Impact of crossover second toe on the postoperative outcome of distal chevron osteotomy for moderate to severe hallux valgus

Ultrasonography-Based Quantitative Evaluation of Second Metatarsophalangeal Joint Instability in Female Patients With Hallux Valgus

BACKGROUND

Patients with moderate to severe hallux valgus (HV) sometimes exhibit second metatarsophalangeal (MTP) joint dislocation. Second MTP joint instability due to plantar plate (PP) injury has been suggested as one of the causes. However, there have been no reports that quantitatively evaluate this instability. This study aimed to evaluate second MTP joint instability in patients with HV without dislocation via ultrasonography and investigate its relationship with the presence of PP injury or foot form.

METHODS

Between May 2018 and July 2023, symptomatic female patients with HV without any lesser toe deformity were included in this study. Second MTP joint instability was defined as the dorsal displacement ratio (DDR) of the passively subluxated proximal phalangeal articular surface on the metatarsal head articular surface. The presence of PP injury was assessed using ultrasonography. Foot "form" was determined by measuring standard foot bony angles on weight-bearing foot-ankle radiographs. The relationship between DDR or PP injury and radiographic measurements was investigated.

RESULTS

Sixty-four patients (100 feet) were included. The average DDR of the second MTP joint in patients with HV without dislocation was 35.7%. There was an increase in the probability of PP injury, above a cutoff DDR value r of 35.4% (area under the curve = 0.712). The sensitivity, specificity, positive predictive value, and negative predictive value for the presence of PP injury based on this cutoff level were 63.9%, 74.4%, 79.6%, and 56.9%, respectively. Metatarsalgia was reported in 21 feet (21.0%), of which 15 feet (71.4%) showed PP injury. An increase in DDR was weakly associated with increased metatarsus adductus angle and decreased second metatarsal height.

CONCLUSION

In female patients with HV without second MTP dislocation, we found ultrasonographic evidence of second MTP plantar plate injury and joint instability to be a relatively common finding with a high prevalence in those with localized metatarsalgia.

LEVEL OF EVIDENCE

Level II, development of diagnostic criteria based on consecutive patients.

Prevalence and radiological characteristics of the dislocation of the second metatarsophalangeal joint in patients undergoing hallux valgus surgery; a matched control study

BACKGROUND

Hallux valgus (HV) is occasionally associated with chronic subluxation or dislocation (CS/D) of the second metatarsophalangeal joint (2MTPj). The present study aimed to radiographically investigate the prevalence and characteristics of HV with CS/D of the 2MTPj compared with matched controls.

METHODS

Dorsoplantar and lateral weight-bearing radiographs of 79 female patients (79 feet) who had HV with an age of 50 years or more were reviewed. All feet were treated with a proximal supination osteotomy for correction of HV. CS/D of the 2MTPj was evaluated on preoperative dorsoplantar and lateral radiographs. HV and intermetatarsal (IM) angles were measured. Seventy-nine feet were divided into two groups: Group CD (16 feet) had HV with CS/D of the 2MTPj, and Group non-CD had HV without the CS/D of the 2MTPj (63 feet). The severity of HV was divided into two grades according to the HV angle: moderate deformity (Group M, 36 feet, HV angle of less than 40°) and severe deformity (Group S, 43 feet, HV angle of 40° or greater). Group CD and non-CD, and Group M and S were matched by age, gender, and BMI.

RESULTS

The prevalence of CS/D of the 2MTPj was 20.3%. Group CD had a significantly higher HV angle (p = 0.0001) and a significantly higher IM angle (p = 0.042) than Group non-CD. The prevalence of CS/D of the 2MTPj in Group S (34.9%) were significantly higher than that in Group M (2.8%) (p < 0.001).

CONCLUSIONS

CS/D of the 2MTPj was significantly associated with greater HV and IM angles compared with matched controls. The prevalence of CS/D of the 2MTPj (34.9%) in Group S was significantly higher than that in Group M. Severe HV can be at higher risk of acquiring CS/D of the 2MTPj in middle-aged and older females.