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One- and Two-Year Analysis of a Five-Year Prospective Multicenter Study Assessing Radiographic and Patient-Reported Outcomes Following Triplanar First Tarsometatarsal Arthrodesis With Early Weightbearing for Symptomatic Hallux Valgus
We report one- and 2-year results of a prospective, 5-year, multicenter study of radiographic, clinical, and patient-reported outcomes following triplanar first tarsometatarsal arthrodesis with early weightbearing. One-hundred and seventeen patients were included with a mean (95% confidence interval [CI]) follow-up time of 16.6 (15.5, 17.7) months. Mean (95% CI) time to weightbearing in a boot walker was 7.8 (6.6, 9.1) days, mean time to return to athletic shoes was 45.0 (43.5, 46.6) days, and mean time to return to unrestricted activity was 121.0 (114.5, 127.5) days. There was a significant improvement in radiographic measures with a mean corrective change of -18.0° (-19.6, -16.4) for hallux valgus angle, -8.3° (-8.9, -7.8) for intermetatarsal angle and -2.9 (-3.2, -2.7) for tibial sesamoid position at 12 months (n = 108). Additionally, there was a significant improvement in patient-reported outcomes (Visual Analog Scale, Manchester-Oxford Foot Questionnaire, and Patient-Reported Outcomes Measurement Information System) and changes were maintained at 12 and 24 months postoperatively. There was 1/117 (0.9%) reported recurrence of hallux valgus at 12 months. There were 16/117 (13.7%) subjects who experienced clinical complications of which 10/117 (8.5%) were related to hardware. Of the 7/117 (6.0%) who underwent reoperation, only 1/117 (0.9%) underwent surgery for a nonunion. The results of the interim report of this prospective, multicenter study demonstrate favorable clinical and radiographic improvement of the HV deformity, early return to weightbearing, low recurrence, and low rate of complications.
Traditional evaluation of HV involves radiographic measures using the intermetatarsal angle (IMA), hallux valgus angle (HVA), distal metatarsal articular angle and tibial sesamoid position (TSP) interpretating HV as a 2-dimensional (2D) deformity. However, HV has been shown to be multiplanar deformity characterized by metatarsus primus varus, hallux valgus and pronation of both the first metatarsal and hallux in the frontal plane (
). The sesamoid position has been shown to be a radiographic indicator of frontal plane position of both the hallux and first metatarsal. One study identified that sesamoid rotation angle on short-axis magnetic resonance imaging (MRI) was a more reproducible measure for detecting axial rotation of sesamoid or pronated first metatarsal compared to the traditional radiographic parameters of lateral sesamoid displacement or TSP (
). Additionally, frontal plane position of the first metatarsal was also found to influence the position of the tibial sesamoid. Supinatory rotational correction of the first metatarsal in patients with HV was associated with reduction of the tibial sesamoid and lateral round sign of the first metatarsal head (
). Accordingly, incomplete correction of the frontal plane component of HV deformities evidenced by incomplete sesamoid reduction and residual first metatarsal lateral round sign have been associated with increased risk for HV recurrence (
). Because the first TMT joint contributes to the most motion and sustains a high level of stress in the first ray during the gait cycle, unprotected full weightbearing after first TMT joint arthrodesis is generally not recommended until 6 weeks (
). The purpose of this study is to report the interim findings of a prospective, multicenter clinical trial on radiographic, clinical, and patient-reported outcomes after triplanar first TMT arthrodesis using biplanar plating system with early return to weightbearing in patients with symptomatic HV deformities.
Patients and Methods
This is a prospective, multicenter, 5-year clinical trial involving 7 US-based sites (2 academic centers and 5 subspecialty practices) with 13 foot and ankle surgeons who considered experienced users with at least 1 year of experience with the instrument-assisted triplanar first TMT arthrodesis system. From November 20, 2018 to April 30, 2021, a consecutive cohort of patients enrolled in this study underwent first TMT joint realignment multiplanar arthrodesis for symptomatic HV deformity. Institutional review board approval was obtained for each study site. An electronic data capture system was utilized by study site personnel to transfer study data from source records onto common electronic case report forms in a validated system. The validated system platform is a web-based secure electronic software application compliant with Good Clinical Practices data protection/data privacy and electronic record regulatory requirements. The data that is entered into the validated system is de-identified and only a unique subject number is used to identify a subject in the database. No data were transferred between institutions participating on this study. Inclusion criteria were symptomatic HV in patients between 14 and 58 years of age, intermetatarsal angles between 10.0° and 22.0°, and hallux valgus angles between 16.0° and 40.0°. Exclusion criteria consisted of prior HV surgery, body mass index (BMI) > 40 kg/m2, diabetes with HbA1c ≥ 7%, evidence of peripheral neuropathy (current clinical diagnosis of peripheral neuropathy or ≤8 of 10 points with a 5.07 Semmes-Weinstein Monofilament exam), metatarsus adductus ≥ 23°, moderate to severe osteoarthritis of the first metatarsophalangeal (MTP) joint complex evidenced by radiographic signs of joint space narrowing, peripheral osteophytosis, subchondral cyst formation and absence of intersesamoid ridge (crista) or clinically positive grind test, and current use of nicotine products.
Surgical Technique and Postoperative Protocol
The detailed surgical technique has been previously published (
). A dorsal incision was placed just medial to the extensor hallucis longus tendon to access the first TMT joint. Release of the lateral capsule and suspensory ligaments of the first MTP joint is performed. After mobilizing the first TMT joint, a fulcrum device was placed into the proximal first and second metatarsal interspace and a positioner device was applied to achieve deformity correction in all 3 anatomic planes (frontal, transverse, sagittal). Fluoroscopy confirmed correction of the HV deformity and placement of the positioner device. A cutting guide was applied to the first TMT joint, and the position was verified with fluoroscopy as shown in Fig. 1. Osteotomies were performed with cut guides for en bloc resection of the articular surface of the first metatarsal base and medial cuneiform. The joint surfaces were then fenestrated with a drill bit and a compressor instrument was used to appose the joint surfaces. All patients had a biplanar plating construct consisting of 2 low-profile 4-hole titanium plates applied to the dorsal and medial aspects of the first TMT joint. The surgeon had the option of supplementing the biplanar plating construct with an additional interfragmentary screw across the first TMT joint and an intercuneiform screw from the medial to intermediate cuneiform if intercuneiform instability was concurrently identified. Patients were bandaged and placed in a splint, cast, or boot walker on the day of surgery. At the first postoperative visit (within 3 weeks of the procedure), patients were instructed to begin weightbearing as tolerated in a boot walker. Patients were allowed to transition from the boot to an athletic shoe at 6 weeks and allowed to return to full activity at 4 months, postoperatively. Representative preoperative and postoperative radiographs are shown in Fig. 2.
Radiographic and Clinical Outcomes
Radiographic imaging was obtained preoperatively and at 6 weeks, 6 months, 12 months, and 24 months postoperatively. Imaging included weightbearing anterior-posterior (AP), lateral, and sesamoid axial radiographs in a standardized manner with individual site-technologist training. Two independent fellowship trained experienced musculoskeletal radiologists (A.C. and J.K.) reviewed the blinded radiographic data and performed all measurements using a picture archiving and communication system (AGMednet Judi//Imaging, version 7.10). The readers participated in a one-time training session on measurements on 20 cases. All measurements were performed blinded to the clinical data or other reader's measurements, and the measurements from the 2 radiologists were averaged. The IMA was defined as the angle between the longitudinal axis of the first and second metatarsals in AP radiographs. The HVA was defined as the angle between the longitudinal axis of the first metatarsal and proximal phalanx in AP radiographs. Tibial sesamoid position was graded from 1 to 7 and defined as the position of the medial sesamoid in relation to the longitudinal axis of the first metatarsal in AP radiographs (
). Sagittal plane intermetatarsal angle was defined as the angle between the longitudinal axis of the first and second metatarsals in lateral radiographs with first metatarsal dorsiflexion defined as a positive value (
). Successful correction was defined as 2 of the following 3 criteria being met 6 weeks postoperatively: IMA < 9.0°, HVA < 15.0°, and TSP as ≤ 3. Radiographic recurrence was considered to have occurred in those patients with correction if 2 of the following 3 criteria were met at least 12 months postprocedure: IMA of ≥12°, HVA ≥ 20°, and TSP ≥ 4.
Patient-reported outcomes for the operative foot were measured by visual analog scale (VAS) (
) before the procedure and at scheduled intervals during recovery. Visual analog scale was reported based on pain associated with the base of the hallux (bunion-related) preoperatively and at zero to 3 weeks, 6 weeks, 4 months, 6 months, 12, and 24 months postoperatively. Quality of life via MOxFQ and PROMIS-29 was collected preoperatively, and at 6 months, 12 months, and 24 months postoperatively. Additional endpoints included pre- and postoperative transfer pain (pain beneath second or third MTP joint) as well as clinical complications defined as infection (pain, swelling, redness worse than the anticipated postoperative course requiring treatment intervention), wound dehiscence (surgical incision failing to heal during the anticipated postoperative course requiring treatment intervention), pain at implant site, neurovascular insults, implant complications, and nonunion (clinical pain at fusion site and at least one of the following: lucency at first TMT joint, hardware failure and/or loss of correction). Additionally, data were collected with respect to time (days) to return to work (or normal household activities if nonworking) and time to return to full work, while noting work classification (sedentary, light work, medium work, heavy work, very heavy work).
These interim results were limited to patients completing at least 12 months of follow-up. All statistical analyses were performed using SAS software, version 9.4 (SAS Institute Inc., Cary, NC). Continuous variables were summarized using means and 95% confidence intervals (CIs). Categorical variables were summarized using frequencies and percentages. Inferential statistics were performed on changes from baseline using a paired t-test. Confidence intervals which did not contain zero were regarded as significant at the 0.05 level.
A total of 183 patients were enrolled in the clinical trial. Ten patients were identified as screening failures, ineligible for the study and dropped from the study protocol. A final 173 eligible patients underwent first TMT joint realignment multiplanar arthrodesis for symptomatic HV deformity. At time of data cut-off for the interim analysis, there were 117 patients with at least 12 months of follow-up of which 40 patients had at least 24 months of follow-up. Mean time of follow-up was 16.6 (range 11.2-29.0) months. At the time of the analysis, 9 patients dropped out of the trial (3 moved out of state, 6 were lost to follow-up during the COVID-19 pandemic). Patient demographic information is summarized in Table 1. Adjunctive procedures that were concurrently performed are shown in Table 2. Patients underwent early return to weightbearing, with a mean number of days postprocedure to boot walker, to athletic shoes, and to unrestricted activity of 7.8 (95% CI: 6.6, 9.1), 45.0 (95% CI: 43.5, 46.6), and 121.0 (95% CI: 114.5, 127.5), respectively, shown in Table 3. The patients returned to work within an average of 25.2 (95% CI: 19.3, 31.1) days and to full work within an average of 54.2 (95% CI: 45.8, 62.5) days.
Table 1Patient demographic information
Age (years), mean (95% CI)
40.6 (38.5, 42.7)
Sex, n (%)
BMI, mean (95% CI)
26.1 (25.2, 26.9)
Foot, n (%)
Diabetes, n (%)
Labor class, n (%)
Very heavy work
Abbreviations: CI, confidence interval; BMI, body mass index.
Radiographic measurements were taken at baseline, 6 weeks, 6 months, 12 months, and 24 months shown in Table 4 and Fig. 3. A statistically significant improvement from baseline in radiographic measures was observed at 6 weeks postprocedure, as evidenced by confidence intervals that do not contain zero, and statistically significant improvements were maintained at 24 months as shown in Table 5. Of the 115 patients with 6-week radiographic data, 114 (99.1%) met the definition of correction. Of those corrected, 1 patient (0.9%) exhibited recurrence at 12 months. A statistically significant improvement from baseline in patient-reported outcomes is shown in Table 6 and Fig. 4. A statistically significant improvement in all PROMIS domains was also observed at 6 and 24 months postprocedure, and all but one PROMIS domain demonstrated a statistically significant improvement over baseline at 12 months as shown in Table 7. Radiographic measures and patient-reported outcomes collected after the 6-month follow-up demonstrated continued improvement up to 24 months. Of the 89 patients without transfer pain at baseline, 2 (2.2%) reported transfer pain postprocedure. Of the 17 patients with baseline transfer pain, fifteen (88.2%) reported no transfer pain postprocedure. There were 16 (13.7%) patients who experienced clinical complications with 6 (5.1%) undergoing reoperation for removal of hardware (4 (66.7%) due to pain; 2 (33.3%) per patient request), 4 (3.4%) cases of hardware breakage that did not necessitate hardware removal, and 1 (0.9%) patient who exhibited nonunion requiring reoperation seen in Table 8.
Table 4Radiographic measures at times: baseline, 6 week, 6 month, 12 months, 24 months, mean (95% CI)
Did not require reoperation. Patients are considered healed per protocol definition. Hardware status by patient: 1 broken screw; 1 broken dorsal plate and 2 broken screws; 1 broken medial plate and 2 broken screws; broken medial plate.
Did not require reoperation. Patients are considered healed per protocol definition. Hardware status by patient: 1 broken screw; 1 broken dorsal plate and 2 broken screws; 1 broken medial plate and 2 broken screws; broken medial plate.
This interim analysis of a prospective, 5-year, multicenter study assessing radiographic and patient-reported outcomes of instrument-guided triplanar HV correction with first TMT realignment arthrodesis demonstrates favorable clinical results with anatomic correction and early return to weightbearing. Statistically significant improvements in radiographic measurements over baseline were observed at 6 weeks and maintained at 12 and 24 months. One (0.9%) patient experienced recurrence at 12 months. Shibuya et al (
) reported that incomplete reduction of HV deformities with residual HVA of 15°, IMA of 8°, and TSP ≥ 5 at a mean follow-up of 3.1 months had 10-fold increased odds for HV recurrence. In this study, we report a mean (95% CI) of 8.6° (7.7, 9.5) for HVA, 4.0° (3.6, 4.4) for IMA, and 1.6 (1.4, 1.7) for TSP at the 6-week follow-up visit.
Full weightbearing without protective devices is often not recommended until 6 weeks for first TMT joint fusions (
). We used a biplanar plating construct with 2 low-profile 4-hole titanium plates in all cases of first TMT arthrodesis. The mean time to weightbearing in a short leg boot walker was 7.8 days. Mean time to return to shoes and unrestricted activity was 45.0 and 121.0 days, respectively. We reported a nonunion rate of less than 1% in this interim analysis. Previous studies evaluating early weightbearing within 2 weeks following Lapidus procedure reported nonunion rates ranging between 8.0% and 9.5% (
Patient-reported outcomes have been used as a functional measure of physical and mental function after musculoskeletal surgery and have been used to measure health-related quality of life improvement after HV surgery. Patients demonstrated decrease in pain with VAS and improvements in the MOxFQ domains of Walking/Standing, Pain, and Social Interaction. PROMIS uses computer-adaptive technology to collect data in domains of physical function, pain, and depression and has shown reliability and responsiveness with reporting outcomes in foot and ankle surgery (
). The interim results presented in this study indicate favorable patient response with triplanar correction at 6, 12, and 24 months with statistically significant reduction of pain and depression, and improvement of function.
Frontal plane component of HV deformity was discussed by Okuda et al (
) demonstrated that the lateral position of the sesamoid apparatus in HV deformities was associated with first metatarsal pronation/eversion not solely lateral translation. Additionally, in a series of 35 patients who underwent HV correction with first TMT correction, Dayton et al (
) demonstrated that supinatory correction of the first metatarsal was associated with reduction of the TSP. Previous retrospective studies utilizing triplanar correction methods treating HV deformities have reported favorable outcomes with radiographic reduction, low recurrence, and low nonunion rates (
). The findings from this prospective study are consistent with these previous reports.
There are several notable findings in this observational clinical trial. The longitudinal data demonstrates maintenance of the IMA, HV, TSP of the HV correction from the sixth week through 24 months. While this data may support the role of triplanar correction and biplanar fixation methods with this maintenance of HV correction, we recognize that this association would be better evaluated with a comparative trial design. Second, fusion rates were comparable to the first TMT healing rates of previously published reports with early weightbearing (
). Patients in this study were allowed protected weightbearing in a boot walker within a mean of 7.8 days and exhibited a nonunion rate of less than 1% with biplanar plate fixation method. Third, TSP position correction, which has been reported as risk factor for HV recurrence, was consistently corrected to a mean of 1.7 with only undergoing a release of the lateral capsule and suspensory ligaments. While this data may suggest a role for TSP and HV recurrence, analysis with further time points will be help to support this relationship. Fourth, we reported minimal elevation of the first metatarsal in our series. The mean sagittal plane position of the first metatarsal was 0.9 degrees. Maintaining sagittal position and length of the first metatarsal supports first MTP range of motion and reestablishes the anatomy of the metatarsal parabola preventing transfer metatarsalgia. Although mean shortening of the first metatarsal was not recorded in this study, Hatch et al (
) previously reported a mean 2.4 mm of shortening and -0.2 degrees change in sagittal alignment using this instrument-assisted technique. Only 1 (1.4%) patient underwent lesser metatarsal osteotomies as part of the index procedure. Clinically, 5.1% of patients reported lesser metatarsal pain postprocedure.
We recognize several limitations of this study. This is an interim report of up to 24 months postoperative follow-up on a 5-year prospective study. Participating patients were being continuously enrolled and patients will be followed for up to 60 months for radiographic measures, recurrence, healing, complications, and patient-reported outcomes. We used standard radiographic measurements which have known degrees of error in both radiographic technique and angular measures. To control these variables, training was provided to all study sites regarding image acquisition and standard method for interpretation. Interim quality surveillance audits were also performed. The measurements were performed by 2 independent fellowship-trained experienced musculoskeletal radiologists. We recognize that there is a potential selection bias of patients in our study by excluding subjects above the age of 59 years which represents more than a third of the population afflicted with HV deformity. Additionally, some of our data was collected during the time of the COVID-19 pandemic which may have affected the return to work and return to full work reporting. Additionally, this is a single-arm study without a control or comparison group, therefore direct comparisons on time to weightbearing, fixation constructs, and complication rates related to this specific technique are based on historic results of other procedures. Last, we recognize that the financial disclosures and conflicts of interest whether actual or potential are important considerations in identifying any source of influence or bias in a clinical trial. Several of authors were involved with the design of the instrumentation and implants in consultation with bioengineers who were funded by the sponsors of this study. Other authors served as consultants during the design and implementation of the study (A.C., M.J.D., P.D.D., W.J.D, D.C.F., D.J.H., J.K., J.P.M., A.R., R.D.S., and R.P.T.). One author served as a consultant for statistical and data analytics support (D.A.K.). All study sites received predetermined financial support for research-related activities. For example, the institutions of the following authors received institutional research support for this study (A.C., G.T.L., K.M.R., M.V.P., and D.K.W.). No study investigator received any direct compensation for participation in this study. Some of the authors receive royalties for intellectual property from the sponsoring company (P.D.D., D.J.H., J.P.M., and R.D.S.). Other authors have open market stock ownership of the sponsoring company (M.J.D., P.D.D, W.J.D, D.J.H., J.P.M., and R.D.S.). Financial disclosures are publicly available on the Centers for Medicare and Medicaid Services website at https://www.cms.gov/openpayments.
In conclusion, this is the first report on an interim analysis of a 5-year prospective, multicenter, clinical trial using an instrumentation-assisted triplanar correction system for the treatment of symptomatic HV deformities. We report statistically significant improvements in radiographic correction, low recurrence of deformity, and early return to activity with low complication rates up to a 24-month postoperative review. Additionally, we report statistical improvements in patients' health-related quality of life up to a 24-month follow-up period.
Prevalence of hallux valgus in the general population: a systematic review and meta-analysis.
Financial Disclosure: G.T. Liu is a consultant for Orthofix and Gramercy Extremity Orthopedics. A. Chhabra is a consultant for Image Biopsy Labs and Icon Medical. K.M. Raspovic is a consultant for Orthofix. D.K. Wukich is a consultant for Orthofix and Wright Medical Technology and receives royalties from Arthrex.
Conflict of Interest: A. Chhabra, W.J. Duke, D.C. Farber, D.J. Hatch, J.P. McAleer, M.J. Dayton, P.D. Dayton, A. Raissi, R.D. Santrock, R.P. Taylor and J. Koay are consultants for Treace Medical Concepts, Inc. W.J. Duke, D.J. Hatch, J.P. McAleer, M.J. Dayton, P.D. Dayton and R.D. Santrock have open market stock ownership of Treace Medical Concepts, Inc. P.D. Dayton, D.J. Hatch, J.P. McAleer and R.D. Santrock receive royalties for intellectual property from the Treace Medical Concepts, Inc.