Abstract
The Quadriceps or Q-angle is an index of the vector for the combined pull of the extensor mechanisms and the patellar tendon. It is used as an indicator for patellofemoral joint dysfunction. The purpose of this article is to systematically review and appraise the literature to determine the reliability and validity of this test. An electronic database search was performed accessing AMED, British Nursing Index, CINAHL, the Cochrane database, EMBASE, ovid Medline, Physiotherapy Evidence Database (PEDro), PsycINFO, Pubmed and Zetoc to April 2008. All English language, human subject, clinical trials, assessing the inter- or intra-tester reliability, or the criterion validity, were included. The Critical Appraisal Skills Programme appraisal tool was used to establish the methodological quality of each study. Ten articles including 569 control and 179 patellofemoral disorder knees were reviewed. The findings suggest that there is considerable disagreement on the reliability and validity of the clinical Q-angle measurement. This may be due to a lack of standardisation in the measurement procedure. Further study is advocated to re-evaluate this topic using well-designed, and sufficiently large observational studies of specific patellofemoral dysfunction populations.
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References
Ando T, Hirose H, Inoue M, Shino K, Doi T (1993) A new method using computed tomographic scan to measure the rectus femoris-patellar tendon Q-angle comparison with conventional method. Clin Orthop Relat Res 289:213–219
Arno SA (1990) The A-angle: a quantitative measurement of patella alignment and realignment. J Orthop Sports Phys Therp 12:237–242
Biedert RM, Warnke K (2001) Correlation between the Q angle and the patella position: a clinical and axial computed tomography evaluation. Arch Orthop Trauma Surg 121:346–349
Boden BP, Pearsall AW, Garrett WE Jr, Feagin JA Jr (1997) Patellofemoral instability: evaluation and management. J Am Acad Orthop Surg 5:47–57
Brindle TJ, Mattacola C, McCrory J (2003) Electromyographic changes in the gluteus medius during stair ascent and descent in subjects with anterior knee pain. Knee Surg Sports Traumatol Arthrosc 11:244–251
Brattström H (1964) Shape of the intercondylar groove normally and in recurrent dislocation of the patella. Acta Orthop Scand 68(Suppl):S1–S44
Brunet ME, Brinker MR, Cook SD, Christakis P, Fong B, Patron L, O’Connor DP (2003) Patellar tracking during simulated quadriceps contraction. Clin Orthop Relat Res 414:266–275
Brushøj C, Hölmich P, Nielsen MB, Albrecht-Beste E (2008) Acute patellofemoral pain: aggravating activities, clinical examination, MRI and ultrasound findings. Br J Sport Med 42:64–67
CASP (2007) Critical Skills Appraisal Programme. Learning & Development Public Health Resource Unit. Available from: http://www.phru.nhs.uk/casp/critical_appraisal_tools.htm
Caylor D, Fites R, Worrell TW (1993) The relationship between quadriceps angle and anterior knee pain syndrome. J Orthop Sport Phys Ther 17:11–16
Chester R, Smith TO, Sweeting D, Dixon J, Wood S, Song F (2008) The relative timing of VMO and VL in anterior knee pain: a systematic review and meta-analysis. BMC Musculoskelet Disord 9:64
Crossley KM, Bennell KL, Cowan SM, Green S (2004) Analysis of outcome measures for persons with patellofemoral pain: which are reliable and valid? Arch Phys Med Rehabil 85:815–822
Donell S (2006) Patellofemoral dysfunction—extensor mechanisms malalignment. Curr Orthop 20:103–111
Egger M, Davey Smith G, Schneider M (2001) Systematic reviews of observational studies. In: Egger M, Davey Smith G, Altman DG (eds) Systematic reviews in health care. BMJ Books, London, pp 211–228
Emami MJ, Ghahramani MH, Abdinejad F, Namazi H (2007) Q-angle: an invaluable parameter for evaluation of anterior knee pain. Arch Iran Med 10:24–26
Evans R, Elwyn G, Edwards A (2004) Review of instruments for peer assessment of physicians BMJ 328:1240
Fairbank JC, Pynsent PB, van Poortvliet JA, Phillips H (1984) Mechanical factors in the incidence of knee pain in adolescents and young adults. J Bone Joint Surg 66-B:685–693
France L, Nester C (2001) Effect of errors in the identification of anatomical landmarks on the accuracy of Q angle values. Clin Biomech 16:710–713
Fredericson M, Yoon K (2006) Physical examination and patellofemoral pain syndrome. Am J Phys Med Rehabil 85:234–243
Fulkerson JP (1994) Patellofemoral pain disorders: evaluation and management. J Am Acad Ortho Surg 2:124–132
Fulkerson JP, Kalenak A, Rosenberg TD, Cox JS (1992) Patellofemoral pain. Instr Course Lect 41:57–71
Greene CC, Edwards TB, Wade MR, Carson EW (2001) Reliability of the Quadriceps angle measurement. Am J Knee Surg 14:97–103
Grelsamer RP (2000) Current Concept Review. Patellar Malalignment. J Bone Joint Surg 82-A:1639–1650
Grelsamer RP, Dubey A, Weinstein CH (2005) Men and women have similar Q angles: a clinical and trigonometric evaluation. J Bone Joint Surg 87:1498–1501
Grelsamer RP, Klein JR (1998) The biomechanics of the patellofemoral joint. J Orthop Sport Phys Ther 28:286–298
Grelsamer RP, Newton PM, Staron RB (1998) The medial-lateral position of the patella on routine magnetic resonance imaging: when is normal not normal? Arthroscopy 14:23–28
Guerra JP, Arnold MJ, Gajdosik RL (1994) Q-angle: effects of isometric quadriceps contraction and body position. J Orthop Sport Phys Ther 19:200–204
Herrington L (2006) The effect of corrective taping of the patella on patella position as defined by MRI. Res Sport Med 14:215–223
Herrington L, Nester C (2004) Q-angle undervalued? The relationship between Q-angle and medio-lateral position of the patella. Clin Biomech 19:1070–1073
Horton MG, Hall TL (1998) Quadriceps femoris muscle angle: normal values and relationships with gender and selected skeletal measures. Phys Ther 69:897–901
Hughston JC, Walsh WM, Puddu G (1984) Patellar subluxation and dislocation. Saunders Co, Philadelphia, pp 21–40
Insall J, Falvo KA, Wise DW (1976) Chondromalacia Patellae. A prospective study. J Bone Joint Surg 58-A:1–8
Landis JR, Kock GG (1977) The measurement of observer agreement for categorical data. Biometrics 33:159–174
Lee TQ, Morris G, Csintalan RP (2003) The influence of tibial and femoral rotation on patellofemoral contact area and pressure. J Orthop Sport Phys Ther 33:686–693
Livingston LA (1998) The Quadriceps angle: a review of the literature. J Orthop Sport Phys Ther 28:105–109
Livingston LA, Mandigo JL (1999) Bilateral Q angle asymmetry and anterior knee pain syndrome. Clin Biomech 14:7–13
Kannus P, Niittymaki S (1994) Which factors predict outcome in the nonoperative treatment of patellofemoral pain syndrome? A prospective follow-up study. Med Sci Sports Exerc 26:289–296
Karlsson J, Thomeé R, Swärd L (1996) Eleven year follow-up of patello-femoral pain syndrome. Clin J Sport Med 6:22–26
Kolowich PA, Paulos LE, Rosenberg TD, Farnsworth S (1990) Lateral release of the patella: indications and contraindications. Am J Sports Med 18:359–365
McConnell J (1986) The management of chondromlacia patellae: a long term solution. Aust J Physiother 32:215–223
Messier SP, Davis SE, Curl WW, Lowery RB, Pack RJ (1991) Etiologic factors associated with patellofemoral pain in runners. Med Sci Sports Exerc 23:1008–1015
Mizuno Y, Kumagai M, Mattessich SM, Eilas JJ, Ramrattan N, Cosgarea AJ, Chao EYS (2001) Q-angle influences tibiofemoral and patellofemoral kinematics. J Orthop Res 19:834–840
Nagamine R, Otani T, White SE, McCarthy D, Whiteside LA (1995) Patellar tracking measurement in the normal knee. J Orthop Res 13:115–122
Nissen CW, Cullen MC, Hewett TE, Noyes FR (1998) Physical and arthroscopic examination techniques of the patellofemoral joint. J Orthop Sport Phys Ther 28:277–285
Piva SR, Fitzgerald K, Irrgang JJ, Jones S, Hando BR, Browder DA, Childs JD (2006) Reliability of measures of impairments associated with patellofemoral pain syndrome. BMC Musculoskelet Disord 31:33
Polgar S, Thomas SA (2000) Introduction to research in the health sciences, 4th edn. Churchill Livingstone, London, pp 136–140
Powers CM (2003) The influence of altered lower-extremity kinematics on patellofemoral joint dysfunction: a theoretical perspective. J Orthop Sport Phys Ther 33:639–646
Powers CM, Maffucci R, Hampton S (1995) Rearfoot posture in subjects with patellofemoral pain. J Orthop Sports Phys Ther 22:155–160
Reider B, Marshall JL, Warren RF (1981) Clinical characteristics of patellar disorders in young athletes. Am J Sports Med 9:270–274
Rothstein HR, Sutton AJ, Borenstein M (2005) Publication bias in meta-analysis. In: Rothstein HR, Sutton AJ, Borenstein M (eds) Publication bias in meta-analysis. Prevention assessment and adjustment. Wiley, Chichester, pp 1–7
Sanfridsson J, Arnbjörnsson A, Fridén T, Ryd L, Svahn G, Jonsson K (2001) Femorotibial rotation and the Q-angle related to the dislocating patella. Acta Radiol 42:218–224
Schulthies SS, Francis RS, Fisher AG, Van de Graaff KM (1995) Does the Q angle reflect the force on the patella in the frontal plane? Phys Ther 75:24–30
Sendur OF, Gurer G, Yildirim T, Ozturk E, Aydeniz A (2006) Relationship of Q angle and joint hypermobility and Q angle values in different positions. Clin Rheumatol 25:304–308
Shultz SJ, Nguyen AD, Windley TC, Kulas AS, Botic TL, Beynnon BD (2006) Intratester and intertester reliability of clinical measures of lower extremity anatomic characteristics: implications for multicenter studies. Clin J Sport Med 16:155–161
Söjbjerg TO, Lauritzen J, Hvid I, Boe S et al (1987) Arthroscopic determination of patellofemoral malalignment. Clin Orthop 215:243–247
Song F, Eastwood AJ, Gilbody S, Duley L, Sutton AJ (2000) Publication and related biases. Health Technol Assess 4:1–115
Thomeé R, Renström P, Karlsson J, Grimby G (1995) Patellofemoral pain syndrome in young women. I. A clinical analysis of alignment, pain parameters, common symptoms and functional activity level. Scand J Med Sci Sports 5:237–244
Tomsich DA, Nitz AJ, Thelkeld AJ, Shapiro R (1996) Patellofemoral alignment: reliability. J Orthop Sport Phys Ther 23:200–208
Tsujimoto K, Kurosaka M, Yoshiya S, Mizuno K (2000) Radiographic and computed tomographic analysis of the position of the tibial tubercle in recurrent dislocation and subluxation of the patella. Am J Knee Surg 13:83–88
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We thank Miss Kate Hulse for her assistance with the photographs used in this study.
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Smith, T.O., Hunt, N.J. & Donell, S.T. The reliability and validity of the Q-angle: a systematic review. Knee Surg Sports Traumatol Arthr 16, 1068–1079 (2008). https://doi.org/10.1007/s00167-008-0643-6
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DOI: https://doi.org/10.1007/s00167-008-0643-6