The role of early weight bearing in the aftertreatment of unilateral displaced intraarticular calcaneal fractures: a systematic review and pooled analysis

Abstract

Background

Displaced intraarticular calcaneal fractures (DIACFs) remain a complex challenge in orthopedic practice due to their complexity and the intricate nature of surgical interventions. While surgical techniques have evolved, postoperative rehabilitation is equally crucial for achieving optimal outcomes. This systematic review evaluates the effects of early weight bearing (EWB) in surgically treated patients with unilateral DIACFs on patient-reported outcomes, health-related quality of life, postoperative pain, differences in Böhler’s angle, and complication rates.

Methods

A systematic literature search was performed across PubMed, Embase, and Cochrane Library up to January 2025. Eligible studied included adults (≥ 18 years) who underwent surgery for unilateral DIACFs (Sanders type II–IV), implemented an EWB protocol, reported at least one patient-reported outcome, and were published from 2000 onward. Data extraction and quality assessment were conducted using the Newcastle–Ottawa Scale.

Results

From 1007 identified records, 20 studies (n = 1051 DIACFs) met the inclusion criteria. Pooled results showed a mean American Orthopedic Foot and Ankle Society (AOFAS) Score of 85.7, Maryland Foot Score of 91.1, and visual analog score of 1.9. The analysis revealed a decline of 0.4 degrees in Böhler’s angle from postoperative to last follow-up. The overall complication rate was 13.9%.

Conclusions

EWB protocols appear to be safe and beneficial in the postoperative management of DIACFs, yielding favorable outcomes without increased complication rates. These findings support the reconsideration of current conservative weight-bearing guidelines. Future research should focus on the development of standardized, evidence-based after-treatment guidelines.

Level of evidence

Level I.

Trial registration PROSPERO CRD42022280985

Supplementary Information

The online version contains supplementary material available at 10.1186/s10195-025-00863-w.

Introduction

The annual incidence of calcaneal fractures is approximately 11.5 per 100,000 patients and occurs 2.4 times more frequently in males than in females [1]. Operative treatment is often necessary, particularly in cases of displaced intraarticular calcaneal fractures (DIACFs), which are generally classified by the Sanders classification as type II–IV [2]. Even after successful operative treatment, prolonged aftertreatment is required, significantly impairing activities of daily living, quality of life, and socioeconomic factors [3, 4]. While anatomic surgical restoration may not completely prevent gait disturbances or persistent foot pain, it optimizes patient-reported outcomes [5].

To improve patient-reported outcomes, new surgical techniques have been developed over time [6]. Minimally invasive techniques such as percutaneous screw fixation (PSF) have been proposed for DIACFs to reduce wound complication rates and improve overall outcomes [7–9]. The L-shaped extensile lateral approach (ELA) remains the most widely used method for open reduction and internal fixation (ORIF) of DIACFs [10], although the sinus tarsi approach (STA) is gaining popularity [11].

According to the Arbeitsgemeinschaft für Osteosynthesefragen Principles of Fracture Management (‘AO guideline’, 2018), the current aftertreatment protocol for surgically treated trauma patients with DIACFs consists of non-weight bearing for up to 8–12 weeks, followed by partial weight bearing with a 25% increase in weight loading each week [12]. This has been the standard for decades, despite the well-documented positive effects of early weight bearing on fracture healing and maintenance of muscle and bone mass [13]. Furthermore, a recent radiological study demonstrated that early functional exercise and weight bearing can shape the subtalar joint and reduce the residual displacement of the articular surface, thereby improving the functional recovery of the affected foot [14]. A recent survey among orthopedic and trauma surgeons on the opinions on non-weight bearing guidelines for the after treatment of calcaneal fractures showed that 96% of the responding surgeons interpret the current protocol flexibly [15]. This raises the question of whether the current guidelines are overly cautious, influenced by fears of secondary fracture dislocation or mechanical construction failure.

Therefore, the aim of this systematic review and pooled analysis was to investigate the effectiveness of early weight bearing (EWB) in surgically treated patients with DIACFs on patient-reported outcomes, health-related quality of life, postoperative pain, differences in Böhler’s angle, and complications.

Methods

This systematic review was conducted and reported in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines [16, 17]. The review protocol was registered in the International Prospective Register of Systematic Reviews (PROSPERO) [18].

Data sources and search strategy

A comprehensive electronic literature search was conducted using the databases of PubMed, Embase, and the Cochrane Library up to January 2025. The search strategy included both free terms and Medical Subject Headings (MeSH) terms. Additionally, clinical queries were applied to retrieve targeted results pertinent to the diagnostic clinical question. No limits were imposed on the search itself. An overview of the database search strategies is presented in Table 1.

Table 1.

Database search strategies

Search concept	Free text terms	MeSH terms*
Postoperative period and care	Postoperative period, postoperative care, postoperative complications, weight-bearing, aftercare, rehabilitation, postoperative, post-operative, after-care, after treatment, weightbearing, loadbearing, load bearing	“Postoperative period”, “patient care”, “rehabilitation”, “weight-bearing”
Fracture type and location	Intraarticular fractur*, intraartricular fractur*, intraarticular heel bone fractur*, intraarticular calcane*, intraarticular calcis, intraarticular heel bone fractur*, intraarticular heel fractur*, intraarticular calcane*, intararticular calcis, Sanders type	“Fractures, intraarticular”, “calcaneus”, “heel”
Specific fracture terms	Calcaneus, heel, calcane*, calcis	“Calcaneus” [MeSH]
Surgical classification group	AO, Arbeitsgemeinschaft, Osteosynthesefragen	N/A (no MeSH term for AO classification)

^* MeSH terms were used when available and appropriate. All searches combined both MeSH and free-text terms where applicable

Two authors (C.V. and M.D.) supplemented the electronic database search by manually reviewing the reference lists of all selected articles to identify potentially relevant publications not previously identified.

Study selection

The search results were uploaded into Rayyan, a web and mobile app for systematic reviews, where duplicates were removed [19]. Articles were then screened by title and abstract for possible inclusion. Two authors (C.V. and M.D.) independently completed this selection process and determined which articles to include. Disagreements between reviewers were resolved through discussion with the senior authors (EH/MP).

Studies meeting the following criteria were eligible for inclusion: (1) randomized controlled trials and cohort studies (either prospective or retrospective); (2) target population consisting of patients > 18 years of age who underwent surgery for a unilateral DIACF; (3) description of at least one patient-reported outcome measure among American Orthopedic Foot and Ankle Society (AOFAS) Ankle-Hindfoot Score [20], Maryland Foot Score (MFS) [21], Short Form-12/36 (SF-12/36) [22], visual analog score (VAS) [23], and complications; (4) description of an EWB regime (defined as any regime allowing a faster start of weight bearing than the AO guidelines); and (5) full-text clinical studies in English, German, French, or Dutch published from 2000 onward.

Studies were excluded if they met any of the following criteria: (1) fewer than 10 participants; (2) inadequate description of outcome measures; (3) results from nonsurgically treated patients; (4) cohorts containing only Sanders IV fractures; (5) studies including bilateral fractures; and (6) editorials, opinion pieces, commentaries, letters, case studies, conference proceedings, systematic reviews, meta-analyses, narrative reviews, or animal studies.

Data extraction

Data extraction was performed independently by two authors (C.V. and M.D.) using a standardized extraction form. Extracted data included: (1) study characteristics (title, authors, year of publication, country, and continent); (2) methods (study design and number of participants); (3) patient characteristics (age and gender); (4) preoperative parameters [fracture type by Sanders classification, preoperative Böhler’s angle, and time-to-surgery (TTS)]; (5) perioperative parameters (type of surgery and operation time); (6) postoperative parameters (postoperative Böhler’s angle); (7) weight-bearing parameters (duration of non-weight bearing and time to full weight bearing); and (8) outcome measures (AOFAS, MFS, SF-12/36, all ranged 0–100; VAS, ranged 0–10; and complications). Any discrepancies in data extraction were resolved through discussion or consultation with senior authors (E.H./M.P.).

Methodological quality assessment

The methodological quality of the included studies was assessed using the Newcastle–Ottawa Scale (NOS) [24]. The NOS is a widely used tool in systematic reviews for assessing the quality and risk of bias in nonrandomized studies, particularly cohort and case–control studies. It provides a structured framework for evaluating the internal validity and methodological rigor of included studies, thereby aiding in the synthesis and interpretation of evidence. The scales uses a “star system” to judge articles in three broad perspectives: the selection of the study groups, the comparability of the groups, and the ascertainment of either the exposure or outcome of interest for case–control or cohort studies, respectively [25]. Studies were assigned in the following categories: “selection” and “outcome,” which lead to a star rating. The category “selection” assessed the studies on “representatives of exposed cohort” and “ascertainment of exposure.” The category outcome assessed the studies on “assessment of outcome,” “follow-up adequate for outcomes to occur,” and “adequate follow-up of cohort.” Several criteria, such as “selection of the nonexposed cohort,” were deemed inapplicable. Therefore, the maximum adjusted rating in this review was five stars. Two authors (C.V. and M.D.) independently assessed the studies and gave an overall judgement in terms of “low,” “high,” or “unclear.” In case of discrepancies, the reviewers reached a consensus during a discussion session.

A total of ten studies received a four-star rating; ten studies received a three-star rating. The detailed ratings are presented in Appendix 1.

Statistical analysis

All statistical analysis were performed using the meta package in R (Version 4.1.2; R Core Team 2023). A pooled meta-analysis was conducted to estimate the mean and 95% confidence intervals (95% CI) for the AOFAS Score, MFS, and VAS based on n = 19, n = 3, and n = 8 studies respectively. Pooled means were calculated using the inverse-variance method, incorporating the mean and standard deviation (SD) from individual studies.

Due to high heterogeneity across studies, a random-effects model was applied for subgroup analyses. Missing SD values were estimated using established methods, including the interquartile range (IQR) approach described by Wan et al. [26]. If no IQR was available, mean imputation (MI) was employed.

Heterogeneity was quantified using the I²-index, with sensitivity analyses conduced to explore sources of variability. Additional analyses stratified by age groups (Appendix 2a), continent of the study (Appendix 2b), Sanders classification (Appendix 2c), and study design (Appendix 2d) are detailed in Appendix 2.

Possible publication bias was assessed via funnel plot (Appendix 3) inspection and Egger’s test, which yielded no significant asymmetry (p-value = 0.900, α = 0.05) [27].

Results

The initial electronic database search identified 1007 potentially relevant articles, as shown in Table 1. Figure 1 illustrates the PRISMA flowchart of the selection process [16, 17]. Following the removal of duplicates, 862 articles were screened by title and abstract, with 612 excluded for irrelevance or failure to meet eligibility criteria. Full-text reviews of 250 articles led to the exclusion of 230 studies, resulting in the inclusion of 20 studies for analysis.

Fig. 1.

PRISMA flowchart of the article selection, n = number of studies

Table 2 presents the included studies, which represented a total of 1051 patients with unilateral DIACFs, with a median age of 44 years and 79.2% male participants. The mean TTS was 7 days (range 15 days).The mean operation time was 93 min (range 82 min). Study designs included randomized controlled trials (n = 3), prospective cohort studies (n = 3), and retrospective studies or case series (n = 14). Surgical approaches included the extensile lateral approach (ELA, n = 13), sinus tarsi approach (STA, n = 11), and percutaneous screw fixation (PSF, n = 1) [8–11].

Table 2.

Baseline characteristics of the included studies and patients

Author, year published	Design*	Country	Included (n)	Mean age (years)	Male (%)	TTS (days)	Mean operation time (min)	Type of surgery
Basile, 2010 [28]	3	Italy	18	68.9	55.6	16.2	–	ELA
Hirschmüller, 2011 [29]	3	Germany	60	46.4	71.7	8.3	–	ELA
Kline, 2013 [30]	3	USA	112	43.4	83.0	13.3	145	ELA, STA
Abdelazeem, 2014 [31]	3	Egypt	33	35.0	75.8	9	90	STA
Chen, 2014 [32]	3	China	42	43.9	88.1	–	122	ELA
Kayali, 2014 [33]	3	Turkey	15	40.1	80.0	5.7	–	ELA
Cao, 2015 [34]	3	China	33	36.0	75.8	< 2	69	PSF
Feng, 2016 [35]	1	China	38†	40.7	84.2	4.3	64	STA†
Li, 2016 [7]	1	China	64	40.5	73.5	5.8	–	ELA, STA
Chen, 2017 [14]	2	China	60	39.4	83.3	7	63	§
Chu, 2017 [36]	3	China	30	41.0	87.5	1.3	74	ELA
Park, 2017 [37]	3	S-Korea	47	50.7	80.9	10.1	–	STA
Brand, 2019 [38]	2	Germany	56	51.0	80.4	–	109	ELA, STA
Zhan, 2019 [39]	2	China	29	40.0	82.8	5.6	79	STA
Bremer, 2020 [40]	3	Switzerland	109	44.0	73.4	7	–	ELA
Cho, 2021 [41]	3	S-Korea	25	55.8	88.0	3.3	–	STA
Park, 2021 [42]	1	S-Korea	64	49.6	89.1	4.3	98	ELA, STA
Sugimoto, 2021 [43]	3	Japan	64	59.3	65.6	–	–	ELA, STA
Park, 2022 [44]	3	S-Korea	48	49.3	83.3	–	87	ELA
Xie, 2022 [45]	3	China	45	50.0	82.2	8.3	120	ELA, STA

^* Design: 1 = randomized controlled trial (RCT), 2 = prospective studies, 3 = retrospective cohort studies/case series

^†Only data presented from patients treated with conventional surgical methods; § Conventional surgery, not further specified

ELA extended lateral approach, STA sinus tarsi approach, PSF percutaneous screw fixation

n number of subjects, TTS time to surgery, min minute

Table 3 presents the fracture characteristics by Sanders and the distribution in percentages. The mean preoperative Böhler’s angle was 6.2 degrees (range −1.5 to 17.3 degrees). Direct postoperatively, the mean Böhler’s angle was 26.1 degrees (range 19.4 to 32.9 degrees). At the last follow-up, the mean Böhler’s angle was 25.7 degrees (range 18.6 to 35.1 degrees). The mean follow-up was 22.6 months (range 6 to 49.2 months).

Table 3.

Fracture characteristics

Author, year published	Sanders type	Distribution Sanders type	Pre-op BA (degree)	Post-op BA (degree)	BA last FU (degree)	Mean FU (months)
Basile, 2010 [28]	II–III	39%/61%	–	–	35.1	–
Hirschmüller, 2011 [29]	II–III–IV	42%/35%/20%*	11	26	–	49.2
Kline, 2013 [30]	II–III	55%/45%	17.3	27.4	–	30.1
Abdelazeem, 2014 [31]	II–III	45%/55%	2.8	19.4	–	28.8
Chen, 2014 [32]	II–III–IV	27%/50%/17%	8.2	32.9	28.2	25.5
Kayali, 2014 [33]	III–IV	73%/27%	10.5	23	22.7	19
Cao, 2015 [34]	II–III	61%/39%	9	31	–	21
Feng, 2016 [35]	II–III	79%/21%	2.2	30.4	28.9	24
Li, 2016 [7]	II–III–IV	52%/34%/14%	1.2	28	24.2	12
Chen, 2017 [14]	II–III–IV	32%/33%/35%	5.1	32.2	–	–
Chu, 2017 [36]	II–III–IV	58%/38%/4%	16.8	28.5	–	22.4
Park, 2017 [37]	II–III	72%/28%	1.1	20.4	–	23.2
Brand, 2019 [38]	II–III	55%/45%	–	–	–	6
Zhan, 2019 [39]	II–III	45%/55%	−1.5	29.4	29.4	18
Bremer, 2020 [40]	II–III	52%/48%	–	–	–	34
Cho, 2021 [41]	III–IV	72%/28%	5.1	24.2	–	15.3
Park, 2021 [42]	II	–	2	21	–	12
Sugimoto, 2021 [43]	II–III	47%/53%	5.3	22.2	18.6	14.5
Park, 2022 [44]	II–III–IV	54%/42%/4%	–	24.1	22.5	30
Xie, 2022 [45]	II–III	36%/64%	3.3	24.3	22	–

^* incomplete preoperative data

Pre-op preoperative, BA Böhler’s angle, Post-op postoperative, FU follow-up

Aftertreatment regimes

A total of 20 studies described an after-treatment procedure that allowed shorter period of non-weight bearing than the current AO guideline permits (8 to 12 weeks non-weight bearing). In three studies, a comparison of two after-treatment procedures was made [14, 42, 44]. Only the results from patients that followed early weight-bearing protocols were included in this review. The detailed postoperative weight bearing regimes are shown in Table 4.

Table 4.

Weight bearing regimes

Author, year published	Weeks of non-weight bearing	Weeks to full weight bearing	EWB/RWB
Basile, 2010 [28]	3	12	EWB
Hirschmüller, 2011 [29]	2	12	EWB
Kline, 2013 [30]	6	10	EWB
Abdelazeem, 2014 [31]	6	10	EWB
Chen, 2014 [32]	2	0	EWB
Kayali, 2014 [33]	0	12	EWB
Cao, 2015 [34]	3	n/a	EWB
Feng, 2016 [35]	4	12	EWB
Li, 2016 [7]	5	12	EWB
Chen, 2017 [14]	3	12	EWB
	6	12	RWB
Chu, 2017 [36]	0	6	EWB
Park, 2017 [37]	6	8	EWB
Brand, 2019 [38]	0	12	EWB
Zhan, 2019 [39]	4	12	EWB
Bremer, 2020 [40]	4	12	EWB
Cho, 2021 [41]	4	9	EWB
Park, 2021 [42]	6	10	EWB
	8	12	RWB
Sugimoto, 2021 [43]	5	9	EWB
Park, 2022 [44]	5	8	EWB
	8	12	RWB
Xie, 2022 [45]	4	12	EWB

EWB early weight bearing, RWB restricted weight bearing, n/a not announced

Patient-reported outcomes

The patient-reported outcome, measured by the AOFAS Score, was described in 19 studies and 912 patients, and is shown in a forest plot in Fig. 2. The mean AOFAS Score was 85.7.

Fig. 2.

AOFAS Score. *Estimated mean SD (standard deviation), based on the range. † Estimated mean SD, based on mean group SD. n number of included subjects, SD standard deviation, CI confidence interval

A total of three studies, with 81 patients, described the MFS. The mean MFS was 91.1 and is shown in a forest plot in Fig. 3.

Fig. 3.

MFS. *Estimated mean SD, based on the range. n number of included subjects, SD standard deviation, CI confidence interval

In total, eight studies described the VAS in a total of 414 patients. The mean VAS was 1.9. The results are shown in a forest plot in Fig. 4.

Fig. 4.

VAS. *Estimated mean SD, based on the range. † Estimated mean SD, based on mean group SD. n number of included subjects, SD standard deviation, CI confidence interval

Complications

A total of four studies were excluded from this table as the complications were not separately presented for the different after-treatment protocols [14, 42, 44, 46]. One study did not report mentioned complications and was therefore excluded from this analysis [38]. This resulted in a total of 16 studies presenting complications.

The rate of reoperations due to failure of osteosynthesis ranged from 2.8% to 16.7%. The rate of wound necrosis (WN) ranged from 0% to 13.3%. The rate of superficial wound infections (SWI) ranged from 2.8% to 22.3%. The occurrence of deep wound infections (DWI) ranged from 1.6% to 17.8%. The secondary arthrodesis ranged from 2.8% to 3.3%. Removal of osteosynthesis was not included in the total complication rate as it is a standard procedure in several countries (e.g., China), which could lead to distorted results.

Persistent pain (range: 5.6% to 42.4%) and nerve entrapment (range: 3% to 5.3%) were not considered for the total complication rate, as varying scales at different measurement times were used.

Summarizing, the median total percentage of complications (WN, SWI, DWI, reoperations due to failure of osteosynthesis, and secondary arthrodesis) was 13.9%.

In Table 5, the complications are shown.

Table 5.

Complications

Author, year published	FoO	Wound necrosis	SWI	DWI	Secondary arthrodesis	Total	Perst. pain	Nerve entrapment
Basile, 2010 [28]	16.7%	5.6%	–	–	–	27.8%	5.6%	–
Hirschmüller, 2011 [29]	8.3%	–	16.7%	10%	3.3%	35%	–	–
Kline, 2013 [30]	–	–	22.3%	6.3%	–	28.6%	6.3%	–
Abdelazeem, 2014 [31]	–	–	3%	–	–	3%	42.4%	3%
Chen, 2014 [32]	7.1%	–	4.8%	–	–	11.9%	–	–
Kayali, 2014 [33]	–	13.3%	20%	6.7%	–	40%	6.7%	–
Cao, 2015 [34]	–	–	6.1%	–	–	6.1%	–	–
Feng, 2016 [35]	–	2.6%	7.9%	5.3%	–	15.8%	–	5.3%
Li, 2016 [7]	–	–	10.9%	7.8%	–	18.8%	–	–
Chu, 2017 [36]	–	–	4.2%	–	–	4.2%	–	–
Park, 2017 [37]	–	6.4%	–	–	–	6.4%	14.9%	–
Zhan, 2019 [39]	–	3.4%	–	–	–	3.4%	–	3.4%
Bremer, 2020 [40]	2.8%	–	2.8%	–	2.8%	5.5%	–	–
Cho, 2021 [41]	–	–	8%	–	–	8%	–	–
Sugimoto, 2021 [43]	–	6.3%	9.4%	1.6%	–	17.2%	–	–
Xie, 2022 [45]	–	–	8.9%	17.8%	–	26.7%	–	26.7%

FoO failure of osteosynthesis, SWI superficial wound infection, DWI deep wound infection, perst. pain persistent pain

Discussion

This systematic review and pooled analysis aimed to provide a comprehensive overview of existing literature concerning early weight-bearing protocols in DIACFs. The primary focus was to evaluate the impact of these protocols on patient-reported outcomes, complications, and radiographic parameters. The results showed mixed outcomes for patient-reported outcome measures: the AOFAS Score was 85.7, whereas the MFS was 91.1. Pain levels assessed by the VAS were 1.9. Subdivided into pre-, directly post-, and post-operative at last follow-up, Böhler’s angles were described. This study revealed that a low degree of collapse of the Böhler’s angle was shown in comparison to direct postoperatively to last follow-up, namely only 0.4 degree.

However, complication rates are hard to compare with other literature owing to variation in definitions; the mean total complication rate was 13.9%.

The AOFAS Score is the most used patient-reported outcome in calcaneal studies and studies of the foot; therefore, it was used to measure the impact of weight-bearing protocols on patient-reported outcome in patients with DIACFs [47, 48]. The pooled analysis demonstrated an AOFAS Score of 85.7, which is higher compared with recent literature in studies with patients who followed RWB after-treatment protocols (74.4–81.6) [49–51]. It suggests that EWB positively influences patient-reported outcomes, although there was a small difference in score. Hirschmüller et al. [29] described a significantly reduced AOFAS Score compared with the other studies, which can probably be attributed to the high number of Sanders type IV fractures (20%) in that study. A systematic review of de Boer et al. [52] on both unilateral and bilateral DIACFs subdivided weight bearing in surgically treated patients with DIACFs into three categories “very early,” “early,” “intermediate,” and “late,” instead of two in the current systematic review [52]. The AOFAS Score for the early group (n = 4 studies) in the study of de Boer et al. was slightly less compared with this study (82.4 versus 85.7).

The MFS is the second most frequently used score as it was only used in three of the studies, whereas the AOFAS Score was used in all of them; however, it is worth mentioning. The MFS is known as the second most cited outcome score for DIACFs and was also used to assess the patient-reported outcome in patients with DIACFs [47]. The pooled analysis revealed that patients who adhered to an EWB protocol reached higher scores (91.1) in comparison with current literature [53–55]. To our knowledge, there is no systematic review or pooled analysis that compares the MFS for RWB versus EWB protocols in surgically treated DIACFs.

Pain levels were assessed by describing the VAS. This pooled analysis revealed that the VAS was very low, namely 1.9. This aligns with the findings related to the AOFAS Score, highlighting that EWB protocols not only enhance function but also contribute to pain reduction. This can potentially be attributed to reduced ankle stiffness. Nevertheless, there was a large range in collection time of the VAS; therefore, the score should be interpreted with caution. No extra use of pain medication was described in the studies.

The Böhler’s angles were recorded preoperatively, postoperatively, and at the final follow-up. Notably, in two studies, the Böhler’s angle measured immediately after surgery was lower than at the final follow-up [56, 57]. This study identified a significant correlation between the preoperative Böhler’s angle and the injury severity in DIACFs; however, only the postoperative Böhler’s angle showed a significant correlation with functional recovery [57].

A large variability in the described Böhler’s angles from the included studies was noticed. However, the known intra- and inter-observer variability for measuring Böhler’s angles reached only a moderate (κ = 0.55) level of agreement in a comparative study; the intraobserver reliability reached a substantial (κ = 0.77) level of agreement [58]. A more recent study showed that the AO-integral classification of injuries (ICI) classification system has levels of reproducibility similar to the Sanders classification [59]. Therefore, it can be questioned if the big variation in Böhler’s angles can be attributed to this variability.

The main reason for delaying postoperative weight bearing on the affected limb is the fear of fracture collapse. This study found a low degree of Böhler’s angle collapse of only 0.4 degrees. Therefore, an intriguing finding emerged from the calculated Böhler’s angles subdivided by after-treatment group. This finding was not in line with the results of de Boer et al. [52] that found a decline in the “early” weight bearing group of 2.5 degrees.

Another important aspect of this study was the assessment of complications associated with early weight bearing in DIACFs. Common complications included wound complications, hardware-related issues, and the occurrence of secondary arthrodesis [60]. These results emphasize that in the current practice the complication rate remains similar irrespective of the weight-bearing protocol. However, as complications rates are difficult to compare owing to differences in definitions, there is a need for the standardization of measuring complications.

Strengths

This recent systematic review and pooled analysis encompasses a substantial body of evidence, incorporating findings from 20 articles, and, in total, 1051 unilateral DIACFs, making it the most extensive study to date on weight-bearing protocols in unilateral DIACFs. This inclusiveness enhances the study’s robustness and provides a comprehensive overview of existing literature on the subject.

The utilization of a pooled analysis allowed aggregation of data across multiple studies and offered a more statistically powerful and precise estimation of the overall effects of weight-bearing protocols. This method enhances the generalizability and reliability of the study’s conclusions, providing a more comprehensive understanding of the impact of weight bearing on DIACFs.

Additionally, this review assessed publication bias in two different ways: first, by visually inspecting the symmetry of the funnel plots, and second, by quantifying this score using the Egger test. Both techniques showed a low change of publication bias, indicating a low likelihood that the results could have been biased and that significant positive findings are more likely to be published.

Limitations

Despite the valuable insights provided by this study, certain limitations should be acknowledged.

First, heterogeneity among the included studies was substantial and may have introduced bias into the pooled estimates. Although subgroup and sensitivity analyses were conducted to identify potential sources of heterogeneity, the observed variation could not be fully explained. Additionally, the methodological quality of the included studies varied, potentially affecting the overall strength and reliability of the conclusions.

Health-related quality of life outcomes measured by the SF-36 and SF-12 were excluded due to inconsistent reporting. Only a few studies provided the necessary physical component summary (PCS) and mental component summary (MCS) scores separately [61].

It should be noted that the actual fracture loading was not measured, making it unclear whether patients adhered to the postoperative protocols. Furthermore, none of the studies described crossover between the protocols. Specifically, a study by Kalmet et al. confirmed this hypothesis, demonstrating no significant difference in loading between early and late weight bearing groups [62].

Follow-up duration varied widely between studies. This variability may influence outcome comparisons, particularly when assessing complications and long-term functional recovery. The results may have balanced out over time. A study with long-term follow-up of 20 years after surgery reported that 82% of the patients experienced a clinical “steady state” at 14 months postoperative [63]. Moreover, a study by Kalmet et al. showed a positive effect of early weight bearing in tibial plateau fractures in the first 6 months, after which functional outcomes leveled out [62].

Moreover, the classification and reporting of complications lacked standardization across studies. As a result, several complications, such as nerve entrapment and persistent pain, were excluded from the pooled complication rate due to inconsistent definitions and assessment timing.

Finally, as more studies become available, future systematic reviews and meta-analyses may benefit from stratifying results by Sanders classification to determine whether early weight bearing is equally effective across different fracture types.

Future perspective

The suitability of the AOFAS Score as the preferred questionnaire for further research is questionable. Although the AOFAS Ankle-Hindfoot Score is the most used questionnaire in DIACFs, it has not been proven to be adequately valid, reliable, and responsive [64, 65]. A recent systematic review argued that the AOFAS Score should no longer be used in new research [48]. This underscores the need for a new questionnaire that is valid, reliable, and responsive for use in foot and ankle surgery.

Furthermore, to our knowledge, there are no randomized controlled trials comparing the effectiveness and cost-effectiveness of EWB versus RWB. High-quality randomized controlled trials are needed to provide more robust standardized definitions, evidence, and guidance for clinical decision-making regarding weight-bearing protocols in DIACFs.

Conclusions

This systematic review and pooled analysis suggest that early weight-bearing protocols are associated with high patient-reported outcomes, reduced pain, and minimal Böhler’s angle collapse in surgically treated patients with DIACFs. Comparable complications rates between early weight-bearing and non-weight-bearing protocols were observed. However, these conclusions should be interpreted cautiously due to high heterogeneity.

The minimal improvement in clinical outcomes further supports the need for well-structured randomized controlled trials to determine the optimal weight-bearing protocol in surgically treated patients with DIACFs.

Abbreviations

DIACFs

Displaced intraarticular calcaneal fractures

EWB

Early weight bearing

AOFAS

American Orthopedic Foot and Ankle Society

VAS

Visual analog score

MFS

Maryland Foot Score

STA

Sinus tarsi approach

ELA

Extensile lateral approach

ORIF

Open reduction and internal fixation

PSF

Percutaneous screw fixation

PRISMA

Preferred Reporting Items for Systematic Reviews and Meta-analyses

PROSPERO

International Prospective Register of Systematic Reviews

NOS

Newcastle–Ottawa Scale

IQR

Interquartile range

MI

Mean imputation

SF-12/36

Short Form-12/36

AO

Arbeitsgemeinschaft für Osteosynthesefragen

RWB

Restricted weight bearing

MCS

Mental component summary

PCS

Physical component summary

Author contributions

All authors contributed to the study conception and design. Material preparation, data collection, and analysis were performed by Mitchell Driessen, Pishtiwan Kalmet, and Coen Verstappen. The first draft of the manuscript was written by Coen Verstappen and all authors commented on previous versions of the manuscript. All authors read and approved the final manuscript.

Funding

No funding applicable.

Availability of data and materials

All data supporting the findings of this study are available upon reasonable request from the corresponding author.

Declarations

Ethics approval and consent to participate

Not applicable.

Consent for publication

Not applicable.

Competing interests

The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.