Chronic reactive synovitis in patients undergoing ACL reconstruction and augmentation with tape-type sutures

Abstract

Introduction

Arthroscopic Anterior Cruciate Ligament Reconstruction (ACLR) with internal bracing and augmentation using tape-type sutures (TTS) has gained popularity due to its biomechanical advantages. However, concerns have emerged regarding chronic reactive synovitis, which can lead to graft failure and the need for revision surgery. The purpose of this research is to determine the prevalence of chronic reactive synovitis after TTS-reinforced ACLR.

Materials and methods

A retrospective review was conducted on a series of 84 patients who underwent arthroscopic ACL reconstruction with FiberTape or SutureTape augmentation, performed by a single surgeon in the year 2019.

Results

Of the 84 patients analyzed, 17 presented with at least two or more symptoms, including persistent instability, knee pain, swelling, stiffness, and local rise in temperature, within 3–45 months post-surgery. All required secondary surgery, either for synovectomy, and tape removal (8 cases) or revision ACLR (9 cases). Intraoperative histopathological analysis confirmed the diagnosis of reactive synovitis due to foreign body reaction. One year after the secondary surgery, all 17 knees showed satisfactory results. None of the patients experienced the pain, swelling, or instability that they had before the secondary surgery.

Conclusion

Foreign body synovitis was found in 17 symptomatic patients out of 84 (20.2 %) who underwent ACLR with TTS reinforcement one year. While this study does not establish a direct causal link between tape-type sutures and the development of synovitis, it emphasizes the significance of remaining vigilant for impending reactive synovitis as a complication, given the potential exposure of the knee to foreign body material.

Level of evidence

Level IV (Retrospective case series without a comparison group)

1. Introduction

Anterior Cruciate Ligament Reconstruction (ACLR) is a widely performed procedure to address knee instability following an ACL tear. Despite significant advancements in ACLR techniques over the years, including improvements in graft selection, preparation, anatomical positioning, and instrumentation, the risk of graft failure remains considerable. This failure often leads to knee laxity and may necessitate subsequent surgical intervention.¹ An ACL graft tear after ACLR can have severe consequences. Systematic reviews report autograft failure rates between 3 and 5%, which increase to 10–28 % in high-risk populations.^{2, 3, 4, 5} Additionally, the results of revision ACLR are typically worse than those of primary ACLR.^{6, 7, 8, 9} Hamstring tendon (HT) grafts are commonly used, although central quadriceps tendon (CQT) and peroneal grafts are also gaining popularity due to their unique benefits.^{10, 11, 12}

To improve graft tensile strength, the graft augmentation technique was initially introduced in the 1980s, but it was associated with high failure rates and complications.^13,14 Recently, reinforcement with tape-type sutures (TTS) has been described, showing promise in improving clinical outcomes by strengthening the graft after ACLR.^15,16 TTS functions as an "augmentation" device, acting as a "safety belt" to shield the autograft or allograft from excessive stress, especially during the remodeling phase, preventing stress shielding, in contrast to other synthetic devices that replace the biological function of the graft.¹⁵ The TTS is made of collagen-coated, ultrahigh-molecular-weight polyethylene/polyester tape, which enhances tissue integration and shields the graft while the healing process progresses through ligamentization, maturation, and reproduction.^15,16

The likelihood of graft failure after ACLR with or without TTS reinforcement depends on various factors, including surgical technique, accuracy of tunnel placement, graft choice, and postoperative rehabilitation. However, a notable drawback observed is the occurrence of chronic reactive synovitis, particularly in patients where TTS was used.

The purpose of this research is to examine a group of patients who had second-look arthroscopy after TTS-reinforced ACLR because their symptoms persisted and to determine the prevalence of chronic reactive synovitis in these patients. As far as we are aware, this is the 1st study to assess the presence of synovitis in multiple patients who underwent TTS-reinforced ACLR, synovectomy, suture removal, and, if necessary, revision ACLR, using both arthroscopic and histopathological evidence.

2. Materials and Methods

From January to December 2019, 98 patients underwent ACLR using HT autograft at a tertiary healthcare center. Of these, 84 patients received TTS reinforcement, primarily due to a thinner graft (≤9 mm) and the need for a quicker return to impact activities. A cohort of 84 patients was selected for this study.

2.1. Technique of primary surgery

Standard arthroscopic evaluation of the knee was done for all patients under general anesthesia using a 2.9-mm arthroscope through the anterolateral and anteromedial portals and the ACL tear was identified. The presence of intra-articular pathology (meniscal tears, loose bodies, and chondral lesions) was also checked. The ACL tear was debrided, leaving as much remnant as possible. Semitendinosis and Gracilis were harvested, marked, and measured for thickness. The tape was added to the graft and whipstitched. It was then looped with the graft in the endobutton of the adjustable loop on the femoral side. The tibial side was kept free. The femoral footprint was marked using a microfracture awl. Standard femoral tunnel placement was done distal to the lateral intercondylar ridge and posterior to the bifurcate ridge. A flexible reamer system was used and with the help of a 7 mm offset guide, the femoral tunnel was drilled using an accessory anteromedial portal. The tibial ACL jig was set at 55–60°, positioned at the ACL footprint adjacent to the anterior horn of the lateral meniscus within the ACL tibial remnant, and the tibial tunnel was drilled. The graft along with the tape was passed through the drilled tunnels with the knee in 30-degrees flexion and a posterior drawer. The graft was tensioned sufficiently and fixed on the tibial side using aperture fixation methods (interference screw/suture disc) based on the length of the graft achieved.

2.2. Follow up

A retrospective review identified 17 patients who experienced pain, swelling, and/or symptomatic instability within 3–45 months after the primary surgery (Table 1). Before a repeat arthroscopy was carried out, these patients were clinically assessed and radiological investigations were done in the form of MRI scans, for their persistent knee issues. MRI scans revealed an inflammatory response with edema surrounding the ACL graft (Fig. 1), and blood parameters were within normal limits. Before the second surgery, all patients gave their informed consent so that the results could be evaluated. The patients were also given a thorough explanation of the potential outcomes of the research that would be done.

Table 1.

Baseline details of the study.

Patient	Gender	Age (at primary surgery)	Activity level	Lapse (months from primary ACLR to second-look arthroscopy)	Indication for second-look arthroscopy	Stability of ACL at EUA (Lachman, Pivot Test)	Arthroscopic picture and visualised graft integrity	Synovitis visualised on arthroscopy	Synovium histology
1	F	18	Highly active	44 M	Persistent instability & pain	Gd 3 Lachman, no pivot	Complete failure of graft, MM tear	Reactive	Moderate chronic synovitis with rare giant cells
2	M	32	Moderately active	42 M	Pain & swelling	Gd 2 Lachman, no pivot	Complete failure of graft	Reactive	Moderate chronic synovitis with rare giant cells
3	M	41	Lightly active	44 M	Pain & swelling	Stable	Intact graft	Reactive	Mild chronic synovitis with rare giant cells
4	F	33	Moderately active	41 M	Pain & swelling	Stable	Intact graft	Reactive	Mild chronic synovitis with rare giant cells
5	F	19	Highly active	3 M	Persistent instability	Gd 3 Lachman, no pivot	Complete failure of graft, MM tear	Reactive	Moderate chronic synovitis with rare giant cells
6	M	19	Moderately active	44 M	Pain & swelling	Gd 2 Lachman, no pivot	Complete failure of graft	Reactive	Moderate chronic synovitis with rare giant cells
7	M	28	Highly active	23 M	Persistent instability	Gd 3 Lachman, no pivot	Complete failure of graft, MM tear	Reactive	Moderate chronic synovitis with rare giant cells
8	F	27	Moderately active	29 M	Pain & swelling	Stable	Intact graft	Reactive	Mild chronic synovitis with rare giant cells
9	F	24	Lightly active	41 M	Pain & swelling	Gd 2 Lachman, no pivot	Complete failure of graft, MM tear	Reactive	Moderate chronic synovitis with rare giant cells
10	F	26	Moderately active	45 M	Pain & swelling	Stable	Intact graft	Reactive	Mild chronic synovitis with rare giant cells
11	M	23	Highly active	37 M	Pain & swelling	Stable	Intact graft, MM tear	Reactive	Mild chronic synovitis with rare giant cells
12	M	25	Moderately active	28 M	Persistent instability	Gd 3 Lachman, no pivot	Complete failure of graft, MM tear	Reactive	Moderate chronic synovitis with rare giant cells
13	M	38	Moderately active	33 M	Pain & swelling	Stable	Intact	Reactive	Mild chronic synovitis with rare giant cells
14	M	39	Lightly active	39 M	Pain & swelling	Stable	Intact, MM tear	Reactive	Moderate chronic synovitis with rare giant cells
15	M	22	Highly active	34 M	Pain & swelling	Gd 2 Lachman, no pivot	Complete failure, MM tear	Reactive	Moderate chronic synovitis with rare giant cells
16	M	36	Moderately active	33 M	Pain & swelling	Stable	Intact	Reactive	Moderate chronic synovitis with rare giant cells
17	F	24	Moderately active	26 M	Persistent instability	Gd 3 Lachman, no pivot	Complete failure	Reactive	Moderate chronic synovitis with rare giant cells

Fig. 1.

MRI proven synovitis after ACLR with TTS augmentation (Fig. 1A – T2 sagittal section, Fig. 1B – T2 coronal section).

2.3. Revision surgery in symptomatic patients

A clinical assessment of the stability of the primary ACL-TTS augmented construct was conducted through an examination under anesthesia (EUA) before repeat arthroscopy. This included a global knee examination along with the Lachman & pivot shift tests. The second procedure was carried out by the same surgeon who carried out the first ACLR. The synovium in each compartment was first diagnostically assessed, and its appearance was recorded as either reactive, inflammatory, or normal, in accordance with Ayral et al.¹⁷ The notch was then examined for graft integration and any residual suture tapes. Apart from the visual assessment, a probe was used to test the construct's integrity and assign a grade of intact, partially failed, or completely failed.

From each knee, a synovial biopsy was obtained and sent for histopathological analysis, along with the retrieved suture tapes. The biopsies were inspected for evidence of a foreign body reactive process and synovitis. A formal synovectomy was performed, and the tapes were removed. In cases of graft failure, revision ACLR was executed using the CQT (central quadriceps tendon) autograft. In individuals suffering from irreparable medial meniscus tears within the white-white zone, the tears were satisfactorily trimmed. The bone tunnels were found to be adequately placed in all cases, and thus, the same tunnels were used but were redrilled to freshen the bone surface. Standard revision ACLR surgical principles were followed, including bone tunnel drilling using a flexible reamer system, anatomic graft placement, and femoral-end aperture fixation with an adjustable loop, depending on graft length, and thus, any bias related to the surgical technique being the cause of synovitis was ruled out.

2.4. Rehabilitation protocol

All the revision ACLR patients participated in a standardized rehabilitation program overseen by licensed physiotherapists thereby ruling out another bias of postoperative rehabilitation being a cause of the synovitis. During the 1st two weeks, all patients had been permitted to use a walker to bear weight as tolerated, as there were no meniscus repairs involved. Static quadriceps strengthening and assisted straight leg raises were initiated as soon as the pain subsided in the first week. Knee range of motion (ROM) gradually progressed to 90–100° within the first two weeks. Wall squats, independent straight leg raises, as well as hamstring curls were introduced 2–6 weeks later, depending on tolerance. Full weight-bearing without walker support was achieved within 4–6 weeks. Between 6 weeks and 3 months, outdoor cycling and straight-line jogging were gradually introduced. All patients could resume their pre-injury activity levels within three months, although impact activities, including brisk running, were only resumed after 6 months.

2.5. Follow-up

Following the revision of ACLR, postoperative follow-up was carried out at two weeks, six weeks, three months, and one year. All knees underwent evaluations for Tegner Lysholm (TL), International Knee Documentation Committee (IKDC), and ROM after a year (Table 2), which was documented by SU, BS, and AS, apart from the primary surgeon (AJ), to avoid any selection bias.

Table 2.

1-year results after revision ACLR.

Patient	ROM	IKDC SCORE	TL SCORE
1	Full	86.2	90
2	Full	93.1	90
3	Full	87.4	90
4	Mild stiffness	78.2	81
5	Full	91.3	85
6	Full	83.9	90
7	Full	93.1	90
8	Full	87.4	95
9	Full	82.8	81
10	Full	91.3	100
11	Full	88.5	90
12	Full	92.0	94
13	Full	86.2	90
14	Full	87.4	94
15	Full	91.3	85
16	Full	93.1	89
17	Full	88.5	87

3. Results

The study comprised 17 patients, 10 of whom were male and 7 of whom were female, whose mean age at primary ACLR was 27.88 years (range: 18–41) (Table 1). 3 patients were lightly active (Exercise 1–3 days per week with a desk job), 9 were moderately active (Exercise 3–5 times per week with an active lifestyle), 5 patients were highly active (Exercise 6–7 days per week with a rigorous job and an active lifestyle). 55.9 days on average (range: 22–132 days) passed between the ACL injury and the primary ACLR with TTS augmentation. The second-look arthroscopy and the initial ACLR surgery were separated by an average of 34.47 months (range: 3–45 months). The primary indications for repeat arthroscopy were persistent instability, knee pain, swelling, stiffness, and localized rise in temperature, with 5 out of 17 knees exhibiting symptomatic non-traumatic instability.

Eight knees were clinically stable, according to EUA, while five knees had a grade 3 Lachman test as well as four had a grade 2 test. There was no pivot shift in any of the knees. Upon assessing the ACL graft construct, 8 out of 17 knees had an intact graft, while the remaining 9 knees showed complete graft failure, especially near the femoral tunnel aperture.

A qualitative arthroscopic evaluation, based on the Ayral classification, revealed reactive synovitis in all 17 knees (Fig. 2). The reinforcement tapes used were either SutureTape (Arthrex) or FiberTape (Arthrex). Additionally, 8 patients had irreparable medial meniscus tears in the white-white zone, which were satisfactorily trimmed during the procedure. Histopathological analysis indicated chronic hypertrophic synovitis in all 17 knees—mild in 6 cases and moderate in 11 cases—with the presence of rare giant cells consistent with a foreign body reaction (Fig. 3).

Fig. 2.

Arthroscopic picture showing failure of the graft construct with synovitis.

Fig. 3.

Histopathological image (low power 20× magnification) showing chronic hypertrophic synovitis with rare giant cells, consistent with a foreign body material.

At the one-year postoperative follow-up, all 17 knees demonstrated satisfactory results in terms of ROM, IKDC scores, and TL scores. All knees achieved full ROM after one year, except for one knee that exhibited mild correctable stiffness. The mean IKDC score at one year was 88.34 ± 4.13, and the mean TL score was 89.47 ± 4.84 (Table 2). None of the patients reported pain, swelling, or persistent instability, as was experienced before the surgery.

4. Discussion

The most significant finding in this case series is the identification of chronic foreign body synovitis in multiple knees following ACLR with TTS augmentation, particularly in cases where graft failure occurred. Foreign material was consistently found within the synovial tissue by histopathological analysis, indicating that it might be a factor in graft attrition, fraying, or else rupture, which ultimately results in the development of synovitis.

The knee synovium is highly sensitive to the presence of foreign materials, which can provoke an inflammatory response characterized by leukocytic exudation and lymphomonocytic infiltration.^18,19 Previous studies have documented synovial reactions to foreign bodies in the context of synthetic grafts used for ligament reconstruction.^19,20 Struewer et al. reported a 31 % incidence of synovial reaction among patients having additional arthroscopy procedures to remove polyethylene-based ACL graft augments, which is the same material used in the tape-type sutures in our series.²¹ However, their study did not include a biopsy or histological examination to correlate these findings, whereas our series did.

In our study, all 17 patients exhibited reactive synovitis, confirmed through clinical, arthroscopic, and histopathological evidence. In contrast, Parchi et al. and Batty et al.'s two most recent systematic reviews found the rates of synovitis to be as low as 0.24 and 0.2 %, respectively.^13,22 While this is a small number as compared to ours, they have stated that half of the articles they reviewed made no mention of this important outcome, and thus, this strengthens our cause even further to stay cautioned about the chances of this complication occurring.

The existence of foreign body material in synovial biopsies suggests that the breakdown of the ultra-high molecular weight polyethylene (UHMWPE) used in tape-type sutures may contribute to the observed synovitis. These sutures, known for their high stiffness as well as ultimate load to failure, are biomechanically superior to other materials like FiberWire (Arthrex), but their byproducts are less inert and more likely to provoke a synovial reaction.^19,20 The arthroscopic evidence of reactive synovitis may be dose-dependent, related to the volume of polyethylene particles present in the knee.²⁰

While tape-augmented reconstruction is biomechanically stronger, with reduced elongation under cyclic loading and less post-operative knee laxity compared to standard ACLR, there is limited research on late-onset synovial complications.²³ For instance, Tulloch et al. discovered chronic hypertrophic synovitis in 7 out of 12 knees following LARS ACLR, which also uses polyethylene, and Cook et al. reported similar rates of synovitis and effusion in canine knees that were augmented with tape and those that were not at six months.^19,24

To our knowledge, this is the first study to document chronic reactive synovitis 2–3 years after primary ACLR with TTS reinforcement. Our findings show that approximately 20 % (17/84) of the entire cohort of knees that underwent ACLR with tape-type suture augmentation developed histologically confirmed foreign body synovitis. Despite the small sample size, this study underscores the need for caution and further research to determine whether synovitis is a consequence of natural graft wear or a specific reaction to the tape-type sutures. While this study is not completely against the use of TTS for ACLR, the authors recommend that more vigilance is needed during follow-up evaluations of these patients and any symptom pointing towards possible development of synovitis should be documented and addressed immediately.

While the presence of foreign material in synovial biopsies is a significant finding, the study cannot rule out other contributing factors, such as natural graft wear, as possible contributors to synovitis, and thus, a large sample size is required for the same. Also, the lack of a control group without TTS reinforcement limits the ability to attribute synovitis directly to the TTS. Since this is a retrospective study, the authors believe that more prospective study designs with control groups to investigate the relationship between TTS and synovitis would provide further insight into defining this complication. Despite these shortcomings of the relatively smaller sample size and retrospective nature of the study, some key findings emerged from the study highlighting the need to be vigilant about introducing a foreign material in the knee joint. The nature of these augmenting sutures or tapes may be varied and each of the materials and techniques should undergo vigorous pre-clinical testing and post-launch surveillance to ensure that any adverse reactions are reported promptly.

5. Conclusions

Foreign body synovitis was relatively common in our series of patients undergoing repeat arthroscopy after ACLR with TTS reinforcement. In almost half of the symptomatic cases, synovitis was linked to graft failure (9/17). This study emphasizes the significance of remaining vigilant for reactive synovitis as a potential complication following ACLR with tape-type suture reinforcement. This can be done by maintaining careful follow-ups, early diagnosis of any symptoms related to synovitis, and prompt management of the same, preventing the risk of revision surgery.

CRediT authorship contribution statement

Anant Joshi: Conceptualization, Methodology, Supervision. Aashiket Sable: Validation, Formal analysis, Investigation, Resources, Data curation, Writing – original draft, Writing – review & editing, Visualization, Project administration. Sajeer Usman: Methodology, Validation, Supervision. Bhushan Sabnis: Methodology, Validation, Supervision. Vaibhav Bagaria: Validation, Writing – review & editing, Visualization, Supervision, Project administration.

Consent to participate

Informed consent was obtained from all patients before the second surgery for evaluating their results and the prospects of research to be undertaken were explained to the patients in detail.

Availability of data and materials

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

Consent for publication

We agree to the consent for publication.

Ethical statement

Since it was a retrospective observational study, ethical clearance was not required and hence, an exemption sought.

Funding

None.

Competing interests

The authors declare that they have no competing interests.