Content of this journal is licensed under a Abstract
Objective:
The optimal timing of pin removal following closed reduction and percutaneous pinning (CRPP) for pediatric Gartland type 3 supracondylar humerus fractures remains controversial. Although pins are commonly removed between the third and fifth postoperative weeks, high-level evidence comparing clinical and radiological outcomes between these time points is limited. This study aimed to evaluate whether pin removal at the third vs. the fifth postoperative week influences radiographic healing or functional outcomes.
Methods:
This retrospective observational study included 95 pediatric patients (aged 3-10 years) with Gartland type 3 supracondylar humerus fractures treated with CRPP between 2020 and 2025. Patients were divided into 2 groups based on the timing of pin removal: the third week (n = 42) and the fifth week (n = 53). Clinical outcomes included elbow range of motion (ROM), carrying angle difference, and the Flynn criteria at 3 and 6 months. Radiological outcomes included Baumann angle, anterior humeral line alignment, and the Radiographic Union Score for Tibia scores. Multivariable linear regression was performed to control for potential confounders. Interobserver reliability was assessed using intraclass correlation coefficients.
Results:
At 3 months, flexion and extension loss were modestly lower in the third-week group (P = .011, r = 0.26 and P = .031, r = 0.22, respectively). However, no significant differences were observed between groups at 6 months in terms of flexion loss, extension loss, total motion loss, carrying angle difference, or Flynn scores (all P > .05). Radiographic Union Score for Tibia scores at the time of pin removal were higher in the fifth-week group (P < .001), reflecting later radiographic assessment; however, no differences were observed at subsequent follow-ups. No cases of loss of reduction, angular deformity, or reoperation occurred in either group. Multivariable analysis demonstrated that pin removal timing was associated with early but not late motion loss.
Conclusion:
Pin removal at the third postoperative week did not compromise final radiological outcomes. In contrast, removal at the fifth week did not confer superior long-term functional recovery. Within the commonly practiced third-to-fifth-week interval, timing of pin removal does not appear to influence final clinical outcomes in pediatric Gartland type 3 supracondylar humerus fractures.
Level of Evidence:
Level III, Therapeutic Study.
Keywords: Elbow range of motion, Gartland classification, Percutaneous pinning, Pin removal timing, Supracondylar humerus fracture
Highlights
Pin removal at 3 vs. 5 weeks did not affect final radiological or functional outcomes in Gartland type 3 fractures.
Early pin removal was associated with modestly better elbow range of motion at 3 months, but this difference resolved by 6 months.
Both pin removal strategies resulted in comparable alignment and final Flynn outcomes.
Introduction
Supracondylar humerus fractures are the most common elbow fractures in the pediatric population and constitute a substantial proportion of upper extremity fractures in children.1 In clinical practice, the most widely used classification system for evaluation and treatment planning is the Gartland classification, which categorizes fractures according to the degree of displacement into types 1, 2, and 3. Gartland type 3 fractures represent completely displaced and unstable injuries and are associated with a higher risk of neurovascular complications, malalignment, and long-term functional sequelae.2,3 For displaced supracondylar humerus fractures, surgical treatment is widely accepted, and closed reduction and percutaneous pinning (CRPP) is commonly used as the primary approach; however, open reduction may be required depending on fracture characteristics and clinical conditions.4-6
Although there is consensus on treatment indications and surgical management, the literature offers no clear agreement on postoperative follow-up protocols, particularly regarding the optimal timing of pin removal. Early pin removal may facilitate earlier mobilization and a quicker return to daily activities.7 In contrast, delayed pin removal may allow additional time for fracture healing, potentially resulting in more advanced radiographic consolidation at the time of pin removal. In the literature on pediatric supracondylar humerus fractures, pin removal is most commonly performed between 3 and 5 weeks postoperatively, with a range of time points reported across studies.8-10 However, no clear consensus exists regarding the optimal timing, and comparative studies remain limited.
The present study aimed to evaluate the effect of pin removal timing on clinical outcomes by examining only Gartland type 3 supracondylar humerus fractures, thereby ensuring a homogeneous study population. Cases managed by surgeons who preferred pin removal at the third postoperative week were compared with those managed by surgeons who preferred removal at the fifth postoperative week. To the best of current knowledge, studies directly comparing different pin removal timings in surgically treated patients with the same fracture type and focusing specifically on clinical outcomes are scarce in the literature. In this context, the study aims to be one of the pioneering investigations assessing the impact of pin removal timing on clinical outcomes within a homogeneous cohort.
It was hypothesized that the timing of pin removal would not result in a statistically significant difference in final clinical outcomes.
Material and methods
Study design and patient selection
Ethical approval was obtained from the institutional ethics committe of Health Sciences University Bursa Yüksek İhtisas Training and Research Hospital (Approval no: 2024-TBEK 2026/02-16, Date: 12.02.2026). It was conducted in accordance with the principles of the Declaration of Helsinki. It was designed as a retrospective, observational study evaluating pediatric patients who underwent surgical treatment for supracondylar humerus fractures between June 2020 and June 2025. Patients were identified through the hospital information management system using the ICD-10 code S42.4. Written informed consent for surgical treatment had been routinely obtained from all patients prior to surgery.
A total of 653 patients younger than 10 years with the ICD-10 code S42.4 were identified between June 2020 and June 2025. Patients with distal humerus fractures other than supracondylar fractures (e.g., medial or lateral condyle fractures) were excluded (n = 127). Additionally, patients with Gartland type 1-2 supracondylar fractures were excluded (n = 340). Further exclusions included patients who underwent open surgery, those with early pin loosening or accompanying neurovascular complications, as well as cases with incomplete radiographs or loss to follow-up (n = 91). Patients with early pin loosening were excluded as this represents an early mechanical complication that could independently influence outcomes and confound the evaluation of pin removal timing. The remaining 95 patients constituted the final study cohort and were divided into 2 groups according to pin removal timing: approximately 3 weeks (n = 42) and approximately 5 weeks (n = 53). Only patients treated with CRPP were included in the final analysis. The patient selection process is summarized in the flow diagram (Figure 1).
Figure 1.
Data selection flow chart diagram.
Surgical technique and postoperative follow-up
All patients underwent CRPP under general anesthesia. All procedures were performed by senior orthopedic and traumatology surgeons experienced in pediatric trauma. Pediatric trauma cases were managed within a shared institutional trauma service. Postoperative pin removal timing followed the surgeons’ routine outpatient follow-up practices, while perioperative management and rehabilitation protocols remained standardized across the service. The number of pins and pin configuration (lateral-only pinning or crossed pinning) were determined based on intraoperative stability and surgeon preference. Routine intraoperative fluoroscopic dynamic assessment was performed following K-wire fixation. Postoperatively, all patients were immobilized with a long-arm splint. Regardless of group allocation, splint immobilization was discontinued at the end of the third postoperative week in all patients. Following splint removal, a gentle early rehabilitation program was initiated in all cases.
Grouping
Patients were divided into 2 groups according to the timing of pin removal. Early pin removal group: patients whose pins were removed at approximately the third postoperative week (n = 42); Late pin removal group: patients whose pins were removed at approximately the fifth postoperative week (n = 53). No additional interventions beyond standard clinical follow-up were performed within the scope of the study. The timing of pin removal was determined according to each surgeon’s routine clinical practice, and no study-related protocol influenced this decision.
Clinical evaluation
Clinical assessments were performed in the pediatric orthopedic outpatient clinic. Elbow range of motion (ROM) and carrying angle measurements constituted the primary clinical parameters. Flexion and extension were measured, and flexion loss and extension loss were recorded separately using the contralateral, uninjured side as the reference. Carrying angle measurements were performed in accordance with standard methods described in the literature, comparing both upper extremities.11 Clinical evaluations were conducted at the third and sixth postoperative months. Final clinical outcomes were assessed using the Flynn criteria, which are based on elbow ROM loss and change in carrying angle.12 To enhance measurement reliability, 2 experienced orthopedic surgeons independently performed all clinical assessments in the presence of a physiotherapist, and the measurements were recorded separately. The method of clinical angle measurement is illustrated in Figure 2.
Figure 2.
Clinical measurement of elbow alignment and range of motion. (A) Carrying angle is measured by a manual goniometer with 2 drawing axes of the arm and forearm. The axis of the arm is defined by the anterolateral surface of the acromion to the midpoint of the lateral and medial epicondyles of the humerus. The axis of the forearm is defined by the midpoint of the lateral and medial epicondyles of the humerus to the midpoint of the distal radial and ulnar styloid processes. (B) Measurement of extension deficit. The elbow was brought to the maximum possible extension, and the goniometer was aligned with the longitudinal axes of the humerus and forearm. Any residual angle preventing full extension was recorded as the extension deficit in degrees. (C) Measurement of elbow flexion angle. The elbow was actively flexed, and the goniometer was aligned along the longitudinal axes of the humerus and forearm to measure the maximum flexion angle.
Radiological evaluation
Radiological assessment was performed using standard anteroposterior and lateral elbow radiographs. To ensure measurement accuracy, all evaluations were conducted on digital imaging and communications in medicine images obtained through the hospital’s picture archiving and communication system. Reduction quality was assessed using the Baumann angle on anteroposterior radiographs and anterior humeral line (AHL) alignment on lateral radiographs. Anterior humeral line alignment was categorized according to whether the line passed through the anterior, middle, or posterior third of the capitellum, as previously described in the literature.13
Fracture union was evaluated radiographically at the time of pin removal and at the third and sixth postoperative month follow-up visits. Radiographic union was assessed using the Radiographic Union Score for Tibia (RUST) adapted for pediatric supracondylar humerus fractures. In this system, cortical callus formation and fracture line continuity were evaluated separately for each cortex on anteroposterior and lateral radiographs, and the total score was calculated to reflect the degree of union. This method was applied in accordance with RUST-based evaluation systems described in the literature for pediatric supracondylar fractures.14 All radiological measurements were independently performed and recorded by 2 experienced orthopedic surgeons. Representative preoperative, postoperative, and post–pin removal radiographs, along with examples of the measurements, are presented in Figure 3.
Figure 3.
Radiographic evaluation of supracondylar humerus fracture. (A, B) Preoperative radiographs. Anteroposterior and lateral elbow radiographs showing a displaced supracondylar humerus fracture. (C, D) Postoperative radiographs. Immediate postoperative anteroposterior and lateral radiographs demonstrating fracture reduction and fixation with percutaneous Kirschner wires. (E, F) Radiographs after pin removal and measurements. Anteroposterior and lateral elbow radiographs at 6 months postoperatively showing fracture healing and radiological measurements of coronal and sagittal alignment.
Statistical analysis
Statistical analyses were performed using IBM SPSS Statistics version 27.0 (IBM Corp., Armonk, NY, USA). The distribution of continuous variables was assessed using the Shapiro–Wilk test. As the majority of variables did not demonstrate normal distribution, continuous variables are presented as median (25th–75th percentile) and mean values. Comparisons between the 2 groups were conducted using the Mann–Whitney U-test for continuous variables. Categorical variables were analyzed using the chi-square test or Fisher’s exact test when expected cell counts were low. Statistical significance was set at P < .05. Effect sizes for between-group comparisons were reported in the relevant tables. Additionally, to identify independent factors affecting elbow ROM, a multivariable analysis was performed using a multivariate linear regression model. All variables considered clinically relevant were included a priori in the multivariable models. Collinearity was assessed using variance inflation factors, and no significant collinearity was detected. Interobserver agreement for clinical and radiological measurements was analyzed using the intraclass correlation coefficient (ICC) for continuous variables and Cohen’s kappa coefficient for categorical variables. To minimize measurement bias in the final statistical analyses, measurements obtained by the senior orthopedic surgeon were used.
Results
A total of 95 pediatric patients with Gartland type 3 supracondylar humerus fractures were included in the analysis. Pins were removed at approximately the third postoperative week in 42 patients and at approximately the fifth week in 53 patients. Baseline demographic and surgical characteristics are summarized in Table 1. The 2 groups were comparable in age, time to surgery, sex distribution, number of pins, pin configuration, fracture displacement direction, and AHL alignment (all P > .05). The small effect sizes further support the comparability of the groups. Regarding complications, no major adverse events or loss of reduction were observed. Superficial pin-site erythema occurred in 1 patient in the third-week group and in 2 patients in the fifth-week group. No cases of deep infection were detected, and all cases resolved without the need for additional intervention.
Table 1.
Patient and surgical characteristics of the study groups
| Variable | 3-week group (n = 42) | 5-week group (n = 53) | P | Effect size |
|---|---|---|---|---|
| Age, years | 6 (5-8) (6.28) | 6 (4-8) (6.01) | .495 | 0.07 |
| Admission to surgery time, hours | 8 (6-10) (8.1) | 7 (6-9) (7.7) | .289 | 0.11 |
| Gender | .247 | 0.12 | ||
| Male (%) | 22 (52.4) | 34 (64.2) | ||
| Female (%) | 20 (47.6) | 19 (35.8) | ||
| Pin count | .887 | 0.02 | ||
| 3 pins (%) | 33 (78.6) | 41 (77.4) | ||
| 2 pins (%) | 9 (21.4) | 12 (22.6) | ||
| Pin configuration | .179 | 0.14 | ||
| Crossed (%) | 31 (73.8) | 45 (84.9) | ||
| Divergent lateral (%) | 11 (26.2) | 8 (15.1) | ||
| Displacement direction | .740 | 0.08 | ||
| Anterior (%) | 4 (9.5) | 3 (5.7) | ||
| Posteromedial (%) | 24 (57.1) | 30 (56.6) | ||
| Posterolateral (%) | 14 (33.3) | 20 (37.7) | ||
| Anterior humeral line position | .537 | 0.11 | ||
| Posterior third (%) | 2 (4.8) | 3 (5.7) | ||
| Middle third (%) | 28 (66.7) | 40 (75.5) | ||
| Anterior third (%) | 12 (28.6) | 10 (18.9) | ||
| Pin removal day, days | 23 (22-24) (23.0) | 37 (36-38) (37.4) | <.001 | 0.86 |
| Complication Pin-site erythema (%) | 1 (2.4) | 2 (3.8) | .70 | 0.04 |
Values are presented as the median (25th–75th percentile) (mean) for continuous variables and as a number (percentage) for categorical variables. Mann–Whitney U-test and chi-square tests were used. Effect sizes were calculated as r for Mann–Whitney U-tests and Cramér’s V for chi-square tests.
Radiological outcomes are summarized in Table 2. The RUST score at the time of pin removal was significantly higher in the fifth-week group compared with the third-week group (median: 10 vs. 9, P < .001), with a moderate effect size. However, no statistically significant differences were observed between the groups in RUST scores at the third- and sixth-month follow-up evaluations (P = .390 and P = .255, respectively).
Table 2.
Radiological outcomes according to pin removal timing
| Variable | 3-week group (n = 42) | 5-week group (n = 53) | P | Effect size |
|---|---|---|---|---|
| RUST score at pin removal | 9 (8-10) (8.9) | 10 (9-11) (10.0) | <.001 | 0.54 |
| RUST score at 3 months | 11 (11-12) (11.4) | 11 (11-12) (11.2) | .390 | 0.09 |
| RUST score at 6 months | 12 (12-12) (12.0) | 12 (12-12) (11.9) | .255 | 0.12 |
| Final Baumann angle, (°) | 74.5 (72-76) (74.0) | 75 (73-76.5) (74.6) | .271 | 0.11 |
| Anterior humeral line position | .131 | 0.20 | ||
| Posterior 1/3 (%) | 5 (11.9) | 9 (17.0) | ||
| Middle 1/3 (%) | 28 (66.7) | 40 (75.5) | ||
| Anterior 1/3 (%) | 9 (21.4) | 4 (7.5) |
Values are presented as the median (25th–75th percentile) (mean) for continuous variables and as a number (percentage) for categorical variables. Mann–Whitney U-test and chi-square or Fisher’s exact tests were used. Effect sizes were calculated as r for Mann–Whitney U-tests and Cramér’s V for chi-square tests.
RUST, Radiographic Union Score for Tibia.
There was no significant difference between the groups in terms of final Baumann angle measurements (P = .271). Similarly, the distribution of AHL alignment relative to the capitellum was comparable between the 2 groups (P = .131).
Clinical outcomes are presented in Table 3. At the third postoperative month, flexion loss and extension loss were significantly lower in the third-week pin removal group compared with the fifth-week group (P = .011 and P = .031, respectively). The effect sizes of these differences were small to moderate.
Table 3.
Clinical outcomes according to pin removal timing
| Variable | 3-week group (n = 42) | 5-week group (n = 53) | P | Effect size |
|---|---|---|---|---|
| Loss of flexion, third month (°) | 11 (5-15) (10.2) | 13 (9-16.5) (13.5) | .011 | 0.26 |
| Loss of extension, third month (°) | 6 (0-12) (6.5) | 9 (2-17) (9.7) | .031 | 0.22 |
| Loss of flexion, sixth month (°) | 1.5 (0-9) (4.2) | 5 (0-10) (5.5) | .197 | 0.13 |
| Loss of extension, sixth month (°) | 0 (0-3.3) (1.8) | 0 (0-3) (1.4) | .781 | 0.03 |
| Total motion loss (°) | 4 (0-10) (6.0) | 6 (1-11) (6.9) | .287 | 0.11 |
| Carrying angle difference (°) | −1 (−3 to 1) (−0.9) | 0 (−1.5 to 2) (−0.4) | .273 | 0.11 |
| Final Flynn score | .590 | 0.14 | ||
| Excellent (%) | 22 (52.4) | 25 (47.2) | ||
| Good (%) | 11 (26.2) | 13 (24.5) | ||
| Fair (%) | 6 (14.3) | 13 (24.5) | ||
| Poor (%) | 3 (7.1) | 2 (3.8) |
Values are presented as the median (25th–75th percentile) (mean) for continuous variables and as a number (percentage) for categorical variables. Mann–Whitney U-test and chi-square or Fisher’s exact tests were used. Effect sizes were calculated as r for Mann–Whitney U-tests and Cramér’s V for chi-square tests.
However, at the sixth-month follow-up, no statistically significant differences were observed between the groups in terms of flexion loss, extension loss, total ROM loss, or carrying angle difference (all P > .05). Final clinical outcomes evaluated according to the Flynn criteria were also comparable between the 2 groups (P = .590). In both groups, the majority of patients achieved excellent or good results, and the effect size for this comparison was small.
To confirm the findings of the univariate comparisons and to control for potential confounding factors, a multivariable linear regression analysis was performed (Table 4). The analysis demonstrated that pin removal timing was moderately associated with flexion and extension loss at the third postoperative month (P = .017 and P = .037, respectively). In contrast, at the sixth-month evaluation, pin removal timing was not found to have a significant independent effect on flexion or extension loss (all P > .05). None of the other clinical or radiological variables showed a significant independent association with ROM limitation.
Table 4.
Multivariable linear regression analysis of factors associated with elbow motion loss at 3 and 6 months
| Variable | 3-month flexion loss B (95% CI) | P | 3-month extension loss B (95% CI) | P | 6-month flexion loss B (95% CI) | P | 6-month extension loss B (95% CI) | P |
|---|---|---|---|---|---|---|---|---|
| Pin removal time (3 vs. 5 week) | 3.24 (0.62 to 5.86) | .017 | 3.35 (0.26 to 6.43) | .037 | 1.02 (−1.13 to 3.17) | .356 | −0.43 (−1.50 to 0.65) | .442 |
| Age (years) | −0.06 (−0.74 to 0.62) | .866 | 0.32 (−0.48 to 1.12) | .438 | 0.08 (−0.48 to 0.64) | .770 | 0.15 (−0.13 to 0.43) | .302 |
| Gender | −1.52 (−4.13 to 1.09) | .258 | −1.93 (−5.01 to 1.15) | .223 | −0.37 (−2.52 to 1.78) | .737 | −0.75 (−1.83 to 0.32) | .175 |
| Displacement direction | −0.70 (−2.93 to 1.53) | .539 | −0.72 (−3.35 to 1.90) | .591 | −0.18 (−2.01 to 1.66) | .852 | −0.75 (−1.67 to 0.17) | .112 |
| Time to surgery (hours) | −0.21 (−0.69 to 0.27) | .397 | −0.47 (−1.04 to 0.09) | .103 | −0.31 (−0.70 to 0.08) | .123 | −0.08 (−0.28 to 0.11) | .406 |
| Pin count | −0.12 (−3.24 to 3.00) | .939 | −2.02 (−5.70 to 1.66) | .285 | 0.88 (−1.68 to 3.45) | .501 | −0.43 (−1.72 to 0.86) | .511 |
| Pin configuration | 0.80 (−2.47 to 4.07) | .634 | 1.83 (−2.03 to 5.68) | .356 | 0.29 (−2.40 to 2.97) | .835 | −0.25 (−1.60 to 1.10) | .717 |
| Anterior humeral line position | −0.85 (−3.43 to 1.73) | .520 | −0.23 (−3.27 to 2.82) | .884 | −1.44 (−3.57 to 0.68) | .186 | 0.18 (−0.88 to 1.25) | .735 |
| Final Baumann angle | −0.17 (−0.69 to 0.36) | .531 | −0.32 (−0.94 to 0.30) | .313 | 0.08 (−0.36 to 0.51) | .731 | −0.03 (−0.25 to 0.19) | .774 |
Values are presented as unstandardized regression coefficients (B) with 95% CIs. A multivariable linear regression model was constructed for each outcome variable. Statistical significance was set at P < .05. Pin removal time was coded as early (3 weeks) vs. late (5 weeks).
Interobserver agreement for clinical and radiological measurements was found to be acceptable to excellent overall. Detailed ICC values are presented in Table 5.
Table 5.
Interobserver reliability of clinical and radiographic measurements
| Variable | ICC | 95% CI | P |
|---|---|---|---|
| Baumann angle | 0.852 | 0.786-0.899 | <.001 |
| RUST score at pin removal | 0.805 | 0.707-0.870 | <.001 |
| RUST score, third month | 0.899 | 0.848-0.933 | <.001 |
| RUST score, sixth month | 0.755 | 0.653-0.830 | <.001 |
| Flexion loss, third month | 0.811 | 0.716-0.874 | <.001 |
| Extension loss, third month | 0.885 | 0.802-0.930 | <.001 |
| Flexion loss, sixth month | 0.805 | 0.563-0.920 | <.001 |
| Extension loss, sixth month | 0.741 | 0.635-0.820 | <.001 |
| Carrying angle difference | 0.722 | 0.610-0.805 | <.001 |
Interobserver reliability was assessed using a 2-way mixed-effects model with absolute agreement. Values represent single-measure ICCs, with corresponding 95% CIs and P-values.
ICC, intraclass correlation coefficient; RUST, Radiographic Union Score for Tibia.
Discussion
The principal finding of this study is that pin removal performed at either the third or the fifth postoperative week resulted in comparable final radiological and functional outcomes. Removal at 3 weeks was not associated with loss of reduction, angular deformity, or reoperation, whereas removal at 5 weeks did not confer a long-term functional advantage. Although a small difference in elbow ROM was observed at 3 months, the magnitude of this difference was minimal and of limited clinical relevance; importantly, it resolved over time, with outcomes equalizing by 6 months and at final follow-up. Taken together, these findings suggest that pin removal within the commonly practiced 3-5 week interval yields similar overall results.
Radiographically, the RUST score was higher in the fifth-week group at the time of pin removal. This difference reflects the longer interval to assessment rather than a disparity in biological healing potential. Importantly, lower RUST values at 3 weeks were not associated with loss of reduction or inferior outcomes during follow-up, and subsequent evaluations demonstrated comparable union scores between groups.
Regarding complications, only superficial pin-site erythema was observed in both groups—2 cases in the fifth-week group and 1 case in the third-week group. All cases were resolved with local care without the need for additional intervention. No significant difference was identified between the groups in terms of pin-site complications, indicating that both pin removal timings demonstrated comparable safety profiles.
There is no universally accepted standard in the literature regarding the optimal timing of pin removal following CRPP for supracondylar humerus fractures. However, available studies consistently report that pins are typically removed between the third and fifth postoperative weeks. In a contemporary pediatric orthopedic series, pin removal was generally performed between 2.5 and 5 weeks after surgery.15 Similarly, a comprehensive review reported that pins are commonly left in situ for 3-5 weeks and recommended removal no later than 4-5 weeks to minimize the risk of infection.16 Zionts et al reported that pins were generally removed at around 3-4 weeks postoperatively7 whereas Pesenti et al reported that pin removal timing varied between 5 and 8 weeks.17 Likewise, a large retrospective cohort study found that pins were removed at a mean of 23 days postoperatively, corresponding approximately to the third to fourth week.18 Other studies evaluating postoperative protocols have reported similar time intervals. For instance, in a clinical series focusing on Gartland type 3 fractures, all patients underwent 3 weeks of immobilization, and pins were removed following radiographic evidence of union.19 In the present study, pins were removed at a median of approximately 23 days in the early group and 37 days in the late group. Both time points fall within the third-to-fifth-week interval commonly reported in the literature. Therefore, the protocols compared in this study reflect widely adopted clinical practices. From this perspective, the study provides a direct clinical comparison of the early and late boundaries of the pin removal interval suggested in the literature.
Restoration of elbow ROM is one of the most important indicators of functional recovery following supracondylar humerus fractures. The literature consistently reports that ROM improves progressively over time and that early motion limitations tend to diminish substantially in the long term. Zionts et al demonstrated that pins are typically removed at 3-4 weeks after percutaneous pinning and that, even without formal physiotherapy, elbow ROM recovered to 72% of the contralateral side at 6 weeks, 86% at 12 weeks, 94% at 26 weeks, and 98% at 52 weeks.7 Similarly, another study evaluating motion recovery after distal humerus fractures reported that elbow ROM improved considerably within a few weeks following immobilization.20 These findings indicate that early differences in motion tend to decrease over time. In the study, although the early pin removal group demonstrated better ROM at the third postoperative month, no difference was observed at the sixth month or at final follow-up, which is consistent with previous reports.
Carrying angle changes represent one of the most commonly evaluated coronal plane parameters following supracondylar fractures. Studies conducted in the normal pediatric population have shown that clinical carrying angle measurements correlate significantly with radiographic angular values and constitute a reliable clinical assessment tool.21 In a clinical series evaluating carrying angle changes together with functional outcomes after supracondylar fractures, satisfactory results were reported in all cases according to the Flynn criteria, and angular variations were generally found not to significantly affect daily function.22 In the study, carrying angle changes were minimal in both groups, with no statistically significant difference between them. Likewise, functional outcomes assessed using the Flynn criteria were predominantly excellent or good within the cohort, and no significant difference was observed between the groups. Although some studies have suggested that older children may exhibit relatively higher postoperative carrying angle values,23 no significant age difference was observed between the groups, thereby strengthening the validity of the comparison based on pin removal timing.
Supracondylar humerus fractures demonstrate a characteristic age distribution in childhood, and their biomechanical features vary with age. The literature reports a mean age of approximately 5-7 years, with the majority of cases occurring in children older than 3 years.24 Similarly, large pediatric series have shown that the peak incidence of supracondylar fractures occurs around 6 years of age, with most cases clustering in the early school-age period.1 In this age group, the physeal structure and ligamentous characteristics of the distal humerus give rise to typical pediatric fracture patterns. Moreover, it has been reported that even pronounced sagittal deformities may remodel in younger children, and treatment strategies are influenced by this biological potential.25 Clinical series likewise report a mean age of approximately 5 years, and most studies have been conducted in patient populations younger than 10 years.26 In contrast, patients older than 10 years are often analyzed separately in the literature as an adolescent group, as fracture morphology and treatment approaches in this age range may differ from those in younger children.27 For this reason, in order to obtain a homogeneous pediatric fracture pattern and to minimize the potential influence of adolescent-specific biomechanical and treatment-related differences, patients older than 10 years were excluded from the study. Accordingly, the study population consisted of children aged 3-10 years, consistent with the age distribution reported in the literature.
Although the RUST was originally developed for tibial fractures, it has recently been validated for use in pediatric supracondylar humerus fractures and has been reported as a reliable radiographic assessment tool.14 In addition, in the cohort, interobserver agreement for radiographic assessments was high, further supporting the consistency of union evaluation across groups. Therefore, RUST was used as a standardized and reproducible method to compare radiographic maturation between the 2 time points.
The AHL is one of the principal parameters used to assess sagittal-plane reduction quality on lateral radiographs in pediatric supracondylar humerus fractures. In a normal elbow, the AHL is expected to intersect the middle third of the capitellum, and disruption of this relationship has been associated with poorer early functional outcomes.28,29 Anterior humeral line assessment has been shown to have high interobserver agreement and reproducibility, and more recently described quantitative measurement approaches have enabled more objective evaluation of sagittal-plane reduction quality.30 In the study, the distribution of AHL alignment was similar between the groups, suggesting comparable baseline sagittal reduction quality and supporting the validity of comparing outcomes according to pin removal timing.
There is still no consensus in the literature regarding the optimal number and configuration of pins in pediatric supracondylar humerus fractures, and numerous biomechanical and clinical studies have addressed this issue.31-34 Several studies have reported comparable functional and radiological outcomes between crossed and lateral-only pinning techniques, indicating that pin selection often depends on surgeon preference.35 However, biomechanical studies frequently suggest that the classic crossed-pin configuration provides greater stability, particularly under torsional loading conditions.34 Likewise, some reports emphasize that optimizing pin number and placement geometry may enhance stability, and configurations involving crossed pins or medial column capture may be advantageous.36 In the cohort, traditional crossed-pin and 3-pin configurations were predominantly used. Importantly, the distributions of pin numbers and configurations were similar between the groups, thereby reducing potential configuration-related bias and allowing for a more objective assessment of the effect of pin removal timing on outcomes.
One of the major strengths of this study is that it was conducted in a high-volume pediatric trauma center with a homogeneous patient population. Inclusion of only completely displaced Gartland type 3 fractures minimized fracture-type–related heterogeneity between the groups. Furthermore, all procedures were performed by experienced trauma surgeons, contributing to procedural consistency across the cohort. Clinical and radiological measurements were independently performed by 2 senior orthopedic surgeons, and interobserver reliability analyses were conducted, further strengthening the methodological robustness of the study. To the best of current knowledge, this study is among the first to compare the clinical and radiological effects of different pin removal timings within a homogeneous cohort of patients with Gartland type 3 supracondylar humerus fractures.
This study has several limitations that should be acknowledged. First, its retrospective design and single-center setting may limit generalizability. Second, pin removal timing was determined according to surgeons’ routine outpatient follow-up practices rather than randomization, which may have introduced selection bias and confounding by indication. In addition, surgeon-level clustering and potential surgeon-specific treatment patterns were not formally modeled. Although perioperative management and postoperative rehabilitation protocols were standardized across the institution, residual confounding cannot be fully excluded. Third, although the sample size was sufficient to detect differences in radiological and functional outcomes, the study may be underpowered to identify small differences in parameters. Additionally, as cases with early mechanical complications were excluded, the findings should be interpreted in the context of uncomplicated fractures. Furthermore, fractures were classified up to Gartland type 3, and Gartland type 4 injuries were not separately evaluated; therefore, the findings may not be directly applicable to this subgroup. Finally, in the clinical practice, intraoperative fluoroscopic dynamic assessment is routinely performed after K-wire fixation, and the present cohort represents cases without observable instability during this evaluation. Although this approach helped exclude cases with gross instability, subtle variability in fixation stability may still have existed among included cases. However, as these assessments were not recorded as objective imaging data, they could not be quantitatively analyzed, which represents a limitation of the study.
In this cohort of pediatric patients with Gartland type 3 supracondylar humerus fractures treated with CRPP, no meaningful differences in radiological or functional outcomes were observed between pin removal at the third and fifth postoperative weeks. Although minor early differences in elbow ROM were observed, these diminished over time. These findings suggest that, in appropriately selected patients with stable fixation and close follow-up, pin removal timing may be individualized between the third and fifth postoperative weeks without substantially affecting mid-term elbow recovery.
Funding Statement
The authors declared that this study has received no financial support.
Footnotes
Artificial Intelligence Usage Statement: The authors declared that no Artificial Intelligence tool was used in the preparation of the manuscript.
Ethics Committee Approval: Ethical committee approval was received from the Medical Sciences Ethics Committee of Health Sciences University Bursa Yüksek İhtisas Training and Research Hospital (Approval no: 2024-TBEK 2026/02-16, Date: February 12, 2026).
Informed Consent: Written informed consent was obtained from the patients who agreed to take part in the study.
Peer-review: Externally peer-reviewed.
Author Contributions: Concept – N.C., Y.A.; Design – N.C.; Supervision – N.C., Y.A., H.Y., A.O.; Resources – N.C., H.C.B; Materials – O.A.; Data Collection and/or Processing – N.C., H.C.B., O.A., M.G.; Analysis and/or Interpretation – H.C.B.; Literature Search – N.C., H.C.B; Writing – N.C., H.C.B.; Critical Review – N.C., Y.A., H.C.B., O.A., H.Y., A.O.
Declaration of Interests: The authors have no conflict of interest to declare.
Data Availability Statement:
The data that support the findings of this study are available on request from the corresponding author.
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Associated Data
This section collects any data citations, data availability statements, or supplementary materials included in this article.
Data Availability Statement
The data that support the findings of this study are available on request from the corresponding author.