Radiographic Subluxation Following Total Hip Arthroplasty in Flexed-Seated Position: A Report of 3 Cases

Abstract

Case: We present 3 cases demonstrating radiographic posterior subluxation in lateral functional radiographs taken in the flexed-seated position. Two of the patients were asymptomatic, and 2 showed the posterior translation of the femoral head, which is almost a dislocation, with spontaneous reduction. The subluxation can occur not only in patients after lumbar fusion surgery but also in patients with relatively normal lumbar spine due to excessive hip flexion.

Conclusion: Functional lateral radiographic assessment in the flexed-seated position may be useful in detecting asymptomatic subluxation and identifying patients at high risk of dislocation after THA.