Risk assessment and management of primary patellar dislocation is complex and multifactorial: a survey of Australian knee surgeons

J ISAKOS. 2021 Nov;6(6):333-338. doi: 10.1136/jisakos-2020-000609. Epub 2021 Jun 4.


Objectives: Recurrent patellar instability following first-time lateral patellar dislocation is associated with a variety of bony, soft tissue and patient-related risk factors. The specific management of recurrent dislocation may vary depending on the presence and combination of these factors as well as the treating physician's interpretation of these. Therefore, this study aimed to determine which factors Australian knee surgeons regard as increasing the risk of recurrence following first-time patellar dislocation and to characterise the surgical decision-making process of these surgeons in the management of lateral patellar instability.

Methods: An online survey was sent to all active members of the Australian Knee Society (AKS). The survey addressed (i) risk factors for recurrence following first-time patellar dislocation and (ii) the surgical decision-making process in treating patellar instability.

Results: Seventy-seven per cent (53 of 69) Australian Knee Society members responded. Factors identified by respondents as significantly increasing the risk of recurrence were a history of contralateral recurrent patellar dislocation (74% respondents), an atraumatic injury mechanism (57%), trochlear dysplasia (49%) younger age (45%), patella alta (43%) and generalised ligamentous laxity (42%). Forty-four per cent replied that there may be an indication for surgical intervention following first-time patellar dislocation with no apparent loose body present. All respondents would recommend operative management of recurrent patellar dislocation after a third episode, with 45% of surgeons recommending surgery after a second episode. The most common surgical procedures performed by respondents were medial patellofemoral ligament (MPFL) reconstruction (94%), tibial tuberosity medialisation (91%) and tibial tuberosity distalisation (85%). Only 23% of respondents consider trochleoplasty for primary surgical intervention.

Conclusion: Surgeons identified a large number of factors that they use to assess risk of recurrence following first-time patellar dislocation, many of which are not supported by the literature. The two highest ranked factors (history of contralateral recurrent patellar dislocation and an atraumatic injury mechanism) are without a significant evidence base. There was considerable variation in the criteria used to make the decision to perform a patellar stabilisation procedure. MPFL reconstruction was the most commonly used procedure, either in isolation or combined with another procedure.

Level of evidence: Cross-sectional study; expert opinion (Level V).

Keywords: joint dislocations; knee; knee injuries; orthopaedic sports medicine.

MeSH terms

  • Australia / epidemiology
  • Cross-Sectional Studies
  • Humans
  • Joint Instability* / diagnostic imaging
  • Patellar Dislocation* / diagnostic imaging
  • Patellofemoral Joint*
  • Risk Assessment
  • Surgeons*
  • Surveys and Questionnaires