PainSci summary of Pal 2013?This page is one of thousands in the PainScience.com bibliography. It is not a general article: it is focused on a single scientific paper, and it may provide only just enough context for the summary to make sense. Links to other papers and more general information are provided at the bottom of the page, as often as possible. ★★★☆☆3-star ratings are for typical studies with no more (or less) than the usual common problems. Ratings are a highly subjective opinion, and subject to revision at any time. If you think this paper has been incorrectly rated, please let me know.
This study reports that people with patellofemoral (kneecap) pain tend to have higher kneecaps, and in turn those with high kneecaps are less likely to slide evenly on the knee. This contradicts my bias and I’m a bit skeptical. The researchers were probably biased in the other direction, and expected to find abnormalities correlating with pain. They title and abstract seem crafted to show that the study proves that tracking is a factor in patellofemoral pain, and yet I think the data shows exactly the opposite.
Strangely, they didn’t measure all that many knees, just 52, and it’s easy to find what you expect in small batches of data. They don’t report just how much higher kneecaps were in the abstract, which would be natural to do if it were an impressive number, so I suspect it’s not an impressive number. Similarly, the prevalence of maltracking was allegedly a little higher in patients with pain (32% in vs. 27%), but the statistical significance of the difference was not reported — so it probably wasn’t significant. Furthermore, the presence of maltracking or patella alta in people with pain did not increase pain level.
Even if the correlation is real, it doesn’t tell us anything about cause (maybe misbehaving kneecaps cause pain, or maybe knee pain causes kneecaps to misbehave). Almost half their subject had no abnormalities at all, which is consistent with other studies (Herrington et al) showing that you can find a roughly even mix of abnormalities in everyone, whether they have pain or not.
original abstract†Abstracts here may not perfectly match originals, for a variety of technical and practical reasons. Some abstacts are truncated for my purposes here, if they are particularly long-winded and unhelpful. I occasionally add clarifying notes. And I make some minor corrections.
The purpose of this study is to determine if patellar maltracking is more prevalent among patellofemoral (PF) pain subjects with patella alta compared to subjects with normal patella height. We imaged 37 PF pain and 15 pain free subjects in an open-configuration magnetic resonance imaging scanner while they stood in a weightbearing posture. We measured patella height using the Caton-Deschamps, Blackburne-Peel, Insall-Salvati, Modified Insall-Salvati, and Patellotrochlear indices, and classified the subjects into patella alta and normal patella height groups. We measured patella tilt and bisect offset from oblique-axial plane images, and classified the subjects into maltracking and normal tracking groups. Patellar maltracking was more prevalent among PF pain subjects with patella alta compared to PF pain subjects with normal patella height (two-tailed Fisher's exact test, p < 0.050). Using the Caton-Deschamps index, 67% (8/12) of PF pain subjects with patella alta were maltrackers, whereas only 16% (4/25) of PF pain subjects with normal patella height were maltrackers. Patellofemoral pain subjects classified as maltrackers displayed a greater patella height compared to the pain free and PF pain subjects classified as normal trackers (two-tailed unpaired t-tests with Bonferroni correction, p < 0.017). This study adds to our understanding of PF pain in two ways-(1) we demonstrate that patellar maltracking is more prevalent in PF pain subjects with patella alta compared to subjects with normal patella height; and (2) we show greater patella height in PF pain subjects compared to pain free subjects using four indices commonly used in clinics.
- “The reliability and validity of assessing medio-lateral patellar position: a systematic review,” Toby O Smith, Leigh Davies, and Simon T Donell, Manual Therapy, 2009.
- “Patellofemoral joint kinematics in individuals with and without patellofemoral pain syndrome,” N J MacIntyre, N A Hill, R A Fellows, R E Ellis, and D R Wilson, Journal of Bone & Joint Surgery, 2006.
- “Q-angle in patellofemoral pain: relationship with dynamic knee valgus, hip abductor torque, pain and function,” Gabriel Peixoto Leão Almeida, Ana Paula de Moura Campos Carvalho E Silva, Fábio Jorge Renovato França, Maurício Oliveira Magalhães, Thomaz Nogueira Burke, and Amélia Pasqual Marques, Rev Bras Ortop, 2016.
- “Patello-femoral tracking in the weight-bearing knee: a study of asymptomatic volunteers utilising dynamic magnetic resonance imaging: a preliminary report,” S Tennant, A Williams, V Vedi, C Kinmont, W Gedroyc, and D M Hunt, Knee Surgery, Sports Traumatology, Arthroscopy, 2001.
- “Associates of physical function and pain in patients with patellofemoral pain syndrome,” Sara R Piva, G Kelley Fitzgerald, James J Irrgang, Julie M Fritz, Stephen Wisniewski, Gerald T McGinty, John D Childs, Manuel A Domenech, Scott Jones, and Anthony Delitto, Archives of Physical Medicine & Rehabilitation, 2009.
- “The role of patellar alignment and tracking in vivo: the potential mechanism of patellofemoral pain syndrome,” Chen-Yi Song, Jiu-Jenq Lin, Mei-Hwa Jan, and Yeong-Fwu Lin, Physical Therapy in Sport, 2011.
These two articles on PainScience.com cite Pal 2013 as a source:
- PS Save Yourself from Patellofemoral Pain Syndrome! — Patellofemoral pain syndrome (aka runner’s knee) explained and discussed in great detail, including every imaginable self-treatment option and all the available scientific evidence
- PS Patellofemoral Tracking Syndrome — The beating heart of the conventional wisdom about patellofemoral pain is mostly nonsense
This page is part of the PainScience BIBLIOGRAPHY, which contains plain language summaries of thousands of scientific papers & others sources. It’s like a highly specialized blog. A few highlights:
- A Bayesian model-averaged meta-analysis of the power pose effect with informed and default priors: the case of felt power. Gronau 2017 Comprehensive Results in Social Psychology.
- The neck and headaches. Bogduk 2014 Neurol Clin.
- Agreement of self-reported items and clinically assessed nerve root involvement (or sciatica) in a primary care setting. Konstantinou 2012 Eur Spine J.
- Effect of NSAIDs on Recovery From Acute Skeletal Muscle Injury: A Systematic Review and Meta-analysis. Morelli 2017 Am J Sports Med.
- Association of Spinal Manipulative Therapy With Clinical Benefit and Harm for Acute Low Back Pain: Systematic Review and Meta-analysis. Paige 2017 JAMA.