Novel cross-locking intramedullary nails for olecranon: a finite element analysis and specimen experiments / 中华创伤骨科杂志

Objective:To determine the mechanical properties of our self-designed novel cross-locking intramedullary nails and the impact of number of conical locking nails on the fixation through a finite element analysis and specimen experiments.Methods:Mimics 19.0 and SolidWorks 2014 were used to create transverse fracture models of the olecranon which were subjected to fixation with respectively K-wire tension band (KTB) and our self-designed novel cross-locking intramedullary nails (NIN). The strengths of KTB and NIN fixation were analyzed by Ansys. Fifteen human ulna specimens were used to construct a transverse fracture model of the olecranon; an Instron E10000 mechanical testing machine was used to determine mechanical properties in fixation respectively with KTB, one NIN (NIN-1) and 3 NINs (NIN-3).Results:In the finite element analysis, in simulation of the forearm flexed at 45° under a 100 N load, the deformation of the fracture surface of the olecranon in fixation with KTB, NIN-1 and NIN-3 was respectively 0.131 mm, 0.123 mm and 0.121 mm. In the specimen experiments, in simulation of the forearm flexed at 45°, the maximum failure loads for fixation with KTB, NIN-1 and NIN-3 were (313.38±27.68) N, (528.56±53.58) N and (871.04±94.95) N, respectively, showing significant differences among the 3 groups ( P<0.05). The maximum failure load for NIN-3 fixation was significantly greater than that for KTB or NIN-1 fixation, and the maximum failure load for NIN-1 fixation was significantly greater than that for KTB fixation ( P<0.05). Conclusions:Compared with KTB fixation, NIN fixation is more convenient in operation and has better mechanical properties. NIN-3 fixation has the best mechanical properties.

A precise navigation device for fixation of patella fractures with modified K-wire tension band:a comparative retrospective study.

BACKGROUND: Traditionally, the technique of modified tension band wires (MTBW) has been the most commonly used surgical procedure. The purpose of this study is to design a precise navigation device that can obtain a standard position of K-wires for (MTBW) and to compare the precise MTBW (P-MTBW) by a navigation device with the conventional MTBW (C-MTBW) by hands in a retrospective study. METHODS: The device was designed by solidworks2012 software (USA), which could provide a precise guidance for obtaining parallel K-wires. Besides, it could set the distance between two K-wires and the level of K-wires below patellar anterior surface. From June 2014 to August 2018, a total of 112 patients were employed in this retrospective study. The patients were divided into P-MTBW group and C-MTBW group according to the surgical technique with or without the precise navigation device. We needed to record and analyze the operation time and the number of fluoroscopy, postoperative internal fixation imaging, knee function and complications. RESULTS: There were 54 patients in P-MTBW group and 58 patients in C-MTBW group. There were statistically significant differences (P < 0.001) in the operation time between P-MTBW group (39.5 ± 4.7; range, 32-49 min) and C-MTBW group (53.7 ± 6.8; range, 42-71 min). The number of intraoperative fluoroscopy was significantly less (P < 0.001) in P-MTBW group (4.2 ± 1.4) versus that of C-MTBW group (8.3 ± 2.7). According to Iowa knee score, there was no significant difference (P = 0.268 at 1 year) in function between the two groups. According to our own evaluation criteria for MTBW, anyone in the P-MTBW group was excellent and 26 patients were excellent, 20 patients were good, and 2 patients were fair in the C-MTBW group. CONCLUSION: The navigation device can reduce operation time and intraoperative fluoroscopy frequency. P-MTBW fixation is an accurate and effective surgical procedure for patella fractures.

Efficacy of K-wire tension band fixation compared with other alternatives for patella fractures: a meta-analysis.

BACKGROUND: To compare the efficacy and safety of K-wire tension band fixation (KTB) with other alternative approaches (cannulated screws, cable pin, and ring pin) for treatment of patella fractures by performing a meta-analysis. METHODS: PubMed and EMBASE databases were searched for all relevant studies. Standardized mean difference (SMD) or relative risk (RR) and their corresponding 95% confidence intervals (CIs) were calculated for continuous or dichotomous outcomes via either a fixed- or random-effect model using Stata 13.0 software. RESULTS: Nine literatures involving 949 patients (581 in the KTB group and 368 in the control group) were included. Pooled analysis showed there were no differences in the success rate, operative time, healing time, and number of infections between patients undergoing KTB and others. However, the incidence of complications (RR = 8.04, 95% CI = 4.45-14.53; p < 0.001) and VAS (SMD = 0.642, 95% CI = 0.22-1.06; p = 0.003) were lower, while flexion degree (SMD = - 0.70 95% CI = - 1.04-- 0.36; p < 0.001), Böstman joint function score (SMD = - 0.68, 95% CI = - 1.10-- 0.27; p = 0.001), Iowa knee score (RR = 0.88, 95% CI = 0.81-0.96; p = 0.004), and Lysholm score (SMD = - 0.71, 95% CI = - 1.10-- 0.32; p < 0.001) were significantly higher in patients undergoing alternative approaches than the KTB. Subgroup analysis also demonstrated the cannulated screw fixation was superior to KTB in reducing the incidence of complications. CONCLUSIONS: Alternative treatments may be effective for management of patella fractures and should be attempted to be popularized in clinic.

Cable pin system versus K-wire tension band fixation for patella fractures in Chinese Han population: A meta-analysis.

This meta-analysis compared the therapeutic effect of cable pin system (CPS) with K-wire tension band (KTB) in the treatment of patella fractures among Chinese Han population. The databases of PubMed, Cochrane library, China National Knowledge Infrastructure (CNKI), Chinese WanFang and Chinese VIP were searched for studies on CPS versus KTB in the treatment of patella fractures among Chinese Han population. Literatures were screened according to the inclusion and exclusion criteria. The quality of the studies was assessed, and meta-analysis was performed using the Cochrane Collaboration's REVMAN 5.3 software. A total of 932 patients from 15 studies were included in this meta-analysis (426 fractures treated with CPS and 506 fractures treated with KTB). There were significant differences in duration of hospital stay [mean difference (MD)=-1.07; 95% confidence interval (CI):-1.71 to-0.43], fracture healing time (MD=-1.23; 95% CI:-1.68 to-0.77), flexion degree of knee joint at 6th month after operation (MD=14.82; 95% CI: 10.93 to 18.71), incidence of postoperative complication [risk ratio (RR)=0.16; 95% CI: 0.09 to 0.27] and excellent-good rate of Böstman score (RR=1.09; 95% CI: 1.03 to 1.16) between the CPS group and KTB group, while no significant difference was found in operative time between the two groups (MD=-4.52; 95% CI:-11.70 to 2.67). For the treatment of patella fractures among Chinese Han population, limited evidence suggests that the CPS is more suitable than the KTB when considering the hospital stay, fracture healing time, flexion degree of knee at 6th month after operation, incidence of postoperative complication and excellent-good rate of Böstman joint score. Due to the limitation of high quality evidence and sample size, more large-scale randomized controlled trials are needed to validate the findings in the future.

Cable Pin System versus K-wire Tension Band Fixation for Patella Fractures in Chinese Han Population: A Meta-analysis / 华中科技大学学报（医学）（英德文版）

This meta-analysis compared the therapeutic effect of cable pin system (CPS) with K-wire tension band (KTB) in the treatment of patella fractures among Chinese Han population.The databases of PubMed,Cochrane library,China National Knowledge Infrastructure (CNKI),Chinese WanFang and Chinese VIP were searched for studies on CPS versus KTB in the treatment of patella fractures among Chinese Han population.Literatures were screened according to the inclusion and exclusion criteria.The quality of the studies was assessed,and meta-analysis was performed using the Cochrane Collaboration's REVMAN 5.3 software.A total of 932 patients from 15 studies were included in this meta-analysis (426 fractures treated with CPS and 506 fractures treated with KTB).There were significant differences in duration of hospital stay [mean difference (MD)=-1.07;95％ confidence interval (CI):-1.71 to-0.43],fracture healing time (MD=-l.23;95％ CI:-1.68 to-0.77),flexion degree of knee joint at 6th month after operation (MD=14.82;95％ CI:10.93 to 18.71),incidence of postoperative complication [risk ratio (RR)=0.16;95％ CI:0.09 to 0.27] and excellent-good rate of B(o)stman score (RR=1.09;95％ CI:1.03 to 1.16) between the CPS group and KTB group,while no significant difference was found in operative time between the two groups (MD=-4.52;95％ CI:-11.70 to 2.67).For the treatment of patella tractures among Chinese Han population,limited evidence suggests that the CPS is more suitable than the KTB when considering the hospital stay,fracture healing time,flexion degree of knee at 6th month after operation,incidence of postoperative complication and excellent-good rate of B(o)stman joint score.Due to the limitation of high quality evidence and sample size,more large-scale randomized controlled trials are needed to validate the findings in the future.