title: Outcome predictors for conservative patellofemoral pain management: a systematic review and meta-analysis.
abstract: BACKGROUND
  Patellofemoral pain (PFP) is highly prevalent within both sporting and recreationally active populations. Multiple treatment approaches have been advocated for the management of PFP, attempting to address both intrinsic and extrinsic factors thought to contribute to the development and persistence of pain. A number of predictors of treatment success have been proposed, and evaluated, for directing intervention choice.
  
  
  OBJECTIVE
  Our aim was to systematically review the literature that identifies outcome predictors of specific conservative interventions in the management of PFP, including quality of the current evidence, to guide clinical practice and future studies investigating outcome predictors within this population.
  
  
  METHODS
  The AMED, CINAHL, EMBASE, MEDLINE and Web of Science databases were searched from inception to April 2013.
  
  
  METHODS
  Randomized controlled trials (RCTs) and cohort studies.
  
  
  METHODS
  Following initial searching, all potential papers were assessed by two independent reviewers for inclusion using a checklist developed from the inclusion criteria. Cited, and citing, references were also searched in Google Scholar, but unpublished work was not sought. Methodological quality was assessed using a previously designed quality assessment scale. Definitions for levels of evidence were guided by recommendations made by van Tulder et al.
  
  
  RESULTS
  Fifteen low-quality (LQ) cohort studies were included. No RCTs were found. This systematic review identified the evaluation of 205 conservative management outcome predictor variables. Of this large number of variables that have been assessed, 19 (9%) were found to significantly predict a successful outcome. Where two or more outcome predictors and success determinants were consistent between studies, data were pooled. Within these studies, the low number of participants per output variable, and absence of controls, is likely to compromise the validity of the predictor's accuracy. Very limited evidence identified higher functional index questionnaire scores (mean 0.82, 95% confidence interval [CI] 0.18-1.46), greater forefoot valgus (mean 0.67, 95% CI 0.05-1.28) and greater rearfoot eversion magnitude peak (mean -0.93, 95% CI -1.84 to -0.01) to significantly predict improved outcomes with orthoses interventions. Shorter symptom duration (p = 0.019), lower frequency of pain (p = 0.012), younger age, faster vastus medialis oblique reflex response time (p = 0.026), negative patella apprehension, absence of chondromalacia patella, tibial tubercle deviation of <14.6 mm and greater total quadriceps cross-sectional area on magnetic resonance imaging (p = 0.01), and reduced eccentric average quadriceps peak torque (p = 0.015) significantly predicted exercise intervention success following multivariate statistical analysis. Limited evidence identified increased Q-angle (mean 0.38, 95% CI 0.05-0.72) and very limited evidence identified greater usual pain (mean 0.43, 95% CI 0.01-0.85) to predict taping intervention success.
  
  
  CONCLUSIONS
  This systematic review provides a comprehensive summary of current derivation level studies identifying indicators of prediction for conservative PFP management. The overall strength of evidence was low. With appropriate caution, clinicians should consider taping for those with greater usual pain, orthoses for older individuals and exercise for younger individuals, and orthoses intervention for patients with greater forefoot valgus and rearfoot eversion magnitude peak. RCTs with evaluation of outcome prediction as a primary aim are clearly warranted to provide clinicians with robust evidence and facilitate evidence-informed, tailored intervention to this heterogeneous patient population.
authors.affiliation: Centre for Sports and Exercise Medicine, William Harvey Research Institute, Bart's and the London School of Medicine and Dentistry, Queen Mary University of London, Mile End Hospital, Bancroft Road, London, E1 4DG, UK.
authors.forename: Simon
authors.initials: S
authors.lastname: Lack
authors.forename: Christian
authors.initials: C
authors.lastname: Barton
authors.forename: Bill
authors.initials: B
authors.lastname: Vicenzino
authors.forename: Dylan
authors.initials: D
authors.lastname: Morrissey
mesh_terms: D000894:Anti-Inflammatory Agents, Non-Steroidal / Q000627:therapeutic use; D006801:Humans; D009989:Orthotic Devices; D059408:Pain Management / Q000379:methods*; D046788:Patellofemoral Pain Syndrome / Q000628:therapy*; D026741:Physical Therapy Modalities
chemical_list: D000894:Anti-Inflammatory Agents, Non-Steroidal
references.citation: J Orthop Sports Phys Ther. 2008 Jun;38(6):297-309; discussion 309-12
references.pmid: 18515959
references.citation: J Orthop Sports Phys Ther. 2012 Oct;42(10):823-30
references.pmid: 22951491
references.citation: J Orthop Sports Phys Ther. 2006 Nov;36(11):854-66
references.pmid: 17154139
references.citation: Arthroscopy. 1993;9(2):159-63
references.pmid: 8461073
references.citation: Am J Sports Med. 2010 Aug;38(8):1626-30
references.pmid: 20505056
references.citation: Scand J Med Sci Sports. 2002 Feb;12(1):40-6
references.pmid: 11985765
references.citation: Med Sci Sports Exerc. 2013 Jun;45(6):1120-4
references.pmid: 23274607
references.citation: J Orthop Sports Phys Ther. 2012 Jan;42(1):22-9
references.pmid: 22027216
references.citation: Br J Sports Med. 2012 Mar;46(4):247-52
references.pmid: 21930514
references.citation: Sports Med. 2012 Jan 1;42(1):31-49
references.pmid: 22149696
references.citation: Physiother Res Int. 2011 Jun;16(2):109-19
references.pmid: 20632302
references.citation: Br J Sports Med. 2013 Mar;47(4):193-206
references.pmid: 22815424
references.citation: Br J Sports Med. 2013 Mar;47(4):227-33
references.pmid: 23242955
references.citation: Sports Health. 2012 Mar;4(2):115-20
references.pmid: 23016077
references.citation: BMC Musculoskelet Disord. 2010 Jan 19;11:11
references.pmid: 20082723
references.citation: Am J Sports Med. 2002 Nov-Dec;30(6):857-65
references.pmid: 12435653
references.citation: Sports Med. 2010 May 1;40(5):377-95
references.pmid: 20433211
references.citation: J Orthop Sports Phys Ther. 2012 Feb;42(2):81-94
references.pmid: 22031622
references.citation: J Orthop Sports Phys Ther. 2012 Jun;42(6):A1-54
references.pmid: 22660660
references.citation: J Pediatr Orthop. 1998 Jan-Feb;18(1):118-22
references.pmid: 9449112
references.citation: Int J Sports Phys Ther. 2013 Oct;8(5):689-700
references.pmid: 24175148
references.citation: Clin J Sport Med. 1997 Jan;7(1):28-31
references.pmid: 9117522
references.citation: Cochrane Database Syst Rev. 2002;(2):CD002267
references.pmid: 12076444
references.citation: Med Sci Sports Exerc. 1994 Mar;26(3):289-96
references.pmid: 8183092
references.citation: Br J Gen Pract. 2007 Aug;57(541):655-61
references.pmid: 17688762
references.citation: Med Sci Sports Exerc. 1998 Nov;30(11):1572-7
references.pmid: 9813868
references.citation: Br J Sports Med. 2011 Jul;45(9):697-701
references.pmid: 21081642
references.citation: Br J Sports Med. 2010 Sep;44(12):862-6
references.pmid: 18819958
references.citation: Clin Rehabil. 2008 Dec;22(12):1051-60
references.pmid: 19052244
references.citation: Br J Sports Med. 2014 Mar;48(6):417-24
references.pmid: 24311602
references.citation: Skeletal Radiol. 2009 Sep;38(9):895-901
references.pmid: 19381628
references.citation: Am J Sports Med. 2004 Jul-Aug;32(5):1122-30
references.pmid: 15262632
references.citation: Knee. 2003 Jun;10(2):139-43
references.pmid: 12787996
references.citation: Br J Sports Med. 2002 Apr;36(2):95-101
references.pmid: 11916889
references.citation: J Orthop Sports Phys Ther. 2011 Aug;41(8):560-70
references.pmid: 21654093
references.citation: Med Sci Sports Exerc. 2011 Sep;43(9):1603-10
references.pmid: 21311359
references.citation: BMJ. 2008 Oct 24;337:a1735
references.pmid: 18952682
references.citation: Phys Ther. 2004 Jan;84(1):49-61
references.pmid: 14992676
references.citation: Sports Med. 2008;38(9):759-79
references.pmid: 18712943
references.citation: Spine (Phila Pa 1976). 2003 Jun 15;28(12):1290-9
references.pmid: 12811274
references.citation: J Man Manip Ther. 2012 Aug;20(3):113-20
references.pmid: 23904749
references.citation: Med Sci Sports Exerc. 2012 Oct;44(10):1827-33
references.pmid: 22617398
references.citation: Phys Ther. 2010 Jun;90(6):843-54
references.pmid: 20413577
references.citation: J Orthop Sports Phys Ther. 2008 Sep;38(9):529-41
references.pmid: 18758046
references.citation: J Clin Epidemiol. 1996 Dec;49(12):1373-9
references.pmid: 8970487
references.citation: J Rehabil Med. 2009 Jul;41(8):604-12
references.pmid: 19565153