This case study illustrates how new technologies can revitalize old techniques such as the Autologous Graft in the treatment of developmental dysplasia of the hip and resulting acetabular bone loss.

Today, metal augments are often used to address acetabular defects - however in this case we have used an autologous graft - a technique that has fallen from favor due to the challenges associated with the fixation of the acetabulum and the stable fixation of graft while reaming into it.

However this case sees this older technique refreshed thanks to the use of newer technologies. Improved acetabular cup designs now feature high friction coatings that aid initial fixation. In addition, the anterior approach delivers enhanced radiographic control throughout the procedure. We used #Velys from DepuysSynthes to guide acetabular component placement, facilitate graft placement and to guide fixation throughout.

The result is efficient structural support to the acetabular component, uniform incorporation of the graft, a simplified procedure using standard tools and the benefits of immediate weight bearing.

Transcript

A patient with rather advanced osteoarthritis where wear of the acetabulum has occurred with the femoral head falling into a defect in the acetabulum. In this case we see where the normal hip center should be, we see where the femoral head is, and we see the superolateral defect associated with the wear of the acetabulum.

Classically this was managed with grafting, however in the modern age I think most surgeons opt to use metal augments or lean on a high hip center to deal with this problem. One of the benefits of the anterior approach has been to improve upon our radiographic control of the procedure. This technique that we developed took advantage of the development of these high friction porous coatings and the ability to intraoperatively use x-ray to guide implant positioning.

The first step is to identify both radiographically and anatomically the false acetabulum and then the true acetabulum. In this case ball has worn a defect in his superolateral acetabulum into the ilium so the idea is to prep that area for eventual grafting. Typically, the neck cut is made under fluoroscopy, the head neck fragment is extracted and immediately measured. From this measurement we can gauge the size of the defect in the acetabulum.

Immediately we introduce the similar sized reamer into the acetabular defect and use this not to medialize and prepare for an acetabular component but rather just to decorticate the bone or at least get to punctate bleeding to make sure that we have good biologic preparation of the bone to accept a graft. The second step is to take the same reamer and then direct it more distally at the level of the teardrop to place the hip in the anatomic hip center. The definitive acetabular component is then opened and placed in the anatomic hip center in anticipation that there's going to be a large superolateral defect. The goal of fixation however is between the anterior and posterior columns. The definitive acetabular component is opened and placed under direct fluoroscopic control with the goal of replicating appropriate anteversion and inclination as defined by our preoperative plan.

The cup is provisionally secured between the columns and screw fixation is then obtained. Care is taken during application of screws to check and recheck acetabular component position as it is common that the application of very strong screw fixation may create minor alterations in cup position.

We then turn our attention to the femoral head - a reamer or another acetabular component or trial component is used to identify the section of the femoral head that needs to be taken. This takes a little bit of artistic three-dimensional thought - but basically we're looking at a lemon wedge and trimming this to fit the defect. Once the bone graft is provisionally in place we tamp it into position thereby loading the graft, and we secure it with a single, or sometimes two, 3.5 fully threaded cortical screws.

In our hands this has been an efficient way of providing structural support to an acetabular component. The benefits have been almost uniform incorporation of the graft, a simplified procedure that requires nothing more than tools that exist in most ORs throughout the country and the benefits of immediate weight bearing. In this particular case we applied the procedure in a bilateral fashion allowing the patient to fully mobilize immediately after surgery. He was weight-bearing as tolerated without dislocation precautions. His rehabilitation was as per our typical postoperative routine. We hope you find this to be a straightforward and easily applied technique which requires little additional equipment and provides reproducible results as it relates to structural augmentation of the acetabulum component when autologous femoral head is available.

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