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Technical Information sections:
 

   Technique Guides - A listing of some of our technique guides, brochures, wall charts, and inventory control forms.

   Care and Handling - A guide detailing specific warnings, precautions, adverse effects, sterility and implant usage.

   Materials - Details on the stainless steel used in our products.

   Implant Guide - Information on the plates and screws available in the DePuy Synthes catalog.

   Instrument Guide - Information on some common instrumentation available in the DePuy Synthes catalog.  

 


  

Suggestions Concerning Orthopedic Metallic Internal Fixation Devices

 

The use of metallic surgical implants has given the surgeon a means of bone fixation and helps generally in the management of fracture and reconstructive surgery; however, these implants are intended only to assist healing and not intended to replace normal body structures. Metallic bone fixation devices are internal splints which align the fracture while normal healing occurs. The size and shape of bones and soft tissue place limitations on the size and strength of implants. If there is delayed union or nonunion of bone in the presence of weight bearing or load bearing, the implant could eventually break due to metal fatigue. Therefore, it is important that immobilization of the fracture site be maintained until firm bony union (confirmed by clinical and radiographic examination) is established. All metallic surgical implants are subject to repeated stresses in use, even in the absence of direct weight bearing, which can result in metal fatigue. Factors such as the patient’s weight, activity level, and adherence to weight bearing or load bearing instructions have an effect on the stresses to which the implant is subjected, and therefore on the life of the implant.

 

The surgeon must be thoroughly knowledgeable not only in the medical and surgical aspects of the implant but also must be aware of the mechanical and metallurgical aspects of surgical implants. Postoperative care is extremely important. The patient must be warned that noncompliance with postoperative instructions could lead to loosening or breakage of the implant, and/or possibly migration, requiring revisional surgery.

 

The following are specific warnings, precautions, and adverse effects which must be understood by the surgeon and explained to the patient. These warnings do not include all adverse effects which could occur with surgery in general, but are important considerations particular to metallic internal fixation devices. General surgical risks should be explained to the patient prior to surgery.

 


Warnings

 

1. Correct selection of the implant is extremely important. The potential for success of fracture fixation is increased by the selection of the proper size, shape and design of the implant. While proper selection can help minimize risks, the size and shape of human bones present limitations on the size and strength of implants. Metallic internal fixation devices cannot withstand activity levels and/or loads equal to those placed on normal healthy bone, as these devices are not designed to withstand the unsupported stress of full weight bearing or load bearing.*

 

2. These devices can break when subjected to the increased loading associated with delayed union or nonunion. Internal fixation appliances are load sharing devices which hold a fracture in alignment until healing occurs. If healing is delayed, or does not occur, the implant could eventually break due to metal fatigue. Loads produced by weight bearing and activity levels will dictate the longevity of the implant. The patient should understand that stress on an implant can involve more than weight bearing. In the absence of solid bony union, the weight of the limb alone, muscular forces associated with moving a limb, or repeated stresses of apparent relatively small magnitude, can result in failure of the implant. Notches or scratches put in the implant during the course of surgery may also contribute to breakage.

 

3. Corrosion. Implanting metals and alloys in the human body subjects them to an aggressive chemical environment of salts, acids, and proteins which can cause corrosion. Dissimilar metals in contact with each other can accelerate the corrosion process due to galvanic corrosion effects. Thus, mixing of implant components from different manufacturers is not recommended, for metallurgical, mechanical and functional reasons.

 

4. Certain degenerative diseases or underlying physiological conditions such as diabetes or rheumatoid arthritis may alter the healing process, thereby increasing the risk of implant breakage.

 


Precautions

 

1. Surgical implants must never be reused. An explanted metal implant must never be reimplanted. Even though the device appears undamaged, it may have small defects and internal stress patterns which could lead to breakage.

 

2. Correct handling of the implant is extremely important. Contouring of metallic implants should be avoided where possible.

If contouring is necessary, or allowed by design, the surgeon should avoid sharp bends, reverse bends, or bending the device at a screw hole. The operating surgeon should avoid any notching or scratching of the device when contouring it. These factors may produce internal stresses which may become the focal point for eventual breakage of the implant.

 

3. Removal after fracture healing. Metallic implants can loosen, fracture, corrode, migrate, cause pain, or stress shield bone even after a fracture has healed, particularly in young, active patients. 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 postoperative management to avoid refracture. Note: Only the supplemental fixation component of a vertebral body replacement system should be removed after treatment of a vertebral body fracture and identification of the presence of fusion.

 

4. Adequately instruct the patient. Postoperative care and the patient’s ability and willingness to follow instructions are two of the most important aspects of successful fracture healing. This is particularly important should the device be used to treat an unstable fracture, such as intertrochanteric or subtrochanteric. The patient must be made aware of the limitations of the implant and that physical activity and full weight bearing or load bearing have been implicated in premature loosening, bending or fracture of internal fixation devices. The patient should understand that a metallic implant is not as strong as a normal, healthy bone and will fracture under normal weight bearing or load bearing in the absence of complete bone healing. Mental or physical impairment which compromises or prevents a patient’s ability to comply with necessary limitations or precautions may place that patient at a particular risk during postoperative rehabilitation.

 


Possible Adverse Effects

 

1. Nonunion or delayed union which can lead to breakage of the implant.

 

2. Metal sensitivity, or allergic reaction to a foreign body.

 

3. Limb shortening due to compression of the fracture or bone resorption.

 

4. Decrease in bone density.

 

5. Pain, discomfort, or abnormal sensations due to the presence of the device.

 

6. Nerve damage due to surgical trauma.

 

7. Necrosis of bone.

 

8. Vascular changes.

 


Sterility

 

Unless supplied sterile, metallic internal fixation devices must be sterilized prior to surgical use. Steam sterilization is recommended using the Association for the Advancement of Medical Instrumentation (AAMI) guideline “Good Hospital Practice: Steam Sterilization and Sterility Assurance.” The cycle parameters recommended in this standard are suggestions. It is the user’s responsibility to validate any steam sterilization parameters that are not provided directly by the manufacturer.



Implant Usage

 

The use of AO surgical implants has given the surgeon a means of stable internal fixation in the management of fractures and reconstructive surgery. However, the surgeon should be fully aware that AO implants are intended for use in internal fixation in accordance with techniques developed by the AO group. The products should not be used unless the surgeon is thoroughly familiar with the AO method as described in the Manual of Internal Fixation, M. E. Muller, et. al (Springer-Verlag: New York, Heidelberg, Berlin), AO Principles of Fracture Management, T. P. Ruedi and W. M. Murphy (Thieme: Stuttgart, New York), Manual of Internal Fixation in the Cranio-Facial Skeleton, L. A. Assael, et. al (Springer-Verlag: New York, Heidelberg, Berlin), and Small Fragment Set Manual, U. Helm and K. M. Pfeiffer (Springer-Verlag: New York, Heidelberg, Berlin). It is also recommended that surgeons utilizing these instruments and implants attend one of the various AO ASIF instructional courses offered periodically in North America and around the world.

 

Additional information regarding specific devices may be obtained from DePuy Synthes.