Investigate painful THA to determine if infection, aseptic loosening, other problems are the cause

GENEVA — Today’s techniques to diagnose a hip that is painful following primary total hip arthroplasty are markedly better than those previously available and can provide orthopaedic surgeons with more accurate tools to help their patients who face this problem, according to presenters at a symposium 1 June, moderated by Fares S. Haddad, BSc, MCh (Orth), FRCS (Orth), FRCS (Ed).

“If you are faced with a painful arthroplasty, think infection because it is likely infected and the diagnosis is not easy,” Haddad said.

A significant number of organisms are only identified postoperatively, he said.

 “In any busy unit worldwide, there will still be cases where we do not pick up an organism and have to do revision surgery without having an organism, so we need better technology,” according to Haddad.

 

He noted he usually uses a blood test to test a painful hip after total hip arthroplasty (THA), however, a blood test biomarker is close to becoming available.

Although it is a costly technique to diagnose infected THAs, the alpha-defensin test has a high accuracy when used as a lab test, not for bedside care, Haddad said.

It checks for alpha defensin, a protein produced by neutrophils, and can be used in combination with a C-reactive protein algorithm, he said

 “We now have fantastic modern diagnostics both genetic and fast-computing. The future will be with next-generation sequencing where we will send samples up to a cloud. It will analyse against reference values and it will be able to tell you in a few hours what organism you have and what its sensitivity is likely to be. That is probably going to be the biggest advance in infection,” Haddad said.

 

Carsten Perka, MD, reviewed the advantages of getting a thorough patient history and assessing the patient’s gait, as well as always including infection as a possible cause of pain after THA as well as aseptic loosening.

Perka emphasized the value of imaging a failed THA.

“The standard at my institution is an [anteroposterior] AP view of the pelvis and an AP view of the affected hip,” he said.

A main purpose of imaging is to assess any implant migration.

For that, Perka said, “The gold standard for studies is still the [radiostereometric analysis] RSA.”

The downside of RSA imaging is it can only be used prospectively, he said.

 

Moussa Hamadouche, MD, PhD, reviewed when impingement, subluxation and instability may be the cause of unexplained post-THA pain.

Recurrent THA dislocation is a common indication for revision surgery in his practice.

“Instability remains a major complication. Remember, there is frequent association of several causes. Thirty percent of patients will become re-dislocators and 30% of re-dislocations will occur if you use conventional treatment,” Hamadouche said.

Dual-mobility THA systems are among the best solutions in these cases, he said, but Hamadouche does not recommend them for everyone. – by Susan M. Rapp

Reference:

Haddad F, et al. Symposium: Diagnosing the painful THA, infection, aseptic loosening, soft-tissue and impingement problems. Presented at: 17th EFORT Annual Congress—A combined programme in partnership with swiss orthopaedics; 1-3 June 2016; Geneva.

Disclosures: Haddad reports no relevant financial disclosures. Perka reports he receives IP royalties from and is a paid consultant to Smith & Nephew, is a paid presenter or speaker for Ceramtec, DePuy Synthes and Zimmer Biomet. Hamadouche reports he is a paid consultant to Aesculap/B.Braun, Mathys Ltd.