Lcp vs lcdcp orthopedic
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LCP vs LCDCP orthopedic plate comparison locking compression
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LCP vs LCDCP: A Detailed Comparison
Both are part of the AO plate evolution: DCP → LC-DCP → LCP. Understanding where they sit in this lineage is key to understanding their differences.
What Is the LC-DCP (Limited Contact Dynamic Compression Plate)?
The LC-DCP was introduced as a biological upgrade to the original DCP. Its defining features:
- Scalloped/undercut undersurface - reduces plate-to-bone contact by ~50% compared to the DCP. Bone contact only at screw hole edges, not between holes.
- Dynamic Compression Unit (DCU) holes - the same oval/eccentric holes of the DCP, allowing axial compression when screws are placed eccentrically.
- Uniform stiffness along its length - the undercuts between screw holes distribute stress evenly, reducing stress concentration at hole edges (unlike the DCP where stress risers are prominent at holes). Rockwood & Green specifically notes: "LC-DCP designs have more uniform stiffness along their length compared to standard plates, reducing stress concentrations located at the plate holes."
- Periosteal blood supply preservation - the reduced contact area limits devascularization of the cortex beneath the plate.
- Standard (non-locking) cortical screws only - no locking capability.
- Friction-dependent - stability relies on friction between plate and bone (compression interface).
- Healing: primary bone healing (direct cortical union) when absolute stability is achieved with compression.
What Is the LCP (Locking Compression Plate)?
The LCP is a later evolution that combines compression plating with internal fixator technology:
- Combi-hole design - each hole has two sections: a threaded locking portion and a DCU (oval) portion. This gives surgeons the choice to use either locking screws or conventional cortical screws in the same plate, or a combination (hybrid construct).
- Locking screws engage the threaded plate hole, creating a fixed-angle, load-sharing construct. The screw head locks to the plate, forming a "fixed-angle device."
- Internal fixator function - the LCP does NOT need to be pressed against the bone. It can be applied without periosteal contact at all ("bridging" mode), acting like an internal external fixator.
- Angular stability - locked screws act in parallel; the entire construct must fail simultaneously for pullout, unlike conventional screws that fail sequentially. This is especially important in osteoporotic bone.
- No friction dependence - stability is from the screw-plate interface, not plate-bone compression.
- The undersurface shape is identical to the LC-DCP (same undercuts), preserving periosteal blood supply similarly.
- Healing mode: secondary bone healing (callus) in bridge mode; primary if used in compression mode.
Side-by-Side Comparison Table
| Feature | LC-DCP | LCP |
|---|---|---|
| Screw type | Conventional cortical screws only | Locking screws AND/OR conventional screws |
| Hole design | DCU (oval) holes only | Combi-holes (threaded + DCU combined) |
| Plate-bone contact | Reduced (~50% less than DCP) | Same as LC-DCP (undercut design) |
| Stability mechanism | Plate-bone friction + screw purchase | Fixed-angle screw-plate interface (angular stability) |
| Functions as | Compression plate | Compression plate OR internal fixator |
| Bone quality | Good/normal bone | Works in osteoporotic bone |
| Need to contour plate | Yes - must be pressed to bone | No - can float above bone surface |
| Compression ability | Yes (DCU holes) | Yes (DCU portion of combi-hole) |
| Locking ability | No | Yes |
| Pullout resistance | Individual screw failure | All screws must fail simultaneously |
| Periosteal blood supply | Better than DCP | Same as LC-DCP |
| Working length | Fixed by hole position | Adjustable (skip holes without screws) |
| Healing type | Primary (absolute) or secondary | Primary or secondary depending on mode |
| Cost | Lower | Higher |
| Versatility | Less versatile | More versatile (hybrid constructs) |
Key Biomechanical Distinctions
1. Screw-plate interface:
- LC-DCP: screw head can toggle under load (conventional interface). Failure proceeds from one screw to the next.
- LCP (locked): screw head is rigidly engaged. Under loading, ALL locking screws must fail simultaneously for plate pullout - vastly superior in low bone density.
2. Plate needs to contact bone?
- LC-DCP: YES - must be properly contoured and applied flush to bone; friction is part of stability.
- LCP: NO - can be applied percutaneously with space between plate and bone; periosteal stripping is avoided.
3. Compression:
- Both can generate interfragmentary compression using the DCU (oval) portion.
- The LC-DCP compresses with all screws being conventional.
- The LCP can first compress with a conventional screw, then lock with locking screws for added stability (hybrid technique).
4. Stiffness:
- LC-DCP: uniform stiffness due to undercuts, but construct stiffness is affected by bone quality.
- LCP in full locked mode: very high stiffness - can sometimes be TOO stiff, inhibiting callus formation. Hence the development of "far cortical locking" (FCL) techniques to modulate stiffness.
Clinical Indications
| Situation | Preferred Plate |
|---|---|
| Simple transverse/oblique fractures in good bone | LC-DCP (compression mode) |
| Diaphyseal humeral fractures | 4.5 mm LC-DCP (3-4 holes each side) |
| Osteoporotic fractures | LCP (locked mode) |
| Periarticular/metaphyseal fractures | LCP (anatomic precontoured) |
| Short metaphyseal segments | LCP |
| Comminuted fractures (bridge plating) | LCP |
| Periprosthetic fractures | LC-DCP or site-specific LCP with cables |
| Nonunions (e.g., humeral) | Either DCP/LC-DCP/LCP + fibular allograft |
| Minimally invasive percutaneous plating (MIPO) | LCP (does not need bone contact) |
Summary
The LC-DCP is a conventional compression plate with improved biology (less periosteal damage) and better stress distribution than the original DCP. It is reliable and cost-effective in good bone quality.
The LCP is a hybrid device that incorporates all the benefits of the LC-DCP while adding the capacity for fixed-angle locking. This makes it superior in osteoporotic bone, short metaphyseal segments, and minimally invasive approaches. The locking screw-plate interface transforms the plate into an internal fixator that does not rely on plate-bone friction.
In essence: the LCP does everything the LC-DCP does, plus locking - but at higher cost and with the risk of excessively stiff constructs if not used correctly.
- Rockwood and Green's Fractures in Adults, 10th ed. 2025, p. 486 (Locked Plating section)
- Rockwood and Green's Fractures in Adults, 10th ed. 2025, p. 496 (Modulation of Implant Stiffness / LC-DCP design)
- Campbell's Operative Orthopaedics, 15th ed. 2026 (Technique 64.3)
- DCP principles and LCP comparison - nx-medical.com
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