Cancellous Screws Specification, Uses & Sizes

Cancellous screws are designed specifically for use in the spongy, less dense, and trabecular bone tissue, commonly found at the ends of long bones, such as the femur and the tibia. This type of bone is also known as “cancellous” or “spongy” bone.

3.5 mm Locking Cancellous Screw

3.5 mm Cancellous Screw

4 mm Locking Cancellous Screw

4 mm Cancellous Screw

5 mm Locking Cancellous Screw

6.5 mm Locking Cancellous Screw

6.5 mm Cancellous Screw

Cancellous Screws Specification

Cancellous Screws available lengths are 10mm, 12mm, 14mm, 16mm1, 18mm, 20mm, 22mm, 24mm, 26mm, 28mm, 30mm, 32mm, 34mm, 36mm, 38mm, 40mm, 42mm, 44mm, 46mm, 48mm, 50mm, 55mm, 60mm, 65mm, 70mm, 75mm, 80mm, 85mm, 90mm, 95mm, 100mm, 105mm, 110mm, 115mm and 120mm.
Screws available thread lengths are 16 mm thread, 32 mm thread, Half Thread and Fully threaded.
Screw is made from pure Titanium and SS 316L.
Low-profile head helps reduce possibility of soft tissue irritation .
Reverse-cutting flutes assist in screw removal.
Choice of thread lengths offers best fit of threads into far bone fragment, for greater interfragmentary compression.
Cancellous thread profile uses deep cutting threads with a large pitch to increase resistance to pullout. The large pitch also accelerates screw insertion and removal.
Self-drilling, self-tapping screw tip facilitates screw insertion by eliminating the need for predrilling and tapping in most cases.
Any additional length sizes of this screw will be made on demand.
This is Self Tapping Screw. Self Tapping Screws cuts its own thread while being driven into the bone. It makes a small hole while entering the bone which creates a tight friction fit between the threads. This helps fight vibration loosening and allows the parts to be taken apart if needed..
Instruments are available for cancellous screws such as Bone Taps, Combined Drill & Tap Sleeve, Counter Sink, Depth Gauge, Drill Bits, Drill Guide, Drill Sleeve, Hollow Mill Screw Removal, Reverse Measuring Device, Screw Drivers and Screw Holding Forceps etc.

Cancellous Screws

Cancellous Screws uses

Cancellous Screws are designed specifically for use in the spongy, less dense, and trabecular bone tissue, commonly found at the ends of long bones, such as the femur and the tibia.
This Screw is also indicated for:

Femoral neck fractures
Slipped capital femoral epiphyses
Tibial plateau fractures
Ankle arthrodeses
Pediatric femoral neck fractures
Intercondylar femur fractures
Sacroiliac joint disruptions
Subtalar arthrodeses

Cancellous Screws advantage

Cancellous screws offer a number of characteristics that make them ideal for fastening bone fragments in this type of bone tissue:

Cancellous screws are typically coarse threaded with widely separated threads. This thread design enables better engagement and purchase in the softer, spongy bone, reducing screw loosening over time.
These screws frequently contain flutes along the shaft that aid in the removal of bone debris as the screw is introduced, lowering the danger of excessive pressure in the bone and promoting better fixation.
Some cancellous screws are self-tapping, which means they contain a cutting tip that can carve its own way in the bone without requiring a separate pilot hole. This feature can make the surgical procedure easier.
Cancellous screws are frequently partially threaded, with the unthreaded area near the screw head. This design allows the screw to squeeze the bone pieces while remaining stable

Cancellous screws are designed to optimize fixation in metaphyseal bone environments; however, certain clinical situations may require the substitution of cortical screws for use in cancellous bone, such as anatomic constraints, fragment size, or available instrumentation. Pullout strength and maximum insertion torque were both found to be greater for cancellous screws than cortical screws in all synthetic densities tested. The magnitude of difference in pullout strength between cortical and cancellous screws increased with decreasing synthetic bone density. Screw displacement prior to failure and total energy absorbed during pullout strength testing were also significantly greater for cancellous screws in osteoporotic models. Stiffness was greater for cancellous screws in standard and osteoporotic models. Cancellous screws have biomechanical advantages over cortical screws when used in metaphyseal bone, implying the ability to both achieve greater compression and resist displacement at the screw-plate interface. Surgeons should preferentially use cancellous over cortical screws in metaphyseal environments where cortical bone is insufficient for fixat

Cancellous Screws Contraindications

Contraindications may be qualified or total, and need to be taken into consideration when evaluating the prognosis in each case. The physician’s education, training and professional judgement must be relied upon to choose the most appropriate device and treatment. Conditions presenting an increased risk of failure include:

Any active or suspected latent infection or marked local inflammation in or about the affected area.
Compromised vascularity that would inhibit adequate blood supply to the fracture or the operative site.
Bone stock compromised by disease, infection or prior implantation that can not provide adequate support and/or fixation of the devices.
Material sensitivity, documented or suspected.
Obesity. An overweight or obese patient can produce loads on the implant that can lead to failure of the fixation of the device or to
failure of the device itself.
Patients having inadequate tissue coverage over the operative site.
Implant utilization that would interfere with anatomical structures or physiological performance.
Any mental or neuromuscular disorder which would create an unacceptable risk of fixation failure or complications in postoperative care.
Other medical or surgical conditions which would preclude the potential benefit of surgery.
All associated diseases which could endanger the function and success of the Cancellous Screws.

Warnings and Precautionary for Cancellous Screws

Before using Cancellous Screws, the surgeon and ancillary staff should study the safety information in these instructions, as well as any product-specific information in the product description, surgical procedures and/or brochures.

Screws are made from medical grade materials and are designed, constructed and produced with utmost care. These quality screws assure best working results provided they are used in the proper manner. Therefore, the following instructions for use and safety recommendations must be observed.

Improper use of screws can lead to damage to the tissue, premature wear, destruction of the instruments and injury to the operator, patients or other persons.

It is vital for the operating surgeon to take an active role in the medical management of their patients. The surgeon should thoroughly understand all aspects of the surgical procedure and instruments including their limitations. Care in appropriate selection and proper use of surgical instruments is the responsibility of the surgeon and the surgical team. Adequate surgical training should be completed before use of implants.

Factors which could impair the success of the operation:

Allergies to implanted materials.
Localized bone tumours.
Osteoporosis or osteomalacia.
System disease and metabolic disturbances.
Alcohol and drug abuse.
Physical activities involving excessive shocks, whereby the implant is exposed to blows and/or excessive loading.
Patients who are mentally unable to understand and comply with the doctor’s instructions.
Poor general health.

Possible Adverse Effects

The following adverse effects are the most common resulting from implantation:

Loosening of the Cancellous Screws, which may result from cyclic loading of the fixation site and/or tissue reaction of the implant.
Early and late infection.
Further bone fracture resulting from unusual stress or weakened bone substance.
Temporary or chronic neural damage resulting from pressure or hematomata.
Wound hematomas and delayed wound healing.
Vascular disease including venal thrombosis, pulmonary embolism and cardiac arrest.
Heterotopic ossification.
Pain and discomfort due to presence of the implants.
Mechanical failure of the implant, including bending, loosening or breakage.
Migration of implant resulting in injury.

Preoperative Planning for Cancellous Screws

The operating planning is carried out following a thorough clinical evaluation of the patient, Also, x-rays must be taken to allow a clear indication of the bony anatomy and associated deformities. At the time of the operation, the corresponding implantation instruments in addition to a complete set of implants must be available.

The clinician should discuss with the patient the possible risks and complications associated with the use of Cancellous Screws. It is important to determine pre-operatively whether the patient is allergic to any of the implant materials. Also, the patient needs to be informed that the performance of the device cannot be guaranteed as complications can affect the life expectancy of the device.

Cancellous Screws Precautions

Confirm functionality of instruments and check for wear during reprocessing. Replace worn or damaged instruments prior to use.
It is recommended to use the instruments identified for this Cancellous Screws.
Handle devices with care and dispose worn bone cutting instruments in a sharps container.
Always irrigate and apply suction for removal of debris potentially generated during implantation or removal.

Cancellous Screws Warnings

Cancellous Screws can break during use (when subjected to excessive forces). While the surgeon must make the final decision on removal of the broken part based on associated risk in doing so, we recommend that whenever possible and practical for the individual patient, the broken part should be removed. Be aware that implants are not as strong as native bone. Implants subjected to substantial loads may fail.
Instruments, screws and cut plates may have sharp edges or moving joints that may pinch or tear user’s glove or skin.
Take care to remove all fragments that are not fixated during the surgery.
While the surgeon must make the final decision on implant removal, we recommend that whenever possible and practical for the individual patient, fixation devices should be removed once their service as an aid to healing is accomplished. Implant removal should be followed by adequate post-operative management to avoid refracture.

Cancellous Screws General Adverse Events

As with all major surgical procedures, risks, side effects and adverse events can occur. While many possible reactions may occur, some of the most common include: Problems resulting from anesthesia and patient positioning (e.g. nausea, vomiting, dental injuries, neurological impairments, etc.), thrombosis, embolism, infection, nerve and/or tooth root damage or injury of other critical structures including blood vessels, excessive bleeding, damage to soft tissues incl. swelling, abnormal scar formation, functional impairment of the musculoskeletal system, pain, discomfort or abnormal sensation due to the presence of the device, allergy or hypersensitivity reactions, side effects associated with hardware prominence, loosening, bending, or breakage of the device, mal-union, non-union or delayed union which may lead to breakage of
the implant, reoperation.

Bone screws are the most commonly used orthopedic implants. There are many different types and sizes of screws for different types of bones. Most bone screws are made out of stainless steel or titanium alloys. The outer diameter, root diameter, and thread pitch and angle are important in determining screw mechanics.

In orthopedics, screws are typically described by their outer diameter, for example, a “4 mm Cancellous Screws” has an outside diameter of 4 mm. The pitch of a screw is the linear distance travelled by a screw for one full turn of the screw. The screw advances by a distance equal to the distance between the threads with each full turn. Cortical screws have a lower pitch and therefore more number of threads. Cancellous bone screws have a greater depth of the screw to increase the surface area and therefore improve the purchase, as the bone is weaker.

Screws function by converting the tightening torque into internal tension in the screw and elastic reactions in the surrounding bone. This creates compression between the fracture fragments that the screw is holding together. Screw is typically inserted into holes drilled equal to the root diameter and are either self-tapping or are inserted tapped (threaded) holes. The torque to insert cortical bone screws can be high, so the screws must be properly inserted into the correct size drilled hole and designed to withstand insertion torque levels expected in cortical bone. Cancellous bone screws have large, deep threads that grip the spongy bone well. Because of the relatively low strength of the cancellous bone, failure of the screw itself during insertion is rare, but pull out can be an issue.