Introduction Types of fixation cement fixation polymethylmethacrylate (PMMA) biologic fixation (cementless fixation) bone ingrowth login to view 1 more bullet bone ongrowth login to view 1 more bullet collared femoral stem helps transfer stress to calcar, reduce early subsidence, and control insertion depth used in both cemented and cementless fixation History cemented fixation first described by Gluck in 1891 Charnley popularized technique in 1950s login to view 1 more bullet failures in 1980s thought to be due to "cement disease" login to view 1 more bullet cementless fixation used throughout 1900s, with varying results in 1983, FDA approved Anatomic Medullary Locking (AML) implant login to view 1 more bullet proximally coated stems designed shortly thereafter due to concerns of thigh pain and osteolysis Prevalence of fixation technique increasing trend towards cementless fixation 93% of THA in United States in 2012 were cementless Templating can help achieve proper restoration of biomechanics and avoid complications standard radiograph with a known magnification and calibration marker is used goal is to optimize limb length and femoral offset Indications General indications: Debilitating pain with severe osteoarthritis affecting activities of daily living Failed conservative measures Hip fracture in native hip Avascular necrosis Cemented vs uncemented Dorr classification attempts to guide indications for cemented or uncemented femoral component fixation. Ratio is calculated as canal diameter 10 cm distal to midportion of lesser trochanter divided by inner canal diameter at midportion of lesser trochanter Dorr Classification Ratio Characteristics Suggested Femoral Component Fixation Type A < 0.5 Cortices seen on both AP and lateral XR Uncemented Type B 0.5 to 0.75 Thinning of posterior cortex on lateral XR Uncemented type C >0.75 Thinning of cortices on both views Cemented Acetabular cup fixation porous-coated cementless (preferred) porous-coated hemispheric cementless cemented fixation login to view 2 more bullets Femoral stem fixation both cemented and cementless techniques are acceptable in THA cementless indications login to view 2 more bullets types of cemented femoral stems login to view 33 more bullets types of cementless femoral stems login to view 12 more bullets Stem Modularity login to view 4 more bullets Cement Fixation Mechanism acts as grout by producing interlocking fit between surfaces Indications femoral component elderly patients login to view 1 more bullet irradiated bone login to view 1 more bullet "stovepipe femur" login to view 2 more bullets acetabular component controversial login to view 2 more bullets Technique cementing techniques have evolved with time 1st generation login to view 3 more bullets 2nd generation login to view 4 more bullets 3rd generation login to view 4 more bullets cement fixation optimized by limited porosity of cement login to view 2 more bullets pressurization login to view 1 more bullet cement mantle > 2mm login to view 1 more bullet stiff femoral stem login to view 1 more bullet stem centralization login to view 1 more bullet clean/dry bone login to view 1 more bullet smooth femoral stem login to view 1 more bullet absence of mantle defects login to view 2 more bullets proper component positioning within femoral canal login to view 1 more bullet Radiographic analysis Barrack and Harris grading system grade A login to view 2 more bullets grade B login to view 1 more bullet grade C login to view 1 more bullet grade D login to view 1 more bullet Biologic Fixation Mechanism 2 different types ingrowth login to view 1 more bullet ongrowth login to view 1 more bullet Indications femoral component younger patients older patients with good bone stock revision total hip arthroplasty login to view 1 more bullet acetabular component all situations except login to view 2 more bullets Technique methods press fit technique login to view 2 more bullets line-to-line technique login to view 2 more bullets biologic fixation is optimized with pore size 50-300um login to view 1 more bullet porosity of 40-80% login to view 2 more bullets gaps < 50um login to view 2 more bullets micromotion < 150um login to view 2 more bullets maximal contact with cortical bone login to view 2 more bullets viable bone login to view 1 more bullet types of coating porous-coated metallic surfaces login to view 7 more bullets grit blasted metallic surface login to view 4 more bullets hydroxyapatite (HA) login to view 10 more bullets Radiographic analysis signs of a well-fixed cementless femoral component spot-welds login to view 1 more bullet absence of radiolucent lines around porous portion of femoral stem proximal stress shielding in extensively-coated stems absence of stem subsidence on serial radiographs signs of a well-fixed cementless acetabular component lack of migration on serial radiographs lack of progressive radiolucent lines intact acetabular screws Complications of Implant Fixation Aseptic loosening causes poor initial fixation mechanical loss of fixation over time particle-induced osteolysis clinical presentation acetabular loosening login to view 1 more bullet femoral loosening login to view 2 more bullets evaluation sequential radiographs bone scan treatment revision of loose components Stress shielding definition proximal femoral bone loss in the setting of a well-fixed stem risk factors stiff femoral stem login to view 3 more bullets large diameter stem login to view 1 more bullet extensively porous coated stem greater preoperative osteopenia clinical implications clinical implications of proximal stress shielding unknown treatment no specific treatment is necessary Intraoperative fracture risk factors use of press fit technique recent studies suggest collared femoral stems demonstrate a protective effect against early periprosthetic fractures treatment acetabular fracture login to view 4 more bullets femur fracture login to view 6 more bullets