The lack of correlation between radiographic findings and cartilage integrity.

Total knee arthroplasty is a common treatment of osteoarthritis, although unicompartmental knee arthroplasties are frequently used to retain unaffected compartments. Joint space width (JSW) is a major factor in determining treatment. We examined the relationship between JSW and cartilage quality in 60 patients undergoing total knee arthroplasty to assess its accuracy in representing cartilage degradation. Radiographic JSW was recorded, whereas the unaffected compartment of each tibial plateau was examined postoperatively using Collins, Mankin, and Kellgren and Lawrence scores. No correlation was seen between visual or histologic grading and JSW. Histology more accurately represented cartilage quality, yet it is impractical to obtain preoperatively; thus, JSW is the main mode of assessment. However, using JSW solely to indicate unicompartmental knee arthroplasty may overlook disease in apparently unaffected compartments.