What makes a patellar fracture considered operative?

Indications for Operative Management of Patellar Fractures

Surgical treatment is recommended for patellar fractures with articular step-off > 2 mm, fracture displacement > 3 mm, disruption of the extensor mechanism, or open fractures. 1

Primary Indications for Surgery

• Disruption of the knee extensor mechanism, which is required for unassisted gait 2
• Articular step-off greater than 2 mm 1
• Fracture displacement greater than 3 mm 1
• Open fractures 1

Evaluation Process

• Standard radiographs (anteroposterior and lateral views) should be used initially to assess fracture pattern, displacement, and articular congruity 3
• CT may be necessary when radiographs are inconclusive, especially to detect occult fractures using metal artifact reduction techniques 3
• Weight-bearing axial radiographs help evaluate patellofemoral kinematics and demonstrate the degree of patellar tilt or subluxation 4

Fracture Patterns Requiring Surgery

• Transverse fractures, which are often associated with patellar maltracking 5
• Vertical fractures that occur through fixation holes in post-arthroplasty patients 5
• Comminuted fractures with articular incongruity, as failure to restore the articular surface results in posttraumatic arthritis 6
• Multiple fracture lines (flail segments) where both fracture lines should be stabilized whenever possible 5

Anatomical Considerations

• SSRF (Surgical Stabilization of Rib Fractures) principles can be applied to patellar fractures, where all displaced fragments should be stabilized whenever possible 5
• Fractures in specific locations may require specialized fixation techniques:
  • Fractures near cartilage may need spanning plates 5
  • Fractures abutting bony processes may be repaired if reliable fixation can be obtained on the proximal fragment 5

Surgical Techniques

• Tension band wiring is the most commonly employed surgical technique 6
• For comminuted fractures, supplementation or replacement of tension band wire with:
  • Interfragmentary screws
  • Cerclage wire or suture
  • Plate-and-screw constructs 2

Potential Complications of Surgical Management

• Nonunion
• Infection
• Posttraumatic arthritis
• Arthrofibrosis
• Symptomatic hardware
• Extensor mechanism insufficiency 7

Rehabilitation Considerations

• Comprehensive rehabilitation program is essential following surgical fixation, including:
  • Range of motion exercises
  • Strengthening exercises
  • Gait training
  • Balance and proprioception training 8

Caveats and Pitfalls

• Hardware often needs to be removed after fracture healing due to implant-related pain 6
• Patellofemoral arthritis is very common after healing of patellar fractures 2
• Substantial functional deficits may persist long after fracture healing 2
• Pre-operative CT may change both classification and treatment by providing better understanding of fracture complexity 6
• Meticulous handling of soft tissues is crucial given the patella's tenuous blood supply and limited soft-tissue envelope 1