Biomechanical Analysis of Pin Placement for Pediatric Supracondylar Humerus Fractures

Department of Pediatric Orthopaedic Surgery, Rady Children's Hospital San Diego, San Diego, CA, USA.
Journal of pediatric orthopedics (Impact Factor: 1.47). 07/2012; 32(5):445-51. DOI: 10.1097/BPO.0b013e318257d1cd
Source: PubMed


Several studies have examined the biomechanical stability of smooth wire fixation constructs used to stabilize pediatric supracondylar humerus fractures. An analysis of varying pin size, number, and lateral starting points has not been performed previously.
Twenty synthetic humeri were sectioned in the midolecranon fossa to simulate a supracondylar humerus fracture. Specimens were all anatomically reduced and pinned with a lateral-entry configuration. There were 2 main groups based on specific lateral-entry starting point (direct lateral vs. capitellar). Within these groups pin size (1.6 vs. 2.0 mm) and number of pins (2 vs. 3) were varied and the specimens biomechanically tested. Each construct was tested in extension, varus, valgus, internal, and external rotation. Data for fragment stiffness (N/mm or N mm/degree) were analyzed with a multivariate analysis of variance and Bonferroni post hoc analysis (P<0.05).
The capitellar starting point provided for increased stiffness in internal and external rotation compared with a direct lateral starting point (P<0.05). Two 2.0-mm pins were statistically superior to two 1.6-mm pins in internal and external rotation. There was no significant difference found comparing two versus three 1.6-mm pins.
The best torsional resistances were found in the capitellar starting group along with increased pin diameter. The capitellar starting point enables the surgeon to engage sufficient bone of the distal fragment and maximizes pin separation at the fracture site. In our anatomically reduced fracture model, the addition of a third pin provided no biomechanical advantage.
Consider a capitellar starting point for the more distally placed pin in supracondylar humerus fractures, and if the patient's size allows, a larger pin construct will provide improved stiffness with regard to rotational stresses.

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    • "Two wires may be applied in a "V" or "X" configuration in order to increase the stability of the fracture and to decrease the time spent in a cast. Other authors recommend and use fixation with three wires [8-11]. "
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    ABSTRACT: Background. The Study and Research Group in Pediatric Orthopedics-2012 initated this retrospective study due to the fact that in Romania and in other countries, the numerous procedures do not ensure the physicians a definite point of view related to the therapeutic criteria in the treatment of supracondylar fractures. That is why the number of complications and their severity brought into notice these existent deficiencies. In order to correct some of these complications, cubitus varus or valgus, Prof. Al. Pesamosca communicated a paper called "Personal procedure in the treatment of posttraumatic cubitus varus" at the County Conference from Bacău, in June 24, 1978. This procedure has next been made popular by Prof. Gh. Burnei and his coworkers by operating patients with cubitus varus or valgus due to supracondylar humeral fractures and by presenting papers related to the subject at the national and international congresses. The latest paper regarding this problem has been presented at the 29th Annual Meeting of the European Pediatric Orthopedic Society in Zagreb, Croatia, April 7-10, 2010, being titled "Distal humeral Z-osteotomy for posttraumatic cubitus varus or valgus", having as authors Gh. Burnei, Ileana Georgescu, Ştefan Gavriliu, Costel Vlad and Daniela Dan. As members of this group, based on the performed studies, we wish to make popular this type of osteosynthesis, which ensures a tight fixation, avoids complications and allows a rapid postoperative activity. Introduction. The acknowledged treatment for these types of fractures is the orthopedic one and it must be accomplished as soon as possible, in the first 6 hours, by reduction and cast immobilization or by closed or open reduction and fixation, using one of the several methods (Judet, Boehler, Kapandji, San Antonio, San Diego, Burnei's double X technique). The exposed treatment is indicated in irreducible supracondylar humeral fractures, in reducible, but unstable type, in polytraumatized patients with supracondylar fractures, in supracondylar fractures with vascular injury, in late presenting fractures, in case of loss of reduction under cast immobilization or in case of surgery with other types of fixation that is deteriorated. We have been using Burnei's osteosynthesis for about 10 years. Aim. This paper aims to present the operative technique, its results and advantages. Materials and methods. 56 cases were treated with Burnei's "double X" osteosynthesis in "Alexandru Pesamosca" Surgery Clinics, from 2001 to 2011. We used the Kocher approach and the aim of surgery was to obtain a fixation that does not require cast immobilization and that allows motion 24 hours after the surgery. The wires placed in "double X" must not occupy the olecranon fossa. The reduction must be anatomical and the olecranon fossa free. Flexion and extension of the elbow must be in normal range after surgery without crackles or limitations. This surgery was performed on patients with: • Loss of reduction after 10 days with cast immobilization; • Surgery with other types of fixation, deteriorated; • Polytraumatized patients with supracondylar fracture; • After neglected or late presenting fractures, without the orthopedic reduction made in emergency; • Fractures with edema and blistering. Results and complications. The patients' ages ranged 3 to12 years old, the mean age for girls was 7,3 years and 6,8 for boys. The hospitalization ranged 3 to 7 days, the average period being of 5 days. The wires had been pulled out after 21 days. The total recovery of the flexion and extension motion of the elbow was, depending on the age, between 21 and 40 days with an average period of 30 days. There were 5 cases of minor complications: in 3 cases the wires migrated outwards up to the 10th day and in 2 cases the wires were found in the olecranon fossa. The CT exam highlighted the impingement effect and the wire that passed through the olecranon fossa had to be removed between the 7th and the 9th day. No reported cases of cubitus varus or valgus were reported. Conclusion. The Burnei's "double X" osteosynthesis does not require cast immobilization. In oblique fractures, the stability is more difficult to obtain and by using other methods, elbow stiffness or ulnar nerve palsy may appear. The Burnei's "double X" osteosynthesis ensures stability of these types of fractures and avoids complications. This technique allows early motion after surgery and, in case of polytrauma, ensures comfort both to the patient and the physician, allowing repetitive examinations, preferential positions or the nursing of the extensive skin lesions.
    Full-text · Article · Jun 2013 · Journal of medicine and life
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    ABSTRACT: Introduction: The supracondylar fracture of the distal humerus is the most common pediatric fracture around the elbow. The currently accepted techniques of fixation are two lateral parallel wires , crosswiring technique from the lateral side, two divergent wires laterally and two retrograde crossed wires. The retrograde crossed wires provide the best mechanical stability. Many children with this fracture have swelling around the elbow, making difficult the feeling of the anatomic landmarks for percutaneous pinning, increasing the risk of ulnar nerve injury. Objective: To evaluate the correspondence of the internal antecubital fold line with the internal epicondyle in patients with supracondylar fracture and the incidence of iatrogenic ulnar nerve injuries . Methods: We conducted a series of clinical cases. In the first group we included 56 children with supracondylar fracture Gartland type III, from August 2000 to September 2007, who underwent closed reduction and crossed retrograde nail fixation. In the second group we included 241 (481 elbows) outpatients with no anatomic abnormality. We used the extension of antecubital fold line to find the internal epicondyle in both groups. Results: The prolongation of the antecubital fold line intersected the medial epicondyle in all participants of the first group. In 96.3% of the participants in the second group, the extension of antecubital fold line intersected the internal epicondyle. None patient had iatrogenic ulnar nerve injury. Conclusions: The use of the antecubital internal fold line may be useful to identify the internal epicondyle and thus avoid iatrogenic ulnar nerve injury. Salud UIS 2012; 44 (2): 9-14
    Preview · Article · Dec 2012 · Salud UIS
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    ABSTRACT: BACKGROUND: Closed reduction and percutaneous pin fixation is considered standard management for displaced supracondylar fractures of the humerus in children. However, controversy exists regarding whether to use an isolated lateral entry or a crossed medial and lateral pinning technique. QUESTIONS/PURPOSES: We performed a meta-analysis of randomized controlled trials (RCTs) to compare (1) the risk of iatrogenic ulnar nerve injury caused by pin fixation, (2) the quality of fracture reduction in terms of the radiographic outcomes, and (3) function in terms of criteria of Flynn et al. and elbow ROM, and other surgical complications caused by pin fixation. METHODS: We searched PubMed, Embase, the Cochrane Library, and other unpublished studies without language restriction. Seven RCTs involving 521 patients were included. Two authors independently assessed the methodologic quality of the included studies with use of the Detsky score. The median Detsky quality score of the included trials was 15.7 points. Dichotomous variables were presented as risk ratios (RRs) or risk difference with 95% confidence intervals (CIs) and continuous data were measured as mean differences with 95% CI. Statistical heterogeneity between studies was formally tested with standard chi-square test and I(2) statistic. For the primary objective, a funnel plot of the primary end point and Egger's test were performed to detect publication bias. RESULTS: The pooled RR suggested that iatrogenic ulnar nerve injury was higher with the crossed pinning technique than with the lateral entry technique (RR, 0.30; 95% CI, 0.10-0.89). No publication bias was further detected. There were no statistical differences in radiographic outcomes, function, and other surgical complications. No significant heterogeneity was found in these pooled results. CONCLUSIONS: We conclude that the crossed pinning fixation is more at risk for iatrogenic ulnar nerve injury than the lateral pinning technique. Therefore, we recommend the lateral pinning technique for supracondylar fractures of the humerus in children. LEVEL OF EVIDENCE: Level I, therapeutic study. See Guidelines for Authors for a complete description of levels of evidence.
    No preview · Article · May 2013 · Clinical Orthopaedics and Related Research
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