Knee Replacement Offers Little Benefit, Study Suggests

Marisa Wexler, MS avatar

by Marisa Wexler, MS |

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People with Parkinson’s disease who have arthritis in their knees report minimal improvements in life quality after undergoing knee replacement surgery, a new study reports.

“Data from this study suggest that [total knee replacement] has no clinical benefit in improving [quality of life] beyond a slight improvement in pain-related disability in the [Parkinson’s] population,” its researchers wrote.

The study, “Quality of life assessment after total knee arthroplasty in patients with Parkinson’s disease,” was published in BMC Musculoskeletal Disorders.

A knee replacement, also called total knee arthroplasty (TKA), is a surgery done to help reduce pain and improve functionality in people with severe arthritis of the knee. TKA can significantly improve life quality in the overall population, but whether it may benefit people with Parkinson’s who have co-occurring knee arthritis is less clear — particularly since motor symptoms of Parkinson’s can increase the likelihood of complications after surgery.

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To learn more, scientists at Bao Di Hospital in China conducted a retrospective review of patients who had undergone TKA at their institution. The review included 60 people who had undergone TKA, 12 with Parkinson’s and 48 without. All of these patients were followed for just more than a year on average.

To assess how TKA affected life quality, the researchers used three standardized assessments: the Pain and Disability Questionnaire (PDQ), which assesses pain-induced disability and difficulty with daily tasks; the Patient Health Questionnaire-9 (PHQ-9), which measures depression; and the EuroQOL5-Dimensions (EQ-5D), which assesses mobility, self-care, daily activities, pain, and mental health.

Prior to undergoing knee replacement surgery, scores on all of these assessments were similar among the patients with and without Parkinson’s.

Among the patients who did not have Parkinson’s, all of the measures of life quality improved significantly following TKA. The EQ-5d index increased from 0.545 to 0.717, indicating better overall health. PDQ decreased from 81.1 to 52.3, suggesting less pain and impairment. PHQ-9 decreased from 8.22 to 5.91, representing less depression.

By contrast, among the Parkinson’s patients, EQ-5D and PHQ-9 scores decreased slightly following TKA, but the change was not statistically significant. PDQ scores did decrease significantly after TKA in the Parkinson’s group, but the change was markedly less dramatic than in the non-Parkinson’s group — from 91 before surgery, to 81.4 at the end of follow-up after a little more than a year.

Notably, although scores before surgery were similar, Parkinson’s patients had significantly worse quality of life after surgery. Further statistical analyses showed that Parkinson’s disease was an independent predictor of a lessened improvement in EQ-5D scores after knee replacement surgery.

“These results indicate that patients with PD have a poorer improvement in [quality of life] after TKA compared to patients with KOA alone, but still relieve symptoms or pain related disability,” the researchers wrote.

The researchers stressed that this is a small, retrospective study, so more research is needed to validate the results. Nonetheless, the team posited several potential explanations for why this surgery might not yield much noticeable benefit.

“It is possible that the disease burden associated with Parkinson’s disease limits improvement in QOL, even if KOA symptoms are alleviated. And another explanation may be that postoperative physical therapy is ineffective in PD patients,” the scientists wrote.

They added that “it is possible that the specific gait changes and postural stability of PD in patients make TKA treatment less effective than expected.”