Is there a role for non-compression screws (NCS) in surgery?

Role of Non-Compression Screws in Surgery

Non-compression screws play several important roles in surgical applications, particularly in cases where interfragmentary compression is not desired or could be harmful to patient outcomes.

Primary Applications of Non-Compression Screws

1. Bone Metastasis Management

• Non-compression screws are valuable in the treatment of metastatic bone lesions, particularly when combined with other stabilization techniques:
  • For extensive osteolytic destruction or lesions in bones subjected to forces other than compression, non-compression screws are commonly used with cementoplasty 1
  • This combination is particularly effective for extensive iliac lesions or peripheral weight-bearing bones (femur, humerus, and tibia) 1
  • Especially beneficial for patients with limited life expectancy who are unfit for more extensive surgery

2. Anatomically Challenging Areas

• Non-compression screws are preferred in anatomically challenging locations:
  • Particularly useful in areas such as the pelvis or C2 vertebra 1
  • Allow for stabilization in areas where traditional compression techniques might be difficult to apply or potentially harmful

3. Percutaneous Osteosynthesis

• Non-compression screws are essential components in minimally invasive procedures:
  • Used in percutaneous osteosynthesis when combined with cementoplasty for bone stabilization 1
  • Provides favorable outcomes for femoral neck lesions without the morbidity associated with open procedures 1

Limitations of Compression Screws

1. Pathologic Fractures

• Compression screws have limitations in pathologic fractures:
  • Devices like sliding hip screws commonly used for intertrochanteric osteoporotic fractures are not effective in patients with pathologic fractures 1
  • This is primarily due to the lack of bone healing, especially when subsequent bone radiation is planned 1

2. Specific Fracture Types

• For periarticular fractures in patients with metastatic disease, prosthetic replacement often provides more predictable pain relief and return to ambulatory status than compression fixation 1

Technical Considerations

1. Biomechanical Findings

• Recent research challenges traditional assumptions about non-compression screws:
  • Fully threaded screws (traditionally considered non-compression screws) can actually generate interfragmentary compression without requiring special drilling techniques 2
  • This compression occurs through local bone deformation during insertion

2. Clinical Applications

• When using non-compression screws:
  • They can be particularly useful in comminuted fractures where compression might displace fragments
  • In areas with neurovascular structures, non-compression screws minimize the risk of iatrogenic compression of these structures

Pitfalls and Caveats

1. Screw Selection: Choose the appropriate screw type based on fracture pattern, bone quality, and anatomical location rather than defaulting to one type.

2. Reinsertion Issues: Be aware that removing and reinserting screws results in significant loss of compression force, which may affect stability 3.

3. Bone Quality Considerations: Non-compression screws may be preferable in poor quality bone where compression screws might cause further damage.

4. Monitoring: Regular radiographic follow-up is essential when using non-compression screws to ensure maintenance of reduction and proper healing.

Non-compression screws remain an important tool in the orthopedic surgeon's armamentarium, particularly for specific clinical scenarios where compression is contraindicated or where anatomical constraints make compression fixation challenging.