Is surgeon assessed bone quality during total knee arthroplasty a valid tool to diagnose osteoporosis?

UNLABELLED

Osteoporosis continues to have a high prevalence amongst people undergoing total knee arthroplasty (TKA). The surgeon assessed intraoperative bone quality using a visual analogue scale has a strong correlation with bone mineral density. Surgeon assessment of bone quality has a high specificity(100%) and positive predictive value(100%) in diagnosing osteoporosis and osteopenia.

BACKGROUND

Patients undergoing TKA have a high prevalence of osteoporosis. Our aim is to study (a) the correlation of intraoperative surgeon assessed bone quality with bone mineral density(BMD) as measured by dual-energy x-ray absorptiometry(DEXA) and (b) the diagnostic strength of intraoperative surgeon assessment of bone quality in diagnosing osteoporosis and osteopenia, in patients undergoing TKA.

METHODS

We prospectively recruited 31 patients undergoing TKA. Patients were classified into normal, osteopenia or osteoporosis based on preoperative DEXA. Intraoperatively, the senior surgeon by visual and tactile assessment, graded the bone quality(BQ) using a visual analogue scale(VAS) from 0 to 10, with 10 being the strongest bone. Using the VAS score, we classified patients as normal(≥ 8), osteopenia(5-7) and osteoporosis(≤ 4).

RESULTS

The Spearman's rho correlation between BMD and VAS was 0.954.(p < 0.001). VAS < 8 to diagnose osteopenia and osteoporosis had a sensitivity of 70.83%, specificity of 100%, positive predictive value of 100% and diagnostic accuracy of 77.42%(p = 0.001). VAS ≤ 4 to diagnose osteoporosis had a sensitivity of 71.43%, specificity of 100%, positive predictive value of 100% and diagnostic accuracy of 93.55%(p < 0.001).

CONCLUSION

The surgeon assessed intraoperative bone quality using a VAS during TKA has a strong correlation with the gold standard BMD as measured by DEXA scan. VAS ≤ 4 can help diagnose osteoporosis, allowing surgeons to augment implant fixation with stem and cement as well as guide osteoporosis treatment postoperatively. VAS < 8 can identify osteopenic or osteoporotic bone, thus allowing the surgeon to better identify weaker bone and help titrate implant choice.