1 Introduction

Progressive collapsing foot deformity (PCFD), commonly known as adult-acquired flatfoot, is a prevalent and debilitating condition affecting up to 10 % of the adult population.¹ While some individuals have a congenital, flexible pes planus, PCFD is a pathologic condition characterized by gradual and painful collapse of the medial longitudinal arch of the foot.^2,3 Surgical management of PCFD is complex, with a wide array of procedures designed to address its multi-planar deformities. Some surgical management options including medializing calcaneal osteotomy (MCO), lateral column lengthening (LCL), and flexor digitorum longus (FDL) tendon transfer.^4–6

Alongside the posterior tibial tendon (PTT), a cornerstone of the medial arch's stability is the spring ligament complex, a group of ligaments connecting the calcaneus to the navicular that functions as an important static support for the talar head.⁷ In addition to the PTT, the spring ligament prevents talar plantarflexion and medial deviation, which strengthens the arch's structure and helps prevent the formation of flatfoot deformity.⁸ Insufficiency or tearing of the spring ligament is a primary pathology in the development of PCFD, with presence in over 70 % of patients undergoing surgery for the condition.⁹ Spring ligament injuries can result from chronic attenuation or acute trauma, with patients often presenting with medial ankle pain, swelling, and a flattening of the medial arch. Although PTT dysfunction was once regarded as the primary cause of flatfoot deformity, current evidence highlights spring ligament failure as a critical contributing factor.^10–12 The existing literature describes several operative techniques for managing spring ligament injuries, however the variability among approaches makes it challenging to determine the optimal surgical treatment method. While suture-based augmentation has been introduced as an adjunct to ligamentous repair, its clinical benefit in the setting of spring ligament repair remains uncertain.

To date, no systematic review has comprehensively evaluated the outcomes following spring ligament repair performed with and without augmentation. The purpose of this systematic review is to evaluate the radiographic findings, clinical outcomes, complications, and failures following spring ligament repair with and without augmentation in the setting of PCFD.

2 Methods

3 Results

3.1

3.1 Study characteristics and patient demographics

The search generated 612 studies, published between 1974 and 2025. Of these, 9 met the inclusion and exclusion criteria (Fig. 1). Study characteristics and patient demographics are listed in Table 2. Three of the included studies were LOE III and 6 were LOE IV.^15–23.

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Fig. 1 Preferred reporting items for systematic reviews and meta-analyses (PRISMA) flowchart.

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Table 2 Study characteristics and patient demographics.

Spring Ligament Repair
Author (Year)	LOE	Patients (n)	Feet (n)	Follow-up Time (mo)	Age (years)	M/F	Right/Left	BMI (kg/m2)	Flatfoot Stage	Concomitant Flatfoot Procedure
Gazdag et al. (1997)	IV	18	18	31.3 ± 6.9	57.7 ± 10.6	2/16	−/−	–	–	FDL tendon transfer
Masaragian et al. (2023)	IV	11	11	21.9	46.0 ± 11.3	7/4	2/9	–	IA: 1IB: 3IIC: 7	MCO, LCL, cuneiform osteotomy, PTT debridement and resection
Orr et al. (2013)	IV	6	6	13.0 ± 3.3	42.0 ± 13.5	0/6	3/3	–	–	MCO, LCL, cuneiform osteotomy
Raikin et al. (2021)	III	35	35	45.9 ± 13.4	57.0 ± 7.7	13/22	–	30.6 ± 5.1	IIB: 35	PTT debridement and resection, FDL tendon transfer, LCL, cuneiform osteotomy
Tang et al. (2020)	III	22	22	21.8	64.8 ± 6.3	7/15	–	–	IIA: 22	FDL tendon transfer, MCO

Spring Ligament Repair + Augmentation
Author (Year)	LOE	Patients (n)	Feet (n)	Follow-up Time (mo)	Age (years)	M/F	Right/Left	BMI (kg/m2)	Flatfoot Stage	Concomitant Flatfoot Procedure
Fogleman et al. (2021)	IV	57	57	15.5 ± 11.6	57.5 ± 13.8	19/38	22/35	32.2 ± 7.0	–	Achilles tendon lengthening, FDL tendon transfer, MCO, PTT debridement, cuneiform osteotomy, LCL
García-Jarabo et al. (2023)	IV	20	23	21.5 ± 5.0	63.0 ± 6.8	3/17	–	–	IIB: 23	FDL tendon transfer, LCL, cuneiform osteotomy, MCO
Palmanovich et al. (2017)	IV	5	5	–	49.4 ± 7.5	3/2	–	–	–	PTT repair, MCO
Heyes et al. (2020) (synthetic ligament)	III	17	17	12.0 (minimum)	49.1 ± 13.3	6/11	4/13	28.6 ± 2.1	–	Gastrocnemius resection, PTT advancement, FDL tendon transfer, calcaneal osteotomy
Tang et al. (2020)	III	18	18	21.8	65.1 ± 7.8	4/14	–	–	IIA: 18	FDL tendon transfer

In total, there were 92 patients (92 feet) who underwent spring ligament repair.^{17,19–21,23} There were 29 (31.5 %) males and 48 (63.0 %) females who underwent spring ligament repair.^{17,19–21,23} Of these 92 patients, the weighted mean age was 56.7 ± 8.7 years (range 42.0–64.8 years), with a weighted mean follow-up time of 32.3 ± 6.7 months (range 13.0–45.9 months)0.^{17,19–21,23} Of the two studies that reported on laterality, 5 (29.4 %) right feet were operated on and 12 (70.6 %) left feet were operated on.^17,20 One study reported a mean BMI of 30.6 ± 5.1 kg/m².²¹ Of the three studies that reported flatfoot stage, 1 (1.5 %) patient had stage IA, 3 (4.4 %) patients had stage IB, 22 (32.4 %) patients had stage IIA, 35 (51.5 %) patients had stage IIB, and 7 (10.3 %) patients had stage IIC.^17,21,23 For patients who underwent spring ligament repair, concomitant flatfoot procedures consisted of FDL tendon transfer, MCO, LCL, PTT debridement and resection, and cuneiform osteotomy.^{17,19–21,23}.

In total, there were 117 patients (120 feet) who underwent spring ligament repair with augmentation.^{15,16,18,22,23} There were 35 (29.9 %) males and 82 (70.1 %) females who underwent spring ligament repair with augmentation.^{15,16,18,22,23} Of these 117 patients, the weighted mean age was 58.0 ± 11.3 years (range 49.1–65.1 years), with a weighted mean follow-up time of 17.1 ± 9.9 months (range 12.0–21.8 months).^{15,16,18,22,23} Of the two studies that reported on laterality, 26 (35.6 %) right feet were operated on and 47 (64.4 %) left feet were operated on.^15,16 The weighted mean BMI of these two studies was 31.4 ± 5.9 kg/m² (range 28.6–32.2 kg/m²).^15,16 Two studies reported on flatfoot stage, with 18 patients having stage IIA and 23 patients having stage IIB.^22,23 For patients who underwent spring ligament repair with augmentation, concomitant flatfoot procedures consisted of Achilles tendon lengthening, FDL tendon transfer, MCO, LCL, PTT repair, and cuneiform osteotomy.^{15,16,18,22,23}

4 Discussion

The most important finding from this systematic review is that spring ligament repair with and without augmentation results in clinically meaningful improvements in patients with PCFD. Both patient cohorts demonstrated improvements in radiographic alignment and clinical outcomes, with low associated complication and failure rates.

Anatomical repair of the spring ligament is often warranted for patients whose spring ligament is torn, regardless of the status of the PTT.²⁴ In the setting of PCFD intervention, spring ligament repair is also indicated when arch corrections have been attempted but significant subluxation persists in the talonavicular and subtalar joints.²⁵ Once the spring ligament has been repaired, the medial longitudinal arch alleviates strain on the foot, improving patient reported outcome measures.²⁶ By restoring static support to the talar head and stabilizing the medial arch, spring ligament repair corrects the biomechanics of PCFD, therefore leading to improvements in clinical outcome scores as demonstrated in the current review. Patients who underwent spring ligament repair demonstrated large improvement in TFMA, with correction of 12.9° on lateral radiographs, which has been demonstrated as the most accurate radiographic angle for evaluating flatfoot.²⁷ Isolated spring ligament repair directly restores the native ligament's tension and alignment without introducing additional augmentation or graft material, ultimately providing significant radiographic improvement. Finally, patients who underwent spring ligament repair experienced low complications and failures. By avoiding the added complexity and potential risks associated with grafts in reconstructive procedures, isolated spring ligament repair may be associated with lower complication and failure rates. Of note, isolated spring ligament repair is often performed in patients with adequate native ligament tissue quality and less advanced deformity, which may influence the observed lower complication and failure rates compared to patients who received augmentation. Spring ligament repair is an effective treatment option for patients with spring ligament injuries, providing clinical and radiographic improvements with low associated complication and failure rates.

The utilization of suture augmentation has emerged as a popular adjunct in ligamentous repair throughout the body, with promising outcome measures.^28,29 Suture augmentation often includes the use of a high-strength, non-absorbable suture that acts as an internal brace.³⁰ The augmentation provides mechanical stability to the native ligament and protects the healing structure from excessive load.³¹ In the setting of PCFD, suture augmentation may be particularly beneficial in patients with compromised ligament quality or concern for residual deformity following surgical intervention. The additional mechanical support provided from the suture augmentation further enhances medial arch stability and improves hindfoot alignment, ultimately allowing for improved clinical outcome measures such as AOFAS. Furthermore, the reinforcement of the suture augmentation maintains talar alignment and medial arch height, improving radiographic findings such as TFMA, calcaneal pitch, and TN uncoverage. Previous literature has found that suture augmentation may reduce the risk of recurrent deformity in patients who undergo other ligamentous procedures such as anterior talofibular ligament (ATFL) repair.³² In the current systematic review, patients who underwent spring ligament repair with augmentation demonstrated favorable clinical and radiographic outcomes with low complication (6.7 %) and failure (3.3 %) rates. Spring ligament repair with augmentation is an effective treatment option for PCFD, providing clinical and radiographic outcomes comparable to those observed with isolated spring ligament repair.

In the cases of chronic, degenerative tears where the native ligament tissue is severely compromised, direct repair is often not feasible. In these settings, ligament reconstruction with a tendon graft is the indicated treatment option.^33,34 The grafts utilized are passed through bone tunnels in the calcaneus and navicular to create a new ligament to support the talar head. The technique provides a durable biological replacement that integrates with the host bone, offering a solution that provides improvement in pain and function. Williams et al. reported on 13 patients who underwent spring ligament reconstruction using a peroneus longus autograft, demonstrating substantial improvement in AOFAS scores from 43.1 pre-operatively to 90.3 at final follow-up.³⁵ These clinical improvements are consistent with those reported following spring ligament repair, suggesting that reconstruction may achieve comparable patient reported outcomes when appropriately indicated. However, higher complication and failure rates have been reported in reconstruction cohorts, likely reflecting the greater surgical complexity and more advanced deformity in these patients. For example, Kim et al. evaluated 27 feet treated with spring ligament reconstruction using Achilles or hamstring allografts and reported complications in 10 cases (37.0 %), most often due to painful hardware.²⁶ Tendon graft reconstruction frequently requires fixation hardware which can become prominent, ultimately irritating surrounding structures and leading to discomfort in patients.³⁶ Furthermore, Heyes et al. found that among 16 patients who underwent spring ligament reconstruction with hamstring allograft, 3 patients (18.8 %) experienced failure requiring reoperation, whereas in their spring ligament repair cohort, only 1 patient (5.9 %) required reoperation from failure. Following reconstruction, grafts require time for biological incorporation at the new anatomical site, making the ligament more susceptible to stretching or suboptimal loading, which may contribute to failure of the procedure.³⁷ In contrast, primary repair preserves native ligament and anatomic attachments, which may facilitate greater healing and reduce the risk of surgical failure.

5 Conclusion

Spring ligament repair with and without augmentation is associated with meaningful improvements in radiographic alignment and clinical outcomes in patients with PCFD. Across the included studies, both treatment approaches also demonstrated low complication and failure rates. While suture augmentation may provide additional mechanical support in select patients, the available evidence precludes direct comparative conclusions regarding the superiority of the technique over isolated spring ligament repair. Further high-quality, comparative studies are warranted to definitively establish the optimal surgical method for managing spring ligament injuries.

Patient consent

There was no guardian or patient consent for this study as it was a systematic review and did not use primary patient data.

IRB statement

No IRB approval was required as this was a systematic review of published peer reviewed studies.

Ethics approval statement

No ethical approval was required for this study.

CRediT authorship contribution statement

Jared Rubin: Writing – review & editing, Writing – original draft, Investigation, Formal analysis, Data curation, Conceptualization; Alexander Tham: Writing – review & editing, Supervision, Project administration, Methodology, Data curation, Conceptualization. Reed Macey: Writing – original draft, Writing – review & editing, Validation, Supervision, Investigation, Conceptualization. Nathaniel Mattera: Writing – review & editing, Data curation, Validation. Michael Allen: Writing – original draft, Writing – review & editing, Data curation. Samuel Montgomery: Writing – original draft, Writing – review & editing, Data curation. Megan Donnelly: Writing – review & editing, Validation, Supervision, Project administration, Methodology, Investigation. Jay Zaifman: Writing – review & editing, Validation, Supervision, Project administration, Formal Analysis. John Kennedy: Writing – review & editing, Writing – original draft, Validation, Supervision, Resources, Project administration, Methodology, Investigation.

Funding statement

This research did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sectors.