Background: As there is a current increasing tendency to treat displaced tibial shaft fractures in adolescents surgically, it has become more important to predict failure of cast treatment for these patients. In the past, redisplacement of pediatric tibial shaft fractures has been reported at rates of 20% to 40%. Although the efficacy of the three-point index (TPI), gap index, and cast index has been demonstrated for upper extremity fractures in children, to date no index has been shown to accurately predict redisplacement for pediatric tibial shaft fractures. The aim of this study was to determine the predictive factors for redisplacement in pediatric tibial shaft fractures. Methods: In all, 157 displaced pediatric tibial shaft fractures were evaluated retrospectively. Patient age, initial and postreduction fracture angulation, shortening and translation, quality of reduction, obliquity of fracture, associated fibular fractures, and 3 indices (TPI, cast index, and gap index) were analyzed. Receiver operating characteristic analysis was performed to determine the cutoff points and logistic regression was used to show the risk factors of redisplacement. Results: There were 53 female and 104 male patients with a mean age of 9.1 (5 to 15 y) and 45 patients developed redisplacement during the follow-up. Mean TPI and gap index and initial and postreduction fracture translation were higher in patients with redisplacement, while TPI>0.855 and postreduction translation >18% were the only independent risk factors for fracture redisplacement. No differences were observed regarding associated fibular fracture, quality of reduction, initial/postreduction angulation, and shortening. Conclusions: The TPI>0.855 and postreduction translation >18% are independent risk factors for redisplacement of tibial shaft fractures in children. Although the gap index can be useful, the cast index is not an appropriate tool for these fractures.

Three-point index (TPI) has been reported to be effective in predicting the displacement of forearm fractures. The aim of this prospective study was to investigate the clinical efficacy of recasting critical but acceptable casts according to three-point index (0.6 < TPI < 0.8) before a redisplacement occurs in childhood forearm fractures. A TPI of 0.6–0.8 was determined in 68 patients, and these were separated as group 1 (n = 34) applied with prophylactic recasting and group 2 (n = 34) where treatment was continued with same cast. The remaining 28 patients had TPI < 0.6 and were assigned as group 3. Groups were compared in respect of age, initial displacement, cast type, location of fracture, initial and late three-point index values and inter- and intraobserver reliabilities of TPI measurements. Significantly less displacement was seen in group 1 than in group 2 (P = 0.004). It was found that a 0.1 increase of index value in the initial and late TPIs increases the probability of redisplacement by 5.06 and 7.78 times, respectively. Late TPI, measured 1 week after casting, had better predictive value than the initial TPI with a sensitivity of 77.8%, specificity of 92.3%, positive predictive value of 70% and negative predictive value of 94.7%. Patients in the grey zone will be able to safely complete the cast treatment with prophylactic recasting without surgical intervention. TPI should be remeasured at the end of first week, as its predictive value becomes more accurate after swelling subsides.

Three-point index (TPI), which can be used in the follow-up of conservative treatment, is an important indicator and reveals objective results about the fracture redisplacement. The hypothesis of the current study was that an initial TPI value of 0.6-0.8 may also be dangerous as it has the potential to exceed over 0.8 before a sufficient consolidation occurs and a prompt revision of the cast may prevent an upcoming displacement. This prospective controlled study 84 patients between 4 and 16 years of age, with radius distal metaphyseal fractures with more than 30% displacement or more than 15° initial angulation, were included. All of the patients in the groups had no redisplacement at 5-7 days and had TPI between 0.6 and 0.8. The patients who had cast replacement and adjusted TPI below 0.6 were included Group 1. The patients who had no cast replacement were included in Group 2. Redisplacement was observed in 8 of 38 (21%) patients in the Group 1 and in 27 of 46 (58%) patients in the Group 2 (P value 0.001). Redisplacement with cast revision was 2.8 times less (P < 0.005). The first reduction quality, fracture obliquity, renewed TPI values were found to be statistically significant for the prediction of redisplacement (P < 0.005). We recommend that the follow-up of the TPI is an important predictive factor in the conservative treatment of pediatric metaphyseal radius fractures. TPI may be renewed for protection of the fracture reduction when calculated in the gray zone which is 0.6-0.08.