Evidence-based medicine: Strike a balance between lab findings, patient evaluations

Issue: Issue 5 2006

René Verdonk, MD, PhD [photo]
René Verdonk

Have we heard this message before?

I saw Paul last year. It had been 18 years since my colleagues and I replaced the medial compartment in his right knee. It had evolved satisfactorily, as I had seen him for follow-up every year since. There was good function … a stable knee joint.

I had Paul fill out our follow-up sheets like the Hospital for Special Surgery Knee Test, the SF-36, and other forms. He rated high. He showed good imaging over the years, even though he had seen several radiologists since he had moved. Some came to us with excellent reports, while others cited loosening lines.

Just recently, I read a report that said, “Right knee: to be compared” (to earlier documents, I suppose). In fact, I rarely look at these comments, but something made me think, “Should I?”

New developments

Paul called because he had experienced sudden problems in his right knee. Nothing obvious had gone wrong — no trauma, no overuse — just a sudden onset of pain, swelling and locking. Yet it was clear that something was wrong. Although Paul could walk without crutches, he felt invalidating peak stress pain when he was weight-bearing.

His X-rays showed the usual wear and tear, although I kept focusing on this loosening line, which had always been present and had not changed over the years. It is the kind that one often sees but does not correlate with the clinical findings. Nothing else seemed to be wrong.

Because the bone scan did not offer much help, a CT scan concerned me even more and required appropriate attention. Rest and the “classic recommendations” had not brought any improvement, and Paul required quick relief. I was urged to do something, and we decided to go to surgery.

Indeed, the medial condylar implant was not wobbling but showed clear loosening; we could revise the single implant. We saw no obvious wear on the PE implant but we changed it for safety’s sake. Today, all is going well again.

Survival curves

Paul’s case can be documented, reviewed and controlled via many scores — both clinically and by imaging — as well as by other validated scoring systems. It also helps to set up survival curves, which can warn the orthopaedic community about implants we use over time. We all agree on this.

Recently, I joined an upscale prospective study on cartilage transplantation. There had been an excellent setup, selection of cases, and agreement by ethical committees. I was proud to have participated. Personal evaluation patients in the studyhad been highly stimulating, but of course we needed objective findings, such as biopsies and MR imaging.

The findings stunned us. The experts could not agree on a conclusion about what had been retrieved as illustrated both under the microscope and on the screen. What is normal and what is abnormal? What was hyaline or fibrocartilage? What was necrotic and what appeared to be living tissues?

On the horizon

Frankly, I am concerned. It is clear we need more evidence to further our understanding, but are laboratory evidence and biopsy protocols the only truth on which we can rely? Are good individual patient scores and validated clinical findings unreliable?

I look forward to the day when we place equal importance on objective findings (if conclusive) and patient evaluation scores in planning our day-by-day patient care. I realize that the regulatory groups are considering this even more now.

Have we heard this before?

For more information:
René Verdonk, MD, PhD, is chair of the department of orthopaedic surgery at Ghent University Hospital in Belgium and is an editor of Orthopaedics Today.