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Knee pain linked with increased patellar lateral position after displacement

According to study results, there was a statistically significant increase in the patellar lateral position after stressed lateral displacement of the painful knee in patients with idiopathic unilateral anterior knee pain.

Researchers identified 23 patients with unilateral anterior knee pain. Conventional imaging, which included measurement of the trochlear sulcus angle, Caton-Deschamps index, tibial tuberosity to trochlear-groove distance, patellar tilt angle and patellar subluxation, was used to examine both knees of all patients. All patients also underwent stress testing with the Porto Patella Testing Device. A physical examination, Kujala score and Lysholm score were used to obtain clinical and functional outcomes.

Results showed painful knees had a significantly higher patellar lateral position after stressed lateral translation compared with non-painful knees (9.8 mm vs. 7.1 mm). The patellar position after lateral displacement significantly correlated with anterior knee pain, according to results of an adjusted multivariate logistic model. The model also demonstrated a reasonable sensitivity of 67% and specificity of 73%. – by Monica Jaramillo

 

Disclosures: The researchers report no relevant financial disclosures.

According to study results, there was a statistically significant increase in the patellar lateral position after stressed lateral displacement of the painful knee in patients with idiopathic unilateral anterior knee pain.

Researchers identified 23 patients with unilateral anterior knee pain. Conventional imaging, which included measurement of the trochlear sulcus angle, Caton-Deschamps index, tibial tuberosity to trochlear-groove distance, patellar tilt angle and patellar subluxation, was used to examine both knees of all patients. All patients also underwent stress testing with the Porto Patella Testing Device. A physical examination, Kujala score and Lysholm score were used to obtain clinical and functional outcomes.

Results showed painful knees had a significantly higher patellar lateral position after stressed lateral translation compared with non-painful knees (9.8 mm vs. 7.1 mm). The patellar position after lateral displacement significantly correlated with anterior knee pain, according to results of an adjusted multivariate logistic model. The model also demonstrated a reasonable sensitivity of 67% and specificity of 73%. – by Monica Jaramillo

 

Disclosures: The researchers report no relevant financial disclosures.

    Perspective
    Michael J. Alaia

    Michael J. Alaia

    Anterior knee pain is one of the most common complaints fielded by sports medicine physicians and surgeons. The well-conducted study “Unilateral anterior knee pain is associated with increased patellar lateral position after stressed lateral translation” by Leal and colleagues attempts to correlate increased patellar mobility with isolated, unilateral anterior knee pain. Twenty-three patients presenting to their clinic, assuming no significant radiographic parameters of patellofemoral instability or clinical/radiologic manifestations of ligamentous or meniscal injury or osteoarthritis, underwent a full clinical evaluation and completed Porto Patella Testing Device (PPTD) examinations with non-weight-bearing MRI/CT testing. The PPTD allows radiographic measurements of lateral translation, as well as patellar tilt, by applying stress to a relaxed patella in different angles and direction.

    The authors found significant increases in lateral translation under applied medial stress compared to the contralateral, asymptomatic knee (9.8 +/- 3.6 mm and 7.1 +/- 6.3 mm, respectively, P = .028). These results may shed more light into the Pandora’s box that is anterior knee pain and confirm that our clinical examinations are likely not sensitive enough to appreciate these subtle differences in patellar translation. However, it still remains unknown if this small difference in non-weight-bearing patellar translation has any bearing on long-term outcome or response (or lack thereof) to a focused course of nonoperative management.

     

    Reference:

    Leal A, et al. Knee Surg Sports Traumatol Arthrosc. 2019;doi:10.1007/s00167-019-05601-4.

     

    • Michael J. Alaia, MD
    • Assistant professor of orthopedic surgery
      Associate director, Sports Medicine Fellowship
      Division of Sports Medicine
      NYU Langone Medical Center
      New York

    Disclosures: Alaia reports no relevant financial disclosures.

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