Screw Placement in Plates Spanning Joints
No, not every hole in a plate spanning a joint needs to be filled with a screw—the key is achieving adequate fixation on each side of the joint or fracture with appropriate screw spacing and number, not filling every hole.
Core Principles of Screw Configuration
The evidence demonstrates that screw spacing and total number matter more than filling every hole. In biomechanical studies, wider screw spacing actually increases bending strength compared to clustering screws together 1. The critical factors are:
- Minimum 3 holes of plate length on each main fragment for most fractures
- At least 2-3 bicortical screws per fragment to achieve stable fixation
- Strategic screw placement directed toward the strongest bone (e.g., interosseous border in radius)
Specific Recommendations by Fracture Pattern
Simple Two-Fragment Fractures
- 2+2 configuration is sufficient: Two screws on each side of the fracture 2
- Screws should be placed in the holes closest to the fracture for maximum purchase
Comminuted or Inter-Fragment Zones
- 3+3 configuration: Three screws per fragment 2
- Avoid placing screws through the comminuted zone itself
Extensive Comminution or Segmental Fractures
- 4 screws per fragment maximum 2
- More screws beyond this do not improve outcomes and may increase complications
Critical Pitfall: Avoid Screws in High-Stress Zones
Do NOT place screws between prosthetic implants or in inter-prosthetic segments when prophylactically plating. Recent high-quality evidence shows that bicortical screws placed between apposing intramedullary implants create dangerous stress risers, resulting in significantly lower force-at-failure (4,831N vs 7.76N) and energy-to-failure (19.97J vs 7.76J) 3. This represents a 62% reduction in construct strength when inter-prosthetic screws are used.
Working Length Considerations
The concept of "working length" (empty holes near the fracture) has been extensively studied:
- Working length does not significantly affect healing or complications in clinical practice 4
- A 2026 study of 355 clavicle fractures found no association between the number of free plate holes and callus formation or complications 4
- Constructs with mechanical failure had fewer total screws (6.43 vs 7.14 screws), suggesting adequate screw number is more important than working length 4
Material-Specific Considerations
For titanium plates: Empty screw holes do not compromise fatigue strength, so leaving holes open around fracture sites is recommended 5
For stainless steel plates: Screw plugs can increase fatigue strength, but this is primarily relevant in laboratory settings 5
Practical Algorithm
- Identify the fracture pattern (simple vs comminuted)
- Ensure 3-hole minimum plate length on each fragment
- Place 2-3 screws per fragment for simple fractures, 3-4 for complex
- Direct screws toward strongest bone (longest trajectory possible)
- Leave inter-prosthetic zones empty if bridging implants
- Do not fill every hole—strategic placement trumps hole-filling
The outdated practice of filling every screw hole stems from older non-locking plate technology. Modern locking plates achieve angular stability without requiring every hole to be filled, and biomechanical evidence consistently shows that screw distribution and total number are the determinants of construct strength, not hole occupancy.