I received several responses….From Lucas Da Gama Lobo, I found this most detailed and useful:I think this is ALTR. I understand ATLR is an umbrella term encompassing a variety of immune mediated reactions to metal wear debris in patients with arthroplasties, commonly those incorporating a metal on metal bearing, though an identical reaction can occur at modular junctions of traditional implants. The type and severity of reaction is mediated by an interaction between host immune response with the type and volume of wear debris. In patients with an immune predisposition metal debris may provoke an aggressive type IV hypersensitivity reaction mediated by lymphocytes, known as ALVAL. This process may result in rapid periprosthetic soft tissue destruction and less commonly osteolysis. I think we see both in your case. Metal debris and corrosion products may present without provoking an aggressive hypersensitivity-type reaction in patients who are not immunologically predisposed. In these cases metal deposition results in metallosis, a foreign body reaction which is typically more indolent than ALVAL. Hope that helps.
43M underwent resurfacing arthroplasty of the right hip 2 years agoThese XRs are 16 months ago (I have no prior post op XRs)
Current CT shows extensive periprosthetic erosion / bone loss at the acetabulum and proximal femur, with punctate metallic foci posterior to the hip
There is low attenuation soft tissue thickening / capsular distention surrounding the hip
My questions / comments:
1. Osteolysis typically occurs years after arthroplasty…infection typically occurs within the first year (usually early in the first year)….the features look typical of osteolysis…
2. Would you call this Osteolysis, ALTR, ALVAL ? I’m really not clear on the difference and if it is important to distinguish among these
3. I recall there was a run of resurfacing complications and this seemed to have fallen out of favor, but I have recently seen more of these….presumably there have been design improvements? I presume that the prostheses that had high rates of failure and were removed from the market preceded his arthroplasty 2 years ago (do you know?)
4. Considering that this is generally reserved for younger patients (usually men) with good bone stock, this is a tragic complication
According to Orthobullets
Outcomes
Variable outcome findings in the literature (79% to 98% success rate)
Better results found in patients young, larger males with excellent bone stock treated for osteoarthritis than for dysplasia or osteonecrosis
Some case series have shown survival comparable to conventional THA, while others have reported higher rates of early revision
some products have been removed from the market due to early failure
More recent prospective trials have shown few differences between resurfacing and THA
