The short stem hip system Surgical Technique

Transcription

1 The short stem hip system Surgical Technique

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3 The short stem hip system cementless The Aida hip system was developed in co-operation with the Aida inventors group, founded by surgeons of 10 surgical department throughout Germany. Table of Contents INTRODUCTION... 2 SURGICAL TECHNIQUE... 3 IMPLANTS... 9 INSTRUMENTS MEDICAL INFORMATION Nota Bene: The described surgical technique is the suggested treatment for the uncomplicated procedure. In the final analysis the preferred treatment is that which addresses the needs of the individual patient. Copyright note: Aida, Cepthar, ACS, Dia, Eco, Betha, LOAD, implavit, implacross and implatan are registered trademarks of implantcast GmbH. The use and copy of the content of this brochure are only allowed with prior permit given by the implantcast GmbH.

4 total hip system Introduction The Aida hip system includes cementless short stem implants of 8 sizes with two different offsets each (standard and lateralised). The implants are made of implatan TiAl 6 V 4 - titanium alloy with a proximal dual coating of cpti (pure titanium) and HA. In a finite element analysis the Aida System has shown an outstanding primary fixation design which shows conformity to the demands of a modern type short stem hip system. Extract from the study FEA of bone remodelling process for Aida prosthesis, Patna, India 14.October 2007 Further the Aida stem shows a minimal reduction of the trabecular load in the greater trochanter. The Stress-shielding is lower in comparison to the 2D calculation of the Mayo Prosthesis. Also in the sagittal plane there is only a small change of the bone density observed A similar outcome is expected for the Mayo Prosthesis, as this system is replacing the same volume of the proximal femur. The system shows a smaller amount of Stress-shielding in the area of the greater trochanter as the Mayo Prosthesis. Due to this the Aida could be preferable over the Mayo Prosthesis. But to not jump conclusions at this stage one have to consider that the difference of geometries of femoral bones may lead to different changes of the bone density gradients. Nevertheless the Aida system can be respected as an excellent alternative to the Mayo Prosthesis. 2

5 total hip system Femoral osteotomy Due to the preoperative planning the neck of the femur is resected. To align the osteotomy you can use the resection templates (fig.1). Preparation of the acetabular bone If the preparation of the acetabular bone is necessary, please consider the surgical technique provided in conjunction with the preferred implant. figure 1 Opening of the femoral canal Please use the special awl to open the intramedullary canal (fig. 2). figure 2 3

6 total hip system Broaching of the femoral canal Begin with the smallest broach to prepare the intramedullary bone. Enlarge the bone preparation with the broaches of increasing sizes until you reach the size of the preoperatively chosen stem size (fig. 3). figure 3 Remove the broach handle (fig. 4). Leave the broach in place for trialing purposes. figure 4 4

7 total hip system Trial reduction Attach the trial neck standard (fig. 5a) and the trail head (28 mm or 32 mm) of the length medium (fig. 6). Reduce the joint and check the range of motion as well as the stability of the joint. figure 5a If necessary replace the trial neck by the trial neck lateralised (fig. 5b) or a head of a different neck length and check again the range of motion. If sufficient stabilization is achieved, remove all instruments and trial components. figure 5b x-ray image of the broach in the femur figure 6 5

8 total hip system Implantation of the Aida stem Choose the Aida stem of the correct size and insert the stem by using the stem impactor (fig. 7). figure 7 6

9 total hip system Impaction of the head It is optional to perform a final stability and range of motion test. Therefore insert a trial head of the formally used neck length (fig 8). Clean and dry the taper (12/14) and add the original head to the taper of the stem. Use the head implants with a few strokes of a mallet to secure the taper connection (fig. 9). figure 8 figure 9 7

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11 total hip system IMPLANTS Aida stem, cementless, standard implatan TiAl 6 V 4 -wrought alloy acc. to DIN ISO 5832/3 with CpTi-coating acc. to DIN ISO 5832/2 and HA- coating REF size Aida stem, cementless, lateralised implatan TiAl 6 V 4 -wrought alloy acc. to DIN ISO 5832/3 with CpTi-coating acc. to DIN ISO 5832/2 and HA- coating REF size Aida instrument container Aida instrument container GIS

12 total hip system INSTRUMENTS Aida modularer broach handle Aida broach modular Größe Größe Größe Größe Größe Größe Größe Größe 8 Aida trial neck standard lateralised Aida awl bowed stem impactor trial head mm S mm M mm L mm XL mm S mm M mm L mm XL head impactor Resection template

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14 IMPORTANT MEDICAL INFORMATION 1. Packing unity/product name This information concerns: hip prosthesis according to ISO 5832/1, /3, /4, /11 or /12 femoral heads according to ISO 5832/1, /3, /4, /9 or /12 acetabular cups according to ISO 5832/3 or 4 acetabular cups and inlays according to ISO 5834/2 bipolar heads according to ISO 5832/1 or /3 with ISO 5832/4 acetabularcups or liners according to ISO 5834/2 Biolox forte liners according to ISO 6474 Biolox forte femoral heads according to ISO 6474 reconstruction acetabular implants acc. to ISO 5832/1 Cement restrictors acc. to ISO 5834/2 or gelatine Bone screws according to ISO 5832/3 or /1 Golden femoral heads are coated with a ceramic TiN-coating A few of the cemented hip prostheses are combined with centralisers of PMMA. The x-ray implants are titanium alloy according to ISO 5832/3 or 5832/1. Product name, size, article number and lot number are indicated on the product label and the enclosed interior labels. We recommend to put the interior labels onto the patient file or the surgical report. 2. Introductory remarks This prosthesis must only be implanted by persons whose skills can due to their training, know-how and practical experience guarantee for a proper use of the system. This user information can only provide some of the basic information necessary for the use of the product. Further information is available from the manufacturer. Prior to surgery the surgeon must work out a surgical plan comprising the dimensions of the prosthesis and the positioning of the implant components in the patient s bone. It must be assured that: all necessary implant components are present the corresponding instrument set is complete Never reused implants which have already been implanted or removed, even if it appears undamaged, former stress could have lead to conditions which might cause a mechanical defect. The use of a new prosthesis of the respectively latest type is recommended. 3. Packaging and sterility All implant components are packaged separately in sealed triple-peel pouches or double blister packaging. Metal components have been sterilized by gamma radiation (min. 25 kgy). All polyethylene components have been sterilised by EtO-Gas or by gamma radiation (min. 25 kgy). The individual sterlisation method is indicated on the product labelling. The red point on the second protective cover indicates the performed radiation sterilisation and the green point for EtO sterilisation. The outer cover is for protection only. Please always take note of the expiry date, indicated behind the symbol.. After expiry of this date the product must not be implanted any more. 4. Resterilisation if they consist of Polyethylene or DLPLA or gelatine, partly or entirely, if they are coated, partly or entirely, if they have any kind of defect, no matter of what kind or size, if they have been implanted before. Resterilisation is to be performed by autoclave. Sterilization quality must be secured by appropriate test procedures. Original packaging must not be reused and must be replaced by appropriate autoclave packaging. Implants must never be sterilized assembled (e.g. head and shaft). This can lead to (possibly invisible) component defects. All coated and polished surfaces are to be protected during resterilisation. Standard cleaning methods offer no guarantee for the removal of pollution from porous surfaces. The correct setting of the autoclave must be checked regularly. 5. Operation and storage The implant should always be kept in its original packaging, in an adequate storing room for sterile products. Before use of the implant the packaging must be checked for damages. The product remains sterile as long as the packaging has not been opened or damaged and before passing the expiry date. When removing the implant from the packaging please make sure that the actual implant corresponds to the information given on the label on the cover (concerning lot-no. and size). Please follow the appropriate aseptic instructions when removing the packaging from the implant. The implant surface is extremely sensitive. The implants must not get in touch with objects which may damage their surface. Manipulation or bending of an implant can not only shorten its lifetime, under stress it can also cause an implant failure, immediately or after a certain period of time. Any manipulation of the implant affects its performance and must therefore be avoided. Before implantation the implant must be checked visually for possible defects. Damaged implants must not be used. The use of bone cement is subject to the operational instructions of the respective manufacturer. Bone cement must not get in touch with or remain on the sensitive articular surface, neither intraoperatively nor postoperatively. All extruded cement must be carefully removed to make sure no remains can migrate to the articular surface. This could lead to increased wear or to severe damage and failure of single implant components. For cementless insertion a solid fixation during the surgical procedure is of major importance for the success of the operation. The fixation of the femoral shaft within the prepared femur must be performed under pressure (press fit). This requires a precise handling and the use of special instruments. A reliable fit of the cone interfaces can only be achieved if the surfaces of the femoral head and the cone of the respective prosthesis are completely intact. Both cones must in any case correspond in size. Ceramic heads must only be attached to brand new cones. The cone of the respective prosthesis must be cleaned and dried before being attached. For an intraoperative femoral head exchange a metal head must be selected, provided that the cone of the prosthesis shows no signs of damage. Should a cone damaged, the prosthesis must be replaced. The manufacturer only guarantees for implants which have been implanted directly after removal of the original packaging. We do not accept any reliabilities for resterilised products. 12 The following recommendations are only provided for your information: Implants must not be resterilised

15 IMPORTANT MEDICAL INFORMATION 6. Compatibility The latest manufacturing and testing procedures guarantee for a compatibility of any ic-implant with another ic-implant of corresponding size (diameter, cone-dimensions, inlay-size etc.), regardless their manufacturing date. The correspondence of the exterior diameter of the acetabular and femoral head components (28 and 32 mm), as well as of the cones of head and shaft (cone 12/14) must always be carefully checked. For one and the same acetabular type there are often several inlay-types available (different interior diameters). The icacetabular inlays must only be combined with ic-metal components of the same type. All ic hip stems or acetabulum shells are certified for the use of Biolox forte ceramic heads or liners. Moreover, due to standardization on the endoprosthesis market, the ic-implants are compatible to and can replace those of other manufacturers and distributors. On request, the manufacturer can give information on the compatibility to a certain product. If there is any doubt, the diameter of the articular surfaces and the fit of the femoral heads (exterior diameter) and acetabuli (interior diameter) should be checked or made sure with the respective instruments before the actual insertion. 7. Indications Prior to the decision to implant an arthroplasty the results of all examinations must be considered thoroughly. An arthroplasty is only indicated if the prospective success of all other conservative and surgical therapeutical alternatives is considerably lower than that of an arthroplasty. Careful preoperative planning and a precise surgical technique are necessary to obtain optimal results. In order to minimize the danger of postoperative complications different factors must be considered, i.e. the anatomical stress situation, the soft tissue basis and the features of the bony implant bearing. On the basis of the a.m. principles indications for an arthroplasty are: severe articular destruction with considerably restricted mobility, if other therapeutical steps are not promising. a prospective long-life result of the planned implantation also with respect to the patient s weight, age and physical activity. severe arthropathy due to degenerative and rheumatoid arthritis, articular fractures or osteonecrosis. postoperative conditions requiring revision surgery after operations with or without implantation of an arthroplasty. 8. Contraindications The lifetime of an endoprosthesis can be limited because of biological, material-specific and biomechanical factors. Therefore the indication of an arthroplasty must be carefully considered for obese patients, in cases of extraordinary stress on the articulation due to excessive physical activity and for any patient below 60 years of age. Moreover, special attention must be directed to patients with allergies to one or several component materials and to patients suffering from mental illness or neurosis, which may affect their ability to follow the restrictions in activity. Further, the success of the operation can be affected by acute or chronical infections extensive bone defects or inadequate bone quality, making the implantation or a solid primary fixation of the implant impossible neurogenous arthropathy severe myopathy, neuropathy or angiopathy of the respective extremity prospective overload or excessive forces on the implant excessive physical activity or strain accidental falling or other joint resultant forces severe osteoporosis bone tumors in the implant fixation area severe deformity or defective axial position metabolic disorders/allergies drug addiction and abuse (alcohol!) The patient must be informed about the implant s stress limitations and the possible consequences resulting from the a.m. conditions with regard to the surgical success. Stress bearing of an implant can never be the same as for a healthy physiological bone structure. The patient must be warned of the consequences of excessive stress on the implant especially before the end of the postoperative healing process. All information given to the patient should be documented in writing by the surgeon. 9. Complications The complications and negative consequences listed below are some of the most typical and most common adverse effects of hip surgeries: device component loosening, distortion or fracture. These effects rarely occur and are normally caused by one or several of the mentioned loosening factors, listed above or below, under contraindications and warnings, acute postoperative wound infection and delayed infection, possibly leading to sepsis, migration or subluxation of the implant resulting in reduced mobility, increased or decreased leg length or bone wear, bone fractures due to unilateral stress bearing, cardiovascular disorders, e.g. thrombosis and embolism, wound haematoma and delayed healing process, temporary or persistent neurological disorders, tissue reaction due to allergies or foreign body-reactions caused by frictional particles, myositis ossificans. Please give us notice in the case of any complications related to the use of our implants and instruments. Manufacturer and distributor of the system cannot accept any reliability for any complications or negative effects arising from mistakes in indication, from improper surgical techniques, inadequate material selection or handling or from asepsis. All these effects are subject to the surgeons s responsibility. implantcast GmbH Lüneburger Schanze 26 D Buxtehude, Germany phone : fax : info@implantcast.de internet : Technical modifications are subject to change without notice. All implants have been developed, manufactured and tested according to latest technical standards. No part of this document may be duplicated without prior consent of implantcast GmbH. 13

16 Your local distributor: implantcast GmbH Lüneburger Schanze 26 D Buxtehude Germany phone: fax: internet: AIDAOPE *+E1ICAIDAOPE++* *+$$E1IC *