Does total hip arthroplasty via the direct anterior approach using dual mobility increase leg length discrepancy compared with single mobility?

• Main Authors: Seiya Ishii, Yasuhiro Homma, Tomonori Baba, Yuta Jinnai, Xu Zhuang, Hiroki Tanabe, Sammy Banno, Mikio Matsumoto, Taiji Watari, Yu Ozaki, Hironori Ochi, Kazuo Kaneko
• Format: Article
• Language: English
• Published: BMC 2021-01-01
• Series: Arthroplasty
• Subjects: Leg length discrepancy; Direct anterior approach; Dual mobility cup
• Online Access: https://doi.org/10.1186/s42836-020-00060-6

Abstract Background Total hip arthroplasty (THA) via the direct anterior approach (DAA) using dual mobility cup (DMC) is considered to effectively prevent postoperative dislocation. However, the dislocation and reduction procedure using a trial implant during the surgery is difficult because of high soft tissue tension. Thereby, leg length discrepancy (LLD) is difficult to assess when using DM via the DAA. Purpose To compare the LLD between cases using conventional SM and those using DMC in THA via the DAA with fluoroscopy. Patients and methods We retrospectively investigated 34 hips treated with DMC (DMC-DAA group) and 31 hips treated with SM (SM-DAA group). The LLD was defined as the difference in the distance from the teardrop to the medial-most point of the lesser trochanter between the operative and nonoperative sides at immediate postoperative X-ray. Results The mean LLD in the DMC-DAA group and SM-DAA group was 0.68 ± 7.7 mm and 0.80 ± 5.5, respectively, with no significant difference. The absolute value of the LLD in the DMC-DAA group and SM-DAA group was 6.3 ± 4.4 mm and 5.9 ± 5.5, respectively, with no significant difference. Conclusion Despite the difficulty in assessment of the LLD during THA via the DAA using DMC, this technique does not increase the LLD compared with the use of SM. Level of evidence III, matched case-control study.