Chronic asymptomatic dislocation of a total hip replacement: a case report

Area of Science:

• Orthopedic Surgery
• Biomedical Engineering

Background:

• Total hip arthroplasty (THA) is a common procedure for hip joint issues.
• Prosthetic hip dislocation is a significant complication, with reported incidence ranging from 0.5% to 20%.
• While early dislocation is common, late dislocation occurring years after surgery is increasingly recognized.

Purpose of the Study:

• To present a unique case of late, asymptomatic prosthetic hip dislocation.
• To highlight the potential for neoacetabulum formation in dislocated THA.
• To emphasize the importance of regular radiographic follow-up for detecting late complications.

Main Methods:

• Case report of a 60-year-old male patient who underwent right Exeter cemented total hip replacement.
• Patient presented 8 years post-surgery with left groin pain, revealing a dislocated right THA on pelvic X-ray.
• Radiographic analysis showed the dislocated femoral component articulating within a newly formed acetabulum (neoacetabulum).

Main Results:

• The patient experienced a pain-free right hip with a good range of motion despite the dislocation.
• A significant leg length discrepancy (5 cm) was noted.
• The dislocated femoral component had formed a functional neoacetabulum within the ilium.

Conclusions:

• A dislocated total hip replacement can be asymptomatic and maintain function through neoacetabulum formation.
• This case underscores the potential for missed complications with shorter follow-up periods.
• A high index of suspicion and regular radiographic monitoring are crucial for identifying late THA complications.