Lateral-Only Kirschner-Wire Fixation of Type-3 Supracondylar Humerus Fractures in Children with a Special Attention...

Lateral-only Kirschner-wire pinning of supracondylar humerus fracture is superior in avoiding surgery-related ulnar nerve injury. Their disadvantageous effects on stability may be a consequence of inappropriate surgical techniques. We analyzed whether the surgeon's preference for lateral-only fixation is associated with his or her orthopedic competence. We also analyzed the surgical technique-related risk factors of redisplacement.

All children, aged <16 years, with a distal humerus fracture in 2000-2009 were preliminary included (N = 861). Altogether, 24 of the 165 type-3 supracondylar fractures were operated by lateral-only pinning. Loss of reduction in the follow-up was the main outcome, while the close characteristics of the surgical technique and treating surgeon's orthopedic competence were the explanatory variables.

Orthopedic surgeons used lateral-only method in 23.5% of the type-3 fractures (N = 16/68), and other surgeons in 8.2% (N = 8/97)(difference = 15.3%, 95% confidence interval = 4.6%-27.6%, p = 0.005). One-third of the lateral-only treated fractures (29.2%, 95% confidence interval = 12.6%-51.1%) redisplaced. Lateral-entry pins that crossed at the level of the fracture were associated with failure (87.5%), while no patient with appropriate pin configuration failed (difference = 87.5%, 95% confidence interval = 52.1%-97.8%). A shorter distance (<5 mm) between the entry points of the pins was associated with redisplacement (80% vs. 15.8%, difference = 64.2%, 95% confidence interval = 16.1%-86.9%). Open reduction (p = 0.07), insufficient (<4 mm) bone contact (p = 0.28), monocortical pins (p = 0.569), low diverging angle (p = 0.13) or parallel pins (p = 1.0), residual coronal displacement (p = 1.0), >5° changed Bauman angle (p = 0.11), rotational displacement (p = 0.25), and the experience or specialty of the surgeon were not associated with redisplacement.

Lateral-only pins resulted in poor stability in one in three of the patients. Appropriate configuration of the pins was associated with good fracture healing, but crossing the pins at the fracture level and introducing them close to each other were associated with redisplacement. Surgeons with more orthopedic competence selected lateral-only fixation more usually.