Abstract
Background
Minimally displaced intra-articular calcaneal fractures are commonly managed with cast immobilization, but prolonged immobilization may delay recovery and contribute to hindfoot stiffness. This study compared mid-term clinical and radiographic outcomes of two institutional protocols for minimally displaced Sanders type II–III calcaneal fractures: closed reduction and percutaneous screw fixation with earlier range-of-motion exercises versus cast immobilization.
Methods
This two-center retrospective cohort study included 87 patients treated between January 2018 and February 2024 with a minimum 24-month follow-up. Fifty-three patients underwent closed reduction and percutaneous fixation using two 5-mm headless cannulated screws, with range-of-motion exercises beginning at 2 weeks. Thirty-four patients were treated nonoperatively with short-leg cast immobilization for 6 weeks. The primary outcome was the Foot and Ankle Ability Measure (FAAM), including Activities of Daily Living and Sports subscales. Secondary outcomes included the AOFAS Ankle-Hindfoot score, visual analog scale pain score, and serial radiographic measurements.
Results
Pre-treatment demographic, fracture, follow-up, and radiographic characteristics were comparable between groups. At final follow-up, the fixation and earlier rehabilitation protocol was associated with higher FAAM Activities of Daily Living, FAAM Sports, and AOFAS scores. VAS pain was lower in unadjusted analysis but was not significant after adjustment. Final Böhler and Gissane angles were higher in the fixation group. The fixation group also showed greater calcaneal height increase and calcaneal length decrease from pre-treatment to final follow-up. All fractures united. No wound-healing complications or surgical-site infections occurred after fixation; posterior implant-entry-site irritation occurred in three patients and required implant removal after union.
Conclusion
In selected minimally displaced Sanders type II–III calcaneal fractures, the institutional protocol including closed reduction, percutaneous screw fixation, and earlier rehabilitation was associated with better mid-term functional outcomes and more favorable radiographic parameters than cast immobilization. Prospective comparative studies are needed to evaluate fixation, cast immobilization, and functional nonoperative rehabilitation strategies.
Supplementary Information
The online version contains supplementary material available at 10.1186/s12891-026-10166-8.
Keywords: Calcaneus fracture, Sanders classification, Percutaneous fixation, Cannulated screw, Cast treatment, Early mobilization, FAAM, AOFAS
Introduction
Calcaneal fractures are the most common hindfoot fractures and may result in persistent pain, stiffness, and functional limitation when hindfoot alignment and subtalar mechanics are not adequately restored. Management remains controversial and is generally individualized according to fracture morphology, displacement, soft-tissue condition, patient factors, and radiographic parameters such as the Böhler and Gissane angles [1].
Minimally displaced intra-articular calcaneal fractures, including selected Sanders type II–III fractures without severe collapse, are frequently treated nonoperatively to avoid surgical morbidity. However, cast immobilization may delay mobilization and contribute to hindfoot stiffness, whereas minimally invasive fixation strategies may allow earlier motion with limited soft-tissue disruption [2].
Previous randomized trials and systematic reviews have reported mixed results for operative versus nonoperative treatment of displaced intra-articular calcaneal fractures [3–6]. More recent studies have focused on minimally invasive or percutaneous approaches, which have been reported to reduce wound-related complications while maintaining acceptable radiographic and functional outcomes in selected patients [7–17]. Nevertheless, comparative data for minimally displaced Sanders type II–III fractures remain limited.
Therefore, the aim of this two-center retrospective comparative study was to compare the mid-term clinical and radiographic outcomes of two institutional treatment protocols: closed reduction and percutaneous screw fixation followed by earlier range-of-motion exercises versus cast immobilization. We hypothesized that the fixation and earlier rehabilitation protocol would be associated with better final functional outcomes and more favorable radiographic parameters than cast immobilization in this selected patient population.
Materials and methods
Study design and patient population
This two-center retrospective comparative study included patients with minimally displaced intra-articular calcaneal fractures classified as Sanders type II or III who were treated between January 2018 and February 2024. The study compared two predefined institutional treatment protocols: closed reduction and percutaneous screw fixation followed by earlier range-of-motion exercises at Center A, and nonoperative short-leg cast immobilization at Center B. Because treatment allocation was center-based, the comparison was interpreted as a retrospective comparison of two institutional treatment protocols.
Minimally displaced fractures were defined as posterior facet step-off < 2 mm on pre-treatment computed tomography, Böhler angle reduction ≤ 10° compared with the uninjured contralateral side, and absence of gross calcaneal widening, defined as > 15% widening compared with the uninjured contralateral side. Standardized radiographs of the injured and uninjured hindfeet were reviewed for the relative angular and dimensional comparisons. Severe radiographic collapse was defined as an absolute Böhler angle < 0° or comminution precluding meaningful articular reconstruction.
Patients were included if pre-treatment radiographs and computed tomography demonstrated a Sanders type II–III fracture without severe radiographic collapse or gross calcaneal malalignment, if pre-treatment, early post-treatment, and final follow-up radiographs were available, and if clinical outcome scores were recorded at a minimum follow-up of 24 months. Patients with bilateral calcaneal fractures were excluded to preserve the independence of observations. Baseline demographic and clinical characteristics, including age, sex, smoking status, and diabetes mellitus, were obtained from electronic medical records. The study protocol was approved by the Medical Research Ethics Committee of Izmir City Hospital (Approval No: 2026/244), which waived the requirement for written informed consent because of the retrospective design.
Treatment protocols
Percutaneous fixation group
Patients underwent closed reduction and percutaneous fixation using two 5-mm headless cannulated compression screws (Omega Ortopedik Sistemler, Izmir, Türkiye). Under fluoroscopic guidance, closed reduction was performed using manual traction, correction of varus-valgus malalignment, restoration of hindfoot alignment, and lateral wall molding when required. After satisfactory reduction had been achieved, two cannulated compression screws were inserted percutaneously from the posterior calcaneal tuberosity. One screw was directed toward the sustentaculum tali and the other toward the anterior process/subchondral region of the posterior facet, according to the fracture configuration. Screw position, posterior facet alignment, and hindfoot morphology were checked fluoroscopically. A short-leg splint was applied for 2 weeks. Passive and active ankle and subtalar range-of-motion exercises were initiated at 2 weeks under physiotherapist supervision. Partial weight bearing was allowed at 6 weeks, and full weight bearing at 10 weeks if progressive fracture healing was evident. A representative radiographic course of a patient treated with closed reduction and percutaneous screw fixation is shown in Fig. 1.
Fig. 1.
Representative images of a patient treated with closed reduction and percutaneous screw fixation for a minimally displaced intra-articular calcaneal fracture. a Pre-treatment lateral radiograph. b Pre-treatment computed tomography images demonstrating intra-articular extension of the fracture line involving the posterior facet. c Early postoperative lateral radiograph after closed reduction and percutaneous fixation with two 5-mm headless cannulated compression screws. d Final follow-up lateral radiograph showing maintained alignment and preservation of calcaneal morphology without loss of reduction
Cast treatment group
Patients were managed nonoperatively according to the institutional cast immobilization protocol and remained non-weight-bearing for 6 weeks. During the first 3 weeks, a short-leg cast was applied with the ankle in slight equinus/plantar flexion and was changed weekly to accommodate soft-tissue swelling and allow skin monitoring. At 3 weeks, the cast was changed to a short-leg cast in neutral ankle position and maintained for an additional 3 weeks. After cast removal, ankle and subtalar range-of-motion exercises and partial weight bearing were initiated under physiotherapy guidance. Full weight bearing was allowed at 10 weeks, consistent with the percutaneous fixation protocol. A representative radiographic course of a patient managed with cast immobilization is shown in Fig. 2.
Fig. 2.
Representative radiographic images of a patient managed nonoperatively with cast treatment. a Pre-treatment lateral radiograph showing a minimally displaced intra-articular calcaneal fracture. b Early post-treatment lateral radiograph obtained after initial short-leg cast application, demonstrating conservative maintenance of calcaneal alignment. c Final follow-up lateral radiograph after cast treatment showing fracture union and preserved overall calcaneal morphology without gross collapse
Clinical outcome assessment
The primary clinical outcome was the Foot and Ankle Ability Measure (FAAM), including the Activities of Daily Living and Sports subscales, expressed as percentage scores from 0 to 100. Secondary clinical outcomes included the American Orthopaedic Foot & Ankle Society (AOFAS) Ankle-Hindfoot score and pain severity measured using a 10-point visual analog scale. All clinical outcomes were assessed at final follow-up by an independent observer not involved in treatment.
Radiographic assessment
Radiographic evaluation was performed using pre-treatment, early post-treatment, and final follow-up images. Early post-treatment radiographs were obtained within 48 h postoperatively in the percutaneous fixation group and after initial cast application in the cast treatment group. Standardized lateral and axial calcaneal views were obtained whenever feasible. In the cast group, early post-treatment radiographs were obtained while the ankle was immobilized in slight equinus/plantar flexion; therefore, neutral foot position could not be ensured at this time point. Final follow-up radiographs were obtained after cast removal with the foot in neutral position.
Radiographic parameters included the Böhler and Gissane angles, as well as calcaneal height, length, and width. On lateral radiographs, the Böhler angle was measured as the angle between a line connecting the highest point of the anterior process to the highest point of the posterior facet and a line connecting the highest point of the posterior facet to the superior point of the calcaneal tuberosity. The Gissane angle was measured as the angle formed by the downward and upward slopes of the superior calcaneal surface. Calcaneal height was measured on the lateral view as the maximum perpendicular distance between the inferior calcaneal border and the highest point of the superior calcaneal contour. Calcaneal length was measured on the lateral view as the maximum distance from the most posterior point of the tuberosity to the most anterior point of the anterior process. Calcaneal width was measured on the axial calcaneal view as the maximum mediolateral width of the calcaneus. For each parameter, early post-treatment correction, late change from early post-treatment to final follow-up, and net change from pre-treatment to final follow-up were calculated.
All radiographic measurements were performed independently by two experienced orthopaedic surgeons who were blinded to clinical outcomes and to each other’s measurements. Because fixation implants were visible on postoperative and follow-up radiographs, complete blinding to treatment allocation was not feasible. The mean of the two measurements was used for analysis. To assess intraobserver reliability, one observer repeated measurements in a randomly selected subset of 20 patients, including 10 from each treatment group, after a 4-week interval. Interobserver reliability was assessed using the initial measurements of the two observers. Reliability was evaluated using the intraclass correlation coefficient with a two-way random-effects model for absolute agreement.
Union and complications
Fracture union was assessed on serial follow-up radiographs by the treating surgeon. Union was defined as bridging trabeculae across the fracture site on at least two views, absence of a visible fracture line, and absence of pain on weight bearing. Complications were recorded from medical records and follow-up visits and included delayed union, nonunion, wound-healing problems, superficial or deep surgical-site infection, implant-related irritation, and secondary procedures such as implant removal, debridement, or arthrodesis.
No patient received bone grafting, calcium phosphate augmentation, or other bone substitute materials during the initial treatment period. No patient in the percutaneous fixation group required conversion to open reduction, and no patient in the cast treatment group crossed over to surgical treatment during follow-up.
Statistical analysis
Statistical analyses were performed using IBM SPSS Statistics for Windows, version 26.0. Categorical variables were summarized as counts and percentages, and continuous variables as mean ± standard deviation or median with interquartile range, as appropriate. Normality was assessed using the Shapiro–Wilk test. Between-group comparisons were performed using the Mann-Whitney U test, chi-square test, or Fisher’s exact test, as appropriate. Within-group longitudinal radiographic changes were evaluated using the Wilcoxon signed-rank test.
Multivariable linear regression models were used to evaluate adjusted group effects for the main clinical outcomes and selected final radiographic outcomes, with treatment group as the main predictor. The primary adjusted model included age and sex, and the fully adjusted model additionally included smoking status and diabetes mellitus. Heteroscedasticity-consistent robust standard errors were used. Center was not included as a covariate because treatment group and center were perfectly collinear. No adjustment was made for multiple comparisons; therefore, secondary and exploratory analyses were considered exploratory. A two-sided p-value < 0.05 was considered statistically significant.
Results
Demographic and fracture characteristics
A total of 87 patients were included, with 53 in the percutaneous fixation group and 34 in the cast treatment group. Baseline demographic, clinical, fracture, and follow-up characteristics were comparable between groups (Table 1).
Table 1.
Baseline demographic and clinical characteristics
| Variable | Percutaneous fixation (n = 53) | Cast treatment (n = 34) |
p-value |
|---|---|---|---|
| Age, years | 40.0 (35.0–45.0) | 43.0 (38.2–48.5) | 0.194 |
| Male sex, n (%) | 42 (79.2) | 30 (88.2) | 0.428 |
| Female sex, n (%) | 11 (20.8) | 4 (11.8) | |
| Current smoker, n (%) | 18 (34.0) | 12 (35.3) | 1.000 |
| Diabetes mellitus, n (%) | 13 (24.5) | 10 (29.4) | 0.799 |
| Right-sided fracture, n (%) | 27 (50.9) | 17 (50.0) | 1.000 |
| Left-sided fracture, n (%) | 26 (49.1) | 17 (50.0) | |
| Sanders type II, n (%) | 36 (67.9) | 19 (55.9) | 0.364 |
| Sanders type III, n (%) | 17 (32.1) | 15 (44.1) | |
| Follow-up duration, months | 45.0 (36.0–75.0) | 51.0 (40.5–64.5) | 0.828 |
Data are presented as median (interquartile range) or number (percentage), as appropriate. Between-group comparisons were performed using the Mann-Whitney U test for continuous variables and the chi-square or Fisher’s exact test for categorical variables, as appropriate
IQR interquartile range
Radiographic outcomes
Pre-treatment Böhler and Gissane angles, as well as calcaneal height, length, and width, were not significantly different between groups (Table 2). Early post-treatment and final follow-up Böhler and Gissane angles were significantly more favorable in the percutaneous fixation group.
Table 2.
Comparison of radiographic parameters between groups
| Radiographic parameter | Percutaneous fixation (n = 53) |
Cast treatment (n = 34) |
p-value |
|---|---|---|---|
| Böhler angle, pre-treatment (°) | 14.0 (14.0–16.0) | 14.0 (10.0–20.8) | 0.403 |
| Böhler angle, early post-treatment (°) | 25.0 (23.0–29.0) | 17.5 (15.0–25.0) | < 0.001 |
| Böhler angle, final follow-up (°) | 24.0 (22.0–25.0) | 15.5 (9.5–23.0) | < 0.001 |
| Böhler angle final–pre change (°) | 8.0 (6.0–11.0) | 1.5 (-0.8–3.0) | < 0.001 |
| Gissane angle, pre-treatment (°) | 120.0 (115.0–132.0) | 122.5 (118.2–128.8) | 0.783 |
| Gissane angle, early post-treatment (°) | 133.0 (132.0–136.0) | 125.0 (120.5–128.8) | < 0.001 |
| Gissane angle, final follow-up (°) | 130.0 (129.0–135.0) | 120.0 (117.0–124.8) | < 0.001 |
| Gissane angle final–pre change (°) | 7.0 (7.0–15.0) | -4.0 (-5.0–0.5) | < 0.001 |
| Calcaneal height, pre-treatment (mm) | 41.0 (35.8–42.2) | 42.0 (37.5–43.0) | 0.878 |
| Calcaneal height, early post-treatment (mm) | 43.0 (40.6–46.2) | 43.0 (39.0–44.0) | 0.031 |
| Calcaneal height, final follow-up (mm) | 42.5 (40.5–46.0) | 42.0 (38.2–43.0) | 0.004 |
| Calcaneal height final–pre change (mm) | 2.4 (1.9–3.0) | 0.0 (0.0–0.0) | < 0.001 |
| Calcaneal length, pre-treatment (mm) | 81.5 (80.0–83.5) | 80.0 (79.0–82.0) | 0.075 |
| Calcaneal length, early post-treatment (mm) | 78.0 (77.0–82.0) | 80.0 (79.0–83.0) | 0.014 |
| Calcaneal length, final follow-up (mm) | 79.5 (77.3–82.0) | 80.5 (78.0–83.0) | 0.229 |
| Calcaneal length final–pre change (mm) | -2.1 (-2.9 to -2.0) | 0.0 (0.0–1.0) | < 0.001 |
| Calcaneal width, pre-treatment (mm) | 39.0 (36.8–40.0) | 38.0 (35.0–39.0) | 0.079 |
| Calcaneal width, early post-treatment (mm) | 39.5 (37.0–40.0) | 38.0 (34.0–39.0) | 0.020 |
| Calcaneal width, final follow-up (mm) | 39.0 (37.0–39.8) | 38.0 (35.0–38.0) | 0.009 |
| Calcaneal width final–pre change (mm) | 0.1 (0.0–0.4) | 0.0 (0.0–0.0) | < 0.001 |
Data are presented as median (interquartile range). Between-group comparisons were performed using the Mann–Whitney U test. Only pre-treatment, early post-treatment, final follow-up, and change from pre-treatment to final follow-up values are shown to emphasize the main radiographic findings. Negative change values indicate a decrease from pre-treatment to final follow-up. Calcaneal height and length changes were interpreted as secondary descriptive radiographic parameters
Linear radiographic measurements showed descriptive differences between the two treatment protocols. The percutaneous fixation group showed a greater increase in calcaneal height and a greater decrease in calcaneal length from pre-treatment to final follow-up, whereas final calcaneal length did not differ significantly between groups (Table 2).
Within-group radiographic changes are summarized in Table 3. The percutaneous fixation group demonstrated early radiographic correction that was largely maintained at final follow-up.
Table 3.
Within-group comparison of radiographic parameters over time
| Parameter | Group | Pre-treatment | Early post-treatment | Final follow-up | Pre vs. early p | Early vs. final p | Pre vs. final p |
|---|---|---|---|---|---|---|---|
| Böhler angle (°) | Percutaneous fixation | 14.0 (14.0–16.0) | 25.0 (23.0–29.0) | 24.0 (22.0–25.0) | < 0.001 | < 0.001 | < 0.001 |
| Böhler angle (°) | Cast treatment | 14.0 (10.0–20.8) | 17.5 (15.0–25.0) | 15.5 (9.5–23.0) | < 0.001 | < 0.001 | 0.091 |
| Gissane angle (°) | Percutaneous fixation | 120.0 (115.0–132.0) | 133.0 (132.0–136.0) | 130.0 (129.0–135.0) | < 0.001 | < 0.001 | < 0.001 |
| Gissane angle (°) | Cast treatment | 122.5 (118.2–128.8) | 125.0 (120.5–128.8) | 120.0 (117.0–124.8) | < 0.001 | < 0.001 | 0.031 |
| Calcaneal height (mm) | Percutaneous fixation | 41.0 (35.8–42.2) | 43.0 (40.6–46.2) | 42.5 (40.5–46.0) | < 0.001 | < 0.001 | < 0.001 |
| Calcaneal height (mm) | Cast treatment | 42.0 (37.5–43.0) | 43.0 (39.0–44.0) | 42.0 (38.2–43.0) | < 0.001 | < 0.001 | 0.005 |
| Calcaneal length (mm) | Percutaneous fixation | 81.5 (80.0–83.5) | 78.0 (77.0–82.0) | 79.5 (77.3–82.0) | < 0.001 | < 0.001 | < 0.001 |
| Calcaneal length (mm) | Cast treatment | 80.0 (79.0–82.0) | 80.0 (79.0–83.0) | 80.5 (78.0–83.0) | 0.009 | 0.157 | 0.127 |
| Calcaneal width (mm) | Percutaneous fixation | 39.0 (36.8–40.0) | 39.5 (37.0–40.0) | 39.0 (37.0–39.8) | 0.515 | 0.093 | 0.002 |
| Calcaneal width (mm) | Cast treatment | 38.0 (35.0–39.0) | 38.0 (34.0–39.0) | 38.0 (35.0–38.0) | 0.019 | 0.180 | 0.034 |
Data are presented as median (interquartile range). The Wilcoxon signed-rank test was used for paired within-group comparisons
Measurement reliability
Radiographic measurement reliability for the predefined angular and linear parameters was good to excellent. The intraobserver ICC was 0.92 (95% CI: 0.87–0.95) for the Böhler angle, 0.89 (95% CI: 0.83–0.93) for the Gissane angle, 0.93 (95% CI: 0.88–0.95) for calcaneal height, 0.91 (95% CI: 0.87–0.94) for calcaneal length, and 0.89 (95% CI: 0.82–0.92) for calcaneal width. The interobserver ICC was 0.88 (95% CI: 0.81–0.92) for the Böhler angle, 0.85 (95% CI: 0.77–0.90) for the Gissane angle, 0.89 (95% CI: 0.85–0.91) for calcaneal height, 0.86 (95% CI: 0.78–0.89) for calcaneal length, and 0.87 (95% CI: 0.84–0.92) for calcaneal width.
Clinical outcomes
At final follow-up, FAAM Activities of Daily Living, FAAM Sports, and AOFAS scores were significantly higher in the closed reduction and percutaneous fixation with earlier rehabilitation group than in the cast immobilization group (Table 4). VAS pain scores were lower in the percutaneous fixation group in the unadjusted comparison.
Table 4.
Comparison of clinical outcomes between groups
| Clinical outcome | Percutaneous fixation (n = 53) | Cast treatment (n = 34) | p-value |
|---|---|---|---|
| FAAM ADL score | 100.0 (97.6–100.0) | 88.7 (69.6–98.5) | < 0.001 |
| FAAM Sports score | 96.9 (93.8–100.0) | 79.7 (63.3–93.8) | < 0.001 |
| AOFAS Ankle-Hindfoot score | 95.0 (90.0–100.0) | 85.0 (73.0–90.0) | < 0.001 |
| VAS pain score | 2.0 (2.0–3.0) | 3.0 (2.0–4.0) | 0.032 |
Data are presented as median (interquartile range). Between-group comparisons were performed using the Mann-Whitney U test
FAAM Foot and Ankle Ability Measure, ADL Activities of Daily Living, AOFAS American Orthopaedic Foot & Ankle Society, VAS visual analog scale
Adjusted clinical and radiographic analyses
In both age- and sex-adjusted and fully adjusted linear regression models, the treatment protocol including closed reduction, percutaneous fixation, and earlier rehabilitation remained associated with higher FAAM Activities of Daily Living, FAAM Sports, and AOFAS scores (Table 5). The adjusted association with VAS pain was not statistically significant.
Table 5.
Adjusted group effects for clinical outcomes
| Outcome | Adjusted group effect for percutaneous fixation vs. cast | 95% CI | p-value |
|---|---|---|---|
| FAAM ADL score | 13.16 | 6.40 to 19.92 | < 0.001 |
| FAAM Sports score | 16.82 | 8.56 to 25.09 | < 0.001 |
| AOFAS Ankle-Hindfoot score | 8.65 | 2.24 to 15.05 | 0.008 |
| VAS pain score | -0.49 | -1.12 to 0.13 | 0.123 |
Values represent adjusted group effects from Model 2 for percutaneous fixation relative to cast treatment. Model 2 was adjusted for age, sex, smoking status, and diabetes mellitus. HC3 robust standard errors were used. Positive values indicate higher scores in the percutaneous fixation group, whereas negative values indicate lower scores
CI confidence interval, FAAM Foot and Ankle Ability Measure, ADL Activities of Daily Living, AOFAS American Orthopaedic Foot & Ankle Society, VAS visual analog scale
Adjusted radiographic analyses are summarized in Table 6. Compared with cast immobilization, the closed reduction and percutaneous fixation protocol remained associated with higher final Böhler and Gissane angles and greater changes in both angles from pre-treatment to final follow-up. The protocol was also associated with greater calcaneal height increase and greater calcaneal length decrease from pre-treatment to final follow-up, while final calcaneal length was not significantly different between groups after adjustment.
Table 6.
Adjusted group effects for radiographic outcomes
| Outcome | Adjusted group effect for percutaneous fixation vs. cast | 95% CI | p-value |
|---|---|---|---|
| Final Böhler angle (°) | 7.17 | 4.23 to 10.11 | < 0.001 |
| Final-pre Böhler change (°) | 7.15 | 5.31 to 8.99 | < 0.001 |
| Final Gissane angle (°) | 9.74 | 5.74 to 13.74 | < 0.001 |
| Final-pre Gissane change (°) | 9.33 | 5.72 to 12.94 | < 0.001 |
| Final calcaneal height (mm) | 2.55 | 0.84 to 4.25 | 0.003 |
| Final-pre calcaneal height change (mm) | 2.55 | 2.10 to 2.99 | < 0.001 |
| Final calcaneal length (mm) | -0.39 | -1.90 to 1.12 | 0.615 |
| Final-pre calcaneal length change (mm) | -2.41 | -2.86 to -1.96 | < 0.001 |
| Final calcaneal width (mm) | 1.70 | 0.50 to 2.91 | 0.005 |
| Final-pre calcaneal width change (mm) | 0.50 | 0.26 to 0.73 | < 0.001 |
Values represent adjusted group effects from the fully adjusted model for percutaneous fixation relative to cast treatment. The model was adjusted for age, sex, smoking status, and diabetes mellitus. HC3 robust standard errors were used. Positive values indicate higher final radiographic values or greater change in the percutaneous fixation group, whereas negative values indicate lower values or greater decrease. Height and length changes were interpreted as secondary descriptive radiographic outcomes rather than evidence of a compression-mediated mechanism
CI confidence interval
AOFAS component scores
In exploratory component-level analysis, the percutaneous fixation group had a higher proportion of patients achieving maximum scores in several AOFAS domains, particularly pain, activity limitation/support, walking distance, walking surfaces, sagittal motion, hindfoot motion, and alignment. Gait abnormality and stability did not differ between groups (Supplementary Table 1). These analyses were exploratory and were not adjusted for multiple comparisons.
Union and complications
All fractures achieved radiographic union, and no nonunion was observed in either group. In the percutaneous fixation group, no wound-healing problems or superficial or deep surgical-site infections occurred. Posterior implant-entry-site irritation was observed in three patients (5.7%), all of whom underwent implant removal after confirmed radiographic union. No patient received bone grafting or other augmentation procedures, and no crossover from cast treatment to surgical intervention occurred during follow-up.
Discussion
The main finding of this two-center retrospective comparative study is that, in selected minimally displaced Sanders type II-III intra-articular calcaneal fractures, the institutional protocol including closed reduction, percutaneous screw fixation, and earlier rehabilitation was associated with better mid-term functional outcomes and more favorable radiographic parameters than cast immobilization. The differences were most evident in FAAM ADL, FAAM Sports, AOFAS scores, and final Böhler and Gissane angles. All fractures united, and no wound-healing complications or surgical-site infections were observed in the fixation group. These findings suggest that, in carefully selected fractures without severe collapse, a less invasive fixation strategy combined with earlier mobilization may offer clinically relevant advantages over prolonged cast immobilization.
The management of intra-articular calcaneal fractures remains controversial, especially in fractures with limited displacement. Traditional nonoperative treatment avoids surgical morbidity but usually requires prolonged immobilization, which may contribute to hindfoot stiffness and delayed functional recovery. Conversely, open reduction and internal fixation may improve alignment but carries a higher risk of wound-related complications, particularly with extensile approaches. Previous randomized trials and systematic reviews have reported mixed results regarding the benefit of operative treatment over nonoperative care, and the certainty of evidence remains limited [3–6]. In this context, percutaneous and minimally invasive techniques have gained increasing interest because they aim to improve or maintain calcaneal morphology while limiting soft-tissue disruption [7–14].
The radiographic findings support the potential benefit of closed reduction and percutaneous stabilization in maintaining calcaneal morphology. Pre-treatment radiographic parameters were comparable between groups, whereas final Böhler and Gissane angles were more favorable in the fixation group. The fixation group also demonstrated greater restoration of calcaneal height and a greater decrease in calcaneal length from pre-treatment to final follow-up. These changes should be interpreted as radiographic differences associated with the overall treatment protocol rather than as evidence of a single mechanical effect of screw fixation. In clinical terms, the findings suggest that closed reduction, restoration of hindfoot alignment, and percutaneous screw stabilization may help maintain sagittal calcaneal morphology during healing. This interpretation is consistent with previous reports supporting percutaneous or fracture-specific minimally invasive strategies in selected Sanders type II–III fractures [15, 16].
The functional findings are also clinically relevant. The fixation and earlier rehabilitation group achieved higher FAAM ADL and FAAM Sports scores at final follow-up. The FAAM Sports subscale may be particularly informative in this cohort because minimally displaced fractures often occur in patients who retain relatively high baseline function, and residual activity-related limitations may not be fully captured by more general scores. The difference in AOFAS scores was consistent with the FAAM findings, although the AOFAS score was interpreted as a secondary outcome. VAS pain was lower in the fixation group in the unadjusted comparison but was not significant after adjustment, suggesting that the main clinical difference may relate more to function and activity tolerance than to pain alone. These findings are broadly consistent with recent comparative evidence suggesting that minimally invasive surgery may provide selected functional advantages over nonoperative treatment in appropriately selected calcaneal fractures [17].
The better outcomes in the fixation group may reflect the combined effects of reduction, internal stabilization, and earlier rehabilitation. In the fixation group, range-of-motion exercises were started at 2 weeks, whereas the cast group remained immobilized for 6 weeks. Therefore, the present study cannot determine whether the observed functional advantage was primarily due to fixation, earlier mobilization, or their combination. Nevertheless, this distinction is clinically meaningful because treatment decisions in daily practice are often made at the protocol level rather than as isolated interventions. The findings suggest that protocols allowing stable fixation and earlier motion may be advantageous in selected patients, but prospective studies are needed to determine whether similar outcomes could be achieved with functional nonoperative treatment or shorter immobilization.
The safety profile of the percutaneous fixation protocol was favorable in this cohort. All fractures achieved union, and no wound-healing problems, superficial infections, or deep infections occurred after fixation. The only implant-related complication was posterior implant-entry-site irritation in three patients, all of whom underwent implant removal after union. This complication is relevant for patient counseling but appears less severe than the wound complications commonly associated with more invasive approaches. Previous studies comparing minimally invasive or limited approaches with extensile lateral fixation have similarly emphasized the soft-tissue advantages of less invasive strategies [18, 19]. Other clinical studies of closed, percutaneous, or screw-based fixation techniques have also reported satisfactory outcomes in selected intra-articular calcaneal fractures [20–24]. These findings support the potential role of percutaneous fixation as a soft-tissue-preserving option in appropriately selected fractures, while acknowledging that implant-entry-site irritation may still require secondary removal.
An important distinction of the present study is that it compared two institutional treatment protocols rather than two surgical techniques. Much of the existing literature has focused on minimally invasive fixation, sinus tarsi approaches, extensile lateral fixation, or augmentation strategies [25, 26]. In contrast, the present comparison addresses a practical clinical question: whether a protocol consisting of closed reduction, percutaneous screw fixation, and earlier rehabilitation is associated with measurable advantages over cast immobilization in fractures that are still frequently considered suitable for nonoperative care. Although proximal kinetic-chain outcomes were not assessed, previous work has suggested that calcaneal fractures may have broader functional consequences beyond the hindfoot alone [27]. This further supports the importance of optimizing both fracture management and rehabilitation strategy.
Overall, the present study suggests that closed reduction and percutaneous screw fixation with earlier rehabilitation may provide functional and radiographic advantages over cast immobilization in selected minimally displaced Sanders type II–III calcaneal fractures. However, because treatment allocation was center-based and rehabilitation protocols differed between groups, the results should be interpreted as protocol-associated findings. Future prospective studies are needed to clarify the relative contributions of reduction, stabilization, and early mobilization.
Limitations
This study has several limitations. First, the retrospective design introduces a risk of selection bias. Second, treatment allocation was center-based, with all percutaneous fixations performed at one center and all cast treatments at the other; therefore, treatment protocol and center were perfectly collinear, and center-related factors could not be adjusted for separately. Third, the protocols differed in both treatment method and rehabilitation timing, so the study cannot determine whether the observed functional differences were attributable to reduction and fixation, earlier mobilization, or their combination. Fourth, the study-specific definition of minimally displaced fractures may limit generalizability to other Sanders type II-III fracture populations. Fifth, clinical outcomes were assessed only at final follow-up, and early recovery, return to work, and range-of-motion trajectory could not be evaluated. Sixth, follow-up imaging was based on plain radiographs rather than routine computed tomography, limiting assessment of posterior facet congruity, coronal alignment, and early subtalar arthrosis. Finally, complete blinding was not feasible, FAAM Activities of Daily Living showed a ceiling effect, and AOFAS component-level analyses were exploratory and not adjusted for multiple comparisons.
Despite these limitations, the present study provides comparative mid-term data for a selected and relatively understudied subgroup of calcaneal fractures. Unlike much of the existing literature comparing minimally invasive fixation with open surgical approaches, this study compared two commonly used institutional treatment protocols: closed reduction with percutaneous screw fixation followed by earlier rehabilitation versus cast immobilization. The findings may help inform future prospective studies designed to separate the effects of reduction, fixation, immobilization duration, and rehabilitation strategy.
Conclusion
In selected patients with minimally displaced Sanders type II-III intra-articular calcaneal fractures without severe radiographic collapse, the institutional protocol comprising closed reduction, percutaneous screw fixation, and earlier range-of-motion exercises was associated with better mid-term functional outcomes and more favorable final radiographic parameters than cast immobilization. All fractures achieved union, and no wound-healing complications or surgical-site infections occurred after percutaneous fixation, although posterior implant-entry-site irritation requiring implant removal occurred in three patients. Given the retrospective design, center-based treatment allocation, and different rehabilitation protocols, these findings should be validated in prospective comparative studies.
Supplementary Information
Supplementary Material 1: Supplementary Table 1 Comparison of AOFAS Ankle-Hindfoot component scores between groups. Data are presented as median (interquartile range). Between-group comparisons were performed using the Mann–Whitney U test. Component-level AOFAS analyses were exploratory and were not adjusted for multiple comparisons. AOFAS, American Orthopaedic Foot & Ankle Society; IQR, interquartile range.
Acknowledgements
Not applicable.
Author contributions
All the authors contributed to the study’s conception and design. OS, BB, MU, RSE, AMO, and CK contributed to data collection. OS and BB performed the statistical analysis. OS drafted the manuscript. All authors critically revised the manuscript and approved the final version.
Funding
This research received no external funding.
Data availability
All datasets analyzed during this study are available from the corresponding author upon reasonable request.
Declarations
Ethics approval and consent to participate
The study protocol was approved by the Medical Research Ethics Committee of Izmir City Hospital (Approval No: 2026/244), which waived the requirement for written informed consent due to the retrospective nature of the study. All procedures involving human participants were performed in accordance with the ethical standards of the institutional and/or national research committee and with the 1964 Declaration of Helsinki and its later amendments.
Consent for publication
Not applicable.
Competing interests
The authors declare no competing interests.
Footnotes
Publisher’s note
Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.
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Associated Data
This section collects any data citations, data availability statements, or supplementary materials included in this article.
Supplementary Materials
Supplementary Material 1: Supplementary Table 1 Comparison of AOFAS Ankle-Hindfoot component scores between groups. Data are presented as median (interquartile range). Between-group comparisons were performed using the Mann–Whitney U test. Component-level AOFAS analyses were exploratory and were not adjusted for multiple comparisons. AOFAS, American Orthopaedic Foot & Ankle Society; IQR, interquartile range.
Data Availability Statement
All datasets analyzed during this study are available from the corresponding author upon reasonable request.