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  • Oral presentation
  • Open Access

Postural control in total knee arthroplasty patients with patellofemoral pain syndrome before and six months after re-operation

  • 1Email author,
  • 2,
  • 2,
  • 1,
  • 1 and
  • 1
Journal of Foot and Ankle Research20125 (Suppl 1) :O33

  • Published:


  • Total Knee Arthroplasty
  • Anterior Knee Pain
  • Plantar Pressure
  • Total Knee Arthroplasty Patient
  • Patellofemoral Pain Syndrome


Although excellent long-term clinical results have been reported for the total knee arthroplasty (TKA), 37% of patients have limited functional improvement one year after the surgery [1]. Patients with a clinical presentation of anterior knee pain could be diagnosed with patellofemoral pain syndrome (PFPS). Modified clinical classification of PFPS patients includes two main groups: with malalignment and with muscular dysfunction [2]. The aim of the study was to compare postural stability characteristics in TKA patients with PFPS before and six months after re-operation.

Materials and methods

Twelve patients aged 59-77 years with PFPS following unilateral TKA participated in the study. Pre-TKA, all patients had primary degenerative knee OA in stage III or IV (Kellgren-Lawrence Scale) and were scheduled for the first TKA. Duration of pain before TKA was 9.3±2.5 years and re-operation due to PFPS was performed 18.8±3.5 months later. Patella malalignment was noted in eight patients and patella altered position in three patients. Static standing balance was assessed by centre of foot pressure (COP) sway registered during 30 s quiet bipedal standing with eyes open on twin force plates Kistler 9286A (Switzerland) using Sway software of motion analysis system Elite (BTS S.p.A., Italy). Plantar pressure distribution was recorded by Digital Biometry Scanning System and Milletrix software (DIASU, Italy). Data are means and standard errors of means (±SE).


COP sway trace radius of PFPS leg was significantly shorter 6 month after re-operation as compared before it (5.91± 0.48 and 4.22 ± 0.22 mm, respectively, p=0.007). No significant difference was found in COP trace length and velocity as compared pre- and post-surgery data (p>0.05). Significant decrease of plantar pressure distribution in forefoot of PFPS leg was noted (p<0.05, Table 1).
Table 1

Plantar pressure distribution (weight ratio %) in TKA patients with PFPS before and 6 months after re-operation


Before re-operation

After re-operation



PFPS leg

66.37 ± 4.90

51.55 ± 1.64



Non-PFPS leg

64.15 ± 6.47

52.16 ± 3.40



PFPS leg

44.85 ± 1.75

51.54 ± 1.86



Non-PFPS leg

49.16 ± 3.36

47.84 ± 3.40



Main findings of our study were: (1) postural control in TKA patients with PFPS significantly improves (and 2) re-distribution of plantar pressure from forefoot to rearfoot in PFPS leg takes place 6 months after re-operation. The link between the segmental configuration of the lower limbs was described [3] and the importance of paying attention to balancing of the PF soft tissues was emphasized in studies of PF pain after TKA [4].



This study was supported by Estonian Ministry of Education and Research project No SF0180030s07 and Estonian Science Foundation project No 7939.

Authors’ Affiliations

Institute of Exercise Biology and Physiotherapy, University of Tartu, Tartu, 51014, Estonia
Department of Traumatology and Orthopaedics, University of Tartu, Tartu, 51014, Estonia


  1. Franklin PD, Li W, Ayers DC: The Chitranjan Ranawat Award: functional outcome after total knee replacement varies with patient attributes. Clin Orthop Relat Res. 2008, 466: 2597-2604. 10.1007/s11999-008-0428-8.PubMed CentralView ArticlePubMedGoogle Scholar
  2. Witvrouw E, et al: Clinical classification of patellofemoral pain syndrome: guidelines for non-operative treatment. Ortopedia Biomeccanica, Riabilitazione Sportiva. 7 Corso Internazionale. Assisi, 21-23 novembre 2003. 2003, Universita degli Studi – Azienda Ospedaliera, Perugia, 174-186.Google Scholar
  3. Roudiger PR: Relative contribution of the pressure variations under the feet and body weight distribution over both legs in the control of upright stance. J Biomech. 2007, 40: 2477-2482. 10.1016/j.jbiomech.2006.11.003.View ArticleGoogle Scholar
  4. Scuderi GR, Insall JN, Scott NW: Patellofemoral pain after total knee arthroplasty. J Am Acad Orthop Surg. 1994, 2: 239-246.PubMedGoogle Scholar


© Gapeyeva et al; licensee BioMed Central Ltd. 2012

This article is published under license to BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.