Vol.:(0123456789) 1 3 Knee Surgery, Sports Traumatology, Arthroscopy https://doi.org/10.1007/s00167-018-5043-y KNEE High heterogeneity in in vivo instrumented-assisted patellofemoral joint stress testing: a systematic review Ana Leal 1,2  · Renato Andrade 2,3,4  · Paulo Flores 1  · Filipe Samuel Silva 1  · João Espregueira‑Mendes 2,3,5,6,7  · Elizabeth Arendt 8,9 Received: 20 April 2018 / Accepted: 26 June 2018 © European Society of Sports Traumatology, Knee Surgery, Arthroscopy (ESSKA) 2018 Abstract Purpose Summarize the in vivo instrumented-assisted patellofemoral evaluation methods for quantifying the patellar mobil- ity in response to a known external force. Methods A systematic review using PubMed, EMBASE, Cochrane Library, and SPORTDiscus electronic databases was con- ducted to search for studies reporting in vivo instrumented-assisted patellofemoral evaluation of patellar mobility. Searches were conducted in duplicate up to October 2017. Methodologic quality of included articles was assessed using a modifed version of the Critical Appraisal Skills Program (CASP) critical appraisal tool. Results From the original 2614 records, 9 studies comprising 568 individuals (24 ± 4.8 years old, 51.4% females)—355 (62.5%) asymptomatic individuals, 87 (15.3%) patellofemoral pain, and 126 (22.2%) patellofemoral instability patients—were included. The average maximum force applied by the instruments to the patella was 38.9 ± 27.7 N (range 11.25 to 80 N). Patellar displacement ranged from 3.9 to 10.4 mm, medially, and 3.5 to 14.8 mm, laterally, for asymptomatic individuals. For patellofemoral instability patients, these values were higher, ranging from 3.8 to 22.1 mm, medially, and 7.0 to 21.9 mm, laterally, being these mean values similar across the instability subgroups (medial, lateral, or multidirectional). Patellofemoral pain had a mean of 10 mm and 10.9 mm for medial and lateral displacements, respectively. Mean methodological quality score was 9.8 ± 2.6 (range 6–13) out of 18 possible points. Conclusions There is high heterogeneity within the available instrumented assessment methods and respective measure- ment outcomes, highlighting the need for better methodological standardization and further developments in this feld. This would allow a more accurate and reliable quantifcation of patellar movement and, subsequently, improve diagnosis, and refne treatment. Level of evidence Systematic review of level II–IV studies, Level IV Introduction Patellofemoral (PF) joint instability is complex and mul- tifactorial, posing a clinical challenge in its diagnosis and management. Part of this complexity relates to the patella being a part of a dynamic system, the extensor mechanism, and as such ofers limitations to in vitro testing. The diagno- sis of PF instability is based on the patient’s symptomatol- ogy, physical examination of the knee and lower limb, and an array of imaging fndings [13, 16]. The imaging fndings have played a crucial role in identifying potential anatomi- cal and morphological factors that are associated with an increased risk for patellar instability [2, 3, 6, 29]. The physi- cal examination of the PF joint provides important informa- tion regarding the PF clinical and biomechanical statuses, which details a more qualitative assessment rather than a quantitative measurement. Furthermore, this examination is performed manually which, despite the reasonable intra- tester reliability, lacks precision (objective quantifcation), inter-tester reliability, and reproducibility [24, 25]. Hence, these are not suitable for universal application, which may lead to misdiagnosis, poor prognostic value of the available therapeutic, or preventive strategies, and even lead to unnec- essary and/or inadequate interventions [1]. Electronic supplementary material The online version of this article (https://doi.org/10.1007/s00167-018-5043-y) contains supplementary material, which is available to authorized users. * João Espregueira-Mendes espregueira@dhresearchcentre.com Extended author information available on the last page of the article