Cementless porous-coated anatomic medullary locking total hip prostheses

Area of Science:

• Orthopedics
• Biomaterials Science
• Surgical Innovation

Background:

• Cementless total hip arthroplasty (THA) aims for long-term implant stability through bone integration.
• The Anatomic Medullary Locking (AML) hip system is a cementless prosthesis designed for improved intramedullary fit.
• Assessing the long-term performance and potential complications of cementless THA systems is crucial for patient outcomes.

Purpose of the Study:

• To evaluate the 7-year outcomes of the uncemented Anatomic Medullary Locking hip system in primary total hip arthroplasty.
• To assess the relationship between intramedullary fit and bone ingrowth.
• To identify the incidence of periprosthetic osteolysis and polyethylene wear with this specific cementless prosthesis.

Main Methods:

• Prospective study of 50 patients (52 hips) undergoing primary THA with the AML system.
• Minimum 7-year follow-up including clinical assessment (Harris hip score) and radiographic evaluation.
• Analysis of intramedullary stem fit (proximal canal and isthmus) and assessment of bone ingrowth, fibrous tissue ingrowth, and component stability.

Main Results:

• Significant improvement in Harris hip scores from preoperative (59) to 7-year follow-up (91).
• Good press-fit achieved in 79% of hips, with 70% of those demonstrating bone ingrowth.
• High incidence of periprosthetic osteolysis (31% acetabular/femoral, 25% femoral only) and polyethylene wear (23%) observed.

Conclusions:

• The AML system provides good initial fit and bone ingrowth in a majority of cases, leading to improved clinical scores.
• Periprosthetic osteolysis and polyethylene liner wear are significant long-term concerns associated with this cementless prosthesis.
• Further investigation is needed to address the high rates of osteolysis and wear to optimize cementless THA outcomes.