**3. Results**

#### *3.1. Study Selection*

The initial search yielded 4051 records; after removing 1558 duplicates, 2493 articles were screened using the title and/or abstract. Of these, 2424 records were eliminated for being irrelevant to our analysis by screening titles and abstracts. The full texts of the remaining 69 articles were retrieved for further assessment. Finally, 35 studies were included in the systematic review [30–64]. Figure 1 displays a flow diagram that shows the reasons for exclusion at each stage of the selection process.

**Figure 1.** PRISMA flow diagram.

#### *3.2. Study Characteristics*

The main characteristics of the included observational studies are presented in Table 1, and the main characteristics of the included case reports and case series are shown in Supplementary Material Table S2. In total, four case reports [30–33], four case series [34–37], 21 retrospective cohort studies [38–45,47–49,52,53,55–58,60,61,63,64], three retrospective case-control studies [46,51,62], and three prospective cohort studies [50,54,59] were included in this systematic review. These studies were published between 1997 and 2022 [30–64]. Among the included studies, 25 were from Asia [33–36,39,40,42–50,52,54–56,60,61,63,64], six were from Europe [31,32,37,41,51,53], and four from North America [30,38,59,62]. Except for Xu et al. [64], which included patients aged over 65 years, other trials were of adult patients [30–63]. The fracture level, surgical management, fixation methods, time to implant removal, the reason for implant removal, and duration of follow-up were also quite different among the studies. The more-detailed characteristics of the included observational studies are listed in Table 2, and other detailed characteristics of included case reports and case series are summarized in Supplementary Material Table S3.


**Table 1.** Baseline

characteristics

 of the included

observational

 studies.


**Table 1.** *Cont.*


**Table 2.**

Reported clinical outcomes in the

observational

 studies.


**Table**

**2.**

*Cont.*

#### *3.3. Risk of Bias*

The pre-planned risk of bias was not assessed during this systematic review. Due to the present lack of high-quality evidence, case reports and case series studies were predetermined to be included to provide related information on our topic. Even if we also included retrospective cohort studies, retrospective case–control studies, and prospective cohort studies, the quality of the observational studies was not assessed due to the inherent biases associated with these study designs and the lack of a control group in many studies.

In addition, the pre-defined meta-analyses were unfeasible due to insufficient data for these clinical outcomes and considerable clinical heterogeneity and variations in outcome measures.

#### *3.4. Primary Outcomes*
