Step by step guide Planning total hip arthroplasty

Step by step guide: Planning total hip arthroplasty Lecture AO Recon Course—Principles of Total Hip and Knee Arthroplasty

Learning objectives • Describe the key steps of planning a THA • Explain the templating process and its relevance with regards to these key steps • Recognize the benefit of a checklist provided in the Skills Lab booklet 2

Preoperative planning—introduction • Detailed clinical and x-ray examination • To prevent: • Component malposition • Increased rate of aseptic loosening • Increased rate of dislocation • Bad functional results 3

Preoperative planning—goals • To accurately implant the components: • Type • Size • Positioning • To avoid problems: • Complications • Patient dissatisfaction 4

Restoration of the center of rotation ] GMV[ccm • Joint reaction forces BW [N] • Muscle lever arm BW-LA[m] • Range of motion • Impingement • Instability 5 Preininger et al. (Man Ther 2011; Oct; 16(5): 447 -451

Restoration of the center of rotation ] GMV[ccm • Joint reaction forces • Range of motion • Impingement • Instability Preininger et al. (Man Ther 2011; Oct; 16(5): 447 -451 6 BW [N] • Muscle lever arm BW-LA[m]

Planning total hip arthroplasty 7

Radiographic evaluation • AP: • 10– 15° internal rotation (compensates for femoral neck anteversion offset) • True lateral: • Osteophytes 8

Radiographic evaluation • AP: • 10– 15° internal rotation (compensates for femoral neck anteversion offset) • True lateral: • Osteophytes Scheerlinck (Acta Orthop. Belg. , 2010, 76, 432– 442) 9

Radiographic evaluation • AP: • 10– 15° internal rotation (compensates for femoral neck anteversion offset) • True lateral: • Osteophytes 10

Step 1: Magnification External markers Davila et al (Skeletal Radiol. 2006 Jun; 35(6): 390– 393) Bono (J Bone Joint Surg Am. 2004; 86 -A Suppl 2: 118– 22) 12

Step 2: Identify x-ray landmarks • Tear drop—inferomedial acetabulum • Placement of inferior edge of the cup Gonzales et al (JOA 2005) 13

Step 2: Identify x-ray landmarks • Tear drop—inferomedial acetabulum • Placement of inferior edge of the cup • Ilioischial line Gonzales et al (JOA 2005) 14

Step 2: Identify x-ray landmarks • Tear drop—inferomedial acetabulum • Placement of inferior edge of the cup • Ilioischial line • Superior acetabular edge Gonzales et al (JOA 2005) 15

Step 2: Identify x-ray landmarks • Femoral shaft • Greater trochanter • Lesser trochanter Scheerlinck (Acta Orthop. Belg. , 2010; 76: 432– 442) 16

Step 2: Identify x-ray landmarks • Femoral shaft • Greater trochanter • Lesser trochanter • Quality control: Foramen obturatum, distance between symphysis and sacrococcygeal joint women: 32 mm (range: 8– 50 mm); men: 47 mm (range: 15– 72 mm) Scheerlinck (Acta Orthop. Belg. , 2010, 76, 432– 442) 17

Step 3: Assess leg length • Clinical examination • Interteardrop line • Keep in mind causes of leg-length differences distal to the hip (eg, tibial trauma) 18

Step 4: Identify areas of deformity • Excessive version • Dysplasia • Retained hardware • Previous surgery (eg, osteotomy) • Template the contralateral side 19

Step 5: Template the acetabulum • Define the center of rotation (COR) • Inferior edge at the tear drop • Touch the ilioischial line • 45°of inclination • Define implant size Mabry T, in Surgery of the Hip, Ed. 2013 20

Step 6: Template the femur • Assess offset 21

Step 6: Template the femur • Assess offset • Verify leg length 22

Step 6: Template the femur • Assess offset Preliminary neck cut Trochanteric fossa • Verify leg length Greater trochanter • Define the femoral osteotomy @ Lesser trochanter 23

Step 6: Template the femur • • 24 Assess offset Verify leg length Define the femoral osteotomy Assess the configuration of the meta- and diaphysis

Take-home messages Planning helps to: • Note osseous deformities and landmarks • Determine the implant size • Correctly restore biomechanics of the joint 25

Take-home messages Planning helps to: • Note osseous deformities and landmarks • Determine the implant size • Correctly restore biomechanics of the joint Rehearse the procedure 26

Step by step guide: Planning total hip arthroplasty Lecture