Patellar tendon shortening following patellofemoral joint replacement

  • Ludo A. H. van Engen
  • Ellie B. M. Landman
  • Ydo V. Kleinlugtenbelt
  • Hans-Peter W. van JonbergenEmail author
Original Paper



Patellar tendon shortening may occur following patellofemoral joint replacement (PFJR). We hypothesized that patellar tendon shortening results in unfavourable patient-reported outcomes (PROs). The aim of this study was to determine the effect of patellar tendon shortening following PFJR on PROs.


In this substudy of a prospective cohort study, a total of 108 patients with isolated patellofemoral osteoarthritis underwent 124 patellofemoral joint replacements. We measured both patellar tendon length and length of the patella on pre-operative radiographs, and on radiographs acquired at eight weeks and at one year post-operative. More than 10% decrease in patellar tendon length relative to the pre-operative patellar tendon length was defined as patellar tendon shortening. Clinical outcomes were assessed using the knee-specific KOOS questionnaire (Knee Injury and Osteoarthritis Outcome Score). Repeated measures ANOVA was used to analyze for differences in change from baseline KOOS subscales between patients with and patients without patellar tendon shortening.


A complete series of standardized pre-operative, eight weeks and one year post-operative radiographs was available for 87 knees in 82 patients. At eight weeks, 16 of 87 knees (18%) showed patellar tendon length shortening, and 27 of 87 knees (31%) at one year. We found no statistically significant relation between patellar tendon length shortening and change from baseline KOOS subscales at one year follow-up (pain p = 0.29, symptoms p = 0.56, ADL p = 0.23, sport or recreation p = 0.22, knee-related quality of life (QOL) p = 0.15).


Patellar tendon length shortening following PFJR occurs in 31% of knees at one year, and does not result in inferior PROs.


Patellar tendon shortening Patellofemoral joint replacement Patient-reported outcomes KOOS 


Compliance with ethical standards

Conflict of interest

The authors declare that they have no conflict of interest.


  1. 1.
    Noyes FR, Wojtys EM, Marshall MT (1991) The early diagnosis and treatment of developmental patella infera syndrome. Clin Orthop Relat Res 265:241–252Google Scholar
  2. 2.
    Mariani PP, Del Signore S, Perugia L (1994) Early development of patella infera after knee fractures. Knee Surg Sports Traumatol Arthrosc 2:166–169CrossRefGoogle Scholar
  3. 3.
    Weale AE, Murray DW, Newman JH, Ackroyd CE (1999) The length of the patellar tendon after unicompartmental and total knee replacement. J Bone Joint Surg Br 81:790–795CrossRefGoogle Scholar
  4. 4.
    Floren M, Davis J, Peterson MG, Laskin RS (2007) A mini-midvastus capsular approach with patellar displacement decreases the prevalence of patella baja. J Arthroplast 22:51–57CrossRefGoogle Scholar
  5. 5.
    Jawhar A, Sohoni S, Shah V, Scharf HP (2014) Alteration of the patellar height following total knee arthroplasty. Arch Orthop Trauma Surg 134:91–97CrossRefGoogle Scholar
  6. 6.
    Davies GS, van Duren B, Shorthose M, Garfjeld Roberts P, Morley JR, Monk AP, Murray DW, Pandit HG (2016) Changes in patella tendon length over 5 years after different types of knee arthroplasty. Knee Surg Sports Traumatol Arthrosc 24:3029–3035CrossRefGoogle Scholar
  7. 7.
    Lemon M, Packham I, Narang K, Craig DM (2007) Patellar tendon length after knee arthroplasty with and without preservation of the infrapatellar fat pad. J Arthroplast 22:574–580CrossRefGoogle Scholar
  8. 8.
    Gwyn R, Kotwal RS, Holt MD, Davies AP (2016) Complete excision of the infrapatellar fat pad is associated with patellar tendon shortening after primary total knee arthroplasty. Eur J Orthop Surg Traumatol 26:545–549CrossRefGoogle Scholar
  9. 9.
    Paulos LE, Wnorowski DC, Greenwald AE (1994) Infrapatellar contracture syndrome. Diagnosis, treatment, and long-term followup. Am J Sports Med 22:440–449CrossRefGoogle Scholar
  10. 10.
    Anagnostakos K, Lorbach O, Kohn D (2012) Patella baja after unicompartmental knee arthroplasty. Knee Surg Sports Traumatol Arthrosc 20:1456–1462CrossRefGoogle Scholar
  11. 11.
    Clark D, Mandalia V, Hughes A, Mitchell S, Bhattacharjee A, Eldridge J (2012) Patella tendon length after patella arthroplasty. Arch Orthop Trauma Surg 132:179–183CrossRefGoogle Scholar
  12. 12.
    Meneghini RM, Ritter MA, Pierson JL, Meding JB, Berend ME, Faris PM (2006) The effect of the Insall-Salvati ratio on outcome after total knee arthroplasty. J Arthroplast 21:116–120CrossRefGoogle Scholar
  13. 13.
    Iwano T, Kurosawa H, Tokuyama H, Hoshikawa Y (1990) Roentgenographic and clinical findings of patellofemoral osteoarthrosis. With special reference to its relationship to femorotibial osteoarthrosis and etiologic factors. Clin Orthop 252:190–197Google Scholar
  14. 14.
    van Jonbergen HPW, Westerbeek RE (2018) Femoral component rotation in patellofemoral joint replacement. Knee 25:485–490CrossRefGoogle Scholar
  15. 15.
    Assi C, Kheir N, Samaha C, Deeb M, Yammine K (2017) Optimizing patellar positioning during total knee arthroplasty: an anatomical and clinical study. Int Orthop 41:2509–2515CrossRefGoogle Scholar
  16. 16.
    de Groot IB, Favejee MM, Reijman M, Verhaar JA, Terwee CB (2008) The Dutch version of the Knee Injury and Osteoarthritis Outcome Score: a validation study. Health Qual Life Outcomes 6:16CrossRefGoogle Scholar
  17. 17.
    Roos EM, Toksvig-Larsen S (2003) Knee injury and Osteoarthritis Outcome Score (KOOS) - validation and comparison to the WOMAC in total knee replacement. Health Qual Life Outcomes 1:17CrossRefGoogle Scholar
  18. 18.
    Insall J, Salvati E (1971) Patella position in the normal knee joint. Radiology 101:101–104CrossRefGoogle Scholar
  19. 19.
    Cicchetti DV (1994) Multiple comparison methods: establishing guidelines for their valid application in neuropsychological research. J Clin Exp Neuropsychol 16:155–161CrossRefGoogle Scholar
  20. 20.
    Drexler M, Dwyer T, Marmor M, Sternheim A, Cameron HU, Cameron JC (2013) The treatment of acquired patella baja with proximalize the tibial tuberosity. Knee Surg Sports Traumatol Arthrosc 21:2578–2583CrossRefGoogle Scholar
  21. 21.
    Huang AB, Wang HJ, Yu JK, Yang B, Ma D, Zhang JY (2016) Optimal patellar alignment with minimally invasive approaches in total knee arthroplasty after a minimum five year follow-up. Int Orthop 40:487–492CrossRefGoogle Scholar
  22. 22.
    Prudhon JL, Caton JH, Aslanian T, Verdier R (2018) How is patella height modified after total knee arthroplasty? Int Orthop 42:311–316CrossRefGoogle Scholar

Copyright information

© SICOT aisbl 2018

Authors and Affiliations

  • Ludo A. H. van Engen
    • 1
  • Ellie B. M. Landman
    • 1
  • Ydo V. Kleinlugtenbelt
    • 1
  • Hans-Peter W. van Jonbergen
    • 1
    Email author
  1. 1.Department of Orthopedic and Trauma SurgeryDeventer HospitalDeventerThe Netherlands

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