Evaluating radiologic outcomes of surgical techniques used in foot valgus deformity of cerebral palsy patients: a systematic review and meta-analysis

Abstract

Background

Planovalgus is the most common deformity in children with cerebral palsy (CP). Numerous surgical interventions like Lateral Calcaneal Lengthening (LCL), Extra-articular Arthrodesis (EAA), Subtalar Arthroereisis (SA), Intra-articular Arthrodesis (IAA), and Talonavicular Arthrodesis (TNA) are available to address it. However, there is currently a lack of evidence defining the optimal surgical approach. This systematic review and meta-analysis aim to evaluate the radiological outcomes of these surgical techniques.

Method

Databases were searched to identify relevant studies using keywords related to planovalgus, cerebral palsy, and surgical interventions. After removing duplicates, screening by title and abstract was followed by full-text screening. Data from the included studies were then extracted. Finally, a meta-analysis was performed on the finalized data.

Results

The findings revealed that the LCL procedure resulted in significant increases in the calcaneal pitch and the Anterior Posterior talonavicular coverage angle (AP TNCA), while reducing the Lateral talocalcaneal angle (Lat TC), Anterior Posterior talus-first metatarsal angle (AP TM1), and lateral talus-first metatarsal angle (Lat TM1). Similarly, the EAA surgery also enhanced calcaneal pitch and reduced Lat TC, Anterior Posterior talocalcaneal angle (AP TC), AP TM1, and Lat TM1. The SA surgery improved calcaneal pitch but decreased AP TC, and both Lat TC and Lat TM1 were reduced after the IAA intervention, with a significant decrease in AP TC after TNA surgery.

Between-technique comparisons were most consistent for lateral talocalcaneal (Lat TC) improvement favoring EAA over LCL, whereas comparisons involving SA and TNA remained underpowered. We therefore grade the comparative evidence as moderate for EAA vs LCL on Lat TC and Lat TM1, and low-to-very low for SA/TNA-related contrasts due to few studies and high heterogeneity.

Conclusion

The study concludes that while different surgical approaches have specific advantages, no single technique is definitively the best. The majority of surgeries were conducted on children aged 11–12. More research is necessary to enhance the reliability and accuracy of these findings, guiding better clinical decision-making for treating planovalgus in CP patients.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12891-025-09373-6.

Introduction

Cerebral Palsy (CP), is defined: “as a group of disorders that affect an individual’s movement, posture, and balance”, according to the Centers for Disease Control and Prevention [1]. The location of brain injury determines the pattern of injury. CP’s neurological problems are permanent, but movement disorders may cause musculoskeletal deformities that can progress over a lifetime [2–4]. The prevalence of CP ranges from 1.5 to 3 per 1000 live births, with variation across countries’ geographical and economic statuses [5–7].

Slow motor development, abnormal muscle tone and unusual postures are clinical clues that help clinicians diagnose CP in early life [8]. Valgus deformity is the most common foot deformity in CP patients. This deformity also known as Hindfoot valgus, Ankle valgus, pes valgus and planovalgus, is caused by tightness in the ankle flexor plantar muscles group [9]. In the early years of life, this deformity is flexible and can be managed conservatively with orthosis, medical shoes, and exercises [10]. However, as time passes, an increasing Body Mass Index (BMI) and foot load may cause the deformity to progress [11]. When contractures decrease function, cause pain, or interfere with daily activities, surgical management is necessary [11]. The goals of treatment in CP patients are not to achieve normal movement or a cure, but to improve functionality, capabilities, and independence [8].

Many surgical techniques have been used to correct Pes planovalgus deformity in CP patients, including soft tissue techniques such as tendon lengthening, transfer, or release [10], medial displacement osteotomy of the calcaneus, subtalar extraarticular arthrodesis, lengthening of the lateral column, and triple arthrodesis [12–16]. Each of these methods has its own advantages and disadvantages, leading to controversies among surgeons when choosing the most appropriate method. In this systematic review and meta-analysis, we aim to evaluate the radiologic outcomes of various surgical techniques to assist surgeons in making better decisions.

Methods

The approach and methodologies employed for this review were aligned with the Centre for Reviews and Dissemination (CRD) Guidelines for Conducting Healthcare Reviews [17]. The reporting of this review follows the guidelines set out by the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA).

Protocol and registration

This systematic review is registered with the International Prospective Register of Systematic Reviews (PROSPERO) under the registration ID CRD42024522936.

Eligibility criteria

We included a variety of study designs, such as prospective, retrospective, and comparative studies—including randomized controlled trials (RCTs), case studies, cohort studies, and case–control studies—that provided original or primary data on one or more outcomes of interest. A preliminary scoping review revealed a significant scarcity of RCTs on this topic. Therefore, it was necessary to include non-randomized studies to ensure a comprehensive review.

We excluded duplicate articles, studies focusing on cost-effectiveness, and works that did not report primary data, such as review articles, editorials, discussions, commentaries, letters, and conference abstracts. Furthermore, studies were excluded if data regarding pediatric patients with CP were not distinctly separable from other participants, or if surgery was not the primary intervention, as these did not align with the review’s objectives [18].

Participants

The study included children with CP who exhibited pes planus. Studies were considered if the average age of participants was under 18. Children without CP, who were treated for foot deformities other than pes planus, were excluded from the study.

Intervention

The intervention involved surgical management for treating symptomatic pes planus when conservative approaches had failed. A scoping review identified several specific surgical procedures, as follows:

Lateral calcaneal lengthening (LCL) is a surgical technique aimed at balancing the medial and lateral columns of the foot. This is achieved by performing an osteotomy of the calcaneus bone about 1.5 cm proximal to the calcaneocuboid joint. In cases of flatfoot, the lateral column is typically shorter, and this procedure corrects the resulting forefoot abduction while helping to restore the medial longitudinal arch. [19] The procedure gained widespread recognition through the work of Mosca, who enhanced it by incorporating soft tissue procedures and a plantar closing-wedge osteotomy of the medial cuneiform [20].

Extra-articular arthrodesis (EAA), which is also also known as Grice Green subtalar arthrodesis or non-fusion subtalar arthrodesis, involves positioning a structural autograft, often taken from the fibula or anterior tibia, between the talus and calcaneus outside the joint [12].

Calcaneal sliding (CS) is a procedure in which the posterior portion of the calcaneus is displaced medially. This movement compensates for deformities, improving the alignment of the heel and ensuring normal weight-bearing mechanics [21].

Intra-articular arthrodesis (IAA), commonly known as subtalar arthrodesis, refers to the fusion of one or more joints in the hindfoot or midfoot, often carried out as a triple arthrodesis. This procedure commonly involves the fusion of the talonavicular, subtalar, and calcaneocuboid joints, aimed at stabilizing the foot and reducing pain [22].

Subtalar arthroereisis (SA) involves the placement of an implant within or near the sinus tarsi to prevent talonavicular impingement. The implant restricts excessive eversion of the talus and calcaneus, helping to maintain the subtalar joint in a neutral position, thereby preventing further deformity [23].

Talonavicular arthrodesis (TNA) is performed through a medial longitudinal incision, typically over the posterior tibial tendon. The incision extends from the naviculocuneiform joint proximally to a point just inferior to the medial malleolus [24].

Tendo-Achilles lengthening (TAL) is frequently done using a coronal Z-plasty technique. The goal during surgery is to achieve 10° of ankle dorsiflexion with the knee extended [25].

Double calcaneal osteotomy (DCO) is a combination of LCL and CS.

Finally, the calcaneo-cuboid-cuneiform “triple C” osteotomies (TCO) is a versatile surgical approach that allows for comprehensive correction of deformities across the forefoot, midfoot, and hindfoot. This is achieved through three osteotomies: a CS, an opening-wedge osteotomy of the cuboid, and a plantar flexion closing-wedge osteotomy of the medial cuneiform [16].

Given the distinct indications and biomechanics, these techniques can be grouped into four categories:

1. Joint fusions (arthrodeses): including IAA, TNA, and EAA.

2. Joint-sparing osteotomies: including LCL, CS, DCO, TCO.

3. Arthroereisis: SA.

4. Soft-tissue adjunct procedures (muscle–tendon lengthening): TAL. In addition to the technique-level syntheses, we prespecified a category-wise framework reflecting clinical mechanisms and indications, using above categories.

Information sources

In June 2023, we conducted a comprehensive search across several databases, including Embase, PubMed, Scopus, Web of Science, CENTRAL, and clinicaltrials.gov, to identify relevant studies. Our search also encompassed gray literature sources, such as OpenGrey, the Center for Research Libraries Online Catalog (CRL), and the Open Access Theses and Dissertations (OATD), to locate any pertinent unpublished research. In February 2024, we refreshed our database search using the same methodology to incorporate the latest studies. Additionally, we employed a ‘snowball’ technique by performing forward and backward citation tracking on Scopus for all studies included in this review. This approach helped us discover further eligible studies or reports. Lastly, we examined the references of related reviews found during our search to ensure no potential studies were overlooked [26].

Search

Our search strategy follows the guidelines set by the Preferred Reporting Items for Systematic Reviews and Meta-Analyses literature search extension (PRISMA-S) [27]. We did not apply any restrictions or filters during the search process. Free-text terms and keywords were selected based on the MeSH Browser [28] and analyzed using the PubMed PubReMiner tool for word frequency [29]. A comprehensive account of the search strategy can be found in Appendix A.

Study selection

Citations gathered from literature searches and reference list checks were imported into EndNote [30]. EndNote’s de-duplication feature was used to identify and remove any duplicate entries. Two reviewers, independently assessed the titles and abstracts of the initial 50 reports, achieving an inter-rater reliability of 0.86 using Cohen’s kappa, which signifies almost perfect agreement. They then independently screened the titles and abstracts of all retrieved records, consulting a third reviewer to resolve any conflicts. These two reviewers also reviewed the full-text studies independently for inclusion, with studies accepted only when both reviewers agreed they met the criteria. Disagreements at this stage were also resolved with input from third reviewer [31].

Data collection process

The same reviewers independently utilized a data extraction form for gathering information from the eligible studies. Afterward, the extracted data were compared, and any inconsistencies were addressed through discussion. If data were missing or ambiguous, we reached out to the study authors for clarification.

Extracted data included:

• Study identifiers and design: first author, study name, level of evidence, and dates and design

• Characteristics of participants (dataset): number of patients and feet, gender, mean age, underlying diagnosis, mean follow-up (months/years), ambulatory status (GMFCS level of disability), type of plegia

• Radiographic outcomes: calcaneal pitch (Calpitch), Lateral Talohorizontal angle (Lat TH), Anterior–posterior talus-first metatarsal angle (AP TM1), lateral talus-first metatarsal angle (Lat TM1), Lat and AP talonavicular coverage angle (TNCA), Lat and AP talocalcaneal angle (TC).

• Surgery details: type of surgery and complications

Gait analysis and pedobarographic outcomes were not tabulated or synthesized due to the heterogeneity of the reporting between the studies.

Risk of bias

The “Checklist for Case-Series Studies” is a recommended tool by critical assessment tools for use in JBI Systematic Reviews. It was independently employed by the reviewers to assess all included studies, providing a robust framework for evaluating bias. Considered the most widely used tool for assessing risk of bias in systematic reviews of case-series studies, it is deemed suitable for this purpose [32, 33]. The reviewers documented supporting information and justifications for each bias judgment—categorized as low, unclear, high, or not applicable—across various domains. Any discrepancies between reviewers were discussed and documented to reach a consensus.

Meta-analysis

Meta-analyses were performed using R version 4 [34], employing the ‘SCSmeta’ function [35]. The Hartung-Knapp adjustment was applied to the random effects model for the analysis. To assess heterogeneity, we used H statistics, Cochran’s Q test, Higgins and Thompson’s I² statistics, and the heterogeneity variance τ² statistics. The influence of heterogeneity on the meta-analysis was examined when the I² statistic indicated inconsistency among the studies [36]. Additionally, heterogeneity was visually assessed through study data plots using the “Baujat plot.” A forest plot was utilized to present the overall results of the meta-analysis. For the category-wise add-on, we pooled the technique-level meta-analytic estimates within each category using inverse-variance random-effects with Hartung–Knapp adjustments. We report τ² and I² alongside 95% CIs; given the small number of contributing units, inferences are interpreted cautiously.

Comparative synthesis and grading

For between-technique contrasts (e.g., LCL vs EAA), we compared pooled pre–post mean differences of the same radiologic angle across techniques. Evidence strength for each comparison was graded using transparent, a priori rules: High (k ≥ 10 per arm, total feet ≥ 300, I² ≤ 60% and no small-study bias); Moderate (k ≥ 5 or total feet ≥ 150, or I² 60–80%); Low (k ≤ 4 and/or I² > 80%); Very low (k ≤ 3, very high I², and/or signals of small-study bias). Publication bias was judged by Egger’s test when applicable. Grades reflect confidence in comparative signals, not absolute pre–post improvements.

Sensitivity analysis

To assess the robustness of our study, a sensitivity analysis was conducted across different modalities. To ensure the consistency of our findings, we performed several sensitivity analyses using the Leave-One-Out method, where each study was sequentially excluded from the meta-analysis one at a time [37].

Reporting bias assessment

To determine if publication bias could affect the mean reliability coefficients derived from various meta-analyses, we conducted Egger tests and used funnel plots combined with the trim-and-fill method.

Results

Study selection

Five hundred seventy-five studies were identified through databases and 189 records were found through a grey literature search. Additionally, 20 more reports were discovered by searching the references of included studies, bringing the total number of records identified through the search strategy to 784. After removing duplicates, 438 reports underwent Level 1 screening (screening by title/abstract). Subsequently, 136 reports were assessed during Level 2 screening (screening by full text). The main reasons for excluding articles at this stage were “no reporting of outcomes” and “no separation of outcomes for patients with CP from patients with different etiologies for pes planus”. Ultimately, 58 records were considered relevant for data extraction and were included in our meta-analysis (Fig. 1) [38–95].

Fig. 1.

A Prisma flow diagram for the systematic review detailing the database searches, the number of abstracts screened, and the full texts reviewed

Study characteristics

All included studies were conducted between 1990 and 2022. They were categorized into eight different surgical procedures: LCL, EAA, SA, IAA, TNA, TAL, CS, and soft tissue interventions. The included studies involved 2669 feet in 1855 patients across 58 records (LCL: 1037 feet, EAA: 469 feet, SA: 176 feet, IAA: 452 feet, TNA: 143 feet, TAL: 144 feet, CS: 200 feet, soft tissue injuries: 246 feet). The patients’ mean age ranged from 5.45 to 16 years old, and the mean follow-up duration of the studies ranged from 3.2 to 271.2 months. The studies included patients with a GMFCS level of I–V, encompassing both stiff and flexible flatfoot deformities. The most frequent interventions in studies were: LCL(25 studies), EAA(14 studies), IAA (9 studies), and SA (4 studies). Detailed characteristics of the included studies are discussed in Table 1. Table 2 and Fig. 2 explains the results of a meta-analysis conducted. Meta-analyses were conducted for interventions that had sufficient radiologic data (Appendix B) and finally, 18 forest plots were created. Appendix C represents “Baujot plots” for each meta-analysis that visualize “overall heterogeneity contribution” across “influence on pooled result”.

Table 1.

Study characteristics

Author	Year	Type of surgery	Surgery Category	Feet	M/F	Age years (range or SD)	Follow-up (Months) (range or SD)	Ambulant/non-ambulant	Reported complications
J. Hamel [38]	1994	Grice–Schede: extra-articular subtalar arthrodesis (bone block) + medial soft-tissue stabilization (AT tibialis split transfer; PT advancement; TN capsuloplasty); ± heel-cord/peroneal lengthening	Joint fusion (arthrodesis)	43	NR	8.4 (3.4–16.4)	80.4 (7.2–165.6)	NR	Complete bony ingrowth: 25/43 (58.1%); non-union (talar or calcaneal): 3/43 (7.0%) with graft functioning as arthrorisis; mechanical graft failure/resorption: 15/43 (34.9%)—54.2% in tetraparetic subgroup; reoperation: 2 patients (recurrence 1, overcorrection 1). No pain at follow-up reported
V. Ettl [39]	2009	Calcaneal (lateral column) lengthening (Mosca-modified Evans) with iliac crest or fibular autograft; temporary CC K-wire fixation	Joint-sparing osteotomy	28	12/7	8.6 (4–18)	51.6 (12–103.2)	14/5	Relapse/recurrence: 7/28 (25%)—2/19 ambulant (11%), 5/9 non-ambulant (56%); superficial infection: 1/28 (~ 3.6%); no CC subluxation, no nerve/vascular injury, no donor-site problems; all osteotomies healed ≈8 weeks
K. Noritake [40]	2005	Calcaneal (lateral column) lengthening à la Mosca with tricortical iliac crest autograft + Steinmann pins; peroneus brevis & longus lengthening (± gastrocnemius/Achilles procedures)	Joint-sparing osteotomy	27	10/6	10.8 (5.8–14.5)	38.4 (24–60)	11/5	Unsatisfactory clinical outcomes: recurrence 5 feet; hindfoot varus (overcorrection) 2 feet. Other surgical complications not explicitly reported
J. Rhodes [41]	2017	Calcaneal (Evans) lengthening with cadaveric allograft (isolated osteotomy; ± gastrocnemius recession or TAL as indicated)	Joint-sparing osteotomy	34	56%/44%	9.3	39.4 (25.1–53.7)	NR	Cast pressure ulcer 8/39.0%? → actually 8 cases = 20.5% of allograft feet; clinical recurrence 15/34 (38.5%); return to surgery 0; delayed union 0; nonunion 0; no infections
		Calcaneal (Evans) lengthening with bovine xenograft (isolated osteotomy; ± gastrocnemius recession or TAL as indicated)	Joint-sparing osteotomy	29	55%/45%		35.1 (21.2–49)	NR	Cast pressure ulcer 0; clinical recurrence 13/29 (39.4%); return to surgery 2/29 (6.9%); delayed union 2/29 (6.9%); nonunion 1/29 (3.4%); no infections
J. Wen [42]	2017	Subtalar arthroereisis using a Subtalar Joint Stabilizer (SJS) (nonfusion)	Arthroereisis	20	8/4	7.8 (5–12)	28.3 ± 7.9 (20–48)	12/0	Occasional pain: 1/20 feet (resolved after implant removal); no wound/vascular/nerve injuries reported
		Dennyson–Fulford subtalar arthrodesis (talocalcaneal fusion with iliac cancellous bone graft + screw)	Joint fusion (arthrodesis)	22	9/5	9.2 (6–15)	31.9 ± 10.7 (22–60)	14/0	Occasional pain: 1/22 feet (relieved after hardware removal); screw fracture: 1 foot (asymptomatic); no wound/vascular/nerve injuries reported
A. Saeed Aly [43]	2019	Double calcaneal osteotomy: lateral column lengthening (Evans) + medial slide calcaneal osteotomy (± GC lengthening, TP advancement, peroneal lengthening, Cotton osteotomy as needed)	Joint-sparing osteotomy	24	9/7	10.74 (6–16)	33.5 (24–48)	16/0	Undercorrection (mild heel valgus): 2/16 cases = 12.5%; heel ulcer: 1/16 = 6.25%; chronic heel pain: 1/16 = 6.25% (improved after heel screw removal)
PF costici [44]	2019	Double hindfoot arthrodesis: talonavicular fusion (medial shortening osteotomy) + calcaneocuboid lengthening arthrodesis (bone graft), fixed with screws or staples	Joint fusion (arthrodesis)	175	64/39	14.7 (12–20)	62.4 (12–112)	48/55	Any complication 15/175 feet (8.6%); infections 4/175 (2.3%); TN delayed union 6/175 (3.4%); hardware breakage 5/175 (2.9%); further surgery 8/175 (4.6%) (2 hardware removal, 4 debridement, 2 new arthrodesis); persistent pain 7/175 (4.0%)
F. Zeifang [45]	2006	Evans calcaneal (lateral column) lengthening with tricortical iliac crest autograft and temporary K-wire fixation; frequent adjunct soft-tissue procedures (Strayer gastroc lengthening, peroneus lengthening; occasional medial capsular reefing)	Joint-sparing osteotomy	46	22/10	11 (4–22)	66 (36–108)	31/1	Recurrence: 7/46 feet (15.2%); overcorrection to varus: 4/46 (8.7%); graft collapse (mild loss of correction): 9/46 (19.6%); dorsal CC subluxation: 9/46 (19.6%)—symptomatic in 1 (→ CC fusion); donor-site hematomas: 10/32 patients (resolved without surgery); nonunion of calcaneus: 0; reoperations noted: triple arthrodesis in 2 feet
J. A. Barrasso [46]	1984	Grice extra-articular subtalar arthrodesis	Joint fusion (arthrodesis)	40	17/9	10.5 (3.5–14.9)	30 (16–53)	17/9	Immediate: superficial skin necrosis under cast (1 feet). Long-term: ankle valgus 14 feet; compensatory hindfoot varus 12 feet; hallux valgus in 3 patients (6 feet); graft resorption 7 feet; fibular pseudarthrosis with distal tibiofibular synostosis (1 feet)
H. Ki Yoon [47]	2010	Extra-articular subtalar arthrodesis (modified Dennyson–Fulford; cannulated screw + iliac cancellous graft)	Joint fusion (arthrodesis)	50	21/9	9 (5–18)	37 (26–49)	30/0	Heel sores 3; marginal wound necrosis 2 (resolved with local care); symptomatic proximal screw migration 2 (pain resolved after screw removal); no infections, no screw fractures, no pseudarthrosis
Ki Hyuk Sung [48]	2013	Calcaneal (lateral column) lengthening (Evans-type) with trapezoidal iliac crest allograft; peroneus brevis Z-lengthening; ± Strayer/TAL for equinus; no CC joint pinning/stabilization	Joint-sparing osteotomy	129	51/24	11.0 ± 5.2 (5.4–30.1)	37.2 ± 26.4 (12–100.8)	75	NR
AM. Aboelenein [49]	2018	Calcaneal (lateral column) lengthening à la Mosca (Evans modification) with iliac crest graft; PB Z-lengthening; TAL in all feet; temporary K-wire fixation	Joint-sparing osteotomy	22	5/10	11.5 (8.3–14.5)	31 (26–44)	15/0	Superficial infection 1/22 (4.5%); no CC subluxation; no donor-site/nerve injuries; 100% union
WJ Yoo [50]	2005	Calcaneal (lateral column) lengthening (Evans modification) with tricortical iliac crest bone graft; routine peroneus brevis Z-lengthening; ± Achilles/gastrocnemius lengthening; CC joint temporarily pinned if subluxated	Joint-sparing osteotomy	92	NR	9.2 (4.0–17.2)	62.4 (24.0–93.6)	39/17	Overcorrection to hindfoot varus 7/92 (7.6%); recurrence → repeat calcaneal lengthening 4/92 (4.3%); mild calcaneocuboid subluxation 3/92 (3.3%)
A. Narang [51]	2020	Calcaneal (lateral column) lengthening (Evans/Mosca) with tricortical iliac crest autograft, peroneus brevis Z-lengthening, temporary K-wire across CC joint	Joint-sparing osteotomy	17	NR	11.13 (8–18)	12	NR	Recurrence: 1 patient (~ 5.9% of patients); transient sural nerve paresthesia: 1 patient; no CC subluxation; no infections reported
S. Adams [52]	2009	Calcaneal (lateral column) lengthening with CC Steinmann-pin stabilization	Joint-sparing osteotomy	28	19/23	9.0 (6.3–13.9)	70 (41–102)	NR	CC subluxation 24/28 (85.7%); no OA at CC joint; no graft displacement; no nonunions; infections: 0 deep, 1 superficial in entire series
		Calcaneal (lateral column) lengthening without CC stabilization	Joint-sparing osteotomy	33		9.9 (6.8–14.2)	57 (48–172)	NR	CC subluxation 29/33 (87.9%); CC joint osteoarthritis 2/33 (grades 2–3; also OA in other tarsal joints); no graft displacement; no nonunions; infections: 0 deep, 1 superficial in entire series
NT Kim [53]	2021	Tendo-Achilles lengthening (TAL), coronal Z-plasty	Other (soft-tissue lengthening)	150	59/38	10.0 ± 5.9 (5.1–35.7)	32.4 (6–126)	NR	NR
HM. Elbarbary [54]	2020	Subtalar arthroereisis with percutaneous 6.5-mm cancellous screw + 13-mm washer across sinus tarsi; Achilles tendon lengthening in all; ± peroneal lengthening; ± multilevel soft-tissue releases	Arthroereisis	46	16/7	8.6 (6–12)	36.7 (24–40)	23/0	Wound infection: 1 case → debridement + hardware removal at 4 mo; no other intra/post-op complications (≈1/46 feet = 2.2% or 1/23 pts = 4.3%)
U. Lashkouski [55]	2019	Rotational reinsertion of the lateral layers of the Achilles tendon	Other (soft-tissue tendon procedure)	37	15/7	11.8 ± 2.7 (9.1–14.5)	12	22/0	NR
M. Kadhim [56]	2014	Subtalar fusion	Joint fusion (arthrodesis)	15	11/10	12.6 ± 2.5 (7.3–16.7)	24 ± 9.6 (12–47)	21/0	NR
		Lateral calcaneal lengthening	Joint-sparing osteotomy	19					NR
S. Bourelle [57]	2003	Grice extra-articular subtalar arthrodesis (fibular graft; K-wire stabilization in 10 feet; frequent concomitant TAL)	Joint fusion (arthrodesis)	26	9/8	5.45 (3.8–8.6)	243 (207- 268)	17/0	Immediate: superficial skin necrosis under cast 1 case. Long-term: ankle valgus 14/26 feet (often with compensatory hindfoot varus 12 feet); graft resorption 7/26; fibular donor-site pseudarthrosis with distal tibiofibular synostosis 1/26; no adjacent-joint arthritis, infections not reported
E. Nemejcova [58]	2016	Grice extra-articular subtalar arthrodesis (modified technique using tibial corticocancellous wedge; often combined with Young’s procedure)	Joint fusion (arthrodesis)	50	20/18	12 (7.2–17.7)	54	NR	No infections, no graft loosening/resorption; 1 patient developed Chopart (midfoot) malalignment at 3 years
DJ Oeffinger [59]	2000	Lateral column lengthening (Evans-type) with tricortical/bicortical iliac crest autograft and temporary K-wire fixation; adjuncts: TAL in 5 feet, peroneal fascial lengthening in 2 feet	Joint-sparing osteotomy	13	NR	13.6 ± 3.8	9.7 ± 4.5	All ambulant	NR
B Leidinger [60]	2011	Grice–Green extra-articular subtalar arthrodesis using autologous tibial cortical graft; ± Achilles/peroneal tendon lengthening; temporary K-wire stabilization in most feet	Joint fusion (arthrodesis)	51	20/15	7.8 ± 2.7 (3.9–14.4)	271.2 ± 55.2 (192–387.6)	19/16	Graft slippage: 1/51 (2%) → reoperation; overcorrection (varus): 4/51 (7.8%); undercorrection: 5/51 (9.8%); valgus recurrence: 2/51 (3.9%); donor-site tibial fracture: 2/51 (3.9%); graft pseudarthrosis: 2/51 (3.9%) (1 revised); graft resorption: 7/51 (13.7%) (did not worsen outcomes); degenerative changes (grade 1): 5/51 (9.8%)
CA Lou [61]	2017	Calcaneal (lateral column) lengthening (Evans modification) with tricortical iliac crest autograft; fixation by cannulated screw or K-wires	Joint-sparing osteotomy	30	14/6	11.9	30 (12–72)	19/1	NR
A Ramirez-Barragan [62]	2022	Talonavicular arthrodesis performed as part of single-event multilevel surgery (SEMLS)	Joint fusion (arthrodesis)	49	13/12	12 (11–15)	132 (120–150)	18/7	Screw protrusion 8% (4 feet) → screw removal after fusion; pseudarthrosis 14.2% (7 feet)—3 required salvage triple arthrodesis; no implant failure; no adjacent joint osteoarthritis at last follow-up
SA Rethlefsen [63]	2021	medial calcaneal sliding	Joint-sparing osteotomy	73	28/18	11.5 + 2.6	27.6 ± 24	46/0	NR
		lateral column lengthening	Joint-sparing osteotomy	46	13/13	10.5 ± 2.1	4.7 ± 3.4	26/0	NR
l. Molayem[64]	2009	Intra–sinus tarsi arthroereisis (Giannini screw)	Arthroereisis	14	3/5	11.7 (9.9–13.6)	72 (33.6–111.6)	8/0	3/14 (21.4%) implant dislocations → revision (Grice subtalar arthrodesis)
		Extra–sinus tarsi arthroereisis (Calcaneo-stop screw)	Arthroereisis	13	4/3	12.5 (9.3–14.5)	50.4 (26.4–75.6)	7/0	5/13 (38.5%) complications: 2 implant fractures, 3 dislocations → revision (Grice subtalar arthrodesis)
D.V Umnov [65]	2017	Corrective calcaneus osteotomy (author’s extra-articular “stepped” osteotomy; K-wire fixation; TN capsuloplasty; equinus addressed by Strayer or achilloplasty)	Joint-sparing osteotomy	103	NR	(3–17)	(6–96)	NR	Technical/tactical issues detailed: calcaneal fracture at sustentaculum base: 1 case; hypercorrection from excessive distal fragment shift: 1 case; incomplete equinus correction: 3 cases; misjudged deformity mobility: 2 cases. Overall outcomes: good 77/103 (75%), satisfactory 19/103 (18%), poor 7/103 (7%)
P. Osateerakun [66]	2022	Grice extra-articular subtalar fusion using ipsilateral tibial cortical autograft; TN K-wire in all cases (± additional K-wires)	Joint fusion (arthrodesis)	53	21/10	8.9 ± 1.8 (4.8–12.6)	64.8 ± 51.6 (12–220.8)	24/7	Non-union 14/53 (26%); hindfoot degenerative changes mostly mild (e.g., TN grade II–III 6/53); no tibial donor-site fractures; triple arthrodesis in 2 feet (1 patient)
J Jeray Kyle [67]	1998	extra-articular subtalar arthrodesis	Joint fusion (arthrodesis)	52	18/10	7.5 (5–12)	41 (27–78)
A. Andreacchio [68]	2000	Lateral column lengthening through the calcaneus (tricortical iliac crest graft; ± plate/screw fixation)	Joint-sparing osteotomy	16	NR	7.3 (6.2–17.8)	49.2 (27.6–61.2)	All Ambulant	Recurrence requiring revision: 4/16 (25%); secondary subtalar fusion: 1/16 (6.3%)
		Calcaneocuboid lengthening + fusion (resection, distraction, tricortical graft, plate/screws)	Joint fusion (arthrodesis)	7	NR	10.8 (9.1–16.6)			Nonunion at CC fusion: 3/7 (42.9%)—asymptomatic; overcorrection to varus: 2/7 (28.6%)
S.A. Aleksandrov [69]	2018	Subtalar arthroereisis with implant (isolated)	Arthroereisis	33 patients	NR	6–17 years	12–46	NR	4/33 pts (12.1%): 1 persistent pain → bilateral implant removal; 3 implant migrations (Kalix)
		Subtalar arthroereisis + anterior tibial tendon transposition & tenodesis (+ talonavicular capsular grafting; after equinus correction)	Arthroereisis + Soft-tissue procedure	31 patients	NR			NR	1/31 pts (3.2%): implant migration (Kalix); no Bioarch migrations reported
Karen M. Kruger [96]	2022	lateral column lengthening	Joint-sparing osteotomy	13	8/5	24.4 ± 5.7	183.6 ± 102	13/0 (GMFCS I = 1, II = 5, III = 7)	Reoperation 2/13 (15.4%); subtalar OA KL ≥ 2: 5/13 (38.5%) incl. KL4 severe 4/13 (30.8%); pain at follow-up: 46%
Byung Chae Cho [71]	2018	Calcaneal lengthening	Joint-sparing osteotomy	77	27/17	10.5 ± 4.0 (5.4–29.8)	61.2 ± 26.4	68/9	Calcaneocuboid joint subluxation: 5 cases; degenerative arthrosis: 2 cases; no nonunion or delayed union reported
A. Nather [72]	1984	Peroneus brevis intramuscular lengthening	Other (soft-tissue lengthening)	25	8/12	6.5 (2.1–14)	40.8 (13.2–111.6)	19/11	No specific complications reported for this subgroup; reoperations across the series included subtalar fusion (6 feet), tibialis posterior intramuscular lengthening (2 feet), and tendo-calcaneus lengthening (6 feet)
		Peroneus brevis tendon lengthening (Z-plasty)		2					Overcorrection → fixed inversion in 2/2 feet (100%); authors note this method risked making the tendon functionless by adhesions
		Peroneus brevis tenotomy		3					No overcorrection reported; outcomes mixed by hindfoot-valgus change (1 decreased, 1 unchanged, 1 increased)
Dawson Muir [73]	2005	Tibiotalocalcaneal arthrodesis (ankle + subtalar fusion; cannulated screw fixation)	Joint fusion (arthrodesis)	9	3/2	14 (11–17)	60 (52–69)	0/5	No early surgical complications; revision of tibiotalar arthrodesis 1/9; persistent pain-free fibrous ankylosis 1/9 with screw loosening & some subtalar motion; no growth-plate or hardware complications otherwise
Melih Guven [74]	2004	Grice subtalar extra-articular arthrodesis (fibular graft; no fixation)	Joint fusion (arthrodesis)	14	5/4	10.3 (6–12)	30 (6—81)	Ambulant: 9/9 patients (2 independent, 7 with aids)	Donor-site fibular nonunion 3/14 (21.4%); graft nonunion & displacement 1/14 (7.1%); no early skin necrosis/infection; no degenerative changes at follow-up
Camilo Andre´s Turriago [75]	2009	Talonavicular joint arthrodesis (fixation with Steinmann pin or cannulated screw)	Joint fusion (arthrodesis)	59	16/16	13.9 (9–20)	40 (18.3–66.7)	32/0	Pseudoarthrosis 7/59 (11.8%); revision surgery 7/59 (11.8%) (5 for pseudoarthrosis, 2 for insufficient correction); under-correction 2 feet, over-correction 1 foot; one case with severe postoperative pain due to malreduction
Luiz Antonio Ângelo da Silva [76]	2010	Pisani’s subtalar arthroereisis (screw + polyethylene dome; routine talonavicular capsuloplasty & tibialis posterior reinsertion; ± triceps surae/fibular tendon lengthening)	Arthroereisis	57	15/14	6 (3.75–8.6)	105 (30—168)	NR	Screw extrusion: 6/57 (≈11%)
Nickolas J. Nahm [77]	2020	Flatfoot reconstruction: calcaneal lengthening (Mosca) + medial cuneiform osteotomy (dorsal opening-wedge or plantarflexion closing-wedge); ± gastrocnemius/TA lengthening	Joint-sparing osteotomy	42	14/10	9.7 ± 3.4	14.4 (9.6–42)	24/0	NR
P.M Barros Fucs [78]	2012	Medial column arthrodesis (fusion of talonavicular, navicular–medial cuneiform, and medial cuneiform–first metatarsal joints) with plantar plate; ± talonavicular compression screw; occasional Achilles Z-lengthening	Joint fusion (arthrodesis)	35	13/8	16 (8–29)	58 (30–90)	14/7	Pseudarthrosis 13/35 feet (37%); reoperation 10/35 feet (29%) (5 for pseudarthrosis, 5 other reasons); 1 patient with persistent pain despite union; no infections or AVN
Ziad O. Abu-Faraj [79]	2001	Subtalar arthrodesis (fusion; Dennyson–Fulford method with metallic fixation)	Joint fusion (arthrodesis)	17	8/4	13.1 ± 2.6 (9–17.2)	12	12/0	No nonunions; no screw failures; no overcorrection to varus; radiographs showed solid fusion in anatomic position at follow-up
Benjamin J. Shore [80]	2013	Bilateral subtalar fusion using press-fit cortico-cancellous allograft + cannulated screw fixation (modified Dennyson–Fulford technique)	Joint fusion (arthrodesis)	46 patients	28/18	12.9 (7.8–18.4)	55 (30–90)	31/15	Fusion in 45/46 patients; 1 patient had bilateral stable fibrous unions; no wound complications or infections reported
Sergey S. Leonchuk [81]	2020	Grice extra-articular subtalar arthroereisis using fibular autograft with Kirschner-wire fixation (± posterior tibial tenodesis; ± gastrocnemius/Achilles lengthening)	Arthroereisis	58	20/9	6.3 (5–9)	42 (36–53)	29/0	K-wire/graft migration in 2 feet = 3.4% of feet (6.9% of patients): 1 required wire removal; 1 later required subtalar arthrodesis
Gad G. Guttmann [82]	1990	Extra-articular subtalar arthrodesis using a round iliac crest bone-plug dowel (Grice modification)	Joint fusion (arthrodesis)	26	9/6	5.2 (3–9)	81.6 (24–144)	15/0	Unsatisfactory 3/26 feet (11.6%) due to loss of correction/resorption/undersized plug; no infections (operative or donor site), no growth disturbance reported
George A. Mazis [83]	2012	Grice–Green extra-articular subtalar arthrodesis (fibular strut graft)	Joint fusion (arthrodesis)	16	7/4	9.7 (6.4–12.3)	43 (25–99)	NR	Nonunion: 3/16 (18.8%); graft resorption: 3/16 (18.8%)†; revision to triple arthrodesis: 2/16 (12.5%) due to loss of correction; no infections or skin necrosis; no graft fracture reported
Rana El-Hilaly [84]	2018	Calcaneo-cuboid-cuneiform (“triple-C”) osteotomies (MDCO + cuboid opening-wedge + medial cuneiform closing-wedge), often with adjunct soft-tissue procedures	Joint-sparing osteotomy	18	7/5	9.7 ± 3.46 (5.1–15.3)	3.9 (2.3–6.0)	12/0	NR
Ki Hyuk Sung [85]	2020	Calcaneal lengthening (Evans-type) with trapezoidal iliac crest allograft wedge; peroneus brevis Z-lengthening; ± tendo-Achilles lengthening; no CC pinning/stabilization	Joint-sparing osteotomy	68	23/15	11 ± 4 (5–19)	96 ± 36 (60–156)	NR	Radiographic OA (modified K-L ≥ 1): CC 31/68 (45.6%), TN 20/68 (29.4%); Bony spurs: CC 5/68 (7.4%), TN 8/68 (11.8%)
Amr H. Ahmed [86]	2020	Subtalar arthroereisis (calcaneostop screw)	Arthroereisis	28	10/6	9 ± 2.4 (5–12)	15.6 (12–22)	16/0	Transient sinus-tarsi pain 5/28 (17.9%); temporary supination 2/28 (7.1%); persistent sinus-tarsi pain 2/28 (7.1%); undercorrection (forefoot abduction component) 2/28 (7.1%); no wound infections reported
	2020	Lateral column lengthening (Evans osteotomy with trapezoid iliac crest graft + K-wires)	Joint-sparing osteotomy	29	9/10	9.1 ± 2.1 (5.5–12)		19/0	Transient pain 3/29 (10.3%) (1 donor site, 2 lateral foot); superficial wound infection 2/29 (6.9%); persistent lateral pain 1/29 (3.4%); undercorrection 4/29 (13.8%) (2 all components; 2 single-component)
Muayad Kadhim [87]	2012	Subtalar fusion (intra-articular fusion with allograft + screw fixation; often part of multilevel surgery)	Joint fusion (arthrodesis)	75	43/35	11.9 ± 2.9 (4.7–18.3)	60 ± 52.8 (12—184.8)	All Ambulent	Recurrence needing further surgery: 8/75 (10.7%). Hardware-related problems: 4/75 (5.3%). Infections: none reported
		Calcaneal lengthening (lateral column lengthening with allograft; often part of multilevel surgery)	Joint-sparing osteotomy	63					Recurrence needing further surgery: 4/63 (6.3%). Hardware-related problems: 6/63 (9.5%). Infections: none reported
Melih Güven [88]	2016	Modified Grice–Green extra-articular subtalar arthrodesis using a partial subperiosteal fibular graft (no internal fixation)	Joint fusion (arthrodesis)	15	5/6	10.7 (6–15)	24 (9–39)	9/2	Superficial skin necrosis under cast: 1/15 (6.7%); no infections; solid fusion in all feet; donor site: complete fibular regeneration in all; mild distal fibular valgus 2/15 (13.3%) without lateral malleolus migration (not counted as morbidity)
Marko Aleksić [89]	2020	Split posterior tibialis tendon transfer (SPOTT) — standard technique	Other (soft-tissue tendon transfer)	105	86/38	11 (6–15)	96 (72–132)	NR	No tendon ruptures or wound infections; revision (triple arthrodesis) 16/105 = 15.2%; poor outcome by Kling’s criteria 26/105 = 24.8%
		Split posterior tibialis tendon transfer (SPOTT) — modified technique (posterior half transferred to peroneus brevis + Z-plasty lengthening of remaining half)	Other (soft-tissue tendon transfer)	41		10 (7–14)	84 (72–132)	NR	No tendon ruptures or wound infections; revision (triple arthrodesis) 3/41 = 7.3%; poor outcome by Kling’s criteria 3/41 = 7.3%
Kai Rong [90]	2015	Intramuscular aponeurotic lengthening of gastrocnemius and/or soleus (Baumann procedure). Subgroups: 29 legs gastroc-only; 14 legs gastroc + soleus; + Hoke Achilles lengthening in 4 legs	Other (soft-tissue lengthening)	43	21/14	NR	39.4 (28–57)	NR	Recurrence of equinus 4/43 feet (9.3%) = 3/35 pts (8.6%); no overcorrection, no neurovascular injury, no wound-healing problems; 3 adult women reported prominent scar (cosmetic)
Pavel Akimau [91]	2014	Lateral column lengthening (calcaneal lengthening with tricortical iliac crest graft) with “à la carte” adjuncts (± medial displacement calcaneal osteotomy; ± medial cuneiform osteotomy; ± peroneus brevis → longus transfer; ± plantar fascia release; ± tibialis posterior advancement; ± Achilles lengthening)	Joint-sparing osteotomy	25	12/3	12.5 (5.58–16.25)	54 (32–75)	25/0	Transient sural neurapraxia 2 patients (resolved ≤ 6 mo); hardware-related symptoms → screw removal 1 patient; reoperation 3 patients/5 feet within 12 mo for under/over-correction (bilat. medial cuneiform osteotomy for residual supination; os calcis displacement osteotomy for residual valgus; bilat. lateral column shortening for overcorrection); no infections reported
Che-Nan Huang [92]	2013	Calcaneal lengthening (Evans-type) with iliac allograft + screw; Achilles/gastrocnemius lengthening in all	Joint-sparing osteotomy	19	6/5	11.1 ± 2.5 (6.85–15. 96)	31.3 ± 17.3 (13.0- 63.7)	11/0	Superficial wound infection: 2/19 (10.5%)—both resolved with oral antibiotics; osteotomy union: 100%
		Calcaneal lengthening + medial column stabilization (talonavicular stapling or arthrodesis when ≥ 11 y & irreducible) + Achilles/gastrocnemius lengthening	Joint-sparing osteotomy	18	2/8	10.98 ± 3.31 (4.85–14.60)	27.4 ± 7.3 (13.4- 36.0)	10/0	Staple penetration into TN joint: 8/18 (44.4%) → staples removed at 6–12 mo; TN arthrodesis nonunion: 0/7; osteotomy union: 100%; no infections reported in this group
Chakravarthy U. Dussa [93]	2017	Naviculectomy + midfoot arthrodesis (talo-cuneiform and calcaneocuboid fusion; K-wires/plates)	Joint fusion (arthrodesis)	44	NR	18.1 ± 7.5 (9–42)	60 ± 20.4	All Non-ambulant	Revisions: 3/44 (6.8%); pseudarthrosis (TC): 1/44 (2.3%); secondary wound closure: 4/44 (9.1%); recurrent distal tibial valgus: 2 feet in 1 patient; authors note hindfoot valgus under-correction ≈17%
M. Vlachou [94]	2004	Extra-articular subtalar arthrodesis with combined Batchelor–Grice (“Hong-Kong”) technique	Joint fusion (arthrodesis)	13	5/3	10.1 (5–14)	96 (24–180)	All ambulant	No infections or wound complications; solid fusion in all 13 feet; donor-site fibula united in all
Muayad Kadhim [95]	2013	Calcaneal (lateral column) lengthening with allograft, plate & screw fixation (through calcaneal neck or CC joint per stability)	Joint-sparing osteotomy	15	7/8 (by feet)	11 ± 3.2 (4.7–18.3)	130.8 ± 32.4 (75.6- 184.8)	All ambulant	Pain at long-term FU: 6/15 (40%); hardware prominence → removal: 3/15 (20%); additional foot surgery: 1/15 (6.7%); infections: 0; nonunion: 0
		Subtalar fusion (intra-articular, anterior facet) with 1–2 trans-articular screws + sinus tarsi allograft (posterior facet cartilage preserved)	Joint fusion (arthrodesis)	28	13/15 (by feet)				Pain at long-term FU: 1/28 (3.6%); hardware prominence → removal: 3/28 (10.7%); additional foot surgery: 6/28 (21.4%); infections: 0; nonunion: 0

NR Not Reported, CC Calcaneocuboid, GMFCS Gross Motor Function Classification System, OA Osteoarthritis, KL Kellgren-Lawrence scores

Table 2.

Meta-analysis of radiologic angles in various interventions

Type of surgery	Radiologic angle	Studies (n)	Feet (n)	Mean age (95% CI)	Mean pre-op (95% CI)	Mean post-op (95% CI)	Mean difference (95% CI)	p-value	I2 (%)	Eggers test p-value
IAA	Lat TC	4	195	10.96 (7.98–13.94)	52.92 (47.43–58.42)	34.75 (26.07–43.43)	−18.22 (−25.86,−10.6)	0.005	93.5	0.696
	Lat TM1	3	131	11.34 (6.61–16.08)	27.52 (9.16–45.88)	8.32 (−5.48–22.14)	−19.13 (−25.56,−12.7)	0.006	71.3	0.844
EAA	CalPitch	5	182	9.81 (7.82–11.81)	9.36 (7.69–11.03)	14.05 (9.78–18.32)	4.59 (1.84–7.32)	0.01	67.2	0.049*
	AP TC	6	174	8.97 (7.00–10.95)	33.93 (22.26–45.61)	19.86 (11.86–27.87)	−13.55 (−19.16,−7.94)	0.002	86.4	0.131
	Lat TC	12	406	8.98 (7.56–10.23)	48.42 (44.42–52.43)	33.09 (30.95–35.24)	−15.18 (−18.28,−12.1)	< 0.001	94.0	< 0.001*
	AP TM1	4	101	9.24 (7.36–11.12)	26.66 (17.11–36.20)	9.97 (0.32–19.62)	−16.60 (−18.38,−14.8)	< 0.001	0	0.648
	Lat TM1	4	101	9.18 (7.52–10.86)	21.71 (18.67–24.72)	3.38 (−0.89,7.65)	−18.16 (−24.16,−12.2)	0.002	46.4	0.451
TNA	AP TC	3	143	13.84 (8.94–18.73)	41.07 (33.34–48.82)	24.25 (14.60–33.90)	−16.92 (−26.68,−7.17)	0.0175	88.6	0.789
LCL	AP TC	4	168	10.26 (8.02–12.50)	30.02 (21.77–38.28)	21.60 (13.22–29.97)	−8.54 (−17.55, 0.46)	0.057	84.1	0.533
	CalPitch	16	741	10.58 (9.99–11.17)	4.69 (2.53–6.85)	12.25 (9.32–15.18)	7.59 (4.37–10.81)	< 0.001	96.4	0.599
	Lat TC	10	532	10.26 (9.36–11.16)	40.03 (34.71–45.36)	32.81 (26.33–39.28)	−7.19 (−10.52, −3.86)	< 0.001	81.8	0.385
	TH	5	135	11.06 (9.43–12.69)	37.94 (28.92- 46.96)	27.17 (21.53–32.83)	−11.02 (−17.28,−4.77)	0.006	75.5	0.915
	AP TM1	11	560	10.47 (9.67–11.27)	19.52 (12.05–26.99)	5.39 (0.27–10.5)	−14.18 (−19.58,−8.78)	< 0.001	91.8	0.195
	Lat TM1	17	764	10.45 (9.81–11.08)	25.01 (21.36–28.66)	11.31 (8.60–14.01)	−14.07 (−16.57,−11.6)	< 0.001	76.0	0.025*
	AP TNCA	7	224	10.24 (9.18–11.31)	11.35 (5.38–17.33)	27.37 (18.93–35.81)	16.25 (9.61–22.88)	< 0.001	84.2	0.221
SA	CalPitch	4	176	7.05 (3.00–11.11)	6.35 (2.52–10.19)	14.07 (6.49–21.66)	7.72 (2.71–12.72)	0.016	97.9	0.82
	Lat TC	4	176	7.05 (3.00–11.11)	49.71 (35.34–64.08)	30.05 (15.98–44.11)	−19.66 (−47.57,8.25)	0.111	99.9	0.813
	AP TC	4	176	7.05 (3.00–11.11)	33.37 (19.71–47.03)	19.18 (2.62–35.74)	−14.19 (−21.22,−7.16)	0.007	96.4	0.886

LCL Lateral calcaneal lengthening, EAA Extra-articular arthrodesis, SA Subtalar Arthroereisis, IAA Intra-articular arthrodesis, TNA Talonavicular Arthrodesis, AP TC Anterior Posterior talocalcaneal angle, CalPitch Calcaneal Pitch, Lat TC Lateral talocalcaneal angle, TH Talohorizontal angle, AP TM1 Anterior Posterior talus-first metatarsal angle, Lat TM1 Lateral talus-first metatarsal angle, AP TNCA Anterior Posterior talonavicular coverage angle

*: statistically significant (p < 0.05)

Fig. 2.

Schematic representation of the mean difference (95% CI) for each angle in various interventions

Lateral calcaneal lengthening

A review of 24 studies examined radiologic outcomes in CP patients with valgus deformity who underwent LCL [39–41, 43, 45, 48–52, 56, 59, 61, 63, 68, 70, 71, 77, 85–87, 91, 92, 95]. A quantitative analysis incorporating data from 16 studies with 1482 feet highlighted a significant post-operative increase in Calpitch compared to pre-operative measures (mean difference (MD) = 7.59, p < 0.001). (Fig. 3A). Additionally, 17 studies involving 1528 feet reported a notable post-surgical decrease in the Lat TM1 angle (MD = −14.07, p < 0.001). Eleven articles focused on the AP TM1 angle across 1120 feet and found a significant reduction in post-operative values (MD = −14.18, p < 0.001). Furthermore, 10 articles evaluated changes in the Lat TC angle for 1064 feet before and after LCL surgery, indicating a substantial decrease post-operation (MD = −7.19, p-value < 0.001). Additional changes in other radiologic parameters are detailed in Table 2 of the study.

Fig. 3.

Forest plot of A) calcaneal pitch angle after lateral calcaneal lengthening intervention B) Lateral talocalcaneal angle after Extra-articular arthrodesis surgery

Extra-articular arthrodesis

Fourteen studies examined radiologic outcomes in 469 feet with valgus deformity treated with EAA [38, 42, 46, 47, 57, 58, 60, 66, 67, 74, 82, 83, 88, 94]. Of these, 12 studies analyzed Lat TC, six assessed AP TC, five reported calpitch, and four evaluated AP TM1 and Lat TM1, involving 812, 348, 364, and 202 patients, respectively. The data revealed significant reductions in Lat TC post-surgery (MD = −15.18, p < 0.001, Fig. 3B) and AP TC (MD = 13.55, p = 0.002). Calpitch increased significantly post-surgery (MD = 4.79, p = 0.01). Post-operative reductions were noted in AP and Lat TM1 values (MD = −16.6, p = 0.001; MD = −18.16, p = 0.002, respectively). A meta-analysis of other radiologic measures was not feasible due to insufficient studies.

Subtalar arthroereisis

Four studies examined the effects of SA on individuals with valgus deformity CP, evaluating calpitch, AP TC, and Lat TC in 352 feet [69, 76, 81, 86]. After surgery, there was a significant increase in calpitch (MD = 7.72, p = 0.016) and a significant decrease in AP TC angle (MD = −14.19, p = 0.007). However, the decrease in Lat TC (MD = −19.66) was not statistically significant (p = 0.111).

Intra-articular arthrodesis

Nine studies reported on radiologic outcomes for patients with valgus deformity CP who underwent IAA. [42, 44, 46, 54, 56, 79, 80, 87, 95]. Four studies covering 390 feet analyzed Lat TC, and three studies with 262 feet examined Lat TM1 values. The meta-analysis showed a significant decrease in both angles. (MD = −18.22, p = 0.005; MD = −19.13, p = 0.006, respectively).

Talonavicular arthrodesis

Three studies investigated the radiologic outcomes of TNA in patients with valgus deformity CP, with a quantitative analysis focusing on AP TC[62, 75, 78]. A significant reduction in post-operative AP TC values was observed compared to pre-surgical data (MD = −16.92, p = 0.0175). Further analysis was limited due to insufficient data.

Risk of bias

Appendix D shows the risk of bias and concerns regarding applicability for each domain across the included studies. There were 34 studies with low risk of bias, 23 studies with moderate risk of bias, and one study with high risk of bias was identified.

Publication bias

To assess potential publication bias in the meta-analyses, Egger tests and contour-enhanced funnel plots using the trim-and-fill method were employed. The Egger’s test indicated publication bias in some of the meta-analyses (P < 0.05), as detailed in Table 2. Funnel plots and the trim-and-fill method were used to visualize and adjust for missing values, with results provided in Table 3. Appendix E includes the funnel plots. If the trim-and-fill method did not impute values, publication bias was unlikely; however, it indicated bias in our studies, as shown in Fig. 4.

Table 3.

Trim&fill test results of the radiologic outcomes in various interventions

Type of surgery	Radiologic angle	Studies (n)	Studies added (n)	fee t (n)	Mean difference (95% CI)	p-value	I2 (%)
IAA	Lat TC	4	0	195	−18.22 (−25.86,−10.6)	0.005	93.5
	Lat TM1	3	0	131	−19.13 (−25.56,−12.7)	0.006	71.3
EAA	CalPitch	5	0	192	4.59 (1.84–7.32)	0.01	67.2
	AP TC	8	2	214	−10.55 (−17.01,−4.09)	0.006	89.4
	Lat TC	19	7	604	−21.84 (−26.69, −16.99)	< 0.001	95.5
	AP TM1	5	1	116	−16.83 (−18.27, −15.39)	< 0.001	0
	Lat TM1	4	0	101	−18.16 (−24.16,−12.2)	0.002	46.4
TNA	AP TC	3	0	143	−16.92 (−26.68,−7.17)	0.0175	88.6
LCL	AP TC	5	1	198	−10.73 (−19.52, −1.94)	0.028	88.2
	CalPitch	24	7	1053	10.79 (7.72–13.86)	< 0.001	96.8
	Lat TC	14	3	652	−8.75 (−11.93, −5.56)	< 0.001	83.7
	TH	6	0	135	−11.02 (−17.28,−4.77)	0.006	75.5
	AP TM1	11	0	560	−14.18 (−19.58,−8.78)	< 0.001	91.8
	Lat TM1	24	5	858	−16.41 (−19.45,−13.38)	< 0.001	82.9
	AP TNCA	11	2	247	18.81 (12.04–25.58)	< 0.001	84.5
SA	CalPitch	4	0	176	7.72 (2.71–12.72)	0.016	97.9
	Lat TC	4	0	176	−19.66 (−47.57,8.25)	0.111	99.9
	AP TC	4	0	176	−14.19 (−21.22,−7.16)	0.007	96.4

LCL Lateral calcaneal lengthening, EAA Extra-articular arthrodesis, SA Subtalar Arthroereisis, IAA Intra-articular arthrodesis, TNA Talonavicular Arthrodesis, AP TC Anterior Posterior talocalcaneal angle, CalPitch Calcaneal Pitch, Lat TC Lateral talocalcaneal angle, TH Talohorizontal angle, AP TM1 Anterior Posterior talus-first metatarsal angle, Lat TM1 Lateral talus-first metatarsal angle, AP TNCA Anterior Posterior talonavicular coverage angle

Fig. 4.

Funnel plot of A calcaneal pitch angle after lateral calcaneal lengthening intervention B Lateral talocalcaneal angle after Extra-articular arthrodesis surgery

Sensitivity analysis

Several sensitivity analyses were performed to test the robustness of the observed prevalence. The results of eliminating any single study at a time from each of the meta-analyses (Leave-One-Out meta-analysis results) are depicted in Fig. 5 and appendix F.

Fig. 5.

Sensitivity analysis of A calcaneal pitch angle after lateral calcaneal lengthening intervention B Lateral talocalcaneal angle after Extra-articular arthrodesis surgery

Sensitivity analyses excluding studies that combined adjunct procedures (such as TAL, LCL, or TAL) yielded comparable direction and magnitude of effect sizes across major radiographic parameters, indicating minimal confounding from multi-procedure cases.

Subgroup analysis

The study results for each intervention were divided into three subgroups based on follow-up duration: short-term (less than two years), midterm (2–5 years), and long-term (more than 5 years). These subgroup results are detailed in Table 4, Fig. 6, and Appendix G. Subgroup analyses by follow-up duration did not reveal consistent time-related patterns in the available data. However, several strata were small (e.g., some EAA Lat TC strata included only ~ 4 studies), limiting statistical power. Accordingly, non-significant findings should not be interpreted as equivalence across time; rather, they reflect imprecision and the exploratory nature of these comparisons.

Table 4.

Meta-analysis of radiologic angles in various interventions and follow-ups

Type of surgery	Radiologic angle	Follow up	Studies (n)	Feet (n)	MD	95% CI	I2 (%)	Subgroup p-value
LCL	CalPitch	Short term	6	207	5.95	4.12; 7.77	8.20	0.50
		Midterm	5	166	11.44	2.48; 9.08	82.0
		Long term	6	368	5.78	2.48; 9.08	98.5
	Lat TC	Midterm	4	152	−8.15	−17.25; 0.95	89.0	0.71
		Long term	5	351	−6.81	−10.18; −3.44	72.0
	AP TM1	Short term	5	190	−13.08	−24.90; −1.26	94.0	0.51
		Long term	4	243	−17.34	−22.21; −12.46	75.0
	Lat TM1	Short term	6	207	−12.53	−18.86; −6.19	82.8	0.40
		Midterm	7	189	−13.42	−19.32; −7.52	70.0
		Long term	6	368	−15.90	−19.35; −12.45	72.8
EAA	Lat TC	Mid term	6	116	−14.39	−19.58; −9.20	82.0	0.42
		Long term	4	222	−13.85	−19.16; −8.55	55.0

LCL Lateral calcaneal lengthening, EAA Extra-articular arthrodesis, CalPitch Calcaneal Pitch, Lat TC Lateral talocalcaneal angle, AP TM1 Anterior Posterior talus-first metatarsal angle, Lat TM1 Lateral talus-first metatarsal angle, MD mean difference

Fig. 6.

Subgroup analysis of A calcaneal pitch angle after lateral calcaneal lengthening intervention B Lateral talus-first metatarsal angle after Lateral Calcaneal Lengthening surgery

Category-wise analysis

Across the three prespecified procedure groups (joint fusions [IAA, TNA, EAA], joint-sparing osteotomy [LCL], and arthroereisis [SA]) the category-wise random-effects pooling showed within-category mean differences (Table 5, Fig. 9). In joint fusions, pooled effects indicated AP TC − 14.54 (95% CI − 17.06 to − 12.02; 13 studies; I2 = 96.9%), AP TM1 − 16.74 (95% CI − 19.49 to − 13.99; 4 studies; I2 = 0%), Lat TC − 16.22 (95% CI − 23.04 to − 9.40; 16 studies; I2 = 99.7%), and calcaneal pitch + 6.03 (95% CI 3.74 to 8.32; 9 studies; I2 = 97.7%). For joint-sparing osteotomy, category-level estimates favored improvement in AP TM1 − 14.18 (95% CI − 19.58 to − 8.78; 11 studies; I2 = 91.8%), Lat TM1 − 13.84 (95% CI − 16.26 to − 11.42; 17 to 19 studies; I2 = 87.7%), and Lat TC − 7.09 (95% CI − 9.68 to − 4.51; 11 studies; I2 = 88.9%), alongside increases in calcaneal pitch + 7.57 (95% CI 3.63 to 11.52; 17 studies; I2 = 98.2%) and AP TNCA + 16.25 (95% CI 9.61 to 22.88; I2 around 84%). For arthroereisis, improvements were most evident in AP TC − 14.19 (95% CI − 21.27 to − 7.16; 4 studies; I2 = 96.4%); Lat TC showed a directionally favorable but imprecise estimate − 19.66 (95% CI − 47.57 to 8.25; 4 studies; I2 = 99.9%), and calcaneal pitch increased by + 7.72 (95% CI 2.71 to 12.72; 4 studies; I2 = 97.9%). Egger’s tests were generally non-significant in Table 5, with a small-study signal for LCL Lat TM1.

Table 5.

Meta-analysis of radiologic angles in various categories

Category	Radiologic angle	Studies (n)	Feet (n)	Mean age (95% CI)	Mean pre-op (95% CI)	Mean post-op (95% CI)	Mean difference (95% CI)	p-value	I2 (%)	Eggers test p-value
Joint Fusion	AP TC	13	493	9.71 (7.99–11.43)	35.4 (31.16–39.63)	20.67 (16.99–24.34)	−14.54 (−17.06,−12.02)	< 0.001	96.9	0.466
	AP TM1	4	101	9.21 (7.81–10.62)	26.65 (16.74–36.56)	9.97 (1.11–18.83)	−16.74 (−19.49,−13.99)	< 0.001	0	0.494
	Lat TC	16	582	8.52 (7.46–9.58)	48.73 (44.52–52.94)	32.39 (29.35–35.42)	−16.22 (−23.04,−9.4)	< 0.001	99.7	0.555
	Lat TM1	4	101	9.19 (7.84–10.53)	21.71 (18.56–24.87)	3.37 (−1.15–7.89)	−18.23 (−23.48,−12.98)	0.002	63	0.29
	CalPitch	9	358	8.78 (7.14–10.41)	7.98 (5.96–10.0)	14.05 (10.69–17.41)	6.03 (3.74–8.32)	< 0.001	97.7	0.372
Joint-Sparing Osteotomy	AP TC	4	168	10.26 (8.02–12.50)	30.02 (21.77–38.28)	21.60 (13.22–29.97)	−8.54 (−17.55, 0.46)	0.057	84.1	0.533
	AP TM1	11	560	10.47 (9.67–11.27)	19.52 (12.05–26.99)	5.39 (0.27–10.5)	−14.18 (−19.58,−8.78)	< 0.001	91.8	0.195
	Lat TC	10	532	10.26 (9.36–11.16)	40.03 (34.71–45.36)	32.81 (26.33–39.28)	−7.19 (−10.52, −3.86)	< 0.001	81.8	0.385
	Lat TM1	17	764	10.45 (9.81–11.08)	25.01 (21.36–28.66)	11.31 (8.60–14.01)	−14.07 (−16.57,−11.6)	< 0.001	76.0	0.025*
	CalPitch	16	741	10.58 (9.99–11.17)	4.69 (2.53–6.85)	12.25 (9.32–15.18)	7.59 (4.37–10.81)	< 0.001	96.4	0.599
	TH	5	135	11.06 (9.43–12.69)	37.94 (28.92- 46.96)	27.17 (21.53–32.83)	−11.02 (−17.28,−4.77)	0.006	75.5	0.915
	AP TNCA	7	224	10.24 (9.18–11.31)	11.35 (5.38–17.33)	27.37 (18.93–35.81)	16.25 (9.61–22.88)	< 0.001	84.2	0.221
Arthroereisis	AP TC	4	176	7.05 (3.00–11.11)	33.37 (19.71–47.03)	19.18 (2.62–35.74)	−14.19 (−21.22,−7.16)	0.007	96.4	0.886
	Lat TC	4	176	7.05 (3.00–11.11)	49.71 (35.34–64.08)	30.05 (15.98–44.11)	−19.66 (−47.57,8.25)	0.111	99.9	0.813
	CalPitch	4	176	7.05 (3.00–11.11)	6.35 (2.52–10.19)	14.07 (6.49–21.66)	7.72 (2.71–12.72)	0.016	97.9	0.82

AP TC Anterior Posterior talocalcaneal angle, CalPitch Calcaneal Pitch, Lat TC Lateral talocalcaneal angle, TH Talohorizontal angle, AP TM1 Anterior Posterior talus-first metatarsal angle, Lat TM1 Lateral talus-first metatarsal angle, AP TNCA Anterior Posterior talonavicular coverage angle

*: statistically significant (p < 0.05)

Fig. 9.

Schematic representation of the mean difference (95% CI) for each angle in various categories: (A) joint fusions; (B) joint-sparing osteotomy; (C) arthroereisis

Discussion

This study presents the first systematic review and meta-analysis of surgical treatments for pes planus valgus in children with CP, comprising 2938 operations from 58 research papers. In this study, we compared the extent of improvement achieved by various interventions across different radiologic parameters. Additionally, we analyzed the age distribution of patients who have undergone different surgical methods.

In the LCL intervention, the calpitch and AP TNCA significantly increased. Additionally, Lat TC, AP TM1, and Lat TM1 significantly decreased. In EAA surgery, calpitch was enhanced. The Lat TC, AP TC, AP TM1, and Lat TM1 were reduced. In SA surgery, calpitch increased, while AP TC decreased. Lat TC and Lat TM1 decreased after IAA intervention and AP TC decreased after TNA surgery, significantly.

The analysis in Fig. 7 indicates that there were no significant differences among LCL, EAA, and SA surgeries in enhancing calpitch. EAA and IAA showed better improvements in Lat TC compared to LCL, while Lat TM1 changes were similar across LCL, EAA, and IAA. Additionally, AP TC alterations did not significantly differ among LCL, EAA, SA, and IAA surgeries, and AP TM1 changes were comparable for LCL and EAA (Fig. 7). The ages of patients undergoing different surgeries did not significantly vary, ruling out age as a confounding factor in interpreting the results and surgical choices for treating valgus deformity (Table 2). However, based on comparative analysis showed in Table 6, comparative signals were most credible for EAA vs LCL on Lat TC and Lat TM1 (moderate-strength evidence driven by larger k and samples), whereas contrasts involving SA and TNA were consistently underpowered and highly heterogeneous. Accordingly, non-significant findings in these underpowered contrasts should not be interpreted as equivalence; rather, they reflect imprecision.

Fig. 7.

Mean difference and 95%CI of A Calcaneal pitch B Lateral Talocalcaneal angle C Lateral talus-first metatarsal angle D Anterior Posterior Talocalcaneal Angle E Anterior–Posterior talus-first metatarsal angle in various surgical modalities

Table 6.

Summary of comparative analysis strength

Comparison	Outcome	k (tech A/tech B)	Heterogeneity note	Small-study bias	Evidence strength
EAA vs LCL	Lat TC	12/10	High I2 in both arms (≈94%/82%)	none flagged	Moderate
EAA vs LCL	Lat TM1	4/17	I2≈46% (EAA)/76% (LCL)	Egger* sig. for LCL Lat TM1 (p = 0.025)	Moderate
LCL vs EAA vs SA	Calcaneal Pitch	16/5/4	High I2 across arms	none/limited	Low–Moderate
LCL/EAA/IAA/SA	AP TC	4/6/—/4	High I2 in several arms	mixed	Low
IAA vs LCL	Lat TC	4/10	I2≈93.5% (IAA)/81.8% (LCL)	—	Low–Moderate
Any vs TNA	AP TC	—/3	I2≈88.6%	—	Low/Very-low
Any vs SA	Lat TC/AP TC	—/4	I2≈99–100%	—	Very-low

LCL Lateral calcaneal lengthening, EAA Extra-articular arthrodesis, SA Subtalar Arthroereisis, IAA Intra-articular arthrodesis, TNA Talonavicular Arthrodesis, AP TC Anterior Posterior talocalcaneal angle, CalPitch Calcaneal Pitch, Lat TC Lateral talocalcaneal angle, TH Talohorizontal angle, AP TM1 Anterior Posterior talus-first metatarsal angle, Lat TM1 Lateral talus-first metatarsal angle, AP TNCA Anterior Posterior talonavicular coverage angle

*: statistically significant (p < 0.05)

Our subgroup analyses did not identify consistent trends across follow-up durations; however, many strata were small and heterogeneous, increasing the risk of type II error. Therefore, absence of statistical significance should not be misread as stability of outcomes over time. This is particularly relevant for fusion procedures (e.g., IAA), in which late adjacent-joint degeneration may emerge beyond typical follow-up windows. The observed heterogeneity (I² often > 90%) likely reflects variation in several unmeasured clinical parameters, including GMFCS levels, flexibility of deformity, and surgeon experience. Radiographic technique variability and differing thresholds for surgery selection may further amplify inconsistency. Explicit reporting of GMFCS stratification and deformity flexibility in future studies would improve comparability and strengthen meta-analytic precision.

To determine the most appropriate type of intervention, it is essential to first evaluate the severity of the patient’s deformity across different planes (Table 7). In the coronal plane, if significant improvement is desired, LCL may not be the optimal choice. Instead, SA and IAA interventions may be more effective. For mild deformities in the sagittal plane, the LCL technique can be utilized, and it is advisable to avoid heavy and complex interventions. Comparing these techniques in the axial plane requires more evidence, but current findings suggest that LCL and EAA produce similar results. Specifically, LCL and EAA outcomes are comparable in the sagittal and axial planes, although EAA is more commonly chosen for younger patients. Finally, while IAA offers the most enhancements across different planes, it is a complex and extensive surgery that may lead to the loss of some movements and muscle functions. Conversely, LCL achieves the least enhancements but comes with fewer side effects compared to other techniques.

Table 7.

Mean differences of various radiologic angles among different planes

	Sagittal plane		Coronal plane			Axial plane
	CalPitch	Lat TM1	TH	AP TC	Lat TC	AP TM1	TP TNCA
IAA	-	−19.13	-	-	−18.22	-	-
EAA	4.59	−18.16	-	−13.55	−15.18	−16.6	-
LCL	7.59	−14.07	11.02	8.54	7.19	−14.18	16.25
SA	7.72	-	-	−14.19	−19.66	-	-

LCL Lateral calcaneal lengthening, EAA Extra-articular arthrodesis, SA Subtalar Arthroereisis, IAA Intra-articular arthrodesis, AP TC Anterior Posterior talocalcaneal angle, CalPitch Calcaneal Pitch, Lat TC Lateral talocalcaneal angle, TH Talohorizontal angle, AP TM1 Anterior Posterior talus-first metatarsal angle, Lat TM1 Lateral talus-first metatarsal angle, AP TNCA Anterior Posterior talonavicular coverage angle

Figure 8 displays the total number of feet that have undergone surgery in each surgery type (from included studies) across different age groups (in years). The majority of surgeries were performed on children aged 11–12. Additionally, EAA is more popular among children under 9 years old, while TNA is more common in children above 13 years old.

Fig. 8.

The total number of feet that have undergone surgery in each surgery type (from included studies) across different age groups (in years)

There is a notable deficit of research on CS, IAA, SA, TNA, TAL, DCO, and TCO studies as shown in Table 1. When it comes to moderate-to-severe flatfoot malformations, there is insufficient evidence to accurately evaluate suitable choices for treatment. The majority of the individuals taken into these trials had flexible deformity with lower GMFCS values. It is important for analyses to differentiate between the management of stiff flatfoot in GMFCS levels IV and V and flexible flatfoot in GMFCS levels I–III due to the distinct nature of these deformities. Several articles categorized patients into levels I–IV or I–V, or classified them as “ambulant” or “non-ambulant,” which hindered subgroup comparisons due to insufficient information separation.

Our study also highlights the need for a standardized approach to monitor clinical outcomes. Although radiologic correction reflects structural alignment, its clinical significance lies in improved gait efficiency and patient function. Several included studies reported parallel improvements in gait parameters, walking speed, and energy expenditure following correction, suggesting that angular changes correspond to better load distribution and functional outcomes. However, standardized outcome tools such as the Gross Motor Function Measure (GMFM) or gait analysis were inconsistently reported, limiting quantitative synthesis. Future studies integrating radiographic and functional endpoints are essential to define clinically meaningful correction thresholds. While studies on LCL used either Mosca’s or Yoo’s clinical criteria, future efforts could merge and validate these criteria for comparing techniques and integrating exercise levels for functional analysis [20, 39, 40, 86, 92]. In the future, these criteria might be merged and verified to compare various techniques, potentially modified to include levels of exercise for functional analysis. The studies lacked patient-reported outcomes, which are crucial for evaluating the impact of medical interventions on an individual’s quality of life. For instance, pain alleviation following surgery is a crucial therapeutic outcome which was either not fully recorded or not consistent enough to analyze. Standardized techniques for assessing gait analysis, kinematics, and pedobarography are necessary due to a common agreement among the studies that radiography results may not provide a comprehensive clinical assessment [47, 50, 51, 63, 75, 77, 79, 84, 87, 95].

Improving documentation of complications requires using precise definitions, avoiding interchangeable terms like “under-correction” and “recurrence” or “non-union” and “pseudoarthrosis.” For example, ‘recurrence’ denotes radiographic loss of correction > 5° post-operatively, and ‘under-correction’ indicates residual deformity at the first post-operative assessment. The higher recurrence rates seen in LCL and CS may be due to study biases rather than treatment differences. Meanwhile, surgeries like SA have reported more hardware-related complications. Due to a limited number of participants, short follow-up periods, and potential biases, recurrence rates and complications might be underreported or misinterpreted, making comparisons between methods unreliable.

Due to substantial heterogeneity in outcome definitions, follow-up intervals, and reporting formats, a quantitative meta-analysis was not feasible; we therefore present a narrative synthesis. As summarized in Table 1, complication profiles varied by procedure: lateral column lengthening most commonly showed calcaneocuboid joint–related problems (e.g., subluxation/degeneration) alongside reports of recurrence or under-correction, while infections were uncommon and union generally reliable. Extra-articular subtalar arthrodesis demonstrated variable union quality, with instances of graft resorption or nonunion and occasional donor-site morbidity, though several series reported solid fusion with minimal wound issues. Arthroereisis predominantly featured implant-related events (migration/dislocation and sinus tarsi pain), often resolving after implant removal. Across studies, hardware-specific complications (e.g., screw migration/breakage), cast-related skin problems, and reoperations were reported sporadically, with wide between-study variability in frequency (Table 1).

Re-synthesizing the data by categories rather than by individual techniques changes both the risk of bias and the clinical reading of the results. Because the techniques have different indications and underlying biomechanics, pooling them or informally comparing their technique-level meta-estimates, risks confounding by indication; grouping them into joint fusions, joint-sparing osteotomy (LCL), and arthroereisis (SA) explicitly contains that clinical heterogeneity within categories, which is the approach recommended when interventions are not sufficiently similar for cross-group pooling. In practice, the category-wise models in Table 7 and Fig. 9 smooth idiosyncratic study or technique effects, lessen the influence of small subseries, and deliver category-specific mean differences that are easier to act on in decision pathways.

The limitations of this review include difficulty in assessing the strength of synthesis results due to frequent data gaps. The studies, often retrospective case series, lacked comparator treatments, leading to incomplete pre- and post-operative evaluations and a higher risk of bias in clinical and radiographic outcomes. Many publications did not provide P-values to demonstrate the statistical significance of radiographic findings and failed to correlate these with clinical outcomes, limiting their practical value. The evidence from prospective and comparative studies was weakened by small sample sizes and short follow-up periods. Longer follow-up is crucial for assessing potential degenerative changes in adjacent joints after fusion. Subgroup analyses by follow-up duration were underpowered in several strata; hence, non-significant p-values cannot be taken as evidence of no difference. Longer-term, adequately powered comparative cohorts are needed—especially for fusion techniques—to characterize time-dependent changes. Between-technique comparisons rely on pooled pre–post estimates from non-randomized cohorts; several arms (e.g., SA, TNA) had few studies and high heterogeneity, limiting comparative certainty despite large overall samples in other arms. In addition, many children with cerebral palsy undergo multilevel or combined foot surgeries, making it difficult to isolate the contribution of individual procedures. While our sensitivity analyses indicated that the inclusion of such studies did not substantially bias the pooled radiographic outcomes, the potential for residual confounding cannot be fully excluded. Combined procedures may influence both alignment and soft-tissue balance, leading to complex biomechanical interactions that cannot be fully disentangled through aggregated data. Therefore, the observed radiologic improvements should be interpreted as reflecting overall reconstructive correction rather than purely the effect of a single technique. This limitation highlights the need for future studies to report outcomes separately for isolated and combined interventions, enabling procedure-specific meta-analyses.

Conclusion

This systematic review and meta-analysis revealed that while different surgical approaches have specific advantages, no single technique is definitively the best. The majority of surgeries were conducted on children aged 11–12. We did not detect consistent time-related changes in exploratory subgroup analyses; however, limited sample sizes and heterogeneity preclude firm conclusions about stability over time. More research is necessary to enhance the reliability and accuracy of these findings, guiding better clinical decision-making for treating planovalgus in CP patients.

Authors’ contributions

Iman Menbari Oskouie: Methodology, Formal analysis, Writing - Original Draft. Nazanin Rahimdoost: Investigation. Amir Kasaeian: Methodology, Formal analysis. Farzad Pourghazi: Investigation. Maysa Eslami: Investigation. Alireza Arvin: Validation. Mohammad Hossein Nabian: Conceptualization, Supervision. Ana Presedo: Conceptualization, Supervision. Sepehr Metanat: Analysis, Revising the Manuscript. Iman Menbari Oskouie and Sepehr Metanat contributed eqaully on this work.

Funding

This study did not receive any funds for conducting or publication.

Data availability

The datasets generated during and/or analyzed during the current study are available from the corresponding author on reasonable request.

Declarations

Ethics approval and consent to participate

Not applicable.

Consent for publication

The authors all agree for the submission and publication of the manuscript.

Competing interests

The authors declare no competing interests.