Study examines impact of preoperative functional status on postoperative outcomes
Research presented at the American Association of Hip and Knee Surgeons (AAHKS) annual meeting indicates that total joint arthroplasty (TJA) patients with lower preoperative function have worse mid- to long-term outcomes than patients with higher preoperative function.

According to Carlos J. Lavernia, MD, who presented the study, the findings suggest that timing of surgery may be an important consideration in patients undergoing TJA.

Retrospective review of prospectively collected data
Earlier research conducted by Dr. Lavernia and colleagues demonstrated that in the short term, TJA patients with lower preoperative function had worse self-reported outcomes than patients with higher preoperative function. In this study, the researchers reviewed data on a subset of 105 patients from the original cohort to evaluate mid- to long-term outcomes.

Among the 105 patients (mean age: 65 years), 54 patients had undergone total hip arthroplasty (THA) and 51 patients had undergone total knee arthroplasty (TKA) for osteoarthritis (OA) after conservative treatment had failed. A single surgeon performed all surgeries. Western Ontario and McMaster Osteoarthritis Index (WOMAC), Short Form 36 (SF-36), and Quality of Well Being Scale (QWB-7) scores were obtained from all patients pre- and postoperatively. Overall patient satisfaction with the surgery was also recorded.

Based on preoperative WOMAC scores, the researchers divided the patients into the following two groups:

• Severely functionally impaired (WOMAC ≥ 51; n = 31; 40 percent female)
• Functionally impaired (WOMAC > 51; n = 74; 73.8 percent female)

Aside from the significant difference between the groups with respect to sex, baseline patient demographics were similar.

Analyzing the data
The researchers used multivariate analysis to assess differences in pre- and postoperative scores and pre- to postoperative changes in scores between the two groups. The average postoperative follow-up for all patients was 11.2 years (range: 3–21 years). Overall, 13 patients had undergone revision surgery and 43 patients had died at an average of 10 years and 12 years, respectively. The researchers found no significant differences in revision or mortality rates between the two groups.

Preoperatively, all scores were significantly worse for the severely functionally impaired group than for the functionally impaired group.

Postoperative data were evaluated and changes in scores were calculated only for patients who had not undergone revision surgery. Although function scores had improved in both groups, they were still worse for patients with severely impaired preoperative function, with most differences reaching statistical significance (Table 1). Patient satisfaction was also slightly diminished among patients with lower preoperative function, compared to those with higher preoperative function (92 percent versus 98 percent, respectively).

Although the severely functionally impaired patients showed a significantly greater improvement in pre- to postoperative WOMAC scores (P ≤ 0.025), these patients did not do as well overall as patients who were only functionally impaired preoperatively, noted Dr. Lavernia. The pre- to postoperative changes in all SF-36 and QWB-7 scores were not statistically significant between the groups.

The researchers concluded that in the mid- to long term, patients who underwent THA or TKA with severe preoperative functional impairment continue to have worse outcomes than patients with less severe preoperative functional impairment.

"All patients benefited from their surgery; however, we found that those who allowed their function to deteriorate significantly before undergoing TJA did not fully 'catch up' to patients who underwent surgery at an earlier disease stage," said Dr. Lavernia. "The results of our study indicate that OA patients may experience better overall results if they undergo surgical intervention before the disease severely limits their mobility."

Dr. Lavernia's coauthors of "Prolonged Conservative Management in Total Joint Arthroplasty: Harming the Patient?" are Anneliese D. Heiner, PhD; Michael Cronin, DO; and Mark D. Rossi, PhD.

The authors' disclosure information can be accessed at www.aaos.org/disclosure

Maureen Leahy is assistant managing editor of AAOS Now. She can be reached at leahy@aaos.org

Bottom Line

• This study compared mid- to long-term patient-reported outcomes of TJA patients with severe versus less severe preoperative functional impairment.
• The researchers found that patients who were severely functionally impaired had worse outcomes after surgery than those who were less severely impaired.
• The results suggest that delaying surgery may be detrimental to patients with severely impaired preoperative function.

Reference:
http://www.arthroplastyjournal.org/article/S0883-5403(08)00771-7/abstract