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High survivorship of revised total knee replacements seen at 13 years
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Survival of revised total knee replacements in 230 patients topped 86% at a mean of 13 years, according to a study presented at the British Orthopaedic Association and Irish Orthopaedic Association Combined Meeting 2011. However, patients who had revision for infection showed lower functional scores.
“It was indeed a complex area and the results are not widely published in the literature,” study presenter Prakash Chandran, FRCS, told Orthopedics Today.
Improvement in revision care
Chandran and colleagues wanted to determine the functional results, complications, implant survival and patient satisfaction after complex revision total knee replacement (TKR). They also sought to determine how different the results of revision procedures when compared to those of primary TKRs. Their ultimate goal was to use the outcome data to inform patients about revision knee procedures.
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Images: Chandran P |
“Previously, when we used to counsel the patient for a revision, we used to tell them, the results are not as good as primary [TKR], the failure rates are high, complications are high, stiffness and pain could continue and patients die sooner,” Chandran said. “[…] But we did not have any concrete large long-term results in the literature to support these figures. In that way, it has improved the information you can provide to the patients.”
Prospective study
Chandran and his colleagues performed a prospective study of 243 revision TKRs performed in 230 patients between 1995 and 2001. The researchers performed revisions using 68 Endolink (Link; Hamburg, Germany) prostheses and 175 TC3 (DePuy; Leeds, England) prostheses for patients from Wrightington Hospital in Wrightington, England. Mean patient age was 69 years and 51% of the group were men. The investigators followed patients for a mean of 13 years. Outcome measurements were Oxford knee, WOMAC, Hospital for Special Surgery, UCLA, SF-12 scores and the Health Status Questionnaire (HSQ), a patient satisfaction questionnaire.
The investigators found that Oxford scores gradually improved between 1 year and 5 years, after which they declined, Chandran noted. The surgeons observed no significant improvements in HSQ, SF-12 or UCLA scores postoperatively.
Revision knee implant survival was 86% at 13 years. Thirty-five patients (14%) underwent additional procedures due to failure from loosening, wear or breakage of implants and knee pain, stiffness or weakness in the muscles. Of these, five patients required above the knee amputations.
The investigators also discovered that patients without infections needed fewer secondary revision procedures (13% vs. 18%) and had better functional scores postoperatively compared to patients with infections.
Limitations, next steps
The study limitations include a lack of control group, Chandran said. Additionally, the investigators used different implants that worked on “two different principles.” The study included the results of three experienced surgeons, so Chandran is uncertain that different units could achieve similar results. The researchers did not blind patients to the type of implant used; however, the final observer was blinded to this information, Chandran said.
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Chandran and colleagues intend to compare the two implant types for design differences. They also plan to analyze patient outcomes based on number of revisions.
“We are going to separate them into different groups based on their number of revisions,” Chandran said. “For example, somebody has a first or second or third revision, is there a difference in outcome? Are people having their first revision doing better than people having two or three revisions?” – by Renee Blisard
Reference:
- Chandran P, Patel K, Hamed Y, et al. A prospective study of revision total knee replacements at a mean follow-up of 11 years. Presented at the British Orthopaedic Association and Irish Orthopaedic Association Combined Meeting 2011. Sept. 13-16. Dublin.
- Prakash Chandran, FRCS, can be reached at the Wrightington Hospital, Hall Ln., Appley Bridge, Wigan, Lancashire WN6 9EP; 00447919403862; email: prakachandran@yahoo.co.uk.
- Disclosure: The research team received funding for this study from the Arthritis Research Trust.