ABOS Part I Comprehensive Review - Batch 17

Question 1

A 72-year-old male presents with worsening left groin and thigh pain 15 years after a primary THA. His initial radiographs show significant superior migration of the acetabular component with superior pole osteolysis and a wide lucent line at the bon

Accepted Answer

Aseptic Loosening with Osteolysis

Question 2

Based on the CT scan findings described in the case, the acetabular bone defect is classified as Paprosky Type IIIA. Which of the following best describes the key characteristics of a Paprosky Type IIIA acetabular defect?

Accepted Answer

Extensive superior segmental and cavitary bone loss, with a deficient superior dome and often medial wall perforation.

Question 3

The CT scan also confirmed a Paprosky Type IIB femoral bone defect. Considering this classification, what is the most appropriate surgical strategy for femoral reconstruction in this patient?

Accepted Answer

A long, modular, uncemented femoral stem designed for diaphyseal fixation, bypassing proximal bone loss.

Question 4

The patient's pre-operative workup included a dedicated CT scan of the pelvis and bilateral hips with thin cuts and metal artifact reduction protocols. What is the primary reason for obtaining this specific imaging study in a complex revision THA cas

Accepted Answer

To precisely define the extent and morphology of bone defects, delineate osteolytic lesions, and plan for component removal and reconstruction.

Question 5

During the surgical intervention, a greater trochanteric osteotomy was performed. What is the primary rationale for utilizing a greater trochanteric osteotomy in this specific complex revision total hip arthroplasty?

Accepted Answer

To facilitate unparalleled exposure of the femoral canal and acetabulum, especially for cement and component removal.

Question 6

For the acetabular reconstruction in this Paprosky Type IIIA defect, a modular trabecular metal dome augment was selected. What is the primary advantage of using such an augment in this specific scenario?

Accepted Answer

To provide structural support for the deficient superior dome, restore the hip center, and allow for stable screw fixation into host bone.

Question 7

Following the successful removal of the femoral component and cement, the surgeon performed cancellous allograft bone chip impaction grafting into the proximal femur. What is the main objective of this technique in the context of a Paprosky Type IIB

Accepted Answer

To reconstruct the metaphyseal bone loss, provide a biological scaffold for bone healing, and support trochanteric reattachment.

Question 8

Post-operatively, the patient was prescribed protected weight-bearing (toe-touch or 20% partial weight-bearing) for 6 weeks. What is the most critical reason for this specific weight-bearing restriction in this complex revision THA?

Accepted Answer

To allow for bone ingrowth and healing of the acetabular augment fixation and trochanteric osteotomy.

Question 9

During the component removal phase of this complex revision, the removal of the remaining cement mantle was identified as the most challenging part. Which of the following 'pearls' from the case study is most critical to avoid a significant pitfall d

Accepted Answer

Meticulous removal of all residual cement from the femoral canal using specialized tools while preserving host bone stock.

Question 10

Given the extensive soft tissue dissection and the performance of a greater trochanteric osteotomy during this complex revision THA, which of the following post-operative complications is the patient at a significantly increased risk for, and what pr

Accepted Answer

Heterotopic Ossification (HO); prophylaxis with NSAIDs or radiotherapy.

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Key Takeaway