Cannulated cancellous screw: Definition, Uses, and Clinical Overview

Cannulated cancellous screw Introduction (What it is)

A Cannulated cancellous screw is an orthopedic screw designed to fix broken or unstable bone.
“Cannulated” means it is hollow so it can slide over a guidewire for precise placement.
“Cancellous” refers to spongy bone (often near joint ends), where this screw is commonly used.
It is frequently used around the hip, including certain femoral neck fractures and other peri‑articular injuries.

Why Cannulated cancellous screw used (Purpose / benefits)

A Cannulated cancellous screw is used to stabilize bone so it can heal in the correct position. In orthopedics, this is called internal fixation—holding bone fragments together from inside the body using implants.

Common goals include:

• Fracture stabilization: Reducing movement at a fracture site so the body’s normal bone-healing process can proceed.
• Maintaining alignment: Helping keep bone fragments positioned correctly after a reduction (realignment).
• Compression across a fracture or fusion site: Many cancellous screws are designed to pull bone surfaces together (compression), which can support healing in selected patterns of injury.
• Less disruptive placement in some cases: The cannulated design allows insertion over a guidewire, which can help with accuracy and may reduce the need for extensive exposure in certain operations.
• Adaptability near joints: Cancellous bone is common near joints (including the hip), and this screw type is designed to gain purchase in that spongier bone.

The “problem it solves” is primarily mechanical instability—when a fracture or surgical bone cut cannot reliably heal because it is moving, malaligned, or unable to maintain contact between surfaces.

Indications (When orthopedic clinicians use it)

Orthopedic clinicians may use a Cannulated cancellous screw in scenarios such as:

• Selected femoral neck fractures (hip fractures) where screw fixation is appropriate
• Fixation of certain hip-related injuries requiring precise screw placement (varies by clinician and case)
• Temporary or definitive fixation after a reduction of a fracture near a joint
• Fixation in cancellous bone regions (for example, near the ends of long bones)
• Certain osteotomies (surgically created bone cuts) that need stabilization during healing
• Some foot, ankle, knee, wrist, or shoulder fractures where cancellous bone purchase and guidewire placement are helpful (use varies by anatomy and fracture pattern)

Contraindications / when it’s NOT ideal

A Cannulated cancellous screw may be less suitable, or require a different strategy, in situations such as:

• Fractures with severe comminution (many fragments) where screw fixation alone may not control stability well
• Poor bone quality (for example, significant osteoporosis) where screw purchase may be limited and another construct may be preferred
• Active infection at or near the surgical site, where implant choice and timing may differ
• Fracture patterns needing a different implant (for example, a sliding hip screw, plate-and-screw construct, intramedullary nail, or arthroplasty), depending on location and stability needs
• Inadequate ability to achieve or maintain reduction, when the bone cannot be aligned acceptably for screw fixation
• Soft-tissue or skin compromise that changes surgical approach options
• Patient- or situation-specific constraints (for example, anticipated difficulty following rehabilitation restrictions), where an alternate method may better match goals and risks (varies by clinician and case)

How it works (Mechanism / physiology)

Biomechanical principle

A Cannulated cancellous screw works by converting the screw’s thread purchase into stability between bone segments. Once positioned, it helps resist:

• Shear (sliding forces)
• Bending (angulation forces)
• Rotational motion (twisting)

Many cancellous screws are partially threaded, which can create interfragmentary compression: the threaded portion grips one side of the fracture while the smooth shaft allows the other side to slide, pulling the fragments together as the screw is tightened. Fully threaded versions may be used when compression is not desired or when maintaining length is important.

The cannulation (hollow center) allows the screw to be advanced over a guidewire, supporting accurate trajectory and positioning.

Relevant hip anatomy and tissues

In hip applications, these screws may be used across portions of the proximal femur, including:

• The femoral head (ball)
• The femoral neck (narrow bridge between head and shaft)
• The intertrochanteric region (between bony prominences below the neck), in selected patterns

Nearby structures that matter clinically include:

• Articular cartilage of the hip joint (a smooth surface that should not be violated)
• Blood supply to the femoral head, which is a key consideration in certain femoral neck fractures (risk considerations vary by fracture type and timing)
• Cancellous bone inside the femoral head/neck, where the threads are designed to hold
• Cortical bone (hard outer shell), which may be engaged depending on screw path and design

Onset, duration, and reversibility

A Cannulated cancellous screw provides immediate mechanical stability once implanted. Its benefit lasts as long as fixation is needed—often until the bone heals. The implant may be left in place long term or removed later if clinically indicated; removal decisions vary by symptoms, location, and surgeon preference. It is not “reversible” in the way a medication is, but it is surgically removable.

Cannulated cancellous screw Procedure overview (How it’s applied)

A Cannulated cancellous screw is an implant, not a stand-alone procedure. It is typically used during an orthopedic fixation surgery. A high-level workflow often includes:

1. Evaluation / exam – Clinical assessment and imaging (commonly X-ray; sometimes CT or MRI depending on the scenario) – Classification of the fracture pattern and stability – Discussion of general treatment options and goals (varies by clinician and case)

2. Preparation – Surgical planning: number of screws, screw trajectory, and whether washers or other components are needed – Anesthesia planning and patient positioning – Sterile preparation of the operative field

3. Intervention – Reduction (realignment) of the fracture if displaced – Placement of one or more guidewires to establish the planned paths – Measuring and selecting screw length/diameter – Insertion of the Cannulated cancellous screw(s) over guidewires, sometimes to create compression across the fracture

4. Immediate checks – Imaging confirmation (often fluoroscopy during surgery) to confirm position, length, and joint safety – Verification of stability and alignment

5. Follow-up – Postoperative imaging at intervals to assess healing – Rehabilitation planning and progression of activity and weight-bearing status as healing allows (varies by clinician and case)

Types / variations

Cannulated cancellous screws come in multiple designs. Common variations include:

• Partially threaded vs fully threaded
• Partially threaded designs are often chosen when compression across a fracture or fusion site is desired.

• Fully threaded designs may be used when maintaining length or avoiding compression is preferred.

• Diameter and length options

• Sizes vary by anatomy (hip vs ankle vs wrist) and by manufacturer.

• Thread design

• Differences in pitch and depth affect purchase in cancellous bone; performance can vary by material and manufacturer.

• Headed vs headless (compression) designs

• Some screws have a prominent head; others are designed to sit more flush in bone to reduce hardware prominence in selected locations.

• With or without washers

• Washers can increase surface area under the screw head, which may help in softer bone or thin cortical areas (use varies by case).

• Self-tapping vs non-self-tapping

• Self-tapping screws can cut their own thread path; others require tapping.

• Material

• Common materials include stainless steel and titanium alloys; MRI behavior, stiffness, and artifact can differ by material and design (varies by material and manufacturer).

• Cannulation size / guidewire compatibility

• The hollow channel is sized to match specific guidewires; systems are typically brand-specific.

Pros and cons

Pros:

• Enables precise placement using a guidewire (cannulated design)
• Often allows controlled compression across selected fracture patterns (especially partially threaded designs)
• Designed for purchase in cancellous bone, common near joints
• Can be used in multiple-screw constructs to improve rotational control in certain fractures
• Widely used with standard imaging guidance in orthopedic operating rooms
• May be combined with other fixation methods when needed (varies by clinician and case)

Cons:

• Not ideal for all fracture patterns, especially highly unstable or comminuted injuries
• Fixation strength can be limited by bone quality and fragment size
• Malposition can risk joint penetration or inadequate stability, so imaging and technique are critical
• Hardware may cause irritation or prominence depending on location and patient anatomy
• There is a risk of hardware failure (bending, loosening, breakage) if healing is delayed or loads exceed construct capacity (risk varies by case)
• Sometimes requires later removal if symptomatic or if it interferes with future procedures (varies by clinician and case)

Aftercare & longevity

Aftercare depends on the underlying injury, the bone involved, and the stability achieved. In general, outcomes and longevity are influenced by:

• Fracture type and displacement: More complex fractures often require closer monitoring and may have different healing timelines.
• Quality of reduction and screw position: Alignment and implant placement can influence stability and healing potential.
• Bone quality: Osteoporosis or other bone health conditions can affect fixation purchase and healing.
• Number and configuration of screws: Some injuries use multiple screws to improve stability; the optimal configuration varies by clinician and case.
• Weight-bearing and activity level: Early loading may be restricted in some situations to protect fixation; timelines vary by clinician and case.
• Rehabilitation participation: Restoring strength, mobility, and gait mechanics can affect functional recovery.
• Smoking status, nutrition, and metabolic health: General health factors can influence bone healing.
• Follow-up imaging and visits: Monitoring helps assess progress and identify issues such as loss of fixation or delayed union.

Regarding longevity, the screw is intended to support the bone until healing occurs. Some people keep the implant indefinitely without problems, while others may have removal for symptoms, specific complications, or future surgical planning; this varies by clinician and case.

Alternatives / comparisons

The “best” fixation method depends on anatomy, fracture stability, bone quality, and patient goals. Common alternatives or comparisons include:

• Nonoperative management (observation/immobilization)
• Considered for selected stable injuries or when surgical risk is high.

• May involve activity modification and close imaging follow-up; suitability depends on fracture type and displacement.

• Non-cannulated screws

• Traditional solid screws can provide fixation without a guidewire-based system.

• Cannulated systems may offer easier guided placement, while solid screws may have different strength characteristics depending on design (varies by manufacturer).

• Plate-and-screw constructs

• Plates can provide buttress support and improved control of complex fracture mechanics.

• Often used when a single or multiple cancellous screw construct is not sufficient.

• Sliding hip screw (dynamic hip screw)

• Commonly used for certain proximal femur fracture patterns where controlled collapse and strong lateral support are needed.

• Implant choice depends heavily on fracture location and stability.

• Intramedullary nail

• Often used for certain femur fracture patterns, providing a load-sharing device within the bone canal.

• Can be preferred in some unstable patterns; the decision is case-dependent.

• Hip arthroplasty (partial or total hip replacement)

• In some hip fractures, especially when fixation is unlikely to succeed or when joint surfaces are compromised, replacement may be considered.

• This is a different strategy with different goals and risks; selection varies by clinician and case.

• External fixation

• Less common for many hip applications, but used in certain trauma or soft-tissue situations as temporary or staged stabilization.

Cannulated cancellous screw Common questions (FAQ)

Q: Is a Cannulated cancellous screw the same as a “hip pin”?
In everyday language, “hip pinning” can refer to placing screws across certain hip fractures, especially femoral neck fractures. A Cannulated cancellous screw is one of the common implants used for that purpose. The exact implant and configuration depend on the fracture pattern and surgeon preference.

Q: Will I feel the screw inside my hip or bone?
Many people do not feel internal screws directly once tissues heal. Some may notice discomfort related to hardware prominence, local irritation, or activity, depending on location and body anatomy. Whether symptoms occur varies by clinician and case.

Q: How long does the screw stay in place?
Often the implant is intended to remain at least until the bone heals. In some cases it stays permanently; in other cases it is removed later due to symptoms, specific complications, or future surgical needs. Timing and necessity of removal vary by clinician and case.

Q: Is it safe to have an MRI with a Cannulated cancellous screw?
Many modern orthopedic implants are MRI-compatible under specific conditions, but compatibility depends on the exact material and manufacturer. MRI can also produce image artifact near metal, which can limit detail around the implant. Imaging staff typically verify implant information when MRI is being considered.

Q: Does placement hurt after surgery?
After fixation surgery, pain can come from the fracture itself, surgical soft-tissue irritation, and normal postoperative inflammation. Pain experience and duration vary widely by individual and injury severity. Clinicians typically use a multimodal pain-control approach, but specific medication choices are individualized.

Q: When can someone drive or return to work after fixation with these screws?
Return to driving or work depends on which side was treated, pain control, mobility, reaction time, and job demands. For physically demanding work, timelines may be longer than for sedentary roles. Clearance criteria vary by clinician and case.

Q: Will I be allowed to put weight on the leg right away?
Weight-bearing status is determined by fracture stability, fixation quality, and healing expectations. Some cases allow earlier weight-bearing, while others require restriction to protect the repair. Specific instructions vary by clinician and case.

Q: What is the cost of surgery involving a Cannulated cancellous screw?
Total cost can vary widely based on hospital setting, region, insurance coverage, surgeon and facility fees, imaging, anesthesia, and rehabilitation needs. Implant pricing also varies by material and manufacturer. A treating facility can provide the most accurate estimate.

Q: What are common reasons a screw fixation might fail?
Potential contributors include inadequate stability for the fracture pattern, poor bone quality, delayed healing, infection, or excessive loading before healing. Technical factors like screw position and fracture reduction quality also matter. Risk levels vary by clinician and case.