Preoperative Mental Health Scores Can Predict Functional Outcomes of Surgery

The common conclusion from 2 studies that were conducted in different countries and used different assessment tools is more notable than their differences: preoperative mental health scores are predictive of functional outcomes in patients undergoing total knee replacement (TKR).

Researchers from the Klinik am Eichert in Goeppingen, Germany, found that low preoperative scores on the Hospital Anxiety and Depression Scale (HADS) for 60 patients who underwent TKR correlated significantly with low scores on the Knee Society Score, the Short Form (SF) Musculoskeletal Function Assessment questionnaire, and a test of self-selected walking speed (Table 1).¹ Preoperatively, 31% of the patients had increased anxiety scores and 35% had increased depression scores, said Achim Koenig, MD, a privatdocent in orthopedics at the clinic, who presented his group's results at the annual meeting of the American Academy of Orthopaedic Surgeons (AAOS) in late February.

"We used the HADS because it was specifically designed to assess anxiety and depression in the hospital and does not contain physical complaints, which could falsify psychological distress values," Koenig said.

Researchers from the University of Massachusetts Medical School in Worcester, also presenting at the AAOS meeting, found similar results by using the mental and physical component scores of the SF-36 health survey.² The University of Massachusetts study assessed 306 patients undergoing total knee or hip replacement, 55% of whom underwent TKR. About half of the patients who received hip replacement and about a third of the patients who received knee replacement had low preoperative Mental Composite Scores (MCS), but only in the TKR patients were significant differences seen between high and low MCS groups in terms of Physical Composite Scores (PCS) at 1 year (Table 2).

In a separate study of 100 recipients of TKR, the University of Massachusetts researchers determined that low MCS in 33 of the patients correlated significantly with higher scores on the Beck Depression Inventory and Spielberger Trait Anxiety Inventory scales. "The Beck Depression scores in the MCS-less-than-50 group did not reach the scores typically seen in patients treated by psychologists or psychiatrists for depression," said David C. Ayers, MD, professor and chair of orthopedics and physical rehabilitation at the university, who presented the results of both studies at the AAOS meeting. "This is a low-grade, subclinical depression."

Although it is useful to confirm the relationship between MCS and Beck Depression Inventory scores in TKR patients, orthopedic surgeons are more likely to use the former for preoperative assessments because of their familiarity with the various SF surveys and because an SF assessment can provide both physical and mental outcomes data. "SF 12 or SF 36 allows measurement of both MCS and PCS, both of which are beneficial in TKR patients. There is already a wealth of information using the MCS and PCS in TKR patients. I believe we are the first to report on Beck Depression scores in TKR patients," Ayers said.

Ayers and colleagues are currently working with the American Association of Hip and Knee Surgeons and the Orthopedic Research and Education Foundation to develop a psychosocial intervention that could be used in patients with low preoperative MCS scores. Details of this project should be available within the next year, Ayers said. *

REFERENCES

1. Koenig A, Kirschner S, Faller H. Anxiety and depression influence functional results in patients with total knee replacement. Presented at: American Academy of Orthopaedic Surgeons Annual Meeting; February 23-27, 2005; Washington, DC.

2. Ayers DC, Franklin P. Preoperative emotional health and differing effects on total knee and total hip replacement outcomes. Presented at: American Academy of Orthopaedic Surgeons Annual Meeting; February 23-27, 2005; Washington, DC.