The Use of a Triplanar Metatarsal Rotational Osteotomy to Correct Hallux Valgus Deformities

Decision-making in Hallux Valgus Correction

Hallux valgus deformity is the most common surgical indication in the foot. The achievable result is highly dependent on preoperative planning and the choice of surgical procedure. Consideration of anatomic specifications, angulation at the MTP and intermetatarsal 1/2 (IMT), and joint status at the metatarsophalangeal and TMT joints provide the basis for this. Minor, moderate, and severe deformities can be assigned to different osteotomy heights and, within these, a surgical procedure. Each method, if applied appropriately, is suitable and its correct use allows simple operations with maximum success.

Clinical and Radiographic Outcomes of Percutaneous Third-Generation Double First Metatarsal Osteotomy Combined With Closing-Wedge Proximal Phalangeal Osteotomy for Moderate and Severe Hallux Valgus

BACKGROUND

The treatment for severe hallux valgus deformity presents a challenge with high risk of complications. Third generation MIS techniques have increased their publications in recent years. The aim was to compare clinical and radiologic outcomes in moderate and severe cases and report minor and major complications.

METHODS

Retrospective series of cases with prospective data collection of 156 consecutive feet that underwent percutaneous double first metatarsal osteotomy (PEDO) and first phalanx osteotomy between 2008 and 2019 for moderate (hallux valgus angle [HVA] between ≥20 and <40 degrees and/or intermetatarsal angle [IMA] <16 degrees) and severe (HVA ≥40 degrees and/or IMA ≥16 degrees) hallux valgus deformities. Primary outcomes included radiographic and clinical parameters. Secondary outcomes included minor and major complications.

RESULTS

A total of 156 procedures were performed in 128 patients. Mean age was 54.3 years (SD 14.3) (range, 19-82 years), median follow-up was 22.6 months (range, 12-96 months). Radiographic changes pre- to postoperation were as follows: HVA changed from 38.2 (SD 10.1) degrees to 11.2 (SD 8.3) degrees (P < .001), IMA from 14.7 (SD 3.2) degrees to 7.9 (SD 3.7) degrees (P < .001), and distal articular metatarsal angle from 19.7 (SD 6.3) degrees to 8.8 (SD 5.7) degrees (P < .001) after PEDO technique. Clinical changes pre- to postoperation were as follows: American Orthopaedic Foot & Ankle Society ankle-hindfoot scale scores improved from 47.3 (SD 16.5) to 87 (SD 11.6) (P < .001) and visual analog scale scores from 5 (2.7) to 0.9 (1.3) (P < .001). The satisfaction rate was 97% in the total sample. Recurrence rate (HVA ≥20 degrees) was 7.7%. Hallux varus (HVA <0 degrees) occurred in 5.8%, acute osteomyelitis in 1.3%, partial avascular necrosis in 0.6%, screw removal in 0.6%, and reoperation in 1.9%. No nonunion was observed.

CONCLUSION

Clinical and radiographic parameters improved significantly, with a minimum of 12 months of follow-up in moderate and severe hallux valgus. Long experience in percutaneous surgery and specific instruments are needed for this technique. Recurrence was linked to preoperative HVA ≥40 degrees and postoperative tibial sesamoid position; Hallux varus was linked to lateral soft tissue release.

LEVEL OF EVIDENCE

Level IV, case series.

Intra‑ and Interobserver Reliability of Yamaguchi's Method for the Assessment of First Metatarsal Pronation in Hallux Valgus Deformity

Pronation of the first metatarsal is a risk factor for the formation and progression of the hallux valgus deformity. Recently, Yamaguchi et al published a study that showed how the round sign increases on digitally reconstructed radiography taken from a CT scan when pronation is applied. In this study, the shape of the lateral edge of the first metatarsal head was evaluated on weightbearing dorsoplantar radiographs. Yamaguchi's signs were presented to observers after the visual presentation of each foot as an image. The best-fit circle was drawn using the PACS drawing function. Ninety radiographs of adults presenting hallux valgus deformities were classified as mild-to-moderate, based on hallux valgus angle and intermetatarsal angle. The global average observations were 3.72 ± 3.92 (range 2.3°-4.6°). The interclass correlation (Fleiss Kappa index κ = 0.225) and the Spearman correlation (0.16 of Kappa) coefficients were poor for interobserver measurements and statistically significant. Using the linear model, there was no significant variability between the repetitions corresponding to each observer (t-value -1.527, p value .127). Our findings show that the Yamaguchi method can be very subjective and should not be the exclusive technique to assess the rotation of the first metatarsal or head roundness.

Association of First Metatarsal Pronation Correction With Patient-Reported Outcomes and Recurrence Rates in Hallux Valgus

BACKGROUND

The purpose of this study was to determine if a postoperative decrease in first metatarsal pronation on 3-dimensional imaging was associated with changes in patient-reported outcomes as measured by the Patient-Reported Outcomes Measurement Information System (PROMIS) physical function, pain interference, and pain intensity domains or recurrence rates in patients with hallux valgus (HV) who undergo a first tarsometatarsal fusion (modified Lapidus procedure).

METHODS

Thirty-nine consecutive HV patients who met the inclusion criteria and underwent a modified Lapidus procedure had preoperative and ≥2-year postoperative PROMIS scores and had first metatarsal pronation measured on preoperative and at least 5-month postoperative weightbearing CT scans were included. Multivariable regression analyses were used to investigate differences in the change in PROMIS domains preoperatively and 2 years postoperatively between patients with "no change/increased first metatarsal pronation" and "decreased first metatarsal pronation." A log-binomial regression analysis was performed to identify if a decrease in first metatarsal pronation was associated with recurrence of the HV deformity.

RESULTS

The decreased first metatarsal pronation group had a significantly greater improvement in the PROMIS physical function scale by 7.2 points (P = .007) compared with the no change/increased first metatarsal pronation group. Recurrence rates were significantly lower in the decreased first metatarsal pronation group when compared to the no change/increased first metatarsal pronation group (risk ratio 0.25, P = .025).

CONCLUSION

Detailed review of this limited cohort of patients who underwent a modified Lapidus procedure suggests that the rotational component of the HV deformity may play an important role in outcomes and recurrence rates following the modified Lapidus procedure.

LEVEL OF EVIDENCE

Level III, retrospective cohort study.

Correlation between indirect radiographic parameters of first metatarsal rotation in hallux valgus and values on weight-bearing computed tomography

PURPOSE

To verify if indirect radiographic signs of first metatarsal pronation, determined by the head round sign, correspond to weight-bearing computed tomography (WBCT) measurements.

METHODS

In this case-control retrospective study, we analyzed 26 hallux valgus (HV) feet and 20 controls through conventional radiograph (CR) and WBCT images. Two blinded orthopaedic foot and ankle surgeons performed the measurements. Pronation classification (head roundness), head diameter (HD), traditional HV angles, arthritis, sesamoid positioning, and first metatarsal rotation angle (MRA) (alpha angle) were evaluated. Comparisons were performed by Student's T-test and a multivariate regression was executed. P-values less than 0.05 were considered significant.

RESULTS

Mean values were higher in HV patients than controls when evaluating MRA (11.51 [9.42-13.60] to 4.23 [1.84-6.62], 95%CI), HD (22.35 [21.52-23.18] to 21.01 [20.07-21.96]), and sesamoid rotation angle (SRA) (26.72 [24.09-29.34] to 4.56 [1.63-7.50]). The MRA had a low influence in head roundness classification (R²: 0.15). Changes in the pronation classification were explained chiefly by the sesamoid station (SS) (R²: 0.37), where stations 4 to 7 were found to be strong predictors of roundness classifications 2 and 3.

CONCLUSION

Indirect signs of metatarsal pronation, determined by the head round sign, correlate weakly with the alpha angle measured in WBCT. The presence of arthritis and sesamoids displacement might modify the perception of first head roundness. The influence of MRA in the classification was low, where SS from 4 to 7 was strong predictors of a higher pronation classification.

Normative Distribution of First Metatarsal Axial Rotation

BACKGROUND

First metatarsal (M1) axial rotation is recognized as a clinically relevant component of hallux valgus deformity. Methods to realign the M1 in 3 dimensions have been developed. One goal of these operations is to restore normal rotation of the first ray. The aim of this study is to provide estimates for the normal distribution of M1 rotation in patients without relevant anatomic pathology.

METHODS

Using stringent clinical and radiographic criteria, we evaluated a set of plain radiograph and weightbearing computed tomography (WBCT) images of 62 feet from a consecutive patient database. Subjects included had normal foot alignment without bunion symptoms. M1 rotation of each foot was measured using 2 unique methods (Saltzman et al and Kim et al methods). Measurement of rotation was performed by 2 observers from coronal WBCT images. Mean values and confidence intervals (CIs) of M1 rotation were calculated for each method. Inter- and intraobserver reliability values were also reported.

RESULTS

Mean M1 rotation values of 2.1 degrees (95% CI: 0.9-3.4) and 6.1 degrees (95% CI: 4.4-7.8) were identified using the Saltzman et al and Kim et al methods, respectively. Inter- and intraobserver reliability values were interpreted as excellent for both methods.

CONCLUSION

In this study, we describe the natural distribution of the M1 axial rotation in subjects without bunion or other identifiable bony foot deformities. This information should provide a normative reference for surgeons correcting rotational issues of the first metatarsal.

LEVEL OF EVIDENCE

Level III, retrospective cohort 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.