From the Guidelines
The best treatment for protrusio acetabuli occurring during reaming in Total Hip Arthroplasty (THA) is immediate cessation of reaming followed by medial wall reconstruction. When protrusio is identified, the surgeon should stop reaming and assess the defect. For small defects, cancellous bone graft harvested from the femoral head or acetabular reamings can be impacted into the defect. For larger defects, structural support may be required using mesh or a reconstruction cage along with bone grafting. After reconstruction, a larger acetabular component should be selected to bypass the defect and achieve stable fixation in the remaining intact bone. The cup should be positioned to restore the hip's center of rotation laterally. Postoperatively, weight-bearing restrictions (typically toe-touch or partial weight-bearing for 6-12 weeks) should be implemented to allow for graft incorporation. This approach addresses the immediate structural compromise while promoting biological healing of the medial wall. The reconstruction restores acetabular integrity, prevents further medial migration of the hip joint, and provides a stable foundation for the acetabular component, which is essential for long-term implant survival and function. Some key points to consider in the management of protrusio acetabuli include:
- Immediate cessation of reaming to prevent further damage
- Assessment of the defect to determine the appropriate reconstruction technique
- Use of cancellous bone graft or structural support as needed
- Selection of a larger acetabular component to achieve stable fixation
- Positioning of the cup to restore the hip's center of rotation laterally
- Implementation of weight-bearing restrictions postoperatively to allow for graft incorporation. Although the provided study 1 discusses the treatment of pathologic fractures and impending fractures, it does not directly address the treatment of protrusio acetabuli occurring during reaming in THA. However, the principles of fracture stabilization and reconstruction can be applied to the management of protrusio acetabuli, with a focus on restoring acetabular integrity and achieving stable fixation of the acetabular component.
From the Research
Treatment Options for Protrusio Acetabuli
- The use of a Ganz reinforcement ring combined with a bone graft and plating of the posterior column and/or screws for the anterior column has been shown to be a successful treatment option for protrusio acetabuli occurring during reaming in Total Hip Arthroplasty (THA) 2.
- Lateralized cementless porous-coated components supported on the peripheral acetabular bony rim, along with morsellized autograft to fill the medial defect, can also be effective in treating protrusio acetabuli 3.
- In cases where the acetabular rim is inadequate to provide mechanical support for a cementless cup, a reconstruction cage may be a more appropriate option to gain fixation to the pelvis above and below the acetabulum 3, 4.
- Bone-grafting, using either homologous or autogenous bone grafts, has been used to reinforce the medial acetabular wall in patients with protrusio acetabuli, with successful results in arresting the progression of acetabular protrusion 5.
Surgical Considerations
- Proper acetabular preparation is critical to successful THA, and a systematic approach to acetabular preparation can help maximize reproducibility 6.
- Careful preoperative templating is important to help determine implant position and avoid complications such as medial migration or leg length discrepancy 3.
- The use of structural augmentation, custom components, or cage reconstruction may be necessary for managing larger defects with severe loss of acetabular bone stock 4.