Early Failures of Polyvinyl Alcohol Hydrogel Implant for the Treatment of Hallux Rigidus

Current Utilization of Gel-Based Scaffolds and Templates in Foot and Ankle Surgery-A Review

As tissue engineering and regenerative medicine (TERM) continues to revolutionize medicine and surgery, there is also growing interest in applying these advancements to foot and ankle surgery. The purpose of this article is to provide a comprehensive review of the types of gel scaffolds and templates, their applications in foot and ankle surgery, the challenges with current utilization, and the future directions of TERM in foot and ankle surgery. With multiple compelling scaffold prospects across the numerous natural, synthetic, and hybrid polymers currently utilized in TERM, promising results have been described in the treatment of osteoarthritis (OA) and osteochondral lesions (OCLs). However, concerns with material biocompatibility, structural integrity, feasibility during surgery, and degradation still exist and limit the extent of utilization. As researchers continue to develop enhanced polymers and formulations that address current issues, there are many opportunities to increase applications across foot and ankle surgery.

Revision Surgery for Failed Polyvinyl Alcohol Hydrogel Implant in the First MTP Joint: A Case Report and Comprehensive Review

Background

Hallux rigidus is a degenerative condition of the first metatarsophalangeal (MTP) joint that can significantly impair function and quality of life. The introduction of polyvinyl alcohol (PVA) hydrogel implants, such as Cartiva, offered an alternative to arthrodesis by preserving joint motion. However, failures of these implants, often resulting in bone loss and joint instability, present a challenge for revision surgery.

Methods

We report the case of a 43-year-old woman with persistent pain and functional limitations after a failed PVA hydrogel implant in the first MTP joint. The revision surgery involved a biologic resurfacing using the Osteochondral Autograft Transfer System (OATS) with a graft harvested from the ipsilateral femoral condyle, complemented by interpositional arthroplasty with a dermal graft and a proximal phalanx closing wedge osteotomy to correct residual hallux valgus.

Results

At the 3-year follow-up, the patient-reported complete resolution of pain and returned to full activity with improved range of motion (40 degrees dorsiflexion, 15 degrees plantarflexion). Radiographic evaluation demonstrated graft incorporation and restoration of joint space, confirming the success of the procedure.

Conclusion

This case highlights the potential of OATS combined with interpositional arthroplasty as a viable option for revision surgery in complex cases of failed synthetic cartilage implants in hallux rigidus. By addressing bone loss and preserving joint function, this approach provides a patient-specific alternative to traditional arthrodesis. Further studies are warranted to establish the long-term efficacy of this technique in similar cases.

Level of Evidence

Level V, case report.

Midterm functional outcomes of synthetic cartilage implant (SCI) arthroplasty for hallux rigidus

Hallux rigidus is a common degenerative condition of first metatarso-phalangeal joint most commonly affecting patients above 50 years of age. The aim of our study is to evaluate the five-year results of synthetic cartilage implant (Cartiva) arthroplasty for hallux rigidus. A retrospective study of 70 patients who underwent synthetic cartilage implant interpositional arthroplasty were collected and analysed. Patients with Grade 3 to 4 hallux rigidus and who had failed conservative management were included. Patients who had previous forefoot surgery, hallux varus or valgus deformity of more than 250 and neuromuscular disease were excluded. Mean age at the time of operation was 63.4 years (range 42-84 years). The mean follow-up was 62.6 months. The functional evaluation was done using Manchester-Oxford Foot Questionnaire (MOxFQ). EQ-5D and EQVAS. 86 patients were matriculated in the study with 70 patients being assessed at five years. The average preoperative MOxFQ score improved from 35.74 (31.44-40.04) to 19.11 (11.31- 26.91) at one year after surgery. The EQ-5D scores improved from preoperative average of 9.40 (8.14-10.66) to 4.26 (2.09-6.43) at one year. The preoperative EQVAS was 61.66 (51.25-72.07) to 71.45 (60.87-82.03 at one year. At five years follow up the average MOxFQ score was 17.6 (9.92-24.38), EQ-5D - 4.8 (2.26- 6.45) and EQVAS - 72.48 (62.40-82.56). Three patients had revision to first MTP fusion due to ongoing pain. Synthetic cartilage implant has demonstrated clinical efficacy and good functional outcomes at the end of five years for the treatment of Hallux rigidus.

Cartiva interpositional arthroplasty versus arthrodesis in the treatment of Hallux rigidus: A retrospective comparative study with mean 2 year follow up

BACKGROUND

Hallux rigidus is a common condition characterised by first metatarsophalangeal joint (MTPJ) degeneration, pain and limited range of motion (ROM). The gold standard surgical treatment is arthrodesis, providing good pain relief, but sacrifices ROM. The Cartiva synthetic cartilage implant (SCI) has been utilised as an interpositional arthroplasty, aiming to reduce pain whilst preserving range of motion. Current evidence for Cartiva SCI is limited. The aim was to evaluate the clinical outcomes of Cartiva SCI compared to arthrodesis undertaken in our centre.

METHODS

A retrospective cohort study was conducted, enrolling all adult patients who underwent primary first MTPJ SCI arthroplasty or arthrodesis for the treatment hallux rigidus. The primary outcome was a validated patient-reported outcome measure (PROM), the Manchester-Oxford Foot Questionnaire (MOXFQ). Secondary outcomes included EQ-5D, complication rates, VAS Pain and FAAM (ADL).

RESULTS

Between 2017 and 2020 there were 33 cases divided into two groups (17 Cartiva SCI, 16 arthrodesis, mean age 59.0 ± 9.9 years) with a mean follow up of 2.3 years. There was no statistically significant difference in any of the MOXFQ, EQ-5D, VAS Pain or FAAM (ADL) outcome scores between the Arthrodesis and SCI groups (p > 0.05). The mean MOXFQ Index score was 7.2 ± 6.4 for the SCI group and 3.9 ± 5.8 for the Arthrodesis group at final follow up (p = 0.15). Although complications were high in both groups, the overall hallux reoperation rate was 29.4 % in the SCI cohort and 0.0 % for arthrodesis.

CONCLUSION

This retrospective comparative study found no significant superiority of Cartiva SCI over arthrodesis in terms of PROMs. Due to the higher rate of further surgical intervention in the SCI cohort, we recommend arthrodesis as the preferred surgical option for hallux rigidus.

LEVEL OF EVIDENCE

III.

Mid-term efficacy of the Cartiva synthetic cartilage implant in symptomatic hallux rigidus

Aims

The Cartiva synthetic cartilage implant (SCI) entered mainstream use in the management of first metatarsophalangeal joint (MTPJ) arthritis following the positive results of large trials in 2016. Limited information is available on the longer-term outcomes of this implant within the literature, particularly when independent from the originator. This single-centre cohort study investigates the efficacy of the Cartiva SCI at up to five years.

Methods

First MTPJ arthritis was radiologically graded according to the Hattrup and Johnson (HJ) classification. Preoperative and sequential postoperative patient-reported outcome measures (PROMs) were evaluated using the Manchester-Oxford Foot Questionnaire (MOXFQ), and the activities of daily living (ADL) sub-section of the Foot and Ankle Ability Measure (FAAM).

Results

Patients were followed up for a mean of 66 months (SD 7.1). Of an initial 66 cases, 16 did not return PROM questionnaires. A total of six failures were noted, with survival of 82%. Overall, significant improvement in both objective scores (MOXFQ and FAAM ADL) was maintained versus preoperatively: 18.2 versus 58.0 (p > 0.001) and 86.2 versus 41.1 (p > 0.001), respectively. The improvement was noted to be less pronounced in males. Subjective scores had deteriorated since early follow-up, with an interval decrease in patient satisfaction from 89% to 68%. Furthermore, a subset of cases demonstrated clinically important interval deterioration in objective scores. However, no specific patient factors were found to be associated with outcomes following analysis.

Conclusion

This study represents the longest-term independent follow-up in the literature. It shows reassuring mid-term efficacy of the Cartiva SCI with better-than-expected survival. However, deterioration in scores for a subset of patients and lower satisfaction may predict ongoing failure in this group of patients. Additionally, males were noted to have a lower degree of improvement in scores than females. As such, ongoing observation of the SCI to assess durability and survivability, and identify predictive factors, is key to improving patient selection.

Managing Hallux Rigidus in the Elite Athlete

Hallux rigidus can present a difficult problem to both competitive and elite athletic populations. Once an appropriate diagnostic workup has been performed, nonoperative management strategies, including anti-inflammatory medications, injection therapies, shoewear modifications, and orthotic devices, represent the mainstay conservative management options. Surgical management can be considered where an athlete's athletic performance is limited. A joint-sparing cheilectomy can provide a predictable return to sport at the most elite levels. The addition of a proximal phalangeal osteotomy can be considered when necessary. Arthroplasty or arthrodesis techniques can be used for persistent symptoms or progressive disease, but with less predictable outcomes.

Synthetic cartilage implant vs. first metatarsophalangeal arthrodesis for the treatment of hallux rigidus

BACKGROUND

This study evaluated the outcome of the Cartiva synthetic cartilage implant (SCI) in the treatment of hallux rigidus.

METHODS

In the present retrospective matched case-control study, we compared 18 patients with Cartiva SCI (mean follow-up: 17.7 months) to 18 patients with metatarsophalangeal joint arthrodesis (mean follow-up: 20 months) using multiple function measures, along with four specified visual analog subscales for pain. Pre- and postoperative radiographs were compared, and radiographic abnormalities were documented.

RESULTS

We observed no significant differences in function measures between groups. While both groups experienced significant pain reduction, the arthrodesis group reported significantly lower exertion pain than the Cartiva SCI group (p = 0.004). Radiographic abnormalities, including implant site enlargement (6/18, 33.3%), erosive changes of the metatarsal bone (11/18, 61.1%) or articular surfaces (10/18, 55.6%), and bright sclerotic margins (12/18, 66.7%), occurred in the Cartiva SCI group.

CONCLUSION

The present study showed good functional results and a high satisfaction rate after MTP joint arthrodesis, which is considered the gold standard surgical treatment for higher grade hallux rigidus. While the Cartiva SCI group did not show significant differences from the arthrodesis in most aspects of function and clinical scores, the arthrodesis group tended to have better results in terms of satisfaction, residual pain, and revision rate. Even after the short follow-up period, there were some remarkable radiographic findings in the Cartiva SCI group, the long-term effects of which are not yet evident, but which may lead to implant loss. Cartiva SCI has advantages for patients who prioritize postoperative mobility, but the potential risks should be considered in the patient's informed consent. Therefore, the present study highlights the importance of MTP joint arthrodesis for the treatment of hallux rigidus.

LEVEL OF EVIDENCE

Level IV - Retrospective matched case-control study.

The Philosophy of Surgical Success and Outcomes of Cartiva Versus Fusion

Noninferiority studies in surgery are, by their very nature, reductionist. They use multiple variables to generate a yes or no answer about the new device being tested. A binary outcome is appropriate for a regulatory agency such as the Food and Drug Administration, but the clinical situation is more nuanced. It is critical to understand the underlying philosophies and choices that go into trial design when a surgeon is recommending a new device. In the case of Cartiva, any of 3 reasonable alternative means of defining surgical success would have altered the final outcome of the MOTION trial. Additionally, using a more rigorous noninferiority margin rather than adding an additional cushion based upon the argument that motion alone had extra inherent value would have also led to failure of the trial to demonstrate noninferiority.

Cartiva: A Review of the Best Evidence

The Cartiva implant is a synthetic polyvinyl alcohol hydrogel cartilage substitute that is used as a treatment of first metatarsophalangeal joint arthritis. The implant was designed to relieve the pain associated with hallux rigidus while preserving or restoring range of motion. A summary of outcomes, reasons for these outcomes, and technique pearls will be reviewed here. Seminal articles and current evidence are all included in this article. The aim is for the surgeon to understand all the literature, allowing the surgeon to counsel their patients appropriately, optimize patient selection and to deal with complications.

Polyvinyl alcohol hydrogel implant for the treatment of hallux rigidus is associated with a high complication rate and moderate failure rate at short-term follow-up: a systematic review

PURPOSE

Moderate-to-severe hallux rigidus is a debilitating pathology that is optimally treated with surgical intervention. Arthrodesis produces reliable clinical outcomes but is limited by restriction in 1st metatarsophalangeal joint range of motion. The advent of polyvinyl alcohol hydrogel (PVA) implants have produced early promise based on initial trials, but more recent studies have called into question the efficacy of this procedure. The purpose of this systematic review was to evaluate the clinical and radiological outcomes following the use of PVA for hallux rigidus.

METHODS

The MEDLINE, EMBASE and Cochrane library databases were systematically reviewed using the preferred reporting items for systematic reviews and meta-analyses guidelines. 18 studies were included.

RESULTS

In total, 1349 patients (1367 feet) underwent PVA at a weighted mean follow-up of 24.1 ± 11.1 months. There were 168 patients (169 feet) included in the cheilectomy cohort and 322 patients (322 feet) included in the arthrodesis cohort. All 3 cohorts produced comparable improvements in subjective clinical outcomes. Postoperative imaging findings in the PVA cohort included joint space narrowing, peri-implant fluid, peri-implant edema and erosion of the proximal phalanx. The complication rate in the PVA cohort, cheilectomy cohort and arthrodesis cohort was 27.9%, 11.8% and 24.1%, respectively. The failure rates in the PVA cohort, cheilectomy cohort and arthrodesis cohort was 14.8%, 0.3% and 9.0%, respectively.

CONCLUSION

This systematic review demonstrated that PVA produced a high complication rate (27.9%) together with concerning postoperative imaging findings at short-term follow-up. In addition, a moderate failure rate (14.8%) and secondary surgical procedure rate (9.5%) was noted for the PVA cohort. The findings of this review calls into question the efficacy and safety of PVA for the treatment of hallux rigidus.

LEVEL OF EVIDENCE

IV.

Surgical Outcomes of Synthetic Cartilage Implant Hemiarthroplasty for Metatarsophalangeal Arthropathy

Introduction Metatarsophalangeal joint (MTPJ) arthropathy in the great toe causes considerable pain and debilitation, severely impacting quality of life. Traditional management options included conservative measures, steroid injections, and arthrodesis. New options include Cartiva, a synthetic cartilage hemiarthroplasty for the MTPJ. This prosthesis has evidence of improved pain and function without the sacrifice of joint movement seen with arthrodesis. However, the implant itself has mixed reviews. This study aims to identify the pre-, peri, and short-term post-surgical outcomes of Cartiva surgery and review the literature for existing reported outcomes. Methods We retrospectively reviewed a cohort of 22 consecutive Cartiva procedures between 2016 and 2022 in a single UK institution. Hospital records were analyzed for peri-operative complications, implant survival, additional operative interventions, patient-reported outcomes, and functional improvement. Results Twenty-one patients underwent Cartiva for the first MTPJ pathology and one for the third MTPJ pathology. Prior to surgery, 40.9% of patients had undergone alternative therapies, including MTPJ steroid injections (seven patients), cheilectomy (four patients), and bunionectomy (one patient). Total complication rates, inclusive of medical, surgical, and implant complications were 45.5% (10/22). Total reoperation rates were 18.2% (4/22) including two revisions to arthrodesis and two manipulations under anesthesia (MUA) with local anesthetic injection. At the final follow-up, 55% were still experiencing pain, 15% neurovascular symptoms, 10% swelling, and 50% stiffness or reduced range of movement. However, 85% of patients returned to usual activities of daily living within two years. Conclusion Cartiva surgery for metatarsophalangeal arthropathy has demonstrated outcomes of persistent pain, limited range of movement, and restricted function at short-term follow-up. Rates of reoperation and revision to arthrodesis were comparable with similar studies.

Assessment and Management of Atraumatic First Metatarsophalangeal Joint Pain

Nontraumatic pain in the first metatarsophalangeal joint is frequent and can be debilitating. The metatarsophalangeal joint complex comprises four articulating surfaces including the first metatarsal, the proximal phalanx, and tibial and fibular sesamoids, which are all contained within a synovial capsule. The most common causes of pain are hallux valgus and hallux rigidus. However, other diagnoses, such as functional hallux limitus, sesamoiditis, gout, and inflammatory autoimmune arthritis, need to be considered as well. A systematic approach is key to accurately diagnose the source of pain, which can sometimes be the result of more than one condition. The most important clinical information to obtain is a focused history, meticulous clinical examination based on understanding the precise anatomy and biomechanics of the first metatarsophalangeal joint, and analysis of the relevant imaging. Each pathology has a different treatment algorithm, as such, understanding the pathoanatomy and biomechanics is important in forming an effective treatment plan.

Philosophies of Surgical Care Are Embedded in Outcome Studies: An Illustrative Reanalysis of the Cartiva MOTION Trial

BACKGROUND

Subjective assumptions on the definition of surgical success are inherent to the design of clinical trials with a categorial outcome. The current study used reasonable alternative assumptions about surgical care to reassess data for the randomized controlled Cartiva trial (MOTION).

METHODS

Data from the published study were augmented by publicly accessible internal US Food and Drug Administration documents. As in the published report, 1-sided lower bound 95% CIs (LBCI95) for the difference of proportions were calculated for a series of alternative scenarios in which the assumptions underlying what constitutes surgical success were altered.

RESULTS

Using a noninferiority margin of -15%, the MOTION trial reported success based on a 1-sided LBCI95 of -10.9%. Each of the 3 independent alternative scenarios analyzed yielded results that altered the primary outcome of the trial: (1) eliminating failures based solely upon radiographs findings, thereby considering a painless pseudarthrosis as a success (1-sided LBCI95 of -15.9%), (2) considering only major surgical revision as a failure and discounting isolated hardware removal (1-sided LBCI95 of -15.1%), and (3) using a visual analog scale (VAS) pain threshold of <30 as the success criterion rather than a 30% reduction in VAS pain score (1-sided LBCI95 of -15.8%).

CONCLUSION

In this reanalysis, applying any of 3 reasonable alternative assumptions about the definition of surgical success to the data resulted in failure to prove noninferiority of Cartiva over arthrodesis, a reversal of the reported trial result. These results highlight the effect of subjective assumptions in the design of clinical trials with a categorical outcome and illustrate how differing philosophies about what constitutes surgical success can be pivotal in determining the final result.

LEVEL OF EVIDENCE

Level II, prospective comparative study.

One-year Follow-Up Results with Hydrogel Implant in Therapy of Hallux Rigidus: Case Series with 44 Patients

BACKGROUND

The Cartiva implant (CI) is being increasingly used in the surgical therapy of hallux rigidus. Despite a growing number of studies, numerous questions regarding patient selection remain unanswered.

PATIENTS AND METHODS

As part of a retrospective case series with prospective follow-up (average follow-up period: 12 months), a total of 44 patients (male/female = 16/28; mean age at the time of surgery: 55.4 years) with 44 CI were analysed (VAS, EFAS-, AOFAS-score). Using a correlation analysis and a machine learning algorithm, risk factors for therapy failure were investigated.

RESULTS

The overall survival rate of the CI was 93% at 12 months. The VAS, EFAS and AOFAS scores showed a significant improvement in comparison to the preoperative condition. The mobility of the metatarsophalangeal joint showed no increase. Patients with a medium osteoarthritis grade and a medium level of clinical restraint showed the greatest improvement in relation to their preoperative condition.

CONCLUSION

The CI can be seen as an effective therapy for hallux rigidus. Nonetheless, realistic patient expectations must be communicated.

Complications of Hallux Rigidus Surgery

Hallux rigidus can be treated with a variety of surgical procedures, including joint preserving techniques, arthrodesis, and arthroplasty. The most commonly reported complications for joint preserving techniques consist of progression of arthritis, continued pain, and transfer metatarsalgia. Although good outcomes have been reported for arthrodesis overall, careful attention must be paid to technique and positioning of the toe to avoid nonunion or malunion. Arthroplasty preserves motion but in the case of failure can present the additional challenge of bone loss. In these scenarios, the authors recommend distraction bone block arthrodesis with structural autograft.

Early Failure of a Polyvinyl Alcohol Hydrogel Implant With Osteolysis and Foreign Body Reactions in an Ovine Model of Cartilage Repair

BACKGROUND

Hemiarthroplasty using a polyvinyl alcohol (PVA) hydrogel synthetic implant has been suggested as a good alternative to arthrodesis for the treatment of hallux rigidus. However, failure rates as high as 20% have been recorded.

PURPOSE

To characterize the pathological processes in bone, cartilage, and the synovial membrane after PVA hemiarthroplasty in an ovine model with 6 months of follow-up.

STUDY DESIGN

Controlled laboratory study.

METHODS

A unilateral osteochondral defect (8-mm diameter × 10-mm depth) was made in the medial femoral condyle in 6 sheep. Animals were randomized to receive a PVA implant (n = 4) or to have an empty defect (n = 2) and were monitored for 6 months. Patellofemoral radiographs were obtained at monthly intervals, and quantitative computed tomography was performed at the end of the study. After death, the joints were macroscopically evaluated and scored. Osteochondral and synovial membrane histological findings were assessed using modified Osteoarthritis Research Society International (OARSI) and aseptic lymphocyte-dominated vasculitis-associated lesion (ALVAL) scoring systems. Immunohistochemistry using Iba1 was performed to evaluate activated macrophage infiltration.

RESULTS

Overall, 2 sheep with PVA implants were euthanized at 1 and 5 months because of uncontrollable pain and lameness (failed implants). Quantitative computed tomography showed that sheep with failed implants had 2.1-fold more osteolysis than those with successful implants. The sheep with failed implants had osteoarthritis with extensive glycosaminoglycan loss and cartilage fibrillation of the condyle and opposing tibial surface on histological examination. A foreign body reaction with severe chronic lymphoplasmacytic and granulomatous inflammation with giant cells was detected surrounding the implant. The synovial membrane ALVAL score was 9 of 19 and 14 of 19 in failed implants with synovial hyperplasia and lymphoplasmacytic and macrophage infiltration. In contrast, the synovial membrane in successful implants and empty defects was normal (ALVAL score = 0/19). Immunolabeling for Iba1 in failed implants confirmed extensive and dense macrophage infiltration within the condyle and synovial membrane, with the highest immunoreactive score (9/9).

CONCLUSION

PVA hydrogel implants had a 50% failure rate with uncontrollable pain, severe osteolysis, inflammation, and foreign body reactions.

CLINICAL RELEVANCE

The failure rate and pathological characteristics of the PVA implants suggest that their use should not be continued in human patients without further in vivo safety studies.