Clinical analysis of re-fracture after bone healing treated with combined surgery for congenital pseudarthrosis of the tibia in children

Xiping LIU; Kun LIU; Guanghui ZHU

ABSTRACT

Objective:

To explore the possible risks of re-fracture after bone healing in children with congenital pseudarthrosis of the tibia, who were treated with combined surgery.

Methods:

56 children (35 males and 21 females, with an average age of 38.0±9.2 months ranging from 18 to 66 months) with re-fracture after bone healing were retrospectively enrolled from January 2007 to August 2016, during which a total of 142 children with CPT underwent combined surgical treatment in the orthopedics department of Hunan Children's Hospital. Complete healing of the tibial pseudarthrosis, trauma after surgery, breakage of fibula, and the distal end of the tibial intramedullary rod located in the tibial medullary cavity or not were hypothesized as 4 risk factors. Univariate logistic regression analysis was conducted to investigate the correlation between these factors and re-fractures after tibial pseudarthrosis healing.

Results:

The average follow-up was 81.7±10.8 months ranging from 60 to 120 months with at least 5 years after bone healing. For complete or partial healing of the tibial pseudarthrosis after surgery, the number of re-fractures was 48 and 8, respectively; For with or without a history of trauma, the number of re-fractures was 50 and 6, respectively; for with an intact or broken fibula after surgery, the number of re-fractures was 7 and 49, respectively; For entry or no entry of the intramedullary rod into the tibial medullary cavity, the number of re-fractures was 44 and 12, respectively. The results of univariate logistic regression analysis showed that partial healing of the tibial pseudarthrosis after surgery [ OR=0.255, 95% CI (0.107, 0.605), P=0.002], history of trauma [ OR=36.458, 95% CI (13.332, 99.701), P<0.001], incomplete fibula [ OR=0.267, 95% CI (0.108, 0.661), P=0.004], and intramedullary rod insertion into the tibial medullary cavity [ OR=2.640, 95% CI (1.224, 5.695), P=0.013] were associated with re-fracture after bone healing. The number and proportion of cases with recurrent fractures occurring ≤1, 1-3, 3-6, ≥6 years after bone healing were 5 cases, 9% (5/56), 14 cases, 25% (14/56), 22 cases, 39% (22/56), 15 cases, and 27% (15/56), respectively, the difference was statistically significant (χ 2=11.569, P=0.009). With the extension of follow-up time, the number of cases of re-fractures after bone healing increases, mostly occurring more than one year after bone healing. There were 44 cases (47%, 44/94) and 12 cases (25%, 12/48) of re fractures after bone healing in 94 cases of distal intramedullary rods in the tibial medullary cavity and 48 cases of cross ankle joint fixation, respectively. The difference in the incidence of re-fractures was statistically significant (χ 2=6.327, P=0.018). The incidence of intramedullary rod displacement in cases where the distal end of the intramedullary rod is located within the tibial medullary cavity was 100%.

Conclusions:

Factors of partial healing of the tibial pseudarthrosis, a history of trauma, incomplete status of the fibula after surgery, and intramedullary rod's entry into the tibia were risk factors for re-fracture after bone healing treated with combined surgery for CPT. After the healing of the tibial pseudarthrosis, it is not advisable to push the tibial intramedullary rod into the tibial medullary cavity, which can cause unstable fixation of the tibial intramedullary rod and result in displacement, and even affect the development of the tibial mechanical axis or the occurrence of re-fractures.