High incidence of pain common 1 year following TKA

Issue: May 2016

Patients who underwent total knee arthroplasty experienced a high incidence of pain at 1 year postoperatively, according to recently published study results.

Perspective from William G. Hamilton, MD

“The quality of the results, hip vs. knee, is different and we still have not answered all the questions in knee replacement surgery as to why the outcomes in knee replacement surgery are not as good,” Surgeon-in-Chief Emeritus at the Hospital for Special Surgery, Thomas P. Sculco, MD, told Orthopedics Today. “There is a population ... that does less well and so the surgeon [should] advise the patients where the results may potentially not be as good.”

Knee pain

Sculco and his colleagues identified 272 patients who underwent primary total knee arthroplasty (TKA) from October 2006 to August 2008 with a minimum 1-year follow-up. The prevalence of persistent pain was the primary outcome measure, and researchers evaluated postoperative pain using the 10-point VAS score. All patients completed a SF-36 questionnaire to identify persistent postoperative pain.

Overall, 39.34% of patients reported persistent knee pain with a median average pain score of 3. Women, patients with increased preoperative posterior femoral offset, patients who needed a greater amount of correction in the anatomical axis of the knee, had an everted patella during the procedure, a thicker polyethylene insert and use of a more constrained implant were found to experience worse SF-36 scores.

Chronic pain was significantly associated with the presence of antalgic gait preoperatively, patellofemoral joint overstuffing and the amount of correction in the coronal plane, according to univariate logistic regression analysis. Researchers also found length of the operative procedure, presence of preoperative flexion contracture and patellofemoral joint overstuffing were independent risk factors for persistent pain.

“[All] of us who do knee replacement surgery [are] working hard to make the outcomes better than they are and we recognize we have some work to do going forward, both in our research, our technique and identification of patients who do not do well,” Sculco said.

Identifying high-risk patients

Sculco noted the Knee Society is working on determining which patients are at higher risk to develop scarring and stiffness around the knee after TKA. By identifying these patients, surgeons could modify their surgical technique and how patients are treated postoperatively.

“I think that the ideal would be if we had a marker,” Sculco said. “You could draw blood on a patient, and if there was a serum marker or you could genetically profile the patient and identify this patient is at higher risk to have problems with stiffness or persistent pain afterwards. That is the goal and that is certainly what we are working on for the future.” – by Casey Tingle

Reference:
Sakellarious VI, et al. Orthopedics. 2016;doi:10.3928/01477447-20151228-06.

For more information:
Thomas P. Sculco, MD, can be reached at Hospital for Special Surgery, 525 East 71st St., 2nd Fl., New York, NY 10021; email: sculcot@hss.edu.

Disclosure: Sculco reports he receives royalties from Exactech.

Perspective

William G. Hamilton, MD

The article demonstrates how persistent pain following total knee arthroplasty (TKA) is more common than most patients and surgeons expect. Having this data can help set appropriate patient expectations and subsequently improve patient outcomes, without changing the amount of pain involved. Knowing there are patient factors such as diabetes and the presence of a preoperative flexion contracture that predicted postoperative pain can help set expectations. Another interesting finding is there were few surgeon-controlled factors that seemed to influence outcomes. While longer operative times predicted higher postoperative pain scores, this may be a marker for other factors, such as higher case complexity or intraoperative events, and not a call to surgeons to start rushing through their surgeries. The more data we have that educates us on what leads to suboptimal outcomes, the better we can target improving the results of this important procedure.

William G. Hamilton, MD

Orthopedics Today Editorial Board member

The Anderson Orthopaedic Clinic

Alexandria, Va.

Disclosures: Hamilton reports he is a paid consultant and presenter for and receives research support and intellectual property royalties from DePuy. He also is a paid consultant for and receives intellectual property royalties from Total Joint Orthopedics and receives research support from Zimmer Biomet and Inova Health Care Services.