Huizhou Pengchengrui Technology Co., Ltd.

Normally, nickel titanium alloy bone screws implanted in a formal manner will not fall off or loosen on their own, and only in a few extreme cases will displacement or dislodgement occur.

1、 Why isn't it easy to fall off

1. Materials and fixing mechanism

Nickel titanium alloy bone screws are commonly designed with self tapping screws, compression screws, and anchor screws. After being screwed into the cortical bone, the threads firmly bite the bone; Combined with nickel titanium superelasticity and shape memory properties, continuous compression is applied to the fracture site after surgery, resulting in a tight fit between the nail and the bone.

2. Wrap and fix after bone healing

The fracture gradually heals, and new bone tissue grows around the screw, firmly embedding the nail body inside the bone, equivalent to permanent "embedding", and cannot fall out on its own.

3. Good biocompatibility

Nickel titanium alloy has no obvious rejection and will not be pushed out by tissues like foreign objects. There is very little occurrence of soft tissue erosion and nail body detachment.

Nickel titanium alloy bone nail

2、 What situations can cause loosening or detachment (truly 'nail dropping')

1. Early fractures often result in weight-bearing or vigorous activity before they fully recover (the most common)

1-3 months after surgery, the callus has not yet formed, and the fracture site is subjected to repeated stress due to premature, forceful, and significant movement. The screw continues to bear shear force, and the thread grinds the bone hole. The screw becomes loose, pulled out, and dislodged.

2. Poor bone condition

-Severe osteoporosis: extremely low bone density, insufficient gripping force of screw threads, easy to slip and loosen slowly;

-Comminuted fractures and bone defects: lack of intact cortical bone biting screws and missing fixation points.

3. Surgical operation issues

The expansion of the nail hole is too large, the selection of screw models is too short/thin, and the screwing depth is not enough, which makes the initial fixation unstable and prone to loosening and dislodging in the later stage.

4. Infection and bone non union

Deep infection of the incision can dissolve local bone and cause screws to lose their bony support; The fracture does not heal for a long time, the broken end continues to move slightly, the screw repeatedly becomes fatigued and loose, and in severe cases, the nail tail penetrates the skin.

5. Fatigue fracture ≠ nail drop

Nickel titanium has strong toughness, but long-term repeated stress may cause the nail to break. The distal end of the broken nail will remain in the bone and will not fall out, only the fixation will fail, not fall off.

3、 Does it count as' falling out 'when exposed or touching nails on the skin?

Many people mistakenly believe that touching the nail head on the skin means the nail has fallen off:

The tail of the screw is naturally left under the soft tissue on the surface of the bone. Thin people and superficial bones (fingers, metacarpals, ankles) can feel a protrusion under the skin, but the surface is visible. The screw is still stuck in the bone without loosening or falling off, so there is no need to be nervous.

4、 Practical advice

1. Follow the doctor's advice to brake and gradually recover. Do not apply force prematurely before the fracture heals;

2. Osteoporosis patients can receive synchronized anti osteoporosis treatment to improve screw grip;

3. After surgery, regular follow-up X-rays should be taken to visually observe whether the screws are displaced or loose;

4. Nickel titanium internal fixation devices can be retained in the body for life without the need for secondary surgery to remove them; If there is strong discomfort with the local foreign body in the later stage and it heals well, surgery can be scheduled to remove it.

Standardized surgery+normal rest: Almost no nail will fall off;

Violation of regulations, premature exertion, poor bone quality, and non union of infected bones are the reasons for screw loosening and dislodgement.