Component Asymmetry in Bilateral Cementless Total Hip Arthroplasty

Area of Science:

• Orthopedic Surgery
• Biomedical Engineering
• Radiology

Background:

• Component asymmetry (CA) is a potential concern in bilateral cementless total hip arthroplasty (THA).
• Understanding the incidence and impact of CA is crucial for optimizing patient outcomes.
• Previous research has not extensively detailed the radiologic and clinical implications of CA in THA.

Purpose of the Study:

• To investigate the incidence and outcomes of component asymmetry (CA) in patients who underwent bilateral cementless total hip arthroplasty (THA).
• To compare radiologic and clinical results between patients with component symmetry (CS) and component asymmetry (CA).
• To identify factors associated with CA, such as the time interval between operations.

Main Methods:

• A cohort of 300 patients undergoing bilateral cementless THA between 2000 and 2017 was retrospectively analyzed.
• Patients were categorized into component symmetry (CS) and component asymmetry (CA) groups.
• The CA group was further sub-classified into acetabular component asymmetry (ACA) and femoral component asymmetry (FCA); radiologic and clinical outcomes were compared.

Main Results:

• The incidence of CA was 25.7%, with ACA being more common than FCA.
• A significantly longer time interval between operations was observed in the CA group compared to the CS group.
• Despite CA, mean Harris Hip Scores were similar between the CA and CS groups, indicating comparable functional outcomes.

Conclusions:

• Component asymmetry is not uncommon in bilateral cementless THA, particularly with longer intervals between surgeries.
• Achieving stable component fixation is paramount for obtaining satisfactory radiologic and clinical outcomes, irrespective of component alignment.
• Further research may explore strategies to minimize CA and its potential long-term effects.