The Forced Drop Leg Test: A Novel Intraoperative Technique Enhancing Stability Assessments in Total Hip Arthroplasty

Prosthetic instability remains a major challenge in total hip replacement (THR), which can result in dislocation, reduced mobility, and prosthetic loosening, requiring revision surgery. The forced drop leg test (FDLT) introduces a proactive approach by assessing hip stability under forced flexion, adduction, and rotation mimicking real-world dislocation mechanisms.

Standard exposure and trial implants are utilized to evaluate fit and alignment. With the trial components in place, the leg is abducted to 30-40°, then forcefully dropped into a sterile pouch in front. The hip joint is subsequently examined for dislocation or subluxation. In case of any dislocation or subluxation, reassessment of the component size and position is necessary.

Preliminary evidence suggests that FDLT enhances existing stability checks, although broader clinical validation and protocol standardization are necessary to confirm its effectiveness.