Association of Abnormal Metatarsal Parabola With Second Metatarsophalangeal Joint Plantar Plate Pathology.

BACKGROUND

Plantar plate pathology is common, yet it is unclear whether, and to what extent, the length of the second metatarsal contributes to this problem.

METHODS

We conducted a retrospective case-control (1:2) study to examine radiographic risk factors for plantar plate tears. One hundred patients (age 55.7 ± 12.3 years) with plantar plate injuries and 200 healthy controls (age 56.3 ± 11.3 years) were included. Cases were defined as patients with nonacute, isolated, plantar plate pathology of the second metatarsophalangeal joint confirmed by intraoperative inspection at a single foot and ankle specialty practice from June 1, 2007, to January 31, 2014. Patients presenting for pain outside of the forefoot served as the control group. Controls were matched on age (±2 years), gender, and year of presentation. Weight-bearing foot x-rays were assessed for several predetermined angular relationships by a single rater. Conditional logistic regression was used to identify risk factors for plantar plate injury.

RESULTS

A long second metatarsal, defined as a metatarsal protrusion index less than -4 mm, was the only significant risk factor for plantar plate pathology in both the univariate and multivariable analyses (multivariate odds ratio 2.5 [95% confidence interval 1.8 to 3.3], P = .002).

CONCLUSION

We found that a long second metatarsal was a risk factor for developing second metatarsophalangeal joint plantar plate tears. This knowledge may aid foot and ankle surgeons when contemplating the need for second metatarsal shortening osteotomies (eg, Weil osteotomy) during plantar plate surgery and when deciding on the amount of shortening for second metatarsal osteotomies.

LEVEL OF EVIDENCE: Level III, retrospective comparative study.