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Distal femoral bone mineral density decreases following patellofemoral arthroplasty: 1-year follow-up study of 14 patients.

van Jonbergen HP, Koster K, Labey L, Innocenti B, van Kampen A - BMC Musculoskelet Disord (2010)

Bottom Line: The bone mineral density (BMD) of the distal femur decreases by 16-36% within one year after total knee arthroplasty (TKA) because of the femoral component's stress-shielding effect.The mean change from baseline BMD in the operated knees after 1 year was -0.169 g/cm2 (95% CI: -0.293 to -0.046 g/cm2) behind the anterior flange (-15%), and -0.076 g/cm2 (95% CI: -0.177 to 0.024 g/cm2) in the supracondylar area 1 cm above the prosthesis (-8%) (p = 0.01 and p = 0.13, respectively).The mean change from baseline BMD in the non-operated knees after 1 year was 0.016 g/cm2 (95% CI: -0.152 to 0.185 g/cm2) behind the anterior flange (2%), and 0.023 g/cm2 (95% CI: -0.135 to 0.180 g/cm2) in the supracondylar area 1 cm above the prosthesis (2%) (p = 0.83, and p = 0.76, respectively).

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Affiliation: Department of Orthopedic Surgery, Deventer Hospital, Nico Bolkesteinlaan 75, 7416 SE Deventer, The Netherlands. vanjonbergen@dz.nl

ABSTRACT

Background: The bone mineral density (BMD) of the distal femur decreases by 16-36% within one year after total knee arthroplasty (TKA) because of the femoral component's stress-shielding effect. The aim of this prospective study was to determine the quantitative change from the baseline BMD in the distal femur 1 year after patellofemoral arthroplasty using dual-energy X-ray absorptiometry (DXA).

Methods: Between December 2007 and December 2008, 14 patients had patellofemoral arthroplasty for isolated patellofemoral osteoarthritis. Distal femoral BMD was assessed using DXA in 2 regions of interest (ROI) on the lateral view 2 weeks before and 12 months after patellofemoral arthroplasty. The contra-lateral knee was used as a control, with BMD measurements performed in identical ROIs.

Results: The mean change from baseline BMD in the operated knees after 1 year was -0.169 g/cm2 (95% CI: -0.293 to -0.046 g/cm2) behind the anterior flange (-15%), and -0.076 g/cm2 (95% CI: -0.177 to 0.024 g/cm2) in the supracondylar area 1 cm above the prosthesis (-8%) (p = 0.01 and p = 0.13, respectively). The mean change from baseline BMD in the non-operated knees after 1 year was 0.016 g/cm2 (95% CI: -0.152 to 0.185 g/cm2) behind the anterior flange (2%), and 0.023 g/cm2 (95% CI: -0.135 to 0.180 g/cm2) in the supracondylar area 1 cm above the prosthesis (2%) (p = 0.83, and p = 0.76, respectively).

Conclusions: Our findings suggest that patellofemoral arthroplasty results in a statistically significant decrease in BMD behind the anterior flange.

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Lateral (left) and anteroposterior (right) radiographs of a right knee one year after patellofemoral arthroplasty.
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Figure 2: Lateral (left) and anteroposterior (right) radiographs of a right knee one year after patellofemoral arthroplasty.

Mentions: All patients had regular clinical follow-ups at 2 and 8 weeks to evaluate wound healing and rehabilitation, DXA was not performed at these follow-up visits. At the 1-year follow-up, patients were clinically assessed using the KSKS and KSFS, and were asked to complete the WOMAC questionnaire. During follow-up, the radiological examinations consisted of 2 radiographs (anteroposterior standing and lateral non-weight bearing) performed 6 weeks and one year post surgery (Figure 2). Radiological findings were reported using the Knee Society total knee arthroplasty roentgenographic evaluation and scoring system [12].


Distal femoral bone mineral density decreases following patellofemoral arthroplasty: 1-year follow-up study of 14 patients.

van Jonbergen HP, Koster K, Labey L, Innocenti B, van Kampen A - BMC Musculoskelet Disord (2010)

Lateral (left) and anteroposterior (right) radiographs of a right knee one year after patellofemoral arthroplasty.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC2864205&req=5

Figure 2: Lateral (left) and anteroposterior (right) radiographs of a right knee one year after patellofemoral arthroplasty.
Mentions: All patients had regular clinical follow-ups at 2 and 8 weeks to evaluate wound healing and rehabilitation, DXA was not performed at these follow-up visits. At the 1-year follow-up, patients were clinically assessed using the KSKS and KSFS, and were asked to complete the WOMAC questionnaire. During follow-up, the radiological examinations consisted of 2 radiographs (anteroposterior standing and lateral non-weight bearing) performed 6 weeks and one year post surgery (Figure 2). Radiological findings were reported using the Knee Society total knee arthroplasty roentgenographic evaluation and scoring system [12].

Bottom Line: The bone mineral density (BMD) of the distal femur decreases by 16-36% within one year after total knee arthroplasty (TKA) because of the femoral component's stress-shielding effect.The mean change from baseline BMD in the operated knees after 1 year was -0.169 g/cm2 (95% CI: -0.293 to -0.046 g/cm2) behind the anterior flange (-15%), and -0.076 g/cm2 (95% CI: -0.177 to 0.024 g/cm2) in the supracondylar area 1 cm above the prosthesis (-8%) (p = 0.01 and p = 0.13, respectively).The mean change from baseline BMD in the non-operated knees after 1 year was 0.016 g/cm2 (95% CI: -0.152 to 0.185 g/cm2) behind the anterior flange (2%), and 0.023 g/cm2 (95% CI: -0.135 to 0.180 g/cm2) in the supracondylar area 1 cm above the prosthesis (2%) (p = 0.83, and p = 0.76, respectively).

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Orthopedic Surgery, Deventer Hospital, Nico Bolkesteinlaan 75, 7416 SE Deventer, The Netherlands. vanjonbergen@dz.nl

ABSTRACT

Background: The bone mineral density (BMD) of the distal femur decreases by 16-36% within one year after total knee arthroplasty (TKA) because of the femoral component's stress-shielding effect. The aim of this prospective study was to determine the quantitative change from the baseline BMD in the distal femur 1 year after patellofemoral arthroplasty using dual-energy X-ray absorptiometry (DXA).

Methods: Between December 2007 and December 2008, 14 patients had patellofemoral arthroplasty for isolated patellofemoral osteoarthritis. Distal femoral BMD was assessed using DXA in 2 regions of interest (ROI) on the lateral view 2 weeks before and 12 months after patellofemoral arthroplasty. The contra-lateral knee was used as a control, with BMD measurements performed in identical ROIs.

Results: The mean change from baseline BMD in the operated knees after 1 year was -0.169 g/cm2 (95% CI: -0.293 to -0.046 g/cm2) behind the anterior flange (-15%), and -0.076 g/cm2 (95% CI: -0.177 to 0.024 g/cm2) in the supracondylar area 1 cm above the prosthesis (-8%) (p = 0.01 and p = 0.13, respectively). The mean change from baseline BMD in the non-operated knees after 1 year was 0.016 g/cm2 (95% CI: -0.152 to 0.185 g/cm2) behind the anterior flange (2%), and 0.023 g/cm2 (95% CI: -0.135 to 0.180 g/cm2) in the supracondylar area 1 cm above the prosthesis (2%) (p = 0.83, and p = 0.76, respectively).

Conclusions: Our findings suggest that patellofemoral arthroplasty results in a statistically significant decrease in BMD behind the anterior flange.

Show MeSH
Related in: MedlinePlus