Limits...
Low bone mineral density is associated with the onset of spontaneous osteonecrosis of the knee.

Akamatsu Y, Mitsugi N, Hayashi T, Kobayashi H, Saito T - Acta Orthop (2012)

Bottom Line: The BMDs measured at the lumbar spine, ipsilateral femoral neck, and knee condyles and the ratios of medial condyle BMD to lateral condyle BMD (medial-lateral ratios) in the femur and tibia were compared between the two groups.The mean femoral and tibial medial-lateral ratios were statistically significantly higher in the SONK patients than in the OA patients.A proportion of women over 60 years of age have low BMD that progresses rapidly after menopause and can precipitate a microfracture.

View Article: PubMed Central - PubMed

Affiliation: Department of Orthopaedic Surgery, Yokohama City University Medical Center, Yokohama City, Kanagawa, Japan. akamatsu@yokohama-cu.ac.jp

ABSTRACT

Background and purpose: The primary event preceding the onset of symptoms in spontaneous osteonecrosis in the medial femoral condyle (SONK) may be a subchondral insufficiency fracture, which may be associated with underlying low bone mineral density (BMD). However, the pathogenesis of SONK is considered to be multifactorial. Women over 60 years of age tend to have higher incidence of SONK and low BMD. We investigated whether there may be an association between low BMD and SONK in women who are more than 60 years old.

Methods: We compared the BMD of 26 women with SONK within 3 months after the onset of symptoms to that of 26 control women with medial knee osteoarthritis (OA). All the SONK patients had typical clinical presentations and met specified criteria on MRI. The BMDs measured at the lumbar spine, ipsilateral femoral neck, and knee condyles and the ratios of medial condyle BMD to lateral condyle BMD (medial-lateral ratios) in the femur and tibia were compared between the two groups. The medial-lateral ratios were used as parameters for comparisons of the BMDs at both condyles.

Results: The mean femoral neck, lateral femoral condyle, and lateral tibial condyle BMDs were between x% and y% lower in the SONK patients than in the OA patients (p < 0.001). The mean femoral and tibial medial-lateral ratios were statistically significantly higher in the SONK patients than in the OA patients.

Interpretation: A proportion of women over 60 years of age have low BMD that progresses rapidly after menopause and can precipitate a microfracture. These findings support the subchondral insufficiency fracture theory for the onset of SONK based on low BMD.

Show MeSH

Related in: MedlinePlus

The necrotic angle (Mont et al. 2000) was measure in the sagittal plane (A) and the coronal plane (B). The 2 angles were summed to give the combined necrotic angle. In this case, the combined necrotic angle was 108° (40° + 68°).
© Copyright Policy - open-access
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC3369150&req=5

Figure 4: The necrotic angle (Mont et al. 2000) was measure in the sagittal plane (A) and the coronal plane (B). The 2 angles were summed to give the combined necrotic angle. In this case, the combined necrotic angle was 108° (40° + 68°).

Mentions: All the SONK patients had findings in the weight-bearing area on MRI. In addition, we used the necrotic angle to measure the size of the epiphyseal lesion on MRI (Mont et al. 2000). The arcs of involvement of the subchondral lesion were measured using the center of the radius of the lesion, as measured from the epiphyseal scar in the sagittal and coronal planes (Figure 4). The 2 angles were summed to give the combined necrotic angle, which was used to assess the total lesions. Lesions of 150° or less were categorized as small, lesions of 151–249° were categorized as medium, and lesions of 250° or more were categorized as large.


Low bone mineral density is associated with the onset of spontaneous osteonecrosis of the knee.

Akamatsu Y, Mitsugi N, Hayashi T, Kobayashi H, Saito T - Acta Orthop (2012)

The necrotic angle (Mont et al. 2000) was measure in the sagittal plane (A) and the coronal plane (B). The 2 angles were summed to give the combined necrotic angle. In this case, the combined necrotic angle was 108° (40° + 68°).
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3369150&req=5

Figure 4: The necrotic angle (Mont et al. 2000) was measure in the sagittal plane (A) and the coronal plane (B). The 2 angles were summed to give the combined necrotic angle. In this case, the combined necrotic angle was 108° (40° + 68°).
Mentions: All the SONK patients had findings in the weight-bearing area on MRI. In addition, we used the necrotic angle to measure the size of the epiphyseal lesion on MRI (Mont et al. 2000). The arcs of involvement of the subchondral lesion were measured using the center of the radius of the lesion, as measured from the epiphyseal scar in the sagittal and coronal planes (Figure 4). The 2 angles were summed to give the combined necrotic angle, which was used to assess the total lesions. Lesions of 150° or less were categorized as small, lesions of 151–249° were categorized as medium, and lesions of 250° or more were categorized as large.

Bottom Line: The BMDs measured at the lumbar spine, ipsilateral femoral neck, and knee condyles and the ratios of medial condyle BMD to lateral condyle BMD (medial-lateral ratios) in the femur and tibia were compared between the two groups.The mean femoral and tibial medial-lateral ratios were statistically significantly higher in the SONK patients than in the OA patients.A proportion of women over 60 years of age have low BMD that progresses rapidly after menopause and can precipitate a microfracture.

View Article: PubMed Central - PubMed

Affiliation: Department of Orthopaedic Surgery, Yokohama City University Medical Center, Yokohama City, Kanagawa, Japan. akamatsu@yokohama-cu.ac.jp

ABSTRACT

Background and purpose: The primary event preceding the onset of symptoms in spontaneous osteonecrosis in the medial femoral condyle (SONK) may be a subchondral insufficiency fracture, which may be associated with underlying low bone mineral density (BMD). However, the pathogenesis of SONK is considered to be multifactorial. Women over 60 years of age tend to have higher incidence of SONK and low BMD. We investigated whether there may be an association between low BMD and SONK in women who are more than 60 years old.

Methods: We compared the BMD of 26 women with SONK within 3 months after the onset of symptoms to that of 26 control women with medial knee osteoarthritis (OA). All the SONK patients had typical clinical presentations and met specified criteria on MRI. The BMDs measured at the lumbar spine, ipsilateral femoral neck, and knee condyles and the ratios of medial condyle BMD to lateral condyle BMD (medial-lateral ratios) in the femur and tibia were compared between the two groups. The medial-lateral ratios were used as parameters for comparisons of the BMDs at both condyles.

Results: The mean femoral neck, lateral femoral condyle, and lateral tibial condyle BMDs were between x% and y% lower in the SONK patients than in the OA patients (p < 0.001). The mean femoral and tibial medial-lateral ratios were statistically significantly higher in the SONK patients than in the OA patients.

Interpretation: A proportion of women over 60 years of age have low BMD that progresses rapidly after menopause and can precipitate a microfracture. These findings support the subchondral insufficiency fracture theory for the onset of SONK based on low BMD.

Show MeSH
Related in: MedlinePlus