What are the recommended versions of hip replacement and their importance?

Hip Replacement Versions and Their Clinical Importance

Primary Prosthesis Types

The two main bearing surface combinations for total hip replacement are cemented versus uncemented fixation, and ceramic-on-ceramic (COC) versus ceramic-on-polyethylene (COP) articulations, with choice primarily determined by patient age and bone quality rather than superior clinical outcomes. 1

Cemented vs. Uncemented Prostheses

• In younger patients, uncemented prostheses are generally preferred because later revisions are technically easier due to preserved bone structure, though the difference in long-term durability between cemented and uncemented hip prostheses is not large 1

• Cemented femoral stems should be used in patients with compromised bone quality, particularly in elderly patients with fragility fractures 2

• The choice between cemented and uncemented fixation has no comparative studies specifically in ankylosing spondylitis patients, despite their unique bone quality considerations 1

Bearing Surface Options

• Ceramic-on-ceramic (COC) articulations demonstrate superior wear resistance compared to ceramic-on-polyethylene (COP), but this theoretical advantage does not translate into clinically meaningful differences in hip function, loosening rates, dislocation rates, revision rates, or osteolysis rates 3, 4

• COC bearings have significantly higher rates of prosthesis fracture and squeaking sounds compared to COP bearings, which represents a quality-of-life consideration 3

• COP bearings show higher wear rates than COC, but polyethylene wear debris remains a concern for long-term osteolysis and aseptic loosening 3, 4

• At 2-year follow-up in a randomized trial of 444 patients, clinical and radiographic outcomes between COC and COP groups were comparable, with no spontaneous ceramic bearing failures observed 4

Clinical Outcomes and Importance

Pain Relief and Function

• Total hip replacement achieves 43-84% pain-free outcomes at 9.4-year follow-up, with mean Harris hip score improvements ranging from 36% to 46% from baseline 5, 2

• Despite high overall satisfaction, 27% of patients experience some discomfort and up to 6% experience severe chronic pain after THR 6

• The strength of recommendation for total hip replacement is 86% based on expert consensus, despite only category III evidence for efficacy, reflecting the overwhelming clinical experience supporting this intervention 1

Revision Rates

• Revision rates are acceptable at 0.18-2.04 per 100 person-years when adjusted for age, sex, and type of hip arthritis 5, 2

• Age and sex predict revision rates in total hip arthroplasty, but revision rates in ankylosing spondylitis patients are not unduly high 1

Critical Surgical Considerations

Patient Selection

• Total hip replacement should be considered in patients with refractory pain or disability and radiographic evidence of structural damage, independent of age 1

• For displaced femoral neck fractures in healthy, active, and independent older individuals without cognitive dysfunction, total hip replacement is preferred over hemiarthroplasty 1

• In frail patients with femoral neck fractures, hemiarthroplasty may be preferred due to shorter operative time and lower dislocation risk, though functional outcomes are less optimal 1

Preoperative Planning

• Obtain CT without IV contrast before surgery to assess joint congruence, component positioning requirements, intraarticular fracture fragments, acetabular wall fractures, and bony impingement mechanisms 2

• Add MRI without IV contrast if soft tissue pathology assessment is needed, particularly for evaluating abductor tendon integrity and muscle injuries that may compromise stability 2

Perioperative Management

• NSAID treatment does not need to be discontinued for total hip arthroplasty surgery, as administration on the evening before surgery does not affect perioperative bleeding or complication rates 1

• Heterotopic ossification rates are not increased in ankylosing spondylitis patients, and routine preoperative NSAID prophylaxis is standard practice 1

• Multimodal analgesia with preoperative nerve blocks facilitates early mobilization while maintaining hip precautions 2

Common Pitfalls

• There is no high-quality randomized controlled trial evidence comparing total hip replacement to non-operative care, as ethical and practical issues prevent blinding of surgical treatments 1

• The high-profile failure of metal-on-metal prostheses has exposed shortcomings in the existing regulatory framework for implant approval 7

• Current treatments cannot reverse hip osteoarthritis or restore damaged cartilage—they only control symptoms and improve function 5, 2

• Joint-preserving procedures (osteotomy, arthroscopic debridement) only redistribute mechanical forces and do not reverse existing damage, making them inappropriate for advanced disease 5, 2