade intramedullary lengthening nails accurate and precise? (2) What are the most common complications of treatment? (3) What factors are associated with unplanned additional surgery?
We retrospectively analyzed the longitudinally maintained database of our orthopaedic teaching hospital to identify all patients who underwent surgery for leg length discrepancy (LLD) between October 2014 and April 2019. In total, we surgically treated 323 patients for LLD of 2 cm or more. Of those 55% (177 of 323) were treated with distraction osteogenesis with magnetically driven intramedullary lengthening nails, 18% (59 of 323) with external fixation, and 27% (87 of 323) with epiphysiodesis around the knee. Based on that, 29% (93 of 323) of patients underwent unilateral femoral distraction osteogenesis with magnetically driven antegrade femoral lengthening nails and were eligible for analysis. No patient was excluded, and 3% (3 of 93) were lost before the minimum study follow-up of 2 years, leaving 97% (90 of 93) for analysis. Patients with a distal femoral deformity were treated via a retrograde femoral approach (10% [33 of 323]) or with external fixators (3% [10 of 323]) and were not included in this study. Distraction osteogenesis with magnetically driven intramedullary lengthening nails was not considered for patients with deep tissue infection, those with bone dimensions considered to be too small in relation to the available implants, and for patients younger than 8 years. This study included 90 patients (44 females, 43 left femora) treated for a median (interquartile range) preoperative LLD of 39 mm (32 to 52) at a median age of 15 years (14 to 17). The same limb lengthening system was applied in all patients. The median (IQR) follow-up was 35 months (24 to 78). Data were acquired through a chart review performed by someone not involved in the surgical care of the included patients. Data acquisition was supervised and curated by two of the involved surgeons. Accuracy was calculated as 100 - [(achieved distraction in mm - planned distraction in mm) / (planned distraction in mm) x 100] and precision as 100 - (relative standard deviation of accuracy). Treatment-associated complications were summarized descriptively and characterized as complications resulting in unplanned additional surgery or those not resulting in unplanned surgery. To analyze the risk of unplanned additional surgery by entity, we calculated odds ratios (ORs) comparing the incidence of unplanned additional surgery in the different entity cohorts with the idiopathic LLD cohort as a reference. By calculating ORs, we analyzed the risk for unplanned additional surgery depending on sex, age, surgery time, and previous lengthening. Due to the lack of long-term evidence about motorized lengthening nails remaining in situ and concerns about potential implant-related adverse effects, removal was routinely scheduled 1 year after consolidation. For implant removal, 92% (83 of 90) of patients underwent planned additional surgery, which was not recorded as an adverse event of the treatment. Ninety-seven percent (87 of 90) of patients completed lengthening with the implant remaining in situ until the end of distraction. The median (IQR) distraction length was 37 mm (30 to 45) with a median distraction index of 0.9 mm/day (0.7 to 1.0) and median consolidation index of 31 days/cm (25 to 42).
The calculated accuracy and precision were 94% and 90%, respectively. In total, 76% (68 of 90) of our patients experienced complications, which resulted in 20% (18 of 90) of patients undergoing unplanned additional surgery. The most common complication overall was adjustment of the distraction rate in 27% (24 of 90) of patients (faster: 16% [14 of 90]; slower: 11% [10 of 90]) and temporary restriction of knee motion, which occurred in 20% (18 of 90) of our patients and resolved in all patients who experienced it. The most serious complications were bacterial osteomyelitis and knee subluxation, which occurred in 3% (3 of 90) and 1% (1 of 90) of our patients, respectively. With the numbers available, we found only one factor associated with an increased likelihood of unplanned additional surgery: Patients with postinfectious LLD had higher odds of unplanned additional surgery than patients with idiopathic LLD (7% [1 of 15] versus 50% [3 of 6], OR 14.0 [95% CI 1.06 to 185.49]; p = 0.02). However, we caution readers this finding is fragile, and the confidence interval suggests that the effect size estimate is likely to be imprecise.
Femoral distraction osteogenesis with magnetically driven antegrade intramedullary lengthening nails appears to be an accurate and reliable treatment for femoral lengthening. However, depending on the etiology, a high risk of unplanned additional surgery should be anticipated, and a high proportion of patients will experience temporary joint stiffness. We recommend close orthopaedic follow-up and physiotherapy during treatment. This treatment of LLD can be considered alongside other nails, external fixators, and epiphysiodesis. Multicenter studies comparing this with other approaches are needed.
Level IV, therapeutic study.
使用磁驱动髓内延长钉进行肢体延长是一个快速发展的领域，是外固定器的一种替代方法。尽管先前的研究评估了磁驱动髓内延长钉的应用，但这些研究在钉入方法、治疗的骨骼和植入物类型方面存在异质性；它们还分析了随访时间较短的相对较小的患者群体。
问题/目的：（1）使用磁驱动顺行髓内延长钉进行股骨延长是否准确和精确？（2）治疗最常见的并发症是什么？（3）哪些因素与计划外的额外手术相关？
我们回顾性分析了我们骨科教学医院纵向维护的数据库，以确定2014年10月至2019年4月期间所有因腿长差异（LLD）接受手术的患者。我们总共手术治疗了323例LLD为2 cm或更大的患者。其中55%（323例中的177例）采用磁驱动髓内延长钉进行牵张成骨治疗，18%（323例中的59例）采用外固定治疗，27%（323例中的87例）采用膝关节周围骨骺阻滞术治疗。在此基础上，29%（323例中的93例）患者采用磁驱动顺行股骨延长钉进行单侧股骨牵张成骨，符合分析条件。没有患者被排除，3%（93例中的3例）在至少2年的研究随访前失访，剩下97%（93例中的90例）进行分析。股骨远端畸形患者通过逆行股骨入路（10%[323例中的33例]）或外固定器（3%[323例中的10例]）治疗，未纳入本研究。对于深部组织感染患者、骨尺寸相对于可用植入物过小的患者以及8岁以下患者，不考虑使用磁驱动髓内延长钉进行牵张成骨。本研究包括90例患者（44名女性，43例左侧股骨），术前LLD中位数（四分位间距）为39 mm（32至52），中位年龄为15岁（14至17岁）。所有患者均采用相同的肢体延长系统。中位（IQR）随访时间为35个月（24至78个月）。数据通过由未参与所纳入患者手术护理的人员进行的病历审查获得。数据采集由两名参与手术的外科医生监督和整理。准确性计算为100 - [（实际牵张长度（mm） - 计划牵张长度（mm））/（计划牵张长度（mm））×100]，精确性计算为100 - （准确性的相对标准差）。治疗相关并发症进行描述性总结，并分为导致计划外额外手术的并发症和未导致计划外手术的并发症。为了按实体分析计划外额外手术的风险，我们计算了比值比（OR），将不同实体队列中计划外额外手术的发生率与特发性LLD队列作为参考进行比较。通过计算OR，我们分析了根据性别、年龄、手术时间和先前延长情况计划外额外手术的风险。由于缺乏关于电动延长钉原位留存的长期证据以及对潜在植入物相关不良反应的担忧，通常在骨愈合后1年安排取出。对于植入物取出，92%（90例中的83例）患者接受了计划外的额外手术，这未被记录为治疗的不良事件。97%（90例中的87例）患者在植入物原位留存的情况下完成延长直至牵张结束。中位（IQR）牵张长度为37 mm（30至45），中位牵张指数为0.9 mm/天（0.7至1.0），中位愈合指数为31天/cm（25至42）。
计算出的准确性和精确性分别为94%和90%。我们总共76%（90例中的68例）的患者出现并发症，导致20%（90例中的18例）的患者接受了计划外的额外手术。总体上最常见的并发症是27%（90例中的24例）患者的牵张速率调整（加快：16%[90例中的14例]；减慢：11%[90例中的10例]）以及20%（90例中的18例）患者出现的膝关节活动暂时受限，所有出现该情况的患者均已恢复。最严重的并发症是细菌性骨髓炎和膝关节半脱位，分别发生在3%（90例中的3例）和1%（90例中的1例）的患者中。就现有数据而言，我们仅发现一个与计划外额外手术可能性增加相关的因素：感染后LLD患者计划外额外手术的几率高于特发性LLD患者（7%[15例中的1例]对50%[6例中的3例]，OR 14.0[95%CI 1.06至185.49]；p = 0.02）。然而，我们提醒读者，这一发现并不稳健，置信区间表明效应大小估计可能不准确。
使用磁驱动顺行髓内延长钉进行股骨牵张成骨似乎是一种准确可靠的股骨延长治疗方法。然而，根据病因，应预期有较高的计划外额外手术风险，并且很大一部分患者会出现暂时的关节僵硬。我们建议在治疗期间进行密切的骨科随访和物理治疗。这种治疗LLD的方法可与其他钉、外固定器和骨骺阻滞术一起考虑。需要进行多中心研究将其与其他方法进行比较。
IV级，治疗性研究。
