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The High Hip Center
NIKOLAOS ATH. CHRISTODOULOU, ORTHOPEDIC SURGEON MD PhD
Orthopedics or Orthopaedics ? The unknown ancient Greek etymology (orthos & pedion)
NEW THREADED ACETABULAR AND DENTAL TITANIUM IMPLANTS !
Threaded titanium implants with an osseointegrated surface in hip arthroplasties similar to the best dental implants in the jawbone !
In the past implants of chromium, cobalt, Vitale or ceramic have been tested with "Press Fit" or threaded fastening technique in the jawbone in order to replace worn teeth.
From 1970 to date only screw dental titanium implants whith an osseointegrated surface have established because they showed the best permanent stable fixation and have a larger contact surface with the bone compared to other materials of the same diameter.
So in the hip joint also new generation threaded acetabular titanium implants Zweymuller type with thin fins (lamelae) and roughened and osseointegradable surface showed excellent permanent results as in our long series of patients at the acetabulum site which is similar in formation to that of the remaining area of the jawbone after the removal of a damaged tooth.
In hip arthroplasties in contrast with the successful threaded teeth implants they have been slow to be established internationally because many orthopedic hip surgeons thought that they are not so good because they had similar shape with the unsuccessful old Mittelmeiyer type, Link, PCA or other anelastic and with smooth surface screwed hip cups used mainly in the 1980s which were accompanied by large percentages of mechanical loosening. These old cups had showed only primary mechanical stability but not permanent biological fixation and no periprothetic new bone formation.
The difference is that the new generation titanium threaded dental or Zweymuller and similar type implants are no so rigid and they have roughened titanium surface and thin fins (lamaele) with excellent osseontigration possibility and permanent biological fixation.
Thanks to the famous professor of Vienna Zweymuller many orthopedic surgeons including myself became aware of the considerable capabilities of these new threaded titanium acetabular implants. The Zweymuller cup with titanium roughened and osseointegrated surface has sharp-cutting thread blades able for improve the penetration of the thread teeth even into an subchondral sclerotic zone.
So, after several years of scientific erroneous assessment and in continuance to the excellent Zweymuller cup results, many other similar threaded titanium cups with osseointegrated surface are now introduced in the market ( Smith & Nephew, Zimmer, Implant Cast, Lima, Permedica, Aesculap and many others ) and make unnecessary the problematic - mainly in the revision hip arthroplasty surgery - use of acrylic cement or screws.
The results in hip arthroplasties are excellent and perfectly comparable to those of highly successful dental screw implants in both simple cases of hip osteoarthritis and in cases of osteoarthritis secondary to congenital dysplasia, low congenital hip dislocation or other deseases.
Especially in cases in which the threaded titanium acetabular implant is combined with rectagular antirotational stem with osseontegrated also surface the result is almost perfect.
There are indications that the coveraged with new periprothetic bone threaded titanium implant surfaces without necrotic area between implant and bone - as in cases in which acrylic cement is used - reduces the risk of infections. Around mandibular threaded titanium implants although the mouth is not a sterile area rarely are caused infections.
In our Clinic we place these implants using the new so-called ALMIS (Antero-Lateral Minimally Invasive Surgery) tecnique. This modified our technique has established in the Master Techniques in Orthopaedic Surgery as "Mayo Limited - Minimal Anterior” - USA.
The usually very laborious and complicated revision surgery to remove broken screws from the iliac bone or acrylic cement in cases of a hip arthroplasty loosening is avoided.
The absence of screws or acrylic cement in threaded titanium acetabular prostheses makes easy the review process in very rare cases of loosening and leaves enough healthy periprosthetic bone intact or not infected to place a new one threaded titanium implant.
Threaded titanium implants with osseointegrated surface in the jawbone and hip acetabulum seem to be the most ideal and permanent solution to these difficult and too loaded damaged bone areas ! This is the future..
https://en.wikipedia.org/wiki/Osseointegration
https://www.youtube.com/watch?v=-p7LDOjrBaI
https://www.youtube.com/watch?v=ejcJ-CVMkiI
THREADED ACETABULAR IMPLANT WITH EXCELLENT OSSEOINTEGRATION (R-SIDE), USUAL IMPLANT (L-SIDE)
THE HIGH HIP CENTER
The High Hip Center Technique in Osteoarthritic Congenital Dislocated Hips
By Drs Nikolaos Christodoulou & Konstantinos Dialetis
[Remarks & Observations]
“ New functional hip center adaptable to all anatomical deformities of each case with minimal intervention in soft tissue and bones using special new osseointegrated implants ”
The surgical correction of a dysplasic osteorthritic hip is a challenge even for an expert orthopaedic hip surgeon. It requires careful study of all anatomic abnormalities which accompany the untreated congenital dislocated hip in adults and careful preoperative planning, especially in cases of previously made femoral or acetabular osteotomies, in addition to radiographic study, 3D CT scanning and measurement of the diameters of the iliac bone near the true acetabulum or at the region between the true and false acetabulum.In this way we can conclude where there is sufficient available bone stock for stable fixation of the acetabular component of a total hip arthroplasty.The abnormalities of dysplasic or congenital dislocated hips have been described enough and are categorised by many authors (Hartofilakidis et al., JBJS-A, 1996, Crowe et al., JBJS-A, 1979, Eftekhar, 1978., Mendes et al., Orthopedics, 1996). The last one uses an algorithm of surgical treatment of these hips which takes into consideration not only the osseous periacetabular abnormalities but all secondary myosceletal changes which must be accentuated and which are very different in every patient.A personal observation of the second author of this article (Dialetis K.) is that the difficulty of lowering a congenital dislocated hip depends also on the preoperative position of the trochanteric region of the femur in correlation with the position of the true acetabulum. In some cases of dysplasic or low dislocated hips, the tip of greater trochanter is higher than in some cases of high dislocated hips depending on the varus or valgus deformity of the femoral neck as in cases of previous varus or valgus femoral osteotomies. The difficulties of the lowering of a congenital dislocated hip depends also on the preoperative permanent or flexible lateral tilting of the pelvis and the lumbar spine, stiff or flexible hyperlordosis and also on the preoperative inequality. Surgical correction (> 3cm) of a stiff clinical inequality including stiff chronic lateral tilting of the pelvis and the lumbar spine may be unacceptable by the patient. This may be obvious preoperatively by elevating the shoe of the short leg of the patient and control the acceptance of this correction.Many muscular groups chronic contracture must be corrected or be taken in mind before and during surgery. Usually chronically contracted muscles as hamstrings, hip adductors, quatriceps, Iliopsoas,Tensor Fascia Lata, gluteous maximus, quatratus lumborum are very difficult to be all corrected with the true acetabulum reconstruction in congenital dislocated hip patients.(Haddad et all, Instr Course Lect, Cl. Orthop.,49:23-39;2000).In dysplasic hips (Hartofilakidis classification), there is not usually problem to fix the acetabulum component at normal or near to approximate hip center according to Ranawat using new acetabular components with osseointegrated metal backs and augmented surfaces.In low dislocated hips according to Hartofilakidis classification (JBJS-A., 1996) there is usually a serious problem of acetabulum roof insufficiency.In high dislocated hips (Hartofilakidis classification) usually every case is very different from any other and the difficulties to lower the hip is depended on many factors such as the different sufficient bone stock region to fix the acetabulum and the probability of neuromuscular or muscles injury by different soft tissue injuries and traction during the operation.In our opinion the preferable acetabular component position for each patient with high hip dislocation must be founded by studying the best relation between possible periprothetic injuries, possible complications and stable acetabulum fixation. Strong traction and limp elongation more than 4 cm during the attempt to reconstruct the hip center near the true acetabulum in all cases may have a result of sciatic or femoral nerve paresis (Eggli et all, JBJS Br, 1999., Jaroszynski et all, Clin Orthop, Inst Course Lect.:50:307-316., 2001., Argenson et all, Clin Orthop, 2007).Cement augmentation, bone grafts acetabular augmentation, small acetabular components, medialization and cotyloplasties, or reinforced rings for reconstruction of the hip near the normal hip center have presented many complications as elevated rates of mechanical loosening. (Antti Eskelinen et al.,JBJS (Am), 88:80-91.2006., Erdemli et al., Journal Arthroplasty, 20.1021-1028. 2000.,, Andrew et al., JBJS.,79:159-68.,1997., Stans et al., Clin Orthop Relat Res., 348149-57.,1998., Becker et al., Acta Orthop Scand. 70(5):430-4.,1999., Hendrich et al., JBJS(Am) 88:387-394.2006., DiFazio et al., JBJS(Am),84-A(2):204-7. 2002., Chougle et al., JBJS (Br)Vol 87-B / 1, 16-20.2005., Kobayashi et al., JBJS(Am) 85:615-621.,2003).High hip center ,as a valuable alternative solution, has been proposed by some authors presenting some benefits such as no use of bone structural grafts, low number of neurovascular injuries, adequate remaining bone stock for revision, easy restoration of the limb length without osteotomies. By using longer necks/heads length adequate and safe leg lengthening is succeeded in combination with normal strength and level of abtuctors and diminution of hip impingement. In the high hip center technique also no complementary femoral osteotomies are needed resulting to a short duration anesthesia and surgery with minimal blood loss in correlation with few consequent perioperative complications (Justy & Freiberg., Semin Arthroplasty, 1995., Sutherland et al., J Arthroplasty, 11(1):91-98, 1996., Tanzer M., Orthop Clin North Am. 1998., Ito et al., JBJS Am. 2003., Perka et Al., JBJS Am. 2004., Kobayashi et all, JBJS Am, 2004., Russotti & Harris, JBJS Am., 1992 ., Delp et al Clin. Orthop., 328: 137-146, 1996., Dearton & Harris, JBJS Am. 1999 ., Mackenzie et al., JBJS (Am) 78:55-61., 1996 ., Bozic et al, Clin Orthop Relat Res, 420:101-5. 2004., Fousek et al.,Acta Chir Orthop Traum. Cech. 2007).In some experimental studies (Johnston et al., JBJS Am. 1979- Mathematical approach., Doehring et al., Athroplasty, 1996) without using congenital dislocated hip models it is mentioned that it is not biomechanical accepted to transfer the hip center high or lateral of the true acetabulum. This is very logical for primary osteoarthritic hips but in cases of chronically displaced hip center in a very high hip position in which the hip was working for many decades in this position it is normal to transfer it in a very low hip position? There is not any biomechanical study which can answer to this question until now.There are also some clinical works in which it seems that the position of the acetabular component in a high hip position especially if it was accompanied by lateral cup placemant has been resulted to elevated rates of loosening (Pagnano et al., JBJS. 1996., Johnston et al, J. Bone Joint Surg. Am. 61:639-652, 1979).But these results are unreliable because most of the different kinds of the acetabular componens used in these works have been withdrawed recently by authors and most of these prostheses are not used actually because of elevated rates of loosening even in the near to the true acetabulum position.In these no prospective studies, no control groups with the same characteristics of patients are usually used, different acetabular implants and methods are used in very different patients containing in the same studied group young and older patients, obese and osteoporotic, difficult or easy surgically corrected cases, or cases with flexible and stiff pelvis and spine tilting, as also cases of unilateral and bilateral hip dislocations.Is it normal to transfer the hip center rotation from a very high position to a very low position at the region of the true acetabulum in congenital dislocated hip cases in adults? This is logical only if all chronic accompanied myoskeletal changes of the patient are possible to be corrected simultaneously with the transfer of the hip center as in cases of congenital dislocation of the hip in a child aged some months. In high congenital dislocated hip cases in adults it is very difficult and in some cases dangerous to correct all these accompanied myoskeletal changes. In cases of unilateral congenital hip dislocation inequality more than 3 cm accompanied from many stiff changes of the pelvis and the lumbar spine may have the result of apparent elongation of the leg unacceptable by the patient. Some authors accompany the reconstruction near the true acetabulum with femoral osteotomies in order to decrease the muscles traction and the elongation of the leg but the femoral osteotomies increase the anesthesia and surgery duration, the blood loss and the accompanied perioperative complications. There is not any work until now which can determine where is the perfect hip center rotation for a congenital dislocated hip patient with leg inequality more than 3 cm and chronic myoskeletal changes.In some experimental works (. Delp et al.,Clin. Orthop., 1996, Doehring et al., J. Arthroplasty,1996., Vasavada et al., Cl. Ortop., 1994)it is emphasized that it is possible to transfer the hip center to a higher than normal position without elevation of the greater trochanter using elongated arthroplasty necks or heads, with that superior relocation not having altered significantly the total joint forces or its components. When relocation is necessary, care should be taken to minimize the lateral displacement (Doehring et al., Athroplasty, 1996.The results of these studies suggest that superior positioning of the hip center, without lateral placement, does not have major adverse effects on abduction moment arms or force generating capacities when the neck length is appropriately increased.A computer model was developed to estimate the maximum isometric moment generating capacity of the hip muscles under two conditions. In the compensated condition, the hip center was displaced, but the muscles were restored to their original lengths and orientations by altering proximal femoral geometry. In the uncompensated condition, femoral geometry remained constant; thus, muscle lengths and orientations changed with displacement of the hip center. The results demonstrate that compensating for changes in muscle length can be important in terms of preserving the moment generating capacity of the muscles when the hip center is displaced superiorly and medially (Anita N. Vasavada et al., Cl. Orthop.1994).Fig.: 2 Εlongation of the arthroplasty femoral neck or head in a high hip center technique increase the abductor moment arm (H), and the traction and length of abtuctors without important increase of the weight bearing moment arm (medialisation).In the Russotti et al.,JBJS-A., 1991 study the placement of the acetabular component at a more proximal position is recommended in difficult acetabular reconstructions, but not at lateral position, if this is necessitated by the available bone stock, so that most of the component can be supported by host bone. In the work of Dearton et al., JBJS-A., 1999 also, it is mentioned that the use of a high hip center did not adversely affect function of the abductor muscles, and the mean limb-length discrepancy is reduced by the femoral reconstruction.The lack of an association between the height of the hip center and loosening of the acetabular component suggests that only lateral, and not proximal or distal, cup displacement is a major cause of cup loosening.Proximal placement of the hip center facilitates contact between intact, viable host bone and the acetabular implant, especially in the cases of the low hip dislocations, thereby reducing the need for structrural bone grafts, and increasing the changes for stable bone ingrowth (Bozic et al, Clin Orthop,,2004).By restoring the leg lengthening by using the tension limits of the abtuctors muscles and suitable neck lengths in the stems, there is not need of additional bone grafts or femoral osteotomies.Although few previously mentioned biomechanical studies have shown that supero-lateral placement of the hip center may lead to increased moments and forces across the joint leading to potentially higher rates of loosening, the use of a bicon osseointegrated Zweymuller threaded cup (Zweymuller et al., Cl. Orthop., 463, 228-137, 2007) - in combination with a straight cementless stem with a double taper- at a higher than normal hip position in patients with congenital hip disease in our series of patients, 106 congenital hip disease cases, 30 high hip centers, - 39.7mm higher from interteardrop line ( 33.1 - 60 mm ), HC > 15mm distance from AFHC, (approximate femoral head center), 16 out of Ranawat Triangle & > 35mm from interteardrop line and 14 in the Ranawat Triangle, 7 >35mm & 7 < 35mm from interteardrop line) does not seem to present higher rates of loosening than those which have occurred in the near the true acetabulum placed cups or elevated rates of polyethylene wear in a follow up of 14 years even in cases with not fully cup covering by acetabular roof bone. More details of our High Hip Center technique, material and methods, as also clinical and radiological results you will find in the Power Point entitled “Ηigh Hip Center” linked to wwwwww.christodoulou-n.blogspot site. There was not found statistically significant difference of polyethylene wear between high and low hip position cases by using the CT wear measurement software Roman Program.
The surgical correction of a dysplasic osteorthritic hip is a challenge even for an expert orthopaedic hip surgeon. It requires careful study of all anatomic abnormalities which accompany the untreated congenital dislocated hip in adults and careful preoperative planning, especially in cases of previously made femoral or acetabular osteotomies, in addition to radiographic study, 3D CT scanning and measurement of the diameters of the iliac bone near the true acetabulum or at the region between the true and false acetabulum.In this way we can conclude where there is sufficient available bone stock for stable fixation of the acetabular component of a total hip arthroplasty.The abnormalities of dysplasic or congenital dislocated hips have been described enough and are categorised by many authors (Hartofilakidis et al., JBJS-A, 1996, Crowe et al., JBJS-A, 1979, Eftekhar, 1978., Mendes et al., Orthopedics, 1996). The last one uses an algorithm of surgical treatment of these hips which takes into consideration not only the osseous periacetabular abnormalities but all secondary myosceletal changes which must be accentuated and which are very different in every patient.A personal observation of the second author of this article (Dialetis K.) is that the difficulty of lowering a congenital dislocated hip depends also on the preoperative position of the trochanteric region of the femur in correlation with the position of the true acetabulum. In some cases of dysplasic or low dislocated hips, the tip of greater trochanter is higher than in some cases of high dislocated hips depending on the varus or valgus deformity of the femoral neck as in cases of previous varus or valgus femoral osteotomies. The difficulties of the lowering of a congenital dislocated hip depends also on the preoperative permanent or flexible lateral tilting of the pelvis and the lumbar spine, stiff or flexible hyperlordosis and also on the preoperative inequality. Surgical correction (> 3cm) of a stiff clinical inequality including stiff chronic lateral tilting of the pelvis and the lumbar spine may be unacceptable by the patient. This may be obvious preoperatively by elevating the shoe of the short leg of the patient and control the acceptance of this correction.Many muscular groups chronic contracture must be corrected or be taken in mind before and during surgery. Usually chronically contracted muscles as hamstrings, hip adductors, quatriceps, Iliopsoas,Tensor Fascia Lata, gluteous maximus, quatratus lumborum are very difficult to be all corrected with the true acetabulum reconstruction in congenital dislocated hip patients.(Haddad et all, Instr Course Lect, Cl. Orthop.,49:23-39;2000).In dysplasic hips (Hartofilakidis classification), there is not usually problem to fix the acetabulum component at normal or near to approximate hip center according to Ranawat using new acetabular components with osseointegrated metal backs and augmented surfaces.In low dislocated hips according to Hartofilakidis classification (JBJS-A., 1996) there is usually a serious problem of acetabulum roof insufficiency.In high dislocated hips (Hartofilakidis classification) usually every case is very different from any other and the difficulties to lower the hip is depended on many factors such as the different sufficient bone stock region to fix the acetabulum and the probability of neuromuscular or muscles injury by different soft tissue injuries and traction during the operation.In our opinion the preferable acetabular component position for each patient with high hip dislocation must be founded by studying the best relation between possible periprothetic injuries, possible complications and stable acetabulum fixation. Strong traction and limp elongation more than 4 cm during the attempt to reconstruct the hip center near the true acetabulum in all cases may have a result of sciatic or femoral nerve paresis (Eggli et all, JBJS Br, 1999., Jaroszynski et all, Clin Orthop, Inst Course Lect.:50:307-316., 2001., Argenson et all, Clin Orthop, 2007).Cement augmentation, bone grafts acetabular augmentation, small acetabular components, medialization and cotyloplasties, or reinforced rings for reconstruction of the hip near the normal hip center have presented many complications as elevated rates of mechanical loosening. (Antti Eskelinen et al.,JBJS (Am), 88:80-91.2006., Erdemli et al., Journal Arthroplasty, 20.1021-1028. 2000.,, Andrew et al., JBJS.,79:159-68.,1997., Stans et al., Clin Orthop Relat Res., 348149-57.,1998., Becker et al., Acta Orthop Scand. 70(5):430-4.,1999., Hendrich et al., JBJS(Am) 88:387-394.2006., DiFazio et al., JBJS(Am),84-A(2):204-7. 2002., Chougle et al., JBJS (Br)Vol 87-B / 1, 16-20.2005., Kobayashi et al., JBJS(Am) 85:615-621.,2003).High hip center ,as a valuable alternative solution, has been proposed by some authors presenting some benefits such as no use of bone structural grafts, low number of neurovascular injuries, adequate remaining bone stock for revision, easy restoration of the limb length without osteotomies. By using longer necks/heads length adequate and safe leg lengthening is succeeded in combination with normal strength and level of abtuctors and diminution of hip impingement. In the high hip center technique also no complementary femoral osteotomies are needed resulting to a short duration anesthesia and surgery with minimal blood loss in correlation with few consequent perioperative complications (Justy & Freiberg., Semin Arthroplasty, 1995., Sutherland et al., J Arthroplasty, 11(1):91-98, 1996., Tanzer M., Orthop Clin North Am. 1998., Ito et al., JBJS Am. 2003., Perka et Al., JBJS Am. 2004., Kobayashi et all, JBJS Am, 2004., Russotti & Harris, JBJS Am., 1992 ., Delp et al Clin. Orthop., 328: 137-146, 1996., Dearton & Harris, JBJS Am. 1999 ., Mackenzie et al., JBJS (Am) 78:55-61., 1996 ., Bozic et al, Clin Orthop Relat Res, 420:101-5. 2004., Fousek et al.,Acta Chir Orthop Traum. Cech. 2007).In some experimental studies (Johnston et al., JBJS Am. 1979- Mathematical approach., Doehring et al., Athroplasty, 1996) without using congenital dislocated hip models it is mentioned that it is not biomechanical accepted to transfer the hip center high or lateral of the true acetabulum. This is very logical for primary osteoarthritic hips but in cases of chronically displaced hip center in a very high hip position in which the hip was working for many decades in this position it is normal to transfer it in a very low hip position? There is not any biomechanical study which can answer to this question until now.There are also some clinical works in which it seems that the position of the acetabular component in a high hip position especially if it was accompanied by lateral cup placemant has been resulted to elevated rates of loosening (Pagnano et al., JBJS. 1996., Johnston et al, J. Bone Joint Surg. Am. 61:639-652, 1979).But these results are unreliable because most of the different kinds of the acetabular componens used in these works have been withdrawed recently by authors and most of these prostheses are not used actually because of elevated rates of loosening even in the near to the true acetabulum position.In these no prospective studies, no control groups with the same characteristics of patients are usually used, different acetabular implants and methods are used in very different patients containing in the same studied group young and older patients, obese and osteoporotic, difficult or easy surgically corrected cases, or cases with flexible and stiff pelvis and spine tilting, as also cases of unilateral and bilateral hip dislocations.Is it normal to transfer the hip center rotation from a very high position to a very low position at the region of the true acetabulum in congenital dislocated hip cases in adults? This is logical only if all chronic accompanied myoskeletal changes of the patient are possible to be corrected simultaneously with the transfer of the hip center as in cases of congenital dislocation of the hip in a child aged some months. In high congenital dislocated hip cases in adults it is very difficult and in some cases dangerous to correct all these accompanied myoskeletal changes. In cases of unilateral congenital hip dislocation inequality more than 3 cm accompanied from many stiff changes of the pelvis and the lumbar spine may have the result of apparent elongation of the leg unacceptable by the patient. Some authors accompany the reconstruction near the true acetabulum with femoral osteotomies in order to decrease the muscles traction and the elongation of the leg but the femoral osteotomies increase the anesthesia and surgery duration, the blood loss and the accompanied perioperative complications. There is not any work until now which can determine where is the perfect hip center rotation for a congenital dislocated hip patient with leg inequality more than 3 cm and chronic myoskeletal changes.In some experimental works (. Delp et al.,Clin. Orthop., 1996, Doehring et al., J. Arthroplasty,1996., Vasavada et al., Cl. Ortop., 1994)it is emphasized that it is possible to transfer the hip center to a higher than normal position without elevation of the greater trochanter using elongated arthroplasty necks or heads, with that superior relocation not having altered significantly the total joint forces or its components. When relocation is necessary, care should be taken to minimize the lateral displacement (Doehring et al., Athroplasty, 1996.The results of these studies suggest that superior positioning of the hip center, without lateral placement, does not have major adverse effects on abduction moment arms or force generating capacities when the neck length is appropriately increased.A computer model was developed to estimate the maximum isometric moment generating capacity of the hip muscles under two conditions. In the compensated condition, the hip center was displaced, but the muscles were restored to their original lengths and orientations by altering proximal femoral geometry. In the uncompensated condition, femoral geometry remained constant; thus, muscle lengths and orientations changed with displacement of the hip center. The results demonstrate that compensating for changes in muscle length can be important in terms of preserving the moment generating capacity of the muscles when the hip center is displaced superiorly and medially (Anita N. Vasavada et al., Cl. Orthop.1994).Fig.: 2 Εlongation of the arthroplasty femoral neck or head in a high hip center technique increase the abductor moment arm (H), and the traction and length of abtuctors without important increase of the weight bearing moment arm (medialisation).In the Russotti et al.,JBJS-A., 1991 study the placement of the acetabular component at a more proximal position is recommended in difficult acetabular reconstructions, but not at lateral position, if this is necessitated by the available bone stock, so that most of the component can be supported by host bone. In the work of Dearton et al., JBJS-A., 1999 also, it is mentioned that the use of a high hip center did not adversely affect function of the abductor muscles, and the mean limb-length discrepancy is reduced by the femoral reconstruction.The lack of an association between the height of the hip center and loosening of the acetabular component suggests that only lateral, and not proximal or distal, cup displacement is a major cause of cup loosening.Proximal placement of the hip center facilitates contact between intact, viable host bone and the acetabular implant, especially in the cases of the low hip dislocations, thereby reducing the need for structrural bone grafts, and increasing the changes for stable bone ingrowth (Bozic et al, Clin Orthop,,2004).By restoring the leg lengthening by using the tension limits of the abtuctors muscles and suitable neck lengths in the stems, there is not need of additional bone grafts or femoral osteotomies.Although few previously mentioned biomechanical studies have shown that supero-lateral placement of the hip center may lead to increased moments and forces across the joint leading to potentially higher rates of loosening, the use of a bicon osseointegrated Zweymuller threaded cup (Zweymuller et al., Cl. Orthop., 463, 228-137, 2007) - in combination with a straight cementless stem with a double taper- at a higher than normal hip position in patients with congenital hip disease in our series of patients, 106 congenital hip disease cases, 30 high hip centers, - 39.7mm higher from interteardrop line ( 33.1 - 60 mm ), HC > 15mm distance from AFHC, (approximate femoral head center), 16 out of Ranawat Triangle & > 35mm from interteardrop line and 14 in the Ranawat Triangle, 7 >35mm & 7 < 35mm from interteardrop line) does not seem to present higher rates of loosening than those which have occurred in the near the true acetabulum placed cups or elevated rates of polyethylene wear in a follow up of 14 years even in cases with not fully cup covering by acetabular roof bone. More details of our High Hip Center technique, material and methods, as also clinical and radiological results you will find in the Power Point entitled “Ηigh Hip Center” linked to wwwwww.christodoulou-n.blogspot site. There was not found statistically significant difference of polyethylene wear between high and low hip position cases by using the CT wear measurement software Roman Program.
"HIGH HIP CENTER" TECHNIQUE !!!
IT IS ABNORMAL TO ELEVATE A PREVIOUS NORMAL HIP CENTER AT A HIGHER POSITION BUT IT IS ALSO ABNORMAL, DANGEROUS AND COMPLICATED - IN MANY CASES - TO TRANSFER A HIGH OR VERY HIGH CHRONIC CONGENITAL DISLOCATED HIP IN ADULTS (WITH A HIGH TROCHANTERIC REGION LEVEL, A BETTER BONE STOCK AT A HIGHER THAN NORMAL POSITION AND A STIFF CHRONIC LATERAL PELVIC OR LUMBAR SPINE DEFORMITY) TO A VERY LOW POSITION !!!
IN SUCH CASES, SIGNIFICANT ALSO MECHANICAL FORCES CAN BE APPLIED ON THE MUSCLES, NERVES AND IMPLANTS !!!
THE BEST FUNCTIONAL HIP CENTER FOR SOME OF THESE CASES IS A HIP CENTER LOCATED AT A HIGHER THAN A TRUE ACETABULUM POSITION ADAPTED TO THE BEST OSSEOUS HEALTHY SOLID REGION OF THE ILIAC BONE WITHOUT GRAFTING AND TO ALL CHRONIC PERI- PELVIC AND BODY DEFORMITIES USING A "HIGH HIP CENTER" TECHNIQUE WITH MINIMAL SOFT TISSUE AND BONES INJURIES IN COMBINATION WITH VERY SPECIAL OSSEOINTEGRATED IMPLANTS !!!
"HIGH HIP CENTER" TECHNIQUE ( 2013 ) !!!
CHRISTODOULOU ET AL, "HIGH HIP CENTER" PUBLICATIONS
1. HIGH HIP CENTER USING A BICONICAL THREADED ZWEYMULLER CUP IN OSTEOARTHRITIS SECONDARY TO CONGENITAL HIP DISEASE
N. CHRISTDOULOU, K. DIALETIS, ATH. CHRISTODOULOU,
CLINICAL ORTHOPAEDICS AND RELATED RESEARCH 2010. Full text here:
http://www.springerlink.com/content/r788082m68807123/fulltext.pdf
2. NON ANATOMICAL POSITIONING (HIGH HIP CENTER) OF ZWEYMULLER CUP IN OSTEOARTHRITIS SECONDARY TO CONGENITAL HIP DISEASES
K. DIALETIS, N. CHRISTODOULOU..., JBJS Volume 91-B 2009.
N. CHRISTDOULOU, K. DIALETIS, ATH. CHRISTODOULOU,
CLINICAL ORTHOPAEDICS AND RELATED RESEARCH 2010. Full text here:
http://www.springerlink.com/content/r788082m68807123/fulltext.pdf
2. NON ANATOMICAL POSITIONING (HIGH HIP CENTER) OF ZWEYMULLER CUP IN OSTEOARTHRITIS SECONDARY TO CONGENITAL HIP DISEASES
K. DIALETIS, N. CHRISTODOULOU..., JBJS Volume 91-B 2009.
LINKS - INSTRUCTIONAL COURSES BY N. CHRISTODOULOU MD, PhD - etc.
- Christodoulou. N
- [ANTERO]-LATERAL HIP APPROACH [A.L.M.I.S.]
- Citieffe/CH-N Trochanteric Fixator
- Minimally Invasive High Tibial Osteotomy
- Aseptic Loosening of THA - History
- Revision of TKA; Knee Extensor Mechanism Problems
- BIOMECHANICS OF THE ELBOW JOINT
- SURGICAL TREATMENT OF SPASTIC DEFORMITIES
- Dialetis. K
- Monika Music Greece
- MONIKA-MUSIC-GREECE
ZWEYMULLER HIP ARTHROPLASTY
ZWEYMULLER CUPS - EXCELLENT RESULTS
HIP ARTHROPLASTY CUP LOOSENING, EXCESSIVE PERI-ACETABULAR BONE LOSS
ZWEYMULLER LARGE SIZE OSSEOINTEGRATED CUP, STABLE FIXATION, NEW BONE FORMATION
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