Minimally Invasive Chevron-Akin for Correction of Moderate and Severe Hallux Valgus Deformities: Clinical and Radiologic Outcomes With a Minimum 2-Year Follow-up

Utilisation of the minimally invasive chevron akin (mica) osteotomy for severe hallux valgus: a systematic review

BACKGROUND AND AIM

Hallux valgus is the most common forefoot disease that can cause pain and be disabling for the patient. Many surgical procedures have been described to correct this deformity; over the last years, the minimally invasive Chevron and Akin osteotomies (MICA) technique has become very popular. The aim of this review was to assess if MICA technique is a reliable procedure for treating severe hallux valgus.

METHODS

A systematic review was performed according to the Preferred Reporting Items for systematic Reviews and Meta-Analysis (PRISMA) guidelines. The keywords were searched in PubMed Medline and Cochrane library. To minimise the number of missed studies, no filters were applied to the search strategy. To be considered for this review, the articles needed to comply with the following inclusion criteria: Minimally invasive Chevron and Akin osteotomy (MICA) for severe hallux valgus (HVA > 40°, IMA > 16°), patient age over 18 years and minimum follow-up of 6 months.

RESULTS

Following the PRISMA flow chart 7 studies met the inclusion criteria and were taken into consideration in the review. We reached a population of 582 patients for a total of 676 feet. Males and females were 64 and 518, respectively. The mean age was 54.15 ± 8.25. The mean follow-up was 23.74 ± 9.60 months. All the studies reported an improvement in clinical results, in terms of function and quality of life. Radiological variables, mostly IMA and HVA, assessed pre- and postoperatively showed significant improvement in all studies included.

CONCLUSIONS

Despite the limited number of published studies in the literature, the available evidence reveals good clinical outcomes and high levels of patient satisfaction. Percutaneous surgery for severe hallux valgus can achieve great deformity correction with reasonable rates of residual deformity. Patient satisfaction and quality of life following third-generation MICA surgery is very high.

Minimally Invasive Forefoot Surgeries Using the Shannon Burr: A Comprehensive Review

Since the early 2000s, minimally invasive forefoot surgery (MIS), particularly hallux valgus correction, has significantly advanced with the introduction of the Shannon burr. However, despite numerous relevant studies being published, no comprehensive review articles have summarized MIS for various forefoot conditions. Therefore, in this comprehensive review, we examined the relevant studies about the application of MIS (excluding arthroscopy and endoscopy) for various forefoot conditions. Additionally, we discuss the essential considerations for achieving favorable surgical outcomes and preventing complications associated with each technique. We analyzed the characteristics of each surgical procedure and identified areas for future focus. Effective surgical treatment not only requires MIS, but also the appropriate selection of patients based on suitable indications and executing procedures within the surgeon's capabilities. We hope that this review will help readers to enhance their expertise in this field.

Changes in Foot Width in Minimally Invasive Bunionectomy

BACKGROUND

Minimally invasive bunionectomy (MISB) has emerged as a popular approach to treat symptomatic hallux valgus deformity. Although previous studies focused on distal foot width changes postsurgery, this research introduces a novel midshaft measurement to evaluate proximal transverse midfoot width, aiming for a comprehensive understanding of foot changes post-MISB.

METHODS

A retrospective review of 44 HV patients from an institutional registry was conducted. Demographic data, surgical details, radiographs, and foot width measurements were collected. Changes in hallux valgus angle (HVA) and intermetatarsal angle (IMA) were also measured.

RESULTS

Intraclass correlation coefficients (ICCs) demonstrated good to excellent interobserver reliability (all ICCs > 0.70) for all measurements. MISB resulted in a consistent reduction in distal foot width (P < .001). These reductions correlated with changes in HVA and IMA, suggesting that the extent of deformity correction influenced distal foot width: distal bone width decreased an average of 8 mm, P < .001). However, midshaft bony width increased an average of 4 mm, P < .001). Changes in midshaft foot width showed no correlation with HVA or IMA alterations.

CONCLUSION

We found in this cohort of 44 patients that MISB for HV leads to an expected decrease in distal bony foot width but, on average, an increase in midshaft foot width.

Outcome comparison of minimally invasive proximal and distal chevron Akin osteotomies in patients with severe hallux valgus deformity: A randomized prospective study

PURPOSE

To date, the surgical treatment of severe hallux valgus deformity remains challenging despite the various methods presented. This study aimed to compare the effectiveness of minimally invasive distal chevron Akin osteotomies (d-MICA) and minimally invasive proximal chevron Akin osteotomies (p-MICA) in correcting severe hallux valgus deformities.

METHODS

This prospective follow-up study included patients randomly assigned to undergo p-MICA or d-MICA for hallux valgus deformities with a preoperative hallux valgus angle (HVA) ≥ 40° and/or a first to second intermetatarsal angle (IMA) ≥ 16°. After a minimum follow-up period of two years, we compared various clinico-radiographic parameters of patients whose HVA exceeded 15° at the final follow-up.

RESULTS

In the p-MICA and d-MICA groups, seven of 40 cases (17.5%) and 16 of 41 cases (39.0%), respectively, exhibited HVA > 15° at the final follow-up (P = 0.048). The preoperative parameters showed no significant differences. However, at the first weight-bearing assessment, the HVA, IMA, and relative second metatarsal length were significantly smaller, and the distal metatarsal articular angle (DMAA) was greater in the p-MICA group (all P < 0.05) compared with the d-MICA group. Postoperatively, both groups exhibited significant decreases in HVA and IMA at the final follow-up (P < 0.001 for all parameters). The p-MICA group showed no significant changes in DMAA and the relative length of the second metatarsal (P = 0.253 and 0.185, respectively). However, the d-MICA group showed a significant decrease in DMAA (P < 0.001) and an increase in the relative length of the second metatarsal at the final follow-up (P = 0.01).

CONCLUSIONS

p-MICA and d-MICA procedures demonstrated effective correction potential for severe hallux valgus deformities; however, the d-MICA procedure exhibited a notably higher incidence of unsatisfactory correction at the final follow-up than p-MICA. Therefore, d-MICA may be less predictable in achieving successful outcomes than p-MICA in treating severe hallux valgus deformities.

Minimally invasive Chevron-Akin (MICA) osteotomies without Akin fixation in hallux valgus correction: a case series with 2-year follow-up

PURPOSE

The minimally invasive Chevron-Akin (MICA) is considered the third generation of minimally invasive hallux valgus (HV) surgery, and its original description included fixation of the Akin osteotomy with a screw. The aim of this study is to evaluate a series of patients undergoing HV correction using the MICA technique without screw fixation of the Akin osteotomy.

METHODS

We retrospectively evaluated 58 consecutive patients who underwent surgical correction for HV between August 2018 and March 2020. A total of 69 feet were evaluated with a minimum follow-up of 2 years. Clinical outcomes such as pain (VAS), function (AOFAS), range of movement, criteria personal satisfaction and complications were evaluated.

RESULTS

The AOFAS score (mean ± standard deviation) significantly improved from 57.0 ± 8.6 preoperatively to 93.9 ± 8.7 postoperatively (p < .001) with a minimum follow-up of 2 years. The VAS score improved from 6.0 ± 1.8 preoperatively to 0.6 ± 1.4 at 2-year follow-up (p < .001), and the hallux valgus angle reduced from 39.7 ± 6.9 to 8.9 ± 9.0 (p < .001). The majority of patients (95.6%) reported the result as excellent or good, and the most common complication was the need to remove the screw (7.2%).

CONCLUSIONS

The use of MICA without Akin osteotomy fixation resulted in successful correction of hallux valgus with improvements in clinical and radiographic parameters.

LEVEL OF EVIDENCE

IV, case series.

Minimally Invasive Chevron Akin (MICA) Osteotomy Corrects Radiographic Parameters but Not Central Metatarsal Loading in Moderate to Severe Hallux Valgus without Metatarsalgia

BACKGROUND

Central metatarsal pressure is increased in patients with hallux valgus, but the pedographic outcomes after hallux valgus (HV) correction are inconclusive. No known literature has reported the pedographic outcomes after HV correction with Minimally Invasive Chevron and Akin Osteotomy (MICA).

METHODS

A prospective cohort of 31 feet from 25 patients with moderate-to-severe symptomatic HV but without metatarsalgia underwent MICA and was evaluated using radiographic parameters and pedographic measurements (Footscan®, RSscan International, Olen, Belgium). Data were collected preoperatively and 3 months after surgery.

RESULTS

The radiographic parameters of the hallux valgus angle, intermetatarsal angle, distal metatarsal articular angle, first metatarsal head lateral shape, and lateral sesamoid grade significantly improved after MICA. The corrected first metatarsal length was significantly shortened by 2.3 mm, with consistent second metatarsal protrusion distance, lateral Meary's angle, and calcaneal pitch angle. Max force, max pressure, cumulative force, and cumulative pressure on the central metatarsals did not show significant changes between pre- and post-operative measurements, while these parameters significantly decreased in the hallux and first metatarsal area.

CONCLUSION

MICA effectively corrects radiographic parameters but does not reduce central metatarsal loading in patients with moderate-to-severe HV without metatarsalgia.

A Joy-Stick Assistant Three-Dimensional Modified Technique of Minimally Invasive Surgery for Mild or Moderate Hallux Valgus

BACKGROUND

Minimally invasive surgery (MIS) such as minimally invasive chevron osteotomy and Akin osteotomy (MICA) has become popular in the treatment of hallux valgus. However, how to correct three-dimensional deformities in hallux valgus effectively and simply in MICA is still difficult. Special equipment is required in MICA as has been reported before. It is meaningful and necessary to reduce the reliance on special equipment in MICA.

METHODS

From January 2021 to July 2022, patients with mild or moderate hallux valgus were treated with a joy-stick assistant three-dimensional modified technique (Joy-stick 3D technique) of MIS. VAS, AOFAS Hallux MTP-IP scores, hallux valgus angle (HVA), intermetatarsal angle (IMA), and distal metatarsal articular angle (DMAA) were measured pre- and postoperatively at the last follow-up of at least 6 months. Scores and radiologic angles were compared using paired sample t-test.

RESULTS

A total of 36 cases were included. HVA, IMA, and DMAA were (22.3 ± 6.1)°, (14.0 ± 3.2)°, and (8.9 ± 3.2)° preoperatively, and decreased to (7.0 ± 1.8)°, (3.7 ± 1.0)°, and (3.3 ± 1.1)° postoperatively. VAS decreased from 4.3 ± 1.7 to 0.7 ± 0.7. AOFAS Hallux MTP-IP scores improved from 68.6 ± 7.6 to 92.9 ± 6.1. Comparing mild and moderate cases, though HVA, IMA, and DMAA were significantly different preoperatively, the angles became statistically similar after surgery.

CONCLUSIONS

A joy-stick assistant three-dimensional modified technique is proposed to control the three-dimensional position of the metatarsal head and to reduce dependence on special tools. Mild and moderate hallux valgus deformities are effectively corrected using Joy-stick 3D technique.

Clinical guideline on the third generation minimally invasive surgery for hallux valgus

Minimally invasive surgery for hallux valgus correction, has been attracting great interests in the recent decades, due to the potential benefits of less pain, decreased recovery times, smaller scars with better cosmesis, and improved early post-operative range of motion. The most recent developments in minimally invasive surgery have evolved into the third generation with modifications of the chevron-type osteotomy. This evidence-based clinical guideline of the third generation minimally invasive surgery for hallux valgus is initiated and developed collectively by the Foot and Ankle Committee of Orthopedic Branch of Chinese Medical Doctor Association, Foot and Ankle Committee of Sports Medicine Branch of Chinese Medical Doctor Association, and Foot and Ankle Expert Committee of Orthopedic Branch of the Chinese Association of the Integrative Medicine. This clinical guideline provides recommendations for indications, contraindications, operative planning and techniques, post-operative management, management of complications, and prognosis of the third generation minimally invasive surgery for hallux valgus. The Translational Potential of this Article This comprehensive guideline aims to establish standardized recommendations for the indications, contraindications, operative techniques, and post-operative management of the third generation minimally invasive surgery for hallux valgus. By adhering to this guideline, the success rate of the procedure could be maximized. This comprehensive guideline serves as a valuable reference for practitioners interested in or preparing to perform minimally invasive surgery for hallux valgus.

Does the Presence of Asymptomatic Flatfoot Deformity Impact the Clinical and Radiographic Outcomes of the Minimally Invasive Chevron and Akin Bunionectomy?

BACKGROUND

Flatfoot deformity is believed to play a role in hallux valgus development and recurrence. While symptomatic flatfoot deformity can be treated with separate procedures at the time of hallux valgus correction, the question remains whether the patient undergoing correction of a symptomatic hallux valgus deformity should have their asymptomatic flatfoot concurrently addressed. We aimed to investigate whether the presence of asymptomatic flatfoot influences patient-reported and radiographic outcomes of the minimally invasive chevron and Akin bunionectomy.

METHODS

A total of 104 patients were included in this study. Forty-two asymptomatic patients met the radiographic criteria for flatfoot while 62 had a normal arch. Patient-reported outcomes were evaluated and compared between the two groups using validated PROMIS measures preoperatively and at a minimum one-year postoperatively. Radiographic outcomes including hallux valgus angle (HVA), intermetatarsal angle (IMA), Meary's angle, calcaneal pitch (CP), and talonavicular coverage angle (TNCA) were measured and compared preoperatively and minimum six-months postoperatively.

RESULTS

Both groups demonstrated similar preoperative and postoperative PROMIS scores with significant improvements in physical function, pain interference, pain intensity, and global physical health. Preoperatively, HVA was similar between both groups, however the flatfoot group showed a greater IMA, Meary's angle, TNCA, and lower CP. Postoperatively, HVA and IMA were similar between groups, although patients in the flatfoot group retained a significantly greater Meary's angle, TNCA, and lower CP. Both groups showed significant improvements in HVA, IMA, and TNCA.

CONCLUSION

Our study indicates that the minimally invasive chevron and Akin bunionectomy leads to improved clinical and radiographic hallux valgus outcomes without adversely impacting radiographic flatfoot parameters. Therefore, the MIS bunionectomy may be an effective option for hallux valgus correction in patients with mild, asymptomatic flatfoot.

LEVEL OF EVIDENCE

Level III, retrospective cohort.

Minimally Invasive Chevron Akin Osteotomy: Preoperative Planning Using the Radiographic First-Ray Squeeze Test

Background

Recognizing preoperative first-ray hypermobility is important to planning hallux valgus (HV) surgery. A recent study showed the minimally invasive chevron Akin (MICA) osteotomy increased varus displacement of the proximal fragment of the first metatarsal osteotomy. The present study aims to evaluate the ability of the radiographic first-ray squeeze test to predict the varus displacement of the proximal fragment of the first metatarsal osteotomy when performing the MICA procedure.

Methods

A prospective case series of patients with moderate to severe HV who underwent MICA was performed. The HV deformity correction was analyzed by comparing the preoperative and 12-week postoperative hallux valgus angle (HVA) and the intermetatarsal angle between the first and second rays (1-2 IMA). The ability of the radiographic first-ray squeeze test to predict the varus displacement of the first metatarsal was done by comparing the preoperative 1-2 IMA measured in the AP radiographic first-ray squeeze test (IMA-ST) with the intermetatarsal angle between the second metatarsal and the axis of the first metatarsal osteotomy proximal fragment (IAPF) taken 12 weeks postoperatively.

Results

Between July 2022 and May 2023, a total of 39 feet in 28 patients underwent MICA. The mean IMA improved from 13.8 (SD = 2.2) to 3.8 degrees (SD = 1.5) (P < .001), and the mean HVA improved from 27.8 (SD = 6.1) to 4.9 degrees (SD = 2.5) (P < .001). A linear regression analysis revealed that IMA-ST is highly associated with the 12 week assessed IAPF (P < .001).

Conclusion

The preoperative radiographic first-ray squeeze test appears to predict with high fidelity the varus displacement of the proximal fragment of the first metatarsal that can occur after the MICA procedure.Level of Evidence: Level III, prospective cohort study.

Minimally Invasive Transverse Distal Metatarsal Osteotomy (MITO) for Hallux Valgus Correction: Early Outcomes of Mild to Moderate vs Severe Deformities

BACKGROUND

We compared the radiological and clinical outcomes of mild to moderate and severe hallux valgus (HV) treated with minimally invasive distal metatarsal transverse osteotomy (MITO) performed by a single surgeon.

METHODS

Eighty-four patients who underwent MITO between May 2018 and March 2020 were recruited and followed for at least 24 months. The severe group was defined as having a preoperative hallux valgus angle (HVA) >40 degrees or preoperative first-to-second intermetatarsal angle (1-2 IMA) >16 degrees; the mild to moderate group was defined as having an HVA <40 degrees and a 1-2 IMA <16 degrees. Pre- and postoperative measurements of the HVA, 1-2 IMA, distal metatarsal articular angle, and tibial sesamoid position were obtained. The visual analog scale for pain, the Foot and Ankle Outcome Score, and the Medical Outcomes Study Short Form Health Survey-36 physical component summary were used to assess clinical outcomes.

RESULTS

A total of 116 feet were included in this study and median follow-up period of 29.0 months (range, 24-52 months). Both groups showed significant improvements in all radiologic parameters postoperatively, with the degrees of correction greater in the severe group than in the mild to moderate group. All clinical scores improved significantly from the preoperative to the last follow-up visit. Final clinical outcomes and degrees of improvement were comparable in both groups.

CONCLUSION

This study showed that short-term radiographic results for patients with either mild to moderate or severe HV treated with MITO were favorable. Overall clinical outcomes were comparable to those of conventional treatments. In this series, we found MITO with screw fixation to be a satisfactory surgical option for patients with mild to severe HV deformities.

LEVEL OF EVIDENCE

Level III, retrospective comparative study.

Minimally invasive Chevron Akin (MICA) osteotomy for severe hallux valgus

INTRODUCTION

The minimally invasive Chevron Akin (MICA) osteotomy has been widely used to treat hallux valgus (HV). The purpose of this study was to present a case series of patients with severe HV undergoing surgical treatment using the MICA procedure and to evaluate the clinical and radiographic outcomes.

MATERIALS AND METHODS

Retrospective study including 60 consecutive feet (52 patients) undergoing MICA for severe HV. The data were collected pre- and post-operatively at the last follow-up. Patients were clinically evaluated by the visual analog pain scale (VAS) and AOFAS hallux MTP-IP score. Radiographic assessments included measurements of hallux valgus angle (HVA), intermetatarsal angle (IMA), metatarsal (MT) length, distal metatarsal articular angle (DMAA), and plantar translation of MT head. The complications were recorded during the follow-up.

RESULTS

The mean age was 59.9 years, and the mean follow-up was 20.5 months. The average AOFAS increased from 41.2 to 90.9 points, and the VAS from 8.1 to 1.3 at the last follow-up. The average HVA decreased from 41.2º to 11.6º, the IMA from 17.1º to 6.9º, and the DMAA from 17.9º to 7.8º. The average shortening of the first metatarsal and the plantar translation of the MT head was 5.1 mm and 2.8 mm, respectively. The most observed complication was hardware discomfort, observed in 5 feet (8.3%). There were two cases of recurrence (3.3%).

CONCLUSION

MICA technique was demonstrated in this series of cases to be an effective procedure for severe HV, with a low rate of recurrence and an acceptable rate of complications.

LEVEL OF EVIDENCE

IV; case series.

Severe hallux valgus can be treated using a distal metatarsal osteotomy: Results of 144 cases treated with the SERI technique

PURPOSE

Aim of this study is to analyze the clinical and radiographic results of the simple, effective, rapid and inexpensive (SERI) technique, a linear distal metatarsal osteotomy, for treating severe hallux valgus (HV).

METHODS

Clinical outcomes were assessed pre- and postoperatively using the AOFAS, MOxFQ and VAS score. Pre and postoperative HV angle (HVA) and intermetatarsal angle (IMA) were measured.

RESULTS

117 consecutive patients for a total of 144 feet were included. Pre and postoperatively, mean AOFAS changed from 44.8 ± 16.7 to 89 ± 10.3 (p < .001), mean MOxFQ changed from 76.2 ± 15.8 to 23.4 ± 7.9 (p < .001) and mean VAS score improved from 6.7 ± 2.1 to 1.5 ± 1.5 (p < .001). HVA diminished from 40.6° ± 6.9 preoperatively to 16.0° ± 7.3 postoperatively (p < .001). IMA decreased from 15.1° ± 2.8 preoperatively to 6.5° ± 2.4 postoperatively (p < .001). The main complication reported was stiffness (10.4 %).

CONCLUSION

SERI technique applied to severe HV showed positive clinical and radiological outcomes. A careful patient selection and a low grade first MTPJ arthritis are essential to obtain favorable results.

LEVEL OF EVIDENCE

IV.

Temporal Changes in Clinical Outcomes after Minimally Invasive Surgery for Hallux Valgus Correction in Women without Postoperative Complications

Minimally invasive surgery (MIS) is currently used to correct hallux valgus deformities. Most studies reporting on MIS techniques to correct hallux valgus deformities included patients with postoperative complications. These reported complications, with an average rate of 23%, had significant negative effects on the clinical outcomes in this patient population. In the present study, a cohort of 63 women who underwent MIS hallux valgus correction was assessed preoperatively and at a mean follow-up of 1.0, 4.7, and 6.5 years using the American Orthopaedic Foot and Ankle Society (AOFAS) scale and the Manchester Oxford Foot Questionnaire (MOXFQ). The main criterion for inclusion in this cohort was a lack of complications during the entire follow-up period. The results showed significant improvements in both AOFAS and MOXFQ scores between the preoperative and 1-year follow-up assessments. By contrast, clinically small and nonsignificant changes were observed among postoperative follow-up values. The number of enrolled patients needs to be increased in future studies, with different surgeons and techniques included. Nevertheless, our study findings will inform patients about the outcomes they can expect over the years if no complications occur.

Fourth-Generation Minimally Invasive Hallux Valgus Surgery With Metaphyseal Extra-Articular Transverse and Akin Osteotomy (META): 12 Month Clinical and Radiologic Results

BACKGROUND

Fourth-generation minimally invasive surgery (MIS) includes the multiplanar rotational deformity correction achieved through manipulation of an extra-articular distal first metatarsal osteotomy that is held with rigid fixation using 2 fully threaded screws, of which one must be bicortical to provide rotational and biomechanical stability. The aim of this study is to report the clinical and radiologic outcomes of an evolved fourth-generation MIS hallux valgus technique.

METHODS

A prospective single-surgeon series of consecutive patients undergoing fourth-generation MIS was performed using a distal transverse osteotomy with a minimum 12-month follow-up. The primary outcome was the Manchester-Oxford Foot Questionnaire (MOXFQ), a validated clinical patient-reported outcome measure (PROM). Secondary outcomes included radiographic deformity correction, clinical assessment, and EuroQol-5D-5L PROMs.

RESULTS

Between September 2019 and June 2021, 50 feet underwent fourth-generation MIS. The mean age was 55.8±15.3 years with a mean follow-up of 1.4 years. Preoperative and minimum 12-month primary outcome data were available for 100% of feet. There was a significant improvement in all MOXFQ domain scores, with the index domain improving from 53.4 to 13.1 (P < .001). There was a significant improvement (P < .001) in hallux valgus angle (32.7 to 7.9 degrees), intermetatarsal angle (14.0 to 4.2 degrees) and distal metatarsal articular angle (18.5 to 5.6 degrees). There was a significant improvement in general health-related quality of life EQ-5D-5L index and EQ-VAS scores (P < .05).

CONCLUSION

The fourth-generation MIS technique is a safe and effective approach to hallux valgus deformity correction with significant improvement in clinical and radiographic outcomes.

LEVEL OF EVIDENCE

Level IV, prospective case series.

Minimally Invasive Surgery Using a Shannon Burr for the Treatment of Hallux Valgus Deformity: A Systematic Review

Background

Recently there has been an increase in minimally invasive surgery (MIS) for the correction of hallux valgus deformity. This systematic review aims to evaluate and present the current literature on MIS hallux valgus correction in studies reporting the use of the Shannon burr with distal metatarsal osteotomies to help establish evidence-based guidelines for surgeons using this technique.

Methods

Two independent authors performed a systematic literature search using the following databases: PubMed, Embase, and the Cochrane library. The Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) protocol and the Cochrane Handbook guidelines were followed. All studies included were published from 2008 to 2022 and included the use of the Shannon burr during distal metatarsal osteotomies MIS for hallux valgus and at least 12-month follow-up. The MINORS score criteria was used to evaluate the strength and quality of 17 studies by 3 authors. Statistical analysis and meta-analysis were not performed because of the heterogeneity of the included studies and the data being descriptive.

Results

A total of 17 studies were reviewed. A total of 911 subjects were included, and 1088 MIS procedures were performed. The average follow-up was 23.8 (12-59.1) months. American Orthopaedic Foot & Ankle Society scale and visual analog scale scores improved from 52.1 (41-62.5) to 90.3 (83.3-97.1) and 4.9 (3-8.2) to 0.8 (0-1.9). Satisfaction rates were very high among the studies that reported it. The hallux valgus angle, intermetatarsal angle, and distal metatarsal articular angle improved from 31.4 (23.5-44.1) to 11.1 (7-17.2), 13.4 (8.1-18.6) to 7.3 (4.2-10.3), and 12.3 (9-16.3) to 4.1 (1-6.7), respectively. The complication rate was 16.6%, and recurrence was 2.2%. Nonunion comprised 0.4%, infections 1.1%, nerve injury 2.2%, avascular necrosis 0%, hallux varus 0.09%, transfer metatarsalgia 0.1%, and hardware removal 6.2%.

Conclusion

MIS for the treatment of hallux valgus using the Shannon burr appears to be a safe and effective therapy, with appropriate correction of the hallux valgus deformity, improvement in functional outcomes, high patient satisfaction, low recurrence, and acceptable complication rates.

Level of Evidence

Level II, systematic review.