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Use of ceramic head in total hip revision decreased symptoms of ALTR
By recognizing ALTR early, presenter said orthopedic surgeons can prevent extensive soft tissue damage around the hip.
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DALLAS — Retention of a well-fixed stem and modular exchange to a ceramic head led to resolution of symptoms and decreased metal ion levels among patients with a metal-on-polyethylene bearing who experienced an adverse local tissue reaction secondary to corrosion at the head-neck taper, according to results presented at the American Association of Hip and Knee Surgeons Annual Meeting.
“We have been studying tribocorrosion at modular junctions for more than 2 decades. It has only been in the last few years that we have recognized that this process can lead to adverse local tissue reactions (ALTRs),” Joshua J. Jacobs, MD, from Rush University Medical Center, said during an interview following a presentation of these findings.
Treatment of ALTR
Jacobs and his colleagues identified 27 patients revised for an ALTR secondary to corrosion at the modular femoral head-neck junction with a metal-on-polyethylene bearing. Twenty-three of the patients were treated with debridement and a modular bearing exchange with use of a ceramic femoral head with a titanium sleeve.
Joshua J. Jacobs
Results showed preoperative serum cobalt levels were elevated to a greater degree than chromium levels in all cases. However, metal studies showed a significant decrease in serum cobalt from a mean of 11.2 ppb to a mean of 0.33 ppb and of chromium from a mean of 2.2 ppb to a mean of 0.51 ppb following modular head exchange. Researchers found significant improvement in the mean Harris Hip score from 56.5 to 86.5 points.
Two of the earliest patients treated experienced a recurrence of ALTR after receiving a metal head during the first revision. Both patients presented with pain and advanced imaging was consistent with the finding of recurrence of ALTR. Both patients’ pain was relieved after re-revision to a ceramic head. Other complications included recurring postoperative instability in two patients, periprosthetic joint infection treated with a two-stage exchange in one patient and a peroneal nerve palsy in one patient.
“In our experience, only 4% of the revision total hips performed at our institution were done for ALTR resulting from tribocorrosion at the modular junction. If the orthopedic surgeon is aware of this entity and recognizes it early, the modular exchange can be done before there is extensive soft tissue damage to the tissues around the hip,” Jacobs told Orthopedics Today. “So far, at relatively early follow-up, addressing the problem by replacing the metal head with a ceramic head and a titanium sleeve has been successful.”
Future research
In the future, Jacobs and his colleagues will continue to follow these patients with clinical evaluations and serum metal levels. Through additional research, the authors aim to determine the pathogenesis of this process.
“Further understanding of the mechanistic basis of ALTRs in association with tribocorrosion of modular junctions can be obtained by laboratory studies, analytical models and implant retrievals in correlation with clinical findings,” Jacobs said during the interview. “With this comprehensive approach, we can identify and develop strategies to prevent or minimize this pathological process.” – by Casey Tingle
Reference:
Plummer DR. Paper #22. Presented at: American Association of Hip and Knee Surgeons Annual Meeting. Nov. 6-9, 2014; Dallas.
For more information:
Joshua J. Jacobs, MD, can be reached at Rush University Medical Center, 1725 W. Harrison St., Chicago, IL 60612; email: joshua.jacobs@rushortho.com.
Disclosure: Jacobs has stock options in Implant Protection; received research support from Medtronic, Zimmer and NuVasive; and is on the board of directors for the American Academy of Orthopaedic Surgeons.