Osteoarthritis (OA) is the most chronic joint disorder with an estimated prevalence of 15% worldwide, mainly affecting population aged between 56 to 84.
Radiographic findings including joint
space narrowing and MRI detected bone marrow lesions, synovitis and effusion are
significantly associated with the long term risk of total
knee arthroplasty (TKA) in knee osteoarthritis patients.
Osteoarthritis (OA) is the most chronic joint disorder with
an estimated prevalence of 15% worldwide, mainly affecting population aged
between 56 to 84. Previous studies reported that aging and obesity were
strongly associated with OA.
Obesity is known to be an essential risk factor for knee OA.
A recent systematic review showed that 25% cases of knee pain were associated
with overweight and obesity and only 5% were caused due to any previous knee
injury. At the end stage of OA, total knee arthroplasty (TKA) is the only
effective treatment. A recent study conducted by Weinstein et al
determined that 52% of patients with knee OA are likely to undergo TKA. For
imaging of knee OA, the conventional radiography is the most commonly used
method. But the results of this method are not well correlated with symptoms.
Magnetic resonance imaging (MRI) offers the ability to visualize all structures
in and around the knee, including cartilage, subchondral bone and soft tissue.
Specific pathologic findings on MRI, including bone marrow lesions (BMLs) and
synovitis, are moderately correlated with pain and are associated with risk of
TKA in studies with short-term follow-up as well as with progression of Joint space
narrowing (JSN).
Therefore, this study was conducted to analyze whether
clinical, radiographic and MRI findings, including Bone marrow lesion (BML) and
synovitis, correlate with the incidence of TKA during a mean follow-up period
of 15 years.
Rationale behind the research:
None of the studies till now analyze the finding of radiographic, MRI with the incidence of TKA. Therefore, in this study the impact of these finding on the TKA were analysed.
Objective:
To evaluate the link between clinical,
radiographic or MRI findings and long-term risk for TKA in persons with knee
osteoarthritis.
Study outcome measures:
Clinical, radiographic and MRI findings were analyzed
for associations with subsequent TKA.
Study Outcomes:
Figure 1: Kaplan-Meier plot showing the cumulative incidence of TKA in relation to different degrees of JSN, BML, synovitis and effusion
Cox proportional hazard ratio showed a statistically significant hazard ratio for JSN, radiological sum score, BML, synovitis and effusion with the risk for TKA.
The 66 participants with TKA at follow-up were compared in relation to
unilateral versus bilateral TKA; only BMI was associated with the risk of
bilateral vs. unilateral TKA (OR 2.3 (95% CI 1.2 – 4.3))
The results of this study revealed that after the 15
years of follow-up study the radiographic findings, precisely the degree of
JSN, and MRI detected BML, synovitis, and effusion were highly associated with
TKA.
According to the Danish national guidelines, the
indications for TKA are based on symptoms and objective findings. It is,
however, without the radiographic images of OA, especially JSN, the surgeon
would not operate on a knee. Thus, a relative contra-indication for TKA is
absence of or minimal radiologic changes. Previous studies showed that JSN has
also be associated with the progression of knee OA. Two studies conducted by
Oak et al and Raynauld et al also showed the significant relation
of JSN with worsening of knee OA.
The number of previous studies showed the significant
association of BML, synovitis, and effusion with the risk of TKA. However, these
studies had a relatively short follow-up time. The results of this study also
showed similar results as of previous studies with long-term risk of TKA. This study
showed that long-term risk of TKA was dependent on the number of structural
changes on radiographs and signs of synovial inflammation or BMLs on MR images.
No significant association was found between baseline
BMI and TKA. Thus, the results suggest that a higher BMI does not increase the
risk of TKA in knees with symptomatic OA. However, it seems that an increased
BMI predisposes to the development of OA in the opposite knee. Other studies
have similarly reported that an elevated BMI influences the incident but not
the progression of knee OA.
In conclusion, radiographic changes associated with knee
OA as well as MRI detected BMLs, synovitis, and effusion were significantly
related to the risk of TKA in patients with knee OA. However, an increased BMI
was seen in participants with knee OA requiring TKA in the opposite knee during
follow-up.
BMC Musculoskelet Disord. 2017; 18: 510.
Risk factors for joint replacement in knee osteoarthritis; a 15-year follow-up study
Flemming K. Nielsen et al.
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