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Updated: Jun 4, 2026
Standardized Histomorphometric Evaluation of Osteoarthritis in a Surgical Mouse Model
Published on: May 6, 2020
Postoperative changes in bone mineral density and their determinants after knee arthroplasty for osteoarthritis
Mitsuhiko Kubo1, Yuki Nosaka2, Kosuke Kumagai2
1Department of Sport and Musculoskeletal Pain Medicine, Shiga University of Medical Science, Otsu-city, Japan; Department of Orthopaedic Surgery, Jinseikai Konan Hospital, Koka-city, Japan.
Background:
A significant proportion of patients undergoing knee arthroplasty for osteoarthritis also present with comorbid osteoporosis. Pain-induced reductions in lower limb loading may contribute to decreased bone mineral density (BMD). Therefore, postoperative functional recovery may influence BMD improvement. However, data on changes in BMD and their determinants are still scarce. Thus, this study aimed to evaluate changes in general BMD and its associated factors in patients undergoing knee arthroplasty for osteoarthritis.
Methods:
Fifty patients undergoing knee arthroplasty for osteoarthritis were assessed using dual-energy X-ray absorptiometry (DXA) at the lumbar spine, bilateral total hip (TH), and femoral neck (FN) preoperatively and one year postoperatively. Serum bone turnover markers (procollagen type 1 N-terminal propeptide [P1NP] and tartrate-resistant acid phosphatase-5b [TRAP-5b]), along with age and body mass index (BMI) were also evaluated. Age, BMI, P1NP levels, TRAP-5b levels, and preoperative BMD were compared between patients with and without postoperative increases in BMD. Subsequently, univariate and multivariate regression analyses were performed to examine associations between the magnitude of BMD change at each measurement site and the aforementioned variables.
Results:
No significant changes in mean BMD were observed at any site. However, individual variations were substantial, with BMD increases observed in 34-48% of cases, depending on the site. Patients who exhibited increased BMD at the ipsilateral TH had significantly lower TRAP-5b levels (P = 0.04). Multivariate analyses revealed a moderate, significant positive correlation between BMD changes at the contralateral FN and BMI (β = 0.33, P = 0.03).
Conclusions:
The study results suggest that postoperative BMD changes vary across patients and are associated with both mechanical loading and bone turnover. Higher BMI was associated with greater BMD recovery, possibly reflecting increased mechanical loading, particularly at the contralateral limb. In contrast, lower TRAP-5b levels were associated with increased BMD at the operated limb.
