Total hip arthroplasty planning

Abstract

Preoperative planning is mandatory to achieve the restoration of a correct and personalized biomechanics of the hip.The radiographic review is the first and fundamental step in the planning. Limb or pelvis malpositioning during the review results in mislead planning.Correct templating is possible using three different methods: acetate templating on digital X-ray, digital 2D templating on digital X-ray and 3D digital templating on CT scan.Time efficiency, costs, reproducibility and accuracy must be considered when comparing different templating methods. Based on these parameters, acetate templating should not be abandoned; digital templating allows a permanent record of planning and can be electronically viewed by different members of surgical team; 3D templating is intrinsically more accurate. There is no evidence in the few recently published studies that 3D templating impacts positively on clinical outcomes except in difficult cases.The transverse acetabular ligament (TAL) is a reliable intraoperative soft tissue reference to set cup position.Spine-hip relations in osteoarthritic patients undergoing hip joint replacement must be considered. Cite this article: EFORT Open Rev 2019;4:626-632. DOI: 10.1302/2058-5241.4.180075.

Keywords: digital templating; kinematic alignment; preoperative planning; spine–hip relation; total hip arthroplasty.

Fig. 1

(a) Example of bad X-ray for planning. Different femur rotation, wrong pelvic position, missing symmetry of foramen obturatum. (b) How the femoral rotation can affect offset evaluation.

Fig. 2

Example of incorrect X-ray image due to pelvic tilt following a lumbar arthrodesis.

Fig. 3

Same implant and patient, different X-ray angle leading to different evaluation of cup orientation. (a) incorrect beam angle: cup too vertical and anteverted position. (b) Correct beam angle: correct acetabular orientation.

Fig. 4

(a) Digital bone landmark identification: 1–2 teardrop, 3–4 tip of lesser trochanter, 5 centre of pubic-symphysis, 6–8 top, fovea and bottom of femoral head, 9 acetabular posterior wall, 10–11 external femoral cortex. (b) Geometrical software output: horizontal and vertical. (c) Final templating: implant, size, shape and position.

Fig. 5

Spino-pelvic parameters: red pelvic tilt, green sacral slope, blue pelvic incidence.

Fig. 6

The transverse acetabular ligament (TAL) (a) anatomical description; (b) intraoperative picture showing cup cradled by TAL, and (c) parallel to TAL.