In the JournalsPerspective

Radiographic patellofemoral OA correlates with anterior knee pain

According to recently published results, patellofemoral alignment and trochlear morphology correlated with anterior knee pain in patients with or at risk for knee osteoarthritis. Radiographic patellofemoral osteoarthritis was correlated with pain, which demonstrates signs of osteoarthritis and may lead to localized symptoms.

In the Multicenter Osteoarthritis Study, investigators evaluated 3,026 patients with, or at risk for, knee osteoarthritis (OA). They assessed patients for cross-sectional associations of patellofemoral alignment, trochlear morphology and patellofemoral and tibiofemoral radiographic OA, with localized anterior knee pain. The two approaches used included a withinperson kneematched evaluation of 110 patients with unilateral anterior knee pain and a cohort approach that compared 1,818 patients with and without anterior knee pain.

Results from the within-person knee-matched approach showed there was no association between patellofemoral alignment, morphology and tibiofemoral OA and unilateral anterior knee pain. The chance for a patient to have anterior knee pain was increased in patients with radiographic patellofemoral OA compared with patients without (OR = 5.3). A greater prevalence of anterior pain correlated with radiographic patellofemoral OA (prevalence ratio = 2.2). – by Monica Jaramillo

 

Disclosures: The researchers report no relevant financial disclosures.

 

 

According to recently published results, patellofemoral alignment and trochlear morphology correlated with anterior knee pain in patients with or at risk for knee osteoarthritis. Radiographic patellofemoral osteoarthritis was correlated with pain, which demonstrates signs of osteoarthritis and may lead to localized symptoms.

In the Multicenter Osteoarthritis Study, investigators evaluated 3,026 patients with, or at risk for, knee osteoarthritis (OA). They assessed patients for cross-sectional associations of patellofemoral alignment, trochlear morphology and patellofemoral and tibiofemoral radiographic OA, with localized anterior knee pain. The two approaches used included a withinperson kneematched evaluation of 110 patients with unilateral anterior knee pain and a cohort approach that compared 1,818 patients with and without anterior knee pain.

Results from the within-person knee-matched approach showed there was no association between patellofemoral alignment, morphology and tibiofemoral OA and unilateral anterior knee pain. The chance for a patient to have anterior knee pain was increased in patients with radiographic patellofemoral OA compared with patients without (OR = 5.3). A greater prevalence of anterior pain correlated with radiographic patellofemoral OA (prevalence ratio = 2.2). – by Monica Jaramillo

 

Disclosures: The researchers report no relevant financial disclosures.

 

 

    Perspective
    Matthew Bollier

    Matthew Bollier

    The etiology of anterior knee pain has befuddled knee surgeons for years. Many theories have been proposed and studied without a clear explanation.

    This paper examined an older cohort who had risk factors for arthritis. Patellofemoral arthritis was linked to anterior knee pain, while patellofemoral alignment and morphology were not. This is consistent with my clinical observations. We still do not understand why some patients with abnormal morphology and alignment have anterior knee pain, and others do not. The development of radiographic signs of patellofemoral arthritis is clearly associated with anterior knee pain. Limitations of this paper include patients older than 50 years (most of my anterior knee pain patients are 15- to 40-years old) and not examining patella cartilage status.

    • Matthew Bollier , MD, FAOA
    • Ralph and Marcia Congdon Professor in Orthopedic Surgery
      Sports medicine fellowship director, team physician
      University of Iowa Hospitals and Clinics
      Iowa City, Iowa

    Disclosures: Bollier reports no relevant financial disclosures.

    Perspective
    Jack Farr

    Jack Farr

    Marcri and colleagues evaluated the effect of trochlear morphology and patellofemoral (PF) alignment on anterior knee pain in their study, “Relation of patellofemoral joint alignment, morphology, and radiographic osteoarthritis to frequent anterior knee pain: The MOST Study.” They obtained imaging from the multicenter osteoarthritis study (MOST) cohort and used two data analysis approaches: a within-person knee-matched evaluation of 110 patients aged 50 to 79 years with unilateral anterior knee pain (AKP) (conditional logistic regression); and a cohort approach comparing 58 patients with AKP to those 824 (again ages 50 to 79 years) without frequent AKP (binomial regression).

    They did not find a relationship between AKP and trochlear morphology, patellar alignment or tibiofemoral (TF) osteoarthritis (OA). This did show a positive relationship between patellofemoral OA and AKP. From a clinical perspective, I agree that nonarthritic trochlear dysplasia and TF OA are not associated with AKP and PF OA is associated with AKP. Trochlear dysplasia is associated with patellar instability in the younger patient and is associated with future PF OA risk.

    On the other hand, the finding that patellofemoral “malalignment” is not associated with AKP is counterintuitive to what many PF specialists would offer. Many factors could contribute to this discrepancy. 

    1) AKP outside of PF OA is most often encountered in those younger than 50 years and study patients were 50 to 79 years.

    2) Seventy-nine-year-old patients often have general health conditions that lead to more sedentary activities than the younger population. That is, they may not use stairs or steps as frequently and may not load the PF compartment sufficiently to tease out the differences between normal and malalignment. Even advanced PF OA patients do acceptably well on level ground.

    3) We do not know the genetics of the patients. Some patients with “poor cartilage genetics” and patellar malalignment often present with PF OA in the age group of 40 to 60 years. Thus, those patients would have crossed over to PF OA cohort before inclusion in the study.

    I agree with the authors that a larger study is warranted and would add patients of all ages.

    • Jack Farr, MD
    • Knee preservation and cartilage restoration,
      Ortho Indy
      Indianapolis, Indiana

    Disclosures: Farr reports no relevant financial disclosures.

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