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Baumhauer et al4 presented the first study evaluating the
PVA hydrogel implant following a prospective, randomized, noninferiority study comparing the implant with first
MTP arthrodesis. These authors reported significant but
similar improvements in Foot and Ankle Ability Measure
(FAAM) Sports and Activities of Daily Living scores, as
well as the visual analog scale (VAS) between the two
cohorts at 12 and 24 months of follow-up. Recent studies
have presented less promising results with regard to the
PVA implant at short-term follow-up.1,5
Cassinelli et al5 presented the first study evaluating the
PVA implant following FDA clinical trials, reporting
Physical Function and Pain Interference PROMIS outcomes
as well as patient satisfaction measures in a cohort of 60
patients (64 implants). These authors did not include baseline patient-reported outcomes assessment or comparison
with a control group. The authors reported an average postoperative Physical Function score of 42 (n = 42) and Pain
Interference score of 60 (n = 40).5 The higher Physical
Function and lower Pain Interference scores observed in
our PVA cohort may reflect the differences in surgical technique, as patients in our study underwent additional concurrent limited cheilectomy and Moberg osteotomy.
For patients undergoing PVA implantation in the initial
clinical trial, Baumhauer et al4 reported that 14 out of 152
PVA implant patients (9.2%) required a subsequent conversion to arthrodesis at an average of 1 year postoperatively.
Cassinelli et al5 reported a higher incidence of PVA implant
revision, with 13 out of 64 patients (20%) in their cohort
undergoing revision surgery at an average of 12.6 months
postoperatively, though they report a comparable rate of
conversion to arthrodesis (5 of 64 implants [8%]) at an
average of 16.4 months. In their cohort of CM patients,
O'Malley et al19 reported that 4 out of 81 patients (4.9%)
required conversion to arthrodesis, 1 at 1 year, 2 at 3 years,
and 1 at 7 years postoperatively. In the first 1 to 2 years
postoperatively, we observed only 4 total revisions, 3 out
of 60 (5%) in the PVACM group and 1 out of 73 (1.4%) in
the CM group. At 1- to 2-year follow-up, these rates of
revision are substantially lower than those that have been
reported previously following PVA implantation or cheilectomy with Moberg alone. Despite relatively low rates of
revision in our cohort, about 10% to 15% of patients
reported persistent postoperative pain, though a majority of
these cases resolved over time or with conservative management, including injection, orthotics, and shockwave
therapy. Several PVACM patients presenting with persistent
postoperative pain underwent MRI, which demonstrated
persistent edema in the first metatarsal head. The patterns of
edema observed were consistent with those described in a
recent study evaluating symptomatic PVA implants on
MRI.1
There are several limitations of the present study. Though
previous studies have evaluated outcomes with respect to

Foot & Ankle International 41(9)
severity or grade of hallux rigidus, we did not stratify our
cohorts based on preoperative grade, though the indication
for operative management with a joint-preserving procedure at our institution typically includes grade II or III
hallux rigidus based on the Coughlin scale.6 Further,
Baumhauer et al3 have previously shown that active dorsiflexion range of motion and baseline VAS pain scores did
not correlate with the Coughlin hallux rigidus grade and did
not predict the success or failure of either PVA hydrogel
implantation or first MTP arthrodesis. Their results suggest
that clinical symptoms should be used to guide treatment as
opposed to grading systems that have not been validated.
The primary difference between our PVA implant
cohort and those described in the existing literature is that
we routinely added a cheilectomy and Moberg osteotomy
in conjunction with PVA implantation in our study cohort.
The present study included all patients undergoing cheilectomy with Moberg at our institution, with or without
use of the PVA implant. Therefore, this criterion for inclusion in our study may not allow for direct comparisons to
be made with results from other PVA implant cohorts represented in the existing literature due to the difference in
surgical technique. Nonetheless, our study represents the
first to compare outcomes for patients undergoing PVA
implantation with limited cheilectomy and Moberg osteotomy versus a standard joint-preserving procedure for
hallux rigidus.
Because cheilectomy with Moberg osteotomy was the
primary procedure performed at our institution to address
hallux rigidus before the PVA implant was FDA approved,
CM has been performed for a longer duration of time, and
therefore clinical follow-up for the CM group is significantly longer, 36.6 months on average compared with 27.7
months for the PVACM group. While there is a significant
difference in follow-up times, we believe a meaningful
comparison can be made, as both cohorts had a minimum of
2 years of clinical follow-up on average. A longer follow-up
in both cohorts would be optimal, as 1 study evaluating
midterm outcomes using the PVA implant reported that pain
and symptom relief observed in the first 2 years postoperatively was maintained at 5 years, though 9 out of 119
patients (7.6%) underwent conversion to arthrodesis
between 2 and 5 years.7
In order to better distinguish the impact of the PVA
implant, we excluded patients who underwent cheilectomy
only with PVA implant or first MTP resurfacing with PVA
implant alone, allowing for comparison of patients treated
only with cheilectomy and Moberg, with or without the PVA
implant. In order to ensure that sufficient intact cortical rim
remained for the implant in PVACM procedures, we performed a limited cheilectomy involving approximately 10%
of the metatarsal head for PVACM cases, compared with up
to 30% in the CM group, which is a limitation of our comparison. As previously mentioned, we acknowledge that our
Foot & Ankle International - September 2020

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