[Patellar fractures : Overview of surgical treatment concepts]

The goal is to anatomically reconstruct the patellar joint surface in order to restore the function of the extensor apparatus. This forms the basis for a stable knee function and physiological gait. Furthermore, it prevents retropatellar arthritis. Early functional mobilization can prevent joint stiffness, muscle atrophy and subsequent complications.

Open or closed patellar fractures with > 2 mm joint incongruity or displacement, impaired extensor mechanism or absent active extension, even if not displaced.

Stable, nondisplaced fractures, minimal displacement with an intact extensor mechanism, limited surgical eligibility, here conservative therapy is preferred.

The choice of procedure depends on the fracture type: for simple vertical fractures, screw osteosynthesis; for transverse fractures (1) tension band wiring with Kirschner wires or (2) cannulated screws, alternatively (3) conventional angle stable plate fixation (preferred); for complex, multifragmentary fractures, locking plate fixation. Additional procedures, such as suture augmentation or cerclage wiring can be used as needed.

Full weight-bearing in an extension splint is permitted, with gradual passive mobilization: up to 30° in weeks 1-2, 60° in weeks 3-4, and 90° in weeks 5-6. Subsequent transition to unlimited flexion and active mobilization. Sport-specific training is possible after 3-6 months.

Tension band wiring has traditionally been used for patellar fractures but shows high complication rates, especially in complex, multifragmentary fractures. Recent studies show that locking plate osteosynthesis is more stable and has fewer complications.