Journal of Foot and Ankle Surgery (Asia-Pacific)
Volume 10 | Issue 3 | Year 2023

Patient Reported Outcome Measure for Cartiva Synthetic Cartilage Replacement in Advanced Degenerative Disease of the Hallux Metatarsophalangeal Joint: A Single Surgeon Series

Josh Rutnagur1, Perrico Nunag2https://orcid.org/0000-0002-8991-3943, Mohammed T Bashir3

1Department of Orthopaedics, NHS Grampian, Aberdeen, United Kingdom

2Department of Orthopaedics, Raigmore Hospital, Inverness, United Kingdom

3Department of Orthopaedics, University of Aberdeen, Aberdeen, United Kingdom

Corresponding Author: Josh Rutnagur, Department of Orthopaedics, NHS Grampian, Aberdeen, United Kingdom, Phone: +4407428550713, e-mail: rutnagurj@hotmail.co.uk

Received on: 19 November 2022; Accepted on: 10 December 2022; Published on: 07 July 2023


Background: Cartiva® synthetic cartilage implant (SCI) was introduced in our department in 2016 as an alternative treatment for advanced degenerative disease of the hallux metatarsophalangeal joint (MTPJ) requiring fusion, but we would rather prefer to maintain joint movement.

Method: A prospective audit was commenced to monitor clinical results limiting selection criteria to young patients with advanced disease with no hallux deformity and no inflammatory arthritis. Outcome measures include patient-reported outcomes using the Manchester-Oxford Foot Questionnaire (MOXFQ) and total range of movement.

Result: Between 2016 and 2019, we performed Cartiva® SCI in 19 toes in 16 patients. The 13 toes were grade IV, and six were grade III. Outcome data were collected at 3, 6, 12, and 24 months. We have complete follow-up data for 19 of 19 cases at 3 and 6 months, 14 of 19 at 1 year, and seven of 19 at 24 months.

Results show significant improvement in MOXFQ scores compared to preoperative (pre-op) scores, with peak improvement at 6 months, followed by a slight decline but stayed significantly better compared to pre-op scores. This was observed in all components of the MOXFQ except for social interaction, which showed continuous improvement for up to 2 years.

The total range of movement showed steady improvement from a mean pre-op baseline of 31–55° at 3 months (p ≤ 0.001), 63° at 6 months (p 0.00), 59° at 12 months (p 0.003), and 80° at 24 months (p 0.043).

Two patients required further procedures for continuing pain and stiffness. One was converted to fusion after 2 years. One patient had a manipulation and steroid injection.

One patient developed a “squeegee” sensation when walking and moving the toe, which spontaneously resolved after 6 months.

Conclusion: Our results indicate good short-term results in 17 of 19 patients with Cartiva® SCI based on patient-reported outcomes and the total range of joint movement.

Level of evidence: IV–case series.

How to cite this article: Rutnagur J, Nunag P, Bashir MT. Patient Reported Outcome Measure for Cartiva Synthetic Cartilage Replacement in Advanced Degenerative Disease of the Hallux Metatarsophalangeal Joint: A Single Surgeon Series. J Foot Ankle Surg (Asia-Pacific) 2023;10(3):151–155.

Source of support: Nil

Conflict of interest: None

Keywords: Cartiva, Hallux rigidus, Interposition arthroplasty, Manchester-Oxford Foot Questionnaire, Patient reported outcome measures


Hallux rigidus is a common degenerative condition which affects approximately 2.5% of patients over 50 years. It is a progressive disorder and is associated with pain and loss of joint movement.

Management is dependent on the severity of clinical symptoms and radiographic appearance. In advanced stages, operative management becomes necessary for pain relief. Fusion of the joint remains the most popular operative option. It is reliable in relieving pain but requires the sacrifice of joint movement, which is not acceptable for many patients.

Historical operative options have included resection arthroplasty1 and Moberg osteotomy.2

In recent decades, joint replacement-type surgeries have been developed with varying results. These include Moje joint replacement,3 Townley metallic hemiarthroplasty,4 hemiCAP hemiarthroplasty,5 and silicon replacement.6

The Cartiva SCI is promoted as a joint-preserving alternative to fusion and is equally effective in relieving pain.7 SCI comprises an organic hydrogel polymer composed of polyvinyl alcohol and saline. It has a high-water content, and its elastic and compressive mechanical properties are similar to articular cartilage. It is a cylindrical implant and is placed into the metatarsal head via press-fit implantation (Fig. 1).8

Fig. 1: Cartiva® implant; Hofheinz E. Cartiva first-op procedure with SCI. Orthopedics this week, RRY Publications, July 2017. (access at: https://ryortho.com/breaking/cartiva-first-op-procedure-with-synthetic-cartilage-implant)

The operative technique is simple, requires minimal instrumentation and leads to minimal bone loss; thus, the postoperative (post-op) recovery is faster than fusion.8 Owing to the minimal bone loss during the primary procedure, salvaging a failed SCI with fusion has been shown to produce similar outcomes to primary arthrodesis.9

Results from other series show positive midterm results. SCI has demonstrated high survivorship at 28 and 5 years10 and has produced similar pain relief and functional outcomes to fusion with a preserved range of motion (ROM).10,11 However, there remains a paucity of studies evaluating SCI, with most publications in the field derived from a single randomized controlled trial.8

We introduced Cartiva® SCI in our department in 2016; hence a mandatory audit was undertaken as a requirement for clinical governance when introducing a new procedure.


This study aims to assess the clinical outcome of patients with advanced hallux MTPJ osteoarthritis treated with Cartiva® SCI based on patient-reported outcomes measure scores and total ROM of the joint.


Patient Population and Data Collection

Data were prospectively recorded for all patients who underwent SCI for advanced hallux MTPJ arthritis performed by a single surgeon at a district general hospital from 2016 to 2019. The procedure was selectively offered to young patients with an advanced disease which required fusion but would rather preserve joint movement. Patients with significant hallux deformity and inflammatory arthritis were not offered this treatment.

Disease severity was assessed clinically and radiographically by the senior author and classified using the Coughlin and Shurnas (C&S) grading system.

The primary outcome was the MOXFQ score. The MOXFQ is a validated patient-reported questionnaire which assesses outcomes following foot and ankle corrective surgery.12 It comprises 16 items which examine three domains: walking/standing, pain, and social interaction. Each section is scored from 0 to 4, indicating increasing severity. Scores are summed, generating total scores for each domain and for the entire questionnaire. Total scores are then converted to metric scores for increased sensitivity, as per user instructions.

The secondary outcome was the ROM of the hallux. This was assessed by the senior author using a handheld goniometer. Dorsiflexion was assigned a (+) value, and plantar flexion a (−) value. The range of movement was calculated as the difference between dorsiflexion and plantarflexion.

Outcome data were recorded pre-op and then at 3, 6, 12, and 24 months post-op. Ethical approval was not applicable for this case series, and each patient provided informed consent for patient reported outcome measures to be collected.

Operative Technique

The procedure was performed under general or spinal anesthetic with the patient supine. Prophylactic antibiotics were given, and a thigh tourniquet was used. The MTPJ was approached dorsally. The extensor hallucis tendon was retracted, and peripheral osteophytes were removed. The collateral ligaments were preserved.

The SCI kit comes with a metallic placer, a 2 mm guidewire, a cannulated reamer, and an introducer. The placer is either 8 or 10 mm in diameter and corresponds to the size of the implant chosen. The 10 mm implant was used in all cases in this series.

The placer was used to guide wire insertion, ensuring perpendicular placement to the joint surface. The wire was applied centrally but adjusted to cover the worn area with at least a 2 mm margin of bone around the rim. Reaming over the guidewire was done to create the cavity in the metatarsal head, making sure not to rim all the way but leave a 2 mm gap between the surface and reamer stopper.

The implant was inserted and pressed into the cavity using the introducer, leaving it 2 mm proud. The joint was reduced, and smooth gliding over the surfaces was confirmed.

The capsule was repaired without tension with a no. 2.0 vicryl suture and the skin were closed using interrupted nylon sutures. Wound dressing was applied, and the foot was strapped with wool and crepe.

Postoperative (post-op) Care

Patients were allowed to full weight-bear as tolerated and were advised to elevate their feet. The foot strap was removed after 24–48 hours. Active movement of the joint was encouraged as soon as pain allowed. ROM exercises were performed by the patients themselves, and no formal physiotherapy was employed. A single post-op X-ray was taken at the first follow-up appointment, at which time the sutures were also removed.


Manchester-Oxford Foot Questionnaire (MOXFQ) scores were analyzed as total scores and as three subcategories: walking/standing, pain, and social interaction. Raw scores were converted to metric scores for each of the analyzes to increase sensitivity as instructed by the user manual. MOXFQ scores pre-op were compared with those at 3, 6, 12, and 24 months and the distribution of differences were analyzed using the Wilcoxon signed-rank test.

Range of motion (ROM) was calculated by summing values for dorsiflexion and plantarflexion. Pre-op ROM was compared with ROM at follow-up, and the mean difference was analyzed using a paired t-test. Limited data were available for ROM at 24 months, and Wilcoxon signed-rank test was utilized for this analysis.

A p-value of <0.05 was considered to be statistically significant. Data were stored using Microsoft Excel, and Statistical Package for the Social Sciences version 25.0 for Windows was used for analysis.


A total of 19 SCI operations were conducted over the study period, nine right toes and 10 left toes. These were from 16 patients, 11 females and five males, who had a mean age of 53 years (range 37– 64). A total of 13 toes were classified as (C&S) grade IV, and six were classed as grade III. See Figure 2 for a typical pre-op and post-op radiograph.

Fig. 2: Preoperative (pre-op) and post-op radiographs demonstrating increased joint space. The cavity in the metatarsal head housing the implant is also visible on plain films

Manchester Oxford Foot Questionnaire (MOXFQ) Scores

Complete MOXFQ data were collected at 3- and 6-months follow-up for all patients. At 12 months follow-up, complete data were collected for 14 of 19 cases, and there were complete data for seven patients at 24 months post-op. Median metric scores for the MOXFQ total and subscores at baseline and follow-up are displayed in Table 1.

Table 1: Median MOXFQ total score and subgroup scores pre-op and at follow-up. p-values from Wilcoxon signed-rank test
Total score p-value Walking/standing p-value Pain p-value Social interaction p-value
Pre-op 53.12 - 53.57 - 65 - 43.75 -
3 months (n = 19) 32.81 0.004 39.29 0.035 30 0.001 18.75 <0.01
6 months (n = 19) 17.19 <0.001 17.86 0.001 20 <0.001 12.5 <0.01
12 months (n = 14) 17.97 0.006 10.71 0.01 30 0.02 12.5 0.002
24 months (n = 7) 29.69 0.018 28.57 0.018 35 0.018 0 0.018

The median total MOXFQ score for each interval is displayed in Figure 3. The median metric MOXFQ score pre-op for the series was 53.13. 3 months post-op, this improved to 32.81, and this further improved to 17.19 at 6 months. The median metric total MOXFQ score at 12 months was 17.97 for the available patients, and this was 29.69 at 24 months. Improvements in scores were statistically significant at all points of follow-up when compared with pre-op scores.

Fig. 3: Median total MOXFQ score

Walking/standing scores are graphically displayed in Figure 4. The median metric score improved from 53.57 pre-op to 39.29 at 3-month follow-up. This improved again at 6 months to 17.86 and again to 10.71 at 12 months. The scores appeared to increase at 24 months, with a median metric score of 28.57. Significant improvements in scores were seen at all points of follow-up when compared with those at baseline.

Fig. 4: Median walking/standing score

Pain data are displayed in Figure 5. The median score improved from 65 pre-op to 30 at 3 months. This again improved to 20 at 6 months. Scores increased to 30 at 12 months and 35 at 24 months. The pain had significantly improved at all points of follow-up when compared with the baseline score.

Fig. 5: Median pain score

Social interaction score data are demonstrated in Figure 6, with a median score of 43.75 pre-op. This improved to 18.75 at 3 months and to 12.50 at 6 months. The median metric score was 12.5 at 12 months, and the median score was 0.00 at 24 months of follow-up. Again, significant improvements were seen at all points of follow-up when compared with baseline scores.

Fig. 6: Median social interaction score

Range of Motion (ROM)

Range of motion (ROM) data for the series are reported in Table 2. Complete data were collected for all 19 toes pre-op and at 3 months post-op. Data were collected for 18 of 19 toes at 6 months, 13 of 19 at 12 months, and five of 19 toes at 24 months.

Table 2: Range of movement in degrees pre-op and at each point of follow up. p-values reported from paired t-tests comparing total ROM to pre-op except a which is from a Wilcoxon signed-rank test
Mean Mean ROM p-value
Pre-op Dorsiflexion 20.26 31.84 -
Plantarflexion 11.58
3 months (n = 19) Dorsiflexion 39.47 55.00 <0.001
Plantarflexion 15.53
6 months (n = 18) Dorsiflexion 44.41 63.24 <0.001
Plantarflexion 18.8
12 months (n = 13) Dorsiflexion 40.00 59.29 0.003
Plantarflexion 19.29
24 months (n = 8) Dorsiflexion 45.00 80.00* 0.043
Plantarflexion 30.00

*Indicates median value

The mean ROM pre-op was 31.84°. This improved to 55.00 and further to 63.24° at 3- and 6-month follow-up, respectively. This dropped slightly to 59.29° at 12 months. ROM had significantly improved at all points of follow-up when compared with baseline. Median 24-month ROM was 80.00, and this was marginally significantly higher than the baseline (p = 0.043).

These data are displayed graphically in Figure 7, except for ROM at 24 months.

Fig. 7: Mean dorsiflexion and plantarflexion in degrees. The area under the curves represents total arc of motion


Two patients had persistent pain and stiffness after SCI. One patient responded well to cortisone injections and manipulation under anesthesia and remained under review at the time of writing. The second patient underwent first MTPJ fusion. This decision was made 24 months after the primary operation, at which time the patient had a metric MOXFQ score of 71.9. Of note, this patient had two failed temporomandibular joint replacement surgeries prior to SCI, which left her with an extremely limited mouth opening. She is suspected of having undiagnosed inflammatory arthritis, and in hindsight, the authors feel that this may have been a case of poor patient selection.

Although not considered a significant complication, it is worth mentioning that one patient reported a faint sensation resembling rubber against the mirror surface when moving her toe. This “squeegee” sensation, which was appreciable on clinical examination, was not associated with pain or any other symptoms and had resolved spontaneously at the 6-month review. Thereafter, the patient went on to undergo SCI replacement on the other big toe. This issue was not highlighted in the reviewed literature, and it is possible that this was a result of a proud implant, which settled with time.


Our audit shows good outcomes of SCI replacement for advanced hallux rigidus in a young series of patients without hallux deformity. Patients had significant improvements in self-reported pain, mobility and social function. Our series also indicate preservation and improvement of ROM up to 2 years post-op.

The findings of this audit are consistent with other series in the literature, demonstrating positive short-term outcomes. Randomized controlled trial data for 106 patients demonstrated significant improvements in pain scores and function up to 5 years post-op and reported high levels of patient satisfaction.10

Our data demonstrate peak results at 6 months followed by a declining trend in the MOXFQ scores except for social interaction, although all scores remain significantly better than pre-op scores all throughout the study period. Other studies showed consistent improvements in outcomes up to 5 years of follow-up.11 All patients in our series had a routine follow-up of 6 months, and data were collected after this period opportunistically, with data available for 14 of 19 and seven of 19 patients at 12 and 24 months, respectively. To explain the trend, we speculate that patients returning after 6 months are the ones who have a relatively poorer outcome.

Cartiva® SCI is shown to have survivability similar to arthrodesis, with around 10% of cases requiring a secondary procedure.8 The current series shows a revision rate of 5% (one of 19 cases). One series reports that nearly a third of their cases require manipulation under anesthesia for stiffness.13 Only one patient (5%) in the current series required manipulation. The patient remains under review, and it is anticipated he will require fusion in the near future.

Owing to the minimal dissection and bone stock preservation with SCI, the authors found that, in the singular case that needed revision, conversion to arthrodesis was straightforward. This is consistent with reports from other studies.9 However, in the case of the current series, the implant cavity needed filling with a small number of bone chips during the fusion procedure.

This study had several limitations. The follow-up period was limited by local policy, and hence long-term symptom change and integrity of the implant could not be assessed. This also resulted in little data available at 12 and 24 months. Additionally, the small sample size and selection of young patients limit the generalizability of these results.


Cartiva® SCI replacement has a good short-term patient-reported outcome. It relieves pain, and it preserves and improves joint movement at the same time.

It is a sound alternative to fusion for young patients with advanced hallux MTPJ osteoarthritis and no hallux deformity.

However, a long-term study is required to determine if the currently favorable outcomes are maintained and to determine the long-term survivorship of the implant.

Brief Summary

What is already known:

  • Cartiva® provides similar pain relief to the first MTPJ fusion in advanced hallux rigidus without deformity.

  • Good short-term to mid-term results.

  • The operative method is simple, with shorter post-op recovery compared to fusion.

What this study adds:

  • Our study provided pre-op and post-op ROM; most studies only report post-op movement.

  • The procedure does not require a specialized setup and can be done in a small District General Hospital (DGH) setting.

  • Revision to fusion, although technically easy, requires the use of bone chips to fill up the implant cavity.


Josh Rutnagur https://orcid.org/0000-0002-8991-3943


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