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®
Aesculap
Metha®
Metha® short stem prosthesis
Intended use
The implant is used
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as a component of a human hip endoprosthesis: Hip endoprosthesis stem
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to combine with Aesculap hip endoprosthesis components
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for implantation without bone cement
The short stem is available as either modular or non-modular implant.
The modular short stem consists of:
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Prosthesis stem
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Modular cone adapter
Materials
The materials used in the implant are listed on the packaging:
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ISOTAN®
Titanium forged alloy Ti6Al4V acc. to ISO5832-3
F
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ISODUR®
Cobalt-chromium forged alloy CoCrMo according to ISO 5832-12
F
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PLASMAPORE®
surface coating pure titanium acc. to ISO 5832-2 with additional calcium phosphate coating
µ-CaP
ISOTAN®, ISODUR® and PLASMAPORE® are registered trademarks of Aesculap AG, 78532 Tuttlingen / Germany.
Indications
Use for acute disorders of the hip that cannot be treated by other therapies:
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Degenerative osteoarthritis
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Rheumatic arthritis
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Femoral head necrosis
Contraindications
Do not use in the presence of:
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Joint diseases that can be treated by reconstructive surgery (e.g. displacement osteotomy)
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Acute or chronic periarticular or systemic infections
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Secondary diseases that could influence joint implant functionality
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Systemic conditions and metabolic disorders influencing the functioning of the joint implant
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Acute osteoporosis or osteomalacia
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Severely damaged bone structures that could prevent stable implantation of implant components
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Bone tumors in the region of implant fixation
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Bone malformations, defective axial positioning, or other bone conditions that rule out implantation of a hip-
joint prosthesis preserving the femoral neck
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Expected overload on the joint implant, especially due to high patient weight or major physical strains and activ-
ities
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Medicinal or other drug abuse or alcohol addiction affecting the functionality of the joint implant, especially
through temporary loss of control or impairment of the implant integration in the bone
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Expected lack of patient cooperation in dealing with the joint implant, especially during rehabilitation, and non-
compliance with doctors' recommendations
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Foreign body sensitivity to the implant materials
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Skeletal immaturity
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Neuromuscular diseases impairing the affected extremity
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Cups whose implantation, in analogy to ISO 21535:2002, result in a limited range of movement (less than 80°
in flexion/extension or less than 60° in abduction/adduction), e.g. Bipolar cup
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Prosthesis heads with neck length XL in combination with short stem prosthesis size 0 and 1
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Prosthesis heads with neck length XXL
Side effects and interactions
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Dislocation, loosening, wear, corrosion and fracture of implant components
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Joint dislocation and postoperative changes in leg length
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Primary and secondary infections
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Venous thrombosis, lung embolism, cardiac arrest
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Tissue reaction to implant materials
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Injury to blood vessels and nerves
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Hematomas and wound healing disorders
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Periarticular calcification
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Reduced joint mobility and flexibility
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Arthralgia and reduced tolerance for exercise
Safety notes
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It is the operating surgeon's responsibility to ensure that the surgical procedure is performed properly.
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General risk factors associated with surgical procedures are not described in this documentation.
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The operating surgeon must have a thorough command of both the hands-on and conceptual aspects of the
established operating techniques.
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The operating surgeon must be fully conversant with bone anatomy, including the pathways of nerves, blood ves-
sels, muscles, and tendons.
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It is the operating surgeon's responsibility to ensure the correct combination of implant components and their
implantation.
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Aesculap is not responsible for any complications arising from erroneous indication, wrong choice of implant,
incorrect combination of implant components and operating technique, the limitations of the treatment method,
or inadequate asepsis.
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The user instructions for individual Aesculap implant components must be followed.
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Do not, under any circumstances, combine implant components from different manufacturers.
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Do not, under any circumstances, use damaged or surgically excised components.
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Implants that have been used before must not be reused.
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Damage to load-bearing bone structures can result in loosening of the components, bone or implant fractures
or other acute complications.
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To ensure the earliest possible detection of such catalysts of implant dysfunction, the prosthetic joint must be
checked periodically, using appropriate techniques.
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Combine modular implant components only with suitable Aesculap hip endoprostheses.
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Observe material, friction coupling diameter and cone specifications.
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Observe further restrictions for combined implants.
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Avoid damage to the implant, especially in the neck or cone region, caused by instruments (e.g. HF surgical
devices) applied close to the implant.
Interactions between MRI and implant components!
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MRI examinations using magnetic fields of 1.5 and 3.0 tesla do not present an
additional risk to implant wearers.
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MRI causes non-critical, localized heat development.
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Implants produce moderate MRI artifacts.
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The implant components applied, along with their article numbers, the name of the implant, as well as the batch
number and serial number (if available) must be documented in all patient records.
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Postoperatively, individual patient information, as well as mobility and muscle training, is of particular impor-
tance.
Risk of implant component breakage due to combination with implant compo-
nents from other manufacturers!
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Use Aesculap implant components only.
CAUTION
Sterility
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The implant components come individually packed in protective packaging that is labeled according to its con-
tents.
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The implant components are gamma-sterilized.
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Store implant components in their original packaging. Remove them from their original protective packaging
only just prior to application.
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Prior to use, check the product expiry date and verify the integrity of the sterile packaging.
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Do not use implant components that are past their expiration date or whose packaging is damaged.
Damage to implants caused by processing and resterilization!
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Do not reprocess or resterilize the implants.
WARNING
Application
The operating surgeon shall devise an operation plan that specifies and accurately documents the following:
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Selection of the implant components and their dimensions
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Positioning of the implant components in the bone
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Location of intraoperative landmarks
The following conditions must be fulfilled prior to application:
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All requisite implant components are ready to hand
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Operating conditions are highly aseptic
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The implantation instruments, including the special Aesculap implant system instruments, are complete and in
working condition.
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The operating surgeon and operating room team are thoroughly conversant with the operating technique and
with the available range of implants and instruments; information materials on these subjects must be complete
and ready to hand.
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The operating surgeon is fully conversant with the rules governing medical practice, the current state of scientific
knowledge, and the contents of relevant scientific articles by medical authors.
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The manufacturer has been consulted if the preoperative situation was unclear and if implants were found in the
area operated on.
The surgical procedure and following information has been explained to the patient, and the patient's consent has
been documented:
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The functionality of the prosthetic joint is essentially inferior to that of the natural one.
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The prosthetic joint can bring about only limited improvement in the patient's condition vis-à-vis their condition
prior to the operation.
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The prosthetic joint can come loose due to excessive load, wear and tear, or infection.
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The lifespan of the prosthetic joint depends on the body weight and the load put on the joint.
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The prosthetic joint must not be subjected to overload through extreme strain, or through work-related or ath-
letic activities.
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Corrective surgery may become necessary if the implant loosens.
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In the event that corrective surgery is performed, it may not be possible under certain circumstances to restore
joint mobility and flexibility.
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The patient must undergo medical follow-up examinations of the prosthetic joint at regular intervals.
The implantation site is prepared in the following way:
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Following a high femoral neck osteotomy, open the femur with the implant-specific awl.
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Introduce the awl until it reaches the lateral corticalis.
Bone fractures/perforations in the implant bed will adversely affect the implant
fixation!
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Avoid bone fractures by applying careful surgical techniques.
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Treat bone fractures by appropriate intraoperative and postoperative thera-
WARNING
pies.
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Handle the implant components properly.
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Gradually prepare the implant bed with the implant-specific form rasps (starting with the smallest size).
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Check and, if necessary, correct the implant position, depth and antetorsion.
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Check the stem size against the form rasp that was introduced last in the correct position.
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Attach the rasp trail adapter and perform trial reduction with the appropriate trial heads; change rasp trial
adapter or trial heads as appropriate.
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Check the mobility/range of movement and stability of the joint and the length of the leg.
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Remove the trial implants and the rasp.
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When using the modular short stem, couple the prosthesis stem and the modular cone adapter prior to insertion.
Implant malfunction due to insufficiently fixated cone adapter!
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Fixate the modular cone adapter in the short stem by applying a hammer blow
and using instrument ND401R.
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Securely fixate the modular cone adapter in the short stem.
WARNING
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Insert the short stem (modular/non-modular) with specific insertion instruments.
Loosening of the cone adapter during insertion from applying blows to the Metha®
stem!
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Also perform the insertion procedure by applying blows to the cone adapter
with the cone protection cap applied.
WARNING
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