Hallux valgus: demographics, etiology, and radiographic assessment.

BACKGROUND: The purpose of the study was to preoperatively evaluate the demographics, etiology, and radiographic findings associated with moderate and severe hallux valgus deformities in adult patients (over 20 years of age) treated operatively over a 33-month period in a single surgeon's practice.
METHODS: Patients treated for a hallux valgus deformity between September, 1999, and May, 2002, were identified. Patients who had mild deformities (hallux valgus angle < 20 degrees), concurrent degenerative arthritis of the first metatarsophalangeal joint, inflammatory arthritis, recurrent deformities, or congruent deformities were excluded. When enrolled, all patients filled out a standardized questionnaire and had a routine examination that included standard radiographs, range of motion testing, and first ray mobility measurement. A chart review and evaluation of preoperative radiographs were completed on all eligible patients.
RESULTS: One-hundred and three of 108 (96%) patients (122 feet) with a diagnosis of moderate or severe hallux valgus (hallux valgus angle of 20 degrees or more)(70) qualified for the study. The onset of the hallux valgus deformity peaked during the third decade although the distribution of occurrence was almost equal from the second through fifth decades. Twenty-eight of 122 feet (23%) developed a deformity at an age of 20 years or younger. Eighty-six (83%) of patients had a positive family history for hallux valgus deformities and 87 (84%) patients had bilateral bunions. 15% of patients in the present series had moderate or severe pes planus based on a positive Harris mat study. Only 11% (14 feet) had evidence of an Achilles or gastrocnemius tendon contracture. Radiographic analysis found that 86 of 122 feet (71%) had an oval or curved metatarsophalangeal joint. Thirty-nine feet (32%) had moderate or severe metatarsus adductus. A long first metatarsal was common in patients with hallux valgus (110 of 122 feet; 71%); the mean increased length of the first metatarsal when compared to the second was 2.4 mm. While uncommon, the incidence of an os intermetatarsum was 7% and a proximal first metatarsal facet was 7%. The mean preoperative first ray mobility as measured with Klaue's device was 7.2 mm. 16 of 22 (13%) feet were observed to have increased first ray mobility before surgery.
CONCLUSIONS: The magnitude of the hallux valgus deformity was not associated with Achilles or gastrocnemius tendon tightness, increased first ray mobility, bilaterality or pes planus. Neither the magnitude of the preoperative angular deformity nor increasing age had any association with the magnitude of the first metatarsophalangeal joint range of motion. Constricting shoes and occupation were implicated by 35 (34%) patients as a cause of the bunions. A familial history of bunions, bilateral involvement, female gender, a long first metatarsal, and an oval or curved metatarsophalangeal joint articular surface were common findings. Increased first ray mobility and plantar gapping of the first metatarsocuneiform joint were more common in patients with hallux valgus than in the general population (when compared with historical controls).