Osteoarthritis of the second metatarsophalangeal joint associated with hallux valgus deformity.

Abstract

BACKGROUND: Hallux valgus is speculated to increase the load on the second

metatarsophalangeal (MTP) joint, possibly inducing degenerative osteoarthritis.

In addition, the severity of arthritis may be correlated with the severity of

hallux valgus. This study evaluated the association of arthritis of the second

MTP joint in hallux valgus patients and the relationship between arthritis of the

second MTP joint and hallux valgus deformity. METHODS: A total of 382 patients

(509 feet) underwent surgery for symptomatic hallux valgus deformities by the 2

senior authors (KTL, YUP) from November 2011 to December 2012. A total of 54

patients (61 feet), all female, were included in the osteoarthritis (OA) group.

The rest were assigned to the nonosteoarthritis (NOA) group. There were 328

patients (448 feet) consisting of 16 men and 432 women. Osteoarthritis patients

were then evaluated and classified according to joint space narrowing (JSN) and

osteophyte (OP) formation. A statistical analysis was conducted to compare the 2

groups in terms of their hallux valgus angle (HVA), intermetatarsal angle (IMA),

distal metatarsal articular angle (DMAA), hypermobility of the first metatarsal

ray, the length of the second metatarsal bone, and the length ratio of the first

and second metatarsal bones. Correlation coefficients were calculated to compare

the severity of hallux valgus and the degree of osteoarthritis of the second MTP

joint. RESULTS: The IMA of the OA group was 16.2 +/- 2.9 degrees, and that of the

NOA group was 15.4 +/- 3.3 degrees (P = .034, Mann-Whitney U test). The DMAA of

the OA group was 18.2 +/- 8.3 degrees, and that of the NOA group was 16.1 +/- 8.0

degrees (P = .029, Mann-Whitney U test). There were no significant differences

between the 2 groups in terms of the HVA, hypermobility, the length of the second

metatarsal bone, and the length ratio of the second and first metatarsal bones.

In the OA group, there was a positive correlation between the HVA and the degree

of osteoarthritis (osteophyte formation) ( = 0.278, P = .030). In addition, there

was a positive correlation between the IMA and the degree of osteoarthritis ( =

0.284 [JSN], 0.327 [OP] for the HVA, P = .026 [JSN], .010 [OP]). However, there

was no significant difference between hypermobility and the degree of

osteoarthritis (P = .356 [JSN], .635 [OP], Mann-Whitney U test). Furthermore,

there were no positive correlations between the DMAA, the length of the second

metatarsal bone, and the metatarsal length ratio. CONCLUSION: Our study

demonstrated a positive correlation between HVA, IMA, and osteoarthritis of the

second MTP joint. Other studies will be needed to determine the factors that are

responsible for this correlation. LEVEL OF EVIDENCE: Level III, retrospective

comparative series.