Imaging Findings and First Metatarsal Rotation in Hallux Valgus

Abstract

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.

Fourth-Generation Minimally Invasive Hallux Valgus Surgery With Metaphyseal Extra-Articular Transverse and Akin Osteotomy (META): 12 Month Clinical and Radiologic Results

“…Recent studies have confirmed that there is considerable rotation of the first metatarsal in hallux valgus deformity, which should be corrected as part of the overall deformity correction. 8,41,49,57,58 A transverse osteotomy potentially allows better rotational control and correction of the head compared to a chevron. As a transverse osteotomy is inherently unstable, it does have to be controlled with a reduction maneuver during fixation; otherwise, there is a risk of malunion in the sagittal plane.…”

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

“…The percutaneous technique also allows rotational correction of the first metatarsal, which is increasingly recognized as an important factor leading to recurrence. 10,36,44 We did not find any evidence of radiographic osteoarthritis of the first TMTJ joint in the long-term follow-up radiographs. It should be noted that with increasing shifts (>~75%), the chevron cut does not impede rotational correction.…”

Relationship Between Hallux Valgus Recurrence and Sesamoid Position on Anteroposterior Standing Radiographs After Distal Chevron Metatarsal Osteotomy

“…Thus, even when IMA correction results in sesamoid reduction, it may not be adequately reflected by sesamoid grade on weightbearing AP radiographs, and conversely apparent reduction on AP standing radiographs may not indicate reduction of the metatarso-sesamoid complex. 16 Twodimensional weightbearing AP radiographs after surgery may be limited in evaluating 3-dimensional deformities. [12][13][14] The accuracy of HVA, IMA, and TSP measurements in this study was enhanced by setting the reference line as the line from the center of the distal head to the proximal end of the diaphysis.…”

“…Thus, even when IMA correction results in sesamoid reduction, it may not be adequately reflected by sesamoid grade on weightbearing AP radiographs, and conversely apparent reduction on AP standing radiographs may not indicate reduction of the metatarso-sesamoid complex. 16 Two-dimensional weightbearing AP radiographs after surgery may be limited in evaluating 3-dimensional deformities. 12-14…”