Minimally-invasive fixation of distal extra-articular femur fractures with locking plates: limitations and failures.

Minimally-invasive fixation using a locking plate and early motion is normal practice. However, technical errors and pitfalls are common. This surgery has a set of rules that encompass both the mechanics of the internal fixation system and the implantation itself. If these rules are not strictly followed, alignment defects and/or early failure of the fixation can occur. We analysed four cases of clinical failure that were encountered after minimally-invasive distal femoral extra-articular fixation with locking plates. The following rules must be followed with this technique: extra-articular fracture, minimally-invasive approach, long plate alternating between locking screw and empty hole (five holes on either side of fracture), bi-cortical screws, placement of locking screws near a complex fracture but away from a simple fracture. Osteoporotic bone, obesity that interferes with the instrumentation, articular fracture, horizontal fracture line and surgeon experience are all limitations of this minimally-invasive technique.