Weightbearing Computed Tomography and 3-Dimensional Analysis of Mobility Changes of the First Ray After Proximal Oblique Osteotomy for Hallux Valgus

Radiographic Assessment of Transverse Tarsometatarsal Instability Complicated by Metatarsus Adductus in Hallux Valgus Patients

Objective evaluations of transverse tarsometatarsal (TMT) hypermobility/instability are lacking. This study aims to radiographically explore the relationship between transverse TMT instability and metatarsus adductus (MA) in hallux valgus (HV). This study retrospectively analyzed 207 feet with varying degrees of HV, employing the distance between the first and second metatarsals (M1-2 distance) to assess transverse TMT instability of the first ray. Participants were categorized into MA and non-MA groups. It was found that the M1-2 distance significantly increased with the hallux valgus angle (HVA) and metatarsus adductus angle (MAA), demonstrating significant differences between the MA and non-MA groups. The measurement of M1-2 distance showed high reliability, and its cutoff value was determined to be 4.05 mm. Additionally, the results suggest that the widening of the M1-2 distance may be a predisposing factor for MA in HV patients, highlighting its role in the pathogenesis of this foot condition. These findings highlight the need for a comprehensive assessment of TMT instability on both the axial and sagittal planes for the surgical planning of HV, particularly when complicated by a large MAA. Based on these insights, reoriented first-TMT arthrodesis might be recommended for HV with significant MA to address potential multiplanar instability.

First ray mobility in hallux rigidus, hallux valgus, and normal feet based on weightbearing computed tomography and three-dimensional analysis: A case-control study

BACKGROUND

Hallux valgus and hallux rigidus are disorders affecting the first ray and are associated with hypermobility of this structure. This study aimed to investigate the three-dimensional mobility of each joint of the first ray between feet with hallux valgus or hallux rigidus and healthy feet using weightbearing and nonweightbearing computed tomography (CT).

METHODS

This case-control study analyzed 17 feet of 11 healthy volunteers (control group), 16 feet of 16 patients with hallux valgus (HV group), and 16 feet of 11 patients with hallux rigidus (HR group). First, nonweightbearing foot CT imaging was performed in the supine position on a loading device with no load applied, with the legs extended and the ankle in the neutral position. Next, a load equivalent to body weight was applied for weightbearing CT imaging. Distal bone displacement relative to the proximal bone was quantified three-dimensionally under both conditions.

RESULTS

In the HV group, the talonavicular joint showed significantly greater eversion (P = 00.011) compared with the control group and significantly greater dorsiflexion (P = 00.027) and eversion (P < 00.01) compared with the HR group. In the medial cuneiform joint, the HV group showed significantly greater eversion (P < 00.01) and abduction (P = 00.011) than the control group. For the first tarsometatarsal joint, the HV group showed significantly greater dorsiflexion (P = 00.014), inversion (P = 00.028), and adduction (P < 00.01) than the control group, and greater inversion (P < 00.01) and adduction (P < 00.01) than the HR group. Dorsiflexion of the first tarsometatarsal joint was significantly greater in the HR group compared with the control group (P = 00.026).

CONCLUSION

Hypermobility of the first ray appears to be three-dimensional: in hallux valgus, it is centered at the first tarsometatarsal joint, while in hallux rigidus it is mainly in the sagittal plane at the first tarsometatarsal joint only. This difference may explain the different deformities ultimately observed in each condition.

Radiological Analysis of the Syndesmosis Concept in Metatarsus Primus Varus and Hallux Valgus Deformities Recurrence Prevention

Hallux valgus (HV) is a common deformity of the foot. Its postoperative recurrence is not uncommon and is closely related to the recurrence of its underlying metatarsus primus varus (MPV) deformity. The syndesmosis procedure uses 1 to 2 intermetatarsal cerclage sutures to realign the first metatarsal and then induces a biological bonding between the 2 metatarsals to prevent the MPV deformity from recurring. This radiological study aimed to assess its effectiveness in long-term MPV and HV deformities recurrence prevention. Ninety-two feet of 51 consecutive patients had syndesmosis procedures that were prospectively followed up for more than 1 y and up to 14 y, averaging 100.5 (SD 45.2) months. Patients underwent X-ray examinations regularly at fixed intervals of their feet. We used Hardy's methods in measuring the intermetatarsal angle (IMA), hallux valgus angle (HVA), and medial sesamoid position from standing foot X-rays. More than 450 relevant X-ray and photo images were submitted as Supplementary Material for online viewing and reference. There was a significant final correction of IMA from 14.30° (SD 2.70) to 6.70° (SD 1.75) (p < .0001). There was no significant increase in IMA after the sixth postoperative month to their final follow-up endpoints, regardless of their lengths. There was a significant final correction of HVA from 31.95° (SD 7.45) to 19.1° (SD 7.45) (p < .0001). This study reconfirmed past findings that the MPV deformity could be corrected without osteotomies. Creating a syndesmosis-like intermetatarsal bonding was effective for long-term MPV recurrence prevention. Three feet had postoperative stress fracture of the second metatarsal. However, the HV deformity correction was less satisfactory, and the reasons were explained.

Relationship between arthritis of the second and third tarsometatarsal joints and incongruity of the first tarsometatarsal joint in patients with hallux valgus

OBJECTIVES

Hallux valgus is associated with tarsometatarsal arthritis; its pathophysiology remains unknown. Therefore, we aimed to elucidate the relationship between arthritis of the second and third tarsometatarsal joints and incongruity of the first tarsometatarsal joint in the sagittal plane.

METHODS

Forty-three patients (64 feet) with hallux valgus who underwent surgery at University Hospital Kyoto Prefectural University of Medicine were included and divided into two groups: control (without second and third tarsometatarsal joint degeneration) and osteoarthritis (with second and third tarsometatarsal joint degeneration). Intergroup comparisons of the incongruity of the first tarsometatarsal joint in the sagittal plane, age, body mass index, hallux valgus angle, first-second intermetatarsal angle, metatarsus adductus angle, Meary's angle, and calcaneal pitch angle were performed.

RESULTS

The proportion of patients with incongruity of the first tarsometatarsal joint was significantly higher in the osteoarthritis group than in the control group. Logistic regression analysis identified incongruity of the first tarsometatarsal joint and metatarsus adductus angle as significant related factors for arthritis of the second and third tarsometatarsal joints.

CONCLUSIONS

Incongruity of the first tarsometatarsal joint in the sagittal plane was involved in the development of arthritis of the second and third tarsometatarsal joints in patients with hallux valgus.

Three-Dimensional Analysis of the Windlass Mechanism Using Weightbearing Computed Tomography in Healthy Volunteers

BACKGROUND

The windlass mechanism (WM) increases the longitudinal arch of the foot via tension of the plantar aponeurosis during dorsiflexion of the metatarsophalangeal (MTP) joint. The purpose of this study was to perform a 3-dimensional evaluation of the displacement of each joint and the height of the navicular during dorsiflexion of the first MTP joint by using weightbearing computed tomography (CT).

METHODS

Participants were 6 men and 8 women with 23 healthy feet. CT of the foot with a load equivalent to the participant's body weight was performed. The first MTP joint was in the neutral position and dorsiflexed 30 degrees. Between the conditions, we measured the (1) rotation of each bone, (2) rotation of the distal bone with respect to the proximal bone at each joint, and (3) height of the navicular.

RESULTS

With respect to the tibia, the calcaneus was at 0.8 ± 0.7 degrees dorsiflexion and 1.4 ± 0.9 degrees inversion, while the talus was at 2.0 ± 1.2 degrees dorsiflexion and 0.1 ± 0.8 degrees eversion. The navicular was at 1.3 ± 1.2 degrees dorsiflexion and 3.2 ± 2.1 degrees inversion, whereas the medial cuneiform was at 0.3 ± 0.6 degrees plantarflexion and 1.3 ± 1.1 degrees inversion. At the talonavicular joint, the navicular was at 0.7 ± 1.3 degrees plantarflexion, whereas at the cuneonavicular joint, the medial cuneiform bone was at 1.4 ± 1.4 degrees plantarflexion. The height of the navicular increased by 1.1 ± 0.6 mm.

CONCLUSION

We 3-dimensionally confirmed the dynamics of WM and found that the calcaneus, navicular, and medial cuneiform moved in all 3 planes. The results suggest that the cuneonavicular joint has the greatest movement among the joints. We believe that these findings will help to elucidate the pathogenesis of WM-related diseases and lead to advances in treatments for pathologies involving the longitudinal arch.

LEVEL OF EVIDENCE

Level IV, case series.

The Assessment of Ankle Osteoarthritis with Weight-Bearing Computed Tomography

The standard for diagnostic radiographic imaging in foot and ankle surgery was until 2012 radiographs with full weight-bearing without any useful alternative. Weight-bearing cone-beam computed tomography (WBCT) was introduced 2012 for foot and ankle use as a new technology that allows 3D imaging with full weight-bearing which should be not influenced by projection and/or foot orientation. The assessment of ankle osteoarthritis with WBCT including the description of healthy status, effect of alignment and7or (in)stability is extensively illustrated in this review article.

Multiplanar instability of the first tarsometatarsal joint in hallux valgus and hallux rigidus patients: a case-control study

BACKGROUND

Hypermobility of the first ray has been considered associated with various forefoot diseases including hallux valgus (HV) and hallux rigidus (HR). Weightbearing CT scan can be a reliable method for analysis of the first tarsometatarsal (TMT) joint in axial, sagittal, and coronal planes. Our objective was to comparatively investigate signs of instability of the first TMT joint on weightbearing CT between three groups (control, HV, and HR).

METHODS

In this single-centre, retrospective, case-control study, 27 HV patients (30 feet; mean age 54.2 years), 26 HR patients (30 feet; mean age 56.6 years), and 30 controls (30 feet; mean age; 43 years) were enrolled. Measurements of signs of instability were performed in multiplanes including first TMT angle, dorsal translation of the first metatarsal (M1) at the first TMT joint, plantar distance between the medial cuneiform (C1) and M1 in sagittal plane, hallux valgus angle (HVA), intermetatarsal angle (IMA) in axial plane, rotational profiles of C1 and M1 in coronal plane. Analysis of variance (ANOVA) test and chi-square test were performed to compare each parameter between the three groups. Interobserver reliabilities were assessed using interclass correlation coefficients (ICCs).

RESULTS

The HV group had significantly increased first TMT angle (0.23° in controls, 1.15° in HV, 0.19° in HR, p < 0.001), HVA (7.52°, 33.50°, 11.21°, p < 0.001), IMA (9.46°, 16.98°, 11.87°, p < 0.001), C1-M1 angle (22.44°, 29.46°, 23.74°, p < 0.001), and rotational profile of the distal M1 (7.06°, 17.88°, 9.85°, p < 0.001) compared with the control and HR groups. Dorsal translation of M1 (23% in controls, 63% in HV, 70% in HR, p < 0.001) was frequently found in the HV and HR groups with significantly increased plantar distance (0.37 mm, 1.14 mm, 1.46 mm, p < 0.001) compared with controls.

CONCLUSIONS

Multiplanar instability of the first TMT joint was confirmed using weightbearing CT in HV and HR groups compared with controls. HV group demonstrated instability mainly in sagittal and axial planes; HR group had sagittal instability predominantly. Our measurement of rotational instability at the first TMT joint was not able to detect differences between groups. A surgical correction of the instability at the first TMT joint can be an option to address HV and HR.

CLINICAL RELEVANCE

First ray hypermobility at the first TMT joint is an important consideration when addressing HV and HR, a surgical correction of the instability at the first TMT joint should be taken in consideration as an option.