Early radiologic outcome and technical details of MIS
bunionectomy using a guided trajectory system is reported here.
From April 2022 to March 2023, 20 consecutive minimally invasive
bunionectomies were performed on 17 female patients (bilateral in 3
patients) with an average age of 63.6 (range: 46 to 82). The mean
IMA improved from 14.3 degrees (SD: 3.2) to 4.6 degrees (SD: 2.0),
HVA from 28.2 degrees (SD: 6.3) to 6.7 degrees (SD: 2.8), DMAA
from 16.6 degrees (SD: 5.6) to 6.6 degrees (SD: 1.8). Preoperatively,
17 feet (89.5%) were in TSP grades 2 and 3. Postoperatively, 19 feet
(95%) improved to either TSP grades 0 and 1. The mean duration of
operative time was 50 (SD: 9.25, range: 23 to 65) minutes. No
intraoperative complications were reported. Overall, this study
provides valuable insights into the benefits of using a guided trajectory
system to improve the success of bunion correction surgeries.
Level of evidence: Level 4.

Background: Recent literature highlights the importance of treating hallux valgus (HV) as a 3-dimensional (3D) deformity.
Although 3D printing may enhance visualization of the multiplanar aspects of HV, its influence on surgical planning remains unclear. This study assessed changes in surgical plans when surgeons sequentially reviewed 2D radiographs, 3D weightbearing computed tomography (WBCT), and 3D-printed models, hypothesizing that 3D printing would have the greatest impact.

Methods: A single HV case (a 40-year-old woman, intermetatarsal angle [IMA] 21 degrees, HV angle [HVA] 47 degrees) was evaluated by 30 surgeons in a masked, stepwise manner. Surgical plans were recorded at each stage. Surgeons rated the influence of WBCT and 3D printing using a 5-point Likert scale. A follow-up survey examined the effect of these technologies on correction amplitudes.

Results: The participants were mostly early career surgeons (median age 35.5 years, 2 years in practice). WBCT was accessible to 43.3% and used in 30% of HV cases, whereas 3D printing was accessible to 23.3% and used in 6.6%. Changes in the treatment algorithm occurred in 30% of cases after WBCT and in 43.3% after 3D printing. Significant differences (P < .05) were observed for the Lapicotton procedure between radiography and WBCT, and between WBCT and 3D printing. Surgeons performing <50 HV cases annually or with >70% Foot and Ankle specialization were more influenced by WBCT. Follow-up data (n = 23) indicated that WBCT and 3D printing influenced correction amplitudes, particularly for pronation and distal metatarsal articular angle (DMAA), more than for the IMA.

Discussion: Both WBCT and 3D printing influenced surgical planning, mostly explained by changes in first ray tarsometatarsal procedures. The rotational components (pronation and DMAA) were perceived as the most significantly affected. Future studies should explore cost-effectiveness, patient outcomes, and the utility of combining WBCT and 3D
printing in other deformities requiring multiplanar corrections.

Level of Evidence: Level IV, cross-sectional survey.

Background: Proximal fifth metatarsal fractures are common injuries that are classified into 3 zones according to their anatomical localization. While zone 1 and 2 fractures typically are traumatic, zone 3 fractures may be linked to foot alignment abnormalities, such as hindfoot varus and metatarsus adductus. The aim of the study was to explore the association between hindfoot alignment and different fracture zones, as well as the relationship between traumatic and atraumatic fracture origin and foot alignment.

Methods: We conducted a retrospective cohort study of patients with proximal fifth metatarsal fractures who had received a weightbearing computed tomography (WBCT) scan. Feet with zone 1 and 2 fractures were compared to zone 3
fractures and a healthy control group. Additionally, we compared feet with a traumatic fracture origin with those without.
Foot alignment parameters, including the foot and ankle offset (FAO) and the forefoot arch angle (FAA), were analyzed alongside data from semiautomated segmentation reports. P <.05 was considered significant.

Results: The study included 45 fractures (23 zone 1 and 2, 22 zone 3) and 19 controls. Zone 3 fractures showed a significant association with higher body mass index (P < .01), hindfoot varus (P < .01), and metatarsus adductus (P < .01) compared with zone 1 and 2 fractures, and they more frequently had a nontraumatic origin (P < .01). Zone 3 fractures also showed a significantly higher transverse arch (P < .01). No differences have been observed between zone 1 and 2 fractures and the controls. Fractures with atraumatic origin were significantly associated with hindfoot varus (P < .01), metatarsus adductus (P < .01), hindfoot varus (P < .01), and metatarsus adductus (P < .01).

Conclusion: Hindfoot varus, metatarsus adductus, and a high transverse arch were significantly associated with zone 3 fractures as well as fractures with atraumatic origin.

Background: Hallux valgus (HV) is a complex, multiplanar deformity. In this study, we examined the interrelationships
between various components of this deformity using weightbearing computed tomography (WBCT). We hypothesized
that the severity of traditional axial plane deformities would correlate with malpositioning of the metatarsosesamoid
complex, first-ray coronal rotational deformity, and malalignment of the hindfoot and midfoot. The findings may offer
valuable insights for guiding the correction of HV deformities.

Methods: Patients with an HV angle greater than 15 degrees who underwent WBCT were included. Traditional
2-dimensional parameters were semiautomatically assessed. Manual measurements included hindfoot and midfoot WBCT
parameters, for example, foot and ankle offset, talar posterior and middle facet morphology, and forefoot arch angle.
First-ray parameters, including first metatarsal rotation, sesamoid rotation angle, hallucal pronation angle, and sesamoid
position, were measured using established methods. Patients were categorized by hindfoot moment arm values to evaluate
hindfoot-forefoot relationships.

Results: Sixty-eight feet (53 patients) were included. Manual measurements exhibited excellent interobserver reliability,
with ICCs of 0.845 to 0.987 and a kappa coefficient of 0.899 for the sesamoid position. The mean HV angle was 27.4 ± 7.8
degrees, whereas the mean IM angle was 15.8 ± 3.5 degrees. Significant correlations were observed between the HV
and intermetatarsal (IM) angles, with all metatarsosesamoid complex parameters and first-ray coronal plane rotational
parameters distal to the metatarsal head. The axial and sagittal talar–first metatarsal angles correlated with the HV angle
but not with the IM angle. Significant differences in the HV angle, sagittal first tarsal–metatarsal joint angle, and first
metatarsal head rotation were observed between the hindfoot moment arm groups, as confirmed by post hoc analysis.

Conclusion: The findings support our hypothesis, identifying significant correlations between metatarsosesamoid complex
malposition, distal first-ray coronal pronation, and traditional axial plane deformities in HV. Some hindfoot–midfoot
alignments correlated with the HV angle but not with the IM angle.

Level of Evidence: Level IV: case series.

Background: Progressive collapsing foot deformity (PCFD) and hallux valgus (HV) are complex 3-dimensional deformities
of the foot. This study aimed to investigate structural and alignment differences between PCFD with and without HV using
weightbearing computed tomography.

Methods: Patients with PCFD aged 18 years or older who underwent weightbearing computed tomography were
consecutively enrolled. Standard 2-dimensional PCFD and HV parameters were assessed semiautomatically. Foot and ankle
offset, forefoot arch angle, and pronation of the medial column bones in the coronal plane, with the ground as a reference,
were manually measured. Additionally, the angles from the inferior aspect of subtalar posterior facet of the talus to the
ground (subtalar horizontal angle), from the inferior (posterior facet) to superior facets of the talus (infratalar-supratalar
angle), and from the inferior (posterior facet) of the talus to the superior facet of the calcaneus (infratalar-supracalcaneal
angle) were examined. HV deformity was defined by an HV angle of ≥15 degrees.

Results: Among 72 feet (58 patients) studied, 33 displayed HV, whereas 39 did not. In the coronal plane, the PCFD
with HV group showed a higher infratalar-supratalar angle and greater pronation at the first tarsometatarsal joint, first
metatarsal bone, and head. The PCFD with HV group also exhibited greater naviculocuneiform joint supination. Generalized
estimating equation logistic regression analysis revealed significant associations of HV deformity with the intrinsic rotation
of the first metatarsal bone (P < .001), infratalar-supratalar angle (P = .004), and rotation of the first tarsometatarsal joint
(P < .001).

Conclusion: This study confirmed significant structural and alignment differences between PCFD with and without
HV. Notably, the infratalar-supratalar angle, rotation of the first tarsometatarsal joint, and intrinsic rotation of the first
metatarsal bone were associated with HV deformity.

Level of Evidence: Level III, retrospective comparative study.

Background: The main goal of this study was to evaluate postoperative changes in the length of the first metatarsal
(M1) and the proximal phalanx of the hallux (P1) after acellular dermal allograft interpositional arthroplasty (ADAIPA).
We hypothesized that there would be a shortening of the first ray at the first metatarsal, the proximal phalanx,
or both.

Methods: In this retrospective study, we assessed patients who underwent ADA-IPA between 2019 and 2022. On
standing anteroposterior (AP) foot radiographs, we measured first metatarsal (M1), second metatarsal (M2), proximal
phalanx (P1), and the entire hallux (HX) lengths. M1/M2 and P1/HX ratios were calculated. The first metatarsophalangeal
joint space was calculated. All measurements were recorded preoperatively, at 6 weeks postoperatively, and at final
follow-up.

Results: The pilot study included 11 patients. At final follow-up, we found shortening of M1 and P1 in comparison to
the preoperative length, as evidenced by lower M1/M2 (82.6 ± 2.3 vs 75.4 ± 5.1; P = .001) and P1/HX ratios (53.4 ± 2.3 vs
48.9 ± 7.9; P = .001). Follow-up length was negatively correlated with M1/M2 (r = −0.76, P = .003).

Conclusion: ADA-IPA might be associated with shortening of both first metatarsal and proximal phalanx, with the former
showing progressive shortening.

Level of Evidence: Level IV, retrospective case series.