Loss of pin fixation in displaced supracondylar humeral fractures in children: Causes and prevention
ABSTRACT Although the results are generally good following pin fixation of supracondylar humeral fractures in children, occasionally there is postoperative displacement. The purposes of the present study were to identify the causes leading to loss of fixation after pin fixation and to present methods for prevention.
We evaluated 322 displaced supracondylar humeral fractures that had been treated with percutaneous pin fixation. We examined fracture classification, pin configuration, intraoperative alignment after fixation, change in alignment after fixation, details of additional procedures, and final radiographic and clinical outcomes.
Adequate radiographs were available for 279 of the 322 fractures. Eight (2.9%) of the 279 fractures were associated with postoperative loss of fixation; all eight were Gartland type-III fractures. Seven of these eight fractures initially had been treated with two lateral-entry pins, and one had been treated with two crossed pins. In patients with Gartland type-III fractures, loss of fixation was successfully avoided more often when three pins were used (with fixation being maintained in thirty-seven of thirty-seven patients) as opposed to when two lateral-entry pins were used (with fixation being maintained in thirty-five of forty-two patients) (p = 0.01). In all cases, loss of fixation was due to technical errors that were identifiable on the intraoperative fluoroscopic images and that could have been prevented with proper technique. We identified three types of pin-fixation errors: (1) failure to engage both fragments with two pins or more, (2) failure to achieve bicortical fixation with two pins or more, and (3) failure to achieve adequate pin separation (>2 mm) at the fracture site.
Postoperative displacement following pin fixation of supracondylar humeral fractures in children is uncommon. In the present series, loss of fixation was most likely to occur when Gartland type-III fractures were treated with two lateral-entry pins. There were no failures when three pins were used. In all cases of failure, there were identifiable technical errors in pin placement.
Therapeutic Level III. See Instructions to Authors for a complete description of levels of evidence.
- [Show abstract] [Hide abstract]
ABSTRACT: The most common position of malreduced type III supracondylar humerus (SCH) fractures is internal rotation and medial collapse of the distal fragment. The purpose of this study was to determine the effect of SCH fracture rotational deformity on stability with various pin configurations. Specifically, is the biomechanical stability lost when an SCH fracture is pinned in slight malreduction (compared with anatomical pinning) improved by adding a third pin? Sixty-four synthetic humeri were sectioned in the mid-olecranon fossa to simulate an SCH fracture. Specimens were randomized to an anatomically reduced group or a group with 20 degrees of distal fragment internal rotation (n = 32 per group). Each was randomized to one of 4 pin configurations: 2 laterally divergent pins, 2 crossed pins, 3 laterally divergent pins, or 2 lateral with 1 medial pin (n = 8 per group). All fractures were stabilized with 1.6 mm (0.062 in) Kirschner wires. Models were tested in extension, varus, and valgus for 10 cycles between 5 N and 50 N. Internal and external rotations were tested between +/-1 Nm. Data for fragment stiffness (newtons per millimeter or newton millimeters per degree) were analyzed with a 2-way analysis of variance (p < 0.05). Internally rotated fractures were significantly less stable than the anatomically reduced group for external rotation, internal rotation, and varus loading regardless of pin configuration. Within the malreduced group, 3-pin configurations were more stable than 2-pin configurations in internal rotation, varus, and extension loading. Two lateral divergent pins were similar to 2 crossed pins, except in extension, where 2 lateral pins had greater stiffness. Construct stiffness for malreduced specimens after pinning was less than those pinned with an anatomical reduction when loaded in varus, internal rotation, and external rotation. For simulated fractures with residual internal rotation, the addition of a third Kirschner wire compared with an anatomically reduced 2-crossed-pin configuration resulted in increased stiffness of the model for all loading directions. Consider a 3-pin pattern, either 3 laterally divergent pins or 2 lateral pins and 1 medial pin, for SCH fractures when a less than complete anatomical reduction is obtained.Journal of pediatric orthopedics 01/2008; 28(7):766-72. DOI:10.1097/BPO.0b013e318186bdcd · 1.43 Impact Factor
- [Show abstract] [Hide abstract]
ABSTRACT: Le fratture sovracondiloidee di omero sono le più comuni lesioni del gomito in età pediatrica. Le fratture di tipo I secondo Garland sono trattate incruentemente, mentre quelle di tipo II e III richiedono trattamento chirurgico. Le fratture di tipo II sono trattate con riduzione a cielo chiuso e fissazione. Le fratture tipo III possono richiedere la riduzione a cielo aperto. Dal 2001 al 2011 abbiamo trattato chirurgicamente 44 pazienti, 8 con fratture tipo II e 35 con fratture tipo III. Tutti i pazienti sono stati stabilizzati con 2 fili di Kirschner. Le fratture di tipo II sono state ridotte a cielo chiuso, quelle di tipo III a cielo aperto. Sono stati riscontrati: un caso di disturbi a carico del nervo ulnare e un caso a carico del nervo radiale, regrediti spontaneamente, un caso di lieve deformità in varo e uno in valgo. In nessuna evenienza è stato necessario un nuovo intervento chirurgico.06/2012; 18(1). DOI:10.1007/s10351-012-0005-1
Article: What's New in Pediatric OrthopaedicsThe Journal of Bone and Joint Surgery 07/2006; 88(6):1412-21. DOI:10.2106/JBJS.F.00442 · 4.31 Impact Factor