Anterior Cruciate Ligament Graft Failure: An Update on Failure Analysis, Risk Factors, and Surgical Strategies

Revision reconstruction of the anterior cruciate ligament (ACL) presents a considerable challenge - due to its technical complexity, variable clinical presentations, and the interplay of multiple risk factors and concomitant pathologies. Optimal treatment requires a thorough analysis of the causes of failure. The preoperative evaluation should include full-leg radiographs, lateral X-rays of the entire lower leg, magnetic resonance imaging (MRI) to assess soft tissue pathologies, and computed tomography (CT) to evaluate tunnel position and tunnel widening. Graft failure is usually multifactorial and may be related to technical, biological, demographic, or biomechanical causes. Technical issues include malpositioning of the tunnels, unaddressed primary instabilities, fixation failure, or inadequate graft tensioning. Biological factors comprise impaired graft incorporation and infections. Biomechanical and anatomical factors-such as increased posterior tibial slope (PTS), coronal plane malalignment, or persistent peripheral or rotational instabilities-must also be recognised and addressed. For this purpose, additional surgical techniques are available - such as slope-reducing osteotomy, varus and valgus osteotomies, as well as lateral extra-articular tenodesis. A successful revision ACL reconstruction is based on a comprehensive analysis of the underlying causes, individually tailored surgical strategies, correction of modifiable predisposing factors, and realistic patient counseling. These measures are crucial for achieving good functional outcomes and long-term stability, while enabling a safe return to the desired level of activity without recurrent injury.