Stem length in primary cementless total hip arthroplasty: Does it make a difference in bone remodeling?

Area of Science:

• Orthopedic Surgery
• Biomaterials Science
• Radiology

Background:

• Proximal femoral remodeling is a concern after total hip arthroplasty (THA).
• Stem design is often implicated in periprosthetic bone density changes.
• Cementless femoral stems are widely used in THA.

Purpose of the Study:

• To prospectively compare in vivo bone mineral density (BMD) changes in the proximal femur.
• To evaluate the impact of two different lengths of cementless femoral stems on BMD.
• To assess clinical and radiological outcomes of standard versus short stems in THA.

Main Methods:

• A prospective randomized study involving 50 patients undergoing cementless THA.
• Patients were allocated to receive either standard or short cementless femoral stems.
• Bone mineral density (BMD) was assessed using dual-energy X-ray absorptiometry (DXA) over a mean follow-up of 21.4 months.

Main Results:

• Both standard and short stems showed a decrease in proximal femur BMD, with greater loss in the greater trochanter region.
• Mean overall BMD decreased by 11.26% for standard stems and 8.68% for short stems.
• No significant differences were observed between groups in clinical scores (HHS, VAS), radiological outcomes, or complication rates.

Conclusions:

• Cementless short stems did not prevent proximal femoral bone loss following THA.
• Short stems may modify or decrease the incidence of bone loss compared to standard stems, but do not eliminate it.
• Further research is needed to optimize stem design for preserving periprosthetic bone density.