Background In advanced cases of rheumatoid arthritis (RA), Swanson implant have been widely used for hallux valgus deformity. Although the results of this surgery were acceptable, relatively high incidence of recurrence of hallux valgus deformity were reported. In this study, we analyzed the incidence of the recurrence of hallux valgus deformity after Swanson implant surgery, then analyzed for the factors which affect the recurrence of the hallux valgus.
Objectives Post-operative radiological results of implant surgery for hallux in RA with the minimum follow-up of 12 months after surgery were analyzed in 54 cases, 87 joints (3 male cases, 51 female cases). The mean age at the time of surgery was 67.7±6.9 years (53–84). The mean duration after surgery was 40.8±21.6 months (12–93).
Methods Post-operative hallux valgus angle (HVA) was analyzed at pre-, immediate after surgery, 6 months after surgery, and final follow-up. The change of HVA between immediate after surgery and the final follow-up was calculated. The radiological results were evaluated using modified Granberry's grading. The toe lengths of hallux including soft tissue shadow after surgery were divided into three groups using the radiographical of each toe as follows; Type 1 (hallux length is 3 mm longer than 2nd toe length), Type 3 (hallux length is 3 mm shorter than 2nd toe length), and Type 2 (hallux length is within 3 mm of 2nd toe length).
Results The averaged HVA was significantly decreased after surgery, and maintained during follow-up period. There were no statistical correlation between the changes of HVA and follow-up period, pre-operative HVA, and HVA at immediate after surgery. For the toe lengths of hallux, 24 cases were Type 1, 20 cases were Type 2, and 11 cases were Type 3. Type 3 showed significantly less changes of HVA when compared to Type 1. Also, with the shortening of the length of hallux by toe lengths type, the HVA at the final follow-up was significantly decreased. There were no relationship between HVA and Granberry's grading.
Conclusions Improvement of disease activity of RA, total number of RA surgery, especially for large joints has been decreasing. In contrast, the numbers of surgeries for small joints such as finger and toe arthroplasty are increasing. Based on this recent trend of changes of surgery, better clinical and radiological results for small joints will be needed to improve patients' quality of life. Our result clearly showed that the shorter the lengths of hallux, significantly less changes of HVA and HVA at the final follow-up, that may reflect better surgical results of hallux valgus deformity.
Disclosure of Interest Y. Mochida Grant/research support: Bristol-Myers Squibb, Takeda Pharmaceutical Company Limited, Daiichi Sankyo Company, Limited, Mitsubishi Tanabe Pharma Corporation, Teijin Limited, Chugai Pharmaceutical Co., Ltd, Astellas Pharma Inc., K. Ishii: None declared, Y. Yamada: None declared, N. Mitsugi: None declared, T. Saito: None declared