Top

Knee Surgery, Sports Traumatology, Arthroscopy

Published in:

01-02-2014 | Knee

The development, validation and internal consistency of the Norwich Patellar Instability (NPI) score

Authors: Toby O. Smith, Simon T. Donell, Allan Clark, Rachel Chester, Jane Cross, Deiary F. Kader, Elizabeth A. Arendt

Published in: Knee Surgery, Sports Traumatology, Arthroscopy | Issue 2/2014

Abstract

Purpose

No outcome measurements have previously been designed to assess patient-perceived patellar instability. The purposes of this study were to address this limitation and to describe the development and validation of the Norwich Patellar Instability (NPI) scores, a self-administered 19-item questionnaire to assess perceived patellar instability.

Methods

A previous study assessed activities that aggravated symptoms in individuals with patellar dislocation and instability symptoms. These reported activities were ranked in order of severity, and a weighting system was calculated. The NPI score was introduced to routine clinical practice in three institutions. One hundred and two people who had experienced a lateral patellar dislocation completed 102 NPI questionnaires. The completed NPI score was correlated with the Knee injury and Osteoarthritis Outcome Score (KOOS) to evaluate divergent validity and with the J-sign, patellar mobility, apprehension test, Beighton score, Kujala Patellofemoral Disorder Score and Lysholm Knee Score to evaluate convergent validity. Internal consistency of the 19 items was also calculated.

Results

The results indicated a moderate correlation between the NPI score and the Kujala Patellofemoral Disorder Score (rho = −0.66; p < 0.01) and Lysholm Knee Score (rho = −0.54; p = 0.03), suggesting good convergent validity. There was a little correlation between the KOOS and NPI score, indicating divergent validity (rho = −0.02 to −0.17; n.s.). There was high internal consistency (Cronbach’s alpha = 0.93).

Conclusion

These results indicate the NPI score to be a valid tool to assess patellar instability for individuals following patellar dislocation. Further study is now required in order to assess the reliability and responsiveness of this new outcome measure.

Level of evidence

III.

Aglietti P, Buzzi R, Insall JN (2001) Disorders of the patellofemoral joint. In: Insall JN, Scott WN (eds) Surgery of the knee, 3rd edn. Churchill Livingstone, Philadelphia

Atkin DM, Fithian DC, Marangi KS, Stone ML, Dobson BE, Mendelsohn C (2000) Characteristics of patients with primary acute lateral patellar dislocation and their recovery within the first 6 months of injury. Am J Sports Med 28:472–479PubMed

Beighton PH, Horan F (1969) Orthopedic aspects of the Ehlers-Danlos syndrome. J Bone Joint Surg [Br] 51:444–453

Bland M (2006) An Introduction to medial statistics, 3rd edn. Oxford University Press, Oxford

Brukner P, Khan K (2003) Clinical sports medicine, 2nd edn. McGraw-Hill Companies, Inc., London

Cash JD, Hughston JC (1988) Treatment of acute patellar dislocation. Am J Sports Med 16:244–249PubMedCrossRef

Draper CE, Besier TF, Santos JM, Jennings F, Fredericson M, Gold GE, Beaupre GS, Delp SL (2009) Using real-time MRI to quantify altered joint kinematics in subjects with patellofemoral pain and to evaluate the effects of a patellar brace or sleeve on joint motion. J Orthop Res 27:571–577PubMedCentralPubMedCrossRef

Donell S (2006) Patellofemoral dysfunction-Extensor mechanisms malalignment. Curr Orthop 20:103–111CrossRef

Fithian DC, Paxton EW, Cohen AB (2004) Indications in the treatment of patellar instability. J Knee Surg 17:47–56PubMed

10.

Fithian DC, Paxton EW, Stone ML, Silva P, Davis DK, Elias DA, White LM (2004) Epidemiology and natural history of acute patellar dislocation. Am J Sports Med 32:1114–1121PubMedCrossRef

11.

Fulkerson JP, Shea KP (1990) Disorders of the patellofemoral alignment. J Bone Jt Surg 72 A:1424–1429

12.

Grelsamer RP (2000) Current concept review. Patellar malalignment. J Bone Jt Surg 82 A:1639–1650

13.

Grelsamer RP (1997) Patellofemoral semantics. The Tower of Babel. The International Patellofemoral Study group. Am J Knee Surg 10:92–95

14.

Hefti F, Muller W, Jakob RP, Staubli HU (1993) Evaluation of knee ligament injuries with the IKDC form. Knee Surg Sports Traumatol Arthrosc 1:226–234PubMedCrossRef

15.

Hulley SB, Cummings SR, Browner WS, Grady DG, Newman TB (2007) Designing clinical research. Wolters Kluwer Health, 3rd edn. Lippincott Williams & Wilkins, London

16.

Kujala UM, Jaakkola LH, Koskinen SK, Taimela S, Hurme M, Nelimarkka O (1993) Scoring of patellofemoral disorders. Arthroscopy 9:159–163PubMedCrossRef

17.

Lysholm J, Gillquist J (1982) Evaluation of knee ligament surgery results with special emphasis on use of a scoring scale. Am J Sports Med 10:150–154PubMedCrossRef

18.

McConnell J (2007) Rehabilitation and nonoperative treatment of patellar instability. Sports Med Arthrosc Rev 15:95–104CrossRef

19.

Medical Outcomes Trust Scientific Advisory Committee (2002) Assessing health status and quality of life instruments: attributes and review criteria. Qual Life Res 11:193–205CrossRef

20.

Nietosvaara Y, Aalto K, Kallio PE (1994) Acute patellar dislocation in children: incidence and associated osteochondral fractures. J Pediatr Orthop 14:513–515PubMedCrossRef

21.

Nomura E, Inoue M, Kobayashi S (2006) Generalized joint laxity and contralateral patellar hypermobility in unilateral recurrent patellar dislocators. Arthroscopy 22:861–865PubMedCrossRef

22.

Palmu S, Kallio PE, Donell ST, Helenius I, Nietosvaara Y (2008) Acute patellar dislocation in children and adolescents: a randomized clinical trial. J Bone Jt Surg 90 A:463–470CrossRef

23.

Paxton EW, Fithian DC, Stone ML, Silva P (2003) The reliability and validity of knee-specific and general health instruments in assessing acute patellar dislocation outcomes. Am J Sports Med 31:487–492PubMed

24.

Portney LG, Watkins MP (2009) Foundations of clinical research, 3rd edn. Applications to practice, Pearson Prentice Hall

25.

Powers CM, Shellock FG, Pfaff M (1998) Quantification of patellar tracking using kinematic MRI. J Magn Reson Imaging 8:724–732PubMedCrossRef

26.

Roos EM, Roos HP, Lohmander LS, Ekdahl C, Beynnon BD (1998) Knee injury and osteoarthritis outcome score (KOOS)–development of a self-administered outcome measure. J Orthop Sports Phys Ther 28:88–96PubMedCrossRef

27.

Scudero GR, McCann PD (2005) Sports medicine. A comprehensive approach, 2nd edn. Elsevier Mosby, Philadelphia

28.

Sillanpää PJ, Mäenpää HM, Mattila VM, Visuri T, Pihlajamäki H (2008) Arthroscopic surgery for primary traumatic patellar dislocation. A prospective, nonrandomized study comparing patients treated with and without acute arthroscopic stabilization with a median 7-year follow-up. Am J Sport Med 36:2301–2309CrossRef

29.

Sillanpää P, Mattila VM, Iivonen T, Visuri T, Pihlajamäki H (2008) Incidence and risk factors of acute traumatic primary patellar dislocation. Med Sci Sports Exerc 40:606–611PubMedCrossRef

30.

Sillanpää PJ, Mattila VM, Mäenpää H, Kiuru M, Visuri T, Pihlajamäki H (2009) Treatment with and without initial stabilizing surgery for primary traumatic patellar Dislocation. J Bone Jt Surg 91-A:263–273CrossRef

31.

Smith TO, Davies L, O’Driscoll M-L, Donell ST (2008) An evaluation of the clinical tests and outcome measures used to assess patellar instability. Knee 15:255–262PubMedCrossRef

32.

Smith TO, Donell ST, Chester R, Clark A, Stephenson RC (2011) What activities do patients with patellar instability perceive their patella to be unstable? Knee 18:333–339PubMedCrossRef

33.

Streiner DL, Normal GR (2008) Health measurement scales: a practical guide to their development and use, 3rd edn. Oxford University Press, Oxford, pp 263–265CrossRef

34.

Tegner Y, Lysholm J (1985) Rating systems in the evaluation of knee ligament injuries. Clin Orthop Relat Res 198:43–49PubMed

35.

Woo R, Busch MT (1998) Management of patellar instability in children. Operat Techn Sports Med 6:247–258CrossRef

Title: The development, validation and internal consistency of the Norwich Patellar Instability (NPI) score
Authors: Toby O. Smith
Simon T. Donell
Allan Clark
Rachel Chester
Jane Cross
Deiary F. Kader
Elizabeth A. Arendt
Publication date: 01-02-2014
Publisher: Springer Berlin Heidelberg
Published in: Knee Surgery, Sports Traumatology, Arthroscopy / Issue 2/2014
Print ISSN: 0942-2056
Electronic ISSN: 1433-7347
DOI: https://doi.org/10.1007/s00167-012-2359-x

At a glance: The ONWARDS insulin icodec trials

Springer Medicine

The development, validation and internal consistency of the Norwich Patellar Instability (NPI) score

Abstract

Purpose

Methods

Results

Conclusion

Level of evidence

At a glance: The ONWARDS insulin icodec trials

Springer Medicine

Abstract

Purpose

Methods

Results

Conclusion

Level of evidence

Please log in to get access to this content

Other articles of this Issue 2/2014

The use of a mono-fluted reamer results in decreased enlargement of the tibial tunnel when using a transtibial ACL reconstruction technique

Acromial morphology in patients with calcific tendinitis of the shoulder

Arthroscopically assisted percutaneous fixation of displaced midclavicular fracture using a Knowles pin

Outcomes after ACL reconstruction with focus on older patients: results from The Swedish National Anterior Cruciate Ligament Register

Has the arthroscopically assisted reduction of acute AC joint separations with the double tight-rope technique advantages over the clavicular hook plate fixation?

Anatomic and histologic analysis of the mid-substance and fan-like extension fibres of the anterior cruciate ligament during knee motion, with special reference to the femoral attachment