MICA: A Learning Curve

A comparison of three techniques for the osteosynthesis after minimal invasive osteotomies for hallux valgus

PURPOSE

Third and fourth-generation minimal invasive osteotomies (MIO) for the treatment of hallux valgus (HV) have become popular procedures worldwide with promising results due to the improvement in the fixation method. The tricortical cannulated screw placement remains a complex procedure that is technically challenging and requires a long skill learning curve with high radiation exposure mainly in the form of intensifier shots (IS) required for the MIO fixation. This study aims to compare the number of X-ray IS required using three different techniques for the cannulated guide placement.

METHODS

A retrospective cross-sectional observational and comparative study was conducted to assess the number of X-rays IS required for correct cannulated screw guide placement using three different techniques: traditional perforator, the drill and joystick, and K-wire first techniques.

RESULTS

A total of 53 MIS procedures from thirty-one patients in two different hospitals were included. IS X-rays were 155.1 ± 29.7 in the traditional technique (n = 14), 143.0 ± 43.2 in the drill and joystick technique (n = 22), and 85 ± 18.7 in the K-wires first technique (n = 17), p =  < 0.001 using one-way ANOVA.

CONCLUSIONS

The K-wire first technique statistically significantly decreases X-ray IS numbers p ≤ 0.001. There were no statistically significant differences between the traditional (after osteotomy K-wire placement) and the drill and joystick techniques (p = 0.36).

The Effect of First Metatarsal Shortening and Sagittal Displacement on Forefoot Pressure in Minimally Invasive Hallux Valgus Correction

BACKGROUND

Minimally invasive (MIS) treatment of hallux valgus (HV) deformity is increasing in popularity. A 2-mm diameter burr is used to create a distal first metatarsal osteotomy prior to capital fragment translation and fixation. The metatarsal will shorten by the burr's diameter (2 mm). Plantar or dorsal capital fragment displacement may also cause load transference and possibly transfer metatarsalgia. The purpose of this study is to examine the effect of MIS HV on forefoot loading mechanics with respect to metatarsal shortening and sagittal plane displacement.

METHODS

Four lower-limb cadaveric specimens were studied. A pedobarography pressure-sensing mat was used to record forefoot plantar pressure in a controlled weight-bearing stance position. Control and postosteotomy measurements were obtained with the capital fragment fixated in 3 possible positions: 0 mm, 5 mm dorsal, and 5 mm plantar displacement. Pedobarography data yielded pressure data within measurable graphical depictions. Raw mean contact pressure measurements were taken under the first and fourth metatarsal heads to establish medial and lateral forefoot loading pressure ratios. An a priori power analysis was performed based on previous peer-reviewed pedobarographic data, and our study was adequately powered.

RESULTS

Around 40 measurements were recorded, and ratios of medial-to-lateral forefoot loading were constructed. Medial forefoot pressure control versus 0 mm displacement, and control versus dorsal displacement were not found to be statistically significant (p = 0.525, p = 0.55, respectively). Medial pressure significantly increased when comparing control versus plantar displacement (P = .006). Lateral pressure significantly increased with dorsal displacement of the osteotomy (P = .013).

CONCLUSION

Our study found that MIS HV correction did not cause an increase in lateral forefoot pressure loading when sagittal plane displacements were controlled. Plantar displacement increased medial loading, and dorsal displacement increased lateral loading. It may be valuable for surgeons to consider metatarsal head position postosteotomy, as a decrease in medial loading and subsequent increase in lateral loading may lead to lateral forefoot pain and transfer metatarsalgia.

LEVELS OF EVIDENCE

IV.

The surgical learning curve for percutaneous Zadek osteotomy for treatment of insertional achilles tendinopathy

INTRODUCTION

The Zadek Osteotomy has been described as an effective technique for the treatment of insertional Achilles tendinopathy. Recently, this strategy has been modified using minimally invasive techniques. A learning curve has been observed in many minimally invasive procedures in foot and ankle surgery. This retrospective study first intended to evaluate if there is a learning curve associated with the percutaneous Zadek Osteotomy. Further, if a learning curve was observed, we planned to assess the data for associated changes in complications and postoperative outcomes.

METHODS

A retrospective analysis of 98 patients who underwent percutaneous Zadek Osteotomy was performed. Patient charts were reviewed for operative times, complications, union rates, and Foot Function Index (FFI) and Visual Analogue Scale (VAS) scores. Analysis of variance was utilized to assess for differences between groups of cases.

RESULTS

Patients included 61 females and 37 males. Mean age was 51.28 ± 11.12 (range 28-81) years. Mean follow-up time was 42.07 ± 12.99 (range 24-65) months. Significant increases in operative times were observed in cases 1-14 when compared to cases 15-98 (p < 0.001). Improvements in FFI and VAS scores were observed at final follow-up within each case group (p < 0.001); there were no differences detected in FFI or VAS scores between groups of cases. There was no difference detected in number of complications between intervals of cases.

CONCLUSION

A learning curve was observed for the percutaneous Zadek Osteotomy, which was overcome around case 14. This learning curve was only observed in terms of procedure length. A surgeon's level of inexperience with the technique does not appear to affect functional outcomes, nonunion, or need for revision.

LEVEL OF EVIDENCE IV

Data will not be deposited in a repository.

Improving the Accuracy of Metatarsal Osteotomies in Minimally Invasive Foot Surgery Using a Digital Inclinometer: Preliminary Study

Minimally invasive foot surgery (MIS) has become a common procedure to treat various pathologies, and accuracy in the angle of metatarsal osteotomies is crucial to ensure optimal results. This randomized controlled trial with 37 patients investigates whether the implementation of a digital inclinometer can improve the accuracy of osteotomies compared to traditional freehand techniques. Patients were randomly allocated to group A (n = 15) receiving inclinometer-assisted surgery or group B (n = 22) receiving conventional surgery. Osteotomies were performed and outcomes were evaluated using an inclinometer. The inclinometer group showed a significant decrease in plantar pressure from 684.1 g/cm2 pretreatment to 449.5 g/cm2 post-treatment (p < 0.001, Cohen's d = 5.477). The control group decreased from 584.5 g/cm2 to 521.5 g/cm2 (p = 0.001, Cohen's d = 0.801). The effect size between groups was large (Cohen's d = -2.572, p < 0.001). The findings indicate a significant improvement in accuracy and reduction in outliers when using an inclinometer, suggesting that this technology has the potential to improve surgical practice and patient outcomes in minimally invasive metatarsal osteotomies.

The Surgical Learning Curve for Modified Lapidus Procedure for Hallux Valgus Deformity

BACKGROUND

Hallux valgus is one of the most common orthopaedic deformities of the foot, affecting as much as 23% of the population age 18 to 65. In addition to its high prevalence, it has a complex multifactorial pathogenesis. Surgical correction options have variable rates of success and new techniques are being developed. The modified Lapidus procedure attempts to correct in 3 planes of deformity, which may create a steeper learning curve for those newly adopting the technique.

METHODS

A retrospective review was performed on patients who underwent hallux valgus reconstruction with a modified Lapidus procedure between March 2018 and July 2020. Exclusion criteria included revision surgery, 6 or more concurrent procedures, or a flexor digitorum longus tendon transfer for adult acquired flatfoot correction.

RESULTS

There were a total of 81 modified Lapidus procedures for hallux valgus within the study time frame and 68 were included in the study. Over a period of 2 years there was a significant decrease in overall surgery duration from 78.93 minutes at month 0 to 61.80 minutes at 24 months (P = .036). The average preoperative/postoperative intermetatarsal angles were 15.08° and 4.91°, respectively. There was an average decrease of 10.17°. The rate of nonunion was 4.41% (3/68), and the rate of recurrence at 6 months was 5.88% (4/68). There was not a significant difference in the rate of recurrence (P = .394) or the rate of nonunion (P = .817) as the surgeon increased in experience.

CONCLUSION

Although there is a significant learning curve for the modified Lapidus procedure, it is largely overcome by the 23rd case. Additionally, experience with the technique does not appear to affect the patient outcomes of nonunion or recurrence.

LEVELS OF EVIDENCE

Level IV: Retrospective.

Learning curve associated with minimally invasive surgery for hallux valgus: A systematic review

BACKGROUND

The purpose of this systematic review is to examine the learning curve associated with minimally invasive surgery (MIS) for the treatment of hallux valgus (HV).

METHODS

A systematic review was performed using PubMed, ScienceDirect, Web of Science, CINAHL and MEDLINE databases from database inception to February 16th, 2023. Inclusion criteria was articles with level of evidence I-III, any outcomes associated with learning curve, minimally invasive surgery, and diagnosis of hallux valgus' in adult patients.

RESULTS

Six articles out of 165 articles meet inclusion criteria. For all six articles, 368 total patients (422 total feet) were included in the study with an average age of 55.69 years. Three studies reported the number of surgeries needed to reach the plateau phase of the learning curve of MIS for HV, with a frequency weighted mean of 35.5 surgeries (range 27 - 40). In the selected articles, significant results were found for increased operating room (OR) time and fluoroscopy shots in the learning phase. There was no significant increase in complications in the learning phase. There was no significant decrease in patient outcomes, or the quality of correction performed during the learning phase.

CONCLUSION

An average of 35.5 surgeries (range 27 - 40) are needed to reach the plateau phase for MIS for HV. The learning phase of the learning curve of MIS for HV has a significant increase in OR time and fluoroscopy usage. However, the learning phase of the learning curve of MIS for HV is not associated with decreased outcomes or higher complication rates based on the small sample size in this study.

LEVEL OF EVIDENCE

Level III, Systematic Review.

A Modified 90-Degree Distal Chevron Metatarsal Osteotomy for Correcting Moderate Hallux Valgus Deformity

Various modifications of distal chevron metatarsal osteotomy (DCMO) have been introduced for correcting moderate hallux valgus deformity; however, the amount of correction may be limited, and complications, such as the recurrence of the deformity and avascular necrosis of the metatarsal head, have been a problem. This study aimed to present a modified 90-degree DCMO technique that overcomes the previously reported shortcomings and to report a successful short-term radiographic outcome. Sixty-eight consecutive patients who underwent the operation with our modified DCMO technique and twenty-two consecutive patients with the conventional DCMO technique (control group) were retrospectively analyzed. The radiographic measurements were evaluated preoperatively, at two months post operation, and at the final follow-up. Both groups showed a significant correction of the hallux valgus angle, first-second intermetatarsal angle, distal metatarsal articular angle, and sesamoid position at the final follow-up, while the amount of correction was significantly greater in the modified DCMO group. In both groups, there were no cases of complications such as avascular necrosis of the metatarsal head, nonunion, and surgical site infection appearing throughout the follow-up period. Therefore, the modified 90-degree DCMO technique is effective and safe, which could serve as a favorable option to treat moderate hallux valgus deformity.

Determining the frequency of burn wound dressing for clinically competent nursing students: establishing standards based on learning curves

BACKGROUND

The primary objective of clinical practice in nursing education is to achieve mastery of clinical skills through repetitive practice. Therefore, there exists a correlation between the frequency of skill demonstration and clinical competency. This study aimed to address the following question: How many times should a nursing student perform burn wound dressing to attain clinical competency?

METHODS

This time series study was conducted on 41 junior nursing students who were selected through a census sampling method at Neyshabur School of Nursing from spring 2015 to summer 2021. The data collection tool was a researcher-made competency evaluation checklist (CEV). The competency score of each student for each skill demonstraion episode was evaluated using the Competency Evaluation Checklist (CEV) and recorded on the learning curve until a plateau was reached. SPSS16 and repeated measures analysis of variance (ANOVA) were used.

RESULTS

The mean competency score of burn wound dressing was 67.5 ± 11.0 (out of 100) during the first attempt, which increased to 95.9 ± 4.3 by the ninth attempt. The learning curve for the burn wound dressing skill reached a plateau after five attempts. Additionally, by the fifth attempt of dressing the burn wound, all students could accurately identify the depth, extent, and severity of the wound.

CONCLUSIONS

Establishing a standardized frequency for clinical skill performance and ensuring ample practice opportunities can have significant benefits in nursing education systems. These benefits include long-lasting learning, reduced costs, and improved effectiveness. As a result, nurse managers and lecturers should consider the resources available in their educational systems and strive to provide students with adequate opportunities and a supportive environment to practice their skills.

Learning curve in relation to radiation exposure, procedure duration and complications rate for Minimally Invasive Chevron Akin (MICA) osteotomy

BACKGROUND

Minimally invasive chevron Akin osteotomy (MICA) has become increasingly common and is compatible with the traditional open approaches for hallux valgus correction. However, it is impeded by concerns regarding the steep learning curve, increased radiation exposure and some specific complications. No standardized method for identifying a learning curve exists. We used a reproducible mathematical model to accurately define the learning curve of MICA with a focus on fluoroscopy time, procedure duration and complications rate.

METHODS

We conducted a retrospective study of MICA procedure performed by a single surgeon during his initial experience with this procedure. The chronologic case number was plotted against variables of interest and learning was identified as the point at which instantaneous rate of change of a curve fit to the data set equalled the average rate of change of the data set.

RESULTS

One hundred cases have been analysed. Learning plateau in operation time was achieved after 29 cases, with the first 29 cases requiring a median of 60 min compared to 40 min for the latter 71 cases. Proficiency in fluoroscopy application occurred in case 30. The median fluoroscopy time for the first 30 cases was 86 seconds compared to 70 seconds in another 70 cases. The complication rate plateau was reached after 42 cases, with 15 of 22 complications occurring in the group operated first.

CONCLUSION

Results demonstrate surgeon's comfort with MICA to minimize operative time and radiation exposure after 30 cases. The plateau is achieved later for complications. Findings impose lag between surgeon feeling comfortable with procedure and a decrease in complications. Further research is reasonable to analyse several surgeons learning curve and to generate a potential reference learning curve that could serve as a normative.

TRIAL REGISTRATION

UKC-MB-KME-33/19, retrospectively registered.

Third-Generation Minimally Invasive Chevron Akin Osteotomy for Hallux Valgus: Three-Year Outcomes

Introduction

Numerous minimally invasive techniques have been developed for Hallux Valgus in recent years. Third-generation Minimally Invasive Chevron Akin (MICA) osteotomy has shown promising early results, but longer-term follow-up is required to assess whether patient clinical and radiological improvement is sustained. This cohort study presents three-year follow-up outcomes for patients of a single surgeon case series.

Methods

Thirty-three patients underwent third-generation MICA surgery between 2017 and 2018. Patient clinical-reported outcome measures included American Orthopaedic Foot & Ankle Society (AOFAS), Manchester-Oxford Foot Questionnaire (MOXFQ) scores, and Coughlin satisfaction. Radiographic outcomes were evaluated after a period of three years using hallux valgus angle (HVA) and inter-metatarsal angle (IMA), and compared to pre- and early post-operative outcomes.

Results

At 36 months, mean AOFAS scores improved from 48.2 to 95.6, mean MOXFQ scores improved from 57.6 to 6.7. Using the Coughlin scale, 81.8% of patients rated their outcome as 'Excellent' and 18.2% as 'Good'. Radiographic outcomes showed HVA and mean IMA decreased from 34.6 degrees to 16.0 degrees and from 13.1 to 6.1, respectively at 36 months.

Conclusion

Third-generation MICA demonstrates promising patient satisfaction scores post-operatively, and we have shown these improvements are sustained over a minimum three-year follow-up period.

Level of Evidence

Level IV, case series.

Does Minimally Invasive Surgery Provide Better Clinical or Radiographic Outcomes Than Open Surgery in the Treatment of Hallux Valgus Deformity? A Systematic Review and Meta-analysis

BACKGROUND

Hallux valgus is the most common foot deformity and affects 23% to 35% of the general population. More than 150 different techniques have been described for surgical correction. Recently, there has been increasing interest in the use of minimally invasive surgery to correct hallux valgus deformities. A variety of studies have been published with differing outcomes regarding minimally invasive surgery. However, most studies lack sufficient power and are small, making it difficult to draw adequate conclusions. A meta-analysis can therefore be helpful to evaluate and compare minimally invasive and open surgery.

QUESTIONS/PURPOSES

We performed a systematic review and meta-analysis of randomized controlled trials and prospective controlled studies to answer the following question: Compared with open surgery, does minimally invasive surgery for hallux valgus result in (1) improved American Orthopaedic Foot and Ankle Society (AOFAS) scores and VAS scores for pain, (2) improved radiologic outcomes, (3) fewer complications, or (4) a shorter duration of surgery?

METHODS

The systematic review and meta-analysis was conducted according to the guidelines of the Cochrane Handbook for Systematic Reviews of Intervention and the Preferred Reporting Items for Systematic Reviews and Meta-analyses. A search was performed in the PubMed, Embase, Scopus, CINAHL, and CENTRAL databases on May 3, 2022. Studies were eligible if they were randomized controlled or prospective controlled studies that compared minimally invasive surgery and open surgery to treat patients with hallux valgus. We defined minimally invasive surgery as surgery performed through the smallest incision required to perform the procedure accurately, with an incision length of approximately 2 cm at maximum. Open surgery, on the other hand, involves a larger incision and direct visualization of deeper structures. Seven studies (395 feet), consisting of six randomized controlled studies and one prospective comparative study, were included in the qualitative and quantitative data synthesis. There were no differences between the minimally invasive and open surgery groups regarding age, gender, or severity of hallux valgus deformity. Each included study was assessed for the risk of bias using the second version of the Cochrane tool for assessing the risk of bias in randomized trials or by using the Newcastle-Ottawa Scale for comparative studies. Most of the included studies had intermediate quality regarding the risk of bias. We excluded one study from our analysis because of its high risk of bias to avoid serious distortions in the meta-analysis. We performed a sensitivity analysis to confirm that our meta-analysis was robust by including only studies with a low risk of bias. The analyzed endpoints included the AOFAS score (range 0 to 100), where higher scores represent less pain and better function; the minimum clinically important difference on this scale was 29 points. In addition, the VAS score was analyzed, which is based on a pain rating scale (range 0 to 10), with higher scores representing greater pain. Radiologic outcomes included the hallux valgus angle, intermetatarsal angle, and distal metatarsal articular angle. Complications were qualitatively assessed and evaluated for differences. A random-effects model was used if substantial heterogeneity (I 2 > 50%) was found; otherwise, a fixed-effects model was used.

RESULTS

We found no clinically important difference between minimally invasive and open surgery in terms of the AOFAS score (88 ± 7 versus 85 ± 8, respectively; mean difference 4 points [95% CI 1 to 6]; p < 0.01). There were no differences between the minimally invasive and open surgery groups in terms of VAS scores (0 ± 0 versus 0 ± 1, respectively; standardized mean difference 0 points [95% CI -1 to 0]; p = 0.08). There were no differences between the minimally invasive and open surgery groups in terms of the hallux valgus angle (12° ± 4° versus 12° ± 4°; mean difference 0 points [95% CI -2 to 2]; p = 0.76). Radiographic measurements of the intermetatarsal angle did not differ between the minimally invasive and open surgery groups (7° ± 2° versus 7° ± 2°; mean difference 0 points [95% CI -1 to 1]; p = 0.69). In addition, there were no differences between the minimally invasive and open surgery groups in terms of the distal metatarsal articular angle (7° ± 4° versus 8° ± 4°; mean difference -1 point [95% CI -4 to 2]; p = 0.28). The qualitative analysis revealed no difference in the frequency or severity of complications between the minimally invasive and the open surgery groups. The minimally invasive and open surgery groups did not differ in terms of the duration of surgery (28 ± 8 minutes versus 40 ± 10 minutes; mean difference -12 minutes [95% CI -25 to 1]; p = 0.06).

CONCLUSION

This meta-analysis found that hallux valgus treated with minimally invasive surgery did not result in improved clinical or radiologic outcomes compared with open surgery. Methodologic shortcomings of the source studies in this meta-analysis likely inflated the apparent benefits of minimally invasive surgery, such that in reality it may be inferior to the traditional approach. Given the associated learning curves-during which patients may be harmed by surgeons who are gaining familiarity with a new technique-we are unable to recommend the minimally invasive approach over traditional approaches, in light of the absence of any clinically important benefits identified in this meta-analysis. Future research should ensure studies are methodologically robust using validated clinical and radiologic parameters, as well as patient-reported outcome measures, to assess the long-term outcomes of minimally invasive surgery.

Perspectives and trends for minimally invasive surgery for hallux valgus deformity in the Asia Pacific region

BACKGROUND

Evolving evidence and improved instrumentation have led to increasing importance of minimally invasive surgery (MIS) surgery in the treatment of hallux valgus deformity. This study aims to investigate the current trends of the practice of MIS hallux valgus surgery in the Asia Pacific region.

METHOD

A survey was sent via email to 30 fellowship-trained foot and ankle surgeons in 11 Asia Pacific countries, all registered with their respective national orthopaedic societies. The survey consisted of 8 questions and was designed to assess surgeon experience with MIS hallux valgus surgery, including common contraindications, satisfaction levels, learning curves and post-operative rehabilitation after MIS hallux valgus surgery.

RESULTS

The vast majority of surgeons (63%) performed MIS hallux valgus surgery. However, only 18% of surgeons performed MIS surgery in more than half of their hallux valgus cases. A severe deformity was the most common contraindication (81%), followed by the instability of the first tarsometatarsal joint (50%), and abnormal DMAA (Distal Metatarsal Articular Angle) (38%). There was no statistically significant difference between the satisfaction score of MIS versus open surgery (p-value 0.1). The median number of cases the surgeons needed to perform before they considered themselves comfortable performing the surgery was 10 cases (range 1-100). Most surgeons allowed full weight bearing at 4-6 weeks after surgery.

CONCLUSIONS

MIS hallux valgus surgery is gaining popularity in the Asia Pacific region, with the majority of surgeons adopting this practice. The fact that severe deformity is seen as the most frequent contraindication and that MIS surgery is still not the most popular alternative demonstrates that surgeons are still circumspect when it comes to MIS surgery. Surgeons can use the findings of this study to guide their adoption of MIS practices in hallux valgus surgery and gauge well they perform in comparison to their counterparts in the Asia Pacific region.

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 Foot and Ankle Surgery: A Primer for Orthopaedic Surgeons

There is rapidly growing interest in minimally invasive surgery (MIS) of the foot and ankle. Technological advances, specifically with the advent of low-speed high-torque burrs, have enabled the expansion of MIS techniques. Accordingly, there is growing literature reporting excellent outcomes of MIS surgery to address many different pathologies of the foot and ankle. MIS techniques are particularly useful for conducting percutaneous osteotomies and bony débridement. These can be used to address bunion deformity, hammertoes, metatarsalgia, bunionette deformity, bone spurs, and hindfoot deformity. A detailed understanding of the technology, equipment, and techniques is crucial to safely conduct MIS of the foot and ankle. When done safely, MIS provides favorable outcomes with an expedited recovery and limited complications.

Five-Year Follow-up of Third-Generation Percutaneous Chevron and Akin Osteotomies (PECA) for Hallux Valgus

BACKGROUND

Recent large studies of third-generation minimally invasive hallux valgus surgery (MIS) have demonstrated significant improvement in clinical and radiologic outcomes. It remains unknown whether these clinical and radiologic outcomes are maintained in the medium to long term. The aim of this study was to investigate the minimum 5-year clinical and radiologic outcomes following third-generation MIS hallux valgus surgery in the hands of a high-volume MIS surgeon.

METHODS

A retrospective observational single highly experienced MIS surgeon case series of consecutive patients undergoing primary isolated third-generation percutaneous chevron and Akin osteotomies (PECA) for hallux valgus with a minimum 60-month clinical and radiographic follow-up. Primary outcome was radiographic assessment of the hallux valgus angle (HVA) and intermetatarsal angle (IMA) preoperatively, 6 months, and ≥60 months following PECA. Secondary outcomes included the Manchester-Oxford Foot Questionnaire, patient satisfaction, EuroQol-5D visual analog scale and the visual analog scale for pain.

RESULTS

Between 2012 and 2014, 126 consecutive feet underwent isolated third-generation PECA, with complete data available for 78 (61.9%) feet. The median follow-up was 65.0 (IQR 64-69; range 60-88) months. There was a significant improvement in radiographic deformity correction; the median IMA improved from 12.0 degrees (interquartile range [IQR]: 10.8-14.2) to 6.0 degrees (IQR: 4.2-7.3) (P < .001), and the median HVA improved from 27.2 degrees (IQR: 20.6-34.4) to 7.2 degrees (IQR: 3.4-11.6). Median MOXFQ Index score at ≥60-month follow-up was 2.3 (IQR: 0.0-7.8). The radiographic recurrence rate (defined as HVA >15 degrees) was 7.7% at final follow-up. The complication rate was 4.8%.

CONCLUSION

Radiologic deformity correction for the 78 feet we were able to follow that had third-generation PECA performed by a single highly experienced MIS surgeon was found to be maintained at a mean follow-up of average 66.8 months, with a radiographic recurrence rate of 7.7%. Clinical PROMs and patient satisfaction levels were high and comparable to other third-generation studies with shorter duration of follow-up.

LEVEL OF EVIDENCE

Level IV, retrospective cohort study.

The Learning Curve of Third-Generation Percutaneous Chevron and Akin Osteotomy (PECA) for Hallux Valgus

The learning curve to reach technical proficiency for third-generation percutaneous or minimally invasive chevron and Akin osteotomies (PECA/MICA) is recognized to be steep however it is poorly defined in the literature. This study is a retrospective review of the first 58 consecutive PECA cases of a single surgeon. The primary outcome was the number of cases required to reach technical proficiency as defined by the operation time. Secondary outcomes included radiation exposure, radiographic deformity correction, and complication rates. Between November 2017 and March 2019, 61 consecutive PECA cases were performed with outcome data available for 58 of these (95%). Technical proficiency was reached after 38 cases. Operation time and radiation exposure significantly decreased after this transition point (p < .05). There was no difference in complication rate or radiographic deformity correction regardless of position along the learning curve (p > .05). In conclusion, the mean number of cases required to reach technical proficiency in third-generation PECA is 38 cases. The complication rate does not correlate to the number of cases performed, therefore surgeons interested in learning minimally invasive surgery can be reassured that there is unlikely to be an additional risk of harm to a patient during the learning curve.

The percutaneous learning curve of 3rd generation minimally-invasive Chevron and Akin osteotomy (MICA)

BACKGROUND

Minimally-invasive Chevron and Akin osteotomy (MICA) represents the third-generation percutaneous hallux valgus surgery which is characterized by an extra-articular osteotomy, stable internal fixation and a high potential for correction. Compared to other percutaneous techniques of the foot, MICA is generally regarded as an advanced and demanding surgical procedure with a flat learning curve. The aim of this study is to analyze a single-surgeons experience with his first 50 consecutive MICA procedures.

METHODS

Between May 2018 and February 2021, 50 consecutive MICA procedures performed by the author with the "K-wires-First technique" were prospectively analyzed focusing on surgery duration, number of fluoroscopies, correction results and surgery-associated complications. A modification of the original MICA technique as described by its inaugurators Redfern and Vernois allows the use of a standard-sized C-arm and aims to reduce revison rates and conversion to open surgery by placing the guidewires prior to performing the osteotomy.

RESULTS

The average surgery time for all MICA procedures was 46.8 min (SD 12.1, range 31-90 min). The average amount of fluoro shots required to perform MICA was n = 126.6 (SD 40.8, range 65-231). Comparing the preoperative and 6-week postoperative radiographs, the IMA decreased after MICA by a mean of 10.8° from 16.2° to 5.4° and the HVA by a mean of 22.1° from 30.6° to 8.5°. One case required intraoperative conversion to open hallux correction. There were 4 feet in three patients with secondary screw removal of the Chevron fixation due to prominent proximal screw tips.

CONCLUSIONS

Although the learning curve of 3rd generation MICA is flat and requires specific training and intensive practice, the rate of complications is not elevated compared to other percutaneous hallux valgus techniques. Strict adherence to the principles of 3rd generation MICA with stable fixation and meticulous intraoperative control of each surgical step helps to reduce surgery-associated complications. The learning curve showed a continous improvement in regard to surgery time and use of fluoroscopy. After 40 procedures, the surgery time consistently dropped under 45 min and required less than 100 fluoro-shots. The modified surgical technique may help reduce Chevron screw mal-positioning when using large C-arm fluoroscopy for this procedure.

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

BACKGROUND

The minimally invasive chevron-Akin (MICA) technique has already demonstrated efficacy compared with other known surgical treatments for mild to moderate hallux valgus (HV). MICA combines percutaneous osteotomies with the benefits of modern, rigid internal fixation. The aim of study was to evaluate the radiographic parameters, clinical improvement, and potential complications in moderate to severe HV cases, operated using the MICA technique.

METHODS

Retrospective study including 70 feet with HV operated using the MICA technique. The AOFAS hallux MTP-IP score and radiographics for HV evaluation were applied preoperatively, and after 6 months, 1 year, and 2 years of follow-up. The following radiographic parameters were measured: metatarsophalangeal hallux valgus angle (HVA), distal metatarsal articular angle (DMAA), interphalangeal angle (IPA), and intermetatarsal angle (IMA).

RESULTS

The average preoperative VAS pain score was 8.2 ± 1.5, which improved to 1.2 ± 2.2 at 24 months. The mean preoperative IMA was 14.8 ± 3.6 degrees compared with a mean of 7.5 ± 2.1 degrees (P < .01) at 24 months. The preoperative HVA value averaged 30.4 ± 9.8 degrees and at 6 months postoperatively 11.1 ± 6.8 degrees (P < .01), which remained stable until measured at 24 months. The mean preoperative DMAA was 16.3 ± 8.6 degrees and at the 6-month follow-up was 7.8 ± 5.4 degrees (P < .01). The mean preoperative IPA was 7.63 ± 4.4 degrees compared with a mean of 6.28 ± 3.5 degrees (P > .05) at 24 months. Complications included painful hardware (14.28%), neuropathic pain (2.85%), and loss of correction (4.28%).

CONCLUSION

In this retrospective review from a single center, we found the MICA technique to be an effective procedure for correcting moderate to severe HV, with a low rate of recurrence and an acceptable rate of complications. Patients undergoing the surgical procedure in our series showed a significant reduction in radiographic parameters and a significant improvement in clinical scores, maintaining these results over time.

LEVEL OF EVIDENCE

Level IV, retrospective study.

Treating Hallux Valgus Associated Metatarsus Adductus by Minimally Invasive Surgery: A Simple Solution for a Difficult Problem

This study aims to assess a novel minimally invasive surgical technique that addresses hallux valgus accompanied by metatarsus adductus. We retrospectively analysed the results of 20 patients (21 feet) that underwent a newly developed percutaneous osteotomy procedure of the lesser metatarsal bones in order to correct hallux valgus deformities accompanied by metatarsus adductus. We used x-ray studies in order to evaluate changes in the hallux valgus angle, the first intermetatarsal angle, and the metatarsal angle (using the modified Sgarlato method). We also compared the pre- and postoperative American Orthopaedic Foot and Ankle Society scores when available. The paired sample t test was used to compare variables. At a 1-y follow-up the mean hallux valgus angle, inter-metatarsal angle and the metatarsal angle have been reduced by 31.62 (-3 to 9), 3.86 (11-52) and 14.69 (4-36) respectively (p < .001 for all). The mean American Orthopaedic Foot and Ankle Society score (n = 15 feet available) has been improved by a mean of 44.53 (22-72, p < .001). In addition, the patient satisfaction rates were high. Patients suffered from mild to moderate midfoot pain during the first few weeks following surgery, which resolved when union occurred. No cases of lesser metatarsal nonunion have been documented. The presented minimally invasive method can be used effectively to correct hallux valgus that is associated with metatarsus adductus. Proximal minimally invasive metatarsal osteotomy can effectively correct hallux valgus accompanied by metatarsus adductus.

Modified Bösch Osteotomy Combined With a Percutaneous Adductor Tendon Release for the Treatment of Hallux Valgus Deformity: Learning Curve

PURPOSE

The expression "learning curve" indicates the relation between the time needed to learn a new technique and the technique-related outcome. Percutaneous surgery (also called "minimally invasive surgery") has experienced sustained and respectable growth, especially in forefoot deformities. The main purpose was to assess the number of feet necessary to become skilled in a specific minimally invasive surgery (MIS) procedure.

METHODS

From January 2015 to June 2018, 46 consecutive patients were evaluated and included in the study. Patients were divided into 2 groups according to the surgery period: first 30 feet (Group 1), and subsequent 30 feet (Group 2) from the whole population evaluated. Age, body mass index, and operative time were evaluated. Hallux valgus angle and the 1 to 2 intermetatarsal angle were also measured. Patients were assessed according to the American Orthopedic Foot and Ankle Society (AOFAS) forefoot scale, the Foot and Ankle Ability Measure activities of daily living (FAAM ADL) subscale and the visual analog scale (VAS).

RESULTS

The comparison of the 2 groups showed statistically significant differences in hallux valgus angle (HVA) but not in intermetatarsal angle (IMA). The mean improvement between pre- and postoperative FAAM ADL, VAS, and AOFAS score in Group 1 were 12.83, 3.93, and 24.77 points, respectively. In Group 2, the mean improvement between pre- and postoperative FAAM ADL, VAS, and AOFAS scores were 15.19, 4.3, and 24.5 points, respectively. The differences between groups in FAAM ADL score was statistically significant (P = 0.0364). Group 1 showed a global complication rate of 16.67% (n = 5) while group 2 showed 3,3% (n = 1).

CONCLUSION

After the first 30 cases, radiographic, clinical, and functional outcomes substantially improved, and the level of the perioperative complications decreased. The results suggest that the learning curve plateau for performing a percutaneous subcapital osteotomy can be reached after 30 surgeries.

LEVELS OF EVIDENCE

Level III.

3rd generation MICA with the "K-wires-first technique" - a step-by-step instruction and preliminary results

BACKGROUND

Minimally-invasive techniques for hallux valgus correction are becoming increasingly popular. In the last decades, multiple techniques for minimally-invasive hallux valgus correction have been described. MICA (Minimally-invasive Chevron & Akin), representing the 3rd generation of minimally-invasive hallux valgus correction, combines the advantages of an extraarticular osteotomy, stable internal fixation, and high potential for correction. This report aims to provide a step-by-step instruction of the surgical technique with the "K-wires-first" MICA modification, illustrated by detailed imaging of both intraoperative fluoroscopy and clinical imaging as well as corresponding sawbone models for each step. Preliminary results including radiological outcome and complications of the first 50 cases will be discussed.

METHODS

Between May 2018 and May 2021, 50 consecutive MICAs in 47 patients were performed with the K-wires-first technique. There were 40 women and 7 men with an average of 57.4y (range 25-78). The mean preoperative IMA was 16.2° (range 11.0-21.5), the HVA 30.6° (range 21.8-42.1).

RESULTS

There was one intraoperative conversion to an open surgical bunion correction corresponding to a 2% conversion rate respectively (1/50). On 3 feet (2 patients), removal of the Chevron screws was performed after 7, 9, and 12 months due to prominent and disturbing screw heads at the level of the medial cortex, accounting for a revision rate of 6% (3/50). There were no other secondary revision surgeries. The IMA decreased after MICA by a mean of 10.8° from 16.2° to 5.4° and the HVA by a mean of 22.1° from 30.6° to 8.5°, demonstrating MICA's high potential for correction.

CONCLUSIONS

Compared to other MICA techniques, the K-wires-first modification helps to reduce hardware malpositioning and the risk of conversion to open surgery. Furthermore, our preliminary results demonstrate a high potential for correction even for severe hallux deformities.

TRIAL REGISTRATION

Retrospectively registered, swissethics BASEC-ID 2021-01537, July 16th, 2021 ( www.raps.swissethics.ch ).

Percutaneous, intra-articular, chevron osteotomy (PeICO) for the treatment of mild-to-moderate hallux valgus: a case series

PURPOSE

Treatment for hallux valgus (HV) remains challenging. Third-generation percutaneous procedures try to reproduce chevron-type osteotomies to replicate their benefits, such as intrinsic stability and reproducibility. We report the first results using a percutaneous, intra-articular, chevron osteotomy (PeICO) technique that mimics the classic intra-articular open chevron procedure, associated with a percutaneous adductor tendon release (PATR) for the treatment of mild-to-moderate HV.

METHODS

From May 2015 to October 2018, a total of consecutive 114 feet (74 patients) were included. Primary outcome measures included radiographic (hallux valgus and intermetatarsal angles) and clinical parameters such as visual analog scale (VAS), FAAM Activities of Daily Living (ADL), and FAAM Sport, AOFAS Score, and MOXFQ, preoperatively and at final follow-up (Minimum 18 months). A patient satisfaction survey was also performed. Pronation and length of the first metatarsal were also assessed. Secondary outcomes included fluoroscopic time, length of surgery, complications, recurrence, and re-operation rates.

RESULTS

At 24.09 months on average, the AOFAS score improved from 52.1 points preoperatively to 91.1 (p < 0.001) at the latest follow-up. VAS decreased from 6.3 to 1. Also, FAAM ALD, FAAM Sport, and MOXFQ showed statistically significant differences (p < 0.001) when comparing pre-operative and post-operative periods. Patients found the procedure to be excellent in 82% and very good in 13.5% of cases. Our global complication and re-operation rates were 5.26% and 3.5% (screw removal), respectively.

CONCLUSION

PeICO combined with PATR proved to be a safe, reliable, and effective technique for the correction of mild-to-moderate HV deformity.

Third-Generation Minimally Invasive Chevron and Akin Osteotomies (MICA) in Hallux Valgus Surgery: Two-Year Follow-up of 292 Cases

BACKGROUND

There is interest in hallux valgus deformity correction using internal fixation with the minimally invasive chevron and Akin osteotomies (MICA) technique. The objective of this study was to assess the correction measured on postoperative radiographs and clinical outcomes, using validated outcome measures, at 2 years following third-generation MICA.

METHODS

This is a prospective single-surgeon case series of 333 consecutive feet that underwent MICA surgery between July 2014 and April 2018. The primary clinical outcome measures included the Manchester-Oxford Foot Questionnaire (MOXFQ), EuroQol-5 Dimensions-5 Level (EQ-5D-5L) Index, EuroQol-visual analogue scale (EQ-VAS), and a VAS for pain (VAS-pain). Secondary outcome measures included radiographic parameters and complication rates.

RESULTS

Preoperative and 2-year postoperative patient-reported outcome measures (PROMs) were collected for 292 feet (87.7%). At a minimum 2-year follow-up, the MOXFQ scores (mean ± standard deviation [SD]) had improved in each domain-i.e., reduced from 44.5 ± 21.0 preoperatively to 9.4 ± 15.8 postoperatively for pain (p < 0.001), from 38.7 ± 23.4 to 6.5 ± 14.6 for walking and standing (p < 0.001), and from 48.0 ± 22.3 to 6.6 ± 13.5 for social interaction (p < 0.001). The VAS-pain score improved from 31.4 ± 22.7 preoperatively to 8.4 ± 16.4 at the 2-year follow-up (p < 0.001), the 1-2 intermetatarsal angle was reduced from 15.3° ± 3.6° preoperatively to 5.7° ± 3.2° at the 2-year follow-up (p < 0.001), and the hallux valgus angle was reduced from 32.9° ± 10.2° to 8.7° ± 5.2° (p < 0.001).

CONCLUSIONS

The third-generation MICA provided significant improvement in clinical outcome measures at the 2-year follow-up and can be successfully used for correction of a range of hallux valgus deformities with a low rate of symptomatic recurrence.

LEVEL OF EVIDENCE

Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.