Introduction to the Bertram Hip Spacer

1 Introduction to the Bertram Hip SpacerApproximately 200,000 hip replacement surgeries are done everyyear in United States. Fortunately the incidence of infection isroutinely percent-1 percent. However this still leaves a largenumber of patients whose prostheses become infected. If one wereto take a ten-year period of time, and accumulate a 1 percentinfection rate per year for 10 years, one can appreciate the incidenceof infected total hip prosthesis. Using this scenario there may be asmany as 20,000 infected hip prostheses at any one time in UnitedStates. A more recent number quoted in the AAOS- OKU SpecialtySeries Hip and Knee Reconstruction manual is over 10,000 patientsin the United States in any one year.

2 This was based on a 1%lifetime of the prosthesis infection accepted method of treatment currently, for an infected total hipprosthesis, is the exchange Arthroplasty technique. This involves theremoval of the infected components and insertion of an antibioticimpregnated Spacer . This current method of treatment carriesapproximally an 85-90 percent success rate. The difficulty with thismethod is that the patient usually has an ill fitting Spacer in place, hasvery poor function with regards to hip mechanics, and has asignificant amount pain during this six to eight week interval beforereimplantation.

3 Upon subsequent conversion, it is always difficult torestore the length of the limb, because of the shortening of the femurduring the six to eight week period of time that the Spacer has been inplace. The reason for this is that the surgeon only has 10 to 12minutes to mold a prosthesis which can fit the patient. This is doneby hand, and rarely is the surgeon able to make a functionalprosthesis by hand. It is extremely difficult to mold a unipolarcomponent which can fit not only the canal but the acetabulum. It isalso nearly impossible to mold a correct neck shaft angle as well asoffset which will be functional.

4 Any attempt to make an acetabularcomponent which articulates with a femoral component usuallydislocates. Most of the time most surgeons simply place a string ofantibiotic impregnated beads in the hip space, which have nofunctional this time I have designed to a solution to this problem. What weare providing is a mold with an anterior and posterior half, which is fittogether tightly to form a seal, leaving a cavity in the middle which isin the shape of a unipolar prosthesis. We have chosen the size of thefemoral stem and acetabular component based on the use ofprostheses throughout the country, giving us the most common sizesof the femoral and acetabular portions of the unipolar cementprosthesis.

5 Current sizes for this unipolar Spacer are as LengthFemoralStem SizeFemoral StemLength352 mm35 mm13 mm140 mm55640151607604517180 Neck Shaft Angle for all implants is 127 degreesThe technique involves fitting the anterior and posterior halves of thewax mold together on the back table. There is an opening on themold into which the nozzle of a standard cement gun will fit. Thecement is then injected into the mold, filling the mold first distally, andthen proximally forming a unipolar prosthesis. The proprietary designof the mold will insure the proper sequence of filling ofcement/antibiotic mixture.

6 After time for maturation of the cement,the mold can be opened, and one will have a near perfectly formedunipolar cement/antibiotic hip Spacer . Any alterations needed can beaccomplished with use of a low speed burr or additional cementwhere appropriate at the discretion of the recommend using existing orthopedic literature with regards tothe length of treatment for the patients particular infection. We wouldrecommend protected weightbearing in the postoperative period, andthe use of an hip abduction orthosis set at a range of motiondetermined by the surgeon at the time of feel that having this functional Spacer will offer the followingadvantages:1.

7 Facilitate future conversion to hip replacement by keeping the softtissues out to Allow physiologic flexion and extension of the hip and allow forsome hip musculature function, which would normally beelectrically silent during this six to eight week period of The patients will have less pain and better function. This willextrapolate into less narcotics in the post operative period,decreased hospital stay, and less cost for the initial Also, importantly the subsequent surgical procedure is moreeasily performed, as the surgeon does not have to spend aninordinate amount of time trying to get the femur out to portion of the conversion surgery always involves atremendous amount of soft tissue dissection as well as blood will save time and money.

8 In revision surgery any time savedis welcomed, and any cost savings is a real Morton Bertram III, Total Joint CentersNaples, FloridaSurgical technique for the Bertram Hip SpacerThis technique is available on the Internet at If not a registered user, the registrationprocess takes less than 60 seconds and is very simple. After loggingin, click on Techniques, then the hip portion of the skeleton, and Bertram Hip Spacer . Or go to the Companies portion of the site,and click on Bertram Enterprises, then Bertram Hip Spacer .1. After removal of the infected implant further preparation of thefemoral canal as well as acetabular sizing can be accomplished in anumber of ways.

9 Any bipolar system could be used to determine thesize of the acetabulum. In this system you have three options forsizing of the acetabulum:Size 3-52 mm Head (with a 13 mm distal stem, 35mm necklength,140mm length) 3 batches of cementSize 5-56 mm Head (with a 15 mm distal stem, 40 mm necklength,160mm length) 4 batches of cementSize 7-60 mm Head (with a 17 mm distal stem, 45 mm necklength,180mm length) 5 batches of cementAll implants have 127 degree neck shaft angle, to assist in offset, withimproved clearance and The femur can be prepared with any number of cylindricalreamers. We recommend overreaming by 1 mm based on the size ofyour implant chosen, and to prepare the femur for the length asshown above.

10 Osteonics "Restoration" reamers are ideally suited forthe preparation of the femoral canal. Acetabular preparation is withbasket reamers keeping in mind the sizes above. Exact sizing is Depending upon the system that you choose you can assemble atrial prosthesis to check your leg lengths and stability. You need tosimply assemble a combination of acetabular sizes neck lengths anddistal stem combinations given above. If you find that your patientfalls in between the sizes is given above, you can modify the productof the mold to meet your needs. This can be done with a high-speedburr to down size the Spacer , or you could use additional cement toadd to a smaller Spacer where necessary to fit your Once you have determined the appropriate sized Spacer for yourpatient you are ready to build it on the back table.