Dual Mobility in Extreme Situations of Revision Hip Arthroplasty: A Case Series of 3 Cases and Review of Literature

Introduction: Dual mobility (DM) total hip replacement (THR) features an acetabular component with an unconstrained tripolar build which ensures a greater range of motion without provoking any dislocation.We report three cases with extremes of surgical misadventure where we carried out a revision arthroplasty with a DM cup. The causes of the failure of the primary arthroplasty were multifactorial, even individually, and ranged from instability due to component malposition, trochanteric fracture, intrapelvic prosthesis protrusion, etc.

Case report: (1) Case 1 is a 40-year-old male, who following a failed fixation of a right proximal femur shaft fracture had undergone a proximal femur replacement outside with a proximal femur bipolar prosthesis and presented with a dislocated prosthesis due to excessive anteversion of 40 of the stem. Revision was done by inserting a DM cup without revising the stem to preserve the valuable femoral bone stock. (2) Case 2 is an 84-year-old comorbid female, who had come with right protrusio acetabuli with bipolar prosthesis in situ. The patient was managed with bone grafting and insertion of a DM cup with a peripheral fit. Greater trochanter wiring was done for the greater trochanter fracture (GTF) along with prophylactic posterior column plating. (3) Case 3 is a 60-year-old male, who had left sided chronic THR instability. He has had three previous episodes of dislocation which started after 7 years, when the patient fell and had a GTF. Here, the causes of instability were multifactorial- GTF, malposition, and liner wear. Instead of using a constrained liner and predisposing the patient to impingement, we did an isolated revision with a DM cup only.

Conclusion: The presented cases highlight the versatility and efficacy of utilizing a DM cup in revision arthroplasty for addressing diverse causes of primary hip arthroplasty failure. The adaptability is demonstrated in preserving the bone stock, managing bone loss, and addressing multifactorial instability, thereby emphasizing its widespread potential.