A Biomechanical Comparison Of Pin Configurations Used For Percutaneous Pinning Of Distal Tibia Fractures In Children.

BACKGROUND: Percutaneous pin fixation is often used in conjunction with closed-reduction and cast immobilization to treat pediatric distal tibia fractures. The goal of this procedure is to maintain reduction and provide improved stabilization, in effort to facilitate a more anatomic union. We conducted a biomechanical study of the torsional and bending stability of three commonly used pin configurations in distal tibia fracture fixation. METHODS: A transverse fracture was simulated at the metaphyseal/diaphyseal junction in 15 synthetic tibias. Each fracture was reduced and fixed with two Kirschner wires, arranged in one of three pin configurations: parallel, retrograde, medial to lateral pins entering at the medial malleolus distal to the fracture (group A); parallel, antegrade, medial to lateral pins entering at the medial diaphysis proximal to the fracture (group B); or a cross-pin configuration with one retrograde, medial to lateral pin entering the medial malleolus distal to the fracture and the second an antegrade, medial to lateral pin entering at the medial diaphysis proximal to the fracture (group C). Stability of each construct was assessed by resistance to torsion and bending. RESULTS: Resistance to external rotation stress was significantly higher in group A than group B (P = 0.044). Resistance to internal rotation stress was significantly higher in group C than group B (P = 0.003). There was no significant difference in torsional stiffness when comparing group A with group C. Under a medial-directed load, group B and C specimens were significantly stiffer than those in group A (28 N/mm and 24 N/mm vs. 14 N/mm for A; P = 0.001 and P = 0.009, respectively). CONCLUSIONS: None of the three pin configurations produced superior results with respect to all variables studied. Group A configuration provided the highest resistance to external rotation forces, which is the most clinically relevant variable under short-cast immobilization. Parallel, retrograde, medial to lateral pins entering at the medial malleolus provide the greatest resistance to external rotation of the foot while minimizing the potential for iatrogenic injury to soft tissue structures.

Obesity is associated with increased postoperative complications after operative management of distal humerus fractures.

BACKGROUND: Distal humerus fractures commonly require surgical intervention, including open reduction and internal fixation (ORIF) and, more recently in elderly, low-demand individuals, total elbow arthroplasty (TEA). The association of obesity with complications after either of these procedures has not previously been examined. METHODS: A national insurance database was queried for ORIF or TEA for management of a distal humerus fracture using procedural and diagnostic codes. Patients in each operative group were then divided into nonobese and obese cohorts. These cohorts were then queried for postoperative complications within 90 days after the surgical procedure using diagnostic and procedural codes. χ(2) tests were calculated to determine statistical significance, with P < .05 considered significant. RESULTS: A total of 6928 patients who underwent operative management of a distal humerus fracture were identified, including 4215 ORIF and 2713 TEA procedures. The obese ORIF patients had a significantly increased risk of 90-day local (odds ratio [OR], 2.5; P < .0001) and systemic (OR, 5.9; P < .0001) complications. The rates of postoperative infection, venous thromboembolism, and medical complications were significantly higher in the obese ORIF cohort than in nonobese patients. The obese TEA patients had a significantly increased risk of 90-day local (OR, 2.6; P < .0001) and systemic (OR, 4.4; P < .0001) complications. The rates of postoperative infection, venous thromboembolism, and medical complications were higher in the obese TEA cohort than in nonobese patients. CONCLUSIONS: Obesity is associated with significantly higher rates of complications after ORIF and TEA for distal humerus fractures than in nonobese patients.