Clinical Scorecard: Association of Femoral Stem Selection with Patient Outcomes and Longevity Following Conversion Total Hip Arthroplasty: A Retrospective Study and Innovative Treatment Protocol

At a Glance

Key Highlights

• cTHA survivorship is lower and complication rates higher compared to primary THA, resembling revision THA outcomes.
• Femoral stem types used include uncemented diaphyseal-engaging, uncemented metaphyseal-engaging, and cemented stems, with cemented stems more common in older patients.
• Prior fracture fixation method and fracture pattern influence femoral stem selection, but impact on survivorship and PROMs remains unclear.

Guideline-Based Recommendations

Diagnosis

• Use AO/OTA classification to identify proximal femoral fracture patterns eligible for cTHA.
• Perform preoperative radiographic evaluation to assess fracture pattern, fixation implant, and signs of osteoarthritis.
• Evaluate stem fixation and loosening via calibrated radiographs postoperatively.

Management

• Select femoral stem type (diaphyseal-engaging, metaphyseal-engaging, or cemented) based on patient age, fracture pattern, and prior fixation construct.
• Consider cemented stems preferentially in older patients.
• Use posterior approach for cTHA surgery.

Monitoring & Follow-up

• Monitor for stem subsidence ≥5 mm on serial radiographs as significant.
• Assess clinical variables including anterior thigh pain, limp, limb length discrepancy, wound complications, and range of motion at follow-up.
• Collect patient-reported outcome measures such as HOOS, JR. preoperatively and at 1 year postoperatively.

Risks

• Higher complication rates and lower survivorship compared to primary THA.
• Worse functional outcomes in patients with prior CMN fixation compared to extramedullary fixation.
• Potential for stem loosening and subsidence post-cTHA.

Patient & Prescribing Data

51 patients (mean age 73 years, BMI 27.5) undergoing cTHA after proximal femoral fracture fixation

Majority received uncemented diaphyseal-engaging stems; cemented stems used in older patients; dual mobility and standard polyethylene liners equally used; mean follow-up 69 months.

Clinical Best Practices

• Perform thorough preoperative radiographic assessment including measurement of stem bypass distance relative to prior screw holes to guide stem choice.
• Tailor femoral stem selection to fracture pattern, prior fixation method, and patient age to optimize outcomes.
• Use standardized outcome measures (HOOS, JR.) to evaluate functional recovery post-cTHA.
• Maintain vigilance for postoperative complications and stem subsidence through regular clinical and radiographic follow-up.

References

• Arbeitsgemeinschaft für Osteosynthesefragen (AO)/Orthopaedic Trauma Association (OTA) fracture classification
• Hip dysfunction and Osteoarthritis Outcome Score for Joint Replacement (HOOS, JR.)