OBJECTIVETo study sagittal mobility about the FTJ (first tarsometatarsal joint) and its relationship with the pathophysiology and treatment of hallux valgus patients.

METHODSAccording to Lee's method, FTJ sagittal mobility of 300 normal feet and 200 hallux valgus was measured, and its correlative factors were statistically analysed.

RESULTSFTJ sagittal mobility of 300 normal feet was 8.4 degrees +/- 2.3 degrees , and that of 200 hallux valgus was 11.7 degrees +/- 3.2 degrees , the difference was significant. The normal range of FTJ sagittal mobility was less than 13 degrees . The sagittal overmotion of FTJ had relation to the anatomical configuration of FTJ (P < 0.05), intercuneiform splitting (P < 0.01), transferred pain under the second metatarsal head (P < 0.01), and FTJ osteoarthritis (P < 0.01) had no relation to HVA (hallux valgus angle), IMA (intermetatarsal angle), second metatarsus medial diaphyseal cortex hypertrophy (P > 0.05).

CONCLUSIONLee's method is convenient and accurate. Both HVA and IMA can not represent the sagittal mobility measurement of FTJ, which should be routinely evaluated, especially for hallux valgus patients with type I FTJ. Lapidus procedure should be considered for patients with larger FTJ in combination with transferred pain under the second metatarsal head, intercuneiform splitting, FTJ osteoarthritis.