3D Printing Aids Acetabular Reconstruction in Complex Revision Hip Arthroplasty

Abstract

Revision hip arthroplasty requires comprehensive appreciation of abnormal bony anatomy. Advances in radiology and manufacturing technology have made three-dimensional (3D) representation of osseous anatomy obtainable, which provide visual and tactile feedback. Such life-size 3D models were manufactured from computed tomography scans of three hip joints in two patients. The first patient had undergone multiple previous hip arthroplasties for bilateral hip infections, resulting in right-sided pelvic discontinuity and a severe left-sided posterosuperior acetabular deficiency. The second patient had a first-stage revision for infection and recurrent dislocations. Specific metal reduction protocols were used to reduce artefact. The images were imported into Materialise MIMICS 14.12®. The models were manufactured using selective laser sintering. Accurate templating was performed preoperatively. Acetabular cup, augment, buttress, and cage sizes were trialled using the models, before being adjusted, and resterilised, enhancing the preoperative decision-making process. Screw trajectory simulation was carried out, reducing the risk of neurovascular injury. With 3D printing technology, complex pelvic deformities were better evaluated and treated with improved precision. Life-size models allowed accurate surgical simulation, thus improving anatomical appreciation and preoperative planning. The accuracy and cost-effectiveness of the technique should prove invaluable as a tool to aid clinical practice.

Figure 1

CT scan showing bilateral first-stage revision THR prostheses with right-sided pelvic discontinuity and a severe left-sided posterosuperior acetabular deficiency.

Figure 2

3D CT reconstruction showing a dislocated left-sided THR secondary to a posterior acetabular wall deficiency.

Figure 3

3D pelvic image created from the CT scan using Materialise MIMICS 14.12.

Figure 4

Segmenting the femur from the acetabulum using Materialise MIMICS 14.12.

Figure 5

Segmenting the femur from the acetabulum using Materialise MIMICS 14.12.

Figure 6

Thresholding of the pelvis and femoral bones.

Figure 7

Thresholding and segmenting (deleting) the femoral bones from the pelvis.

Figure 8

Thresholding and segmenting (deleting) the femoral bones from the pelvis.

Figure 9

Support bars were drawn across the symphysis pubis and sacroiliac joints to avoid separation on printing the model.

Figure 10

A life-size 3D printed model of the first patient's pelvis, providing the surgeon with visual and tactile appreciation of the defects in situ (note: these figures in print journal are two-dimensional, thus limiting the true demonstration of the value of 3D printed models in providing an accurate understanding and representation of the complex deformities and corrective reconstructive techniques).

Figure 11

Examining the left acetabulum showing a posterosuperior deficiency. The right acetabulum shows significant central discontinuation due to bone loss (note: these figures in print journal are two-dimensional, thus limiting the true demonstration of the value of 3D printed models in providing an accurate understanding and representation of the complex deformities and corrective reconstructive techniques).

Figure 12

Examining the left acetabulum showing a posterosuperior deficiency. The right acetabulum shows significant central discontinuation due to bone loss (note: these figures in print journal are two-dimensional, thus limiting the true demonstration of the value of 3D printed models in providing an accurate understanding and representation of the complex deformities and corrective reconstructive techniques).

Figure 13

Preoperative templating, implant sizing, and surgical stimulation (note: these figures in print journal are two-dimensional, thus limiting the true demonstration of the value of 3D printed models in providing an accurate understanding and representation of the complex deformities and corrective reconstructive techniques).

Figure 14

Preoperative templating, implant sizing, and surgical stimulation (note: these figures in print journal are two-dimensional, thus limiting the true demonstration of the value of 3D printed models in providing an accurate understanding and representation of the complex deformities and corrective reconstructive techniques).

Figure 15

Preoperative templating, implant sizing, and surgical stimulation (note: these figures in print journal are two-dimensional, thus limiting the true demonstration of the value of 3D printed models in providing an accurate understanding and representation of the complex deformities and corrective reconstructive techniques).

Figure 16

Postoperative anteroposterior pelvic plain film radiographs showing second-stage THR revisions in situ.

Figure 17

Postoperative anteroposterior pelvic plain film radiographs showing second-stage THR revisions in situ.