Three-Dimensional Analysis of the First Metatarsal Bone in Minimally Invasive Distal Linear Metatarsal Osteotomy for Hallux Valgus

First Metatarsal Rotation After Scarf Osteotomy for Hallux Valgus

BACKGROUND

Recurrence after surgical correction of hallux valgus may be related to coronal rotation of the first metatarsal. The scarf osteotomy is a commonly used procedure for correcting hallux valgus but has limited ability to correct rotation. Using weight-bearing computed tomography (WBCT), we aimed to measure the coronal rotation of the first metatarsal before and after a scarf osteotomy, and correlate these to clinical outcome scores.

METHODS

We retrospectively analyzed 16 feet (15 patients) who had a WBCT before and after scarf osteotomy for hallux valgus correction. On both scans, hallux valgus angle (HVA), intermetatarsal angle (IMA), and anteroposterior/lateral talus-first metatarsal angle were measured using digitally reconstructed radiographs. Metatarsal pronation angle (MPA), alpha angle, sesamoid rotation angle, and sesamoid position were measured on standardized coronal WBCT slices. Preoperative and postoperative (12 mo) clinical outcome scores (Manchester Oxford Foot Questionnaire and Visual Analogue Scores) were captured.

RESULTS

Mean HVA was 28.6 ± 10.1° preoperatively and 12.1 ± 7.7° postoperatively (P < .001). Mean IMA was 13.7 ± 3.8° preoperatively and 7.5 ± 3.0° postoperatively (P < .001). Before and after surgery, there were no significant differences in MPA (11.4 ± 7.7 and 11.4 ± 9.9°, respectively; P = .75) or alpha angle (10.9 ± 8.0 and 10.7 ± 13.1°, respectively; P = .83). There were significant improvements in sesamoid rotation angle (SRA) (26.4 ± 10.2 and 15.7 ± 10.2°, respectively; P = .03) and sesamoid position (1.4 ± 1.0 and 0.6 ± 0.6, respectively; P = .04) after a scarf osteotomy. There were significant improvements in all outcome scores after surgery. Poorer outcome scores correlated with greater postoperative MPA and alpha angles (r = .76 (P = .02) and .67 (P = .03), respectively).

CONCLUSION

A scarf osteotomy does not correct first metatarsal coronal rotation, and worse outcomes are linked to greater postoperative metatarsal rotation. Rotation of the metatarsal needs to be measured and considered when planning hallux valgus surgery. Further work was needed to compare postoperative outcomes with rotational osteotomies and modified Lapidus procedures when addressing rotation.Level of Evidence: 4.

Lower limb kinematic changes during gait after hallux valgus surgery: A prospective observational study

BACKGROUND

Patients with hallux valgus are known to alter lower limb joint kinematics during gait. However, little information is available about gait changes following hallux valgus surgery. We aimed to longitudinally investigate lower limb kinematic changes at the mid and terminal stances of gait after hallux valgus surgery.

METHODS

This prospective observational study included 11 female patients (17 feet), who underwent first metatarsal osteotomy. Gait analyses were performed preoperatively and 1- and 2-year postoperatively using a three-dimensional motion capture system. Toe-out angle, ankle, knee, and hip joint angles during gait were calculated from the recorded data. The spatiotemporal parameters and these angles at the mid and terminal stances of gait were statistically compared between preoperative and postoperative periods.

FINDINGS

All spatiotemporal parameters remained unchanged postoperatively. The toe-out angle was significantly greater at 1- and 2-year postoperatively. The ankle pronation angle, the knee abduction angle, and the hip adduction angle at the mid and terminal stances of gait were smaller postoperatively compared to the preoperative. These angular changes showed a similar trend at 1 and 2 years postoperatively. However, the postoperative changes of the sagittal joint angles were relatively small.

INTERPRETATION

Hallux valgus surgery can affect the toe-out angle and the lower limb coronal kinematics at the mid and terminal stances of gait in patients with hallux valgus. However, surgical correction of hallux valgus deformity did not directly improve the gait characteristics in patients with hallux valgus.

Forefoot Function after Hallux Valgus Surgery: A Systematic Review and Meta-Analysis on Plantar Load Measurement

While hallux valgus (HV) surgeries are useful for correcting skeletal alignment problems, their effects on plantar load, which reflects forefoot functions, are less understood. The objective of this study is to conduct a systematic review and meta-analysis on the plantar load change after HV surgeries. A systematic search of Web of Science, Scopus, PubMed, CENTRAL, EMBASE, and CINAHL was performed. Studies that assessed the pre- and post-operative plantar pressure of HV patients undergoing surgeries and reported load-related parameters over the hallux, medial metatarsal, and/or central metatarsal regions were included. Studies were appraised by using the modified NIH quality assessment tool for before-after study. Studies suitable for meta-analysis were pooled with the random-effects model, using the standardized mean difference of the before-after parameters as an effect measure. Twenty-six studies containing 857 HV patients and 973 feet were included for the systematic review. Meta-analysis was conducted on 20 of them, and most studies did not favor HV surgeries. Overall, HV surgeries reduced the plantar load over the hallux region (SMD -0.71, 95% CI, -1.15 to -0.26), indicating that forefoot function worsened after surgeries. For the other five outcomes, the overall estimates were not statistically significant, indicating that surgeries did not improve them either. There was substantial heterogeneity among the studies, which in most cases could not be resolved by pre-planned subgroup analyses by surgical classification, year of publication, median age of patients, and length of follow-up. Sensitivity analysis removing lower-quality studies showed that the load integrals (impulse) over the central metatarsal region significantly increased (SMD 0.27, 95% CI, 0 to 0.53), indicating that surgeries increased the risk of transfer metatarsalgia. There is no solid evidence that HV surgeries could improve forefoot functions from a biomechanical point perspective. Currently available evidence even suggests that surgeries might reduce the plantar load over the hallux and adversely affect push-off function. The reasons behind and the effectiveness of alternative surgical methods warrant further investigation.

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.

Bilateral and concomitant pathology' surgeries do not affect the outcomes of mini-open distal linear metatarsal osteotomy (Bosch osteotomy) with manipulation for hallux valgus deformity

BACKGROUND

Bosch osteotomy for hallux valgus (HV) deformity has advantages of reduction both the operating time and surgical dissection, and may be performed bilaterally and with fewer complications than other surgical procedures as well as early weight-bearing. However, there are few reports on the effects of bilateral simultaneous surgery, simultaneous surgery on concomitant pathologies, and the preoperative HV angle on the postoperative results. The present assessed the factors that might affect the improvement in clinical outcomes following mini-open Bosch osteotomy with manipulation to treat HV deformity.

METHODS

Seventy patients with 110 feet were included. They were divided into groups as follows: unilateral and bilateral simultaneous surgery groups, Bosch osteotomy alone and simultaneous surgeries for concomitant pathologies groups, and preoperative HV angle< 40° and ≥ 40° groups. Subjective clinical outcome scores using the Self-Administered Foot Evaluation Questionnaire (SAFE-Q) and the HV and intermetatarsal first and second metatarsal (M1M2) angles according to the anteroposterior (A-P) view of the weighted foot X-ray were assessed preoperatively and at 12 months after surgery.

RESULTS

The mean HV angle, M1M2 angle and all subscales of the SAFE-Q score showed significant improvement at 12 months after surgery, regardless of simultaneous bilateral surgery, simultaneous surgery for concomitant pathologies, or the preoperative HV angle. On comparing the groups, there were no significant differences in the HV angle at 12 months after surgery. Significant inferiority at 12 months after surgery was found in the intermetatarsal angle in the simultaneous surgery for concomitant pathologies group and in all subscales of the SAFE-Q score in the HV angle ≥ 40° group.

CONCLUSION

Mini-open Bosch osteotomy with manipulation for HV deformity demonstrated good results in both radiological assessments and subjective clinical scores at 12 months after surgery, even for simultaneous bilateral surgery, simultaneous concomitant pathologies' surgery, and severe HV deformity.

LEVEL OF EVIDENCE

Prognostic Level III, retrospective cohort study.

Radiographic and clinical outcomes of minimally invasive surgery versus open osteotomies for the correction of hallux valgus

PURPOSE

Hallux valgus is a common disease which causes pain and dysfunction of the foot. Although numerous methods of procedures have been introduced, a single procedure cannot correct all deformities of hallux valgus. The study aims to evaluate the radiographic and clinical effectiveness of a new minimally invasive surgery (MIS) versus open Chevron-Akin procedures.

METHODS

This was a retrospective comparative study. Data were collected from May 2018 to January 2020. A total of 27 patients (31 feet) undergoing MIS for hallux valgus were included in this study. The average age of patients underwent MIS was 59.9 years. The mean follow-up was 25.1 months. Open osteotomies were performed in 30 patients (31 feet) during the same period. The mean age of these patients at the time of surgery was 59.1 years. The mean follow-up was 26.1 months. Pre-operative and post-operative radiographic outcome measures included HVA, IMA, DMAA, the Sgarlato's angle and the length of the first metatarsal, and distance between the dorsal cortex of first and second metatarsal necks. The AOFAS and VAS were used to assess foot function.

RESULTS

The preoperative HVA in MIS group and open group were 34.8° and 33.1° respectively. The post-operative HVA were 20.4° and 13.7°. The pre-operative IMA in MIS group and open group were 13.0° and 12.1°. The post-operative IMA were 11.4° and 5.5° respectively. The pre-operative DMAA were 14.8° and 15.1° respectively. The post-operative DMAA were 6.3° and 8.7°. The AOFAS increased from 44.0 to 90.2 in MIS group and from 47.6 to 89.5 in open group. The VAS decreased from 7.3 to 1.3 in MIS group and from 7.1 to 1.2 in open group.

CONCLUSION

Although open osteotomies were superior than MIS in HVA and IMA, MIS showed advantages in correcting DMAA. MIS provided equivalent functional outcomes compared to open surgery.

Imaging Findings and First Metatarsal Rotation in Hallux Valgus

BACKGROUND

Failure to identify and correct malrotation of the first metatarsal may lead to recurrent hallux valgus deformity. We aimed to identify the proportion of hallux valgus patients with increased first metatarsal pronation using weightbearing computed tomography (WBCT) and to identify the relationship with conventional radiographic measurements.

METHODS

WBCT scans were analyzed for 102 feet with a hallux valgus angle (HVA) and intermetatarsal angle (IMA) greater than or equal to 16 and 9 degrees, respectively. Metatarsal pronation angle (MPA), alpha angle, sesamoid rotation angle (SRA), and sesamoid position were measured on standardized coronal WBCT slices. Pronation was recorded as positive. Hindfoot alignment angle (HAA) was assessed using dedicated software. Pearson correlation and multiple regression analyses were used to assess differences between groups.

RESULTS

Mean HVA was 29.8±9.4 degrees and mean IMA was 14.1±3.7 degrees. Mean MPA was 11.9±5.8 (range 0-26) degrees and mean alpha angle was 11.9±6.8 (range -3 to 29) degrees. In a previous study, we demonstrated the upper limit of normal MPA as 16 degrees and alpha angle as 18 degrees. Based on these criteria, we identified abnormal metatarsal pronation in 32 feet (31.4%). We found a strong positive correlation between SRA and HVA/IMA (R = 0.67/0.60, respectively, P < .001). IMA and HAA weakly correlated with MPA and alpha angle (IMA: R = 0.26/0.27, respectively, P < .01; HAA: R = 0.26/0.27, respectively, P < .01). Regression analyses suggested that increasing IMA was the most significant radiographic predictor of increased pronation. In this cohort, there was no correlation between HVA or sesamoid position and MPA / alpha angle (HVA: P = .36/.12, respectively, sesamoid position, P = .86/.77, respectively).

CONCLUSION

In this cohort of 102 feet that met plain radiographic criteria for hallux valgus deformity, first metatarsal pronation was found abnormal in 31.4% of patients. We found a weak association between the IMA and hindfoot valgus, but not the HVA.

Assessing the Rotation of the First Metatarsal on Computed Tomography Scans: A Systematic Literature Review

BACKGROUND

Hallux valgus is a multiplanar deformity that is often treated on the basis of 2-dimensional (2D) parameters and radiographs. Recurrence rates after surgical correction remain high, and failure to correct pronation of the metatarsal is increasingly stipulated as being part of the problem. Multiple methods of assessing metatarsal pronation have been proposed.

METHODS

We performed a systematic literature review identifying studies that measured metatarsal pronation and torsion on computed tomography (CT) scans. Specific methodology, patient groups, results, and reliability assessments were all reported.

RESULTS

We identified 14 studies that fulfilled the inclusion criteria. Eleven studies measured 2D values on CT scan, and 3 studies used computer-based 3-dimensional (3D) modeling and artificial intelligence systems to help calculate pronation. Metatarsal pronation angle, α angle, sesamoid rotation angle, and measurements for torsion were the most commonly used methods. All angles and measurements were performed as 2D measurements, but the metatarsal pronation angle was also performed with 3D modeling. Reliability and reproducibility of the α angle and metatarsal pronation angle were excellent, despite being performed on studies with small numbers.

CONCLUSION

Multiple methods have been reported to demonstrate first metatarsal pronation on CT, of which the α angle and the metatarsal pronation angle are the most pragmatic and useful in a clinical setting. Further work is needed to further validate the reliability of these measurements in larger series and to identify normal pronation and metatarsal torsion on weightbearing imaging. Further work is required to determine whether addressing pronation reduces recurrence rates and improves outcomes in surgery for hallux valgus.

LEVEL OF EVIDENCE

Level III, retrospective cohort study.

The Assessment of First Metatarsal Rotation in the Normal Adult Population Using Weightbearing Computed Tomography

BACKGROUND

The importance of the rotational profile of the first metatarsal is increasingly recognized in the surgical planning of hallux valgus. However, rotation in the normal population has only been measured in small series. We aimed to identify the normal range of first metatarsal rotation in a large series using weightbearing computed tomography (WBCT).

METHODS

WBCT scans were retrospectively analyzed for 182 normal feet (91 patients). Hallux valgus angle, intermetatarsal angle, anteroposterior/lateral talus-first metatarsal angle, calcaneal pitch, and hindfoot alignment angle were measured using digitally reconstructed radiographs. Patients with abnormal values for any of these measures and those with concomitant pathology, previous surgery, or hallux rigidus were excluded. Final assessment was performed on 126 feet. Metatarsal pronation (MPA) and α angles were measured on standardized coronal computed tomography slices. Pronation was recorded as positive. Intraobserver and interobserver reliability were assessed using intraclass correlation coefficients (ICCs).

RESULTS

Mean MPA was 5.5 ± 5.1 (range, -6 to 25) degrees, and mean α angle was 6.9 ± 5.5 (range, -5 to 22) degrees. When considering the normal range as within 2 standard deviations of the mean, the normal range identified was -5 to 16 degrees for MPA and -4 to 18 degrees for α angle. Interobserver and intraobserver reliability were excellent for both MPA (ICC = 0.80 and 0.97, respectively) and α angle (ICC = 0.83 and 0.95, respectively). There was a moderate positive correlation between MPA and α angle (Pearson coefficient 0.68, P < .001).

CONCLUSION

Metatarsal rotation is variable in normal feet. Normal MPA can be defined as less than 16 degrees, and normal α angle can be defined as less than 18 degrees. Both MPA and α angle are reproducible methods for assessing rotation. Further work is needed to evaluate these angles in patients with deformity and to determine their significance when planning surgical correction of hallux valgus.

LEVEL OF EVIDENCE

Level III, retrospective comparative study.

First Metatarsal Rotation in Hallux Valgus Deformity

Rotation of the first metatarsal (M1) as a potential etiological factor of hallux valgus (HV) deformity was described relatively early in the description of HV pathoanatomy. However, because biplanar radiographs have been the standard method for imaging HV, clinicians primarily developed measurement methods and corrective operations confined to 2 dimensions, medial-lateral and inferior-superior. Recently, as our understanding of HV pathoanatomy has further developed, aided in part by advanced imaging technology, M1 rotation about its axis ("axial rotation") and its implications for HV deformity and treatment has reemerged. The goal of this review is to summarize M1 rotation in HV from a historical perspective, to present the current understanding of its potential role in the etiology/pathogenesis of HV, and to summarize relevant imaging and operative considerations with respect to M1 rotation.Level of Evidence: Level III, systematic review.

Analysis of Shortening and Elevation of the First Ray With Instrumented Triplane First Tarsometatarsal Arthrodesis

BACKGROUND

The Lapidus procedure using planar saw resection has often been criticized for complications related to excessive shortening and elevation of the first ray. The goal of this study was to assess the amount of shortening that occurs when using a cutting guide for controlled saw resection of the first tarsometatarsal (TMT) joint surfaces, along with assessment of deformity correction in all 3 anatomic planes.

METHODS

A prospective multicenter study with IRB approval included 35 hallux valgus subjects evaluated at baseline and 6 months following instrumented triplane first TMT arthrodesis without lesser metatarsal osteotomies.

RESULTS

The average first ray bone segment length loss was 3.1 mm (95% confidence interval [CI] 2.4-3.7) in the anteroposterior (AP) radiographic assessment and 2.4 mm (95% CI 1.7-3.1) in the sagittal plane. The mean preoperative radiographic measurements were 1.7 degrees (dorsiflexion) for sagittal plane angle, 13.8 degrees for intermetatarsal angle (IMA), and 5.1 for tibial sesamoid position (TSP). Improvements were seen postoperatively for all measures with a mean difference of -0.2 degrees (95% CI -1.0 to 0.6) for sagittal plane angle, -9.2 degrees (95% CI -10.1 to -8.3 degrees) for IMA, and -3.5 (95% CI -4.0 to -3.1) for TSP. Five of the patients reported lesser metatarsal pain preoperatively, and no patients complained of lesser metatarsalgia at 6-month follow-up.

CONCLUSIONS

Minimal length loss of the first ray can be expected following instrumented triplane TMT arthrodesis while achieving full 3-dimensional deformity correction and reducing the risk of lesser metatarsalgia.

LEVEL OF EVIDENCE

Level II, prospective comparative study.