The JBJS Quiz of the Month is a collection of 10 relevant questions from each orthopaedic subspecialty. The questions are drawn from JBJS Clinical Classroom, which houses over 4,500 questions and 3,100 learning resources. Take the Quiz to see how you score against your peers!

NOTE: This quiz does not earn users CME credits. The questions must be answered within Clinical Classroom to earn CME credits.

A 55-year-old male patient who had left total hip arthroplasty (THA) 5 years ago with a metal-on-metal bearing surface develops progressive pain and a Trendelenburg gait over a 1-year period. Which of the following is the most likely cause of this gait pattern?
    • Trochanteric bursitis
    • Trochanteric bursitis can occur after THA but would cause pain over the greater trochanter that is worse with sitting or lying on the operative side, and it is not usually associated with weakness or limping.


    • Infection
    • Given this patient’s gradually worsening symptoms and history of metal-on-metal bearing surface, infection is less likely than the bearing surface as being the cause of his limp. However, it is important to rule out infection in any case of a painful total hip arthroplasty.


    • Iliopsoas tendinitis
    • Iliopsoas tendonitis would cause pain with resisted hip flexion.


    • Abductor insufficiency secondary to adverse local tissue reaction
    • An adverse local tissue reaction (ALTR) from metal ions released from his metal-on-metal bearing surface is the most likely cause of this patient’s abductor weakness causing a Trendelenburg gait. The next steps would be ruling out infection, checking his metal ion levels, and obtaining appropriate imaging to evaluate for the presence of a pseudotumor.