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Re: Поиск источников информации?
послал Дедок Михаил 09 Июль 2008, 16:26
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Нашел в ортопедии wheeless
http://www.wheelessonline.com/ortho/paprosky_classification_of_acetabular_defects
Paprosky classification of Acetabular Defects
- based on the severity of bone loss and the ability to obtain cementless fixation for a given bone loss pattern;
- determines ability of remaining host bone to provide initial stability to a hemispherical cementless acetabular component until ingrowth occurs;
- classification based of integrity of:
- kohler line (ilioischial line): position of the implant relative to the Kohler line
- defined as a line connecting most lateral aspect of pelvic brim and most lateral aspect of obturator foramen on AP of pelvis;
- medial migration of the component relative to the Kohler line represents a deficiency of the anterior column;
- grade 1: medial aspect of the implant is lateral to the Kohler line;
- grade 2: there is migration to Kohler line or slight remodeling of iliopubic and ilioischial lines without a break in continuity;
- grade 3:
- migration medial to the line with Grade-3 migration;
- w/ extensive medial migration, consider angiography or CT w/ IV contrast and consider possible need for intrapelvic mobilization of vessels;
- osteolysis of teardrop:
- indicates bone loss from inferior and medial aspect of acetabulum, and inferior aspect of anterior column, lateral aspect of pubis, and medial wall;
- moderate osteolysis includes partial destruction of the structure with maintenance of the medial limb of the teardrop;
- severe involvement means complete obliteration of the teardrop;
- osteolysis of ischium:
- osteolysis is quantified by measuring distance from most inferior extent of lytic area to superior obturator line;
- indicates bone loss from the inferior aspect of the posterior column, including the posterior wall;
- acetabular component migration (superior migration of the hip center);
- superior migration is measured as the distance in millimeters (adjusted for magnification) relative to the superior obturator line;
- superior migration of the hip center represents bone loss in the acetabular dome involving the anterior and posterior columns;
- superior and medial migration indicates a greater involvement of the anterior column;
- superior and lateral migration indicates a greater involvement of the posterior column;
- Classifications:
- type I: rim is intact w/ no significant distortion of the rim
- acetabulum is hemispherical but there may be small focal areas of contained bone loss;
- anterior and posterior columns are intact;
- hemispherical cementless implant is almost completely supported by native bone and has full inherent stability;
- there is no migration of the component and no evidence of osteolysis in the ischium or teardrop;
- kohler line has not been violated (medialmost aspect of the component is lateral to the Kohler line);
- type II: distorted but intact rim with adequate remaining bone to support a hemispherical cementless implant;
- type IIa:
- anterior and posterior columns are supportive and the rim is intact
- bone loss is superior and medial;
- defect the hip center is migrated superior
- migration is less than 3 cm above the obturator line;
- failed component migrates into a cavitary defect medial to the thinned remaining superior rim;
- most defects are treated with particulate allograft because the defect is contained;
- type IIb:
- anterior and posterior columns will support an implant but there is a small superior rim defect which is not contained;
- remaining anterior and posterior rims and columns are supportive for an implant;
- superior rim is deficient for less than one third of the rim circumferene;
- migration is less than 3 cm above the obturator line directly superior or in combination with lateral migration;
- femoral head allograft may be appropriate but majority of segmental defects are not grafted;
- particulate graft is not an option with the Type IIB defects because there is no buttress to contain the graft;
- type IIc:
- there is medial wall defects and migration of the component medial to Kohler's line;
- rim of the acetabulum is intact and will support the component;
- reconstructions involve particulate graft placed medially;
- if the medial membrane is not a sufficient buttress for the particulate graft, then insert a wafer of femoral head into the defect;
- graft is then placed over the wafer butress;
- type III:
- acetabular rim is not adequate for initial stability of the component;
- allograft is necessary to help restore deficient host bone (inorder to restore stability of the implant);
- posterior column may require reconstruction;
- type IIIa:
- characterized by greater than 3 cm of superior migration of the femoral component cephalad to the superior obturator line,
moderate teardrop and ischial lysis, and an intact Kohler line;
- host bone is adequate for ingrowth but the acetabular rim is not entirely supporative;
- defects are associated with a nonsupportive superior dome
- anterior and posterior columns remain intact, but hemispherical shell will have less than 50 percent host bone contact;
- migration of implant is superior and lateral;
- surgical options include: figure 7 shape distal femoral allograft, use of a bilobed implant or a trabecular metal acetabular component with a superiorly
placed trabecular metal augment, or cup placement in the high hip center;
- type IIIb:
- there is less than 40% of host bone available for ingrowth;
- rim defect is greater than 1/2 circumference;
- failed component has migrated superior and medial;
- high risk of occult pelvic discontinuity (posterior column reconstruction necessary)
- massive allografting and reconstruction cages are typically needed;
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